Secondary battery

Abstract

There is provided a secondary battery including: a first electrode plate including a first substrate having a first active material coated portion coated with a first active material and a first electrode uncoated portion not coated with the first active material; a second electrode plate including a second substrate having a second active material coated portion coated with a second active material and a second electrode uncoated portion not coated with the second active material; a separator between the first electrode plate and the second electrode plate; an electrode tab connected to one of the first electrode uncoated portion and the second electrode uncoated portion; an insulating tape on the first electrode uncoated portion or the second electrode uncoated portion and covering the electrode tab; and a step compensation unit on a region of the upper surface of the insulating tape other than a region corresponding to the electrode tab.

Description

[0001] This application claims priority to and the benefit of Korean Patent Application No. 10-2023-0121023 filed in the Korean Intellectual Property Office on September 12, 2023, the disclosure of which is incorporated herein in its entirety by reference. Technical Field

[0002] Aspects of embodiments of the present disclosure relate to a secondary battery. Background Art

[0003] Unlike primary batteries that are designed not to be recharged, secondary batteries are batteries that are designed to be (re)charged and discharged. Low-capacity secondary batteries packaged in the form of a group including a single battery cell are widely used in portable small electronic devices such as cellular phones or cameras. In some embodiments, large-capacity secondary batteries packaged in the form of a battery pack including dozens of battery cells connected to each other are widely used to drive motors of hybrid vehicles, etc.

[0004] Secondary batteries are manufactured in various shapes, and their typical shapes include a pouch shape, a cylindrical shape, and a square (or prism) shape. The secondary battery is constructed by including an electrode assembly formed by placing an insulating separator between positive and negative electrode plates and an electrolyte in a case.

[0005] In some cylindrical secondary batteries, depending on the condition of the core electrode assembly and the thickness of the electrode tab, pressure may be applied to the substrate at the edge of the electrode tab. The stress caused by the pressure may cause cracks along the boundary area of ​​the electrode tab, and in severe cases, even rupture or damage. Summary of the invention

[0006] Embodiments of the present disclosure provide a secondary battery capable of compensating for pressure applied to an electrode tab by attaching a tape having the same thickness (or thickness level) as the electrode tab to an electrode uncoated portion (eg, a portion of the electrode not coated with an active material) around the electrode tab.

[0007] A secondary battery according to an embodiment of the present disclosure includes: a first electrode plate, including a first substrate having a first active material coating portion coated with a first active material and a first electrode uncoated portion not coated with the first active material; a second electrode plate, including a second substrate having a second active material coating portion coated with a second active material and a second electrode uncoated portion not coated with the second active material; a diaphragm, between the first electrode plate and the second electrode plate; an electrode tab, connected to one of the first electrode uncoated portion and the second electrode uncoated portion; an insulating tape, on the first electrode uncoated portion or the second electrode uncoated portion, and covering the electrode tab; and a step compensation unit, on an area of ​​the upper surface of the insulating tape except for an area corresponding to the electrode tab.

[0008] The step compensation unit may include a first step compensation unit on both ends of the insulating tape at an upper surface of the insulating tape.

[0009] The step compensation unit may further include a second step compensation unit on a region of the insulating tape between the first step compensation units and not corresponding to the electrode tab.

[0010] The first step compensation units may be connected to each other with the second step compensation unit therebetween.

[0011] The step compensation unit may have a width extending from one end of the electrode tab to one end of the insulating tape.

[0012] The insulating tape may be on the upper surface of the first electrode plate to cover a portion of the first active material coating portion, the electrode tab, and the first electrode uncoated portion, or may be on the upper surface of the second electrode plate to cover a portion of the second active material coating portion, the electrode tab, and the second electrode uncoated portion.

[0013] The thickness T2 of the step compensation unit may be in the range of 0.1×T1≤T2≤1.5×T1, where T1 is the thickness of the electrode tab.

[0014] When the thickness of the first layer including the first substrate, the first active material coating portion and the insulating tape is different from the thickness of the second layer including the first substrate, the electrode terminal and the insulating tape, the step compensation unit may have a thickness that gradually decreases or increases in the direction from the first layer to the second layer; or, when the thickness of the third layer including the second substrate, the second active material coating portion and the insulating tape is different from the thickness of the fourth layer including the second substrate, the electrode terminal and the insulating tape, the step compensation unit may have a thickness that gradually decreases or increases in the direction from the third layer to the fourth layer.

[0015] An insulating tape may be additionally arranged in the same shape on the lower surface of the first electrode uncoated portion or the second electrode uncoated portion opposite to the upper surface to which the electrode terminal is connected at a position corresponding to the upper surface; and a step compensation unit may be additionally arranged in the same shape on the lower surface of the insulating tape arranged on the lower surface of the first electrode uncoated portion or the second electrode uncoated portion at a position corresponding to its position on the upper surface of the insulating tape.

