Secondary battery and method for manufacturing secondary battery

Abstract

A secondary battery includes: an electrode assembly including a positive electrode, a separator, and a negative electrode; a case body accommodating the electrode assembly and having an open side; a cover coupled to the housing main body, the cover covering an open side of the housing main body; and a positive electrode terminal connected to the positive electrode and coupled to a surface of the case body. The positive electrode terminal includes: a fastening member extending into a through hole in a surface of the case body; and a sealing member between the housing body and the fastening member at a surface of the housing body. The sealing member includes an exhaust portion.

Description

Secondary batteries and methods for manufacturing secondary batteries Technical Field

[0001] An aspect of the embodiments of this disclosure relates to a secondary battery and a method for manufacturing a secondary battery. Background Technology

[0002] Unlike primary batteries, which are not designed to be (re)charged, secondary (or rechargeable) batteries are designed to be discharged and recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources to drive motors in hybrid and electric vehicles and for storing electricity (e.g., household and / or utility-scale power storage). A secondary battery typically includes an electrode assembly containing positive and negative electrodes, a housing that houses the electrode assembly, and electrode terminals connected to the electrode assembly.

[0003] During the charging and / or discharging of a secondary battery, gas may be generated inside the battery. This internal gas may cause deformation of electrode components, potentially leading to internal short circuits. Consequently, the secondary battery may catch fire. In this way, the safety of the secondary battery deteriorates.

[0004] The information disclosed in this background section is intended to enhance the understanding of the background art of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0005] Embodiments of this disclosure provide a secondary battery and a method for manufacturing a secondary battery.

[0006] These and other aspects and features of this disclosure will be described in the following description of embodiments of this disclosure, or will become apparent from the following description of embodiments of this disclosure.

[0007] A secondary battery according to one embodiment of this disclosure includes: an electrode assembly including a positive electrode, a separator, and a negative electrode; a housing body housing the electrode assembly and having an open side; a cover coupled to the housing body, the cover covering the open side of the housing body; and a positive electrode terminal connected to the positive electrode and coupled to a surface of the housing body. The positive electrode terminal includes: a fastening member extending into a through-hole in the surface of the housing body; and a sealing member located on the surface of the housing body between the housing body and the fastening member. The sealing member includes a venting portion.

[0008] According to one embodiment of this disclosure, the melting point of the exhaust portion can be in the range of approximately 120°C to approximately 125°C.

[0009] According to one embodiment of this disclosure, the fastening member may include: a head portion on the outer side of the surface of the housing body; and an extension portion extending from the head portion to the inner side of the housing body through a through hole.

[0010] According to one embodiment of this disclosure, the sealing member may be located between the housing body and at least one of the head portion and the extension portion.

[0011] According to one embodiment of this disclosure, the exhaust portion may include: a first exhaust portion between the lower side of the head portion and the housing body; and a second exhaust portion between the outer side of the extension portion and the housing body.

[0012] According to one embodiment of this disclosure, the sealing member may further include a boundary portion extending along the outer periphery of the head portion at the edge of the first vent portion, and the melting point of the boundary portion may be higher than the melting point of at least one of the first vent portion and the second vent portion.

[0013] According to one embodiment of this disclosure, the upper surface of the boundary portion may be higher than the upper surface of the first exhaust portion, and the upper surface of the head portion may be higher than the upper surface of the boundary portion.

[0014] According to one embodiment of this disclosure, the width of the first exhaust portion may be greater than the width of the head portion.

[0015] According to one embodiment of this disclosure, the corner curvature of the first exhaust portion may be less than the corner curvature of the head portion.

[0016] According to one embodiment of this disclosure, the housing body may comprise an alloy material.

[0017] According to one embodiment of this disclosure, the sealing member may comprise an insulating material.

[0018] According to one embodiment of this disclosure, the sealing member may comprise a thermoplastic resin.

[0019] According to one embodiment of the present disclosure, the positive electrode terminal may further include a terminal plate connected to the positive electrode and disposed inside the housing body, and the extension portion may penetrate the terminal plate and be connected to the terminal plate.

[0020] According to one embodiment of this disclosure, the positive electrode terminal may further include an insulating member between the terminal plate and the housing body, and the extension portion may penetrate the insulating member and be connected to the insulating member.

[0021] According to one embodiment of this disclosure, the width of the insulating member may be greater than the width of the terminal block.

[0022] According to one embodiment of this disclosure, at least a portion of the lower surface of the insulating member may be recessed corresponding to the upper surface of the terminal plate, or may include a recess corresponding to the upper surface of the terminal plate.

[0023] According to one embodiment of this disclosure, at least a portion of the insulating member may be made of the same material as the venting portion.

[0024] According to one embodiment of this disclosure, the secondary battery may further include a fixing member connected to the lower surface of the terminal block and an extension portion.

[0025] According to one embodiment of the present disclosure, the exhaust portion may include: a first exhaust portion between the lower side of the head portion and the housing body; and a second exhaust portion between the outer side of the extension portion and the housing body, and at least a portion of the second exhaust portion may be between the outer side of the extension portion and the terminal plate.

