Cylindrical secondary battery, and battery pack and vehicle including the same

Abstract

According to the present invention, a cylindrical secondary battery with a simple electrical connection structure can be obtained by providing a through terminal so that the positive terminal and the negative terminal are located in the same direction. In addition, the cylindrical secondary battery of the present invention can increase capacity and improve vibration characteristics by providing a thin insulating coating layer on the inner wall of the battery can.

Description

Technology Field

[0001] The present invention relates to a cylindrical secondary battery, a battery pack including the same, and an automobile.

[0002] More specifically, the invention relates to a cylindrical secondary battery having a structure in which both a positive terminal and a negative terminal are disposed on one side of the cylindrical secondary battery, wherein an insulating coating layer capable of efficiently insulating the electrode assembly and the current collector plate is formed on the battery can, and to a battery pack including the same and an automobile. Background Technology

[0003] When manufacturing a battery pack using cylindrical secondary batteries, typically

[0004] Multiple cylindrical secondary batteries are arranged upright within a housing, and the top and bottom of the cylindrical secondary batteries are utilized as the positive and negative terminals, respectively, to electrically connect the multiple cylindrical secondary batteries to one another.

[0005] That is, in conventional cylindrical secondary batteries, the bottom surface of the battery can is generally used as the negative terminal, and the top cap covering the top opening of the battery can is generally used as the positive terminal.

[0006] However, when the positive and negative terminals of a cylindrical secondary battery are located on opposite sides, electrical connection components, such as busbars for electrically connecting multiple cylindrical secondary batteries, must be applied to both the upper and lower parts of the battery. Furthermore, as a result, components for insulation and for ensuring waterproofing or sealing must be applied individually to the upper and lower parts of the battery pack, leading to an increase in the number of components and structural complexity.

[0007] To resolve this complex structure, the applicant proposed a cylindrical secondary battery structure in which the positive terminal and the negative terminal are applied in the same direction.

[0008] Figure 1 is a schematic diagram showing a simplified upper structure of such a cylindrical secondary battery.

[0009] However, in FIG. 1, a cap-shaped insulator (3) is applied to insulate the electrode assembly (1) or the current collector plate (not shown) coupled thereto from the battery can (2). That is, the insulator (3) is in a form that completely surrounds the current collector plate and the electrode assembly (1) to insulate the inner wall of the battery can (2) and the electrode assembly (1), and the insulator (3) is provided with side portions (3a) interposed between the current collector plate / electrode assembly and the inner wall of the battery can on both sides. In this form, the volume of the electrode assembly (1) is reduced by the thickness of the side portions (3a), so the capacity is reduced. In addition, since the electrode assembly (1) and the battery can (2) are separated by the thickness of the side portions (3a), there is a problem that the vibration characteristics of the secondary battery are degraded.

[0011] Therefore, it is desirable to develop a cylindrical secondary battery having an insulating structure capable of preventing such capacity reduction or degradation of vibration characteristics. Prior art literature

[0012] Republic of Korea Published Patent Application No. 10-2020-0041625 The problem to be solved

[0013] The present invention, devised in consideration of the aforementioned problems, aims to provide a cylindrical secondary battery having an insulating structure capable of preventing capacity reduction and degradation of vibration characteristics, wherein the positive terminal and the negative terminal are applied in the same direction. means of solving the problem

[0014] A cylindrical secondary battery according to one embodiment of the present invention for solving the above-described problem comprises: an electrode assembly having a first electrode tab and a second electrode tab; a battery can that accommodates the electrode assembly and is electrically connected to the electrode assembly; a through terminal that penetrates one side of the battery can and is electrically connected to the electrode assembly; a first current collector plate having a first side coupled to the first electrode tab and a second side coupled to the through terminal; an insulator interposed between the first current collector plate and the battery can; and a cap plate that covers an opening of the battery can; wherein an insulating coating layer is formed along the inner circumferential surface of the side wall of the battery can facing the side of the first electrode tab and the side of the first current collector plate.

[0015] The above-mentioned through-terminal is electrically connected to the first electrode tab having a first polarity, and the battery can can be electrically connected to the second electrode tab having a second polarity different from the first polarity.

[0016] As an example, the through terminal may be located at the center of one side of the battery can located on the opposite side of the opening.

[0017] Specifically, the through terminal may include a terminal exposure portion extending to the outside of the battery can; and a terminal insertion portion penetrating the upper surface of the battery can.

[0018] The above through terminal can be riveted onto the inner surface of the battery can.

[0019] The central region of the terminal insertion part can be combined with the first current collector plate.

[0020] The above-mentioned through terminal can pass through the insulator and be coupled with the first current collector plate.

[0021] As an example, the insulator may be formed in a flat plate shape having a through hole through which the through terminal passes.

[0022] The insulating coating layer may be formed to extend to the inner surface of the side wall of the battery can and / or the inner surface of the top plate of the battery can, exceeding the area of ​​the inner surface of the side wall of the battery can facing the side of the first electrode tab and the side of the first current collector plate.

[0023] As a specific example, the insulating coating layer may include one or more selected from the group consisting of epoxy, ceramic, and Teflon.

