Electrode assembly and method of manufacturing secondary battery including the same

Abstract

The present disclosure relates to an electrode assembly and a method of manufacturing a secondary battery including the same. An electrode assembly according to the present disclosure includes a positive electrode plate, a negative electrode plate, a separator between the positive electrode plate and the negative electrode plate, and an electrode tab electrically connected to the positive electrode plate. The electrode tab includes a first portion including a first metal and a second portion including a second metal at least partially surrounding the first portion.

Description

Technical Field

[0001] Various aspects of embodiments of this disclosure relate to electrode assemblies and methods of manufacturing secondary batteries including electrode assemblies. Background Technology

[0002] A rechargeable battery is a type of battery that can be charged and discharged multiple times. Rechargeable batteries are widely used in various applications, including electronic devices (such as smartphones, laptops, and tablets), electric vehicles, solar power systems, and emergency power systems. In particular, lithium-ion batteries, with their high energy density and excellent charge / discharge efficiency, are used in various electronic devices and electric vehicles.

[0003] In the event of an external short circuit or similar condition, the internal pressure within a single secondary battery cell may increase, potentially triggering the current interruption device (CID). However, since the CID may only be activated when the temperature and / or pressure of a single secondary battery cell rises significantly, relying solely on the CID could damage adjacent secondary battery cells in the battery pack. Therefore, additional devices are required besides the CID to prevent damage to adjacent secondary battery cells.

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

[0005] To address the problems described above, various aspects of the embodiments of this disclosure provide an electrode assembly and a method for manufacturing a secondary battery including the electrode assembly.

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

[0007] According to one embodiment of the present disclosure, an electrode assembly includes: a positive electrode plate, a negative electrode plate, a diaphragm located between the positive electrode plate and the negative electrode plate, and an electrode terminal block electrically connected to the positive electrode plate, wherein the electrode terminal block includes a first portion comprising a first metal and a second portion comprising a second metal that at least partially surrounds the first portion.

[0008] According to one embodiment of this disclosure, the melting point of the second metal may be higher than that of the first metal.

[0009] According to one embodiment of this disclosure, the melting point of the first metal can be in the range of 50°C to 280°C.

[0010] According to one embodiment of this disclosure, the first metal may be an alloy of at least two of arsenic (As), lead (Pb), tin (Sn), cadmium (Cd), and indium (In), and the second metal may be a metal including aluminum (Al).

[0011] According to one embodiment of the present disclosure, the first portion may be located at the center of the electrode tab, and all surfaces of the first portion are surrounded by the second portion.

[0012] According to one embodiment of this disclosure, at least one surface of the first portion may be exposed to the outside of the electrode tab.

[0013] According to one embodiment of the present disclosure, the electrode pad may include: a first plate-shaped portion made of a first metal; a second plate-shaped portion made of a second metal and disposed on a first surface of the first plate-shaped portion; and a third plate-shaped portion made of the second metal and disposed on a second surface of the first plate-shaped portion opposite to the first surface, wherein a pair of side surfaces of the first plate-shaped portion may be exposed to the outside of the electrode pad.

[0014] According to one embodiment of this disclosure, the thickness of the first portion may be less than 30% of the thickness of the electrode tab.

[0015] According to one embodiment of this disclosure, the width of the first portion may be at least 75% of the width of the electrode tab.

[0016] According to one embodiment of the present disclosure, a method of manufacturing an electrode terminal block may include: positioning a first plate-shaped portion made of a first metal between two second plate-shaped portions, each of the two second plate-shaped portions being made of a second metal; and performing a rolling process on the first plate-shaped portion and the two second plate-shaped portions.

[0017] According to one embodiment of this disclosure, in the rolling process, the thickness of the second portion located on the upper surface of the first portion and the thickness of the second portion located on the lower surface of the first portion can be the same.

[0018] According to one embodiment of this disclosure, the electrode terminals are configured such that when their temperature rises to a temperature above the melting point of the first metal, the first portion melts and then the second portion is short-circuited.

[0019] According to one embodiment of this disclosure, the first molten portion can be discharged to the outside of the electrode terminals.

[0020] According to one embodiment of the present disclosure, a method for manufacturing a secondary battery includes: disposing an electrode assembly within a housing; electrically connecting electrode terminals of the electrode assembly to a cover assembly; and attaching the cover assembly to one end of the housing, wherein the electrode terminals include a first portion comprising a first metal and a second portion comprising a second metal that at least partially surrounds the first portion.

[0021] According to one embodiment of the present disclosure, the method may further include: preparing a first plate-shaped portion made of a first metal; preparing two second plate-shaped portions, each of the two second plate-shaped portions being made of a second metal; positioning the first plate-shaped portion between the two second plate-shaped portions; and performing a rolling process on the first plate-shaped portion and the two second plate-shaped portions.

[0022] According to one embodiment of this disclosure, the melting point of the second metal may be higher than that of the first metal.

[0023] According to one embodiment of this disclosure, the first metal may be an alloy of at least two of arsenic (As), lead (Pb), tin (Sn), cadmium (Cd), and indium (In), and the second metal may be a metal including aluminum (Al).

