JP2013195299A - Power storage element and non-destructive inspection method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power storage element capable of easily determining, when non-destructive inspection is performed, whether or not an object photographed inside a container of the power storage element such as a battery is a foreign material.SOLUTION: A power storage element includes an electrode body that has a positive electrode plate and a negative electrode plate, a container that accommodates the electrode body, and a reference material 127 that can be detected by non-destructive inspection.

Description

  The present invention relates to a power storage element and a nondestructive inspection method for the power storage element.

  Conventionally, there is a nondestructive inspection device that nondestructively detects an abnormality of a sample inside a fuel cell (see Patent Document 1). In the technique of Patent Document 1, the sample frequency is identified by comparing the natural frequency analyzed by the analysis unit and the resonance frequency measured by the measurement unit, thereby identifying the sample property. Anomalies that occur in the interior, for example, defects such as cracks and delamination, internal stress, and the like are detected nondestructively.

  By the way, conventionally, when manufacturing a battery such as welding, foreign substances such as metal particles may be mixed inside the battery container. In this case, depending on the size and position of the foreign matter, there is a risk of abnormal operation such as poor insulation inside the battery. For this reason, by performing nondestructive inspection such as CT scan on the manufactured battery, it is determined whether or not there is a foreign substance that adversely affects the battery.

JP 2010-249629 A

  However, when performing non-destructive inspection inside a battery by a non-destructive inspection device such as a CT scan, for example, a comparison target for identifying a foreign object is, for example, a current collector or rivet inside the battery. Since it differs depending on the size, there is a problem that it is difficult to accurately determine the size and position of the imaged object. In addition, since data captured as a result of the nondestructive inspection includes noise, there is a problem that it is difficult to determine whether the captured object is a foreign object or noise. For this reason, in order to accurately determine whether or not the object imaged inside the battery is a foreign object, the inspector needs experience and places a burden on the inspector.

  Therefore, the present invention has been made in view of such a situation, and when non-destructive inspection is performed, whether or not an object imaged inside a container of a storage element such as a battery is a foreign object. An object is to provide a power storage element that can be easily determined. It is another object of the present invention to provide a method for performing a non-destructive inspection to determine whether or not the storage element is abnormal.

  In order to achieve the above object, the power storage device includes an electrode body having a positive electrode and a negative electrode, and a container that houses the electrode body, and includes a reference unit that can be detected by a nondestructive inspection.

  According to this, since the reference portion that can be detected by the non-destructive inspection is included, even if a foreign substance that adversely affects the performance of the storage element is mixed at the time of manufacture, the reference portion is recognized by the non-destructive inspection. By using the result, it is possible to reduce the influence of noise when determining foreign matter. For this reason, the inspector can easily determine whether or not a foreign substance is mixed in the electric storage element by performing a nondestructive inspection.

  The reference unit may be disposed inside the container.

  According to this, since the container has a reference portion that can be detected by the nondestructive inspection, the result of the nondestructive inspection is obtained even when foreign substances that adversely affect the performance of the power storage element are mixed during the manufacturing process. Therefore, the influence of noise can be reduced. For this reason, the inspector can easily determine whether or not a foreign substance is mixed in the electric storage element by performing a nondestructive inspection.

  The electrode body may be formed by laminating and winding the positive electrode and the negative electrode, and a separator, and the reference portion may be disposed on the innermost periphery of the electrode body.

  The reference portion may have a size of 0.1 to 5.0 mm.

  According to this, since the size of the reference portion is set to 0.1 to 5.0 mm which is the same as the size determined to be a foreign matter, the size of the reference portion recognized in the nondestructive inspection can be used for the foreign matter determination. .

  Moreover, in order to achieve the said objective, it images the electrical storage element of any one of Claim 1 to 4, recognizes the reference part arrange | positioned inside the said electrical storage element from the imaged imaging result, Based on the comparison between the recognition result of recognizing the reference unit and the imaging result, it is determined whether or not the power storage element is abnormal.

  According to this, it is possible to easily determine an abnormality inside the battery.

  According to the electricity storage device of the present invention, it is possible to easily determine whether or not foreign matter is mixed in the electricity storage device by performing a nondestructive inspection. In addition, according to the nondestructive inspection method of the present invention, it is possible to easily determine an abnormality inside the battery.

