JP2012130946A - Method of welding case - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, when a laser beam for welding between a lid and a case body is irradiated to the lid and the case body at the same time, a part of the laser beam passes through, without being used for welding, a clearance between the lid and the case body if there is the clearance between them.SOLUTION: A method of welding the case includes: a step of disposing the lid (12) inside an opening (11a) of the case body (11) that accommodates an object (20) in condition that the clearance (CL) is provided for the opening; a step of melting one of an outer edge of the lid and the opening by the irradiation of a first laser beam; a step of melting the another of the outer edge of the lid and the opening by the irradiation of a second laser beam, and bringing it into contact with the one melted part; and a step of further melting the outer melted edges of the lid and the opening by the irradiation of a third laser beam.

Description

  The present invention relates to a case main body and a welding method for fixing a lid.

  A secondary battery (unit cell) is generally composed of a power generation element that charges and discharges and a case that houses the power generation element. The case is constituted by at least two members in order to accommodate the power generation element. Specifically, a case of a secondary battery can be configured by a case main body having an opening for accommodating the power generation element and a lid for closing the opening of the case main body.

  The lid is fixed to the opening of the case body, and the inside of the case is hermetically sealed. As a method for fixing the lid and the case main body, if the lid and the case main body are made of metal, welding can be performed. Specifically, the lid and the case main body can be melted and joined by irradiating the lid and the case main body with laser light.

JP 2001-338622 A JP 2007-207453 A

  When welding the lid and the case body, the lid and the case body can be simultaneously melted and bonded by irradiating the lid and the case body simultaneously with laser light. However, when a clearance is provided between the lid and the case body, the laser light passes through the clearance. The laser beam that has passed through the clearance is not used for welding the lid and the case body, and is wasted.

  The case welding method according to the first invention of the present application includes a step of arranging a lid inside the opening of the case main body that accommodates the object, with a clearance provided for the opening. A step of melting one of the outer edge and the opening of the lid by irradiation of the first laser beam; and a step of melting the other of the outer edge and the opening of the lid by irradiation of the second laser beam, Contacting. Furthermore, it has the step which further melts the outer edge and opening part of the lid | cover in a molten state by irradiation of a 3rd laser beam.

  Here, the first laser beam, the second laser beam, and the third laser beam can be irradiated in different periods. Further, the first laser beam, the second laser beam, and the third laser beam can be irradiated simultaneously. If three types of laser beams are irradiated simultaneously, the lid and the opening can be welded by one irradiation process.

  The diameters of the third laser light reaching the lid and the opening can be made larger than the diameters of the first laser light and the second laser light reaching the lid and the opening, respectively. Thereby, when the lid and the opening in the molten state are further melted, the melting region can be expanded. By melting a wide area, the strength of the welded portion of the lid and the opening can be ensured.

  A third laser beam having an energy density higher than that of the first laser beam and the second laser beam can be used. Thereby, the penetration depth of a lid | cover and an opening part can be ensured, and the intensity | strength of the welding part of a lid | cover and an opening part can be ensured. On the other hand, the inner wall surface of the case body can be configured as a flat surface. Thereby, a case main body can be set as a simple structure.

  The case welding method according to the second invention of the present application includes a step of placing a lid inside the opening of the case main body that accommodates the object. The step of melting the contact portion of the opening and the lid by irradiation with the first laser light and the second laser light having a higher energy density than the first laser light are applied to the opening and the lid in the molten state. Irradiating and melting.

  According to the second invention of the present application, it is possible to ensure the penetration depth when welding the opening and the lid, and it is possible to ensure the strength of the welded portion of the opening and the lid.

  Here, the diameter of the second laser light reaching the opening and the lid can be made smaller than the diameter of the first laser light reaching the opening and the lid. Thereby, the energy density of the second laser light when reaching the opening and the lid can be made higher than the energy density of the first laser light when reaching the opening and the lid. If the second laser beam is focused on one point on the surface of the opening and the lid, the energy density of the second laser beam can be maximized.

  In the first and second inventions of the present application, as the object, a power generation element that is provided inside the secondary battery and performs charging and discharging can be used.

