JP2016091932A - Current interrupting device, method for manufacturing current interrupting device, and secondary battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a current cutoff device in which a fusion zone is prevented from being blown out even if an edge of a reverse plate of the current cutoff deice and a step part of a rivet are welded, and a blow hole is prevented from being residual even if the fusion zone is blown out, a manufacturing method of the current cutoff device, and a secondary battery.SOLUTION: In the current cutoff device, in a cross-sectional view in a forward movement direction DR1 of a laser beam LB1, a fusion boundary side face 50a of a first fusion mark 50 closer to the laser beam LB1 is tilted away from a surface 33a of an edge 33 as the side face moves in a direction opposite to the forward movement direction DR1 of the laser beam LB1.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a current interrupt device used for a secondary battery, a method for manufacturing the current interrupt device, and a structure of the secondary battery.

  A typical secondary battery includes a current interrupt device. The current interrupting device includes a current collecting terminal electrically connected to the battery element, an inversion plate joined to the current collecting terminal, an external terminal electrically connected to the inversion plate, and the like. The reversing plate receives the internal pressure, and the reversing plate is reversely deformed in a direction away from the current collecting terminal, whereby the conduction between the battery element and the external terminal is interrupted.

  Japanese Patent Application Laid-Open No. 2014-086176 (Patent Document 1), Japanese Patent Application Laid-Open No. 2013-188787 (Patent Document 2), and Japanese Patent Application Laid-Open No. 2013-212178 (Patent Document 3) disclose a step portion formed on a rivet. A technique is disclosed in which a reversing plate is disposed, and the entire peripheral portion of the edge of the reversing plate and the step portion of the rivet are butted against each other.

JP 2014-086176 A JP 2013-188787 A JP 2013-2111178 A

  When the entire circumference of the edge of the reversing plate and the stepped portion of the rivet are butted and welded, several points on the edge of the reversing plate and the stepped portion of the rivet are brought into contact with each other in advance to perform temporary fixing welding. . Thereafter, the edge of the reversing plate and the step portion of the rivet are welded over the entire circumference. At this time, when the edge of the reversing plate is placed on the step portion of the rivet, a slight gap is formed between the edge of the reversing plate and the step portion of the rivet.

  When welding the entire periphery of the edge of the reversing plate, the air present in the gap is pressed toward the front side in the laser welding forward direction (scanning direction) and gradually against the temporarily fixed welding point. The air is compressed. Furthermore, the compressed air is thermally expanded by the heat of welding (laser welding). As a result, a phenomenon occurs in which the melted metal bursts without being able to withstand the pressure of the thermally expanded air at the temporarily fixed weld. If the ruptured metal fragments adhere to the components constituting the current interrupting device, there is a concern that the confidentiality of the current interrupting device is reduced and the operating pressure of the current interrupting device is adversely affected. Moreover, since the location where the metal has ruptured remains as a blowhole, there is a concern that the confidentiality of the current interrupting device may be reduced.

  The present invention has been made in view of the above problems, and even when the edge portion of the reversing plate of the current interrupting device and the step portion of the rivet are welded, the melted portion is prevented from bursting and the melted portion is not bursted. An object of the present invention is to provide a current interrupting device, a method of manufacturing the current interrupting device, and a secondary battery that do not leave blow holes even if they occur.

  In the current interrupting device, the method for manufacturing the current interrupting device, and the secondary battery, welding is performed to a plurality of selected regions at the abutting portion between the stepped portion and the peripheral portion, and temporary fixing welding is performed. A plurality of first welding marks and a second welding mark in which the entire circumference is welded by irradiating the entire circumference with a laser beam for welding at the abutting portion between the stepped portion and the peripheral portion. And in the cross-sectional view along the forward direction of the laser beam, the melting boundary side surface of the first welding mark on the laser beam side is directed toward the opposite direction to the forward direction of the laser beam. Inclined in a direction away from the surface.

