Electrode assembly and secondary battery including the same

Abstract

The invention provides an electrode assembly and a secondary battery including the same. The electrode assembly includes: a first electrode including a first substrate, a first mixture portion including an active material and coated on one surface of the first substrate, a first non-coated portion on the one surface of the first substrate, the first non-coated portion of the first substrate being exposed, and a first insulating layer on the first non-coated portion; a second electrode including a second substrate, a second mixture portion including an active material and coated on one surface of the second substrate, a second non-coated portion on the one surface of the second substrate, and a second insulating layer on the second non-coated portion, the second non-coated portion of the second substrate being exposed; and a separator between the first electrode and the second electrode.

Description

Technical Field

[0001] This disclosure relates to electrode assemblies and secondary batteries including the electrode assemblies. Background Technology

[0002] Unlike primary batteries, which are not designed for (re)charging, secondary (or rechargeable) batteries are designed to discharge and be recharged. Low-capacity secondary batteries are used in portable small electronic devices such as smartphones, feature phones, laptops, digital cameras, and camcorders, while high-capacity secondary batteries are widely used as power sources for motors in hybrid and electric vehicles, as well as for storing electricity (e.g., household and / or utility-scale power storage). Secondary batteries typically consist of an electrode assembly containing positive and negative electrodes, a housing, and electrode terminals connected to the electrode assembly.

[0003] The information disclosed in this background section is intended to enhance the understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0004] The embodiment includes an electrode assembly comprising: a first electrode including a first substrate, a first mixture portion including an active material coated on one surface of the first substrate, a first uncoated portion on one surface of the first substrate, and a first insulating layer on the first uncoated portion, the first uncoated portion of the first substrate being exposed; a second electrode including a second substrate, a second mixture portion including an active material coated on one surface of the second substrate, a second uncoated portion on one surface of the second substrate, and a second insulating layer on the second uncoated portion, the second uncoated portion of the second substrate being exposed; and a diaphragm between the first electrode and the second electrode.

[0005] The end of the first mixture portion may protrude beyond the end of the second mixture portion.

[0006] The first insulating layer may be coated on one surface of the first substrate, and the first insulating layer has a thickness in the range of 95% to 105% of the thickness of the first mixture portion.

[0007] The end of the diaphragm may protrude beyond the end of the first insulating layer.

[0008] One end of the first insulating layer can contact one end of the first mixture portion.

[0009] The width of the first insulating layer can be in the range of 10% to 75% of the width of the first uncoated portion.

[0010] The first insulating layer and the first mixture portion can be spaced apart from each other by a predetermined separation distance.

[0011] The sum of the predetermined separation distance and the width of the first insulating layer can be equal to or less than 75% of the width of the first uncoated portion.

[0012] The first insulating layer may cover a portion of the first mixture.

[0013] The width of the area in the first insulating layer covering a portion of the first mixture portion in the first direction may be the same as the width between the most convex portion of the first mixture portion in the opposite direction and the most convex portion of the second mixture portion in the opposite direction.

[0014] The diaphragm and the second electrode can be on top of the area where the first insulating layer covers the first mixture portion.

[0015] The embodiment includes a secondary battery comprising: an electrode assembly comprising stacked cell units, each cell unit comprising a first electrode, a separator, and a second electrode; a housing housing the electrode assembly; and an electrolyte within the housing, wherein the first electrode comprises a first substrate, a first mixture portion comprising active material coated on one surface of the first substrate, a first uncoated portion on one surface of the first substrate, and a first insulating layer disposed on the first uncoated portion, the first uncoated portion of the first substrate being exposed; wherein the second electrode comprises a second substrate, a second mixture portion comprising active material coated on one surface of the second substrate, a second uncoated portion on one surface of the second substrate, and a second insulating layer disposed on the second uncoated portion, the second uncoated portion of the second substrate being exposed; and wherein the separator is located between the first electrode and the second electrode.

[0016] The end of the first mixture portion may protrude beyond the end of the second mixture portion.

[0017] The first insulating layer may be coated on one surface of the first substrate, and the first insulating layer has a thickness in the range of 95% to 105% of the thickness of the first mixture portion.

[0018] The end of the diaphragm may protrude beyond the end of the first insulating layer.

[0019] One end of the first insulating layer can contact one end of the first mixture portion.

[0020] The width of the first insulating layer can be in the range of 10% to 75% of the width of the first uncoated portion.

[0021] The first insulating layer and the first mixture portion can be spaced apart from each other by a predetermined separation distance.

[0022] The first insulating layer may cover a portion of the first mixture.

[0023] The difference between the thickness of the edge portion of the first electrode and the thickness of the center portion of the first electrode can be equal to or less than a predetermined threshold difference.

[0024] These and other aspects and features of this disclosure will be described in or will become apparent from the following description of embodiments of this disclosure.