  3rd invention of this application is a manufacturing method of the electrical storage element by which the electric power generation element which charges / discharges was accommodated in the case main body, and the opening part of the case main body was block | closed with the lid | cover, Comprising: The step which accommodates an electric power generation element in a case main body And a step of disposing a lid inside the opening with a clearance provided for the opening. A step of melting one of the outer edge and the opening of the lid by irradiation of the first laser beam; and a step of melting the other of the outer edge and the opening of the lid by irradiation of the second laser beam, And a step of further melting the outer edge and the opening of the lid in a molten state by irradiation with a third laser beam.

  According to the third aspect of the present invention, it is possible to prevent the laser light from passing through the clearance between the opening and the lid and reaching the power generating element. Further, it is possible to irradiate the opening portion and the welded portion of the lid without waste.

  4th invention of this application is a manufacturing method of the electrical storage element by which the electric power generation element which charges / discharges was accommodated in the case main body, and the opening part of the case main body was block | closed with the lid | cover, Comprising: The step which accommodates an electric power generation element in a case main body And a step of disposing a lid inside the opening. The step of melting the contact portion of the opening and the lid by irradiation with the first laser light and the second laser light having a higher energy density than the first laser light are applied to the opening and the lid in the molten state. Irradiating and melting.

  According to the fourth invention of the present application, it is possible to ensure the penetration depth when welding the opening and the lid, and it is possible to ensure the strength of the welded portion (storage element) of the opening and the lid.

  According to the first invention of the present application, it is possible to prevent the laser light from passing through the clearance between the opening and the lid. And a laser beam can be irradiated to a welding part of an opening part and a lid without waste.

1 is an external view of a secondary battery in Example 1. FIG. 2 is a diagram showing an internal structure of a secondary battery in Example 1. It is an expanded view of the electric power generation element in Example 1. FIG. In Example 1, it is the schematic which shows the irradiation system of a laser beam. In Example 1, it is a figure which shows the process which melt | dissolves a lid | cover by irradiation of a laser beam. In Example 1, it is a figure which shows the process which melts a case main body by irradiation of a laser beam. In Example 1, it is a figure which shows the process which increases the fusion | melting part of a cover and a case main body by irradiation of a laser beam. In Example 2, it is a figure which shows the irradiation pattern of three types of laser beams. In the modification of Example 2, it is a figure which shows the irradiation pattern of three types of laser beams. In Example 3, it is a figure which shows the state which irradiated the 1st laser beam with respect to the lid | cover and the case main body. In Example 3, it is a figure which shows the state which irradiated the 2nd laser beam with respect to the lid | cover and the case main body. It is a figure which shows the state which irradiated only the 2nd laser beam with respect to the lid | cover and the case main body.

  Examples of the present invention will be described below.

  A case manufacturing method (welding method) that is Embodiment 1 of the present invention will be described. The case in the present embodiment is used as a case constituting an exterior of a secondary battery (corresponding to a storage element). First, the structure of the secondary battery will be described with reference to FIGS. FIG. 1 is an external view of a secondary battery, and FIG. 2 is a diagram showing an internal structure of the secondary battery.

  As the secondary battery 1, for example, a nickel metal hydride battery or a lithium ion battery can be used. Moreover, an assembled battery can be comprised using the some secondary battery 1, and an assembled battery can be mounted in a vehicle. Vehicles include hybrid cars and electric cars. A hybrid vehicle is a vehicle that generates travel energy using an assembled battery and a fuel cell or an internal combustion engine, and an electric vehicle is a vehicle that generates travel energy using only the assembled battery.

  The secondary battery 1 includes a case 10 and a power generation element 20 accommodated in the case 10. The case 10 has a case body 11 and a lid 12 made of metal (for example, aluminum). The case body 11 forms a space for accommodating the power generation element 20 and has an opening 11a. The opening 11 a is used when the power generation element 20 is incorporated into the case body 11.

  The case body 11 includes a bottom surface and two sets of side surfaces facing each other. Further, the inner wall surface of the case body 11 is a flat surface.

