Secondary battery

Abstract

The present invention relates to a secondary battery in which the upper part of a second electrode is insulated by an insulating member attached or provided to a first electrode, the second electrode, or a separator of an electrode assembly, thereby preventing shorting between the second electrode and a first current collector plate of the electrode assembly. As one example, the present invention provides the secondary battery comprising: an electrode assembly having a first electrode, a separator and a second electrode; a case, which accommodates the electrode assembly and has an open bottom; a terminal electrically connected to the first electrode of the electrode assembly and exposed to the outside of the case through the top side of the case; a first current collector plate, which is interposed between the upper surface of the electrode assembly and the case and electrically connects the first electrode plate and the terminal; and a cap plate for sealing the bottom of the case, wherein the electrode assembly includes an insulating member attached to one from among the top of the first electrode, the top of the separator, and the top of the second electrode.

Description

secondary battery

[0001] The present disclosure relates to a secondary battery.

[0002] Secondary batteries are power storage systems that offer superior energy density by converting electrical energy into chemical energy and storing it. Compared to non-rechargeable primary batteries, secondary batteries are rechargeable and are widely used in IT devices such as smartphones, cellphones, laptops, and tablet PCs. Recently, interest in electric vehicles has grown to prevent environmental pollution, leading to the adoption of high-capacity secondary batteries in electric vehicles. These secondary batteries require high density, high output, and stability.

[0003] The above-described information disclosed in the background technology of this invention is only intended to improve understanding of the background of the present invention, and therefore may include information that does not constitute prior art.

[0004] The present invention can prevent a short circuit between the second electrode of the electrode assembly and the first current collector plate by insulating the upper part of the second electrode by an insulating member attached or provided to the first electrode, second electrode or separator of the electrode assembly.

[0005] However, the technical problems to be solved by the present invention are not limited to the problems described above, and other problems not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0006] According to one embodiment of the present invention for solving the above technical problem, a secondary battery includes an electrode assembly having a first electrode, a separator, and a second electrode, a case in which the electrode assembly is accommodated and has an open bottom, a terminal electrically connected to the first electrode of the electrode assembly, penetrating an upper portion of the case and exposed to the outside of the case, a first current collecting plate interposed between an upper surface of the electrode assembly and the case and electrically connecting the first electrode plate and the terminal, and a cap plate sealing the bottom portion of the case, wherein the electrode assembly may include an insulating member attached to any one of an upper portion of the first electrode, an upper portion of the separator, and an upper portion of the second electrode.

[0007] The first electrode may include a first electrode coated portion coated with a first electrode active material on a sheet-shaped first substrate, and a first electrode uncoated portion not coated with the first electrode active material on the upper portion of the first substrate.

[0008] The above insulating member may be in the form of a tape attached to cover the upper portion of the first electrode non-conductive portion.

[0009] The insulating member is attached to both sides of the first electrode, and each insulating member has a first region, which is the lower region, attached to both sides of the first electrode's uncoated portion, and a second region, which is located on the upper side of the first region, extends upward from both sides of the first electrode's uncoated portion so that the adhesives facing each other can be attached.

[0010] The above insulating member can be bent in the direction of the winding core so that the second region protrudes further than the upper end of the separator.

[0011] The insulating member may be interposed between the second electrode of the electrode assembly and the first collector plate.

[0012] The above insulating member may not be attached to the upper portion of the first electrode closest to the core.

[0013] The first electrode non-conductive portion may include a plurality of first electrode tabs spaced apart from each other at the upper end and protruding upward from the second electrode and the separator, and the first electrode tabs may have a first bending point bent in the direction of the winding.

[0014] The above insulating member can be attached so as to cover the upper end of the winding tip of the first electrode non-coated portion in which the first electrode tab is not provided.

[0015] The above insulating member may be in the form of a tape attached to cover the upper portion of the second electrode.

[0016] The insulating member is attached to both sides of the second electrode, and the lower part is attached to both sides of the second electrode, and extends upward from both sides of the second electrode so as to protrude further than the upper end of the second electrode so that the adhesives facing each other can be attached to each other.

[0017] The insulating member may have an upper end positioned lower than the first bending point of the first electrode tab, and a lower end positioned higher than the first electrode coating portion of the first electrode.

[0018] The above insulating member can overlap with the first electrode non-conductive portion.

[0019] The above insulating member can be attached so as to cover the upper end of the winding tip on the second electrode.

[0020] The above insulating member can be attached so as to cover the entire upper portion of the second electrode.

[0021] The separator may include a first separator interposed between a first surface of the first electrode and a second surface of the second electrode, and a second separator interposed between the second surface of the first electrode and the first surface of the first electrode, wherein the first separator may include a first surface opposite the first surface of the first electrode and a second surface opposite the second surface of the second electrode, and the second separator may include a first surface opposite the first surface of the second electrode and a second surface opposite the second surface of the first electrode.

[0022] The above insulating member can bond between the upper part of the second surface of the first separator facing the second electrode and the upper part of the first surface of the second separator.

