Secondary battery

Abstract

The present invention relates to a secondary battery that reduces the overall resistance of the secondary battery, improves space utilization, and allows for easy injection of an electrolyte. A secondary battery according to an embodiment of the present invention comprises a case, an electrode assembly, and a cap assembly. An opening is formed in the case. The electrode assembly is inserted into the case through the opening and is provided with an electrode portion and a plurality of foil tabs formed on the electrode portion. The cap assembly seals the opening of the case into which the electrode assembly is inserted. The cap assembly includes a cap plate, an upper gasket, an insulating plate, an electrode terminal, and a current collector. A through hole is formed in the cap plate. The insulating plate is positioned below the cap plate, and the upper gasket is positioned above the cap plate. An electrode terminal is positioned above the upper gasket, and an insertion hole is formed therein. The current collector comprises a current collector plate and a current collector projection formed on the upper surface of the current collector plate, inserted into the insertion hole, and welded to the upper end of the electrode terminal.

Description

Technology Field

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

[0002] Secondary batteries, which possess electrical characteristics such as high energy density and high applicability across product categories, are widely applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) driven by electric power sources.

[0003] These secondary batteries are attracting attention as a new energy source for improving eco-friendliness and energy efficiency, as they not only have the primary advantage of being able to drastically reduce the use of fossil fuels but also the advantage of not generating any by-products from the use of energy.

[0004] Currently, widely used types of secondary batteries include lithium-ion batteries, lithium-polymer batteries, nickel-cadmium batteries, nickel-hydrogen batteries, and nickel-zinc batteries. The operating voltage of these unit secondary battery cells is approximately 2.5V to 4.5V.

[0005] Secondary batteries can be classified according to the shape of the battery case into can-type secondary batteries, in which the electrode assembly is embedded in a metal can, and pouch-type secondary batteries, in which the electrode assembly is embedded in a pouch of aluminum laminate sheet. Can-type secondary batteries can be classified into cylindrical secondary batteries and prismatic secondary batteries depending on the shape of the metal can.

[0006] In a prismatic secondary battery, an electrode assembly is housed within a metal case, and a cap member is attached to the open end.

[0007] Conventional cap members use rivets to connect the electrode terminals and the cap plate, which increases the number of parts and consequently raises the overall resistance of the secondary battery, while the rivets cause a problem of reduced space utilization.

[0008] In addition, prismatic batteries are equipped with an electrolyte injection port; however, if the electrolyte injection port is blocked by foreign substances or internal components, problems such as reduced electrolyte injection speed or backflow of electrolyte may occur. The problem to be solved

[0009] The present invention aims to provide a secondary battery that reduces the overall resistance of the secondary battery, improves space utilization, and allows for easy injection of the electrolyte. means of solving the problem

[0010] A secondary battery according to an embodiment of the present invention comprises a case, an electrode assembly, and a cap assembly. An opening is formed in the case. The electrode assembly is inserted into the case through the opening and is provided with an electrode portion and a plurality of foil tabs formed on the electrode portion. The cap assembly seals the opening of the case into which the electrode assembly is inserted. The cap assembly includes a cap plate, an upper gasket, an insulating plate, an electrode terminal, and a current collector. A through hole is formed in the cap plate. The insulating plate is positioned below the cap plate, and the upper gasket is positioned above the cap plate. An electrode terminal is positioned above the upper gasket, and an insertion hole is formed therein. The current collector comprises a current collector plate and a current collector projection formed on the upper surface of the current collector plate, inserted into the insertion hole, and welded to the upper end of the electrode terminal.

[0011] A secondary battery according to an embodiment of the present invention includes a sealing gasket interposed between a through hole and a current collecting projection, and a current collecting plate may be arranged to be in contact with the sealing gasket and the lower surface of an insulating plate.

[0012] In a secondary battery according to an embodiment of the present invention, the current collecting protrusion includes a first current collecting protrusion and a second current collecting protrusion. The first current collecting protrusion is formed on the upper surface of a current collecting plate and may be formed with a first diameter. The second current collecting protrusion is formed on the upper surface of the first current collecting protrusion and may be formed with a second diameter smaller than the first diameter.

[0013] In a secondary battery according to an embodiment of the present invention, the step created by the first current collecting protrusion and the second current collecting protrusion can engage with the step created by the sealing gasket and the lower surface of the electrode terminal.

[0014] In a secondary battery according to an embodiment of the present invention, a groove may be formed on the upper surface of the second current collector projection. The groove may be formed in a truncated cone shape or a hemispherical shape.

[0015] In a secondary battery according to an embodiment of the present invention, the cap plate has a seating surface formed around a through hole and a stepped surface protruding from the outside of the seating surface, and an upper gasket may be interposed between the cap plate and the electrode terminal.

[0016] In a secondary battery according to an embodiment of the present invention, the upper gasket may include a first horizontal surface formed with a first thickness and formed to be in contact with the seating surface of a cap plate, a second horizontal surface formed with a second thickness thicker than the first thickness and formed to be in contact with the seating surface and the stepped surface, and a vertical surface extending in a vertical direction from the outer end of the second horizontal surface and wrapping around the outer surface of an electrode terminal.

[0017] In a secondary battery according to an embodiment of the present invention, a first alignment projection is formed on the lower surface of the through-hole side of the cap plate in a shape connected to the through-hole, and a first alignment groove may be formed in the sealing gasket at a position corresponding to the first alignment projection.

[0018] In a secondary battery according to an embodiment of the present invention, a second alignment projection is formed on the upper surface of the current collector plate, and a second alignment groove may be formed on the lower surface of the sealing gasket at a position corresponding to the second alignment projection.

[0019] In a secondary battery according to an embodiment of the present invention, a fitting groove is formed on the lower surface of an electrode terminal, and a fitting projection that fits into the fitting groove may be formed on the upper surface of a first current collecting projection. The fitting groove is formed in a stepped portion created by the first current collecting projection and the second current collecting projection, and The fitting projection can be formed at a position corresponding to the fitting groove on the upper surface of the first collector projection located on the outer side of the second collector projection.

[0020] In a secondary battery according to an embodiment of the present invention, a first undercut is formed at the bottom of the sealing gasket, and a first inclined surface having a shape corresponding to the first undercut may be formed at the bottom of the first current collector projection.

[0021] In a secondary battery according to an embodiment of the present invention, a second undercut is formed on the lower surface of the insertion hole side of the electrode terminal, and a second inclined surface having a shape corresponding to the second undercut may be formed on the lower surface of the second current collecting projection.

[0022] In a secondary battery according to an embodiment of the present invention, a current collecting protrusion is formed at the center of the upper surface of the current collecting plate, and an adhesive layer including a heat-fusion layer may be formed on both sides of the upper surface of the current collecting plate.

[0023] A secondary battery according to an embodiment of the present invention may include an insulating member disposed between a cap plate and an electrode assembly and having an insulating plate. The insulating member may include a guide hole located below an electrolyte injection port formed in the cap plate and a guide portion protruding downward from the guide hole to guide the movement of the electrolyte.

[0024] In a secondary battery according to an embodiment of the present invention, the guide portion may include a support located at the lower part of the guide hole that partially blocks the guide hole, and an internal hole formed in the support to move fluid.

[0025] In a secondary battery according to an embodiment of the present invention, the guide portion may include a guide rim and a support. The guide rim surrounds the lower part of the guide hole, the support is fixed to the guide rim, and a first opening and a second opening may be formed between the side end of the support and the inner wall of the guide rim.

[0026] In a secondary battery according to an embodiment of the present invention, a vent portion for discharging gas may be formed in the cap plate. At this time, the insulating member includes an exhaust portion that protrudes toward the bottom of the case and has a plurality of discharge openings, and the exhaust portion may be located below the vent portion.

[0027] In a secondary battery according to an embodiment of the present invention, a plurality of foil tabs can be formed in one direction of the electrode assembly.

[0028] In a secondary battery according to an embodiment of the present invention, a plurality of foil tabs can be formed in both directions of the electrode assembly.