[0016] The total thickness (T2+T3) of the step compensation unit may be within the range of 0.1×T1≤T2+T3≤1.5×T1, where T1 is the thickness of the electrode tab, T2 is the thickness of the step compensation unit on the upper surface of the first electrode uncoated portion or the second electrode uncoated portion, and T3 is the thickness of the step compensation unit on the lower surface of the first electrode uncoated portion or the second electrode uncoated portion.

[0017] The step compensation unit may include an adhesive tape including a film and an adhesive layer on a lower surface of the film.

[0018] The film may include polyimide, polyethylene terephthalate, or polypropylene, and the adhesive layer may include an acrylic compound, a rubber compound, or a hydrocarbon resin compound. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 , Figure 2 and Figure 3 1 and 2 are a perspective view, an exploded perspective view, and a cross-sectional view, respectively, of a secondary battery according to an embodiment of the present disclosure.

[0020] Figure 4 is a cross-sectional view of a step compensation unit formed on an upper portion of a first electrode plate according to an embodiment of the present disclosure.

[0021] Figure 5 It is shown Figure 4 A plan view of the width and length range of the step compensation unit shown in FIG.

[0022] Figure 6 is a cross-sectional view of an embodiment in which step compensation units formed on a first electrode plate have different thicknesses.

[0023] Figure 7 is a cross-sectional view of a step compensation unit formed on an upper portion and a lower portion of a first electrode plate according to an embodiment of the present disclosure.

[0024] Figure 8 is a diagram illustrating a cross-sectional configuration of a step compensation unit according to an embodiment of the present disclosure.

[0025] Fig. 9is a cross-sectional view of a step compensation unit formed on an upper portion of a second electrode plate according to an embodiment of the present disclosure.

[0026] Fig.10 yes Fig. 9 A plan view of the width and length range of the step compensation unit shown in FIG.

[0027] Fig.11 is a cross-sectional view of an embodiment in which step compensation units formed on a second electrode plate have different thicknesses.

[0028] Fig.12 is a cross-sectional view of a step compensation unit formed on the top and bottom of a second electrode plate according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0029] The embodiments of the present disclosure are provided to more completely explain the aspects and features of the present disclosure to those skilled in the art, and the following embodiments may be modified in various other forms. However, the present disclosure may be implemented in many different forms and should not be construed as being limited to the embodiments set forth herein. On the contrary, these embodiments are provided so that the present disclosure will be thorough and complete, and will convey the aspects and features of the present disclosure to those skilled in the art.

[0030] It will be understood that when an element or layer is referred to as being "on," "connected to," or "coupled to" another element or layer, it may be directly on, directly connected to, or directly coupled to the other element or layer, or one or more intervening elements or layers may also 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 "coupled to" a second element, the first element may be directly coupled to or directly coupled to the second element, or the first element may be indirectly coupled to or indirectly coupled to the second element via one or more intervening elements.

[0031] In the figure, for the clarity of the illustration, the size of various elements, layers, etc. can be exaggerated. The same reference numerals represent the same elements. As used herein, the term "and / or" includes any combination and all combinations of one or more of the relevant listed items. In addition, when describing the embodiments of the present disclosure, the use of "may" relates to "one or more embodiments of the present disclosure". Expressions such as "at least one (kind / person) in ... " and "any one (kind / person) in ... " modify the entire column of elements when they are after a column of elements, without modifying the individual elements in the column. For example, the expression "at least one (kind / person) in a, b, and c" means only a, only b, only c, a and b, a and c, b and c, a, b, and c, all or their variations. As used herein, the term "use" and its variations can be considered to be synonymous with the term "utilize" and its variations, respectively. As used herein, the terms "substantially (substantially)", "approximately (about)" and similar terms are used as approximate terms rather than as terms of degree, and are intended to explain the inherent deviations of measured values ​​or calculated values ​​that will be recognized by those of ordinary skill in the art.

[0032] It will be understood that, although the terms first, second, third, etc. can be used to describe various elements, components, regions, layers and / or parts, these elements, components, regions, layers and / or parts should not be limited by these terms. These terms are used to distinguish an element, component, region, layer or part from another element, component, region, layer or part. Therefore, without departing from the teaching of the exemplary embodiment, the first element, first component, first region, first layer or first part discussed below can be referred to as the second element, second component, second region, second layer or second part.

[0033] For ease of description, spatially relative terms such as "under", "below", "below", "above", "on", etc. may be used herein to describe the relationship of one element or feature to another element or features as shown in the figure. It will be understood that, in addition to the orientation depicted in the figure, the spatially relative terms are intended to cover different orientations of the device in use or operation. For example, if the device in the figure is turned over, the element described as "below" or "below" other elements or features will then be oriented to be "above" or "on" the other elements or features. Therefore, the term "below" can cover both above and below. The device can be oriented otherwise (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0034] 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 forms "one" and "one (kind / person)" are also intended to include plural forms. It will also be understood that when the terms "include", "comprise" and / or its variations are used in this specification, the stated features, integers (entirety), steps, operations, elements and / or components are indicated, but the presence or addition of one or more other features, integers (entirety), steps, operations, elements, components and / or their groups are not excluded.