[0023] The above insulating member can be attached between the upper ends of the winding ends of the first separator and the second separator.

[0024] The above insulating material may be a double-sided tape or adhesive.

[0025] The upper part of the first separator and the upper part of the second separator can be bonded to cover the upper part of the second electrode.

[0026] According to the present invention, a secondary battery can be provided that can prevent a short circuit between a second electrode of an electrode assembly and a first current collector plate by insulating the upper portion of the second electrode by an insulating member attached or provided to the first electrode, second electrode, or separator of the electrode assembly.

[0027] However, the effects that can be obtained through the present invention are not limited to the effects described above, and other technical effects that are not mentioned can be clearly understood by those skilled in the art from the description of the invention described below.

[0028] The following drawings attached to this specification illustrate preferred embodiments of the present invention, and together with the detailed description of the invention described below, serve to further understand the technical idea of ​​the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.

[0029] Figure 1 is a perspective view illustrating a secondary battery according to the present invention.

[0030] Figure 2 is an example of a cross-sectional view of the secondary battery illustrated in Figure 1.

[0031] FIG. 3 is an example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in FIG. 2.

[0032] Figure 4 is an exploded view showing the first electrode and the second electrode before the electrode assembly of Figure 3 is wound.

[0033] FIG. 5 is another example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in FIG. 2.

[0034] Figure 6 is an exploded view showing the first electrode and the second electrode before the electrode assembly of Figure 5 is wound.

[0035] Fig. 7 is another example of an enlarged view showing the upper part of the electrode assembly in the secondary battery illustrated in Fig. 2.

[0036] Figure 8 is an exploded view showing the first electrode and the second electrode before the electrode assembly of Figure 7 is wound.

[0037] Figure 9 is an enlarged view of part A of Figure 7.

[0038] FIG. 10 is another example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in FIG. 2.

[0039] Figure 11 is an enlarged view of part B of Figure 10.

[0040] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms or words used in this specification and claims should not be interpreted as limited to their typical or dictionary meanings, and should be interpreted with meanings and concepts that conform to the technical spirit of the present invention based on the principle that the inventor can appropriately define the concept of a term to best explain his or her own invention. Therefore, the embodiments described in this specification and the configurations illustrated in the drawings are only some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention. Therefore, it should be understood that various equivalents and modified examples may exist as substitutes for them at the time of filing this application.

[0041] Additionally, when used herein, the terms "comprise", "include" and / or "comprising", "including" specify the presence of stated features, numbers, steps, operations, elements, elements and / or groups thereof, but do not preclude the presence or addition of one or more other features, numbers, operations, elements, elements and / or groups thereof.

[0042] Additionally, to facilitate understanding of the invention, the attached drawings are not drawn to scale and some components may be exaggerated in size. Furthermore, identical components may be assigned the same reference numbers in different embodiments.

[0043] The statement that two compared objects are "identical" means "substantially identical." Therefore, "substantially identical" may include deviations considered low in the art, such as deviations of less than 5%. Furthermore, uniformity of a parameter over a given region may imply uniformity on average.

[0044] Although terms like "first" and "second" are used to describe various components, these components are not limited by these terms. These terms are used merely to distinguish one component from another, and unless otherwise specified, a "first" component may also be a "second" component.

[0045] Throughout the specification, unless otherwise specifically stated, each element may be singular or plural.

[0046] Any configuration being placed "on (or under)" or "above (or below)" a component may mean not only that any configuration is placed in contact with the upper surface (or lower surface) of said component, but also that other configurations may intervene between said component and any configuration placed on (or below) said component.

[0047] Additionally, when it is described that a component is "connected," "coupled," or "connected" to another component, it should be understood that the components may be directly connected or connected to one another, but that other components may also be "interposed" between the components, or that each component may be "connected," "coupled," or "connected" through another component. Furthermore, when it is said that a part is electrically coupled to another part, this includes not only cases where they are directly connected, but also cases where they are connected with another element in between.

[0048] When reference is made throughout the specification to "A and / or B," this means A, B, or A and B, unless otherwise stated. In other words, "and / or" includes all or any combination of the listed items. When reference is made to "C through D," this means C or more and D or less, unless otherwise stated.

[0049] The terminology used herein is for the purpose of describing embodiments of the present disclosure and is not intended to be limiting of the present disclosure.

[0050] FIG. 1 is a perspective view illustrating a secondary battery according to the present invention, and FIG. 2 is a cross-sectional view of the secondary battery illustrated in FIG. 1.

[0051] As illustrated in FIGS. 1 and 2, the secondary battery (100) may include an electrode assembly (110), a case (120) that accommodates the electrode assembly (110) and an electrolyte therein, a terminal (150) coupled to a terminal hole provided at one end of the case (120), for example, an upper end, and a cap plate (160) that seals the other end of the case (110), for example, a lower end. The secondary battery (100) may further include a first collector plate (130) that electrically connects a first electrode (111) of the electrode assembly (110) and the terminal (150), and a second collector plate (140) that electrically connects a second electrode (112) of the electrode assembly (110) and the case (120).