[0026] A method of manufacturing a secondary battery according to an embodiment of the present disclosure includes: inserting an electrode assembly including a positive electrode, a separator, and a negative electrode into a housing body through an open side; connecting a positive electrode terminal to a positive electrode and attaching the positive electrode terminal to a surface of the housing body; and attaching a cover to the housing body to cover the open side of the housing body. The positive electrode terminal includes: a fastening member inserted into a through-hole in the surface of the housing body; and a sealing member located on the surface of the housing body between the housing body and the fastening member, and the sealing member includes a venting portion.

[0027] According to some embodiments of this disclosure, in response to the secondary battery being exposed to high temperatures, at least a portion of the sealing member can be configured to melt, thereby venting gases inside the secondary battery to the outside. Because the sealing member functions as a venting device, the safety of the secondary battery can be improved without creating a separate venting system.

[0028] According to some embodiments of this disclosure, the sealing member including the venting portion may have a relatively low melting point, so that the secondary battery can be sealed at a temperature below the melting point, and the gas generated inside the secondary battery can be discharged (exhausted) to the outside at a temperature equal to or above the melting point.

[0029] These and other aspects and features of this disclosure will be described in the following description of embodiments of this disclosure, or will become apparent from the following description of embodiments of this disclosure.

[0030] However, the aspects and features of this disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art from the detailed description described below. Attached Figure Description

[0031] The accompanying drawings illustrate embodiments of the present disclosure and further describe aspects and features of the disclosure together with the detailed description thereof. Therefore, the present disclosure should not be construed as limited to the drawings:

[0032] Figure 1 is an exploded perspective view of an example of a secondary battery according to an embodiment of the present disclosure;

[0033] Figure 2 shows an example of a secondary battery according to an embodiment of the present disclosure;

[0034] Figure 3 is an exploded view of an example of a positive electrode terminal according to an embodiment of the present disclosure;

[0035] Figure 4 shows an example of a cross-section of a positive electrode terminal according to an embodiment of the present disclosure;

[0036] Figure 5 is a cross-sectional view of a sealing member according to an embodiment of the present disclosure;

[0037] Figure 6 is a front view of the appearance of the positive electrode terminal according to an embodiment of the present disclosure;

[0038] Figure 7 illustrates how a sealing member according to an embodiment of the present disclosure melts to release internal gas;

[0039] Figure 8 illustrates how a sealing member according to an embodiment of the present disclosure melts to release internal gas;

[0040] Figure 9 illustrates how a sealing member according to an embodiment of the present disclosure melts to release internal gas; and

[0041] Figure 10 is a flowchart of an example of a method for manufacturing a secondary battery according to an embodiment of the present disclosure. Detailed Implementation

[0042] Some embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to their conventional or dictionary meanings, but should be interpreted as being consistent with the technical spirit of the invention, based on the principle that the inventor is capable of interpreting his / her disclosure in the best manner by appropriately defining the terms and concepts.

[0043] The embodiments described in this specification and the configurations shown in the accompanying drawings are only some of the embodiments of this disclosure and do not represent all the technical ideas, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications that can replace or modify the embodiments described herein may exist at the time of filing this application.

[0044] It will be understood that when a layer or element is referred to as being “between” two layers, it can be the only layer between the two layers, or one or more intermediate layers may exist. It will be understood that when an element or layer is referred to as being “on,” “connected to,” or “linked to” another element or layer, it can be directly on, connected to, or linked to the other element or layer, or one or more intermediate elements or layers may exist. When an element or layer is referred to as being “directly” on, “directly connected to,” or “directly linked to” another element or layer, no intermediate elements or layers exist. For example, when a first element is described as being “linked” or “connected” to a second element, the first element can be directly linked to or connected to the second element, or the first element can be indirectly linked to or connected to the second element via one or more intermediate elements.

[0045] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity of illustration. The same reference numerals indicate the same elements. As used herein, the term “and / or” includes any and all combinations of one or more associated listed items. Furthermore, the use of “may” in describing embodiments of this disclosure refers to “one or more embodiments of this disclosure.” Expressions such as “at least one of…” and “any one of…” preceding / following the list of elements modify the entire list of elements, but not individual elements in the list. When phrases 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 of A, B, and C,” or “at least one selected from A, B, and C” are used to specify a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term “use” may be considered synonymous with the term “utilize.” As used herein, the terms “roughly,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to account for the inherent variations in measurements or calculations that would be apparent to a person skilled in the art.

[0046] It will be understood that while the terms first, second, third, etc., may be used to describe various elements, components, regions, layers, and / or segments, these elements, components, regions, layers, and / or segments should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or segment from another element, component, region, layer, or segment. Therefore, without departing from the teachings of the exemplary embodiments, the first element, component, region, layer, or segment discussed below may be referred to as the second element, component, region, layer, or segment.