[0035] Hereinafter, a secondary battery 100 according to an embodiment of the present disclosure will be described in detail with reference to the accompanying drawings.

[0036] Figure 1 , Figure 2 and Figure 3 1 and 2 are a perspective view, an exploded perspective view, and a cross-sectional view, respectively, of a secondary battery according to an embodiment of the present disclosure.

[0037] Reference Figure 1 , Figure 2 and Figure 3 , the secondary battery 100 according to an embodiment of the present disclosure may include a cylindrical can 110, a cylindrical electrode assembly 120, an upper insulating plate 150, a lower insulating plate 160, and a cap assembly 190, and with reference to Figures 4 to 12 , an insulating tape 170 and a step compensation unit 180 may further be included.

[0038] The can 110 may have a circular bottom 111 and a cylindrical side portion 112 extending upward by a length (e.g., a certain length) from the bottom 111. During the manufacturing process of the secondary battery 100, the top (or top end) of the cylindrical can 110 may be open. Therefore, during the assembly process of the secondary battery 100, the electrode assembly 120 may be inserted into the cylindrical can 110 together with the electrolyte through the open portion (or open end).

[0039] The cylindrical can 110 may include steel, steel alloy, aluminum, aluminum alloy, or its equivalent (or may be formed of steel, steel alloy, aluminum, aluminum alloy, or its equivalent). In the embodiment shown, the can may include or may be referred to as a shell or housing. In the embodiment shown, in order to prevent the electrode assembly 120 and the cap assembly 190 from being separated to the outside, the cylindrical can 110 may have a curling portion (e.g., curling) 113 that is inwardly concave at the lower portion of the cap assembly 190 (e.g., below the cap assembly 190) and a crimping portion (e.g., crimping end) 114 that is bent inwardly at the upper portion of the cap assembly 190 (e.g., above the cap assembly 190).

[0040] The electrode assembly 120 may be housed inside the cylindrical can 110. The electrode assembly 120 may include a first electrode plate 121, a second electrode plate 122, and a separator 123. In the illustrated embodiment, the first electrode plate 121 may be a positive electrode plate, and the second electrode plate 122 may be a negative electrode plate. However, in other embodiments, the opposite is possible. Hereinafter, for ease of explanation, an embodiment in which the first electrode plate 121 is a positive electrode plate and the second electrode plate 122 is a negative electrode plate will be described.

[0041] The electrode assembly 120 may include a first active material coating portion 121a (see FIG. 1 ) having a substrate coated with a positive electrode active material (eg, a transition metal oxide such as LiCoO 2 , LiNiO 2 , LiMn 2 O 4 , etc.). Figure 4 ) having a positive electrode plate 121, a second active material coating portion 122a (see Fig. 9 ) and a separator 123 between the positive electrode plate 121 and the negative electrode plate 122 to prevent a short circuit while allowing lithium ions to move. Hereinafter, for convenience of explanation, the first active material coating portion 121a and the second active material coating portion 122a will be described as a positive electrode active material coating portion 121a and a negative electrode active material coating portion 122a, respectively.

[0042] The positive electrode plate 121, the negative electrode plate 122, and the separator 123 may be wound into a substantially cylindrical shape. In the illustrated embodiment, the positive electrode plate 121 may include an aluminum (Al) foil, the negative electrode plate 122 may include a copper (Cu) foil or a nickel (Ni) foil, and the separator 123 may include polyethylene (PE) or polypropylene (PP).

[0043] As described above, the positive electrode plate 121 may be a plate-shaped metal foil made of aluminum (Al) and coated with a positive electrode active material made of a transition metal oxide on at least one surface. The positive electrode plate 121 may have a first electrode non-coating portion 121b (see FIG. 1 ) at an upper end where the positive electrode active material is not coated. Figure 4 ). The first electrode uncoated portion 121b may protrude upward from the electrode assembly 120. For example, the first electrode uncoated portion 121b of the positive electrode plate 121 may protrude upward further than the negative electrode plate 122 and the separator 123 (e.g., the first electrode uncoated portion 121b of the positive electrode plate 121 may protrude upward beyond the negative electrode plate 122 and the separator 123 or protrude above the negative electrode plate 122 and the separator 123).