[0052] The electrode assembly (110) may include a separator (113), a first electrode (111) and a second electrode (112) positioned with the separator (113) between them, and may be wound in a jelly-roll shape.

[0053] The first electrode (111) includes a first substrate and a first active material layer positioned on the first substrate. A first electrode tab may extend outward from a first non-conductive portion of the first substrate where the first active material layer is not positioned, and the first electrode tab (111b) may be electrically connected to a terminal (150) via a first current collector (130).

[0054] The second electrode (112) includes a second substrate and a second active material layer positioned on the second substrate. A second electrode tab may extend outward from a second non-conductive portion of the second substrate where the second active material layer is not positioned, and the second electrode tab (112b) may be electrically connected to the case (120) via the second current collector (140). The first electrode tab (111b) and the second electrode tab (112b) may be positioned in opposite directions in the electrode assembly (110). The first electrode (111) may function as an anode. In this case, the first substrate may be composed of, for example, an aluminum foil, and the first active material layer may include, for example, a transition metal oxide. The second electrode (112) may function as an cathode. In this case, the second substrate may be composed of, for example, a copper foil or a nickel foil, and the second active material layer may include, for example, graphite.

[0055] The separator (113) functions to prevent short circuiting between the first electrode (111) and the second electrode (112) while allowing the movement of lithium ions. The separator (113) may be composed of, for example, a polyethylene film, a polypropylene film, a polyethylene-polypropylene film, etc.

[0056] The case (120) accommodates the electrode assembly (110) and the electrolyte, and together with the terminal (150) and the cap assembly (160), forms the outer shape of the secondary battery (100). The case (120) may include a body portion (121) having a roughly cylindrical shape, and an upper portion (122) connected to one side of the body portion (121). An inwardly deformed bead portion (123) may be positioned in the body portion (121), and an inwardly bent crimping portion (124) may be positioned at an open end of the body portion (121). The upper portion (122) may be provided with a terminal hole (122a) penetrating the center. The upper portion (122) may be coupled by having a terminal (150) inserted into the terminal hole (122a). An insulating member (125, 126, 127) for sealing and electrical insulation may be further interposed between the terminal hole (122a) and the terminal (150).

[0057] The beading portion (123) can prevent the electrode assembly (110) from moving inside the case (120) and facilitate the fixing of the cap gasket (128) and the cap plate (160). The crimping portion (124) can firmly fix the cap plate (160) by pressing the edge of the cap plate (160) through the cap gasket (128). The case (123) can be made of, for example, nickel-plated iron.

[0058] The first collector plate (130) may have one surface that contacts and is coupled to the first electrode tab of the electrode assembly (110), and the other surface that contacts and is coupled to the terminal (150). The first collector plate (130) may be welded to the first electrode tab of the electrode assembly (110) and electrically connected. The first collector plate (130) may be welded and electrically connected while the other surface is in contact with the terminal (150).

[0059] The second collector plate (140) may have a central portion (141) that contacts and is coupled with the second electrode tab of the electrode assembly (110), and an edge portion (142) that contacts and is coupled with the body portion (121) of the case (120). The second collector plate (140) may be electrically connected by having the central portion (141) welded to the second electrode tab of the electrode assembly (110). The second collector plate (140) may be electrically connected by having the edge portion (142) welded in a state in which it contacts the beading portion (123) of the case (120).

[0060] The terminal (150) may include a terminal plate (151) positioned on the outside of the case (120), and a fastening member (152) that penetrates and connects the terminal plate (151) and the case (120). The terminal plate (151) may have a terminal hole (151a) penetrating through its center. The fastening member (152) may be fixed by pressing the terminal plate (151) through the terminal hole (122a) of the upper portion (122) and the terminal hole (151a) of the terminal plate (151) from the inside of the case (120). An insulating member (125, 126, 127) for electrical insulation may be interposed between the terminal (150) and the case (120). The fastening member (152) may further have a terminal groove (153) extending inward from the center. The terminal (150) can be externally welded to the first collector plate (140) through the terminal groove (153). The terminal (150) can be electrically connected to the first electrode (111) of the electrode assembly (110) through the first collector plate (140). The terminal (150) can have a different polarity from the case (120).

[0061] The cap plate (160) can be secured to the inside of the crimping portion (124) via the cap gasket (128) to seal the case (120). The cap plate (160) can include a safety vent (165) that is thinner than other areas due to a notch. When gas is generated due to overcharging or abnormal operation of the secondary battery (100), the safety vent (165) provided in the cap plate (160) can be cut along the notch. The cut safety vent (165) can prevent an explosion of the secondary battery (100) by releasing the gas to the outside.

[0062] However, the present invention is not limited thereto, and the case may be configured in various shapes, such as circular or pouch-shaped. In addition, the case may be configured of a metal such as aluminum, aluminum alloy, nickel-plated steel, or a laminate film or plastic forming a pouch.