[0024] According to one embodiment of the present disclosure, the first portion may be located at the center of the electrode tab, and all surfaces of the first portion are surrounded by the second portion.

[0025] According to one embodiment of this disclosure, at least one surface of the first portion may be exposed to the outside of the electrode tab.

[0026] According to one embodiment of this disclosure, performing a rolling process may include controlling the thickness of a second portion located on the upper surface of a first portion and the thickness of a second portion located on the lower surface of a first portion to be the same.

[0027] According to some embodiments of this disclosure, a secondary battery including an electrode assembly includes electrode terminals (e.g., positive electrode terminals) capable of short-circuiting, thereby minimizing damage to the battery pack before the secondary battery cells undergo internal degradation and increased internal pressure.

[0028] However, the aspects and features of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the detailed description below that other aspects and features not mentioned will be apparent. Attached Figure Description

[0029] The accompanying drawings illustrate embodiments of the present disclosure and, together with the detailed description of the present disclosure, further describe aspects and features of the present disclosure. Therefore, the present disclosure should not be construed as limited to the drawings.

[0030] Figure 1Examples of cylindrical secondary batteries according to some embodiments of the present disclosure.

[0031] Figure 2 This is a perspective view of the electrode terminals of a secondary battery according to a first embodiment of the present disclosure.

[0032] Figure 3 Parts (a) and (b) are examples of methods for manufacturing electrode terminals of a secondary battery according to some embodiments of the present disclosure.

[0033] Figure 4 Parts (a)-(c) illustrate the short-circuit process of the electrode terminals in a secondary battery according to some embodiments of the present disclosure.

[0034] Figure 5 and Figure 6 Each of the electrode terminals of a secondary battery according to a second embodiment of the present disclosure is illustrated.

[0035] Figure 7 An example of an electrode terminal block of a secondary battery according to a third embodiment of the present disclosure is shown.

[0036] Figure 8 Examples of pouch-type secondary batteries according to some embodiments of the present disclosure.

[0037] Figure 9 This is a flowchart of a method for manufacturing a secondary battery according to some embodiments of the present disclosure, which can describe the manufacturing process. Figure 1 The method for secondary batteries is shown in the figure.

[0038] Figure 10 This is a flowchart of a method for manufacturing electrode terminals according to some embodiments of the present disclosure.

[0039] Explanation of some figure labels

[0040] 10: Electrode connector

[0041] 11: First metal part; 12: Second metal part

[0042] 30: Roller pressing device

[0043] 100: Cylindrical secondary battery

[0044] 110: Shell

[0045] 111: Bottom 112: Sidewall

[0046] 120: Electrode assembly

[0047] 121: Negative electrode plate 122: Positive electrode plate

[0048] 123: Diaphragm; 124: Negative electrode connector

[0049] 126: First insulating board; 127: Second insulating board

[0050] 130: Center Sales

[0051] 140: Cover component

[0052] 141: Top plate; 142: Middle plate

[0053] 143: Insulation board; 144: Base plate

[0054] 800: Pouch-type secondary battery

[0055] 810: Electrode Assembly

[0056] 811: Negative electrode connector 812: Negative electrode plate

[0057] 814: Positive electrode plate; 816: Diaphragm

[0058] 822: Negative electrode lead; 824: Positive electrode lead

[0059] 826: Connector Film

[0060] 830: bag

[0061] 832: Sealing part Detailed Implementation

[0062] The 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 general or dictionary meanings, and should be interpreted as meanings and concepts consistent with the technical spirit of this disclosure, based on the principle that the inventor can be his / her own lexicographer to appropriately define terms and concepts for the best interpretation of his / her invention.

[0063] The embodiments described in this specification and the configurations illustrated in the accompanying drawings are merely some embodiments of this disclosure and do not represent all technical ideas, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications may exist to replace or modify the embodiments described herein at the time of filing this application.

[0064] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to," or "linked to" another element or layer, it may be directly on, connected to, or linked to the other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to," or "directly linked to" another element or layer, no intermediary element or layer is present. For example, when a first element is described as being "linked" or "connected" to a second element, the first element may be directly linked to or connected to the second element, or the first element may be indirectly linked to or connected to the second element via one or more intermediary elements.

[0065] In the accompanying drawings, the dimensions of various elements, layers, etc., may be enlarged for clarity. The same reference numerals denote the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated enumerated 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..." modify the entire list of elements, not individual elements, when preceding / following a list of elements. 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 denote 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 terms "use" and "be used" may be considered synonymous with the terms "utilize" and "be exploited," respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximations rather than terms of degree and are intended to describe the inherent variations in measured or calculated values ​​that would be recognized by one of ordinary skill in the art.

[0066] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, areas, layers, and / or segments, these elements, components, areas, layers, or segments should not be limited by these terms. These terms are used to distinguish one element, component, area, layer, or segment from another element, component, area, layer, or segment. Therefore, the first element, component, area, layer, or segment discussed below may be referred to as the second element, component, area, layer, or segment without departing from the teachings of the exemplary embodiments.

[0067] For ease of description, spatial relative terms, such as “below,” “under,” “down,” “above,” and “above,” are used herein to describe the relationship of one element or feature to another element or feature illustrated in the figures. It will be understood that, in addition to the orientations depicted in the figures, spatial relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “below” or “under” other elements or features will be oriented “above” or “above” other elements or features. Thus, the term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein should be interpreted accordingly.

