Secondary battery

Abstract

A secondary battery according to an exemplary embodiment of the present disclosure includes: a first electrode assembly including a first electrode tab including a plurality of 1-1 uncoated portions bent in a first direction, and a first auxiliary electrode tab protruding from the same surface as the first electrode tab; a second electrode assembly including a second electrode tab including a plurality of 2-1 uncoated portions stacked on the first electrode assembly in the first direction and bent in directions opposite to the first direction, and a second auxiliary electrode tab protruding from the same surface as the second electrode tab; and a collector plate integrally covering the first electrode tab and the second electrode tab and electrically connected to the first electrode tab and the second electrode tab, the first electrode tab being bent to contact the second auxiliary electrode tab, and the second electrode tab being bent to contact the first auxiliary electrode tab.

Description

Technical Field

[0001] The disclosure of this application relates to a secondary battery. Background Technology

[0002] Rechargeable batteries are batteries that can be repeatedly charged and discharged. With the development of the information communication and display industries, they are widely used as power sources for portable electronic communication devices such as cameras, mobile phones, and laptops. Furthermore, battery modules or battery packs incorporating rechargeable batteries are currently being developed and applied as power sources for environmentally friendly vehicles.

[0003] A secondary battery may include an electrode assembly having a positive electrode, a negative electrode, and a separator, as well as an electrolyte impregnating the electrode assembly. The secondary battery may further include an outer casing material housing the electrode assembly and the electrolyte.

[0004] For example, the electrode assembly can be manufactured in a jelly roll form by winding or folding the diaphragm, or in a stacked form by stacking the diaphragms.

[0005] A current-carrying plate can be disposed between the uncoated portion of the electrode (e.g., electrode tab) and the terminal. For example, the current-carrying plate can be joined to the uncoated portion after being bent twice, or, with the uncoated portion folded, the flat current-carrying plate can be joined to the folded surface of the uncoated portion. The flat current-carrying plate occupies a relatively small volume, thus increasing the energy density per unit volume of the secondary battery.

[0006] Recently, a method for welding multiple uncoated sections and a current collector plate in a single operation is being developed. However, since at least a portion of the multiple uncoated sections protrudes outward from the current collector plate, this may reduce manufacturability. Summary of the Invention

[0007] (a) Technical problems to be solved

[0008] According to one aspect of this disclosure, a secondary battery with improved drive reliability and manufacturability can be provided.

[0009] (II) Technical Solution

[0010] A secondary battery according to an exemplary embodiment of the present disclosure includes: a first electrode assembly, the first electrode assembly including a first electrode tab and a first auxiliary electrode tab protruding from the same surface as the first electrode tab, the first electrode tab including a plurality of first-1 uncoated portions respectively bent in a first direction; a second electrode assembly, the second electrode assembly including a second electrode tab and a second auxiliary electrode tab protruding from the same surface as the second electrode tab, the second electrode tab including a plurality of second-1 uncoated portions stacked on the first electrode assembly along the first direction and respectively bent in the opposite direction to the first direction; and a current collector plate, which integrally covers the first electrode tab and the second electrode tab and is electrically connected to the first electrode tab and the second electrode tab, the first electrode tab being bent in the first direction to contact the second auxiliary electrode tab, and the second electrode tab being bent in the opposite direction to the first direction to contact the first auxiliary electrode tab.

[0011] In some embodiments, the first electrode tab and the second electrode tab may not be disposed on the same line in the first direction, and the first auxiliary electrode tab and the second auxiliary electrode tab may not be disposed on the same line in the first direction.

[0012] In some embodiments, the first electrode tab and the second auxiliary electrode tab may be arranged on the same line in the first direction.

[0013] In some embodiments, the first electrode tab may be supported by one end of the second auxiliary electrode tab, and the second electrode tab may be supported by one end of the first auxiliary electrode tab.

[0014] In some embodiments, the first auxiliary electrode tab may include a plurality of unbent first-second uncoated portions, and the second auxiliary electrode tab may include a plurality of unbent second-second uncoated portions.

[0015] In some embodiments, the first electrode tab and the second electrode tab may be opposite each other in a first diagonal direction that is inclined relative to the first direction.

[0016] In some embodiments, the length of each of the plurality of first-1 uncoated portions and the plurality of second-1 uncoated portions in the first direction may be less than 0.5 times the width of the current collector.

[0017] In some embodiments, the ratio of the length of the first electrode tab in the first direction to the length of the second electrode tab in the first direction may be 0.5 to 1.5.

[0018] In some embodiments, the number of the plurality of uncoated portions 1-1 included in the first electrode tab may be 5 to 100, and the number of the plurality of uncoated portions 2-1 included in the second electrode tab may be 5 to 100.

[0019] In some embodiments, the width direction of the first electrode assembly and the width direction of the second electrode assembly can be the first direction, the length direction of the first electrode assembly and the length direction of the second electrode assembly can be the second direction, the height direction of the first electrode assembly and the height direction of the second electrode assembly can be the third direction, the first electrode tab and the first auxiliary electrode tab can be separated in the third direction, and the second electrode tab and the second auxiliary electrode tab can be separated in the third direction.

[0020] In some embodiments, the width direction of the first electrode assembly and the width direction of the second electrode assembly can be the first direction, the length direction of the first electrode assembly and the length direction of the second electrode assembly can be the second direction, the height direction of the first electrode assembly and the height direction of the second electrode assembly can be the third direction, the shortest distance between the first electrode tab and the second electrode tab can be less than or equal to the length of the third direction of the first electrode tab, and the shortest distance can be less than or equal to the length of the third direction of the second electrode tab.

[0021] In some embodiments, the first electrode tab may protrude from one side of the first electrode assembly, the second electrode tab may protrude from one side of the second electrode assembly, the first electrode assembly may further include a third electrode tab, the third electrode tab including a plurality of third-1 uncoated portions protruding from the other side of the first electrode assembly and bending in the first direction, and the second electrode assembly may further include a fourth electrode tab, the fourth electrode tab including a plurality of fourth-1 uncoated portions protruding from the other side of the second electrode assembly and bending in the opposite direction to the first direction.

[0022] In some embodiments, the first electrode assembly may further include a third auxiliary electrode tab protruding from the same surface as the third electrode tab and including a plurality of third-second uncoated portions, and the second electrode assembly may further include a fourth auxiliary electrode tab protruding from the same surface as the fourth electrode tab and including a plurality of fourth-second uncoated portions.

[0023] In some embodiments, the first electrode tab and the third auxiliary electrode tab may be arranged on the same line in a second direction perpendicular to the first direction, the third electrode tab and the first auxiliary electrode tab may be arranged on the same line in the second direction, the second electrode tab and the fourth auxiliary electrode tab may be arranged on the same line in the second direction, and the fourth electrode tab and the second auxiliary electrode tab may be arranged on the same line in the second direction.

[0024] In some embodiments, the first electrode tab and the second electrode tab may be opposite each other in a first diagonal direction inclined relative to the first direction, and the third electrode tab and the fourth electrode tab may be opposite each other in a second diagonal direction inclined relative to the first direction in a direction opposite to the first diagonal direction.

[0025] In some embodiments, the first electrode tab and the third electrode tab may be arranged on the same line in a second direction perpendicular to the first direction, the first auxiliary electrode tab and the third auxiliary electrode tab may be arranged on the same line in the second direction, the second electrode tab and the fourth electrode tab may be arranged on the same line in the second direction, and the second auxiliary electrode tab and the fourth auxiliary electrode tab may be arranged on the same line in the second direction.

[0026] In some embodiments, the current collector may include a welded portion formed by welding the first electrode tab and the second electrode tab to the current collector.

[0027] In some embodiments, the welding portion may be disposed on the surface of the current collector adjacent to the first electrode assembly and the second electrode assembly.