It is a perspective view which shows typically the external appearance of the electrical storage element of Embodiment 1 of this invention. It is a perspective view which shows the structure at the time of isolate | separating the container main body of an electrical storage element. It is a perspective view which shows typically the external appearance of an electrode body. It is a figure which shows the arrangement position of a reference thing, and the structure of a core. It is a figure which shows the outline of a nondestructive inspection apparatus. It is a functional block diagram of a nondestructive inspection device. It is a flowchart which shows the process of a nondestructive inspection method.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Each of the embodiments described below shows a preferred specific example of the present invention. The shapes, materials, components, arrangement positions and connection forms of the components shown in the following embodiments are examples, and are not intended to limit the present invention. The invention is limited only by the claims. Therefore, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims indicating the highest concept of the present invention are not necessarily required to achieve the object of the present invention. It will be described as constituting a preferred form.

(Embodiment 1)
FIG. 1 is a perspective view schematically showing the external appearance of a power storage element. FIG. 2 is a perspective view showing a configuration when the container body of the electricity storage element is separated.

  The storage element 10 is a secondary battery that can charge electricity and discharge electricity, and more specifically, is a non-aqueous electrolyte battery such as a lithium ion secondary battery.

  As shown in the figure, the electricity storage element 10 includes a container 100, a positive electrode terminal 200, and a negative electrode terminal 300, and the container 100 includes a cover plate 110 that is an upper wall. In addition, an electrode body 120, a positive electrode current collector 130, and a negative electrode current collector 140 are disposed inside the container 100.

  Note that a liquid such as an electrolytic solution is sealed inside the container 100 of the power storage element 10, but the liquid is not shown. Moreover, the electrical storage element 10 is not limited to a non-aqueous electrolyte battery, and may be a secondary battery other than the non-aqueous electrolyte battery or a capacitor.

  The container 100 includes a container body 111 having a rectangular cylindrical shape made of metal and having a bottom, and a metal lid plate 110 that closes an opening of the container body 111. In addition, the container 100 can be hermetically sealed by welding the lid plate 110 and the container main body 111 after accommodating the electrode body 120 and the like therein.

  The electrode body 120 includes a positive electrode, a negative electrode, and a separator, and is a member that can store electricity. Specifically, the electrode body 120 is formed by winding the negative electrode and the positive electrode with a separator interposed therebetween so that the separator is sandwiched between the negative electrode and the positive electrode, and has an oval shape as a whole. In addition, in the same figure, although the ellipse shape was shown as a shape of the electrode body 120, circular shape or elliptical shape may be sufficient.

  The positive electrode terminal 200 is an electrode terminal electrically connected to the positive electrode of the electrode body 120, and the negative electrode terminal 300 is an electrode terminal electrically connected to the negative electrode of the electrode body 120. That is, the positive electrode terminal 200 and the negative electrode terminal 300 lead the electricity stored in the electrode body 120 to the external space of the power storage element 10, and in order to store the electricity in the electrode body 120, It is an electrode terminal made of metal for introducing. The positive electrode terminal 200 and the negative electrode terminal 300 are attached to a lid plate 110 disposed above the electrode body 120.

  The positive electrode current collector 130 is disposed between the positive electrode of the electrode body 120 and the side wall of the container 100, and is a member having conductivity and rigidity that is electrically connected to the positive electrode terminal 200 and the positive electrode of the electrode body 120. It is. The positive electrode current collector 130 is made of aluminum, like the positive electrode of the electrode body 120.

  The negative electrode current collector 140 is a member that is disposed between the negative electrode of the electrode body 120 and the side wall of the container 100 and has electrical conductivity and rigidity that are electrically connected to the negative electrode terminal 300 and the negative electrode of the electrode body 120. It is. The negative electrode current collector 140 is made of copper, like the negative electrode of the electrode body 120.

  FIG. 3 is a perspective view schematically showing the appearance of the electrode body. FIG. 4 is a diagram illustrating the arrangement position of the reference object and the configuration of the core.

