Inspection method of rivet slip processing and manufacturing method of battery

Abstract

To provide an inspection method of a rivet slip processing, capable of determining whether or not a depression expansion of an umbrella part is sufficient, and provide a manufacturing method of a battery containing the inspection method.SOLUTION: According to a present disclosed technique, a quality of a rivet slip processing for fixing a fixed material by depressing a leg part of a rivet having a head part and the leg part onto a fixed material is inspected. A rivet 1 includes: a column-like leg part; and a head part 2 provided to one end of the leg part. One that at least one part of the leg part is a cylindrical part 4 that is opened to the other end, and a concave shape part is formed to a plurality of depth positions in an inner wall surface of the cylindrical part 4 is used. An umbrella part is formed by depressing the cylindrical part 4 onto a fixed material 37, and the fixed material 37 is nipped and fixed by the head part 2 and the umbrella part. In the case where an appearance amount of the concave shape part on a front surface of the umbrella part after the rivet slip processing is within an acceptance range, it is determined that the rivet slip processing is normal, and in the case where the appearance amount is out of the acceptance range, it is determined that the rivet slip processing is in fault.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present disclosure relates to a method for inspecting a riveting process and a method for manufacturing a battery. [Background technology]

[0002] Conventionally, riveting has been performed to fix and join metal members. One example is the fixing of terminal members and current collecting members to exterior bodies in the manufacture of batteries. The results of riveting may be poor. For this reason, the quality of the results is judged after riveting. An example of such a technique is disclosed in Patent Document 1. In the technique of this document, a cross pattern is provided on a pressurizing die. During processing, the cross pattern is transferred to the head of the rivet member. By imaging this transferred pattern, it is judged whether the positional deviation of processing is within an allowable range. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-082083 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the riveting process, a rivet with a hollow cylindrical portion may be used. In particular, such rivets are often used to fasten terminal members and current collecting members in batteries. In such cases, the cylindrical portion is expanded during processing to form an umbrella portion. The umbrella portion is pressed against the object to be fixed, and the object is fixed. In such cases, the issue is not the positional accuracy of the processing, but whether the umbrella portion is sufficiently expanded by applying pressure. The technology of Patent Document 1 cannot determine whether the pressure is sufficient.

[0005] An object of the present disclosure is to provide a method for inspecting a riveting process that can determine whether or not the umbrella-shaped portion is sufficiently expanded, and also to provide a method for manufacturing a battery that includes the method for inspecting a riveting process. [Means for solving the problem]

[0006] A method for inspecting riveting in one aspect of the disclosed technology is a method for inspecting the quality of riveting in which the foot of a rivet having a head and a foot is pushed and spread over an object to fix the object, the method using a rivet that has a columnar foot and a head that is provided at one end of the foot and has a diameter larger than the foot, at least a portion of the other end of the foot is a cylindrical portion having an axial bottomed hole that opens to the other end, and has concave portions formed at multiple depth positions on an inner wall surface of the cylindrical portion, and pushing and spreading at least a portion of the cylindrical portion toward the other end over the object to form an umbrella portion, and performing a riveting process in which the object is sandwiched between the head and the umbrella portion to fix the object, the method determining that the riveting is good if the amount of appearance of the concave portion on the surface of the umbrella portion after the riveting is within a predetermined acceptance range, and determining that the riveting is bad if the amount of appearance is outside the acceptance range.

[0007] In the inspection method for riveting in the above embodiment, a rivet having a head and a foot is used to perform riveting, which fixes an object to be fixed. The quality of the riveting is determined. The rivet used has at least a part of the foot that is a cylindrical portion, and a concave portion formed at a plurality of depth positions on the inner wall surface of the cylindrical portion. In the riveting, the cylindrical portion is pushed open on the object to be fixed to form an umbrella portion. The object to be fixed is sandwiched between the head and the umbrella portion and fixed. This is the riveting. A concave portion appears on the surface of the umbrella portion after the riveting. The amount of the concave portion appearing on the surface of the umbrella portion differs depending on whether the riveting is performed well or not. If the amount of the concave portion appears too much or too little compared to the amount of the concave portion appearing when the riveting is performed well, the riveting is deemed to be defective. Therefore, an acceptable range is set in advance for the amount of the concave portion. If the actual amount of the concave portion appears within the acceptable range, the riveting is determined to be good, and if it is outside the acceptable range, the riveting is determined to be defective.

