Secondary battery and method of manufacturing strip terminal

Abstract

The invention relates to a secondary battery and a method of manufacturing a strip terminal. The secondary battery includes: an electrode assembly; a case accommodating the electrode assembly; and a strip-shaped terminal including: a conductor portion connected to the electrode assembly and extending outward; a foamed part surrounding the conductor part and including foamed particles foamed under a predetermined temperature condition; and an adhesive layer surrounding the foaming portion and bonded to the case.

Description

Technical Field

[0001] An embodiment of the present disclosure relates to a pouch-type secondary battery. Background Art

[0002] Lithium ion secondary batteries are used as power sources for hybrid vehicles or electric vehicles and portable electronic devices due to, for example, high operating voltage and high energy density per unit weight.

[0003] The above information disclosed in this Background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not constitute the prior art. Summary of the invention

[0004] An embodiment is directed to a secondary battery, which includes: an electrode assembly; a shell that accommodates the electrode assembly; and a strip terminal, including: a conductor portion that is connected to the electrode assembly and extends outward; a foaming portion that surrounds the conductor portion and contains foamed particles that are foamed under predetermined temperature conditions; and an adhesive layer that surrounds the foaming portion and is bonded to the shell.

[0005] The foamed portion may at least partially surround the conductor portion.

[0006] The foamed portion may completely surround the conductor portion.

[0007] The shell may include: a lower shell having a concave portion for accommodating the electrode assembly; and an upper shell covering the lower shell, the lower shell and the upper shell may be thermally bonded along a platform portion of the lower shell and a platform portion of the upper shell, the conductor portion may extend outward between the lower shell and the upper shell, and the adhesive layer may include: a lower adhesive layer between the foaming portion and the platform portion of the lower shell; and an upper adhesive layer between the foaming portion and the platform portion of the upper shell.

[0008] The heat required for foaming the foamed particles may be greater than the heat required for thermally combining the lower shell and the upper shell.

[0009] The lower adhesive layer and the upper adhesive layer may each have a width greater than a width of the foaming part.

[0010] The lower adhesive layer and the upper adhesive layer may contact each other at opposite ends of the strip terminal in a width direction.

[0011] The strip terminal may further include a foaming portion extension extending from the foaming portion to opposite ends of the strip terminal in the width direction, and the lower adhesive layer and the upper adhesive layer may be spaced apart from each other by the foaming portion extension at the opposite ends of the strip terminal in the width direction.

[0012] Opposite ends of the foaming portion extension in the width direction may coincide with opposite ends of the lower adhesive layer and the upper adhesive layer in the width direction.

[0013] The strip terminal may further include a heat-resistant layer between the foaming portion and the adhesive layer.

[0014] The heat-resistant layer may be made of a material having a higher melting point than that of the adhesive layer.

[0015] The shell may include: a lower shell having a concave portion for accommodating the electrode assembly; and an upper shell covering the lower shell, the lower shell and the upper shell may be thermally bonded along the platform portion of the lower shell and the platform portion of the upper shell, the conductor portion may extend outward between the lower shell and the upper shell, the adhesive layer may include: a lower adhesive layer, between the foaming portion and the platform portion of the lower shell; and an upper adhesive layer, between the foaming portion and the platform portion of the upper shell, and the heat-resistant layer may include: a lower heat-resistant layer, between the foaming portion and the lower adhesive layer; and an upper heat-resistant layer, between the foaming portion and the upper adhesive layer.

[0016] The heat required for foaming the foamed particles may be greater than the heat required for thermally combining the lower shell and the upper shell.

[0017] The lower adhesive layer and the upper adhesive layer and the lower heat-resistant layer and the upper heat-resistant layer may each have a width greater than a width of the foamed portion.

[0018] The lower heat-resistant layer and the upper heat-resistant layer may contact each other at opposite ends of the strip terminal in a width direction.

[0019] The strip terminal may further include a foaming portion extension extending from the foaming portion to opposite ends of the strip terminal in the width direction, and the lower heat-resistant layer and the upper heat-resistant layer may be separated from each other by the foaming portion extension at the opposite ends of the strip terminal in the width direction.

[0020] Opposite ends of the foamed portion extension in the width direction may coincide with opposite ends of the lower adhesive layer and the upper adhesive layer in the width direction and opposite ends of the lower heat-resistant layer and the upper heat-resistant layer in the width direction.

[0021] The foaming particles may include azodicarbonamide (ADCA), 4,4′-oxybis(benzenesulfonylhydrazide) (OBSH), or N,N′-dinitrosopentamethylenetetramine (DPT).

[0022] An embodiment is directed to a method for manufacturing a strip terminal, the method comprising: preparing and placing a member for forming a lower adhesive layer to be elongated in a width direction; placing a material for forming a foaming portion and a foaming portion extension on the member for forming the lower adhesive layer; placing conductor portions spaced apart at regular intervals in the width direction on the material for forming the foaming portion and the foaming portion extension; placing an additional material for forming the foaming portion and the foaming portion extension on the material for forming the foaming portion and the foaming portion extension and the conductor portion; placing a member for forming an upper adhesive layer on the additional material for forming the foaming portion and the foaming portion extension; and cutting the member for forming the lower adhesive layer, the material for forming the foaming portion and the foaming portion extension, the additional material for forming the foaming portion and the foaming portion extension, and the member for forming the upper adhesive layer at regular intervals along the width direction in the space between the conductor portions spaced apart at regular intervals along the width direction.

