KR-20260066487-A - Electrode Assembly with Improved Electrolyte Impregnation

KR20260066487AKR 20260066487 AKR20260066487 AKR 20260066487AKR-20260066487-A

Abstract

The present invention provides an electrode assembly having a cut line formed along the width direction of the electrode tab in a bent area of the electrode tab. The electrode tab is bent in the radial direction of the electrode assembly at a bend line extending in the width direction of the electrode tab. The electrode tab may include a plurality of split tabs formed by a cut line spaced apart along the circumferential direction of the electrode assembly. At least one of the split tabs may include the cut line. The electrode tab or the split tab may include a first cut line formed adjacent to the bend line and a second cut line formed at a predetermined distance from the first cut line. The electrode tab or the split tab may include the first cut line, the second cut line, and a third cut line formed at a predetermined distance from the second cut line. The electrode tab or the split tab may include an impregnation hole penetrating the electrode tab in the thickness direction of the electrode tab in the bent area of the electrode tab.

Inventors

장진수
이명안
홍지훈

Assignees

주식회사 엘지에너지솔루션

Dates

Publication Date: 20260512
Application Date: 20241104

Claims (18)

A jelly-roll type electrode assembly wound around a core axis, wherein the first electrode and the second electrode are alternately stacked with a separator in between. The first electrode comprises a retaining portion on which an active material is coated on the surface of a current collector and an uncoated portion on which an active material is not coated on the surface of the current collector. At least a portion of the above-mentioned non-removable portion extends further outward from the separator at an axial end portion of the electrode assembly to define at least a portion of the electrode tab of the first electrode, and The electrode tab is bent in the radial direction of the electrode assembly at a bending line extending in the width direction of the electrode tab corresponding to the circumferential direction of the electrode assembly, and An electrode assembly having one or more incision lines formed adjacent to the incision line and along the width direction of the electrode tab, wherein the electrode tab is cut in the thickness direction of the electrode tab and the electrode tab is cut in the bending area that is bent to extend radially from the electrode tab by a bending line.
In claim 1, The electrode tab comprises a plurality of divided tabs formed by a spaced-apart cut line along the circumferential direction of the electrode assembly. At least one of the above-mentioned split tabs is an electrode assembly including the above-mentioned cut line.
In claim 2, An electrode assembly comprising at least one of the above-mentioned split tabs, the first cut line formed adjacent to a bending line and a second cut line formed at a predetermined distance in the radial direction from the first cut line.
In claim 3, An electrode assembly comprising at least one of the above-mentioned split tabs, the third split line formed at a predetermined distance in the radial direction from the second split line.
In claim 2, An electrode assembly comprising at least one of the above-mentioned split tabs, the first cutting line formed adjacent to a bending line and a first impregnation hole formed spaced apart from the first cutting line by a first interval in the radial direction.
In claim 5, The above first interval is equal to or greater than the lead length of the winding turn, and An electrode assembly in which the radial length of the first impregnation hole is greater than the lead length.
In claim 5, An electrode assembly comprising at least one of the above-mentioned split tabs, the second impregnation hole formed by a second interval in the radial direction from the first impregnation hole.
In claim 7, The above second interval is smaller than the lead length of the winding turn, and An electrode assembly in which the radial length of the first impregnation hole and the radial length of the second impregnation hole are greater than the lead length.
In any one of claims 1 to 8, The above-mentioned incision line comprises a first incision formed along the width direction of the electrode tab and a second incision connected to the first incision and formed along the radial direction, forming an electrode assembly.
A jelly-roll type electrode assembly wound around a core axis, wherein the first electrode and the second electrode are alternately stacked with a separator in between. The first electrode comprises a retaining portion on which an active material is coated on the surface of a current collector and an uncoated portion on which an active material is not coated on the surface of the current collector. At least a portion of the above-mentioned non-removable portion extends further outward from the separator at an axial end portion of the electrode assembly to define at least a portion of the electrode tab of the first electrode, and The electrode tab is bent in the radial direction of the electrode assembly at a bending line extending in the width direction of the electrode tab corresponding to the circumferential direction of the electrode assembly, and An electrode assembly having one or more impregnation holes formed along the width direction of the electrode tab and penetrating the electrode tab in the thickness direction of the electrode tab and adjacent to the bending line, in a bending region that is bent to extend radially from the electrode tab by a bending line.
In claim 1, The above-mentioned impregnation hole is an electrode assembly having a shape including a circle, an ellipse, a square, or a triangle.
In claim 10, The above-mentioned impregnation hole is an electrode assembly in which the radial length is equal to or smaller than the lead length of the winding turn.
In claim 10, The electrode tab comprises a plurality of divided tabs formed by a spaced-apart cut line along the circumferential direction of the electrode assembly. At least one of the above-mentioned split tabs is an electrode assembly comprising the above-mentioned impregnation hole.
In claim 13, An electrode assembly comprising at least one of the above-mentioned split tabs, the third impregnation hole formed adjacent to a bending line and a fourth impregnation hole formed spaced apart from the third impregnation hole by a third interval in the radial direction.
In claim 14, The radial length of the third impregnation hole is equal to or smaller than the lead length of the winding turn, and The above third interval is an electrode assembly that is equal to or greater than the length of the lead.
In claim 15, An electrode assembly in which the radial length of the fourth impregnation hole is greater than the length of the lead.
In claim 14, An electrode assembly comprising at least one of the above-mentioned split tabs, the electrode assembly including a fifth impregnation hole formed at a fourth interval in the radial direction from the fourth impregnation hole.
In claim 17, The above-mentioned fourth interval is equal to or smaller than the length of the lead of the winding turn, and An electrode assembly in which the radial length of the fourth impregnation hole and the radial length of the fifth impregnation hole are greater than the lead length.