[0063] FIG. 3 is an example of an enlarged view of the upper portion of the electrode assembly in the secondary battery illustrated in FIG. 2. FIG. 4 is an exploded view showing the first electrode (111) and the second electrode (112) of the electrode assembly of FIG. 3 before it is wound. Hereinafter, with reference to FIGS. 3 and 4, the structure of the electrode assembly (110) in the secondary battery (100) will be described.

[0064] First, the first collector plate (130) may be a circular metal plate having a shape corresponding to the upper surface (110a) of the electrode assembly (110). The planar size of the first collector plate (130) may be equal to or smaller than the size of the upper surface (110a) of the electrode assembly (110). The first collector plate (130) may be fixed and electrically connected to the first electrode tab (111b) of the electrode assembly (110) by welding while the lower surface thereof is in contact with the upper surface (110a) of the electrode assembly (110). The first collector plate (130) may be fixed and electrically connected to the terminal (150) by welding while the center of the upper surface thereof is in contact with the lower surface of the terminal (150). The first collector plate (130) serves as a passage for current flow between the first electrode plate (121) of the electrode assembly (120) and the terminal (150). The first collector plate (130) may be welded to the electrode assembly (110), then housed in the case (110), and then welded to the terminal (150). The central region of the first collector plate (130), which is in contact with and welded to the lower surface of the terminal (150), may be positioned lower than other regions. The first collector plate (130) may have a shape in which the central region is concave downward. That is, the distance between the first collector plate (130) and the electrode assembly (110) may be closer in the central region than in other regions.

[0065] The electrode assembly (110) may have a first electrode tab (111a) of a first electrode plate (111) positioned at the upper portion, and a second electrode tab (112a) of a second electrode plate (112) positioned at the lower portion.

[0066] The first electrode (111) may be coated with a first electrode active material on one or both sides of a sheet-shaped first substrate. Hereinafter, the first electrode (111) will be referred to as a first electrode coated portion (111c) where the first electrode active material is coated on the first substrate. Such a first electrode (111) may have a first electrode uncoated portion (111a) on the upper end where the first electrode active material is not coated. In addition, the first electrode uncoated portion (111a) may include a plurality of first electrode tabs (111b). The plurality of first electrode tabs (111b) may be positioned on the upper end of the first electrode uncoated portion (111a) and may be arranged to be spaced apart from each other in one direction before winding. Such a plurality of first electrode tabs (111b) may not be provided at the winding end. That is, compared to the upper end of the first electrode non-coated portion (111a) of the winding tip, the first electrode tab (111b) may protrude further upward. A plurality of such first electrode tabs (111b) may be formed on the first electrode non-coated portion (111a) by laser notching, ultrasonic cutting, or punching. The first electrode tabs (111b) may protrude further upward in the electrode assembly (110) compared to the second electrode (112) and the separator (113).

[0067] The second electrode (112) may be coated with a second electrode active material on one or both sides of a sheet-shaped second substrate. Hereinafter, the region of the second electrode (112) where the second electrode active material is coated on the second substrate will be referred to as a second electrode coated portion (112c). The second electrode (112) may have a second electrode uncoated portion (112a) on the lower portion where the second electrode active material is not coated. In addition, the second electrode uncoated portion (112a) may include a plurality of second electrode tabs (112b). The plurality of second electrode tabs (112b) may be located on the lower portion of the second electrode uncoated portion (112a) and may be arranged to be spaced apart from each other in one direction before winding. The plurality of second electrode tabs (112b) may not be provided at the winding end. A plurality of second electrode tabs (112b) can be formed on the second electrode non-conductive portion (112a) by laser notching, ultrasonic cutting, or punching. Such a plurality of second electrode tabs (112b) can protrude further downward in the electrode assembly (110) compared to the first electrode (111) and the separator (113).

[0068] The electrode assembly (110) may have a first electrode tab (111b) that protrudes upward, and a second electrode tab (112b) that protrudes downward. The first electrode tab (111b) and the second electrode tab (112b) may be bent toward the core. That is, a plurality of first electrode tabs (111b) and a plurality of second electrode tabs (112b) may be bent from a winding end region toward the core. At this time, the first electrode tab (111b) and the second electrode tab (112b) may not be provided in some regions of the winding end so as not to cover the core hole of the electrode assembly (110). The electrode assembly (110) may have the first electrode tab (111b) positioned on the upper surface (110a), and the second electrode tab (112b) positioned on the lower surface (110b). Additionally, the first electrode tab (111b) may have a first bending point (C1) that is bent.

[0069] The electrode assembly (110) may have a first electrode coating portion (111c) of the first electrode (111) positioned lower than the upper end of the second electrode (112). That is, the upper end of the first electrode coating portion (111c) of the first electrode (111) may be positioned lower than the upper end of the second electrode coating portion (112c) of the second electrode (112). In addition, the lower end of the first electrode uncoated portion (111a) positioned at the upper end of the first electrode (111) may be positioned lower than the upper end of the second electrode (112).

[0070] The second electrode (112) may have an insulating member (114) attached to a portion of the winding tip at the upper end, which is a portion of the winding tip. Here, the tip upper end region may be a region of 3 to 5 turns of the winding tip where the cathode expansion is greatest.