[0028] In some embodiments, the secondary battery may further include: a housing for accommodating the first electrode assembly and the second electrode assembly; a cover for sealing the housing; and electrode terminals for engaging with the cover and being electrically connected to the electrode tabs.

[0029] (III) Beneficial Effects

[0030] According to one embodiment of this disclosure, the process can be simplified.

[0031] According to one embodiment of this disclosure, the processability and structural stability of secondary batteries can be improved.

[0032] According to one embodiment of this disclosure, heat generation and damage to the secondary battery can be suppressed.

[0033] The secondary battery disclosed herein can be widely used in electric vehicles, battery charging stations, and other green technology fields such as solar power generation and wind power generation that utilize batteries. Furthermore, the secondary battery disclosed herein can be used in eco-friendly electric vehicles and hybrid vehicles to prevent climate change by suppressing air pollution and greenhouse gas emissions. Attached Figure Description

[0034] Figure 1 This is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment.

[0035] Figure 2 This is a reference diagram used to illustrate the first diagonal direction.

[0036] Figure 3 This is a schematic exploded perspective view of an electrode assembly according to an exemplary embodiment.

[0037] Figure 4 This is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment.

[0038] Figure 5 This is a reference diagram used to illustrate the second diagonal direction.

[0039] Figure 6 This is a schematic perspective view illustrating a first electrode assembly and a second electrode assembly according to an exemplary embodiment.

[0040] Figure 7 This is a schematic perspective view illustrating an electrode assembly and a current collector according to an exemplary embodiment.

[0041] Figure 8 It is along Figure 7 A schematic cross-sectional view observed along line A-A'.

[0042] Figure 9 It is along Figure 7 A schematic cross-sectional view observed along the B-B' line.

[0043] Explanation of reference numerals in the attached figures:

[0044] 100: First electrode assembly; 102: First positive electrode

[0045] 104: First negative electrode; 105: First diaphragm

[0046] 110: First current collector; 112: First coating section

[0047] 115: First active material layer; 120: First electrode tab.

[0048] 122: Uncoated portion 1-1; 200: Second electrode assembly

[0049] 202: Second positive electrode; 204: Second negative electrode

[0050] 205: Second diaphragm; 210: Second current collector.

[0051] 215: Second active material layer; 220: Second electrode tab.

[0052] 222: Uncoated part 2-1; 300: Current collector

[0053] 310: Welding section; 400: Cover plate

[0054] 410: Cover; 420: Electrode terminal

[0055] 430: Vent port; 440: Injection port

[0056] 500: Housing 510: Receiving part Detailed Implementation

[0057] Embodiments of this disclosure provide a secondary battery.

[0058] The embodiments of this disclosure will now be described in detail with reference to the accompanying drawings. However, these are merely examples, and this disclosure is not limited to the specific implementations illustrated herein.

[0059] The terms “upper surface,” “side,” “one side,” “the other side,” “one side of the side,” and “the other side” used in this specification are used in a relative sense to distinguish the positions between components, and do not specify absolute positions.

[0060] The term "first direction" as used in this specification may refer to the direction in which the first electrode tab 120 is bent. The first direction may refer to the direction in which the first electrode assembly 100 and the second electrode assembly 200 are stacked. The first direction may refer to the width direction of the first electrode assembly 100 and / or the second electrode assembly 200. Figure 1 as well as Figures 3 to 7 The first direction in the middle.

[0061] The term "second direction" as used in this specification may refer to the longitudinal direction of the first electrode assembly 100 and / or the second electrode assembly 200. The second direction may refer to the direction from one side of the first electrode assembly 100 and / or the second electrode assembly 200 toward the other side. Figure 1 as well as Figures 3 to 7 The second direction in.

[0062] The term "third orientation" as used in this specification may refer to the height direction of the first electrode assembly 100 and / or the second electrode assembly 200. The third orientation may represent... Figure 1 as well as Figures 3 to 7 The third direction in the equation. The third direction can represent a direction perpendicular to both the first direction and the second direction.

[0063] Figure 1 This is an exploded perspective view of a secondary battery according to an exemplary embodiment.

[0064] Reference Figure 1 The secondary battery may include a first electrode assembly 100 and a second electrode assembly 200.

[0065] The first electrode assembly 100 and the second electrode assembly 200 may be disposed along a first direction. For example, the second electrode assembly 200 may be stacked on the first electrode assembly 100 along the first direction. In one embodiment, the second electrode assembly 200 may be directly disposed on the first electrode assembly 100.

[0066] For example, the first electrode assembly 100 and the second electrode assembly 200 may be combined, fastened or assembled and provided as a single battery unit.

[0067] In an exemplary embodiment, the first electrode assembly 100 may include a first electrode tab 120, the first electrode tab 120 including a plurality of first-first uncoated portions 122 respectively bent in the first direction. The second electrode assembly 200 may include a second electrode tab 220, the second electrode tab 220 including a plurality of second-first uncoated portions 222 respectively bent in the opposite direction to the first direction.

[0068] In an exemplary embodiment, the first electrode assembly 100 may include a first auxiliary electrode tab 125, which includes a plurality of unbent first-second uncoated portions 124 and protrudes from the same surface as the first electrode tab 120. The second electrode assembly 200 may include a second auxiliary electrode tab 225, which includes a plurality of unbent second-second uncoated portions 224 and protrudes from the same surface as the second electrode tab 220.

[0069] In an exemplary embodiment, the first electrode tab 120 can be bent in the first direction to contact the second auxiliary electrode tab 225, and the second electrode tab 220 can be bent in the opposite direction to the first direction to contact the first auxiliary electrode tab 125. Therefore, the welding stability of the electrode tabs 120 and 220 and the current collector 300 can be improved, and the structural stability of the secondary battery can be further improved.

[0070] In some embodiments, the first electrode tab 120 may be supported by one end of the second auxiliary electrode tab 225, and the second electrode tab 220 may be supported by one end of the first auxiliary electrode tab 125. For example, the first electrode tab 120 may be bent in a first direction and extend toward the second electrode assembly 200, and the extended portion may be supported by the second auxiliary electrode tab 225. For example, the second electrode tab 220 may be bent in the opposite direction to the first direction and extend toward the first electrode assembly 100, and the extended portion may be supported by the first auxiliary electrode tab 125. Therefore, the manufacturability of the secondary battery can be further improved, and its stability can be further enhanced.

[0071] In some embodiments, the first electrode tab 120 and the first auxiliary electrode tab 125 may be spaced apart upwards from the third party. The second electrode tab 220 and the second auxiliary electrode tab 225 may be spaced apart upwards from the third party.

[0072] For example, the first electrode assembly 100 and the second electrode assembly 200 may each include a plurality of electrodes stacked repeatedly and a diaphragm inserted between the electrodes.

[0073] Each of the plurality of electrodes may include an uncoated portion. For example, the electrodes included in the first electrode assembly 100 may each include a first-1 uncoated portion 122 and a first-2 uncoated portion 124, and the electrodes included in the second electrode assembly 200 may each include a second-1 uncoated portion 222 and a second-2 uncoated portion 224.

[0074] For example, the first electrode tab 120 may include a collection of a plurality of first-1 uncoated portions 122 and a collection of a plurality of first-2 uncoated portions 124, and the second electrode tab 220 may include a collection of a plurality of second-1 uncoated portions 222 and a collection of a plurality of second-2 uncoated portions 224.

[0075] In one embodiment, the plurality of first-1 uncoated portions 122 may not be individually joined or crimped together. For example, the plurality of first-2 uncoated portions 124 may not be individually joined or crimped together.

[0076] In one embodiment, the plurality of second-first uncoated portions 222 may not be individually joined or crimped together. For example, the plurality of second-second uncoated portions 224 may not be individually joined or crimped together.

