Secondary battery

Abstract

One or more embodiments relate to a secondary battery capable of suppressing internal stress of a side portion of an electrode assembly and capable of securing an internal space of a case. The secondary battery includes: a case having a space defined therein; an electrode assembly in the case and including a positive electrode plate, a negative electrode plate, and a separator wound in a cylindrical shape, and an adhesive portion adhering and fixing a winding end of an outermost surface of the electrode assembly; and a cover assembly sealing the housing.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2024-0049803 filed on April 15, 2024, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0002] Embodiments relate to a secondary battery. Background Art

[0003] Typically, a secondary battery includes an electrode assembly, a housing, and a cap assembly. The electrode assembly may have a cylindrical shape. The housing may have a cylindrical shape and may house the electrode assembly and electrolyte. The cap assembly may be coupled to the upper opening of the housing to seal the housing. The cap assembly may allow current generated by the electrode assembly to flow to an external device.

[0004] The electrode assembly includes a positive electrode plate, a negative electrode plate, and a separator. The separator is located between the positive and negative electrode plates. The electrode assembly is formed by winding the positive, negative, and separator plates. The electrode assembly is formed into a cylindrical shape. The ends of the electrode assembly are secured with sealing tape. The wound ends of the electrode assembly do not unwind.

[0005] The information disclosed in this section is provided only for enhancement of understanding of the background of the present disclosure and therefore it may contain information that does not constitute prior art. Summary of the Invention

[0006] One or more embodiments relate to a secondary battery capable of suppressing internal stress of a side portion of an electrode assembly and ensuring an internal space of a case.

[0007] A secondary battery according to one or more embodiments includes: a shell defining a space therein; an electrode assembly in the shell and including a positive electrode plate, a negative electrode plate, and a separator wound into a cylindrical shape, and an adhesive portion adhering and fixing a winding end of an outermost surface of the electrode assembly; and a cap assembly sealing the shell.

[0008] The bonding portion may be along a boundary line of the rolled end.

[0009] The bonding portion may comprise a spaced apart pattern or a continuous pattern.

[0010] An end portion of the separator may be at an outermost portion of the electrode assembly, wherein the bonding portion is along the end portion of the separator.

[0011] The bonding portion may include a pattern at equal intervals.

[0012] The bonding part may include patterns having the same length.

[0013] The adhesive portion may be fixed to the outermost surface by fusion or bonding.

[0014] The adhesive portion may be fixed to the outermost surface by thermal fusion.

[0015] The adhesive part may include first adhesive parts at the top and bottom of the electrode assembly, respectively, and a second adhesive part between the first adhesive parts.

[0016] The second adhesive portion may extend along an extending direction of the rolled end, wherein the second adhesive portion is in the same direction as the first adhesive portion, or the second adhesive portion is in a direction perpendicular or substantially perpendicular to the first adhesive portion. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings incorporated into this specification illustrate embodiments and are used to further illustrate the technical concept of the present disclosure in conjunction with the detailed description of the following embodiments, and the present disclosure should not be construed as being limited to the contents shown in these drawings. In the drawings:

[0018] Figure 1 is a cross-sectional view illustrating a secondary battery according to one or more embodiments.

[0019] Figure 2a is a partially disassembled perspective view illustrating a secondary battery according to one or more embodiments.

[0020] Figure 2b is an exploded perspective view showing a state in which the electrode plate and the terminal tab are coupled.

[0021] Figures 3 to 6 is a perspective view of an electrode assembly of a secondary battery according to an embodiment. DETAILED DESCRIPTION

[0022] Hereinafter, some embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be restrictively interpreted as conventional or dictionary meanings, but should be interpreted as meanings and concepts consistent with the technical ideas of the present disclosure based on the principle that the inventor can be his / her own lexicographer to appropriately define terminology concepts to best describe his / her exemplary embodiments.

[0023] The embodiments described in this specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure and do not represent all the technical spirit, aspects and features of the present disclosure. Therefore, it should be understood that at the time of filing this application, various equivalents and modifications that can replace or modify the embodiments described herein may exist.

[0024] It should be understood that when an element or layer is referred to as being “on,” “connected to,” or “coupled to” another element or layer, it can be directly on, connected to, or coupled to the other element or layer, or one or more intervening elements or layers may be present. When an element or layer is referred to as being “directly on,” “directly connected to,” or “directly coupled to” another element or layer, there are no intervening elements or layers. For example, when a first element is described as being “coupled to” or “connected to” a second element, the first element can be directly coupled or connected to the second element, or the first element can be indirectly coupled or connected to the second element via one or more intervening elements.