  As described above, the melting boundary side surface on the laser beam side of the first welding mark is inclined (angle θ °) in the direction away from the surface of the peripheral portion as it goes in the opposite direction to the laser beam advance direction. In addition, the air existing in the gap between the edge of the reversing plate and the step portion of the rivet is pressed toward the front side in the laser beam forward direction (scanning direction). It will be in the state which is easy to discharge | release outside outside along a slope. As a result, the rapid heating of the air existing in the gap between the edge of the reversing plate and the step portion of the rivet is reduced, the molten metal is prevented from bursting, and the scattering of metal pieces or the formation of blowholes is avoided. It becomes possible.

  According to the current interrupting device, the current interrupting device manufacturing method, and the secondary battery, even when the edge portion of the reversing plate of the current interrupting device and the step portion of the rivet are welded, the burst of the melted portion is suppressed. Even when the melted portion is ruptured, the blowhole does not remain.

It is a top view which shows the secondary battery in embodiment. It is sectional drawing which shows the secondary battery in embodiment. It is arrow sectional drawing along the III-III line in FIG. FIG. 4 is an exploded perspective view corresponding to FIG. 3. It is a disassembled perspective sectional view of the inversion board and rivet in an embodiment. It is a perspective view which shows the welding state to the rivet of the inversion board in embodiment. It is sectional drawing seen along the scanning direction at the time of irradiation of the laser beam in embodiment. It is the perspective view seen along the scanning direction at the time of the irradiation of the laser beam in a comparative example. It is sectional drawing seen along the scanning direction at the time of irradiation of the laser beam in a comparative example. It is a figure which shows the subject at the time of irradiation of the laser beam in a comparative example. It is the partial expanded sectional view seen along the scanning direction at the time of the irradiation of the laser beam in embodiment. It is the 1st perspective view seen along the scanning direction at the time of irradiation of the laser beam in an embodiment. It is the 2nd perspective view seen along the scanning direction at the time of irradiation of the laser beam in an embodiment. It is the 1st expanded sectional view seen along the scanning direction at the time of irradiation of the laser beam in an example. It is the 2nd expanded sectional view seen along the scanning direction at the time of irradiation of the laser beam in an example. It is sectional drawing seen along the scanning direction at the time of irradiation of the laser beam in a comparative example. It is a figure which shows the relationship between the crossing angle in Example 1-5 and Comparative Example 1-2, the number of airtight defects, and the number of blowholes.

  Hereinafter, embodiments will be described with reference to the drawings. When referring to the number, amount, etc., the scope of the present invention is not necessarily limited to the number, amount, etc., unless otherwise specified. The same parts and corresponding parts are denoted by the same reference numerals, and redundant description may not be repeated.

  With reference to FIGS. 1-4, the secondary battery 100 in this Embodiment is demonstrated. 1 is a plan view showing the secondary battery 100, FIG. 2 is a cross-sectional view showing the secondary battery 100, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 1, and FIG. FIG. 4 is an exploded perspective view corresponding to FIG. 3.

  Referring to FIGS. 1 and 2, secondary battery 100 includes an exterior body 10, an electrode body 13, a positive external terminal 20 and a current collecting terminal 21, and a negative external terminal 24 and a current collecting terminal 25. . The exterior body 10 includes a bottomed cylindrical accommodating portion 11 and a sealing plate 12. The exterior body 10 accommodates the electrode body 13 (battery element) inside. The external terminals 20 and 24 are attached to the sealing plate 12. The electrode body 13 has a positive electrode core body, a negative electrode core body, and a separator (all not shown), and the positive electrode core body and the negative electrode core body are wound through the separator. A positive electrode core exposed portion 14 and a negative electrode core exposed portion 15 are respectively provided at both ends of the electrode body 13.

  The positive electrode core exposed portion 14 is electrically connected to the external terminal 20 via a current collecting terminal 21 and a current interrupt device described later. The negative electrode core exposed portion 15 is electrically connected to the external terminal 24 via the current collecting terminal 25 and the current interrupt device. Since the current interrupting device for the positive electrode and the current interrupting device for the negative electrode have the same configuration, the details will be described below with a focus on the current interrupting device for the positive electrode.