[0025] However, the aspects and features of this disclosure are not limited to those described above, and those skilled in the art will clearly understand from the detailed description below that other aspects and features not mentioned will be apparent. Attached Figure Description

[0026] The following accompanying drawings illustrate embodiments of the present disclosure, and together with the detailed description of the present disclosure, aspects and features of the present disclosure are further described. Therefore, the present disclosure should not be construed as limited to the drawings:

[0027] Figure 1 This is a schematic diagram of a secondary battery according to an embodiment of the present disclosure;

[0028] Figure 2 This is a cross-sectional view of a secondary battery according to an embodiment of the present disclosure;

[0029] Figure 3 An example of a first electrode according to an embodiment of the present disclosure is shown;

[0030] Figure 4A Another example of a first electrode according to an embodiment of the present disclosure is shown;

[0031] Figure 4B Another example of a first electrode according to an embodiment of the present disclosure is shown;

[0032] Figure 5A Another example of a first electrode according to an embodiment of the present disclosure is shown;

[0033] Figure 5B Another example of a first electrode according to an embodiment of the present disclosure is shown;

[0034] Figure 6A An additional example of a first electrode according to an embodiment of the present disclosure is shown;

[0035] Figure 6B An example of an electrode assembly according to an embodiment of the present disclosure is shown; and

[0036] Figure 7 This is a view comparing the difference in the presence or absence of an edge-side sliding region in electrodes of the prior art and electrodes of the present disclosure embodiments. Detailed Implementation

[0037] Example embodiments have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, as will be apparent to those skilled in the art at the time of filing this application, unless otherwise specifically indicated, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of this disclosure as set forth in the following claims.

[0038] In the following, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims should not be construed as limited to their ordinary or dictionary meanings, and should be interpreted in a way consistent with the technical spirit of the present disclosure, based on the principle that the inventor can be his / her own lexicographer to appropriately define the concepts of the terms so as to best interpret his / her invention.

[0039] The embodiments described in this specification and the configurations shown in the accompanying drawings are merely some embodiments of this disclosure and do not represent all technical ideas, aspects, and features of this disclosure. Therefore, it should be understood that various equivalents and modifications may exist to replace or modify the embodiments described herein at the time of filing this application.

[0040] It should be understood that when a component or layer is described as being "on," "connected to," or "bonded to" another component or layer, it can be directly on, directly connected to, or directly bonded to the other component or layer, or one or more intermediate components or layers may be present. When a component or layer is described as being "directly on," "directly connected to," or "directly bonded to" another component or layer, no intermediate components or layers are present. For example, when a first component is described as being "bonded" or "connected" to a second component, the first component can be directly bonded to or connected to the second component, or the first component can be indirectly bonded to or connected to the second component via one or more intermediate components.

[0041] In the accompanying drawings, the dimensions of various elements, layers, etc., may be exaggerated for clarity. The same reference numerals denote the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated listed items. Furthermore, when describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” Expressions such as “at least one of…” and “any one of…” modify the entire column of elements, not individual elements within that column, when following a column of elements. When a column of elements A, B, and C is specified using phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one selected from the group consisting of A, B, and C,” or “at least one selected from A, B, and C,” the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the terms “use,” “using…,” and “being used” may be considered synonymous with the terms “utilize,” “using…,” and “being exploited,” respectively. As used herein, the terms “substantially,” “about,” and similar terms are used as approximations rather than terms of degree, intended to describe the inherent biases of measurements or calculations that would be recognized by one of ordinary skill in the art.

[0042] It will be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, the first element, component, region, layer, or portion discussed below may be referred to as a second element, component, region, layer, or portion without departing from the teachings of the exemplary embodiments.

[0043] For ease of description, spatial relation terms such as “below,” “under,” “down,” “above,” and “above” are used herein to describe the relationship between one element or feature and another element or feature as shown in the figure. It will be understood that, in addition to the orientation depicted in the figure, spatial relation terms are also intended to cover different orientations of the device in use or operation. For example, if the device in the figure is flipped, the element described as “below” or “under” other elements or features will be oriented “above” or “above” other elements or features. Therefore, the term “below” can cover both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatial relation descriptors used herein should be interpreted accordingly.

[0044] The terminology used herein is for describing embodiments of the present disclosure and is not intended to limit the disclosure. As used herein, the singular form “a” is also intended to include the plural form unless the context clearly indicates otherwise. It will be further understood that the terms “comprising,” “including,” “including,” and / or “containing” as used in this specification indicate 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.

[0045] Furthermore, any numerical range disclosed and / or described herein is intended to include all subranges containing the same numerical precision within said range. For example, the range “1.0 to 10.0” is intended to include all subranges between (and including) said minimum value 1.0 and said maximum value 10.0, i.e., all subranges having a minimum value equal to or greater than 1.0 and a maximum value equal to or less than 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit described herein is intended to include all lower numerical limits contained therein, and any minimum numerical limit described in this specification is intended to include all higher numerical limits contained therein. Therefore, the applicant reserves the right to amend this specification (including the claims) to expressly describe any subranges contained within the range expressly described herein.

[0046] Referring to two compared elements, features, etc., as “identical” can mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with deviations considered low in the art, such as 5% or less. Additionally, when a parameter is said to be uniform in a given region, it can mean that it is uniform in terms of the mean.

[0047] Throughout this specification, unless otherwise stated, each element may be singular or plural.

[0048] The phrase "any element arranged above (or below)" or "above (or below)" another element can mean that the arbitrary element can be positioned to contact the upper (or lower) surface of the element, and that the other element can be inserted between the element and the arbitrary element disposed on (or below) the element.

