Secondary battery and method for manufacturing same

Abstract

The invention discloses a secondary battery and a manufacturing method thereof. The secondary battery includes: an electrode assembly including a plurality of electrode plates, each electrode plate including an electrode tab bent toward a central region of the electrode assembly; a current collector welded to the bent electrode tab; and a terminal electrically connected to the current collector.

Description

Technical Field

[0001] The embodiments of this disclosure relate to secondary batteries and methods of manufacturing the same, and more specifically, to secondary batteries having improved electrode terminals welded to current collectors and methods of manufacturing the same. Background Technology

[0002] Unlike primary batteries, which are not designed for recharging, secondary batteries are designed for both charging and discharging. Generally, a secondary battery includes an electrode assembly comprising a positive electrode plate, a negative electrode plate, and a separator. Electrode tabs, to be electrically connected to external terminals, are formed on each of the positive and negative electrode plates. The electrode tabs formed on each electrode plate are assembled together and soldered to a sub-plate or current collector. This soldering process is called laser plate welding (LPW). The sub-plate or current collector is then electrically connected to the external terminals.

[0003] Traditionally, two electrode tabs are formed on each polarity electrode plate. This prevents any electrode tabs from being left unwelded to the current collector during the welding process. In this case, the welding process becomes more complex because there are two electrode tabs, and the corresponding production and material costs are increased.

[0004] The information disclosed in this background section is intended to enhance understanding of the background of this disclosure, and therefore may contain information that does not constitute related (or prior art). Summary of the Invention

[0005] The embodiments disclosed herein are intended to simplify the process of welding electrode terminals and current collectors during secondary battery manufacturing and to improve performance.

[0006] According to an embodiment of the present disclosure, a secondary battery includes: an electrode assembly including a plurality of electrode plates, each of the plurality of electrode plates including an electrode tab bent toward a central region of the electrode assembly; a current collector welded to the bent electrode tab; and a terminal electrically connected to the current collector.

[0007] According to another embodiment of this disclosure, the secondary battery includes: an electrode assembly including a plurality of electrode plates stacked on top of each other, each of the plurality of electrode plates including an electrode tab, each of the electrode tabs being bent toward a central region corresponding to half the width of the electrode assembly in the stacking direction of the electrode plates; a current collector welded to the bent electrode tab; and a terminal electrically connected to the current collector.

[0008] According to another embodiment of this disclosure, a method for manufacturing a secondary battery includes: manufacturing a plurality of electrode plates, each of the plurality of electrode plates including an electrode terminal piece; assembling the plurality of electrode plates to manufacture an electrode assembly; bending each of the electrode terminal pieces toward a central region of the electrode assembly; bringing a current collector into close contact with the bent electrode terminal piece and welding the current collector to the bent electrode terminal piece; and electrically connecting a terminal to the current collector.

[0009] The aspects and features of this disclosure are not limited to those described above, and other aspects and features not specifically mentioned will be clearly understood by those skilled in the art from the following description of this disclosure. Attached Figure Description

[0010] The accompanying drawings illustrate embodiments of the present disclosure and further describe aspects and features of the disclosure together with the detailed description thereof. Therefore, the present disclosure should not be construed as limited to the drawings, wherein:

[0011] Figure 1 This is a top view of a prismatic secondary battery according to some embodiments of the present disclosure.

[0012] Figure 2 It is along Figure 1 The internal cross-sectional view of the secondary battery taken by line I-I' in the diagram;

[0013] Figure 3 yes Figure 2 An exploded view of the electrode assembly in a secondary battery is shown in the figure.

[0014] Figures 4 to 6 This is a view depicting the configuration of a conventional electrode assembly and laser plate welding;

[0015] Figure 7 It is stacked according to some embodiments of this disclosure. Figure 3 A schematic diagram of the electrode assembly of the electrode plate is shown in the figure;

[0016] Figure 8 It is along Figure 7 The cross-sectional view of the current collector welded to the electrode terminal is shown by line A-A'.

[0017] Figure 9 The illustration shows an implementation in which each electrode terminal in the first group and the second group has a different length.

[0018] Figure 10 It is a plan view of the current collector welded to the electrode terminal piece that bends into an arch shape from the outside of the electrode assembly toward the central region;

[0019] Figure 11The illustration shows an electrode assembly of a secondary battery according to some other embodiments of the present disclosure.

[0020] Figure 12 It is an electrode assembly according to some implementation methods along Figure 11 A schematic diagram of the cross-section intercepted by line B-B' in the diagram;

[0021] Figure 13 The illustration shows an implementation in which each electrode terminal in the first group and the second group has a different length.

