Rechargeable batteries and battery packs containing them

Abstract

This disclosure relates to a secondary battery and a battery pack including the same, and provides a secondary battery and a battery pack including the same with improved insulation performance. [Solution] To this end, the present disclosure provides a secondary battery comprising: a case; an electrode assembly disposed inside the case; a cap plate having a first surface facing the electrode assembly and a second surface opposite to the first surface; a terminal protruding outward from the cap plate and connected to the electrode assembly; and a gasket disposed between the cap plate and the terminal, having a first end in contact with the cap plate and a second end in contact with the terminal, wherein the creepage distance of the gasket is greater than the distance between the first end and the second end.

Description

Technical Field

[0001] The present disclosure relates to a secondary battery and a battery pack including the same.

Background Art

[0002] Generally, recently, with the rapid spread of electronic devices using batteries such as mobile phones, notebook computers, and electric vehicles, the demand for secondary batteries with high energy density and high capacity has been rapidly increasing. Along with this, research and development for improving the performance of lithium secondary batteries have been actively progressing.

[0003] A lithium secondary battery is a battery including a positive electrode and a negative electrode containing an active material capable of insertion (intercalation) and desorption (deintercalation) of lithium ions and an electrolyte, and produces electrical energy by oxidation and reduction reactions when lithium ions are inserted / desorbed at the positive electrode and the negative electrode.

[0004] The above-described information disclosed in the technology serving as the background of such an invention is only for improving the understanding of the background of the present invention, and thus may include information that does not constitute the prior art.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a secondary battery with improved insulation performance and a battery pack including the same.

[0006] However, the technical problems to be solved by the present invention are not limited to the above-described problems, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

Means for Solving the Problems

[0007] A secondary battery according to the present invention for solving the aforementioned technical problems includes a case, an electrode assembly disposed inside the case, a cap plate having a first surface facing the electrode assembly and a second surface opposite to the first surface, a terminal protruding to the outside of the cap plate and connected to the electrode assembly, and a gasket disposed between the cap plate and the terminal, having a first end in contact with the cap plate and a second end in contact with the terminal, wherein the creepage distance of the gasket is greater than the distance between the first end and the second end.

[0008] The gasket may include a first insulating surface extending from the first end toward the terminal, a second insulating surface extending from the second end toward the cap plate and separated from the first insulating surface, and a third insulating surface positioned between the first insulating surface and the second insulating surface.

[0009] The first insulating surface and the second insulating surface may be arranged parallel to the second surface.

[0010] The first insulating surface and the second insulating surface may be arranged on different planes from each other.

[0011] The second insulating surface may be positioned higher than the first insulating surface.

[0012] The first insulating surface may be positioned on the same plane as the second surface.

[0013] The third insulating surface may be positioned to intersect with the second surface.

[0014] The creepage distance of the gasket may be the sum of the creepage distance of the first insulating surface, the creepage distance of the second insulating surface, and the creepage distance of the third insulating surface.

[0015] The creepage distance of the gasket may be 6 mm or more and 10 mm or less.

[0016] The creepage distance of the second insulating surface may be smaller than the creepage distance of the first insulating surface.

[0017] The creepage distance of the second insulating surface may be between 1 mm and 4 mm.

[0018] The creepage distance of the third insulating surface may be 1 mm or more and 3 mm or less.

[0019] The gasket may further include a support surface that is separated from the first insulating surface and faces the electrode assembly.

[0020] The cross-sectional area of ​​the gasket may increase from the support surface toward the first insulating surface.

[0021] The cap plate may further include ribs that protrude from it and support the support surface.

[0022] The gasket may further include a fixing portion that extends from the support surface and is positioned to surround the rib.

[0023] The gasket may further include grooves formed to be recessed from at least one of the first insulating surface, the second insulating surface, and the third insulating surface.

[0024] The gasket may further include a filler protruding from any one of the first insulating surface, the second insulating surface, and the third insulating surface.

[0025] The terminal includes a first terminal surface facing the electrode assembly and a second terminal surface opposite to the first terminal surface, and the end of the filler may be positioned lower than the second terminal surface.

[0026] The battery pack according to the present invention includes a housing and a plurality of secondary batteries disposed inside the housing. The secondary battery includes a case, an electrode assembly disposed inside the case, a cap plate having a first surface facing the electrode assembly and a second surface opposite to the first surface, a terminal passing through the cap plate and connected to the electrode assembly, and a gasket disposed between the cap plate and the terminal and having a first end contacting the cap plate and a second end contacting the terminal. The creepage distance of the gasket is greater than the distance between the first end and the second end.

Advantages of the Invention

[0027] According to the present invention, the insulation resistance of the secondary battery can be improved by ensuring a sufficient insulation distance between the cap plate and the terminal.

[0028] However, the effects obtainable through the present invention are not limited to the effects described above, and other technical effects not mentioned will be clearly understood by those skilled in the art from the description of the invention below.

Brief Description of the Drawings

[0029] The following drawings attached to this specification illustrate preferred embodiments of the present invention and, together with the detailed description of the invention to be described later, serve to further understand the technical idea of the present invention. Therefore, the present invention should not be construed as being limited only to the matters described in such drawings. [Figure 1] It is a perspective view schematically showing the configuration of a battery pack according to an embodiment of the present invention. [Figure 2] It is a perspective view schematically showing the configuration of a secondary battery according to an embodiment of the present invention. [Figure 3] It is an exploded perspective view schematically showing the configuration of a secondary battery according to an embodiment of the present invention. [Figure 4] It is a drawing schematically showing the configuration of an electrode assembly according to an embodiment of the present invention. [Figure 5] This is a schematic perspective view showing the configuration of a terminal and gasket according to one embodiment of the present invention. [Figure 6] This is a schematic cross-sectional view showing the configuration of a terminal and gasket according to one embodiment of the present invention. [Figure 7] This is an enlarged diagram schematically showing the configuration of a gasket according to one embodiment of the present invention. [Figure 8] This is a schematic perspective view showing the configuration of a gasket according to another embodiment of the present invention. [Figure 9] This is a schematic cross-sectional view showing the configuration of a gasket according to another embodiment of the present invention. [Figure 10] This is an enlarged view schematically showing the configuration of the groove according to this embodiment. [Figure 11] This is a schematic perspective view showing the configuration of a gasket according to yet another embodiment of the present invention. [Figure 12] This is a schematic cross-sectional view showing the configuration of a gasket according to yet another embodiment of the present invention. [Figure 13] This is an enlarged diagram illustrating the schematic configuration of the filler according to this embodiment. [Modes for carrying out the invention]

[0030] Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in this specification and in the claims should not be interpreted restrictively in their usual or dictionary sense, but should be interpreted in a sense and concept consistent with the technical idea of ​​the present invention, in accordance with the principle that inventors can appropriately define the concepts of terms in order to best describe their invention. Accordingly, the embodiments described herein and the configurations illustrated in the drawings represent only some of the most preferred embodiments of the present invention and do not represent the entire technical idea of ​​the present invention, and it should be understood that there are various equivalents and modifications that can substitute for them at the time of filing.

[0031] Furthermore, as used herein, “comprise, include” and / or “comprising, including” identify the presence of the shapes, figures, stages, actions, members, elements and / or groups thereof mentioned, and do not exclude the presence or addition of one or more other shapes, figures, actions, members, elements and / or groups thereof.

[0032] Furthermore, to aid in understanding the invention, the accompanying drawings are not shown to actual scale, and the dimensions of some components may be exaggerated. Also, the same component may be assigned the same reference numeral in different embodiments.

[0033] The statement that two comparison objects are "identical" means that they are "substantially identical." Therefore, substantially identical objects may include those with deviations considered low in the industry, for example, deviations of 5% or less. Also, the uniformity of certain parameters within a given domain may mean uniformity in terms of averages.

[0034] For example, terms such as "first," "second," etc., are used to describe various components, but these components are, of course, not limited by these terms. These terms are simply used to distinguish one component from another, and unless otherwise stated, the first component may be the second component.

[0035] Throughout the specification, unless otherwise stated, each component may be singular or plural.

[0036] The placement of any configuration "above (or below)" or "above (or below)" a component means not only that the configuration is placed in contact with the upper (or lower) surface of the component, but also that other configurations may be interposed between the component and any configuration placed on (or below) it.