  The lid 12 is disposed at a position that closes the opening 11 a of the case body 11. Here, the lid 12 is disposed so as to be located inside the opening 11a. That is, the outer edge of the lid 12 is located inside the opening 11 a and faces the inner wall surface of the case body 11. A clearance is provided between the opening 11a and the lid 12 so that the lid 12 can be easily arranged inside the opening 11a. If the sizes of the lid 12 and the case main body 11 are set so that there is no clearance, it is difficult to attach the lid 12 to the opening 11 a of the case main body 11.

  The lid 12 and the opening 11a are welded, whereby the inside of the case 10 is in a sealed state. A method for welding the lid 12 and the opening 11a will be described later.

  A positive electrode terminal 31 and a negative electrode terminal 32 are fixed to the lid 12. The lid 12 is provided with a safety valve 33, and the safety valve 33 is located between the positive terminal 31 and the negative terminal 32. The safety valve 33 is used to discharge gas generated inside the case 10 to the outside of the case 10.

  The power generation element 20 is an element that can be charged and discharged. As shown in FIG. 3, the power generation element 20 includes a positive electrode element 21, a negative electrode element 22, and a separator (including an electrolytic solution) 23 disposed between the positive electrode element 21 and the negative electrode element 22. The positive electrode element 21 includes a current collector plate 21a and a positive electrode active material layer 21b formed on the surface of the current collector plate 21a. The positive electrode active material layer 21b is formed on both surfaces of the current collector plate 21a, and the positive electrode active material layer 21b is not formed in a part of the current collector plate 21a. The positive electrode active material layer 21b contains a positive electrode active material, a conductive agent, a binder, and the like.

  The negative electrode element 22 includes a current collector plate 22a and a negative electrode active material layer 22b formed on the surface of the current collector plate 22a. The negative electrode active material layer 22b is formed on both surfaces of the current collector plate 22a, and the negative electrode active material layer 22b is not formed in a part of the current collector plate 22a. The negative electrode active material layer 22b contains a negative electrode active material, a conductive agent, a binder, and the like. The current collector plates 21a and 22a can be formed of a metal such as aluminum or copper.

  The positive electrode element 21, the negative electrode element 22, and the separator 23 are laminated as shown in FIG. 3, and the laminated body is wound to obtain the power generation element 20 shown in FIG. In FIG. 2, a region A of the power generation element 20 is a region where the positive electrode active material layer 21b and the negative electrode active material layer 22b overlap each other.

  At one end of the power generation element 20 shown in FIG. 2 (on the left side of the region A), there is a region where only the current collector plate 21a of the positive electrode element 21 is wound, in other words, a region where the positive electrode active material layer 21b is not formed. At the other end of the power generation element 20 shown in FIG. 2 (on the right side of the region A), there is a region where only the current collector plate 22a of the negative electrode element 22 is wound, in other words, a region where the negative electrode active material layer 22b is not formed. .

  As shown in FIG. 2, the current collecting plate 21 a (positive electrode element 21) located at one end of the power generation element 20 is electrically connected to the positive electrode terminal 31 through the positive electrode tab 24. The positive electrode tab 24 is welded to the current collector plate 21 a and is also welded to the positive electrode terminal 31. The current collector plate 22 a (negative electrode element 22) located at the other end of the power generation element 20 is electrically connected to the negative electrode terminal 32 via the negative electrode tab 25. The negative electrode tab 25 is welded to the current collector plate 22 a and is also welded to the negative electrode terminal 32.

  In the present embodiment, the power generation element 20 is configured by winding a laminated body of the positive electrode element 21, the negative electrode element 22, and the separator 23, but is not limited thereto. Specifically, the power generation element 20 may have a configuration in which the positive electrode element 21, the negative electrode element 22, and the separator 23 are simply stacked.

  Next, a method for manufacturing the secondary battery 1 will be briefly described.

  First, as described above, the power generation element 20 is prepared, and the power generation element 20 is accommodated in the case body 11. Then, the lid 12 is welded to the opening 11 a of the case body 11. After the inside of the case 10 is sealed, the inside of the case 10 is filled with the electrolytic solution, and then the filling port of the electrolytic solution formed in the case 10 is closed. Thereby, the secondary battery 1 is obtained.