[0022] Figure 14 This is a perspective view of a secondary battery module in which a secondary battery according to an embodiment of the present disclosure is arranged;

[0023] Figure 15 It includes Figure 14 The diagram shows a perspective view of the secondary battery pack of the secondary battery module; and

[0024] Figure 16 It includes Figure 15 The diagram shows a vehicle with a secondary battery pack. Detailed Implementation

[0025] In the following description, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The terms or words used in this specification and claims are not to be interpreted narrowly according to their ordinary or dictionary meanings, but should be construed as having meanings and concepts consistent with the technical spirit of the present disclosure, based on the principle that the inventor can be his / her own lexicographer to appropriately define the concepts of the terms to best describe his / her invention.

[0026] The embodiments described in this specification and the configurations shown in the accompanying drawings are only some embodiments of this disclosure and do not represent all aspects, features, and embodiments of this disclosure. Accordingly, it should be understood that various equivalents and modifications may exist to replace or modify one or more embodiments or features described herein at the time of filing of this application.

[0027] It should be understood that if an element or layer is described as being "on" another element or layer, "connected to," or "linked to" another element or layer, then it may be directly on, directly connected to, or directly linked to that other element or layer, or one or more intermediary elements or layers may be present. When an element or layer is described as being "directly on" another element or layer, "directly connected to," or "directly linked to" another element or layer, no intermediary element or layer is present. For example, if a first element is described as being "linked" or "connected" to a second element, then the first element may be directly linked or directly connected to the second element, or the first element may be indirectly linked or indirectly connected to the second element via one or more intermediary elements.

[0028] In the figures, the dimensions of various elements, layers, etc., may be enlarged for clarity. The same reference numerals label the same elements. As used herein, the term “and / or” includes any and all combinations of one or more of the associated enumerated items. Furthermore, in describing embodiments of this disclosure, the use of “may” refers to “one or more embodiments of this disclosure.” When expressions such as “at least one of…” and “any one of…” follow a list of elements, they modify the entire list of elements and not individual elements within the list. When phrases such as “at least one of A, B, and C,” “at least one of A, B, or C,” “at least one selected from the group of A, B, and C,” or “at least one selected from A, B, and C” are used to refer to a list of elements A, B, and C, the phrase may refer to any and all suitable combinations or subsets of A, B, and C, such as A, B, C, A and B, A and C, B and C, or A and B and C. As used herein, the term “use” and its variations may be considered synonymous with the term “utilize” and its variations, respectively. As used herein, the terms “substantially,” “approximately,” and similar terms are used as approximate terms and not as terms of degree, and are intended to explain the inherent variations in the measured or calculated values ​​that will be recognized by those skilled in the art.

[0029] It should be understood that although the terms first, second, third, etc., may be used herein to describe various elements, components, regions, layers, and / or portions, these elements, components, regions, layers, and / or portions should not be limited by these terms. These terms are used to distinguish one element, component, region, layer, or portion from another element, component, region, layer, or portion. Therefore, without departing from the teachings of the exemplary embodiments, the first element, first component, first region, first layer, or first portion discussed below may be referred to as a second element, second component, second region, second layer, or second portion.

[0030] For ease of description, spatial relative terms such as “below,” “below,” “down,” “above,” and “above” are used herein to describe the relationship between one element or feature and another illustrated in the figures. It should be understood that, in addition to the orientation depicted in the figures, the spatial relative terms are also intended to encompass different orientations of the device in use or operation. For example, if the device in the figures is flipped, an element described as “below” or “below” other elements or features will be oriented “above” or “above” that other element or feature. Therefore, the term “below” can encompass both above and below orientations. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptors used herein should be interpreted accordingly.

[0031] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. It should be further understood that when the terms “comprising,” “including,” and variations thereof are used in this specification, the term specifies the presence of the described features, numbers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, numbers, steps, operations, elements, components, and / or groups thereof.

[0032] Furthermore, any numerical range disclosed and / or referenced herein is intended to include all subranges with the same numerical precision contained within the referenced range. For example, the range “1.0 to 10.0” is intended to include all subranges between the stated minimum value of 1.0 and the stated maximum value of 10.0 (and inclusive of both), i.e., minimum values ​​greater than or equal to 1.0 and maximum values ​​less than or equal to 10.0, such as, for example, 2.4 to 7.6. Any maximum numerical limit set forth herein is intended to include all lower numerical limits contained therein, and all minimum numerical limits set forth in this specification are intended to include all higher numerical limits contained therein. Accordingly, the applicant reserves the right to amend this specification (including the claims) to expressly set forth any subranges contained within the range expressly set forth herein. All such ranges are intended to be inherently described in this specification such that any amendment to expressly set forth any such subrange will comply with the requirements of patent law.

[0033] Referring to two compared elements, features, etc., as “identical” can mean that they are “substantially identical.” Therefore, the phrase “substantially identical” can include cases with deviations considered low in the art (e.g., approximately 5% or less). Additionally, if a parameter is said to be uniform in a given region, this can mean that it is uniform in terms of average value.