[0037] Furthermore, when a component is described as being "on," "connected to," or "coupled to" another component, it should be understood that while the components may be directly connected to or linked to each other, other components may be "interposed" between them, or each component may be "connected," "coupled," or "linked" through other components.

[0038] As used herein, the terms “and / or” include any and all combinations of one or more related listed items. Furthermore, when describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” Statements such as “one or more” and “one or more” preceding an element list modify the entire element list, not individual elements of the list.

[0039] Throughout the specification, where "A and / or B" is used, it means A only, B only, or A and B unless otherwise specified, and where "C to D" is used, it means C or greater and D or less unless otherwise specified.

[0040] When syntax such as "at least one of A, B, and C", "at least one of A, B, or C", "at least one selected from the group A, B, and C", and "at least one selected from among A, B, and C" is used to specify a list of elements A, B, and C, the syntax can refer to any and all suitable combinations.

[0041] The term “use” may be considered synonymous with the term “utilize.” As used herein, “substantially,” “about,” and similar terms are used as approximations, not terms of degree, to account for the inherent variability of measured or calculated values ​​as recognized by the general art in question.

[0042] In this specification, terms such as first, second, third, etc., may be used to describe various elements, components, regions, layers, and / or sections, but these elements, components, regions, layers, and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, drawing layer, or section from other elements, components, regions, drawing layers, or sections. Accordingly, the first elements, components, regions, layers, or sections discussed below may be named second elements, components, regions, layers, or sections without departing from the teachings of the exemplary embodiments.

[0043] As illustrated in the drawings, spatial relative terms such as “beneath,” “below,” “lower,” “above,” and “upper” may be used herein for ease of explanation to describe the relationship between one element or feature and other elements or features. Spatially relative positions will be understood to encompass different orientations of the device in use or operation, in addition to the orientation depicted in the figure. For example, if the device in the drawing is turned upside down, an element described as “beneath” or “below” other elements will be understood as “above” or “upper” other elements. Thus, the term “beneath” can encompass both up and down directions.

[0044] The terms used herein are for the purpose of describing the embodiments of this disclosure and are not intended to limit this disclosure.

[0045] Figure 1 is a schematic perspective view showing the configuration of a battery pack according to one embodiment of the present invention.

[0046] Referring to Figure 1, the battery pack according to this embodiment may include a housing 10 and a secondary battery 2.

[0047] The housing 10 forms the general appearance of the battery pack and can provide a space in which the secondary battery 2 can be housed.

[0048] The housing 10 according to this embodiment may include a housing body 11 and a cover 12.

[0049] The housing body 11 can be formed to have the shape of a box with an open interior and one side open. The cross-sectional shape of the housing body 11 is not limited to the rectangle shown in Figure 1, but can be modified to various shapes such as polygons, circles, and ellipses.

[0050] The cover 12 is coupled to the housing body 11 and can close off the internal space of the housing body 11. For example, the cover 12 may be formed to have a substantially plate shape and positioned to face the open side of the housing body 11. The cover 12 can be fixed to the housing body 11 by various types of coupling methods such as bolting, welding, and fitting.

[0051] The secondary battery 2 can function as a unit structure that stores and supplies power in the battery pack. The secondary battery 2 may be located inside the housing 10.

[0052] Multiple secondary batteries 2 may be provided. Multiple secondary batteries 2 may be arranged in two or more rows along at least one direction of the housing 10, either the longitudinal direction (X-axis direction in Figure 1) or the width direction (Y-axis direction in Figure 1). Figure 1 illustrates an example where multiple secondary batteries 2 are arranged in six rows along the longitudinal direction of the housing 10, but the arrangement of multiple secondary batteries 2 is not limited to this, and various configurations can be designed. Multiple secondary batteries 2 may be arranged side by side. The number of secondary batteries 2 can be varied depending on the size and shape of the housing 10.

[0053] Multiple secondary batteries 2 can be electrically connected by busbars 3.

[0054] The busbar 3 in this embodiment may be positioned between the cover 12 and the secondary battery 2. Multiple busbars 3 may be provided. Each busbar 3 can connect adjacent pairs of secondary batteries 2 in series or parallel.

[0055] The busbar 3 can be made of an electrically conductive material such as copper, aluminum, or nickel. The specific shape of the busbar 3 is not limited to that shown in Figure 1, and can be redesigned into a variety of shapes that can electrically connect adjacent secondary batteries 2.

[0056] Multiple busbars 3 can be supported inside the housing 10 by busbar holders H.

[0057] The busbar holder H according to this embodiment may be formed to have a flat plate shape. The busbar holder H may be positioned between the cover 12 and the secondary battery 2. The busbar 3 may be fixed to the busbar holder H by various types of coupling methods such as fitting, bolting, and injection bonding. The busbar holder H may be configured to include an electrically insulating polymer compound material.

[0058] In the following, we will describe secondary batteries 2 according to various embodiments of the present invention.

[0059] Figure 2 is a schematic perspective view showing the configuration of a secondary battery according to one embodiment of the present invention, and Figure 3 is a schematic exploded perspective view showing the configuration of a secondary battery according to one embodiment of the present invention.

[0060] In the following explanation, we will use a lithium-ion secondary battery, specifically a prismatic battery, as an example. However, the present invention is not limited thereto, and the secondary battery may be a lithium polymer battery or a cylindrical battery.

[0061] Referring to Figures 2 and 3, the secondary battery 2 according to this embodiment includes a case 100, an electrode assembly 200, a cap plate 300, terminals 400, and a gasket 500.

[0062] The case 100 forms the general appearance of the secondary battery 2 and can house the electrode assembly 200.

[0063] The case 100 according to this embodiment may include a bottom portion 110, a front portion 120, a rear portion 130, a first side portion 140, and a second side portion 150.

[0064] The bottom portion 110 can form the lower (reference) exterior of the case 100. The bottom portion 110 in this embodiment can have the shape of a rectangular plate. The bottom portion 110 can be placed on the bottom surface of the housing body 11.

[0065] The front portion 120, the rear portion 130, the first side portion 140, and the second side portion 150 can form the external appearance of the circumferential surface of the case 100.

[0066] The front portion 120, rear portion 130, first side portion 140, and second side portion 150 in this embodiment may have the form of plates extending upward (reference in Figure 3) from the edge of the bottom portion 110. The front portion 120, rear portion 130, first side portion 140, and second side portion 150 may be arranged to surround the space above the bottom portion 110. The front portion 120, rear portion 130, first side portion 140, and second side portion 150 may be arranged to form a rectangular cross-sectional shape.

[0067] The front portion 120 and the rear portion 130 may be arranged opposite each other along the longitudinal direction of the housing 10. The front portion 120 and the rear portion 130 may be arranged parallel to each other. The areas of the front portion 120 and the rear portion 130 may be the same as each other.

[0068] The first side portion 140 and the second side portion 150 may be arranged opposite each other along the width direction of the housing 10. The first side portion 140 and the second side portion 150 may be arranged parallel to each other. The areas of the first side portion 140 and the second side portion 150 may be the same as each other. The areas of the first side portion 140 and the second side portion 150 may be smaller than the areas of the front portion 120 and the rear portion 130.

[0069] The case 100 may further include an opening 160. In this embodiment, the opening 160 may represent the space enclosed by the front portion 120, the rear portion 130, the first side portion 140, and the upper ends of the second side portion 150. The opening 160 can connect the internal space and the external space of the case 100.

[0070] Accordingly, the case 100 in this embodiment can have the form of a rectangular hexahedron with an open top.

[0071] The first direction described below is aligned with the Z-axis, with reference to Figures 2 and 3, and may represent the direction from the bottom 110 towards the open section 160. The second direction is aligned with the Y-axis, with reference to Figures 2 and 3, and may represent the direction from the first side section 140 towards the second side section 150. The third direction is aligned with the X-axis, with reference to Figures 2 and 3, and may represent the direction from the front section 120 towards the rear section 130.

[0072] The electrode assembly 200 can function as a unit structure that performs charging and discharging operations in a secondary battery. The electrode assembly 200 can be housed inside the case 100.

[0073] Figure 4 is a schematic diagram showing the configuration of an electrode assembly according to one embodiment of the present invention.

