Secondary battery

Abstract

A secondary battery includes: an electrode assembly including a first electrode, a separator, and a second electrode; a case accommodating the electrode assembly; a cap plate coupled to the opening of the housing; and a safety exhaust member at a side surface of one of the housing and the cover plate, the safety exhaust member including a plurality of exhaust plates, and each of the plurality of exhaust plates having a different bursting pressure.

Description

TECHNICAL FIELD

[0001] Aspects of embodiments of the present disclosure relate to a secondary battery. BACKGROUND

[0002] Unlike primary batteries that are not designed to be (re)charged, secondary (or rechargeable) batteries are batteries designed to be discharged and recharged. Low-capacity secondary batteries are used for portable small electronic devices such as smartphones, feature phones, notebook computers, digital cameras, and camcorders, and high-capacity secondary batteries are widely used as power sources that drive electric motors in hybrid and electric vehicles and store electric power (e.g., home and / or utility-scale power storage). A secondary battery generally includes an electrode assembly including a positive electrode and a negative electrode, a case that houses the electrode assembly, and an electrode terminal connected to the electrode assembly.

[0003] The above information disclosed in this Background section is only for enhancing the understanding of the background of the present disclosure, therefore, it can contain information that does not constitute the related (or prior) art. SUMMARY

[0004] A secondary battery according to an embodiment of the present disclosure includes an electrode assembly including a first electrode, a separator, and a second electrode; a case housing the electrode assembly; a cover coupled to an opening of the case; and a safety vent at a side of one of the case and the cover. The safety vent includes a plurality of vent plates, and each of the plurality of vent plates has a different rupture pressure.

[0005] According to an embodiment of the present disclosure, respective thicknesses of the plurality of vent plates can be different from each other.

[0006] According to an embodiment of the present disclosure, respective areas of the plurality of vent plates can be different from each other.

[0007] According to an embodiment of the present disclosure, the safety vent can include a first notch between adjacent vent plates among the plurality of vent plates.

[0008] According to an embodiment of the present disclosure, a connection portion between each of the plurality of vent plates and the first notch can have a different minimum thickness.

[0009] According to an embodiment of the present disclosure, the safety vent can include a second notch between each of the plurality of vent plates and the case.

[0010] According to an embodiment of the present disclosure, a connection portion between each of the plurality of vent plates and the second notch can have a different minimum thickness.

[0011] According to an embodiment of the present disclosure, the plurality of vent plates can include a first vent plate, a second vent plate, a third vent plate, and a fourth vent plate.

[0012] According to embodiments of the disclosure, the safety vent can be radially divided from any point of the safety vent to define a first vent plate, a second vent plate, a third vent plate, and a fourth vent plate.

[0013] According to embodiments of the disclosure, a thickness of the first vent plate can be greater than a thickness of the second vent plate, the thickness of the second vent plate can be greater than a thickness of the third vent plate, and the thickness of the third vent plate can be greater than a thickness of the fourth vent plate.

[0014] According to embodiments of the disclosure, the safety vent can include a first sub-notch between the first vent plate and the second vent plate, a second sub-notch between the second vent plate and the third vent plate, a third sub-notch between the third vent plate and the fourth vent plate, and a fourth sub-notch between the fourth vent plate and the first vent plate.

[0015] According to embodiments of the disclosure, a first minimum thickness of a connection portion between the first vent plate and the first sub-notch, a second minimum thickness of a connection portion between the second vent plate and the second sub-notch, a third minimum thickness of a connection portion between the third vent plate and the third sub-notch, and a fourth minimum thickness of a connection portion between the fourth vent plate and the fourth sub-notch can sequentially decrease or increase.

[0016] According to embodiments of the disclosure, the safety vent can include a fifth sub-notch between the first vent plate and one of the housing and the cover plate, a sixth sub-notch between the second vent plate and one of the housing and the cover plate, a seventh sub-notch between the third vent plate and one of the housing and the cover plate, and an eighth sub-notch between the fourth vent plate and one of the housing and the cover plate.

[0017] According to embodiments of the disclosure, a first minimum thickness of a connection portion between the first vent plate and the fifth sub-notch, a second minimum thickness of a connection portion between the second vent plate and the sixth sub-notch, a third minimum thickness of a connection portion between the third vent plate and the seventh sub-notch, and a fourth minimum thickness of a connection portion between the fourth vent plate and the eighth sub-notch can sequentially decrease or increase.

[0018] According to embodiments of the disclosure, the first sub-notch, the second sub-notch, the third sub-notch, and the fourth sub-notch can have the same thickness.

[0019] According to embodiments of the disclosure, the first sub-notch, the second sub-notch, the third sub-notch, and the fourth sub-notch can have different thicknesses.

[0020] According to embodiments of the disclosure, respective first surfaces of the first vent plate, the second vent plate, the third vent plate, and the fourth vent plate can be coplanar with each other.

[0021] According to an embodiment of the disclosure, the first sub-recess, the second sub-recess, the third sub-recess, and the fourth sub-recess can have the same depth with respect to the first surface of the first exhaust plate.

[0022] According to an embodiment of the disclosure, the respective second surfaces of the plurality of exhaust plates can not be coplanar with each other, the second surface being opposite to the first surface.