  As shown in FIG. 3, the electrode body 120 has a winding core 126 so that the positive electrode plate 122 and the negative electrode plate 123 on which the active material is applied and the two separators 124 and 125 are alternately stacked. It is wound around the center (innermost circumference). That is, the electrode body 120 is wound so that the multilayer body 121 formed by laminating the positive electrode plate 122, the first separator 124, the negative electrode plate 123, and the second separator 125 in this order has an oval cross section. It is formed by being wound around the outer periphery of the core 126.

  More specifically, the positive electrode plate 122 and the negative electrode plate 123 are shifted from each other in the width direction (Y direction) of the long band via the separators 124 and 125, and are formed in an oval shape around the rotation axis along the width direction. It has been turned. The positive electrode plate 122 and the negative electrode plate 123 have no positive electrode active material layer formed on one end side of the winding shaft by using the edge portions in the respective shifting directions as non-active material layer formation portions. The aluminum foil that is the positive electrode substrate is exposed, and the copper foil that is the negative electrode substrate on which the negative electrode active material layer is not formed is exposed on the other end side of the winding shaft. Further, a positive electrode current collector 130 and a negative electrode current collector 140 extend in both directions in the winding axis direction (Y direction) of the electrode body 120 in a direction perpendicular to the winding axis direction (Y direction) (Z direction). Has been placed.

  The positive electrode plate 122 is obtained by forming a positive electrode active material layer on the surface of a long belt-shaped positive electrode current collector sheet made of aluminum. In addition, the positive electrode plate 122 used for the electrical storage element 10 according to the present invention is not particularly different from that conventionally used, and a commonly used one can be used.

For example, as the positive electrode active material, polyanion compounds such as LiMPO ₄ , LiMSiO ₄ , LiMBO ₃ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), lithium titanate, etc. , Spinel compounds such as lithium manganate, lithium transition metal oxides such as LiMO ₂ (M is one or more transition metal elements selected from Fe, Ni, Mn, Co, etc.), etc. can be used. .

  The negative electrode plate 123 is obtained by forming a negative electrode active material layer on the surface of a long strip negative electrode current collector sheet made of copper. In addition, the negative electrode plate 123 used in the electricity storage device 10 according to the present invention is not particularly different from those conventionally used, and those normally used can be used.

For example, as the negative electrode active material, a known material can be appropriately used as long as it is a negative electrode active material capable of occluding and releasing lithium ions. For example, lithium metal and lithium alloys (lithium metal-containing alloys such as lithium-aluminum, lithium-lead, lithium-tin, lithium-aluminum-tin, lithium-gallium, and wood alloys) and lithium can be occluded / released. Alloys, carbon materials (eg, graphite, non-graphitizable carbon, graphitizable carbon, low-temperature fired carbon, amorphous carbon, etc.), metal oxides, lithium metal oxides (Li ₄ Ti ₆ O ₁₂ etc.), polyphosphate compounds Etc.

  The winding core 126 is made of a long strip material having insulation properties such as polypropylene and polyethylene. Further, as shown in FIG. 3, the core 126 is welded at a welded portion 129 extending in the Y direction in a state of being folded in three. A reference object 127 as a reference portion is taped to the core 126 that is the innermost periphery of the electrode body 120 with an adhesive tape 128.

  The reference 127 is made of metal particles that can be detected by X-rays. The reference material 127 preferably has a particle size of 0.1 to 5.0 mm. The reference object 127 is not limited to a sphere such as a metal particle, but may be a metal piece. Thus, when the reference material 127 is a metal piece, the size is preferably 0.1 to 5.0 mm as described above. Two or more reference objects 127 may be arranged. In the case of arranging a plurality of reference objects 127, it is preferable to arrange reference objects having different sizes, which makes it possible to determine more reliably. The reference object 127 may be any substance that can be detected by X-rays. Note that “detectable by X-rays” means that, for example, when imaging is performed by irradiating X-rays, imaging is performed with a value larger than a predetermined luminance value.

  FIG. 5 is a diagram showing an outline of a nondestructive inspection apparatus for performing the nondestructive inspection method for the energy storage device according to the first embodiment. FIG. 6 is a functional block diagram of the nondestructive inspection apparatus.

  The nondestructive inspection apparatus 400 includes an X-ray irradiation unit 410, a moving unit 420, an imaging unit 430, a display unit 440, and a control unit 450. The nondestructive inspection apparatus 400 of the present embodiment is a CT scan apparatus.