[0008] In the above-mentioned riveting inspection method, it is preferable that the concave portion is a groove portion formed on the inner wall surface in a direction intersecting with the axial direction. When the concave portion is such a groove portion, the groove portion that appears on the surface of the umbrella portion has a continuous curved shape surrounding the center of the rivet, which makes it easy to find.

[0009] In the inspection method for riveting in which the concave portion is a groove, it is preferable that the cross-sectional shape of the groove is V-shaped. This is because a clear angle difference is created between the surface of the umbrella-shaped portion after processing and the wall surface of the groove, which appears as a brightness difference on the image. This makes it easy to grasp the groove on the surface of the umbrella-shaped portion.

[0010] A method for manufacturing a battery according to another aspect of the disclosed technology is a method for manufacturing a battery having an exterior body and a power generating element built into the exterior body, with a terminal member electrically connected to the power generating element penetrating the exterior body, and includes the inspection method for riveting according to any of the above-mentioned aspects, in which a rivet is used as the terminal member, and in the riveting, the exterior body and a current collecting member connected to the power generating element are fixed to the rivet as objects to be fixed, and the rivet is electrically connected to the current collecting member to manufacture a battery. In this method, a terminal portion is created by the riveting process, in which the terminal member electrically connected to the power generating element is provided penetrating the exterior body. The quality of the riveting process is inspected by the inspection method for riveting according to any of the above-mentioned aspects.

[0011] In the battery manufacturing method of the above aspect, it is preferable that the umbrella-shaped portion is brought into contact with the current collecting member during the riveting process, and that the edge of the umbrella-shaped portion is welded to the current collecting member after the riveting process, thereby ensuring electrical continuity between the rivet and the current collecting member. Effect of the Invention

[0012] According to the disclosed technology, there is provided a riveting inspection method capable of determining whether the umbrella-shaped portion is sufficiently expanded or not, and further, there is provided a battery manufacturing method including the riveting inspection method. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is an overall perspective view showing a schematic configuration of a battery. [Diagram 2] FIG. 2 is a perspective view showing a rivet used in the embodiment. [Diagram 3] FIG. 3 is a cross-sectional view of the rivet of FIG. 2. [Figure 4] FIG. 4 is a cross-sectional view showing an assembled state before riveting. [Diagram 5] FIG. 2 is a cross-sectional view showing a state during riveting. [Figure 6] FIG. 1 is a cross-sectional view (part 1) showing the assembled state after riveting. [Figure 7] FIG. 1 is a plan view (part 1) showing the assembled state after riveting. [Figure 8] FIG. 2 is a second plan view showing the assembled state after riveting. [Figure 9] FIG. 2 is a cross-sectional view (part 2) showing the assembled state after riveting. [Figure 10] FIG. 3 is a plan view (part 3) showing the assembled state after riveting. [Figure 11] FIG. 3 is a cross-sectional view (part 3) showing the assembled state after riveting. [Figure 12] FIG. 11 is a cross-sectional view showing a situation in which an assembly state after riveting is imaged. [Figure 13] FIG. 4 is a partially enlarged cross-sectional view showing a state during welding after riveting. [Figure 14] FIG. 11 is a cross-sectional view of a rivet according to a modified example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] In this embodiment, the disclosed technology is embodied in a battery 30 shown in Fig. 1. The battery 30 has a power generating element 32 built into an exterior body 31. The power generating element 32 is a laminate of positive and negative electrode plates. The exterior body 31 is composed of a lid body 33 and a box body 34. The lid body 33 is provided with positive and negative terminal portions 35, 36. At the terminal portions 35, 36, terminal members that are electrically connected to the power generating element 32 are provided penetrating the lid body 33. The terminal portions 35, 36 are the portions of the battery 30 to which the disclosed technology is applied.