[0044] As described above, the negative electrode plate 122 may be a plate-shaped metal foil made of copper (Cu) or nickel (Ni), and coated with a negative electrode active material made of graphite or carbon on at least one surface. The negative electrode plate 122 may have a second electrode non-coating portion 122b (see FIG. 1 ) at a lower end where the negative electrode active material is not coated. Fig. 9 ). The second electrode uncoated portion 122b may protrude downward from the electrode assembly 120. For example, the second electrode uncoated portion 122b of the negative electrode plate 122 may protrude downward further than the positive electrode plate 121 and the separator 123 (e.g., the second electrode uncoated portion 122b of the negative electrode plate 122 may protrude downward more than the positive electrode plate 121 and the separator 123 or protrude below the positive electrode plate 121 and the separator 123).

[0045] The first electrode uncoated portion 121b may be a positive electrode uncoated portion, and the second electrode uncoated portion 122b may be a negative electrode uncoated portion, but in other embodiments, the opposite is possible. Hereinafter, for ease of explanation, an embodiment in which the first electrode uncoated portion 121b is a positive electrode uncoated region, and the second electrode uncoated portion 122b is a negative electrode uncoated region will be described.

[0046] In the illustrated embodiment, the positive electrode non-coating portion 121b of the positive electrode plate 121 may include a first electrode tab 141 protruding upward by a length (see FIG. Figure 4 ), the negative electrode non-coating portion 122b of the negative electrode plate 122 may include a second electrode tab 142 protruding downward by a certain length (see Fig. 9 ), but in other embodiments the opposite is possible.

[0047] In the illustrated embodiment, the first electrode tab 141 is cut from the positive electrode uncoated portion 121b, and thus may include the same material as the positive electrode uncoated portion 121b, for example, aluminum. In some embodiments, the second electrode tab 142 is cut from the negative electrode uncoated portion 122b, and thus may include the same material as the negative electrode uncoated portion 122b, for example, copper or nickel. The first electrode tab 141 may be a positive electrode tab, and the second electrode tab 142 may be a negative electrode tab. However, in other embodiments, the opposite is possible. Hereinafter, for ease of explanation, an embodiment in which the first electrode tab 141 is a positive electrode tab and the second electrode tab 142 is a negative electrode tab will be described. The positive electrode tab 141 of the electrode assembly 120 may be connected to the cap assembly 190, and the negative electrode tab 142 may be connected to the bottom 111 of the cylindrical can 110. The positive electrode tab 141 located at the upper side and the cap assembly 190 may be electrically connected by a first lead tab 141a welded to the positive electrode tab 141. In some embodiments, the negative electrode tab 142 and the bottom 111 may be electrically connected to a second lead tab 142a welded to the negative electrode tab 142. In some embodiments, the positive electrode tab 141 and the cap assembly 190 may be connected by the first lead tab 141a, and the negative electrode tab 142 and the bottom 111 may be directly connected without a separate lead tab, but in other embodiments, the opposite is possible.

[0048] The electrode assembly 120 may be referred to as an electrode group or an electrode. In the illustrated embodiment, as described above, the negative electrode tab 142 of the electrode assembly 120 may be welded to the bottom 111 of the cylindrical can 110, or may be connected to the second lead tab 142a. Thus, the cylindrical can 110 may be used as a negative electrode. For example, conversely, the positive electrode tab 141 may be connected to the bottom 111 of the cylindrical can 110, and in this embodiment, the cylindrical can 110 may be used as a positive electrode.

[0049] The upper insulating plate 150 is coupled to the cylindrical can 110 and may have a first hole 150a formed in the center thereof and a plurality of second holes 150b formed outside (e.g., around) the first hole 150a. In some embodiments, the upper insulating plate 150 may be interposed between the electrode assembly 120 and the cap assembly 190. The upper insulating plate 150 may prevent the electrode assembly 120 from electrically contacting the cap assembly 190. In the illustrated embodiment, the upper insulating plate 150 may prevent the positive electrode plate 121 of the electrode assembly 120 from electrically contacting the cap assembly 190.

[0050] When a large amount of gas is generated due to an abnormality in the secondary battery 100, the first hole 150a may allow the gas to quickly move toward the cap assembly 190. In the illustrated embodiment, the second hole 150b may allow the positive electrode tab 141 or the first lead tab 141a to pass through the upper insulating plate 150 to be welded to the cap assembly 190. In some embodiments, the remaining second holes 150b allow the electrolyte to quickly flow into the electrode assembly 120 during the electrolyte injection process.

[0051] The lower insulating plate 160 is coupled to the cylindrical can 110 and may have a first hole 160a at the center thereof and a second hole 160b formed outside the first hole 160a (e.g., offset from the first hole 160a). In some embodiments, the lower insulating plate 160 may be interposed between the electrode assembly 120 and the bottom 111. The lower insulating plate 160 may prevent the electrode assembly 120 from electrically contacting the bottom 111 of the cylindrical can 110. In the illustrated embodiment, the lower insulating plate 160 may prevent the negative electrode plate 122 of the electrode assembly 120 from electrically contacting the bottom 111.

