Cylindrical battery cell including composite current collector

Abstract

A cylindrical battery cell according to the present invention comprises: a battery case; and an electrode assembly including a first electrode and accommodated inside the battery case, wherein the first electrode comprises: a composite current collector including a positive electrode current collector and a negative electrode current collector facing the positive electrode current collector; a positive electrode active material layer formed on one surface of the positive electrode current collector so as to constitute a positive electrode; and a negative electrode active material layer formed on one surface of the negative electrode current collector so as to constitute a negative electrode.

Description

Cylindrical battery cell including a composite current collector

[0001] The present invention relates to a cylindrical battery cell comprising a composite current collector.

[0002] Lithium secondary batteries are classified according to the shape of the battery case into cylindrical batteries, in which the electrode assembly is cylindrical; prismatic batteries, in which the electrode assembly is embedded in a prismatic metal can; and pouch-type batteries, in which the electrode assembly is embedded in a pouch-type case made of aluminum laminate sheets.

[0003] The electrode assembly embedded in the battery case is a power generation element capable of charging and discharging, having a structure in which a positive electrode, a negative electrode, and a separator are interposed between the positive and negative electrodes. It is classified into a jelly-roll type, which is wound by interposing a separator between a long sheet-type positive and negative electrode coated with an active material; a stack type, which is sequentially stacked with a plurality of positive and negative electrodes of a predetermined size interposed in a separator; and a stack-folding type, which is wound by placing unit cells, such as a full cell (e.g., positive-separator-negative electrode) composed of electrodes with opposite polarities on both sides or a bicell (e.g., positive-separator-negative-separator-positive electrode) composed of electrodes with the same polarity on both sides, on a long sheet-type separator.

[0004] As jelly-roll type electrode assemblies are easy to manufacture and possess high energy-to-weight ratios, the demand for cylindrical secondary batteries is surging alongside the expansion of the market for EVs and HEVs that use jelly-rolls as a power source.

[0005] The present invention provides a cylindrical battery cell in which a negative electrode and a positive electrode are formed respectively on both sides of a composite current collector.

[0006] A cylindrical battery cell according to the present invention comprises a battery case and an electrode assembly that includes a first electrode and is housed inside the battery case. The first electrode may include a composite current collector comprising a positive current collector and a negative current collector facing the positive current collector, a positive active material layer formed on one surface of the positive current collector to form a positive electrode, and a negative active material layer formed on one surface of the negative current collector to form a negative electrode.

[0007] The negative current collector may be composed of a different composition from the positive current collector.

[0008] The composite current collector may further include an insulator disposed between the positive current collector and the negative current collector to prevent an electrical short circuit.

[0009] The electrode assembly may further include a second electrode having the same structure as the first electrode, and a separator disposed between the first electrode and the second electrode.

[0010] The separator may include at least one separator disposed above the first electrode, between the first electrode and the second electrode, or below the second electrode.

[0011] One side of the insulator is in contact with the other side of the positive current collector, and the other side of the insulator may be in contact with the other side of the negative current collector.

[0012] The above electrode assembly can be configured as a jelly-roll type cylinder so as to be wound into various shapes.

[0013] The above positive current collector may include aluminum (Al), and the above negative current collector may include copper (Cu).

[0014] The sizes of the positive current collector, the negative current collector, and the insulator may be the same.

[0015] The length of the anode current collector, the length of the cathode current collector, or the length of the insulator may differ from each other in a length direction orthogonal to the stacking direction.

[0016] The length of the insulator may be longer than the length of the positive active material layer or the length of the negative active material layer in a longitudinal direction orthogonal to the stacking direction.

[0017] The length of the above-mentioned negative active material layer may be longer than the length of the above-mentioned positive active material layer in a longitudinal direction orthogonal to the stacking direction.

[0018] The thickness of the anode current collector may differ from the thickness of the cathode current collector in the stacking height direction.

[0019] The above insulator may include polymer materials or ceramic particles.

[0020] The battery pack according to the present invention may include one or more cylindrical battery cells as described above.