  Next, the process which welds the case main body 11 and the lid | cover 12 is demonstrated. In this embodiment, the case body 11 and the lid 12 are welded by irradiating the case body 11 and the lid 12 with laser light. As shown in FIG. 4, the laser irradiation apparatus 100 irradiates the case main body 11 and the lid 12 with laser light L. In the configuration shown in FIG. 4, the laser irradiation apparatus 100 is fixed, and the laser irradiation apparatus 100 changes the irradiation direction of the laser light L to change the laser light L to the welded portion of the case body 11 and the lid 12. Is reaching.

  The laser irradiation apparatus 100 can be composed of a light source and an optical system that collects light emitted from the light source. Here, by changing the focal length of the optical system, the diameter of the laser light L reaching the case main body 11 and the lid 12 can be changed. Thereby, the laser beam L can be reached only in a desired region. As a configuration for changing the focal length of the optical system, a configuration in which some lenses in the optical system are moved in the optical axis direction, or a configuration in which some lenses in the optical system are switched can be used. .

  In this embodiment, the laser irradiation apparatus 100 is fixed, but the laser irradiation apparatus 100 can also be moved. Specifically, the laser beam L can be irradiated while moving the laser irradiation apparatus 100 in a two-dimensional plane parallel to the lid 12.

  Next, a method for irradiating the laser beam L will be described with reference to FIGS. 5 to 7 are enlarged views showing a welded portion of the case main body 11 and the lid 12. As shown in FIGS. 5 to 7, a groove 12a is formed on the outer surface of the lid 12, and a region R located on the outer edge side of the lid 12 with respect to the groove 12a is a welded portion. CL shown in FIG. 5 indicates the clearance between the lid 12 and the case body 11.

  First, the laser irradiation apparatus 100 irradiates the region R of the lid 12 with the laser light L as shown in FIG. Here, since the laser irradiation apparatus 100 can adjust the diameter of the laser light L as described above, the laser light L can reach only the region R of the lid 12. By forming the groove 12a in the lid 12 and providing the region R, the laser light L can be concentrated in the region R, and the region R can be efficiently melted.

  Since the region R of the lid 12 is formed along the outer edge of the lid 12, the laser irradiation apparatus 100 moves the laser light L along the outer edge of the lid 12. By irradiating the region R of the lid 12 with the laser light L, the region R of the lid 12 can be melted. If the region R of the lid 12 is melted, the melted portion of the lid 12 can be brought close to the case main body 11, and the clearance CL between the lid 12 and the case main body 11 can be reduced.

  Next, the laser irradiation apparatus 100 irradiates the case main body 11 with the laser light L as shown in FIG. As described above, the laser irradiation apparatus 100 can cause the laser light L to reach only the case body 11. Then, the laser irradiation apparatus 100 moves the laser light L along the opening 11 a of the case body 11. Thereby, the upper part of the case body 11 can be melted, and the melted part of the case body 11 can be brought into contact with the melted part of the lid 12.

  Next, as shown in FIG. 7, the laser irradiation apparatus 100 irradiates the molten portion of the lid 12 and the molten portion of the case body 11 with the laser light L. In the present embodiment, the diameter of the laser beam L irradiated in FIG. 7 is larger than the diameter of the laser beam L irradiated in FIGS. The diameter of the laser beam L here is the diameter of the laser beam L when it reaches the case body 11 or the lid 12.

  By irradiating the melted portions of the lid 12 and the case body 11 with the laser beam L, the melted portions of the lid 12 and the case body 11 can be increased, and the lid 12 and the case body 11 can be welded. In the irradiation process of the laser beam L shown in FIG. 7, the melted portion of the lid 12 and the melted portion of the case body 11 are in contact with each other, so that the laser beam L is prevented from passing through the clearance between the lid 12 and the case body 11. can do.

  The irradiation state shown in FIG. 7 reaches the melted portion of the lid 12 and the case main body 11 in a state before the laser beam L is focused on one point, but is not limited thereto. Specifically, the laser beam L can be condensed at one point on the surface of the melted portion of the lid 12 and the case body 11. As the laser beam L is condensed, the energy density can be increased, and the penetration depth of the lid 12 and the case body 11 can be increased.

