Secondary battery

Abstract

A secondary battery according to one aspect of the present invention may comprise: a case; a plurality of electrode assemblies accommodated in the case and each including a first electrode, a separator, and a second electrode; a first electrode tab coupled to the first electrode; a second electrode tab coupled to the second electrode; a first current collector plate coupled to the first electrode tab; a second current collector plate coupled to the second electrode tab; and a cap assembly which seals the case and in which a first terminal and a second terminal respectively connected to the first current collector plate and the second current collector plate are positioned, wherein the first current collector plate has a first cutout portion into which at least a portion of the first electrode tab is inserted.

Description

secondary battery

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

[0002] Recently, as the demand for portable electronic products such as laptops, video cameras, and mobile phones has rapidly increased, and the development of electric vehicles, energy storage batteries, robots, and satellites has been in full swing, research on high-performance secondary batteries capable of repeated charging and discharging is actively being conducted.

[0003] Currently commercially available secondary batteries include nickel-cadmium batteries, nickel-metal hydride batteries, nickel-zinc batteries, and lithium secondary batteries. Among these, lithium secondary batteries are attracting attention for their advantages, including virtually no memory effect compared to nickel-based batteries, free charging and discharging, a very low self-discharge rate, and high energy density.

[0004] These lithium secondary batteries primarily use lithium oxide and carbon materials as the positive and negative electrode active materials, respectively. Furthermore, the lithium secondary battery comprises a positive electrode plate and a negative electrode plate coated with the positive and negative electrode active materials, an electrode assembly in which the positive and negative electrode plates are positioned with a separator between them, and an outer case that seals and houses the electrode assembly together with an electrolyte.

[0005] Meanwhile, lithium secondary batteries can be classified into can-type secondary batteries, in which the electrode assembly is housed in a metal can, and pouch-type secondary batteries, in which the electrode assembly is housed in a pouch made of aluminum laminate sheet, depending on the shape of the battery case. Can-type secondary batteries can be further classified into cylindrical batteries and square batteries, depending on the shape of the metal can.

[0006] For square batteries, multiple thin-film tabs connected to the electrode plates are assembled into a single, pre-welded assembly, then re-welded to the current collector. As the electrode assembly thickness increases, the length of the thin-film tabs required for pre-welding increases. Furthermore, the space occupied by the pre-welded thin-film tabs within the square battery increases, making it difficult to increase the energy density per unit volume of the battery.

[0007] Additionally, as current reaches the electrode assembly through the external terminal, resistance may increase as the length of the thin film tab, etc., increases.

[0008] In order to solve the above problem, an object of the present invention is to provide a secondary battery capable of increasing energy density per unit volume by reducing the space occupied by a thin film tab, etc., inside a case.

[0009] Another object of the present invention is to provide a secondary battery capable of reducing resistance to current as the length of a thin film tab increases during the process in which current reaches an electrode assembly through an external terminal.

[0010] Another object of the present invention is to provide a secondary battery that can prevent an increase in cost and an increase in manufacturing time due to an increase in parts during the process of manufacturing a secondary battery.

[0011] According to one aspect of the present invention, a secondary battery comprises a case, a plurality of electrode assemblies accommodated in the case, each electrode assembly including a first electrode, a separator, and a second electrode, a first electrode tab coupled to the first electrode, a second electrode tab coupled to the second electrode, a first current collector plate coupled to the first electrode tab, a second current collector plate coupled to the second electrode tab, a cap assembly sealing the case and having a first terminal and a second terminal respectively connected to the first current collector plate and the second current collector plate, wherein a first cutout portion may be formed in the first current collector plate into which at least a portion of the first electrode tab is inserted.

[0012] The first electrode tab inserted into the first incision can contact the upper surface of the first collector plate.

[0013] The first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies may be in contact with the upper surface of the first current collector plate and may be tilted in opposite directions.

[0014] At the lower portion of the first collector plate, the first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies can be tilted in opposite directions.

[0015] At the lower portion of the first collector plate, the first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies can be inclined to face each other.

[0016] The first electrode tab of one of the pair of electrode assemblies may be tilted in opposite directions, with the first electrode tab positioned above and the first electrode tab positioned below relative to the first collector plate.

[0017] The first electrode tabs of each of the pair of electrode assemblies may be positioned in the same row.

[0018] The first electrode tabs of each of the pair of electrode assemblies may be positioned in different columns.

[0019] The above first cut portion may be formed by cutting a portion of a side surface of the first collector plate.

[0020] The above first cut portion may have a cross-section that is perpendicular to the upper surface of the first collector plate.

[0021] The above first incision may have an inclined cross-section.

[0022] The above first incision may have an arc-shaped cross-section.

[0023] Facing sides of the pair of electrode assemblies may be positioned below the first cutout.

[0024] The remaining end of the first electrode tab may be in line contact with the lower surface of the first collector plate.

[0025] The above first electrode tab can be joined to the first collector plate by welding.

[0026] The first electrode tabs may have the same length.

[0027] A second cutout may be formed in the second collector plate into which at least a portion of the second electrode tab is inserted.

[0028] The second electrode tab inserted into the second cut portion can contact the upper surface of the second collector plate.

[0029] At the lower portion of the second collector plate, the second electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies can be inclined to face each other.

[0030] The above electrode assembly may be stacked or wound.

[0031] As described above, according to one aspect of the present invention, the space occupied by the thin film tab or the like inside the case can be reduced, thereby increasing the energy density per unit volume.

[0032] In addition, according to one aspect of the present invention, in the process of current reaching the electrode assembly through the external terminal, resistance to current can be reduced due to an increase in the length of the thin film tab.