[0049] Additionally, it will be understood that when components are referred to as “linked,” “joined,” or “connected” to another component, these components can be directly “linked,” “joined,” or “connected” to each other, or additional components can be “inserted” between these components.

[0050] Throughout this specification, unless otherwise stated, when “A and / or B” is used, it means A, B, or A and B. That is, “and / or” includes any or all combinations of the listed items. When “C to D” is used, unless otherwise stated, it means C or greater and D or less.

[0051] Figure 1 This is a schematic diagram illustrating a secondary battery according to an embodiment of the present disclosure.

[0052] Reference Figure 1 The secondary battery 100 may include an electrode assembly 10 and a housing 20 that accommodates the electrode assembly 10. Figure 1 In the lower left corner, for ease of understanding, a first direction (Y direction) as an imaginary direction, a second direction (Z direction) intersecting the first direction, and a third direction (X direction) intersecting each of the first (Y direction) and second (Z direction) directions are shown. Furthermore, according to... Figure 1 The diagram shows a line Q', which extends from the first electrode tab 14 of the secondary battery 100 to the outside of the housing 20, and the unbent portion Q intersects the secondary battery 100 along a first direction (Y direction) at a predetermined distance. According to an embodiment, from... Figure 1 The unbent portion Q of the first electrode tab 14 intersects a line Q' at a predetermined distance along the first direction (Y direction). This line may be a virtually defined line in the accompanying drawings for ease of understanding, and the unbent portion Q of the first electrode tab 14 may also be a virtually defined portion in the accompanying drawings for ease of understanding.

[0053] Reference Figure 1 The electrode assembly 10 may include a first electrode 11, a diaphragm 12, and a second electrode 13. The diaphragm 12 may be inserted between the first electrode 11 and the second electrode 13. The electrode assembly 10 may be configured by winding or stacking unit cells, each unit cell including the first electrode 11, the second electrode 13, and the diaphragm 12. First electrode tabs 14 and second electrode tabs 15 extending from one side of each corresponding electrode of the electrode assembly 10 may be provided, such that a protective tape 16 adheres to the surface of each electrode tab, and the electrode tabs partially protrude to the outside of the housing 20 (bag-type housing). See reference. Figure 1 Although the electrode assembly 10 is shown as a wound type, its shape can be, for example, a stacked type or other shapes.

[0054] Reference Figure 1The first electrode tab 14 and the second electrode tab 15 can extend from the first electrode 11 and the second electrode 13 in the same direction, respectively, such that the first electrode tab 14 and the second electrode tab 15 are formed on the same side of the electrode assembly. Additionally, as shown, the first electrode tab 14 and the second electrode tab 15 can be bent in the space between one side surface of the housing 20 and the electrode assembly 10, thereby being housed within the housing. However, for example, the first electrode tab 14 of the first electrode 11 can be formed on one side of the electrode assembly 10, and the second electrode tab 15 of the second electrode 13 can be formed on the other side of the electrode assembly 10.

[0055] As shown in the figure, the first electrode connector 14 can be located on the left end surface of the electrode assembly, and the second electrode connector 15 can be located on the right end surface of the electrode assembly, or on the same end surface as the first electrode connector 14. Here, for ease of description, based on... Figure 1 The secondary battery 100 shown indicates the left and right sides, and its position can be changed when the secondary battery is rotated left and right or up and down.

[0056] Reference Figure 1 The housing 20 can accommodate the electrode assembly 10 and the electrolyte, thereby forming the external shape of the secondary battery. As shown, the housing 20 can be the housing of a pouch-type secondary battery. The pouch-type housing 20 may include a lower housing 22 for accommodating the electrode assembly 10, an upper housing 21 for sealing the upper surface of the electrode assembly 10, and a recessed space 23 for accommodating the electrode assembly 10, the recessed space 23 being formed by pressing and molding the outer material of the pouch. However, the type of secondary battery is not limited to this; for example, the housing can be the housing of a prismatic secondary battery, a cylindrical secondary battery, or a button-type secondary battery. The housing can be formed of at least one of a metal such as stainless steel (SUS), aluminum, aluminum alloy, or nickel-plated steel, a laminate forming the pouch, or a plastic.

[0057] Figure 2 According to embodiments of this disclosure Figure 1 Cross-sectional view of secondary battery 100.

[0058] Reference Figure 2 An exemplary structure obtained by cutting the secondary battery along line Q' can be observed, where line Q' extends from a portion Q of the first electrode tab 14 in the secondary battery 100 to the outside of the housing 20 (where the first electrode tab 14 is not bent) and intersects the secondary battery along a first direction (Y direction) at a predetermined distance. Figure 2In the drawings, the line Q' that intersects a predetermined distance along the first direction (Y direction) from the unbent portion of the first electrode tab 14 may be a line virtually defined in the drawings for ease of understanding, and according to the embodiment, the unbent portion Q of the first electrode tab 14 may be a portion virtually defined in the drawings for ease of understanding. Figure 2 The lower left corner shows the first direction (Y direction) and the second direction (Z direction) intersecting the first direction; these are imaginary directions for ease of understanding. Therefore, line Q' and part Q correspond to... Figure 1 The line Q' and part of Q.