[0047] For ease of description, this document uses spatial relative terms such as “below,” “under,” “down,” “above,” and “above” to describe the relationship between one element or feature and another element or feature as shown in the figure. It will be understood that spatial relative terms are intended 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 figure is flipped, an element described as “below” or “under” other elements or features can be oriented as “above” or “above” other elements or features. Therefore, the term “below” can encompass both above and below orientations. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0048] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to be limiting of this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It will be further understood that when used in this specification, the terms “comprising” and / or “including” specify the presence of the stated features, integers, steps, operations, elements, and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0049] Furthermore, any numerical ranges disclosed and / or enumerated herein are intended to include all subranges with the same numerical precision contained within the enumerated ranges. For example, the range “1.0 to 10.0” is intended to include all subranges between the enumerated minimum value of 1.0 and the enumerated maximum value of 10.0 (and inclusive of both), i.e., a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as 2.4 to 7.6. Any maximum numerical limit enumerated herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit enumerated in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification, including the claims, to expressly enumerate any subranges contained within the scope expressly enumerated herein.

[0050] Referring to two compared elements, features, etc., as “identical” can mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with a deviation considered low in the art, such as 5% or less. Furthermore, when a parameter is said to be consistent in a given region, this may mean that it is consistent in terms of its mean.

[0051] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0052] Placing any element "above (or below)" or "above (or below)" another element may mean that the arbitrary element can be positioned to contact the upper (or lower) surface of the element, and other elements may also be positioned between the element and any element positioned on (or below) the element.

[0053] Furthermore, it will be understood that when a component is referred to as “connected,” “linked,” or “attached” to another component, the components can be directly “connected,” “linked,” or “attached” to each other, or another component can be “between” the components.

[0054] Throughout this specification, unless otherwise stated, when “A and / or B” is used, it means A, B, or A and B. In other words, “and / or” includes any or all of the listed items. Unless otherwise indicated, when “C~D” is used, it means greater than or equal to C and less than or equal to D.

[0055] In this disclosure, for clarity of description, the dimensions and relative dimensions of the layers and regions depicted in the accompanying drawings may be enlarged. That is, the dimensions shown in the drawings are for ease of understanding only and are not limiting. Furthermore, throughout the specification, the same reference numerals indicate the same parts.

[0056] Figure 1 is an exploded perspective view of an example of a secondary battery according to an embodiment of the present disclosure, and Figure 2 shows an example of a secondary battery according to an embodiment of the present disclosure.

[0057] In one embodiment, the secondary battery 100 may include an electrode assembly 110 and a housing 140. The electrode assembly 110 includes a positive electrode, a separator, and a negative electrode, and the housing 140 is configured to receive the electrode assembly 110. In one or more embodiments, the housing 140 may include a housing body 120 that receives the electrode assembly 110 and has an open side (e.g., one face of the housing body 120 in the D3 direction may be open) and a cover 130 coupled to the housing body 120 and covering the open side of the housing body 120. In one or more embodiments, the electrode assembly 110 may be wound or laminated with the separator, which serves as an insulator, between the positive and negative electrodes. The housing 140 illustrated in FIG. 1 may comprise an alloy material. For example, the housing 140 may comprise stainless steel (SUS), such that the secondary battery 100 may be an SUS can-type secondary battery, but this disclosure is not limited thereto. In one or more embodiments, the housing 140 may be formed of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel to form the overall appearance of the secondary battery 100.

[0058] The positive electrode of a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0059] Based on a 100 wt% positive electrode active material layer, the content of the positive electrode active material is in the range of about 90 wt% to about 99 wt%, and based on the 100 wt% positive electrode active material layer, the contents of the binder and the conductive material are in the range of about 0.5 wt% to about 5 wt%, respectively.

[0060] The current collector can be aluminum (Al), but is not limited to this.

[0061] As the positive electrode active material, compounds capable of reversibly inserting / deintercalating lithium (e.g., lithiation intercalation compounds) can be used. For example, at least one of lithium and a composite oxide of a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0062] The composite oxide can be a lithium transition metal composite oxide, and examples of it can include lithium nickel oxides, lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel manganese oxides, or combinations thereof.

[0063] As an example, a compound represented by any of the following molecular formulas can be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b- c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Coc L 1 d G e O2 (0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); Li a NiG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4 (0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4 (0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); and Li a FePO4 (0.90≤a≤1.8).

[0064] In the above molecular formulas: A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L 1 It is Mn, Al, or a combination thereof.

[0065] The negative electrode plate for a lithium secondary battery may include a current collector and a negative electrode active material layer disposed on the current collector. The negative electrode active material layer may include a negative electrode active material and may further include a binder and / or a conductive material.

[0066] For example, the negative electrode active material layer may include about 90 wt% to about 99.5 wt% of negative electrode active material, about 0.5 wt% to about 5 wt% of binder, and about 0 wt% to about 5 wt% of conductive material.

[0067] Non-aqueous binders, aqueous binders, dry binders, or combinations thereof can be used as binders. When an aqueous binder is used as the negative electrode binder, it may further include a cellulose-based compound capable of imparting viscosity.

[0068] As the negative electrode current collector, one selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and combinations thereof may be used.

[0069] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, a lithium metal alloy, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0070] The material capable of reversibly intercalating / deintercalating lithium ions may be a carbon-based negative electrode active material, which may include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon may include graphite, such as natural graphite or artificial graphite, and examples of amorphous carbon may include soft carbon, hard carbon, pitch carbide, mesophase pitch carbide, sintered coke, etc.

[0071] As the material capable of doping and dedoping lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material may be used. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiO x (0 < x < 2), a Si-based alloy, or a combination thereof.

[0072] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0073] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core.