[0068] The terminology used herein is for describing embodiments of this disclosure and is not intended to limit this disclosure. Unless the context clearly indicates otherwise, the singular form “a” as used herein is intended to include the plural form as well. It will be further understood that the term “comprising” as used in this specification indicates the presence of said features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0069] Furthermore, any numerical range disclosed and / or set forth herein is intended to include all subranges with the same numerical precision contained within the set forth range. For example, the range “1.0 to 10.0” is intended to include all subranges between the stated minimum value of 1.0 and the stated 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, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits contained herein, and any minimum numerical limit set forth in this specification is intended to include all higher numerical limits contained herein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly set forth any subranges contained within the range expressly set forth herein.

[0070] Referring to two compared elements, features, etc., as "identical" can mean that they are "substantially identical." Therefore, the phrase "substantially identical" can include situations in the art where the deviation is considered low, for example, a deviation of 5% or less. Additionally, when a parameter is described as uniform in a given region, this can mean that it is uniform in terms of average value.

[0071] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0072] Placing any element "above (or below)" or "above (below)" another element means that the arbitrary element can be configured to contact the upper (or lower) surface of the element, and the other element can also be located between the element and any element disposed on (or below) the element.

[0073] Additionally, 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.

[0074] Throughout this specification, unless otherwise stated, when “A and / or B” is mentioned, it means A, B, or A and B. That is, “and / or” includes any or all combinations of the listed items. Unless otherwise indicated, when “C to D” is mentioned, it means above C and below D.

[0075] Figure 1 Examples of cylindrical secondary batteries according to some embodiments of the present disclosure.

[0076] refer to Figure 1 A cylindrical lithium-ion secondary battery 100 according to one or more embodiments of the present disclosure may include a housing 110, an electrode assembly 120, and a cover assembly 140. Furthermore, in some embodiments, the cylindrical lithium-ion secondary battery 100 may include a center pin 130. Further, in the secondary battery 100 according to one or more embodiments of the present disclosure, the cover assembly 140 may also perform a current interruption operation and is therefore sometimes referred to as a current interruption device (CID).

[0077] The housing 110 may have the shape of a cylindrical can. The housing 110 may have a generally circular bottom 111 and cylindrical sidewalls 112 extending upwards (e.g., for a predetermined length) from the circumference (or perimeter) of the bottom 111. During the manufacturing process of the secondary battery 100, the top portion of the housing 110 is open. Therefore, during the assembly process of the secondary battery 100, the electrode assembly 120 and the center pin 130 can be inserted into the housing 110 along with the electrolyte. The housing 110 may be made of, for example, steel, stainless steel, aluminum, aluminum alloy, or equivalents thereof, but is not limited thereto.

[0078] Electrode assembly 120 may be housed within housing 110. Electrode assembly 120 may include a negative electrode plate 121 coated with a negative electrode active material (e.g., graphite, carbon, etc.) on a negative electrode current collector plate, a positive electrode plate 122 coated with a positive electrode active material (e.g., transition metal oxides such as LiCoO2, LiNiO2, LiMn2O4, etc.) on a positive electrode current collector plate, and a separator 123 located between the negative electrode plate 121 and the positive electrode plate 122 to prevent short circuits between them while allowing lithium ions to pass through. Furthermore, the negative electrode plate 121, the positive electrode plate 122, and the separator 123 may be wound into a generally cylindrical shape. In one embodiment, the negative electrode current collector may be made of copper (Cu) foil, the positive electrode current collector may be made of aluminum (Al) foil, and the separator may be made of polyethylene (PE) or polypropylene (PP), but the invention is not limited thereto.

[0079] The positive electrode for a rechargeable lithium battery may include a positive electrode current collector and a layer of positive electrode active material on the positive electrode 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 (e.g., an electrically conductive material).

[0080] For example, the positive electrode may further include components that can be used as a sacrificial positive electrode.

[0081] Based on a 100 wt% positive electrode active material layer, the amount of positive electrode active material can be from about 90 wt% to about 99.5 wt%. Based on a 100 wt% positive electrode active material layer, the amounts of binder and conductive material can be from about 0.5 wt% to about 5 wt%, respectively.

[0082] The binder is used to attach the positive electrode active material particles to each other and also to the current collector. Examples of binders may include polyvinyl alcohol, carboxymethyl cellulose, hydroxypropyl cellulose, diacetyl cellulose, polyvinyl chloride, carboxylated polyvinyl chloride, polyvinyl fluoride, polymers including ethylene oxide, polyvinylpyrrolidone, polyurethane, polytetrafluoroethylene, polyvinylidene fluoride, polyethylene, polypropylene, styrene-butadiene rubber, (meth)acrylated styrene-butadiene rubber, epoxy resin, (meth)acrylate resin, polyester resin, and nylon, etc., as non-limiting examples.

