Secondary battery

Abstract

A secondary battery according to an embodiment of the present disclosure includes: a case including a terminal hole penetrating a top surface of the case; an electrode assembly accommodated in the case; a terminal portion inserted into the terminal hole; and a sealing member extending from the inside of the housing to between the housing and the terminal portion, and provided between the housing and the terminal portion.

Description

Technical Field

[0001] The disclosure of this application relates to a secondary battery. Background Technology

[0002] Rechargeable batteries are batteries that can be repeatedly charged and discharged. With the development of the information communication and display industries, they are widely used as power sources for portable electronic communication devices such as cameras, mobile phones, and laptops. Furthermore, battery packs incorporating rechargeable batteries are currently being developed and applied as power sources for environmentally friendly vehicles such as electric vehicles.

[0003] A secondary battery can be defined by housing the electrode assembly within a casing. For example, a secondary battery can be assembled by inserting the electrode assembly through an opening in the casing and then sealing the opening.

[0004] The opening can be sealed by a cap assembly including a cap plate. For example, an insulator and a gasket can be inserted inside the cap assembly, and a pressure seal can be achieved by rivets.

[0005] However, the seal may damage the secondary battery or cause poor assembly, thus creating a leakage path for electrolyte or gas and reducing the life of the secondary battery. Summary of the Invention

[0006] (a) Technical problems to be solved

[0007] According to one aspect of this disclosure, a secondary battery with improved structural stability and reliability can be provided.

[0008] (II) Technical Solution

[0009] A secondary battery according to an exemplary embodiment of the present disclosure includes: a housing including a terminal hole extending through a top surface of the housing; an electrode assembly housed within the housing; a terminal portion inserted into the terminal hole; and a sealing member extending from the interior of the housing between the housing and the terminal portion, and disposed between the housing and the terminal portion.

[0010] In some embodiments, the sealing member may extend along the inner surface of the housing, the side of the terminal hole, and the top surface of the housing.

[0011] In some embodiments, the terminal portion may include an exposed portion disposed on the top surface of the housing and an insertion portion inserted into the terminal hole.

[0012] In some embodiments, the sealing member may extend along the inner surface of the housing and the side of the insertion portion.

[0013] In some embodiments, the diameter of the exposed portion is the same as the diameter of the inserted portion, and the sealing member may extend further along the side of the exposed portion.

[0014] In some embodiments, the diameter of the exposed portion is larger than the diameter of the inserted portion, and the sealing member may extend further along the top surface of the housing.

[0015] In some embodiments, the diameter of the exposed portion is larger than the diameter of the inserted portion, and the sealing member may extend further along the top surface of the housing and the side surface of the exposed portion.

[0016] In some embodiments, when the sealing member is viewed in a planar direction, the length of the exposed portion protruding outward can be from 1 mm to 3 mm.

[0017] In some embodiments, the sealing member may completely cover the side of the terminal portion.

[0018] In some embodiments, the sealing member can insulate the electrode assembly and the top surface of the housing.

[0019] In some embodiments, at least a portion of the sealing member may be exposed on the top surface of the housing.

[0020] In some embodiments, the sealing component may comprise a polymer.

[0021] In some embodiments, the sealing component may comprise at least one selected from high-density polyethylene, perfluoroalkoxy, silicone, and polybutylene terephthalate.

[0022] In some embodiments, the sealing component may be formed on the terminal portion by insert injection molding.

[0023] In some embodiments, the housing may include an opening opposite the top surface.

[0024] In some embodiments, the secondary battery may further include a cover plate disposed in the opening and combined with the housing.

[0025] (III) Beneficial Effects

[0026] According to one embodiment of this disclosure, the structural stability of a secondary battery can be improved.

[0027] According to one embodiment of this disclosure, the driving reliability of a secondary battery can be improved.

[0028] The secondary battery disclosed herein can be widely used in electric vehicles, battery charging stations, and other green technology fields such as solar power generation and wind power generation that utilize batteries. Furthermore, the secondary battery disclosed herein can be used in eco-friendly electric vehicles and hybrid vehicles that mitigate climate change by reducing air pollution and greenhouse gas emissions. Attached Figure Description

[0029] Figure 1 This is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment.

[0030] Figure 2 This is a schematic perspective view of a secondary battery according to an exemplary embodiment.

[0031] Figures 3 to 5 This is a schematic cross-sectional view of a secondary battery according to an exemplary embodiment.

[0032] Figure 6 This is a schematic plan view taken from the top surface of a secondary battery according to an exemplary embodiment.

[0033] Figures 7 to 9 This is a schematic perspective view illustrating a method for manufacturing a sealing component included in a secondary battery according to an exemplary embodiment.

