JP2008153119A - Battery inspection system, and battery inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To determine what level of thickness an electrolyte located on a surface of a battery has. <P>SOLUTION: An imaging device 3 receiving reflected light of a far-infrared ray emitted to an inspection object surface 10a of the battery 10 from a planar light source 1 is structured to selectively receive only a light having a wavelength in the band of 7-12 μm. Hence, light of a quantity (intensity), in response to the thickness of the electrolyte located on the inspection object surface 10a of the battery 10, can be received by the imaging device 3, and information related to the thickness of the electrolyte can be included in a signal of the image imaged by the imaging device 3. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a battery inspection system and a battery inspection method, and is particularly suitable for inspecting the presence or absence of leakage of an electrolyte solution inside a battery.

Conventionally, a battery containing an electrolytic solution is inspected whether or not the electrolytic solution leaks to the surface, and is shipped after confirming that the electrolytic solution does not leak to the surface. As a technique for inspecting the presence or absence of leakage of the electrolyte solution in the battery, there is a technique described in Patent Document 1.
In the technique described in Patent Document 1, first, of the reflected light from the battery, the wave number (1.820 [cm ⁻¹ ] to 1.650 [cm ⁻¹ ]), that is, the wavelength (which is well absorbed by the electrolyte solution) 5. A measurement image is generated by receiving infrared light of 5.49 [μm] to 6.06 [μm]), and a comparative image is generated by receiving infrared light having a wavelength that is not so much absorbed by the electrolyte. Then, the measurement image and the comparison image are compared to determine whether or not the electrolyte is leaking from the inside of the battery.

Japanese Patent No. 3789696

  By the way, when the battery is filled with the electrolytic solution (in the charge liquid filling step), the electrolytic solution may slightly adhere to the surface of the battery. Since the thickness of such an electrolyte is generally thin and is not necessarily a malfunction, it must be distinguished from an electrolyte that leaks from the inside and adheres to the surface of the battery.

  However, in the above-described conventional technique, infrared light having a wavelength that is well absorbed by the electrolytic solution is received and a measurement image is generated. Therefore, the thickness of the electrolytic solution adhering to the surface of the battery is shallow. Whether it is deep or deep, the electrolyte is clearly captured in the same way. Therefore, there is a problem that it is difficult to determine how thick the electrolytic solution adhering to the surface of the battery has.

  The present invention has been made in view of such problems, and it is possible to determine whether or not there is leakage of the electrolyte in consideration of the thickness of the electrolyte on the surface of the battery. The purpose is to do so.

  The battery inspection system according to the present invention includes a planar light source that irradiates a far-infrared ray to the inspection target surface of the battery, and the far-infrared ray that is irradiated to the inspection target surface of the battery by the planar light source. Receiving means for receiving and acquiring the reflected light reflected from the surface to be inspected of the battery, and determining means for determining whether the battery is abnormal based on the reflected light acquired by the acquiring means The acquisition means has a wavelength in a predetermined range including a wavelength at which the round-trip transmittance is 0.8 or more when the thickness of the electrolyte attached to the surface to be inspected of the battery is 0.5 [μm]. The light is selected and acquired from the reflected light.

  In the battery inspection method of the present invention, an irradiation step of irradiating a far-infrared ray from a planar light source to the inspection target surface of the battery, and a far-infrared ray being irradiated by the irradiation step, the inspection target surface of the battery An acquisition step of receiving and acquiring reflected reflected light, and a determination step of determining whether or not the battery is abnormal based on the reflected light acquired by the acquisition step, the acquisition step, Light having a wavelength in a predetermined range including a wavelength at which the round-trip transmittance is 0.8 or more when the thickness of the electrolytic solution adhering to the surface to be inspected of the battery is 0.5 [μm] is reflected from the reflected light. It is characterized by selecting and acquiring.

  According to the present invention, light having a wavelength in a predetermined range including a wavelength at which the round-trip transmittance is 0.8 or more when the thickness of the electrolyte attached to the surface to be inspected of the battery is 1 [μm] is selected. Therefore, information on the thickness of the electrolytic solution can be included in the image signal based on the received light. Therefore, it becomes possible to determine how thick the electrolytic solution adhering to the inspection target surface of the battery has.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing an example of a schematic configuration of the battery inspection system of the present embodiment.
In FIG. 1, the battery inspection system of the present embodiment includes a planar light source 1, a temperature control device 2, an imaging device 3, a PC (Personal Computer) 4, a defective product discharge mechanism 5, and a heating device 6. Have.

First, an example of the inspection flow of the battery 10 in the battery inspection system of this embodiment will be described.
The battery 10 to be inspected is heated by the heating device 6 and then placed on, for example, a belt conveyor (not shown). When the battery 10 placed on the belt conveyor moves to a predetermined inspection area, far-infrared rays are irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10. Then, an image signal based on the reflected light reflected by the inspection target surface 10 a of the battery 10 is imaged by the imaging device 3. The PC 4 determines whether or not the battery 10 is a non-defective product based on the image signal captured by the imaging device 3. When the inspection is completed, the battery 10 flows in a normal path and is passed to a subsequent process if it is a non-defective product. On the other hand, if it is a defective product, the defective product discharge mechanism 5 discharges it to a route different from the regular route.

  Next, the configuration of the battery inspection system of this embodiment will be described. In the present embodiment, the battery 10 to be inspected is a secondary battery (such as a lithium ion secondary battery) having a width of 100 [mm], a depth of 100 [mm], and a height of 10 [mm]. A case will be described as an example. Further, in the present embodiment, a case where the upper surface (cover surface) of the battery 10 is the inspection target surface 10a will be described as an example.

The heating device 6 heats the battery 10 to be inspected to a predetermined temperature and gives a pressure difference between the inside and the outside of the battery 10, thereby leaking the electrolyte solution inside the battery 10. In order to promote the leakage of the electrolyte.
The planar light source 1 is for irradiating far-infrared rays onto the inspection target surface 10 a of the battery 10. The planar light source 1 of the present embodiment includes a black body radiating unit that irradiates far infrared rays from a square (planar) irradiation surface having a length of 200 [mm] and a width of 200 [mm], for example. The black body radiating portion has, for example, a brass whose surface is blackened and a heating wire provided inside the brass. The heating wire is disposed inside the brass so that substantially uniform heat is applied to the entire square (planar) irradiation surface.