[0052] When a large amount of gas is generated due to an abnormality in the secondary battery, the first hole 160a may allow the gas to quickly move upward (or downward). In some embodiments, the second hole 160b may allow the negative electrode tab 142 or the second lead tab 142a to pass through the lower insulating plate 160 to be welded to the bottom 111.

[0053] The insulating tape 170 may include a first insulating tape 171 (see Figure 4 ) and the second insulating tape 172 (see Fig. 9 ). In one embodiment, the first insulating tape 171 is attached to a portion of the positive electrode tab 141 of the positive electrode plate 121, and the second insulating tape 172 is attached to a portion of the negative electrode tab 142 of the negative electrode plate 122. A more detailed description of the insulating tape 170 will be provided later.

[0054] The cap assembly 190 may include an upper cap 191 having a plurality of through holes (e.g., openings) 191a, a safety vent 192 located below the upper cap 191, and a connecting ring 193 and a lower cap 194 both located below the safety vent 192. In the illustrated embodiment, the lower cap 194 is located below the safety vent 192 and the connecting ring 193, has a plurality of through holes 194a, and may be electrically connected to the positive electrode tab 141 or the first lead tab 141a. In the illustrated embodiment, the cap assembly 190 may further include an insulating gasket 195 that insulates the upper cap 191, the safety vent 192, and the lower cap 194 from the side 112 of the cylindrical can 110. The insulating gasket 195 may be substantially compressed between the crimping portion 113 and the crimping portion 114 formed in the side 112 of the cylindrical can 110. In the illustrated embodiment, when abnormal internal pressure occurs inside the cylindrical can 110, the through holes 191a in the upper cover 191 and the through holes 194a in the lower cover 194 may discharge internal gas to the outside.

[0055] In addition, the gas causing such abnormal internal pressure passes upward through the through hole 194a in the lower cover 194 and flips the safety vent 192, so the safety vent 192 can be electrically separated from the lower cover 194. Subsequently, the safety vent 192 is torn (e.g., opened or burst), and the internal gas can be released to the outside through the through hole 191a in the upper cover 191.

[0056] The electrolyte may be injected into the cylindrical can 110. This allows lithium ions generated by the electrochemical reaction to move between the negative electrode plate 122 and the positive electrode plate 121 inside the battery during charging and discharging. The electrolyte may include a non-aqueous organic electrolyte that is a mixture of a lithium salt and a high-purity organic solvent. In some embodiments, the electrolyte may include a polymer electrolyte or a solid electrolyte using a polymer.

[0057] Figure 4 is a cross-sectional view of a step compensation unit formed on an upper portion of a first electrode plate according to an embodiment of the present disclosure, Figure 5 It is shown Figure 4 A plan view of the width and length range of the step compensation unit shown in, Figure 6 is a cross-sectional view of an embodiment in which a step compensation unit formed on a first electrode plate has different thicknesses according to an embodiment of the present disclosure, Figure 7 is a cross-sectional view of a step compensation unit formed on an upper portion and a lower portion of a first electrode plate according to an embodiment of the present disclosure, and Figure 8 is a diagram illustrating a cross-sectional configuration of a step compensation unit according to an embodiment of the present disclosure.

[0058] like Figure 4As shown in , the step compensation unit 180 may be formed on a region (eg, a portion) of the upper surface of the insulating tape 170 excluding a region corresponding to (or overlapping) the positive electrode tab 141 .

[0059] For example, the step compensation unit 180 may include a first step compensation unit 181 and a second step compensation unit 182. Figure 5 as shown in .

[0060] The first step compensation unit 181 may be formed at both ends of the insulating tape 170 and on the upper surface of the insulating tape 170. The second step compensation unit 182 may be formed on an area of ​​the area between the first step compensation units 181 that does not correspond to the positive electrode tab 141 (e.g., deviates from the positive electrode tab 141). Therefore, in the step compensation unit 180, the first step compensation unit 181 formed at both sides of the positive electrode tab 141 and the second step compensation unit 182 connecting the first step compensation unit 181 (or extending between the first step compensation units 181) may be integrated (or integrally formed). In such an embodiment, the step compensation unit 180 may have a substantially "U" shape, but the planar structure of the step compensation unit 180 is not limited to this shape and may be modified to various shapes.

[0061] The width W1 of the first step compensation unit 181 may be within a range from one end a1 of the positive electrode tab 141 to one end a2 of the insulating tape 170 (or spanning or extending from one end a1 of the positive electrode tab 141 to one end a2 of the insulating tape 170). The insulating tape 170 may be formed on the upper surface of the positive electrode plate 121 to cover a portion of the positive electrode active material coating portion 121a, the positive electrode tab 141, and the first electrode non-coating portion 121b. In this way, the width W1 of the first step compensation unit 181 may be limited so that it reaches (or extends to) one end a2 of the insulating tape 170 while not overlapping the positive electrode tab 141, but the width W1 of the first step compensation unit 181 may be within a range between the end a3 of the first electrode non-coating portion 121b while not overlapping the positive electrode tab 141. The length L1 of the first step compensation unit 181 is not limited, but may be within a range between the upper end and the lower end of the insulating tape 170. A width W2 of the second step compensation unit 182 may be approximately the width of the positive electrode tab 141 , and a length L2 of the second step compensation unit 182 may be within a range between a lower end of the positive electrode tab 141 and a lower end of the insulating tape 170 .