  Here, the entire melted portion of the lid 12 and the case body 11 is irradiated with the laser light L shown in FIG. The laser beam L in a state of being made can reach the melting portion of the lid 12 and the case body 11.

  In the laser beam L irradiation method described with reference to FIGS. 5 to 7, the laser beam L is irradiated to the case body 11 after the lid 12 is irradiated with the laser beam L. However, the present invention is not limited to this. Specifically, after the case body 11 is irradiated with the laser light L, the lid 12 can be irradiated with the laser light L.

  According to the present embodiment, since the lid 12 and the case body 11 are melted and the melted portions are brought into contact with each other, the melted portion of the lid 12 and the case body 11 is irradiated with the laser light L. It is possible to prevent the light L from passing through the clearance between the lid 12 and the case body 11. Thereby, it is possible to prevent the laser light L from reaching the power generation element 20 accommodated in the case 10.

  When the laser beam L is simultaneously applied to the lid 12 and the case main body 11, a part of the laser light L passes through the clearance between the lid 12 and the case main body 11. In this case, part of the laser beam L is not used for welding, and the energy of the laser beam L is wasted. On the other hand, in the present embodiment, the laser beam L can be irradiated to the lid 12 and the case body 11 without waste.

  Here, it is conceivable to appropriately set the shape of the inner wall surface of the case body 11 so that the laser light L does not enter the case 10. In this case, the processing of the case body 11 becomes complicated. In the present embodiment, it is possible to prevent the laser light L from entering the inside of the case 10 while configuring the inner wall surface of the case body 11 as a flat surface.

  In the present embodiment, the case 10 of the secondary battery 1 is described, but the present invention is not limited to this. Specifically, a primary battery or an electric double layer capacitor (capacitor) can be used instead of the secondary battery 1. In the present embodiment, the so-called square secondary battery 1 is described. However, the present invention can be applied to a so-called cylindrical secondary battery. That is, the present invention can be applied when a lid is welded to a cylindrical case body.

  In the present embodiment, the case where the case 10 of the secondary battery 1 is welded has been described, but the present invention is not limited to this. That is, the thing accommodated inside the case 10 is not limited to the power generation element 20. Specifically, the present invention can be applied if the case main body 11 and the lid 12 having the same configuration as in the present embodiment are used.

  A welding method that is Embodiment 2 of the present invention will be described. Here, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In the first embodiment (see FIGS. 5 to 7), the laser beam L is irradiated in three times, but in this embodiment, the number of times of irradiation with the laser beam L is one. Hereinafter, the present embodiment will be specifically described.

  As shown in FIG. 8, the laser irradiation apparatus 100 of the present embodiment irradiates three laser beams L1 to L3 simultaneously. FIG. 8 is a view of the case body 11 and the lid 12 as viewed from above the secondary battery 1.

  The laser beam L1 is applied to the lid 12 and is used for melting the lid 12. The laser beam L <b> 2 is applied to the case main body 11 and is used for melting the case main body 11. The laser beam L3 is applied to the melting portion of the lid 12 by the laser beam L1 and the melting portion of the case body 11 by the laser beam L2, and is used for melting the lid 12 and the case body 11.

  The three laser beams L1 to L3 move in the direction of arrow D while maintaining the positional relationship shown in FIG. That is, the three laser beams L <b> 1 to L <b> 3 move along the opening 11 a of the case body 11. In this embodiment, the laser beams L1 and L2 have the same diameter, and the laser beam L3 has a diameter larger than the diameters of the laser beams L1 and L2. The diameters of the laser beams L1 to L3 can be set as appropriate based on the region to be melted.

  The three laser lights L1 to L3 can be generated by providing three light sources in the laser irradiation apparatus 100. Further, laser light emitted from one light source can be divided into three laser lights L1 to L3.

