Secondary battery

Abstract

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 via the opening and includes 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 has been inserted. In addition, the cap assembly includes a cap plate, a lower insulation plate, and an electrode terminal. A through-hole is formed in the cap plate. The lower insulation plate is disposed below the cap plate and has a protrusion formed at an inner end thereof. The electrode terminal is disposed on the cap plate, is inserted into the through-hole, and has a first fitting groove formed on an outer surface thereof, into which the protrusion is fitted.

Description

secondary battery

[0001] The present invention relates to a secondary battery. The present application is filed with the Korean Intellectual Property Office on February 10, 2025, and is based on Korean Patent Application No. 10-2025-0016994, the contents of which are incorporated in whole into the present application by reference herein, and claims priority thereof.

[0002] Secondary batteries, which offer high applicability across product categories and possess electrical characteristics such as high energy density, are widely applied not only to portable devices but also to electric vehicles (EVs) and hybrid electric vehicles (HEVs) powered by electric driving 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 sheets. Can-type secondary batteries can be classified into cylindrical secondary batteries and prismatic secondary batteries depending on the shape of the metal can.

[0006] The present invention provides a secondary battery comprising a cap assembly that can reduce the overall resistance of the secondary battery, improve space utilization, and improve sealing by preventing the welded portion from being exposed to the outside.

[0007] 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. Furthermore, the cap assembly includes a cap plate, a lower insulating plate, and an electrode terminal. A through hole is formed in the cap plate. The lower insulating plate is positioned at the bottom of the cap plate and has a protrusion formed at its inner end. The electrode terminal is positioned at the top of the cap plate and is inserted into the through hole, and a first fitting groove is formed on its outer surface into which the protrusion is fitted.

[0008] The above electrode terminal includes a terminal body and a terminal projection. The terminal body is formed on the upper surface of a cap plate. The terminal projection protrudes from the lower surface of the terminal body and is inserted into a through hole. An insertion groove into which a current collecting projection is inserted is formed in an upwardly recessed shape in the center of the terminal projection. A first fitting groove is formed on the outer surface of the terminal projection.

[0009] A rigid reinforcing insert may be formed within the lower insulating plate.

[0010] One end of the above rigid reinforcing insert may be located within the protrusion.

[0011] A second fitting groove is formed on the inner surface of the above-mentioned insertion groove, and a fitting part that fits into the second fitting groove may be formed on the outer surface of the current collection projection.

[0012] The above-mentioned current collection protrusion may be formed in a cylindrical shape, with the diameter decreasing from the bottom to the top.

[0013] The lower diameter of the above-mentioned current collection projection can be formed to be larger than the diameter of the insertion groove.

[0014] It includes an upper insulating plate formed on the upper part of the above cap plate, and a sealing gasket may be interposed between the upper insulating plate and the terminal protrusion.

[0015] The upper surface of the above insertion groove can be formed at a position higher than the upper insulating plate.

[0016] The terminal projection end of the sealing gasket can be formed to extend from the lower surface of the terminal body to the protrusion.

[0017] The sealing gasket above can be formed into a wavy meander shape.

[0018] After the current collection protrusion is inserted into the above insertion groove, welding can be performed on the upper surface of the electrode terminal to combine the electrode terminal and the current collection protrusion.

[0019] The above plurality of foil tabs can be formed in one direction of the electrode assembly.

[0020] The above plurality of foil tabs can be formed in both directions of the electrode assembly.

[0021] After the electrode assembly and the current collector plate are combined, a first insulating member may be attached to the current collector plate. Then, after the outer surface of the electrode assembly is wrapped with a second insulating member, 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 member.

[0022] According to another embodiment of the present invention, a vehicle comprising the secondary battery is provided.

[0023] A cap assembly according to another embodiment of the present invention is a structure for sealing an opening of a secondary battery case, wherein the cap assembly comprises: a cap plate having a through hole formed therein; a lower insulating plate disposed below the cap plate and having a protrusion formed at an inner end; and an electrode terminal disposed above the cap plate, inserted into the through hole, and having a first fitting groove formed on its outer surface into which the protrusion is fitted.

[0024] The electrode terminal comprises a terminal body formed on the upper part of the cap plate and a terminal projection that protrudes from the lower surface of the terminal body, is inserted into the through hole, has an insertion groove formed upwardly in the center into which a current collecting projection is inserted, and has the first fitting groove formed on its outer surface.