  With reference to FIG. 3 and FIG. 4, the structure and manufacturing method of a current interrupting device will be described. For convenience of explanation, only the current collecting terminal 21, the reversing plate 30 (also referred to as a diaphragm), and the rivet 40 are illustrated in FIG. In addition to the current collecting terminal 21, gaskets 16, 17, 18, a conductive plate 19, a reversing plate 30, and a rivet 40 are provided in the vicinity of the sealing plate 12 and the external terminal 20 (see FIGS. 1 and 2). .

  A through hole 12H is formed in the sealing plate 12. The gaskets 17 and 18 are disposed inside the sealing plate 12 (inside the exterior body 10). The gasket 16 and the conductive plate 19 are disposed outside the sealing plate 12 (outside of the exterior body 10). The rivet 40 is caulked while being inserted into the through-hole 12 </ b> H, and fixes the conductive plate 19 and the gasket 16 to the sealing plate 12. In the state shown in FIG. 3, the current collecting terminal 21 is electrically connected to the external terminal 20 through the reversing plate 30, the rivet 40 and the conductive plate 19.

  The rivet 40 includes a caulking portion 41, a small diameter portion 42, a connection portion 43, a large diameter portion 44, and a step portion 45. The caulking portion 41 is formed on the opposite side of the small diameter portion 42 from the connection portion 43. The caulking portion 41 is formed by caulking the end portion side of the small diameter portion 42 after inserting the small diameter portion 42 into the through hole 12H. The step portion 45 is a portion formed outside the large-diameter portion 44, has an annular shape as a whole, and is provided with a step 45a. The space inside the connecting portion 43, the large diameter portion 44 and the stepped portion 45 allows the reversing plate 30 described later to be reversed.

  The inversion plate 30 includes a top surface portion 31 (inversion portion), an inclined portion 32, and a peripheral edge portion 33, and is made of an aluminum alloy or the like. The top surface portion 31 has a circular shape. The inclined portion 32 has an annular shape that surrounds the periphery of the top surface portion 31. The peripheral portion 33 of the reversing plate 30 is formed outside the inclined portion 32 and has an annular shape. In the manufacturing process, the reversing plate 30 is fixed to the rivet 40 by welding the peripheral portion 33 of the reversing plate 30 and the stepped portion 45 of the rivet 40 to each other.

  The current collecting terminal 21 includes flat plate portions 21L and 21R, a thick portion 22, a thin portion 23, a through hole 23H, and an annular groove 23G, and is made of an aluminum alloy or the like. The flat plate portions 21L and 21R are welded to the positive electrode core exposed portion 14. The current collecting terminal 21 is electrically connected to the electrode body 13 by the welding. The top surface portion 31 of the reversing plate 30 is joined to the thin portion 23 by laser welding. The through hole 23H and the annular groove 23G are both provided in the thin portion 23.

  Next, fixation of the reversing plate 30 to the rivet 40 will be described with reference to FIGS. 5 and 6. FIG. 5 is an exploded perspective sectional view of the reversing plate 30 and the rivet 40, and FIG. 6 is a perspective view showing a welding state of the reversing plate 30 to the rivet 40.

  The rivet 40 is provided with an annular step 45 on which the peripheral edge 33 of the reversing plate 30 is placed. The height of the step 45 a in the step 45 is approximately the same as the height of the peripheral edge 33 of the reversing plate 30. The radial width of the step 45 a in the step 45 is also substantially the same as the radial width of the peripheral edge 33 of the reversing plate 30.

