Electrode assembly and rechargeable battery including the same

Abstract

Provided are an electrode assembly and a rechargeable battery including the same, the electrode assembly including: a positive electrode including a positive electrode current collector and a positive electrode active material layer on at least one side of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer on at least one side of the negative electrode current collector; and a separator between the positive electrode and the negative electrode, and the electrode assembly is formed by winding the positive electrode, the negative electrode, and the separator, in which, at an outermost portion of the electrode assembly, the positive electrode is terminated longer than the negative electrode, and the separator is terminated longer than the positive electrode.

Description

Technical Field

[0001] Aspects of some embodiments of the present disclosure are directed to an electrode assembly, a wound electrode assembly, and a rechargeable battery including the electrode assembly. Background Art

[0002] Unlike primary batteries, rechargeable batteries are batteries that are constructed to be repeatedly charged and discharged. Small-capacity rechargeable batteries are used in portable small electronic devices such as portable phones, laptop computers, and video cameras. Rechargeable batteries with large capacity and high density can be used as a power source for driving motors for hybrid vehicles and electric vehicles or for energy storage.

[0003] Rechargeable batteries can ideally exhibit high capacity and high power characteristics while being safe even in the same size, so the development of rechargeable battery technology is also focused thereon, but it cannot meet the needs of users.

[0004] The above information disclosed in this Background section is only for enhancement of background understanding and therefore the information discussed in this Background section does not necessarily constitute prior art. Summary of the invention

[0005] Aspects of some embodiments of the present disclosure include an electrode assembly that can improve safety and efficiency of a rechargeable battery and a rechargeable battery including the electrode assembly.

[0006] However, features according to the embodiments of the present disclosure are not limited to the above-mentioned problems, and other problems not mentioned may be clearly understood by those of ordinary skill in the art through the description of the invention described below.

[0007] The electrode assembly according to some embodiments of the present disclosure includes: a positive electrode, including a positive electrode current collector and a positive electrode active material layer on at least one side of the positive electrode current collector; a negative electrode, including a negative electrode current collector and a negative electrode active material layer on at least one side of the negative electrode current collector; a separator, between the positive electrode and the negative electrode, the electrode assembly is formed by winding the positive electrode, the negative electrode and the separator. At the outermost portion of the electrode assembly, the positive electrode is terminated to be longer than the negative electrode, and the separator is terminated to be longer than the positive electrode.

[0008] A rechargeable battery according to some embodiments includes the above-described electrode assembly and a case accommodating the electrode assembly therein.

[0009] According to some embodiments of the present disclosure, because the positive electrode is terminated to be longer than the negative electrode at the outermost part of the electrode assembly, and the separator is terminated to be longer than the positive electrode, short circuiting of the positive electrode and the negative electrode can be prevented or reduced by minimizing or improving the shrinkage of the separator and the positive electrode in a high temperature environment.

[0010] Furthermore, since the positive electrode on the outermost portion of the electrode assembly according to some embodiments is covered by a protective member to prevent or reduce exposure to the external environment, the electrode assembly may reduce the possibility of being damaged due to external impact.

[0011] In addition, in an electrode assembly according to some embodiments, when the positive electrode and the negative electrode are designed to have the same capacity compared to an electrode assembly of the related art that terminates by a circular area surrounding the electrode assembly, the energy density can be increased by reducing the thickness of the current collector of each positive and negative electrode and the thickness of the separator. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The drawings attached to this specification illustrate aspects of some embodiments of the present disclosure and, together with the detailed description of the invention described later, are used to further understand aspects of some embodiments of the present disclosure, and therefore the embodiments according to the present disclosure should not be interpreted as being limited to the contents described in these drawings.

[0013] Figure 1 is a schematic perspective view of an electrode assembly according to some embodiments.

[0014] Figure 2 It is taken along the II-II line. Figure 1 sectional view of .

[0015] Figure 3A A positive electrode tab is provided for describing an electrode assembly according to some embodiments.

[0016] Figure 3B A negative electrode tab is provided for describing an electrode assembly according to some embodiments.

[0017] Figure 4 is a cross-sectional view of an electrode assembly according to some embodiments.

[0018] Figure 5A and Figure 5B A positive electrode tab is provided for describing an electrode assembly according to some embodiments.

