WO-2026095646-A1 - NEGATIVE ELECTRODE AND LITHIUM SECONDARY BATTERY COMPRISING SAME

WO2026095646A1WO 2026095646 A1WO2026095646 A1WO 2026095646A1WO-2026095646-A1

Abstract

The present invention relates to a negative electrode comprising: a negative electrode current collector; a first negative electrode active material layer located on the negative electrode current collector; and a second negative electrode active material layer located on the first negative electrode active material layer, wherein: the volume of pores included in the first negative electrode active material layer is 20% to 49% of the total volume of pores included in the entire first and second negative electrode active material layers; the first negative electrode active material layer includes a first negative electrode active material including natural graphite and a first silicon-based negative electrode active material; the second negative electrode active material layer includes a second negative electrode active material including artificial graphite and a second silicon-based negative electrode active material; and the content of the first silicon-based negative electrode active material included in the first negative electrode active material layer is greater than the content of the second silicon-based negative electrode active material included in the second negative electrode active material layer.

Inventors

PARK, JU EUN
KIM, BYUNG JU
YOON, DAE RO
PARK, SEUNG SOO

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260507
Application Date: 20251029
Priority Date: 20241031

Claims (14)

A negative electrode current collector; a first negative electrode active material layer located on the negative electrode current collector; and a second negative electrode active material layer located on the first negative electrode active material layer; are included. The volume of pores included in the first negative electrode active material layer is 11% to 49% of the total volume of pores included in the entire first negative electrode active material layer and the second negative electrode active material layer, and The first negative electrode active material layer comprises a first negative electrode active material including natural graphite and a first silicon-based negative electrode active material, and The second negative electrode active material layer comprises a second negative electrode active material including artificial graphite and a second silicon-based negative electrode active material, and A cathode in which the content of the first silicon-based cathode active material included in the first cathode active material layer is greater than the content of the second silicon-based cathode active material included in the second cathode active material layer.
In paragraph 1, A cathode in which the ratio ( X1 / X2 ) of the content of the first silicon-based cathode active material (X1) included in the first cathode active material layer and the content of the second silicon-based cathode active material ( X2 ) included in the second cathode active material layer is greater than 1 and less than or equal to 10.
In paragraph 1, The cathode, wherein the first silicon-based negative electrode active material is included in an amount of 5 to 30 weight percent based on the total weight of the first negative electrode active material.
In paragraph 1, The cathode, wherein the second silicon-based negative electrode active material is included in an amount of 1 to 20 weight percent based on the total weight of the second negative electrode active material.
In paragraph 1, The first cathode active material layer has a porosity of 15% to 30%, forming a cathode.
In paragraph 1, The second cathode active material layer is a cathode having a porosity of 20% to 35%.
In paragraph 1, A cathode, wherein the thickness of the first cathode active material layer is 35% to 50% of the total thickness of the first cathode active material layer and the second cathode active material layer.
In paragraph 1, The first silicon-based negative electrode active material and the second silicon-based negative electrode active material each comprise a Si/C composite, forming a negative electrode.
A lithium secondary battery comprising: an electrode assembly including a cathode, an anode, and a separator interposed between the cathode and the anode according to any one of claims 1 to 8; an electrolyte; and a battery case in which the electrode assembly and the electrolyte are housed.
In Paragraph 9, A lithium secondary battery, wherein the ratio of the diameter (R) of the lithium secondary battery to the height (h) of the lithium secondary battery is 0.4 or greater.
In Paragraph 9, The above lithium secondary battery is a lithium secondary battery that is a 46110 cell, a 48110 cell, a 4880 cell, or a 4680 cell.
In Paragraph 9, The above anode and cathode each include an unactive portion in which an active material layer is not formed, and A lithium secondary battery in which at least a portion of the unused portion of the positive electrode and the unused portion of the negative electrode defines an electrode tab.
In Paragraph 12, A lithium secondary battery in which a current collecting plate is coupled to each of the non-positive portion of the positive electrode and the non-negative portion of the negative electrode, and the current collecting plate is connected to an electrode terminal.
In Paragraph 12, The above-mentioned unbought portions of the anode and cathode can be folded independently but are processed into multiple segmented pieces, and A lithium secondary battery in which at least some of the plurality of segments are bent toward the winding center of the electrode assembly.