[0021] An electric vehicle according to the present invention may include a battery pack as described above.

[0022] The present invention includes a composite current collector in which a cathode and an anode are formed on each side, thereby reducing dead volume and improving energy density compared to a method of winding the anode and cathode separately.

[0023] The present invention includes a composite current collector in which a cathode and an anode are formed on each side, thereby simplifying the structure of the electrode assembly and enabling cell diversity through various winding directions and shapes.

[0024] 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.

[0025] FIG. 1 is a drawing illustrating a cylindrical battery cell of the present invention.

[0026] FIG. 2 is a cross-sectional view of a cylindrical battery cell of the present invention.

[0027] FIG. 3 is a drawing illustrating an electrode assembly in a cylindrical battery cell including a composite current collector according to the present invention.

[0028] FIG. 4 is a drawing showing the appearance of an electrode assembly before it is wound in a cylindrical battery cell including a composite current collector according to one embodiment of the present invention.

[0029] FIG. 5 is a vertical cross-sectional view of an electrode assembly before being wound in a cylindrical battery cell including a composite current collector according to one embodiment of the present invention.

[0030] FIG. 6 is a vertical cross-sectional view of an electrode assembly before being wound in a cylindrical battery cell including a composite current collector according to another embodiment of the present invention.

[0031] Figure 7 is a drawing illustrating a battery pack in the present invention.

[0032] FIG. 8 is a drawing illustrating an electric vehicle equipped with a battery pack according to the present invention.

[0033] 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.

[0034] The embodiments described in this specification and the configurations illustrated in the drawings are merely examples of the disclosed invention, and various modifications that may replace the embodiments and drawings of this specification may exist at the time of filing this application.

[0035] Additionally, the same reference numbers or symbols presented in each figure of this specification represent parts or components that perform substantially the same function. Furthermore, the terms used in this specification are for describing embodiments and are not intended to limit or / or restrict the disclosed invention. Singular expressions include plural expressions unless the context clearly indicates otherwise.

[0036] In this specification, 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 do not preclude the existence or addition of one or more other features, numbers, steps, actions, components, parts, or combinations thereof.

[0037] Additionally, terms including ordinal numbers, such as "first," "second," etc., used in this specification may be used to describe various components, but said components are not limited by said terms, and said terms are used solely for the purpose of distinguishing one component from another.

[0038] For example, without departing from the scope of the present invention, the first component may be named the second component, and similarly, the second component may also be named the first component.

[0039] The term "and / or" includes a combination of multiple related listed items or any of the multiple related listed items.

[0040] Meanwhile, terms such as “front,” “rear,” “upper,” and “lower” used in the following description are defined based on the drawings, and the shape and location of each component are not limited by these terms.

[0041] The energy density of the internal jelly rolls of currently mass-produced cylindrical secondary batteries has reached its maximum level, and there is a need to improve cell performance by simplifying electrode designs to produce denser jelly rolls to reduce dead volume per unit volume, or by diversifying winding methods.

[0042] Lithium secondary batteries use a unit electrode in which the same electrode is formed on both sides of a current collector, for example, a unit electrode in which a negative electrode is formed on both sides of a copper current collector or a positive electrode is formed on both sides of an aluminum current collector.

[0043] An electrode assembly is manufactured by cross-stacking unit electrodes with negative electrodes formed on both sides of a copper current collector and unit electrodes with positive electrodes formed on both sides of an aluminum current collector with a separator in between.

[0044] To connect the two types of unit electrodes, additional welding processes are required, such as welding the aluminum current collector tab and the copper current collector tab, respectively, to the positive and negative lead tabs of the battery.

[0045] When manufacturing lithium secondary batteries in this way, tabs must be formed to connect unit electrodes, which increases the weight and volume of the battery and makes it difficult to miniaturize and lighten the battery. In addition, welding defects may occur during the additional welding process, which can lead to a decrease in battery performance.

[0046] Considering these points, the present invention provides a secondary battery structure that includes a composite current collector in which a negative electrode and a positive electrode are formed on each side, thereby reducing dead volume and improving energy density compared to a method of winding the positive and negative electrodes separately.