[0025] In the accompanying drawings, for clarity of illustration, the sizes of various elements, layers, etc. may be magnified. The same reference numerals indicate the same elements. As used herein, the term "and / or" includes any and all combinations of one or more associated listed items. In addition, the use of "may" when describing the embodiments of the present disclosure relates to "one or more embodiments of the present disclosure." Expressions such as "at least one" and "any one" before a list of elements modify the entire list of elements without modifying the individual elements in the list. When phrases such as "at least one of A, B, and C," "at least one of A, B, or C," "at least one selected from the group of A, B, and C," or "at least one selected from A, B, and C" are used to specify a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term "use" may be considered synonymous with the term "utilize." As used herein, the terms "substantially," "about," and similar terms are used as terms of approximation rather than terms of degree, and are intended to take into account the inherent variations in measurements or calculations that one of ordinary skill in the art would appreciate.

[0026] It should be understood that although the terms "first," "second," "third," etc. may be used to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Thus, a first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments.

[0027] For ease of description, spatial relative terms such as "below," "under," "down," "above," "on," etc. may be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures. It should be understood that spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figure is flipped, an element described as "below" or "below" other elements or features can be oriented to be "above" or "on" other elements or features. Therefore, the term "below" can include both above and below. The device can be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relative descriptors used herein should be interpreted accordingly.

[0028] The terms used herein are for the purpose of describing the embodiments of the present disclosure and are not intended to limit the present disclosure. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. It should be further understood that the terms "comprise" and / or "comprising" when used in this specification specify the presence of the features, integers, steps, operations, elements and / or parts, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, parts and / or groups thereof.

[0029] In addition, any numerical range disclosed and / or listed herein is intended to include all subranges of the same numerical precision contained in the listed range. For example, the range of "1.0 to 10.0" is intended to include all subranges between the listed minimum value 1.0 and the listed maximum value 10.0 (and including the listed minimum value 1.0 and the listed maximum value 10.0), i.e., having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, for example, such as 2.4 to 7.6. Any maximum numerical value limit listed herein is intended to include all lower numerical limits contained therein, and any minimum numerical value limit listed in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification including the claims to clearly enumerate any subrange contained in the scope clearly enumerated herein. All such ranges are intended to be inherently described in this specification so that the modifications made in order to clearly enumerate any such subranges will meet the requirements.

[0030] Referring to two compared elements, features, etc. as "the same" may mean that they are "substantially the same." Thus, the phrase "substantially the same" can include situations with what is considered to be low variance in the art, for example, 5% or less. Furthermore, when a parameter is referred to as being consistent in a given area, this may mean that it is consistent with respect to the average value.

[0031] Throughout the specification, unless otherwise specified, each element may be in the singular or in the plural.

[0032] Arranging any element “on (or below)” or “over (or under)” another element may mean that the arbitrary element may be positioned in contact with the upper surface (or lower surface) of the element, and other elements may also be interposed between the element and any element positioned on (or under) the element.

[0033] Further, it will be understood that when a component is referred to as being “linked,” “coupled” or “connected” to another component, the elements can be directly “coupled,” “linked” or “connected” to each other or another component may be “interposed” between the components.

[0034] Throughout this specification, unless otherwise indicated, when "A and / or B" is stated, it means A, B, or A and B. In other words, "and / or" includes any or all combinations of the listed items. Unless otherwise indicated, when "C to D" is stated, it means C or more and D or less.

[0035] Hereinafter, a secondary battery according to one or more embodiments will be described with reference to the accompanying drawings.

[0036] Figure 1 is a cross-sectional view illustrating a secondary battery according to one or more embodiments. Figure 2a is a partially disassembled perspective view illustrating a secondary battery according to one or more embodiments. Figure 2b is an exploded perspective view showing a state in which the electrode plate and the terminal tab are coupled.

[0037] See also Figure 1 、 Figure 2a and Figure 2b , a secondary battery 1 according to one or more embodiments may include a cylindrical case 10, an electrode assembly 30, and a cap assembly 50 for sealing the case 10. One end of the case 10 in a longitudinal direction is open.

[0038] The housing 10 may include a bottom 12 and a side 14. The bottom 12 may be circular. The side 14 may extend upward from the bottom 12. The side 14 (e.g., the upper end of the side 14) is open. During the manufacturing process of the secondary battery, the electrode assembly and the electrolyte are accommodated in the housing 10 through the opening of the housing 10. The housing may include steel, alloy steel, nickel-plated steel, aluminum, aluminum alloy, or their equivalents.

