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 first uncoated portions each bent in a first direction; a second electrode assembly stacked in the first direction on the first electrode assembly, the second electrode assembly including a second electrode tab including a plurality of second uncoated portions each bent in a direction opposite to the first direction; the first electrode tab and the second electrode tab are arranged in the first direction, the collector plate completely covers the first electrode tab and the second electrode tab and is electrically connected with the first electrode tab and the second electrode tab, and the first electrode tab and the second electrode tab are not arranged on the same line in the first direction.

Description

Technical Field

[0001] The disclosed matter of the present application relates to a secondary battery. Background Art

[0002] Secondary 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 notebook computers (PCs). In addition, battery modules or battery packs including secondary batteries are recently developed and used as power sources for environmentally friendly cars.

[0003] The secondary battery may include an electrode assembly including a positive electrode, a negative electrode and a separator, and an electrolyte impregnated with the electrode assembly. The secondary battery may also include an outer package accommodating the electrode assembly and the electrolyte.

[0004] For example, the electrode assembly may be formed into a jelly form by winding or folding the separator, or may be formed into a stacked form by laminating the separators.

[0005] A collector plate for transmitting current may be arranged between an uncoated, non-coated portion of an electrode (e.g., an electrode tab) and a terminal. For example, the collector plate may be double-bent and joined to the non-coated portion, or a flat collector plate may be joined to the folded surface of the non-coated portion when the non-coated portion is folded. The volume occupied by the flat collector plate is relatively small, thereby increasing the energy density per unit volume of the secondary battery.

[0006] Recently, a method of welding a plurality of uncoated portions to a current collector plate at one time has been developed. However, at least a portion of the plurality of uncoated portions protrudes outside the current collector plate, which may reduce processability. Summary of the invention

[0007] According to an aspect of the present disclosure, a secondary battery having improved driving reliability and processability may be provided.

[0008] 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, the first electrode tab including a plurality of first uncoated portions each bent in a first direction; a second electrode assembly, the second electrode assembly being stacked on the first electrode assembly in the first direction, the second electrode assembly including a second electrode tab, the second electrode tab including a plurality of second uncoated portions each bent in a direction opposite to the first direction; and a collector plate, the collector plate fully covering the first electrode tab and the second electrode tab and being electrically connected to the first electrode tab and the second electrode tab, wherein the first electrode tab and the second electrode tab are not arranged on the same line in the first direction.

[0009] In some embodiments, the first electrode tab and the second electrode tab may be opposed to each other in a first diagonal direction inclined relative to the first direction.

[0010] In some embodiments, the length of each of the plurality of first non-coating portions and the plurality of second non-coating portions in the first direction may be less than or equal to 0.5 times the width of the collector plate.

[0011] In some embodiments, the ratio of the length of the second electrode tab in the first direction to the length of the first electrode tab in the first direction may be 0.5 to 1.5.

[0012] In some embodiments, the number of the plurality of first uncoated portions included in the first electrode tab is 5 to 100, and the number of the plurality of second uncoated portions included in the second electrode tab is 5 to 100.

[0013] In some embodiments, the width direction of the first electrode assembly and the width direction of the second electrode assembly are each the first direction, the length direction of the first electrode assembly and the length direction of the second electrode assembly are each the second direction, the height direction of the first electrode assembly and the height direction of the second electrode assembly are each the third direction, the length of the first electrode ear in the third direction is less than 0.5 times the length of the first electrode assembly in the third direction, and the length of the second electrode ear in the third direction is less than 0.5 times the length of the second electrode assembly in the third direction.

[0014] In some embodiments, the shortest distance between the first electrode tab and the second electrode tab may be less than the length of the first electrode tab in the third direction, and the shortest distance may be less than the length of the second electrode tab in the third direction.

[0015] In some embodiments, the first electrode assembly may include: the first electrode tab, the first electrode tab protruding from one side of the first electrode assembly; and a third electrode tab, the third electrode tab including a plurality of third uncoated portions protruding from the other side of the first electrode assembly and each bent in the first direction, and the second electrode assembly may include: the second electrode tab, the second electrode tab protruding from one side of the second electrode assembly; and a fourth electrode tab, the fourth electrode tab including a plurality of fourth uncoated portions protruding from the other side of the second electrode assembly and each bent in a direction opposite to the first direction.

[0016] In some embodiments, the first electrode tab and the third electrode tab may not be arranged on the same line in a second direction perpendicular to the first direction, and the second electrode tab and the fourth electrode tab may not be arranged on the same line in the second direction.

[0017] In some embodiments, the second electrode tab and the fourth electrode tab may be opposite to each other in a second diagonal direction that is inclined relative to the first direction and in a direction opposite to the first diagonal direction.

[0018] 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, and the second electrode tab and the fourth electrode tab may be arranged on the same line in the second direction.

[0019] In some embodiments, the second electrode tab and the fourth electrode tab may be opposite to each other in the first diagonal direction.

[0020] In some embodiments, the first electrode tab and the second electrode tab are provided as positive electrode tabs, and the third electrode tab and the fourth electrode tab are provided as negative electrode tabs.

[0021] In some embodiments, the length of each of the plurality of third non-coating portions and the plurality of fourth non-coating portions in the first direction may be less than or equal to 0.5 times the width of the collector plate.

[0022] In some embodiments, the collector plate may include a welding portion to which the first electrode tab and the second electrode tab are welded.

[0023] In some embodiments, the welding portion may be disposed on a surface of the collector plate adjacent to the first electrode assembly and the second electrode assembly.

[0024] In some embodiments, it may further include: a shell, which accommodates the first electrode assembly and the second electrode assembly; a cover plate, which seals the shell; and an electrode terminal, which is combined with the cover plate and electrically connected to the electrode tab.