[0034] Explanation of reference numerals in the attached figures:

[0035] 100: Casing 110: Opening

[0036] 120: Terminal hole; 130: Terminal section

[0037] 132: Exposed part; 134: Insertion part

[0038] 136: Head; 140: Sealing component

[0039] 10: First injection mold; 15: Groove

[0040] 20: Second injection mold; 25: Recess.

[0041] 140a: Pre-injection molded part; 200: Electrode assembly

[0042] 210: Positive electrode; 212: Positive electrode current collector

[0043] 214: Positive electrode active material layer; 215: Positive electrode tab.

[0044] 217: Positive lead; 220: Negative lead

[0045] 222: Negative electrode current collector; 224: Negative electrode active material layer

[0046] 225: Negative electrode tab; 227: Negative electrode lead.

[0047] 230: Diaphragm; 300: Cover plate Detailed Implementation

[0048] Embodiments of this disclosure provide a secondary battery.

[0049] The embodiments of this disclosure will now be described in detail. However, these are merely examples, and this disclosure is not limited to the specific implementations described herein.

[0050] The terms “top surface,” “bottom surface,” “side surface,” “inner surface,” and “outer surface” used in this specification are used in a relative sense to distinguish the position of components and do not specify absolute positions.

[0051] Figure 1 This is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment. Figure 2 This is a schematic perspective view of a secondary battery according to an exemplary embodiment.

[0052] Reference Figure 1 and Figure 2 The secondary battery may include a housing 100 having a terminal hole 120 penetrating the top surface, an electrode assembly 200 housed within the housing 100, a terminal portion 130 inserted into the terminal hole 120, and a sealing member 140 disposed between the housing 100 and the terminal portion 130.

[0053] The housing 100 may be provided as at least a portion of the outer surface of the secondary battery. In one embodiment, the housing 100 may comprise metal. Therefore, impact on the electrode assembly 200 can be mitigated.

[0054] In some embodiments, the housing 100 may include an opening 110 opposite to the top surface. The secondary battery may further include a cover 300 disposed in the opening 110 and coupled to the housing 100.

[0055] For example, cover plate 300 can be provided as a bottom cover for a secondary battery. For example, cover plate 300 may include a cover having a plate shape and a hole penetrating the cover. Electrolyte can be injected or gases generated inside the secondary battery can be vented through the hole.

[0056] In some embodiments, the cover plate 300 may further include an auxiliary terminal portion for insertion into the hole.

[0057] The composition / structure of the cover plate 300 is not limited to the above-mentioned contents. Any cover or cover plate structure known in the field of secondary batteries can be used without restriction.

[0058] For example, secondary batteries can be manufactured in cylindrical, prismatic, pouch, or coin shapes, similar to cans. Various forms of secondary batteries can be manufactured based on the shapes of the casing 100 and the electrode assembly 200.

[0059] Figure 1 , Figure 2 and Figure 6 A cylindrical secondary battery is illustrated as an example, but the secondary battery disclosed herein is not limited to cylindrical secondary batteries and can be applied to various forms of secondary batteries described above.

[0060] The housing 100 may include a receiving portion for accommodating the electrode assembly 200. For example, an opening 110 may be formed on a surface opposite the top surface of the housing 100, thereby opening the housing 100. The electrode assembly 200 may be accommodated within the receiving portion through the opening 110.

[0061] The detailed structure of electrode assembly 200 will be referred to Figure 3 To be discussed later.

[0062] In an exemplary embodiment, the internal space of the housing 100 (e.g., the receiving portion) can be restrictively connected to the outside via the terminal hole 120.

[0063] In an exemplary embodiment, the terminal portion 130 and the sealing member 140 can be inserted into the terminal hole 120.

[0064] According to some embodiments, the terminal portion 130 may include a rivet. For example, the secondary battery can be sealed by a riveting process in which the terminal portion 130 and the sealing member 140 are inserted and pressed into the terminal hole 120.

[0065] However, it is not limited to this; the terminal portion 130 may include any component that can be inserted into and fixed in the terminal hole 120 without limitation.

[0066] For example, terminal portion 130 may include a conductive component. For example, terminal portion 130 may include a metal or alloy component. Therefore, terminal portion 130 can be electrically connected to electrode leads, thereby being provided as an electrode terminal.

[0067] According to an exemplary embodiment, the sealing member 140 may be disposed between the housing 100 and the terminal portion 130. For example, the sealing member 140 may be integrally formed with the terminal portion 130.