[0077] In some embodiments, the number of the plurality of first-1 uncoated portions 122 included in the first electrode tab 120 can be 5 to 100, or 10 to 50. The number of the plurality of second-1 uncoated portions 222 included in the second electrode tab 220 can be 5 to 100, or 10 to 50. Within these ranges, space efficiency can be improved while enhancing the output characteristics of the secondary battery.

[0078] In some embodiments, the number of the plurality of first-second uncoated portions 124 included in the first auxiliary electrode tab 125 can be 5 to 100, or 10 to 50. The number of the plurality of second-second uncoated portions 224 included in the second auxiliary electrode tab 225 can be 5 to 100, or 10 to 50. Within these ranges, the bent first electrode tab 120 can be sufficiently supported by the second auxiliary electrode tab 225, and the bent second electrode tab 220 can be sufficiently supported by the first auxiliary electrode tab 125. Therefore, the stability of the welding can be further improved, and the structural stability of the secondary battery can be further improved.

[0079] In an exemplary embodiment, the first electrode tab 120 can be bent in a first direction, and the second electrode tab 220 can be bent in the opposite direction to the first direction. For example, multiple first-first uncoated portions 122 can be bent in the first direction, and multiple second-first uncoated portions 222 can be bent in the opposite direction to the first direction. Since the first electrode assembly 100 and the second electrode assembly 200 are stacked, the bent first electrode tab 120 and the second electrode tab 220 do not protrude outwards from the electrode assembly. Therefore, no additional bending process is required for the protruding portions, and the thickness of the secondary battery is reduced, thereby improving manufacturability and structural stability.

[0080] The term "opposite direction of the first direction" as used in this specification may refer to the direction in which the uncoated portion 2-1 and / or the second electrode tab 220 bends.

[0081] In an exemplary embodiment, the first electrode tab 120 and the second electrode tab 220 may not be disposed on the same line in the first direction. Therefore, it is possible to improve manufacturability and reliability while preventing the secondary battery from overheating and being damaged due to contact between the first electrode tab 120 and the second electrode tab 220.

[0082] In this disclosure, "A and B are not set on the same line in a predetermined direction" can mean "A and B are not set together on a virtual straight line extending along a predetermined direction".

[0083] In this disclosure, “A and B are arranged on the same line in a predetermined direction” can mean “A and B are arranged together on at least one straight line extending in a predetermined direction”.

[0084] In an exemplary embodiment, the first auxiliary electrode tab 125 and the second auxiliary electrode tab 225 may not be disposed on the same line in the first direction.

[0085] For example, the first electrode tab 120 and the second auxiliary electrode tab 225 can be arranged on the same line in the first direction. Therefore, the first electrode tab 120 bent in the first direction and the second electrode tab 220 bent in the opposite direction to the first direction can contact / support the second auxiliary electrode tab 225 and the first auxiliary electrode tab 125, respectively.

[0086] In some embodiments, the first electrode tab 120 and the second electrode tab 220 may be opposite each other in a first diagonal direction that is inclined relative to the first direction.

[0087] For example, the first diagonal direction can be a direction from the center of the first-1 uncoated portion 122 furthest from the second electrode assembly 200 to the center of the second-1 uncoated portion 222 furthest from the first electrode assembly 100. The center of the first-1 uncoated portion can refer to the center point of the first-1 uncoated portion in its unbent state, and the center of the second-1 uncoated portion can refer to the center point of the second-1 uncoated portion in its unbent state.

[0088] Figure 2 This is a reference diagram used to illustrate the first diagonal direction.

[0089] Reference Figure 2 The first diagonal direction can be represented as the direction extending between the first direction and the third direction on the plane formed by the first direction and the third direction.

[0090] For example, the first diagonal direction may be tilted relative to the first direction by 1° to 89°, 10° to 80°, or 30° to 60°.

[0091] Refer again Figure 1 In an exemplary embodiment, the secondary battery may include a current collector 300, which covers the first electrode tab 120 and the second electrode tab 220 and is electrically connected to the first electrode tab 120 and the second electrode tab 220.

[0092] According to one embodiment, the current collector 300 may include a plate shape. Therefore, the volume of the current collector 300 is reduced, thereby improving the capacity and energy density of the secondary battery, and the contact area between the electrode plate 300 and the electrode tabs 120, 220 is increased, thereby reducing the resistance of the secondary battery.

[0093] In one embodiment, a conductive metal plate may be provided as a current collector 300.

[0094] The connection structure between the current collector 300 and the electrode tabs 120 and 220 will be referred to below. Figure 8 and Figure 9 Please provide an explanation.

[0095] In some embodiments, the length L in the first direction of each of the plurality of first-1 uncoated portions may be less than 0.5 times the width W of the current collector 300, and the length L in the first direction of each of the plurality of second-1 uncoated portions may be less than 0.5 times the width W of the current collector 300. Within this range, the electrode tabs 120, 220 do not protrude to the outside of the electrode assemblies 100, 200, thus eliminating the need for additional bending processes and reducing the volume of the secondary battery.

[0096] According to one embodiment, the length L in the first direction of each of the plurality of first-1 uncoated portions and the plurality of second-1 uncoated portions can be 0.01 to 0.5 times the width W of the current collector 300. Therefore, the current collector 300 and the electrode tabs 120, 220 can be stably connected.

[0097] In some embodiments, the third-order lengths of the first electrode tab 120 and the first auxiliary electrode tab 125 may be less than 0.5 times or between 0.1 times and 0.4 times the third-order length of the first electrode assembly 100. Within this range, space efficiency can be improved while enhancing the output characteristics of the secondary battery.

[0098] In some embodiments, the third-order length of each of the second electrode tab 220 and the second auxiliary electrode tab 225 may be less than 0.5 times or between 0.1 times and 0.4 times the third-order length of the second electrode assembly 200. Within this range, space efficiency can be improved while enhancing the output characteristics of the secondary battery.

[0099] In some embodiments, the shortest distance D between the first electrode tab 120 and the second electrode tab 220 can be less than or equal to the third-direction length of the first electrode tab 120. Within this range, heat generation and damage caused by contact between the electrode tabs 120 and 220 can be suppressed, and the space efficiency of the secondary battery can be improved.

[0100] In some embodiments, the shortest distance D between the first electrode tab 120 and the second electrode tab 220 may be less than or equal to the third-direction length of the second electrode tab 220. Within this range, heat generation and damage caused by contact between the electrode tabs 120 and 220 can be suppressed, and the space efficiency of the secondary battery can be improved.

[0101] In some embodiments, the ratio of the length of the first electrode tab 120 in the first direction to the length of the second electrode tab 220 in the first direction can be 0.5 to 1.5, or 0.8 to 1.2. Within this range, lifetime characteristics and drive stability can be improved by preventing overcurrent in the feature portion of the secondary battery.

[0102] In one embodiment, the length of the first electrode tab 120 in the first direction may be substantially the same as the length of the second electrode tab 220 in the first direction.

[0103] In some embodiments, the lengths of the first auxiliary electrode tab 125 and the second auxiliary electrode tab 225 can be from 0.5 mm to 3 mm, respectively. Within this range, the space utilization rate of the secondary battery can be further improved while adequately supporting the second electrode tab 220 and the first electrode tab 120.

[0104] Figure 3 This is a schematic exploded perspective view of an electrode assembly according to an exemplary embodiment. For example, Figure 3 The electrode stacking structures included in the first electrode assembly 100 and the second electrode assembly 200 can be illustrated. For example, the first electrode assembly 100 and the second electrode assembly 200 may each include a jellyroll configuration in which multiple electrode stacking structures are repeatedly stacked. For example, the electrode assemblies 100 and 200 can be formed by winding, stacking, z-folding, stack-folding, etc., of the diaphragms 105 and 205.