[0023] According to an embodiment of the disclosure, the safety exhaust member can include a plurality of exhaust plates arranged side by side in one direction. BRIEF DESCRIPTION OF DRAWINGS

[0024] The accompanying drawings, attached to this specification, illustrate embodiments of the present disclosure and, together with the description below, further describe the aspects and features of the present disclosure. Accordingly, the present disclosure should not be construed as being limited to the drawings.

[0025] Figure 1 is a perspective view illustrating an example of a secondary battery according to an embodiment of the present disclosure.

[0026] Figure 2 is a partially exploded perspective view illustrating an example of a secondary battery according to an embodiment of the present disclosure.

[0027] Figure 3 is Figure 1 is an enlarged perspective view of part A in

[0028] Figure 4 is a cross-sectional view taken along line B in Figure 3

[0029] Figure 5 is a perspective view illustrating another surface of a safety exhaust member opposite to one surface of the safety exhaust member according to an embodiment of the present disclosure.

[0030] Figure 6 is an enlarged perspective view of part C in Figure 5

[0031] Figure 7 is a plan view illustrating a safety exhaust member according to an embodiment of the present disclosure.

[0032] Figure 8 is a plan view illustrating a safety exhaust member according to an embodiment of the present disclosure.

[0033] Figure 9 is a plan view illustrating a safety exhaust member according to an embodiment of the present disclosure.

[0034] Figure 10 is a plan view illustrating a safety exhaust member according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] ​​Some embodiments of the present disclosure will be described in detail below with reference to the attached drawings. The terms or words used in the present specification and claims should not be interpreted as being limited to commonly used meanings or meanings in dictionaries and should be interpreted as having meanings and concepts consistent with the technical idea of the present disclosure based on the principle that the inventor can appropriately define the terms to best explain his / her own invention.

[0036] The embodiments described in the present specification and the configurations shown in the drawings are only some of the embodiments of the present disclosure, and do not represent all technical ideas, aspects and features of the present disclosure. Therefore, it should be understood that, at the time of filing the present application, there can be various equivalents and modifications that can replace or modify the embodiments described herein.

[0037] It will be understood that when an element or layer is referred to as being "on" another element or layer, "connected to" or "coupled to" another element or layer, it can be directly on the other element or layer, connected or coupled to the other element or layer, or one or more intervening elements or layers can also be present. When an element or layer is referred to as being "directly on" another element or layer, "directly connected to" or "directly coupled to" another element or layer, there are no intervening elements or layers present. For example, when a first element is described as "coupled" 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.

[0038] In the drawings, the size of various elements, layers, etc. can be exaggerated for clarity of illustration. The same reference numerals indicate the same elements. As used herein, the term "and / or" includes any and all combinations of one or more of the associated listed items. In addition, the use of "may" in describing the embodiments of the present disclosure relates to "one or more embodiments of the present disclosure". Expressions such as "at least one of" and "any one of" preceding / after a list of elements modify the entire list of elements and do not modify the individual elements of the list. When a phrase 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 consisting of A, B, and C", or "at least one selected from A, B, and C" is used to designate a list of elements A, B, and C, the phrase can 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" can be considered synonymous with the term "utilize". As used herein, the terms "substantially", "approximately", and similar terms are used as terms of approximation and not as terms of degree, and are intended to account for the inherent variations in measurements or calculations that would be recognized by those of ordinary skill in the art.

[0039] It will be understood that, although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.

[0040] For the purposes of this description, spatially relative terms such as "beneath", "below", "lower", "above", "upper" and the like can be used to describe one element's or feature's relationship to another element or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the figures. For example, if a device in the figures is inverted, elements described as "below" or "beneath" other elements or features would then be oriented "above" the other elements or features. Thus, the term "below" can encompass both an orientation of above and below. The device can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

[0041] The terminology used herein is for the purpose of describing embodiments of the disclosure and is not intended to be limiting of the disclosure. As used herein, singular forms are intended to include the plural forms unless the context clearly indicates otherwise. It will be further understood that the terms "includes" and / or "including," when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or groups thereof.

[0042] Furthermore, any numerical ranges herein are intended to include all sub-ranges of the same whole number precision used in the same range. For example, a range of 1.0 to 10.0 should be read to include the sub-ranges of 1.0 to 2.4, 2.4 to 4.0, 4.0 to 5.6, 5.6 to 8.0, 8.0 to 10.0, and 2.4 to 9.6, etc. Any maximum numerical limitation should be read as a minimum numerical limitation, and any minimum numerical limitation should be read as a maximum numerical limitation. All the numerical limitations recited herein should be understood to be open-ended ranges absent a contraindication in the specification. The recitation of numerical ranges by endpoints is intended to include all numbers subsumed within the range (e.g., 1 to 10 includes, e.g., 1, 1.5, 2, 2.75, 3, 4, 5, 6, 7, 8, 9, and 10).

[0043] Referring to two compared elements, features, etc., as "identical" can mean that they are "substantially identical". Thus, the phrase "substantially identical" can include having a deviation that is considered low in the art, for example, 5% or less. Also, when a certain parameter is referred to as uniform in a given region, it can mean that it is uniform in terms of an average value.

[0044] Throughout the specification, unless otherwise stated, each element can be singular or plural.

[0045] Arranging an arbitrary element "above (or below)" or "on (or under)" another element can mean that the arbitrary element can be disposed in contact with the upper surface (or lower surface) of the element, and other elements can also be interposed between the element and the arbitrary element disposed on (or under) the element.