[0068] In some embodiments, the sealing member 140 can be formed integrally with the terminal portion 130 by insert injection molding. For the insert injection molding process of the sealing member 140, refer to... Figures 7 to 9 To provide a more detailed explanation.

[0069] For example, the sealing member 140 can extend from inside the housing 100 to between the housing 100 and the terminal portion 130. Therefore, warping at the joint between the terminal portion 130 and the top surface of the housing 100 can be prevented, and the sealing characteristics of the secondary battery can be improved. This improves the structural stability of the secondary battery and prevents electrolyte leakage, thereby improving drive reliability.

[0070] In some embodiments, the sealing member 140 may comprise a polymer. For example, the polymer may comprise an insulating material.

[0071] For example, the sealing component 140 may comprise at least one material selected from high-density polyethylene (HDPE), perfluoroalkoxy, silicone, and polybutylene terephthalate. Therefore, the sealing properties of the secondary battery can be further enhanced, and the top surface of the housing 100 and the electrode assembly 200 can be insulated. Thus, the stability and reliability of the secondary battery can be further improved.

[0072] Figures 3 to 5 This is a schematic cross-sectional view of a secondary battery according to an exemplary embodiment. Figures 3 to 5 They are along Figure 2 A cross-sectional view of the I-I' line taken along the length of the secondary battery.

[0073] Reference Figures 3 to 5 In some embodiments, the sealing member 140 may extend along the inner surface of the housing 100, the side of the terminal hole 120, and the top surface of the housing 100. Therefore, even without a separate gasket, the sealing member 140 can fill the space between the terminal portion 130 and the housing 100. This improves the sealing characteristics of the secondary battery.

[0074] In some embodiments, the terminal portion 130 may include an exposed portion 132 disposed on the top surface of the housing 100 and an insertion portion 134 inserted into the terminal hole 120. In some embodiments, the terminal portion 130 may further include a head 136 extending along the inner surface of the housing 100 and the side of the insertion portion 134. For example, the exposed portion 132, the insertion portion 134, and the head 136 may be provided as an integral structure formed from virtually the same components.

[0075] In some embodiments, the sealing member 140 may extend along the inner surface of the housing 100 and the side of the insertion portion 134. Therefore, the sealing member 140 can adequately seal the junction between the terminal portion 130 and the housing 100, and can further improve the stability of the secondary battery.

[0076] Reference Figure 3 The diameter of the exposed portion 132 of the terminal portion 130 can be practically the same as the diameter of the insertion portion 134. In this case, the sealing member 140 can extend further along the side of the exposed portion 132, thereby exposing itself on the top surface of the housing 100. Therefore, the sealing characteristics of the terminal portion 130 and the housing 100 can be further improved.

[0077] Reference Figure 4 The diameter of the exposed portion 132 of the terminal portion 130 can be larger than the diameter of the insertion portion 134.

[0078] In some embodiments, the sealing member 140 may extend further along the top surface of the housing 100. For example, the sealing member 140 may extend along the inner surface of the housing 100, the side of the insertion portion 134, and the top surface of the housing 100. For example, the sealing member 140 may be disposed between the exposed portion 132 and the top surface of the housing 100. Therefore, the sealing characteristics of the terminal portion 130 and the housing 100 can be further improved.

[0079] Reference Figure 5 The sealing member 140 may extend further along the top surface of the housing 100 and the side surface of the exposed portion 132. For example, the sealing member 140 may extend along the inner surface of the housing 100, the side surface of the insertion portion 134, the top surface of the housing 100, and the side surface of the exposed portion 132. Therefore, the sealing characteristics of the terminal portion 130 and the housing 100 can be further improved.

[0080] In some embodiments, the sealing member 140 may completely cover the side of the terminal portion 130. Therefore, the sealing characteristics of the terminal portion 130 and the housing 100 can be further improved.

[0081] In some embodiments, the sealing member 140 may completely cover the inner side surface adjacent to the top surface of the housing 100, the inner surface opposite to the top surface of the housing 100, and the side surface of the terminal portion 130. Therefore, the driving stability and reliability of the secondary battery can be further improved.

[0082] In some embodiments, the sealing member 140 may insulate the electrode assembly 200 and the top surface of the housing 100. For example, the sealing member 140, extending along an inner surface opposite the top surface of the housing 100, may be disposed between the electrode assembly 200 and the top surface of the housing 100. Therefore, even without a separate insulator or insulating layer, short circuits and / or leakage of the secondary battery can be prevented, and stability can be improved.

[0083] By using the sealing component 140, the sealing characteristics and stability of the secondary battery can be improved even without using separate gaskets and insulation layers.

