JP2014100714A - Closed container and method of manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a closed container capable of easily increasing compressive strength and airtightness, and a method of manufacturing the same.SOLUTION: A case 11 for a secondary battery 10 has an opening S of a metal case body 13 closed with a metal lid body 14. The case 11 has two annular weld zones, that is to say, outside and inside weld zones 42 and 41 by welding from its outside. In a mating part 40, the inside weld zone 41 is positioned inside the case 11 with respect to the outside weld zone 42.

Description

  In the present invention, the opening of the metal case main body is closed with a metal lid, and the case main body and the lid are joined by joining the mating portion of the case side mating surface and the lid side mating surface. The present invention relates to a sealed container and a manufacturing method thereof.

  A vehicle such as an EV (Electric Vehicle) or a PHV (Plug in Hybrid Vehicle) is equipped with a secondary battery such as a lithium ion battery as a power storage device that stores power supplied to an electric motor serving as a prime mover. Further, in a sealed container such as a secondary battery, it is important to increase the pressure resistance because it is not destroyed even if the internal pressure increases, and to increase the airtightness in order to prevent gas leakage.

  For example, a sealed container of a rectangular sealed battery (secondary battery) in Patent Document 1 houses an electrode assembly in a metal battery outer can (case body), and a sealing body (lid body) at an opening of the battery outer can. ). The battery outer body and the sealing body are joined by pulse laser welding, and the pulse laser beam is constituted by a two-stage waveform composed of continuous pulses of a first pulse laser beam and a second pulse laser beam having a rectangular waveform, The peak output value of the first pulse laser beam is set larger than the peak output value of the second pulse laser beam. By forming the welded portion in two layers, the molten metal is replenished from the molten pool to the solidified first layer welded portion when forming the first layer welded portion. Molten metal is supplemented to defective parts such as nests, and airtightness is enhanced. Further, when the second layer weld is formed, a weld having a different crystal grain size and crystal orientation from that of the first layer weld is formed, and the first layer weld is further replaced by the second layer weld. Since the shrinkage force acting on is absorbed, the occurrence of weld cracks in the welded portion can be prevented, and the pressure resistance can be increased.

JP 2011-200155 A

  However, in Patent Document 1, in order to increase the pressure resistance and airtightness, the output peak value of the pulse laser beam is adjusted in two stages to form the welded portion in two layers, and this welded portion is formed. The output adjustment was very troublesome.

  It is an object of the present invention to provide a sealed container and a method for manufacturing the sealed container that can easily improve the pressure strength and the air tightness.

  In order to solve the above-mentioned problem, the sealed container according to claim 1, wherein the opening of the metal case main body is closed with a metal lid, and the case to the lid in the case main body is closed. A sealed container in which an annular mating portion between a side mating surface and a lid side mating surface facing the case side mating surface in the lid is welded to join the case main body and the lid. By welding from the outside of the container, it has two annular welded parts, that is, an outer welded part and an inner welded part, and in the mating part, the inner welded part is more inside the sealed container than the outer welded part. The main point is that

  According to this, when gas is generated in the hermetic container, the gas is suppressed from leaking out of the hermetic container due to the seal by the inner welded portion. In the unlikely event that gas passes through the inner welded portion, the seal by the outer welded portion prevents leakage from the inside of the sealed container through the mating portion. Therefore, the airtightness of the sealed container can be enhanced by the inner welded portion and the outer welded portion. In addition, even if one of the inner welded portion and the outer welded portion is welded with a lower energy density at the time of welding than the other so that a blowhole is not easily formed, the joint strength can be increased by the other welded portion. It is possible to increase the pressure resistance of the sealed container. And a pressure-resistant strength and airtightness can be easily raised only by forming an inner side weld part and an outer side weld part in an airtight container.

Moreover, it is preferable that the said inner side weld part is shallower than the said outer side weld part about the welding depth from the outer surface of the said airtight container.
According to this, for example, when the inner welded portion and the outer welded portion are formed by laser welding, in the inner welded portion, the energy density of the irradiated laser beam is made smaller than that of the outer welded portion so that the penetration depth is shallow. . For this reason, generation | occurrence | production of a blowhole is suppressed in an inner side welding part. Therefore, it is difficult to form a blow hole in the inner welded portion that first shuts off gas leakage from the inside of the sealed container, thereby ensuring airtightness more reliably. On the other hand, since the outer welded portion is formed with deeper penetration than the inner welded portion, it is possible to ensure high joint strength.