  The temperature control device 2 is for controlling the temperature of the planar light source 1 based on a far infrared irradiation instruction signal from the PC 4. The temperature control device 2 of the present embodiment controls the temperature of the planar light source 1 by controlling the current flowing through the heating wire embedded in the blackened brass. When the temperature of the irradiation surface of the planar light source 1 rises to a temperature at which far-infrared rays are irradiated (for example, 50 [° C.]) by the control of the temperature control device 2, the square (planar) shape of the planar light source 1 is increased. Far infrared rays are emitted from the irradiated surface. In this embodiment, the planar light source 1 emits far infrared rays having a wavelength of 3 [μm] or more and 70 [μm] or less when the surface temperature is 50 [° C.].

  The imaging device 3 detects reflected light reflected by the inspection target surface 10a of the battery 10 by irradiating the inspection target surface 10a of the battery 10 from the planar light source 1, and converts the detected reflected light into the detected reflected light. Based on this, it is a means for acquiring an image signal of the inspection target surface 10a of the battery 10. That is, the imaging device 3 is for capturing an image signal based on the amount of reflected light (the amount of reflected light) of the inspection target surface 10 a irradiated with far infrared rays from the planar light source 1. Specifically, the imaging device 3 is a far-infrared camera, for example. Thus, in the present embodiment, for example, an acquisition unit (acquisition unit) is configured using the imaging device 3.

The imaging device 3 of the present embodiment selects only light having a wavelength in a band of 7 [μm] or more and 12 [μm] or less from the reflected light reflected by the inspection target surface 10 a by the imaging lens of the imaging device 3. I try to get it. Here, with reference to FIG. 2 and FIG. 3, the reason for selectively acquiring only light having such a wavelength band will be described.
FIG. 2 is a diagram showing an example of an absorption curve showing the relationship between the far-infrared absorptance and the wavelength in the electrolytic solution in the battery 10.

  As shown in FIG. 2, in the example described in the present embodiment, the electrolytic solution in the battery 10 absorbs light having a wavelength of 5.7 [μm] best. Therefore, as in the prior art, when only the light having a wavelength in the vicinity of 5.7 [μm] that absorbs the electrolyte well is received by the imaging device 3, Whether the thickness is shallow or deep, the image signal has the same density (luminance).

By the way, for the sake of explanation, it is assumed that the round-trip transmittance T when light passes through a medium (electrolytic solution) having a thickness of d [μm] is expressed by the following equation (1).
T = 10 ^−Abs · 2 ^d (1)
Here, Abs [1 / μm] is an absorption coefficient. In the case where only light having a wavelength range with extremely high absorption rate (for example, light having a wavelength of 5.7 [μm]) is used, the absorption is determined according to the infrared absorption spectrum analysis of the electrolyte solution of the lithium ion secondary battery. The coefficient Abs is about 1.3. Therefore, even in an electrolytic solution having a film thickness d of 0.5 [μm], the round-trip transmittance T of light of the wavelength is about 0.05, and the light of the wavelength is significantly attenuated (absorbed by the electrolytic solution). ) Even if the electrolytic solution has a thickness of only 1 [μm], the round-trip transmittance T is 0.0025 (= (0.05) ² ), and the light is almost completely absorbed by the electrolytic solution. If an image obtained by detecting reflected light with the imaging device 3 is converted into an 8-bit luminance signal by 8 bits (256 gradations) and a grayscale image signal is generated, the thickness of the electrolytic solution is discriminated. Capability cannot be given to the imaging device 3 or the PC 4.

  Therefore, in the present embodiment, the imaging device 3 adheres to the surface of the battery 10 so that a very small amount of the electrolyte that is not leaked from the electrolyte and an amount of the electrolyte that is apparently caused by the leak can be distinguished. The imaging device 3 selectively acquires light having a wavelength that allows the electrolyte solution to pass to some extent. That is, in order to be able to discriminate with a gray scale image up to at least 50 [μm] with respect to the thickness of the electrolytic solution, for example, the absorption coefficient Abs is 0.03 or less (the thickness d of the electrolytic solution is 0.5 [μm]). At this time, light having a wide wavelength band in which the round-trip transmittance T is about 0.933 (93.3 [%]) or more) is selected and acquired. More specifically, in the present embodiment, the band is wider than the width of the portion having the peak showing the maximum value at the wavelength of 5.7 [μm], and there are a plurality of peaks excluding the peak. Light having a wavelength in a certain band is selectively acquired by the imaging lens of the imaging device 3. In this embodiment, as an example of such a band, a band of 7 [μm] or more and 12 [μm] or less is set as described above. By selecting and acquiring the reflected light in this way, a gray scale image signal corresponding to the thickness of the electrolytic solution can be detected.

FIG. 3 is a diagram illustrating an example of a state in which far infrared rays irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10 are reflected by the inspection target surface 10a.
As described above, in the present embodiment, the imaging device 3 uses only the light having a wavelength of 7 [μm] or more and 12 [μm] or less among the reflected light from the inspection target surface 10a of the battery 10. I'm trying to get it selectively. The band of 7 [μm] or more and 12 [μm] or less is a band where a plurality of continuous peaks exist in the absorption curve 21 shown in FIG. Therefore, as shown in FIG. 3, a part of the light 31a having a wavelength of 7 [μm] or more and 12 [μm] or less among the far infrared rays irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10 is Although absorbed by the electrolytic solution 32, the remaining part permeates through the electrolytic solution 32 while being attenuated according to the thickness of the electrolytic solution 32. Since the light transmitted through the electrolytic solution 32 is reflected by the inspection target surface 10a of the battery 10, it is irradiated outside the electrolytic solution 32 as reflected light 31b. Here, the light (far infrared rays) having a wavelength of 7 [μm] or more and 12 [μm] or less has a long wavelength, and therefore has a high reflectance on the inspection target surface (metal surface) 10a of the battery 10. Furthermore, the light (far infrared rays) having such a long wavelength reflects the inspection target surface 10a of the battery 10 without being affected by the roughness of the inspection target surface 10a of the battery 10 as much as possible.

  As described above, part of the light 31 a having a wavelength of 7 [μm] or more and 12 [μm] or less among the far infrared rays irradiated from the planar light source 1 to the inspection target surface 10 a of the battery 10 is the electrolytic solution 32. The imaging device 3 has a wavelength of 7 [μm] or more and 12 [μm] or less because it passes through the electrolytic solution 32 while being attenuated according to the thickness of the battery 10 and is well reflected by the inspection target surface 10a of the battery 10. By selectively acquiring light, an amount (intensity) of light corresponding to the thickness of the electrolytic solution 32 can be selected and received as reliably as possible. Therefore, information regarding the thickness of the electrolytic solution 32 can be included in the image signal captured by the imaging device 3. Therefore, more information can be obtained than in the conventional technique in which light having substantially the same intensity is received regardless of the thickness of the electrolytic solution 32.