[0025] According to an embodiment of the present disclosure, no further bending process is required for the protruding non-coating portion, and the thickness of the secondary battery is reduced, thereby improving manufacturability and structural stability.

[0026] According to an embodiment of the present disclosure, it is possible to prevent heating and damage of a secondary battery while improving processability and reliability.

[0027] The secondary battery disclosed in the present invention can be widely used in electric vehicles, battery charging stations, and other green technology fields such as solar power generation and wind power generation using batteries. In addition, the secondary battery disclosed in the present invention can be used in eco-friendly electric vehicles and hybrid vehicles, etc., which are used to suppress air pollution and greenhouse gas emissions to prevent climate change. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment.

[0029] Figure 2 is a reference diagram for explaining the first diagonal direction.

[0030] Figure 3 is a schematic exploded perspective view of an electrode assembly according to an exemplary embodiment.

[0031] Figure 4 is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment.

[0032] Figure 5 It is a reference diagram for explaining the second diagonal direction.

[0033] Figure 6 is a schematic perspective view for explaining a first electrode assembly and a second electrode assembly according to an exemplary embodiment.

[0034] Figure 7 is a schematic perspective view illustrating an electrode assembly and a current collector plate according to an exemplary embodiment.

[0035] Figure 8 It is along Figure 7 Schematic cross-sectional view observed along the A-A' line.

[0036] Fig. 9 It is along Figure 7Schematic cross-sectional view of the BB' line. DETAILED DESCRIPTION

[0037] An embodiment of the present disclosure provides a secondary battery.

[0038] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings, but these are merely examples, and the present disclosure is not limited to the specific embodiments described by way of example.

[0039] The terms "top", "side", "one side", "the other side", "one side", "the other side" etc. used in this specification are used in a relative sense to distinguish the positions of features and do not specify absolute positions.

[0040] The term "first direction" used in this specification may refer to a direction in which the first electrode tab 120 is bent. The first direction may refer to a direction in which the first electrode assembly 100 and the second electrode assembly 200 are stacked. The first direction may refer to a width direction of the first electrode assembly 100 and / or the second electrode assembly 200. The first direction may refer to Figure 1 and Figures 3 to 7 The first direction in .

[0041] The term "second direction" used in this specification may refer to a length direction of the first electrode assembly 100 and / or the second electrode assembly 200. The second direction may refer to a direction from the one side of the first electrode assembly 100 and / or the second electrode assembly 200 toward the other side. Figure 1 and Figures 3 to 7 The second direction in .

[0042] The term "third direction" used in this specification may refer to a height direction of the first electrode assembly 100 and / or the second electrode assembly 200. The third direction may refer to Figure 1 and Figures 3 to 7 The third direction may represent a direction perpendicular to the first direction and the second direction.

[0043] Figure 1 is an exploded perspective view of a secondary battery according to an exemplary embodiment.

[0044] refer to Figure 1 , a secondary battery may include a first electrode assembly 100 and a second electrode assembly 200 .

[0045] The first electrode assembly 100 and the second electrode assembly 200 may be arranged in a first direction. For example, the second electrode assembly 200 may be stacked in the first direction on the first electrode assembly 100. In one embodiment, the second electrode assembly 200 may be directly arranged on the first electrode assembly 100.

[0046] For example, the first electrode assembly 100 and the second electrode assembly 200 may be combined, coupled, or assembled to be provided as one battery constituent unit.

[0047] In an exemplary embodiment, the first electrode assembly 100 may include a first electrode tab 120 including a plurality of first uncoated portions each bent in the first direction. The second electrode assembly 200 may include a second electrode tab 220 including a plurality of second uncoated portions each bent in a direction opposite to the first direction.

[0048] For example, each of the first electrode assembly 100 and the second electrode assembly 200 may include a plurality of electrodes that are repeatedly stacked and a separator interposed between the electrodes.

[0049] Each of the plurality of electrodes may include a non-coating portion. For example, each of the electrodes included in the first electrode assembly 100 may include a first non-coating portion 122 , and each of the electrodes included in the second electrode assembly 200 may include a second non-coating portion 222 .

[0050] For example, the first electrode tab 120 may include a set of a plurality of first non-coating portions 122 , and the second electrode tab 220 may include a set of a plurality of second non-coating portions 222 .

[0051] In one embodiment, the plurality of first uncoated portions 122 may not be otherwise joined or pressed against each other. In one embodiment, the plurality of second uncoated portions 222 may not be otherwise joined or pressed against each other.

[0052] In some embodiments, the number of the plurality of first uncoated portions 122 included in the first electrode tab 120 may be 5 to 100 or 10 to 50. The number of the plurality of second uncoated portions 222 included in the second electrode tab 220 may be 5 to 100 or 10 to 50. Within the above range, the output characteristics of the secondary battery can be improved while improving the space efficiency.

[0053] In an exemplary embodiment, the first electrode tab 120 may be bent in a first direction, and the second electrode tab 220 may be bent in a direction opposite to the first direction. For example, a plurality of first uncoated portions 122 may be bent in a first direction, and a plurality of second uncoated portions 222 may be bent in a direction opposite to the first direction. The first electrode assembly 100 and the second electrode assembly 200 are stacked, so that the bent first electrode tab 120 and the second electrode tab 220 may not protrude outside the electrode assembly. As a result, no further bending process is required for the protruding portion, and the thickness of the secondary battery is reduced, which can improve processability and structural stability.

[0054] The term “a direction opposite to the first direction” used in this specification may refer to a direction in which the second uncoated portion and / or the second electrode tab 220 is bent.

