EP-4741811-A1 - AN INSPECTION APPARATUS, AND A METHOD, FOR DETECTING A DEFECT IN AN ELECTRODE TAB OF AN ELECTRODE ASSEMBLY

EP4741811A1EP 4741811 A1EP4741811 A1EP 4741811A1EP-4741811-A1

Abstract

An inspection apparatus (100) for detecting a defect (30) in an electrode tab (20) of an electrode assembly (10), wherein the electrode tab (20) is provided at a longitudinal end of the electrode assembly (10). The inspection apparatus (100) comprises a radiation emitting means (110) configured to emit an x-ray or a beta ray towards the electrode tab (20) and a radiation measuring means (120; 120a, 120b, 120c), disposed opposite the radiation emitting means (110) so as to have the electrode tab (20) positioned therebetween. The radiation measuring means (120; 120a, 120b, 120c) is configured to measure an amount of the x-ray or the beta ray transmitted through the electrode tab (20). The inspection apparatus (100) further comprises a processor (130) configured to process a signal corresponding to the measured amount of the x-ray or the beta ray and determine a defect (30) based on the amount of the x-ray or the beta ray measured at a portion within the electrode tab (20).

Inventors

CHOI, JIN HYEONG
HONG, JONG HYUK
LEE, GYU SUN

Assignees

LG Energy Solution, Ltd.

Dates

Publication Date: 20260513
Application Date: 20241107

Claims (12)

An inspection apparatus for detecting a defect in an electrode tab of an electrode assembly, wherein the electrode tab is provided at a longitudinal end of the electrode assembly, the inspection apparatus comprising: a radiation emitting means configured to emit an x-ray or a beta ray towards the electrode tab; a radiation measuring means, disposed opposite the radiation emitting means so as to have the electrode tab positioned therebetween, wherein the radiation measuring means is configured to measure an amount of the x-ray or the beta ray transmitted through the electrode tab; a processor configured to process a signal corresponding to the measured amount of the x-ray or the beta ray and determine a defect if the amount of the x-ray or the beta ray measured at a portion within the electrode tab shows a drop by a predetermined threshold or more, compared to a reference value.
The inspection apparatus of claim 1, wherein the reference value is an average amount of the x-ray or the beta ray measured at neighboring portions within the electrode tab.
The inspection apparatus of claim 1, wherein the reference value is a desired amount of the x-ray or the beta ray preset by a user.
The inspection apparatus of any one of claims 1 to 4, further comprising a controller configured to repeatedly perform the inspection at a plurality of positions within the electrode tab by relatively moving the radiation emitting/measuring means with respect to the electrode tab.
The inspection apparatus of claim 4, wherein the radiation emitting/measuring means are relatively moved with respect to the electrode tab at least in the longitudinal direction of the electrode assembly.
An inspection method for detecting a defect in an electrode tab of an electrode assembly, wherein the electrode tab is provided at a longitudinal end of the electrode assembly, the inspection method comprising: 1) emitting, by a radiation emitting means, an x-ray or a beta ray towards the electrode tab; 2) measuring, by a radiation measuring means, an amount of the x-ray or the beta ray transmitted through the electrode tab; 3) determining a defect if the amount of the x-ray or the beta ray measured at a portion within the electrode tab shows a drop by a predetermined threshold or more, compared to a reference value.
The inspection method of claim 6, wherein the reference value is an average amount of the x-ray or the beta ray measured at neighboring portions within the electrode tab.
The inspection method of claim 6, wherein the reference value is a desired amount of the x-ray or the beta ray preset by a user.
The inspection method of any one of claims 6 to 8, wherein steps 1) and 2) are repeatedly performed at a plurality of positions within the electrode tab by relatively moving the radiation emitting/measuring means with respect to the electrode tab.
The inspection method of claim 9, wherein the radiation emitting/measuring means are relatively moved with respect to the electrode tab at least in the longitudinal direction of the electrode assembly.
The inspection method of any one of claims 6 to 10, wherein the inspection is performed after the electrode tab is formed by welding a plurality of single-layer electrode tabs of respective electrode sheets forming the electrode assembly.
The inspection method of claim 11, wherein the inspection is performed after a lead is welded on the electrode tab.