Next, a method for determining the size of the irradiation surface of the planar light source 1 and a method for determining the arrangement of the planar light source 1, the imaging device 3, and the battery 10 will be described with reference to FIG.
FIG. 4 is a diagram illustrating an example of the arrangement relationship between the planar light source 1, the imaging device 3, and the battery 10.
4A shows an optical path of specularly reflected light 41b that is regularly reflected by the inspection target surface 10a of the battery 10 by irradiating the inspection target surface 10a of the battery 10 from the planar light source 1 with the far infrared ray 41a. It is the figure which showed an example. FIG. 4B shows a dent portion (unevenness) formed on the inspection target surface 10 a of the battery 10 by irradiating the far-infrared ray 41 a from the planar light source 1 to the inspection target surface 10 a of the battery 10. (Part) It is the figure which showed an example of the optical path of the reflected light 41c reflected by 10b.

  As shown in FIG. 4A, in the present embodiment, the planar light source 1 and the imaging device are configured so that the light receiving surface (imaging lens) of the imaging device 3 is completely included in the irradiation region of the regular reflection light 41b. The apparatus 3 and the battery 10 are arranged, and as shown in FIG. 4B, a part or all of the irradiation area of the reflected light 41c is not included in the light receiving surface (imaging lens) of the imaging apparatus 3. The planar light source 1, the imaging device 3, and the battery 10 are arranged. As described above, the amount of light received by the imaging device 3 of the reflected light 41c reflected by the dent portion (uneven portion) 10b formed on the inspection target surface 10a of the battery 10 is changed to the amount of light received by the regular reflected light 41b. Can be made smaller.

  Specifically, in the present embodiment, the minimum value of the size (area and depth) of the dent portion (uneven portion) 10b to be detected as a defect is determined. Then, by irradiating the far-infrared ray 41a to the dent portion 10b having the minimum value, the received light amount of the reflected light 41c received by the imaging device 3 is a predetermined value than the received light amount of the regular reflected light 41b. The planar light source 1, the imaging device 3, and the battery 10 are arranged so as to be smaller. By doing so, it is possible to reliably detect a dent portion (uneven portion) having a predetermined size that is desired to be detected as a defect based on the amount of the reflected light 41c received by the imaging device 3.

  In addition, in this embodiment, the inspection target surface 10a of the battery 10 is completely included in the irradiation region of the far infrared ray 41a irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10. The planar light source 1, the imaging device 3, and the battery 10 are arranged. This is because the far-infrared rays 41a that are as uniform as possible are irradiated to the entire inspection target surface 10a of the battery 10.

As described above, in the present embodiment, the size of the irradiation surface of the planar light source 1 is determined so as to satisfy both of the following (A) and (B), and the planar light source 1 and the imaging device 3 are determined. , And the arrangement of the battery 10 is determined.
(A) The reflected light reflected by the dent portion (uneven portion) 10b of the inspection target surface 10a of the battery 10 by irradiating the inspection target surface 10a of the battery 10 from the planar light source 1 with the far infrared ray 41a. The amount of received light in the imaging device 3 of 41c is made smaller than the amount of received light of the regular reflection light 41b.
(B) The inspection target surface 10a of the battery 10 is completely included in the irradiation region of the far infrared ray 41a irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10.
Note that the far-infrared irradiation from the planar light source 1 and the imaging by the imaging device 3 are preferably performed immediately after the battery 10 is heated by the heating device 6. This is because immediately after the battery 10 is heated, the leakage of the electrolyte in the battery 10 becomes significant.

  Returning to FIG. 1, the PC 4 has a computer main body 4a, a user interface 4b, and a display 4c. The computer main body 4a includes a CPU, a ROM, a RAM, a hard disk, and the like. A battery inspection application program for inspecting the battery 10 as described later is installed in the hard disk of the computer main body 4a. The user interface 4b includes a keyboard and a mouse. Further, the display 4c is a so-called computer display, and includes, for example, an LCD (Liquid Crystal Display).

Specifically, the CPU executes, for example, the following process by executing a battery inspection application program stored in the hard disk.
First, the CPU generates an irradiation instruction signal for causing the planar light source 1 to irradiate far infrared rays, and transmits the irradiation instruction signal to the temperature control device 2. Based on this irradiation instruction signal, the temperature control device 2 raises the temperature of the planar light source 1 and irradiates far-infrared rays from the planar light source 1 to the inspection target surface 10 a of the battery 10.

Thereafter, when the image signal of the inspection target surface 10a of the battery 10 is captured by the imaging device 3, the CPU acquires the image signal, and the inspection target surface 10a of the battery 10 is preliminarily applied to the inspection target surface 10a based on the acquired image signal. It is simultaneously determined whether or not there is a dent portion (uneven portion) having a predetermined size or more and whether or not the electrolyte leaks from the inside of the battery 10 to the inspection target surface 10a. It is determined whether or not there is. And CPU produces | generates the image signal which shows the result of the determination, and displays it on the display 4c. Further, when the battery 10 is not a non-defective product, the CPU transmits a battery discharge instruction signal to the defective product discharge mechanism 5.
A detailed description of functions realized by the CPU executing the battery inspection application program stored in the hard disk as described above will be described later with reference to FIG.

  The defective product discharge mechanism 5 is, for example, for discharging the battery 10 conveyed on a belt conveyor (not shown) to a route different from the normal route based on the battery discharge instruction signal transmitted from the PC 4. is there.

  FIG. 5 is a block diagram illustrating an example of a functional configuration of the computer main body 4a provided in the battery inspection system. Each unit in the computer main body 4a shown in FIG. 5 can be realized by a CPU provided in the computer main body 4a executing, for example, a battery inspection application program stored in a hard disk.

For example, when the user operates the user interface 4 b to issue a far infrared irradiation instruction, the irradiation instruction unit 51 generates a far infrared irradiation instruction signal and transmits the far infrared irradiation instruction signal to the temperature control device 2. Thereby, the temperature control device 2 controls the temperature of the planar light source 1 and irradiates far-infrared rays from the planar light source 1 to the inspection target surface 10 a of the battery 10.
For example, after the far-infrared irradiation instruction signal is transmitted from the irradiation instruction unit 51 to the temperature control device 2, the imaging instruction unit 52 generates an imaging instruction signal and transmits it to the imaging device 3. Thereby, the imaging device 3 captures an image signal of the inspection target surface 10a of the battery 10 irradiated with far infrared rays from the planar light source 1.