[0059] The first electrode 11 may include a first substrate, a first mixture portion coated with an active substance on one surface of the first substrate, a first uncoated portion of the first substrate exposed on said one surface of the first substrate, and a first insulating layer 11_1 disposed on the first uncoated portion. A first electrode tab 14 (e.g., an electrode tab that will be a tab after being joined together) may extend outward from the first uncoated portion of the first substrate exposed in the first substrate, and the first electrode tab 14 may be electrically connected to the housing 20.

[0060] The second electrode 13 may include a second substrate, a second mixture portion coated with an active substance on one surface of the second substrate, a second uncoated portion exposed on the one surface of the second substrate, and a second insulating layer disposed on the second uncoated portion. A second electrode tab may extend outward from the second uncoated portion exposed in the second substrate, and the second electrode tab may be electrically connected to the housing 20.

[0061] The first electrode 11 can be used as a negative electrode. In this case, the first substrate can be formed of, for example, copper foil or nickel foil, and the first mixture portion coated with the active material on one surface of the first substrate can include, for example, graphite or carbon. The second electrode 13 can be used as a positive electrode. In this case, the second substrate can be formed of, for example, a metal foil such as aluminum or an aluminum alloy, and the second mixture portion coated with the active material on one surface of the second substrate can include, for example, a transition metal oxide. Additionally, the end of the first mixture portion can protrude beyond the end of the second mixture portion.

[0062] A diaphragm 12 may be inserted between the first electrode 11 and the second electrode 13. The diaphragm 12 serves to allow lithium ion movement and prevent short circuits between the first electrode 11 and the second electrode 13. The diaphragm may be formed of, for example, a polyethylene film, a polypropylene film, or a polyethylene-polypropylene film, but this can be varied. In one embodiment, the end of the diaphragm 12 may protrude beyond the end of the first insulating layer 11_1.

[0063] An electrolyte-filled recessed space 23 may exist within the housing 20. The electrolyte can be injected through an electrolyte inlet present on one side surface of the housing 20. As a result, the diaphragm 12, the first electrode 11, and the second electrode 13 can be impregnated with the electrolyte. According to one embodiment, during rolling, the difference between the thickness of the edge portion of the first electrode 11 and the thickness of the center portion of the first electrode 11 can be equal to or less than a predetermined threshold difference. Therefore, the effect of preventing side reactions due to electrolyte accumulation can be anticipated.

[0064] Electrode assembly 10 can be housed in housing 20 such that first electrode 11, second electrode 13, and diaphragm 12 are alternately wound or stacked. Furthermore, one or more electrode assemblies can be stacked such that their long side surfaces are adjacent to each other and can be housed in the housing, and the number of electrode assemblies can be varied.

[0065] Figure 3 This is a view showing an example of a first electrode according to an embodiment of the present disclosure.

[0066] Reference Figure 3 The first electrode 30 can be used as a negative electrode. The first electrode 30 may include a first substrate 31, a first mixture portion 33 on one surface of the first substrate 31 coated with an active material to define a coated portion 31a of the substrate 31, a first uncoated portion 31b exposing the first substrate 31, and a first insulating layer 32 disposed on the first uncoated portion. Furthermore, the first insulating layer 32 may be coated on said one surface of the first substrate 31 such that the thickness A1 of the first insulating layer 32 in the second direction (Z direction) is in the range of 95% to 105% of the thickness B1 of the first mixture portion 33 in the second direction (Z direction). Therefore, during rolling, the difference between the thickness of the edge portion and the thickness of the center portion of the first electrode 30 can be equal to or less than a predetermined threshold difference, thus preventing a reduction in the thickness of the edge portion of the first mixture portion 33. Figure 3 The lower left corner shows the first direction (Y direction) and the second direction (Z direction), which are hypothetical directions for ease of understanding.

[0067] according to Figure 3 The ends and corners of the first insulating layer 32 and the first mixture portion 33 are depicted as angled or inclined. However, this is only a schematic illustration, and for example, the ends and corners may be inclined at a certain angle in the second direction (Z direction).

[0068] according to Figure 3The first insulating layer 32 and the first mixture portion 33 are shown spaced apart by a separation distance. However, this is merely an example and can be modified. For instance, one end of the first insulating layer 32 may be configured to contact one end of the first mixture portion 33, or the first insulating layer 32 may be configured to cover a portion of the first mixture portion 33.

[0069] In one embodiment, the first insulating layer 32 may be applied to one surface of the first substrate 31 after the first mixture portion 33 is applied. However, the first insulating layer 32 may be applied to cover a portion of the first mixture portion 33 after the first mixture portion 33 is applied.

[0070] Figure 4A This is a view illustrating an example of the first electrode 40 according to an embodiment of the present disclosure, shown in a vertical cross-sectional view, while also showing the width C of the region where the first mixture portion 43 slides in the opposite direction (e.g., -Y direction) to the first direction (Y direction). Specifically, Figure 4A A schematic cross-section of the first mixture portion 43 and the first insulating layer 42 in a coated state is shown, wherein the first mixture portion 43 is coated with an active material only on one surface of the first substrate 41, which serves as the negative electrode, and the first insulating layer 42 is disposed on the first uncoated portion. Figure 4A The lower left corner shows a first direction (Y direction) and a second direction (Z direction) intersecting the first direction; these are imaginary directions for ease of understanding. The width C of the sliding region at the end of the first mixture portion 43 in the direction opposite to the first direction (Y direction) can be a line virtually defined in the drawing for ease of understanding. Furthermore, according to... Figure 4A The width C of the sliding region at the end of the first mixture portion 43 in the opposite direction to the first direction (Y direction) can be represented as the width from the portion where the first mixture portion 43 begins to slope to the portion where the first mixture portion 43 contacts the first insulating layer 42. Figure 4A In the text, the description focuses on the width C.