[0029] In a secondary battery according to an embodiment of the present invention, after the electrode assembly and the current collector plate are combined, a first insulating tape may be attached to the current collector plate. Then, after the outer surface of the electrode assembly is wrapped with a second insulating tape, the electrode assembly may be inserted into a case. Then, the outer surface of the case into which the electrode assembly is inserted may be wrapped with a third insulating tape. Effects of the invention

[0030] According to the present invention, the number of parts is reduced to decrease the overall resistance of the secondary battery and improve space utilization, and the sealing function is strengthened to prevent leakage of the electrolyte. In addition, a guide portion for injecting the electrolyte is formed in the electrolyte injection port so that the electrolyte can be easily injected. Brief explanation of the drawing

[0031] FIG. 1 is a perspective view showing a secondary battery according to one embodiment of the present invention. Figure 2 is a cross-sectional view taken along line AA in Figure 1. FIG. 3 is an exploded perspective view of a secondary battery according to one embodiment of the present invention. FIG. 4 is a perspective view showing an electrode assembly having a plurality of first and second foil tabs formed on an electrode portion in a secondary battery according to one embodiment of the present invention. FIG. 5 is a drawing showing a first electrode plate and a second electrode plate in a secondary battery according to one embodiment of the present invention. FIG. 6 is an exploded perspective view of a secondary battery according to another embodiment of the present invention. FIG. 7 is a perspective view showing an electrode assembly having a plurality of first and second foil tabs formed on an electrode portion in a secondary battery according to another embodiment of the present invention. FIGS. 8 and 9 are drawings showing a first electrode plate and a second electrode plate in a secondary battery according to an embodiment of the present invention. FIG. 10 is a perspective view showing a cap assembly according to a first embodiment of the present invention. FIG. 11 is a cross-sectional view showing a cap assembly according to a first embodiment of the present invention. FIG. 12 is a cross-sectional view showing a cap assembly according to a second embodiment of the present invention. FIG. 13 is a cross-sectional view showing a cap assembly according to a third embodiment of the present invention. FIG. 14 is a cross-sectional view showing a cap assembly according to a fourth embodiment of the present invention. FIG. 15 is a top perspective view of an insulating member of a secondary battery according to embodiments of the present invention. FIG. 16 is a perspective view from below of an insulating member of a secondary battery according to embodiments of the present invention. FIG. 17 is a bottom view of an insulating member of a secondary battery according to embodiments of the present invention. FIG. 18 is a partial cross-sectional view illustrating a cap plate and an insulating member. FIG. 19 is a cutaway perspective view illustrating one embodiment of a guide portion of an insulating member. FIG. 20 is a cross-sectional view illustrating another embodiment of the guide portion of the insulating member. FIG. 21 is a cross-sectional view illustrating the exhaust portion of an insulating member. FIG. 22 is a drawing illustrating the process of combining a foil tab and a current collector in a secondary battery according to one embodiment of the present invention. FIG. 23 is a drawing illustrating the process of combining a cap member and a current collector member in a secondary battery according to one embodiment of the present invention. FIG. 24 is a drawing illustrating the process of combining a current collector and a foil tab when the foil tab is formed in both directions in a secondary battery according to one embodiment of the present invention. FIG. 25 is a drawing illustrating the process of combining a cap member with a current collector member. FIG. 26 is a drawing illustrating the process of combining a foil tab and a current collector in a secondary battery according to another embodiment of the present invention. FIG. 27 is a drawing illustrating the process of combining a cap member and a current collector member in a secondary battery according to another embodiment of the present invention. FIG. 28 is a drawing illustrating the process of combining a current collector and a foil tab when the foil tab is formed in both directions in a secondary battery according to another embodiment of the present invention. FIG. 29 is a drawing illustrating the process of combining a cap member with a current collector member. FIG. 30 is a drawing illustrating the process of attaching an insulating tape while the electrode assembly and the current collector are combined. FIG. 31 is a drawing showing a secondary battery including two electrode portions according to another embodiment of the present invention. FIG. 32 is a drawing showing a foil tab formed on two electrode portions according to another embodiment of the present invention joined to a current collector member. Specific details for implementing the invention

[0032] The present invention is capable of various modifications and may have various embodiments, and 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, and it should be understood that it includes all modifications, equivalents, and substitutions that fall within the spirit and scope of the invention.

[0033] The terms used in this invention are used merely to describe specific embodiments and are not intended to limit the invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this invention, terms such as "comprising" or "having" are intended to indicate the existence of the features, numbers, steps, actions, components, parts, or combinations thereof described in the specification, and should be understood as not precluding the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0034] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Note that in the accompanying drawings, identical components are indicated by the same reference numerals whenever possible. Furthermore, detailed descriptions of known functions and configurations that may obscure the essence of the present invention will be omitted. For the same reason, some components in the accompanying drawings may be exaggerated, omitted, or schematically depicted.

[0036] FIG. 1 is a perspective view showing a secondary battery according to one embodiment of the present invention, FIG. 2 is a cross-sectional view taken along line AA in FIG. 1, FIG. 3 is an exploded perspective view showing a secondary battery according to one embodiment of the present invention, FIG. 4 is a perspective view showing an electrode assembly having a plurality of first and second foil tabs formed on an electrode portion in a secondary battery according to one embodiment of the present invention, and FIG. 5 is a drawing showing a first electrode plate and a second electrode plate in a secondary battery according to one embodiment of the present invention.

[0037] As illustrated in FIGS. 1 to 5, a secondary battery (1000) according to one embodiment of the present invention includes a case (1100), an electrode assembly (1200), a current collector (1300), a cap member (1400), and an insulating member (1500).

[0038] The case (1100) forms the exterior of the secondary battery (1000). The case (1100) has a space formed inside to accommodate an electrode assembly (1200) and may have an opening formed on one side. In this embodiment, the case (1100) has a rectangular shape, but is not limited thereto and can be modified in various ways. The material of the case (1100) may be made of a rigid material capable of protecting the electrode assembly (1200) accommodated inside. For example, the case (1100) may be made of a metal such as aluminum or stainless steel.

[0039] An electrolyte may be contained within the case (1100) along with an electrode assembly (1200). The electrolyte may consist 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 in a liquid, solid, or gel form.

[0040] The electrode assembly (1200) is housed inside the case (1100). As illustrated in FIG. 4, the electrode assembly (1200) comprises an electrode portion (1210), a plurality of first foil tabs (1220), and a plurality of second foil tabs (1230). The plurality of first and second foil tabs (1220, 1230) are disposed at one end of the electrode portion (1210). In another embodiment, the first foil tab (1220) may be disposed on one side of the electrode portion (1210), and the second foil tab (1230) may be disposed on the other side of the electrode portion (1210). The plurality of first foil tabs (1220) are aligned with each other, and the plurality of second foil tabs (1230) are aligned with each other.

[0041] The electrode portion (1210) is provided with a plurality of first electrode plates (1211), a plurality of second electrode plates (1212), and a separator (1213).

[0042] An active material may be applied to a plurality of first electrode plates (1211) and a plurality of second electrode plates (1212). An active material, such as a transition metal oxide, may be applied to a metal plate such as aluminum on a plurality of first electrode plates (1211). A plurality of first electrode plates (1211) may be positive electrode plates. An active material, such as graphite or carbon, may be applied to a metal plate such as copper or nickel on a plurality of second electrode plates (1212). A plurality of second electrode plates (1212) may be negative electrode plates.

[0043] The separator (1213) is positioned between a plurality of first and second electrode plates (1211, 1212) to prevent short circuits between the plurality of first and second electrode plates (1211, 1212). The material of the separator may be polyethylene, polypropylene, or a composite thereof.

[0044] The electrode portion (1210) can be formed by positioning a separator (1213) between a first electrode plate (1211) and a second electrode plate (1212) that are arranged sequentially. That is, in one embodiment, the electrode portion (1210) can be formed by stacking the first electrode plate (1211), the separator (1213), the second electrode plate (1212), and the separator (1213) in the order of tens to hundreds of times.