[0039] The curling portion 16 and the crimping portion 18 are located on the side portion 14. The cover assembly 50 may be fixed by the curling portion 16 and the crimping portion 18. The side portion 14 may be concavely bent toward the inside of the shell 10, and the curling portion 16 may be formed. The curling portion 16 and the electrode assembly 30 may be spaced apart from each other. In one or more embodiments, the curling portion 16 and the electrode assembly 30 do not contact each other. When the cover assembly 50 is assembled, the cover assembly 50 is supported by the curling portion 16. After the cover assembly 50 is assembled, the end of the side portion 14 may be bent toward the inside of the shell 10, and the crimping portion 18 may be formed. The cover assembly 50 may be fixed by the crimping portion 18. The crimping portion 18 and the electrode assembly 30 may be spaced apart from each other. In one or more embodiments, the crimping portion 18 and the electrode assembly 30 do not contact each other.

[0040] The electrode assembly 30 may include a negative electrode plate 31 having a negative electrode active material (e.g., graphite, carbon, etc.) coated on a negative electrode current collector plate, a positive electrode plate 32 having a positive electrode active material (e.g., a transition metal oxide, such as LiCoO2, LiNiO2, LiMn2O4, etc.) coated on a positive electrode current collector plate, and a separator 33 positioned between the negative electrode plate 31 and the positive electrode plate 32 to reduce or prevent the possibility of a short circuit therebetween while allowing lithium ions to move therethrough.

[0041] The negative electrode plate 31 may be copper (Cu) or nickel (Ni) foil. The positive electrode plate 32 may be aluminum (Al) foil. The separator 33 may be polyethylene (PE) or polypropylene (PP).

[0042] The negative electrode plate 31 may include a coating portion 31a coated with a negative electrode active material and an uncoating portion 31b not coated with the negative electrode active material. The positive electrode plate 32 may include a coating portion 32a coated with a positive electrode active material and an uncoating portion 32b not coated with the positive electrode active material.

[0043] The negative electrode tab 34 protruding downward to a corresponding length (e.g., a predetermined length) can be welded to the uncoated portion 31b of the negative electrode plate 31. Moreover, the positive electrode tab 35 protruding upward to a corresponding length (e.g., a predetermined length) can be welded to the uncoated portion 32b of the positive electrode plate 32. The negative electrode tab 34 can be welded to the bottom 12 of the case 10. The positive electrode tab 35 can be welded to the cap assembly 50. The case 10 can be a negative electrode, and the cap assembly 50 can be a positive electrode. However, embodiments are not limited thereto. Tabs 34 and 35 may not be coupled to the uncoated portions 31b and 32b. The uncoated portions 31b and 32b may protrude upward or downward. The uncoated portions 31b and 32b may be electrically connected to the cap assembly 50 and the case 10 through separate current collecting plates.

[0044] The negative electrode plate 31, the positive electrode plate 32, and the separator 33 may be wound into a cylindrical shape to form the electrode assembly 30. The electrode assembly 30 may be housed in the case 10. In this case, the winding end of the outer surface (e.g., the outermost surface) of the electrode assembly 30 should not be unwound. The structure in which the winding end is not unwound is described below.

[0045] The cover assembly 50 may include a safety vent 51, an upper cover 52, and a lower cover 53. The upper cover 52 may be located on the safety vent 51. The lower cover 53 may be located below the safety vent 51. In one or more embodiments, the cover assembly 50 may further include an insulating member 54 and an insulating gasket 55. The insulating member 54 may be located between the safety vent 51 and the lower cover 53. Portions of the safety vent 51 other than its central portion do not contact the lower cover 53. The cover assembly 50 and the housing 10 may be insulated by the insulating gasket 55. The central portion of the safety vent 51 may contact the lower cover 53. The portion of the safety vent 51 supported by the insulating member 54 may be spaced apart from the lower cover 53. A notch may be formed in the safety vent 51. When the internal pressure of the housing 10 increases to greater than or equal to the corresponding pressure (e.g., a predetermined pressure), the notch may rupture and gas may be discharged.

[0046] Hereinafter, an electrode assembly of a secondary battery according to one or more embodiments will be described in detail.

[0047] Figure 3 is a perspective view of an electrode assembly of a secondary battery according to one or more embodiments.