[0024] The above-described cylindrical secondary battery may further include an insulating gasket interposed between the battery can and the through terminal to insulate the through terminal and the battery can.

[0025] Specifically, the insulating gasket may include a gasket exposure portion extending to the outside of the battery can; and a gasket insertion portion penetrating the upper surface of the battery can.

[0026] The above cap plate may be provided with a venting portion configured to rupture and release gas when the internal pressure of the battery can increases above a certain level.

[0027] A battery pack according to one embodiment of the present invention may include a plurality of cylindrical secondary batteries and a pack housing that accommodates the plurality of cylindrical secondary batteries.

[0028] An automobile of one embodiment of the present invention may include the battery pack. Effects of the invention

[0029] According to the present invention, a cylindrical secondary battery with a simple electrical connection structure can be obtained in which the positive terminal and the negative terminal are located in the same direction.

[0030] In addition, according to the present invention, by providing a thin insulating coating layer, it is possible to increase capacity and improve vibration characteristics.

[0031] However, the effects obtainable through the present invention are not limited to those described above, and other unmentioned technical effects will be clearly understood by those skilled in the art from the description of the invention below. Brief explanation of the drawing

[0032] The following drawings attached to this specification illustrate preferred 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. FIG. 1 is a schematic diagram showing a simplified upper structure of a cylindrical secondary battery proposed by the applicant. FIG. 2 is a drawing showing the external appearance of a cylindrical secondary battery according to one embodiment of the present invention. FIG. 3 is a cross-sectional view showing the internal structure of a cylindrical secondary battery according to one embodiment of the present invention. FIG. 4 is a partial cross-sectional view showing the upper structure of a cylindrical secondary battery according to one embodiment of the present invention. FIG. 5 is a partial cross-sectional view showing the formation location of the insulating coating layer, which is a key part of the present invention. FIGS. 6 and FIGS. 7 are partial cross-sectional views showing other examples of the formation location of the insulating coating layer, which is a key part of the present invention. FIG. 8 is a drawing showing the lower surface of a cylindrical secondary battery according to one embodiment of the present invention. FIG. 9 is a drawing showing a battery pack according to one embodiment of the present invention. FIG. 10 is a drawing showing an automobile according to one embodiment of the present invention. Specific details for implementing the invention

[0033] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the attached drawings. Prior to this, terms and words used in this specification and claims should not be interpreted as being limited to their ordinary or dictionary meanings, but should be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. Accordingly, the embodiments described in this specification and the configurations illustrated in the drawings are merely some of the most preferred embodiments of the present invention and do not represent all of the technical spirit of the present invention; therefore, it should be understood that various equivalents and modifications capable of replacing them may exist at the time of filing this application.

[0035] Referring to FIGS. 2 to 4, a cylindrical secondary battery (100) according to one embodiment of the present invention comprises an electrode assembly (10), a battery can (20), a cap plate (30), a through terminal (40), a first current collector plate (60), and an insulator (70). In addition to the components described above, the cylindrical secondary battery (100) may further comprise an insulating gasket (50) and / or a second current collector plate (80).

[0036] The electrode assembly (10) comprises a first electrode having a first polarity, a second electrode having a second polarity, and a separator interposed between the first electrode and the second electrode. The first electrode is a positive or negative electrode, and the second electrode corresponds to an electrode having a polarity opposite to that of the first electrode. The electrode assembly (10) may have, for example, a jelly-roll shape. That is, the electrode assembly (10) may be manufactured by winding a laminate formed by sequentially stacking the first electrode, the separator, and the second electrode at least once, based on a winding center (C). In this case, an additional separator may be provided on the outer surface of the electrode assembly (10) to provide insulation from the battery can (20).

[0037] The first electrode comprises a first electrode active material applied to one or both sides of a first electrode current collector. At one end of the first electrode current collector in the width direction (direction parallel to the Z-axis), there exists a blank area where the first electrode active material is not applied. The blank area functions as a first electrode tab (11). The first electrode tab (11) is provided on the upper side in the height direction (direction parallel to the Z-axis) of an electrode assembly (10) housed in a battery can (20).

[0038] The second electrode comprises a second electrode active material applied to one or both sides of the second electrode current collector. At the other end of the second electrode current collector in the width direction (a direction parallel to the Z-axis), there exists a blank area where the second electrode active material is not applied. The blank area functions as a second electrode tab (12). The second electrode tab (12) is provided in the lower height direction of the electrode assembly (10) housed in the battery can (20).

[0039] In the present invention, the positive active material coated on the positive plate and the negative active material coated on the negative plate may be used without limitation as long as they are active materials known in the art.

[0040] In one example, the positive active material is the general chemical formula A[A x M y ]O 2+z It may include an alkali metal compound represented by (A includes at least one element among Li, Na and K; M includes at least one element selected from Ni, Co, Mn, Ca, Mg, Al, Ti, Si, Fe, Mo, V, Zr, Zn, Cu, Al, Mo, Sc, Zr, Ru, and Cr; x ≥ 0, 1 ≤ x+y ≤ 2, 0.1 ≤ z ≤ 2; the stoichiometric coefficients of the components included in x, y, z and M are selected so that the compound maintains electrical neutrality).