[0071] The insulating member (114) may be in the form of a tape having an adhesive on one side of a thin film. The insulating member (114) may be attached to the upper end region of the tip of the second electrode (112) by the adhesive. The insulating member (114) may be attached to the upper end region of the tip of the second electrode (112) where the second electrode coating portion (112c) is located.

[0072] The insulating member (114) can be attached to one side of the second electrode (112) and the other side, which is the opposite side of the one side. That is, the insulating member (114) can be attached to both sides of the upper end region of the second electrode (112). The upper part of the insulating member (114) can protrude higher than the upper end of the second electrode (112). That is, the lower part of the insulating member (114) can be attached to each side of the second electrode (112), and the upper part can extend from the two sides of the second electrode (112) so that the opposite adhesives can be attached to each other. The upper end region of the second electrode (112) can have a shape in which the upper part is wrapped by the insulating member (114).

[0073] The insulating member (114) may have an upper end positioned lower than the first bending point (C1) of the first electrode tab (111b), and a lower end positioned higher than the first electrode coating portion (111c) of the first electrode (111). That is, in the wound electrode assembly (110), it is preferable that the insulating member (114) overlap the first electrode uncoated portion (111a) of the first electrode (111), but not overlap the first electrode coating portion (111c). When the insulating member (114) overlaps the first electrode coating portion (111c) of the first electrode (111), a capacity loss may occur due to an increase in the size of the electrode assembly (110). That is, the insulating member (114) may be attached to the second electrode (112) that overlaps the first electrode uncoated portion (111a) of the first electrode (111).

[0074] Such an insulating member (114) can prevent a short circuit with the first collector plate (130) even if the second electrode (112) in the electrode assembly (110) undergoes charging and discharging and protrudes upward. For example, the electrode assembly (110) can prevent the insulating member (114) from contacting the first collector plate (130) even if the second electrode active material of the second electrode (112) expands at the tip of the electrode assembly (110). In addition, when winding the electrode assembly (110), even if the second electrode (112) protrudes upward at the core, the insulating member (114) can prevent contact with the first collector plate (130).

[0075] FIG. 5 is another example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in FIG. 2. In addition, FIG. 6 is an exploded view illustrating the first electrode (111) and the second electrode (112) before the electrode assembly of FIG. 5 is wound. Hereinafter, the structure of the electrode assembly (110) in the secondary battery (100) will be described with reference to FIGS. 5 and 6. Here, the electrode assembly (110) may be the same as the electrode assembly (110) illustrated in FIGS. 3 and 4 except for the position where the insulating member (114A) is attached. The insulating member (114A) may be in the form of a tape having an adhesive on one surface of a thin film.

[0076] The insulating member (114A) can be attached so as to cover the upper portion of the second electrode (112). That is, the insulating member (114A) can be attached so as to cover not only the winding tip of the second electrode (112), but also the entire upper portion.

[0077] The insulating member (114A) may be in the form of a tape having an adhesive on one side of a thin film. The insulating member (114A) may be attached to the upper end region of the tip of the second electrode (112) by the adhesive. The second electrode (112) may have the insulating member (114) attached to the upper end region of the tip where the second electrode coating portion (112c) is located.

[0078] The insulating member (114A) may be attached to both sides of the upper portion of the second electrode (112). The upper portion of the insulating member (114A) may protrude further upward than the upper portion of the second electrode (112). That is, the lower portion of the insulating member (114A) may be attached to each side of the second electrode (112), and the upper portion may extend upward from both sides of the second electrode (112) so that the facing adhesives may be attached to each other. The second electrode (112) may have a form in which the upper portion is wrapped by the insulating member (114A).

[0079] The insulating member (114A) may have an upper end positioned lower than the bending point (C1) of the first electrode tab (111b), and a lower end positioned higher than the first electrode coating portion (111c) of the first electrode (111). That is, in the wound electrode assembly (110), it is preferable that the insulating member (114) overlap the first electrode non-coated portion (111a) of the first electrode (111), but not overlap the first electrode coating portion (111c). When the insulating member (114) overlaps the first electrode coating portion (111c) of the first electrode (111), a capacity loss may occur due to an increase in the size of the electrode assembly (110). That is, the insulating member (114) may be attached to the second electrode (112) that overlaps the first electrode non-coated portion (111a) of the first electrode (111).

[0080] FIG. 7 is another example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in FIG. 2. In addition, FIG. 8 is an exploded view showing the first electrode (111) and the second electrode (112) before the electrode assembly of FIG. 7 is wound. In addition, FIG. 9 is an enlarged view showing part A of FIG. 7. Hereinafter, the structure of the electrode assembly (110) in the secondary battery (100) will be described with reference to FIGS. 7 to 9. Here, the electrode assembly (110) may be the same as the electrode assembly (110) illustrated in FIGS. 3 and 4, except for the position where the insulating member (114B) is attached. The insulating member (114B) may be in the form of a tape having an adhesive on one surface of a thin film.