[0025] The above cap assembly includes an upper insulating plate formed on the upper part of the cap plate, and a sealing gasket is interposed between the upper insulating plate and the terminal projection.

[0026] The terminal projection side end of the sealing gasket is formed to extend from the lower surface of the terminal body to the projection.

[0027] According to the present invention, the overall resistance of a secondary battery can be reduced, space utilization can be improved, and sealing can be improved by preventing the welded part from being exposed to the outside.

[0028] The following drawings attached to this specification illustrate embodiments of the present invention and serve to further enhance understanding of the technical concept of the present invention together with the detailed description of the invention provided below; therefore, the present invention should not be interpreted as being limited only to the matters described in such drawings.

[0029] FIG. 1 is a cross-sectional view showing a cap assembly according to the prior art.

[0030] FIG. 2 is a perspective view showing a secondary battery according to one embodiment of the present invention.

[0031] FIG. 3 is a perspective view showing an exploded cap assembly in a secondary battery according to one embodiment of the present invention.

[0032] 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.

[0033] FIG. 5 is a drawing showing a first electrode plate in a secondary battery according to one embodiment of the present invention.

[0034] FIG. 6 is a drawing showing a second electrode plate in a secondary battery according to one embodiment of the present invention.

[0035] FIGS. 7 and FIGS. 8 are cross-sectional views illustrating a cap assembly according to a first embodiment of the present invention.

[0036] FIG. 9 is a cross-sectional view showing a cap assembly according to a second embodiment of the present invention.

[0037] FIG. 10 is a cross-sectional view showing a cap assembly according to a third embodiment of the present invention.

[0038] FIG. 11 is a cross-sectional view showing a cap assembly according to a fourth embodiment of the present invention.

[0039] FIG. 12 is a drawing illustrating the process of combining a foil tab and a current collector plate in a secondary battery according to one embodiment of the present invention.

[0040] FIG. 13 is a drawing illustrating the process of combining a cap assembly and a current collector plate in a secondary battery according to one embodiment of the present invention.

[0041] FIG. 14 is a drawing illustrating the process of combining a current collector plate 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.

[0042] Figure 15 is a drawing illustrating the process of combining a cap assembly with a collector plate.

[0043] FIG. 16 is a drawing illustrating the process of attaching an insulating member while the electrode assembly and the current collector plate are combined.

[0044] FIG. 17 is a schematic perspective view of an automobile including a secondary battery according to one embodiment of the present invention.

[0045] In parts of the attached drawings, corresponding components are given the same reference numerals. Those skilled in the art understand that the drawings are intended to illustrate elements simply and clearly and are not necessarily drawn to scale. For example, to aid in understanding various embodiments, the dimensions of some elements depicted in the drawings may be exaggerated compared to others. Additionally, elements of known technology that are useful or essential in commercially viable embodiments may often be omitted so as not to hinder the spirit of the various embodiments of the present invention.

[0046] 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.

[0047] 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.

[0048] Hereinafter, embodiments of the present invention will be described with reference to the attached drawings.

[0049] In a prismatic secondary battery, an electrode assembly is housed within a metal case, and a cap assembly is attached to the open end.

[0050] FIG. 1 is a cross-sectional view showing a cap assembly according to the prior art.

[0051] As shown in FIG. 1, a cap assembly (10) according to the prior art is manufactured by inserting a current collecting projection (13) of a current collecting plate (12) into the hollow of a rivet (11), and then welding (W) the upper end (11a) of the rivet (11) and the upper end (13a) of the current collecting projection (13).

[0052] In the cap assembly (10) according to this conventional technology, rivets (11) are used to connect the electrode terminal (14) and the cap plate (15), which increases the number of parts and consequently increases the overall resistance of the secondary battery, and the space utilization may be reduced due to the rivets (11).

[0053] In addition, the gap in the welded portion (W) may be exposed to the outside, and the electrolyte or gas inside the case may leak out through the exposed welded portion (W), and external moisture or air may penetrate into the case, which may degrade the efficiency of the battery.

[0054] Considering these points, the present invention provides a technology that can reduce the overall resistance of a secondary battery and improve space utilization by forming a heat-fused layer between, for example, electrode terminals in a cap assembly instead of using rivets, and improve sealing by preventing the welded area from being exposed to the outside.