Description

Electrode Assembly with Improved Electrolyte Impregnation The present invention relates to an electrode assembly, and more specifically, to an electrode assembly that is housed inside the case of a secondary battery and has improved electrolyte impregnation properties. Rechargeable batteries, which possess electrical characteristics such as high energy density and high applicability across product categories, are widely applied not only to portable devices but also to electric vehicles or hybrid vehicles powered by electric sources, and power storage devices. These rechargeable batteries are attracting attention as a new energy source for enhancing eco-friendliness and energy efficiency, not only for the primary advantage of drastically reducing the use of fossil fuels but also because they generate no by-products from energy use. Secondary batteries are classified into cylindrical, pouch, and prismatic types according to their shape. Secondary batteries house an electrode assembly inside. A cylindrical secondary battery is a type in which a jelly-roll type electrode assembly is housed inside a cylindrical battery can. In the winding process, the winding device assembles the jelly-roll electrode assembly by winding the first electrode and the second electrode with a separator interposed therebetween. The electrode included in the electrode assembly is manufactured in the form of a sheet extending in the longitudinal direction with a predetermined width. The electrode is manufactured in a form in which an active material is coated on a current collector. The electrode includes not only a retaining portion, which is an area where the active material is coated on the current collector, but also an uncoated portion, which is an area where the active material is not coated on the current collector. The unsupported portion may be located at one end of the width direction of the retaining portion. The unsupported portion may include an electrode tab extending in the width direction along the length direction. The electrode tab may extend in the axial direction of the electrode assembly and serve as a passage for electron movement. In a subsequent process, the electrode tab can be welded to the current collector plate. Electrons from the electrode can move to the current collector plate through the electrode tab. To ensure a secure bond with the current collector plate, the electrode tab is bent parallel to the radial direction of the electrode assembly. The bent electrode tab of the first electrode and the bent electrode tab of the second electrode are each welded to a current collector plate, and the electrode assembly is inserted into a cylindrical battery can. An external cell terminal is provided at one axial end of the cylindrical battery can. The current collector plate welded to the electrode tab of either the first or second electrode is welded to the external cell terminal inside the cylindrical battery can. The current collector plate, which is not welded to the cell external terminal, is located at the other end of a cylindrical battery can that has an opening. The perimeter of the battery can adjacent to the current collector plate is bent inward by a device such as a beading knife to form a beading section. The beading section is welded to the current collector plate, and the electrode assembly is fixed inside the battery can. Subsequently, the cap plate closes the opening of the battery can. The opening end of the can, which extends further axially than the cap plate toward the other end, undergoes a crimping process in which it is bent inward and compressed against the cap plate. An insulator (gasket) may be interposed between the opening end of the can and the cap plate. Meanwhile, an electrolyte is applied as a medium to facilitate the smooth movement of lithium ions between the first electrode and the second electrode. The electrolyte can be injected into the battery can through an injection port provided in the cap plate. The injected electrolyte is impregnated into the active material of the electrode, thereby facilitating the smooth movement of lithium ions between the first electrode and the second electrode. However, according to the conventional electrode assembly structure, the electrode tabs are bent parallel to the radial direction and stacked axially, making it difficult for the electrolyte to pass through the electrode tabs and impregnate the electrodes. If the electrolyte is not sufficiently impregnated into the electrodes, problems such as reduced battery cell capacity or low voltage may occur. Meanwhile, since the electrode tab is bent radially from the arc-shaped current collector, the electrode tab forms a flat surface, whereas the bending line between the current collector and the electrode tab forms an arc shape, so the bending portion may become crumpled or the electrode tab may become crumpled. Therefore, there is an urgent need for an electrode assembly including an electrode