[0083] Conductive materials can be used to impart conductivity (e.g., electrical conductivity) to electrodes. Any material that does not cause chemical changes (e.g., does not cause undesirable chemical changes in rechargeable lithium batteries) and conducts electrons can be used in the battery. Examples of conductive materials can include: carbon-based materials such as natural graphite, artificial graphite, carbon black, acetylene black, Ketjen black, carbon fibers, carbon nanofibers, and carbon nanotubes; metallic materials containing copper, nickel, aluminum, silver, etc., in the form of metal powder or metal fibers; conductive polymers such as polyphenylene derivatives; or mixtures thereof.

[0084] Al foil can be used as a positive electrode current collector, but this disclosure is not limited thereto.

[0085] Furthermore, the negative electrode tab 124, which protrudes downward from the electrode assembly 120 and extends for a certain length (e.g., a suitable length), can be soldered to the negative electrode plate 121, and the positive electrode tab 10, which protrudes upward from the electrode assembly 120 and extends for a certain length (e.g., a suitable length), can be soldered to the positive electrode plate 122, but the reverse configuration is possible. Additionally, for example, the negative electrode tab 124 can be made of copper (Cu) or nickel (Ni), and the positive electrode tab 10 can be made of aluminum (Al), but this disclosure is not limited thereto.

[0086] Furthermore, the negative electrode tab 124 of the electrode assembly 120 can be soldered to the bottom 111 of the housing 110. Therefore, the housing 110 can be used as a negative electrode. Alternatively, the positive electrode tab 10 can be soldered to the bottom 111 of the housing 110, and in this embodiment, the housing 110 can be used as a positive electrode. Here, either the positive electrode tab 10 or the negative electrode tab 124 can electrically connect the electrode assembly 120 to the cover assembly 140.

[0087] Furthermore, the cover assembly 140 may be coupled to one end of the housing 110. For example, the secondary battery 100 may include a second insulating plate 127 coupled to the housing 110. The second insulating plate 127 has a first hole 127a at the center and a plurality of second holes 127b formed outside the center (e.g., located at the periphery of the center) and may be located between the electrode assembly 120 and the cover assembly 140. The second insulating plate 127 prevents the electrode assembly 120 from making electrical contact with the cover assembly 140. For example, the second insulating plate 127 prevents the negative electrode plate 121 of the electrode assembly 120 from making electrical contact with the cover assembly 140. If a large amount of gas is generated due to an abnormality of the secondary battery (or when a large amount of gas is generated due to an abnormality of the secondary battery), the first hole 127a allows the gas to move rapidly toward the cover assembly 140, and the second holes 127b allow the positive electrode tab 10 to penetrate (or extend through) and be soldered to the cover assembly 140. In addition, the remaining second holes 127b allow electrolyte to flow rapidly into the electrode assembly 120 during electrolyte injection.

[0088] Furthermore, the diameters of the first hole 126a of the first insulating plate 126 and the first hole 127a of the second insulating plate 127 are formed to be smaller than the diameter of the center pin 130, thereby preventing the center pin 130 from making electrical contact with the bottom 111 of the housing 110 or the cover assembly 140 due to external impact.

[0089] The center pin 130 has the shape of a hollow cylindrical tube and can be coupled to the center of the electrode assembly 120. The center pin 130 can be made of, for example, steel, stainless steel, aluminum, aluminum alloy, or polybutylene terephthalate, but this disclosure is not limited thereto. The center pin 130 suppresses (or prevents) deformation of the electrode assembly 120 during battery charging and discharging and serves as a channel for gases generated inside the secondary battery. Of course, in some embodiments, the center pin 130 may be omitted.

[0090] The cover assembly 140 may include a top plate 141, a middle plate 142, an insulating plate 143, and a bottom plate 144.

[0091] The intermediate plate 142 is located below the top plate 141 and may have a substantially flat shape.

[0092] When viewed from the bottom, the insulating plate 143 can be formed into an annular shape with a suitable width (e.g., a predetermined width). Furthermore, the insulating plate 143 insulates the intermediate plate 142 and the bottom plate 144 from each other. The insulating plate 143 can be positioned, for example, between the intermediate plate 142 and the bottom plate 144, and then ultrasonically welded, but this disclosure is not limited thereto.

[0093] In the event of an external short circuit or similar condition, the internal pressure within the secondary battery cell may increase. This increased pressure may trigger a current interruption device. For example, an external short circuit may cause current to flow within the secondary battery cell. As a result, side reactions and thermal runaway may occur within the secondary battery cell, potentially leading to an increase in internal pressure. When the internal pressure of the secondary battery cell rises, the current interruption device can activate, thereby placing the secondary battery cell in an insulated state. Alternatively, in the case of an external short circuit occurring in a low-resistance region, the electrode terminals can be cut to insulate the secondary battery cell.

[0094] When the current interruption device is the only device that places individual secondary battery cells in an insulated state, adjacent cells may be damaged. For example, when an external short circuit occurs in a high-resistance area, the current interruption device may not function until the internal pressure reaches and exceeds a predetermined threshold. In other words, the current interruption device may only function through rapid degradation of individual secondary battery cells or through the generation of a large amount of gas. In this case, the temperature of the secondary battery may increase, which could adversely affect adjacent cells and lead to damage to the battery pack.