[0048] refer to Figure 3 , the electrode assembly 30 may be wound. For example, the end portion 33a (e.g., end portion) of the separator 33 may be located at the outermost portion of the electrode assembly 30. In one or more embodiments, the separator 33 may form the outer surface (e.g., outermost surface) of the electrode assembly 30, and the winding end of the outer surface (e.g., outermost surface) of the electrode assembly 30 may be the end portion 33a of the separator 33.

[0049] The end portion 33a may be the portion where winding is completed. When the end portion 33a is not fixed, the electrode assembly 30 may be unwound. Therefore, the end portion 33a may be adhered. For example, the end portion 33a may be adhered along the boundary line of the end portion 33a (the height direction of the electrode assembly). Therefore, the possibility of unwinding the end portion 33a can be reduced or prevented.

[0050] For example, the end portion 33a can be thermally fused. For example, the end portion 33a can be fused by contacting a strip heater. In one or more embodiments, the end portion 33a can be bonded by an adhesive. For example, the end portion 33a can be bonded by a plurality of bonding portions 36. The plurality of bonding portions 36 can be spaced apart from each other. The plurality of bonding portions 36 can be formed in a pattern. In one or more embodiments, the possibility of the end portion 33a unwinding can be reduced or prevented. Moreover, even if a partial area of ​​the end portion 33a is deformed, it can be properly bonded. In addition, even if any bonding portion is defective, the end portion 33a can be bonded by other bonding portions. In one or more embodiments, the wound shape of the electrode assembly 30 can be maintained.

[0051] The end portion 33a can be fixed to the outermost portion of the electrode assembly 30 by the adhesive portion 36. A separate sealing tape (or termination tape) is not required for the electrode assembly 30. Stress caused by a material difference (e.g., a difference in elongation) between the separator 33 and the sealing tape (e.g., internal stress on the side of the electrode assembly 30) can be avoided or reduced.

[0052] The sealing tape may be continuously bonded along the winding end of the electrode assembly. However, the winding end of the electrode assembly 30 according to one or more embodiments (e.g., the end portion 33a or the end portion of the separator 33) is fixed by an adhesive portion 36 (e.g., an adhesive portion 36 formed by heat fusion). In one or more embodiments, the winding end of the electrode assembly 30 (e.g., the end portion 33a or the end portion of the separator 33) is bonded by a plurality of adhesive portions 36. In one or more embodiments, even if the electrode assembly 30 expands, the internal stress caused by the sealing tape (e.g., the internal stress of the side portion of the electrode assembly 30) can be reduced.

[0053] Hereinafter, secondary batteries according to one or more other embodiments will be described.

[0054] Figure 4 is a perspective view of an electrode assembly of a secondary battery according to one or more other embodiments.

[0055] refer to Figure 4 , the end portion 33 a of the separator 33 may be located at the outermost portion of the electrode assembly 130 .

[0056] The end portion 33a may be adhered. The end portion 33a may be selectively adhered. For example, the end portion 33a may be adhered only to an area where unwinding may be relatively easy. For example, the end portion 33a may be heat-fused. For example, the end portion 33a may be fused by contact with a strip heater. In one or more embodiments, the end portion 33a may be bonded using an adhesive.

[0057] Adhesive portion 136 may be formed. Adhesive portion 136 may include a first adhesive portion 136a and a second adhesive portion 136b. First adhesive portion 136a is located on the upper and lower ends of electrode assembly 130. Second adhesive portion 136b is located between the upper and lower ends of electrode assembly 130.

[0058] The end portion 33a may be relatively easily unwound from the upper and lower ends of the electrode assembly 130. In one or more embodiments, the first adhesive portion 136a is located at the upper and lower ends of the electrode assembly 130.

[0059] The second adhesive portion 136b may be located in the middle portion of the electrode assembly 130. The second adhesive portion 136b may be formed in a plurality of patterns spaced apart from each other. The second adhesive portion 136b may be spaced apart from the first adhesive portion 136a. The second adhesive portion 136b may adhere only to a small (or relatively small) or minimum area so that the end portion 33a does not unwind.

[0060] Although the adhesive portion 136 is formed to have a relatively small or minimal area, the possibility of the end portion 33 a being released can be reduced or prevented.

[0061] Hereinafter, secondary batteries according to one or more other embodiments will be described.

[0062] Figure 5 is a perspective view of an electrode assembly of a secondary battery according to one or more other embodiments.

[0063] The electrode assembly 230 may include an adhesive portion 236. The adhesive portion 236 may adhere to the end portion 33a of the separator located on the outermost surface of the electrode assembly 230. For example, the end portion 33a may be thermally fused. For example, the end portion 33a may be fused by contact with a strip heater. In one or more embodiments, the end portion 33a may be bonded by an adhesive.