[0084] In an exemplary embodiment, the electrode assembly 200 may include a positive electrode 210 and a negative electrode 220 opposite to the positive electrode 210. The electrode assembly 200 may further include a membrane 230 disposed between the positive electrode 210 and the negative electrode 220.

[0085] The positive electrode 210 and the negative electrode 220 can be stacked alternately and repeatedly through the separator 230 to define the electrode assembly 200.

[0086] In some embodiments, a secondary battery may include a jelly roll form formed by repeatedly stacking multiple electrode stack structures or repeatedly winding an electrode assembly around a core pin (not shown).

[0087] In one embodiment, a stacked structure of a negative electrode 220, a diaphragm 230, and a positive electrode 210 is provided on the core needle, and the core needle is repeatedly wound around it to form a core shape. By removing the core needle from the core shape, an electrode assembly 200 can be formed.

[0088] like Figures 3 to 5 As shown, the positive electrode 210 may include a positive electrode current collector 212 and a positive electrode active material layer 214 disposed on at least one side of the positive electrode current collector 212. In one embodiment, the positive electrode active material layer 214 may be disposed on both sides of the positive electrode current collector 212.

[0089] The positive current collector 212 may comprise stainless steel, nickel, aluminum, titanium, or alloys thereof. The positive current collector 212 may also comprise aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver. For example, the thickness of the positive current collector 212 may be from 10 μm to 50 μm.

[0090] The positive electrode active material layer 214 may contain positive electrode active material.

[0091] For example, the positive electrode active material may comprise a lithium-nickel metal oxide. The lithium-nickel metal oxide may further comprise at least one of cobalt (Co), manganese (Mn), and aluminum (Al).

[0092] In some embodiments, the positive electrode active material or the lithium-nickel metal oxide may comprise a layered structure or a crystal structure represented by the following chemical formula 1.

[0093] [Chemical Formula 1]

[0094] Li x Ni a M b O 2+z

[0095] In chemical formula 1, the values ​​can be 0.9≤x≤1.2, 0.5≤a≤0.99, 0.01≤b≤0.5, and -0.5≤z≤0.1. As mentioned above, M can contain Co, Mn, and / or Al.

[0096] The chemical structure represented by Formula 1 indicates the bonding relationships contained in the layered or crystalline structure of the positive electrode active material, and does not exclude other additional elements. For example, M may contain Co and / or Mn, and Co and / or Mn may be provided together with Ni as the main active element of the positive electrode active material. Formula 1 is provided to represent the bonding relationships of the main active element, and it should be understood that Formula 1 includes the introduction and substitution of additional elements.

[0097] In one embodiment, in addition to the primary active element, auxiliary elements may be further included to enhance the chemical stability of the positive electrode active material or the layered / crystal structure. These auxiliary elements may be incorporated into the layered / crystal structure and form bonds; this should be understood to also include the chemical structures represented by Formula 1.

[0098] The auxiliary element may include, for example, at least one selected from Na, Mg, Ca, Y, Ti, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, Sr, Ba, Ra, P, and Zr. The auxiliary element may function as an auxiliary active element, together with Co or Mn, to contribute to the capacity / power activity of the positive electrode active material; for example, Al.

[0099] For example, the positive electrode active material or the lithium-nickel metal oxide may include a layered structure or a crystal structure represented by the following chemical formula 1-1.

[0100] [Chemical Formula 1-1]

[0101] Li x Ni a M1 b1 M2 b2 O 2+z

[0102] In chemical formula 1-1, M1 may contain Co, Mn, and / or Al. M2 may contain the aforementioned auxiliary elements. In chemical formula 1-1, the following conditions may be met: 0.9≤x≤1.2, 0.5≤a≤0.99, 0.01≤b1+b2≤0.5, -0.5≤z≤0.1.

[0103] The positive electrode active material may further include coating elements or doping elements. For example, elements that are substantially the same as or similar to the auxiliary elements described above can be used as coating elements or doping elements. For example, one or more combinations of the elements described above can be used as coating elements or doping elements.

[0104] The coating element or doping element may exist on the surface of the lithium-nickel metal oxide particles, or may penetrate through the surface of the lithium-nickel metal composite oxide particles and be contained in the bonding structure represented by chemical formula 1 or chemical formula 1-1.

[0105] The positive electrode active material may contain nickel-cobalt-manganese (NCM)-based lithium oxide. In this case, NCM-based lithium oxide with increased nickel content can be used.

[0106] Ni can be provided as a transition metal related to the power and capacity of lithium secondary batteries. Therefore, as described above, by employing a high-content (high-Ni) composition in the positive electrode active material, a high-capacity positive electrode and a high-capacity lithium secondary battery can be provided.