[0034] Throughout the instruction manual, unless otherwise stated, each element may be singular or plural.

[0035] Placing any element "above (or below)" or "above (below)" another element can mean that the arbitrary element can contact the upper (or lower) surface of the element, and that the other element can be located between the element and any element located above (or below) the element.

[0036] Additionally, it should be understood that if a component is referred to as a “link,” “connect,” or “attached” to another component, then these components can be directly “connected,” “linked,” or “attached” to each other, or another component can “intervene” between these components.

[0037] Throughout the specification, unless otherwise stated, when “A and / or B” is mentioned, it means A, B, or A and B. That is, “and / or” includes any or all combinations of the listed items. Unless otherwise stated, when “C to D” is mentioned, it means C or greater and D or less.

[0038] The terminology used herein is for the purpose of describing embodiments of this disclosure and is not intended to limit this disclosure.

[0039] Figure 1 This is a top view of a secondary battery according to some embodiments of the present disclosure.

[0040] First, the appearance of the prismatic secondary battery will be described.

[0041] The housing 51 defines the overall appearance of the prismatic secondary battery and can be made of a conductive metal such as aluminum, aluminum alloy, or nickel-plated steel. Additionally, the housing 51 provides space for housing the electrode assembly therein.

[0042] The cover assembly 60 may include a cover plate 61 that covers the opening of the housing 51. In some embodiments, the housing 51 and the cover plate 61 may be made of a conductive material. Here, the first terminal 62 and the second terminal 63 may be electrically connected to corresponding positive and negative electrodes (or negative and positive electrodes) inside the housing 51 and may be mounted to protrude outward through the cover plate 61.

[0043] The cover plate 61 may have an electrolyte injection port 64 formed to receive a sealing plug (or sealing pin) and a gas vent 65. A venting device (e.g., a gas venting device 66) may be attached to the gas vent 65. The gas venting device 66 opens (e.g., bursts) in response to excess gas generated inside the battery and performs a venting function.

[0044] Figure 2 It is based on some embodiments of this disclosure. Figure 1 The cross-sectional view taken from line I-I'. (Reference) Figure 2 The internal structure of the prismatic secondary battery and its connection structure with the cover assembly 60 will be further described.

[0045] like Figure 2 As shown, the prismatic secondary battery may include an electrode assembly 40, a first current collector 41, a first terminal 62, a second current collector 42, a second terminal 63, a housing 51, and a cover assembly 60.

[0046] Electrode assembly 40 can be formed by winding or stacking a stack of a first electrode plate, a diaphragm, and a second electrode plate, each of which is formed as a thin plate or a thin film. When electrode assembly 40 is a wound stack, the winding axis can be parallel to the longitudinal direction of housing 51. In some embodiments, electrode assembly 40 is a stack type instead of a wound type, but the shape of electrode assembly 40 is not limited in this disclosure. Alternatively, electrode assembly 40 can be a Z-stacked electrode assembly, wherein a positive electrode plate and a negative electrode plate are inserted into both sides of a diaphragm, and then the electrode assembly is bent (or folded) into a Z-stack. Alternatively, one or more electrode assemblies can be stacked such that the long sides of the electrode assemblies are adjacent to each other and housed in a housing, and the number of electrode assemblies in the housing is not limited in this disclosure. The first electrode plate of the electrode assembly can act as a negative electrode, and the second electrode plate can act as a positive electrode. Of course, the reverse is also possible.

[0047] The first electrode plate can be formed by applying a first electrode active material (such as graphite, carbon, etc.) to a first electrode current collector formed of a metal foil (such as copper, copper alloy, nickel, nickel alloy, etc.). The first electrode plate may include a first electrode tab 43 (e.g., a first uncoated portion), where the first electrode tab 14 is a region where the first electrode active material is not applied. The first electrode tab 43 can serve as a current flow path between the first electrode plate and the first current collector 41. In some embodiments, during the manufacture of the first electrode plate, the first electrode tab 43 can be formed by pre-cutting it to protrude to one side of the electrode assembly 40, or the first electrode tab 43 can protrude further (e.g., further or beyond the diaphragm) to one side of the electrode assembly 40 without being separately cut.

[0048] The second electrode plate can be formed by applying a second electrode active material (such as a transition metal oxide) to a second electrode current collector formed of a metal foil (such as aluminum or an aluminum alloy). The second electrode plate may include a second electrode tab 44 (e.g., a second uncoated portion), where the second electrode tab 15 is a region where the second electrode active material is not applied. The second electrode tab 44 can serve as a current flow path between the second electrode plate and the second current collector 42. In some embodiments, during the manufacture of the second electrode plate, the second electrode tab 44 may be formed by being pre-cut to protrude to the other side (e.g., the opposite side) of the electrode assembly 10, or the second electrode tab 44 may protrude further (e.g., further than or beyond the diaphragm) to the other side of the electrode assembly without being separately cut.