[0074] Referring to Figures 2 to 4, the electrode assembly 200 according to this embodiment may include a first electrode 210, a second electrode 220, and a separation membrane 230 disposed between the first electrode 210 and the second electrode 220. The first electrode 210, the separation membrane 230, and the second electrode 220 may be provided in multiple quantities.

[0075] In the following, we will explain using as an example an electrode assembly 200 having a stack configuration in which multiple first electrodes 210, separation membranes 230, and second electrodes 220 are sequentially stacked along a third direction. However, the electrode assembly 200 is not limited to this configuration, and it is also possible to form it so that the first electrodes 210, separation membranes 230, and second electrodes 220 are stacked and wound along a winding axis in a clockwise or counterclockwise direction.

[0076] The first electrode 210 can function as either the positive or negative electrode of the electrode assembly 200. In the following explanation, we will use the example where the first electrode 210 is the positive electrode of the electrode assembly 200. However, the first electrode 210 is not limited to this and can also function as the negative electrode of the electrode assembly 200.

[0077] The first electrode 210 in this embodiment may be formed in the form of a foil containing a metallic material such as aluminum or an aluminum alloy. The type, size, and shape of the first electrode 210 are not particularly limited, as long as it is conductive without inducing a chemical change in the secondary battery. The cross-sectional shape of the first electrode 210 can be modified to various shapes other than the rectangle shown in Figure 4.

[0078] Multiple first electrodes 210 may be provided. Multiple first electrodes 210 may be arranged along a third direction between the front portion 120 and the rear portion 130 of the case 100. The number of first electrodes 210 can be varied depending on the charging capacity of the secondary battery 2 and other factors.

[0079] At least a part of the first electrode 210 may be coated with a first active material layer 211. The first active material layer 211 may be coated on both sides of the first electrode 210, or, differently, it may also be coated only on one side of the first electrode 210.

[0080] In this embodiment, when the first electrode 210 functions as a positive electrode, the first active material layer 211 can contain a positive electrode active material.

[0081] The positive electrode active material can be a compound (lithiated intercalation compound) capable of reversible intercalation and deintercalation of lithium. More specifically, one or more of composite oxides of metals selected from cobalt, manganese, nickel, iron and combinations thereof and lithium can be used.

[0082] As an example, the positive electrode active material can contain at least any one of lithium-iron-phosphate (LiFePO4, LFP), lithium-manganese-iron-phosphate (LiMnFePO4, LMFP), lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM). Here, 0 < x < 1, 0 < y < 1, 0 < z < 1, and x + y + z = 1 can be satisfied. The positive electrode active material can contain only any one of lithium-iron-phosphate (LiFePO4, LFP), lithium-manganese-iron-phosphate (LiMnFePO4, LMFP), lithium-nickel-cobalt-manganese oxide (LiNixCoyMnzO2, NCM), or it can also contain any two of them, or all of them.

[0083] The first active material layer 211 can further contain a positive electrode conductive material.

[0084] The positive electrode conductive material is used to impart conductivity to the first active material layer 211, and any electronically conductive material that does not cause chemical changes can be used. Examples of positive electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes, metal powders containing copper, nickel, aluminum, silver, etc., metal-based materials in the form of metal fibers, or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0085] The first active material layer 211 may further contain a positive electrode binder.

[0086] The positive electrode binder plays a role in ensuring that the particles constituting the positive electrode active material adhere well to each other, and also in ensuring that the positive electrode active material adheres well to the first electrode 210.

[0087] Examples of positive electrode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0088] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0089] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0090] When using an aqueous binder as the positive electrode binder, it may further contain a cellulose-series compound that can impart viscosity. This cellulose-series compound can be a mixture of one or more carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, or their alkali metal salts. The alkali metal can be Na, K, or Li.

[0091] The dry binder is a polymeric substance that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0092] The first electrode 210 may include a first blank portion 212 to which the first active material layer 211 is not applied. In this embodiment, the first blank portion 212 may be located in the upper end region of the first electrode 210, positioned inside the case 100 toward the opening 160. However, the first blank portion 212 is not limited to this form and can also be formed over the entire edge region of the first electrode 210.

[0093] The second electrode 220 can function as either the positive or negative electrode of the electrode assembly 200, with the remaining one being the other. In the following explanation, we will use the example where the second electrode 220 is the negative electrode of the electrode assembly 200. However, the second electrode 220 is not limited to this and can also function as the positive electrode of the electrode assembly 200.

[0094] Multiple second electrodes 220 may be provided. Multiple second electrodes 220 may be arranged along a third direction between the front portion 120 and the rear portion 130 of the case 100. The first electrode 210 and the second electrode 220 may be arranged alternately along the third direction. The second electrode 220 may be spaced apart from the first electrode 210 at a predetermined interval along the third direction.

[0095] The second electrode 220 in this embodiment may be formed in the form of a foil containing a metallic material such as copper, copper alloy, nickel, or nickel alloy. The type, size, and shape of the second electrode 220 are not particularly limited, as long as it is conductive without inducing a chemical change in the secondary battery. The cross-sectional shape of the first electrode 210 can be redesigned to various shapes other than the rectangle shown in Figure 4.

[0096] A second active material layer 221 may be applied to at least a portion of the second electrode 220. The second active material layer 221 may be applied to both sides of the second electrode 220, or alternatively, to only one side of the second electrode 220.

[0097] Since the second electrode 220 functions as a negative electrode, the second active material layer 221 can contain a negative electrode active material.

[0098] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material that can be doped and dedoped with lithium, or a transition metal oxide.

[0099] As the substance capable of reversibly intercalating / deintercalating the lithium ions, it is a carbon-based negative electrode active material, and for example, it can include crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon include graphite such as amorphous, plate-like, flaky, spherical, fibrous natural graphite, or artificial graphite, and examples of amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, or fired coke, etc.

[0100] As the alloy of the lithium metal, an alloy of lithium and a metal selected from Na, K, Rb, Cs, Fr, Be, Mg, Ca, Sr, Si, Sb, Pb, In, Zn, Ba, Ra, Ge, Al, and Sn can be used.

[0101] As the substance capable of doping and undoping lithium, an 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, SiO x (0 < x < 2), an Si-Q alloy (where Q is selected from alkali metals, alkaline earth metals, group 13 elements, group 14 elements (excluding Si), group 15 elements, group 16 elements, transition metals, rare earth elements, and combinations thereof), or a combination thereof. The Sn-based negative electrode active material can be Sn, SnO2, a Sn-based alloy, or a combination thereof.

[0102] The silicon-carbon composite can be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite can be in a form where amorphous carbon is coated on the surface of silicon particles. For example, it can include secondary particles (cores) assembled from primary silicon particles and an amorphous carbon coating layer (shell) located on the surface of the secondary particles. Amorphous carbon can also be located between the primary silicon particles, and for example, the primary silicon particles can be coated with amorphous carbon. The secondary particles can exist dispersed in an amorphous carbon matrix.

[0103] The silicon-carbon composite may further contain crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles, and an amorphous carbon coating layer located on the surface of this core.

[0104] The aforementioned Si-based or Sn-based anode active material can be used in combination with a carbon-based anode active material.

[0105] The second active material layer 221 may further include a negative electrode conductive material and a negative electrode binder.

[0106] The negative electrode conductive material is used to impart conductivity to the second active material layer 221, and any electronically conductive material that does not cause chemical changes can be used. Examples of negative electrode conductive materials include carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjenblack, carbon fibers, carbon nanofibers, and carbon nanotubes, metal powders containing copper, nickel, aluminum, silver, etc., metal-based materials in the form of metal fibers, or conductive polymers such as polyphenylene derivatives, or mixtures thereof.

[0107] The negative electrode binder plays a role in ensuring that the particles constituting the negative electrode active material adhere well to each other, and also in ensuring that the negative electrode active material adheres well to the second electrode 220.

[0108] Examples of negative electrode binders include non-aqueous binders, aqueous binders, dry binders, or combinations thereof.

[0109] Examples of the non-aqueous binder include polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, ethylene propylene copolymer, polystyrene, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, polyamide-imide, polyimide, or combinations thereof.

[0110] The aqueous binder may be selected from styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, (meth)acrylonitrile-butadiene rubber, (meth)acrylic rubber, butyl rubber, fluororubber, polyethylene oxide, polyvinylpyrrolidone, polyepichlorohydrin, polyphosphazene, poly(meth)acrylonitrile, ethylene propylene diene copolymer, polyvinylpyridine, chlorosulfonated polyethylene, latex, polyester resin, (meth)acrylic resin, phenolic resin, epoxy resin, polyvinyl alcohol, and combinations thereof.