[0046] Also, it will be understood that when a component is referred to as being "linked", "coupled", or "connected" to another component, then the element can be "coupled", "linked", or "connected" directly to one another, or another component can be "interposed" between the components.

[0047] Throughout the specification, unless otherwise stated, when stating "A and / or B", this 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 stating "C to D", it means greater than or equal to C and less than or equal to D.

[0048] Figure 1 is a perspective view illustrating an example of a secondary battery according to an embodiment of the disclosure, and Figure 2 is a perspective view illustrating Figure 1 a partially exploded perspective view of a secondary battery in

[0049] Referring to Figure 1 and Figure 2 , the secondary battery 10 can include an electrode assembly 120, a case 160 accommodating the electrode assembly 120, and a cap assembly 140. The electrode assembly 120 can include a first electrode plate (e.g., a first electrode 125), a separator 126, and a second electrode plate (e.g., a second electrode 127) wound or stacked therein.

[0050] The case 160 can form the overall appearance of the secondary battery 10, and can be made of an electrically conductive metal such as aluminum, an aluminum alloy, or nickel-plated steel. The case 160 can include long side wall portions 163 opposite each other, short side wall portions 164 opposite each other, and an opening 162 formed at one side of the case 160. The long side wall portions 163 can include a first long side wall portion and a second long side wall portion. The first long side wall portion and the second long side wall portion can be spaced apart from each other while facing each other. The short side wall portions 164 can include a first short side wall portion and a second short side wall portion. The first short side wall portion and the second short side wall portion can be spaced apart from each other while facing each other. In the illustrated example, the area of each of the first short side wall portion and the second short side wall portion can be smaller than the area of each of the first long side wall portion and the second long side wall portion.

[0051] The electrode assembly 120 can be accommodated within the case 160. The electrode assembly 120 can be formed by winding or stacking a stack of a first electrode plate, a separator, and a second electrode plate formed as a thin sheet or film. When the electrode assembly is a wound stack, a winding axis can be parallel to the longitudinal direction of the case 160. In other embodiments, the electrode assembly can be a stacked type rather than a wound type, and the shape of the electrode assembly is not limited in the present disclosure. Furthermore, the electrode assembly can be a Z-stack electrode assembly in which positive and negative electrode plates in the Z-stack electrode assembly are inserted to both sides of a separator and then bent into a Z-stack. Furthermore, one or more electrode assemblies can be stacked such that the long sides of the electrode assemblies are adjacent to each other and accommodated in the case 160, and the number of electrode assemblies in the case 160 is not limited in the present disclosure. The first electrode plate of the electrode assembly can serve as a negative electrode, and the second electrode plate can serve as a positive electrode. Of course, the reverse is also possible.

[0052] The first electrode plate can be formed by applying a first electrode active material such as graphite or carbon to a first electrode substrate formed of a metal foil such as copper, a copper alloy, nickel, or a nickel alloy. The first electrode plate can include a first electrode tab (or a first uncoated portion) as a region to which the first electrode active material is not applied. The first electrode tab can serve as a path for current flow between the first electrode plate and the cap assembly 140. In some embodiments, the first electrode tab can be formed by pre-cutting the first electrode plate during a manufacturing process of the first electrode plate such that the first electrode tab protrudes toward one side and extends farther than the separator that does not require additional cutting.

[0053] The second electrode plate can be formed by coating a second electrode active material, such as a transition metal oxide, onto a second electrode substrate formed of a metal foil such as aluminum or an aluminum alloy. The second electrode plate may include second electrode tabs (or second uncoated portions) as areas where the second electrode active material is not coated. The second electrode tabs can serve as paths for current flow between the second electrode plate and the cover assembly 140. In some embodiments, the second electrode tabs can be formed by pre-cutting the second electrode plate during its manufacturing process such that the second electrode tabs bulge to one side and extend further than a diaphragm that does not require additional cutting.

[0054] The cover assembly 140 can be coupled to an opening 162 formed on one side of the housing 160. In one embodiment, the cover assembly 140 may include a cover plate 141, a terminal plate 143, and a sealing member 142 insulating the cover plate 141 from the terminal plate 143. The terminal plate 143 can be coupled to a current collector for electrical connection to the electrode assembly. The cover assembly 140 can be positioned to cover one side of the housing 160. After the electrode assembly is housed in the housing 160, the cover assembly 140 can be joined to the housing 160 by methods such as welding to seal the interior of the housing 160.

[0055] In some embodiments, an electrolyte injection port 150 may be formed at the cover plate 141 of the cover assembly 140. Electrolyte can be injected into the housing 160 through the electrolyte injection port 150. For example, as... Figure 1 As shown, an electrolyte injection port 150 can be formed at the cover plate 141. After the electrolyte injection is completed, the electrolyte injection port 150 can be sealed by using a sealing device such as a plug.

[0056] In one embodiment, the safety vent 110 may be located on a side (e.g., a surface) of the cover assembly 140 or housing 160. For example, as Figure 1 As shown, the safety vent 110 may be located on a surface (i.e., a side surface) of the housing 160, rather than on the cover assembly 140. However, the mounting location of the safety vent 110 can vary; for example, the safety vent 110 may be located on the side surface of the cover assembly 140 (e.g., the cover plate 141). The safety vent 110 may be configured to prevent the secondary battery 10 from exploding or to prevent a chain reaction of exothermic reactions from other secondary batteries arranged adjacent to the secondary battery 110.