Description

TECHNICAL FIELD The present invention relates to an inspection apparatus for detecting a defect in an electrode tab of an electrode assembly, and a method for detecting a defect in an electrode tab of an electrode assembly. More particularly, the present invention relates to an inspection apparatus for detecting a defect in an electrode tab of an electrode assembly, as well as a method for detecting a defect in an electrode tap of an electrode assembly, capable of effectively identifying a defective electrode tab and preventing an electrode assembly with the defective electrode tab from being transferred to downstream of the electrode assembly manufacturing process. BACKGROUND Secondary batteries, or often called rechargeable batteries, can be discharged by being used and then restored to their original state by charging. Secondary batteries have recently been widely used as an energy source of wireless devices, such as a personal digital devices, mobile telephone, or notebook computer. Moreover, the secondary battery has attracted attention as an energy source of an electric vehicle, a hybrid electric vehicle, and the like, which are regarded as a solution to the air pollution problem caused by traditional gasoline or diesel vehicles using fossil fuel. Due to the apparent advantages of the secondary battery over other traditional energy sources, the application of secondary battery continuously becomes wider and the consumer's demands for the secondary battery is also increasing. Among various secondary batteries, a lithium secondary battery is particularly widely used as an energy source for various electronic products because the lithium secondary battery shows a high energy density, a high operating voltage, as well as excellent storage and lifetime characteristics. In the meantime, secondary batteries can be also classified depending on the shape of a battery case. For example, they may be classified into cylindrical or prismatic batteries, according to which an electrode assembly is embedded in a cylindrical or prismatic metal can. Furthermore, in case of pouch-type batteries, the electrode assembly is embedded in a pouch-type case of an aluminum laminate sheet. The electrode assembly, embedded in the battery case, functions as a power generating element capable of charging and discharging. The electrode assembly comprises a positive electrode, a negative electrode, and a separator interposed between the positive and the negative electrodes. The electrode assembly can be generally classified into a jelly-roll type and a stack type. In case of the j elly-roll type electrode assembly, a positive electrode and a negative electrode, which are long sheet-shaped and are coated with an active material, are wound along their longitudinal direction, having a separator interposed therebetween. On the other hand, in case of the stack type electrode assembly, a plurality of positive electrodes and negative electrodes of a predetermined size are sequentially stacked on top of the other, having a separator interposed therebetween. Uncoated portions of the stacked electrodes form an electrode tab of the electrode assembly. In the processes of forming the electrode tab of the electrode assembly, however, a defect can occur to the electrode tab. Accordingly, it would be advantageous to develop a technology capable of addressing the above technical problem. SUMMARY OF THE INVENTION It is an objective of the present invention to provide an inspection apparatus/method for detecting a defect in an electrode assembly. The problem is at least partially solved or alleviated by the subject-matter of independent claims, wherein further examples are incorporated in dependent claims. One aspect of the present invention relates to an inspection apparatus for detecting a defect in an electrode tab of an electrode assembly. The electrode tab may be provided at a longitudinal end of the electrode assembly. The inspection apparatus comprises a radiation emitting means configured to emit an x-ray or a beta ray towards the electrode tab and a radiation measuring means, disposed opposite the radiation emitting means so as to have the electrode tab positioned therebetween. The radiation measuring means may be configured to measure an amount of the x-ray or the beta ray transmitted through the electrode tab. The inspection apparatus may further comprise a processor configured to process a signal corresponding to the measured amount of the x-ray or the beta ray and determine a defect if the amount of the x-ray or the beta ray measured at a portion within the electrode tab shows a drop by a predetermined threshold or more, compared to a reference value. The present invention enables effectively identifying a defect in an electrode tab of an electrode assembly at an early stage, specifically as early as the electrode tab is formed through the tab welding process. In addition, it enables the process to be performed in non-destructive way. Acc