[0047] Hereinafter, embodiments according to the present invention will be described in detail with reference to the attached drawings.

[0048] FIG. 1 is a drawing illustrating a cylindrical battery cell of the present invention. FIG. 2 is a drawing illustrating a longitudinal section of a cylindrical battery cell of the present invention. FIG. 3 is a drawing illustrating an electrode assembly in a cylindrical battery cell including a composite current collector according to the present invention.

[0049] A cylindrical battery cell (10) including a composite current collector according to the present invention may form a cylindrical shape in which an electrode assembly (11) is embedded in a cylindrical can. The cylindrical battery cell (10) may include a jelly-roll shaped electrode assembly (11) and a battery case (12) for accommodating the electrode assembly (11).

[0050] An upper insulating member (15) may be disposed at the top of the electrode assembly (11), and a lower insulating member (16) may be disposed at the bottom of the electrode assembly (11).

[0051] The electrode assembly (11) is a jelly-roll shaped structure formed by winding a first electrode (110) and a separator (100) positioned above or below the first electrode (110), and a center pin (14) can be inserted in the center thereof.

[0052] A cylindrical battery cell (10) can be formed by housing an electrode assembly (11) in a battery case (12), injecting an electrolyte into the battery case (12), and then attaching a cap assembly (13) to the top of the battery case (12).

[0053] The battery case (12) is cylindrical, and a jelly-roll type electrode assembly (11) is housed in the cylindrical battery case (12) to realize a cylindrical secondary battery.

[0054] The battery case (12) may include a beading portion (12b) and a crimping portion (12a). The beading portion (12b) is for stable coupling of the cap assembly (13) and may be formed along the circumferential direction on the upper outer surface of the battery case (12) or may be formed by being concavely indented from the outer surface of the battery case (12) toward the center of the electrode assembly (11). The beading portion (12b) can prevent movement of the electrode assembly (11).

[0055] The crimping portion (12a) may be positioned on the upper part of the beading portion (12b) and formed to wrap around the edge portion of the cap assembly (13) along the circumferential direction. The crimping portion (12a) can facilitate a stable connection of the cap assembly (13).

[0056] The cap assembly (13) may include an upper cap (13a) forming an electrode terminal, a cap plate (13b), and a sealing gasket (13c). The gasket (13c) may be mounted on the upper inner surface of the crimping portion (12a) and the beading portion (12b) to increase the sealing force between the cap assembly (13) and the battery case (12).

[0057] The center pin (14) may generally include a metal material to provide a certain strength and may be formed into a cylindrical structure formed by bending a plate into a round shape. In addition to self-heating, the center pin (14) may function as a passage to fix and support the electrode assembly (11) and to release gas generated by internal reactions during charging, discharging, and operation.

[0058] The electrolyte injected into the battery case (12) may be a lithium salt-containing non-aqueous electrolyte, and the lithium salt-containing non-aqueous electrolyte may include a non-aqueous electrolyte and a lithium salt. As the non-aqueous electrolyte, a non-aqueous organic solvent, an organic solid electrolyte, an inorganic solid electrolyte, etc. may be used. However, it is not limited thereto.

[0059] The electrode assembly (11) may include a first electrode (110) in the shape of a long sheet and a separator (100) disposed above or below the first electrode (110). A cylindrical battery cell (10) including a composite current collector according to the present invention may have a single electrode, such that the positive and negative electrodes are combined on the first electrode (110), and the electrode assembly (11) may be composed solely of the first electrode (110) which is a single electrode.

[0060] The electrode assembly (11) according to the present invention may include a second electrode (120) having the same structure as the first electrode (110). The electrode assembly (11) may include a plurality of electrodes, including the first electrode (110) and the second electrode (120).

[0061] A separator (100) may be disposed between a first electrode (110) and a second electrode (120). The separator (100) may include a plurality of separators (100) disposed above or below the first electrode (110) and between the first electrode (110) and the second electrode (120).