[0055] FIG. 2 is a perspective view showing a secondary battery according to an embodiment of the present invention, FIG. 3 is a perspective view showing an exploded cap assembly in a secondary battery according to an 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 an embodiment of the present invention, FIG. 5 is a drawing showing a first electrode plate in a secondary battery according to an embodiment of the present invention, and FIG. 6 is a drawing showing a second electrode plate in a secondary battery according to an embodiment of the present invention.

[0056] As illustrated in FIGS. 2 and 3, a secondary battery (1000) according to one embodiment of the present invention includes a case (1100), an electrode assembly (1200), a current collector plate (1300), and a cap assembly (1400).

[0057] 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.

[0058] 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.

[0059] The electrode assembly (1200) is housed inside the case (1100). As illustrated in FIG. 4, the electrode assembly (1200) according to one embodiment 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.

[0060] As shown in FIGS. 5 and 6, the electrode portion (1210) comprises a plurality of first electrode plates (1211), a plurality of second electrode plates (1212), and a separator.

[0061] 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.

[0062] A separator (not shown) 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.

[0063] The electrode portion (1210) can be formed by positioning a separator between a first electrode plate (1211) and a second electrode plate (1212) that are arranged sequentially. In one embodiment, the electrode portion (1210) can be formed by stacking the first electrode plate (1211), the separator, the second electrode plate (1212), and the separator in the order of tens to hundreds of times.

[0064] 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.

[0065] A foil tab (1220, 1230) without active material 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). A plurality of foil tabs (1220, 1230) may be formed in a direction toward the cap assembly (1400).

[0066] 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. For example, 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 (1211, 1212), and the plurality of first foil tabs (1220) and the plurality of second foil tabs (1230) grouped together may be spaced apart in the longitudinal direction of the electrode assembly (1200).

[0067] Multiple foil tabs (1220, 1230) overlapped at each location can be connected to a current collector plate, such as by ultrasonic welding or laser welding, to facilitate the movement of current.

[0068] The collector plate (1300) is equipped with a collector body (1310) and a collector projection (1320).

[0069] A plurality of foil tabs (1220, 1230) are bent and welded to the current collecting body (1310). A current collecting projection (1320) is formed in the center of the current collecting body (1310).

[0070] The current collecting projection (1320) protrudes upward from the upper surface of the current collecting body (1310) and is coupled to the electrode terminal (1420) by welding or the like at the upper surface (1421a) of the insertion groove (1421) of the electrode terminal (1420) to electrically connect the electrode assembly and the electrode terminal (1420) (see FIG. 8). In another embodiment, the current collecting projection (1320) of the current collecting body (1310) is coupled to the terminal projection (1422, see FIG. 9) of the electrode terminal (1420) to electrically connect the electrode assembly (1200) and the electrode terminal (1420).

[0071] The current collector plate (1300) may be made of the same material as the plurality of foil tabs (1220, 1230) and may have a predetermined thickness, for example, about 0.8 mm to 1.2 mm. By using a current collector plate with a thick thickness, insulation effects and damage to the separator can be prevented or suppressed.

[0072] An insulating material may be placed on the lower part of the current collector plate (1300). The insulating material may be an insulating plate or an insulating film.

[0073] After welding multiple first foil tabs (1220) together and multiple second foil tabs (1230) together, a current collector plate (1300) is placed on each of the first foil tabs (1220) and the second foil tabs (1230).

[0074] After bending a plurality of first foil tabs (1220) and a plurality of second foil tabs (1230), a collector plate (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.

[0075] The cap assembly (1400) seals the opening of a case (1100) in which an electrode assembly (1200) is housed. In the present invention, the cap assembly (1400) is provided to reduce the overall resistance of the secondary battery, improve space utilization, and enhance sealing by preventing the welded portion from being exposed to the outside. Various embodiments of such a cap assembly (1400) will be described in detail with reference to FIGS. 7 through 11.

[0076]

[0077] FIGS. 7 and FIGS. 8 are cross-sectional views illustrating a cap assembly according to a first embodiment of the present invention, FIG. 7 is a cross-sectional view illustrating a state in which the current collector plate (1300) is omitted, and FIG. 8 is a cross-sectional view illustrating a state in which the current collector plate (1300) is combined.