[0111] When using an aqueous binder as the negative electrode binder, it may further contain a cellulose series compound that can impart viscosity. This cellulose series compound can be a mixture of one or more carboxymethylcellulose, hydroxypropylmethylcellulose, methylcellulose, or alkali metal salts thereof. The alkali metal can be Na, K, or Li.

[0112] The dry binder is a polymeric substance that can be formed into fibers, and may be, for example, polytetrafluoroethylene, polyvinylidene fluoride, polyvinylidene fluoride-hexafluoropropylene copolymer, polyethylene oxide, or a combination thereof.

[0113] The second electrode 220 may include a second blank portion 222 to which the second active material layer 221 is not applied. In this embodiment, the second blank portion 222 may be located in the upper end region of the second electrode 220, which is positioned inside the case 100 toward the opening 160. However, the second blank portion 222 is not limited to this form and can also be formed over the entire edge region of the second electrode 220.

[0114] The separation membrane 230 may be placed between the first electrode 210 and the second electrode 220. The separation membrane 230 can perform the function of preventing a short circuit between the first electrode 210 and the second electrode 220 while allowing the movement of lithium ions between them.

[0115] The separation membrane 230 can be positioned to completely surround the surface area of ​​the electrode assembly 200. Accordingly, the separation membrane 230 can prevent the first electrode 210 and the second electrode 220 from being directly exposed to the outside of the electrode assembly 200.

[0116] Such separation membranes 230 may be polyethylene, polypropylene, polyvinylidene fluoride, or multilayer membranes of two or more layers thereof, and mixed multilayer membranes such as polyethylene / polypropylene two-layer separators, polyethylene / polypropylene / polyethylene three-layer separators, and polypropylene / polyethylene / polypropylene three-layer separators may be used.

[0117] The separation membrane 230 may include a porous substrate and a coating layer containing organic, inorganic, or a combination thereof located on one or both sides of the porous substrate.

[0118] The porous substrate may be a polymer film formed from one polymer selected from polyethylene, polyolefins such as polypropylene, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyacetal, polyamide, polyimide, polycarbonate, polyetherketone, polyaryletherketone, polyetherimide, polyamideimide, polybenzimidazole, polyethersulfone, polyphenylene oxide, cyclic olefin copolymer, polyphenylene sulfide, polyethylene naphthalate, glass fiber, Teflon®, and polytetrafluoroethylene, or from a copolymer or mixture of two or more of these polymers.

[0119] The aforementioned organic material may include a polyvinylidene fluoride polymer or a (meth)acrylic polymer.

[0120] The inorganic material may include, but is not limited to, 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.

[0121] The organic and inorganic materials can exist mixed in a single coating layer, or in a form in which a coating layer containing organic materials and a coating layer containing inorganic materials are stacked.

[0122] The electrode assembly 200 according to this embodiment may further include a first tab member 240 and a second tab member 250.

[0123] The first tab member 240 is connected to the first electrode 210 and can protrude to the outside of the electrode assembly 200. By exemplifying the first electrode 210 as the positive electrode, the first tab member 240 can function as the positive electrode tab of the secondary battery 2. However, the first tab member 240 is not limited to this and can function as the negative electrode tab of the secondary battery 2 if the first electrode 210 is the negative electrode.

[0124] The first tab member 240 in this embodiment may extend from the electrode assembly 200 along a first direction. For example, the first tab member 240 may extend inside the case 100 toward the opening 160.

[0125] The first tab member 240 in this embodiment may be provided in multiple units. Multiple first tab members 240 may be spaced apart along a second direction. Figure 3 shows an example where two first tab members 240 are formed, but the number of first tab members 240 is not limited to this, and the design can be modified to various numbers such as three or four.

[0126] The first tab member 240 may include the first tab 241.

[0127] The first tab 241 in this embodiment may have the form of a foil extending along a first direction from the first plain portion 212 of the first electrode 210. The first tab 241 may have a substantially rectangular shape. However, the shape of the first tab 241 is not limited to this, and it can be designed in various forms.

[0128] The first tab 241 may be formed integrally with the first electrode 210. For example, the first tab 241 may be the remaining area of ​​the first plain portion 212 after a portion of the first plain portion 212 has been cut or removed by notching or the like. Alternatively, the first tab 241 may be manufactured separately from the first electrode 210 and then connected to the first plain portion 212 by welding or the like. The material of the first tab 241 may be the same as the material of the first electrode 210.

[0129] The first tab 241 may be provided in multiple units. The number of first tabs 241 may be the same as the number of first electrodes 210. Each first tab 241 may extend individually from the first blank portion 212 of different first electrodes 210. Adjacent first tabs 241 may be arranged facing each other along the third direction. Adjacent first tabs 241 may be arranged parallel to each other. Accordingly, the first tab member 240 according to this embodiment may be an assembly of multiple first tabs 241 stacked along the third direction. Adjacent first tabs 241 may be in contact with each other, or they may be separated by the thickness of the separation film 230.

[0130] The second tab member 250 is connected to the second electrode 220 and can protrude outward from the electrode assembly 200. By exemplifying the second electrode 220 as the negative electrode, the second tab member 250 can function as the negative electrode tab of the secondary battery 2. However, the second tab member 250 is not limited to this and can function as the positive electrode tab of the secondary battery 2 if the second electrode 220 is the positive electrode.

[0131] The second tab member 250 in this embodiment may extend from the electrode assembly 200 along the first direction. That is, the second tab member 250 may extend inside the case 100 toward the opening 160.

[0132] The first tab member 240 and the second tab member 250 may be arranged to be spaced apart along a second direction. For example, the second tab member 250 may be positioned at a predetermined distance from the first tab member 240 along the second direction.

[0133] The second tab member 250 in this embodiment may be provided in multiple units. Multiple second tab members 250 may be spaced apart along the second direction. Figure 3 shows an example where two second tab members 250 are formed, but the number of second tab members 250 is not limited to this, and the design can be modified to various numbers such as three or four.

[0134] The second tab member 250 may include a second tab 251.

[0135] The second tab 251 in this embodiment may have the form of a foil extending along the first direction from the second plain portion 222 of the second electrode 220. The second tab 251 may have a substantially rectangular shape. However, the shape of the second tab 251 is not limited to this, and it can be designed in various forms.

[0136] The second tab 251 may be formed integrally with the second electrode 220. For example, the second tab 251 may be the remaining area of ​​the second plain portion 222 after a portion of the second plain portion 222 has been cut or removed by notching or the like. Alternatively, the second tab 251 may be manufactured separately from the second electrode 220 and then connected to the second plain portion 222 by welding or the like. The material of the second tab 251 may be the same as the material of the second electrode 220.

[0137] The second tab 251 may be provided in multiple units. The number of second tabs 251 may be the same as the number of second electrodes 220. Each second tab 251 may extend individually from the second blank portion 222 of different second electrodes 220. Adjacent second tabs 251 may be arranged facing each other along the third direction. Adjacent second tabs 251 may be arranged parallel to each other. Accordingly, the second tab member 250 according to this embodiment may be an assembly of multiple second tabs 251 stacked along the third direction. Adjacent second tabs 251 may be in contact with each other, or they may be separated by the thickness of the separation film 230.

[0138] The cap plate 300 is attached to the case 100, allowing the case 100 to be sealed.

[0139] The cap plate 300 according to this embodiment may be formed to have the shape of a flat plate. The cap plate 300 may be placed in the opening 160 of the case 100. The cap plate 300 may be placed opposite the electrode assembly 200 along a first direction. That is, the cap plate 300 may be placed at a predetermined distance away from the electrode assembly 200 in a first direction. The cap plate 300 may be placed parallel to the bottom 110 of the case 100.

[0140] The cap plate 300 can be placed on the upper end of the case 100, more specifically, on the upper ends of the front portion 120, the rear portion 130, the first side portion 140, and the second side portion 150. The cap plate 300 can be joined to the case 100 by various types of joining methods such as welding, bolting, and fitting.

[0141] The cap plate 300 may include a first surface 301 and a second surface 302 that are opposite to each other.