[0057] In an embodiment, the safety vent 110 can be configured to be ruptured in response to the internal pressure of the secondary battery 10 exceeding a predetermined pressure (e.g., a predetermined rupture pressure). Here, the rupture pressure can be adjusted differently according to the material of the secondary battery, the use of the secondary battery, etc. Further, in an embodiment, the safety vent 110 can include a plurality of vent plates. Accordingly, the safety vent 110 can have a plurality of rupture pressures. That is, each of the plurality of vent plates can have a different rupture pressure. This will be described in more detail later.

[0058] In an embodiment, the safety vent 110 can include a resin material. The resin material is a polymeric substance having various forms and properties. The resin material can have heat resistance such that it does not rupture at an internal temperature of approximately 200℃ of the secondary battery 10. Also, the resin material can be easily molded into a desired shape, and the cost of the resin material can be lower than that of the metal material, thereby reducing the manufacturing cost of the safety vent 110. The resin material can include a high heat-resistant material. Also, the high heat-resistant resin material can include one or more selected from polyimide (PI), polytetrafluoroethylene (PTFE), polypropylene (PP), polyphenylene sulfide (PPS), or a mixture thereof. However, the safety vent 110 can be alternatively formed of a metal material instead of the resin material.

[0059] Figure 3 is an enlarged perspective view of part A of Figure 1 , and Figure 4 is a cross-sectional view taken along line B in Figure 3 . Figure 5 is a perspective view illustrating another surface of a safety vent opposite to an outer surface of the safety vent according to an embodiment of the disclosure. Figure 6 is an enlarged perspective view of part C of Figure 5 .

[0060] Referring to Figure 1 and Figures 3 to 6 , the safety vent 110 can be disposed at one surface of the case 160, for example, part A of Figure 1 . The safety vent 110 can include a plurality of vent plates, each of which can have a different rupture pressure. For example, each vent plate of the safety vent 110 can be configured to be ruptured in response to a case in which the internal pressure exceeds a rupture pressure, which is a threshold pressure determined by the thickness of the vent plate or the notch, the area of the vent plate, the minimum thickness of the connection portion between the notch and the vent plate, etc.

[0061] For example, the plurality of vent plates can include a first vent plate 111, a second vent plate 112, a third vent plate 113, and a fourth vent plate 114. Each of the plurality of vent plates can have a different rupture pressure. For example, referring toFigures 3 to 5 Multiple exhaust plates can include four exhaust plates. In another example, multiple exhaust plates can include two, three, five or more exhaust plates.

[0062] In one embodiment, the thicknesses (e.g., along the Z-axis) of the plurality of exhaust plates (e.g., first exhaust plate 111, second exhaust plate 112, third exhaust plate 113, and fourth exhaust plate 114) can differ from each other. For example, the thickness t1 of the first exhaust plate 111 can be greater than the thickness of the second exhaust plate 112, the thickness of the second exhaust plate 112 can be greater than the thickness of the third exhaust plate 113, and the thickness of the third exhaust plate 113 can be greater than the thickness t2 of the fourth exhaust plate 114. For example, the thicknesses of the individual exhaust plates can decrease or increase with a difference of 0.2T (e.g., T = 1.0 mm). Therefore, by using a plurality of exhaust plates with different thicknesses, the bursting pressure can be adjusted for each of the plurality of exhaust plates.

[0063] In one embodiment, the first surfaces of the first vent plate 111, the second vent plate 112, the third vent plate 113, and the fourth vent plate 114 may be located in the same plane (e.g., coplanar or horizontal). For example, the first surface of each of the plurality of vent plates corresponding to the first surface of the safety vent 110 (e.g., a portion of the first surface) is the surface exposed outward from the housing 160 (e.g., a portion of the outer surface of the safety vent 110 facing the exterior of the housing 160), and the first surfaces of the plurality of vent plates are respectively arranged in the same plane. Accordingly, it may not be possible to reveal, by the appearance of the secondary battery, whether the plurality of vent plates forming the safety vent 110 have different thicknesses.

[0064] like Figure 5 As shown, the second surface of the safety vent 110 (i.e., the inner surface of the safety vent 110 facing the interior of the housing 160) can be the surface opposite to the first surface of the safety vent 110 exposed outward from the housing 160. In one embodiment, the second surfaces of the plurality of vent plates corresponding to the second surface of the safety vent 110 may include the second surface 136 of the first vent plate 111, the second surface 135 of the second vent plate 112, the second surface 137 of the third vent plate 113, and the second surface 138 of the fourth vent plate 114. In cases where each of the plurality of vent plates has a different thickness, the second surfaces 135, 136, 137, and 138 of the plurality of vent plates may not lie in the same plane as each other, while the first surfaces of the plurality of vent plates lie in the same plane as each other.

[0065] In one embodiment, reference Figure 5 and Figure 6The first notch can be formed between adjacent exhaust plates in a plurality of exhaust plates. For example, the first notch can be formed between adjacent exhaust plates in a plurality of exhaust plates, and the thickness of the connection portion between each first notch and the exhaust plate, such as the minimum thickness, can determine the bursting pressure of each exhaust plate.