[0062] The step compensation unit 180 compensates for the thickness of a relatively thin portion around the positive electrode tab 141 caused by the positive electrode tab 141 (for example, the step compensation unit 180 compensates for a relatively thin portion of the electrode assembly 120 where there is no coating portion and the electrode tab), and the upper surface of the step compensation unit 180 may be aligned with the upper surface A of the insulating tape 170 corresponding to the positive electrode tab 141, but may be relatively lower or higher than the upper surface A of the insulating tape 170. For example, as Figure 4 As shown in , the thickness T2 of the step compensation unit 180 may be in the range of about 0.1×T1≤T2≤1.5×T1, where T1 is the thickness of the positive electrode tab 141.

[0063] When the thickness T2 of the step compensation unit 180 is too thick (exceeding about 150%) compared to the thickness T1 of the positive electrode tab 141, the battery capacity may be reduced, which may be disadvantageous, and the step compensation unit 180 may exert pressure on the positive electrode substrate. Therefore, in consideration of the tolerance of the step compensation unit 180, the positive electrode tab 141 may be formed to reach about 150% of the thickness T1. In some embodiments, when the step compensation unit 180 is thinner than the positive electrode tab 141, there will be no problem, but in order to allow the effect of the step compensation unit 180 to be fully demonstrated, the thickness T2 of the step compensation unit 180 may be at least about 10% of the thickness T1 of the positive electrode tab 141.

[0064] like Figure 6 As shown in , in the positive electrode plate 121, when the thickness Ta of the first layer M1 including the positive electrode substrate, the positive electrode active material coating portion 121a and the insulating tape 170 is different from the thickness Tb of the second layer M2 including the positive electrode substrate, the positive electrode terminal tab 141 and the insulating tape 170, the step compensation unit 180 can be formed to have a thickness that gradually decreases or gradually increases in the direction from the first layer M1 to the second layer M2, so that its cross-section can be formed to be inclined.

[0065] For example, when the thickness Ta of the first layer M1 is greater than the thickness Tb of the second layer M2, the step compensation unit 180 may be formed to have a thickness that gradually decreases in a direction from the first layer M1 to the second layer M2. Figure 6 In the step compensation unit 180 shown in FIG. 1 , a thickness T21 of a left portion thereof is greater than a thickness T22 of a right portion thereof.

[0066] On the contrary, when the thickness Ta of the first layer M1 is less than the thickness Tb of the second layer M2, the step compensation unit 180 may be formed to have a thickness gradually increasing in a direction from the first layer M1 to the second layer M2. In such an embodiment, the thickness T21 of the left portion of the step compensation unit 180 may be less than the thickness T22 of the right portion thereof.

[0067] In some embodiments, for example, Figure 7 As shown in , the insulating tape 170 may be additionally formed in the same shape on the lower surface of the first electrode non-coating portion 121b opposite to the upper surface to which the positive electrode tab 141 is connected at a position corresponding to the upper surface. In such an embodiment, the step compensation unit 180 may also be formed in the same shape on the lower surface of the insulating tape 170 formed on the lower surface of the first electrode non-coating portion 121b at a position corresponding to its position on the upper surface of the insulating tape 170. The total thickness (T2+T3) of the step compensation unit 180 may be in the range of about 0.1×T1≤T2+T3≤1.5×T1. Here, T1 is the thickness of the positive electrode tab 141, T2 is the thickness of the step compensation unit 180 formed on the upper surface of the first electrode non-coating portion 121b, and T3 is the thickness of the step compensation unit 180 formed on the lower surface of the first electrode non-coating portion 121b.

[0068] The step compensation unit 180 may be an adhesive tape including a film F and an adhesive layer P formed on a lower surface of the film F. The film F may include a polyimide (PI), polyethylene terephthalate (PET), or polypropylene (PP) material, and the adhesive layer P may include an adhesive including at least one of an acrylic compound, a rubber compound, and a hydrocarbon resin compound.

[0069] Fig. 9 is a cross-sectional view of a step compensation unit formed on an upper portion of a second electrode plate according to an embodiment of the present disclosure, Fig.10 It is shown Fig. 9 A plan view of the width and length range of the step compensation unit shown in, Fig.11 is a cross-sectional view of an embodiment in which a step compensation unit formed on a second electrode plate is formed to have different thicknesses, and Fig.12 is a cross-sectional view of a step compensation unit formed on the top and bottom of a second electrode plate according to an embodiment of the present disclosure.