[0095] In some embodiments of this disclosure, electrode tabs 10 are provided to prevent damage to adjacent secondary batteries before the temperature of the individual secondary battery cells reaches a high temperature. In one embodiment, electrode tabs 10 may include an alloy layer with a low melting point, which can induce an insulating state in electrode tabs 10 before current interruption devices activate. Therefore, the battery pack can be stabilized before the temperature of the individual secondary battery cells rises to a high temperature.

[0096] Reference Figures 2 to 10 Describe electrode connector 10 in detail.

[0097] Figure 2 This is a perspective view of the electrode terminals of a secondary battery according to a first embodiment of the present disclosure.

[0098] refer to Figure 2 According to some embodiments of the present disclosure, the electrode tab 10 can be electrically connected to the positive electrode plate 122 of the electrode assembly 120. In one embodiment, the electrode tab 10 can be a positive electrode tab. The positive electrode tab can be formed from a strip of metal and manufactured by including a metal material with excellent conductivity, such as an aluminum (Al) plate. Therefore, the first portion 11 containing the first metal and the second portion 12 containing the second metal can be plate-shaped. However, the present disclosure is not limited to this configuration.

[0099] In one embodiment, the electrode tab 10 may include a first portion 11 and a second portion 12 surrounding at least a portion of the first portion 11. For example, as... Figure 2 As illustrated, the length D1 of the first part 11 can be equal to or less than the length D2 of the second part 12. Here, the length of the electrode connector 10 refers to... Figure 2 The length extending in the Z-axis direction shown corresponds to the longitudinal direction of the electrode contact piece 10. That is, the Z-axis direction can be the direction in which the electrode contact piece 10 extends.

[0100] In one embodiment, the first portion 11 may be located at the center of the electrode tab 10, and all sides (surfaces) of the first portion 11 are surrounded by the second portion 12. In this embodiment, the length D1 of the first portion 11 may be less than the length D2 of the second portion 12. Furthermore, the width and thickness of the first portion 11 may be less than the width and thickness of the second portion 12.

[0101] In one embodiment, the melting point of the second metal may be higher than that of the first metal. For example, when the second metal is aluminum, its melting point may be 660°C, and the melting point of the first metal may be in the range of 50°C to 280°C. In one embodiment, the first metal may be an alloy comprising at least two of arsenic (As), lead (Pb), tin (Sn), cadmium (Cd), and indium (In). The second metal may be a metal comprising aluminum (Al). Therefore, as the temperature of the secondary battery increases, the first portion 11 may melt before the second portion 12, and high heat may be locally generated due to the high resistance occurring in the second portion 12, where the current path narrows. High heat may cause a short circuit in the electrode terminals 10. Therefore, the secondary battery cells can reach an insulating state before adjacent secondary battery cells are damaged.

[0102] Figure 3 Examples of methods for manufacturing electrode terminals for a secondary battery according to some embodiments of the present disclosure are provided.

[0103] refer to Figure 3 In part (a), a plate-shaped metal made of a first metal can be located between two plate-shaped metals each made of a second metal. Here, the electrode terminal 10 can be formed by performing a rolling process using a rolling device 30. A rolling process refers to a process in which metal material is fed between two rotating rollers to process the metal. In this disclosure, a rolling process is described as an example, but the method for manufacturing the electrode terminal 10 is not limited to the rolling process.

[0104] refer to Figure 3 Part (b) allows control of the rolling process so that the thickness L2 of the second part 12 located on the upper surface of the first part 11 is the same as the thickness L2 of the second part 12 located on the lower surface of the first part 11. Here, as... Figure 3 As depicted in part (b), the thickness L1 of the first part 11 and the thickness L2 of the second part 12 can be the lengths extending in the y-axis direction on the xy section of the electrode terminal 10. As a result, the first part 11 can be surrounded by the second part 12 and located at the center of the electrode terminal 10.

[0105] In one embodiment, the thickness L1 of the first portion 11 may be less than 30% of the total thickness of the electrode tab 10. In one embodiment, the thickness L1 of the first portion 11 and the thickness L2 of the second portion 12 located on the upper or lower surface of the first portion 11 may be in a 3:4 ratio. In another embodiment, the thickness L1 of the first portion 11 and the thickness L2 of the second portion 12 located on the upper or lower surface of the first portion 11 may be in a 2:5 ratio. The first portion 11 may be formed to have a thickness L1 sufficient to cause a short circuit in the electrode tab 10 when the first portion 11 melts due to the deterioration of the secondary battery.

[0106] In one embodiment, the width W1 of the first portion 11 relative to the center C of the electrode terminal 10 can be at least 75% of the width W2 of the electrode terminal 10. Here, as... Figure 3 As depicted in section (b), the width W1 of the first portion 11 and the width W2 of the electrode terminal 10 can be the lengths extending in the x-axis direction on the xy section of the electrode terminal 10. The first portion 11 can be made to have a width W1 that is sufficient to cause a short circuit in the electrode terminal 10 when the first portion 11 melts due to the deterioration of the secondary battery.

[0107] Figure 4 An example of a short-circuit process in the electrode terminals of a secondary battery according to an embodiment of the present disclosure is shown.