[0019] Figure 6 is a perspective view of a rechargeable battery according to some embodiments.

[0020] Figure 7 is a perspective view of a rechargeable battery according to some embodiments. DETAILED DESCRIPTION

[0021] Aspects of some embodiments of the present disclosure are described in more detail below with reference to the accompanying drawings. Prior to this, the terms or words used in this specification and the scope of the claims should not be interpreted as limited to their usual meanings or dictionary meanings, and they must be interpreted with meanings and concepts consistent with the technical ideas of the present disclosure based on the principle that the concepts of the terms can be appropriately defined by the inventor to explain the invention in the best possible way. Therefore, the embodiments described in this specification and the constructions shown in the figures are only examples of some embodiments of the present disclosure, and do not represent all of the technical ideas of the present disclosure, so it should be understood that there may be many equivalent changes and alternative changes according to some embodiments of the present disclosure.

[0022] In addition, when "includes", "comprising" and / or their variations are used in this specification, it indicates the existence of the mentioned shapes, quantities, steps, operations, components, elements and / or these groups, but does not exclude the existence or addition of one or more other shapes, quantities, steps, operations, components, elements and / or groups.

[0023] In addition, for a better understanding of the invention, the accompanying drawings may not be drawn to actual scale, but the sizes of some components may be exaggerated. In addition, the same reference numerals may be assigned to the same components in other embodiments.

[0024] The statement that two compared objects are "the same" means "substantially the same." Thus, substantially the same can include deviations that are considered low in the industry, such as deviations of less than 5%. In addition, uniformity of a parameter in a given area can mean uniformity from an average perspective.

[0025] Although the first, second, etc. are used to describe various construction elements, these components are of course not limited by these terms. These terms are only used to distinguish one component from another component, and unless specifically stated otherwise, the first component may also be the second component.

[0026] Throughout the specification, unless otherwise specified, each component may be singular or plural.

[0027] Placing any component on the "top (or bottom)" of a component or the "upper (or lower)" of a component not only means placing any component in contact with the top (or bottom) of the component, but also means that other structures may be placed between the component and any component on the top (or bottom) of the component.

[0028] In addition, when a component is described as being "on," "connected to," or "coupled to" another component, the components may be directly connected or coupled to each other, but it should be understood that other components may be "placed between" the components, or that the components may be "connected," "coupled," or "accessed" through other components.

[0029] As used in this specification, the term "and / or" includes any 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" refers to "one or more embodiments of the present disclosure."

[0030] Expressions such as “one or more” and “one or more of” preceding a list of elements modify the entire list of elements and do not modify the individual elements of the list.

[0031] Throughout the specification, "A and / or B" means A, B, or A and B, unless specifically stated otherwise, and "C to D" means higher than C and lower than D, unless specifically stated otherwise.

[0032] When using syntax such as "at least one selected from A, B or C", "at least one selected from the group of A, B and C", and "at least one selected from A, B and C" to detail a list of elements A, B and C, the syntax may refer to any and all suitable combinations.

[0033] The term "use" may be considered synonymous with the term "utilize."

[0034] As used in this specification, "substantially," "approximately," and similar terms are used as terms of approximation rather than terms of degree, and are provided to take into account the inherent variations in measurements or calculations that those of ordinary skill in the art will recognize.

[0035] Although the terms first, second, third, etc. may be used in this specification 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. Such terms are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Therefore, without departing from the teachings of the exemplary embodiments, the first element, first component, first region, first layer or first part described below may be named as the second element, second component, second region, second layer or second part.

[0036] As shown in the figures, in order to describe the relationship between one element or feature and another element or feature, spatial relative terms such as "under", "below", "down", "above", "on", etc. may be used to facilitate the description in this specification. In addition to covering the directions depicted in the drawings, spatial relative positions will be understood to also cover different directions of the device in use or operation. For example, when the device in the drawings is turned over, an element described as "under" or "bottom" is understood to be "on" or "above" another element. Therefore, the term "below" can cover both upward and downward directions.

[0037] The terms used in this specification are intended to describe the embodiments of the present disclosure but are not intended to limit the present disclosure.