[0105] Reference Figure 3 The electrode stack structure of the first electrode assembly 100 may include a first positive electrode 102, a first negative electrode 104, and a first diaphragm 105 inserted between the first positive electrode 102 and the first negative electrode 104.

[0106] According to an exemplary embodiment, the first positive electrode 102 and the first negative electrode 104 may be alternately and repeatedly stacked with respect to the first diaphragm 105, thereby defining the first electrode assembly 100.

[0107] The first positive electrode 102 and the first negative electrode 104 may each include a first coated portion 112, a first uncoated portion 122, and a first uncoated portion 124.

[0108] The first coated portion 112 may include a first current collector 110 and a first active material layer 115 disposed on at least one side of the first current collector 110. The first-1 uncoated portion 122 and the first-2 uncoated portion 124 may represent areas on the first current collector 110 where the first active material layer 115 is not disposed. The first-1 uncoated portion 122 and the first-2 uncoated portion 124 may extend from the first current collector 110 of the first coated portion 112 and protrude from the first coated portion 112. The first-1 uncoated portion 122 and the first-2 uncoated portion 124 may be spaced apart upwards from the first current collector 110.

[0109] In one embodiment, the first active material layer 115 may be disposed on both sides of the first current collector 110.

[0110] In some embodiments, the first positive electrode coating portion 112a and the first negative electrode coating portion 112b may overlap each other in the direction of electrode stacking. For example, a first diaphragm 105 may be inserted between the first positive electrode coating portion 112a and the first negative electrode coating portion 112b.

[0111] According to an exemplary embodiment, the first-1 positive electrode uncoated portion 122a and the first-1 negative electrode uncoated portion 122b may protrude in opposite directions to each other. The first-2 positive electrode uncoated portion 124a and the first-2 negative electrode uncoated portion 124b may protrude in opposite directions to each other. For example, the first-1 positive electrode uncoated portion 122a and the first-2 positive electrode uncoated portion 124a may protrude from the first positive electrode coated portion 112a in a direction to one side, and the first-1 negative electrode uncoated portion 122b and the first-2 negative electrode uncoated portion 124b may protrude from the first negative electrode coated portion 112b in a direction opposite to the direction to one side.

[0112] The electrode stack structure of the second electrode assembly 200 may include a second positive electrode 202, a second negative electrode 204, and a second diaphragm 205 inserted between the second positive electrode 202 and the second negative electrode 204.

[0113] According to an exemplary embodiment, the second positive electrode 202 and the second negative electrode 204 may be alternately and repeatedly stacked with respect to the second diaphragm 205, thereby defining the second electrode assembly 200.

[0114] The second positive electrode 202 and the second negative electrode 204 may each include a second coated portion 212, a second-first uncoated portion 222, and a second-second uncoated portion 224.

[0115] The second coating portion 212 may include a second current collector 210 and a second active material layer 215 disposed on at least one side of the second current collector 210. The second-first uncoated portion 222 and the second-second uncoated portion 224 may represent areas on the second current collector 210 where the second active material layer 215 is not disposed. The second-first uncoated portion 222 and the second-second uncoated portion 224 may extend from the second current collector 210 of the second coating portion 212 and protrude from the second coating portion 212. The second-first uncoated portion 222 and the second-second uncoated portion 224 may be spaced apart upwards from the second current collector 210.

[0116] In one embodiment, the second active material layer 215 may be disposed on both sides of the second current collector 210.

[0117] In some embodiments, the second positive electrode coating portion 212a and the second negative electrode coating portion 212b may overlap each other in the direction of electrode stacking. For example, a second diaphragm 205 may be inserted between the second positive electrode coating portion 212a and the second negative electrode coating portion 212b.

[0118] According to an exemplary embodiment, the second-first uncoated positive electrode portion 222a and the second-first uncoated negative electrode portion 222b may protrude in opposite directions. Similarly, the second-second uncoated positive electrode portion 224a and the second-second uncoated negative electrode portion 224b may protrude in opposite directions. For example, the second-first uncoated positive electrode portion 222a and the second-second uncoated positive electrode portion 224a may protrude from the second coated positive electrode portion 212a in a direction to one side, and the second-first uncoated negative electrode portion 222b and the second-second uncoated negative electrode portion 224b may protrude from the second coated negative electrode portion 212b in a direction opposite to that direction.

[0119] In an exemplary embodiment, the positive electrode 102, 202 may include a positive electrode current collector and a layer of positive electrode active material disposed on at least one side of the positive electrode current collector.

[0120] For example, the positive electrode current collector can contain stainless steel, nickel, aluminum, titanium, or alloys thereof. The positive electrode current collector can also contain aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver. For example, the thickness of the positive electrode current collector can be from 10 μm to 50 μm.

[0121] The positive electrode active material layer may contain a positive electrode active material. For example, the positive electrode active material may contain a compound capable of reversibly intercalating and deintercalating lithium ions.

[0122] According to an exemplary embodiment, the positive electrode active material may comprise a lithium-nickel metal oxide. The lithium-nickel metal oxide may further comprise at least one of cobalt (Co), manganese (Mn), and aluminum (Al).

[0123] In some embodiments, the positive electrode active material or the lithium-nickel metal oxide may comprise a layered structure or a crystal structure represented by the following chemical formula 1.

[0124] [Chemical Formula 1]

[0125] Li x Ni a M b O 2+z

[0126] In chemical formula 1, the values ​​can be 0.9≤x≤1.2, 0.5≤a≤0.99, 0.01≤b≤0.5, and -0.5≤z≤0.1. As mentioned above, M can contain cobalt (Co), manganese (Mn), and / or aluminum (Al).

[0127] The chemical structure represented by Formula 1 illustrates the bonding relationships contained within the layered or crystalline structure of the positive electrode active material, and does not exclude other additional elements. For example, M contains cobalt (Co) and / or manganese (Mn), and cobalt (Co) and / or manganese (Mn) can be provided together with nickel (Ni) as the main active element of the positive electrode active material. Formula 1 is provided to illustrate the bonding relationships of the said main active elements and should be understood as including relationships involving the introduction and substitution of additional elements.

[0128] In one embodiment, an auxiliary element may be further included, added together with the primary active element, to enhance the chemical stability of the positive electrode active material or the layered / crystal structure. The auxiliary element may be incorporated into the layered / crystal structure to form a bond, and it should be understood that this also includes the chemical structures represented by Formula 1.

[0129] For example, the auxiliary element may include at least one selected from sodium (Na), magnesium (Mg), calcium (Ca), yttrium (Y), titanium (Ti), hafnium (Hf), vanadium (V), niobium (Nb), tantalum (Ta), chromium (Cr), molybdenum (Mo), tungsten (W), iron (Fe), copper (Cu), silver (Ag), zinc (Zn), boron (B), aluminum (Al), gallium (Ga), carbon (C), silicon (Si), tin (Sn), strontium (Sr), barium (Ba), radium (Ra), phosphorus (P), and zirconium (Zr). For example, the auxiliary element may also be used, like aluminum (Al), together with cobalt (Co) or manganese (Mn), as an auxiliary active element that contributes to the capacity / output activity of the positive electrode active material.

[0130] For example, the positive electrode active material or the lithium-nickel metal oxide may contain a layered structure or a crystal structure represented by the following chemical formula 1-1.

[0131] [Chemical Formula 1-1]

[0132] Li x Ni a M1 b1 M2 b2 O 2+z

[0133] In chemical formula 1-1, M1 may contain cobalt (Co), manganese (Mn), and / or aluminum (Al). M2 may contain the aforementioned auxiliary elements. In chemical formula 1-1, the following values ​​may be present: 0.9≤x≤1.2, 0.6≤a≤0.99, 0.01≤b1+b2≤0.4, -0.5≤z≤0.1.