[0055] In an exemplary embodiment, the first electrode tab 120 and the second electrode tab 220 may not be arranged on the same line in the first direction, thereby preventing the secondary battery from heating and being damaged due to contact between the first electrode tab 120 and the second electrode tab 220 and improving processability and reliability.

[0056] In some embodiments, the first electrode tab 120 and the second electrode tab 220 may be opposite to each other in a first diagonal direction inclined relative to the first direction.

[0057] For example, the first diagonal direction may be a direction from the center of the first uncoated portion 122 that is farthest from the second electrode assembly 200 toward the center of the second uncoated portion 222 that is farthest from the first electrode assembly 100. The center of the first uncoated portion may refer to the center point when the first uncoated portion is not bent, and the center of the second uncoated portion may refer to the center point when the second uncoated portion is not bent.

[0058] Figure 2 is a reference diagram for explaining the first diagonal direction.

[0059] refer to Figure 2 , the first diagonal direction may represent a direction extending between the first direction and the third direction on a plane formed by the first direction and the third direction.

[0060] For example, the first diagonal direction may be inclined by 1° to 89°, 10° to 80°, or 30° to 60° relative to the first direction.

[0061] Reference again Figure 1The secondary battery may include a collector plate 300 , which fully 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 .

[0062] According to an embodiment, the collector plate 300 may include a plate shape, thereby reducing the volume of the collector plate 300, improving the capacity and energy density of the secondary battery, increasing the contact area between the collector plate 300 and the electrode tabs 120 and 220, and reducing the impedance of the secondary battery.

[0063] In one embodiment, a conductive metal plate may be provided as the current collecting plate 300 .

[0064] Reference later Figure 8 and Fig. 9 The connection structure between the current collector plate 300 and the electrode tabs 120 and 220 will be described.

[0065] In some embodiments, the length L of each of the plurality of first uncoated portions in the first direction may be less than 0.5 times the width W of the collector plate 300, and the length L of each of the plurality of second uncoated portions in the first direction may be less than 0.5 times the width W of the collector plate 300. Within the above range, the electrode tabs 120 and 220 do not protrude outside the electrode assemblies 100 and 200, thereby omitting further bending processes and reducing the volume of the secondary battery.

[0066] According to one embodiment, the length L of each of the plurality of first uncoated portions and the plurality of second uncoated portions in the first direction may be 0.01 to 0.5 times the width W of the collector plate 300. Thus, the collector plate 300 and the electrode tabs 120 and 220 can be stably connected.

[0067] In some embodiments, the length of the first electrode tab 120 in the third direction may be less than 0.5 times or 0.1 to 0.4 times the length of the first electrode assembly 100 in the third direction. Within this range, the output characteristics of the secondary battery can be improved while improving space efficiency.

[0068] In some embodiments, the length of the second electrode tab 220 in the third direction may be less than 0.5 times or 0.1 to 0.4 times the length of the second electrode assembly 200 in the third direction. Within this range, the output characteristics of the secondary battery can be improved while improving space efficiency.

[0069] In some embodiments, the shortest distance D between the first electrode tab 120 and the second electrode tab 220 may be less than the length of the first electrode tab 120 in the third direction. Within the above range, the heating and damage caused by the contact between the electrode tabs 120 and 220 can be suppressed, thereby improving the space efficiency of the secondary battery.

[0070] In some embodiments, the shortest distance D between the first electrode tab 120 and the second electrode tab 220 may be less than the length of the second electrode tab 220 in the third direction. Within the above range, the heating and damage caused by the contact between the electrode tabs 120 and 220 can be suppressed, thereby improving the space efficiency of the secondary battery.

[0071] In some embodiments, the ratio of the length of the second electrode tab 220 in the first direction to the length of the first electrode tab 120 in the first direction may be 0.5 to 1.5 or 0.8 to 1.2. Within the above range, the secondary battery can be prevented from overcurrent in a specific part, and the life characteristics and driving stability can be improved.

[0072] In some embodiments, the length of the first electrode tab 120 along the first direction may be substantially the same as the length of the second electrode tab 220 along the first direction.

[0073] Figure 3 is a schematic exploded perspective view of an electrode assembly according to an exemplary embodiment. For example, Figure 3 The electrode stacking structure included in the first electrode assembly 100 and / or the second electrode assembly 200 may be shown. For example, the first electrode assembly 100 and the second electrode assembly 200 may each include a jelly roll form in which a plurality of electrode stacking structures are repeatedly stacked. For example, the electrode assembly 150 may be formed by winding, stacking, z-folding, stack-folding, etc., the separators 105 and 205.

[0074] refer to 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 separator 105 between the first positive electrode 102 and the first negative electrode 104 .

[0075] According to an exemplary embodiment, the first positive electrode 102 and the first negative electrode 104 are alternately and repeatedly stacked with the first separator 105 interposed therebetween, thereby being able to define the first electrode assembly 100 .

[0076] The first positive electrode 102 and the first negative electrode 104 may each include a first coating portion 112 and a first non-coating portion 122 .

[0077] The first coating 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 non-coating portion 122 may indicate a region where the first active material layer 115 is not disposed on the first current collector 110. The first non-coating portion 122 may extend from the first current collector 110 of the first coating portion 112, thereby protruding from the first coating portion 112.

[0078] In one embodiment, the first active material layer 115 may be disposed on both surfaces of the first current collector 110 .

[0079] In some embodiments, the first positive electrode coating portion 112a and the first negative electrode coating portion 112b may overlap each other in the electrode stacking direction. For example, the first separator 105 may be interposed between the first positive electrode coating portion 112a and the first negative electrode coating portion 112b.

