US-12626947-B2 - Lamination apparatus including pressing roll configured such that pressing force thereof is adjustable and electrode assembly manufactured using the same

US12626947B2US 12626947 B2US12626947 B2US 12626947B2US-12626947-B2

Abstract

The present invention relates to a lamination apparatus for manufacture of an electrode assembly, and more particularly to a lamination apparatus including a pressing roll configured to press electrodes constituting the electrode assembly, a rotary shaft configured to rotate the pressing roll, a pressing cylinder configured to adjust pressing force applied to the pressing roll, and a thickness measurement sensor configured to measure the thickness of one of the electrodes, whereby it is possible to secure the force of adhesion between the electrodes constituting the electrode assembly even though there is deviation in thickness between electrode mixture layers.

Inventors

Dong Ha Kim

Assignees

LG ENERGY SOLUTION, LTD.

Dates

Publication Date: 20260512
Application Date: 20220128
Priority Date: 20210205

Claims (9)

1 . A lamination apparatus for manufacture of an electrode assembly, the lamination apparatus comprising: a pressing roll configured to press electrodes constituting the electrode assembly; a rotary shaft configured to rotate the pressing roll; a pressing cylinder configured to adjust a pressing force applied to the pressing roll; and first and second thickness measurement sensors configured to respectively measure first and second thicknesses of an electrode mixture layer at opposite ends of one of the electrodes; and a controller configured to control the pressing force applied by the pressing cylinder when a difference occurs between the first thickness and the second thickness, wherein the pressing roll is configured to more strongly press the electrode assembly at a first position at which the thickness of the electrode mixture layer of the one of the electrodes is smaller when the difference occurs between the first thickness the second thickness.
2 . The lamination apparatus according to claim 1 , wherein the pressing cylinder is a first pressing cylinder, the lamination apparatus further comprising a second pressing cylinder, the first pressing cylinder and the second pressing cylinder coupled to opposite ends of the rotary shaft, respectively.
3 . The lamination apparatus according to claim 2 , wherein the lamination apparatus is configured such that a first pressing force applied by the first pressing cylinder to the electrode assembly and a second pressing force applied by the second pressing cylinder to the electrode assembly are different from each other.
4 . The lamination apparatus according to claim 1 , wherein the electrode assembly is a bi-cell having a structure in which a first electrode, a separator, a second electrode, a separator, and a third electrode are sequentially stacked.
5 . The lamination apparatus according to claim 1 , further comprising: a first electrode supply unit; a second electrode supply unit; and a third electrode supply unit, wherein the one of the electrodes is a second electrode supplied from the second electrode supply unit.
6 . The lamination apparatus according to claim 1 , wherein each of the electrodes is a double-sided electrode having electrode mixtures coated on opposite surfaces of an electrode current collector thereof.
7 . The lamination apparatus according to claim 6 , wherein the thickness measurement sensor comprises: a radiation portion configured to radiate a beta ray through the electrode; and a receiving portion configured to sense the beta ray radiated by the radiation portion, and the radiation portion is configured to be disposed at a first one of an upper surface or a lower surface of the one of the electrodes while the receiving portion is disposed at a second one of the upper surface or the lower surface.
8 . The lamination apparatus according to claim 6 , wherein the pressing roll is an upper pressing roll, the lamination apparatus further comprising a lower pressing roll, and an upper pressing force configured to be applied to a first end and a second end of the upper pressing roll configured to be disposed at an upper surface of the electrode assembly are configured to be set independent of a lower pressing force configured to be applied to a first end and a second end of the lower pressing roll configured to be disposed at a lower surface of the electrode assembly.
9 . The lamination apparatus according to claim 1 , wherein the pressing roll is configured to be heated.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry under 35 U.S.C. § 371 of International Application No. PCT/KR2022/001614, filed on Jan. 28, 2022, which claims priority to Korean Patent Application No. 10-2021-0016895, filed on Feb. 5, 2021, the disclosures of which are hereby incorporated herein by reference in their entireties. TECHNICAL FIELD The present invention relates to a lamination apparatus including a pressing roll configured such that pressing force thereof is adjustable and an electrode assembly manufactured using the same. More particularly, the present invention relates to a lamination apparatus including a pressing roll configured such that pressing force thereof is adjustable in order to prevent non-uniform force of adhesion between electrodes constituting a bi-cell due to deviation in thickness between the electrodes and an electrode assembly manufactured using the same. BACKGROUND ART With acceleration in capacity increase and energy density improvement of a lithium secondary battery, the lithium secondary battery has been used as an energy source for medium and large devices, such as a vehicle or a power storage system, as well as small devices, such as a portable electronic device. The lithium secondary battery may be manufactured using a method of receiving an electrode assembly, configured to have a structure in which a positive electrode, a separator, and a negative electrode are sequentially stacked, in a battery case and hermetically sealing the battery case. The electrode assembly includes a single-cell configured to have a structure in which a first electrode and a separator are stacked, a mono-cell configured to have a structure in which a first electrode, a separator, a second electrode, and a separator are stacked, and a bi-cell configured to have a structure in which a first electrode, a separator, a second electrode, a separator, and a third electrode are stacked. Each of the electrodes constituting the electrode assembly is manufactured by applying an electrode mixture to one surface or opposite surfaces of a thin current collector made of copper, aluminum, or nickel and drying and pressing the same. The electrodes thus manufactured go through the process of stacking and laminating the electrodes in the state in which a separator is interposed therebetween such that the electrodes are coupled to each other. When there occurs deviation in thickness between electrode mixture layers applied to the electrodes, however, the electrodes may be non-uniformly coupled to each other. In connection therewith, FIG. 1 is a view showing a bi-cell lamination process using a conventional lamination apparatus. Referring to FIG. 1, an electrode assembly is a bi-cell configured such that a first electrode 110, a separator 140, a second electrode 120, a separator 140, and a third electrode 130 are sequentially stacked. The thicknesses of electrode mixture layers 122 applied to opposite surfaces of an electrode current collector 121 of the second electrode 120 are not uniform. The left-side thickness of each of the electrode mixture layers is small, and the right-side thickness of each of the electrode mixture layers is large. A pair of pressing rolls 150 is disposed above the first electrode 110 and under the third electrode 130 to press the electrode assembly. At this time, the pressing rolls 150 apply uniform pressure to the entireties of the surfaces of the first electrode 110 and the third electrode 130 that abut the pressing rolls. As a result, it is difficult for the left sides of the electrode mixture layers 122 of the second electrode to be brought into tight contact with the left side of the first electrode and the left side of the third electrode 130. If adhesion is not achieved at an interface between the electrodes, as described above, non-uniform degradation of the electrodes may be caused, and lithium ions have difficulty moving, whereby resistance may be increased, and therefore performance of a lithium secondary battery may be lowered. Also, in a production process to manufacture a stacked and folded type electrode assembly, bi-cells must be disposed on a long sheet type separation film one by one, and an electrode separated from one bi-cell may be disposed together with another bi-cell. Such a problem may occur due to poor adhesion between the first electrode and the second electrode and between the third electrode and the second electrode when the thickness of the second electrode disposed at the middle, among the electrodes constituting the bi-cell, is non-uniform. Therefore, there is a need for technology capable of securing the force of coupling between all electrodes constituting a bi-cell when the thickness of an electrode mixture layer of the second electrode disposed at the middle, among the electrodes, is non-uniform. DISCLOSURE Technical Problem The present invention has been made in view of the above problems, and it is an object of