[0107] However, with increasing Ni content, the long-term storage stability and lifetime stability of the cathode 210 or secondary battery may relatively decrease, and side reactions with the electrolyte may also increase. However, according to exemplary embodiments, conductivity can be maintained by including Co, while lifetime stability and capacity retention characteristics can be improved by including Mn.

[0108] In the NCM-based lithium oxide, the content of Ni (e.g., the mole fraction of Ni in the total moles of nickel, cobalt, and manganese) can be 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more. In some embodiments, the content of Ni can be from 0.8 to 0.95, from 0.82 to 0.95, from 0.83 to 0.95, from 0.84 to 0.95, from 0.85 to 0.95, or from 0.88 to 0.95.

[0109] In some embodiments, the positive electrode active material can also include, respectively, a lithium cobalt oxide-based active material, a lithium manganese oxide-based active material, a lithium nickel oxide-based active material, or a lithium iron phosphate (LFP)-based active material (e.g., LiFePO4).

[0110] In some embodiments, the positive electrode active material can include, for example, a lithium-rich layered oxide (LLO) / over-lithiated oxide (OLO)-based active material, a manganese-rich (Mn-rich)-based active material, a cobalt-less (Co-less)-based active material, etc., having a chemical structure or crystal structure represented by Chemical Formula 2. These can be used alone or in combination of two or more.

[0111] [Chemical Formula 2]

[0112] p[Li2MnO3]·(1-p)[Li q JO2]

[0113] In Chemical Formula 2, 0 < p < 1, 0.9 ≤ q ≤ 1.2, and J can include at least one element selected from Mn, Ni, Co, Fe, Cr, V, Cu, Zn, Ti, Al, Mg, and B.

[0114] In the total weight of the positive electrode active material layer 214, the content of the positive electrode active material can be 40 wt% or more, 50 wt% or more, 60 wt% or more, 70 wt% or more, 80 wt% or more, or 90 wt% or more.

[0115] In the total weight of the positive electrode active material layer 214, the content of the positive electrode active material can be 99 wt% or less, 95 wt% or less, 90 wt% or less, or 85 wt% or less.

[0116] The above-mentioned positive electrode active material can be mixed in a solvent to prepare a positive electrode slurry. The positive electrode slurry can be coated / deposited on at least one side of the positive electrode current collector 212, and then dried and calendered to produce a positive electrode active material layer 214. The coating can include gravure coating, slot extrusion coating, multilayer simultaneous die coating, embossing, doctor blade coating, dip coating, bar coating, casting, and other methods.

[0117] The positive electrode active material layer 214 may further include a binder, and optionally further include a thickener, etc.

[0118] The solvent can be N-methyl-2-pyrrolidone (NMP), dimethylformamide, dimethylacetamide, N,N-dimethylaminopropylamine, ethylene oxide, tetrahydrofuran, etc.

[0119] The adhesive may include polyvinylidene fluoride (PVDF), poly(vinylidene fluoride-co-hexafluoropropylene) copolymer, polyacrylonitrile, polymethyl methacrylate, nitrile rubber (NBR), polybutadiene rubber (BR), styrene-butadiene rubber (SBR), etc. These can be used alone or in combination of two or more.

[0120] In one embodiment, a PVDF-based binder can be used as the positive electrode binder. In this case, the amount of binder used to form the positive electrode active material layer 214 can be reduced, and the amount of positive electrode active material can be relatively increased. Therefore, the power characteristics and capacity characteristics of the secondary battery can be improved.

[0121] The positive electrode slurry may further contain thickeners and / or dispersants. In one embodiment, the positive electrode slurry may further contain thickeners such as carboxymethyl cellulose (CMC).

[0122] The negative electrode 220 may include a negative electrode current collector 222 and a negative electrode active material layer 224 disposed on at least one side of the negative electrode current collector 222. In one embodiment, the negative electrode active material layer 224 may be disposed on both sides of the negative electrode current collector 222.

[0123] For example, the negative electrode current collector 222 may include a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a foam nickel, a foam copper, a polymer substrate coated with a conductive metal, etc. These may be used alone or in combination of two or more. For example, the thickness of the negative electrode current collector 222 may be 10 μm to 50 μm.

[0124] The negative electrode active material layer 224 may contain a negative electrode active material. The negative electrode active material may use a material that allows lithium ions to be intercalated and deintercalated. For example, the negative electrode active material may use carbon-based materials such as crystalline carbon, amorphous carbon, carbon composites, carbon fibers, etc.; lithium metal; lithium alloys; silicon (Si)-containing substances or tin (Sn)-containing substances, etc. These may be used alone or in combination of two or more.

