JP2009059869A - Capacitor inspection method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitor inspection method which ensures at a high level a capacitor used for various kinds of electronic device through non-destructive test. <P>SOLUTION: The capacitor is comprised of: an element 1 whose positive and negative electrodes are led out from both ends; a metal case 5 housing the element 1; and a terminal board 6 provided at the opening of the metal case 5. Laser light is irradiated to the capacitor from the external surface of the terminal board 6 and the metal case 5, and a surface not irradiated by laser of the terminal board 6 and the metal case 5 of a capacitor in which one electrode of the element 1 is bonded to the internal surface of the terminal board 6 and the other electrode to the internal bottom of the metal case 5, respectively, is set as a reference surface. The terminal board 6 and the metal case 5 which are shifted by a specified distance to the side of the element 1 from the reference surface, and their sectional photo data are acquired by using an X-ray CT apparatus. According to the bonding area of the terminal board 6 and the metal case 5 and a collector is calculated, so as to determine whether the welding condition between the terminal board 6 and the metal case 5 and the element 1 is normal. Thus, the welding condition of the capacitor is accurately determined through the non-destructive test. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a capacitor used in various electronic devices, and in particular, by welding the electrodes formed on both end faces of the element to the metal case and the terminal plate, one electrode is removed from the metal case and the other electrode is removed. The present invention relates to a method for inspecting a capacitor, which is optimal when inspecting the welding state of an end face current collecting type capacitor that is taken out from a terminal plate.

  7 is a cross-sectional view showing the configuration of this type of conventional capacitor, and FIGS. 8A and 8B are a developed perspective view and a perspective view showing the configuration of the elements used in the capacitor. In FIG. 8, 11 is an element, and this element 11 is constructed by winding a pair of electrodes 12 with a separator 14 interposed therebetween.

  The pair of electrodes 12 is formed by forming polarizable electrode layers 13a and 13b made of activated carbon, a binder and a conductive mixture on the surface excluding the exposed portions 12a and 12b provided at one end of the current collector. The exposed portions 12a and 12b are arranged so as to protrude in opposite directions, and are wound so that a pair of electrodes are taken out from both end faces of the element 11, respectively.

  15 is a metal plate connected to one end face of the element 11, 16 is a bottomed cylindrical metal case that houses the element 11, 16a is a protrusion provided on the inner bottom surface of the metal case 16, and 17 is the metal A sealing plate sealing the opening of the case 16, 18 is a rod-shaped core member provided with an external connection terminal 18 a at one end, 19 is an external connection terminal joined to the outer surface of the metal case 16, 20 Is an insulating member for insulating the core 18 from the metal case 16, 21 is a closed body made of a rubber-like elastic insulating member for constituting a pressure regulating valve in combination with the cap 22, and 23 is an O-ring. .

  The conventional capacitor configured as described above can reduce the internal resistance of the capacitor, and can reduce the size and the number of components.

As prior art document information related to the invention of this application, for example, Patent Document 1 is known.
JP 2006-210960 A

  However, since the conventional capacitor has a configuration in which one electrode of the element 11 is joined to the inner bottom surface of the metal case 16 by laser welding, it is difficult to confirm the state of this laser welding. However, there is a problem that it is difficult to ensure high accuracy with such an inspection method.

  An object of the present invention is to solve such a conventional problem and to provide a capacitor inspection method capable of guaranteeing a welding state with high accuracy by nondestructive inspection.

  In order to solve the above problems, the present invention provides an element configured to take out positive and negative electrodes from both end faces, a metal case containing the element together with a driving electrolyte, and an opening of the metal case. It consists of a terminal plate installed, and this terminal plate and the outer surface of the metal case are each irradiated with laser light, and one electrode of the element is joined to the inner surface of the terminal plate, and the other electrode is joined to the inner bottom surface of the metal case A method for inspecting a capacitor in which the terminal plate and the surface of the metal case that are not irradiated with laser light are used as a reference surface, and the terminal plate and the X of the metal case that are translated from the reference surface to the element side by a predetermined distance. One or more cross-sectional photographs taken with a line CT apparatus are taken, and the junction area between the terminal plate and the metal case and the current collector is calculated from the density of the cross-sectional photograph. By comparing the set beforehand the area, but the method to determine the quality of the welding state between the terminal plate and metal case and the device.

  As described above, the method for inspecting a capacitor according to the present invention has an effect that the quality of a welded state can be accurately determined by a nondestructive inspection by a method for inspecting a welded state from a cross-sectional photograph by an X-ray CT apparatus. Is.

(Embodiment 1)
Hereinafter, the invention described in the first to third aspects of the present invention will be described using the first embodiment.