  The X-ray irradiation unit 410 is an X-ray tube that irradiates an object (the power storage element 10 in the present embodiment) to be subjected to nondestructive inspection with X-rays.

  The moving unit 420 is a pedestal for placing an object to be subjected to nondestructive inspection, and is movable in the X direction, the Y direction, and the Z direction, and rotates about a virtual line parallel to the Z direction. It is a possible pedestal.

  The imaging unit 430 converts visible light by applying X-rays that have passed through the power storage element 10 to a phosphor, and changes the visible light to a CCD (Charge Coupled Device) image sensor or a CMOS (Complementary Metal Oxide Semiconductor) image sensor. It is an X-ray detector which detects by solid-state image sensors, such as. The imaging unit 430 captures an image a plurality of times (for example, 300 to 2000 times) while the moving unit 420 places and moves (mainly rotationally moves) the power storage element 10 in one nondestructive inspection. Thereby, X-ray transmission image data from all directions of 360 degrees with respect to the storage element 10 is obtained.

  The display unit 440 displays an arbitrary cross-sectional view after a plurality of X-ray transmission image data obtained as a result of imaging by the imaging unit 430 is subjected to image processing by the control unit 450. The display unit 440 is, for example, an LCD (Liquid Crystal Display).

  The control unit 450 controls each unit of the X-ray irradiation unit 410, the moving unit 420, the imaging unit 430, and the display unit 440. The control unit 450 includes an irradiation control unit 451, a movement control unit 452, an imaging control unit 453, a display control unit 454, a recognition unit 455, and an abnormality determination unit 456. The control unit 450 is, for example, a personal computer.

  The irradiation control unit 451 controls the X-ray irradiation unit 410. Specifically, the irradiation control unit 451 causes the X-ray irradiating unit 410 to irradiate the power storage element 10 placed on the moving unit 420 with X-rays.

  The movement control unit 452 controls the moving unit 420 to move in the X direction, the Y direction, and the Z direction so that the center of the power storage element 10 placed on the moving unit 420 is imaged at the center of the imaging unit 430. Let Thereafter, the movement control unit 452 controls the moving unit 420 to rotate and move the power storage element 10 moved to the position to be imaged at the center of the imaging unit 430 by 360 degrees about the virtual line parallel to the Z direction. .

  The image capturing control unit 453 controls the image capturing unit a plurality of times (for example, 300 to 2000 times) at a predetermined timing while the movement control unit 452 controls the moving unit 420 to rotate the power storage element 10 by 360 degrees. Let 430 image.

  The display control unit 454 generates cross-sectional image data at an arbitrary position based on a plurality of X-ray transmission image data obtained by imaging by the imaging unit 430, and displays the cross-sectional image indicated by the generated cross-sectional image data. 440 is displayed.

  The recognition unit 455 recognizes the reference object 127 provided in the power storage element 10 based on the cross-sectional image generated by the display control unit 454. Specifically, the recognizing unit 455 is a region corresponding to the position in the generated cross-sectional image based on the position of the reference object 127 determined in advance inside the power storage element 10 and is determined in advance. A region exceeding the luminance value is recognized as a region where the reference object 127 is imaged. That is, as a result of recognizing the reference object 127, the recognizing unit 455 corresponds the correspondence between the size of the set of areas that exceed the predetermined luminance value displayed in the cross-sectional image and the predetermined size of the reference object 127. A tag is generated as a recognition result. The recognition unit 455 recognizes the reference object 127 based on the cross-sectional image generated by the display control unit 454. However, the present invention is not limited to this, and a plurality of X-rays obtained as a result of imaging by the imaging unit 430 are used. The reference 127 may be recognized based on the transmission image data.