[0033] In addition, according to one aspect of the present invention, it is possible to prevent an increase in cost and an increase in manufacturing time due to an increase in parts in the process of manufacturing a secondary battery.

[0034] FIG. 1 is a perspective view illustrating a secondary battery according to a first embodiment of the present invention.

[0035] Fig. 2 is a perspective view showing a partially disassembled configuration of the secondary battery of Fig. 1.

[0036] Figure 3 is a perspective view showing a state in which the electrode assembly and the first and second collector plates are combined.

[0037] Figure 4 is a cross-sectional view taken along line IV-IV of Figure 3.

[0038] Figure 5 is an enlarged view of area A of Figure 3.

[0039] Figure 6 is a drawing of Figure 5 viewed from above.

[0040] FIG. 7 is a perspective view illustrating a first current collector plate of a secondary battery according to a first embodiment of the present invention.

[0041] Figures 8 to 11 are modified examples of the electrode assembly of Figure 7.

[0042] FIG. 12 is a drawing of an electrode assembly of a secondary battery according to a first embodiment of the present invention viewed from above.

[0043] Figure 13 is a drawing showing a state before the first collector plate is coupled to the first electrode tab of the electrode assembly.

[0044] FIG. 14 is a drawing showing a state in which an electrode assembly and a first current collector plate of a secondary battery according to a second embodiment of the present invention are combined.

[0045] Fig. 15 is a drawing showing the electrode assembly of Fig. 14 cut in the width direction.

[0046] Fig. 16 is a modified example of the first collector plate of Fig. 14.

[0047] Figure 17 is a drawing showing the electrode assembly of Figure 16 cut in the width direction.

[0048] FIG. 18 is a drawing showing a state in which an electrode assembly and a first current collector plate of a secondary battery according to a third embodiment of the present invention are combined.

[0049] Figure 19 is a drawing of Figure 18 viewed from above.

[0050] FIG. 20 is a drawing showing a state in which an electrode assembly and a first collector plate of a secondary battery according to a fourth embodiment of the present invention are combined.

[0051] Figures 21 and 22 are modified examples of the secondary battery illustrated in Figure 20.

[0052] FIG. 23 is a drawing illustrating a first electrode tab of an electrode assembly of a secondary battery according to a fifth embodiment of the present invention.

[0053] Fig. 24 is a perspective view showing a first collector plate of a secondary battery according to a sixth embodiment of the present invention.

[0054] Fig. 25 is a perspective view illustrating a battery module including the secondary battery of Fig. 1.

[0055] FIG. 26 is a perspective view illustrating a battery pack including the battery module of FIG. 23.

[0056] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the detailed description. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0057] The terminology used herein is merely used to describe specific embodiments and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In the present invention, it should be understood that the terms "comprise" or "have" are intended to specify the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but do not exclude in advance the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

[0058] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Please note that, where possible, identical components are represented by identical reference numerals throughout the drawings. Furthermore, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. For the same reason, some components in the attached drawings are exaggerated, omitted, or schematically depicted.

[0059] Hereinafter, a secondary battery according to the first embodiment of the present invention will be described.

[0060] FIG. 1 is a perspective view illustrating a secondary battery according to a first embodiment of the present invention, FIG. 2 is a perspective view illustrating a state in which a part of the secondary battery of FIG. 1 is disassembled, and FIG. 3 is a perspective view illustrating a state in which an electrode assembly and first and second current collector plates are combined.

[0061] Referring to FIGS. 1 to 3, a secondary battery (10) according to a first embodiment of the invention includes an electrode assembly (300) having a separator (316) interposed between a first electrode (317) and a second electrode (319), a first collector plate (510) and a second collector plate (530) electrically connected to the electrode assembly (300), a case (100) in which the electrode assembly (300) is accommodated, and a cap assembly (700) sealing the case (100).

[0062] The electrode assembly (300) may be composed of a plurality of electrode assemblies including a first electrode assembly (310) and a second electrode assembly (330). In the present embodiment, the electrode assembly (300) is described as including two electrode assemblies, but is not necessarily limited thereto and may include three or more electrode assemblies.

[0063] Each of the first electrode assembly (310) and the second electrode assembly (330) may be formed by interposing a separator (316) between the first electrode (317) and the second electrode (319) that are alternately arranged. That is, the separator (316) may be positioned between the first electrode (317) and the second electrode (319), so that the first electrode (317), the separator (316), the second electrode (319), and the separator (316) may be alternately stacked in this order to form the first electrode assembly (310) and the second electrode assembly (330). Here, the first electrode (317) and the second electrode (319) may be an anode and a cathode, respectively, and conversely, the first electrode (317) and the second electrode (319) may be electrodes having different polarities, such as a cathode and an anode, respectively.

[0064] The first electrode (317) and the second electrode (319) may include an electrode active portion (312, 314), which is a region where an active material is applied to a thin plate formed of a metal foil, and an electrode tab (311, 315), which is a region where an active material is not applied. In the present embodiment, the first electrode assembly (310) and the second electrode assembly (330) may have the same structure.

[0065] The first electrode active portion (312) may be formed by applying an active material such as a transition metal oxide to a metal foil such as aluminum, and the second electrode active portion (314) may be formed by applying an active material such as graphite or carbon to a metal foil such as copper or nickel.

[0066] The first electrode tab (311, 331) may protrude toward one side of the first electrode active portion (312), and the second electrode tab (315, 335) may protrude toward one side of the second electrode active portion (314). At this time, the first electrode tab (311, 331) and the second electrode tab (315, 335) may protrude in parallel toward the cap assembly (700). Alternatively, the first electrode tab (311, 331) and the second electrode tab (315, 335) may protrude in different directions.