[0015] Figures 2 and 3 show a rivet 1 used as a terminal member in this embodiment. Figure 3 is a cross-sectional view taken along the AA plane in Figure 2. The rivet 1 is a metal member having a head 2 and a foot 3. The foot 3 is a columnar portion. The head 2 is a flange-shaped portion provided at one end of the foot 3 and has a larger diameter than the foot 3. The head 2 shown in Figure 2 is rectangular with rounded corners when viewed from above, and both the short side and long side dimensions are larger than the diameter of the foot 3. What is visible at the terminal portions 35 and 36 in Figure 1 is the head 2 of the rivet 1.

[0016] The foot 3 will be further described. As shown in Fig. 3, a part of the foot 3 is a hollow tubular section 4. The tubular section 4 occupies the end portion of the foot 3 opposite the head 2. In other words, an axial bottomed hole 6 is formed in an end face 5 of the foot 3 opposite the head 2. The bottomed hole 6 opens into the end face 5. The range of the foot 3 from the end face 5 to the bottom face 7 of the bottomed hole 6 constitutes the tubular section 4.

[0017] A groove portion 9 is formed on the inner wall surface 8 of the cylindrical portion 4. The groove portion 9 is a concave portion formed on the inner wall surface 8 that is recessed further than the portions other than the groove portion 9. The groove portions 9 are formed at a plurality of depth positions on the inner wall surface 8. There is a gap between the groove portions 9. The groove portion 9 in the example of FIG. 3 is formed on the inner wall surface 8, extending in a direction intersecting with the axial direction of the foot portion 3. The groove portion 9 in the example of FIG. 3 is ring-shaped. The cross-sectional shape of the groove portion 9 is V-shaped. FIG. 3 shows an example in which three ring-shaped groove portions 9 are formed.

[0018] We will now describe the riveting process using the above-mentioned rivet 1. The riveting process using the rivet 1 involves spreading at least a portion of the tubular portion 4 of the rivet 1 near the end face 5 over the object to be fixed to form an umbrella-shaped portion, and then clamping and fixing the object to be fixed between the head portion 2 and the umbrella-shaped portion. Here, we will describe an example in which terminal portions 35, 36 of a battery 30 are formed by the above-mentioned riveting process.

[0019] FIG. 4 shows the state before processing. FIG. 4 shows the state in which the parts constituting the terminal parts 35, 36 of the battery 30 are assembled to the rivet 1. FIG. 4 shows an example in which four ring-shaped groove parts 9 are formed. In addition to the rivet 1, FIG. 4 also shows the above-mentioned lid body 33. FIG. 4 also shows the current collecting member 37, insulating resin 38, and insulating resin 39. The current collecting member 37 is a conductive member that connects the terminal part 35 or the terminal part 36 to one electrode plate of the power generating element 32 in the battery 30. The insulating resin 38 is a member that insulates the rivet 1 from the lid body 33. The insulating resin 39 is a member that insulates the lid body 33 from the current collecting member 37. The lid body 33, the current collecting member 37, the insulating resin 38, and the insulating resin 39 all have through holes formed therein for passing the foot part 3 of the rivet 1 through.

[0020] In Fig. 4, the rivet 1 is depicted in a position opposite to that in Fig. 2, with the head 2 facing down and the foot 3 facing up. In Fig. 4, insulating resin 38, cover 33, insulating resin 39, and current collecting member 37 are layered in this order from below on top of the head 2 of the rivet 1 in this position. A portion of the foot 3 of the rivet 1 protrudes above the current collecting member 37. The portion of the foot 3 that protrudes above the current collecting member 37 is the tubular portion 4 described above.

[0021] The assembled state is then subjected to a riveting process. In the riveting process, the cylindrical portion 4 is pushed open by a tool 40 as shown in FIG. 5. The pushed open cylindrical portion 4 is then pressed against the current collecting member 37. For this purpose, the tool 40 is pressed against the cylindrical portion 4 with a downward force G. This is not limited to a press type, but may be a rotary type, or may be a combination of a press type and a rotary type. This process pushes the cylindrical portion 4 open over the current collecting member 37 to form an umbrella-shaped portion 10. This state is shown in FIG. 6. The umbrella-shaped portion 10 is a portion that is formed by deformation of the cylindrical portion 4 before processing.