[0041] Preferably, the positive active material may include primary particles and / or secondary particles formed by the aggregation of primary particles.

[0042] In one example, the negative electrode active material may be a carbon material, lithium metal or lithium metal compound, silicon or silicon compound, tin or tin compound, etc. Metal oxides such as TiO2 and SnO2 with a potential of less than 2V may also be used as negative electrode active materials. As for the carbon material, low-crystallinity carbon, high-crystallinity carbon, etc. may all be used.

[0043] The separator may be a porous polymer film, such as a polyolefin-based polymer like ethylene homopolymer, propylene homopolymer, ethylene / butene copolymer, ethylene / hexene copolymer, or ethylene / methacrylate copolymer, used alone or in a laminate thereof. As another example, the separator may be a conventional porous nonwoven fabric, such as a nonwoven fabric made of high-melting-point glass fibers or polyethylene terephthalate fibers.

[0044] At least one surface of the separation membrane may include a coating layer of inorganic particles.

[0045] In addition, it is possible for the membrane itself to consist of a coating layer of inorganic particles. The particles constituting the coating layer may have a structure bonded with a binder such that interstitial volume exists between adjacent particles.

[0046] The electrolyte is A + B -- It may be a salt having a structure like that. Here, A + is Li + , Na + , K + It includes alkali metal cations such as or ions composed of combinations thereof. And B -- is F -- , Cl -- , Br -- , I -- , NO3-- , N(CN)2 -- , BF4 -- , ClO4 -- , AlO4 -- , AlCl4 -- , PF6 -- , SbF6 -- , AsF6 -- , BF2C2O4 -- , BC4O8 -- , (CF3)2PF4 -- , (CF3)3PF3 - , (CF3)4PF2 -- , (CF3)5PF -- , (CF3)6P -- , CF3SO3 -- , C4F9SO3 -- , CF3CF2SO3 -- , (CF3SO2)2N -- , (FSO2)2N -- , CF3CF2(CF3)2CO -- , (CF3SO2)2CH -- , (SF5)3C -- , (CF3SO2)3C -- , CF3(CF2)7SO3 -- , CF3CO2 -- , CH3CO2 - ,SCN-- and (CF3CF2SO2)2N -- It includes one or more anions selected from the group consisting of

[0047] The electrolyte can also be dissolved in an organic solvent for use.

[0049] Referring to FIGS. 2 to 4, the battery can (20) is a roughly cylindrical receptacle with an opening formed at the bottom, and is made of, for example, a conductive metal material. The bottom portion of the battery can (20) having the opening is referred to as the open end. The side (outer surface) and the top surface of the battery can (20) may be formed integrally. The top surface (a surface parallel to the XY plane) of the battery can (20) has a roughly flat shape. The top surface located opposite the opening (or open end) is referred to as the closed end. The battery can (20) accommodates an electrode assembly (10) through the opening formed at the bottom, and also accommodates an electrolyte.

[0050] The battery can (20) is electrically connected to the electrode assembly (10). The battery can (20) is electrically connected, for example, to the second electrode tab (12) of the electrode assembly (10).

[0051] In this case, the battery can (20) has the same polarity as the second electrode tab (12).

[0052] Referring to FIGS. 3 and FIGS. 8, the battery can (20) may have a beading portion (21) and a crimping portion (22) formed at the bottom. The beading portion (21) has a shape in which the outer circumference of the battery can (20) is pressed in to a predetermined depth. The beading portion (21) is formed at the bottom of the electrode assembly (10). The beading portion (21) prevents the electrode assembly (10), which may have a size approximately corresponding to the width of the battery can (20), from coming out through the opening formed at the bottom of the battery can (20), and can function as a support portion on which the cap plate (30) is seated.

[0053] The above-mentioned crimping portion (22) is formed at the lower part of the beading portion (21). The crimping portion (22) has an extended and bent shape to wrap around the outer surface and lower surface of the cap plate (30) positioned below the beading portion (21).

[0054] However, the present invention is such that the battery can (20) has such a beading portion (21) and / or a crimping portion (22).

[0055] The case in which it is not provided is not excluded. In the present invention, if the battery can (20) does not have a beading portion (21) and / or a crimping portion (22), the fixing of the electrode assembly (10) and / or the fixing of the cap plate (30) and / or the sealing of the battery can (20) can be realized, for example, through the additional application of a part that can function as a stopper for the electrode assembly (10) and / or the additional application of a structure on which the cap plate (30) can be seated and / or welding between the battery can (20) and the cap plate (30).

[0056] Referring to FIGS. 3 and FIGS. 8, the cap plate (30) may be made of, for example, a metal material to ensure rigidity. The cap plate (30) covers an opening (or open end) formed at the bottom of the battery can (20). That is, the cap plate (30) forms the lower surface of the cylindrical secondary battery (100). In the cylindrical secondary battery (100) of the present invention, the cap plate (30) does not have polarity even if it is made of a conductive metal material. Not having polarity may mean that the cap plate (30) is electrically insulated from the battery can (20) and the through terminal (40). Therefore, the cap plate (30) does not function as a positive terminal or a negative terminal. Accordingly, the cap plate (30) does not need to be electrically connected to the electrode assembly (10) and the battery can (20), and its material does not necessarily have to be a conductive metal.