[0081] The insulating member (114B) may be attached to cover the upper end of the winding tip of the first electrode (111). That is, the insulating member (114B) may be attached to cover the first electrode uncoated portion (111a) of the winding tip where the first electrode tab (111b) is not formed at the upper end of the first electrode (111). The insulating member (114B) may be attached to cover the upper end of the first electrode uncoated portion (111a) of the winding tip. Here, the upper end of the winding tip of the first electrode (111) to which the insulating member (114B) is attached may be referred to as a tip upper region. The insulating member (114B) may not cover the first electrode coating portion (111c) and may not overlap with it.

[0082] The insulating member (114B) may be in the form of a tape having an adhesive on one side of a thin film. The insulating member (114B) may be attached to both sides of the upper end region of the first electrode (111). The upper part of the insulating member (114B) may protrude further upward than the upper end of the first electrode (111). That is, the lower first region (1141B) of the insulating member (114B) may be attached to both sides of the first electrode uncoated region (111a) of the first electrode (111), and the second region (1142B) located above the first region (1141B) may extend upward from both sides of the first electrode (111) so that the facing adhesives may be attached to each other. The first electrode (111) may have a form in which the upper end region of the front end is wrapped by the insulating member (114B).

[0083] The insulating member (114B) may have a second region (1142B) that protrudes further than the upper end of the separator (113). In addition, the insulating member (114B) may have a second region (1142B) that protrudes less than the upper end of the first electrode tab (111b). The insulating member (114B) may include a folded portion that is folded toward the center of the winding in the second region (1142B) that protrudes further than the separator (113). In such an insulating member (114B), the second region (1142B) may be positioned on the upper side of the separator (113) and the second electrode (112) by the folded portion of the second region (1142B). The insulating member (114B) can be interposed between the second electrode (112) of the electrode assembly (110) and the first collector plate (130) in the second region (1142B). Therefore, the insulating member (114B) can prevent a short circuit with the first collector plate (130) even when the second electrode (112) expands and protrudes upward in the electrode assembly (110) in which charging and discharging are performed. In addition, when winding the electrode assembly (110), the insulating member (114B) can prevent contact with the first collector plate (130) even when the second electrode (112) protrudes upward from the core.

[0084] In addition, the insulating member (114B) may not be provided at the upper end of the first electrode (111) closest to the core. That is, the insulating member (114C) may not be provided at the first turn of the winding tip of the first electrode (111). The electrode assembly (110) is positioned on the separator (113) on the core, and the first electrode (111), the separator (113), and the second electrode (112) may be sequentially arranged in an outward direction from the separator (113). That is, since there is no second electrode (112) closer to the core than the first electrode (111) closest to the core, attachment of the insulating member (114B) may only result in an unnecessary increase in volume.

[0085] Fig. 10 is another example of an enlarged view of the upper part of the electrode assembly in the secondary battery illustrated in Fig. 2. In addition, Fig. 11 is an enlarged view of part B of Fig. 10. Hereinafter, with reference to Figs. 10 and 11, the structure of the electrode assembly (110) in the secondary battery (100) will be described. Here, the electrode assembly (110) may be the same as the electrode assembly (110) illustrated in Figs. 3 and 4, except for the position where the insulating member (114C) is attached.

[0086] Here, the first electrode (111) and the second electrode (112) are intended to refer to the surface located on the left side as the first surface and the surface located on the right side as the second surface in FIG. 10. A separator (113) may be interposed between the first electrode (111) and the second electrode (112). The separator (113) may include a first separator (1131) interposed between the first surface of the first electrode (111) and the second surface of the second electrode (112), and a second separator (1132) interposed between the second surface of the first electrode (111) and the first surface of the second electrode (112). The first separator (1131) may have a first surface facing the first electrode (111) and a second surface facing the second electrode (112). In addition, the second separator (1132) may have a first surface facing the second electrode (112) and a second surface facing the second electrode (112). The first separator (1131) and the second separator (1132) may protrude further upwards than the second electrode (112). Therefore, the upper end of the second surface of the first separator (1131) may face the upper end of the first surface of the second separator (1132). Of course, the second electrode (112) may be interposed between the second surface of the first separator (1131) and the first surface of the second separator (1132). In addition, the first electrode (111) may be interposed between the first surface of the first separator (1131) and the second surface of the second separator (1132).

[0087] The insulating member (114C) may be attached to the upper portion of the second surface of the first separator (1131) and / or the upper portion of the first surface of the second separator (1132). Here, the insulating member (114C) may be a double-sided tape having an adhesive on both sides. By the insulating member (114C), the upper portion of the second surface of the first separator (1131) may be adhered to the upper portion of the first surface of the second separator (1132). For example, the insulating member (114C) may be provided only on the upper portion of the second surface of the first separator (1131). In this case, that is, by the adhesion of the insulating member (114C), the upper portion of the first separator (1131) and the upper portion of the second separator (1132) may cover the upper portion of the second electrode (112). Of course, the insulating member (114C) may be provided only on the upper part of the first surface of the second separator (1132), or may be provided on both the upper part of the second surface of the first separator (1131) and the upper part of the first surface of the second separator (1132).