[0074] Depending on the type of the lithium secondary battery, a separator may be present between the first electrode plate (e.g., the negative electrode) and the second electrode plate (e.g., the positive electrode). As the separator, polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film of two or more layers thereof may be used.

[0075] The separator may include a porous substrate and a coating including an organic material, an inorganic material, or a combination thereof on one or both surfaces of the porous substrate.

[0076] The organic material may include a polyvinylidene fluoride-based heavy antibody or a polymer (meth)acrylic polymer.

[0077] The inorganic material may include inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof, but is not limited thereto.

[0078] Organic and inorganic materials can be mixed in a coating, or they can be in the form of a coating containing organic materials and a coating containing inorganic materials being layered on top of each other.

[0079] In one embodiment, the electrode assembly 110 may have a positive electrode tab 112 connected to one side of the positive electrode and a negative electrode tab 114 connected to one side of the negative electrode. The positive electrode tab 112 and the negative electrode tab 114 can be connected to the uncoated portions of the positive and negative electrodes, respectively, by welding tabs, or formed by stamping to remove the uncoated portions of the positive and negative electrodes. After the electrode assembly 110 has been wound, the positive electrode tab 112 and the negative electrode tab 114 may be arranged parallel (or substantially parallel) to each other with a gap between them. However, the positive electrode tab 112 and the negative electrode tab 114 may also be placed on different sides (e.g., opposite sides) of the secondary battery. The electrode assembly 110 may have any suitable structure including electrode tabs.

[0080] In one embodiment, the housing body 120 may include a positive electrode terminal 122 and a negative electrode terminal 124. In one or more embodiments, the positive electrode terminal 122 may be electrically connected to the positive electrode tab 112 of the electrode assembly 110, and the negative electrode terminal 124 may be electrically connected to the negative electrode tab 114 of the electrode assembly 110. Furthermore, the positive electrode terminal 122 and the negative electrode terminal 124 may be on a surface of the housing body 120 other than the open side (such as the other side of the housing body 120 in the D1 direction). The positions of the positive electrode terminal 122 and the negative electrode terminal 124 according to this disclosure are not limited to the positions illustrated in FIG. 1, and may be located in any other suitable position.

[0081] In one embodiment, the positive electrode terminal 122 may include a fastening member inserted into a through-hole in the surface of the housing body 120 and a sealing member on the surface of the housing body 120 between the housing body 120 and the fastening member. In one or more embodiments, the sealing member may include a venting portion. Examples of the positive electrode terminal 122 will be described in detail with reference to Figures 3 through 9.

[0082] In one embodiment, the housing body 120 may include an electrolyte inlet 126. In one or more embodiments, the electrolyte inlet 126 may be a through-hole in a surface of the housing body 120 (such as a surface of the housing body 120 in the D1 direction), and the electrolyte inlet 126 may be configured to allow electrolyte injection into the housing 140 of the secondary battery 100 after the housing body 120 and the cover 130 have been engaged and sealed together. After the electrolyte has been injected, a sealing plug 150 may be coupled to the electrolyte inlet 126. Although in the illustrated embodiment the electrolyte inlet 126 is positioned between the positive electrode terminal 122 and the negative electrode terminal 124, this disclosure is not limited thereto, and the electrolyte inlet 126 may be located in any other suitable location.

[0083] In one embodiment, a receiving portion for accommodating the electrode assembly 110 (e.g., formed by extrusion, etc.) is located in the central region of the housing body 120. Furthermore, a flange 128 may extend along the upper edge of the receiving portion in, for example, in four directions (e.g., the flange 128 may extend around the periphery of the receiving portion).

[0084] In one embodiment, the housing body 120 and the cover 130 may be joined together to form the appearance of the secondary battery 100. In one or more embodiments, the housing body 120 and the cover 130 may be joined by processes used to join metal components together, such as welding, brazing, and / or soldering. In one or more embodiments, the flange 128 of the housing body 120 and the edge of the cover 130 may be joined together. Furthermore, after the housing body 120 and the cover 130 have been joined, a portion of the flange 128 may be laser-cut to remove a portion of the flange 128, thereby increasing the energy density of the secondary battery 100.

[0085] The secondary battery 100 can be a lithium-ion battery cell, a sodium-ion battery cell, etc. However, the scope of this disclosure is not limited thereto, and examples of the secondary battery 100 can include any battery capable of repeatedly providing power through charging and discharging. In one embodiment where the secondary battery 100 is a lithium-ion battery cell, it can be used in electric vehicles (EVs) due to its excellent lifespan and high rate performance. For example, it can be used in hybrid vehicles, such as plug-in hybrid electric vehicles (PHEVs). Furthermore, lithium-ion battery cells can be used in applications requiring large amounts of energy storage, such as electric bicycles and power tools.