[0108] refer to Figure 4 In parts (a) and (b), the first part 11 melts when the temperature of the electrode terminal 10 rises to a temperature higher than the melting point of the first metal. For example, in the event of an event such as an external short circuit occurring in the secondary battery cell, high resistance and high heat may be locally generated in the secondary battery cell.

[0109] refer to Figure 4 In part (c), the first part 11, having a lower melting point than the second part 12, melts before the second part 12. Subsequently, as the first part 11 melts, the second part 12 may short-circuit. Therefore, the electrode terminal 10 may short-circuit. Here, the melted first part 11 can be discharged to the outside of the electrode terminal 10. In this way, the secondary battery cell can be placed in an insulated state, thereby minimizing damage to adjacent secondary battery cells.

[0110] As described above, according to embodiments of the present disclosure, the secondary battery may include electrode terminals 10 capable of short-circuiting. Therefore, damage to the battery pack can be minimized before the secondary battery cell undergoes internal degradation and before internal pressure increases.

[0111] Figure 5 and Figure 6Each of the electrode terminals of a secondary battery according to a second embodiment of the present disclosure is illustrated. In the following description, for convenience, the description will focus on... Figure 2 The differences between the embodiments described herein.

[0112] In one embodiment, at least one surface of the first portion 11 may be exposed to the outside of the electrode tab 10. (See reference...) Figure 5 The left side surface of the first portion 11 can be exposed to the outside of the electrode terminal 10 at the side surface of the electrode terminal 10. By exposing the left side surface of the first portion 11 at the left side surface of the electrode terminal 10, the second portion 12 can be easily short-circuited when the first portion 11 melts.

[0113] refer to Figure 6 The right side surface of the first portion 11 can be exposed to the outside of the electrode terminal 10 at the side surface of the electrode terminal 10. By exposing the right side surface of the first portion 11 at the right side surface of the electrode terminal 10, the second portion 12 can be easily short-circuited when the first portion 11 melts.

[0114] In one embodiment, the width W1 of the first portion 11 may be at least 75% of the total width W2 of the electrode terminal block 10. Thus, the first portion 11 may be made to have a width W1 that is sufficient to cause a short circuit in the electrode terminal block 10 when the first portion 11 melts due to the deterioration of the secondary battery.

[0115] like Figure 5 and Figure 6 As illustrated, when at least one surface of the first portion 11 is exposed to the outside of the electrode tab 10, the molten first portion 11 can be effectively discharged to the outside of the electrode tab 10.

[0116] Figure 7 An example of an electrode connection piece of a secondary battery according to a third embodiment of this disclosure is shown. In the following description, for convenience, the description will focus on... Figure 2 The differences between the embodiments described herein.

[0117] refer to Figure 7 At least a portion of the electrode contact 10 may include a first plate-shaped portion, a second plate-shaped portion, and a third plate-shaped portion. The first plate-shaped portion 11 may be made of a first metal, and the second plate-shaped portion 12 may be made of a second metal and disposed on the surface of the first plate-shaped portion 11. Furthermore, the third plate-shaped portion 12 may be made of a second metal and disposed on a second surface of the first plate-shaped portion 11 opposite to the first surface. Here, the side surface of the first plate-shaped portion 11 is exposed to the outside of the electrode contact 10.

[0118] In one embodiment, the thickness L1 of the first portion 11 may be less than 30% of the total thickness of the electrode terminal piece 10. In one embodiment, the thickness L1 of the first portion 11 and the thickness L2 of the second portion 12 disposed on the upper or lower surface of the first portion 11 may be in a 3:4 ratio. In another embodiment, the thickness L1 of the first portion 11 and the thickness L2 of the second portion 12 disposed on the upper or lower surface of the first portion 11 may be in a 2:5 ratio. The first portion 11 may be formed to have a thickness L1 sufficient to cause a short circuit in the electrode terminal piece 10 when the first portion 11 melts due to the deterioration of the secondary battery.

[0119] Figure 8 An example of a pouch-type secondary battery according to an embodiment of the present disclosure is given. In the following description, for convenience, the focus will be on... Figure 1 The differences between the embodiments described herein.

[0120] refer to Figure 8 The pouch-type secondary battery 800 includes an electrode assembly 810 and a pouch 830 for housing the electrode assembly 810.

[0121] The electrode assembly 810 includes a negative electrode plate 812 serving as a first electrode plate, a positive electrode plate 814 serving as a second electrode plate, and a diaphragm 816 situated therebetween. Further, the electrode assembly 810 may include a positive electrode tab 10 and a negative electrode tab 811. The negative electrode plate 812 may include a negative electrode tab 811 electrically connected to an uncoated portion of the negative electrode, and the positive electrode plate 814 may include a positive electrode tab 10 electrically connected to an uncoated portion of the positive electrode. The negative electrode tab 811 and the positive electrode tab 10 are respectively soldered to negative electrode leads 822 and positive electrode leads 824 of external terminals for electrical connection to the outside. A tab membrane 826 for insulation from the bag 830 is attached to the negative electrode leads 822 and the positive electrode leads 824.

[0122] The diaphragm 816 is made of a porous material and can be made of polyolefins such as polyethylene or polypropylene.