  In the manufacturing process, as shown in FIG. 6, the peripheral portion 33 of the reversing plate 30 is placed on the step portion 45 of the rivet 40, so that a butt portion is provided between the step portion 45 and the peripheral portion 33 over the entire circumference. It is formed. Next, before welding the butted portion of the stepped portion 45 and the peripheral edge portion 33 with a laser beam over the entire circumference, temporary fixing welding is performed on a plurality of selected regions. In the present embodiment, the first welding marks 50 are formed at four positions at a pitch of 90 °. The number of the first welding marks 50 is not limited to four, and an optimal number is appropriately selected according to the size of the reversing plate 30.

  Thereafter, at the abutting portion between the step portion 45 of the rivet 40 and the peripheral portion 33 of the reversing plate 30, the entire circumference is scanned while being irradiated with the laser beam (LB1) for welding (advance: direction DR1 in the figure). Weld all around. Thereby, the 2nd welding trace 60 is formed in the perimeter of the butt | matching part of the level | step-difference part 45 and the peripheral part 33. FIG.

  Next, the cross-sectional shape of the first welding mark 50 in the present embodiment will be described with reference to FIG. FIG. 7 is a cross-sectional view taken along the forward (scanning) direction when the laser beam LB1 is irradiated. The fusion boundary side surface 50a on the laser beam LB side of the first welding mark 50 has a peripheral edge as it goes in the opposite direction (left direction in FIG. 7) to the forward direction DR1 (right direction in FIG. 7) of the laser beam LB1. Inclined in a direction away from the surface 33 a of the portion 33. The first welding mark 50 having such a shape can be formed by irradiating a laser beam from a direction (A1 direction in the figure) inclined with respect to the surface 33a of the peripheral edge portion 33.

  In addition, the 1st welding mark 50 has penetrated the fusion | melting part deeply beyond the bottom face of the level | step-difference part 45. FIG. This is to ensure the welding strength so that the reversal plate 30 is not deformed and the welding position is not changed during the entire circumference welding of the reversal plate 30. Therefore, the first welding mark 50 for performing the temporary welding has an important function in terms of reducing variation in the operating pressure of the reversing plate 30 and ensuring airtightness.

  Here, there is a preferable crossing angle (θ) in the crossing angle (θ) between the melting boundary lower surface 60s and the melting boundary side surface 50a of the second welding mark 60 formed by the irradiation of the laser beam LB1. Will be described later.

  On the other hand, with reference to FIGS. 8 to 10, the cross-sectional shape of the first welding mark 50z in the comparative example will be described. FIG. 8 is a perspective view seen along the forward (scanning) direction when the laser beam LB1 is irradiated in the comparative example, and FIG. 9 is along the forward (scanning) direction when the laser beam LB1 is irradiated in the comparative example. FIG. 10 is a cross-sectional view viewed from the above, and FIG. 10 is a diagram illustrating a problem at the time of irradiation with the laser beam LB1 in the comparative example.

  In the case of forming the first welding mark 50z, the normal laser beam is irradiated from the vertical direction with respect to the surface 33a of the peripheral edge portion 33. As a result, the first welding mark 50z has a shape that narrows toward the tip. As a result, the melting boundary side surface 50b on the laser beam LB side of the first welding mark 50z is inclined in a direction away from the surface 33a of the peripheral edge portion 33 toward the forward direction DR1 (right direction in FIG. 7) of the laser beam LB1. (The direction opposite to the melting boundary side surface 50a in FIG. 7). When the first welding mark 50z is formed by irradiating a laser beam from the direction perpendicular to the surface 33a of the peripheral edge 33, the crossing angle between the melting boundary lower surface 60s of the second welding mark 60 and the melting boundary side surface 50a. (Θ) is an angle exceeding 90 °.

  As a result, when welding the entire circumference of the peripheral edge portion 33 of the reversing plate 30, the air AR present in the gap between the peripheral edge portion 33 of the reversing plate 30 and the stepped portion 45 of the rivet 40 advances the laser beam LB1. By being pressed toward the front side in the direction DR1 (scanning direction) and surrounded by the step portion 45, the air is gradually compressed with respect to the first welding mark 50z. Further, the compressed air is thermally expanded by the heat of the laser beam LB1. As a result, there is a phenomenon in which the molten metal (mainly the peripheral portion 33 of the reversing plate 30) is ruptured without being able to withstand the pressure of the thermally expanded air near the first welding mark 50z (in the direction of arrow A in FIG. 9). ).