  The inner welded portion and the outer welded portion may be formed by laser welding, and the depth direction of at least one of the inner welded portion and the outer welded portion may be formed along the mating portion.

  According to this, the depth direction of the welded portion, that is, the case side mating surface and the lid side mating surface along the optical axis of the laser beam are welded extensively, for example, in the direction intersecting the mating portion, the inner welded portion And compared with the case where an outer side welding part is extended, airtightness and pressure-resistant strength can be improved.

Further, the depth direction of the outer welded portion may be formed along the mating portion.
According to this, since the outer welded portion is formed along the mating portion, the mating portion can be reliably joined by the outer welded portion, and the pressure resistance strength of the sealed container can be ensured.

  The mating portion includes an inner mating portion positioned inside the sealed container, and an outer mating portion bent with the inner mating portion and positioned outside the sealed container, and the depth of the inner welded portion. A vertical direction and a depth direction of the outer welded portion may be formed along the inner mating portion and the outer mating portion, respectively.

  According to this, the inner welded portion is formed by irradiating laser light from the outer surface of the sealed container toward the inner mating portion at a position different from the outer mating portion. On the other hand, the outer welded portion is formed by irradiating a laser beam from the outer surface of the sealed container toward the outer mating portion. That is, the welded portion is formed by irradiating two places of the sealed container with laser light. Therefore, in order to form a welded part, it is easier to form a welded part than when a laser beam is irradiated to one place and the energy density is changed to form an outer welded part and an inner welded part. Can do.

  The manufacturing method of the airtight container of Claim 6 is a manufacturing method of the airtight container which joins the joint part of the metal case main body which has an opening part, and the metal lid body which obstruct | occludes the said opening part, , Irradiating a laser beam from the outside of the sealed container to form two annular welds on the mating part, the two annular welds being more than the outer weld and the outer weld. An inner welded portion located inside the sealed container, wherein the energy density of the laser beam when forming the inner welded portion is smaller than the energy density of the laser beam when forming the outer welded portion. Is the gist.

  According to this, the penetration depth becomes shallow in the inner welded portion, and the occurrence of blowholes is suppressed in the inner welded portion. Even if gas passes through the inner welded portion, it is prevented from leaking from the inside of the sealed container through the mating portion by the seal by the outer welded portion. Therefore, it is difficult for a blowhole to be formed in the inner welded portion that first shuts off gas leakage from the sealed container, and the outer welded part is further provided on the outer side, thereby ensuring the airtightness of the sealed container.

  Moreover, even if the inner welded part is welded with a lower energy density during welding than the outer welded part so that blowholes are not easily formed, the outer welded part can increase the joint strength, and the pressure resistance of the sealed container can be increased. Can be increased.

  The closed container manufacturing method according to claim 7 is a closed container manufacturing method in which a joint portion between a metal case main body having an opening and a metal lid closing the opening is joined. And forming two annular welds on the mating part from the outside of the sealed container, the welded part being located on the inside of the sealed container with respect to the outer welded part and the outer welded part The gist is to form the inner welded portion in the mating portion by laser welding and the outer welded portion by friction stir welding.

  According to this, since the outer welded portion is joined by friction stir welding, even if frictional heat is generated, it is difficult to reach a high temperature, and since the penetration depth is shallow, the formation of blowholes at the outer joined portion is prevented. Is done. Therefore, gas leakage from the inside of the sealed container can be suppressed by the inner welded portion, and can be reliably prevented at the outer joint portion where no blowhole is formed, thereby improving the airtightness of the sealed container. In addition, by providing the inner welded portion and the outer joint portion, the outer joint portion can be sealed with the inner welded portion as a whole even if the outer joint portion has a weaker joint strength than the inner welded portion so that the blowhole is not formed. It is possible to increase the bonding strength.

Further, at least one of the inner welded portion and the outer welded portion may be laser-welded with the laser beam along the mating portion.
According to this, the depth direction of the welded portion, that is, the case side mating surface and the lid side mating surface along the optical axis of the laser beam are welded extensively, for example, in the direction intersecting the mating portion, the inner welded portion And compared with the case where an outer side welding part is extended, airtightness and pressure-resistant strength can be improved.