[0123] With the electrode assembly 810 housed in the bag 830, the sealing portions 832 at the edges of the bag 830 contact each other (e.g., the sealing portion 832 around the bottom portion of the bag 830 contacts the corresponding peripheral area of ​​the top portion (e.g., the cap) of the bag 830) to form a seal. This seal is performed with the terminal diaphragm 826 disposed between the sealing portions 832. Figure 8 As shown, the form in which the terminal block 826 is attached to each of the negative electrode lead 822 and the positive electrode lead 824 is defined as a "separable terminal block 826" (e.g., such a sealing structure is referred to as a separable sealing structure).

[0124] According to some embodiments of this disclosure, the electrode connector 10 can be electrically connected to the positive electrode plate 814 of the electrode assembly 810. That is, the electrode connector 10 can be a positive electrode connector.

[0125] In one embodiment, the electrode tab 10 may protrude to the outside of the bag 830. The positive electrode tab, formed from a strip of metal, can be manufactured using a metallic material comprising excellent conductivity, such as an aluminum (Al) plate. Therefore, both the first and second portions may be plate-shaped. However, this disclosure is not limited to such embodiments.

[0126] In some embodiments of this disclosure, electrode tabs 10 are provided to prevent damage to adjacent secondary batteries before the temperature of a single secondary battery cell reaches a high temperature. As described above in the embodiments, electrode tabs 10 may include an alloy layer with a low melting point, which can induce an insulating state in the electrode tabs 10 before the current interruption device activates. Therefore, the stability of the battery pack can be ensured before the temperature of the secondary battery cell rises to a high temperature.

[0127] Electrode terminals 10 can be used not only for Figure 1 Cylindrical secondary battery 100 and Figure 8 The pouch-type secondary battery can also be used in prismatic and coin-type secondary batteries. For example, the electrode terminal 10 according to an embodiment of the present disclosure can be used as the positive terminal terminal of a prismatic secondary battery and the positive electrode terminal terminal of a coin-type secondary battery.

[0128] Figure 9 This is a flowchart of a method for manufacturing a secondary battery according to an embodiment of the present disclosure. The method may involve manufacturing... Figure 1 The method of the secondary battery 100 shown.

[0129] refer to Figure 9 Method S900 can begin by assembling an electrode assembly including a positive electrode plate, a diaphragm, and a negative electrode plate within a housing (step S910).

[0130] The electrode assembly and the cover assembly can be electrically connected using electrode tabs (step S920). Here, the electrode tabs can be connected to the positive electrode plate of the electrode assembly. That is, the electrode tabs can be positive electrode tabs. The positive electrode tabs formed from strip metal plates can be manufactured using a metal material including a plate of aluminum (Al) with excellent conductivity. As described above, the electrode tabs can include a first portion comprising a first metal and a second portion comprising a second metal surrounding at least a portion of the first portion.

[0131] The cover assembly can be attached to one end of the housing (step S930).

[0132] In one embodiment, the melting point of the second metal can be higher than that of the first metal. For example, when the second metal is aluminum, its melting point can be 660°C, and the melting point of the first metal can be in the range of 50°C to 280°C. For example, the first metal can be an alloy comprising at least two of arsenic (As), lead (Pb), tin (Sn), cadmium (Cd), and indium (In). The second metal can be a metal comprising aluminum (Al). Therefore, as the temperature of the secondary battery rises, the first metal melts before the second metal, which may cause a short circuit in the electrode terminals. Thus, the secondary battery cells can reach an insulating state before adjacent cells are damaged.

[0133] like Figure 2 As illustrated, in one embodiment, the length of the first portion may be equal to or less than the length of the electrode tab. Here, the length of the electrode tab may refer to its length extending in the Z-axis direction.

[0134] In one embodiment, the first portion may be located at the center of the electrode tab, and all surfaces of the first portion are surrounded by the second portion. In another example, some surfaces of the first portion may be exposed to the outside of the electrode tab.

[0135] In one embodiment, the thickness of the first portion may be less than 30% of the total thickness of the electrode tab. In one embodiment, the thickness of the first portion and the thickness of the second portion located on the upper or lower surface of the first portion may be in a 3:4 ratio. In another embodiment, the thickness of the first portion and the thickness of the second portion located on the upper or lower surface of the first portion may be in a 2:5 ratio. The first portion may be made to have a thickness sufficient to cause a short circuit in the electrode tab when the first portion melts due to the deterioration of the secondary battery.

[0136] In one embodiment, the width of the first portion relative to the center C of the electrode terminal piece can be at least 75% of the width of the electrode terminal piece. Here, the width of the first portion and the width of the second portion can be the length extending in the x-axis direction on the xy section of the electrode terminal piece. The first portion can be made to have a width sufficient to cause a short circuit in the electrode terminal piece when the first portion melts due to the deterioration of the secondary battery.

[0137] In one embodiment, the first portion may melt when the temperature of the electrode terminals rises above the melting point of the first metal. For example, high resistance and high heat may be locally generated in a secondary battery cell when an event such as an external short circuit occurs.

[0138] Because the first metal has a lower melting point than the second metal, the first portion may melt before the second portion. Subsequently, as the first portion melts, the second portion may short-circuit. That is, the electrode terminals may short-circuit. The molten first portion can be discharged outside the electrode terminals. In this way, the secondary battery cell can be guided to an insulated state, thereby minimizing damage to adjacent secondary battery cells.