Description

Negative electrode and lithium secondary battery including the same Cross-citation with related applications The present application claims the benefit of priority based on Korean Patent Application No. 10-2024-0153034 filed on October 31, 2024 and Korean Patent Application No. 10-2025-0159607 filed on October 29, 2025, and all contents disclosed in said Korean patent application documents are incorporated into this specification. Technology field The present invention relates to a negative electrode and a lithium secondary battery including the same. Recently, lithium-ion batteries have been gaining attention as an energy source for electric vehicles. As the adoption of electric vehicles expands, there is an increasing demand for lithium-ion batteries that offer a longer driving range on a single charge and shorter charging times. A lithium secondary battery is generally manufactured by forming an electrode assembly by interposing a separator between a positive electrode, which contains a positive active material composed of a transition metal oxide containing lithium, and a negative electrode, which contains a negative active material capable of storing lithium ions; inserting the electrode assembly into a battery case; injecting a non-aqueous electrolyte that serves as a medium for transmitting lithium ions; and then sealing the case. The non-aqueous electrolyte is generally composed of a lithium salt and an organic solvent capable of dissolving the lithium salt. Conventionally, carbon-based materials such as natural graphite or synthetic graphite have been primarily used as negative active materials for lithium secondary batteries. However, such carbon-based negative active materials have slow reactivity with lithium and low capacity, which limits the realization of high capacity and rapid charging characteristics in secondary batteries utilizing them. Accordingly, there have been continuous attempts recently to apply silicon-based anode active materials, which have a higher capacity per unit weight compared to graphite. However, silicon-based active materials have a problem in that their volume expands by up to 400% during charging and discharging, which destroys the SEI film on the anode surface, degrades the active material, and results in inferior lifespan characteristics, as well as higher resistance compared to carbon-based anode active materials. Therefore, there is a need to develop a cathode that achieves high capacity while exhibiting excellent resistance characteristics and superior lifespan characteristics during rapid charging. FIG. 1 is a drawing showing the stacked state of an electrode assembly before winding according to the present invention. FIG. 2 is a cross-sectional view showing the structure of an electrode of an electrode assembly according to one embodiment of the present invention. FIG. 3 is a drawing for explaining the structure of an electrode assembly according to one embodiment of the present invention. FIG. 4 is a cross-sectional view showing the structure of a lithium secondary battery according to one embodiment of the present invention. FIG. 5 is a cross-sectional view showing the structure of a lithium secondary battery according to another embodiment of the present invention. FIG. 6 is a drawing for explaining a battery pack according to the present invention. The present invention will be described in more detail below. 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 invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention. The terms used in this specification are used merely to describe exemplary embodiments and are not intended to limit the invention. The singular expression includes the plural expression unless the context clearly indicates otherwise. In this specification, terms such as “comprising,” “having,” or “having” are intended to specify the existence of the implemented features, numbers, steps, components, or combinations thereof, and should be understood as not excluding in advance the existence or addition of one or more other features, numbers, steps, components, or combinations thereof. In the present invention, “pore volume” refers to the volume of pores contained in the electrode active material layer. At this time, pores contained within the electrode active material may not be considered. The pore volume is calculated from the nitrogen adsorption isotherm under a 77K liquid nitrogen atmosphere obtained using BELSORP-MAX (MicrotracBEL corp.) on the cut electrode cross-section after cutting the electrode cross-section, and is calculated using a BJH (Barrett-Joyner-Halenda) plot for pores with a diameter of 2 nm to 185 nm. For example, in the case of a cathode comprising a first cathode activ