JP-7854953-B2 - Method for inspecting electrode plates, method for manufacturing energy storage devices, and apparatus for inspecting electrode plates

JP7854953B2JP 7854953 B2JP7854953 B2JP 7854953B2JP-7854953-B2

Inventors

山崎友道
坂井朋英
巣之内聡裕
谷永朝一

Assignees

プライムプラネットエナジー＆ソリューションズ株式会社
パナソニックプロダクションエンジニアリング株式会社

Dates

Publication Date: 20260507
Application Date: 20230308

Claims (7)

A method for inspecting an electrode plate that has been coated with a coating material containing an active material and rolled into a current collector plate, This includes an inspection to detect the recessed portion of the coating material, The inspection for detecting the aforementioned depression is, The process involves shining a linear beam of light extending in the width direction of the electrode plate obliquely onto the surface of the coating material, and further moving the electrode plate in a longitudinal direction perpendicular to the width direction with respect to the light, The process involves sequentially acquiring the specularly reflected light from the coating material at multiple locations in the longitudinal direction while the electrode plate is transported a predetermined distance in the longitudinal direction , The process involves dividing the acquired specularly reflected light in the width direction, and in each of the multiple regions in the width direction, calculating the average value of the brightness at multiple locations in the longitudinal direction from the brightness data of the specularly reflected light acquired at multiple locations in the longitudinal direction. A step of determining a correction value for each of the multiple regions in the width direction such that the average value of the brightness in those regions is the same, A step of adding the correction value to the brightness of the specularly reflected light in each region in the width direction, The process includes detecting dark areas with lower brightness than a predetermined threshold in the brightness distribution of the specularly reflected light after the correction value has been added, and determining that the detected dark areas are depressions. Method for inspecting electrode plates.
The inspection for detecting the depressions includes a step of determining the electrode plate to be defective if a predetermined number of dark areas of a predetermined size or larger are detected. The method for inspecting electrode plates according to claim 1.
The electrode plate is a negative electrode plate in which a coating material containing a negative electrode active material is coated onto a current collector plate and then rolled. The method for inspecting electrode plates according to claim 1.
A method for manufacturing an energy storage device, comprising a method for inspecting electrode plates according to any one of claims 1 to 3.
A conveying device for transporting electrode plates, which have been coated with a coating material containing an active material and rolled, in the longitudinal direction thereof, An illumination device that irradiates the surface of the coating material on the electrode plate being transported by the transport device with linear light extending in the width direction of the electrode plate at an oblique angle, An acquisition device is positioned on the path of specularly reflected light from the coating material, which is irradiated by the aforementioned lighting device, and sequentially acquires specularly reflected light from multiple locations in the longitudinal direction of the coating material while the electrode plate is transported a predetermined distance in the longitudinal direction . The system includes a determination device for determining the presence or absence of depressions in the coating material, The determination device is A first processing unit divides the specularly reflected light acquired by the acquisition device in the width direction, and in each of the multiple regions in the width direction, calculates the average value of the brightness at multiple locations in the longitudinal direction from the brightness data of the specularly reflected light acquired at multiple locations in the longitudinal direction. A second processing unit that determines a correction value for each of the multiple regions in the width direction such that the average value of the brightness in those regions is the same, A third processing unit that adds the correction value to the brightness of the specularly reflected light in each region in the width direction, The system includes a fourth processing unit that detects dark areas with a brightness lower than a predetermined threshold in the brightness distribution of the specularly reflected light after the correction value has been added, and determines that the detected dark areas are depressions. An inspection device for electrode plates.
The determination device includes a fifth processing unit that determines the electrode plate to be defective when a predetermined number of dark areas of a predetermined size or larger are detected. The electrode plate inspection apparatus according to claim 5.
The electrode plate is a negative electrode plate in which a coating material containing a negative electrode active material is coated onto a current collector plate and then rolled. The electrode plate inspection apparatus according to claim 5.