[0086] Figure 3 is an exploded view of a positive electrode terminal 122 according to an embodiment of the present disclosure. In one embodiment, the positive electrode terminal 122 may include a fastening member 310, a sealing member 320, a terminal plate 330 connected to the positive electrode or the positive electrode tab 112 in Figure 1, an insulating member 340, and a fixing member 350 coupled to the lower surface of the terminal plate 330 and the fastening member 310. In one or more embodiments, the fastening member 310 may extend into or be inserted into a through-hole in the surface of the housing body 120. Furthermore, the sealing member 320 may be located on the surface of the housing body 120 between the housing body 120 and the fastening member 310 (e.g., placed on the outer side of the surface of the housing body 120 and between the housing body 120 and the fastening member 310). At least a portion of the sealing member 320 may be inserted into the through-hole of the housing body 120 to seal the space between the fastening member 310 and the through-hole of the housing body 120.

[0087] In one embodiment, the terminal plate 330 may be placed inside the housing body 120 (e.g., inside a receiving portion of the housing body 120). Furthermore, the insulating member 340 may be between the terminal plate 330 and the housing body 120 (e.g., on a surface in which a through-hole of the housing body 120 is formed). In one or more embodiments, at least a portion of the fastening member 310 may penetrate the terminal plate 330 and the insulating member 340, and may be coupled to both the terminal plate 330 and the insulating member 340.

[0088] In one embodiment, the sealing member 320 may include a venting portion. In one or more embodiments, the sealing member 320 may include a thermoplastic resin. Furthermore, the melting point of the venting portion may be in the range of about (approximately) 120°C to about (approximately) 125°C. In one or more embodiments, the venting portion may comprise a polypropylene (PP) material having a relatively low melting point, but this disclosure is not limited thereto. Further, the sealing member 320 may comprise an insulating material. Accordingly, at temperatures below the melting point, the sealing member 320 may insulate the space between the fastening member 310 and the housing body 120, and at temperatures equal to or above the melting point, at least a portion of the sealing member 320 may melt to vent (exhaust) gases generated in the secondary battery 100 to the outside.

[0089] Figure 4 illustrates an example of a cross-section of a positive electrode terminal according to one embodiment of the present disclosure. In one embodiment, the positive electrode terminal may be connected to a positive electrode and may be coupled to a housing body 120 (e.g., a surface of the housing body 120). In one or more embodiments, the positive electrode terminal may include a fastening member 310, a sealing member 320, a terminal plate 330, and an insulating member 340. The fastening member 310 is inserted into a through-hole 360 ​​in a surface of the housing body 120. The sealing member 320 is located on the surface of the housing body 120 between the housing body 120 and the fastening member 310 (e.g., on the outer side of the surface of the housing body 120 and between the housing body 120 and the fastening member 310). The terminal plate 330 is connected to the positive electrode and is inside a receiving portion of the housing body 120. The insulating member 340 is located between the terminal plate 330 and the housing body 120 (e.g., on the surface of the housing body 120 in which the through-hole is formed).

[0090] In one embodiment, the fastening member 310 may include a head portion 312 on the outer side of the housing body 120 (e.g., on the outer side of the surface of the housing body 120) and an extension portion 314 extending from the head portion 312 to the inner side of the housing body 120 through a through-hole 360 ​​and inserted into the through-hole 360. In one or more embodiments, a sealing member 320 may be located between the housing body 120 and at least one of the head portion 312 and the extension portion 314.

[0091] In one embodiment, the sealing member 320 may include a venting portion. In one or more embodiments, the melting point of the venting portion may be in the range of about (approximately) 120°C to about (approximately) 125°C, but this disclosure is not limited thereto. In one or more embodiments, the venting portion of the sealing member 320 may be configured to melt due to the deterioration of the secondary battery 100. In one or more embodiments, the venting portion may include a first venting portion 322 disposed between the lower side of the head portion 312 of the fastening member 310 and the housing body 120 (e.g., the surface in which a through hole is formed in the housing body 120) and a second venting portion 324 disposed between the outer side of the extension portion 314 of the fastening member 310 and the housing body 120 (e.g., the inner side of the through hole in the surface of the housing body 120). Accordingly, in one or more embodiments, the entire sealing member 320 may be a venting portion.

[0092] In one embodiment, the sealing member 320 may comprise an insulating material. Furthermore, the sealing member 320 may comprise a thermoplastic resin. Accordingly, at temperatures below the melting point of the material of the sealing member 320, the sealing member 320 can insulate the space between the fastening member 310 and the housing body 120, and at temperatures equal to or above the melting point, at least a portion of the sealing member 320 may be configured to melt to release (exhaust) gases generated in the secondary battery to the outside.

[0093] In one embodiment, the extension 314 may penetrate the terminal plate 330 and be connected to the terminal plate 330. Accordingly, the fastening member 310 may be electrically connected to the terminal plate 330. Furthermore, the extension 314 of the fastening member 310 may penetrate the insulating member 340 and be connected to the insulating member 340. In one or more embodiments, the insulating member 340 may insulate the space between the terminal plate 330 connected to the positive electrode and the housing body 120. Further, at least a portion of the insulating member 340 may be made of the same material as the venting portion.

[0094] In one embodiment, the terminal plate 330 may be coupled to the lower surface of the insulating member 340. In one or more embodiments, at least a portion of the lower surface of the insulating member 340 may be recessed corresponding to the upper side or upper surface of the terminal plate 330 (e.g., the terminal plate 330 may be disposed in a recess in the insulating member 340). Furthermore, the width w2 of the insulating member 340 may be greater than the width w1 of the terminal plate 330. As a result, the terminal plate 330 may be coupled to a recessed area (e.g., a recess) in the lower surface of the insulating member 340.