[0067] The first electrode tab (311, 331) and the second electrode tab (315, 335) are formed by cutting so as to protrude from the metal foil, so that they can be formed integrally with the metal foil of the first electrode active portion (312) and the second electrode active portion (314), respectively.

[0068] The first electrode tab (311, 331) and the second electrode tab (315, 335) can be spaced apart from each other with different polarities.

[0069] Each of the first electrode tabs (311, 331) and the second electrode tabs (315, 335) of the electrode assembly (300) is formed by overlapping a plurality of thin films, and can be connected so that the thin films come into contact with each other by ultrasonic welding, laser welding, or the like to facilitate the movement of current.

[0070] The separator (316) is positioned between the first electrode (317) and the second electrode (319), more specifically between the first electrode active portion (312) and the second electrode active portion (314), to prevent short-circuiting between them and to enable the movement of ions. For example, the separator (316) can be made of various materials, such as polyethylene, polypropylene, or a composite film thereof.

[0071] In this embodiment, the electrode assembly (300) may be formed by winding the first electrode (317) and the second electrode (319) (winding type), or may be formed by overlapping the first electrode (317) and the second electrode (319) in parallel with each other (stack type).

[0072] Meanwhile, the first electrode assembly (310) and the second electrode assembly (330) can be electrically connected to each other.

[0073] The electrode tabs of the same polarity of the first electrode assembly (310) and the second electrode assembly (330) can be electrically connected by the current collector plate (500). Specifically, the first electrode tab (311) of the first electrode assembly (310) and the first electrode tab (331) of the second electrode assembly (330) can be electrically connected by the first current collector plate (510), and the second electrode tab (315) of the first electrode assembly (310) and the second electrode tab (335) of the second electrode assembly (330) can be electrically connected by the second current collector plate (530).

[0074] The first collector plate (510) can electrically connect the first terminal (710) exposed to the outside of the cap assembly (700) and the first electrode tab (311, 331), and the second collector plate (530) can electrically connect the second terminal (730) exposed to the outside of the cap assembly (700) and the second electrode tab (315, 335).

[0075] One side of the first collector plate (510) may be connected to the first electrode tab (311, 331), and the other side of the first collector plate (510) may be connected to the first terminal (710). At this time, the first collector plate (510) may be directly connected to the first terminal (710), or may be indirectly connected to the first terminal (710) through a first connection terminal (511), etc.

[0076] One side of the second collector plate (530) may be connected to the second electrode tab (315, 335), and the other side of the second collector plate (530) may be connected to the second terminal (730). At this time, similar to the first collector plate (510), the second collector plate (530) may be directly connected or indirectly connected to the second terminal (730) through a second connection terminal (531), etc.

[0077] The specific structures of the first collector plate (510) and the second collector plate (530) and the specific bonding structures of each of the first electrode tabs (311, 331) and the second electrode tabs (315, 335) will be described later.

[0078] The cap assembly (700) seals the opening of the case (100) in which the electrode assembly (300) is accommodated, and may include a cap plate (750), a first terminal (710), and a second terminal (730).

[0079] The cap plate (750) may be a plate shape that covers the opening of the case (100). The cap plate (750) may have a shape corresponding to the shape of the opening of the case (100). The cap plate (750) may be formed of the same material as the case (100), and the cap plate (750) may be fixed to the case (100) by laser welding.

[0080] The cap plate (750) may be formed with an electrolyte injection port (770) for injecting an electrolyte, a first terminal hole (711) into which a first connection terminal (511) is inserted, a second terminal hole (731) into which a second connection terminal (531) is inserted, and a vent hole (740) that opens when the pressure inside the case (100) exceeds a predetermined pressure value. However, the position of the vent hole (740) is not necessarily limited thereto, and may be formed on one side of the case (100), for example, on the side or bottom surface of the case (100).

[0081] The first terminal (710) and the second terminal (730) may be formed to protrude from the cap plate (750). The first terminal (710) may be electrically connected to the first electrode (317) through the first collector plate (510), and the second terminal (730) may be electrically connected to the second electrode (319) through the second collector plate (530). At this time, the first terminal (710) may be electrically connected to the first collector plate (510) through the first connection terminal (511), and the second terminal (730) may also be electrically connected to the second collector plate (530) through the second connection terminal (531).

[0082] The first terminal (710) and the second terminal (730) may be formed in a plate shape having a circular or rectangular shape. The first terminal (710) and the second terminal (730) may be connected to a bus bar or the like.

[0083] A first insulating member (715) is arranged between the first terminal (710) and the cap plate (750), so that the first terminal (710) and the cap plate (750) can be insulated from each other. In addition, a second insulating member (735) is arranged between the second terminal (730) and the cap plate (750), so that the second terminal (730) and the cap plate (750) can be insulated from each other.

[0084] The first connecting terminal (511) is inserted into the first terminal hole (711) in a pillar shape, so as to electrically connect the first terminal (710) and the first collector plate (510). Similarly to the first connecting terminal (511), the second terminal (730) is inserted into the second terminal hole (731) in a pillar shape, so as to electrically connect the second terminal (730) and the second collector plate (530).

[0085] The case (100) forms the exterior of the secondary battery (10), and has a space formed therein to accommodate an electrode assembly (300), and an opening may be formed on one side. The case (100) may have a rectangular parallelepiped shape and may be made of a sturdy material capable of protecting the electrode assembly (300) accommodated therein. For example, the case (100) may be made of a metal such as aluminum or stainless steel.