[0045] In this embodiment, the electrode assembly (1200) has one electrode part (1210), but in other embodiments, the electrode assembly (1200) may have a plurality of electrode parts (1210). The plurality of electrode parts (1210) may be electrically connected to each other.

[0046] A foil tab (1220, 1230) on which no active material is applied is formed at one end of a plurality of first and second electrode plates (1211, 1212). In one embodiment, the electrode plates (1211, 1212) and the foil tabs (1220, 1230) may be formed integrally by cutting a predetermined portion of a metal plate using a laser or the like to leave the electrode plates (1211, 1212) and the foil tabs (1220, 1230). The plurality of foil tabs (1220, 1230) may be formed in a direction toward the cap member (1400).

[0047] When a plurality of first and second electrode plates (1211, 1212) are stacked, a plurality of first foil tabs (1220) overlap each other at a first position. A plurality of second foil tabs (1230) overlap each other at a second position. That is, a plurality of first foil tabs (1220) having the same polarity are grouped at a first position, and a plurality of second foil tabs (1230) are grouped at a second position. The first position and the second position are separated from each other on the electrode plates, and the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) grouped respectively can be spaced apart in the longitudinal direction of the electrode assembly (1200).

[0048] Multiple foil tabs (1220, 1230) overlapped at each location can be connected to a current collector member, such as by ultrasonic welding or laser welding, to facilitate the movement of current.

[0049] The current collecting member (1300) is equipped with a current collecting plate (1310) and a current collecting projection (1320).

[0050] A plurality of foil tabs (1220, 1230) are bent and welded to the collector plate (1310). A collector projection (1320) is formed in the center of the collector plate (1310).

[0051] The current collection projection (1320) protrudes upward from the upper surface of the current collection plate (1310) and is coupled to the terminal hole (1421) of the electrode terminal (1420) to electrically connect the electrode assembly (1200) and the electrode terminal (1420).

[0052] The current collector (1300) may be made of the same material as the plurality of foil tabs (1220, 1230). An insulating material may be placed on the lower part of the current collector (1300). The insulating material may be an insulating film.

[0053] After welding a plurality of first foil tabs (1220) together and a plurality of second foil tabs (1230) together, a current collecting member (1300) is placed on each of the first foil tabs (1220) and the second foil tabs (1230).

[0054] After bending a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230), a current collecting member (1300) is welded on the plurality of first foil tabs (1220) and a plurality of second foil tabs (1230). The welding may be performed using methods such as ultrasonic welding or laser welding.

[0055] The cap member (1400) may include a cap plate (1410), an electrode terminal (1420), an electrolyte injection port (1430), and a vent portion (1440).

[0056] The cap plate (1410) is in the shape of a plate that covers the opening of the case (1100) and has at least one through hole (1410a). The cap plate (1410) may have a shape corresponding to the shape of the opening of the case (1100). The cap plate (1410) may be formed of the same material as the case (1100), and the cap plate (1410) may be fixed to the case (1100) by a method such as laser welding.

[0057] An electrolyte injection port (1430) and a vent portion (1440) may be formed in the cap plate (1410).

[0058] Electrolyte can be injected into the interior of the case (1100) through the electrolyte injection port (1430). The vent (1440) opens when the internal pressure of the case (1100) exceeds a reference value.

[0059] The electrode terminal (1420) can be coupled to the cap plate (1410) via the current collector (1300). The electrode terminal (1420) is electrically connected to the foil tabs (1220, 1230) through the current collector (1300). The electrode terminal (1420) can be in the shape of a circular or square plate.

[0060] The insulating member (1500) is installed between the cap member (1400) and the electrode assembly (1200) to insulate the cap member (1400) and the electrode assembly (1200).

[0062] FIG. 6 is an exploded perspective view of a secondary battery according to another embodiment of the present invention, FIG. 7 is a perspective view of an electrode assembly having a plurality of first and second foil tabs formed on an electrode portion in a secondary battery according to another embodiment of the present invention, and FIG. 8 and FIG. 9 are drawings showing a first electrode plate and a second electrode plate in a secondary battery according to one embodiment of the present invention.

[0063] As illustrated in FIGS. 6 to 9, a secondary battery (1000a) according to another embodiment of the present invention comprises a case (1100), an electrode assembly (1200a), a current collector (1300a), a cap member (1400), and an insulating member (1500). Since the structure of the electrode assembly (1200a) and the current collector (1300a) is different from that of the secondary battery of the aforementioned embodiment, and the remaining components are substantially the same, a repeated description is omitted.

[0064] As illustrated in FIG. 7, the electrode assembly (1200a) comprises an electrode portion (1210a), a plurality of first_1 foil tabs (1220a), a plurality of first_2 foil tabs (1220b), a plurality of second_1 foil tabs (1230a), and a plurality of second_2 foil tabs (1230b). The plurality of foil tabs (1220a to 1230b) are disposed at one end of the electrode portion (1210a). A plurality of first_1 foil tabs (1220a) are aligned with each other, a plurality of first_2 foil tabs (1220b) are aligned with each other, a plurality of second_1 foil tabs (1230a) are aligned with each other, and a plurality of second_2 foil tabs (1230b) are aligned with each other. Each of the aligned foil tabs (1220a to 1230b) is arranged so as not to overlap in the width and length directions of the electrode assembly (1200a).

[0065] As illustrated in FIGS. 8 and 9, the electrode portion (1210a) comprises a plurality of first electrode plates (1211a), a plurality of first electrode plates (1211b), a plurality of second electrode plates (1212a), a plurality of second electrode plates (1212b), and a separator (1213).

[0066] An active material may be applied to a plurality of first-1 electrode plates (1211a), a plurality of first-2 electrode plates (1211b), a plurality of second-1 electrode plates (1212a), and a plurality of second-2 electrode plates (1212b). An active material, such as a transition metal oxide, may be applied to a metal plate such as aluminum for the plurality of first-1 electrode plates (1211a) and the plurality of first-2 electrode plates (1211b). The plurality of first-1 electrode plates (1211a) and the plurality of first-2 electrode plates (1211b) may have the same polarity and may be positive plates. An active material, such as graphite or carbon, may be applied to a metal plate such as copper or nickel for the plurality of second-1 electrode plates (1212a) and the plurality of second-2 electrode plates (1212b). A plurality of 2_1 electrode plates (1212a) and a plurality of 2_2 electrode plates (1212b) may have the same polarity and may be negative plates.

[0067] The separator (1213) is positioned between the plurality of electrode plates (1211a to 1212b) to prevent short circuits between the plurality of electrode plates (1211a to 1212b).

[0068] The electrode portion (1210a) can be formed by positioning a separator (1213) between the first electrode plate (1211a) and the second electrode plate (1212a) and the first electrode plate (1211b) and the second electrode plate (1212b) that are arranged sequentially.

[0069] The electrode assembly (1200a) has one electrode portion (1210a), but in another embodiment, the electrode assembly (1200a) may have a plurality of electrode portions (1210a). The plurality of electrode portions (1210a) may be electrically connected to each other.

[0070] A foil tab (1220a, 1220b, 1230a, 1230b) without active material applied is formed at one end of a plurality of electrode plates (1211a to 1212b). In one embodiment, the electrode plates (1211a to 1212b) and the foil tab (1220a, 1220b, 1230a, 1230b) may be formed integrally by cutting a predetermined portion of a metal plate using a laser or the like to leave the electrode plates (1211a to 1212b) and the foil tab (1220a, 1220b, 1230a, 1230b). The plurality of foil tabs (1220a, 1220b, 1230a, 1230b) may be formed in a direction toward the cap member (1400).

[0071] A first_1 foil tab (1220a) is formed at a first position of the first_1 electrode plate (1211a). A first_2 foil tab (1220b) is formed at a second position of the first_2 electrode plate (1211b). Similarly, a second_1 foil tab (1230a) is formed at a third position of the second_1 electrode plate (1212a), and a second_2 foil tab (1230b) can be formed at a fourth position of the second_2 electrode plate (1212b).