[0071] In one embodiment, at the boundary region between the end of the first mixture portion 43 and the first insulating layer 42, one end of the first insulating layer 42 may be configured to contact one end of the first mixture portion 43. Therefore, the width C of the region where the end of the first mixture portion 43 slides can be reduced in the opposite direction (Y direction) by the first insulating layer 42. Thus, during rolling, the difference between the thickness of the edge portion of the first electrode 40 and the thickness of the center portion of the first electrode 40 can be equal to or less than a predetermined threshold difference. Therefore, it is possible to suppress the reduction in thickness of the edge portion of the first mixture portion 43 and prevent side reactions caused by electrolyte aggregation.

[0072] Figure 4B This is a view illustrating an example of a first electrode 50 according to an embodiment of the present disclosure, while also showing the width A2 of the first insulating layer 52 in the first direction (Y direction) and the width D1 of the first uncoated portion in the first direction (Y direction). Specifically, Figure 4B A schematic cross-section of the first mixture portion 53 and the first insulating layer 52 in a coated state is shown, wherein the first mixture portion 53 is coated with an active material only on one surface of the first substrate 51, which serves as the first electrode 50 as the negative electrode, and the first insulating layer 52 is disposed on the first uncoated portion. Figure 4B The lower left corner shows a first direction (Y direction) and a second direction (Z direction) intersecting the first direction; these are imaginary directions for ease of understanding. For ease of understanding, widths A2 and D1 can be lines virtually defined on the attached diagram. According to... Figure 4B The width A2 of the first insulating layer 52 in the first direction (Y direction) can be shown as the width from the most protruding part of the first insulating layer 52 in the opposite direction of the first direction (Y direction) to the part of the first insulating layer 52 that contacts the first mixture portion 53, and the width D1 of the first uncoated portion in the first direction (Y direction) can be shown as the width from the most protruding part of the first substrate 51 in the opposite direction of the first direction (Y direction) to the part of the first insulating layer 52 that contacts the first mixture portion 53. Figure 4B Focus on widths A2 and D1.

[0073] In one embodiment, at the boundary region between the end of the first mixture portion 53 and the first insulating layer 52, one end of the first insulating layer 52 may be configured to contact (e.g., directly contact) one end of the first mixture portion 53. The width A2 of the first insulating layer 52 in the first direction (Y direction) may be in the range of 10% to 75% of the width D1 of the first uncoated portion in the first direction (Y direction). For example, when D1 is 10 mm, A2 may be 3 mm. As a result, the thickness reduction of the edge portion of the first mixture portion 53 can be prevented. Furthermore, in the above example, when A2 has a width of 7.5 mm or less, interference with soldering using the first substrate 51 as a current collector (an element configured to allow electron movement during the charging and discharging of the secondary battery) can be prevented, thus preventing an increase in resistance.

[0074] Figure 5A and Figure 5B This is a view showing an example of first electrodes 50 and 60, wherein the first insulating layer and the first mixture portion are disposed at a predetermined separation distance according to an embodiment of the present disclosure.

[0075] Reference Figure 5A and Figure 5BEach of the first electrodes 50 and 60 used as negative electrodes may include a first substrate 51 or 61, a first mixture portion 53 or 63 coated with an active substance on one surface of the first substrate, a first uncoated portion exposing the first substrate, and a first insulating layer 52 or 62 disposed on the first uncoated portion. Furthermore, the first insulating layer 52 or 62 and the first mixture portion 53 or 63 may be arranged to be spaced apart from each other by a predetermined separation distance.

[0076] according to Figure 5B The width D2 of the first insulating layer 62 and the first mixture portion 63 in the first direction (Y direction) (in which the first insulating layer 62 and the first mixture portion 63 are set to be spaced apart from each other by a predetermined separation distance), the width D1 of the first uncoated portion in the first direction (Y direction), and the width A3 of the first insulating layer 62 in the first direction (Y direction) can be lines virtually defined in the drawings for ease of understanding. Figure 5B The lower left corner shows the first direction (Y direction) and the second direction (Z direction) that intersects the first direction; these are hypothetical directions for ease of understanding.

[0077] Furthermore, the width D2 in the first direction (Y direction) (in which the first insulating layer 62 and the first mixture portion 63 are set to be spaced apart from each other by a predetermined separation distance) can be represented as the width from the most protruding portion of the first insulating layer 62 in the first direction (Y direction) to the most protruding portion of the first mixture portion 63 in the opposite direction of the first direction (Y direction). The width D1 of the first uncoated portion in the first direction (Y direction) can be represented as the width from the most protruding portion of the first substrate 61 in the opposite direction of the first direction (Y direction) to the most protruding portion of the first mixture portion 63 in the opposite direction of the first direction (Y direction). The width A3 of the first insulating layer 62 in the first direction (Y direction) can be represented as the width from the most protruding portion of the first insulating layer 62 in the opposite direction of the first direction (Y direction) to the most protruding portion of the first insulating layer 62 in the first direction (Y direction).