[0078] As illustrated in FIGS. 7 and 8, a cap assembly (1400_1) according to a first embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), a lower insulating plate (1430), a sealing gasket (1440), and an upper insulating plate (1450). The electrode terminal (1420) and the lower insulating plate (1430) may be fastened together, and a current collector plate (1300) may be coupled to the electrode terminal (1420) without rivets to form a cap assembly.

[0079] 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.

[0080] A vent portion (1411) and an electrolyte injection port (1412) may be formed in the cap plate (1410). The vent portion (1411) opens when the internal pressure of the case (1100) exceeds a reference value. In this embodiment, the vent portion (1411) is formed in the cap plate (1410), but in other embodiments, the vent portion (1411) may be formed in the case (1100). Electrolyte can be injected into the interior of the case (1100) through the electrolyte injection port (1412).

[0081] The electrode terminal (1420) can be formed on the upper part of the cap plate (1410). The electrode terminal (1420) is electrically connected to the foil tabs (1220, 1230) through the current collector plate (1300).

[0082] The electrode terminal (1420) may include a terminal body (1421) and a terminal projection (1422).

[0083] The terminal body (1421) can be in the shape of a circular or square plate.

[0084] The terminal projection (1422) is formed to protrude downward for a predetermined length from the lower surface of the terminal body (1421). An insertion groove (1423) having a predetermined diameter is formed in the center of the terminal projection (1422). The insertion groove (1423) is formed by the central part of the terminal projection (1422) being sunken upward. The upper surface (1423a) of the insertion groove (1423) is formed at a position higher than the upper insulating plate (1450). Additionally, a first fitting groove (1424a) is formed on the outer surface of the terminal projection (1422). A current collecting projection (1320) can be inserted into the insertion groove (1423).

[0085] A lower insulating plate (1430) may be positioned at the bottom of a cap plate (1410). A protrusion (1431) is formed at the inner end of the lower insulating plate (1430). The protrusion (1431) protrudes toward the terminal projection (1422) and is fitted into a first fitting groove (1424a) formed on the outer surface of the terminal projection (1422). This lower insulating plate (1430) can insulate the cap plate (1410) and the current collector plate (1300) while performing the function of a rivet to fix the electrode terminal (1420) to the cap assembly (1400_1).

[0086] An upper insulating plate (1450) may be disposed between the electrode terminal (1420) and the cap plate (1410). The upper insulating plate (1450) insulates the electrode terminal (1420) and the cap plate (1410).

[0087] A first step (1451) may be formed at the outer end of the upper insulating plate (1450), and a second step (1425) corresponding to the first step (1451) may be formed at the outer end of the electrode terminal (1420). As the second step (1425) is fitted into the first step (1451), the electrode terminal (1420) and the upper insulating plate (1450) can be easily joined.

[0088] Additionally, a sealing gasket (1440) may be disposed at the inner end of the upper insulating plate (1450). For example, the sealing gasket (1440) may be interposed between the inner end of the upper insulating plate (1450) and the outer surface of the terminal projection (1422).

[0089] The sealing gasket (1440) prevents or suppresses the leakage of electrolyte or gas inside the case (1100) to the outside, and prevents or suppresses moisture or air from the outside from penetrating into the case (1100). At this time, the terminal projection side end of the sealing gasket (1440) is formed to extend from the lower surface of the terminal body (1421) to the protrusion (1431) to further improve sealing.

[0090] The sealing gasket (1440) can be formed in a meandering shape. By forming the sealing gasket (1440) in a meandering shape, it can cushion the horizontal stress applied by the upper insulating plate (1450).

[0091] After configuring the cap assembly (1400_1) as shown in FIG. 7, the current collecting projection (1320) of the current collecting plate (1300) is inserted into the insertion groove (1423), and then welding (W) is performed on the upper surface of the electrode terminal (1420) (e.g., the upper surface of the electrode body (1421)) as shown in FIG. 8 to combine the electrode terminal (1420) and the current collecting projection (1320).

