KR-20260063131-A - CYLINDRICAL BATTERY CELL INCLUDING COMPOSITE CURRENT COLLECTOR

KR20260063131AKR 20260063131 AKR20260063131 AKR 20260063131AKR-20260063131-A

Abstract

A cylindrical battery cell comprising a composite current collector having different polarities formed on both sides is provided. The battery case includes a first electrode and an electrode assembly accommodated inside the battery case, wherein the first electrode comprises a composite current collector including 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.

Inventors

박지은
최은선

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260507
Application Date: 20241030

Claims (16)

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.
In Article 1, The above negative current collector is a cylindrical battery cell composed of a different composition from the above positive current collector.
In Article 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.
In Article 1, The above electrode assembly is a cylindrical battery cell further comprising a separator disposed above or below the first electrode to prevent an electrical short circuit between the positive electrode and the negative electrode.
In Paragraph 4, The above electrode assembly further includes a second electrode having the same structure as the first electrode, and The above separator is a cylindrical battery cell disposed between the first electrode and the second electrode.
In Article 5, The above separator is a cylindrical battery cell comprising a plurality of separators disposed on the upper part of the first electrode and between the first electrode and the second electrode.
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.
In Article 1, The above electrode assembly is a cylindrical battery cell that forms a cylinder.
In Article 8, The above electrode assembly is a cylindrical battery cell configured as a jelly-roll type so as to be wound into various shapes.
In Article 1, The above positive current collector comprises aluminum (Al), and The above negative current collector is a cylindrical battery cell containing copper (Cu).
In Paragraph 3, A cylindrical battery cell having the same size as the positive current collector, the negative current collector, and the insulator.
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.
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.
In Article 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.
In Article 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.
A battery pack comprising a cylindrical battery cell according to claim 1.

Description

Cylindrical battery cell including composite current collector The present invention relates to a cylindrical battery cell comprising a composite current collector having different polarities formed on both sides. 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. 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. 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. However, 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. 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. 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. 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. 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. FIG. 1 is a drawing illustrating a cylindrical battery cell of the present invention. FIG. 2 is a cross-sectional view 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. 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. 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. 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. Figure 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 according to the present invention. The embodiments described in this specification and the configurations illustrated in the drawings are merely preferred 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. 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