  The abnormality determination unit 456 performs abnormality determination to determine whether or not the power storage element 10 has an abnormality based on a comparison between the recognition result generated by the recognition unit 455 and the cross-sectional image generated by the display control unit 454. Do. Specifically, the abnormality determination unit 456 determines whether there is a foreign substance that adversely affects the performance of the storage element 10 in the imaging result obtained by imaging the inside of the storage element 10 based on the recognition result generated by the recognition unit 455. The above abnormality determination is performed by determining whether or not. That is, the size of a pixel region (high luminance pixel region) having a luminance value larger than a predetermined luminance value in the cross-sectional image is the recognition result of the reference object 127 generated by the recognition unit 455 (reference object 127). If it is included in the numerical value range (determination numerical value range) for determining the foreign matter generated on the basis of the size of the storage element 10, it is determined that the storage element 10 is abnormal. For example, it is determined whether or not the maximum width of the high luminance pixel region is included in the foreign substance size (for example, 0.1 to 5.0 mm). When the size of the high-luminance pixel area is included in the determination numerical value range, it indicates that the high-luminance pixel area is an area where foreign substances that adversely affect the performance of the power storage element 10 exist. Thus, abnormality determination unit 456 can determine that a foreign substance is mixed in power storage element 10. Further, when there is no set (area) of luminance values included in the numerical value range, it is determined that no foreign matter is mixed in the power storage element 10. When the abnormality determination unit 456 determines that the power storage element 10 is abnormal, the display control unit 454 displays information indicating the position, shape, and size of the foreign object imaged inside the power storage element 10. The inspector is notified by displaying on 440. The abnormality determination unit 456 performs abnormality determination based on the cross-sectional image generated by the display control unit 454. However, the abnormality determination unit 456 is not limited to this, and a plurality of X-ray transmissions as a result of imaging by the imaging unit 430 are performed. An abnormality determination may be performed based on the image data.

  FIG. 7 is a flowchart showing processing of a nondestructive inspection method performed by the nondestructive inspection apparatus.

  The imaging unit 430 irradiates the storage element 10 with X-rays by the X-ray irradiation unit 410, and the storage element 10 is rotated 360 degrees about a virtual axis parallel to the Z direction by the moving unit 420. An X-ray transmission image of the storage element 10 is taken (S11).

  Next, the display control unit 454 generates cross-sectional image data at an arbitrary position based on a plurality of X-ray transmission image data obtained as a result of imaging by the imaging unit 430, and the cross-sectional image indicated by the generated cross-sectional image data Is displayed on the display unit 440 (S12).

  Based on the cross-sectional image generated by the display control unit 454, the recognizing unit 455 recognizes the reference object 127 provided in the power storage element 10 (S13).

  The abnormality determination unit 456 determines whether there is an abnormality in the power storage element 10 based on the comparison between the recognition result generated by the recognition unit 455 and the cross-sectional image generated by the display control unit 454 (S14). .

  When the abnormality determination unit 456 determines that there is an abnormality in the power storage element 10 (S14: Yes), the display control unit 454 displays information indicating the position, shape, and size of the foreign object imaged inside the power storage element 10. By displaying on the display unit 440, the position, shape, and size of the foreign substance are notified to the inspector (S15), and the process according to the nondestructive inspection method is terminated.

  On the other hand, when the abnormality determining unit 456 determines that there is no abnormality in the power storage element 10 (S14: No), the display control unit 454 displays information indicating that there is no abnormality in the power storage element 10 on the display unit 440. By displaying, the inspector is notified that there is no abnormality in the power storage element 10 (S16), and the process according to the nondestructive inspection method is ended.

  According to power storage element 10 according to the present embodiment, since reference object 127 serving as a reference portion that can be detected by nondestructive inspection is provided inside container 100, a foreign substance that adversely affects the performance of the power storage element is produced during manufacturing. Even if it is mixed, the influence of noise can be reduced from the result of the nondestructive inspection. For this reason, the inspector can easily determine whether or not a foreign substance is mixed in the power storage element 10 by performing a nondestructive inspection.

  In addition, according to power storage device 10 according to the present exemplary embodiment, reference object 127 as a reference portion is provided on the innermost periphery of electrode body 120. The innermost periphery of the electrode body 120 is configured by an insulative winding core 126, and the reference object 127 is provided inside the winding core 126. Therefore, the reference object 127 adversely affects the performance of the power storage device 10. Can be reduced.