[0142] The first surface 301 and the second surface 302 of the cap plate 300 may be positioned to be separated along a first direction. The first surface 301 may be positioned to face the electrode assembly 200.

[0143] The first surface 301 can be exemplified as the lower surface of a cap plate 300, which is positioned to face the upper surface of the electrode assembly 200 from which the first tab member 240 and the second tab member 250 protrude.

[0144] The second surface 302 may be positioned to face the external space of the case 100. The second surface 302 may be exemplified as the upper surface of a cap plate 300 positioned opposite the first surface 301.

[0145] The cap plate 300 according to this embodiment may have vent holes 310 and vents 320 formed therein.

[0146] The vent hole 310 in this embodiment may be formed to have the shape of a hole that penetrates the first surface 301 and the second surface 302 of the cap plate 300 perpendicularly along the first direction. The vent hole 310 can function as a configuration that provides a path for flames, gases, smoke, etc., formed inside the case 100 to be discharged to the outside of the case 100 in the event of thermal runaway of the secondary battery 2 due to overcurrent or the like. The cross-sectional shape of the vent hole 310 can be redesigned to various shapes such as elliptical, circular, and polygonal.

[0147] The vent 320 is installed in the vent hole 310 and can be opened and closed in conjunction with changes in the internal pressure of the case 100. That is, during normal operation of the secondary battery 2, the vent 320 can close the vent hole 310 to prevent electrolyte and other substances from flowing out of the case 100, and prevent moisture, foreign matter, etc. from flowing into the case 100. In the event of thermal runaway of the secondary battery 2, the vent 320 can open the vent hole 310 to guide flames, gases, smoke, etc. formed inside the case 100 to be discharged to the outside of the case 100.

[0148] The vent 320 in this embodiment may be formed to have a substantially plate shape. The vent 320 can be fixed to the cap plate 300 by various types of joining methods such as welding, bolting, and fitting. The vent 320 may also be positioned inside the vent hole 310, or on the upper or lower side of the cap plate 300, facing the vent hole 310 along a first direction.

[0149] The thickness of the vent 320 aligned with the first direction may be less than the thickness of the cap plate 300. Consequently, the vent 320 may easily burst or rupture if the internal pressure of the case 100 increases. The vent 320 may include a notch formed to be recessed on the inside of the vent 320 so that it preferentially ruptures if the internal pressure of the case 100 increases.

[0150] In this embodiment, the cap plate 300 may have an electrolyte inlet 330 formed through the cap plate 300, into which a sealing plug can be installed. The electrolyte inlet 330 may be positioned at a predetermined distance from the vent hole 310 in a second direction or in the opposite direction to the second direction. The electrolyte inlet 330 may be positioned between terminal 400 and second terminal 400.

[0151] In this embodiment, an insulating plate 340 may be placed between the cap plate 300 and the electrode assembly 200. The insulating plate 340 prevents direct contact between the cap plate 300 and the electrode assembly 200, thereby insulating the cap plate 300 from the electrode assembly 200. The insulating plate 340 can fix the position of the electrode assembly 200 inside the case 100. The insulating plate 340 can prevent damage to the electrode assembly 200 if the cap plate 300 is deformed inward into the case 100 due to external impact or the like.

[0152] The insulating plate 340 according to this embodiment may be positioned inside the case 100 so as to face the electrode assembly 200 along a first direction. That is, the electrode assembly 200, the insulating plate 340, and the cap plate 300 may be positioned sequentially along the first direction. The insulating plate 340 may be fixed to the inner surface of the case 100 by various types of bonding methods such as fitting, welding, bolting, and bonding. The insulating plate 340 may be in contact with one surface of the electrode assembly 200 from which the first tab member 240 and the second tab member 250 extend. The insulating plate 340 may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET) rubber.

[0153] Terminal 400 can function as a configuration that provides an electrical connection of the secondary battery 2 to the busbar 3 or an external power device.

[0154] Figure 5 is a schematic perspective view showing the configuration of a terminal and gasket according to one embodiment of the present invention, and Figure 6 is a schematic cross-sectional view showing the configuration of a terminal and gasket according to one embodiment of the present invention.

[0155] Referring to Figures 1 to 6, the terminal 400 in this embodiment may be made of an electrically conductive material such as aluminum, nickel, or copper. The terminal 400 may be inserted into a terminal hole 350 formed through the cap plate 300. The upper end of the terminal 400 may protrude to the outside of the cap plate 300.

[0156] The terminal 400 may include a first terminal surface 401 and a second terminal surface 402 that are opposite to each other. The first terminal surface 401 and the second terminal surface 402 may be spaced apart from each other along a first direction.

[0157] In this embodiment, the first terminal surface 401 may mean the lower surface of the terminal 400 that is positioned toward the electrode assembly 200, and the second terminal surface 402 may mean the upper surface of the terminal 400 that is positioned toward the outside of the cap plate 300.

[0158] The height h of the second terminal surface 402 may be 3 mm. The height h of the second terminal surface 402 may represent the vertical distance from the plane on which the second surface 302 of the cap plate 300 is located to the second terminal surface 402.

[0159] The busbar 3 can be placed on the second terminal surface 402. The busbar 3 and the second terminal surface 402 can be joined together by laser welding or the like.

[0160] Figures 5 and 6 illustrate an example where the terminal 400 has a rectangular cross-sectional shape. However, the cross-sectional shape of the terminal 400 is not limited to this, and it can be redesigned to various shapes such as circular, elliptical, or polygonal.

[0161] The terminals 400 may be provided in pairs. The pair of terminals 400 may be arranged to be spaced apart at a predetermined interval along the second direction. The pair of terminals 400 may be arranged to face each other along the second direction with the vent hole 310 in between.

[0162] Of the pair of terminals 400, one terminal 400 may be positioned to face the first tab member 240 along the first direction, and the other terminal 400 may be positioned to face the second tab member 250 along the first direction.

[0163] The pair of terminals 400 can be individually connected to the first electrode 210 and the second electrode 220 of the electrode assembly 200, respectively. Accordingly, the pair of terminals 400 can function as the positive and negative terminals of the secondary battery 2, respectively.

[0164] The pair of terminals 400 can be electrically connected to the first electrode 210 and the second electrode 220 by a first connecting member 410 and a second connecting member 420, respectively.

[0165] The first connecting member 410 may be positioned between the electrode assembly 200 and the cap plate 300. The first connecting member 410 can connect the terminal 400 of the pair of terminals 400 that is positioned opposite the first tab member 240 to the first tab member 240. The first connecting member 410 may be made of an electrically conductive material. The first connecting member 410 may be made of the same material as the terminal 400.

[0166] The first connecting member 410 according to this embodiment may include a first current collector 411 and a first current collector plate 412.

[0167] The first current collector 411 can be connected to one of the pair of terminals 400, which is positioned opposite the first tab member 240.

[0168] The first current collector 411 according to this embodiment may include a first body 411a and a first boss 411b.

[0169] The first body 411a forms the outer surface of one side of the first current collector 411 and can support the first boss 411b.

[0170] The first body 411a according to this embodiment may be positioned between the first tab member 240 and the terminal 400. The first body 411a may be positioned at a predetermined distance along the first direction from the lower surface of the terminal 400, which is positioned opposite the first tab member 240. The first body 411a may be positioned inside the insulating plate 340, or alternatively, above or below the insulating plate 340. The cross-sectional shape of the first body 411a can be modified to various shapes other than the rectangle shown in the drawing, such as circles, ellipses, and polygons.

[0171] The first boss 411b may be connected to a terminal 400 that extends from the first body 411a and is positioned opposite the first tab member 240.

[0172] The first boss 411b in this embodiment may have a cylindrical shape extending from the first body 411a along a first direction. The upper end surface of the first boss 411b may contact the lower surface of the terminal 400, which is positioned opposite the first tab member 240. In this case, the first boss 411b can penetrate the insulating plate 340 perpendicularly along the first direction. The cross-sectional shape of the first boss 411b can be modified to various shapes other than the circular shape shown in the drawing, such as an ellipse or polygon. The upper end surface of the first boss 411b may be joined to the lower surface of the terminal 400 by laser welding.

[0173] The first current collector plate 412 can be fixed to the first current collector 411 and connected to the first tab member 240.

[0174] The first current collector plate 412 according to this embodiment may include a first center plate 412a and a first extension plate 412b.