The outer welded portion may be laser-welded with the laser beam along the mating portion.
According to this, since the outer welded portion is formed along the mating portion, the mating portion can be firmly welded to ensure the compressive strength.

  The mating portion includes an inner mating portion positioned inside the sealed container and an outer mating portion bent with the inner mating portion and positioned outside the sealed container to form the inner welded portion. The laser beam and the laser beam forming the outer welded portion may be laser welded along the inner mating portion and the outer mating portion, respectively.

  According to this, the inner welded portion is formed by irradiating laser light from the outer surface of the sealed container toward the inner mating portion at a position different from the outer mating portion. On the other hand, the outer welded portion is formed by irradiating a laser beam from the outer surface of the sealed container toward the outer mating portion. Therefore, the welded part is formed by irradiating two places of the sealed container with laser light. Therefore, in order to form a welded part, it is easier to form a welded part than when a laser beam is irradiated to one place and the energy density is changed to form an outer welded part and an inner welded part. Can do.

  According to the present invention, the pressure strength and airtightness can be easily increased.

The perspective view which shows the external appearance of the secondary battery of embodiment. The disassembled perspective view which shows a secondary battery. (A) is a figure which shows the state which performs a laser welding while showing a case side mating surface, a cover body side mating surface, and a mating part, (b) is a figure which shows an inner side welding part and an outer side welding part. (A) is a figure which shows the case side mating surface of another example, a cover body side mating surface, and a mating part, (b) is a figure which shows an inner side welding part and an outer side welding part. (A) is a figure which shows the case side mating surface of another example, a cover body side mating surface, and a mating part, (b) is a figure which shows an inner side welding part and an outer side welding part. The figure which shows an inner side welding part and an outer side welding part.

Hereinafter, an embodiment embodied in a secondary battery will be described with reference to FIGS.
As shown in FIGS. 1 and 2, in the secondary battery 10, an electrode assembly 12 is accommodated in a case 11 as a sealed container. The case 11 includes a rectangular parallelepiped case main body 13 having an opening S, and a rectangular flat plate-shaped lid body 14 that closes the opening S of the case main body 13. Both the case main body 13 and the lid body 14 are made of metal (for example, stainless steel or aluminum). Further, the secondary battery 10 of the present embodiment is a prismatic battery whose appearance is square. Further, the secondary battery 10 of the present embodiment is a lithium ion battery.

  A positive electrode terminal 15 and a negative electrode terminal 16 are electrically connected to the electrode assembly 12 accommodated in the case 11. The positive electrode terminal 15 and the negative electrode terminal 16 are each attached with a ring-shaped insulating ring 17 a for insulating from the case 11. Further, the positive electrode terminal 15 and the negative electrode terminal 16 are exposed outside the case 11 from the lid body 14.

  The electrode assembly 12 includes a positive electrode, a negative electrode, and a separator that insulates the positive electrode from the negative electrode. The positive electrode is configured by applying a positive electrode active material to both surfaces of a positive metal foil (aluminum foil). The negative electrode is configured by applying a negative electrode active material to both surfaces of a negative electrode metal foil (copper foil). The electrode assembly 12 has a stacked structure in which a plurality of positive electrodes and a plurality of negative electrodes are alternately stacked and a separator is interposed between the electrodes.

The welding structure of the case body 13 and the lid body 14 will be described in detail.
First, the configuration of the case body 13 and the lid body 14 will be described.
As shown in FIGS. 1 and 3A, the case main body 13 has a bottomed rectangular tube shape, and has a rectangular flat plate-shaped bottom wall 13a and a rectangular tube shape standing from four sides of the bottom wall 13a. And a peripheral wall 13b. The direction perpendicular to the inner and outer surfaces of the bottom wall 13a of the case body 13 and the peripheral wall 13b standing from the bottom wall 13a is defined as the axial direction of the case body 13. In the peripheral wall 13 b, the tip surface opposite to the bottom wall 13 a side is a support surface 13 c that supports the lid body 14. The support surface 13c has a flat surface shape orthogonal to the axial direction of the peripheral wall 13b and parallel to the inner surface of the bottom wall 13a. Further, the inner peripheral surface and the outer peripheral surface 13d of the peripheral wall 13b are flat surfaces extending orthogonally to the support surface 13c and parallel to the axial direction.