[0092] According to the cap assembly (1400_1) according to the first embodiment of the present invention configured as described above, the lower insulating plate (1430) can perform a rivet function to fix the electrode terminal (1420) to the cap assembly (1400_1) while insulating the cap plate (1410) and the current collector plate (1300). For example, the protrusion (1431) of the lower insulating plate (1430) is fitted into the first fitting groove (1424a) of the terminal projection (1422) and fastened, thereby replacing the rivet function and reducing the number of parts forming the cap assembly (1400_1). Accordingly, the overall resistance of the secondary battery can be reduced and space utilization can be improved. In addition, since welding is performed on the upper surface of the electrode terminal (1420), there is no gap in the welded area and it is not exposed to the outside, thereby improving sealing performance.

[0093]

[0094] FIG. 9 is a cross-sectional view showing a cap assembly according to a second embodiment of the present invention.

[0095] Referring to FIG. 9, a cap assembly (1400_2) according to a second embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), a lower insulating plate (1430), a sealing gasket (1440), an upper insulating plate (1450), and a rigid reinforcing insert (1460).

[0096] In this second embodiment, the cap plate (1410), electrode terminal (1420), lower insulation plate (1430), sealing gasket (1440), and upper insulation plate (1450) are substantially the same as those in the first embodiment described above, so a repeated description is omitted.

[0097] The upper and lower insulating plates (1430, 1450) are made of plastic materials such as polypropylene (PP), polyamide (PA), and polycarbonate (PC) that have high insulation and durability, and the negative terminal of the electrode terminal (1420) is made of copper or nickel-plated copper, and the positive terminal is made of metal materials such as aluminum or nickel-plated aluminum.

[0098] In the first embodiment described above, since the protrusion (1431) of the lower insulating plate (1430) made of plastic is fitted into the first fitting groove (1424a) of the terminal projection (1422) made of metal by a press fit method, the durability of the protrusion (1431) portion of the lower insulating plate (1430) may be weakened.

[0099] To prevent or suppress this, in the second embodiment, a rigid reinforcing insert (1460) that reinforces the mechanical strength of the lower insulating plate (1430) may be formed within the lower insulating plate (1430).

[0100] The rigid reinforcing insert (1460) can be made of metal components such as stainless steel, aluminum, and copper.

[0101] Alternatively, the rigid reinforcing insert (1460) may be made of fiber reinforced plastic (FRP), which has high strength and light weight but excellent electrical insulation, or ceramic reinforcement, which has excellent high-temperature durability and excellent electrical insulation.

[0102] Since the rigidity reinforcing insert (1460) is intended to reinforce the rigidity of the protrusion (1431), according to one embodiment, one end of the rigidity reinforcing insert (1460) may be located within the protrusion (1431), and the other end may be located at a predetermined lower position of the cap plate (1410).

[0103]

[0104] FIG. 10 is a cross-sectional view showing a cap assembly according to a third embodiment of the present invention.

[0105] Referring to FIG. 10, the cap assembly (1400_3) according to the third embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), a lower insulating plate (1430), a sealing gasket (1440), and an upper insulating plate (1450). Since the shape of the terminal projection (1422) and the current collection projection (1320) is different, and the rest is substantially the same as the first embodiment described above, a repeated description is omitted.

[0106] In the third embodiment, a second fitting groove (1424b) is formed on the inner surface of the insertion groove (1423) formed in the center of the terminal projection (1422), and a fitting part (1321) that fits into the second fitting groove (1424b) may be formed on the outer surface of the current collection projection (1320).

[0107] The second fitting groove (1424b) can be formed in a sloping shape that is narrower at the top and wider at the bottom, becoming smaller from the bottom to the top of the terminal projection (1422). Additionally, the fitting portion (1321) can be formed in a shape corresponding to the second fitting groove (1424b).

[0108] After configuring the cap assembly (1400_3) as shown in Fig. 10, the current collecting projection (1320) of the current collecting plate (1300) is inserted into the insertion groove (1423), and then welding (W) is performed on the upper surface of the electrode terminal (1420) to combine the electrode terminal (1420) and the current collecting projection (1320).

[0109] At this time, since the fitting part (1321) of the current collector projection (1320) is welded in a state where it is fitted into the second fitting groove (1424b) of the terminal projection (1422), the bonding strength between the current collector plate (1300) and the electrode terminal (1420) can be improved.