[0175] The first center plate 412a forms the central part of the first current collector plate 412 and can be connected to the first current collector 411.

[0176] The first center plate 412a according to this embodiment may be positioned between the first body 411a and the electrode assembly 200. The first center plate 412a may be in contact with the lower surface of the first body 411a located opposite the first boss 411b. The first center plate 412a may be fixed to the lower surface of the first body 411a by various types of bonding methods such as welding, bolting, and bonding.

[0177] The first center plate 412a may have both ends extending from the first body 411a toward the electrode assembly 200. Both ends of the first center plate 412a may penetrate the insulating plate 340 and be positioned beneath the insulating plate 340.

[0178] The first extension plate 412b extends and can come into contact with the first tab member 240.

[0179] The first extension plates 412b in this embodiment may be provided in pairs. The pair of first extension plates 412b may extend from both ends of the first center plate 412a along a second direction and a direction opposite to the second direction. Each first extension plate 412b may be positioned opposite each other along the first direction to different first tab members 240. Each first extension plate 412b may individually contact the end faces of different first tab members 240. The first tab members 240 and the first extension plates 412b may be joined to each other by laser welding.

[0180] The second connecting member 420 may be positioned between the electrode assembly 200 and the cap plate 300. The second connecting member 420 can connect the terminal 400 of the pair of terminals 400 that is positioned opposite the second tab member 250 to the second tab member 250. The second connecting member 420 may be made of an electrically conductive material. The second connecting member 420 may be made of the same material as the terminal 400.

[0181] The second connecting member 420 according to this embodiment may include a second current collector 421 and a second current collector plate 422.

[0182] The second current collector 421 can be connected to the terminal 400 of the pair of terminals 400 that is positioned opposite the second tab member 250.

[0183] The second current collector 421 according to this embodiment may include a second body 421a and a second boss 421b.

[0184] The second body 421a forms one side of the exterior of the second current collector 421 and can support the second boss 421b.

[0185] The second body 421a according to this embodiment may be positioned between the second tab member 250 and the terminal 400. The second body 421a may be positioned at a predetermined distance along the first direction from the lower surface of the terminal 400, which is positioned opposite the second tab member 250. The second body 421a may be positioned inside the insulating plate 340, or alternatively, it may be positioned above or below the insulating plate 340. The cross-sectional shape of the second body 421a can be modified to various shapes other than the rectangle shown in the drawing, such as circles, ellipses, and polygons.

[0186] The second boss 421b may be connected to a terminal 400 that extends from the second body 421a and is positioned opposite the second tab member 250.

[0187] The second boss 421b in this embodiment may have a cylindrical shape extending from the second body 421a along the first direction. The upper end surface of the second boss 421b may contact the lower surface of the terminal 400, which is positioned opposite the second tab member 250. In this case, the second boss 421b can penetrate the insulating plate 340 perpendicularly along the first direction. The cross-sectional shape of the second boss 421b can be modified to various shapes other than the circular shape shown in the drawing, such as an ellipse or polygon. The upper end surface of the second boss 421b may be joined to the lower surface of the terminal 400 by laser welding.

[0188] The second current collector plate 422 can be fixed to the second current collector 421 and connected to the second tab member 250.

[0189] The second current collector plate 422 according to this embodiment may include a second center plate 422a and a second extension plate 422b.

[0190] The second center plate 422a forms the central part of the second current collector plate 422 and can be connected to the second current collector 421.

[0191] The second center plate 422a according to this embodiment may be positioned between the second body 421a and the electrode assembly 200. The second center plate 422a may be in contact with the lower surface of the second body 421a located on the opposite side of the second boss 421b. The second center plate 422a may be fixed to the lower surface of the second body 421a by various types of bonding methods such as welding, bolting, and bonding.

[0192] The second center plate 422a may have both ends extending from the second body 421a toward the electrode assembly 200. Both ends of the second center plate 422a may penetrate the insulating plate 340 and be positioned beneath the insulating plate 340.

[0193] The second extension plate 422b can extend and come into contact with the second tab member 250.

[0194] The second extension plates 422b in this embodiment may be provided in pairs. The pair of second extension plates 422b may extend from both ends of the second center plate 422a along the second direction and the opposite direction to the second direction. Each second extension plate 422b may be positioned opposite each other along the first direction to different second tab members 250. Each second extension plate 422b may individually contact the end faces of different second tab members 250. The second tab members 250 and the second extension plates 422b may be joined to each other by laser welding.

[0195] The gasket 500 may be placed between the cap plate 300 and the terminal 400. The gasket 500 can function as a component for electrically insulating the cap plate 300 and the terminal 400 from each other. The gasket 500 may be formed from an insulating material such as polyethylene (PE), polypropylene (PP), or polyethylene terephthalate (PET) rubber.

[0196] The gaskets 500 may be provided in pairs. Of the pair of gaskets 500, one gasket 500 may be placed between the terminal 400 connected to the first connecting member 410 and the cap plate 300. Of the pair of gaskets 500, the other gasket 500 may be placed between the terminal 400 connected to the second connecting member 420 and the cap plate 300.

[0197] Figure 7 is an enlarged schematic view showing the configuration of a gasket according to one embodiment of the present invention.

[0198] In the following explanation, we will use as an example the gasket 500 of the pair of gaskets 500, which is positioned between the terminal 400 connected to the first connecting member 410 and the cap plate 300. The following explanation of gasket 500 can also be applied identically to the gasket 500 positioned between the terminal 400 connected to the second connecting member 420 and the cap plate 300.

[0199] Referring to Figure 7, the gasket 500 according to this embodiment may be placed inside the terminal hole 350. The gasket 500 may include a first end 501 and a second end 502.

[0200] The first end 501 and the second end 502 can be exemplified as portions of the entire gasket 500 that come into contact with the cap plate 300 and the terminal 400, respectively.

[0201] The first end portion 501 in this embodiment may be the outer circumferential surface of the gasket 500 that contacts the inner circumferential surface of the cap plate 300, which is positioned to surround the terminal hole 350. The first end portion 501 may extend along the inner circumferential surface of the cap plate 300.

[0202] The second end portion 502 in this embodiment may be the inner circumferential surface of the gasket 500 that contacts the outer circumferential surface of the terminal 400. The second end portion 502 may be positioned to completely surround the outer circumferential surface of the terminal 400.

[0203] The creepage distance of the gasket 500 in this embodiment may be greater than the distance L0 between the first end 501 and the second end 502. Here, the creepage distance of the gasket 500 can be exemplified as the shortest distance connecting the first end 501 and the second end 502 along the surface of the gasket 500 exposed to the outside of the cap plate 300 (the top surface in reference to Figure 7). Accordingly, the gasket 500 can maintain insulation between the cap plate 300 and the terminal 400 more stably.

[0204] The creepage distance of the gasket 500 may be between 6 mm and 10 mm. In this embodiment, the creepage distance of the gasket 500 may be 8.7 mm. If the creepage distance of the gasket 500 is less than 6 mm, sufficient insulation between the cap plate 300 and the terminal 400 may not be ensured. If the creepage distance of the gasket 500 is greater than 10 mm, the shape of the gasket 500 may not be maintained consistently during injection molding.

[0205] The gasket 500 according to this embodiment may include a first insulating surface 510, a second insulating surface 520, and a third insulating surface 530.

[0206] The first insulating surface 510, the second insulating surface 520, and the third insulating surface 530 can form the appearance of the surface of the gasket 500 that is exposed to the outside of the cap plate 300.

[0207] In this embodiment, the first insulating surface 510 may extend from the first end 501 toward the terminal 400. The first insulating surface 510 may be arranged parallel to the second surface 302 of the cap plate 300. The first insulating surface 510 may be arranged on the same plane as the second surface 302 of the cap plate 300. That is, the first insulating surface 510 and the second surface 302 of the cap plate 300 may be arranged to form a continuous plane.

[0208] The second insulating surface 520 in this embodiment may be spaced apart from the first insulating surface 510 and may extend from the second end 502 toward the cap plate 300. The first insulating surface 510 may be positioned parallel to the second surface 302 of the cap plate 300. The second insulating surface 520 may be positioned on a plane other than the first insulating surface 510. As an example, the second insulating surface 520 may be positioned higher than the first insulating surface 510 and the second surface 302. That is, the distance from the electrode assembly 200 to the second insulating surface 520 may be greater than the distance from the electrode assembly 200 to the first insulating surface 510. The gasket 500 may be formed to be relatively taller on the side of the second end 502 that is in contact with the terminal 400 than on the side of the first end 501 that is in contact with the cap plate 300. Consequently, the gasket 500 can more firmly support the terminal 400 inside the terminal hole 350.