[0022] In the state shown in Fig. 6, the cover 33 and the current collecting member 37 are sandwiched and fixed between the head 2 and the umbrella-shaped portion 10. The cover 33 and the current collecting member 37 are objects to be fixed. The umbrella-shaped portion 10 and the current collecting member 37 are in contact with each other. Therefore, the rivet 1 and the current collecting member 37 are electrically conductive. In the example shown in Fig. 6, in addition to these, the insulating resin 38 and the insulating resin 39 are also sandwiched and fixed between the head 2 and the umbrella-shaped portion 10, and are therefore objects to be fixed.

[0023] A groove 9 appears on the upward surface 11 of the umbrella-shaped portion 10 in Fig. 6. When the state shown in Fig. 6 is viewed from above, the groove 9 has a continuous curved shape. More specifically, it appears to be a ring surrounding the bottom surface 7 as shown in Fig. 7. There is a gap between the grooves 9 in Fig. 7, which is the surface 11. Fig. 7 shows a part of the current collecting member 37, the surface 11 of the umbrella-shaped portion 10, and the bottom surface 7. In Fig. 7, the edge 12 of the umbrella-shaped portion 10 is circular.

[0024] The groove 9 in Figure 7 is a ring whose diameter is smaller than the edge 12 (whole diameter is R) and larger than the bottom surface 7. In Figure 7, the groove 9 is shown as a dotted circle. Figure 7 shows an example in which three annular grooves 9 appear within the umbrella portion 10. These three grooves 9 are the three excluding the deepest one of the four grooves 9 of the rivet 1 in Figure 4 before processing. The amount of groove 9 that appears on the surface 11 varies depending on the quality of the riveting process.

[0025] If the tubular portion 4 is not sufficiently expanded during the riveting process, only a small number of grooves 9 will appear. An example of this is shown in Figure 8. In the example of Figure 8, the overall diameter R of the edge 12 is smaller than in the case of Figure 7, and only two grooves 9 appear on the inside of the edge 12. These two grooves 9 are the two shallower of the four grooves 9 on the rivet 1 before processing.

[0026] A cross-sectional view after processing in the case of FIG. 8 is shown in FIG. 9. FIG. 9 is a cross-sectional view of a scene corresponding to FIG. 6. In the example of FIG. 9, the cylindrical portion 4 is not sufficiently expanded, and the cylindrical portion 4 and the current collecting member 37 are not in close contact with each other. The cylindrical portion 4 is not deformed enough to be called an umbrella-shaped portion 10. This means that reliable electrical continuity cannot be obtained between the rivet 1 and the current collecting member 37. For this reason, the riveting processing shown in FIGS. 8 and 9 is defective.

[0027] Conversely, if the tubular portion 4 is expanded excessively, a large number of grooves 9 will appear. An example of this is shown in Figure 10. In the example of Figure 10, the overall diameter R of edge 12 is larger than in the case of Figure 7, and as many as four grooves 9 appear on the inside of edge 12. In other words, all four grooves 9 of the rivet 1 before shaping are visible.

[0028] A cross-sectional view after processing in the case of FIG. 10 is shown in FIG. 11. In the example of FIG. 11, the umbrella-shaped portion 10 spreads excessively in the horizontal direction compared to the case of FIG. 6. This is reflected in the size of the edge 12 in the plan view of FIG. 10. This may cause the umbrella-shaped portion 10 to protrude from the current collecting member 37. This may cause the insulating resin 39 to be damaged by contact with the umbrella-shaped portion 10. In addition, the umbrella-shaped portion 10 may get in the way when attaching the cover 33 to the box 34. This is why the riveting processing shown in FIGS. 10 and 11 is also defective.