  1A to 1C are a plan view, a front sectional view, and a bottom view showing the configuration of the capacitor according to the first embodiment of the present invention, and FIG. 2 is an enlarged sectional view of a main part of the laser welding portion of the capacitor. 1 and 2, 1 is an element, 1a is a hollow portion formed in the element 1, and this element 1 is a polarizable electrode layer except for one end on a current collector 2a made of aluminum foil. The anode electrode 2 formed with 2b and the cathode electrode 3 with the polarizable electrode layer 3b formed on the current collector 3a made of aluminum foil except for one end are overlapped in opposite directions, and the separator 4 is interposed therebetween. 1 is configured such that each of the polarizable electrode layer-unformed portions of the anode electrode 2 and the cathode electrode 3 is exposed at the opposing end surfaces, and both end surfaces of the element 1 (in the vertical direction in FIG. 1) ) To the anode electrode part 2c Is obtained by the polar electrode portions 3c to extract respectively.

  5 is a bottomed cylindrical metal case made of aluminum containing the element 1 together with a driving electrolyte solution (not shown), and 5a is a joint provided at a plurality of locations so as to project in a strip shape on the inner bottom surface of the metal case 5. The cathode electrode portion 3c provided on one end face of the element 1 inserted into the metal case 5 by this joining portion 5a is crushed, and laser welding is performed by irradiating the joining portion 5a with laser light from the outside. By doing (welding mark 5b), the metal case 5 and the cathode electrode portion 3c of the element 1 are mechanically and electrically joined, and the cathode of the element 1 is taken out from the metal case 5.

  6 is an aluminum terminal plate, 6a is a joint provided at a plurality of locations so as to protrude in the form of a strip on the inner surface of the terminal plate 6, and 6b is a terminal portion for external connection. The anode electrode portion 2c provided on the other end face of 1 is crushed, and this joint portion 6a is mechanically and electrically joined by irradiating a laser beam from the outside and laser welding (welding trace 6c), The anode of the element 1 is taken out from the terminal plate 6.

  7 is an annular insulating member that is disposed between the outer peripheral surface of the terminal plate 6 and the inner peripheral surface of the metal case 5 and insulates the two, and the outer peripheral surface of the metal case 5 is subjected to lateral drawing. It is positioned by. Reference numeral 8 denotes a sealing rubber which is disposed on the periphery of the upper surface of the terminal plate 6 and is compressed and sealed by curling the opening end of the metal case 5. Reference numeral 9 denotes a pressure regulating valve provided so as to close the electrolyte injection hole provided in the terminal plate 6.

  Also, laser welding (welding mark 6c) between the anode electrode portion 2c of the element 1 and the joint portion 6a of the terminal plate 6 (laser welding of the cathode electrode portion 3c of the element 1 and the joint portion 5a of the metal case 5 ( The same applies to the joining by the welding mark 5b). As shown in detail in FIG. 2, the anode 2c protrudes from the current collector 2a, which is a portion where the polarizable electrode layer of the anode 2 is not formed. The current collector 2a is crushed by the joint 6a provided on the terminal plate 6, and laser light is irradiated from the direction of the arrow in the figure to the portion where the plurality of current collectors 2a overlap, and laser welding is performed at the weld mark 6c portion. A method for inspecting the welded state of the parts joined by laser welding in this way will be described in detail below.

(Example 1)
3A to 3C are a cross-sectional view showing a welding state of a laser welded portion between the anode electrode portion 2c of the element 1 and the joint portion 6a of the terminal plate 6, and a slice plane A in FIG. 2 is a cross-sectional photograph of the X-ray CT apparatus and a cross-sectional photograph of the slice plane B by the X-ray CT apparatus. In this inspection, the surface of the terminal plate 6 not irradiated with the laser light is used as a reference plane. One or more cross-sectional photographs are taken by the X-ray CT apparatus of the terminal board 6 that has been translated by a predetermined distance to the side, and the cross-sectional photographs taken by the X-ray CT apparatus are manufactured by Toshiba IT Control Systems Corporation. Of TOSCANER-32250 μhd.

  In FIG. 3 (b), the white portions at both ends are taken from the metal inside the terminal plate 6 where laser welding is not performed, and the black portion at the center except for both ends is laser welded. It is a welding mark 6c, and the part 6a of the terminal plate 6 is melted and dented by laser welding, so that a blank part is photographed.

  In FIG. 3 (c), the weld mark 6c is shown in white because the joined portion 6a of the terminal plate 6 made of aluminum and the current collector 2a made of aluminum constituting the anode electrode portion 2c are melted to form an alloy. It can be seen that good welding is performed by superimposing with the cross-sectional photograph of FIG. The junction area between the junction 6a of the terminal board 6 and the current collector 2a is calculated from the density of such a cross-sectional photograph, and the calculated junction area is compared with a preset area, whereby the terminal board 6 and the element are compared. The quality of the welded state with 1 is determined.