[0066] In detail, such as Figures 3 to 5 As shown, the first recess may include a first sub-recess 118 formed between the first exhaust plate 111 and the second exhaust plate 112, a second sub-recess 115 formed between the second exhaust plate 112 and the third exhaust plate 113, a third sub-recess 116 formed between the third exhaust plate 113 and the fourth exhaust plate 114, and a fourth sub-recess 117 formed between the fourth exhaust plate 114 and the first exhaust plate 111.

[0067] Each of the first recesses (e.g., first sub-recess 118, second sub-recess 115, third sub-recess 116, and fourth sub-recess 117) may have a first surface facing the same direction as the first surface (the surface exposed outward from the housing) of each of the plurality of exhaust plates, and a second surface opposite to the first surface. For example, refer to Figure 3 Each sub-recess's first surface may face the exterior of the housing 160 and may be at a predetermined depth relative to the first surface of the adjacent exhaust plate. For example, refer to... Figure 5 The second surface of each sub-recess can face the interior of the housing 160 and can be opposite to the corresponding first surface. For example, refer to Figure 3 Each sub-notch can extend continuously along the entire length of the corresponding one in the exhaust plate.

[0068] In one embodiment, such as Figure 5 As shown, the second surfaces of the first notch (i.e., the second surface 131 of the first sub-notch 118, the second surface 134 of the second sub-notch 115, the second surface 133 of the third sub-notch 116, and the second surface 132 of the fourth sub-notch 117) can be located in the same plane as each other. Furthermore, the second surfaces 131 of the first sub-notch 118, 134 of the second sub-notch 115, 133 of the third sub-notch 116, and 132 of the fourth sub-notch 117 can have the same width (for example, the width of the second surface 134 of the second sub-notch 115 in the Y-axis direction can be equal to the width of the second surface 133 of the third sub-notch 116 in the X-axis direction).

[0069] In an embodiment, the first sub-notch 118 and the third sub-notch 116 can be located on the same line (e.g., can be collinear along the Y-axis direction), and the second sub-notch 115 and the fourth sub-notch 117 can be located on the same line (e.g., can be collinear along the X-axis direction). In an embodiment, the first sub-notch 118 and the third sub-notch 116 can perpendicularly intersect the second sub-notch 115 and the fourth sub-notch 117. For example, as shown in FIG. 1A, the intersection points of the first sub-notch 118 and the third sub-notch 116 with the second sub-notch 115 and the fourth sub-notch 117 can be formed at the center of the safety vent 110. Figures 3 to 5

[0070] The distance between the first surface and the second surface of each first notch can correspond to the thickness of the first notch. For example, each of the first sub-notch 118, the second sub-notch 115, the third sub-notch 116, and the fourth sub-notch 117 can have the same thickness. In another example, each of the first sub-notch 118, the second sub-notch 115, the third sub-notch 116, and the fourth sub-notch 117 can have different thicknesses. For example, the thickness of each of the first notches (e.g., the first sub-notch 118, the second sub-notch 115, the third sub-notch 116, and the fourth sub-notch 117) can fall within a range of 130 µm to 150 µm, which can result in a burst pressure difference of 2 KgF / mm 2 .

[0071] For example, referring to Figure 6 , a connection portion can be formed between each of the plurality of vent plates (e.g., the first vent plate 111, the second vent plate 112, the third vent plate 113, and the fourth vent plate 114) and the first notch (e.g., the first sub-notch 118, the second sub-notch 115, the third sub-notch 116, and the fourth sub-notch 117). The minimum thickness of the connection portion can be defined as the vertical distance between the second surface of each of the plurality of vent plates (e.g., the first vent plate 111, the second vent plate 112, the third vent plate 113, and the fourth vent plate 114) and the first surface of the first notch (e.g., the first sub-notch 118, the second sub-notch 115, the third sub-notch 116, and the fourth sub-notch 117). For example, as shown in FIG. 1A, the minimum thickness h1 of the connection portion formed between the third vent plate 113 and the second sub-notch 115 in the safety vent 110 can be defined as the vertical distance between the second surface 137 of the third vent plate 113 and the first surface 145 of the second sub-notch 115. Figure 6 For example, as shown in FIG. 1A, the minimum thickness h2 of the connection portion formed between the second vent plate 112 and the second sub-notch 115 in the safety vent 110 can be defined as the vertical distance between the second surface 135 of the second vent plate 112 and the first surface 145 of the second sub-notch 115. Figure 6 ​​

[0072] In an embodiment, a first minimum thickness of a connection portion formed between the first exhaust plate 111 and the first sub-recess 118, a second minimum thickness h2 of a connection portion formed between the second exhaust plate 112 and the second sub-recess 115, a third minimum thickness of a connection portion formed between the third exhaust plate 113 and the third sub-recess 116 (for example, equal to the minimum thickness h1 between the third exhaust plate 113 and the second sub-recess 115 in the case where the second sub-recess 115 and the third sub-recess 116 have the same depth), and a fourth minimum thickness of a connection portion formed between the fourth exhaust plate 114 and the fourth sub-recess 117 can be different from each other.

[0073] In an embodiment, the first minimum thickness of the connection portion formed between the first exhaust plate 111 and the first sub-recess 118, the second minimum thickness h2 of the connection portion formed between the second exhaust plate 112 and the second sub-recess 115, the third minimum thickness of the connection portion formed between the third exhaust plate 113 and the third sub-recess 116, and the fourth minimum thickness of the connection portion formed between the fourth exhaust plate 114 and the fourth sub-recess 117 can sequentially decrease (or, conversely, increase), and the minimum thickness between each exhaust plate and the recess can determine the burst pressure of each exhaust plate.