[0029] In the examples shown in Figures 6 and 7, there are no problems of insufficient or excessive machining as described above, and the riveting process is good. Comparing the three plan views of Figures 7, 8, and 10, it can be seen that the quality of the riveting process can be judged by the number of grooves 9 that appear. In this example, if there are three grooves 9, it is judged to be good, but if there are more or fewer grooves 9 than that, it is judged to be defective. In other words, in this example, the acceptable range for the number of grooves 9 that appear is "more than three and less than three."

[0030] The amount of the groove 9 can be determined on an image. To do so, the state of the umbrella-shaped portion 10 after the riveting process is captured from above with a camera 41 as shown in Fig. 12. This makes it possible to obtain plan view images such as those shown in Figs. 7, 8, and 10.

[0031] In the plan view captured by camera 41, there is a difference in brightness between the surface 11 of umbrella portion 10 and the grooves 9, so the grooves 9 can be easily recognized. This is because the surface 11 is a surface that is smoothed to a certain extent by pressure applied during processing, whereas the grooves 9 are not smoothed during processing. For this reason, the surface 11 has a higher light reflectance than the grooves 9, and this appears as a difference in brightness on the image.

[0032] In particular, in this embodiment, the cross-sectional shape of groove portion 9 is V-shaped as described above, which makes it easier to create a difference in brightness between surface 11 and groove portion 9. This is because, when viewed from above, surface 11 is a nearly horizontal surface, whereas groove portion 9 is a clearly inclined surface. For this reason, even if the wall surface of groove portion 9 is originally a surface with a certain degree of smoothness, there will be a difference in brightness on the image between surface 11 and groove portion 9.

[0033] In the image captured by the camera 41, the edge 12 of the umbrella-shaped portion 10 is not necessarily easily recognizable. The edge 12 is the boundary between the surface 11 of the umbrella-shaped portion 10 and the current collecting member 37. As described above, the surface 11 is a surface that has been smoothed to a certain extent, and the surface of the current collecting member 37 is also generally a glossy surface. For this reason, it may be difficult to recognize the edge 12 on the image. Therefore, it is not realistic to judge the quality of the riveting process based on the size of the overall diameter R of the edge 12. In contrast, in this embodiment, the judgment is made based on the appearance amount of the groove portion 9 rather than the size of the edge 12, so that the judgment can be easily made on the captured image.

[0034] The rivet that is judged to be good is welded as shown in FIG. 13. That is, the laser beam L is irradiated near the edge 12 of the umbrella portion 10 to join the umbrella portion 10 and the current collecting member 37. At this time, a molten portion 13 spanning the umbrella portion 10 and the current collecting member 37 is temporarily formed. At this time, the groove 9 is formed, which has the advantage of high thermal efficiency of welding. This is because the presence of the groove 9 increases the thermal conduction resistance from the place irradiated with the laser beam L, i.e., the vicinity of the edge 12 of the umbrella portion 10, to the remaining portion of the rivet 1. Therefore, less heat escapes from the vicinity of the edge 12 and less irradiation energy of the laser beam L is required compared to the case where the groove 9 is not formed.

[0035] As mentioned above, the edge 12 of the umbrella-shaped portion 10 is not necessarily easily recognizable on the image, but this does not pose a major obstacle during welding. This is because welding is performed only on parts that are judged to have been riveted well. This is because the overall diameter R of the edge 12 should be approximately the desired size. The welding method itself is not limited to irradiation with laser light L, and other methods may be used. Welding ensures electrical continuity between the rivet 1 and the current collecting member 37.

[0036] The terminals 35, 36 of the lid 33 are formed by the above method. Thereafter, the power generating element 32 is connected to the current collecting member 37, the power generating element 32 is housed in the box 34, and the opening of the box 34 is closed with the lid 33. In this manner, the battery 30 is manufactured. In FIG. 1, the head 2 of the rivet 1 is exposed at the terminals 35, 36. The umbrella-shaped portion 10 formed by the riveting process is disposed facing inward in the battery 30 and cannot be seen from the outside.