[0086] An electrolyte may be accommodated together with an electrode assembly (300) inside the case (100). The electrolyte may be composed of a lithium salt such as LiPF6 or LiBF4 in an organic solvent such as EC, PC, DEC, EMC, or DMC. The electrolyte may be liquid, solid, or gel-like.

[0087] Meanwhile, a battery module (M) can be configured by including a plurality of secondary batteries (10) according to the present embodiment (see FIG. 25). The plurality of secondary batteries (10) can be connected to each other by bus bars (B) or the like to configure a battery module (M). In addition, a battery pack (P) can be configured by including a plurality of battery modules (M) (see FIG. 26). The battery pack (P) can be configured by arranging a plurality of battery modules (M) in an upper pack housing (VC) and a lower pack housing (LC) that configure a pack housing (C). In addition, the battery pack (P) can be provided to a means of transportation that moves or works while moving loads, people, etc. Such means of transportation can include a bicycle, heavy equipment, agricultural / fishing equipment, automobiles, buses, airplanes, etc. Here, the automobile can be an electric automobile, a hybrid automobile, or a plug-in hybrid automobile. The automobile can include a four-wheeled or two-wheeled automobile. The means of transportation can operate by receiving power from the battery pack (P).

[0088] Fig. 4 is a cross-sectional view taken along line IV-IV of Fig. 3, Fig. 5 is an enlarged view of area A of Fig. 3, and Fig. 6 is a top view of Fig. 5. Fig. 7 is a perspective view showing a first collector plate of a secondary battery according to a first embodiment of the present invention, and Figs. 8 to 11 are modified examples of the electrode assembly of Fig. 7. Fig. 12 is a top view of an electrode assembly of a secondary battery according to a first embodiment of the present invention, and Fig. 13 is a view showing a state before the first collector plate is coupled to the first electrode tab of the electrode assembly.

[0089] Referring to FIGS. 4 to 7, according to the present embodiment, at least some of the plurality of first electrode tabs (311) are inserted into the first cutout (540) of the first collector plate (510), and the remaining some of the plurality of first electrode tabs (311) are positioned at the lower portion of the first collector plate (510) and come into contact with the lower surface of the first collector plate (510).

[0090] At this time, among the plurality of first electrode tabs (311), the first electrode tab (311) adjacent to the first electrode tab (331) can be inserted into the first cutout (540) of the first current collector plate (510). Preferably, the first electrode tab (311) inserted into the first cutout (540) penetrates the first cutout (540) and contacts the upper surface of the first current collector plate (510).

[0091] Meanwhile, similar to the first electrode tab (311), at least some of the plurality of first electrode tabs (331) are inserted into the first cutout (540) of the first collector plate (510), and the remaining some of the plurality of first electrode tabs (331) are positioned below the first collector plate (510) and come into contact with the lower surface of the first collector plate (510).

[0092] At this time, among the plurality of first electrode tabs (331), the first electrode tab (331) adjacent to the first electrode tab (311) can be inserted into the first cutout (540) of the first current collector plate (510). Preferably, the first electrode tab (331) inserted into the first cutout (540) penetrates the first cutout (540) and contacts the upper surface of the first current collector plate (510).

[0093] The first cut portion (540) has a shape in which the side of the first collector plate (510) is cut, and the first cut portion (540) may have inner surfaces (541, 543) facing each other. The first electrode tab (311) and the first electrode tab (331) inserted into the first cut portion (540) penetrate the first collector plate (510) along the inner surfaces (541, 543), respectively. That is, the first electrode tab (311) penetrates the first collector plate (510) along the first inner surface (541), and the first electrode tab (331) penetrates the first collector plate (510) along the second inner surface (543).

[0094] At this time, the plurality of first electrode tabs (311) of the first electrode assembly (310) and the plurality of first electrode tabs (331) of the second electrode assembly (330), which are located below the first collector plate (510), may be inclined in opposite directions. In the present embodiment, the first electrode tabs (311) of the first electrode assembly (310) and the first electrode tabs (331) of the second electrode assembly (330) are described as being plural, but in some cases, at least one of the first electrode tabs (311) and the second electrode tabs (331) may be singular.

[0095] More specifically, the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) located under the first current collector (510) can be inclined to face each other. As illustrated in FIG. 4, the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) under the first current collector (510) can be inclined toward an area where the sides of the first electrode assembly (310) and the second electrode assembly (330) meet. That is, the plurality of first electrode tabs (311) can be inclined toward the plurality of first electrode tabs (331), and the plurality of first electrode tabs (331) can be inclined toward the plurality of first electrode tabs (311). In the present embodiment, the inclination of the electrode tabs includes all states in which the electrode tabs are biased to one side, such as being bent, curved, laid down, or bent to one side.

[0096] At this time, the angle formed by each of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) with the upper surfaces of the first electrode assembly (310) and the second electrode assembly (330) may be 0 to 50 degrees. Accordingly, the gap between the first current collector (510) and the first electrode assembly (310) and the second electrode assembly (330) can be minimized. In addition, through this, the size of the secondary battery (10) can be reduced, and the size of the battery module and battery pack including the plurality of secondary batteries can also be reduced. The energy density per unit volume of the secondary battery can also be increased.

[0097] Meanwhile, the first electrode tab (311) and the first electrode tab (331) located on the upper surface of the first collector plate (510) are inclined in opposite directions. Specifically, the first electrode tab (311) penetrating the first cut portion (540) of the first collector plate (510) faces the outside of the first electrode assembly (310), and the first electrode tab (331) penetrating the first cut portion (540) faces the outside of the second electrode assembly (330). Here, the outside of the first electrode assembly (310) and the second electrode assembly (330) means the opposite direction to the side where the first electrode assembly (310) and the second electrode assembly (330) meet each other.