[0209] The third insulating surface 530 in this embodiment may be positioned between the first insulating surface 510 and the second insulating surface 520. The third insulating surface 530 may be positioned so as to intersect with the second surface 302 of the cap plate 300. For example, the third insulating surface 530 may be positioned perpendicular to the second surface 302 of the cap plate 300. The lower end of the third insulating surface 530 may be connected to the inner end of the first insulating surface 510 located opposite the first end 501. The upper end of the third insulating surface 530 may be connected to the outer end of the second insulating surface 520 located opposite the second end 502.

[0210] In this embodiment, the creepage distance of the gasket 500 may be the sum of the creepage distance L1 of the first insulating surface 510, the creepage distance L2 of the second insulating surface 520, and the creepage distance L3 of the third insulating surface 530.

[0211] The creepage distance L1 of the first insulating surface 510 may be the shortest distance from the first end 501 to the lower end of the third insulating surface 530, the creepage distance L2 of the second insulating surface 520 may be the shortest distance from the second end 502 to the upper end of the third insulating surface 530, and the creepage distance L3 of the third insulating surface 530 may be the distance from the lower end to the upper end of the third insulating surface 530.

[0212] The creepage distance L1 of the first insulating surface 510 may be 3 mm or more and 5 mm or less. For example, the creepage distance L1 of the first insulating surface 510 may be 4.2 mm.

[0213] The creepage distance L2 of the second insulating surface 520 may be smaller than the creepage distance L1 of the first insulating surface 510. The creepage distance of the second insulating surface 520 may be between 1 mm and 4 mm. The creepage distance of the second insulating surface 520 may be 3 mm. If the creepage distance of the second insulating surface 520 is less than 1 mm, the width of the inner region of the gasket 500 that contacts the terminal 400 may be excessively reduced, and the support force of the gasket 500 on the terminal 400 may be weakened. If the creepage distance of the second insulating surface 520 is less than 3 mm, the injection of the gasket 500 may not be smooth.

[0214] The creepage distance L3 of the third insulating surface 530 may be between 1 mm and 3 mm. If the creepage distance L3 of the third insulating surface 530 is less than 1 mm, the increase in the ratio of the distance L0 between the first end 501 and the second end 502 to the creepage distance of the gasket 500 may decrease excessively, and the insulation performance between the cap plate 300 and the terminal 400 may not be sufficiently ensured. If the creepage distance L3 of the third insulating surface 530 is greater than 3 mm, the second insulating surface 520 may protrude above the second terminal surface 402 and interfere with the busbar 3.

[0215] The gasket 500 according to this embodiment may further include a support surface 540 that is separated from the first insulating surface 510 and faces the electrode assembly 200.

[0216] The support surface 540 in this embodiment may be exemplified as the lower surface of a gasket 500 located opposite the first insulating surface 510, the second insulating surface 520, and the third insulating surface 530, and positioned toward the internal space of the case 100. The support surface 540 may be positioned parallel to the first insulating surface 510 and the second insulating surface 520. The support surface 540 and the first insulating surface 510 and the second insulating surface 520 may be positioned opposite each other along the first direction.

[0217] The cross-sectional area of ​​the gasket 500 may increase from the support surface 540 toward the first insulating surface 510. The first end 501 may have the form of an inclined surface, with both ends connected to the outer ends of the support surface 540 and the first insulating surface 510, respectively, and arranged to be inclined with respect to the first direction. Accordingly, the gasket 500 according to this embodiment can further increase the creepage distance L1 of the first insulating surface 510.

[0218] The secondary battery 2 according to this embodiment may further include ribs 600.

[0219] The rib 600 protrudes from the cap plate 300 and can support the support surface 540. The rib 600 can function as a configuration that supports the gasket 500 inside the terminal hole 350.

[0220] In this embodiment, the rib 600 can extend from the inner circumferential surface of the cap plate 300 surrounding the terminal hole 350 toward the terminal hole 350. The rib 600 can have the form of a rectangular plate that divides the terminal hole 350 vertically.

[0221] The ribs 600 may be provided in pairs. Each rib 600 may extend individually from the inner surface of the cap plate 300 surrounding different terminal holes 350.

[0222] The support surface 540 can be placed on the upper surface of the rib 600 inside the terminal hole 350. Accordingly, the rib 600 can prevent the gasket 500 from detaching into the inside of the case 100.

[0223] In this embodiment, a first rib hole 610 and a second rib hole 620 may be formed in the rib 600.

[0224] The first rib hole 610 may have the form of a hole that penetrates the central part of the rib 600 along the first direction. The cross-sectional area of ​​the first rib hole 610 may be larger than the cross-sectional areas of the first boss 411b and the second boss 421b. The first boss 411b or the second boss 421b may penetrate the first rib hole 610 and contact the first terminal surface 401 of the terminal 400.

[0225] The second rib hole 620 may penetrate the rib 600 along the first direction and be spaced apart from the first rib hole 610. The second rib hole 620 may be positioned at a predetermined distance apart along the radial direction of the first rib hole 610. Multiple second rib holes 620 may be provided. Multiple second rib holes 620 may be arranged along the circumferential direction with respect to the central axis of the first rib hole 610.

[0226] The gasket 500 according to this embodiment may further include a fixing portion 550.

[0227] The fixing portion 550 may extend from the support surface 540 and be positioned to surround the rib 600. Accordingly, the fixing portion 550 can strengthen the bonding force between the gasket 500 and the rib 600.

[0228] The fixing portion 550 in this embodiment may extend downward from the support surface 540, that is, in the opposite direction to the first direction. The fixing portion 550 may penetrate the first rib hole 610 and the second rib hole 620 and protrude below the rib 600. The end of the fixing portion 550 may be bent toward the lower surface of the rib 600 and contact and fix to the lower surface of the rib 600. Accordingly, the fixing portion 550 can form a locking force between the gasket 500 and the rib 600, thereby strengthening the bonding force between the gasket 500 and the rib 600.

[0229] The following describes a secondary battery 2 according to another embodiment of the present invention.

[0230] The secondary battery 2 according to this embodiment can be configured to differ only from the secondary battery 2 according to one embodiment of the present invention described with reference to Figures 1 to 7, except for the detailed configuration of the gasket 500.

[0231] Accordingly, in describing the secondary battery 2 according to this embodiment, we will only describe the detailed configuration of the gasket 500 that differs from the secondary battery 2 according to one embodiment of the present invention.

[0232] The remaining components of the secondary battery 2 according to this embodiment can be described in the same way as the description of the secondary battery 2 according to one embodiment of the present invention.

[0233] Figure 8 is a schematic perspective view showing the configuration of a gasket according to another embodiment of the present invention, and Figure 9 is a schematic cross-sectional view showing the configuration of a gasket according to another embodiment of the present invention.

[0234] Referring to Figures 8 and 9, the gasket 500 according to this embodiment may further include grooves 560.

[0235] The groove 560 may be formed to be recessed from at least one of the first insulating surface 510, the second insulating surface 520, and the third insulating surface 530. Accordingly, the secondary battery 2 according to this embodiment can further improve the insulating performance of the gasket 500 by increasing the creepage distance of the gasket 500 exposed to the outside of the cap plate 300 by the length of the inner circumferential surface of the groove 560.

[0236] Figure 10 is an enlarged view schematically showing the groove configuration according to this embodiment.

[0237] Referring to Figures 8 to 10, the groove 560 in this embodiment can have the form of a groove that is recessed from the first insulating surface 510 toward the support surface 540. The depth of the groove 560 can be varied in design within a range smaller than the distance between the first insulating surface 510 and the support surface 540. For example, the depth of the groove 560 may be 1.2 mm.

[0238] The groove 560 may be formed to surround the circumferential surface of the terminal 400. For example, the groove 560 may be extended to continuously surround the circumferential surface of the terminal 400, centered on the terminal 400. In this case, the groove 560 can increase the creepage distance of the gasket 500 over the entire area around the terminal 400.