[0080] According to an exemplary embodiment, the first positive electrode uncoated portion 122a and the first negative electrode uncoated portion 122b may protrude in opposite directions to each other. For example, the first positive electrode uncoated portion 122a may protrude in one direction from the first positive electrode coated portion 112a, and the first negative electrode uncoated portion 122b may protrude in a direction opposite to the one direction from the first negative electrode coated portion 112b.

[0081] 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 separator 205 between the second positive electrode 202 and the second negative electrode 204 .

[0082] According to an exemplary embodiment, the second positive electrode 202 and the second negative electrode 204 are alternately and repeatedly stacked with the second separator 205 in between, thereby defining the second electrode assembly 200 .

[0083] The second positive electrode 202 and the second negative electrode 204 may each include a second coating portion 212 and a second non-coating portion 222 .

[0084] 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 non-coating portion 222 may indicate a region where the second active material layer 215 is not disposed on the second current collector 210. The second non-coating portion 222 may extend from the second current collector 210 of the second coating portion 212, thereby protruding from the second coating portion 212.

[0085] In one embodiment, the second active material layer 215 may be disposed on both surfaces of the second current collector 210 .

[0086] In some embodiments, the second positive electrode coating portion 212a and the second negative electrode coating portion 212b may overlap each other in the electrode stacking direction. For example, the second separator 105 may be interposed between the second positive electrode coating portion 212a and the second negative electrode coating portion 212b.

[0087] According to an exemplary embodiment, the second positive electrode non-coating portion 222a and the second negative electrode non-coating portion 222b may protrude in opposite directions to each other. For example, the second positive electrode non-coating portion 222a may protrude from the second positive electrode coating portion 212a in one direction, and the second negative electrode non-coating portion 222b may protrude from the second negative electrode coating portion 212b in a direction opposite to the one direction.

[0088] In an exemplary embodiment, the positive electrode 102 , 202 may include a positive electrode current collector and a positive electrode active material layer disposed on at least one side of the positive electrode current collector.

[0089] For example, the positive electrode current collector may include stainless steel, nickel, aluminum, titanium, or alloys thereof. The positive electrode current collector may also include aluminum or stainless steel surface-treated with carbon, nickel, titanium, or silver. For example, the thickness of the positive electrode current collector may be 10 μm to 50 μm.

[0090] The positive electrode active material layer may include a positive electrode active material. For example, the positive electrode active material may include a compound capable of reversibly inserting and extracting lithium ions.

[0091] According to an exemplary embodiment, the positive active material may include lithium-nickel metal oxide. The lithium-nickel metal oxide may further include at least one of cobalt (Co), manganese (Mn), and aluminum (Al).

[0092] In some embodiments, the positive electrode active material or the lithium-nickel metal oxide may include a layered structure or a crystal structure represented by the following Chemical Formula 1.

[0093]

Chemical formula 1

[0094] The chemical structure represented by Chemical Formula 1 represents the bonding relationship included in the layered structure or crystal structure of the positive electrode active material, and does not exclude other additional elements. For example, M may include Co and / or Mn, and Co and / or Mn are provided together with Ni as the main active element of the positive electrode active material. Chemical Formula 1 is provided to express the bonding relationship of the main active elements, and should be understood to include the introduction and substitution of additional elements.

[0095] In one embodiment, an auxiliary element may be further included, and the auxiliary element is added to the main active element to enhance the chemical stability of the positive electrode active material or the layered structure / crystal structure. It should be understood that the auxiliary element may be mixed into the layered structure / crystal structure to form a bond, which is also included in the chemical structure represented by Chemical Formula 1.

[0096] The auxiliary element may include, for example, at least one of the group consisting of Na, Mg, Ca, Y, Ti, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Cu, Ag, Zn, B, Al, Ga, C, Si, Sn, Sr, Ba, Ra, P and Zr. The auxiliary element may also function as an auxiliary active element such as Al that contributes to the capacity / output activity of the positive electrode active material together with Co or Mn.

[0097] For example, the positive active material or the lithium-nickel metal oxide may include a layered structure or a crystal structure represented by the following Chemical Formula 1-1.

[0098]

Chemical formula 1-1

[0099] The positive electrode active material may further include a coating element or a doping element. For example, as the coating element or the doping element, an element substantially the same as or similar to the auxiliary element described above may be used. For example, among the above elements, two or more may be used as the coating element or the doping element alone or in combination.

[0100] The coating element or the doping element may also exist on the surface of the lithium-nickel metal oxide particle or penetrate through the surface of the lithium-nickel metal composite oxide particle to be included in the bonding structure represented by the Chemical Formula 1 or Chemical Formula 1-1.

[0101] The positive electrode active material may include a nickel-cobalt-manganese (NCM)-based lithium oxide. In this case, the NCM-based lithium oxide having an increased nickel content may be used.

[0102] Ni can be provided as a transition metal related to the output and capacity of the lithium secondary battery. Therefore, as described above, by using a high-content (High-Ni) component in the positive electrode active material, a high-capacity positive electrode and a high-capacity lithium secondary battery can be provided.

[0103] However, as the Ni content increases, the long-term storage stability and life stability of the positive electrode or secondary battery may be relatively reduced, and the side reaction with the electrolyte may also increase. However, according to an exemplary embodiment, Co may be included to maintain conductivity while Mn may be used to improve life stability and capacity retention characteristics.

[0104] The Ni content in the NCM-based lithium oxide (e.g., the molar percentage of nickel in the total molar number of nickel, cobalt and manganese) may be greater than 0.5, greater than 0.6, greater than 0.7 or greater than 0.8. In some embodiments, the Ni content may 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.