[0023] An embodiment relates to a method for manufacturing a strip terminal, the method comprising: preparing and placing a member for forming a lower adhesive layer to be elongated in a width direction; placing a material for forming a lower heat-resistant layer on the member for forming the lower adhesive layer; placing a material for forming a foaming portion and a foaming portion extension on the material for forming the lower heat-resistant layer; placing conductor portions spaced at regular intervals in the width direction on the material for forming the foaming portion and the foaming portion extension; placing an additional material for forming the foaming portion and the foaming portion extension on the material for forming the foaming portion and the foaming portion extension and the conductor portion; A material for forming an upper heat-resistant layer is placed on the additional material for forming the foaming portion and the foaming portion extension; a member for forming an upper adhesive layer is placed on the material for forming the upper heat-resistant layer; and the member for forming the lower adhesive layer, the material for forming the lower heat-resistant layer, the material for forming the foaming portion and the foaming portion extension, the additional material for forming the foaming portion and the foaming portion extension, the material for forming the upper heat-resistant layer, and the member for forming the upper adhesive layer are cut at regular intervals along the width direction in the space between the conductor portions spaced at regular intervals along the width direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Features will become apparent to those skilled in the art by describing in detail exemplary embodiments with reference to the accompanying drawings, in which:

[0025] Figure 1 is a schematic diagram of a secondary battery according to a first embodiment of the present disclosure;

[0026] Figure 2 For along Figure 1 A cross-sectional view taken along line II-II in FIG.

[0027] Figure 3 is a cross-sectional view of a first strip-shaped terminal of a secondary battery according to a second embodiment of the present disclosure, showing Figure 2 The corresponding part in ;

[0028] Figure 4 A process of manufacturing a first strip-shaped terminal of a secondary battery according to a second embodiment of the present disclosure is shown;

[0029] Figure 5 is a cross-sectional view of a first strip-shaped terminal of a secondary battery according to a third embodiment of the present disclosure, showing Figure 2 the corresponding part of

[0030] Figure 6 is a cross-sectional view of a first strip-shaped terminal of a secondary battery according to a fourth embodiment of the present disclosure, showing Figure 2 The corresponding part in . DETAILED DESCRIPTION

[0031] Example embodiments will now be described more fully hereinafter with reference to the accompanying drawings; however, they may be implemented in different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey exemplary implementations to those skilled in the art.

[0032] In the drawings, the dimensions of layers and regions may be exaggerated for clarity of illustration. It will also be understood that when a layer or element is referred to as being "on" another layer or element, it can be directly on the other layer or element, or there may be intervening layers. Further, it will be understood that when a layer is referred to as being "under" another layer, it can be directly under the other layer, and there may also be one or more intervening layers. In addition, it will be understood that when a layer is referred to as being "between" two layers, it can be the only layer between the two layers, or there may also be one or more intervening layers. The same reference numerals refer to the same elements throughout.

[0033] As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, it will be understood that when element A is referred to as being "connected to" element B, element A may be directly connected to element B, or an intervening element C may exist between them such that element A and element B are indirectly connected to each other.

[0034] The terms used herein are only used for the purpose of describing specific embodiments and are not intended to limit the present disclosure. As used herein, the singular form is intended to also include the plural form, unless the context clearly indicates otherwise. It will be further understood that the terms "include" and / or "comprise" when used in this specification specify the presence of the described features, numbers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, parts and / or groups thereof.

[0035] It will be understood that although the terms first, second, etc. may be used in this article to describe various components, elements, regions, layers and / or sections, these components, elements, regions, layers and / or sections should not be limited by these terms. These terms are only used to distinguish one component, element, region, layer and / or section from another component, element, region, layer and / or section. Therefore, for example, the first component, first element, first region, first layer and / or first section discussed below may be referred to as the second component, second element, second region, second layer and / or second section without departing from the teachings of the present invention.

[0036] For ease of description, spatially relative terms (such as "below," "below," "below," "above," "on," etc.) may be used herein to describe the relationship of one element or feature to another element or feature as illustrated in the figures. It will be understood that spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if an element or feature in a figure is flipped, an element described as being "below" or "beneath" another element or feature would then be oriented "on" or "above" the other element or feature. Thus, the exemplary term "below" may encompass both above and below orientations.

[0037] Figure 1 is a schematic diagram of a secondary battery 100 according to a first embodiment of the present disclosure.

[0038] Figure 2 For along Figure 1 For reference, Figure 2 The first strip terminal 130 is shown. As will be described later, the second strip terminal 140 may have the same structure as the first strip terminal 130, and thus will be Figure 2 The second strip terminal 140 is described in detail without separately attaching a diagram of the second strip terminal 140. Figure 2 In FIG. 1 , reference numerals in parentheses refer to reference numerals of components of the second strip-shaped terminal 140 .

[0039] refer to Figure 1, a secondary battery 100 according to the first embodiment of the present disclosure may include an electrode assembly 110 , a case 120 , a first strip terminal 130 , and a second strip terminal 140 .