[0134] The positive electrode active material may further include coating elements or doping elements. For example, elements that are substantially the same as or similar to the auxiliary elements described above can be used as coating elements or doping elements. For example, two or more of the elements described above can be used alone or in combination as coating elements or doping elements.

[0135] The coating element or doping element may exist on the surface of the lithium-nickel metal oxide particles, or it may penetrate through the surface of the lithium-nickel metal composite oxide particles and be contained within the bonding structure represented by chemical formula 1 or chemical formula 1-1.

[0136] The positive electrode active material may comprise nickel-cobalt-manganese (NCM)-based lithium oxide. In this case, NCM-based lithium oxide with increased nickel content can be used.

[0137] Nickel (Ni) can serve as a transition metal relevant to the output and capacity of lithium secondary batteries. Therefore, as described above, by using a high-Ni composition in the positive electrode active material, a high-capacity positive electrode and a high-capacity lithium secondary battery can be provided.

[0138] However, increasing the nickel (Ni) content may relatively reduce the long-term storage stability and lifetime stability of the cathode or secondary battery, and may also increase side reactions with the electrolyte. However, according to exemplary embodiments, conductivity is maintained by including cobalt (Co), and lifetime stability and capacity retention characteristics can be improved by using manganese (Mn).

[0139] The content of nickel (Ni) in the NCM-based lithium oxide (for example, the mole fraction of nickel in the total moles of nickel, cobalt, and manganese) can be 0.5 or more, 0.6 or more, 0.7 or more, or 0.8 or more. In some embodiments, the content of nickel (Ni) can be 0.8 to 0.95, 0.82 to 0.95, 0.83 to 0.95, 0.84 to 0.95, 0.85 to 0.95, or 0.88 to 0.95.

[0140] In some embodiments, the positive electrode active material may also include a lithium cobalt oxide-based active material, a lithium manganese oxide-based active material, a lithium nickel oxide-based active material, or a lithium iron phosphate-based (LFP) active material (for example, LiFePO4).

[0141] In some embodiments, for example, the positive electrode active material may include a lithium-rich layered oxide (LLO) / over-lithiated oxide (OLO)-based active material having a chemical structure or crystal structure represented by Chemical Formula 2, a manganese-rich (Mn-rich)-based active material, a cobalt-free (Co-less)-based active material, etc. These can be used alone or in combination of two or more.

[0142] [Chemical Formula 2]

[0143] p[Li2MnO3]·(1-p)[Li q JO2]

[0144] In Chemical Formula 2, 0 < p < 1, 0.9 ≤ q ≤ 1.2, and J may include at least one element among manganese (Mn), nickel (Ni), cobalt (Co), iron (Fe), chromium (Cr), vanadium (V), copper (Cu), zinc (Zn), titanium (Ti), aluminum (Al), magnesium (Mg), and boron (B).

[0145] In an exemplary embodiment, the negative electrodes 104 and 204 may include a negative electrode current collector and a negative electrode active material layer provided on at least one surface of the negative electrode current collector.

[0146] For example, the negative electrode current collector may include a copper foil, a nickel foil, a stainless steel foil, a titanium foil, a nickel foam, a copper foam, and a polymer substrate coated with a conductive metal, etc. These can be used alone or in combination of two or more. For example, the thickness of the negative electrode current collector may be 10 μm to 50 μm.

[0147] The negative electrode active material layer may include a negative electrode active material.

[0148] For example, the negative electrode active material may contain substances capable of adsorbing and deintercalating lithium ions. For example, the negative electrode active material may use carbon-based materials such as crystalline carbon, amorphous carbon, carbon composites, and carbon fibers, as well as lithium metal, lithium alloys, silicon (Si)-containing materials, or tin (Sn)-containing materials. These can be used individually or in combination of two or more.

[0149] The amorphous carbon may include hard carbon, soft carbon, coke, mesocarbon microbeads (MCMB), and mesophase pitch-based carbon fiber (MPCF), etc.

[0150] The crystalline carbon may include graphite-based carbon such as natural graphite, artificial graphite, graphitized coke, graphitized MCMB, and graphitized MPCF.

[0151] The lithium metal may include pure lithium metal and / or lithium metal with a protective layer formed to suppress dendrite growth. In one embodiment, the lithium-containing metal layer deposited or coated on the negative electrode current collector can be used as the negative electrode active material layer. In one embodiment, the lithium thin film layer can also be used as the negative electrode active material layer.

[0152] Elements included in the lithium alloy may include aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, and indium. These may be used individually or in combination of two or more.

[0153] The silicon-containing material can provide further enhanced capacity characteristics. The silicon-containing material may include silicon (Si), SiOx (0 < x < 2), metal-doped SiOx (0 < x < 2), and silicon-carbon complexes, etc.

[0154] The metal may contain lithium and / or magnesium, and the metal-doped SiOx (0 < x < 2) may contain metal silicates.

[0155] In some embodiments, the electrode assembly may further include a conductive material.

[0156] For example, the conductive material can be added to improve the conductivity of the electrode and / or the mobility of lithium ions or electrons. For example, the conductive material may include, but is not limited to, carbon-based conductive materials such as conductive carbon, graphite, carbon black, acetylene black, Ketjen black, graphene, carbon nanotubes (CNTs), vapor-grown carbon fiber (VGCF), and carbon fibers, and / or metal-based conductive materials such as perovskite materials such as tin, tin oxide, titanium oxide, LaSrCoO3, and LaSrMnO3. These can be used alone or in combination of two or more.

[0157] In some embodiments, the membranes 105 and 205 may be configured to prevent electrical short circuits between the positive electrodes 102 and 202 and the negative electrodes 104 and 204, and to generate ion flow. For example, the thickness of the membrane may be from 10 μm to 20 μm.

[0158] For example, diaphragms 105 and 205 may include porous polymer membranes or porous nonwoven fabrics.

[0159] The porous polymer membrane may contain polyolefin-based polymers such as ethylene polymers, propylene polymers, ethylene / butene copolymers, ethylene / hexene copolymers, and ethylene / methacrylate copolymers. These can be used alone or in combination of two or more.

[0160] The porous nonwoven fabric may contain high-melting-point glass fibers, polyethylene terephthalate fibers, etc.

[0161] The diaphragms 105 and 205 may also contain ceramic-based materials. For example, inorganic particles may be coated on or dispersed within the polymer membrane to improve heat resistance.

[0162] The diaphragms 105 and 205 may have a single-layer or multi-layer structure including the polymer membrane and / or nonwoven fabric described above.

[0163] The secondary battery may include a housing 500 that houses a first electrode assembly 100 and a second electrode assembly 200. The housing 500 may be provided as at least a portion of the outer surface of the secondary battery. In one embodiment, the housing 500 may comprise metal. Therefore, impacts to the first electrode assembly 100 and the second electrode assembly 200 can be mitigated.

[0164] The housing 500 may include a receiving portion 510 that houses the first electrode assembly 100 and the second electrode assembly 200. For example, an opening may be formed on the upper surface of the housing 500, such that the housing 500 is open to the third direction upward. The first electrode assembly 100 and the second electrode assembly 200 may be housed within the receiving portion 510 through the opening.

[0165] In some embodiments, the secondary battery may include a cover plate 400 for sealing the housing 500. The cover plate 400 may be assembled onto the housing 500. For example, the opening of the cover plate 400 and the housing 500 may be assembled to seal the receiving portion 510.

[0166] For example, cover 400 may include cover 410. Cover 410 may have a plate shape. Cover 400 may be engaged, fastened or connected to housing 500 via cover 410.