[0057] When the battery can (20) of the present invention is provided with a beading portion (21), the cap plate (30) may be seated on the beading portion (21) formed on the battery can (20). Additionally, when the battery can (20) of the present invention is provided with a crimping portion (22), the cap plate (30) is fixed by the crimping portion (22). A sealing gasket (90) may be interposed between the cap plate (30) and the crimping portion (22) of the battery can (20) to ensure airtightness of the battery can (20).

[0058] Meanwhile, as previously explained, the battery can (20) of the present invention may not have a beading portion (21) and / or a crimping portion (22), and in this case, the airtight gasket (90) may be interposed between a fixing structure provided on the opening side of the battery can (20) and a cap plate (30) to ensure airtightness of the battery can (20).

[0059] Referring to FIG. 8, the cap plate (30) may further be provided with a venting portion (31) formed to prevent the internal pressure from increasing beyond a preset value due to gas generated inside the battery can (20). The venting portion (31) corresponds to an area of ​​the cap plate (30) that has a thinner thickness compared to the surrounding area. The venting portion (31) is structurally weak compared to the surrounding area. Therefore, if an abnormality occurs in the cylindrical secondary battery (100) and the internal pressure of the battery can (20) increases above a certain level, the venting portion (31) breaks, and the gas generated inside the battery can (20) is discharged. The venting portion (31) can be formed, for example, by notching on one or both sides of the cap plate (30) to partially reduce the thickness of the battery can (20).

[0061] A cylindrical secondary battery (100) according to one embodiment of the present invention has a structure in which both a positive terminal and a negative terminal exist at the top, and as a result, the upper structure is more complex than the lower structure. Accordingly, a venting portion (31) may be formed on a cap plate (30) forming the lower surface of the cylindrical secondary battery (100) to facilitate the smooth discharge of gas generated inside the battery can (20). As shown in FIG. 8, it is preferable that the lower portion of the cap plate (30) be located higher than the lower portion of the battery can (20). In this case, even if the lower portion of the battery can (20) touches the ground or the bottom surface of a housing for a module or pack configuration, the cap plate (30) does not touch the ground or the bottom surface of the housing for a module or pack configuration. Therefore, the phenomenon in which the pressure required for the rupture of the venting part (31) differs from the design value due to the weight of the cylindrical secondary battery (100) can be prevented, and accordingly, the smooth rupture of the venting part (31) can be ensured.

[0063] Referring to FIGS. 2 to 4, the through terminal (40) is made of a conductive metal material and passes through the upper surface of the battery can (20), that is, the surface located opposite the opening of the battery can (20) (a surface parallel to the XY plane). The through terminal (40) is electrically connected, for example, to the first electrode tab (11) of the electrode assembly (10). In this case, the through terminal (40) has a first polarity. Thus, the through terminal (40) can function as a first electrode terminal in the cylindrical secondary battery (100) of the present invention. When the through terminal (40) has such a first polarity, the through terminal (40) is electrically insulated from the battery can (20) having a second polarity. Electrical insulation between the through terminal (40) and the battery can (20) can be realized in various ways. For example, insulation can be achieved by interposing an insulating gasket (50) between the above-mentioned through terminal (40) and the battery can (20).

[0064] The above-mentioned through terminal (40) includes a terminal exposure portion (41) and a terminal insertion portion (42). The terminal exposure portion (41) is exposed to the outside of the battery can (20). The terminal exposure portion (41) may be located approximately in the center of the upper surface of the battery can (20). The maximum width of the terminal exposure portion (41) may be formed to be larger than the maximum width of the hole formed in the battery can (20) due to the penetration of the through terminal (40). The terminal insertion portion (42) may penetrate approximately in the center of the upper surface of the battery can (20) and be electrically connected to the first electrode tab (11). The perimeter area of ​​the terminal insertion portion (42) may be riveted onto the inner surface of the battery can (20). That is, the perimeter area of ​​the terminal insertion part (42) may have a curved shape toward the inner surface of the battery can (20), and thus the maximum width of the end of the terminal insertion part (42) may be formed to be larger than the maximum width of the hole in the battery can (20) formed by the penetration of the terminal insertion part (42).

[0065] Meanwhile, the cylindrical secondary battery (100) of the present invention is provided with a first current collector plate (60), and the first surface of the first current collector plate (60) is coupled to the first electrode tab (11) and the second surface is coupled to the through terminal (40). In this case, the central area of ​​the terminal insertion part (42) of the through terminal (40) can be coupled to the second surface (upper surface) of the first current collector plate (60). The central area of ​​the terminal insertion part (42) may have, for example, a roughly cylindrical shape. The diameter of the bottom surface of the central area of ​​the terminal insertion part (42) may be set to approximately 6.2 mm.

[0066] The connection between the bottom surface of the central area of ​​the terminal insertion part (42) and the first current collector plate (60) can be achieved, for example, by laser welding or ultrasonic welding.