[0095] In one embodiment, the positive electrode terminal may further include a fixing member 350 connected to the lower surface of the terminal plate 330 and an extension 314 of the fastening member 310. In one or more embodiments, the fixing member 350 may secure the terminal plate 330 and the insulating member 340 between the fixing member 350 and the housing body 120. In one or more embodiments, the fixing member 350 may be a rivet, but this disclosure is not limited thereto.

[0096] As a result, in response to the secondary battery being exposed to high temperatures, at least a portion of the sealing member can melt, thereby venting the gas generated inside the casing to the outside. Since the sealing member acts as a venting device, the safety of the secondary battery can be improved without creating a separate venting system.

[0097] FIG5 is a cross-sectional view of a sealing member 420 according to an embodiment of the present disclosure, and FIG6 is a front view of a positive electrode terminal according to an embodiment of the present disclosure. In one embodiment, the positive electrode terminal may include a fastening member 410 inserted into a through hole in the housing body 120 and a sealing member 420 disposed on the outside of the housing body 120 between the housing body 120 and the fastening member 410. For ease of description, the terminal plate, insulating member, and fixing member inside the housing body 120 are not shown in FIG5 and FIG6.

[0098] In one embodiment, the fastening member 410 may include a head portion 412 on the outer side of the housing body 120 (e.g., on the outer side of the surface of the housing body 120) and an extension portion 414 extending from the head portion 412 to the inner side of the housing body 120 through a through-hole. In one or more embodiments, at least a portion of the sealing member 420 may be between the housing body 120 and the head portion 412. In one or more embodiments, at least a portion of the sealing member 420 may be between the housing body 120 and the extension portion 414.

[0099] In one embodiment, the sealing member 420 may include a first venting portion 422 between the lower side of the head portion 412 and the housing body 120 (e.g., the surface in which a through hole is formed in the housing body 120) and a second venting portion 424 between the outer side of the extension portion 414 and the housing body 120 (e.g., the inner side of the through hole in the surface of the housing body 120). Furthermore, the sealing member 420 may further include a boundary portion 426 at the edge of the first venting portion 422. In one or more embodiments, the boundary portion 426 may extend along the head portion 412 of the fastening member 410 (e.g., the outer periphery of the head portion 412).

[0100] In one embodiment, the melting points of the first vent portion 422 and the second vent portion 424 may be in the range of about (approximately) 120°C to about (approximately) 125°C. Furthermore, the melting point of the boundary portion 426 may be higher than the melting point of at least one of the first vent portion 422 and the second vent portion 424. Accordingly, at temperatures below the melting point, the sealing member 420 can insulate the space between the fastening member 410 and the housing body 120, and at temperatures equal to or above the melting point, the first vent portion 422 and the second vent portion 424 can melt, thereby releasing (expelling) the gas generated in the secondary battery.

[0101] In one embodiment, the upper surface of the sealing member 420 may be recessed corresponding to the head portion 412. In one or more embodiments, the upper surface of the boundary portion 426 may be higher than the upper surface of the first vent portion 422, such that the boundary portion 426 and the first vent portion 424 together form a recess and placement portion configured to receive the head portion 412 of the fastening member 410. Furthermore, the upper surface of the head portion 412 may be higher than the upper surface of the boundary portion 426.

[0102] In the embodiment shown in Figure 6, the width w2 of the first exhaust portion 422 can be greater than the width w1 of the head portion 412. Furthermore, the height h2 of the first exhaust portion 422 can be greater than the height h1 of the head portion 412. Further, the corner curvature R1 of the first exhaust portion 422 can be less than the corner curvature R2 of the head portion 412. Accordingly, in response to the melting of the first exhaust portion 422 and the second exhaust portion 424 due to deterioration, the internal gas of the secondary battery can be discharged (exhausted) through the gap between the head portion 412 and the boundary portion 426.

[0103] Figure 7 illustrates how a sealing member according to one embodiment of the present disclosure melts to release (exhaust) internal gas. In one embodiment, the sealing member between the housing body 120 and the fastening member 310 can seal the space between the housing body 120 and the fastening member 310. In one or more embodiments, the sealing member may include an venting portion. The melting point of the venting portion may be in the range of about (approximately) 120°C to about (approximately) 125°C, and the venting portion may melt due to the degradation of the secondary battery. That is, due to the degradation of the secondary battery, at least a portion of the sealing member may melt to open the space between the housing body 120 and the fastening member 310. Accordingly, the internal gas of the secondary battery can be released (exhausted) to the outside through this space between the housing body 120 and the fastening member 310.

[0104] Figure 8 illustrates how a sealing member 820, according to one embodiment of the present disclosure, melts to release (exhaust) internal gases. In one embodiment, the sealing member 820 may be located on the surface of the housing body 120 between the housing body 120 and the fastening member 810 (e.g., on the outer surface of the housing body 120 and between the housing body 120 and the fastening member 810). Furthermore, an insulating member 840 may be located inside the housing body 120 between the housing body 120 (e.g., on the surface in which through-holes in the housing body 120 are formed) and the terminal plate 830. In one or more embodiments, the sealing member 820 and the insulating member 840 may comprise an insulating material.