[0049] The separator reduces or essentially prevents short circuits between the first and second electrodes while allowing lithium ions to move between them. The separator can be made of, for example, polyethylene membranes, polypropylene membranes, or polyethylene-polypropylene membranes.

[0050] In some embodiments, the electrode assembly 40 is housed together with the electrolyte in a housing 51.

[0051] In the electrode assembly 40, the first current collector 41 and the second current collector 42 can be welded and connected to the first electrode terminal 43 extending from the first electrode plate and the second electrode terminal 44 extending from the second electrode plate, respectively. In some embodiments where the first electrode terminal 43 and the second electrode terminal 44 are located at the top of the electrode assembly 40, the first current collector 41 and the second current collector 42 are located at the top of the electrode assembly 40.

[0052] like Figure 2 As illustrated, the first current collector 41 and the second current collector 42 are respectively connected to the first terminal 62 and the second terminal 63 via connecting members 67. In some embodiments, the connecting members 67 may each have a threaded outer peripheral surface and can be fastened to the first terminal 62 and the second terminal 63 by threaded connection. However, this disclosure is not limited thereto. For example, the connecting members 67 may also be connected to the first terminal 62 and the second terminal 63 by riveting or welding.

[0053] The following will describe suitable materials that can be used in secondary batteries according to embodiments of the present disclosure.

[0054] As the positive electrode active material, compounds capable of reversibly inserting / deintercalating lithium (e.g., lithiation intercalation compounds) can be used. For example, at least one of lithium and a composite oxide of a metal selected from cobalt, manganese, nickel, and combinations thereof can be used.

[0055] The composite oxide can be a lithium transition metal composite oxide, and examples of it can include lithium nickel oxides (i.e., lithium nickel composite oxides), lithium cobalt oxides, lithium manganese oxides, lithium iron phosphate compounds, cobalt-free nickel manganese oxides, or combinations thereof.

[0056] As an example, a compound represented by any of the following formulas can be used: Li a A 1-b X b O 2-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Mn 2-b X b O 4-c D c (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.05); Li a Ni 1-b-c Co b X c O2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni 1-b-c Mn b X c O 2-α D α (0.90≤a≤1.8, 0≤b≤0.5, 0≤c≤0.5, 0<α<2); Li a Ni b Co c L 1 d G e O2(0.90≤a≤1.8, 0≤b≤0.9, 0≤c≤0.5, 0≤d≤0.5, O≤e≤0.1); Li a NiG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a CoG b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-b G b O2(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn2G b O4(0.90≤a≤1.8, 0.001≤b≤0.1); Li a Mn 1-g G g PO4(0.90≤a≤1.8, 0≤g≤0.5); Li (3-f) Fe2(PO4)3 (0≤f≤2); Li a FePO4 (0.90≤a≤1.8).

[0057] In the above formula: A is Ni, Co, Mn or a combination thereof; X is Al, Ni, Co, Mn, Cr, Fe, Mg, Sr, V, rare earth elements or a combination thereof; D is O, F, S, P or a combination thereof; G is Al, Cr, Mn, Fe, Mg, La, Ce, Sr, V or a combination thereof; and L 1 It is Mn, Al, or a combination thereof.

[0058] The positive electrode for a lithium secondary battery may include a substrate and a positive electrode active material layer formed on the substrate. The positive electrode active material layer may include a positive electrode active material and may further include a binder and / or a conductive material.

[0059] Based on 100 wt% of the positive electrode active material layer, the content of the positive electrode active material is in the range of about 90 wt% to about 99 wt%, and based on 100 wt% of the positive electrode active material layer, the contents of the binder and the conductive material are respectively in the range of about 0.5 wt% to about 5 wt%.

[0060] The substrate may be an aluminum (Al) foil, but is not limited thereto.

[0061] The negative electrode active material may include a material capable of reversibly intercalating / deintercalating lithium ions, lithium metal, an alloy of lithium metal, a material capable of doping and dedoping lithium, or a transition metal oxide.

[0062] The material capable of reversibly intercalating / deintercalating lithium ions may be a carbon-based negative electrode active material, which may include, for example, crystalline carbon, amorphous carbon, or a combination thereof. Examples of crystalline carbon may include graphite such as natural graphite or artificial graphite, and examples of amorphous carbon may include soft carbon, hard carbon, pitch carbide, mesophase pitch carbide, sintered coke, etc.

[0063] The Si-based negative electrode active material or the Sn-based negative electrode active material may be used as the material capable of doping and dedoping lithium. The Si-based negative electrode active material may be silicon, a silicon-carbon composite, SiO x (0 < x ≤ 2, for example SiO2), a Si-based alloy, or a combination thereof.