[0074] In an embodiment, the depths of the first sub-recess 118, the second sub-recess 115, the third sub-recess 116, and the fourth sub-recess 117 with respect to the first surface of each exhaust plate can be the same or can sequentially decrease or increase. Further, in an embodiment, the depths of the first sub-recess 118, the second sub-recess 115, the third sub-recess 116, and the fourth sub-recess 117 with respect to the first surface of each exhaust plate can be the same as the minimum thickness of the connection portion formed between each exhaust plate and the recess. Figures 3 to 6 In the illustrated example, the cross-section of each first recess has a rectangular shape. However, the cross-section of each first recess can have a V shape, a U shape, a semi-circular shape, etc.

[0075] In an embodiment, the side portions of the safety exhaust 110 can include a side portion 121 of the first exhaust plate 111, a side portion 123 of the second exhaust plate 112, a side portion 124 of the third exhaust plate 113, and a side portion 122 of the fourth exhaust plate 114, and the side portions of the respective exhaust plates can be coupled to the housing 160. The respective side portions of the safety exhaust 110 coupled to the housing 160 can have different thicknesses based on the thicknesses of the exhaust plates, which can affect the burst pressure of each exhaust plate.

[0076] In another embodiment, in a case where the side portions of each of the exhaust plates are coupled to the case 160, a second notch 119 can be provided between the case 160 and the side portions of each of the exhaust plates, and the second notch can determine the burst pressure of each of the exhaust plates. For example, the second notch can include a fifth sub-notch formed between the case 160 and the first exhaust plate 111, a sixth sub-notch formed between the case 160 and the second exhaust plate 112, a seventh sub-notch formed between the case 160 and the third exhaust plate 113, and an eighth sub-notch formed between the case 160 and the fourth exhaust plate 114. For example, the second notch can include a sub-notch formed between the case 160 and each of the side portions 121 to 124, e.g., a sub-notch formed as a groove in each of the side portions 121 to 124.

[0077] A connection portion can be formed between each of the plurality of exhaust plates (e.g., the first exhaust plate 111, the second exhaust plate 112, the third exhaust plate 113, and the fourth exhaust plate 114) and the second notch. A minimum thickness of the connection portion can be defined as a shortest distance between an edge at which the second notch contacts a second surface of each of the exhaust plates and an edge at which the case contacts a first surface of the second notch.

[0078] In an embodiment, a first minimum thickness of the connection portion formed between the first exhaust plate and the second notch (e.g., the fifth sub-notch), a second minimum thickness of the connection portion formed between the second exhaust plate and the second notch (e.g., the sixth sub-notch), a third minimum thickness of the connection portion formed between the third exhaust plate and the second notch (e.g., the seventh sub-notch), and a fourth minimum thickness of the connection portion formed between the fourth exhaust plate and the second notch (e.g., the eighth sub-notch) can be different from each other.

[0079] In an embodiment, a first minimum thickness of the connection portion formed between the first exhaust plate and the second notch (e.g., the fifth sub-notch), a second minimum thickness of the connection portion formed between the second exhaust plate and the second notch (e.g., the sixth sub-notch), a third minimum thickness of the connection portion formed between the third exhaust plate and the second notch (e.g., the seventh sub-notch), and a fourth minimum thickness of the connection portion formed between the fourth exhaust plate and the second notch (e.g., the eighth sub-notch) can sequentially decrease or increase.

[0080] For example, the first notch and the second notch can be provided at the same time. In this case, a minimum thickness of the connection portion between each of the first and second notches and each of the exhaust plates can determine the burst pressure of each of the exhaust plates. In another example, only one of the first notch or the second notch can be formed.

[0081] If all of the exhaust plates are ruptured at the same time, a significant increase in the discharge pressure from the secondary battery can be triggered in a short time. Such a large pressure increase in a short time can cause misalignment of the internal electrode assembly, which in turn can cause short circuiting of the electrode plates, resulting in thermal runaway. In contrast, according to an embodiment, the safety exhaust member 110 has a plurality of exhaust plates having different rupture pressures, so that the plurality of exhaust plates can be sequentially ruptured, for example, the safety exhaust member 100 can sequentially rupture in four stages in a clockwise direction, thereby reducing the possibility of the above-mentioned thermal runaway.

[0082] In an embodiment, as shown in Figure 3 , the safety exhaust member 110 can be radially divided into a first exhaust plate 111, a second exhaust plate 112, a third exhaust plate 113, and a fourth exhaust plate 114 from any point of the safety exhaust member 110. For example, the area of the safety exhaust member 110 can be divided radially from the center of the safety exhaust member 110 by the plurality of exhaust plates.

[0083] Figure 7 is a plan view illustrating a safety exhaust member according to an embodiment of the disclosure.

[0084] Referring to Figure 7 , the safety exhaust member 210 can include two exhaust plates, for example, a first exhaust plate 211 and a second exhaust plate 212. A first notch 213 can be formed between the first exhaust plate 211 and the second exhaust plate 212. In addition, or alternatively, a second notch can be formed between each exhaust plate and the housing.

[0085] In an embodiment, the first notch 213 separating the plurality of exhaust plates can not pass through the center of the safety exhaust member 210. For example, the first notch can pass through any point, and the areas of the respective exhaust plates can be different from each other.