[0062] A separator (100) may be placed above or below the first electrode (110) and, when the first electrode (110) and the second electrode (120) are wound together in a jelly-roll shape, physically separate the positive electrode included in the first electrode (110) and the negative electrode included in the second electrode (120) to prevent an electrical short circuit between the positive electrode and the negative electrode. Alternatively, the separator (100) may physically separate the negative electrode included in the first electrode (110) and the positive electrode included in the second electrode (120) to prevent an electrical short circuit between the negative electrode and the positive electrode.

[0063] For example, in FIG. 2, the electrode assembly (11) according to the present invention is shown to include both a first electrode (110) and a second electrode (120), but is not limited thereto, and the electrode assembly (11) according to the present invention may be composed only of a single electrode, the first electrode (110).

[0064] Additionally, the electrode assembly (11) according to the present invention may include a plurality of electrodes, including a first electrode (110) and a second electrode (120), and may include a plurality of separators (100) disposed on the upper or lower part of the first electrode (110) or on the upper or lower part of the second electrode (120).

[0065] A separator (100) may be additionally placed under the second electrode (120) to prevent the first electrode (110) and the second electrode (120) from coming into contact when wound in a jelly-roll shape.

[0066] A sealing tape (17) may be placed on the outer surface of the electrode assembly (11). The sealing tape (17) may be placed on the upper and lower portions, respectively, of the outer surface of the electrode assembly (11). The sealing tape (17) may be placed along the circumferential direction on the outer surface of the electrode assembly (11) in the form of a jelly-roll, and may be attached to the outer surface of the electrode assembly (11) by an adhesive layer on the lower surface of the sealing tape (17).

[0067] Although the embodiments of the present invention have been described primarily with respect to cylindrical battery cells, the present invention is not limited thereto and is applicable to other types of battery cells, such as prismatic battery cells or pouch-type battery cells.

[0068] FIG. 4 is a drawing showing the appearance of an electrode assembly before being wound in a cylindrical battery cell including a composite current collector according to one embodiment of the present invention. FIG. 5 is a vertical cross-sectional view of an electrode assembly before being wound in a cylindrical battery cell including a composite current collector according to one embodiment of the present invention.

[0069] Referring to FIGS. 4 and 5, the electrode assembly (11, see FIG. 2) may include a first electrode (110) and a second electrode (120). The first electrode (110) and the second electrode (120) may be identical. However, they are not limited thereto. Hereinafter, the first electrode (110) including a composite current collector (114) according to one embodiment of the present invention will be described based on the first electrode (110).

[0070] The first electrode (110) may include a composite current collector (114), a positive active material layer (115) formed on one side of the composite current collector (114), and a negative active material layer (116) formed on the other side of the composite current collector (114).

[0071] The positive active material layer (115) and the negative active material layer (116) may be formed facing each other with a composite current collector (114) in between. According to one embodiment, a cylindrical battery cell (10, see FIG. 2) including a composite current collector (114) according to the present invention may have a positive electrode (117) and a negative electrode (118) formed together on a single electrode, thereby simplifying the design of the electrode, and may configure the jelly-roll cylindrical battery cell (10, see FIG. 2) in various ways by applying various winding directions and shapes.

[0072] Through this, the electrochemical reaction area can be maximized and the output characteristics of the battery can be improved. In addition, cylindrical battery cells of various sizes and shapes (10, see FIG. 2) can be manufactured, which can expand the range of applications and enable customized battery designs tailored to specific applications.

[0073] Referring to FIG. 5, the first electrode (110) may include a positive electrode (117) and a negative electrode (118). The positive electrode (117) may include a positive current collector (111) and a positive active material layer (115), and the negative electrode (118) may include a negative current collector (112) and a negative active material layer (116).

[0074] Additionally, an insulator (113) may be included between the positive current collector (111) and the negative current collector (112) to prevent an electrical short circuit.

[0075] The composite current collector (114) according to the present invention may include a positive current collector (111), a negative current collector (112), and an insulator (113). Additionally, the positive current collector (111) and the negative current collector (112) may be composed of different compositions.