[0070] like Fig. 9 As shown in , the step compensation unit 180 may be formed on a region of the upper surface of the insulating tape 170 except for an upper surface B corresponding to the negative electrode tab 142 .

[0071] For example, Fig.10 As shown in , the step compensation unit 180 may include a first step compensation unit 181 and a second step compensation unit 182 .

[0072] The first step compensation unit 181 may be formed on the upper surface of the insulating tape 170 at both ends of the insulating tape 170. The second step compensation unit 182 may be formed at an area between the first step compensation units 181 on an area that does not correspond to the negative electrode tab 142 (e.g., deviates from the negative electrode tab 142). Therefore, in the step compensation unit 180, the first step compensation unit 181 formed at both sides of the negative electrode tab 142 and the second step compensation unit 182 connecting the first step compensation unit 181 (or extending between the first step compensation units 181) may be integrated (or integrally formed). The step compensation unit 180 may have an approximately "U" shape, but the planar structure of the step compensation unit 180 is not limited to this shape and may be modified to various shapes.

[0073] The width W1 of the first step compensation unit 181 may be within a range from one end a1 of the negative electrode tab 142 to one end a2 of the insulating tape 170 (or spanning or extending from one end a1 of the negative electrode tab 142 to one end a2 of the insulating tape 170). The insulating tape 170 may be formed on the upper surface of the negative electrode plate 122 to cover a portion of the negative electrode active material coating portion 122a, the negative electrode tab 142, and the second electrode non-coating portion 122b. In this way, the width W1 of the first step compensation unit 181 may be limited to a range that reaches (or extends to) one end a2 of the insulating tape 170 while not overlapping the negative electrode tab 142, but the width W1 of the first step compensation unit 181 may be within a range between the end a3 of the second electrode non-coating portion 122b while not overlapping the negative electrode tab 142. The length L1 of the first step compensation unit 181 is not limited, but may be within a range between the upper end and the lower end of the insulating tape 170. A width W2 of the second step compensation unit 182 may be approximately the width of the negative electrode tab 142 , and a length L2 of the second step compensation unit 182 may be within a range between a lower end of the negative electrode tab 142 and a lower end of the insulating tape 170 .

[0074] The step compensation unit 180 compensates for the thickness of a relatively thin portion around the negative electrode tab 142 caused by the negative electrode tab 142, and the upper surface of the step compensation unit 180 may be aligned with the upper surface B of the insulating tape 170 corresponding to the negative electrode tab 142, but may be relatively lower or higher than the upper surface B of the insulating tape 170. For example, Fig. 9 As shown in , the thickness T2 of the step compensation unit 180 may be in the range of about 0.1×T1≤T2≤1.5×T1, where T1 is the thickness of the negative electrode tab 142.

[0075] When the thickness T2 of the step compensation unit 180 is too thick (exceeding about 150%) compared to the thickness T1 of the negative electrode tab 142, the battery capacity may be reduced, which may be disadvantageous, and the step compensation unit 180 may exert pressure on the negative electrode substrate. Therefore, considering the tolerance of the step compensation unit 180, the negative electrode tab 142 may be formed to reach about 150% of the thickness T1. In some embodiments, when the step compensation unit 180 is thinner than the negative electrode tab 142, there will be no problem, but in order to allow the effect of the step compensation unit 180 to be fully demonstrated, the thickness T2 of the step compensation unit 180 is at least about 10% of the thickness T1 of the negative electrode tab 142.

[0076] like Fig.11 As shown in, in the negative electrode plate 122, when the thickness Ta of the third layer M3 including the negative electrode substrate, the negative electrode active material coating portion 122a and the insulating tape 170 is different from the thickness Tb of the fourth layer M4 including the negative electrode substrate, the negative electrode terminal tab 142 and the insulating tape 170, the step compensation unit 180 can be formed to have a thickness that gradually decreases or increases in a direction from the third layer M3 to the fourth layer M4, so that its cross-section can be formed to be inclined.

[0077] For example, when the thickness Ta of the third layer M3 is greater than the thickness Tb of the fourth layer M4, the step compensation unit 180 may be formed to have a thickness gradually decreasing in a direction from the third layer M3 to the fourth layer M4. Fig.11 In the step compensation unit 180 shown in FIG. 1 , a thickness T21 of a left portion thereof is greater than a thickness T22 of a right portion thereof.

[0078] On the contrary, when the thickness Ta of the third layer M3 is less than the thickness Tb of the fourth layer M4, the step compensation unit 180 may be formed to have a thickness gradually increasing in a direction from the third layer M3 to the fourth layer M4. In such an embodiment, the thickness T21 of the left portion of the step compensation unit 180 may be less than the thickness T22 of the right portion thereof.