[0064] The adhesive portion 236 may include a first adhesive portion 236a and a second adhesive portion 236b. The first adhesive portion 236a may be located on the upper and lower ends of the electrode assembly 230. The second adhesive portion 236b may be located between the upper and lower ends of the electrode assembly 230. The second adhesive portion 236b may include a plurality of adhesive portions spaced apart from each other.

[0065] The end portion 33a may be relatively easily unwound from the upper and lower ends of the electrode assembly 230. In one or more embodiments, the first adhesive portion 236a is located at the upper and lower ends of the electrode assembly 230.

[0066] The second adhesive portion 236b may be located in the middle portion of the electrode assembly 230. The second adhesive portion 236b may be formed in a plurality of patterns spaced apart from each other. The second adhesive portion 236b may extend in a direction perpendicular or substantially perpendicular to the extension direction of the end portion 33a. For example, the extension direction of the second adhesive portion 236b may be perpendicular to the extension direction of the first adhesive portion 236a. The end portion 33a may be adhered relatively widely in the perpendicular direction of the end portion 33a by the second adhesive portion 236b. This may reduce or prevent the possibility of the end portion 33a being released.

[0067] Hereinafter, secondary batteries according to one or more other embodiments will be described.

[0068] Figure 6 is a perspective view of an electrode assembly of a secondary battery according to one or more other embodiments.

[0069] The electrode assembly 330 may include an adhesive portion 336. The adhesive portion 336 may adhere to the end portion 33a of the separator located on the outermost surface of the electrode assembly 330. For example, the end portion 33a may be thermally fused. For example, the end portion 33a may be fused by contact with a strip heater. In one or more embodiments, the end portion 33a may be bonded by an adhesive.

[0070] The adhesive portion 336 may be formed continuously along the end portion 33a. The adhesive portion 336 may be formed along the extending direction of the end portion 33a. Furthermore, adjacent adhesive portions 336 may overlap each other. The adhesive portions 336 may include overlapping regions 336a. The adhesive portion 336 may be formed over the entire end portion by the overlapping regions 336a. This can reduce or prevent the possibility of the end portion 33a unwinding.

[0071] The secondary battery according to one or more embodiments includes an adhesive portion. The adhesive portion is formed by a fusion or bonding process. The adhesive portion is formed in a variety of patterns. In one or more embodiments, the possibility of unwinding the winding end of the electrode assembly can be reduced or prevented. The winding end can be fixed by the adhesive portion. The secondary battery according to one or more embodiments can reduce or prevent the internal stress generated by the sealing tape (for example, the internal stress of the side of the electrode assembly).

[0072] The above are only some embodiments for implementing the secondary battery according to the present disclosure. The present disclosure is not limited to the above, and the technical spirit of the present disclosure is within the following extent: any ordinary technician in the field to which the present disclosure belongs can make various modifications without departing from the main purpose of the present disclosure as claimed in the claims, including its functional equivalents.

Claims

1. A secondary battery comprising: a housing defining a space therein; an electrode assembly in the case and including a positive electrode plate, a negative electrode plate, and a separator wound into a cylindrical shape and an adhesive portion adhering and fixing a winding end of an outermost surface of the electrode assembly; as well as A cover assembly seals the housing. 2 . The secondary battery according to claim 1 , wherein the adhesive portion is along a boundary line of the winding end. 3 . The secondary battery according to claim 1 , wherein the adhesive part comprises a spaced apart pattern or a continuous pattern.

4. The secondary battery according to claim 1, wherein an end portion of the separator is at an outermost portion of the electrode assembly, and The bonding portion is along the end portion of the diaphragm. The secondary battery according to claim 1 , wherein the adhesive part comprises a pattern at equal intervals. The secondary battery according to claim 1 , wherein the adhesive part comprises patterns having the same length. 7 . The secondary battery according to claim 1 , wherein the adhesive portion is fixed to the outermost surface by fusion or bonding. 8 . The secondary battery according to claim 1 , wherein the adhesive portion is fixed to the outermost surface by thermal fusion. 9 . The secondary battery according to claim 1 , wherein the adhesive part comprises first adhesive parts at the top and bottom of the electrode assembly, respectively, and a second adhesive part between the first adhesive parts.

10. The secondary battery according to claim 9, wherein the second adhesive portion extends along an extending direction of the winding end, and The second adhesive portion is in the same direction as the first adhesive portion, or the second adhesive portion is in a direction perpendicular to the first adhesive portion.

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