[0110] In addition, since the fitting part (1321) and the second fitting groove (1424b) are formed in a slanted shape that is narrower at the top and wider at the bottom, friction between the fitting part (1321) and the insertion groove (1423) is minimized when the current collection projection (1320) is forcibly fitted into the insertion groove (1423), and the fitting operation can be made easier.

[0111]

[0112] FIG. 11 is a cross-sectional view showing a cap assembly according to a fourth embodiment of the present invention.

[0113] Referring to FIG. 11, the cap assembly (1400_4) according to the fourth embodiment of the present invention may include a cap plate (1410), an electrode terminal (1420), a lower insulating plate (1430), a sealing gasket (1440), and an upper insulating plate (1450). Since the shape of the current collector protrusion (1320) is different, and the rest is substantially the same as the first embodiment described above, a repeated description is omitted.

[0114] In the fourth embodiment, the current collecting projection (1320) may be formed in a cylindrical shape having a cross-section that is narrower at the top and wider at the bottom. For example, the current collecting projection (1320) may be formed in a cylindrical shape in which the diameter decreases from the bottom to the top.

[0115] On the other hand, the insertion groove (1423) may be formed with the same diameter at the top and bottom. At this time, the current collecting projection (1320) may be inserted into the insertion groove (1423) in a press-fit manner.

[0116] After configuring the cap assembly (1400_4) as shown in Fig. 11, the current collecting projection (1320) of the current collecting plate (1300) is inserted into the insertion groove (1423), and then welding (W) is performed on the upper surface of the electrode terminal (1420) to combine the electrode terminal (1420) and the current collecting projection (1320).

[0117] At this time, the current collection protrusion (1320) is welded while inserted into the insertion groove (1423) in a press-fit manner, so the bonding strength between the current collection plate (1300) and the electrode terminal (1420) can be improved.

[0118]

[0119] FIG. 12 is a drawing illustrating the process of combining a foil tab and a current collector plate in a secondary battery according to one embodiment of the present invention, and FIG. 13 is a drawing illustrating the process of combining a cap assembly and a current collector plate in a secondary battery according to one embodiment of the present invention.

[0120] As illustrated in FIGS. 12 and 13, foil tabs (1220, 1230) are welded onto a current collector plate (1300). On one current collector plate (1300), the foil tabs (1220, 1230) rise up onto the current collector plate (1300) from different directions centered around the current collector projection (1320). The foil tabs (1220, 1230) can be positioned so as not to interfere with each other. Accordingly, the welding location of the foil tabs (1220, 1230) can be between the current collector plate (1300) and the insulating member of the cap assembly (1400).

[0121] The current collector plate (1300) can be installed on each of the positive and negative electrodes. At this time, an insulating member is located at the bottom of the current collector plate so that the current collector plate and the electrode assembly are insulated.

[0122]

[0123] FIG. 14 is a drawing illustrating the process of combining a current collector plate and a foil tab when foil tabs are formed in both directions in a secondary battery according to one embodiment of the present invention, FIG. 15 is a drawing illustrating the process of combining a cap assembly with a current collector plate, and FIG. 16 is a drawing illustrating the process of attaching an insulating member when the electrode assembly and the current collector plate are combined.

[0124] In FIGS. 12 and 13, the positive foil tab and the negative foil tab are both formed in the same direction. However, as shown in FIGS. 14 and 15, the electrode assembly may have the positive foil tab and the negative foil tab formed in different directions. Accordingly, the current collector plate (1300) may also be attached to both sides of the electrode assembly (1200).

[0125] Meanwhile, as shown in FIG. 16, a first insulating member (I1) 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 assembly (1400).

[0126] After attaching the first insulating member (I1), the outer surface of the electrode assembly (1200) is wrapped with the second insulating member (I2), and then the electrode assembly (1200) can be inserted into the case (1100).

[0127] Next, the manufacturing of the secondary battery can be completed by wrapping the outer surface of the case (1100) with a third insulating member (I3). Here, the first to third insulating members (I1 to I3) may be insulating tape, etc.

[0128] FIG. 17 is a schematic perspective view of an automobile including a secondary battery according to one embodiment of the present invention.

[0129] Referring to FIG. 17, a vehicle (30) according to one embodiment of the present invention may include one or more battery packs (20) comprising one or more secondary batteries according to the aforementioned embodiments. The vehicle (30) according to the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle. The vehicle (30) includes various types of vehicles, such as four-wheeled vehicles, two-wheeled vehicles, or three-wheeled vehicles. The vehicle (30) may operate by receiving power from the battery pack (20) according to one embodiment of the present invention.