[0038] In example embodiments of prismatic rechargeable batteries and pouch-type rechargeable batteries according to some embodiments of the present disclosure, one of the prismatic rechargeable batteries and the pouch-type rechargeable batteries is selected, and the selected battery is described as having a general structure, and under the circumstances of commonly applied technology, the general structure of the prismatic rechargeable battery and the pouch-type rechargeable battery will be disclosed.

[0039] An electrode assembly according to some embodiments of the present disclosure is provided. The electrode assembly according to some embodiments includes: a positive electrode including a positive electrode current collector and a positive electrode active material layer on at least one side of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer on at least one side of the negative electrode current collector; a separator between the positive electrode and the negative electrode, and the electrode assembly is formed by winding the positive electrode, the negative electrode and the separator. Here, at the outermost portion of the electrode assembly, the positive electrode is terminated to be longer than the negative electrode, and the separator is terminated to be longer than the positive electrode.

[0040] According to some embodiments, the electrode assembly includes a circular region and a flat region, the separator may be terminated by covering the circular region of the electrode assembly, and the positive electrode and the negative electrode may be terminated in the flat region of the electrode assembly.

[0041] According to some embodiments, when the positive electrode is terminated to be longer than the negative electrode, the positive electrode current collector of the positive electrode may be terminated to be longer than the negative electrode.

[0042] According to some embodiments, the positive electrode active material layer is on one side of the positive electrode current collector, and an adhesive tape for attaching a separator may be disposed on the other side of the positive electrode current collector facing the positive electrode active material layer.

[0043] According to some embodiments, the membrane may terminate at the end of the adhesive tape.

[0044] According to some embodiments, a ceramic functional layer covering the positive electrode active material layer may be on the other side of the positive electrode current collector, the ceramic functional layer corresponding to from the starting end of the adhesive tape to the end of the positive electrode current collector.

[0045] According to some embodiments, a sealing tape may surround the separator at the outermost portion of the electrode assembly while being attached to the ceramic functional layer.

[0046] According to some embodiments, the positive electrode may be terminated to be longer than the negative electrode in the range of 1 millimeter (mm) to 5 mm, for example 3 mm.

[0047] According to some embodiments, the electrode assembly further includes a positive electrode tab connected to the positive electrode current collector and a negative electrode tab connected to the negative electrode current collector. Here, the positive electrode tab is connected to an uncoated region disposed at an end of the positive electrode current collector, and the negative electrode tab may be connected to an uncoated region disposed at an end of the negative electrode current collector. On the other hand, the positive electrode tab may be connected to an uncoated region disposed in an area other than the end of the positive electrode current collector, and the negative electrode tab may be connected to an uncoated region disposed at an end of the negative electrode current collector.

[0048] According to some embodiments, an end of the separator may not overlap the positive electrode tab.

[0049] A rechargeable battery according to some embodiments of the present disclosure includes the above-described electrode assembly and a case accommodating the electrode assembly therein. The rechargeable battery may be configured in a prismatic shape or a pouch type.

[0050] Figure 1 is a schematic perspective view of an electrode assembly according to some embodiments of the present disclosure, Figure 2 It is taken along the II-II line. Figure 1 sectional view of . Figure 3A A positive electrode tab of an electrode assembly according to some embodiments is shown. Figure 3B A negative electrode tab of an electrode assembly according to some embodiments is shown.

[0051] The electrode assembly in the present disclosure is an electrode assembly for a rechargeable battery, for example, it may be an electrode assembly for a rechargeable lithium battery, but the electrode assembly according to an embodiment of the present disclosure is not necessarily limited thereto.

[0052] like Figure 1 and Figure 2As shown in the figure, the electrode assembly 10 is formed by a jelly-roll shaped electrode assembly formed by winding a positive electrode 100, a negative electrode 200 and a separator 300 located between the positive electrode 100 and the negative electrode 200 so that the starting ends of the positive electrode 100, the negative electrode 200 and the separator 300 are located at the center of the electrode assembly 10, and the ends of the positive electrode 100, the negative electrode 200 and the separator 300 are located at the outermost part of the electrode assembly 10.