[0105] In some embodiments, the positive electrode active material may further include a lithium cobalt oxide active material, a lithium manganese oxide active material, a lithium nickel oxide active material or a lithium iron phosphate (LFP) active material (eg, LiFePO 4 ).

[0106] In some embodiments, the positive electrode active material may include, for example, LLO (Li rich layered oxide) / OLO (Over Lithiated Oxide) type active materials, Mn-rich type active materials, Co-less type active materials, etc. having a chemical structure or crystal structure represented by Chemical Formula 2. They may be used alone or in combination of two or more.

[0107]

Chemical formula 2

[0108] In an exemplary embodiment, the negative electrodes 104 and 204 may include a negative electrode current collector and a negative electrode active material layer disposed on at least one surface of the negative electrode current collector.

[0109] 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, a polymer substrate coated with a conductive metal, etc. They may 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.

[0110] The negative electrode active material layer may include a negative electrode active material.

[0111] For example, the negative electrode active material may include a material capable of intercalating and deintercalating lithium ions. For example, carbon-based materials such as crystalline carbon, amorphous carbon, carbon composites, and carbon fibers may be used as the negative electrode active material; lithium metal; lithium alloys; silicon (Si)-containing substances or tin (Sn)-containing substances, etc. They may be used alone or in combination of two or more.

[0112] The amorphous carbon may include hard carbon, soft carbon, coke, mesocarbon microbead (MCMB), mesophase pitch-based carbon fiber (MPCF), etc.

[0113] The crystalline carbon may include graphite-based carbons such as natural graphite, artificial graphite, graphitized coke, graphitized MCMB, graphitized MPCF, etc.

[0114] The lithium metal may include pure lithium metal and / or lithium metal formed with a protective layer for inhibiting dendrite growth, etc. In one embodiment, as the negative electrode active material layer, a lithium metal-containing layer deposited or coated on the negative electrode current collector may be used. In one embodiment, a lithium thin film layer may also be used as the negative electrode active material layer.

[0115] As the elements included in the lithium alloy, aluminum, zinc, bismuth, cadmium, antimony, silicon, lead, tin, gallium, indium, etc. may be mentioned. They may be used alone or in combination of two or more.

[0116] The silicon-containing substance may provide further improved capacity characteristics. The silicon-containing substance may include Si, SiO x (0 < x < 2), SiO doped with a metal x (0 < x < 2), silicon-carbon composites, etc.

[0117] The metal may include lithium and / or magnesium, and SiO doped with metal x (0 < x < 2) may include metal silicate.

[0118] In some embodiments, the electrode composition may further include a conductive material.

[0119] For example, the conductive material may be added to enhance the conductivity of the electrode and / or the mobility of lithium ions or electrons. For example, the conductive material may include carbon-based conductive materials such as conductive carbon, graphite, carbon black, acetylene black, Ketjen black, graphene, carbon nanotubes (CNT), VGCF (vapor-grown carbon fiber), carbon fiber, etc. and / or metal-based conductive materials including perovskite substances such as tin, tin oxide, titanium oxide, LaSrCoO3, LaSrMnO3, etc. They may be used alone or in combination of two or more.

[0120] In some embodiments, the separators 105, 205 may be configured to prevent electrical short circuits between the positive electrodes 102, 202 and the negative electrodes 104, 204 and to allow the flow of ions. For example, the thickness of the separator may be 10 μm to 20 μm.

[0121] For example, the separators 105, 205 may include a porous polymer membrane or a porous non-woven fabric.

[0122] The porous polymer membrane may include polyolefin polymers such as ethylene polymer, propylene polymer, ethylene / butene copolymer, ethylene / hexene copolymer, and ethylene / methacrylate copolymer. They may be used alone or in combination of two or more.

[0123] The porous non-woven fabric may include glass fibers with high melting points, polyethylene terephthalate fibers, etc.

[0124] The separators 105, 205 may further include ceramic materials. For example, inorganic particles may be coated on or dispersed in the polymer membrane to improve heat resistance.

[0125] The separators 105, 205 may have a single-layer or multi-layer structure including the above-mentioned polymer membrane and / or non-woven fabric.

[0126] The secondary battery may include a case 500 accommodating the first electrode assembly 100 and the second electrode assembly. The case 500 may be provided as at least a portion of the outer surface of the secondary battery. In one embodiment, the case 500 may include metal. Thus, the impact on the first electrode assembly 100 and the second electrode assembly 200 may be mitigated.

[0127] The case 500 may include a receiving portion 510 for receiving the first electrode assembly 100 and the second electrode assembly 200 therein. For example, an opening may be formed on the upper surface of the case 500 to open the case 500 in the third direction. The first electrode assembly 100 and the second electrode assembly 200 may be received in the receiving portion 510 through the opening.

[0128] In some embodiments, the secondary battery may include a cap plate 400 sealing the housing 500. The cap plate 400 may be assembled on the housing 500. For example, the cap plate 400 and the opening of the housing 500 may be assembled to seal the receiving portion 510.

[0129] For example, the cover plate 400 may include a cover member 410. The cover member 410 may have a plate shape. The cover plate 400 may be combined, coupled or connected to the housing 500 through the cover member 410.

[0130] For example, the cap plate 400 may include an injection hole 440. The injection hole 440 may be a hole or an opening formed on the cover 410. The electrolyte may be injected into the interior of the case 500 through the injection hole 440.

[0131] For example, the cap plate 400 may include a vent hole 430. The vent hole 430 may be formed to penetrate the cover member 410. Through the vent hole 430, the space inside the housing 500 may be limitedly connected to the outside.