[0076] The positive current collector (111) may include aluminum (Al) to form a positive electrode (117) together with a positive active material layer (115), and the negative current collector (112) may include copper (Cu) to form a negative electrode (118) together with a negative active material layer (116). However, the present invention is not limited thereto.

[0077] The positive active material layer (115) may be formed on one side of the positive current collector (111) to form the positive electrode (117), and the negative active material layer (116) may be formed on one side of the negative current collector (112) to form the negative electrode (118). The other side of the positive current collector (111) and the other side of the negative current collector (112) may be arranged facing each other. The positive active material layer (115) may be formed by coating the positive current collector (111), and the negative active material layer (116) may be formed by coating the negative current collector (112).

[0078] The positive electrode active material layer (115) may have a nanostructure, which can improve electrical conductivity and increase the surface area of ​​the positive electrode (117), thereby improving the electrochemical reaction rate. The negative electrode active material layer (116) may contain graphite and may undergo surface modification treatment to maximize reactivity with lithium ions.

[0079] The composite current collector (114) according to the present invention can prevent an electrical short circuit between the positive electrode (117) and the negative electrode (118) by including an insulator (113). By placing an insulator (113) between the positive current collector (111) and the negative current collector (112), a composite current collector (114) including the positive current collector (111) and the negative current collector (112) can be realized, and the positive electrode (117) and the negative electrode (118) can be formed together on a single first electrode (110). The insulator (113) may be composed of a different composition from the separator (100, see FIG. 2).

[0080] One side of the insulator (113) may face the other side of the positive current collector (111), and the other side of the insulator (113) may face the other side of the negative current collector (112). One side of the insulator (113) may be in contact with the other side of the positive current collector (111), and the other side of the insulator (113) may be in contact with the other side of the negative current collector (112).

[0081] Meanwhile, in the first electrode (110) according to one embodiment of the present invention, a positive active material layer (115) is formed above the positive current collector (111) and a negative active material layer (116) is formed below the negative current collector (112), based on FIG. 5, but the present invention is not limited thereto. For example, in the first electrode (110) according to another embodiment of the present invention, a positive active material layer (115) may be formed below the positive current collector (111) and a negative active material layer (116) may be formed above the negative current collector (112). In this case, one side of the insulator (113) may face the other side of the positive active material layer (115), and the other side of the insulator (113) may face the other side of the negative active material layer (116). Alternatively, in the first electrode (110) according to another embodiment of the present invention, a positive active material layer (115) and a negative active material layer (116) may be formed on both sides of the positive current collector (111) and the negative current collector (112), respectively.

[0082] According to one embodiment, the insulator (113) may include a polymer material or ceramic particles. This allows for thermal stability and electrical insulation, and the ceramic particles can prevent an electrical short circuit between the anode (117) and the cathode (118) and maintain stable characteristics even in a high-temperature environment. However, the present invention is not limited thereto.

[0083] The size of the positive current collector (111) may be the same as the size of the negative current collector (112). The length of the positive current collector (111) may be the same as the length of the negative current collector (112) in the length direction perpendicular to the stacking direction. The thickness of the positive current collector (111) may be the same as the thickness of the negative current collector (112) in the height direction in which it is stacked. The area of ​​one side of the positive current collector (111) may be the same as the area of ​​one side of the negative current collector (112). However, the present invention is not limited thereto.

[0084] According to one embodiment, the size of the positive current collector (111) may be the same as the size of the insulator (113). The length of the positive current collector (111) may be the same as the length of the insulator (113) in the length direction perpendicular to the stacking direction. The thickness of the positive current collector (111) may be the same as the thickness of the insulator (113) in the height direction in which it is stacked. The area of ​​one side of the positive current collector (111) may be the same as the area of ​​one side of the insulator (113). However, the present invention is not limited thereto.

[0085] According to one embodiment, the size of the negative current collector (112) may be the same as the size of the insulator (113). The length of the negative current collector (112) may be the same as the length of the insulator (113) in the length direction perpendicular to the stacking direction. The thickness of the negative current collector (112) may be the same as the thickness of the insulator (113) in the height direction in which it is stacked. The area of ​​one side of the negative current collector (112) may be the same as the area of ​​one side of the insulator (113). However, the present invention is not limited thereto.