[0053] That is, the electrode assembly 10 is formed by winding the positive electrode 100, the negative electrode 200 and the separator 300 formed in the shape of a thin strip several times around the winding axis O. The final wound electrode assembly 10 can be constructed to include a substantially flat flat area 10a and a rounded region 10b curved in a circular shape. The circular regions 10b are arranged relative to each other so that the flat region 10a is arranged therebetween. The radius of curvature of the outermost circular region 10b of the electrode assembly 10 may vary depending on the number of windings of the positive electrode 100, the negative electrode 200 and the separator 300. It should be noted here that the "circular region" means that the outline of the region has the shape of a portion of a circle, rather than the outline shape of a whole circle.

[0054] The positive electrode 100 includes a positive electrode collector 100 a formed of a metal foil such as aluminum or an aluminum alloy and a positive electrode active material layer 100 b including a positive electrode active material such as a transition metal oxide applied to at least one side of the positive electrode collector 100 a .

[0055] like Figure 2 As shown in , with reference to the finally wound electrode assembly 10, the positive electrode active material layer 100b is mainly located at both sides of the positive electrode collector 100a, but on the other hand, in the positive electrode collector 100a located in the circular region 10b and the flat region 10a corresponding to the outermost portion of the electrode assembly 10, the positive electrode active material layer 100b is located only on one side facing the central portion of the electrode assembly 10 ( Figure 2 inside of the ).

[0056] Meanwhile, the positive electrode active material layer 100b is not located at the end portion of the positive electrode current collector 100a, which is located at the flat region 10a as the outermost portion of the electrode assembly 10. That is, the end portion is formed as a positive electrode uncoated region 1000a in which the positive electrode active material is not coated. The positive electrode tab 100c is attached to the positive electrode uncoated region 1000a.

[0057] exist Figure 3A In some embodiments, the positive electrode 100 has a strip shape before being wound. Figure 3AAs shown in , the positive electrode tab 100c is attached to the positive electrode uncoated region 1000a provided at one end of the positive electrode 100 while protruding from the positive electrode uncoated region 1000a provided at one end (i.e., the terminal portion in the wound state) of the positive electrode 100. The positive electrode tab 100c may be connected to the positive electrode uncoated region 1000a by welding a separate component formed of the same material as that of the positive electrode current collector 100a. On the other hand, in some embodiments, the positive electrode tab 100c may be formed as a part of the positive electrode current collector 100a when the positive electrode current collector 100a is manufactured.

[0058] like Figure 2 As shown in , the adhesive tape 400a covering the positive electrode tab 100c and simultaneously attaching the separator 300 thereto may be located in the uncoated region 1000a of the positive electrode current collector 100a to which the positive electrode tab 100c is attached. Here, the end of the adhesive tape 400a may be arranged or formed to match the end portion of the positive electrode current collector 100a, or to cover the end portion of the positive electrode current collector 100a.

[0059] The negative electrode 200 includes a negative electrode collector 200a formed of a metal foil such as copper, copper alloy, nickel or nickel alloy and a negative electrode active material layer 200b including a negative electrode active material such as graphite or carbon applied to at least one side of the negative electrode collector 200a.

[0060] like Figure 2 As shown in FIG. 1 , with reference to the finally wound electrode assembly 10, the negative electrode active material layer 200 b is mainly located at both sides of the negative electrode current collector 200 a, but on the other hand, the negative electrode current collector 200 a located in the flat region 10 a and the circular region 10 b corresponding to the central portion of the electrode assembly 10, the negative electrode active material layer 200 b is located on one side of the negative electrode current collector 200 a facing the outer edge of the electrode assembly 10 ( Figure 2 outside of the center).

[0061] In addition, the negative electrode active material layer 200b is not located at the starting end of the negative electrode current collector 200a, which is located at the flat area 10a at the center of the electrode assembly 10. That is, the starting end is formed by the negative electrode uncoated area 2000a in which the negative electrode active material is not applied. The negative electrode tab 200c is attached to the negative electrode uncoated area 2000a.

[0062] exist Figure 3B In some embodiments, the negative electrode 200 has a strip shape before winding. Figure 3BAs shown in , the negative electrode tab 200c is attached to the negative electrode uncoated region 2000a provided at one end of the negative electrode 200 while protruding from the negative electrode uncoated region 2000a provided at one end (i.e., the starting end in the wound state) of the negative electrode 200. The negative electrode tab 200c may also be connected to the negative electrode uncoated region 2000a by welding a separate component formed of the same material as that of the negative electrode current collector 200a, and in some embodiments, the negative electrode tab 200c may be formed as a part of the negative electrode current collector 200a when the negative electrode current collector 200a is manufactured.