[0040] The electrode assembly 110 may include a first electrode plate 111 , a second electrode plate 112 , and a separator 113 .

[0041] The first electrode plate 111 may be one of a negative electrode plate and a positive electrode plate. In one embodiment, if the first electrode plate 111 is a negative electrode plate, the first electrode plate 111 may include a coated portion (negative electrode coated portion) and an uncoated portion (negative electrode uncoated portion), in which an active material (negative electrode active material) is coated on a substrate (negative electrode substrate) formed of a thin conductive metal plate (e.g., copper foil or nickel foil or copper mesh or nickel mesh), and an uncoated portion (negative electrode uncoated portion) in which the negative electrode active material is not coated. The negative electrode active material may be made of, for example, a carbon-based material, Si, Sn, tin oxide, a tin alloy composite, a transition metal oxide, a lithium metal nitrite, or a metal oxide. The first electrode plate 111 may have a first electrode tab 111A. The first electrode tab 111A may be formed independently of the negative electrode uncoated portion and welded to the negative electrode uncoated portion, or may be formed integrally with the negative electrode uncoated portion by stamping the negative electrode uncoated portion.

[0042] The second electrode plate 112 may be the other of the negative electrode plate and the positive electrode plate. In one embodiment, if the second electrode plate 112 is a positive electrode plate, the second electrode plate 112 may include a coated portion (positive electrode coated portion) and an uncoated portion (positive electrode uncoated portion), in which the active material (positive electrode active material) is coated on a substrate (positive electrode substrate) formed by a thin conductive metal plate (e.g., aluminum foil or aluminum mesh), and the positive electrode active material is not coated in the uncoated portion (positive electrode uncoated portion). The positive electrode active material may be made of a composite metal oxide such as a chalcogenide (e.g., LiCoO2, LiMn2O4, LiNiO2, or LiNiMnO2). The second electrode plate 112 may have a second electrode tab 112A. The second electrode tab 112A may be formed independently of the positive electrode uncoated portion and welded to the positive electrode uncoated portion, or may be formed integrally with the positive electrode uncoated portion by stamping the positive electrode uncoated portion.

[0043] The separator 113 may be between the first electrode plate 111 and the second electrode plate 112 and may serve to prevent a short circuit between the first electrode plate 111 and the second electrode plate 112. The separator 113 may be made of, for example, polyethylene, polypropylene, or a porous copolymer of polyethylene and polypropylene.

[0044] The electrode assembly 110 may be formed by arranging the first electrode plate 111, the separator 113, the second electrode plate 112, and the separator 113 in this order and then winding in a so-called core form, or may be formed by repeatedly stacking the first electrode plate 111, the separator 113, the second electrode plate 112, and the separator 113. In one embodiment, the first electrode tab 111A may be aligned on one side of the electrode assembly 110, and the second electrode tab 112A may be aligned on the other side of the electrode assembly 110.

[0045] The case 120 may be formed in a pouch shape. In one embodiment, the case 120 may include a lower case 120-1 having a concave portion to accommodate the electrode assembly 110 and an upper case 120-2 covering the lower case 120-1.

[0046] The lower case 120-1 and the upper case 120-2 may be formed as a multilayer structure including an inner insulating layer 121, an outer insulating layer 122, and a metal layer 123. For example, both the lower case 120-1 and the upper case 120-2 may be individually formed of a multilayer structure and may include an inner insulating layer 121, an outer insulating layer 122, and a metal layer 123, respectively.

[0047] The inner insulating layer 121 may be a portion of the inner surface of the housing 120 and may be made of a material that does not react with the electrolyte and has insulating properties and thermal bonding properties, such as cast polypropylene (CPP). In one embodiment, the inner insulating layer 121 may be made of a material that has thermal bonding properties when exposed to at least 100° C. for about 2 to 3 seconds. For example, the inner insulating layer 121 may be made of a material that can be thermally bonded if exposed to at least 100° C. for about 2 to 3 seconds.

[0048] The outer insulating layer 122 is a portion of the outer surface of the housing 120 and may be made of an insulating material such as nylon, polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polybutylene naphthalate (PBN), etc.

[0049] Metal layer 123 may be between inner insulating layer 121 and outer insulating layer 122 to help prevent moisture and oxygen from entering from the outside and prevent electrolyte from leaking from the inside while maintaining the mechanical strength of case 120. Metal layer 123 may be made of, for example, aluminum.

[0050] The lower case 120 - 1 and the upper case 120 - 2 may be separately formed, or may be integrally connected at one side and folded such that the upper case 120 - 2 covers the lower case 120 - 1 .

[0051] In one embodiment, the lower housing 120 - 1 and the upper housing 120 - 2 may be thermally bonded along the periphery. The thermally bonded periphery may be referred to as a platform portion T.

[0052] The first strip-shaped terminal 130 may be led out from the electrode assembly 110. For example, the first strip-shaped terminal 130 may extend from the electrode assembly 110. Figure 2 The first strip terminal 130 may include a first conductor portion 131 , a first foaming portion 132 , a first lower adhesive layer 133 , and a first upper adhesive layer 134 .