[0072] A plurality of first_1 electrode plates (1211a) and a plurality of second_1 electrode plates (1212a) can be alternately stacked with a separator (1213) in between. The stack of a plurality of first_1 electrode plates (1211a) and a plurality of second_1 electrode plates (1212a) forms half of the electrode portion (1210a).

[0073] A plurality of first_2 electrode plates (1211b) and a plurality of second_2 electrode plates (1212b) may be alternately stacked with a separator (1213) in between. The stack of the plurality of first_2 electrode plates (1211b) and the plurality of second_2 electrode plates (1212b) forms the remaining half of the electrode portion (1210a).

[0074] A stack of multiple first_1 electrode plates (1211a) and multiple second_1 electrode plates (1212a) and a stack of multiple first_2 electrode plates (1211b) and multiple second_2 electrode plates (1212b) are connected in the width direction of the electrode portion (1210a). When forming the electrode assembly (1200a), after stacking multiple first_1 electrode plates (1211a) and multiple second_1 electrode plates (1212a), multiple first_2 electrode plates (1211b) and multiple second_2 electrode plates (1212b) can be stacked.

[0075] When a plurality of electrode plates (1211a to 1212b) are stacked, a plurality of first_1 foil tabs (1220a) overlap each other at a first position. A plurality of first_2 foil tabs (1220b) overlap each other at a second position. That is, among a plurality of first_1 foil tabs (1220a) and a plurality of first_2 foil tabs (1220b) having the same polarity, a plurality of first_1 foil tabs (1220a) are grouped at a first position, and a plurality of first_2 foil tabs (1220b) are grouped at a second position. The first position and the second position are separated from each other on the electrode plates, and the plurality of first_1 foil tabs (1220a) and a plurality of first_2 foil tabs (1220b) grouped respectively can be spaced apart in the width direction and length direction of the electrode assembly (1200a).

[0076] In order to stably weld a large number of foil tabs, foil tabs of the same polarity are divided into two spaced-apart groups and aligned, and each group is welded onto a current collector plate. That is, one foil tab is formed on one electrode plate, but by making the position where the foil tab is formed on each electrode plate different, two groups of foil tabs with different positions are formed on the same electrode after the electrode plates are stacked. In another embodiment, two or more foil tabs with different positions may be formed on the same electrode.

[0077] When a plurality of electrode plates (1211a to 1212b) are stacked, a plurality of 2_1 foil tabs (1230a) overlap each other at a third position, and a plurality of 2_2 foil tabs (1230b) overlap each other at a fourth position. That is, a plurality of 2_1 foil tabs (1230a) are grouped at a third position, and a plurality of 2_2 foil tabs (1230b) are grouped at a fourth position. The third position and the fourth position are separated from each other on the electrode plates, and the plurality of 2_1 foil tabs (1230a) and the plurality of 2_2 foil tabs (1230b) grouped respectively can be spaced apart in the width direction and length direction of the electrode assembly (1200a).

[0078] A plurality of 2_1 foil tabs (1230a) and a plurality of 2_2 foil tabs (1230b) are foil tabs of the same polarity.

[0079] Multiple foil tabs (1220a, 1220b, 1230a, 1230b) overlapped at each location can be connected to a current collector plate by ultrasonic welding, laser welding, etc., respectively to facilitate the movement of current.

[0080] The current collecting member (1300a) is equipped with a current collecting plate (1310a) and a current collecting projection (1320).

[0081] The current collector plate (1310a) has a first current collection area (1311), a second current collection area (1312), and a connection area (1313).

[0082] In the first current collection area (1311), a plurality of first_1 foil tabs (1220a) are bent and welded. In the second current collection area (1312), a plurality of first_2 foil tabs (1220b) are welded. A connecting area (1313) is interposed between the first current collection area (1311) and the second current collection area (1312), and a current collection projection (1320) is formed.

[0083] The first current collection area (1311) and the second current collection area (1312) are spaced apart in the longitudinal direction by a connecting area (1313). Since the first current collection area (1311) and the second current collection area (1312) are spaced apart from each other, when a plurality of first_1 foil tabs (1220a) and a plurality of first_2 foil tabs (1220b) are welded to the first current collection area (1311) and the second current collection area (1312), respectively, they do not interfere with each other.

[0084] The current collector projection (1320) protrudes upward from the upper surface of the connection area (1313) and is coupled to the terminal hole (1421) of the electrode terminal (1420) to electrically connect the electrode assembly (1200a) and the electrode terminal (1420).

[0085] After welding multiple 1_1 foil tabs (1220a) together and multiple 1_2 foil tabs (1220b) together, a current collector plate (1310a) may be placed in the space between the 1_1 foil tabs (1220a) and the 1_2 foil tabs (1220b). At this time, the current collector plate (1310a) is placed on some of the 1_1 foil tabs (1220a) and 1_2 foil tabs (1220b).

[0086] After a current collector plate (1310a) is placed on the upper part of the electrode portion (1210a), a plurality of first_1 foil tabs (1220a) are bent toward the first current collection area (1311), and a plurality of first_2 foil tabs (1220b) are bent toward the second current collection area (1312). That is, the plurality of first_1 foil tabs (1220a) and the plurality of first_2 foil tabs (1220b) are bent in opposite directions.

[0087] After bending a plurality of first_1 foil tabs (1220a) and a plurality of first_2 foil tabs (1220b), welding is performed on the plurality of first_1 foil tabs (1220a) and a plurality of first_2 foil tabs (1220b). The welding may be performed using methods such as ultrasonic welding or laser welding.

[0088] When welding, welding can proceed from a plurality of first_1 foil tabs (1220a) toward the first current collection area (1311) of the current collection plate (1310a), and from a plurality of first_2 foil tabs (1220b) toward the second current collection area (1312) of the current collection plate. To facilitate fixing and welding of the foil tabs, a plurality of fine grooves or fine protrusions may be formed on the upper surface of the current collection plate (1310a).

[0089] In a secondary battery according to embodiments of the present invention illustrated in FIGS. 1 to 9, a current collector (1300), a cap member (1400), and an insulating member (1500) are combined to form a cap assembly (see reference numeral CA in FIG. 2).

[0091] FIG. 10 is a perspective view showing a cap assembly according to a first embodiment of the present invention, and FIG. 11 is a cross-sectional view showing a cap assembly according to a first embodiment of the present invention.

[0092] As illustrated in FIGS. 10 and 11, a cap assembly (CA1) according to a first embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), an insulating plate (1510), a sealing gasket (1450), an upper gasket (1460), and a current collector (1300).

[0093] The cap plate (1410) is in the shape of a plate covering the opening of the case (1100) and has at least one through hole (1410a). The cap plate (1410) may have a shape corresponding to the shape of the opening of the case (1100), and the cap plate (1410) may be formed of the same material as the case (1100).

[0094] Additionally, the cap plate (1410) is provided with a seating surface (1411) and a stepped surface (1412). The seating surface (1411) is formed around the through hole (1410a), and the stepped surface (1412) is formed to protrude to a predetermined height from the outside of the seating surface (1411). The first horizontal surface (1461) and the second horizontal surface (1462) of the upper gasket (1460) are arranged on the seating surface (1411), and the vertical surface (1463) of the upper gasket (1460) is arranged on the stepped surface (1412).

[0095] And, on the lower surface of the through hole (1410a) of the cap plate (1410), a first alignment projection (1413) is formed in a shape connected to the through hole (1410a). The first alignment projection (1413) is fitted into a first alignment groove (1451) formed in the sealing gasket (1450) to assist in the alignment of the cap plate (1410) and the sealing gasket (1450).

[0096] The electrode terminal (1420) can be coupled to the cap plate (1410) via the current collector (1300). The electrode terminal (1420) is electrically connected to the foil tab through the current collector (1300). The electrode terminal (1420) can be in the shape of a circular or square plate.

[0097] An insertion hole (1420a) is formed in the center of the electrode terminal (1420), and a current collecting projection (1320: 1321, 1322) is inserted into the insertion hole (1420a). The upper surface of the current collecting projection (1320) inserted into the insertion hole (1420a) and the upper surface of the electrode terminal (1420) can be welded and joined.