[0063] like Figure 2 As shown in FIG. 4 , the adhesive tape 400 b is attached to the uncoated region 2000 c of the negative electrode current collector 200 a while covering the negative electrode tab 200 c .

[0064] The positive electrode 100, the negative electrode 200, and the separator 300 located between the positive electrode 100 and the negative electrode 200 are wound a plurality of times (eg, a set or predetermined number of times), and the positive electrode 100 is wound longer than the negative electrode 200. That is, referring to Figure 2 , the terminal portion of the positive electrode current collector 100a of the positive electrode 100 extends beyond the terminal portion of the negative electrode 200, and thus ends while covering the end of the negative electrode 200. Here, the distance between the terminal end of the positive electrode current collector 100a and the terminal end of the negative electrode 200 may be maintained between 1 mm and 5 mm, and according to some embodiments, the distance is maintained at 3 mm.

[0065] In addition, the positive electrode 100 and the negative electrode 200 may both terminate in the flat region 10 a of the electrode assembly 10 , and according to some embodiments, they may both terminate in a circular region or in one region selected from a circular region or a flat region.

[0066] Meanwhile, the separator 300 is terminated to be longer than the positive electrode 100. According to some embodiments, the separator 300 extends to a circular region (ie, 10b, Figure 2 ), and thus ends in a form covering the positive electrode 100, the negative electrode 200, and the separator 300 located in the circular area 10b. Here, the separator 300 may be fixed by an adhesive tape 400c disposed on the other side of the positive electrode current collector 100a (i.e., the side where the positive electrode active material layer 100b is not disposed). The adhesive tape 400c may extend not only to the circular area 10b of the electrode assembly 10, but also to the flat area 10a of the electrode assembly 10 where each end portion of the positive electrode 100 and the negative electrode 200 is positioned.

[0067] In addition, in the positive electrode 100 according to some embodiments, the ceramic functional layer 500 that can improve the heat insulation property, the insulation property, or the strength property can be located on the side of the positive electrode current collector 100a where the positive electrode active material layer 100b is not disposed. The ceramic functional layer 500 is located on one side of the positive electrode current collector 100a in a form that can completely cover the positive electrode 100 at the outermost portion of the electrode assembly 10. Therefore, the positive electrode current collector 100a is not exposed to the outside of the electrode assembly 10.

[0068] The sealing tape 600 is disposed on the outermost portion of the electrode assembly 10 to finally terminate the positive electrode 100, the negative electrode 200, and the separator 300. The sealing tape 600 is disposed along one direction (ie, Figure 2 The electrode assembly 10 is provided with a plurality of electrodes 100 and 200, and each of the end portions of the positive electrode 100 and the negative electrode 200 is surrounded by the plurality of electrodes 100 and 200, and one end of the electrode assembly 10 is fixed to the outer surface of the ceramic functional layer 500 located in the flat region 10a of the electrode assembly 10, and the electrode assembly 10 is provided with a plurality of electrodes 100 and 200 in the same direction. Figure 2 The electrode assembly 10 is passed through the circular region 10 b of the electrode assembly 10 and covers the end portion of the separator 300 , while the other end of the electrode assembly 10 is fixed to the other outer surface of the ceramic functional layer 500 located in the flat region 10 a of the electrode assembly 10 .

[0069] In such an electrode assembly 10, the positive electrode 100 is terminated to be longer than the negative electrode 200 at the outermost portion, and the separator 300 is terminated to be longer than the positive electrode 100. In addition, at the outermost portion of the electrode assembly 10, the positive electrode 100 (i.e., the positive electrode current collector 100a) is covered by the ceramic functional layer 500, the separator 300, the sealing tape 600, etc., thereby preventing or reducing exposure of the outside of the electrode assembly 10.

[0070] According to some embodiments, since the positive electrode is terminated to be longer than the negative electrode at the outermost portion of the electrode assembly, and the separator is terminated to be longer than the positive electrode, when a rechargeable battery including the electrode assembly is subjected to a high temperature environment (e.g., thermal runaway), short circuiting of the positive electrode and the negative electrode can be prevented or reduced by minimizing or reducing shrinkage of the separator and the positive electrode.