[0086] In an embodiment, the thickness and area of each exhaust plate can vary, and the width, depth, and thickness of each of the first notch and the second notch and the minimum thickness of the connection portion of each of the first notch and the second notch can also vary.

[0087] For example, referring to Figure 7 , the first notch 213 can be formed in a direction parallel to the Y-axis direction. In another example, the first notch can be formed in a direction perpendicular to the Y-axis direction.

[0088] With this configuration, it is possible to artificially control the rupture pressure of the plurality of exhaust plates, thereby allowing each exhaust plate to have a different rupture pressure.

[0089] Figure 8 is a plan view illustrating a safety exhaust member according to an embodiment of the disclosure.

[0090] Referring toFigure 8 The safety vent 310 can include three vent plates, for example, a first vent plate 311, a second vent plate 312, and a third vent plate 313, which are separated from each other by a first notch. The first notch can include a first sub-notch formed between the first vent plate 311 and the second vent plate 312, a second sub-notch formed between the first vent plate 311 and the third vent plate 313, and a third sub-notch formed between the second vent plate 312 and the third vent plate 313.

[0091] In an embodiment, the thicknesses of the first sub-notch to the third sub-notch can be the same, and the first sub-notch to the third sub-notch can be formed at the same depth with respect to the first surfaces of the first vent plate 311, the second vent plate 312, and the third vent plate 313. A connection portion formed between the first vent plate 311 and the first sub-notch and the second sub-notch can have a first minimum thickness, a connection portion between the second vent plate 312 and the first sub-notch and the third sub-notch can have a second minimum thickness, and a connection portion formed between the third vent plate 313 and the second sub-notch and the third sub-notch can have a third minimum thickness.

[0092] With this configuration, the rupture pressure of the plurality of vent plates can be artificially adjusted, allowing each vent plate to have a different rupture pressure.

[0093] Figure 9 is a plan view illustrating a safety vent according to an embodiment of the disclosure.

[0094] Referring to Figure 9 The safety vent 410 can include a first vent plate 411, a second vent plate 412, a third vent plate 413, and a fourth vent plate 414. For ease of explanation, redundant descriptions of configurations identical to those discussed with reference to Figures 3 to 6 will be omitted.

[0095] Referring to Figure 9 The area (e.g., size and shape) of the first surface of each vent plate (e.g., the first vent plate 411, the second vent plate 412, the third vent plate 413, and the fourth vent plate 414) can be different from each other. For example, the area of the first vent plate 411 can be greater than the area of the second vent plate 412, the area of the second vent plate 412 can be greater than the area of the third vent plate 413, and the area of the third vent plate 413 can be greater than the area of the fourth vent plate 414. The area of the first surface of each vent plate can sequentially decrease.

[0096] For example, the length h5 of the first sub-notch, the length h4 of the second sub-notch, the length h6 of the third sub-notch, and the length h3 of the fourth sub-notch can be different from each other and can sequentially decrease. For example, the intersection points of the first and third sub-notches and the second and fourth sub-notches can be offset with respect to the center of the safety vent 410.

[0097] Figure 10 is a plan view illustrating a safety vent according to an embodiment of the disclosure.

[0098] Referring to Figure 10 , the safety vent 510 can include three vent plates, for example, a first vent plate 511, a second vent plate 512, and a third vent plate 513. For ease of explanation, redundant descriptions of configurations identical to those discussed with reference to Figures 3 to 6 will be omitted.

[0099] For example, the safety vent 510 can include a plurality of vent plates arranged side by side in one direction, for example, along the Y-axis direction in Figure 10 In an embodiment, a first sub-notch can be formed between the first vent plate 511 and the second vent plate 512, and a second sub-notch can be formed between the second vent plate 512 and the third vent plate 513. For example, the first and second sub-notches can be parallel to each other. In another example, the first and second sub-notches can be formed so as not to intersect each other on the first surfaces of the vent plates.

[0100] By way of summary and review, when a secondary battery is continuously exposed to high temperatures or is charged or discharged at a high current, internal gas can be generated due to cell degradation and other factors. In this regard, the internal gas generated in the secondary battery can cause an increase in internal pressure within the case. As a result, the electrode assembly within the case can be damaged, thereby incurring a risk of fire. As a countermeasure to this, various efforts have been made to suppress melting of internal components or to prevent fire due to damage of internal components of the secondary battery.

[0101] According to some embodiments of the disclosure, a safety vent can include a plurality of vent plates each having a different rupture pressure. Each vent plate can be configured to rupture in response to a case in which the internal pressure exceeds the rupture pressure of each vent plate. This configuration allows the plurality of vent plates of the safety vent to sequentially rupture, thereby increasing the release area during the time required for the internal gas generated due to the charging and discharging processes to burn.

[0102] According to some embodiments of the disclosure, the plurality of exhaust plates of the safety exhaust member can sequentially break from an exhaust plate having the lowest break pressure among the plurality of exhaust plates. By enabling the plurality of exhaust plates forming the safety exhaust member to sequentially break, pressure changes in a short time can be reduced, while damage to the electrode assembly and short circuit of the electrode plate can be prevented.