Description

This invention relates to a method for inspecting electrode plates, a method for manufacturing energy storage devices, and an apparatus for inspecting electrode plates. For example, Patent Document 1 discloses a method for manufacturing a secondary battery, which includes a coating step of forming a layer of active material on a strip-shaped metal foil, a pressing step of increasing the density of the active material layer by applying pressure, and an inspection step of detecting abnormalities in the active material layer. The inspection step disclosed in Patent Document 1 detects abnormalities such as abnormalities in the thickness of the active material layer, scratches on the active material layer, and foreign matter mixed in. Furthermore, for example, Patent Document 2 discloses a lithium deposition inspection device for detecting lithium deposited on the surface of the negative electrode composite layer of a lithium-ion secondary battery. The inspection device disclosed in Patent Document 2 detects deposited lithium by irradiating the negative electrode composite layer with white light and acquiring image data of the reflected light. The inspection device acquires the image data in RGB format and converts the information of each pixel in the image data into hue angle and brightness. The inspection device disclosed in Patent Document 2 determines whether there are pixels exhibiting a hue angle and brightness characteristic of lithium deposition. Japanese Patent Publication No. 2017-069131Japanese Patent Publication No. 2021-021579 This is a schematic side view of an electrode plate inspection device.This is a schematic diagram of an image taken near the sinkhole.This is a flowchart showing the inspection process for electrode plates.This graph shows an example of the brightness distribution of specularly reflected light.This is a graph of average brightness, illustrating an example of how correction values are calculated.This graph shows the brightness distribution of specularly reflected light after correction. The following describes one embodiment of the electrode plate inspection device. It should be noted that the embodiment described here is not intended to limit the present invention. Furthermore, the figures are schematic diagrams and do not necessarily faithfully reflect actual implementations. In the following, components and parts that perform the same function are denoted by the same reference numerals, and redundant explanations are omitted or simplified as appropriate. [Configuration of the electrode plate inspection device] Figure 1 is a schematic side view of the electrode plate inspection device 10. The electrode plate 1 to be inspected by the electrode plate inspection device 10 is an electrode plate of an energy storage device, such as a lithium-ion secondary battery. In this specification, "energy storage device" is a term that refers to all devices that can be repeatedly charged and discharged, and is a concept that includes chemical batteries such as lithium-ion secondary batteries and nickel-metal hydride batteries, and physical batteries such as electric double-layer capacitors. As shown in Figure 1, the electrode plate 1 is formed in a strip shape by coating a current collector plate 2 with a coating material 3 containing an active material. The electrode plate inspection device 10 inspects whether there are any depressions 5 (see Figure 2) on the surface of the coating material 3. A depression 5 is a defect that is recessed compared to the surrounding normal portion 4 (see Figure 2). The electrode plate inspection device 10 performs the inspection for depressions 5 on the electrode plate 1 after the coating material 3 has been applied to the current collector plate 2 and rolled (after the pressing process). In this embodiment, the electrode plate inspection device 10 inspects the negative electrode plate 1, which is coated with a coating material 3 containing the negative electrode active material onto the negative electrode current collector plate 2. Positive ions tend to precipitate at defects in the coating material 3 on the negative electrode plate 1. Therefore, inspection of indentations 5 on the negative electrode plate 1 is more important than inspection of the positive electrode plate. However, the electrode plate inspection device 10 may also be used to inspect for the presence or absence of indentations on the positive electrode plate. As shown in Figure 1, the electrode plate inspection device 10 comprises a transport device 20, an illumination device 30, a reflected light acquisition device 40, and a determination device 50 for determining the presence or absence of a recessed portion 5 (see Figure 2). The conveying device 20 conveys the electrode plate 1 in its longitudinal direction. The longitudinal direction of the electrode plate 1 is perpendicular to the width direction of the electrode plate 1. As shown in Figure 1, the conveying device 20 is equipped with co