  The lid body 14 has a rectangular flat plate-shaped lid body 20, a rectangular plate-shaped insertion portion 21 that protrudes from the inner surface of the lid body 20 on the case body 13 side and is slightly smaller than the outer circumferential surface of the lid body 20, Have In the lid main body 20, a portion that is the outer peripheral portion and extends outward from the periphery of the insertion portion 21 is a flange portion 22.

  In the lid body 14, the insertion portion 21 is inserted into the peripheral wall 13b, and the flange portion 22 is supported by the support surface 13c of the peripheral wall 13b. The outer peripheral surface 22b of the flange part 22 and the outer peripheral surface 13d of the peripheral wall 13b are located on the same plane. In the flange portion 22, an annular surface supported by the support surface 13c of the case body 13 is defined as a supported surface 22a. The supported surface 22a is flat. The outer peripheral surface of the insertion portion 21 is a lid-side facing surface 21a that faces the inner peripheral surface of the peripheral wall 13b, and the inner peripheral surface of the peripheral wall 13b that faces the lid-side facing surface 21a is the case side. Let it be the facing surface 13e.

  The supported surface 22a and the lid-side facing surface 21a are the lid-side mating surface 14f facing the case body 13, and the supporting surface 13c and the case-side facing surface 13e are the case-side mating surface 13f facing the lid-side mating surface 14f. It is. The support surface 13c and the supported surface 22a are abutted against each other to form the outer mating portion 31, and the case-side facing surface 13e and the lid-side facing surface 21a are abutted to each other to configure the inner mating portion 32. The outer mating portion 31 and the inner mating portion 32 constitute a mating portion (butting surface) 40 that bends between them.

  The mating portion 40 composed of the case side mating surface 13f and the lid side mating surface 14f is in surface contact with the mutually facing surfaces, and is provided in an annular shape over the entire circumference of the case 11. The case body 13 and the lid body 14 are integrated by joining the mating portion 40 by laser welding.

  As shown in FIG. 3 (b), in the mating portion 40, by welding from the outside of the case 11, an annular welded portion between the outer welded portion 42 and the inner welded portion 41 located on the inner side of the case 11 than that. It is joined by two welds. The inner welded portion 41 joins a part of the lid-side facing surface 21a of the insertion portion 21 and a part of the case-side facing surface 13e of the peripheral wall 13b, and joins the inner mating portion 32. The inner welded portion 41 reaches the lid-side facing surface 21a and the case-side facing surface 13e from the outer surface 14c of the lid body 14, and the welding depth of the inner welded portion 41 is F1. Moreover, in the inner side welding part 41, let the nugget diameter in the outer surface 14c of the cover body 14 be R1. The outer welded portion 42 joins the support surface 13c and the supported surface 22a, and joins the outer mating portion 31. The welding depth F2 of the outer welded portion 42 is deeper than the weld depth F1 of the inner welded portion 41. In the outer welded portion 42, the maximum value of the nugget diameter R <b> 2 straddling the outer peripheral surface 22 b of the flange portion 22 and the outer peripheral surface 13 d of the peripheral wall 13 b is slightly smaller than the maximum value of the nugget diameter R <b> 1 of the inner welded portion 41.

  The ratio (F1 / R1) of the welding depth F1 to the nugget diameter R1 in the inner welded portion 41 is smaller than the ratio (F2 / R2) of the welding depth F2 to the nugget diameter R2 in the outer welded portion 42. This indicates that, for example, when the nugget diameters R1 and R2 are substantially the same in the inner welded portion 41 and the outer welded portion 42, the inner welded portion 41 has a shallower weld depth F1.

Next, a method for manufacturing the case 11 will be described.
First, the electrode assembly 12 is accommodated in the case body 13 through the opening S of the case body 13. Next, as shown in FIG. 3 (a), the support surface 13c of the peripheral wall 13b supports the supported surface 22a of the lid body 14, and the insertion portion 21 is inserted into the case body 13 to form the case side mating surface 13f. And the lid-side mating surface 14f face each other to form the mating portion 40.