[0098] The electrode terminal (1420) includes a lower surface (1421) formed on the lower side, an outer stepped surface (1422) formed on the outer side of the lower surface (1421), an outer surface (1423) formed in a vertical direction at the end of the outer stepped surface (1422), and an inner stepped surface (1424) formed on the upper surface toward the insertion hole (1420a).

[0099] The lower surface (1421) is in contact with the first horizontal surface (1461) of the upper gasket (1460), the outer stepped surface (1422) is in contact with the second horizontal surface (1462), and the outer surface (1423) is wrapped by the vertical surface (1462). Additionally, the inner stepped surface (1424) is formed to be connected to the upper surface of the current collecting projection (1320), and welding is performed at the interface between the inner stepped surface (1424) and the current collecting projection (1320) so that the electrode terminal (1420) can be combined with the current collecting member (1300).

[0100] An insulating plate (1510) is positioned between the cap plate (1410) and the current collector plate (1310) to insulate the cap plate (1410) and the current collector plate (1310).

[0101] The sealing gasket (1450) is interposed between the through hole (1410a) and the current collector projection (1320) to insulate the cap plate (1410) and the current collector projection (1320), thereby preventing the electrolyte or gas inside the case (1100) from leaking out and preventing moisture or air from the outside from penetrating into the case (1100).

[0102] The upper portion of the sealing gasket (1450) extends to contact the first horizontal surface (1461) of the upper gasket (1460), and the lower portion extends horizontally while contacting the upper surface of the current collector plate (1310). Additionally, a first alignment groove (1451) is formed in the sealing gasket (1450) at a position corresponding to the first alignment projection (1413), and a second alignment groove (1452) is formed on the lower surface of the sealing gasket (1450) at a position corresponding to the second alignment projection (1314). The diameter of the sealing gasket (1450) is formed to be larger than the diameter of the insertion hole (1420a), so that the inner wall of the sealing gasket (1450) and the inner wall of the insertion hole (1420a) form a step.

[0103] The upper gasket (1460) is interposed between the cap plate (1410) and the electrode terminal (1420) to prevent the electrolyte or gas inside the case (1100) from leaking out and to prevent moisture or air from penetrating into the case (1100) from the outside.

[0104] The upper gasket (1460) includes a first horizontal surface (1461), a second horizontal surface (1462), and a vertical surface (1463). The first horizontal surface (1461) is formed with a first thickness and is formed to be in contact with the seating surface (1411) of the cap plate (1410) and the top of the sealing gasket (1450). The second horizontal surface (1462) is formed with a second thickness thicker than the first thickness and is formed to be in contact with the seating surface (1411) and the stepped surface (1412). The vertical surface (1463) extends vertically from the outer end of the second horizontal surface (1462) and covers the outer surface of the electrode terminal (1420).

[0105] The current collecting member (1300) is equipped with a current collecting plate (1310) and a current collecting projection (1320).

[0106] The current collector plate (1310) is positioned to be in contact with the lower surface of the sealing gasket (1450) and the insulating plate (1510). A second alignment projection (1314) is formed on the upper surface of the current collector plate (1310), and the second alignment projection (1314) is inserted into a second alignment groove (1452) formed on the lower surface of the sealing gasket (1450).

[0107] The collecting protrusion (1320) is formed at the center of the upper surface of the collecting plate (1310) and includes a first collecting protrusion (1321) formed with a first diameter and a second collecting protrusion (1322) formed on the upper surface of the first collecting protrusion (1321) and formed with a second diameter smaller than the first diameter.

[0108] The step created by the first current collecting projection (1321) and the second current collecting projection (1322) engages with the step created by the sealing gasket (1450) and the lower surface (1421), so that the current collecting member (1300) can be hermetically coupled with the sealing gasket (1450) and the electrode terminal (1420).

[0109] Additionally, a groove (1323) is formed on the upper surface of the second current collecting projection (1322). The groove (1323) disperses the mechanical stress applied to the current collecting projection (1320) to prevent the occurrence of fatigue cracks and absorbs micro-deformations that occur during repeated charging and discharging processes to improve durability. The groove (1323) can be formed in a truncated cone shape (V-groove) or a hemispherical shape (U-groove).

[0110] The cap assembly (CA1) according to the first embodiment of the present invention configured as described above can reduce the number of parts by welding the current collector member (1300) and the electrode terminal (1420) together in place of a rivet, thereby reducing the overall resistance of the secondary battery and improving space utilization, and can prevent leakage of the electrolyte by strengthening the sealing function.

[0112] FIG. 12 is a cross-sectional view showing a cap assembly according to a second embodiment of the present invention.

[0113] As illustrated in FIG. 12, the cap assembly (CA2) according to the second embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), an insulating plate (1510), a sealing gasket (1450), an upper gasket (1460), and a current collector (1300). Since the shape of the electrode terminal (1420) and the current collector (1300) is different, and the rest is substantially the same as the first embodiment described above, a repeated description is omitted.

[0114] In the second embodiment, a fitting groove (1421a) is formed on the side of the insertion hole (1420a) of the lower surface (1421) of the electrode terminal (1420), and a fitting projection (1321a) that fits into the fitting groove (1421a) may be formed on the upper surface of the first current collecting projection (1321).

[0115] Specifically, the fitting groove (1421a) is formed in the stepped portion created by the first collecting projection (1321) and the second collecting projection (1322), and The fitting projection (1321a) is formed at a position corresponding to the fitting groove (1421a) on the upper surface of the first collecting projection (1321) located on the outer side of the second collecting projection (1322).

[0116] When the current collecting projection (1320) is inserted into the through hole (1410a) and the insertion hole (1420a), the fitting projection (1321a) is fastened in a manner that fits into the fitting groove (1421a), thereby facilitating alignment and coupling of the electrode terminal (1420) and the current collecting member (1300), and in this fitted state, the inner stepped surface (1424) of the electrode terminal (1420) and the upper surface of the second current collecting projection (1322) are welded, thereby improving the coupling strength between the current collecting plate (1300) and the electrode terminal (1420).

[0117] At this time, the width (W) of the step portion created by the first current collecting projection (1321) and the second current collecting projection (1322) relative to the radius (R) of the first current collecting projection (1321) is preferably W : R = 1 : 2.0 to 3.0. If the width (W) is less than 1 / 3R, the supporting force of the step supporting the lower surface (1421) of the electrode terminal (1420) is weak, and if the width (W) is greater than 1 / 2R, the size of the second current collecting projection (1322) becomes smaller, which causes a problem of reduced current collection effect.

[0119] FIG. 13 is a cross-sectional view showing a cap assembly according to a third embodiment of the present invention.

[0120] As illustrated in FIG. 13, the cap assembly (CA3) according to the third embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), an insulating plate (1510), a sealing gasket (1450), an upper gasket (1460), and a current collecting member (1300). Since the shape of the electrode terminal (1420), the sealing gasket (1450), and the current collecting projection (1320) is different, and the rest is substantially the same as the first embodiment described above, a repeated description is omitted.

[0121] In this third embodiment, a first undercut (1453) having a triangular cross-section is formed at the bottom of the sealing gasket (1450), and a first inclined surface (1324) having a shape corresponding to the first undercut (1453) may be formed at the bottom of the first current collector projection (1321).

[0122] Additionally, a second undercut (1425) with a triangular cross-section is formed on the lower surface (1421) of the insertion hole (1420a) of the electrode terminal (1420), and a second inclined surface (1325) with a shape corresponding to the second undercut (1425) can be formed on the lower end of the second current collecting projection (1322).

[0123] When manufacturing a secondary battery, when inserting the current collector protrusion (1320) into the through hole (1410a) and the insertion hole (1420a), the insertion margin can be sufficiently secured due to the two-stage undercut (1453, 1425), thereby making the insertion process easier to perform.

[0124] Then, while maintaining the state where the undercut (1453, 1425) and the inclined surface (1324, 1325) are in close contact after insertion, welding can be performed on the inner stepped surface (1424) of the electrode terminal (1420) and the upper surface of the second current collecting projection (1322) to combine the electrode terminal (1420) and the current collecting member (1300).