The image signal acquisition unit 53 inputs an image signal picked up by the image pickup device 3 and temporarily stores the acquired image signal in a RAM or the like for acquisition.
The image signal blunting unit 54 performs a broadband low-pass filtering process on the image signal acquired by the image signal acquiring unit 53. Thereby, only the signal of the predetermined | prescribed low frequency component which passed the broadband digital low pass filter among the image signals acquired by the image signal acquisition part 53 is extracted.

The difference processing unit 55 generates a difference image signal between the image signal acquired by the image signal acquisition unit 53 and the image signal that has passed through the image signal blunting unit (broadband digital low-pass filter) 54. As a result, a signal (a predetermined low-frequency component signal) in a region where the density (luminance) change is gradual is removed from the image signal acquired by the image signal acquisition unit 53.
The binarization unit 56 binarizes the value of each pixel of the difference image signal generated by the difference processing unit 55 to generate a binarized image signal. Specifically, the binarization unit 56 has the density value when the density value (luminance value) of each pixel of the difference image signal generated by the difference processing unit 55 is greater than or equal to a preset threshold value. A pixel is set to “1”, and if it is less than a preset threshold, a pixel having that density value is set to “0”.

The labeling unit 57 performs a labeling process on the binarized image signal generated by the binarizing unit 56 to generate a label image signal. As a result, the same label number is given as the pixel value to each pixel in the region where “1” is set continuously.
The density peak value deriving unit 58 uses the difference processing unit 55 to calculate the density value of the highest density pixel (hereinafter referred to as the density peak value) among the plurality of pixels assigned the same label number by the labeling unit 57. Calculation is performed with reference to the density value of each pixel of the generated difference image signal. The density peak value deriving unit 58 calculates a density peak value for each region composed of pixels to which the labeling unit 57 has been given the same label number.

  The density integrated value deriving unit 59 uses the integrated value of the density of each pixel (hereinafter referred to as the density integrated value) to which the same label number is given by the labeling unit 57 as the difference image signal generated by the difference processing unit 55. Calculation is performed with reference to the density value of each pixel. For example, the density integral value deriving unit 59 calculates a function indicating the relationship between the density value of each pixel of the difference image signal generated by the difference processing unit 55 and the position of each pixel within the range where each pixel exists. Integrate to calculate the integrated density value. The integrated density value deriving unit 59 calculates the integrated density value for each region including pixels to which the labeling unit 57 is assigned the same label number.

  The area deriving unit 60 binarizes the area value (hereinafter, simply referred to as area value) of the region made up of the pixels assigned the same label number by the labeling unit 57 and generated by the binarizing unit 56. Calculation is performed with reference to the image signal. The density peak value deriving unit 58 calculates an area value for each region including pixels to which the labeling unit 57 has been assigned the same label number.

  The non-defective product determination unit 61 determines whether the concentration peak value calculated by the concentration peak value deriving unit 58 is equal to or greater than a predetermined first threshold and whether the concentration integrated value calculated by the concentration integrated value deriving unit 59 is a predetermined value. The labeling unit 57 gives the same label number as to whether or not the second threshold value is equal to or greater than the second threshold value and whether the area value calculated by the area deriving unit 60 is equal to or greater than the predetermined third threshold value. A determination is made for each area composed of pixels. As a result of this determination, at least one of the concentration peak value, the concentration integrated value, and the area value calculated by the concentration peak value deriving unit 58, the concentration integrated value deriving unit 59, and the area deriving unit 60 is greater than or equal to the threshold value. If there is, the non-defective product determination unit 61 determines that the battery 10 is defective. Then, the non-defective product determination unit 61 generates a battery discharge instruction signal and transmits it to the defective product discharge mechanism 5. Thereby, the defective product discharge mechanism 5 discharges the battery 10 carried on a belt conveyor (not shown) to a path different from the normal path, for example.

  On the other hand, if the concentration peak value, the integrated concentration value, and the area value calculated by the concentration peak value deriving unit 58, the concentration integrated value deriving unit 59, and the area deriving unit 60 are smaller than the threshold value in all the regions, the non-defective product determination is performed. The unit 61 determines that the battery 10 is a good product. In this case, the battery 10 carried on a belt conveyor (not shown) passes through a regular route and is passed to a subsequent process.

In addition, the non-defective product determination unit 61 generates an image signal indicating the determination result as described above and transmits the image signal to the display 4c. Thereby, the display 4c displays an image indicating whether or not the battery 10 is a non-defective product.
As described above, in the present embodiment, for example, the image signal acquisition unit 53, the image signal blunting unit 54, the difference processing unit 55, the binarization unit 56, the labeling unit 57, the density peak value deriving unit 58, and the density integral value deriving unit. 59, the area deriving unit 60, and the non-defective product determining unit 61 constitute a determining unit 50 (determining means).

  The heating instruction unit 62 generates a heating instruction signal based on, for example, an operation of the user interface 4b by the user, and transmits the heating instruction signal to the heating device 6. Thereby, the heating device 6 heats the battery 10, and when a pressure difference is given between the inside and the outside of the battery 10, and the electrolyte solution in the battery 10 leaks, the electrolyte solution Leakage is promoted.

Next, an example of the processing operation of the battery inspection system will be described with reference to the flowchart of FIG. Here, the description will be made on the assumption that the battery 10 has already been heated by the heating device 6.
First, in step S1, the irradiation instructing unit 51 stands by until an operation of the user interface 4b for irradiating far infrared rays is performed by the user. When the user operates the user interface 4b for irradiating far infrared rays, the process proceeds to step S2. In step S <b> 2, the irradiation instruction unit 51 generates a far infrared irradiation instruction signal and transmits it to the temperature control device 2. Thereby, the planar light source 1 irradiates far-infrared rays to the inspection target surface 10 a of the battery 10 based on the control of the temperature control device 2.

Next, in step S <b> 3, the imaging instruction unit 52 generates an imaging instruction signal and transmits it to the imaging device 3. At this time, the imaging instruction unit 52 confirms that the battery 10 is in a predetermined inspection area, generates an imaging instruction signal, and transmits the imaging instruction signal to the imaging device 3.
Next, in step S <b> 4, the image signal acquisition unit 53 stands by until an image signal captured by the imaging device 3 is input. When the image signal imaged by the imaging device 3 is input, the process proceeds to step S5. In step S5, the image signal acquisition unit 53 temporarily stores the input image signal in a RAM or the like.

  Next, in step S6, the image signal blunting unit 54 performs a wideband low-pass filtering process on the image signal temporarily stored in step S5, and the image signal temporarily stored in step S5. Among them, only the signal of a predetermined low frequency component is extracted, and the image signal is blunted.