[0053] The first conductor portion 131 may be welded to the first electrode tab 111A of the first electrode plate 111 of the electrode assembly 110, and may extend outward between the lower housing 120-1 and the upper housing 120-2. The first conductor portion 131 may be made of, for example, copper, copper alloy, nickel, nickel alloy, nickel-plated copper, etc. In one embodiment, if the first conductor portion 131 is made of nickel, the first conductor portion 131 may have a thermal conductivity of approximately 70W / mK to 80W / mK, and, for example, if the first conductor portion 131 has a thickness of 80μm, a width of 50mm, and a length of 40mm, the first conductor portion 131 may have a resistance of approximately 0.7mΩ to 0.8mΩ. In this case, when an overcurrent of 25A is applied for approximately 90 seconds, it is observed that the first conductor portion 131 generates heat of approximately 150°C to 160°C.

[0054] The first foaming portion 132 may at least partially surround the first conductor portion 131. Figure 2 , the first foaming portion 132 is illustrated as completely surrounding the first conductor portion 131. In one embodiment, the first foaming portion 132 may be at a position corresponding to the platform portion T. The first foaming portion 132 may include foaming particles that foam under predetermined temperature conditions. If the secondary battery 100 is exposed to high temperature, the electrolyte may evaporate and gas may be generated, so the electrode assembly 110 may be improperly deformed, and in severe cases, fire may occur. Here, the predetermined temperature condition refers to a condition in which the foaming particles may first foam before reaching this condition. In one embodiment, the foaming particles may be made of a material that can foam if exposed to at least 100°C for more than 10 seconds, and may include, for example, azodicarbonamide (ADCA), 4,4'-oxybis(benzenesulfonylhydrazide) (OBSH) and / or N,N'-dinitrosopentamethylenetetramine (DPT). In one embodiment, the heat required for the foaming particles to foam may be greater than the heat required for thermal bonding of the inner insulating layer 121 of the housing 120.

[0055] The first lower adhesive layer 133 may have a width greater than the width of the first conductor portion 131 and the width of the first foaming portion 132 (e.g., further extending in the X direction), and may be between the first foaming portion 132 and the platform portion T of the lower housing 120-1. In addition, the first lower adhesive layer 133 may be bonded and fixed to the platform portion T of the lower housing 120-1. In one embodiment, in the process of thermally bonding the lower housing 120-1 and the upper housing 120-2 along the platform portion T, the first lower adhesive layer 133 may be thermally bonded to the platform portion T of the lower housing 120-1. The first lower adhesive layer 133 may be made of a material having insulating properties and relatively low thermal conductivity (e.g., a material having a thermal conductivity of approximately 0.1W / mK to 0.2W / mK). In one embodiment, the first lower adhesive layer 133 may be made of polypropylene (PP). Therefore, if thermal bonding is performed as described above, heat may be transferred to the first foaming portion 132 through the first lower adhesive layer 133, thereby preventing the foaming particles from foaming.

[0056] The first upper adhesive layer 134 may be formed in the same configuration as the first lower adhesive layer 133. That is, the first upper adhesive layer 134 may have a width greater than the width of the first conductor portion 131 and the width of the first foaming portion 132, and may be between the first foaming portion 132 and the platform portion T of the upper housing 120-2. In addition, the first upper adhesive layer 134 may be bonded and fixed to the platform portion T of the upper housing 120-2. In one embodiment, in the process of thermally bonding the lower housing 120-1 and the upper housing 120-2 along the platform portion T, the first upper adhesive layer 134 may be thermally bonded to the platform portion T of the upper housing 120-2. The first upper adhesive layer 134 may be made of a material having insulating properties and relatively low thermal conductivity (e.g., a material having a thermal conductivity of approximately 0.1W / mK to 0.2W / mK). In one embodiment, the first upper adhesive layer 134 may be made of polypropylene (PP). Therefore, as described above, if thermally bonded, heat may be transferred to the first foaming portion 132 through the first upper adhesive layer 134 , thereby preventing the foaming particles from foaming.

[0057] The second strip-shaped terminal 140 may be formed in the same configuration as the first strip-shaped terminal 130. Figure 2 , will refer to Figure 2 Reference numerals in parentheses describe the second strip-shaped terminals 140 .

[0058] The second strip terminal 140 may be led out from the electrode assembly 110. For example, the second strip terminal 140 may extend from the electrode assembly 110. In one embodiment, the second strip terminal 140 may include a second conductor portion 141, a second foaming portion 142, a second lower adhesive layer 143, and a second upper adhesive layer 144.

[0059] The second conductor portion 141 may be welded to the second electrode tab 112A of the second electrode plate 112 of the electrode assembly 110, and may extend outward between the lower housing 120-1 and the upper housing 120-2. The second conductor portion 141 may be made of, for example, aluminum or an aluminum alloy. In one embodiment, if the second conductor portion 141 is made of aluminum, the second conductor portion 141 may have a thermal conductivity of approximately 200W / mK to 210W / mK, and, for example, if the second conductor portion 141 has a thickness of 80μm, a width of 50mm, and a length of 40mm, the second conductor portion 141 may have a resistance of approximately 0.2mΩ to 0.3mΩ. In this case, when an overcurrent of 25A is applied for approximately 90 seconds, it is observed that the second conductor portion 141 generates heat of approximately 90°C to 100°C.