[0132] For example, an exhaust plate may be combined with the exhaust hole 430. When the internal pressure of the housing 500 reaches a set pressure or more, the exhaust plate may be broken. Thus, the gas inside the housing 500 may be discharged to the outside of the housing 500, and the internal pressure of the housing 500 may be reduced.

[0133] For example, the secondary battery may include an electrode terminal 420, which is combined with the cap plate 400 and electrically connected to the electrode tabs 120 and 220. The electrode terminal 420 may be combined with the cover 410. For example, the cover 410 may include an opening capable of being combined with the electrode terminal 420. The opening may penetrate the cover 410. The electrode terminal 420 may be electrically connected to the first electrode assembly 100 and the second electrode assembly 200 through the opening.

[0134] The 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 electrode tab, and the negative terminal 420b may be electrically connected to the negative electrode tab.

[0135] The electrode assemblies 100 and 200 may be housed in the housing 500 together with the electrolyte, thereby defining a lithium secondary battery. According to an exemplary embodiment, as the electrolyte, a non-aqueous electrolyte may be used. For example, the non-aqueous electrolyte may be injected into the housing 500 through the injection hole 440 of the cap plate 400.

[0136] The non-aqueous electrolyte may include a lithium salt as an electrolyte and an organic solvent. + X - represents the lithium salt, the negative ion of the lithium salt (X - ) can include 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 - 、(CF3CF2SO2)2N - wait.

[0137] The organic solvent may include, for example, propylene carbonate (PC), ethylene carbonate (EC), butylene carbonate, diethyl carbonate (DEC), dimethyl carbonate (DMC), ethyl methyl carbonate (EMC), methyl propyl carbonate, ethyl propyl carbonate, dipropyl carbonate, vinylene carbonate, methyl acetate (MA), ethyl acetate (EA), n-propyl acetate (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), diethylene glycol dimethyl ether (DME), ether, DEGDME), dimethoxyethane, tetrahydrofuran (THF), 2-methyltetrahydrofuran, ethyl alcohol, isopropyl alcohol, dimethyl sulfoxide, acetonitrile, dimethoxyethane, diethoxyethane, sulfolane, γ-butyrolactone, propylene sulfite, etc. These can be used alone or in combination of two or more.

[0138] The non-aqueous electrolyte may further include additives. The additives may include, for example, cyclic carbonate compounds, fluorinated carbonate compounds, sultone compounds, cyclic sulfate compounds, cyclic sulfite compounds, phosphate compounds, borate compounds, etc. These additives may be used alone or in combination of two or more.

[0139] The cyclic carbonate compound may include vinylene carbonate (VC), vinyl ethylene carbonate (VEC), and the like.

[0140] The fluorinated cyclic carbonate compound may include fluoroethylene carbonate (FEC) and the like.

[0141] The sultone compounds may include 1,3-propane sultone, 1,3-propene sultone, 1,4-butane sultone, and the like.

[0142] The cyclic sulfate ester compounds may include 1,2-ethylene sulfate, 1,2-propylene sulfate, and the like.

[0143] The cyclic sulfite compounds may include ethylene sulfite, buthylene sulfite, and the like.

[0144] The phosphate compound may include lithium difluoro bis-oxalato phosphate, lithium difluoro phosphate, and the like.

[0145] The borate compound may include lithium bis(oxalate) borate and the like.

[0146] In some embodiments, a solid electrolyte may be used instead of the non-aqueous electrolyte. In this case, the lithium secondary battery may be made into an all-solid-state battery. In addition, a solid electrolyte layer may be arranged between the positive electrode 102, 202 and the negative electrode 104, 204 to replace the above-mentioned separator 105, 205.

[0147] The solid electrolyte may include a sulfide electrolyte. As a non-limiting example, the sulfide 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, Li2S-P2S5-Zm S n (m, n are positive numbers, Z is Ge, Zn or Ga), Li2S-GeS2, Li2S-SiS2-Li3PO4, Li2S-SiS2-Li p MO q 、(p, 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), Li7-xPS6-xI x (0≤x≤2), etc. These can be used alone or in combination of two or more.

[0148] In one embodiment, the solid electrolyte may also include an oxide-based amorphous solid electrolyte such as Li2O-B2O3-P2O5, Li2O-SiO2, Li2O-B2O3, Li2O-B2O3-ZnO, etc.

[0149] Figure 4 is a schematic exploded perspective view of a secondary battery according to an exemplary embodiment. Figure 4 In the figure, for convenience of explanation, the electrode tabs 120, 130, 220, 230 are illustrated in an unbent state, but as mentioned above, it should be interpreted that the electrode tabs 120, 130, 220, 230 are arranged on the secondary battery in a bent state.

[0150] refer to Figure 4 The first electrode assembly 100 may include a first electrode tab 120 protruding from one side of the first electrode assembly 100 and a third electrode tab 130 protruding from the other side of the first electrode assembly 100 .

[0151] The third electrode tab 130 may include a plurality of third uncoated portions 132 protruding from the other side of the first electrode assembly 100 and each bent in the first direction.

[0152] The second electrode assembly 200 may include a second electrode tab 220 protruding from one side of the second electrode assembly 200 and a fourth electrode tab 230 protruding from the other side of the second electrode assembly 200 .

[0153] The fourth electrode tab 230 may include a plurality of fourth uncoated portions 232 protruding from the other side of the second electrode assembly 200 and each bent in a direction opposite to the first direction.

[0154] The first electrode assembly 100 and the second electrode assembly 200 may be stacked such that the one side of the first electrode assembly 100 and the one side of the second electrode assembly 200 meet, and the other side of the first electrode assembly 100 and the other side of the second electrode assembly 200 meet.

[0155] 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.