[0086] According to one embodiment, the size of the positive current collector (111), the size of the negative current collector (112), or the size of the insulator (113) may be the same as each other. The length of the positive current collector (111), the length of the negative current collector (112), or the length of the insulator (113) may be the same as each other in the length direction perpendicular to the stacking direction. The thickness of the positive current collector (111), the thickness of the negative current collector (112), or the thickness of the insulator (113) may be the same as each other in the height direction of stacking. The area of ​​one side of the positive current collector (111), the area of ​​one side of the negative current collector (112), or the area of ​​one side of the insulator (113) may be the same as each other. However, the present invention is not limited thereto.

[0087] According to one embodiment, the length of the insulator (113) may be longer than the length of the positive active material layer (115) or the negative active material layer (116) in a longitudinal direction orthogonal to the stacking direction. The length of the positive current collector (111) may be longer than the length of the positive active material layer (115) or the negative active material layer (116) in a longitudinal direction orthogonal to the stacking direction. The length of the negative current collector (112) may be longer than the length of the positive active material layer (115) or the negative active material layer (116) in a longitudinal direction orthogonal to the stacking direction. However, the present invention is not limited thereto.

[0088] According to one embodiment, the length of the negative active material layer (116) may be longer than the length of the positive active material layer (115) in a longitudinal direction orthogonal to the stacking direction. However, the present invention is not limited thereto.

[0089] According to one embodiment, an electrode assembly (11, see FIG. 2) including a composite current collector (114) according to the present invention may be configured in a cylindrical shape. An electrode assembly (11, see FIG. 2) including a composite current collector (114) may be configured in a jelly-roll shape so as to be wound in various forms. Through this, a first electrode (110), which is a single electrode including a positive electrode (117) and a negative electrode (118), can be applied to a jelly-roll cylindrical battery cell (10, see FIG. 2).

[0090] FIG. 6 is a vertical cross-sectional view of an electrode assembly before being wound in a cylindrical battery cell including a composite current collector according to another embodiment of the present invention.

[0091] Referring to FIG. 6, the electrode assembly (11, see FIG. 2) may include a second electrode (120). The first electrode (110) and the second electrode (120) may be different from each other. The first electrode (110) and the second electrode (120) may have different compositions. Hereinafter, the second electrode (120) including a composite current collector (124) according to another embodiment of the present invention will be described based on the second electrode (120).

[0092] The second electrode (120) may include a composite current collector (124), a positive active material layer (125) formed on one side of the composite current collector (124), and a negative active material layer (126) formed on the other side of the composite current collector (124).

[0093] The positive active material layer (125) and the negative active material layer (126) can be formed facing each other with a composite current collector (124) in between. For example, in a cylindrical battery cell (10, see FIG. 2) including a composite current collector (124) according to the present invention, the positive electrode (127) and the negative electrode (128) can be formed together on a single electrode. Through this, the design of the electrode can be simplified, and the jelly-roll cylindrical battery cell can be configured in various ways by applying various winding directions and shapes.

[0094] The second electrode (120) may include a positive electrode (127) and a negative electrode (128). The positive electrode (127) may include a positive current collector (121) and a positive active material layer (125), and the negative electrode (128) may include a negative current collector (122) and a negative active material layer (126).

[0095] The composite current collector (124) according to the present invention may include a positive current collector (121) and a negative current collector (122). The positive current collector (121) and the negative current collector (122) may be composed of different compositions.

[0096] The positive current collector (121) may include aluminum (Al) to form a positive electrode (127) together with the positive active material layer (125), and the negative current collector (122) may include copper (Cu) to form a negative electrode (128) together with the negative active material layer (126). However, it is not limited thereto.

[0097] The positive active material layer (125) can be formed by coating an electrode active material on one surface of the positive current collector (121). The negative active material layer (126) can be formed by coating an electrode active material on one surface of the negative current collector (122).