[0060] The second foaming portion 142 may at least partially surround the second conductor portion 141. Figure 2 , the second foaming portion 142 is illustrated as completely surrounding the second conductor portion 141. In one embodiment, the second foaming portion 142 may be at a position corresponding to the platform portion T. The second foaming portion 142 may include foaming particles that foam under predetermined temperature conditions. If the secondary battery 100 is exposed to high temperatures, the electrolyte may evaporate and gas may be generated, so the electrode assembly 110 may be improperly deformed, and in severe cases, fire may occur. Here, the predetermined temperature condition refers to a condition in which the foaming particles may first foam before reaching this condition. In one embodiment, the foaming particles may be made of a material that can foam if exposed to at least 100°C for more than 10 seconds, and may include, for example, ADCA, OBSH and / or DPT. In one embodiment, the heat required for the foaming particles to foam may be greater than the heat required for thermal bonding of the internal insulating layer 121 of the shell 120.

[0061] The second lower adhesive layer 143 may have a width greater than that of the second conductor portion 141 and the second foaming portion 142 (e.g., further extending in the X direction), and may be between the second foaming portion 142 and the platform portion T of the lower housing 120-1. In one embodiment, the second lower adhesive layer 143 may be bonded and fixed to the platform portion T of the lower housing 120-1. In one embodiment, in the process of thermally bonding the lower housing 120-1 and the upper housing 120-2 along the platform portion T, the second lower adhesive layer 143 may be thermally bonded to the platform portion T of the lower housing 120-1. The second lower adhesive layer 143 may be made of a material having insulating properties and relatively low thermal conductivity (e.g., a material having a thermal conductivity of approximately 0.1W / mK to 0.2W / mK). In one embodiment, the second lower adhesive layer 143 may be made of polypropylene. Therefore, as described above, if thermally bonded, heat may be transferred to the second foaming portion 142 through the second lower adhesive layer 143, thereby preventing the foaming particles from foaming.

[0062] The second upper adhesive layer 144 may be formed in the same configuration as the second lower adhesive layer 143. That is, the second upper adhesive layer 144 may be formed to have a width greater than the width of the second conductor portion 141 and the width of the second foaming portion 142, and may be between the second foaming portion 142 and the platform portion T of the upper housing 120-2. In one embodiment, the second upper adhesive layer 144 may be bonded and fixed to the platform portion T of the upper housing 120-2. In one embodiment, in the process of thermally bonding the lower housing 120-1 and the upper housing 120-2 along the platform portion T, the second upper adhesive layer 144 may be thermally bonded to the platform portion T of the upper housing 120-2. The second upper adhesive layer 144 may be made of a material having insulating properties and relatively low thermal conductivity (e.g., a material having a thermal conductivity of approximately 0.1W / mK to 0.2W / mK). In one embodiment, the second upper adhesive layer 144 may be made of polypropylene. Therefore, as described above, if thermally bonded, heat may be transferred to the second foaming portion 142 through the second upper adhesive layer 144 , thereby preventing the foaming particles from foaming.

[0063] Figure 3 is a cross-sectional view of a first strip terminal 230 of a secondary battery according to a second embodiment of the present disclosure, showing Figure 2 The corresponding part in .

[0064] Figure 4 A process of manufacturing the first strip terminal 230 of the secondary battery according to the second embodiment of the present disclosure is shown.

[0065] The secondary battery according to the second embodiment of the present disclosure may include an electrode assembly, a housing, a first strip-shaped terminal 230, and a second strip-shaped terminal. However, the electrode assembly and the housing of the secondary battery according to the second embodiment of the present disclosure may have the same configuration as the electrode assembly 110 and the housing 120 of the secondary battery 100 according to the first embodiment of the present disclosure. Therefore, repeated explanations thereon will be omitted.

[0066] By comparing reference Figure 2 and Figure 3 , the difference is that, although the first foaming portion 132 of the first strip terminal 130 of the secondary battery 100 according to the first embodiment of the present disclosure may surround the first conductor portion 131 and the first lower adhesive layer 133 and the first upper adhesive layer 134 may contact each other at opposite ends of the first strip terminal in the width direction, the first strip terminal 230 of the secondary battery according to the second embodiment of the present disclosure may further include a first foaming portion extension 235, and therefore, the first lower adhesive layer 233 and the first upper adhesive layer 234 may be spaced apart from each other by the first foaming portion extension 235 at opposite ends of the first strip terminal in the width direction (e.g., X direction). For example, as Figure 3As shown in FIG. 2 , the first foaming portion extension 235 may be between the first lower adhesive layer 233 and the first upper adhesive layer 234 .

[0067] In one embodiment, the first foaming portion extension 235 may extend from the first foaming portion 232 to the opposite side in the width direction. In one embodiment, the opposite ends of the first foaming portion extension 235 in the width direction may coincide with the opposite ends of the first lower adhesive layer 233 and the first upper adhesive layer 234 in the width direction.

[0068] The first foaming portion extension 235 may be made of the same material as the first foaming portion 232. Therefore, there may be no clear boundary between the first foaming portion 232 and the first foaming portion extension 235, and the first foaming portion 232 and the first foaming portion extension 235 may be formed integrally with each other.