[0167] For example, the cover plate 400 may include an injection hole 440. The injection hole 440 may be a hole or opening formed on the cover 410. Electrolyte can be injected into the interior of the housing 500 through the injection hole 440.

[0168] For example, the cover 400 may include a vent 430. The vent 430 may be formed to penetrate the cover 410. Through the vent 430, the space inside the housing 500 can be confined to the outside.

[0169] For example, an exhaust plate can be attached to the exhaust port 430. When the internal pressure of the housing 500 reaches or exceeds a set pressure, the exhaust plate can rupture. Therefore, gases and the like inside the housing 500 can be discharged to the outside of the housing 500, and the internal pressure of the housing 500 can be reduced.

[0170] For example, the secondary battery may include electrode terminals 420, which are coupled to a cover plate 400 and electrically connected to electrode tabs 120, 130, 220, and 230. Electrode terminals 420 may be coupled to a cover 410. For example, the cover 410 may include an opening that allows coupling with the electrode terminals 420. The opening may extend through the cover 410. Through the opening, the electrode terminals 420 may be electrically connected to a first electrode assembly 100 and a second electrode assembly 200.

[0171] Electrode terminal 420 may include a positive terminal 420a and a negative terminal 420b. The positive terminal 420a may be electrically connected to the positive terminal tab. The negative terminal 420b may be electrically connected to the negative terminal tab.

[0172] Electrode assemblies 100 and 200 can be housed together with the electrolyte within a housing 500, thereby defining a lithium secondary battery. According to an exemplary embodiment, the electrolyte can be a non-aqueous electrolyte. For example, a non-aqueous electrolyte can be injected into the housing 500 through an injection port 440 in the cover plate 400.

[0173] Non-aqueous electrolytes may contain a lithium salt as the electrolyte and an organic solvent. The lithium salt may be derived from Li... + X - This indicates that the negative ion X of the lithium salt... - It can contain F - Cl - ,Br - I - NO3 - N(CN)2 - BF4 - ClO4 - PF6 - (CF3)2PF4 - (CF3)3PF3 - (CF3)4PF2 - (CF3)5PF - (CF3)6P - CF3SO3 - CF3CF2SO3 - (CF3SO2)2N - (FSO2)2N - CF3CF2(CF3)2CO - (CF3SO2)2CH - (SF5)3C - (CF3SO2)3C - CF3(CF2)7SO3 - CF3CO2 - CH3CO2 - SCN - and (CF3CF2SO2)2N - wait.

[0174] For example, the organic solvent may include propylene carbonate (PC), ethylene carbonate (EC), butene carbonate, diethyl carbonate (DEC), dimethyl carbonate (DMC), methyl ethyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, vinylene carbonate, methyl acetate (MA), ethyl acetate (EA), n-propylacetate (n-PA), 1,1-dimethylethyl acetate (DMEA), methyl propionate (MP), ethyl propionate (EP), ethyl fluoroacetate (FEA), ethyl difluoroacetate (DFEA), ethyl trifluoroacetate (TFEA), dibutyl ether, tetraethylene glycol dimethyl ether (TEGDME), and diethylene glycol dimethyl ether. DEGDME, dimethoxyethane, tetrahydrofuran (THF), 2-methyltetrahydrofuran, ethyl alcohol, isopropyl alcohol, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, γ-butyrolactone, and propylene sulfite, etc. These can be used alone or in combination of two or more.

[0175] The non-aqueous electrode solution may further contain additives. For example, the additives may include cyclic carbonate compounds, fluorocarbonate compounds, sulfonyl lactone compounds, cyclic sulfate compounds, cyclic sulfite compounds, phosphate compounds, and borate compounds. These may be used alone or in combination of two or more.

[0176] The cyclic carbonate-based compound may include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), etc.

[0177] The fluorocarbonate-based compound may include fluoroethylenecarbonate (FEC), etc.

[0178] The sulcinolone compound may include 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, etc.

[0179] The cyclic sulfate-based compound may include 1,2-ethylene sulfate, 1,2-propylene sulfate, etc.

[0180] The cyclic sulfite-based compound may include ethylene sulfite, butene sulfite, etc.

[0181] The phosphate ester-based compound may include lithium difluorobis-oxalato phosphate, lithium difluorophosphate, etc.

[0182] The borate ester compound may include lithium bis(oxalate) borate, etc.

[0183] In some embodiments, a solid electrolyte can be used instead of the non-aqueous electrolyte described above. In this case, the lithium secondary battery can be manufactured in an all-solid-state battery form. Additionally, a solid electrolyte layer can be disposed between the positive electrodes 102, 202 and the negative electrodes 104, 204 to replace the separators 105, 205 described above.

[0184] The solid electrolyte may include a sulfide-based electrolyte. As a non-limiting example, the sulfide-based electrolyte may include Li₂S-P₂S₅, Li₂S-P₂S₅-LiCl, Li₂S-P₂S₅-LiBr, Li₂S-P₂S₅-LiCl-LiBr, Li₂S-P₂S₅-Li₂O, Li₂S-P₂S₅-Li₂O-LiI, Li₂S-SiS₂, Li₂S-SiS₂-LiI, Li₂S-SiS₂-LiBr, Li₂S-SiS₂-LiCl, Li₂S-SiS₂-B₂S₃-LiI, Li₂S-SiS₂-P₂S₅-LiI, Li₂S-B₂S₃, and Li₂S-P₂S₅-Z.m S n (m and n are positive numbers, Z is Ge, Zn, or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q (p and q are positive numbers, M is P, Si, Ge, B, Al, Ga, or In), Li7-xPS6-xCl x (0≤x≤2), Li7-xPS6-xBr x (0≤x≤2) and Li7-xPS6-xI x (0≤x≤2), etc. These can be used individually or in combination of two or more.

[0185] In one embodiment, for example, the solid electrolyte may also include oxide-based amorphous solid electrolytes such as Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, and Li2O-B2O3-ZnO.

[0186] Figure 4 This is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment. Figure 4 For ease of explanation, electrode tabs 120, 130, 220, and 230 are shown in an unbent form, but it should be interpreted that, as described above, electrode tabs 120, 130, 220, and 230 are arranged in a bent form in the secondary battery.

[0187] Reference Figure 4 The first electrode assembly 100 may include a first electrode tab 120 and a first auxiliary electrode tab 125 protruding from one side of the first electrode assembly 100, and a third electrode tab 130 and a third auxiliary electrode tab 135 protruding from the other side of the first electrode assembly 100.

[0188] The third electrode tab 130 may include a plurality of third-first uncoated portions 132, which protrude from the other side of the first electrode assembly 100 and are bent in a first direction respectively.

[0189] The third auxiliary electrode tab 135 protrudes from the same surface as the third electrode tab 130, and may include a plurality of unbent third-second uncoated portions 134.

[0190] The second electrode assembly 200 may include a second electrode tab 220 and a second auxiliary electrode tab 225 protruding from one side of the second electrode assembly 200, and a fourth electrode tab 230 and a fourth auxiliary electrode tab 235 protruding from the other side of the second electrode assembly 200.

[0191] The fourth electrode tab 230 may include a plurality of fourth-first uncoated portions 232, which protrude from the other side of the second electrode assembly 200 and bend in the opposite direction to the first direction.

[0192] The fourth auxiliary electrode tab 235 protrudes from the same surface as the fourth electrode tab 230, and may include a plurality of fourth-second uncoated portions 234.

[0193] The first electrode assembly 100 and the second electrode assembly 200 can be stacked such that one side of the first electrode assembly 100 and one side of the second electrode assembly 200 are in contact, and the other side of the first electrode assembly 100 and the other side of the second electrode assembly 200 are in contact.

[0194] In some embodiments, the first electrode tab 120 and the third electrode tab 130 may not be arranged on the same line in a second direction perpendicular to the first direction. The second electrode tab 220 and the fourth electrode tab 230 may not be arranged on the same line in the second direction.