[0067] The above laser welding can be performed by irradiating a laser through a hole formed at the winding center (C) of the electrode assembly (10) to form a laser welding line on one side of the first collector plate (60).

[0068] In one embodiment of the present invention, the upper surface of the battery can (20) and the through terminal (40) exposed to the outside of the battery can (20) have opposite polarities and face in the same direction. Additionally, a step may be formed between the through terminal (40) and the upper surface of the battery can (20). Specifically, if the entire upper surface of the battery can (20) has a flat shape or has a shape protruding upward from its center, the terminal exposure portion (41) of the through terminal (40) may protrude further upward than the upper surface of the battery can (20). Conversely, if the upper surface of the battery can (20) has a shape that is concavely indented downward from its center, that is, in the direction toward the electrode assembly (10), the upper surface of the battery can (20) may protrude further upward than the terminal exposure portion (41) of the electrode terminal (40).

[0069] Meanwhile, in the case where the upper surface of the battery can (20) has a shape that is concavely indented downward from its center, that is, in the direction toward the electrode assembly (10), the upper surface of the battery can (20) and the upper surface of the terminal exposure portion (41) may form the same plane depending on the depth of the indentation and the thickness of the terminal exposure portion (41) of the electrode terminal (40). In this case, a step may not be formed between the upper surface of the battery can (20) and the terminal exposure portion (41).

[0070] The insulating gasket (50) is interposed between the battery can (20) and the through terminal (40) to prevent the battery can (20) and the through terminal (40), which have opposite polarities, from coming into contact with each other. As a result, the upper surface of the battery can (20), which has a roughly flat shape, can function as a second electrode terminal of the cylindrical secondary battery (100).

[0071] The insulating gasket (50) includes a gasket exposure portion (51) and a gasket insertion portion (52). The gasket exposure portion (51) is interposed between the terminal exposure portion (41) of the through terminal (40) and the battery can (20). The gasket insertion portion (52) is interposed between the terminal insertion portion (42) of the through terminal (40) and the battery can (20). The gasket insertion portion (52) can be deformed together with the terminal insertion portion (42) during riveting and adhere to the inner surface of the battery can (20). The insulating gasket (50) may be made of, for example, an insulating resin material.

[0072] In the case where the insulating gasket (50) is made of a resin material, the insulating gasket (50) can be joined to the battery can (20) and the through terminal (40) by heat fusion.

[0073] In this case, airtightness at the joint interface between the insulating gasket (50) and the through terminal (40) and at the joint interface between the insulating gasket (50) and the battery can (20) can be enhanced.

[0074] The entire remaining area of ​​the upper surface of the battery can (20), excluding the area occupied by the through terminal (40) and the insulating gasket (50), corresponds to a second electrode terminal (20a) having opposite polarity to the through terminal (40).

[0075] The cylindrical side wall of the battery can (20) may be formed as one piece with the second electrode terminal (20a) so that there is no discontinuous portion between it and the second electrode terminal (20a). The connection from the side wall of the battery can (20) to the second electrode terminal (20a) may be a smooth curve. However, the present invention is not limited thereto, and the connection portion may include at least one corner having a predetermined angle.

[0076] Referring to FIGS. 3 and 4, the first current collector plate (60) is coupled to the upper part of the electrode assembly (10). The first current collector plate (60) is made of a conductive metal material and is connected to the first electrode tab (11). Although not shown in the drawings, the first current collector plate (60) may have a plurality of irregularities formed radially on its lower surface. When the irregularities are formed, the first current collector plate (60) can be pressed to press the irregularities into the first electrode tab (11).

[0077] Although not illustrated, the first current collector plate (60) may be coupled to a coupling surface formed by bending the end of the first electrode tab (11) in a direction parallel to the first current collector plate (60). The bending direction of the first electrode tab (11) may, for example, be a direction toward the winding center (C) of the electrode assembly (10). When the first electrode tab (11) has such a bent shape, the space occupied by the first electrode tab (11) is reduced, which can lead to an improvement in energy density. Additionally, due to the increase in the coupling area between the first electrode tab (11) and the first current collector plate (60), an improvement in coupling strength and a reduction in resistance may be achieved.

[0078] Referring to FIGS. 3 and 4, an insulator (70) is provided between the first current collector plate (60) coupled to the upper part of the electrode assembly (10) and the inner surface of the battery can (20). The insulator (70) prevents contact between the first current collector plate (60) and the battery can (20).

[0079] Meanwhile, as shown in FIG. 1, if the insulator is formed in a cap shape having a side portion (3a) interposed between the upper end of the outer surface of the electrode assembly and the inner surface of the battery can, contact between the first electrode tab and the battery can can be prevented. However, in this case, the capacity may be reduced and the vibration characteristics may be degraded due to the side thickness of the insulator caused by the side portion.

[0080] Accordingly, in the present invention, the insulator is formed in a flat shape, for example, without side portions, to prevent only contact between the first current collector plate (60) and the battery can (20).