[0239] The above description has taken as an example in which the groove 560 is formed recessed inward of the first insulating surface 510, but the present invention is not limited thereto, and it is also possible for the groove 560 to be formed on the second insulating surface 520, or the third insulating surface 530, or any two of the first insulating surface 510, the second insulating surface 520 and the third insulating surface 530, or on all of the first insulating surface 510, the second insulating surface 520 and the third insulating surface 530.

[0240] The following describes a secondary battery 2 according to yet another embodiment of the present invention.

[0241] The secondary battery 2 according to this embodiment can be configured to differ only in the detailed configuration of the gasket 500 from the secondary battery 2 according to one embodiment of the present invention described with reference to Figures 1 to 7, and the secondary battery 2 according to another embodiment of the present invention described with reference to Figures 8 to 10.

[0242] Accordingly, in describing the secondary battery 2 according to this embodiment, we will only describe the detailed configuration of the gasket 500 that differs from the secondary battery 2 according to the previously described embodiment.

[0243] The remaining components of the secondary battery 2 according to this embodiment can be directly described in the above-mentioned explanation of the secondary battery 2 according to the embodiment of the present invention.

[0244] Figure 11 is a schematic perspective view showing the configuration of a gasket according to yet another embodiment of the present invention, and Figure 12 is a schematic cross-sectional view showing the configuration of a gasket according to yet another embodiment of the present invention.

[0245] Figures 11 and 12 illustrate an example of the gasket 500 according to this embodiment that does not include grooves 560. However, the gasket 500 according to this embodiment is not limited to this example, and can also be configured to include grooves 560.

[0246] Referring to Figures 11 and 12, the gasket 500 according to this embodiment may further include a filler 570.

[0247] The filler 570 may protrude from at least one of the first insulating surface 510, the second insulating surface 520, and the third insulating surface 530. Accordingly, the secondary battery 2 according to this embodiment can further improve the insulating performance of the gasket 500 by increasing the creepage distance of the gasket 500 exposed to the outside of the cap plate 300 by the length of the inner circumferential surface of the filler 570.

[0248] Figure 13 is an enlarged view schematically showing the configuration of the filler according to this embodiment.

[0249] Referring to Figures 11 to 13, the filler 570 according to this embodiment can have the form of a column protruding from the second insulating surface 520 along the first direction.

[0250] The end of the filler 570 may be positioned lower than the second terminal surface 402 of the terminal 400. This prevents the filler 570 from interfering with the busbar 3 which rests on the second terminal surface 402. For example, the height of the filler 570 may be 1 mm.

[0251] The filler 570 may be formed to surround the circumferential surface of the terminal 400. For example, the filler 570 may be extended to continuously surround the circumferential surface of the terminal 400, centered on the terminal 400. In this case, the filler 570 can increase the creepage distance of the gasket 500 over the entire circumference of the terminal 400.

[0252] The above description has used as an example a case in which the filler 570 protrudes from the second insulating surface 520, but the present invention is not limited thereto, and it is also possible for the filler 570 to be formed on the first insulating surface 510 or the third insulating surface 530, any two of the first insulating surface 510, the second insulating surface 520 and the third insulating surface 530, or on all of the first insulating surface 510, the second insulating surface 520 and the third insulating surface 530.

[0253] Although the present invention has been described with reference to the embodiments illustrated in the drawings, these are merely illustrative, and a person with ordinary skill in the art will understand that a variety of modifications and equivalent other embodiments are possible therefrom.

[0254] Therefore, the scope of technical protection of the present invention should be defined by the following claims. [Explanation of Symbols]

[0255] 2: Secondary battery 3: Bus bar 10: Housing 11: Housing Body 12: Cover 100: Case 110: Bottom 120: Front part 130: Rear part 140: First side section 150: Second side section 160:Open part 200: Electrode assembly 210: First electrode 211: First active material layer 212: First blank section 220: Second electrode 221: Second active material layer 222: Second plain section 230: Separation membrane 240: First tab member 241: First tab 250: Second tab member 251: Second tab 300: Cap plate 301: First side 302: The second side 310: Venthole 320: Vent 330: Electrolyte inlet 340: Insulating plate 350: Terminal Hole 400: Terminal 401: First terminal surface 402: Second terminal surface 410: First connecting member 411: First current collector 411a: First body 411b: First Boss 412: First current collection plate 412a: First center plate 412b: First extension plate 420: Second connecting member 421: Second current collector 421a: Second body 421b: Second boss 422: Second current collection plate 422a: Second center plate 422b: Second extension plate 500: Gasket 501: First end 502: Second end 510: First insulating surface 520: Second insulating surface 530: Third insulating surface 540: Support surface 550:Fixed part 560: Groove 570: Filler 600: Rib 610: First rib hole 620: Second Rib Hole

Claims

1. The case and, An electrode assembly is placed inside the aforementioned case, A cap plate having a first surface facing the electrode assembly and a second surface opposite to the first surface, A terminal protruding from the outside of the cap plate and connected to the electrode assembly, The gasket is positioned between the cap plate and the terminal and has a first end that contacts the cap plate and a second end that contacts the terminal, A secondary battery characterized in that the creepage distance of the gasket is greater than the distance between the first end and the second end.

2. The aforementioned gasket is A first insulating surface extending from the first end toward the terminal, A second insulating surface extending from the second end toward the cap plate and separated from the first insulating surface, The secondary battery according to claim 1, further comprising a third insulating surface disposed between the first insulating surface and the second insulating surface.

3. The secondary battery according to claim 2, characterized in that the first insulating surface and the second insulating surface are arranged parallel to the second surface.

4. The secondary battery according to claim 2, characterized in that the first insulating surface and the second insulating surface are arranged on different planes.

5. The secondary battery according to claim 4, characterized in that the second insulating surface is positioned higher than the first insulating surface.

6. The secondary battery according to claim 2, characterized in that the first insulating surface is arranged on the same plane as the second surface.

7. The secondary battery according to claim 2, characterized in that the third insulating surface is arranged to intersect with the second surface.

8. The secondary battery according to claim 2, characterized in that the creepage distance of the gasket is the sum of the creepage distance of the first insulating surface, the creepage distance of the second insulating surface, and the creepage distance of the third insulating surface.

9. The secondary battery according to claim 8, characterized in that the creepage distance of the gasket is 6 mm or more and 10 mm or less.

10. The secondary battery according to claim 8, characterized in that the creepage distance of the second insulating surface is smaller than the creepage distance of the first insulating surface.

11. The secondary battery according to claim 8, characterized in that the creepage distance of the second insulating surface is 1 mm or more and 4 mm or less.

12. The secondary battery according to claim 8, characterized in that the creepage distance of the third insulating surface is 1 mm or more and 3 mm or less.

13. The secondary battery according to claim 2, characterized in that the gasket further includes a support surface that is separated from the first insulating surface and faces the electrode assembly.

14. The secondary battery according to claim 13, characterized in that the cross-sectional area of ​​the gasket increases from the support surface toward the first insulating surface.

15. The secondary battery according to claim 13, further comprising ribs that protrude from the cap plate and support the support surface.

16. The secondary battery according to claim 15, characterized in that the gasket further includes a fixing portion extending from the support surface and arranged to surround the rib.

17. The secondary battery according to claim 2, wherein the gasket further includes grooves formed to be recessed from at least one of the first insulating surface, the second insulating surface, and the third insulating surface.

18. The secondary battery according to claim 2, characterized in that the gasket further includes a filler protruding from any one of the first insulating surface, the second insulating surface, and the third insulating surface.

19. The terminal includes a first terminal surface facing the electrode assembly and a second terminal surface opposite to the first terminal surface. The secondary battery according to claim 18, characterized in that the end of the filler is positioned lower than the second terminal surface.

20. Housing and The housing includes a plurality of secondary batteries arranged inside the housing, The aforementioned secondary battery is The case and, An electrode assembly is placed inside the aforementioned case, A cap plate having a first surface facing the electrode assembly and a second surface opposite to the first surface, A terminal that penetrates the aforementioned cap plate and is connected to the electrode assembly, The gasket is positioned between the cap plate and the terminal and has a first end that contacts the cap plate and a second end that contacts the terminal, A battery pack characterized in that the creepage distance of the gasket is greater than the distance between the first end and the second end.

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