[0037] Modifications of the rivet 1 and its post-processing judgment will be described. The number of grooves 9 may be greater. Various examples are possible for determining the acceptable range of appearance during judgment. Even for the same rivet 1, the acceptable range may be determined differently if the thickness of the object to be fastened is different. The acceptable range may be determined in advance according to the number and formation positions of the grooves 9 in the rivet 1 and the thickness of the object to be fastened. The acceptable range may have a certain width. Depending on the thickness of the object to be fastened, only a portion of the tubular portion 4 near the end face 5 may be pushed open to form the umbrella-shaped portion 10.

[0038] The groove 9 is not limited to being ring-shaped. It may be a partially interrupted "C" shape. It may also be a spiral shape as shown in FIG. 14. In the case of a spiral groove 9, the groove 9 that appears in the umbrella portion 10 after machining will also be spiral-shaped. In this case, the acceptable range of the amount of appearance is determined by the amount of turns, not the number of turns. It does not have to be limited to an integer.

[0039] As described above in detail, according to this embodiment, grooves 9 are provided at a plurality of depth positions on the inner wall surface 8 of the tubular portion 4 of the rivet 1. As a result, when the tubular portion 4 is expanded to form the umbrella-shaped portion 10 by the riveting process, the grooves 9 appear on the surface 11 of the umbrella-shaped portion 10. Thus, a riveting inspection method has been realized that can easily determine whether the riveting process is good or bad based on the amount of grooves 9 that appear on the umbrella-shaped portion 10. In addition, a battery manufacturing method including this inspection method has been realized.

[0040] The present embodiment and examples are merely illustrative and do not limit the disclosed technology in any way. Naturally, the disclosed technology can be improved and modified in various ways without departing from the spirit of the technology. For example, the shape of the head 2 of the rivet 1 is arbitrary. The groove portion 9 may be replaced by a dot-shaped recessed portion. The type of the battery 30 is not important. [Explanation of symbols]

[0041] 1 rivet 12 edge 2 heads 30 batteries 3 Foot 31 Exterior body 4 Cylindrical part 32 Power generating element 5 End face 33 Lid body 6 Bottomed hole 34 Box body 8 Inner wall surface 35 Terminal section 9 Groove 36 Terminal 10 Umbrella-shaped portion 37 Current collecting member 11 Surface

Claims

1. A riveting inspection method for inspecting the quality of a riveting process in which a rivet having a head and a foot is pushed and spread over an object to be fastened, the method comprising the steps of: As the rivet, The columnar foot portion; The head is provided at one end of the foot and has a larger diameter than the foot, At least a portion of the other end of the foot is a tubular portion having an axial bottomed hole that opens to the other end, The cylindrical portion has an inner wall surface on which recesses are formed at a plurality of depth positions, a riveting process is performed to sandwich and fix the object to the head and the umbrella-shaped portion by spreading at least a portion of the cylindrical portion toward the other end onto the object to be fixed, A riveting process inspection method in which the riveting process is judged to be good if the amount of appearance of the concave portion on the surface of the umbrella-shaped portion after the riveting process is within a predetermined acceptance range, and the riveting process is judged to be defective if the amount of appearance is outside the acceptance range.

2. 2. A method for inspecting a riveting process according to claim 1, comprising: A method for inspecting riveting processing, wherein the concave portion is a groove portion formed on the inner wall surface extending in a direction intersecting the axial direction.

3. 3. A method for inspecting a riveting process according to claim 2, comprising the steps of: A method for inspecting a riveting process in which the cross-sectional shape of the groove is V-shaped.

4. A method for manufacturing a battery, the method comprising the steps of: manufacturing a battery having an exterior body and a power generating element built into the exterior body, the battery having a terminal member penetrating the exterior body and electrically connected to the power generating element, the method comprising the steps of: The method includes a method for inspecting a riveting process according to any one of claims 1 to 3, The rivet is used as the terminal member, In the riveting process, The exterior body and a current collecting member connected to the power generating element are fixed to the rivet as the fixed object, The method of manufacturing a battery comprises electrically connecting the rivet to the current collecting member.

5. A method for producing the battery according to claim 4, comprising the steps of: In the riveting process, the umbrella-shaped portion is brought into contact with the current collecting member, the edge of the umbrella-shaped portion is welded to the current collecting member after the riveting process.

Images