  In addition, according to the nondestructive inspection method according to the present embodiment, the reference as a reference unit disposed inside the storage element 10 from the imaging result captured by irradiating the storage element 10 with X-rays. The object 127 is recognized, and it is determined whether or not there is an abnormality in the power storage element 10 based on the comparison between the recognition result obtained by recognizing the reference object 127 and the imaging result. In this way, since the foreign object to be determined is determined using the result of recognizing the reference object 127, even if foreign substances that adversely affect the performance of the storage element are mixed at the time of manufacture, non-destructive The influence of noise can be reduced from the inspection result. For this reason, the inspector can easily determine whether or not a foreign substance is mixed in the power storage element 10 by performing a nondestructive inspection.

  In addition, according to power storage element 10 according to the above embodiment, reference object 127 as a reference portion is provided on the innermost periphery of electrode body 120, but reference object 127 ensures insulation within power storage element 10. If it is, the arrangement location is not limited to the innermost circumference of the electrode body 120. The reference 127 is not limited to being made of metal, and may be made of ceramics. In the case where the reference object 127 is made of ceramics, the reference object 127 may be at any position because it hardly affects any position inside the electric storage element 10. Furthermore, the reference unit is configured as an independent separate body like the reference object 127, but may be integrated with other components. For example, a convex portion formed on the inner wall of the container 100, a convex portion formed on the positive electrode current collector 130 or the negative electrode current collector 140 may be used as the reference portion, or may be a concave portion instead of the convex portion. That is, the reference object 127 is not limited as long as it can be detected in the nondestructive inspection.

  Further, according to the electricity storage device 10 according to the above-described embodiment, the core 126 provided with the reference object 127 is formed by welding a long belt-shaped material in a folded state. For example, the core may be provided with a hole for inserting a winding shaft of a winding device in a flat plate-like member.

  Further, according to the nondestructive inspection method according to the above-described embodiment, an image of the inside of the electricity storage element 10 is obtained by the CT scanning device. However, the present invention is not limited to this. A gamma ray) apparatus may be used, or an ultrasonic apparatus may be used. In the case of detecting by inspection other than non-destructive inspection by X-ray, the reference object 127 may be any substance that can be detected by non-destructive inspection, and is not limited to a substance detectable by X-ray.

  As mentioned above, although the electrical storage element and the nondestructive inspection method of this invention were demonstrated based on embodiment, this invention is not limited to this embodiment. Unless it deviates from the meaning of this invention, the form which carried out the various deformation | transformation which those skilled in the art can think to this embodiment, and the structure constructed | assembled combining the component in different embodiment is also contained in the scope of the present invention. .

  The power storage element according to one embodiment of the present invention is useful as a power storage element that can easily determine whether or not a foreign substance is mixed in the power storage element by performing a nondestructive inspection.

DESCRIPTION OF SYMBOLS 10 Power storage element 100 Container 110 Cover plate 111 Container main body 120 Electrode body 121 Multilayer body 122 Positive electrode plate 123 Negative electrode plate 124 First separator 125 Second separator 126 Core 127 Reference material 128 Adhesive tape 129 Welding part 130 Positive electrode current collector 140 Negative electrode Current collector 200 Positive electrode terminal 300 Negative electrode terminal 400 Non-destructive inspection device 410 X-ray irradiation unit 420 Moving unit 430 Imaging unit 440 Display unit 450 Control unit 451 Irradiation control unit 452 Movement control unit 453 Imaging control unit 454 Display control unit 455 Recognition unit 456 Abnormality determination unit

Claims (5)

An electrical storage element comprising an electrode body having a positive electrode and a negative electrode, and a container for housing the electrode body,
A power storage device including a reference portion that can be detected by nondestructive inspection. The electricity storage device according to claim 1, wherein the reference unit is disposed inside the container. The electrode body is formed by laminating and winding the positive electrode and the negative electrode, and a separator,
The electric storage element according to claim 1, wherein the reference unit is disposed on an innermost periphery of the electrode body. The electricity storage device according to any one of claims 1 to 3, wherein the reference portion has a size of 0.1 to 5.0 mm. Imaging the electricity storage device according to any one of claims 1 to 4,
Recognizing the reference portion arranged inside the electricity storage element from the imaged imaging result,
A nondestructive inspection method for determining whether or not the power storage element is abnormal based on a comparison between a recognition result obtained by recognizing the reference unit and the imaging result.

Images