[0125] The amorphous carbon may include hard carbon, soft carbon, coke, mesocarbon microbead (MCMB), mesophase pitch-based carbon fiber (MPCF), etc.

[0126] The crystalline carbon may include graphite-based carbons such as natural graphite, artificial graphite, graphitized coke, graphitized MCMB, graphitized MPCF, etc.

[0127] The lithium metal may include pure lithium metal and / or lithium metal formed with a protective layer for inhibiting dendrite growth, etc. In one embodiment, a lithium metal-containing layer deposited or coated on the negative electrode current collector 222 may be used as the negative electrode active material layer 224. In one embodiment, a lithium thin film layer may be used as the negative electrode active material layer 224.

[0128] As the elements contained in the lithium alloy, aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, indium, etc. may be listed. These may be used alone or in combination of two or more.

[0129] The silicon-containing substance may provide further increased capacity characteristics. The silicon-containing substance may include Si, SiO x (0 < x < 2), metal-doped SiO x (0 < x < 2), silicon-carbon composites, etc.

[0130] The metal may include lithium and / or magnesium, and metal-doped SiO x (0 < x < 2) may include metal silicate.

[0131] The negative electrode active material can be mixed in a solvent to prepare a negative electrode slurry. The negative electrode slurry can be coated / deposited onto the negative electrode current collector 222, followed by drying and calendering to create a negative electrode active material layer 224. The coating process can include gravure coating, slot die coating, multilayer simultaneous die coating, embossing, doctor blade coating, dip coating, bar coating, casting, and other methods. The negative electrode active material layer 224 may further contain a binder and optionally further contain conductive materials, thickeners, etc.

[0132] The solvents contained in the negative electrode slurry may include water, pure water, deionized water, distilled water, ethanol, isopropanol, methanol, acetone, n-propanol, tert-butanol, etc. These can be used alone or in combination of two or more.

[0133] The adhesive, conductive material, and thickener may be any of the aforementioned substances that can be used in the manufacture of the positive electrode 210.

[0134] In some embodiments, the negative electrode adhesive may be a styrene-butadiene-rubber (SBR) based adhesive, carboxymethyl cellulose (CMC), polyacrylic acid based adhesive, or poly(3,4-ethylenedioxythiophene) (PEDOT) based adhesive, etc. These may be used alone or in combination of two or more.

[0135] The separator 230 can be configured to prevent short circuits between the positive electrode 210 and the negative electrode 220 and to prevent ion flow. For example, the thickness of the separator can be from 10 μm to 20 μm.

[0136] For example, diaphragm 230 may include a porous polymer membrane or a porous nonwoven fabric.

[0137] The porous polymer membrane may include polyolefin-based polymers such as ethylene polymers, propylene polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers. These may be used alone or in combination of two or more.

[0138] The porous nonwoven fabric may include high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0139] The diaphragm 230 may also include a ceramic-based material. For example, inorganic particles may be coated on or dispersed in the polymer membrane to improve heat resistance.

[0140] The diaphragm 230 may have a single-layer structure or a multi-layer structure including the polymer membrane and / or nonwoven fabric described above.

[0141] For example, the electrode assembly 200 may be housed together with the electrolyte within the housing 100, thereby defining a secondary battery. According to an exemplary embodiment, the electrolyte may be a non-aqueous electrolyte.

[0142] Non-aqueous electrolytes may contain a lithium salt as the electrolyte and an organic solvent. For example, the lithium salt may be made from Li... + X - This is represented, for example, by the anion (X) of the lithium salt. - ), can be exemplified by F - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - ClO4 - PF6 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - CF3CF2SO3 - (CF3SO2)2N - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5)3C - (CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - (CF3CF2SO2)2N - wait.

[0143] The organic solvent may be, for example, propylene carbonate (PC), ethylene carbonate (EC), butene carbonate, diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, vinylene carbonate, methyl acetate (MA), ethyl acetate (EA), n-propylacetate (n-PA), 1,1-dimethylethyl acetate (DMEA), methyl propionate (MP), ethyl propionate (EP), ethyl fluoroacetate (FEA), ethyl difluoroacetate (DFEA), ethyl trifluoroacetate (TFEA), dibutyl ether, tetraethylene glycol dimethyl ether (TEGDME), and diethylene glycol dimethyl ether. DEGDME, dimethoxyethane, tetrahydrofuran (THF), 2-methyltetrahydrofuran, ethyl alcohol, isopropyl alcohol, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, γ-butyrolactone, propylene sulfite, etc. These can be used alone or in combination of two or more.