[0064] The silicon-carbon composite may be a composite of silicon and amorphous carbon. According to one embodiment, the silicon-carbon composite may be in the form of silicon particles, and amorphous carbon is coated on the surface of the silicon particles.

[0065] The silicon-carbon composite may further include crystalline carbon. For example, the silicon-carbon composite may include a core containing crystalline carbon and silicon particles and an amorphous carbon coating on the surface of the core.

[0066] The negative electrode for a lithium secondary battery may include a substrate and a negative electrode active material layer provided on the substrate. The negative electrode active material layer may include a negative electrode active material, and may further include a binder and / or a conductive material.

[0067] For example, the negative electrode active material layer may include about 90 wt% to about 99 wt% of the negative electrode active material, about 0.5 wt% to about 5 wt% of the binder, and about 0 wt% to about 5 wt% of the conductive material.

[0068] A non-aqueous binder, an aqueous binder, a dry binder, or a combination thereof may be used as the binder. When an aqueous binder is used as the negative electrode binder, a cellulose-based compound capable of imparting viscosity may be further included.

[0069] As the negative electrode substrate, one can be selected from copper foil, nickel foil, stainless steel foil, titanium foil, nickel foam, copper foam, polymer substrate coated with conductive metal, and combinations thereof.

[0070] Electrolytes used in lithium secondary batteries may include non-aqueous organic solvents and lithium salts.

[0071] Non-aqueous organic solvents act as a medium through which ions participating in the electrochemical reactions of the battery can move.

[0072] Non-aqueous organic solvents can be carbonate solvents, ester solvents, ether solvents, ketone solvents, alcohol solvents, and aprotic solvents, and can be used alone or in combination of two or more.

[0073] In addition, when using carbonate solvents, a mixture of cyclic carbonates and chain carbonates can be used.

[0074] Depending on the type of lithium secondary battery, a separator can be present between the first electrode plate (e.g., the negative electrode) and the second electrode plate (e.g., the positive electrode). As a separator, polyethylene separators, polypropylene separators, polyvinylidene fluoride separators, or multilayer membranes comprising two or more layers thereof can be used.

[0075] The diaphragm may include a porous substrate and a coating on one or both surfaces of the porous substrate, comprising organic materials, inorganic materials, or combinations thereof.

[0076] Organic materials may include polyvinylidene fluoride polymers or (meth)acrylic acid polymers.

[0077] Inorganic materials may include, but are not limited to, inorganic particles selected from Al2O3, SiO2, TiO2, SnO2, CeO2, MgO, NiO, CaO, GaO, ZnO, ZrO2, Y2O3, SrTiO3, BaTiO3, Mg(OH)2, boehmite and combinations thereof.

[0078] Organic and inorganic materials can be mixed in a coating, or they can be in the form of a coating containing (or containing) organic materials and a coating containing (or containing) inorganic materials stacked on top of each other.

[0079] Figure 3 It is contained in Figure 2 An exploded view of the electrode assembly 40 in the secondary battery is shown.

[0080] Figure 3The diagram shows an arrangement of electrode plates and diaphragms in the following order: first first electrode plate 414-1, diaphragm 412, first second electrode plate 416-1, diaphragm 412, second first electrode plate 414-2, diaphragm 412, second second electrode plate 416-2, diaphragm 412, third first electrode plate 414-3, diaphragm 412, third second electrode plate... However, this disclosure is not limited to this arrangement.

[0081] According to some embodiments of this disclosure, the first electrode terminal 43 and the second electrode terminal 44 can be formed on the first electrode plate 414-n (n = 1, 2, 3, ...) and the second electrode plate 416-n, respectively. The first electrode terminal 43 and the second electrode terminal 44 electrically connect the electrode plate to external terminals. To electrically connect each electrode terminal 43 or electrode terminal 44 to external terminals, a sub-board or current collector can be soldered to the electrode terminal 43 or electrode terminal 44 of the electrode plate, and the sub-board or current collector can be connected to external terminals. The above has been referenced... Figure 2 This has been described. The process of welding the electrode terminals 43 or 44 of the electrode plate to the sub-plate or current collector can be called laser plate welding (LPW).

[0082] Figures 4 to 6 It describes the configuration of conventional electrode assemblies and LPWs.

[0083] and Figure 3 The embodiments shown in this disclosure differ from those in conventional electrode plates, such as... Figure 4 As shown, two electrode tabs 18a and 18b are formed on the first electrode plate 14-n (e.g., the positive electrode plate), and similarly, two electrode tabs 20a and 20b are formed on the second electrode plate 16-n (e.g., the negative electrode plate). This prevents any electrode tabs from being missed and not soldered to the current collector during the LPW process (e.g., because the number of electrode plates of each polarity is typically more than 100, there may be unsoldered tabs when soldering more than 100 electrode tabs of each polarity to the current collector).