(Example 2)
4 (a) to 4 (c) are cross-sectional views showing the welding state of the laser welded portion of another sample subjected to laser welding in the same manner as in Example 1, and X on the slice plane A in FIG. 4 (a). FIG. 4B is a cross-sectional photograph taken by the line CT apparatus and a cross-sectional photograph taken by the X-ray CT apparatus on the slice plane B. In FIG. 4B, both ends of the welding mark 6c are shown in black in the joining portion of the terminal plate 6 by laser welding. 6a has been melted and recessed, and a blank portion was taken. However, the fact that the central portion of the weld mark 6c is white indicates that the joint 6a of the terminal plate 6 is partially raised.

  In FIG. 4 (c), both ends of the weld mark 6c are shown in white as in the case of the first embodiment, where the junction 6a of the terminal plate 6 and the current collector 2a constituting the anode electrode portion 2c are melted. It can be seen that good welding is performed, but the central portion of the weld mark 6c is shown in black because the joint 6a of the terminal plate 6 is partially The part that is empty because it is raised was taken.

  Accordingly, when the central portion of the weld mark 6c is judged to overlap with the cross-sectional photograph of FIG. 4B, the current collector 2a constituting the anode electrode portion 2c is dented for some reason, whereby the terminal plate 6 This is caused by the occurrence of a gap (1 mm or more) with the joint portion 6a of this, and thus the laser light irradiated from the outer surface of the terminal plate 6 does not reach the current collector 2a. Only the joint portion 6a melts and solidifies, and this portion is raised, indicating that the welded state is abnormal.

(Example 3)
5A to 5C are cross-sectional views showing the welded state of the laser welded portion of another sample laser-welded in the same manner as in Example 1, and X on the slice plane A in FIG. FIG. 5B is a cross-sectional photograph taken by the line CT apparatus and a cross-sectional photograph taken by the X-ray CT apparatus at the slice plane B. In FIG. 5B, the welding mark 6 c appears white as a whole is raised from the laser irradiation surface. It shows that.

  In FIG. 5 (c), there are few white portions in the weld mark 6c because the joined portions 6a of the terminal plate 6 and the current collector 2a constituting the anode electrode portion 2c are melted and alloyed. This means that there are only a small number of portions, and when judging by overlapping with the cross-sectional photograph of FIG. 5B, the current collector 2a constituting the junction 6a of the terminal plate 6 and the anode electrode portion 2c Is not sufficiently melted, and therefore, the welding strength is low, indicating that the welding state is abnormal.

Example 4
6 (a) to 6 (d) are cross-sectional views showing the welding state of the laser welded portion of another sample subjected to laser welding in the same manner as in Example 1, and X on the slice plane A in FIG. 6 (a). The cross-sectional photograph by the line CT apparatus, the cross-sectional photograph by the X-ray CT apparatus at the slice plane C, and the cross-sectional photograph by the X-ray CT apparatus at the slice plane B. In FIG. 6B, the welding mark 6c is shown in black. The part 6a of the terminal plate 6 is melted and dented by laser welding, and a blank part is photographed.

  In FIG. 6 (d), the welding mark 6c is shown in white because the current collector 2a constituting the joint portion 6a of the terminal plate 6 and the anode electrode portion 2c is melted as in the first embodiment. Although it has been alloyed and it can be seen that good welding has been performed, the fact that a part of the weld mark 6c is shown in black means that no metal is present.

  FIG. 6 (c) shows a slice of only the terminal board 6 between the slice plane A and the slice plane B, but there is also a black portion in this cross-sectional photograph. This means that there is no metal. Therefore, when the portion where this metal does not exist is judged by overlapping with the cross-sectional photographs of FIGS. 6 (b) and 6 (d), the joint 6a of the terminal board 6 is connected to the inside. It can be seen that a hole communicating with the outside is generated, indicating that the welding state is abnormal.

  In FIG. 6 (c), if there is no portion where no metal is present, there is no generation of a hole communicating the inside and the outside in the joint 6a of the terminal plate 6, and a depression is generated. It can be judged. In this case, it is possible to measure the remaining thickness of the joint portion 6a of the terminal plate 6 by changing the position of the slice surface and taking a plurality of cross-sectional photographs, and the welded state is determined from this thickness. Can be determined.

  As described above, the method for inspecting a capacitor according to the present invention has a special effect that the quality of a welding state can be accurately determined by nondestructive inspection by a method for inspecting a welding state from a cross-sectional photograph by an X-ray CT apparatus. It is what you play.

(Embodiment 2)
The second aspect of the present invention will be described below with reference to the second embodiment.

  In this embodiment, in the capacitor inspection method described in the first embodiment, before taking a cross-sectional photograph by an X-ray CT apparatus, the height of the capacitor is measured by using a displacement sensor, thereby Measurement is performed after correcting the inclination.