[0098] In addition, in the present embodiment, with respect to the first collector plate (510), the first electrode tab (311) located on the upper side of the first collector plate (510) and the first electrode tab (311) located on the lower side of the first collector plate (510) can be tilted in opposite directions. As in FIG. 4, the first electrode tab (311) located on the lower side of the first collector plate (510) is tilted toward the second electrode assembly (330), and the first electrode tab (311) located on the upper side of the first collector plate (510) is tilted toward the outer side of the first electrode assembly (310).

[0099] As with the first electrode tab (311), the first electrode tab (331) located on the upper side of the first collector plate (510) and the first electrode tab (331) located on the lower side of the first collector plate (510) can be tilted in opposite directions with respect to the first collector plate (510). The first electrode tab (331) located on the lower side of the first collector plate (510) is tilted toward the first electrode assembly (310), and the first electrode tab (331) located on the upper side of the first collector plate (510) is tilted toward the outer side of the second electrode assembly (330).

[0100] A first current collector plate (510) may be coupled to the upper portion of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331). That is, a plurality of first electrode tabs (311) and a plurality of first electrode tabs (331) may be coupled to the lower portion of the first current collector plate (510). At this time, under the first current collector plate (510), the first electrode tabs (311) and the first electrode tabs (331) are brought into line contact with the lower surface of the first current collector plate (510). Specifically, the ends of the first electrode tabs (311) and the first electrode tabs (331) in the form of a thin film are welded to the lower surface of the first current collector plate (510) in a line contact state.

[0101] Accordingly, the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) can be connected to the first terminal (710) through one first current collector plate (510). In addition, the plurality of second electrode tabs (315) and the plurality of second electrode tabs (335) can be connected to the second terminal (730) through one second current collector plate (530).

[0102] The first collector plate (510), the plurality of first electrode tabs (311), and the plurality of first electrode tabs (331) can be joined to each other by welding. Laser welding, ultrasonic welding, etc. can be applied as the welding.

[0103] A plurality of first electrode tabs (311) and a plurality of first electrode tabs (331) are joined to the lower portion of the first collector plate (510) while tilted in a direction facing each other, and a plurality of welding lines can be formed on the upper surface of the first collector plate (510). That is, by irradiating a laser on the upper surface of the first collector plate (510), the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) located on the lower surface and the lower portion of the first collector plate (510) can be joined to each other. Thereafter, the first electrode tab (311) and the first electrode tab (331) penetrating the first cut portion (540) are pressed against the upper surface of the first collector plate (510), and additionally, a laser is irradiated to bond the first electrode tab (311) and the first electrode tab (331) penetrating the first cut portion (540) of the first collector plate (510) to the upper surface of the first collector plate (510).

[0104] In this embodiment, the structure and bonding method of the second electrode tab (315, 335) are the same as those of the first electrode tab (311, 331), so the description of the second electrode tab (315, 335) will be omitted.

[0105] As shown in FIGS. 6 and 7, the first collector plate (510) may have a flat plate shape at the bottom to facilitate welding with the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331). Accordingly, the upper surfaces of the first collector plate (510) and the first electrode assembly (310) and the second electrode assembly (330) can maintain a constant gap. In addition, the first collector plate (510) and the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) can be uniformly welded and joined.

[0106] At this time, the first collector plate (510) includes a first cut portion (540) formed by cutting a portion of a side surface of the first collector plate (510). The first cut portion (540) may be formed by cutting a portion of a side surface of the plate-shaped first collector plate (510). At this time, the first inner side surface (541) and the second inner side surface (543) of the first cut portion (540) may have a vertical cross-section. The first inner side surface (541) and the second inner side surface (543) have a cross-section that is perpendicular to the upper surface of the first collector plate (510).

[0107] The first collector plate (510) extends along the width direction of the first electrode assembly (310) and the second electrode assembly (330) that are arranged parallel to each other, and the facing sides of the first electrode assembly (310) and the second electrode assembly (330) can be positioned below the first cutout (540).

[0108] A first connection terminal (511) electrically connected to a first terminal (710) may be coupled to the upper surface of the first current collector plate (510). The first connection terminal (511) may be formed integrally with the first current collector plate (510) in a pillar shape. The first connection terminal (511) may be positioned approximately at the center of the first current collector plate (510). Side surfaces of the first electrode assembly (310) and the second electrode assembly (330) facing each other may be positioned below the first connection terminal (511). In the present embodiment, the structure of the second current collector plate (530) is the same as that of the first current collector plate (510), and therefore, a description of the second current collector plate (530) will be omitted.

[0109] Figures 8 to 11 are modified examples of the electrode assembly of Figure 7.

[0110] Referring to FIGS. 8 to 11, the inner surface (541, 543) of the first cut portion (540) of the first collector plate (510) may have various cross-sectional shapes. The cross-sectional shape of the inner surface (541, 543) may have various shapes, such as an inclined cross-section, an arc-shaped cross-section, and a wedge-shaped cross-section with respect to the upper surface of the first collector plate (510). In this way, when the cross-section of the inner surface (541, 543) has the shape as described above, even if the length of the first electrode tab (311, 331) inserted into the first cut portion (540) is short, the area of ​​the inner surface (541, 543) of the first cut portion (540) increases, so that the bonding force between the first electrode tab (311, 331) and the first collector plate (510) can be increased.