[0105] In one embodiment, the sealing member 820 may comprise a thermoplastic resin. In one or more embodiments, the sealing member 820 may include a venting portion. In one or more embodiments, the melting point of the venting portion may be in the range of about (approximately) 120°C to about (approximately) 125°C. In one or more embodiments, at least a portion of the insulating member 840 may be made of the same material as the venting portion. In response to degradation of the secondary battery, at least a portion of the insulating member 840 and the venting portion of the sealing member 820 may melt. Accordingly, gas in the housing body 120 may be discharged (exhausted) to the outside of the housing body 120 along the path opened due to the melting of at least a portion of the insulating member 840 and the venting portion of the sealing member 820.

[0106] In Figure 8, the insulating material 840 has been completely melted, but this disclosure is not limited thereto. Only a portion of the insulating material 840 may be melted to form a path through which internal gases can be discharged (exhausted) to the outside of the housing body 120.

[0107] Figure 9 illustrates how a sealing member 920 according to one embodiment of the present disclosure melts to release (exhaust) internal gases. In one embodiment, the sealing member 920 may be located on the surface of the housing body 120 between the housing body 120 and the fastening member 810 (e.g., on the outer side of the surface of the housing body 120 and between the housing body 120 and the fastening member 910). In one or more embodiments, the fastening member 910 may include a head portion 912 on the outer side of the housing body 120 (e.g., on the outer side extending to the surface of the housing body 120) and an extension portion 914 extending from the head portion 912 to the inner side of the housing body 120 through a through-hole.

[0108] In one embodiment, the sealing member 920 may include a venting portion. In one or more embodiments, the venting portion may include a first venting portion 922 between the lower side of the head portion 912 and the housing body 120 (e.g., the surface in which a through hole is formed in the housing body 120) and a second venting portion 924 between the outer side of the extension portion 914 and the housing body 120 (e.g., the inner side of the through hole in the surface of the housing body 120). In one or more embodiments, at least a portion of the second venting portion 924 may be between the outer side of the extension portion 914 and the terminal plate 930. That is, at least a portion of the second venting portion 924 may extend through the housing body 120 and the insulating member 940 disposed between the terminal plate 930 and the housing body 120 to the terminal plate 930, thereby the second venting portion 924 between the outer side of the extension portion 914 and the housing body 120 may further extend between the outer side of the extension portion 914 and the terminal plate 930. In this embodiment, at least a portion of the extension portion 914 may be electrically connected to the terminal plate 930.

[0109] In one embodiment, the sealing member 920 may comprise a thermoplastic resin. In one or more embodiments, the melting points of the first vent portion 922 and the second vent portion 924 may be in the range of about (approximately) 120°C to about (approximately) 125°C. In response to degradation of the secondary battery, the first vent portion 922 and the second vent portion 924 may melt. Accordingly, gas in the housing body 120 may be discharged (exhausted) to the outside of the housing body 120 along the path opened due to the melting of the first vent portion 922 and the second vent portion 924.

[0110] Figure 10 is a flowchart of an example of a method 1000 for manufacturing a secondary battery according to an embodiment of the present disclosure. In one embodiment, the method 1000 for manufacturing a secondary battery may begin at S1010 by inserting an electrode assembly including a positive electrode, a separator, and a negative electrode into a housing body having an open side. In one or more embodiments, the housing body may comprise an alloy material such as SUS. Subsequently, at S1020, a positive electrode terminal may be connected to the positive electrode and attached to a surface of the housing body (e.g., a surface of the housing body other than the open side). Then, at S1030, a cover may be attached to the housing body to cover the open side of the housing body. The cover may comprise an alloy material.

[0111] In one embodiment, the positive electrode terminal may include a fastening member inserted into a through-hole in the surface of the housing body, and a sealing member on the surface of the housing body between the housing body and the fastening member (e.g., on the outer side of one surface of the housing body and between the housing body and the fastening member). In one or more embodiments, the sealing member may include a venting portion. The melting point of the venting portion may be in the range of about (approximately) 120°C to about (approximately) 125°C, but this disclosure is not limited thereto.

[0112] In one embodiment, the fastening member may include a head portion on the outer side of the housing body (e.g., on the outer side of a surface extending to the housing body) and an extension portion extending from the head portion to the inner side of the housing body through a through-hole and inserted into the through-hole. In this embodiment, a sealing member may be placed between the housing body and at least one of the head portion and the extension portion.

[0113] In one embodiment, the venting portion may include a first venting portion between the lower side of the head portion and the housing body (e.g., the surface in which a through-hole of the housing body is formed) and a second venting portion between the outer side of the extension portion and the housing body (e.g., the inner side of a through-hole in the surface of the housing body). In this embodiment, the sealing member may further include a boundary portion disposed at the edge of the first venting portion and extending along the outer periphery of the head portion. In one or more embodiments, the melting point of the boundary portion may be higher than the melting point of the first venting portion. Furthermore, at least a portion of the second venting portion may be disposed between the outer side of the extension portion and the terminal plate.