[0098] The positive active material layer (125) may be formed on one side of the positive current collector (121) to form the positive electrode (127), and the negative active material layer (126) may be formed on one side of the negative current collector (122) to form the negative electrode (128). The other side of the positive current collector (121) and the other side of the negative current collector (122) may be arranged facing each other.

[0099] The composite current collector (124) may include an insulator (123) disposed between the positive current collector (121) and the negative current collector (122). By including the insulator (123), the composite current collector (124) according to the present invention can prevent an electrical short circuit between the positive electrode (127) and the negative electrode (128). Through this, a composite current collector (124) including the positive current collector (121) and the negative current collector (122) can be implemented, and the positive electrode (127) and the negative electrode (128) can be formed together on a single second electrode (120).

[0100] One side of the insulator (123) may face the other side of the positive current collector (121), and the other side of the insulator (123) may face the other side of the negative current collector (122). One side of the insulator (123) may be in contact with the other side of the positive current collector (121), and the other side of the insulator (123) may be in contact with the other side of the negative current collector (122).

[0101] Meanwhile, in the second electrode (120) according to one embodiment of the present invention, a positive active material layer (125) is formed above the positive current collector (121) and a negative active material layer (126) is formed below the negative current collector (122), but the present invention is not limited thereto. For example, in the second electrode (120) according to another embodiment of the present invention, a positive active material layer (125) may be formed below the positive current collector (121) and a negative active material layer (126) may be formed above the negative current collector (122). In this case, one side of the insulator (123) may face the other side of the positive active material layer (125), and the other side of the insulator (123) may face the other side of the negative active material layer (126). Alternatively, in the second electrode (120) according to another embodiment of the present invention, a positive active material layer (125) and a negative active material layer (126) may be formed on both sides of the positive current collector (121) and the negative current collector (122), respectively.

[0102] According to one embodiment, the insulator (123) may include a polymer material or ceramic particles. This allows for thermal stability and electrical insulation, and the ceramic particles can prevent an electrical short circuit between the anode (127) and the cathode (128) and maintain stable characteristics even in a high-temperature environment. However, the present invention is not limited thereto.

[0103] According to one embodiment, the size of the positive current collector (121) may differ from the size of the negative current collector (122). The thickness of the positive current collector (121) may differ from the thickness of the negative current collector (122) in the stacking height direction. The length of the positive current collector (121) may differ from the length of the negative current collector (122) in the length direction perpendicular to the stacking direction. The surface area of ​​one side of the positive current collector (121) may differ from the surface area of ​​one side of the negative current collector (122).

[0104] According to one embodiment, the size of the positive current collector (121) may differ from the size of the insulator (123). The thickness of the positive current collector (121) may differ from the thickness of the insulator (123) in the stacking height direction. The length of the positive current collector (121) may differ from the length of the insulator (123) in the length direction perpendicular to the stacking direction. The area of ​​one side of the positive current collector (121) may differ from the area of ​​one side of the insulator (123).

[0105] According to one embodiment, the size of the negative current collector (122) may differ from the size of the insulator (123). The thickness of the negative current collector (122) may differ from the thickness of the insulator (123) in the stacking height direction. The length of the negative current collector (122) may differ from the length of the insulator (123) in the length direction perpendicular to the stacking direction. The area of ​​one side of the negative current collector (122) may differ from the area of ​​one side of the insulator (123).

[0106] According to one embodiment, the size of the positive current collector (121), the size of the negative current collector (122), or the size of the insulator (123) may differ from one another. The thickness of the positive current collector (121), the thickness of the negative current collector (122), or the thickness of the insulator (123) may differ from one another in the height direction in which they are stacked. The length of the positive current collector (121), the length of the negative current collector (122), or the length of the insulator (123) may differ from one another in the length direction perpendicular to the direction in which they are stacked. The area of ​​one side of the positive current collector (121), the area of ​​one side of the negative current collector (122), or the area of ​​one side of the insulator (123) may differ from one another.