[0195] like Figure 4 As shown, the first electrode tab 120 and the third auxiliary electrode tab 135 can be arranged on the same line in the second direction. The third electrode tab 130 and the first auxiliary electrode tab 125 can be arranged on the same line in the second direction. The second electrode tab 220 and the fourth auxiliary electrode tab 235 can be arranged on the same line in the second direction. The fourth electrode tab 230 and the second auxiliary electrode tab 225 can be arranged on the same line in the second direction.

[0196] In some embodiments, the third electrode tab 130 and the fourth electrode tab 230 may be opposite each other in a second diagonal direction that is inclined relative to the first direction in a direction opposite to the first diagonal direction. Therefore, heat generation and damage to the secondary battery caused by contact between the third electrode tab 130 and the fourth electrode tab 230 can be prevented, and manufacturability and reliability can be improved.

[0197] For example, the second diagonal direction can be a direction from the center of the third-first uncoated portion 132 furthest from the second electrode assembly 200 to the center of the fourth-first uncoated portion 232 furthest from the first electrode assembly 100. The center of the third-first uncoated portion can refer to the center point of the third-first uncoated portion in its unbent state, and the center of the fourth-first uncoated portion can refer to the center point of the fourth-first uncoated portion in its unbent state.

[0198] Figure 5 This is a reference diagram used to illustrate the second diagonal direction.

[0199] Reference Figure 5 The second diagonal direction can be represented on the plane formed by the first direction and the third direction, with the third direction as a reference, as a direction symmetrical to the first diagonal direction.

[0200] Figure 6 This is a schematic perspective view illustrating a first electrode assembly and a second electrode assembly according to an exemplary embodiment. Figure 6 For ease of explanation, electrode tabs 120, 130, 220, and 230 are shown in an unbent form, but it should be interpreted that, as described above, electrode tabs 120, 130, 220, and 230 are arranged in a bent form in the secondary battery.

[0201] like Figure 6 As shown, the first electrode tab 120 and the third electrode tab 130 of the first electrode assembly 100 can be arranged on the same line in the second direction. The first auxiliary electrode tab 125 and the third auxiliary electrode tab 135 can be arranged on the same line in the second direction. The second electrode tab 220 and the fourth electrode tab 230 of the second electrode assembly 200 can be arranged on the same line in the second direction. The second auxiliary electrode tab 225 and the fourth auxiliary electrode tab 235 can be arranged on the same line in the second direction.

[0202] In some embodiments, the second electrode tab 220 and the fourth electrode tab 230 may be opposite each other in the first diagonal direction. Therefore, it is possible to prevent the secondary battery from overheating and being damaged due to contact between the second electrode tab 220 and the fourth electrode tab 230, and to improve manufacturability and reliability.

[0203] In some embodiments, the length of each of the plurality of third-1 uncoated portions and the plurality of fourth-1 uncoated portions in the first direction may be less than 0.5 times the width of the current collector, and in one embodiment, it may be 0.01 times to 0.5 times. Therefore, the current collector 300 and the electrode tabs 130, 230 can be stably connected.

[0204] In some embodiments, the first electrode tab 120, the first auxiliary electrode tab 125, the second electrode tab 220, and the second auxiliary electrode tab 225 can be provided as positive electrode tabs, and the third electrode tab 130, the third auxiliary electrode tab 135, the fourth electrode tab 230, and the fourth auxiliary electrode tab 235 can be provided as negative electrode tabs.

[0205] For example, the first-1 positive electrode uncoated portion 122a of the first electrode assembly 100 can be provided as the first-1 uncoated portion 122, and the assembly of the first-1 uncoated portions 122 can be provided as the first electrode tab 120.

[0206] For example, the first-second positive electrode uncoated portion 124a of the first electrode assembly 100 can be provided as the first-second uncoated portion 124, and the assembly of the first-second uncoated portions 124 can be provided as the first auxiliary electrode tab 125.

[0207] For example, the first-1 uncoated negative electrode portion 122b of the first electrode assembly 100 can be provided as the third-1 uncoated portion 132, and the assembly of the third-1 uncoated portions 132 can be provided as the third electrode tab 130.

[0208] For example, the first-second uncoated negative electrode portion 124b of the first electrode assembly 100 can be provided as the third-second uncoated portion 134, and the assembly of the third-second uncoated portions 134 can be provided as the third auxiliary electrode tab 135.

[0209] For example, the second-first positive electrode uncoated portion 222a of the second electrode assembly 200 can be provided as the second-first uncoated portion 222, and the assembly of the second-first uncoated portions 222 can be provided as the second electrode tab 220.

[0210] For example, the second-second positive electrode uncoated portion 224a of the second electrode assembly 200 can be provided as the second-second uncoated portion 224, and the assembly of the second-second uncoated portions 224 can be provided as the second auxiliary electrode tab 225.

[0211] For example, the second-first uncoated negative electrode portion 222b of the second electrode assembly 200 can be provided as the fourth-first uncoated portion 232, and the assembly of the fourth-first uncoated portions 232 can be provided as the fourth electrode tab 230.

[0212] For example, the second-second negative electrode uncoated portion 224b of the second electrode assembly 200 can be provided as the fourth-second uncoated portion 234, and the assembly of the fourth-second uncoated portions 234 can be provided as the fourth auxiliary electrode tab 235.

[0213] In one embodiment, the first electrode tab 120 and the first auxiliary electrode tab 125 can be provided as positive electrode tabs of the first electrode assembly 100. The third electrode tab 130 and the third auxiliary electrode tab 135 can be provided as negative electrode tabs of the first electrode assembly 100.

[0214] In one embodiment, the second electrode tab 220 and the second auxiliary electrode tab 225 can serve as positive electrodes for the second electrode assembly 200. The fourth electrode tab 230 and the fourth auxiliary electrode tab 235 can serve as negative electrodes for the second electrode assembly 200.

[0215] Figure 7This is a schematic perspective view illustrating an electrode assembly and a current collector according to an exemplary embodiment. Figure 7 For ease of explanation, cover plate 400 and housing 500 are omitted.

[0216] Reference Figure 7 The stacked structure of the first electrode assembly 100 and the second electrode assembly 200 may be provided with current collector plates 300 on both sides.

[0217] In some embodiments, the current collector 300 may include: a first current collector 300a, disposed on one side of the stacked structure and electrically connected to the first electrode tab 120 and the second electrode tab 220; and a second current collector 300b, disposed on the other side of the stacked structure and electrically connected to the third electrode tab 130 and the fourth electrode tab 230.

[0218] For example, the first current collector 300a can be provided as a positive current collector. In this case, the first current collector 300a can be electrically connected to the positive terminal 420a.

[0219] For example, the second current collector 300b can be provided as a negative current collector. In this case, the second current collector 300b can be electrically connected to the negative terminal 420b.

[0220] Figure 8 It is along Figure 7 A schematic cross-sectional view of line A-A' viewed from a third-party perspective. Figure 9 It is along Figure 7 A schematic cross-sectional view of the B-B' line viewed from the third-party perspective.

[0221] like Figure 8 As shown, the first uncoated portion 122 protruding from one side of the first electrode assembly 100 can be bent in a first direction. The second uncoated portion 224 protruding from one side of the second electrode assembly 200 can contact or support the bent first uncoated portion 122.

[0222] like Figure 9 As shown, the second-first uncoated portion 222 protruding from one side of the second electrode assembly 200 can be bent in the opposite direction to the first direction. The first-second uncoated portion 124 protruding from one side of the first electrode assembly 100 can contact or support the bent second-first uncoated portion 222.