  If broken pieces of the peripheral edge portion 33 of the reversing plate 30 adhere to parts (such as the reversing plate 30) constituting the current interrupting device, there is a concern that the confidentiality of the current interrupting device may be reduced and the operating pressure of the current interrupting device may be adversely affected. Is done. Further, as shown in FIG. 10, the portion where the peripheral edge portion 33 of the reversing plate 30 is ruptured remains as the blow hole BH, and there is a concern that the confidentiality of the current interrupting device may be lowered.

  Therefore, as shown in FIG. 7, the first welding mark 50 in the present embodiment has a melting boundary side surface 50a on the laser beam LB1 side of the first welding mark 50 in the forward direction DR1 of the laser beam LB1 (in FIG. 7). Is inclined (angle θ °) in a direction away from the surface 33a of the peripheral edge 33 as it goes in the opposite direction (left direction in FIG. 7).

  Here, the advantage of inclining the melting boundary side surface 50a will be described with reference to FIG. 11 to FIG. FIG. 11 is a partially enlarged cross-sectional view taken along the forward (scanning) direction during irradiation with the laser beam LB1, and FIGS. 12 and 13 show the forward (scanning) direction during irradiation with the laser beam LB1. It is the 1st and 2nd perspective view which looked.

  As shown in FIG. 11, the melting boundary side surface 50a on the laser beam LB1 side of the first welding mark 50 is in a direction away from the surface 33a of the peripheral portion 33 as it goes in the opposite direction to the forward direction DR1 of the laser beam LB1. When tilted (angle θ °), the air AR present in the gap between the peripheral edge portion 33 of the reversing plate 30 and the step portion 45 of the rivet 40 is the front side in the forward direction DR1 (scanning direction) of the laser beam LB1. However, the pressed air is likely to be released to the outside along the slope of the melting boundary side surface 50a (in the direction of arrow A in the figure). As a result, rapid heating of the air AR existing in the gap between the peripheral edge 33 of the reversing plate 30 and the stepped portion 45 of the rivet 40 is reduced, and the molten metal (mainly the peripheral edge 33 of the reversing plate 30) is ruptured. Can be avoided.

  As shown in FIG. 12, even if the blow hole BH1 is formed by the rupture of the molten metal, the blow hole BH1 is formed on the front side in the forward direction DR1 (scanning direction) of the laser beam LB1. Therefore, after that, the laser beam LB1 passes through the blow hole BH1, so that the blow hole BH1 can be closed as shown in FIG. As a result, it is possible to improve the quality of welding, the current interrupting device, and the reliability of the secondary battery using the current interrupting device.

(Example)
With reference to FIGS. 14 to 17, an example of the current interrupting device in the present embodiment will be described. FIG. 14 is an enlarged cross-sectional view taken along the forward (scanning) direction when the laser beam is irradiated in the embodiment. FIG. 15 is along the forward (scan) direction when the laser beam is irradiated in the embodiment. FIG. 16 is an enlarged cross-sectional view, FIG. 16 is a cross-sectional view taken along the forward (scanning) direction at the time of laser beam irradiation in the comparative example, and FIG. 17 is an intersection in Example 1-5 and Comparative Example 1-2. It is a figure which shows the relationship between an angle, the number of airtight defects, and the number of blow holes.

  In this example, aluminum (A1050) having a thickness of 0.3 mm was used for the reversing plate 30. The rivet 40 is made of aluminum (A1050) having a thickness of 1.0 mm. The outer diameter of the peripheral portion 33 and the inner diameter (diameter) of the stepped portion 45 are 18 mm.