[0126] FIG. 14 is a cross-sectional view showing a cap assembly according to a fourth embodiment of the present invention.

[0127] As illustrated in FIG. 14, the cap assembly (CA4) according to the fourth embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), an insulating plate (1510), a sealing gasket (1450), an upper gasket (1460), and a current collector (1300). Since the structure of the current collector (1300) is different and the rest is substantially the same as the first embodiment described above, a repeated description is omitted.

[0128] In this fourth embodiment, the current collecting member (1300) comprises a current collecting plate (1310), a current collecting projection (1320), and an adhesive layer (1330). Since the current collecting plate (1310) and the current collecting projection (1320) are substantially the same as those in the first embodiment described above, a repeated description is omitted.

[0129] A current collecting protrusion (1320) is formed in the center of the upper surface of the current collecting plate (1310), and an adhesive layer (1330) is formed on both sides of the upper surface of the current collecting plate (1310). The adhesive layer (1330) includes an insulating layer (1331) and a heat-fusion layer (1332) formed on the upper and lower surfaces of the insulating layer (1331).

[0130] The heat-fusion layer (1332) comprises a thermoplastic resin that melts when heated. The heat-fusion layer (1332) is formed on the upper and lower surfaces of the insulating layer (1331) and melts and solidifies when heated, so that the current collector plate (1310) and the insulating plate (1510) are heat-fused and joined on the upper and lower surfaces of the insulating layer (1331).

[0131] A modified polyolefin-based resin may be used as the heat-sealable layer (1432), preferably as a copolymer of ethylene or propylene and a monomer having a polar group, such as an ethylene / acrylic acid copolymer, an ethylene / methacrylic acid copolymer, an ethylene / ethyl acrylate copolymer, an ethylene-butyl acrylate copolymer, an ethylene-vinyl acetate copolymer, an ethylene / itaconic acid copolymer, an ethylene / monomethyl maleate copolymer, an ethylene / maleic acid copolymer, an ethylene / acrylic acid / methyl methacrylate copolymer, an ethylene / methacrylic acid / ethyl acrylate copolymer, an ethylene / monomethyl maleate / ethyl acrylate copolymer, an ethylene / methacrylic acid / vinyl acetate copolymer, an ethylene / acrylic acid / vinyl alcohol copolymer, an ethylene / propylene / acrylic acid copolymer, an ethylene / styrene / acrylic acid copolymer. Ethylene / methacrylic acid / acrylonitrile copolymer, ethylene / fumaric acid / vinylmethyl ether copolymer, ethylene / vinyl chloride / acrylic acid copolymer, ethylene / vinylidene chloride / acrylic acid copolymer, ethylene / trifluoroethylene / methacrylic acid copolymer, ethylene / sodium methacrylate salt copolymer, ethylene / zinc acrylate salt copolymer, ethylene / sodium styrene sulfonate salt copolymer, styrene-ethylene-propylene copolymer, propylene / acrylic acid copolymer, propylene / methacrylic acid copolymer, propylene / ethyl acrylate, propylene-butyl acrylate copolymer, propylene-vinyl acetate copolymer, propylene / itaconic acid copolymer, propylene / monomethyl maleate copolymer, propylene / maleic acid copolymer, propylene / acrylic acid / methyl methacrylate Copolymer, Propylene / Methacrylic Acid / Ethyl Acrylate Copolymer, Propylene / Monomethyl Maleate / Ethyl Acrylate Copolymer, Propylene / Methacrylic Acid / Vinyl Acetate Copolymer, Propylene / Acrylic Acid / Vinyl Alcohol Copolymer, Propylene / Propylene / Acrylic Acid Copolymer, Propylene / Styrene / Acrylic Acid Copolymer, Propylene / Methacrylic Acid / Acrylonitrile Copolymer, Propylene / Fumaric Acid / Vinyl Methyl Ether Copolymer, Propylene / Vinyl Chloride / Acrylic Acid Copolymer, Propylene / Vinylidene Chloride / Acrylic Acid Copolymer,Propylene / chlorotrifluoroethylene / methacrylic acid copolymer, propylene / sodium methacrylate salt copolymer, propylene / zinc acrylate salt copolymer, propylene / sodium styrene sulfonate salt copolymer, styrene-propylene-propylene copolymer, and substituted polyolefin resins which are maleic anhydride-grafted polyethylene or polypropylene, may be maleic anhydride-grafted high-density polyethylene (m-HDPE), maleic anhydride-grafted propylene (m-PP), maleic anhydride-grafted polyethylene / propylene copolymer (m-cpp), chlorinated polyethylene, polypropylene (CM), chlorosulfonated polyethylene or polypropylene (CSM).

[0132] When manufacturing a secondary battery, after inserting the current collector protrusion (1320) into the through hole (1410a) and the insertion hole (1420a), and before joining the electrode terminal (1420) and the current collector protrusion (1320) by welding, heat is applied to the cap assembly (CA4) so ​​that the current collector plate (1310) and the insulating plate (1510) are joined by thermal fusion, thereby improving the bonding strength between the current collector member (1300) and the insulating plate (1510).

[0134] FIG. 15 is a top perspective view of an insulating member of a secondary battery according to embodiments of the present invention, FIG. 16 is a bottom perspective view of an insulating member of a secondary battery according to embodiments of the present invention, FIG. 17 is a bottom view of an insulating member of a secondary battery according to embodiments of the present invention, FIG. 18 is a partial cross-sectional view showing a cap plate and an insulating member, and FIG. 19 is a cutaway perspective view showing an embodiment of a guide portion of an insulating member.

[0135] As illustrated in FIGS. 15 to 19, an insulating member (1500) is installed between a cap plate (1410) and an electrode assembly (1200) to insulate the cap plate (1410) and the electrode assembly (1200). The insulating member (1500) may be formed in a shape corresponding to the cap plate (1410) and may be formed in the shape of an elongated rectangular plate. The upper insulating member (1500) may be positioned to face the cap plate (1410) but may be positioned parallel to the cap plate (1410).

[0136] The insulating member (1500) may include an insulating plate (1510) in the shape of a square plate and two supporting protrusions (1520) that protrude downward toward the case (1100) from both edges in the longitudinal direction (y-axis direction) of the insulating plate (1510).

[0137] An insertion hole (1530) into which the body portion (1421) of the electrode terminal (1420) and the sealing gasket (1450) are inserted may be formed in the insulating plate (1510).

[0138] Additionally, the insulating member (1500) may include a guide hole (1511) located at the bottom of the electrolyte injection port (1430), a guide portion (1540) protruding downward from the guide hole (1511), and an exhaust portion (1550) located at the bottom of the vent portion (1440).

[0139] The guide section (1540) may include a guide rim (1541) that surrounds the lower part of the guide hole (1511), a support member (1542) located at the lower part of the guide hole (1511) that partially blocks the guide hole (1511), and an inner hole (1543) formed in the support member (1542) to move fluid. The guide rim (1541) may be formed in the shape of a circular ring, and the support member (1542) may be formed as a straight rod. The support member (1542) is fixed to the lower part of the guide rim (1541) and may extend in the radial direction of the guide hole (1511).

[0140] The inner hole (1543) is located at the longitudinal center of the support (1542) and can be formed to face the electrolyte injection port (1430). The diameter (D3) of the inner hole (1543) is formed to be smaller than the diameter (D1) of the electrolyte injection port (1430), and the inner hole (1543) can be located inside the lower region corresponding to the electrolyte injection port (1430).

[0141] Meanwhile, the diameter (D2) of the guide hole (1511) may be formed larger than the diameter (D1) of the electrolyte injection port (1430). The width (W1) of the support (1542) may be 0.2 to 0.6 times the diameter (D2) of the guide hole (1511). However, the width (W1) of the support (1542) may be formed larger than the diameter (D1) of the electrolyte injection port (1430) and may be 1.1 to 1.5 times the diameter (D1) of the electrolyte injection port (1430).