[0088] Although such an insulating member (114C) is shown as being located at the upper end of the separator (113) in FIGS. 10 and 11, only the upper end region, which is the upper end of the winding end of the separator (113), may be provided.

[0089] As another example, instead of the double-sided tape-type insulating member (114C), an adhesive-type insulating member may be provided on the upper portion of the second surface of the first separator (1131) or the upper portion of the first surface of the second separator (1132). The adhesive-type insulating member (114C) may be applied to the upper portion of the second surface of the first separator (1131) or the upper portion of the first surface of the second separator (1132) before winding. That is, the upper portion of the first separator (1131) and the upper portion of the second separator (1132) may be bonded together using an adhesive.

[0090] Accordingly, the insulating member (114C) can prevent the second electrode (112) from being short-circuited with the first collector plate (130) even if it expands and protrudes upward in the electrode assembly (110) in which charging and discharging are performed. In addition, when winding the electrode assembly (110), even if the second electrode (112) protrudes upward from the core, it can be prevented from coming into contact with the first collector plate (130) by the insulating member (114C).

[0091] Additionally, a compound capable of reversible intercalation and deintercalation of lithium (a lithiated intercalation compound) may be used as the positive electrode active material. Specifically, one or more of a composite oxide of lithium and a metal selected from cobalt, manganese, nickel, and combinations thereof may be used.

[0092] The above composite oxide may be a lithium transition metal composite oxide, and specific examples thereof include lithium nickel-based oxide, lithium cobalt-based oxide, lithium manganese-based oxide, lithium iron phosphate-based compound, cobalt-free nickel-manganese-based oxide, or a combination thereof.

[0093] As an example, a compound represented by any one of the following chemical formulas may be used. LiaA1-bXbO2-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaMn2-bXbO4-cDc(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); LiaNi1-b-cCobXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNi1-b-cMnbXcO2-αDα(0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); LiaNibCocL1dGeO2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, 0≤e≤0.1); LiaNiGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaCoGbO2(0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-bGbO2 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn2GbO4 (0.90≤a≤1.8, 0.001≤b≤0.1); LiaMn1-gGgPO4(0.90≤a≤1.8, 0≤g≤0.5); Li(3-f)Fe2(PO4)3(0≤f≤2); LiaFePO4(0.90≤a≤1.8).

[0094] In the chemical formula, A is Ni, Co, Mn, or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, a rare earth element, or a combination thereof; D is O, F, S, P, or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V, or a combination thereof; and L1 is Mn, Al, or a combination thereof.

[0095] A positive electrode for a lithium secondary battery may include a current collector and a positive electrode active material layer formed on the current collector. The positive electrode active material layer includes a positive electrode active material and may further include a binder and / or a conductive material.

[0096] The content of the positive electrode active material may be 90 wt% to 99.5 wt% with respect to 100 wt% of the positive electrode active material layer, and the contents of the binder and conductive material may be 0.5 wt% to 5 wt%, respectively, with respect to 100 wt% of the positive electrode active material layer.

[0097] Al may be used as the above current collector, but is not limited thereto.

[0098] The negative electrode active material includes a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0099] The material capable of reversibly intercalating / deintercalating the lithium ions may include a carbon-based negative electrode active material, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of the crystalline carbon include graphite such as natural graphite or artificial graphite, and examples of the amorphous carbon include soft carbon or hard carbon, mesophase pitch carbide, calcined coke, and the like.

[0100] As the material capable of doping and dedoping the lithium, a Si-based negative electrode active material or a Sn-based negative electrode active material can be used. The Si-based negative electrode active material can be silicon, a silicon-carbon composite, SiOx (0 < x < 2), a Si-based alloy, or a combination thereof.

[0101] The above silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles and amorphous carbon coated on the surface of the silicon particles.

[0102] The silicon-carbon composite may further comprise crystalline carbon. For example, the silicon-carbon composite may comprise a core comprising crystalline carbon and silicon particles and an amorphous carbon coating layer positioned on the surface of the core.

[0103] A negative electrode for a lithium secondary battery includes a current collector and a negative electrode active material layer positioned on the current collector. The negative electrode active material layer includes a negative electrode active material and may further include a binder and / or a conductive material.

[0104] For example, the negative electrode active material layer may include 90 to 99 wt% of the negative electrode active material, 0.5 to 5 wt% of the binder, and 0 to 5 wt% of the conductive material.

[0105] The above binder may be a non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0106] The negative electrode current collector may be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, a polymer substrate coated with a conductive metal, and a combination thereof.

[0107] An electrolyte for a lithium secondary battery contains a non-aqueous organic solvent and a lithium salt.

[0108] The above non-aqueous organic solvent acts as a medium through which ions involved in the electrochemical reaction of the battery can move.

[0109] The above non-aqueous organic solvent may be a carbonate-based, ester-based, ether-based, ketone-based, or alcohol-based solvent, an aprotic solvent, or a combination thereof, and may be used alone or in combination of two or more thereof.