  Specifically, a method using a so-called displacement sensor that irradiates light to a measured part from a light source, detects the reflected light with a sensor, and measures the height of the measured part by processing this information. From the measurement data, the height of the surface of the terminal plate 6 (or metal case 5) to be measured, which is not irradiated with laser light (preferably on the outer periphery side) is measured using a displacement sensor at three or more points. The inclination of the capacitor is obtained, and the inclination of the capacitor is corrected based on the result.

  As described above, the capacitor inspection method according to the present embodiment stabilizes highly accurate inspection by correcting the inclination of the capacitor and then taking a cross-sectional photograph of the welded portion of the capacitor with an X-ray CT apparatus. It has a special effect of being able to do it.

  The method for inspecting a capacitor according to the present invention has an effect that it is possible to accurately determine the quality of a welded state by nondestructive inspection, and particularly as a capacitor for an automobile that requires high reliability and a severe use environment. Useful.

(A) The top view which showed the structure of the capacitor by Embodiment 1 of this invention, (b) The front sectional drawing, (c) The bottom view Cross-sectional view of the main part, enlarging the laser welding part of the capacitor (A) A cross-sectional view showing a welding state of a laser welded portion of the capacitor, (b) a cross-sectional photograph of the slice plane A by an X-ray CT apparatus, and (c) a cross-sectional photograph of the slice plane B by an X-ray CT apparatus. (A) A cross-sectional view showing a welding state of a laser welded portion of the capacitor, (b) a cross-sectional photograph of the slice plane A by an X-ray CT apparatus, and (c) a cross-sectional photograph of the slice plane B by an X-ray CT apparatus. (A) A cross-sectional view showing a welding state of a laser welded portion of the capacitor, (b) a cross-sectional photograph of the slice plane A by an X-ray CT apparatus, and (c) a cross-sectional photograph of the slice plane B by an X-ray CT apparatus. (A) a cross-sectional view showing a welding state of a laser welded portion of the capacitor, (b) a cross-sectional photograph of the slice plane A by an X-ray CT apparatus, (c) a cross-sectional photograph of the slice plane C by an X-ray CT apparatus, (D) A cross-sectional photograph of the slice plane B using an X-ray CT apparatus Sectional view showing the structure of a conventional capacitor (A) The expansion | deployment perspective view which showed the structure of the element used for the capacitor, (b) The perspective view

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Element 1a Hollow part 2 Anode electrode 2a, 3a Current collector 2b, 3b Polarization electrode layer 2c Anode electrode part 3 Cathode electrode 3c Cathode electrode part 4 Separator 5 Metal case 5a, 6a Joint part 5b, 6c Weld trace 6 Terminal board 6b Terminal portion 7 Insulating member 8 Sealing rubber 9 Pressure regulating valve

Claims (4)

A pair of positive and negative electrodes formed on the surface of a current collector made of metal foil, with one end removed and formed with a carbon-based electrode layer, are shifted in the opposite directions and are opposed to each other with a separator interposed therebetween. An element in which each carbon-based electrode layer unformed portion of each electrode protrudes in opposite directions, a bottomed cylindrical metal case containing the element together with a driving electrolyte, and the metal case It consists of a metal terminal plate arranged in the opening, and this terminal plate and the outer surface of the metal case are respectively irradiated with laser light to place one electrode of the element on the inner surface of the terminal plate and the other electrode as a metal. A method for inspecting a capacitor having a structure bonded to the inner bottom surface of a case, wherein the surface of the terminal plate and the metal case not irradiated with laser light is used as a reference surface, and is flattened from the reference surface to the element side by a predetermined distance. One or more cross-sectional photographs of the moved terminal plate and metal case by the X-ray CT apparatus were taken, and the junction area between the terminal plate and the metal case and the current collector was calculated from the density of the cross-sectional photograph, and this calculated A method for inspecting a capacitor in which the bonding area is compared with a preset area to determine whether the terminal plate, the metal case, and the element are welded properly. Take two or more cross-sectional photographs of the terminal plate and metal case that have been translated from the reference plane to the element side by a predetermined distance at different positions, and the two or more cross-sectional photographs are the same in the superimposed state. 2. The method for inspecting a capacitor according to claim 1, wherein if there is no metal portion at the location, it is determined that the terminal plate and the metal case have a defective portion communicating with the outside and inside of the capacitor. Three or more cross-sectional photographs of the terminal plate and metal case that have been translated from the reference plane to the element side by a predetermined distance and the X-ray CT apparatus of the metal case are taken at different positions. The capacitor inspection method according to claim 1, wherein a determination is made as to whether or not a minimum necessary wall thickness is secured for the plate and the metal case. Measure the height of the surface of the terminal plate and metal case that are not irradiated with laser light using a displacement sensor at three or more points. After correcting the capacitor inclination from this measurement data, check the quality of the welded state. The capacitor inspection method according to claim 1.