[0069] refer to Figure 4 , the first strip-shaped terminal 230 can be manufactured in the following manner.

[0070] First, the member L1 for forming the first lower adhesive layer 233 may be placed and prepared to be elongated in the width direction. Next, the material L2 for forming the first foaming portion 232 and the first foaming portion extension 235 may be completely placed on the member L1, and then the first conductor portion 231 may be placed on the material L2 at regular intervals along the width direction (e.g., X direction).

[0071] Subsequently, the material L2 for forming the first foamed portion 232 and the first foamed portion extension 235 may be placed thereon, and then the member L3 for forming the first upper adhesive layer 234 may be placed and prepared to be elongated in the width direction.

[0072] Finally, the spaces between the first conductor parts 231 may be cut at regular intervals.

[0073] In this way, each cutting section can form one first strip-shaped terminal 230 , and thus a plurality of first strip-shaped terminals 230 can be easily and quickly manufactured.

[0074] The first strip terminal 230 may be formed in the same configuration as the first strip terminal 130 of the secondary battery 100 according to the first embodiment of the present disclosure, except that the first strip terminal 230 may further include a first foaming portion extension 235 and may have a structural change accordingly. Therefore, repeated explanation of the rest will be omitted.

[0075] In addition, the second strip terminal of the secondary battery according to the second embodiment of the present disclosure may be formed to have the same structure as the first strip terminal 230. Therefore, repeated explanation will also be omitted.

[0076] Figure 5is a cross-sectional view of a first strip terminal 330 of a secondary battery according to a third embodiment of the present disclosure, showing Figure 2 The corresponding part in .

[0077] The secondary battery according to the third embodiment of the present disclosure may include an electrode assembly, a housing, a first strip-shaped terminal 330, and a second strip-shaped terminal. However, the electrode assembly and the housing of the secondary battery according to the third embodiment of the present disclosure may have the same configuration as the electrode assembly 110 and the housing 120 of the secondary battery 100 according to the first embodiment of the present disclosure. Therefore, repeated explanations will also be omitted.

[0078] By comparing reference Figure 2 and Figure 5 , except that the first strip terminal 330 of the secondary battery according to the third embodiment of the present disclosure may further include a first lower heat-resistant layer 335 and a first upper heat-resistant layer 336 .

[0079] The first lower heat-resistant layer 335 may be between the first foaming part 332 and the first lower adhesive layer 333. The first lower heat-resistant layer 335 may be made of a material having a higher melting point than the first lower adhesive layer 333. In one embodiment, if the melting point of the first lower adhesive layer 333 is about 120°C to 140°C, the melting point of the first lower heat-resistant layer 335 may be about 160°C to 165°C.

[0080] The first upper heat-resistant layer 336 may be between the first foaming part 332 and the first upper adhesive layer 334. The first upper heat-resistant layer 336 may be made of a material having a higher melting point than the first upper adhesive layer 334. In one embodiment, if the melting point of the first upper adhesive layer 334 is about 120°C to 140°C, the melting point of the first upper heat-resistant layer 336 may be about 160°C to 165°C.

[0081] If thermally bonded along the land portion, heat may be transferred from the first lower adhesive layer 333 and the first upper adhesive layer 334 to the first foaming portion 332 through the first lower heat-resistant layer 335 and the first upper heat-resistant layer 336, thereby more effectively preventing the foaming particles from foaming.

[0082] The first strip terminal 330 may be formed in the same configuration as the first strip terminal 130 of the secondary battery 100 according to the first embodiment of the present disclosure, except that the first strip terminal 330 may further include a lower heat-resistant layer 335 and a first upper heat-resistant layer 336 and may have a structural change accordingly. Therefore, repeated explanation of the rest will be omitted.

[0083] In addition, the second strip terminal of the secondary battery according to the third embodiment of the present disclosure may be formed to have the same structure as the first strip terminal 330. Therefore, repeated explanation will also be omitted.

[0084] Figure 6 is a cross-sectional view of a first strip terminal 430 of a secondary battery according to a fourth embodiment of the present disclosure, showing Figure 2 The corresponding part in .

[0085] The secondary battery according to the fourth embodiment of the present disclosure may include an electrode assembly, a housing, a first strip-shaped terminal 430, and a second strip-shaped terminal. However, the electrode assembly and the housing of the secondary battery according to the fourth embodiment of the present disclosure may have the same configuration as the electrode assembly 110 and the housing 120 of the secondary battery 100 according to the first embodiment of the present disclosure. Therefore, repeated explanations will also be omitted.

[0086] By comparing reference Figure 5 and Figure 6 , the difference is that, although the first foaming portion 332 of the first strip terminal 330 of the secondary battery according to the third embodiment of the present disclosure may surround the first conductor portion 331 and the first lower heat-resistant layer 335 and the first upper heat-resistant layer 336 may contact each other at opposite ends of the first strip terminal in the width direction, the first strip terminal 430 of the secondary battery according to the fourth embodiment of the present disclosure may further include a first foaming portion extension 437, and therefore, the first lower heat-resistant layer 435 and the first upper heat-resistant layer 436 may be spaced apart from each other by the first foaming portion extension 437 at opposite ends of the first strip terminal in the width direction (e.g., X direction). For example, as Figure 6 As shown in FIG. 4 , the first foaming portion extension 437 may be between the first lower heat-resistant layer 435 and the first upper heat-resistant layer 436 .