[0223] In some embodiments, the upper surfaces of the curved first-1 uncoated portion 122 and the second-1 uncoated portion 222 can be connected to the current collector 300. For example, the upper surface of the first-1 uncoated portion 122 and the current collector 300 can be in contact, and the upper surface of the second-1 uncoated portion 222 and the current collector 300 can be in contact.

[0224] According to one embodiment, by providing a current collector 300 on the first-1 uncoated portion 122 and the second-1 uncoated portion 222 and applying pressure, the connection stability and space utilization of the current collector 300 and the stacked structure can be improved.

[0225] In some embodiments, the current collector 300 may include a welding portion 310, wherein a first electrode tab 120 including a first uncoated portion 122 and a second electrode tab 220 including a second uncoated portion 222 are welded to the welding portion 310.

[0226] For example, the first electrode tab 120 and the second electrode tab 220 can respectively contact the first current collector plate 300a and be welded by laser welding. Therefore, the upper surfaces of the first electrode tab 120 and the second electrode tab 220 and the welded part of the first current collector plate 300a can be formed.

[0227] For example, the third electrode tab 130 and the fourth electrode tab 230 can respectively contact the second current collector plate 300b and be welded by laser welding. Therefore, a welded portion can be formed on the upper surfaces of the third electrode tab 130 and the fourth electrode tab 230 and on the second current collector plate 300b.

[0228] The laser welding can include welding techniques commonly used in the art. For example, the laser welding can include fillet welding, lap joint welding, etc.

[0229] In some embodiments, the welding portion 310 may be disposed on the surface of the current collector plate 300 adjacent to the first electrode assembly 100 and the second electrode assembly 200. Therefore, the entire electrode tabs 120, 130, 220, and 230 are covered by the current collector plate 300, thereby improving the manufacturing convenience, driving reliability, and mechanical stability of the secondary battery.

[0230] Figure 1 The form of the housing 500 shown is exemplary and can be varied depending on the shape and size of the first electrode assembly 100 and the second electrode assembly 200, as well as the structure of the module or battery pack using the secondary battery.

Claims

1. A secondary battery, comprising: The first electrode assembly includes a first electrode tab and a first auxiliary electrode tab protruding from the same surface as the first electrode tab, wherein the first electrode tab includes a plurality of first-1 uncoated portions that are respectively bent in a first direction; The second electrode assembly includes a second electrode tab and a second auxiliary electrode tab protruding from the same surface as the second electrode tab. The second electrode tab includes a plurality of second-1 uncoated portions stacked on the first electrode assembly along the first direction and bent in the opposite direction to the first direction. as well as The current collector plate completely covers and is electrically connected to the first electrode tab and the second electrode tab. The first electrode tab bends in the first direction to contact the second auxiliary electrode tab, and the second electrode tab bends in the opposite direction to the first direction to contact the first auxiliary electrode tab.

2. The secondary battery according to claim 1, wherein, The first electrode tab and the second electrode tab are not arranged on the same line in the first direction, and the first auxiliary electrode tab and the second auxiliary electrode tab are not arranged on the same line in the first direction.

3. The secondary battery according to claim 1, wherein, The first electrode tab and the second auxiliary electrode tab are arranged on the same line in the first direction.

4. The secondary battery according to claim 1, wherein, The first electrode tab is supported by one end of the second auxiliary electrode tab, and the second electrode tab is supported by one end of the first auxiliary electrode tab.

5. The secondary battery according to claim 1, wherein, The first auxiliary electrode tab includes a plurality of unbent first-second uncoated portions, and the second auxiliary electrode tab includes a plurality of unbent second-second uncoated portions.

6. The secondary battery according to claim 1, wherein, The first electrode tab and the second electrode tab are opposite each other in a first diagonal direction that is inclined relative to the first direction.

7. The secondary battery according to claim 1, wherein, The length of each of the plurality of uncoated portions 1-1 and the plurality of uncoated portions 2-1 in the first direction is less than 0.5 times the width of the current collector.

8. The secondary battery according to claim 1, wherein, The ratio of the length of the first electrode tab in the first direction to the length of the second electrode tab in the first direction is 0.5 to 1.

5.

9. The secondary battery according to claim 1, wherein, The number of the plurality of uncoated portions 1-1 included in the first electrode tab is 5 to 100, and the number of the plurality of uncoated portions 2-1 included in the second electrode tab is 5 to 100.

10. The secondary battery according to claim 1, wherein, The width directions of the first electrode assembly and the second electrode assembly are respectively the first direction; the length directions of the first electrode assembly and the second electrode assembly are respectively the second direction; and the height directions of the first electrode assembly and the second electrode assembly are respectively the third direction. The first electrode tab and the first auxiliary electrode tab are spaced apart in the third direction, and the second electrode tab and the second auxiliary electrode tab are spaced apart in the third direction.

11. The secondary battery according to claim 1, wherein, The width directions of the first electrode assembly and the second electrode assembly are respectively the first direction; the length directions of the first electrode assembly and the second electrode assembly are respectively the second direction; and the height directions of the first electrode assembly and the second electrode assembly are respectively the third direction. The shortest distance between the first electrode tab and the second electrode tab is less than or equal to the third-direction length of the first electrode tab, and the shortest distance is less than or equal to the third-direction length of the second electrode tab.

12. The secondary battery according to claim 1, wherein, The first electrode tab protrudes from one side of the first electrode assembly, and the second electrode tab protrudes from one side of the second electrode assembly. The first electrode assembly further includes a third electrode tab, the third electrode tab comprising a plurality of third-1 uncoated portions protruding from the other side of the first electrode assembly and respectively bending in the first direction. The second electrode assembly further includes a fourth electrode tab, which includes a plurality of fourth-1 uncoated portions protruding from the other side of the second electrode assembly and bending in the opposite direction to the first direction.

13. The secondary battery according to claim 12, wherein, The first electrode assembly further includes a third auxiliary electrode tab, which protrudes from the same surface as the third electrode tab and includes a plurality of third-second uncoated portions. The second electrode assembly further includes a fourth auxiliary electrode tab that protrudes from the same surface as the fourth electrode tab and includes a plurality of fourth-second uncoated portions.

14. The secondary battery according to claim 13, wherein, The first electrode tab and the third auxiliary electrode tab are arranged on the same line in a second direction perpendicular to the first direction. The third electrode tab and the first auxiliary electrode tab are arranged on the same line in the second direction. The second electrode tab and the fourth auxiliary electrode tab are arranged on the same line in the second direction. The fourth electrode tab and the second auxiliary electrode tab are arranged on the same line in the second direction.

15. The secondary battery according to claim 14, wherein, The first electrode tab and the second electrode tab are opposite each other in a first diagonal direction inclined relative to the first direction. The third electrode tab and the fourth electrode tab are opposite each other in a second diagonal direction that is inclined relative to the first direction in a direction opposite to the first diagonal direction.

16. The secondary battery according to claim 13, wherein, The first electrode tab and the third electrode tab are arranged on the same line in a second direction perpendicular to the first direction. The first auxiliary electrode tab and the third auxiliary electrode tab are arranged on the same line in the second direction. The second electrode tab and the fourth electrode tab are arranged on the same line in the second direction. The second auxiliary electrode tab and the fourth auxiliary electrode tab are arranged on the same line in the second direction.

17. The secondary battery according to claim 1, wherein, The current collector includes a welded portion formed by welding the first electrode tab and the second electrode tab to the current collector.

18. The secondary battery according to claim 17, wherein, The welding portion is disposed on the surface of the current collector plate adjacent to the first electrode assembly and the second electrode assembly.

19. The secondary battery according to claim 1, further comprising: A housing that accommodates the first electrode assembly and the second electrode assembly; Cover plate, sealing the housing; as well as The electrode terminal is combined with the cover plate and electrically connected to the electrode tab.

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