  The first welding marks 50 as the temporarily fixed welding were formed at four locations at a 90 ° pitch on the circumference. The incident angle of the laser beam for temporary fixing welding (see FIG. 7, θ2) is the intersection angle (θ) between the melting boundary lower surface 60s and the melting boundary side surface 50a of the second welding mark 60 shown in the table of FIG. Adjusted. The conditions of the laser beam LB1 are an output of 1200 W, a processing speed of 300 mm / sec, and a beam diameter (irradiation part) of 80 μm.

  Twenty-five current interrupting devices shown in the above embodiment were created, and airtightness was confirmed by He leak inspection (the number of confidential failures in 25), and appearance of blowholes was confirmed (in 100 locations) Frequency of occurrence).

  As shown in FIG. 17, the case where the crossing angle (θ) between the melting boundary lower surface 60 s of the second welding mark 60 and the melting boundary side surface 50 a is 80 ° is Example 1, and the case of 60 ° is Example 2, 50 °. The case of Example 3 was designated as Example 3, the case of 30 ° was designated as Example 4, and the case of 20 ° was designated as Example 5. Moreover, as a comparative example, the case where the crossing angle (θ) is 135 ° is referred to as Comparative Example 1, and the case where it is 90 ° is referred to as Comparative Example 2.

  Referring to FIG. 14, in the case of Example 1 (θ = 80 °), the number of airtight defects was 0 out of 25. The number of blowholes was 1 out of 100. Therefore, it was confirmed that the welding quality and the reliability as the current interrupting device were obtained.

  In the case of Example 2 (θ = 60 °), the number of airtight defects was 0 out of 25. The number of blow holes was 0 out of 100. Also in Example 3 (θ = 50 °), the number of airtight defects was 0 out of 25. The number of blow holes was 0 out of 100. Therefore, it was confirmed that the quality of welding and the reliability as a current interrupting device were sufficiently obtained.

  In Example 4 (θ = 30 °), the number of airtight defects was 1 out of 25. The number of blow holes was 0 out of 100. Therefore, it was confirmed that the welding quality and the reliability as the current interrupting device were obtained.

  Referring to FIG. 15, in Example 5 (θ = 20 °), the number of airtight defects was 8 out of 25. The number of blow holes was 0 out of 100. It is considered that the quality of welding and the reliability as a current interrupting device are the limits. If θ is less than 30 °, the incident angle of the laser beam at the time of forming the first welding mark 50 is also reduced, so that the welding depth needs to be increased. As a result, it is considered that thermal deformation increases and the number of airtight defects tends to increase.

  Comparative Example 1 is a case where θ = 135 °, and the cross-sectional shape of the first welding mark 50 is the shape shown in FIG. 9. In this case, the number of airtight defects was 18 out of 25. The number of blowholes was 31 out of 100. Therefore, it has been confirmed that the quality of welding and the reliability as a current interrupting device are insufficient.

  Referring to FIG. 16, Comparative Example 2 is a case where θ = 90 °, and in this case, the number of airtight defects was 6 out of 25. The number of blow holes was 10 out of 100. Therefore, it has been confirmed that the quality of welding and the reliability as a current interrupting device are insufficient.

  From the above results, in a cross-sectional view along the laser beam advance direction DR1, the melting boundary side surface 50a on the laser beam LB1 side of the first welding mark 50 is directed in the opposite direction to the laser beam LB1 advance direction DR1. Therefore, it is preferable to incline in the direction away from the surface 33a of the peripheral edge portion 33.

  In particular, the crossing angle (θ) between the melting boundary lower surface 60s of the second welding mark 60 and the melting boundary side surface 50a is preferably 30 ° or more and 80 ° or less, and further, the melting boundary lower surface 60s of the second welding mark 60. It can be said that the crossing angle between the melt boundary side surface 50a is preferably 50 ° or more and 60 ° or less.