[0110] Additionally, when using a carbonate solvent, a mixture of cyclic carbonate and chain carbonate can be used.

[0111] Depending on the type of lithium secondary battery, a separator may be present between the positive and negative electrodes. Such separators may be polyethylene, polypropylene, polyvinylidene fluoride, or a multilayer film comprising two or more layers of these.

[0112] The above separator may include a porous substrate and a coating layer comprising an organic material, an inorganic material, or a combination thereof, positioned on one or both sides of the porous substrate.

[0113] The above organic material may include a polyvinylidene fluoride-based antibody or a (meth)acrylic polymer.

[0114] The above inorganic material may include inorganic particles selected from, but not limited to, Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite, and combinations thereof.

[0115] The organic and inorganic substances may be mixed and present in one coating layer, or a coating layer including an organic substance and a coating layer including an inorganic substance may be present in a laminated form.

[0116] Although the present invention has been described above with reference to limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical idea of ​​the present invention and the equivalent scope of the patent claims to be described below by a person having ordinary skill in the art to which the present invention pertains.

Claims

1. An electrode assembly having a first electrode, a separator, and a second electrode; A case in which the electrode assembly is accommodated and the lower part is open; A terminal electrically connected to the first electrode of the electrode assembly, penetrating the upper part of the case and exposed to the outside of the case; A first current collector plate interposed between the upper surface of the electrode assembly and the case, electrically connecting the first electrode plate and the terminal; and Includes a cap plate that seals the lower part of the case, A secondary battery wherein the electrode assembly includes an insulating member attached to one of the upper portion of the first electrode, the upper portion of the separator, and the upper portion of the second electrode.

2. In paragraph 1, A secondary battery including a first electrode coated portion coated with a first electrode active material on a first substrate in the form of a sheet, and a first electrode uncoated portion not coated with a first electrode active material on the upper portion of the first substrate.

3. In paragraph 2, A secondary battery in which the insulating member is in the form of a tape attached to cover the upper part of the first electrode non-conductive portion.

4. In paragraph 3, The above insulating member is attached to each of the two sides of the first electrode, Each insulating member has a first region, which is the lower part, attached to both sides of the first electrode non-conductive part, A secondary battery in which a second region located on the upper side of the first region extends upward from both sides of the first electrode non-conductive portion and is attached to opposite adhesives.

5. In paragraph 4, A secondary battery in which the insulating member is bent in the direction of the core, with the second region protruding further than the upper end of the separator.

6. In paragraph 4, The above insulating member is a secondary battery in which the second region is interposed between the second electrode of the electrode assembly and the first current collector plate.

7. In paragraph 3, The above insulating material A secondary battery not attached to the upper part of the first electrode closest to the above-mentioned core.

8. In paragraph 2, The first electrode non-conductive portion includes a plurality of first electrode tabs spaced apart from each other at the upper end and protruding upward from the second electrode and the separator, A secondary battery having a first bending point in which the first electrode tab is bent in the direction of the winding core.

9. In paragraph 8, A secondary battery in which the insulating member is attached to cover the upper end of the winding tip of the first electrode non-conductive portion in which the first electrode tab is not provided.

10. In paragraph 8, A secondary battery in which the insulating member is in the form of a tape attached to cover the upper part of the second electrode.

11. In paragraph 10, The above insulating member is attached to each of the two sides of the second electrode, A secondary battery in which the lower portion is attached to each of the two sides of the second electrode, and the lower portion extends upward from the two sides of the second electrode and protrudes further than the upper end of the second electrode, and the adhesives are attached to each other in opposite directions.

12. In paragraph 11, The upper end of the above insulating member is positioned lower than the first bending point of the first electrode tab, A secondary battery in which the lower portion is positioned above the first electrode coating portion of the first electrode.

13. In paragraph 11, A secondary battery in which the insulating member overlaps the first electrode non-conductive portion.

14. In paragraph 11, A secondary battery in which the insulating member is attached to cover the upper end of the winding tip of the second electrode.

15. In paragraph 11, A secondary battery in which the insulating member is attached so as to cover the entire upper portion of the second electrode.

16. In paragraph 1, The above separator A first separator interposed between the first surface of the first electrode and the second surface of the second electrode; and A second separator is included between the second surface of the first electrode and the first surface of the first electrode, The first separator includes a first surface opposite the first surface of the first electrode and a second surface opposite the second surface of the second electrode, A secondary battery wherein the second separator includes a first surface facing the first surface of the second electrode and a second surface facing the second surface of the first electrode.

17. In paragraph 16, A secondary battery in which the insulating member bonds between the upper part of the second surface of the first separator facing the second electrode and the upper part of the first surface of the second separator.

18. In paragraph 17, A secondary battery in which the insulating member is attached between the upper ends of the winding ends of the first separator and the second separator.

19. In paragraph 17, The above insulating material is a secondary battery made of double-sided tape or adhesive.

20. In paragraph 17, A secondary battery in which the upper part of the first separator and the upper part of the second separator are bonded to cover the upper part of the second electrode.

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