Next, in step S7, the difference processing unit 55 generates a difference image signal between the image signal temporarily stored in step S5 and the image signal from which only the signal of the predetermined low frequency component is extracted in step S6. And temporarily stored in a RAM or the like.
Next, in step S8, the binarization unit 56 binarizes the density value (luminance value) of each pixel of the difference image signal generated in step S7 to generate a binarized image signal, which is stored in the RAM or the like. Memorize temporarily. Thereby, “1” or “0” is set for each pixel of the difference image signal generated in step S7.

Next, in step S9, the labeling unit 57 performs a labeling process on the binarized image signal generated in step S8, generates a label image signal, and temporarily stores it in a RAM or the like. As a result, the same label number is given as the pixel value to each pixel in the region where “1” is set continuously.
Next, in step S10, the density peak value deriving unit 58 refers to the density value of each pixel of the difference image signal generated in step S8, and from the plurality of pixels given the same label number in step S9. A concentration peak value is obtained for each region.

Next, in step S11, the density integral value deriving unit 59 refers to the density value of each pixel of the difference image signal generated in step S8, and from the plurality of pixels assigned the same label number in step S9. The integrated density value is calculated for each area.
Next, in step S12, the area deriving unit 60 refers to the binarized image signal generated in step S8, and determines the area for each region composed of a plurality of pixels assigned the same label number in step S9. Calculate the value.

Next, in step S13, the non-defective product determination unit 61 determines whether the concentration peak value, concentration integrated value, and area value calculated in steps S10 to S12 are greater than or equal to the first to third threshold values. In S9, the determination is made for each region composed of pixels to which the same label number is given. As a result of this determination, if at least one of the concentration peak value, concentration integrated value, and area value calculated in steps S10 to S12 is equal to or greater than the threshold value, it is determined that the battery 10 is a defective product, which will be described later. The process proceeds to step S16.
On the other hand, if the concentration peak value, concentration integrated value, and area value calculated in steps S10 to S12 are smaller than the threshold value in all regions, the battery 10 is determined to be non-defective, and the process proceeds to step S14.

In step S14, the non-defective product determination unit 61 generates an image signal indicating the determination result (inspection result) in step S13 and transmits the image signal to the display 4c. Thereby, the display 4c displays an image indicating that the battery 10 is a non-defective product.
Next, in step S15, the non-defective product determination unit 61 determines whether or not to end the inspection of the battery 10 based on the operation of the user interface 4b by the user. As a result of the determination, when the inspection of the battery 10 is finished, the far infrared irradiation operation from the planar light source 1, the imaging operation in the imaging device 3, the heating operation in the heating device 6, etc. are finished and the processing is finished. .

On the other hand, when the inspection of the battery 10 is not completed, the process returns to step S3 and the next battery 10 is inspected.
If it is determined in step S13 that the battery 10 is defective, the process proceeds to step S16. In step S <b> 16, the non-defective product determination unit 61 generates a battery discharge instruction signal and transmits it to the defective product discharge mechanism 5. Thereby, the defective product discharge mechanism 5 discharges the battery 10 carried on a belt conveyor (not shown) to a path different from the normal path, for example.
Next, in step S17, the non-defective product determination unit 61 generates an image signal indicating the determination result (inspection result) in step S13, and transmits the image signal to the display 4c. Thereby, the display 4c displays an image indicating that the battery 10 is defective. And it progresses to step S15 mentioned above and it is determined whether an inspection is complete | finished.

  FIG. 7 determines the size of the planar light source 1 and the arrangement of the planar light source 1, the imaging device 3, and the battery 10 when detecting the dent portion 10 b formed on the inspection target surface 10 a of the battery 10. It is a figure explaining the specific example of a method. Here, a case where an inverted conical dent 10b having a radius rd [mm] and a depth hd [mm] is detected will be described as an example.

  In FIG. 7A, a center axis 71 connecting the center of the irradiation surface of the planar light source 1 and the position Q of the inspection target surface 10a of the battery 10 and the center (focal point) of the light receiving surface (imaging surface) of the imaging device 3. ) And the center axis 72 that connects the position Q of the inspection target surface 10a of the battery 10 so as to be an axis target with respect to the axis extending from the position Q in the vertical direction in FIG. 2), the planar light source 1, the imaging device 3, and the battery 10 are arranged.

Then, when the inspection target surface 10a of the battery 10 is regarded as a mirror, the size of the irradiation surface of the planar light source 1 is such that the entire surface of the mirror is completely filled with the irradiation surface of the planar light source 1. To decide. That is, the irradiation of the planar light source 1 so that the inspection target surface 10a of the battery 10 is completely included in the irradiation region of the far infrared ray irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10. Determine the size of the face. Otherwise, the brightness of the image signal captured by the imaging device 3 will be dark at the portion representing the end of the battery 10. Specifically, the size of the irradiation surface of the planar light source 1 can be determined by the appropriate magnification K indicating the size of the planar light source 1 with respect to the size of the inspection target surface 10a of the battery 10. The appropriate magnification K is expressed by the following equation (2).
K = (Lb-h + Lc-b) / Lc-b (2)

  Here, Lb-h is a distance [mm] between the center of the irradiation surface of the planar light source 1 and the position Q of the inspection target surface 10 a of the battery 10. Lc-b is a distance [mm] between the center of the light receiving surface (imaging surface) of the imaging device 3 and the position Q of the inspection target surface 10a of the battery 10. Here, if the distances Lb-h and Lc-b are equal, the appropriate magnification K is 2 (K = 2). Therefore, the irradiation surface of the planar light source 1 needs to have a size (area) twice or more that of the inspection target surface 10 a of the battery 10.

  However, if the irradiation surface of the planar light source 1 is made too large, the amount of received light in the imaging device 3 will not change much depending on the presence or absence of the dent portion 10b. If it does so, the detection sensitivity of the dent 10b which arose on the test object surface 10a of the battery 10 will fall remarkably. Therefore, it is preferable that the appropriate magnification K is not so large (as small as possible) as long as the entire inspection target surface 10a of the battery 10 is completely filled with the irradiation surface of the planar light source 1.

  Next, conditions for adjusting the detection sensitivity of the dent portion 10b generated on the inspection target surface 10a of the battery 10 will be described. As described above, here, a case will be described in which an inverted conical dent 10b having a radius of rd [mm] and a depth of hd [mm] is generated on the inspection target surface 10a of the battery 10 (FIG. 7). (B)). Further, it is assumed that the position Q shown in FIG. 7A has moved to the position P shown in FIG.