[0139] As described above, according to some embodiments of this disclosure, a secondary battery may include electrode tabs capable of short-circuiting, thereby minimizing damage to the battery pack before individual secondary battery cells undergo internal degradation and increased internal pressure.

[0140] Figure 10 This is a flowchart of a method for manufacturing electrode terminals according to some embodiments of the present disclosure.

[0141] refer to Figure 10 Method S1000 can begin by preparing a first plate-shaped portion made of a first metal (step S1010). Simultaneously, two second plate-shaped portions can be prepared, each of the two second plate-shaped portions being made of a second metal (step S1020).

[0142] Subsequently, the first plate-shaped portion can be positioned between the two second plate-shaped portions (step S1030).

[0143] Subsequently, a rolling process can be performed on the first plate-shaped portion and the two second plate-shaped portions (step S1040). During the rolling process, the thickness of the second portion located on the upper surface of the first portion and the thickness of the second portion located on the lower surface of the first portion can be the same.

[0144] Although the present disclosure has been described above with respect to embodiments thereof, the present disclosure is not limited thereto. Various modifications and variations may be made thereto by those skilled in the art within the spirit of the present disclosure.

Claims

1. An electrode assembly, comprising: Positive electrode plate; Negative electrode plate; A diaphragm located between the positive electrode plate and the negative electrode plate; as well as The electrode terminals are electrically connected to the positive electrode plate. The electrode terminal includes a first portion containing a first metal and a second portion containing a second metal that at least partially surrounds the first portion.

2. The electrode assembly according to claim 1, wherein, The melting point of the second metal is higher than that of the first metal.

3. The electrode assembly according to claim 2, wherein, The melting point of the first metal is in the range of 50°C to 280°C.

4. The electrode assembly of claim 2, wherein the first metal is an alloy comprising at least two of arsenic, lead, tin, cadmium and indium, and the second metal is a metal comprising aluminum.

5. The electrode assembly of claim 1, wherein the first portion is located at the center of the electrode tab, and all surfaces of the first portion are surrounded by the second portion.

6. The electrode assembly of claim 1, wherein at least one surface of the first portion is exposed to the outside of the electrode tab.

7. The electrode assembly according to claim 1, wherein the electrode terminals comprise: The first plate-shaped portion is made of the first metal; The second plate-shaped portion is made of the second metal and disposed on the first surface of the first plate-shaped portion; as well as The third plate-shaped portion, made of the second metal, is disposed on the second surface of the first plate-shaped portion opposite to the first surface, and In this embodiment, a pair of side surfaces of the first plate-shaped portion are exposed to the outside of the electrode terminals.

8. The electrode assembly according to claim 1, wherein, The thickness of the first portion is less than 30% of the thickness of the electrode terminal piece.

9. The electrode assembly according to claim 1, wherein, The width of the first portion is at least 75% of the width of the electrode tab.

10. The electrode assembly according to claim 1, wherein, The electrode terminals are configured such that when the temperature of the electrode terminals rises to a temperature higher than the melting point of the first metal, the first portion melts, and then the second portion is short-circuited.

11. The electrode assembly of claim 10, wherein, The electrode tab is configured such that the molten first portion is discharged to the outside of the electrode tab.

12. A method of manufacturing the electrode assembly according to claim 1, wherein, The electrode terminal is formed by positioning a first plate-shaped portion made of the first metal between two second plate-shaped portions and performing a rolling process on the first plate-shaped portion and the two second plate-shaped portions, each of the two second plate-shaped portions being made of the second metal.

13. The method of manufacturing the electrode assembly according to claim 12, wherein, In the rolling process, the thickness of the second part located on the upper surface of the first part and the thickness of the second part located on the lower surface of the first part are the same.

14. A method for manufacturing a secondary battery, the method comprising: The electrode assembly is housed within the casing; The electrode terminals and the cover assembly are connected to the electrode assembly; as well as Connect the cover assembly to one end of the housing. The electrode terminal includes a first portion containing a first metal and a second portion containing a second metal that at least partially surrounds the first portion.

15. The method of claim 14, wherein the electrode tab is manufactured by the following steps: Prepare a first plate-shaped portion made of the first metal; Prepare two second plate-shaped portions, each of which is made of the second metal; Positioning the first plate-shaped portion between the two second plate-shaped portions; and A rolling process is performed on the first plate-shaped portion and the two second plate-shaped portions.

16. The method of claim 14, wherein the melting point of the second metal is higher than that of the first metal.

17. The method of claim 14, wherein the first metal is an alloy comprising at least two of arsenic, lead, tin, cadmium and indium, and the second metal is a metal comprising aluminum.

18. The method of claim 14, wherein the first portion is located at the center of the electrode tab, and all surfaces of the first portion are surrounded by the second portion.

19. The method of claim 14, wherein at least one surface of the first portion is exposed to the outside of the electrode tab.

20. The method of claim 15, wherein, The execution of the rolling process includes: The thickness of the second part located on the upper surface of the first part and the thickness of the second part located on the lower surface of the first part are controlled to be the same.

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