[0111] As shown in Fig. 12, when the first electrode assembly (310) and the second electrode assembly (330) are viewed from above, the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are inclined toward the center. Here, the direction of the arrow indicates the direction in which the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are inclined. At this time, the plurality of second electrode tabs (315) and the plurality of second electrode tabs (335) are also inclined toward the center in the same way as the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331).

[0112] At this time, in the present embodiment, the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) may be arranged in a row. The plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) may be arranged in a row along the width direction of the first electrode assembly (310) and the second electrode assembly (330).

[0113] As with the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331), the plurality of second electrode tabs (315) and the plurality of second electrode tabs (335) may also be arranged in a row.

[0114] As illustrated in FIG. 13, before being coupled to the first collector plate (510), the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are vertically aligned with respect to the upper surfaces of the first electrode assembly (310) and the second electrode assembly (330). Thereafter, a pressing plate (not shown) moves toward the side surfaces of each of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331), thereby tilting the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) so as to face each other. In the pressed state, the first collector plate (510) can be welded to the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331). The second collector plate (530), the plurality of second electrode tabs (315), and the plurality of second electrode tabs (335) can also be coupled in the same manner.

[0115] The length of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) may be 10 mm or less. Here, the length of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) means the length when the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are vertically aligned.

[0116] Due to the above lengths of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331), the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) can be directly coupled to the lower portion of the first collector plate (510). If the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are longer than the above lengths, as in FIG. 4, when the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) are tilted and then welded to the first collector plate (510), some of the plurality of first electrode tabs (311) and the plurality of first electrode tabs (331) may not be welded. When the length is long, some of the first electrode tabs (311) and the first electrode tabs (331) press against other first electrode tabs (311) and the first electrode tabs (331), so that the pressed first electrode tabs (311) and the first electrode tabs (331) do not come into contact with the lower portion of the first current collector (510).

[0117] In addition, in order to solve the problem of welding not being performed beyond the above-mentioned length range, a plurality of first electrode tabs (311) and a plurality of first electrode tabs (331) may be pre-welded and then welded to the first collector plate (510) to be joined. However, in this case, compared to the present embodiment, the gap between the upper surfaces of the first electrode assembly (310) and the second electrode assembly (330) and the first collector plate (510) is greatly increased. Accordingly, the size of the secondary battery (10) increases, and the size of the battery module and battery pack including the plurality of secondary batteries may also increase. The energy density per unit volume of the secondary battery also decreases.

[0118]

[0119] Below, a secondary battery according to a second embodiment of the present invention is described.

[0120] FIG. 14 is a drawing showing a state in which an electrode assembly and a first collector plate of a secondary battery according to a second embodiment of the present invention are combined, and FIG. 15 is a drawing showing the electrode assembly of FIG. 14 cut in the width direction. FIG. 16 is a modified example of the first collector plate of FIG. 14, and FIG. 17 is a drawing showing the electrode assembly of FIG. 16 cut in the width direction.

[0121] Referring to FIGS. 14 and 15, the secondary battery according to the second embodiment of the present invention has the same structure as the secondary battery according to the first embodiment described above except for the third electrode assembly (350), and therefore, a duplicate description of the same configuration will be omitted.

[0122] According to the present embodiment, a first electrode assembly (310), a second electrode assembly (330), and a third electrode assembly (350) may be sequentially arranged in parallel inside the case (100). As described above, a plurality of first electrode tabs (311) of adjacent first electrode assemblies (310) and a plurality of first electrode tabs (331) of adjacent second electrode assemblies (330) may be arranged to be inclined in opposite directions, i.e., in directions facing each other.

[0123] Additionally, the plurality of first electrode tabs (331) of the adjacent second electrode assembly (330) and the plurality of first electrode tabs (351) of the third electrode assembly (350) may be arranged to be inclined in opposite directions. However, the plurality of first electrode tabs (331) and the plurality of first electrode tabs (351) may be arranged to be inclined in directions away from each other.

[0124] In this embodiment, similarly to the first embodiment, the first electrode tab (311), the first electrode tab (331), and the first electrode tab (351) can be arranged in a row. That is, the first electrode tab (311), the first electrode tab (331), and the first electrode tab (351) can be arranged in a row along the width direction of the electrode assembly (300).

[0125] At least some of the plurality of first electrode tabs (351) move upward along the edge of the first collector plate (510) and contact the upper surface of the first collector plate (510). The first electrode tabs (351) and the first electrode tabs (331) located on the upper surface of the first collector plate (510) are arranged to be inclined toward each other.

[0126] In addition, with respect to the first collector plate (510), the first electrode tab (351) located on the upper side of the first collector plate (510) and the first electrode tab (351) located on the lower side of the first collector plate (510) are arranged to be inclined in opposite directions.

[0127] Meanwhile, as shown in FIGS. 16 and 17, at the bottom of the first collector plate (510), the first electrode tab (351) and the first electrode tab (331) can be arranged to be inclined in the same direction.

[0128] At least some of the first electrode tabs (351) are inserted into the first cutout (540) of the first collector plate (510), and the inserted first electrode tabs (351) come into contact with the upper surface of the first collector plate (510). With respect to the first collector plate (510), the first electrode tabs (351) located on the upper side of the first collector plate (510) and the first electrode tabs (351) located on the lower side of the first collector plate (510) are arranged to be inclined in opposite directions.

[0129]

[0130] Below, a secondary battery according to a third embodiment of the present invention is described.

[0131] FIG. 18 is a drawing showing a state in which an electrode assembly and a first collector plate of a secondary battery according to a third embodiment of the present invention are combined, and FIG. 19 is a drawing looking from above at FIG. 18.