As shown in FIG. 7B, the angle formed between the inspection target surface 10a (horizontal plane) of the battery 10 and the inclined surface of the dent portion 10b (the inclination angle from the surface of the inclined surface of the dent portion 10b) is θb. Let it be [rad]. Then, the line of sight connecting the focal point of the imaging device 3 and the position P in the dent portion 10b is deflected by ± 2θb [rad] with respect to the regular reflection angle θ [rad]. If the irradiation surface of the planar light source 1 does not exist in the deflected field of view, a black image signal is imaged by the imaging device 3 as an image signal at the position P. Therefore, if the angle Δθ [rad] represented by the following expression (3) is set larger than 2θb [rad], the amount of received light in the imaging device 3 can be reliably varied depending on the presence or absence of the dent portion 10b. .
Δθ ≒ ATAN (Wh / (2 × Lb-h)) (3)
Here, Wh is the width [mm] of the planar light source 1.

For example, if an infrared lens having a focal length of 50 [mm] is attached to the imaging device 3 and the distances Lb-h and Lc-b are set to 700 [mm], the inclination angle θb of the dent portion 10b is It is about 0.07 [rad] (θb≈0.07 [rad]). Therefore, if the inclination angle θb is a dent portion larger than 0.07 [rad], the presence or absence of the dent portion can be detected with high sensitivity (an image having a clear contrast between the dent portion and the portion other than the dent portion. Signal). And in the dent part 10b shown in FIG.7 (b), the depth hd [mm] of the dent part 10b is computable by the following (4) Formula.
hd = rd × θb (4)
For example, when the radius rd of the dent portion 10b is 1.5 [mm], the depth hd of the dent portion 10b is 0.1 [mm], and very sensitive dent detection in submillimeter units is possible. It becomes.

  If the distance Lb-h is increased from the above-described equation (3), it becomes possible to detect the dent portion 10b with higher sensitivity, but the appropriate magnification K shown by the equation (2) does not become too large. It is necessary to. Therefore, when the size of the irradiation surface of the planar light source 1 is not changed, the planar light source 1 is separated from the battery 10 and the imaging device 3 is also separated from the battery 10 to increase the distance Lc-b and to have a resolution as much as possible. It is preferable to provide the imaging device 3 with a lens having a long focal length so that the inspection target surface 10a of the battery 10 can be reflected in the entire field of view of the imaging device 3 so as not to lower the image.

  As described above, in the present embodiment, the far-infrared rays are irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10, so that 7 [μm] of the reflected light irradiated on the inspection target surface 10a. Only light having a wavelength in the band of 12 [μm] or less is selectively acquired by the imaging lens of the imaging device 3. Therefore, the image pickup device 3 can receive an amount (intensity) of light corresponding to the thickness of the electrolyte attached to the inspection target surface 10a of the battery 10, and the image signal picked up by the image pickup device 3 is added to the electrolyte solution. Information on the thickness of the can be included. Thereby, for example, the battery 10 with a thin electrolyte solution is treated as a non-defective product assuming that the electrolyte solution does not leak from the inside, and the battery 10 with a thick electrolyte solution leaks from the inside. Can be treated as defective. Therefore, the inspection of the battery 10 can be performed simply, at high speed, and with high accuracy compared to the conventional technique that is regarded as a defective product despite being a non-defective product.

Conventionally, since only infrared light having a wavelength that is well absorbed by the electrolytic solution (wavelength having a high absorption rate) is selectively acquired, the electrolytic solution must be diluted to obtain transmitted light. Otherwise, as shown by the curve 81 in FIG. 8, the far-infrared attenuation rate in the electrolytic solution 32 is quickly saturated, and the information included in the image signal (information on the thickness of the electrolytic solution 32) becomes scarce. It is. On the other hand, in the present embodiment, since there are a plurality of absorption bands and transmission bands in the wavelength band taken in by the imaging device 3, although the electrolytic solution 32 is purely measured, the attenuation rate is appropriate. Far infrared rays are attenuated. Therefore, as shown by a curve 82 in FIG. 8, the thickness of the electrolytic solution 32 can be detected (discriminated) over a wide range by the image signal captured by the imaging device 3 without diluting the electrolytic solution 32. It is possible to discriminate between the extremely small amount of electrolyte that adheres in the electrolyte filling process and the electrolyte that leaks from the inside at the signal level, and to detect only harmful electrolyte as reliably as possible. Become.
Further, in the present embodiment, only light having a wavelength in a band of 7 [μm] or more and 12 [μm] or less that can be selected by the imaging lens of the imaging device 3 is acquired. Even if it does not make it, it becomes possible to detect only harmful electrolyte solution as reliably as possible.

In the present embodiment, the inspection target surface 10a of the battery 10 is completely included in the irradiation region of the far infrared ray 41a irradiated from the planar light source 1 to the inspection target surface 10a of the battery 10. At the same time, the light receiving amount of the reflected light 41c reflected by the dent portion (uneven portion) 10b of the inspection target surface 10a of the battery 10 is smaller than the light receiving amount of the regular reflected light 41b. The light source 1, the imaging device 3, and the battery 10 are arranged.
Therefore, not only the electrolytic solution 32 but also the dent portion 10b can be simultaneously detected with high accuracy from the image signal imaged by the imaging device 3, and the inspection of the battery 10 is further simplified, high-speed, and high accuracy. Can be done.
From the above, in this embodiment, the inspection speed of the inspection line of the battery 10 can be improved. Therefore, the productivity of the battery 10 can be improved. Further, the number of inspectors for visually inspecting the battery 10 can be greatly reduced.

  In the present embodiment, the case where light having a predetermined wavelength is selectively acquired by the imaging lens of the imaging device 3 has been described as an example. However, light having a predetermined wavelength is not necessarily selected in this way. There is no need to get into. For example, the light transmitted through the imaging lens of the imaging device 3 may be output to a bandpass filter that passes only a predetermined wavelength, and light having a predetermined wavelength may be selectively acquired by the bandpass filter. .

  In the present embodiment, at least one of the concentration peak value, the integrated concentration value, and the area value calculated by the concentration peak value deriving unit 58, the concentration integrated value deriving unit 59, and the area deriving unit 60 is a threshold value. In the above case, the case where the battery 10 is determined to be defective has been described as an example. However, it is not always necessary to determine whether or not the battery 10 is a non-defective product in this way. For example, the following may be used.