[0078] In one embodiment, the sum of the width D2, determined by a predetermined distance spaced between the first insulating layer 62 and the first mixture portion 63 in the first direction (Y direction), and the width A3 of the first insulating layer 62 in the first direction (Y direction), can be equal to or less than (e.g., less than or equal to) 75% of the width D1 of the first uncoated portion in the first direction (Y direction). Therefore, short circuits caused by contact between the first electrode 60 and the second electrode due to exposure of the first substrate 61 can be prevented.

[0079] In one embodiment, the width D2 of the first insulating layer 62 and the first mixture portion 63 spaced apart from each other in the first direction (Y direction) can be predetermined to be in the range of 1 mm or less. Therefore, even if the electrolyte is impregnated into the electrode assembly after electrolyte injection, electrolyte pooling at the end of the first electrode 60 can be prevented, thus preventing side reactions.

[0080] according to Figure 5B The ends of the first insulating layer 62 and the first mixture portion 63 are depicted as angled. However, this is merely illustrative, and as... Figure 5A As shown, the ends of the first insulating layer 62 and the first mixture portion 63 may have inclined ends.

[0081] Figure 6A This is a view showing the state in which the first insulating layer 72 of the first electrode 70 according to an embodiment of the present disclosure is configured to cover a portion of the first mixture portion 73. Figure 6A The first electrode 70, used as a negative electrode, may include a first substrate 71, a first mixture portion 73 coated with an active substance on one surface of the first substrate 71, a first uncoated portion exposing the first substrate 71, and a first insulating layer 72 disposed on the first uncoated portion. Figure 6A The lower left corner shows a first direction (Y direction) and a second direction (Z direction) intersecting the first direction; these are hypothetical directions for ease of understanding. Here, the first electrode 70 can be a negative electrode.

[0082] In one embodiment, the first insulating layer 72 may be configured to cover a portion of the first mixture portion 73. As shown, the first insulating layer 72 may be configured to cover the upper portion of the first mixture portion 73. For ease of understanding, the width D3 of the area where the first insulating layer 72 covers a portion of the first mixture portion 73 in the first direction (Y direction) may be a line virtually defined in the figures.

[0083] Figure 6B This is a vertical cross-sectional view showing an example of an electrode assembly 200 according to an embodiment of the present disclosure, and also showing a first electrode 70, a diaphragm 90 and a second electrode 80.

[0084] Reference Figure 6BThe electrode assembly 200 may include: a first electrode 70, comprising a first substrate 71, a first mixture portion 73 coated with an active material on one surface of the first substrate 71, a first uncoated portion exposing the first substrate 71, and a first insulating layer 72 disposed on the first uncoated portion; a second electrode 80, comprising a second substrate 81, a second mixture portion 83 coated with an active material on one surface of the second substrate 81, a second uncoated portion exposing the second substrate 81, and a second insulating layer 82 disposed on the second uncoated portion; and a diaphragm 90 inserted between the first electrode 70 and the second electrode 80. The electrode assembly 200 may include a structure in which the first electrode 70, the diaphragm 90, and the second electrode 80 are repeatedly stacked in a second direction (Z direction). However, Figure 6B The vertical cross-sectional view of the electrode assembly shown is only one embodiment; the thickness of the electrode assembly or the number of electrodes and diaphragms can be varied. The first electrode 70 can correspond to... Figure 6A The first electrode 70. In one embodiment, the end of the first mixture portion 73 may protrude beyond the end of the second mixture portion 83 in the opposite direction to the first direction (Y direction). Figure 6B The lower left corner shows the first direction (Y direction) and the second direction (Z direction) that intersects the first direction; these are hypothetical directions for ease of understanding.

[0085] The first electrode 70 can be used as a negative electrode. In one embodiment, the first mixture portion 73 can be disposed on one surface of the first substrate 71, and the first insulating layer 72 can be disposed on the first uncoated portion exposing the first substrate 71. However, this is only one embodiment, and the first insulating layer 72 and the first mixture portion 73 can be disposed on both surfaces of the first substrate 71. In addition, the diaphragm 90 and the second electrode 80 can be disposed on the upper or lower side of the first electrode 70 in the second direction (Z direction).

[0086] The second electrode 80 can be used as a positive electrode. In one embodiment, the second mixture portion 83 can be disposed on one surface of the second substrate 81, and the second insulating layer 82 can be disposed on the second uncoated portion exposing the second substrate 81. Additionally, the second insulating layer 82 can prevent short circuits caused by contact between the first mixture portion 73 and the second mixture portion 83 when the diaphragm 90 contracts. However, this is only one embodiment, and the second insulating layer 82 and the second mixture portion 83 can be disposed on both surfaces of the second substrate 81. Furthermore, the diaphragm 90 and the first electrode 70 can be disposed on the upper or lower side of the second electrode 80 in the second direction (Z direction).

[0087] The diaphragm 90 can be inserted between the first electrode 70 and the second electrode 80, and can allow lithium ion movement while preventing short circuits between the first electrode 70 and the second electrode 80. In one embodiment, the end of the diaphragm 90 can protrude beyond the end of the first insulating layer 72 in the opposite direction (Y direction). Therefore, contact between the first electrode 70 and the second electrode 80 can be prevented, and short circuits can be prevented.