[0103] According to some embodiments of the disclosure, the thickness and area of each exhaust plate constituting the safety exhaust member can vary. Further, the width, depth, and thickness of each of the first and second notches and the minimum thickness of the connecting portion can also vary. This allows the break pressure of the plurality of exhaust plates to be adjusted in various ways according to design requirements, such that each exhaust plate has a different break pressure.

[0104] However, aspects and features of the disclosure are not limited to those described above, and other aspects and features not mentioned will be clearly understood by those skilled in the art through the above detailed description.

[0105] While the disclosure has been described above with reference to the embodiments of the disclosure, the disclosure is not limited thereto. Those skilled in the art can make various modifications and variations to the disclosure within the spirit and scope of the claims.

[0106] Example embodiments have been disclosed herein, although specific terminology has been used to describe them, they are used in a generic and descriptive sense only and not for purposes of limitation. In some instances, features, attributes and / or elements described in conjunction with a particular example embodiment are likewise applicable to other example embodiments, except where stated otherwise. Thus, unless specifically set forth otherwise, features, attributes and / or elements described in conjunction with a particular example embodiment can be used in combination with features, attributes and / or elements described in conjunction with any other example embodiment, even though not specifically stated in connection therewith. As such, it will be understood that various changes can be made in the form, details, and / or proportions of certain components without departing from the spirit and essential characteristics of the application.

Claims

1. A secondary battery, comprising: The electrode assembly includes a first electrode, a diaphragm, and a second electrode; Housing that houses the electrode assembly; A cover plate, connected to the opening of the housing; as well as A safety vent, located on one side of the housing and the cover, the safety vent comprising a plurality of vent plates, each of the plurality of vent plates having a different burst pressure.

2. The secondary battery according to claim 1, wherein the thicknesses of the plurality of vent plates are different from each other.

3. The secondary battery according to claim 1, wherein the areas of the plurality of exhaust plates are different from each other.

4. The secondary battery according to claim 1, wherein the safety venting member includes a first recess between adjacent venting plates in the plurality of venting plates.

5. The secondary battery according to claim 4, wherein the connection portion between each of the plurality of vent plates and the first recess has a different minimum thickness.

6. The secondary battery of claim 1, wherein the safety venting member includes a second recess between each of the plurality of venting plates and one of the housing and the cover plate.

7. The secondary battery of claim 6, wherein the connection portion between each of the plurality of vent plates and the second recess has a different minimum thickness.

8. The secondary battery according to claim 1, wherein the plurality of venting plates includes a first venting plate, a second venting plate, a third venting plate, and a fourth venting plate.

9. The secondary battery according to claim 8, wherein the safety vent is radially divided from any point of the safety vent to define the first vent plate, the second vent plate, the third vent plate, and the fourth vent plate.

10. The secondary battery according to claim 8, wherein the thickness of the first vent plate is greater than the thickness of the second vent plate, the thickness of the second vent plate is greater than the thickness of the third vent plate, and the thickness of the third vent plate is greater than the thickness of the fourth vent plate.

11. The secondary battery according to claim 8, wherein the safety venting device comprises: The first sub-notch is located between the first exhaust plate and the second exhaust plate; The second sub-recess is located between the second exhaust plate and the third exhaust plate; The third sub-notch is located between the third exhaust plate and the fourth exhaust plate; as well as The fourth sub-notch is located between the fourth exhaust plate and the first exhaust plate.

12. The secondary battery according to claim 11, wherein the first minimum thickness of the connection portion between the first vent plate and the first sub-recess, the second minimum thickness of the connection portion between the second vent plate and the second sub-recess, the third minimum thickness of the connection portion between the third vent plate and the third sub-recess, and the fourth minimum thickness of the connection portion between the fourth vent plate and the fourth sub-recess sequentially decrease or increase.

13. The secondary battery according to claim 8, wherein the safety venting device comprises: The fifth sub-notch is located between the first exhaust plate and one of the housing and the cover plate; A sixth recess is located between the second exhaust plate and one of the housing and the cover plate; The seventh recess is located between the third exhaust plate and one of the housing and the cover plate; as well as The eighth recess is located between the fourth exhaust plate and one of the housing and the cover plate.

14. The secondary battery according to claim 13, wherein the first minimum thickness of the connection portion between the first vent plate and the fifth sub-recess, the second minimum thickness of the connection portion between the second vent plate and the sixth sub-recess, the third minimum thickness of the connection portion between the third vent plate and the seventh sub-recess, and the fourth minimum thickness of the connection portion between the fourth vent plate and the eighth sub-recess sequentially decrease or increase.

15. The secondary battery according to claim 11, wherein the first sub-notch, the second sub-notch, the third sub-notch, and the fourth sub-notch have the same thickness.

16. The secondary battery according to claim 11, wherein the first sub-notch, the second sub-notch, the third sub-notch and the fourth sub-notch have different thicknesses.

17. The secondary battery according to claim 11, wherein the first surfaces of the first vent plate, the second vent plate, the third vent plate and the fourth vent plate are coplanar with each other.

18. The secondary battery of claim 17, wherein the first sub-recess, the second sub-recess, the third sub-recess, and the fourth sub-recess have the same depth relative to the first surface of the first vent plate.

19. The secondary battery according to claim 17, wherein the second surfaces of the first vent plate, the second vent plate, the third vent plate and the fourth vent plate are not coplanar with each other, and the second surfaces are opposite to the first surfaces.

20. The secondary battery according to claim 1, wherein the plurality of exhaust plates are arranged side by side in one direction.

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