[0081] The first current collector plate (60) may be a plate that extends completely across the upper outer surface of the electrode assembly (10). However, the present invention is not limited thereto, and the first current collector plate (60) may be formed to extend only partially across the upper outer surface of the electrode assembly (10).

[0082] In a cylindrical secondary battery (100) according to one embodiment of the present invention, the terminal insertion portion (42) of the through terminal (40) may pass through an insulator (70) and be coupled to a first current collector plate (6011). The insulator (70) may have an opening adjacent to the winding center (C). Through the opening, the terminal insertion portion (42) of the through terminal (40) may come into direct contact with the first current collector plate (60).

[0083] In the present invention, in order to increase capacity and improve vibration characteristics, an insulating coating layer (23) is formed along the inner circumferential surface of the side wall of the battery can (20) facing the side of the first electrode tab (11) and the side of the first current collector plate (60). That is, as shown in FIG. 1, the side of the thick insulator is not positioned to face the battery can, the side of the first electrode tab, and the side of the first current collector plate, but rather a thin insulating coating layer (23) is formed on the battery can to replace the insulating function of the cap-shaped insulator. For example, the thickness of the side of the insulator (3a) in FIG. 1 is 0.3t (0.3mm), and the combined thickness of the side of both sides is 0.6mm. That is, the width of the electrode assembly within the cylindrical secondary battery (100) is reduced by this thickness, thereby reducing the battery capacity. In addition, since the thick side portion (3a) is interposed between the electrode assembly and the battery can, vibration characteristics are also deteriorated, such as increasing vibration when vibration is applied.

[0084] On the other hand, as shown in FIGS. 3 and 4, when an insulating coating layer (23) is formed in the inner circumferential area of ​​the side wall of the battery can (20) facing the side of the first electrode tab (11) and the side of the first current collector plate (60), the thickness of the insulating coating layer (23) can be determined in the range of approximately 3 to 100 μm. In this way, since the insulating coating layer (23) has a much thinner thickness compared to the insulator of FIG. 1, the width of the electrode assembly (10) can be increased accordingly, thereby increasing the battery capacity. In addition, the vibration characteristics of the cylindrical secondary battery (100) are further improved.

[0085] The insulating coating layer (23) may include one or more materials selected from the group consisting of epoxy, ceramic, and Teflon, but is not limited thereto. For example, the insulating coating layer (23) may be formed using other materials that can be used for electrical insulation with other metal bodies within a metal battery can.

[0086] This insulating coating layer (23) can be applied to the inner wall of the battery can, for example, by spraying, and other suitable coating methods can also be applied.

[0087] FIG. 5 is a partial cross-sectional view showing the formation location of an insulating coating layer, which is a key part of the present invention, and FIG. 6 and FIG. 7 are partial cross-sectional views showing other examples of the formation location of an insulating coating layer, which is a key part of the present invention.

[0088] In FIGS. 5 to 7, the insulator, the first current collector plate, and the electrode assembly are omitted to clearly show the location where the insulating coating layer is formed.

[0089] Referring to FIG. 5, the insulating coating layer (23) is basically formed in an area facing the side of the first electrode tab (11) and the side of the first current collector plate (60). That is, if the insulator (70) insulates the upper part of the first current collector plate (60) and the battery can (20), the insulating coating layer (23) insulates the side of the first current collector plate (60) and the battery can (20). Therefore, the upper area of ​​the insulating coating layer (23) must be an area that includes at least the side of the first current collector plate (60). To ensure more reliable insulation between the first current collector plate (60) and the battery can (20), the insulating coating layer (23) can be extended beyond the area facing the first current collector plate (60) as shown in FIG. 6.

[0090] Additionally, the insulating coating layer (23) is coated along the inner surface of the battery can sidewall facing the side of the first electrode tab (11) in order to insulate the side of the first electrode tab (11) (the outer periphery of the first electrode tab) from the battery can (20). Accordingly, the lower region of the insulating coating layer (23) must be an area that includes at least the side of the first electrode tab (11). To ensure more reliable insulation between the first electrode tab (11) and the battery can (20), it is preferable that the lower region of the insulating coating layer (23) be formed to extend beyond the area facing the first electrode tab (11) (see FIG. 4 and FIG. 5).

[0091] Meanwhile, in order to ensure more secure insulation between the first collector plate (60) and the battery can (20), it is also possible to form the insulating coating layer (23) by extending it to the inner surface of the top plate of the battery can, which extends beyond the inner circumferential area of ​​the side wall of the battery can (20), as shown in FIG. 7. However, in this case, since welding must be performed on the rivet joint of the through terminal (40), it is necessary to form the insulating coating layer only on the inner surface of the battery can (20), excluding this rivet joint.

[0092] The height of the insulating coating layer (23) can be determined according to the size of the battery, the current collector plate, and the height of the electrode tab. For example, as one embodiment, the height of the insulating coating layer (23) can be determined within a range of 5 mm or less. However, in order to obtain an insulating effect, it is preferable that the height of the insulating coating layer (23) be 2 mm or more.