[0088] In one embodiment, the thickness of the first insulating layer 72 coated on one surface of the first substrate 71 in the second direction (Z direction) can be in the range of 95% to 105% of the thickness of the first mixture portion 73 in the second direction (Z direction). As a result, the difference between the thickness of the edge portion of the first electrode 70 and the thickness of the center portion of the first electrode 70 during rolling can be equal to or less than a predetermined threshold difference, thus suppressing the reduction in thickness of the edge portion of the first electrode 70 and preventing electrolyte accumulation after electrolyte injection.

[0089] In one embodiment, the first insulating layer 72 may be configured to cover a portion of the first mixture portion 73. Additionally, the diaphragm 90 and the second electrode 80 may be disposed on top of the area where the first insulating layer 72 covers the first mixture portion 73. As a result, contact between the first mixture portion 73 and the second mixture portion 83 is prevented even when the diaphragm 90 contracts.

[0090] Reference Figure 6B The width D3 of the region of the first insulating layer 72 covering a portion of the first mixture portion 73 in the first direction (Y direction), and the width E between the most convex portion of the first mixture portion 73 in the opposite direction of the first direction (Y direction) and the most convex portion of the second mixture portion 83 in the opposite direction of the first direction (Y direction), can be lines virtually defined in the drawings for ease of understanding. In one embodiment, width D3 and width E can be the same as each other. Therefore, even when the diaphragm 90 contracts, short circuits caused by contact between electrodes can be prevented.

[0091] Figure 7 This is a view comparing the differences between the prior art and embodiments of the present disclosure depending on the presence or absence of a sliding region at the electrode edge portion.

[0092] Figure 7 Comparative examples of electrode assemblies 720 and 710 are schematically shown, each comprising a first electrode S1 or S2 that can be used as a negative electrode, a diaphragm, and a second electrode that can be used as a positive electrode. In one embodiment, electrode assembly 720 can be coupled with… Figure 2 The electrode assembly 10 is basically the same. Although from Figure 7The first electrode S1 of the electrode assembly 720 is omitted. Figure 2 The first electrode S1 includes a first electrode tab 14 and a first insulating layer 11_1, but this is only a schematic representation for ease of comparison. According to various embodiments, the first electrode S1 may include a first electrode tab and a first insulating layer. Additionally, the first electrode S2 included in the electrode assembly 710 according to the comparative example may not include an insulating layer. Therefore, the thickness of the central portion and the thickness of the edge portion of the first mixture portion included in the electrode assembly 710 may differ from each other during rolling. Consequently, a sliding region P may appear at the edge portion of the first electrode S2.

[0093] According to various embodiments of this disclosure, in the first electrode S1 of the electrode assembly 720, the difference between the thickness of the edge portion of the first electrode S1 and the thickness of the center portion of the first electrode S1 during rolling can be equal to or less than a predetermined threshold difference due to the first insulating layer, thus preventing side reactions caused by electrolyte accumulation. Compared to the sliding region P of the edge portion of the first electrode S2 of the electrode assembly 710, even after the electrolyte is injected into the electrode assembly, electrolyte accumulation at the edge portion of the first electrode can be prevented, thus preventing side reactions. For example, side effects such as monomer cycle degradation caused by the occurrence of side reactions can be prevented.

[0094] Electrode assemblies 710 and 720 are merely comparative embodiments, and the shape, form, number, and length of the electrode assemblies, first electrode, diaphragm, and second electrode of this disclosure can vary. Various embodiments may differ, and, for example, while the electrode assembly may have a structure in which the electrodes and diaphragm are stacked as shown, the electrode assembly may alternatively have a wound structure.

[0095] In a pouch cell where positive and negative electrodes are alternately laminated to create a single cell, sliding can occur at the end of the negative electrode plate. Therefore, the thickness of the end of the negative electrode plate and the thickness of the mixed portion of the negative electrode plate can be different from each other.

[0096] To facilitate lithium-ion movement, an electrolyte can be injected into the secondary battery. In addition to the impregnated electrolyte, an extra excess electrolyte, i.e., a free electrolyte, can be injected as needed. However, when sliding occurs within the negative electrode plate, the thickness of the edge portion of the negative electrode plate can become thinner, allowing electrolyte to accumulate in that area. Consequently, during battery cycling, side reactions can occur due to the accumulated electrolyte. Furthermore, side effects such as single-cell cycle degradation can occur.

[0097] According to various embodiments of this disclosure, although the insulating layer is disposed in the boundary region of the end of the mixture portion and one end of the insulating layer is configured to contact the end of the mixture portion, the thickness reduction of the edge portion of the electrode mixture portion can be prevented because the width of the insulating layer can be in the range of 10% to 75% of the width of the uncoated portion of the exposed substrate, and the increase in resistance due to interference with welding (welding is performed to use the substrate as a current collector (a component configured to allow electron movement during charging and discharging)).

[0098] According to various embodiments of this disclosure, although the insulating layer is disposed at a predetermined separation distance from the mixture portion, the sum of the separation distance and the width of the insulating layer can be equal to or less than 75% of the width of the substrate, thus preventing short circuits caused by contact between electrodes.