[0087] In one embodiment, the first foaming portion extension 437 may extend from the first foaming portion 432 to the opposite side in the width direction. In particular, the opposite ends of the first foaming portion extension 437 in the width direction may coincide with the opposite ends of the first lower heat-resistant layer 435 and the first upper heat-resistant layer 436 in the width direction and the opposite ends of the first lower adhesive layer 433 and the first upper adhesive layer 434 in the width direction.

[0088] The first foaming portion extension 437 may be made of the same material as the first foaming portion 432. Therefore, there may be no clear boundary between the first foaming portion 432 and the first foaming portion extension 437, and the first foaming portion 432 and the first foaming portion extension 437 may be formed integrally with each other.

[0089] The first strip-shaped terminal 430 may be manufactured in the following manner.

[0090] First, a member for forming the first lower adhesive layer 433 may be placed and prepared to be elongated in the width direction. Next, a material for forming the first lower heat-resistant layer 435 may be completely placed on the member for forming the first lower adhesive layer 433 .

[0091] Then, the material for forming the first foaming portion 432 and the first foaming portion extension 437 can be completely placed on the material for forming the first lower heat-resistant layer 435, and the first conductor portion 431 can be placed on the material for forming the first foaming portion 432 and the first foaming portion extension 437 at regular intervals along the width direction (for example, the X direction).

[0092] Subsequently, the material for forming the first foaming portion 432 and the first foaming portion extending portion 437 may be placed again, and then the member for forming the first upper heat-resistant layer 436 may be placed on the material for forming the first foaming portion 432 and the first foaming portion extending portion 437. Thereafter, the member for forming the first upper adhesive layer 434 may be prepared to be elongated in the width direction and placed on the member for forming the first upper heat-resistant layer 436.

[0093] Finally, the spaces between the first conductor parts 431 may be cut at regular intervals.

[0094] In this way, each cutting section can form one first strip-shaped terminal 430 , and thus a plurality of first strip-shaped terminals 430 can be easily and quickly manufactured.

[0095] The first strip terminal 430 may be formed in the same configuration as the first strip terminal 330 of the secondary battery according to the third embodiment of the present disclosure, except that the first strip terminal 430 may further include a first foaming portion extension 437 and may have a structural change accordingly. Therefore, repeated explanation of the rest will be omitted.

[0096] In addition, the second strip terminal of the secondary battery according to the fourth embodiment of the present disclosure may be formed to have the same structure as the first strip terminal 430. Therefore, repeated explanation will also be omitted.

[0097] By way of summary and review, if a secondary battery is exposed to high temperature, as the electrolyte evaporates, gas may be generated, so that the electrode assembly may be improperly deformed, and in severe cases, fire may occur. Accordingly, a technology that can release gas at an appropriate time is required.

[0098] As described above, in an embodiment of the present disclosure, the strip terminal may include a foaming portion containing foamed particles that foam under a predetermined temperature condition, and therefore, when the secondary battery is exposed to a high temperature, the foamed particles may foam, thereby generating a gap between the housing and the strip terminal. Therefore, by discharging gas through the gap, the electrode assembly and even the secondary battery may be prevented from being improperly deformed or ignited. In particular, in the strip terminal, the foaming portion may surround a conductor portion having relatively excellent thermal conductivity, so that heat may be more effectively transferred to the foaming portion, thereby ensuring that the foamed particles are more reliably foamed.

[0099] Embodiments of the present disclosure provide a secondary battery capable of efficiently exhausting gas.

[0100] Example embodiments have been disclosed herein, and although specific terms are employed, they are used and interpreted in a general and descriptive sense only and not for purposes of limitation. In some cases, as would be apparent to one of ordinary skill in the art at the time of filing this application, features, characteristics, and / or elements described in conjunction with a particular embodiment may be used alone or in combination with features, characteristics, and / or elements described in conjunction with other embodiments, unless specifically indicated otherwise. Accordingly, those skilled in the art will appreciate that various changes may be made in form and detail without departing from the spirit and scope of the invention as set forth in the claims.

Claims

1. A secondary battery comprising: Electrode assembly; A shell, accommodating the electrode assembly; as well as Strip terminal, comprising: A conductor portion connected to the electrode assembly and extending outward; a foaming portion surrounding the conductor portion and containing foamed particles foamed under a predetermined temperature condition; and An adhesive layer surrounds the foamed portion and is bonded to the housing. 2 . The secondary battery according to claim 1 , wherein the foamed portion at least partially surrounds the conductor portion. The secondary battery according to claim 1 , wherein the foamed portion completely surrounds the conductor portion.

4. The secondary battery according to claim 1, wherein: The housing comprises: a lower case having a concave portion for accommodating the electrode assembly; and an upper shell covering the lower shell, The lower shell and the upper shell are thermally bonded along the platform portion of the lower shell and the platform portion of the upper shell, The conductor portion extends outwardly between the lower housing and the upper housing, and The adhesive layer comprises: a lower adhesive layer between the foaming portion and the platform portion of the lower housing; and An upper adhesive layer is between the foaming portion and the platform portion of the upper shell. 5 . The secondary battery according to claim 4 , wherein heat required for foaming the foamed particles is greater than heat required for thermally combining the lower case and the upper case. 6 . The secondary battery according to claim 4 , wherein the lower adhesive layer and the upper adhesive layer each have a width greater than a width of the foamed portion. 7 . The secondary battery according to claim 6 , wherein the lower adhesive layer and the upper adhesive layer contact each other at opposite ends of the strip terminal in a width direction.