  In the present embodiment, the laser beams L1 and L2 melt the lid 12 and the case body 11, respectively, so that the melted portion of the lid 12 and the melted portion of the case body 11 can be brought into contact with each other. The clearance CL can be eliminated. Further, by using the laser beam L3, the melted portions of the lid 12 and the case body 11 can be increased. A region M shown in FIG. 8 indicates a region where the lid 12 and the case body 11 are melted.

  According to the present embodiment, the lid 12 and the case body 11 can be welded by one irradiation process by using the three laser beams L1 to L3. Similarly to the first embodiment, the laser beam L1 is irradiated only on the lid 12, and the laser beam L2 is irradiated only on the case main body 11. Therefore, the laser beams L1 and L2 do not pass through the clearance CL. . Further, since the laser beam L3 is irradiated in a state where the lid 12 and the melted portion of the case body 11 are in contact with each other, the laser beam L3 does not enter the case 10.

  In this embodiment, as shown in FIG. 8, the irradiation positions of the laser beams L1 and L2 are adjacent to each other, but the present invention is not limited to this. For example, when a difference occurs in the melting time of the lid 12 and the case body 11, the irradiation positions of the laser beams L1 and L2 can be shifted in the movement direction D as shown in FIG. Specifically, a member having a long melting time can be irradiated with laser light at a timing earlier than a member having a short melting time. In this case, all the laser beams L1 to L3 are shifted from each other in the movement direction D. In the example shown in FIG. 9, the laser beam L2 arrives at an earlier timing than the laser beam L1, but the opposite configuration may be used.

  In the present embodiment, the shapes of the laser beams L1 to L3 reaching the lid 12 and the case body 11 are formed in a circular shape, but the present invention is not limited to this. The shapes of the laser beams L1 to L3 can be set as appropriate. The same applies to the laser beam L described in the first embodiment. If the shapes of the laser beams L1 to L3 are circular, the light emitted from the light source can easily reach the lid 12 and the case body 11 efficiently.

  A welding method that is Embodiment 3 of the present invention will be described. Here, the same members as those described in the first embodiment are denoted by the same reference numerals, and detailed description thereof is omitted. In this embodiment, the welding region (in other words, the penetration depth) of the lid 12 and the case body 11 is increased.

  First, the outer edge (edge) of the lid 12 is brought into contact with the inner wall surface of the case body 11. Then, as shown in FIG. 10, the first laser beam L <b> 4 is irradiated on the contact portion between the lid 12 and the case body 11. Here, the first laser beam L4 reaches the lid 12 and the case main body 11 in a state before being focused on one point.

  By simultaneously irradiating the lid 12 and the case body 11 with the first laser light L4, the lid 12 and the case body 11 can be melted simultaneously. Here, since the first laser light L4 has reached the lid 12 and the case body 11 in a state before being condensed at one point, the energy density of the first laser light L4 at this time is the first laser light. L4 is lower than the energy density when the light is condensed at one point. For this reason, even if the lid 12 and the case main body 11 can be melted, it is difficult to ensure a sufficient penetration depth.

  Therefore, in this embodiment, after the lid 12 and the case body 11 are melted by irradiating the first laser beam L4, the second portion is applied to the melted portion of the lid 12 and the case body 11 as shown in FIG. The laser beam L5 is irradiated.

  The second laser beam L5 is condensed at one point on the surface of the melted portion of the lid 12 and the case body 11. Thus, the second laser beam L5 having the highest energy density can reach the molten portion by condensing the second laser beam L5 on one point on the surface of the molten portion. Thereby, the penetration depth of the lid 12 and the case main body 11 can be ensured in the irradiation direction of the second laser light L5.

  As described above, the welding area of the lid 12 and the case body 11 can be increased by properly using the two laser beams L4 and L5. That is, the strength at the welded portion of the lid 12 and the case body 11 can be improved.

  When only the second laser light L5 is irradiated on the lid 12 and the case main body 11, the area of the second laser light L5 reaching the lid 12 and the case main body 11 tends to be insufficient. That is, the second laser beam L5 has the highest energy density, but the region where the second laser beam L5 reaches is limited.