[0144] The non-aqueous electrolyte may further contain additives. These additives may include, for example, cyclic carbonate compounds, fluorinated carbonate compounds, sulfonyl lactone compounds, cyclic sulfate compounds, cyclic sulfite compounds, phosphate compounds, borate compounds, etc. These may be used alone or in combination of two or more.

[0145] The cyclic carbonate-based compound may include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), etc.

[0146] The fluorine-substituted cyclic carbonate compounds may include fluoroethylene carbonate (FEC), etc.

[0147] The sulfonyl compounds may include 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, etc.

[0148] The cyclic sulfate-based compounds may include 1,2-ethylene sulfate, 1,2-propylene sulfate, etc.

[0149] The cyclic sulfite-based compounds may include ethylene sulfite, butylene sulfite, etc.

[0150] The phosphate-based compounds may include lithium difluorobis-oxalato phosphate, lithium difluorophosphate, etc.

[0151] The borate-based compounds may include lithium bis(oxalate) borate, etc.

[0152] In some embodiments, a solid electrolyte can be used instead of the non-aqueous electrolyte. In this case, the lithium secondary battery can be made into an all-solid-state battery. Furthermore, a solid electrolyte layer can be disposed between the positive electrode 210 and the negative electrode 220 instead of the separator 230.

[0153] The solid electrolyte may include a sulfide-based electrolyte. As a non-limiting example, the sulfide-based electrolyte may include Li₂S-P₂S₅, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-LiBr, Li₂S-P₂S₅-LiCl-LiBr, Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-SiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂S₅-LiI, Li₂S-B₂S₃, and Li₂S-P₂S₅-Z. m Sn (m and n are positive numbers, Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are positive numbers, M is P, Si, Ge, B, Al, Ga, or In), Li 7-x PS 6-x Cl x (0≤x≤2), Li 7-x PS 6-x Br x (0≤x≤2), Li 7-x PS 6-x I x (0≤x≤2), etc. These can be used individually or in combination of two or more.

[0154] In one embodiment, the solid electrolyte may further include oxide-based amorphous solid electrolytes such as Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, and Li2O-B2O3-ZnO.

[0155] A positive electrode tab 215 may protrude from the positive current collector 212 and extend toward the bottom surface of the secondary battery or toward the cover plate 300. For example, multiple positive electrode tabs 215 may be electrically connected to form a positive electrode lead 217. For example, the positive electrode lead 217 may extend to or be exposed outside the cover plate 300, or may be integrated with the cover plate 300, thereby providing a positive terminal for the secondary battery.

[0156] The negative electrode tab 225 may protrude from the negative electrode current collector 222 and extend toward the top surface of the secondary battery. For example, the negative electrode tab 225 may protrude in the opposite direction to the positive electrode tab 215. For example, multiple negative electrode tabs 225 may be electrically connected to form a negative electrode lead 227. For example, the negative electrode lead 227 may be electrically connected to the terminal portion 130 to provide the terminal portion 130 as the negative terminal of the secondary battery.

[0157] Figure 6 This is a schematic plan view taken from the top surface of a secondary battery according to an exemplary embodiment.

[0158] Reference Figure 6 The sealing member 140 may expose at least a portion of the top surface of the housing 100. Therefore, the space between the terminal portion 130 and the housing 100 can be further sealed.

[0159] For example, the sealing member 140 may extend along the side of the exposed portion 132 and / or the top surface of the housing 100, thereby exposing the sealing member 140 to the outside of the secondary battery.

[0160] In some embodiments, when the sealing member 140 is viewed in a planar direction, the length D of the exposed portion 132 protruding outward can be approximately 1 mm to 5 mm, and in one embodiment, it can be approximately 1 mm to 3 mm. Within this range, external moisture or foreign matter can be further inhibited from penetrating into the interior of the secondary battery. Therefore, the stability and long-term lifespan characteristics of the secondary battery can be further improved.

[0161] The planar direction can refer to the direction from which the top surface of the secondary battery or housing 100 is viewed.

[0162] The sealing component 140 provides a secondary battery that offers improved sealing characteristics and reliability even without the use of separate gaskets and insulators.

[0163] Figures 7 to 9 This is a schematic perspective view illustrating a method for manufacturing a sealing component included in a secondary battery according to an exemplary embodiment.

[0164] Reference Figures 7 to 9 The sealing component 140 can be molded onto the terminal portion 130 by insert injection molding.

[0165] Reference Figure 7 Injection molds 10 and 20 can be prepared for molding the sealing component 140. The injection molds 10 and 20 may include a first injection mold 10 and a second injection mold 20 facing each other. For example, an injection molded part can be formed between a first surface 10a of the first injection mold 10 and a second surface 20a of the second injection mold 20 facing each other.