[0099] According to various embodiments of this disclosure, although the insulating layer is configured to cover a portion of the first mixture portion, since the width of the area of ​​the portion of the first mixture portion covered by the insulating layer in the first direction is the same as the width between the most convex portion of the first mixture portion in the opposite direction and the most convex portion of the second mixture portion in the opposite direction, short circuits caused by contact between electrodes can be prevented even when the diaphragm shrinks.

[0100] Although this disclosure has been described with reference to embodiments and accompanying drawings illustrating various aspects thereof, this disclosure is not limited thereto. Various modifications and alterations can be made by those skilled in the art to which this disclosure pertains, within the spirit of the present disclosure and within the scope of the following claims and their equivalents.

[0101] Example embodiments have been disclosed herein, and although specific terminology has been used, it is used and interpreted in a general and descriptive sense only and not for limiting purposes. In some instances, as will be apparent to those skilled in the art at the time of filing this application, unless otherwise specifically indicated, features, characteristics, and / or elements described in connection with particular embodiments may be used alone or in combination with features, characteristics, and / or elements described in connection with other embodiments. Therefore, those skilled in the art will understand that various changes in form and detail may be made without departing from the spirit and scope of the invention as set forth in the following claims.

Claims

1. An electrode assembly, comprising: The first electrode includes a first substrate, a first mixture portion including an active material and coated on a surface of the first substrate, a first uncoated portion on the surface of the first substrate, and a first insulating layer on the first uncoated portion, wherein the first uncoated portion of the first substrate is exposed. The second electrode includes a second substrate, a second mixture portion including an active material and coated on one surface of the second substrate, a second uncoated portion on the one surface of the second substrate, and a second insulating layer on the second uncoated portion, wherein the second uncoated portion of the second substrate is exposed. as well as A diaphragm is located between the first electrode and the second electrode.

2. The electrode assembly according to claim 1, wherein, The end of the first mixture portion protrudes beyond the end of the second mixture portion.

3. The electrode assembly according to claim 1, wherein, The first insulating layer is coated on one surface of the first substrate, and the first insulating layer has a thickness in the range of 95% to 105% of the thickness of the first mixture portion.

4. The electrode assembly according to claim 1, wherein, The end of the diaphragm protrudes beyond the end of the first insulating layer.

5. The electrode assembly according to claim 1, wherein, One end of the first insulating layer contacts one end of the first mixture portion.

6. The electrode assembly according to claim 5, wherein, The width of the first insulating layer is in the range of 10% to 75% of the width of the first uncoated portion.

7. The electrode assembly according to claim 1, wherein, The first insulating layer and the first mixture portion are spaced apart by a predetermined separation distance.

8. The electrode assembly according to claim 7, wherein, The sum of the predetermined separation distance and the width of the first insulating layer is equal to or less than 75% of the width of the first uncoated portion.

9. The electrode assembly according to claim 1, wherein, The first insulating layer covers a portion of the first mixture.

10. The electrode assembly according to claim 9, wherein, The width of the portion of the first insulating layer covering the first mixture portion in the first direction is the same as the width between the most convex portion of the first mixture portion in the opposite direction of the first direction and the most convex portion of the second mixture portion in the opposite direction of the first direction.

11. The electrode assembly according to claim 9, wherein, The diaphragm and the second electrode are on top of the area where the first insulating layer covers the portion of the first mixture.

12. A secondary battery, comprising: An electrode assembly comprising stacked unit cells, each of which includes a first electrode, a diaphragm, and a second electrode; Housing that houses the electrode assembly; as well as Electrolyte, in the shell, The first electrode includes: First substrate, The first mixture portion includes an active substance and is coated on one surface of the first substrate. On the first uncoated portion of said one surface of the first substrate, the first uncoated portion of the first substrate is exposed, and A first insulating layer is disposed on the first uncoated portion. The second electrode includes: Second substrate, The second mixture portion includes an active substance and is coated on one surface of the second substrate. On said one surface of the second substrate, a second uncoated portion is exposed, and A second insulating layer is disposed on the second uncoated portion, and The diaphragm is located between the first electrode and the second electrode.

13. The secondary battery according to claim 12, wherein, The end of the first mixture portion protrudes beyond the end of the second mixture portion.

14. The secondary battery according to claim 12, wherein, The first insulating layer is coated on one surface of the first substrate, and the first insulating layer has a thickness in the range of 95% to 105% of the thickness of the first mixture portion.

15. The secondary battery according to claim 14, wherein, The end of the diaphragm protrudes beyond the end of the first insulating layer.

16. The secondary battery according to claim 12, wherein, One end of the first insulating layer contacts one end of the first mixture portion.

17. The secondary battery according to claim 16, wherein, The width of the first insulating layer is in the range of 10% to 75% of the width of the first uncoated portion.

18. The secondary battery according to claim 12, wherein, The first insulating layer and the first mixture portion are spaced apart by a predetermined separation distance.

19. The secondary battery according to claim 12, wherein, The first insulating layer covers a portion of the first mixture.

20. The secondary battery according to claim 12, wherein, The difference between the thickness of the edge portion of the first electrode and the thickness of the center portion of the first electrode is equal to or less than a predetermined threshold difference.

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