[0084] like Figure 5 As shown, two electrode terminals 18a and 18b of each polarity or electrode terminals 20a and 20b formed on electrode plates 14-n or 16-n are bent in opposite directions, and a subplate or current collector is placed on the two electrode terminals to perform LPW ( Figure 5 Only electrode terminals 20a and 20b of electrode plate 16-n are shown in the figure.

[0085] Figure 6 This is a plan view illustrating the sub-board or current collector 22 soldered to the electrode terminals. For example... Figure 5As shown, because the two electrode terminals 18a and 18b or electrode terminals 20a and 20b are bent in opposite directions, the ends of the electrode terminals 20a and 20b located on the outer side of the electrode plate protrude beyond the area of ​​the current collector 22, as shown. Figure 6 As shown in the diagram. The ends of the side-protruding electrode tabs 20a and 20b should be folded back towards the current collector and secured with tape. In this structure, where each electrode plate in the existing positive and negative electrode plates includes two electrode tabs, the LPW process is complex and incurs corresponding costs.

[0086] Returning to this public statement, Figure 7 It is stacked according to some embodiments of this disclosure. Figure 3 A schematic diagram of the electrode assembly of the electrode plates is shown. It can be seen that an electrode terminal 43 or electrode terminal 44 is formed for each electrode plate (or within each electrode plate). Although Figure 7 The illustration shows a small number of electrode plates stacked, but in the case of actual products, a much larger number of electrode plates are stacked to form the electrode assembly (e.g., 100 electrode plates stacked for each polarity).

[0087] Figure 8 It is along Figure 7 The cross-sectional view of the current collector welded to the electrode terminal is shown by line A-A'. Figure 8 The diagram shows electrode terminals formed on some polarized electrode plates.

[0088] The secondary battery disclosed herein may include: an electrode assembly comprising a plurality of electrode plates, each of the plurality of electrode plates including an electrode tab bent toward a central region of the electrode assembly. The plurality of electrode tabs, each forming one electrode tab on each electrode plate (e.g., each electrode plate having only one electrode tab), may be substantially divided in half into tab groups 44a and tab groups 44b, and the electrode tabs of each group may be bent into an arch shape toward a central region of the stacked electrode assembly 40 and assembled, and a current collector 42 may be placed on the electrode tabs prior to welding (e.g., see...). Figure 2 Laser welding, friction welding, and ultrasonic welding can be used as welding methods, but this disclosure is not limited thereto. During welding, tools can be used to bring electrode terminals 44a and 44b into close contact with the current collector 42.

[0089] In some implementations, the central region can be... Figure 8 The region corresponding to approximately half the stack width of the stacked electrode assembly 40 shown in the figure. For example, the region adjacent to the longitudinal centerline C of the electrode assembly 40 can be considered as the central region.

[0090] In some implementations, such as Figure 8 As shown, the electrode terminals 44a and 44b of the electrode assembly 40 can be bent into curves to form an arch together, but this disclosure is not limited thereto.

[0091] These electrode terminals can be molded into an arch shape and welded to simplify the manufacturing process of secondary batteries, and in particular, to reduce the number of welding processes or the amount of welding, thereby reducing process costs and improving process stability. Furthermore, because all electrode terminals are bent and assembled towards the central area, the occurrence of welding omissions during the welding of sub-boards or current collectors can be significantly reduced.

[0092] Figure 9 The diagram illustrates an implementation where each electrode contact in the first group and the second group has a different length, such that when the electrode contact 44a of the first group and the electrode contact 44b of the second group are as follows... Figure 8 As shown, when bending towards the central region, the bending of the electrode tabs is performed smoothly and does not create areas of excessive overlap.

[0093] Here, the length of the electrode terminals located on the outer side of the electrode assembly 40 can be greater than the length of the electrode terminals located in the inner region of the electrode plate. For example, the length of the electrode terminals among multiple terminals can gradually decrease towards the central region. Accordingly, as... Figure 9 As shown, the length of the electrode terminals 44a in the first group can gradually decrease towards the longitudinal centerline C, and the length of the electrode terminals 44b in the second group can gradually decrease towards the longitudinal centerline C.

[0094] To form electrode tabs of different lengths for each electrode plate, it is easier to cut the electrode plates using laser grooving instead of traditional die grooving, as the length of the electrode tabs can be set relatively freely during laser grooving. However, grooving using a die can also be used.

[0095] In other embodiments, the electrode terminals 44a of the first group and the electrode terminals 44b of the second group may have the same length. In this embodiment, each electrode plate may form one electrode terminal, and it is possible to achieve an arched shape from both sides of the electrode assembly toward the central region for welding the current collector.