[0166] For example, a groove 15 for inserting the terminal portion 130 can be formed in the central portion of the first injection mold 10. A recess 25 for injecting the pre-molded part can be formed on the second surface 20a of the second injection mold 20.

[0167] Terminal portion 130 can be inserted into and coupled to the first injection mold 10. Terminal portion 130 can be provided as an insert in an insert injection molding process. For example, at least a portion of the main body of terminal portion 130 (e.g., exposed portion 132 and inserted portion 134) can be inserted into groove 15.

[0168] Reference Figure 8 The first injection mold 10, into which the terminal portion 130 is inserted, and the second injection mold 20 are combined. Then, a pre-molded part 140a can be injected through the groove 25 of the second injection mold 20. The pre-molded part 140a may contain the same material as the material contained in the sealing member 140. For example, the pre-molded part 140a may have a liquid form in which the polymer described above melts at high temperatures.

[0169] The injection of the pre-molded part 140a can be carried out under high pressure. Therefore, air present in the injection molds 10 and 20 can be quickly expelled, thereby suppressing the generation of bubbles or defects in the injection molded part.

[0170] Then, by adjusting the injection molds 10 and 20 to a predetermined temperature, the pre-injection molded part 140a in a liquid state can be solidified. Thus, the injection molded part (sealing component 140) can be formed.

[0171] Reference Figure 9 The pre-molded part 140a in a liquid state can solidify and bond together with the inserted terminal portion 130. Therefore, the terminal portion 130 and the sealing member 140 can actually be formed as a single component.

[0172] The terminal portion 130 can partially fill the groove 15 of the first injection mold 10. Therefore, a pre-molded part 140a can also be injected and solidified between the terminal portion 130 and the groove 15. Therefore, the sealing member 140 can completely cover the side of the terminal portion 130.

[0173] According to some embodiments, the sealing member 140 may not cover the top surface of the head 136 of the terminal portion 130. For example, the sealing member 140 may be formed to cover the bottom surface of the head 136 and the sides of the exposed portion 132 and the insertion portion 134.

[0174] Therefore, as described above, a sealing component 140 can be manufactured integrated with the terminal portion 130. Thus, improved sealing and insulation are provided by the terminal portion 130 and the sealing component 140, thereby improving the structural stability and driving reliability of the secondary battery.

Claims

1. A secondary battery, comprising: The housing includes a terminal hole extending through the top surface of the housing; The electrode assembly is housed within the housing; The terminal portion is inserted into the terminal hole; as well as A sealing component extends from the interior of the housing to between the housing and the terminal portion, and is disposed between the housing and the terminal portion.

2. The secondary battery according to claim 1, wherein, The sealing component extends along the inner surface of the housing, the side of the terminal hole, and the top surface of the housing.

3. The secondary battery according to claim 1, wherein, The terminal portion includes an exposed portion disposed on the top surface of the housing and an insertion portion inserted into the terminal hole.

4. The secondary battery according to claim 3, wherein, The sealing component extends along the inner surface of the housing and the side of the insertion portion.

5. The secondary battery according to claim 4, wherein, The diameter of the exposed portion is the same as the diameter of the inserted portion, and the sealing member extends further along the side of the exposed portion.

6. The secondary battery according to claim 4, wherein, The diameter of the exposed portion is larger than the diameter of the inserted portion, and the sealing member extends further along the top surface of the housing.

7. The secondary battery according to claim 4, wherein, The diameter of the exposed portion is larger than the diameter of the inserted portion, and the sealing member extends further along the top surface of the housing and the side surface of the exposed portion.

8. The secondary battery according to claim 3, wherein, When the sealing component is viewed in a planar direction, the exposed portion protrudes outward by a length of 1 mm to 3 mm.

9. The secondary battery according to claim 1, wherein, The sealing component completely covers the side of the terminal portion.

10. The secondary battery according to claim 1, wherein, The sealing component insulates the electrode assembly and the top surface of the housing.

11. The secondary battery according to claim 1, wherein, At least a portion of the sealing component is exposed on the top surface of the housing.

12. The secondary battery according to claim 1, wherein, The sealing component comprises a polymer.

13. The secondary battery according to claim 1, wherein, The sealing component comprises at least one selected from high-density polyethylene, perfluoroalkoxy, silicon polymer and polybutyl terephthalate.

14. The secondary battery according to claim 1, wherein, The sealing component is formed on the terminal portion by insert injection molding.

15. The secondary battery according to claim 1, wherein, The housing includes an opening opposite the top surface.

16. The secondary battery according to claim 15, further comprising: A cover plate is disposed at the opening and is combined with the housing.

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