[0142] A first opening (1544) and a second opening (1545) are formed between the side end of the support (1542) and the inner wall of the guide rim (1541), and the first opening (1544) and the second opening (1545) are open toward the bottom but can be spaced apart with the support (1542) in between.

[0143] The insulating member (1500) is located at the bottom of the cap plate (1410), and the electrolyte is injected into the electrolyte injection port (1430) while the cap plate (1410) is combined with the case (1100). When a guide portion (1540) having a guide rim (1541), a support (1542), and a guide hole (1511) is formed on the insulating member (1500), the electrolyte injection port (1430) is prevented from being blocked by the lower structure and the electrolyte can be easily injected.

[0144] In particular, since the inner hole (1543) is located directly below the electrolyte injection port (1430), the electrolyte can move into the case (1100) through the inner hole (1543) to prevent backflow of the electrolyte, and in the event that the inner hole (1543) is blocked or a large amount of electrolyte is supplied, the electrolyte can be injected into the case through the first opening (1544) and the second opening (1545) formed on both sides of the support (1542).

[0146] FIG. 20 is a cross-sectional view illustrating another embodiment of the guide portion of the insulating member.

[0147] Referring to FIG. 20, an insulating member (1500) has a guide portion (1540_2) formed therein, and the guide portion (1540_2) may include a guide rim (1541) that surrounds the lower part of a guide hole (1511), a support member (1542) located at the lower part of the guide hole (1511) that partially blocks the guide hole (1511), and an inner hole (1543: 1543a, 1543b) formed in the support member (1542) to move fluid.

[0148] The guide rim (1541) may be made of a circular ring, and the support (1542) extends in the diametrical direction of the guide hole (1511), and an inner hole (1543) may be formed in the longitudinal central part of the support (1542).

[0149] The inner hole (1543) has one entrance (1543a) and multiple exits (1543b), and the inner hole (1543) may have two exits (1543b). Additionally, the inner hole (1543) may include an upper passage (1546) extending inward from the upper surface and two lower passages (1547) inclined toward the upper passage (1546).

[0150] According to the guide section (1540_2) configured in this manner, a single passage in the inner hole (1543) branches into multiple directions for injection, thereby allowing for stable injection of the electrolyte and reducing the electrolyte injection speed, which prevents deformation of the separator membrane caused by the electrolyte.

[0152] FIG. 21 is a cross-sectional view illustrating the exhaust portion of an insulating member.

[0153] As illustrated in FIGS. 16 and 21, the exhaust section (1550) is located at the bottom of the vent section (1440) and has a plurality of exhaust openings. The exhaust section (1550) may include a support frame (1512) that protrudes downward and is formed in a ring shape, and a plurality of dividing rods (1554) that are fixed to the support frame (1512) and extend in the width direction (x-axis direction) of the insulating member (1500). A first exhaust opening (1551) is formed in the center of the exhaust section (1550), and a second exhaust opening (1552) and a third exhaust opening (1553) may be formed on both sides of the first exhaust opening (1551). The first exhaust opening (1551) has a larger cross-sectional area than the second exhaust opening (1552) and the third exhaust opening (1553).

[0154] When an exhaust section (1550) is formed in the insulating member (1500) in this manner, when the pressure inside the case (1100) increases, the vent member (1441) breaks at a preset pressure, allowing the gas inside the case (1100) to be easily discharged.

[0156] FIG. 22 is a drawing illustrating the process of combining a foil tab and a current collector in a secondary battery according to one embodiment of the present invention, and FIG. 23 is a drawing illustrating the process of combining a cap assembly and a current collector in a secondary battery according to one embodiment of the present invention.

[0157] As illustrated in FIGS. 22 and 23, foil tabs (1220, 1230) are welded to a current collector (1300). The foil tabs (1220, 1230) may be welded to the current collector (1300) at the bottom of the current collector (1300). The current collector (1300) may be installed on the positive and negative electrodes, respectively. After the foil tabs (1220, 1230) and the current collector (1300) are welded, the current collector (1300) and the cap member (1400) may be joined.

[0158] FIG. 24 is a drawing illustrating the process of combining a current collector and a foil tab when the foil tab is formed in both directions in a secondary battery according to one embodiment of the present invention, and FIG. 25 is a drawing illustrating the process of combining a cap assembly with a current collector.

[0159] In FIGS. 22 and 23, the positive foil tab and the negative foil tab are both formed in the same direction. However, as shown in FIGS. 24 and 25, the electrode assembly may have the positive foil tab and the negative foil tab formed in different directions. Accordingly, the current collector member (1300) may also be coupled to both sides of the electrode assembly (1200).

[0161] FIG. 26 is a drawing illustrating the process of combining a foil tab and a current collector in a secondary battery according to another embodiment of the present invention, and FIG. 27 is a drawing illustrating the process of combining a cap member and a current collector in a secondary battery according to another embodiment of the present invention.

[0162] As illustrated in FIGS. 26 and 27, foil tabs (1220a, 1220b, 1230a, 1230b) are welded onto a current collecting member (1300). On one current collecting member (1300), the foil tabs (1220a, 1220b, 1230a, 1230b) rise up onto the current collecting member from different directions centered around the current collecting projection (1320). The foil tabs (1220a, 1220b, 1230a, 1230b) can be positioned so as not to interfere with each other. The current collecting member (1300) can be installed on the positive and negative electrodes, respectively. At this time, an insulating material is positioned at the bottom of the current collecting member so that the current collecting member and the electrode assembly can be insulated.

[0163] FIG. 28 is a drawing illustrating the process of combining a current collector and a foil tab when a foil tab is formed in both directions in a secondary battery according to another embodiment of the present invention, FIG. 29 is a drawing illustrating the process of combining a cap member with a current collector, and FIG. 30 is a drawing illustrating the process of attaching an insulating member when the electrode assembly and the current collector are combined.

[0164] In FIGS. 26 and 27, the positive foil tab and the negative foil tab are both formed in the same direction. However, as shown in FIGS. 28 and 29, the electrode assembly may have the positive foil tab and the negative foil tab formed in different directions. Accordingly, the current collector member (1300) may also be coupled to both sides of the electrode assembly (1200).

[0165] Meanwhile, as shown in FIG. 30, a first insulating tape (T1) can be attached to the current collector (1300) after the electrode assembly (1200) and the current collector (1300) are combined. This prevents a short circuit between the foil tab and the cap member (1400).

[0166] After attaching the first insulating tape (T1), the outer surface of the electrode assembly (1200) is wrapped with the second insulating tape (T2), and then the electrode assembly (1200) can be inserted into the case (1100).

[0167] Next, the outer surface of the case (1100) can be wrapped with a third insulating tape (T3) to complete the manufacture of the secondary battery.

[0169] FIG. 31 is a drawing showing a secondary battery including two electrode portions according to another embodiment of the present invention, and FIG. 32 is a drawing showing a foil tab formed on two electrode portions according to another embodiment of the present invention joined to a current collector member.

[0170] As illustrated in FIGS. 31 and 32, a secondary battery (1000) according to another embodiment of the present invention includes a case (1100), an electrode assembly (1200), a current collector (1300), and a cap member (1400).

[0171] The electrode portion (1210) of the electrode assembly (1200) is provided with a first electrode portion (1210_1) and a second electrode portion (1210_2). A first foil tab (1220_1) and a second foil tab (1230_1) are formed in the first electrode portion (1210_1), and a first foil tab (1220_2) and a second foil tab (1230_2) are formed in the second electrode portion (1210_2). The first foil tab (1220_1) of the first electrode portion (1210_1) and the second electrode portion (1210_2) are joined to a single identical current collecting member (1300_1). The second foil tab (1230_1) of the first electrode part (1210_1) and the second foil tab (1230_2) of the second electrode part (1210_2) are joined to one identical current collecting member (1300_2).

[0172] In this embodiment, the first electrode part (1210_1) and the second electrode part (1210_2) are taped together with the fourth insulating tape (T4) and the fifth insulating tape (T5). The fourth insulating tape (T4) is attached to the height-direction side of the electrode assembly (1200), and the fifth insulating tape (T5) is attached to the length-direction side of the electrode assembly (1200).