[0093] As shown in FIGS. 5 to 7, when an insulating coating layer (23) is applied in advance at a predetermined location on the inner wall of the battery can (20), the above-described electrode assembly (10), first current collector plate (60), through terminal (40), etc. are combined with the battery can (20), the cylindrical secondary battery (100) of the present invention can be easily manufactured.

[0094] Referring to FIGS. 3 and 8, a second current collector plate (80) is coupled to the lower part of the electrode assembly (10). The second current collector plate (80) is made of a conductive metal material and is connected to the second electrode tab (12). Additionally, the second current collector plate (80) is electrically connected to the battery can (20). The second current collector plate (80) may be fixed by being interposed between the inner surface of the battery can (20) and the sealing gasket (90), as shown in FIG. 8. Alternatively, the second current collector plate (80) may be welded to the inner wall surface of the battery can (20).

[0095] Although not illustrated, the second current collector plate (80) may be coupled to a coupling surface formed by bending the end of the second electrode tab (12) in a direction parallel to the second current collector plate (80). The bending direction of the second electrode tab (12) may, for example, be a direction toward the winding center (C) of the electrode assembly (10). When the second electrode tab (12) has such a bent shape, the space occupied by the second electrode tab (12) is reduced, which can lead to an improvement in energy density. Additionally, the increase in the coupling area between the second electrode tab (12) and the second current collector plate (80) can lead to improved coupling strength and reduced resistance.

[0096] Referring to FIGS. 3 and 4, a cylindrical secondary battery (100) according to one embodiment of the present invention is provided with a through terminal (40) having a first polarity and a second electrode terminal (20a) having a second polarity that is electrically insulated from the through terminal (40) on one side in the longitudinal direction (a direction parallel to the Z-axis). That is, in the cylindrical secondary battery (100) according to one embodiment of the present invention, since a pair of electrode terminals (30, 20a) are located in the same direction, when electrically connecting a plurality of cylindrical secondary batteries (100), it is possible to place electrical connection components, such as a busbar, only on one side of the cylindrical secondary battery (100). This can lead to simplification of the battery pack structure and improvement of energy density.

[0097] In addition, the cylindrical secondary battery (100) has a structure in which one side of a battery can (20) having a roughly flat shape can be used as a second electrode terminal (20a), thereby securing a sufficient bonding area for bonding electrical connection components, such as a bus bar, to the second electrode terminal (20a). Accordingly, the cylindrical secondary battery (100) can secure sufficient bonding strength between the electrical connection component and the second electrode terminal (20a), and can reduce the resistance at the bonding area to a desirable level.

[0098] In addition, the cylindrical secondary battery (100) of the present invention has the effect of being able to increase the battery capacity and prevent the deterioration of vibration characteristics by forming a thin insulating coating layer (23) on the inner wall of the battery can, thereby increasing the width of the electrode assembly (10) facing it.

[0099] Preferably, the cylindrical battery cell may be a cylindrical battery cell in which the ratio of the form factor (defined as the ratio of the diameter of the cylindrical battery cell to the height, i.e., the ratio of the diameter (Φ) to the height (H)) is approximately greater than 0.4.

[0100] Here, the form factor refers to a value representing the diameter and height of a cylindrical battery cell. A cylindrical battery cell according to one embodiment of the present invention may be, for example, a 46110 cell, a 48750 cell, a 48110 cell, a 48800 cell, or a 46800 cell. In the numerical value representing the form factor, the first two digits represent the diameter of the cell, the next two digits represent the height of the cell, and the last digit 0 represents that the cross-section of the cell is circular.

[0101] A battery cell according to one embodiment of the present invention may be a cylindrical battery cell having a roughly cylindrical shape, with a diameter of approximately 46 mm, a height of approximately 110 mm, and a form factor ratio of approximately 0.418.

[0102] A battery cell according to another embodiment may be a cylindrical battery cell having a roughly cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 75 mm, and a form factor ratio of approximately 0.640.

[0103] A battery cell according to another embodiment may be a cylindrical battery cell having a roughly cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 110 mm, and a form factor ratio of approximately 0.418.

[0104] A battery cell according to another embodiment may be a cylindrical battery cell having a roughly cylindrical shape, with a diameter of approximately 48 mm, a height of approximately 80 mm, and a form factor ratio of approximately 0.600.

[0105] A battery cell according to another embodiment may be a cylindrical battery cell having a diameter of approximately 46 mm, a height of approximately 80 mm, and a form factor ratio of approximately 0.575.

[0106] Conventionally, battery cells with a form factor ratio of approximately 0.4 or less were used. That is, conventionally, for example, 18650 cells, 21700 cells, etc. were used. In the case of the 18650 cell, its diameter is approximately 18 mm, its height is approximately 65 mm, and its form factor ratio is approximately 0.277.

[0107] For the 21700 cell, its diameter is approximately 21 mm, its height is approximately 70 mm, and its form factor ratio is approximately 0.300.

[0108] Referring to FIG. 9, a battery pack (300) according to one embodiment of the present invention comprises a secondary battery assembly in which a plurality of cylindrical secondary batteries (100) according to one embodiment of the present invention as described above are electrically connected, and a pack housing (200) that accommodates the same. In the drawings of the present invention, components such as a busbar for electrical connection, a cooling unit, and a power terminal are omitted for convenience of drawing.