[0114] In one embodiment, the upper surface of the boundary portion may be higher than the upper surface of the first exhaust portion, and the upper surface of the head portion may be higher than the lower surface of the boundary portion. Furthermore, the width of the first exhaust portion may be greater than the width of the head portion. Additionally, the corner curvature of the first exhaust portion may be less than the corner curvature of the head portion.

[0115] In one embodiment, the sealing member may comprise an insulating material. In one or more embodiments, the sealing member may comprise a thermoplastic resin.

[0116] In one embodiment, the positive electrode terminal may further include a terminal plate connected to the positive electrode and disposed within the housing body. In this embodiment, the extension portion may penetrate the terminal plate and be coupled to the terminal plate. Furthermore, the positive electrode terminal may further include a fixing member coupled to the lower surface of the terminal plate and the extension portion.

[0117] In one embodiment, the positive electrode terminal may further include an insulating member between the terminal plate and the housing body. In this embodiment, the extension portion may penetrate the insulating member and be coupled to the insulating member. In one or more embodiments, at least a portion of the insulating member may be made of the same material as the venting portion.

[0118] In one embodiment, the width of the insulating member may be greater than the width of the terminal plate. Furthermore, at least a portion of the lower surface of the insulating member may include a recess corresponding to the upper side of the terminal plate.

[0119] While this disclosure has been described above with reference to embodiments thereof, it is not limited thereto. Those skilled in the art can make various modifications and variations thereto within the spirit and equivalent scope of the claims.

Claims

1. A secondary battery, comprising: Electrode assembly, including a positive electrode, a diaphragm, and a negative electrode; The housing body houses the electrode assembly and has an open side; A cover, attached to the housing body, covers the open side of the housing body; and a positive electrode terminal, connected to the positive electrode and coupled to the surface of the housing body, wherein the positive electrode terminal includes: a fastening member extending into a through hole in the surface of the housing body; And a sealing member, located on the surface of the housing body between the housing body and the fastening member, wherein the sealing member includes an venting portion.

2. The secondary battery according to claim 1, wherein the melting point of the venting portion is in the range of 120°C to 125°C.

3. The secondary battery according to claim 1, wherein the fastening member comprises: The head portion is located on the outer side of the surface of the housing body; And an extension portion that extends from the head portion to the inside of the housing body through the through hole.

4. The secondary battery according to claim 3, wherein the sealing member is between the housing body and at least one of the head portion and the extension portion.

5. The secondary battery according to claim 3, wherein the venting section comprises: The first exhaust section is located between the lower side of the head section and the housing body; And a second exhaust portion, located between the outer side of the extension and the housing body.

6. The secondary battery of claim 5, wherein the sealing member further includes a boundary portion extending along the outer periphery of the head portion at the edge of the first vent portion, and wherein the melting point of the boundary portion is higher than the melting point of at least one of the first vent portion and the second vent portion.

7. The secondary battery according to claim 6, wherein the upper surface of the boundary portion is higher than the upper surface of the first vent portion, and wherein the upper surface of the head portion is higher than the upper surface of the boundary portion.

8. The secondary battery according to claim 5, wherein the width of the first venting portion is greater than the width of the head portion.

9. The secondary battery according to claim 5, wherein the corner curvature of the first exhaust portion is less than the corner curvature of the head portion.

10. The secondary battery according to any one of claims 1 to 9, wherein the casing body comprises an alloy material.

11. The secondary battery according to any one of claims 1 to 9, wherein the sealing member comprises an insulating material.

12. The secondary battery according to any one of claims 1 to 9, wherein the sealing member comprises a thermoplastic resin.

13. The secondary battery according to any one of claims 3 to 9, wherein: The positive electrode terminal further includes a terminal plate connected to the positive electrode and disposed inside the housing body, and the extension portion penetrates the terminal plate and is connected to the terminal plate.

14. The secondary battery according to claim 13, wherein: The positive electrode terminal further includes an insulating member between the terminal plate and the housing body, and the extension portion penetrates the insulating member and is connected to the insulating member.

15. The secondary battery according to claim 14, wherein the width of the insulating member is greater than the width of the terminal plate.

16. The secondary battery according to claim 14, wherein at least a portion of the lower surface of the insulating member is recessed corresponding to the upper surface of the terminal plate.

17. The secondary battery of claim 14, wherein at least a portion of the insulating member is made of the same material as the venting portion.

18. The secondary battery of claim 13, further comprising a fixing member connected to the lower surface of the terminal plate and the extension portion.

19. The secondary battery according to claim 13, wherein the venting portion comprises: The first exhaust section is located between the lower side of the head section and the housing body; And a second exhaust portion, between the outer side of the extension portion and the housing body, wherein at least a portion of the second exhaust portion is between the outer side of the extension portion and the terminal plate.

20. A method for manufacturing a secondary battery, comprising: An electrode assembly, including a positive electrode, a diaphragm, and a negative electrode, is inserted into the housing body through the open side of the housing body. The positive electrode terminal is connected to the positive electrode, and the positive electrode terminal is coupled to the surface of the housing body; And attaching a cover to the housing body to cover the open side of the housing body, wherein the positive electrode terminal includes: a fastening member extending into a through hole in the surface of the housing body; And a sealing member, located on the surface of the housing body between the housing body and the fastening member, wherein the sealing member includes an venting portion.

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