[0096] Figure 10 It is a plan view of the current collector welded to the electrode terminal piece that bends into an arch shape from the outside of the electrode assembly toward the central region. Figure 10 The current collector 42 (e.g., welded to the left side of the upper surface of the electrode assembly 40) is shown. Figure 2 The second current collector in the middle) and the current collector 41 welded to its right (e.g., Figure 2The first current collector in the process. The portions welded to the electrode terminals are indicated by 423 and 413. The connecting member 67 for each current collector in current collectors 42 and 41 is a connecting member connected to an external terminal and has been referenced above. Figure 2 It has been described.

[0097] Figure 11 The figure illustrates an electrode assembly 40' of a secondary battery according to some other embodiments of the present disclosure. The electrode assembly 40' in this embodiment is wound and has a hollow region 45 in the center (as described above). Figure 7 The electrode assembly 40' shown is referred to as a stacked type.

[0098] Multiple electrode terminals, each forming an electrode terminal on each electrode plate, can be roughly divided into terminal group 44a' and terminal group 44b', and the electrode terminals of each group can be bent into an arch shape and assembled toward the central region of the wound electrode assembly 40', and a current collector can be placed on the electrode terminals to perform welding.

[0099] In this embodiment, the central region may be a hollow region 45 located at approximately half the width of the wound electrode assembly 40'. For example, the region adjacent to the hollow region 45 of the wound electrode assembly 40' may be referred to as the central region.

[0100] Figure 12 It is an electrode assembly according to some implementation methods along Figure 11 The schematic cross-sectional view taken by line B-B' in the figure. In the case of the wound electrode assembly, even when the electrode terminals 44a' and 44b' of the electrode plate are the same length, due to the hollow area 45, a gap will be formed between the first group of electrode terminals 44a' and the second group of electrode terminals 44b', and the electrode terminals on both sides can easily be bent into an arch shape.

[0101] Figure 13 The illustration shows an embodiment in which each electrode terminal in the first group and the second group has a different length, such that when the electrode terminal 44a' of the first group and the electrode terminal 44b' of the second group are bent toward the hollow region 45, the bending of the electrode terminal is performed smoothly and no excessive overlap is formed.

[0102] In this embodiment, the length of the electrode terminals located on the outer side of the electrode assembly 40 can be greater than the length of the electrode terminals located in the central region of the electrode plate. For example, the length of the electrode terminals among the plurality of electrode terminals can gradually decrease towards the hollow region 45. Accordingly, as Figure 13As shown, the length of the electrode terminals 44a' in the first group can gradually decrease towards the hollow region 45, and the length of the electrode terminals 44b' in the second group can gradually decrease towards the hollow region 45.

[0103] To form electrode tabs of different lengths for each electrode plate, it is easier to cut the electrode plates using laser grooving instead of traditional die grooving, as the length of the electrode tabs can be set relatively freely during laser grooving. However, grooving using a die can also be used.

[0104] Methods for manufacturing a secondary battery according to some embodiments of the present disclosure will be described. The method for manufacturing a secondary battery according to embodiments of the present disclosure may include manufacturing a plurality of electrode plates, each of the plurality of electrode plates including an electrode terminal piece (e.g., an electrode terminal piece formed on each electrode terminal piece); assembling the plurality of electrode plates to manufacture an electrode assembly; welding a current collector to the electrode terminal piece formed on the electrode plate of the electrode assembly; and electrically connecting terminals to the current collector. Welding the current collector may include bending each electrode terminal piece of the plurality of electrode plates of the electrode assembly toward a central region of the electrode assembly, and bringing the current collector into close contact with the bent electrode terminal piece and welding it to the bent electrode terminal piece.

[0105] In some implementations, bending the electrode tabs may include bending each of the plurality of electrode tabs in the electrode assembly into a curve.

[0106] In some embodiments, assembling multiple electrode plates for manufacturing an electrode assembly may include stacking the multiple electrode plates to manufacture a stacked electrode assembly. In this embodiment, the central region may be a region located at a position corresponding to half the stack width of the stacked electrode assembly.

[0107] In some embodiments, assembling multiple electrode plates for manufacturing an electrode assembly may include winding the multiple electrode plates to manufacture a wound electrode assembly. In this embodiment, the central region may be a hollow region of the wound electrode assembly.

[0108] In some embodiments, manufacturing a plurality of electrode plates on which electrode tabs are formed may include forming the electrode tabs of the plurality of electrode plates to be of the same length. In some other embodiments, manufacturing a plurality of electrode plates on which electrode tabs are formed may include forming electrode tabs of different lengths on the plurality of electrode plates.

[0109] Figure 14This is a perspective view of a secondary battery module in which secondary batteries according to embodiments of the present disclosure are arranged; as the required secondary battery capacity for driving electric vehicles and the like increases, a secondary battery module can be manufactured by arranging multiple secondary battery cells laterally and / or longitudinally and connecting them together. Multiple secondary batteries can be arranged in a space defined by a pair of facing end plates 68a and 68b and a pair of facing side plates 69a and 69b. The secondary batteries can be arranged in a certain orientation and number to obtain desired voltage and current specifications.