[0173] When n fourth or fifth insulating tapes (T4, T5) are attached to one side, the fourth and fifth insulating tapes (T4, T5) may be attached at points that divide the length of the attached side into (n+1) equal parts. For example, as shown in FIG. 31, when one fourth insulating tape (T4) is attached to one side in the height direction, the fourth insulating tape (T4) is attached at a point that divides the side in the height direction of the electrode assembly (1200) into two equal parts. When two fifth insulating tapes (T5) are attached to one side in the length direction, the fifth insulating tapes (T5) are attached at two points that divide the side in the length direction of the electrode assembly (1200) into three equal parts. In this embodiment, there is one fourth insulating tape (T4) and two fifth insulating tapes (T5), but this is not limited thereto. The fourth insulating tape (T4) and the fifth insulating tape (T5) serve to bind the first electrode part (1210_1) and the second electrode part (1210_2) together, and also provide an insulating effect.

[0174] After the electrode assembly (1200) is taped with the fourth and fifth insulating tapes (T4, T5), a sixth insulating tape (T6) may be attached to wrap all remaining surfaces except for the sides where foil tabs (1220_1, 1220_2, 1230_1, 1230_2) are formed for insulation from the case (1100). Afterward, the electrode assembly (1200) is inserted into the case (1100), and a cap member (1400) is attached to the opening of the case (1100).

[0176] Although embodiments of the present invention have been described above, those skilled in the art may modify and change the present invention in various ways by adding, changing, deleting, or adding components, etc., without departing from the spirit of the present invention as described in the claims, and such modifications and changes are also to be included within the scope of the rights of the present invention. Explanation of the symbols

[0177] 1000 : Secondary battery 1100 : Case 1200 : Electrode assembly 1210 : Electrode part 1220, 1230 : Foil tap 1300 : Current collector missing 1310 : Collection plate 1320 : Collection projection 1321 : 1st collecting process 1322 : 2nd collecting process 1400 : Cap missing 1410 : Cap plate 1420 : Electrode terminal 1430: Electrolyte inlet 1440: Vent 1450: Sealing gasket 1460: Upper gasket 1500: Insulating member 1510: Insulating plate 1520 : Support projection 1530 : Insertion hole 1540: Guide section 1550: Exhaust section

Claims

Claim 1 A case having an opening formed therein; an electrode assembly inserted into the case through the opening and having an electrode portion and a plurality of foil tabs formed on the electrode portion; and a cap assembly sealing the opening of the case into which the electrode assembly is inserted; wherein the cap assembly comprises: a cap plate having a through hole formed therein; an upper gasket disposed on the upper part of the cap plate; an insulating plate disposed on the lower part of the cap plate; an electrode terminal disposed on the upper part of the upper gasket and having an insertion hole formed therein; a current collecting member having a current collecting plate and a current collecting projection formed on the upper surface of the current collecting plate, inserted into the insertion hole, and coupled to the upper end of the electrode terminal. A secondary battery comprising: a sealing gasket interposed between the through hole and the current collecting projection; wherein the current collecting projection includes a first current collecting projection formed on the upper surface of the current collecting plate and having a first diameter, and a second current collecting projection formed on the upper surface of the first current collecting projection and having a second diameter smaller than the first diameter, wherein a fitting groove is formed on the lower surface of the electrode terminal, and a fitting projection that fits into the fitting groove is formed on the upper surface of the first current collecting projection. Claim 2 A secondary battery according to claim 1, characterized in that the current collector plate is positioned to be in contact with the lower surface of the sealing gasket and the insulating plate. Claim 3 delete Claim 4 A secondary battery according to claim 1, characterized in that the step formed by the first current collecting projection and the second current collecting projection engages with the step formed by the sealing gasket and the lower surface of the electrode terminal. Claim 5 A secondary battery according to claim 1, characterized in that a groove is formed on the upper surface of the second current collector projection. Claim 6 A secondary battery according to claim 5, wherein the groove is formed in a truncated cone shape or a hemispherical shape. Claim 7 A secondary battery according to claim 1, wherein the cap plate has a seating surface formed around the through hole and a stepped surface protruding from the outside of the seating surface, and the upper gasket is interposed between the cap plate and the electrode terminal. Claim 8 A secondary battery according to claim 7, wherein the upper gasket comprises a first horizontal surface formed with a first thickness and formed to contact the seating surface of the cap plate, a second horizontal surface formed with a second thickness thicker than the first thickness and formed to contact the seating surface and the stepped surface, and a vertical surface extending vertically from the outer end of the second horizontal surface to surround the outer surface of the electrode terminal. Claim 9 A secondary battery according to claim 2, wherein a first alignment projection is formed on the lower surface of the through hole side of the cap plate in a shape connected to the through hole, and a first alignment groove is formed in the sealing gasket at a position corresponding to the first alignment projection. Claim 10 delete Claim 11 A secondary battery according to claim 1, wherein the fitting groove is formed in a stepped portion formed by the first current collecting projection and the second current collecting projection, and the fitting projection is formed at a position corresponding to the fitting groove on the upper surface of the first current collecting projection located outside the second current collecting projection. Claim 12 A secondary battery according to claim 1, characterized in that a first undercut is formed at the bottom of the sealing gasket, and a first inclined surface having a shape corresponding to the first undercut is formed at the bottom of the first current collecting projection. Claim 13 A secondary battery according to claim 12, characterized in that a second undercut is formed on the lower surface of the insertion hole side of the electrode terminal, and a second inclined surface having a shape corresponding to the second undercut is formed on the lower end of the second current collecting projection. Claim 14 A secondary battery comprising: a case having an opening formed therein; an electrode assembly inserted into the case through the opening and having an electrode portion and a plurality of foil tabs formed on the electrode portion; and a cap assembly sealing the opening of the case into which the electrode assembly is inserted; wherein the cap assembly comprises: a cap plate having a through hole formed therein; an upper gasket disposed on the upper part of the cap plate; an insulating plate disposed on the lower part of the cap plate; an electrode terminal disposed on the upper part of the upper gasket and having an insertion hole formed therein; a current collecting member having a current collecting projection formed on the upper surface of the current collecting plate, inserted into the insertion hole, and coupled to the upper end of the electrode terminal; and a sealing gasket interposed between the through hole and the current collecting projection; wherein the current collecting projection is formed in the center of the upper surface of the current collecting plate, and an adhesive layer including a heat-fusion layer is formed on both sides of the upper surface of the current collecting plate. Claim 15 A secondary battery according to claim 1, comprising an insulating member disposed between the cap plate and the electrode assembly and having the insulating plate, wherein the insulating member comprises a guide hole located below an electrolyte injection port formed in the cap plate and a guide portion protruding downward from the guide hole to guide the movement of the electrolyte. Claim 16 A secondary battery according to claim 15, wherein the guide portion comprises a support located at the lower part of the guide hole and partially blocking the guide hole, and an internal hole formed in the support to move fluid. Claim 17 A secondary battery according to claim 16, wherein the guide portion includes a guide rim that surrounds the lower part of the guide hole, the support member is fixed to the guide rim, and a first opening and a second opening are formed between the side end of the support member and the inner wall of the guide rim. Claim 18 A secondary battery according to claim 15, wherein the cap plate has a vent portion formed for gas discharge, the insulating member includes an exhaust portion protruding toward the bottom of the case and having a plurality of discharge openings, and the exhaust portion is located below the vent portion. Claim 19 A secondary battery according to claim 1, wherein the plurality of foil tabs are formed in one direction of the electrode assembly. Claim 20 A secondary battery according to claim 1, characterized in that the plurality of foil tabs are formed in both directions of the electrode assembly. Claim 21 A secondary battery according to claim 1, characterized in that after the electrode assembly and the current collector plate are combined, a first insulating tape is attached to the current collector plate, and after the outer surface of the electrode assembly is wrapped with a second insulating tape, the electrode assembly is inserted into the case, and the outer surface of the case into which the electrode assembly is inserted is wrapped with a third insulating tape.

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