[0107] For example, the size and length of the positive current collector (121), negative current collector (122), or insulator (123) can be adjusted according to the design of the cylindrical battery cell (10, see FIG. 2). For example, the length of the insulator (123) can be designed to be longer than the length of the positive active material layer (125) and the negative active material layer (126) in a longitudinal direction orthogonal to the stacking direction to enhance insulation, and by preventing contact between the positive (127) and the negative (128), the safety and performance of the battery can be improved.

[0108] FIG. 7 is a drawing illustrating a battery pack in the present invention. FIG. 8 is a drawing illustrating an electric vehicle equipped with a battery pack in the present invention.

[0109] Referring to FIGS. 7 and 8, a plurality of cylindrical battery cells (10) can be accommodated in a pack case (2100) to form a battery pack (2000). The battery pack (2000) may additionally include various control and protection systems such as a Battery Management System (BMS).

[0110] The battery pack (2000) can be applied to various devices. For example, it can be applied to means of transportation such as electric bicycles, electric vehicles, and hybrid vehicles, or to an Energy Storage System (ESS), but is not limited to these and can be applied to various devices that can use secondary batteries.

[0111] In an electric vehicle (V), the wheel is driven by a motor that receives power from a battery pack (2000), and the electric vehicle can be operated.

[0112] Although the technical concept of the present invention has been explained above through specific embodiments, the scope of the present invention is not limited to these embodiments.

[0113] Various embodiments that can be modified or varied by a person skilled in the art, within the scope of not departing from the gist of the technical concept of the present invention as specified in the patent claims, shall also be deemed to fall within the scope of the rights of the present invention.

Claims

1. Battery case; and an electrode assembly comprising a first electrode and accommodated inside the battery case; The first electrode above is, A composite current collector comprising a positive current collector and a negative current collector facing the positive current collector, A positive active material layer formed on one surface of the positive current collector to constitute a positive electrode, and A cylindrical battery cell comprising a negative active material layer formed on one surface of the negative current collector to form a negative electrode.

2. In Paragraph 1, The above negative current collector is a cylindrical battery cell composed of a different composition from the above positive current collector.

3. In Paragraph 1, The above composite current collector is a cylindrical battery cell further comprising an insulator disposed between the positive current collector and the negative current collector to prevent an electrical short circuit.

4. In Paragraph 1, The above electrode assembly is, A second electrode having the same structure as the first electrode, and A cylindrical battery cell further comprising a separator disposed between the first electrode and the second electrode.

5. In Paragraph 4, The above separator is a cylindrical battery cell comprising at least one separator disposed above the first electrode, between the first electrode and the second electrode, or below the second electrode.

6. In Paragraph 3, One side of the insulator is in contact with the other side of the positive current collector, and A cylindrical battery cell in which the other side of the insulator is in contact with the other side of the negative current collector.

7. In Paragraph 1, The above electrode assembly is a cylindrical battery cell that forms a jelly-roll type cylinder so as to be wound into various shapes.

8. In Paragraph 1, The above positive current collector comprises aluminum (Al), and The above negative current collector is a cylindrical battery cell containing copper (Cu).

9. In Paragraph 3, A cylindrical battery cell having the same size as the positive current collector, the negative current collector, and the insulator.

10. In Paragraph 3, A cylindrical battery cell in which the length of the positive current collector, the length of the negative current collector, or the length of the insulator are different in a longitudinal direction perpendicular to the stacking direction.

11. In Paragraph 3, A cylindrical battery cell in which the length of the insulator is longer than the length of the positive active material layer or the length of the negative active material layer in a longitudinal direction orthogonal to the stacking direction.

12. In Paragraph 1, A cylindrical battery cell in which the length of the negative active material layer is longer than the length of the positive active material layer in a longitudinal direction orthogonal to the stacking direction.

13. In Paragraph 1, A cylindrical battery cell in which the thickness of the positive current collector is different from the thickness of the negative current collector in the stacking height direction.

14. In Paragraph 3, The above insulator is a cylindrical battery cell comprising a polymer material or ceramic particles.

15. A battery pack comprising a cylindrical battery cell according to claim 1.

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