[0156] In some embodiments, the second electrode tab 220 and the fourth electrode tab 230 may be opposite to each other in a second diagonal direction that is tilted in a direction opposite to the first diagonal direction relative to the first direction. Thus, heating and damage of the secondary battery caused by contact between the second electrode tab 220 and the fourth electrode tab 230 can be prevented, thereby improving processability and reliability.

[0157] For example, the second diagonal direction may be a direction from the center of the third uncoated portion 132 that is farthest from the second electrode assembly 200 toward the center of the fourth uncoated portion 232 that is farthest from the first electrode assembly 100. The center of the third uncoated portion may indicate the center point of the third uncoated portion when it is not bent, and the center of the fourth uncoated portion may indicate the center point of the fourth uncoated portion when it is not bent.

[0158] Figure 5 It is a reference diagram for explaining the second diagonal direction.

[0159] refer to Figure 5 , the second diagonal direction can be represented by a direction symmetrical to the first diagonal direction with the third direction as a reference on a plane formed by the first direction and the third direction.

[0160] Figure 6 2 is a schematic perspective view for explaining a first electrode assembly and a second electrode assembly according to an exemplary embodiment. Figure 4 In the figure, for convenience of explanation, the electrode tabs 120, 130, 220, 230 are illustrated in an unbent state, but as mentioned above, it should be interpreted that the electrode tabs 120, 130, 220, 230 are arranged on the secondary electrode in a bent state.

[0161] refer to Figure 6The first electrode tab 120 and the third electrode tab 130 of the first electrode assembly 100 may 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 may be arranged on the same line in the second direction.

[0162] In some embodiments, the second electrode tab 220 and the fourth electrode tab 230 may face each other in the first diagonal direction, thereby preventing heating and damage of the secondary battery caused by contact between the second electrode tab 220 and the fourth electrode tab 230 , thereby improving processability and reliability.

[0163] In some embodiments, the length of each of the plurality of third uncoated portions and the plurality of fourth uncoated portions in the first direction may be less than 0.5 times the width of the collector plate, and in one embodiment, may be 0.01 times to 0.5 times. Thus, the collector plate 300 and the electrode tabs 130 and 230 can be stably connected.

[0164] In some embodiments, the first electrode tab 120 and the second electrode tab 220 may be provided as positive electrode tabs, and the third electrode tab 130 and the fourth electrode tab 230 may be provided as negative electrode tabs.

[0165] For example, the non-coating portion 122 a of the positive electrode of the first electrode assembly 100 may be provided as the first non-coating portion, and an aggregate of the first non-coating portions may be provided as the first electrode tab 120 .

[0166] For example, the uncoated portion 122 b of the negative electrode of the first electrode assembly 100 may be provided as the third uncoated portion, and an aggregate of the third uncoated portions may be provided as the third electrode tab 130 .

[0167] For example, the non-coating portion 222 a of the positive electrode of the second electrode assembly 200 may be provided as the second non-coating portion, and an aggregate of the second non-coating portions may be provided as the second electrode tab 220 .

[0168] For example, the non-coating portion 222 b of the negative electrode of the second electrode assembly 200 may be provided by the fourth non-coating portion, and an aggregate of the fourth non-coating portions is provided as the fourth electrode tab 230 .

[0169] In one embodiment, the first electrode tab 120 and the third electrode tab 130 may each provide a positive tab and a negative tab of the first electrode assembly 100. In one embodiment, the second electrode tab 220 and the fourth electrode tab 230 may each provide a positive tab and a negative tab of the second electrode assembly 200.

[0170] Figure 7 is a schematic perspective view showing an electrode assembly and a current collector plate according to an exemplary embodiment. Figure 5 In the figure, for the convenience of explanation, the cover plate 400 and the housing 500 are omitted.

[0171] refer to Figure 7 The collector plates 300 may be disposed on both side surfaces of the stacked structure of the first electrode assembly 100 and the second electrode assembly 200 .

[0172] In some embodiments, the collector plate 300 may include: a first collector plate 300a, which is arranged on one side of the stacked structure and electrically connects the first electrode tab 120 and the second electrode tab 220; and a second collector plate 300b, which is arranged on the other side of the stacked structure and electrically connects the third electrode tab 130 and the fourth electrode tab 230.

[0173] For example, the first collector plate 300a may be provided as a positive electrode collector plate. In this case, the first collector plate 300a may be electrically connected to the positive electrode terminal 420a.

[0174] For example, the second collector plate 300b may be provided as a negative electrode collector plate. In this case, the second collector plate 300b may be electrically connected to the negative electrode terminal 420b.

[0175] Figure 8 It is along Figure 7 A schematic cross-sectional view of line A-A' viewed in the third direction. Fig. 9 It is along Figure 7 A schematic cross-sectional view of the BB' line viewed in the third direction.

[0176] refer to Figure 8 and Fig. 9 The first non-coating portion 122 may protrude from the one side of the first electrode assembly 100 to be bent in the first direction. The second non-coating portion 222 may protrude from the one side of the second electrode assembly 200 to be bent in the direction opposite to the first direction.

[0177] In some embodiments, the collector plate 300 may be connected to the upper surface of the bent first non-coating portion 122 and the upper surface of the second non-coating portion 222. For example, the upper surface of the first non-coating portion 122 may be in contact with the collector plate 300, and the upper surface of the second non-coating portion 222 may be in contact with the collector plate 300.

[0178] According to one embodiment, the collector plate 300 may be disposed on the first non-coating portion 122 and the second non-coating portion 222 and pressurized, so that the first non-coating portion 122 is substantially completely bent in the first direction, and the second non-coating portion 222 is substantially completely bent in the direction opposite to the first direction. Thus, the connection stability and space utilization of the collector plate 300 and the stacked structure can be improved.