First, when the concentration integrated value calculated by the concentration integrated value deriving unit 59 is equal to or greater than the fourth threshold value, the battery 10 is determined to be defective regardless of the concentration peak value and the area value.
On the other hand, if the integrated density value calculated by the integrated density value deriving unit 59 is less than the fourth threshold value and greater than or equal to the fifth threshold value, the concentration peak value and area calculated by the concentrated peak value deriving unit 58 It is determined whether the area value calculated by the deriving unit 60 is equal to or greater than the first and third threshold values. When at least one of the concentration peak value calculated by the concentration peak value deriving unit 58 and the area value calculated by the area deriving unit 60 is equal to or greater than a threshold value, the battery 10 is determined to be a defective product. To do.

On the other hand, when both the concentration peak value calculated by the concentration peak value deriving unit 58 and the area value calculated by the area deriving unit 60 are less than the threshold value, the battery 10 is determined to be a non-defective product.
Furthermore, when the concentration integrated value calculated by the concentration integrated value deriving unit 59 is less than the fifth threshold value, the battery 10 is determined to be a good product regardless of the concentration peak value and the area value.

  In the present embodiment, the battery 10 is heated by the heating device 6 to give a pressure difference between the inside and the outside of the battery 10 to promote the leakage of the electrolyte solution inside the battery 10. The means for promoting leakage of the electrolyte solution in the battery 10 is not limited to this. For example, by placing the battery 10 in a vacuum, a pressure difference may be given between the inside and the outside of the battery 10 to promote leakage of the electrolyte solution inside the battery 10. Further, the battery 10 is pushed in from the both side surfaces of the body of the battery 10 toward the inside of the battery 10 with a force that does not cause permanent deformation of the battery 10 and damage to the sealing portion of the battery 10. Thus, the internal pressure of the battery 10 may be increased.

In the present embodiment, the case where the battery 10 is placed on the belt conveyor has been described as an example. However, the inspector may directly place the battery 10 in the inspection area without providing the belt conveyor. .
Further, after the electrolyte inside the battery 10 is deposited in white (for example, after being left for several days after the battery 10 is manufactured), the battery 10 is inspected using the battery inspection system of this embodiment. Good. In this way, the image signal of the portion of the electrolyte leaked from the inside of the battery 10 can be made clearer due to the effects of both absorption and scattering of far infrared rays, and leaked from the inside of the battery 10. The electrolytic solution can be detected with higher accuracy.

  Further, in the present embodiment, the case where there is one inspection target surface 10a of the battery 10 has been described as an example. However, as illustrated in FIG. 9, a plurality of inspection target surfaces 10a to 10c are included in one imaging device 3. It is also possible to inspect at once. In this case, all the following conditions (C) to (E) are satisfied.

(C) Irradiation surface of the planar light source 1a so as to satisfy both the conditions (A) and (B) described above for the inspection target surface 10a, the planar light source 1a, and the imaging device 3 of the battery 10. And the arrangement of the planar light source 1a, the imaging device 3, and the battery 10 are determined.
(D) Irradiation surface of the planar light source 1b so as to satisfy both the conditions (A) and (B) described above for the inspection target surface 10b, the planar light source 1b, and the imaging device 3 of the battery 10. And the arrangement of the planar light source 1b, the imaging device 3, and the battery 10 are determined.

(E) The size of the irradiation surface of the planar light source 1c for the inspection target surface 10c, the planar light source 1c, and the imaging device 3 of the battery 10 so as to satisfy both (A) and (B) described above. In addition, the arrangement of the planar light source 1c, the imaging device 3, and the battery 10 is determined.
If it does in this way, the reflected light reflected by three mutually different test object surfaces 10a-10c can be imaged with one imaging device 3 (it can receive with one light-receiving surface). Therefore, in the same manner as described above, the inspection of the battery 10 can be performed easily and with high accuracy, and the number of the imaging devices 3 can be reduced. Furthermore, since a wider range of inspections are performed collectively, the inspection of the battery 10 can be performed at a higher speed.

In the present embodiment, the PC 4 controls the temperature control device 2, the imaging device 3, and the heating device 6. However, at least one of the temperature control device 2, the imaging device 3, and the heating device 6 is It may be independent from the PC 4 and may be manually operated by an inspector (user).
In the present embodiment, the planar light source 1 emits far infrared rays having a wavelength of 3 [μm] or more and 70 [μm] or less when the surface temperature is 50 [° C.] If far infrared rays (here, light having a wavelength of 3 [μm] or more and 1000 [μm] or less) are irradiated, the far infrared rays irradiated from the planar light source 1 are those described in this embodiment. It is not limited to.

  In this embodiment, light having a wavelength of 7 [μm] or more and 12 [μm] or less is selectively acquired. However, it is not always necessary to selectively acquire light having such a wavelength. For example, in order to distinguish a very small amount of the electrolyte that is not leaked from the electrolyte and an amount of the electrolyte that is apparently caused by the leak, and to allow the electrolyte attached to the surface of the battery 10 to permeate to some extent, The round-trip transmittance T when the thickness d is 0.5 [μm] is 0.8 (80 [%]) or more, preferably 0.9 (90 [%]) or more, more preferably 0.93 ( 93 [%]) or more, it is possible to select and acquire light having a wavelength in a predetermined range including a wavelength of not less than 93 [%]). Further, light having a wavelength in a predetermined range may be selected and acquired from wavelengths in which the round-trip transmittance T when the thickness d of the electrolytic solution is 0.5 [μm] falls within such a range. Good.

The embodiment of the present invention described above can be realized by a computer executing a program. Further, a means for supplying the program to the computer, for example, a computer-readable recording medium such as a CD-ROM recording such a program, or a transmission medium for transmitting such a program may be applied as an embodiment of the present invention. it can. A program product such as a computer-readable recording medium in which the program is recorded can also be applied as an embodiment of the present invention. The above programs, computer-readable recording media, transmission media, and program products are included in the scope of the present invention.
In addition, the above-described embodiments are merely examples of implementation in carrying out the present invention, and the technical scope of the present invention should not be construed as being limited thereto. That is, the present invention can be implemented in various forms without departing from the technical idea or the main features thereof.