8. The secondary battery according to claim 6, wherein: The strip terminal further includes a foam portion extending portion extending from the foam portion to opposite ends of the strip terminal in a width direction, and The lower adhesive layer and the upper adhesive layer are spaced apart from each other by the foaming portion extension at the opposite ends of the strip terminal in the width direction. 9 . The secondary battery according to claim 8 , wherein opposite ends of the foamed portion extension in the width direction coincide with opposite ends of the lower adhesive layer and the upper adhesive layer in the width direction. 10 . The secondary battery according to claim 1 , wherein the strip terminal further comprises a heat-resistant layer between the foamed portion and the adhesive layer. 11 . The secondary battery according to claim 10 , wherein the heat-resistant layer is made of a material having a higher melting point than that of the adhesive layer.

12. The secondary battery according to claim 10, wherein: The housing comprises: a lower case having a concave portion for accommodating the electrode assembly; and an upper shell covering the lower shell, The lower shell and the upper shell are thermally bonded along the platform portion of the lower shell and the platform portion of the upper shell, The conductor portion extends outward between the lower shell and the upper shell, The adhesive layer comprises: a lower adhesive layer between the foaming portion and the platform portion of the lower housing; and an upper adhesive layer between the foaming portion and the platform portion of the upper shell, and The heat-resistant layer comprises: a lower heat-resistant layer between the foamed portion and the lower adhesive layer; and An upper heat-resistant layer is between the foamed portion and the upper adhesive layer. 13 . The secondary battery according to claim 12 , wherein heat required for foaming the foamed particles is greater than heat required for thermally combining the lower case and the upper case. 14 . The secondary battery according to claim 13 , wherein the lower and upper adhesive layers and the lower and upper heat-resistant layers each have a width greater than a width of the foamed portion. 15 . The secondary battery according to claim 14 , wherein the lower heat-resistant layer and the upper heat-resistant layer contact each other at opposite ends of the strip terminal in a width direction.

16. The secondary battery according to claim 14, wherein: The strip terminal further includes a foam portion extending portion extending from the foam portion to opposite ends of the strip terminal in a width direction, and The lower heat-resistant layer and the upper heat-resistant layer are spaced apart from each other by the foamed portion extension at the opposite ends of the strip terminal in the width direction. 17 . The secondary battery according to claim 16 , wherein opposite ends of the foamed portion extension in the width direction coincide with opposite ends of the lower adhesive layer and the upper adhesive layer in the width direction and opposite ends of the lower heat-resistant layer and the upper heat-resistant layer in the width direction. 18 . The secondary battery according to claim 1 , wherein the foamed particles include azodicarbonamide, 4,4′-oxybis(benzenesulfonylhydrazide), or N,N′-dinitrosopentamethylenetetramine.

19. A method for manufacturing a strip terminal, the method comprising: preparing and placing a member for forming a lower adhesive layer so as to be elongated in a width direction; placing a material for forming a foamed portion and a foamed portion extension on the member for forming a lower adhesive layer; placing conductor portions spaced at regular intervals in the width direction on the material for forming the foamed portion and the foamed portion extension; placing an additional material for forming the foamed portion and the foamed portion extension on the material for forming the foamed portion and the foamed portion extension and the conductor portion; placing a member for forming an upper adhesive layer on the additional material for forming the foamed portion and the foamed portion extension; as well as The member for forming the lower adhesive layer, the material for forming the foamed portion and the foamed portion extension, the additional material for forming the foamed portion and the foamed portion extension, and the member for forming the upper adhesive layer are cut at regular intervals along the width direction in the space between the conductor portions spaced at regular intervals along the width direction.

20. A method for manufacturing a strip terminal, the method comprising: preparing and placing a member for forming a lower adhesive layer so as to be elongated in a width direction; placing a material for forming a lower heat-resistant layer on the member for forming a lower adhesive layer; placing a material for forming a foamed portion and a foamed portion extension on the material for forming a lower heat-resistant layer; placing conductor portions spaced at regular intervals in the width direction on the material for forming the foamed portion and the foamed portion extension; placing an additional material for forming the foamed portion and the foamed portion extension on the material for forming the foamed portion and the foamed portion extension and the conductor portion; placing a material for forming an upper heat-resistant layer on the additional material for forming the foamed portion and the foamed portion extension; placing a member for forming an upper adhesive layer on the material for forming an upper heat-resistant layer; as well as The member for forming the lower adhesive layer, the material for forming the lower heat-resistant layer, the material for forming the foaming portion and the foaming portion extension, the additional material for forming the foaming portion and the foaming portion extension, the material for forming the upper heat-resistant layer, and the member for forming the upper adhesive layer are cut at regular intervals along the width direction in the space between the conductor portions spaced at regular intervals along the width direction.

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