[0079] In some embodiments, for example, Fig.12As shown in , the insulating tape 170 may be additionally formed in the same shape on the lower surface of the second electrode non-coating portion 122b opposite to the upper surface to which the negative electrode tab 142 is connected at a position corresponding to the upper surface. The step compensation unit 180 may also be formed in the same shape on the lower surface of the insulating tape 170 formed on the lower surface of the second electrode non-coating portion 122b at a position corresponding to its position on the upper surface of the insulating tape 170. The total thickness (T2+T3) of the step compensation unit 180 may be in the range of about 0.1×T1≤T2+T3≤1.5×T1. Here, T1 is the thickness of the negative electrode tab 142, T2 is the thickness of the step compensation unit 180 formed on the upper surface of the second electrode non-coating portion 122b, and T3 is the thickness of the step compensation unit 180 formed on the lower surface of the second electrode non-coating portion 122b.

[0080] As described above, in a secondary battery according to an embodiment of the present disclosure, the pressure applied to the electrode tab is compensated by attaching a tape having the same thickness as the electrode tab to the uncoated portion of the electrode (e.g., the portion of the electrode film not coated with active material) around the electrode tab, thereby reducing or minimizing cracks or ruptures that may occur along the boundary area of ​​the existing electrode tab.

[0081] The foregoing embodiments are only some embodiments for carrying out the present disclosure and are not limited to these embodiments. Therefore, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A secondary battery, comprising: A first electrode plate including a first substrate having a first active material coating portion coated with a first active material and a first electrode non-coating portion not coated with the first active material; A second electrode plate including a second substrate having a second active material coating portion coated with a second active material and a second electrode non-coating portion not coated with the second active material; a separator, between the first electrode plate and the second electrode plate; an electrode tab connected to one of the first electrode uncoated portion and the second electrode uncoated portion; an insulating tape on the first electrode uncoated portion or the second electrode uncoated portion and covering the electrode terminal tab; as well as A step compensation unit is formed on a region of the upper surface of the insulating tape except a region corresponding to the electrode tab.

2. The secondary battery according to claim 1, wherein The step compensation unit includes a first step compensation unit located on both ends of the insulation tape at the upper surface of the insulation tape.

3. The secondary battery according to claim 2, wherein: The step compensation unit further includes a second step compensation unit on a region of the insulating tape between the first step compensation units and not corresponding to the electrode tab.

4. The secondary battery according to claim 3, wherein The first step compensation units are connected to each other using the second step compensation units between the first step compensation units.

5. The secondary battery according to claim 1, wherein The step compensation unit has a width extending from one end of the electrode tab to one end of the insulating tape.

6. The secondary battery according to claim 5, wherein The insulating tape is on the upper surface of the first electrode plate to cover a portion of the first active material coating portion, the electrode terminal tab and the first electrode uncoated portion, or on the upper surface of the second electrode plate to cover a portion of the second active material coating portion, the electrode terminal tab and the second electrode uncoated portion.

7. The secondary battery according to claim 1, wherein A thickness T2 of the step compensation unit is in the range of 0.1×T1≤T2≤1.5×T1, where T1 is a thickness of the electrode tab.

8. The secondary battery according to claim 1, wherein: When a thickness of a first layer including the first substrate, the first active material coating portion, and the insulating tape is different from a thickness of a second layer including the first substrate, the electrode tab, and the insulating tape, the step compensation unit has a thickness that gradually decreases or increases in a direction from the first layer to the second layer; or In the second electrode plate, when the thickness of the third layer including the second substrate, the second active material coating portion and the insulating tape is different from the thickness of the fourth layer including the second substrate, the electrode terminal and the insulating tape, the step compensation unit has a thickness that gradually decreases or increases in a direction from the third layer to the fourth layer.

9. The secondary battery according to claim 1, wherein: The insulating tape is additionally arranged in the same shape on a lower surface of the first electrode uncoated portion or the second electrode uncoated portion opposite to the upper surface to which the electrode terminal tab is connected at a position corresponding to the upper surface; and The step compensation unit is additionally disposed in the same shape on the lower surface of the insulating tape disposed on the lower surface of the first electrode non-coating portion or the second electrode non-coating portion at a position corresponding to its position on the upper surface of the insulating tape.

10. The secondary battery according to claim 9, wherein The total thickness T2+T3 of the step compensation unit is in the range of 0.1×T1≤T2+T3≤1.5×T1, wherein T1 is the thickness of the electrode terminal, T2 is the thickness of the step compensation unit located on the upper surface of the first electrode uncoated portion or the second electrode uncoated portion, and T3 is the thickness of the step compensation unit located on the lower surface of the first electrode uncoated portion or the second electrode uncoated portion.

11. The secondary battery according to claim 1, wherein The step compensation unit includes an adhesive tape including a film and an adhesive layer on a lower surface of the film.

12. The secondary battery according to claim 11, wherein The film includes polyimide, polyethylene terephthalate, or polypropylene, and the adhesive layer includes an acrylic compound, a rubber compound, or a hydrocarbon resin compound.

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