[0130] 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.

Claims

1. A case in which an opening is formed; 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 It includes a cap assembly that seals the opening of the case into which the electrode assembly is inserted; wherein the cap assembly is Cap plate with a through hole formed therein; A lower insulating plate disposed at the lower part of the above-mentioned cap plate and having a protrusion formed at its inner end; and A secondary battery comprising: an electrode terminal disposed on the upper part of the cap plate, inserted into the through hole, and having a first fitting groove formed on its outer surface into which the protrusion is fitted.

2. In Paragraph 1, The above electrode terminal is A terminal body formed on the upper part of the above-mentioned cap plate, and A secondary battery comprising a terminal projection that protrudes from the lower surface of the terminal body and is inserted into the through hole, and has an insertion groove formed upwardly in the center into which a current collecting projection is inserted, and has a first fitting groove formed on the outer surface.

3. In Paragraph 1, A secondary battery in which a rigid reinforcing insert is formed within the lower insulating plate.

4. In Paragraph 3, One end of the above rigid reinforcing insert is located within the protrusion of the electrode lower insulating plate of the secondary battery.

5. In Paragraph 2, A secondary battery having a second fitting groove formed on the inner surface of the insertion groove of the electrode terminal, and a fitting part formed on the outer surface of the current collecting projection that fits into the second fitting groove.

6. In Paragraph 2, The above-mentioned current collection protrusion is formed in a cylindrical shape with a cross-section that becomes smaller in diameter from the bottom to the top, in a secondary battery.

7. In Paragraph 6, A secondary battery in which the lower diameter of the above-mentioned current collection protrusion is formed to be larger than the diameter of the above-mentioned insertion groove.

8. In Paragraph 2, It includes an upper insulating plate formed on the upper part of the above cap plate, and A secondary battery having a sealing gasket interposed between the upper insulating plate and the terminal projection.

9. In Paragraph 8, A secondary battery in which the upper surface of the insertion groove is formed at a position higher than the upper insulating plate.

10. In Paragraph 8, A secondary battery in which the terminal projection-side end of the sealing gasket is formed extending from the lower surface of the terminal body to the projection.

11. In Paragraph 8, The above sealing gasket is a secondary battery formed in a wavy meander shape.

12. In Paragraph 2, A secondary battery in which, after the current collecting projection is inserted into the insertion groove, welding is performed on the upper surface of the electrode terminal to combine the electrode terminal and the current collecting projection.

13. In Paragraph 1, The plurality of foil tabs above are formed in one direction of the electrode assembly, forming a secondary battery.

14. In Paragraph 1, The plurality of foil tabs above are formed in both directions of the electrode assembly in a secondary battery.

15. In Paragraph 1, After the electrode assembly and the current collector plate are combined, a first insulating material is attached to the current collector plate, and After the outer surface of the electrode assembly is wrapped with a second insulating material, the electrode assembly is inserted into the case, and A secondary battery characterized in that the outer surface of the case into which the electrode assembly is inserted is wrapped with a third insulating material.

16. An automobile comprising the secondary battery of paragraph 1.

17. A cap assembly for sealing the opening of a secondary battery case, wherein the cap assembly comprises: Cap plate with a through hole formed therein; A lower insulating plate disposed at the lower part of the above-mentioned cap plate and having a protrusion formed at its inner end; and A cap assembly comprising: an electrode terminal disposed on the upper part of the cap plate, inserted into the through hole, and having a first fitting groove formed on its outer surface into which the protrusion is fitted.

18. In Paragraph 17, The above electrode terminal comprises a terminal body formed on the upper part of the cap plate and a terminal projection that protrudes from the lower surface of the terminal body, is inserted into the through hole, has an insertion groove formed upwardly in the center into which a current collecting projection is inserted, and has a first fitting groove formed on its outer surface.

19. In Paragraph 18, A cap assembly comprising an upper insulating plate formed on the upper part of the cap plate, wherein a sealing gasket is interposed between the upper insulating plate and the terminal projection.

20. In Paragraph 19, A cap assembly formed such that the terminal projection-side end of the sealing gasket extends from the lower surface of the terminal body to the projection.

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