[0132] Referring to FIGS. 18 and 19, the secondary battery according to the second embodiment of the present invention has the same structure as the secondary battery according to the first embodiment except for the first electrode tab (311, 331), and therefore, a duplicate description of the same configuration will be omitted. In the present embodiment, the second electrode tab (315, 335) also has the same structure as the first electrode tab (311, 331), and therefore, a description of the structure of the second electrode tab (315, 335) will be omitted.

[0133] According to the present embodiment, the first electrode tab (311) of the first electrode assembly (310) and the first electrode tab (331) of the second electrode assembly (330) may be arranged in different columns. That is, the first electrode tab (311) and the second electrode tab (331) may be arranged in different columns with respect to the width direction of the electrode assembly (300).

[0134] In addition, the first electrode tabs (311, 331) inserted into the first cutout (540) of the first collector plate (510) are positioned on different electrode assemblies (310, 330). More specifically, the first electrode tab (311) of the first electrode assembly (310) that penetrates the first cutout (540) comes into contact with the upper surface of the first collector plate (510) on the second electrode assembly (330). Unlike the embodiment described above, the first electrode tab (311) that penetrates the first cutout (540) is not positioned on the upper surface of the first collector plate (510) on the first electrode assembly (310), but is positioned on the upper surface of the first collector plate (510) on the second electrode assembly (330).

[0135] Similarly, the first electrode tab (331) of the second electrode assembly (330) that penetrates the first cut (540) is in contact with the upper surface of the first collector plate (510) above the first electrode assembly (310).

[0136] According to the present embodiment, the angle at which the first electrode tab (311, 331) penetrating the first cut portion (540) is bent or folded is smaller than that of the first embodiment. While in the first embodiment, the first electrode tab (311, 331) is bent or folded at an angle of 90 degrees or more and approximately 180 degrees, in the present embodiment, the first electrode tab (311, 331) is bent or folded at an angle smaller than that, thereby preventing the first electrode tab (311, 331) from being damaged or cut.

[0137]

[0138] Below, a secondary battery according to a fourth embodiment of the present invention is described.

[0139] FIG. 20 is a drawing showing a state in which an electrode assembly and a first collector plate of a secondary battery according to a fourth embodiment of the present invention are combined, and FIGS. 21 and 22 are modified examples of the secondary battery shown in FIG. 20.

[0140] Referring to FIG. 20, the secondary battery according to the fourth embodiment of the present invention has the same structure as the secondary battery according to the third embodiment described above, except for the third electrode assembly (350), and therefore, a duplicate description of the same configuration will be omitted.

[0141] According to the present embodiment, a first electrode assembly (310), a second electrode assembly (330), and a third electrode assembly (350) may be sequentially arranged in parallel inside the case (100). As described above, a plurality of first electrode tabs (311) of adjacent first electrode assemblies (310) and a plurality of first electrode tabs (331) of adjacent second electrode assemblies (330) may be arranged to be inclined in opposite directions, i.e., in directions facing each other.

[0142] Additionally, the plurality of first electrode tabs (331) of the adjacent second electrode assembly (330) and the plurality of first electrode tabs (351) of the third electrode assembly (350) may be arranged to be inclined in the same direction.

[0143] At least a portion of the first electrode tab (351) of the third electrode assembly (350) penetrates the first cutout (540) and contacts the upper surface of the first collector plate (510) above the adjacent second electrode assembly (330).

[0144] Meanwhile, in the modified example of FIG. 21, the first electrode tab (351) of the third electrode assembly (350) is inclined in the same direction as the first electrode tab (331) of the second electrode assembly (330), and at least a portion of the first electrode tab (351) penetrates the first cut portion (540) and contacts the upper surface of the first collector plate (510). Here, the first electrode tab (351) penetrating the first cut portion (540) is located on the upper surface of the first collector plate (510) above the third electrode assembly (350).

[0145] Additionally, in the modified example of FIG. 22, the first electrode tab (351) of the third electrode assembly (350) is tilted in the opposite direction to the first electrode tab (331) of the second electrode assembly (330), and at least a portion of the first electrode tab (351) moves upward along the edge of the first collector plate (510) to contact the upper surface of the first collector plate (510).

[0146]

[0147] Below, a secondary battery according to a fifth embodiment of the present invention is described.

[0148] FIG. 23 is a drawing illustrating a first electrode tab of an electrode assembly of a secondary battery according to a fifth embodiment of the present invention.

[0149] Referring to FIG. 23, the secondary battery according to the fifth embodiment of the present invention has the same structure as the secondary battery according to the first embodiment described above except for the first electrode tab (311, 331), and therefore, a duplicate description of the same configuration will be omitted. In the present embodiment, the structure of the second electrode tab (315, 335) is the same as that of the first electrode tab (311, 331), and therefore, a description of the structure of the second electrode tab (315, 335) will be omitted.

[0150] According to the present embodiment, the plurality of first electrode tabs (311) may have different lengths. More specifically, the length of the first electrode tab (311b) adjacent to the first electrode tab (331) among the plurality of first electrode tabs (311) is greater than the length of the first electrode tab (311a) that is somewhat spaced apart from the first electrode tab (331). The proportion of the first electrode tab (311b) having a large length among the entire first electrode tabs (311) may be approximately 20% or less. That is, some of the first electrode tabs (311b) adjacent to the first electrode tab (331) are greater in length than the remaining some of the first electrode tabs (311a). At this time, the first electrode tab (311b) may be inserted into the first cutout (540).