[0110] Figure 15 This is a perspective view of a battery pack 70 according to an embodiment of the present disclosure. Reference Figure 15 The battery pack 70 may include components electrically connected to individual batteries and a battery pack housing housing the components. For ease of illustration, components including busbars, cooling units, external terminals for electrically connecting the batteries, etc., are not shown in the accompanying drawings.

[0111] The battery pack 70 can be installed on (or in) a vehicle. The vehicle can be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle can be a four-wheeled vehicle or a two-wheeled vehicle, but is not limited thereto. Figure 16 In the lower part of the vehicle body including Figure 15 The diagram shows a vehicle with battery pack 70. The vehicle can operate by receiving power from battery pack 70 (e.g., it can be powered by receiving power from battery pack 70).

[0112] According to embodiments of this disclosure, electrode terminals formed on the electrode plate for each polarity can be bent into an arch shape and welded to simplify the secondary battery manufacturing process, and in particular, to reduce the number of welding processes or the amount of welding, thereby reducing process costs and ensuring process stability. Furthermore, because all electrode terminals are bent and assembled together towards the central region, the occurrence of welding omissions during the welding of sub-plates or current collectors can be significantly reduced.

[0113] Although the present disclosure has been described above with respect to its embodiments, the present disclosure is not limited thereto. Various modifications and variations may be made thereto by those skilled in the art within the spirit of the present disclosure as defined by the appended claims and their equivalents.

Claims

1. A secondary battery, comprising: An electrode assembly includes a plurality of electrode plates, each of the plurality of electrode plates including an electrode tab bent toward a central region of the electrode assembly; The current collector is welded to the bent electrode terminal piece; and The terminal is electrically connected to the current collector.

2. The secondary battery according to claim 1, wherein each electrode terminal is bent into a curve.

3. The secondary battery according to claim 1, wherein the electrode assembly is a stacked electrode assembly.

4. The secondary battery according to claim 3, wherein the central region corresponds to half the stacking width of the stacked electrode assembly.

5. The secondary battery according to claim 1, wherein the electrode assembly is a wound electrode assembly.

6. The secondary battery according to claim 5, wherein the central region is the hollow region of the wound electrode assembly.

7. The secondary battery according to any one of claims 1 to 6, wherein the electrode terminals are of the same length.

8. The secondary battery according to any one of claims 1 to 6, wherein the electrode terminals have different lengths from one another, and The length of the electrode terminal piece on the outer side of the electrode assembly is greater than the length of the electrode terminal piece in the central region of the electrode assembly.

9. A secondary battery, comprising: An electrode assembly includes a plurality of electrode plates stacked on top of each other, each of the plurality of electrode plates including an electrode tab, each of the electrode tabs being bent toward a central region corresponding to half the width of the electrode assembly in the stacking direction of the electrode plates; The current collector is welded to the bent electrode terminal piece; and The terminal is electrically connected to the current collector.

10. The secondary battery according to claim 9, wherein each electrode terminal is bent into a curve.

11. The secondary battery according to claim 9 or 10, wherein the lengths of the electrode terminals are different from each other.

12. The secondary battery of claim 11, wherein the length of the electrode terminal piece at the outer side of the electrode assembly is greater than the length of the electrode terminal piece at the central region of the electrode assembly.

13. A method for manufacturing a secondary battery, the method comprising: A plurality of electrode plates are manufactured, each of the plurality of electrode plates including an electrode terminal piece; Assemble the plurality of electrode plates to manufacture an electrode assembly; Each electrode terminal in the electrode terminal is bent toward the central region of the electrode assembly; The current collector is brought into close contact with the bent electrode tab, and the current collector is welded to the bent electrode tab; and Connect the terminals electrically to the current collector.

14. The method of claim 13, wherein the bending of the electrode tabs comprises bending each of the electrode tabs into a curve.

15. The method of claim 13, wherein the assembly of the plurality of electrode plates comprises stacking the plurality of electrode plates to manufacture a stacked electrode assembly.

16. The method of claim 15, wherein the central region is a region corresponding to half the stack width of the stacked electrode assembly.

17. The method of claim 13, wherein the assembly of the plurality of electrode plates includes winding the plurality of electrode plates to manufacture a wound electrode assembly.

18. The method of claim 17, wherein the central region is the hollow region of the wound electrode assembly.

19. The method of claim 13, wherein the manufacturing of the plurality of electrode plates comprises forming the lengths of the electrode tabs of the plurality of electrode plates to be the same as each other.

20. The method of claim 13, wherein the manufacturing of the plurality of electrode plates includes forming the lengths of the electrode tabs of the plurality of electrode plates to be different from each other.

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