[0179] In some embodiments, the collector plate 300 may include a welding portion 310 , and the welding portion 310 is used to weld the first electrode tab 120 including the first non-coating portion 122 and the second electrode tab 220 including the second non-coating portion 222 .

[0180] For example, the first electrode tab 120 and the second electrode tab 220 may be in contact with the first collector plate 300a and welded by laser welding, thereby forming a welded portion where the top surfaces of the first electrode tab 120 and the second electrode tab 220 and the first collector plate 300a are welded.

[0181] For example, the third electrode tab 130 and the fourth electrode tab 230 may be in contact with the second collector plate 300b and welded by laser welding, thereby forming a welded portion where the top surfaces of the third electrode tab 130 and the fourth electrode tab 230 are welded to the second collector plate 300b.

[0182] The laser welding may include welding commonly used in the art, for example, fillet welding, lap joint welding, and the like.

[0183] In some embodiments, the welding portion 310 may be disposed on the surface of the collector plate 300 adjacent to the first electrode assembly 100 and the second electrode assembly 200. Thus, the electrode tabs 120, 130, 220, 230 can be fully covered by the collector plate 300, thereby improving the process convenience, driving reliability and mechanical stability of the secondary battery.

[0184] Figure 1 The form of the case 500 shown in the figure is an example, and the shape, size and application degree of the first electrode assembly 100 and the second electrode assembly 200 may be deformed according to the structure of the module or the battery pack.

Claims

1. A secondary battery comprising: A first electrode assembly, the first electrode assembly comprising a first electrode tab, the first electrode tab comprising a plurality of first uncoated portions each bent in a first direction; a second electrode assembly, the second electrode assembly being stacked on the first electrode assembly in the first direction, the second electrode assembly comprising a second electrode tab, the second electrode tab comprising a plurality of second uncoated portions each bent in a direction opposite to the first direction; as well as a collector plate, wherein the collector plate completely 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 and the second electrode tab are not arranged on the same line in the first direction.

2. The secondary battery according to claim 1, wherein The first electrode tab and the second electrode tab face each other in a first diagonal direction inclined relative to the first direction.

3. The secondary battery according to claim 1, wherein A length of each of the plurality of first non-coating portions and the plurality of second non-coating portions in the first direction is not more than 0.5 times a width of the collector plate.

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

5.

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

6. The secondary battery according to claim 1, wherein The width direction of the first electrode assembly and the width direction of the second electrode assembly are each the first direction, the length direction of the first electrode assembly and the length direction of the second electrode assembly are each the second direction, and the height direction of the first electrode assembly and the height direction of the second electrode assembly are each the third direction, The length of the first electrode tab in the third direction is less than 0.5 times the length of the first electrode assembly in the third direction. The length of the second electrode tab in the third direction is less than 0.5 times the length of the second electrode assembly in the third direction.

7. The secondary battery according to claim 1, wherein The width direction of the first electrode assembly and the width direction of the second electrode assembly are each the first direction, the length direction of the first electrode assembly and the length direction of the second electrode assembly are each the second direction, and the height direction of the first electrode assembly and the height direction of the second electrode assembly are each the third direction, The shortest distance between the first electrode tab and the second electrode tab is less than the length of the first electrode tab in the third direction, and the shortest distance is less than the length of the second electrode tab in the third direction.

8. The secondary battery according to claim 1, wherein The first electrode assembly includes: the first electrode tab, the first electrode tab protruding from one side of the first electrode assembly; and a third electrode tab, the third electrode tab including a plurality of third uncoated portions protruding from the other side of the first electrode assembly and each bent in the first direction, The second electrode assembly includes: the second electrode tab, which protrudes from one side of the second electrode assembly; and the fourth electrode tab, which includes a plurality of fourth uncoated portions that protrude from the other side of the second electrode assembly and are each bent in a direction opposite to the first direction.

9. The secondary battery according to claim 8, wherein The first electrode tab and the third electrode tab are not arranged on the same line in a second direction perpendicular to the first direction, The second electrode tab and the fourth electrode tab are not arranged on the same line in the second direction.

10. The secondary battery according to claim 9, wherein The first electrode tab and the second electrode tab are opposite to each other in a first diagonal direction inclined relative to the first direction, The second electrode tab and the fourth electrode tab face each other in a second diagonal direction that is inclined relative to the first direction in a direction opposite to the first diagonal direction.

11. The secondary battery according to claim 8, 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 second electrode tab and the fourth electrode tab are arranged on the same line in the second direction.

12. The secondary battery according to claim 11, wherein The first electrode tab and the second electrode tab are opposite to each other in a first diagonal direction inclined relative to the first direction, The second electrode tab and the fourth electrode tab are opposite to each other in the first diagonal direction.

13. The secondary battery according to claim 8, wherein The first electrode tab and the second electrode tab are provided as positive electrode tabs, and the third electrode tab and the fourth electrode tab are provided as negative electrode tabs.

14. The secondary battery according to claim 8, wherein A length of each of the plurality of third non-coating portions and the plurality of fourth non-coating portions in the first direction is not more than 0.5 times a width of the collector plate.

15. The secondary battery according to claim 1, wherein The current collector plate includes a welding portion to which the first electrode tab and the second electrode tab are welded.

16. The secondary battery according to claim 15, wherein The welding portion is disposed on a surface of the collector plate adjacent to the first electrode assembly and the second electrode assembly.

17. The secondary battery according to claim 1, wherein The secondary battery further comprises: a housing accommodating the first electrode assembly and the second electrode assembly; a cover plate that seals the housing; and An electrode terminal is combined with the cover plate and electrically connected to the electrode tab.

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