[0151] Likewise, the plurality of first electrode tabs (331) may have different lengths. More specifically, the length of the first electrode tab (331b) adjacent to the first electrode tab (311) among the plurality of first electrode tabs (331) is greater than the length of the first electrode tab (331a) that is somewhat spaced apart from the first electrode tab (311). The proportion of the first electrode tabs (331b) having a large length among the entire first electrode tabs (331) may be approximately 20% or less. That is, some of the first electrode tabs (331b) adjacent to the first electrode tab (311) are greater in length than the remaining some of the first electrode tabs (331a). At this time, the first electrode tab (331b) may be inserted into the first cutout (540).

[0152] In the present embodiment, when the lengths of the first electrode tabs (311b) and the first electrode tabs (331b) that are adjacent to each other are formed to be greater than the lengths of the first electrode tabs (311a) and the first electrode tabs (331a), the first electrode tabs (311b) and the first electrode tabs (331b) that penetrate the first cutout (540) of the first current collector plate (510) can be firmly coupled to the upper surface of the first current collector plate (510). Since the lengths of the first electrode tabs (311b) and the first electrode tabs (331b) are relatively long, the contact area with the upper surface of the first current collector plate (510) increases.

[0153]

[0154] Below, a secondary battery according to the sixth embodiment of the present invention is described.

[0155] Fig. 24 is a perspective view showing a first collector plate of a secondary battery according to a sixth embodiment of the present invention.

[0156] Referring to FIG. 24, the secondary battery according to the sixth embodiment of the present invention has the same structure as the secondary battery according to the first embodiment described above, except for the first collector plate (510), and therefore, a duplicate description of the same configuration will be omitted. In the present embodiment, the structure of the second collector plate (530) is the same as that of the first collector plate (510), and therefore, a description of the structure of the second collector plate (530) will be omitted.

[0157] According to the present embodiment, the first connection terminal (511) can be connected to the first collector plate (510) by welding or the like. While in the first embodiment described above, the first connection terminal (511) and the first collector plate (510) are formed integrally, the first connection terminal (511) and the first collector plate (510) can be formed by welding separate members.

[0158] The first connecting terminal (511) may be inserted into and welded to the groove (511a) of the first collector plate (510), or may be fixed by being directly welded to the upper surface of the first collector plate (510).

[0159] Above, one embodiment of the present invention has been described, but a person having ordinary skill in the art will be able to modify and change the present invention in various ways by adding, changing, deleting or adding components, etc., within the scope that does not depart from the spirit of the present invention described in the claims, and this will also be considered to be included within the scope of the rights of the present invention.

Claims

1. Case; A plurality of electrode assemblies each of which is housed in the case and includes a first electrode, a separator, and a second electrode; A first electrode tab coupled to the first electrode; A second electrode tab coupled to the second electrode; A first collector plate coupled to the first electrode tab; A second collector plate coupled to the second electrode tab; The case is sealed, and includes a cap assembly having first and second terminals respectively connected to the first collector plate and the second collector plate. A secondary battery, wherein a first cutout is formed in the first collector plate into which at least a portion of the first electrode tab is inserted.

2. In paragraph 1, A secondary battery, wherein the first electrode tab inserted into the first incision contacts the upper surface of the first current collector plate.

3. In paragraph 2, A secondary battery, wherein the first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies are in contact with the upper surface of the first current collector and are tilted in opposite directions.

4. In paragraph 1, A secondary battery, wherein the first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies are inclined in opposite directions at the lower portion of the first collector plate.

5. In paragraph 4, A secondary battery, wherein the first electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies are inclined to face each other at the lower portion of the first collector plate.

6. In paragraph 5, A secondary battery, wherein the first electrode tab of one of the pair of electrode assemblies is positioned above the first current collector plate and the first electrode tab is positioned below the first current collector plate, and the first electrode tab is inclined in opposite directions.

7. In paragraph 5, A secondary battery, wherein the first electrode tabs of each of the pair of electrode assemblies are positioned in the same row.

8. In paragraph 5, A secondary battery, wherein the first electrode tabs of each of the pair of electrode assemblies are positioned in different columns.

9. In paragraph 1, A secondary battery, wherein the first cut portion is formed by cutting a portion of a side surface of the first collector plate.

10. In paragraph 1, A secondary battery, wherein the first cut portion has a cross-section that is perpendicular to the upper surface of the first collector plate.

11. In paragraph 1, A secondary battery, wherein the first cut portion has an inclined cross-section.

12. In paragraph 1, A secondary battery, wherein the first incision has an arc-shaped cross-section.

13. In paragraph 1, A secondary battery, wherein the facing sides of the pair of electrode assemblies are positioned below the first cut portion.

14. In paragraph 1, A secondary battery, wherein the remaining end of the first electrode tab is in line contact with the lower surface of the first current collector plate.

15. In paragraph 14, A secondary battery, wherein the first electrode tab is joined to the first collector plate by welding.

16. In paragraph 1, The above first electrode tabs are of equal length, a secondary battery.

17. In paragraph 1, A secondary battery, wherein a second cutout is formed in the second collector plate into which at least a portion of the second electrode tab is inserted.

18. In paragraph 17, A secondary battery, wherein the second electrode tab inserted into the second incision contacts the upper surface of the second collector plate.

19. In paragraph 18, A secondary battery, wherein the second electrode tabs of each pair of adjacent electrode assemblies among the plurality of electrode assemblies are inclined to face each other at the lower portion of the second collector plate.

20. In paragraph 1, A secondary battery wherein the electrode assembly is of a stacked or wound type.

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