[0109] Referring to FIG. 10, a vehicle (500) according to one embodiment of the present invention may be, for example, an electric vehicle, a hybrid vehicle, or a plug-in hybrid vehicle, and includes a battery pack (300) according to one embodiment of the present invention. The vehicle (500) includes four-wheeled vehicles and two-wheeled vehicles. The vehicle (500) operates by receiving power from the battery pack (300) according to one embodiment of the present invention.

[0111] Although the present invention has been described above by limited embodiments and drawings, the present invention is not limited thereto, and it is obvious that various modifications and variations are possible within the scope of the technical spirit of the present invention and the equivalent scope of the claims described below by those skilled in the art to which the present invention belongs. Explanation of the symbols

[0112] 10: Electrode assembly C: Winding center 11: First electrode tab 12: Second electrode tab 20: Battery can 21: Bidding Department 22: Creaming Department 23: Insulating coating layer 30: Cap plate 31: Venting Department 40: Through-hole terminal 41: Terminal section 42: Insert 50: Insulation gasket 60: First ceremonial tablet 70: Insulator 80: Second tribunal 90: Airtight gasket 100: Cylindrical secondary battery 200: Pack Housing 300: Battery pack 500: Car

Claims

Claim 1 A cylindrical secondary battery comprising: an electrode assembly having a first electrode tab and a second electrode tab; a battery can that accommodates the electrode assembly and is electrically connected to the electrode assembly, the battery can having a first end surface with an opening formed therein and a second end surface located opposite to the first end surface; a through terminal that penetrates the second end surface of the battery can and is electrically connected to the electrode assembly; a first current collector plate having a first surface coupled to the first electrode tab and a second surface coupled to the through terminal; and a second current collector plate coupled to the second electrode tab, wherein the battery can has a top plate on the side of the second end surface and an insulating coating layer is formed on the inner surface of the top plate facing the second surface of the first current collector plate. Claim 2 A cylindrical secondary battery according to claim 1, characterized in that the second current collector is coupled to a coupling surface formed by bending the end of the second electrode tab in a direction parallel to the second current collector. Claim 3 A cylindrical secondary battery according to claim 2, wherein the electrode assembly is in a shape in which a laminate of a first electrode, a separator, and a second electrode is wound with respect to a winding center, and the direction in which the end of the second electrode tab is bent is a direction toward the winding center of the electrode assembly. Claim 4 A cylindrical secondary battery according to claim 1, further comprising a cap plate covering the opening of the battery can. Claim 5 A cylindrical secondary battery according to claim 4, characterized in that a sealing gasket is interposed between the cap plate and the battery can. Claim 6 A cylindrical secondary battery according to claim 5, characterized in that the second current collector plate is interposed and fixed between the inner surface of the battery can and the airtight gasket. Claim 7 A cylindrical secondary battery according to claim 6, wherein both ends of the second current collector plate are bent downward, and the downwardly bent ends are fixed between the inner surface of the battery can and the airtight gasket. Claim 8 A cylindrical secondary battery according to claim 1, wherein the through terminal is riveted onto the inner surface of the battery can. Claim 9 A cylindrical secondary battery according to claim 8, wherein the insulating coating layer is formed on the inner surface of the top plate, excluding the portion where the through terminal is riveted to the battery can. Claim 10 A cylindrical secondary battery according to claim 1, characterized in that the first cross-section of the battery can has an opening to form an open end, and the second cross-section is formed as a cylindrical shape with a bottom to form a closed end. Claim 11 A cylindrical secondary battery according to claim 1, further comprising an insulator interposed between the first current collector plate and the battery can. Claim 12 A cylindrical secondary battery according to claim 11, wherein the through terminal passes through the insulator and is coupled to the first current collector plate. Claim 13 A cylindrical secondary battery according to claim 12, wherein the insulator is formed in a flat plate shape having a through hole through which the through terminal passes. Claim 14 In claim 1, the insulating coating layer on the inner surface of the upper plate is extended and formed along the inner circumferential surface of the side wall of the battery can facing the side of the first current collector plate. Cylindrical secondary battery characterized by the following. Claim 15 A cylindrical secondary battery according to claim 1, wherein the insulating coating layer is formed by extending along the inner surface of the side wall of the battery can facing the side of the first electrode tab and the side of the first current collector plate, or by extending to the inner surface of the side wall of the battery can beyond the area of ​​the inner surface. Claim 16 A cylindrical secondary battery according to claim 1, wherein the insulating coating layer comprises one or more materials selected from the group consisting of epoxy, ceramic, and Teflon. Claim 17 A cylindrical secondary battery according to claim 1, characterized in that the end of the first electrode tab is bent in a direction parallel to the first current collector plate to form a coupling surface to which the first current collector plate is coupled. Claim 18 A cylindrical secondary battery according to claim 17, wherein the electrode assembly is in a shape in which a laminate of a first electrode, a separator, and a second electrode is wound with respect to a winding center, and the direction in which the end of the first electrode tab is bent is a direction toward the winding center of the electrode assembly.

Images