It is the figure which showed embodiment of this invention and showed an example of schematic structure of a battery test | inspection system. It is a figure which shows embodiment of this invention and shows an example of the absorption curve which shows the relationship between the absorption factor and wavelength of the far infrared rays in the electrolyte solution inside a battery. It is the figure which showed embodiment of this invention and showed an example of a mode that the far infrared rays irradiated to the test object surface of the battery from the planar light source reflected on the test object surface. It is a figure which shows embodiment of this invention and demonstrates an example of the relationship of arrangement | positioning of a planar light source, an imaging device, and a battery. 1 is a block diagram illustrating an example of a functional configuration of a computer main body provided in a battery inspection system according to an embodiment of the present invention. It is a flowchart which shows embodiment of this invention and demonstrates an example of the processing operation of a battery test | inspection system. 1 illustrates an embodiment of the present invention, and details of a method for determining the size of a planar light source, the planar light source, an imaging device, and the arrangement of the battery when detecting a dent portion formed on the inspection target surface of the battery It is a figure explaining an example. It is the figure which showed embodiment of this invention and showed an example of the relationship between the thickness of electrolyte solution, and the attenuation factor of the far-infrared ray in the electrolyte solution. 1 is a diagram illustrating an example of a configuration in a battery inspection system in a case where a plurality of surface light sources and one imaging device are used to collectively inspect a plurality of inspection target surfaces of a battery according to an embodiment of the present invention. .

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Planar light source 2 Temperature control apparatus 3 Imaging device 4 PC
5 defective product discharge mechanism 6 heating device 10 battery 10a inspection target surface 10b dent portion 32 electrolyte

Claims (17)

A planar light source that irradiates far-infrared rays onto the surface to be inspected of the battery
An acquisition means for detecting the reflected light reflected by the inspection target surface of the battery by irradiating far-infrared rays to the inspection target surface of the battery by the planar light source;
Determination means for determining whether or not the battery is abnormal based on the amount of reflected light acquired by the acquisition means;
The acquisition means emits light having a wavelength in a predetermined range including a wavelength at which the round-trip transmittance is 0.8 or more when the thickness of the electrolyte attached to the surface to be inspected of the battery is 0.5 [μm]. A battery inspection system selected from the reflected light.   The battery inspection system according to claim 1, wherein the acquisition unit acquires light having a wavelength of 7 [μm] or more and 12 [μm] or less from the reflected light.   The inspection target surface of the battery is completely included in the irradiation range of far infrared light irradiated from the planar light source toward the inspection target surface of the battery. The battery inspection system described. By receiving far-infrared rays on the inspection target surface of the battery by the planar light source, the light receiving unit receives light in the irradiation region of specularly reflected light reflected on the inspection target surface of the battery. The face is completely included,
The amount of reflected light acquired by the acquisition unit from the reflected light reflected by the uneven portion of the surface to be inspected of the battery by irradiating far-infrared rays to the surface to be inspected of the battery by the planar light source, The battery inspection system according to claim 3, wherein the amount of reflected light is smaller than the amount of reflected light acquired by the acquisition unit from the regular reflected light.   Based on the amount of reflected light acquired by the acquisition unit, the determination unit determines whether or not the electrolyte solution is leaking from the inside of the battery and whether or not there is a concavo-convex portion on the inspection target surface of the battery. The battery inspection system according to claim 4, wherein determination is performed simultaneously.   In the image signal based on the amount of reflected light acquired by the acquisition unit, the determination unit includes a maximum concentration value of a portion corresponding to the electrolytic solution and the uneven portion, an area value of the portion, and a concentration integral of the portion. The battery inspection system according to claim 5, wherein a value is obtained. Having leakage promoting means for promoting leakage of the electrolyte inside the battery;
The said planar light source irradiates a far-infrared ray with respect to the test object surface of the said battery after leakage of the said electrolyte solution is accelerated | stimulated by the said leakage promotion means. The battery inspection system according to claim 1. A plurality of the planar light sources;
Each of the plurality of planar light sources irradiates far-infrared rays on different inspection target surfaces of the battery,
The acquisition means receives the reflected light reflected on each inspection target surface by one light receiving surface by irradiating each inspection target surface of the battery with far infrared rays from the plurality of planar light sources. The battery inspection system according to any one of claims 1 to 7, wherein: An irradiation step of irradiating far-infrared rays from the planar light source to the inspection target surface of the battery,
An acquisition step of detecting reflected light reflected by the inspection target surface of the battery and obtaining a reflected light amount by irradiating far-infrared rays in the irradiation step;
A determination step of determining whether the battery has an abnormality based on the amount of reflected light acquired by the acquisition step;
In the obtaining step, light having a wavelength in a predetermined range including a wavelength at which the round-trip transmittance is 0.8 or more when the thickness of the electrolyte attached to the surface to be inspected of the battery is 0.5 [μm]. A battery inspection method comprising: selecting and acquiring the reflected light.   10. The battery inspection method according to claim 9, wherein in the obtaining step, light having a wavelength of 7 [μm] or more and 12 [μm] or less is selected and obtained from the reflected light.   10. The inspection target surface of the battery is completely included in an irradiation range of far-infrared light irradiated from the planar light source toward the inspection target surface of the battery. Or 10. The battery inspection method according to 10. By irradiating far-infrared rays with respect to the inspection target surface of the battery by the planar light source, light is emitted in the acquisition step into the irradiation region of specularly reflected light reflected by the inspection target surface of the battery. So that the light-receiving surface is completely included.
The amount of reflected light obtained in the obtaining step from the reflected light reflected by the concavo-convex portion of the inspection target surface of the battery by irradiating far-infrared rays to the inspection target surface of the battery by the planar light source, The battery inspection method according to claim 11, wherein the amount of reflected light is smaller than the amount of reflected light obtained in the obtaining step from the regular reflected light.   In the determination step, based on the amount of reflected light acquired in the acquisition step, whether or not the electrolyte solution is leaking from the inside of the battery and whether or not there is a concavo-convex portion on the inspection target surface of the battery. The battery inspection method according to claim 12, wherein the determination is performed simultaneously.   In the image signal based on the amount of reflected light acquired in the acquisition step, the determination step includes a maximum value of a concentration corresponding to the electrolytic solution and the uneven portion, an area value of the portion, and a concentration integration of the portion. The battery inspection method according to claim 13, wherein a value is obtained. Having a leakage promoting step of promoting leakage of the electrolyte inside the battery;
10. The irradiation step irradiates far-infrared rays from the planar light source onto the inspection target surface of the battery after the leakage of the electrolytic solution is promoted by the leakage promotion step. The battery inspection method according to any one of -14. The irradiation step irradiates far-infrared rays from a plurality of planar light sources to different inspection target surfaces of the battery,
In the obtaining step, far-infrared rays are irradiated to each inspection target surface of the battery by the plurality of planar light sources, so that reflected light reflected on each inspection target surface is received by one light receiving surface. The battery inspection method according to claim 9, wherein the battery inspection method is performed.   The irradiation step irradiates far-infrared rays from the planar light source to the inspection target surface of the battery after the electrolyte solution attached to the inspection target surface of the battery is discolored. The battery inspection method according to any one of 9 to 16.

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