[0071] Furthermore, since the outermost positive electrode of the electrode assembly according to some embodiments is covered by a protective member (eg, a ceramic functional layer) to prevent or reduce exposure to the external environment, the electrode assembly may reduce the possibility of damage due to external impact.

[0072] In addition, in an electrode assembly according to some embodiments, when the positive electrode and the negative electrode are designed to have the same capacity compared to an electrode assembly of the related art that terminates by a circular area surrounding the electrode assembly, the energy density can be increased by reducing the thickness of the current collector of each positive and negative electrode and the thickness of the separator.

[0073] Figure 4 is a cross-sectional view of an electrode assembly according to some embodiments. Except for the position of the positive electrode tab, the electrode assembly 20 according to some embodiments is the same as the above-described electrode assembly 10 described above. Therefore, for ease of description, the same name may be assigned to the same symbol, and only the positive electrode tab will be described.

[0074] like Figure 4 As shown in , in the electrode assembly 20 according to some embodiments, the positive electrode tab 100c of the positive electrode 100 is attached to an uncoated area disposed at a random position between portions of the positive electrode collector 100a other than the end portions, that is, between the opposite ends of the positive electrode collector 100a.

[0075] Figure 5A and Figure 5B 1 and 2 are front and rear views showing a positive electrode 100 in an unwound state according to some embodiments, and as shown in these figures, a positive electrode tab 100c is attached to an uncoated region 1000a disposed at a substantially central portion of a positive electrode collector 100a.

[0076] Therefore, if Figure 4 As shown in FIG. 1 , in a state in which the positive electrode 100 is wound, the positive electrode tab 100 c is located at the inner side of the electrode assembly 20 at the flat region 10 a of the electrode assembly 20 .

[0077] According to some embodiments, when the sealing tape 600 is terminated by being attached to the ceramic functional layer 500, it may be attached to the ceramic functional layer 500 in a form not overlapping the positive electrode tab 100c. Figure 4 , the sealing tape 600 is arranged to be attached to the ceramic functional layer 500 without reaching the left end of the positive electrode tab 100 c .

[0078] Figure 6 is a perspective view of a rechargeable battery including an electrode assembly according to some embodiments. Figure 6 In the rechargeable battery 70 of the present invention, the case 700 accommodating the electrode assembly is formed of a prismatic case having rigidity (eg, including metal).

[0079] Figure 7 is a perspective view of another rechargeable battery including an electrode assembly according to some embodiments. Figure 7 In the rechargeable battery 80 of the present invention, the case 800 including the above-mentioned electrode assembly is formed of a pouch-type case (eg, containing resin) having flexibility.

[0080] Table 1 below shows the results of evaluating the stability characteristics and efficiency characteristics of the electrode assembly of the first embodiment and the electrode assembly of the second embodiment and the electrode assembly according to the comparative example. The electrode assembly of the comparative example is the same as the electrode assembly according to some embodiments, except that the positive electrode, the negative electrode and the separator are respectively terminated in the order of the negative electrode, the separator and the positive electrode in length.

[0081] Table 1

[0082] The penetration evaluation was performed after pausing the battery cell including each electrode assembly that had been charged for a period of time for a period of time (e.g., a set or predetermined period of time) and penetrating the center of the battery cell with a metal needle having a diameter of 3 mm at a random speed (e.g., 50 mm / sec). As a result of the evaluation, it was confirmed that none of the battery cells of the first and second embodiments caught fire after 20 tests, and the battery cell of the comparative example caught fire after 20 tests.

[0083] By placing a round rod (e.g. 15.8±0.1mm) was positioned at the center of the battery cell including the electrode assembly of each example that had been charged and aged for a period of time, and a weight (e.g., 9.1±0.46kg) was freely dropped on the round bar at a certain height (e.g., 610±25mm) to perform collision evaluation. As a result of the evaluation, it was confirmed that the battery cells of the first and second embodiments were good up to 16 and 18 tests, respectively, after 20 tests, and the battery cells of the comparative example were good only up to 4 tests after 20 tests.