  In this case, as shown in FIG. 12, even if the lid 12 and the case body 11 can be melted, there is a possibility that the melted portion of the lid 12 and the melted portion of the case body 11 cannot be brought into contact with each other. is there. In particular, if there is a slight clearance between the lid 12 and the case main body 11, it is difficult to bring the molten portion of the lid 12 and the molten portion of the case main body 11 into contact with each other. Thereby, welding of the lid | cover 12 and the case main body 11 will become inadequate.

  On the other hand, even if the irradiation order of the laser beams L4 and L5 is reversed to the irradiation order of the present embodiment, the welding area of the lid 12 and the case main body 11 cannot be increased. That is, when the second laser beam L5 is first irradiated, the cover 12 and the case body 11 are not sufficiently welded as described with reference to FIG. Even if the first laser beam L4 is irradiated in such a state, only the surface portion of the lid 12 and the case main body 11 can be melted, and it is difficult to ensure a sufficient penetration depth.

1: Secondary battery (electric storage element) 10: Case 11: Case body 11a: Opening 12: Lid 12a: Groove 20: Power generation element 21: Positive electrode element 21a: Current collector plate 21b: Positive electrode active material layer 22: Negative electrode element 22a : Current collector plate 22b: Negative electrode active material layer 23: Separator 24: Positive electrode tab 25: Negative electrode tab 31: Positive electrode terminal 32: Negative electrode terminal 33: Safety valve 100: Laser light irradiation devices L, L1 to L5: Laser light CL: Clearance

Claims (12)

Arranging a lid in a state where a clearance is provided for the opening inside the opening of the case main body that accommodates the object;
Melting one of the outer edge of the lid and the opening by irradiation with a first laser beam;
Melting the outer edge of the lid and the other of the opening by irradiation with a second laser beam and bringing it into contact with the one molten portion;
Further melting the outer edge of the lid and the opening in a molten state by irradiation with a third laser beam;
A method for welding a case, comprising:   The case welding method according to claim 1, wherein the first laser beam, the second laser beam, and the third laser beam are irradiated in different periods.   The case welding method according to claim 1, wherein the first laser beam, the second laser beam, and the third laser beam are irradiated simultaneously.   The diameter of the third laser light reaching the lid and the opening is larger than the diameter of the first laser light and the second laser light reaching the lid and the opening, respectively. The method for welding a case according to any one of claims 1 to 3.   4. The case welding method according to claim 1, wherein the third laser light has an energy density higher than that of the first laser light and the second laser light. 5.   6. The case welding method according to claim 1, wherein an inner wall surface of the case body is a flat surface. Placing a lid inside the opening of the case body that houses the object; and
Melting the contact portion of the opening and the lid by irradiation with a first laser beam;
Irradiating and melting the opening and the lid in a molten state with a second laser beam having an energy density higher than that of the first laser beam;
A method for welding a case, comprising:   8. The case according to claim 7, wherein a diameter of the second laser light reaching the opening and the lid is smaller than a diameter of the first laser light reaching the opening and the lid. Welding method.   The case welding method according to claim 8, wherein the second laser light is focused at one point on the surface of the opening and the lid.   The case welding method according to claim 1, wherein the object is a power generation element that is provided inside a secondary battery and performs charging and discharging. A method of manufacturing a power storage element in which a power generation element that performs charging and discharging is housed in a case body, and an opening of the case body is closed with a lid,
Accommodating the power generation element in the case body;
Placing the lid inside the opening with a clearance from the opening; and
Melting one of the outer edge of the lid and the opening by irradiation with a first laser beam;
Melting the outer edge of the lid and the other of the opening by irradiation with a second laser beam and bringing it into contact with the one molten portion;
Further melting the outer edge of the lid and the opening in a molten state by irradiation with a third laser beam;
A method for manufacturing a power storage element, comprising: A method of manufacturing a power storage element in which a power generation element that performs charging and discharging is housed in a case body, and an opening of the case body is closed with a lid,
Accommodating the power generation element in the case body;
Disposing the lid inside the opening;
Melting the contact portion of the opening and the lid by irradiation with a first laser beam;
Irradiating and melting the opening and the lid in a molten state with a second laser beam having an energy density higher than that of the first laser beam;
A method for manufacturing a power storage element, comprising:

Images