  As mentioned above, although embodiment and the Example based on this invention were described, the content disclosed this time is an illustration and restrictive at no points. The technical scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 10 exterior body, 11 accommodating part, 12 sealing board, 12H through-hole, 13 electrode body (battery element), 14 positive electrode core exposed part, 15 negative electrode core exposed part, 16, 17, 18 gasket, 19 electrically conductive plate, 20 , 24 External terminal, 21, 25 Current collecting terminal, 21L, 21R Flat plate part, 22 Thick part, 23 Thin part, 23H Through hole, 23G Annular groove, 30 Inversion plate (diaphragm), 31 Top surface part (reversal part), 32 inclined portion, 33 peripheral edge portion, 33a surface, 40 rivets, 41 caulking portion, 42 small diameter portion, 43 connecting portion, 44 large diameter portion, 45 step portion, 45a step, 50 first welding mark, 50a melting boundary side surface, 60 2nd welding trace, 60 s melting boundary lower surface, 100 secondary battery.

Claims (7)

A current interrupting device for interrupting a current flow between the battery element and an external terminal provided outside the exterior body when the internal pressure of the exterior body containing the battery element rises;
A circular reversal plate that blocks conduction between the battery element and the external terminal by reversing when the internal pressure of the exterior body rises,
A rivet having an annular step portion that is electrically connected to the external terminal and on which a peripheral portion of the reversing plate is placed;
A plurality of first welding marks in which welding is performed on a plurality of selected regions at the butt portion between the stepped portion and the peripheral portion, and temporary fixing welding is performed,
In the butted portion of the stepped portion and the peripheral edge portion, a second welding mark in which the entire circumference is welded while being advanced while irradiating a laser beam for welding to the entire circumference;
With
In a cross-sectional view along the advancing direction of the laser beam, the melting boundary side surface of the first welding mark on the laser beam side is away from the surface of the peripheral portion as it goes in the opposite direction to the advancing direction of the laser beam. A current interrupting device that is tilted away.   2. The current interrupting device according to claim 1, wherein an intersection angle between the lower surface of the melting boundary of the second welding mark and the side surface of the melting boundary is 30 ° or more and 80 ° or less.   3. The current interrupting device according to claim 2, wherein an angle of intersection between the lower surface of the melting boundary of the second welding mark and the side surface of the melting boundary is 50 ° or more and 60 ° or less. A battery element;
An exterior body that houses the battery element;
4. The current according to claim 1, wherein a current flow between the battery element and an external terminal provided outside the exterior body is interrupted when an internal pressure of the exterior body increases. A shut-off device;
A secondary battery comprising:
The exterior body is
A bottomed cylindrical housing portion having an opening and housing the battery element;
A sealing plate for closing the opening,
The current interrupting device is a secondary battery attached to the sealing plate. A current interrupting device that is used for a secondary battery and interrupts conduction between the battery element and the external terminal by the reversing operation of the circular reversing plate,
Placing the peripheral portion of the reversing plate on the step portion of the rivet that is electrically connected to the external terminal and has an annular step portion on which the peripheral portion of the reversing plate is placed;
In the butt portion between the stepped portion and the peripheral portion, welding is performed to a plurality of selected regions, and a plurality of first welding marks are formed, and a temporary fixing welding step is performed.
An entire circumference welding step of forming a second welding mark by advancing while irradiating a welding laser beam to the entire circumference at the butt portion of the stepped portion and the peripheral edge portion, and
In the all-around welding process,
Manufacturing of a current interrupting device, wherein a melt boundary side surface of the first welding mark on the laser beam side is inclined in a direction away from the surface of the peripheral edge as it goes in a direction opposite to a forward direction of the laser beam. Method.   6. The method of manufacturing a current interrupting device according to claim 5, wherein an intersection angle between the lower surface of the melting boundary and the side surface of the melting boundary of the second welding mark formed by the laser beam irradiation is 30 ° or more and 80 ° or less.   7. The crossing angle between the melting boundary lower surface and the melting boundary side surface of the second welding mark formed by irradiation with the laser beam in the all-around welding step is 50 ° or more and 60 ° or less. A method of manufacturing a current interrupt device.

Images