[0084] The heat exposure evaluation was performed by keeping the electrode assembly including each fully charged battery cell at a certain temperature for 1 hour to evaluate the condition of the battery cell. As a result of the evaluation, it was confirmed that none of the twenty battery cells of the first and second embodiments caught fire at a temperature below 138°C, and each of the twenty battery cells of the comparative example caught fire at a temperature below 133°C.

[0085] It was confirmed through energy density evaluation that the battery cells including the electrode assemblies of the first and second embodiments maintained high capacity compared with the comparative example.

[0086] While aspects of some embodiments of the present disclosure have been described in connection with what are presently considered to be practical embodiments, it will be understood that the present disclosure is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims and functional equivalents of the appended claims to be included therein.

[0087] Description of some reference symbols 10, 20: Electrode assembly 100: Positive electrode 100a: Positive electrode current collector 100b: Positive electrode active material layer 100c: Positive electrode terminal 200: Negative electrode 200a: Negative electrode current collector 200b: Negative electrode active material layer 200c: Negative electrode terminal 300: Diaphragm.

Claims

1. An electrode assembly, comprising: a positive electrode comprising a positive electrode current collector and a positive electrode active material layer on at least one side of the positive electrode current collector; a negative electrode including a negative electrode current collector and a negative electrode active material layer on at least one side of the negative electrode current collector; as well as a separator between the positive electrode and the negative electrode, and The electrode assembly is formed by winding the positive electrode, the negative electrode, and the separator, wherein, at the outermost portion of the electrode assembly, the positive electrode is terminated to be longer than the negative electrode, and the separator is terminated to be longer than the positive electrode.

2. The electrode assembly according to claim 1, wherein: The electrode assembly includes a circular region and a flat region, and The separator terminates by covering the circular region of the electrode assembly.

3. The electrode assembly according to claim 1, wherein: The electrode assembly includes a circular region and a flat region, and The positive electrode and the negative electrode terminate in the planar region of the electrode assembly.

4. The electrode assembly according to claim 1, wherein: The positive electrode current collector is terminated to be longer than the negative electrode.

5. The electrode assembly according to claim 2, wherein: The positive electrode active material layer is at a first side of the positive electrode current collector, and an adhesive tape for attaching the separator is at a second side of the positive electrode current collector opposite to the positive electrode active material layer.

6. The electrode assembly according to claim 5, wherein: The membrane terminates at a terminal end of the adhesive tape.

7. The electrode assembly according to claim 5, wherein: The ceramic functional layer covering the positive electrode active material layer corresponds to the starting end portion of the adhesive tape to the terminal end portion of the positive electrode current collector at the second side of the positive electrode current collector. 8 . The electrode assembly according to claim 7 , further comprising a sealing tape surrounding the separator while being attached to the ceramic functional layer.

9. The electrode assembly according to claim 1, wherein: The positive electrode is terminated to be in the range of 1 mm to 5 mm longer than the negative electrode.

10. The electrode assembly according to claim 9, wherein: The positive electrode was terminated 3 mm longer than the negative electrode.

11. The electrode assembly according to claim 1, wherein: The electrode assembly further comprises: a positive electrode tab connected to the positive electrode current collector; and a negative electrode tab connected to the negative electrode current collector, The positive electrode tab is connected to an uncoated region disposed at an end of the positive electrode collector, and the negative electrode tab is connected to an uncoated region disposed at an end of the negative electrode collector.

12. The electrode assembly according to claim 1, wherein: The electrode assembly comprises: a positive electrode tab connected to the positive electrode current collector; and a negative electrode tab connected to the negative electrode current collector, The positive electrode tab is connected to an uncoated region disposed in a region other than an end portion of the positive electrode collector, and the negative electrode tab is connected to an uncoated region disposed at an end portion of the negative electrode collector.

13. The electrode assembly according to claim 12, wherein: A terminal end portion of the separator does not overlap the positive electrode tab.

14. A rechargeable battery, comprising: The electrode assembly according to claim 1; as well as A casing is provided in which the electrode assembly is accommodated.

15. The rechargeable battery according to claim 14, wherein: The rechargeable battery has a prismatic shape.

16. The rechargeable battery according to claim 14, wherein: The rechargeable battery is a pouch type rechargeable battery.

Images