  Next, the inner side welding part 41 and the outer side welding part 42 are formed. The inner welded portion 41 is formed by irradiating the laser beam L from the outside of the case 11 with the optical axis (irradiation direction) of the laser beam L along the inner matching portion 32. When the inner welded portion 41 is formed, the energy density of the laser beam L is suppressed, the penetration depth (welding depth F1) from the lid body 14 is not excessively deep, and a blowhole is unlikely to be formed in the inner welded portion 41. To. And the inner side welding part 32 (the cover body side opposing surface 21a and the case side opposing surface 13e) which is a part of the matching part 40 is fuse | melted, and the inner side welding part 41 is formed.

  The outer welded portion 42 is formed by irradiating the laser beam L from the outside of the case 11 with the optical axis of the laser beam L along the outer mating portion 31. When forming the outer welded portion 42, the energy density of the laser beam L is set larger than the energy density when forming the inner welded portion 41 so that the penetration depth is deeper than that of the inner welded portion 41. The outer welded portion 42 is irradiated with the laser beam L so that the welding depth F2 is deeper than the inner welded portion 41 and the welding strength is increased. And the case main body 13 and the cover body 14 are joined by the inner side welding part 41 and the outer side welding part 42 being formed, and the case 11 is formed.

Next, the operation of the case 11 will be described.
As shown in FIG. 3B, the mating portion 40 of the case 11 is joined by an inner welded portion 41 and an outer welded portion 42. For this reason, when gas is generated in the case due to the reaction between the electrode assembly 12 and the electrolytic solution, the gas is first prevented from leaking from the inside of the case 11 by the sealing by the inner welded portion 41. The inner welded portion 41 is formed by suppressing the energy density of the irradiated laser beam L and making the penetration depth (welding depth F1) shallow so that a blow hole is hardly formed. Therefore, the inner welded portion 41 can ensure airtightness. Even if gas passes through the inner welded portion 41, the seal by the outer welded portion 42 prevents leakage from the inside of the case 11 through the mating portion 40. Therefore, the airtightness of the case 11 is enhanced by the two-stage structure of the inner welded portion 41 and the outer welded portion 42.

  The case 11 includes two welded portions, an inner welded portion 41 and an outer welded portion 42. In order to make it difficult for the inner welded portion 41 to form a blow hole, the joint strength of the entire case 11 is increased by the cooperation of the inner welded portion 41 and the outer welded portion 42 even if the joint strength is smaller than that of the outer welded portion 42. Can be increased.

According to the above embodiment, the following effects can be obtained.
(1) The joining portion 40 of the case main body 13 and the lid body 14 is joined by the inner welding portion 41 and the outer welding portion 42. For this reason, the airtightness and pressure-resistant strength of case 11 can be improved by the welding part provided in two different positions. Laser welding is performed so that blow holes are not easily formed at the inner welded portion 41, and laser welding is performed at the outer welded portion 42 so as to ensure the bonding strength. Therefore, unlike the case where the output peak value of the laser beam is adjusted in two stages at one welded portion, the airtightness and the pressure resistance can be easily increased.

  (2) The energy density input when forming the inner welded portion 41 is made smaller than the energy density input when forming the outer welded portion 42. And the welding depth F1 of the inner side welding part 41 was made shallower than the welding depth F2 of the outer side welding part 42. FIG. For this reason, in the inner side welding part 41, it is prevented that the matching part 40 melt | dissolves excessively, and it can make it difficult to form a blow hole in the inner side welding part 41. FIG. Moreover, in the outer side welding part 42, the mating part 40 can be firmly joined by the deep welding depth F2. Therefore, the airtightness can be reliably increased at the inner welded portion 41, and the pressure resistance can be reliably increased at the outer welded portion 42.

  (3) The inner welded portion 41 and the outer welded portion 42 are formed by irradiating the laser beam L from different positions of the case 11. For this reason, for example, the melted material does not fall into the case 11 by changing the output peak value of the laser beam L continuously and irradiating it to one place.

  (4) The lid 14 is provided with the flange portion 22, and the outer welded portion 42 is formed in a state where the supported surface 22 a of the flange portion 22 is supported by the support surface 13 c of the case body 13. The outer welded portion 42 has the optical axis (irradiation direction) of the laser light L along the outer mating portion 31 so that the depth direction of the outer welded portion 42 is formed along the outer mating portion 31. For this reason, the outer welded portion 42 can be formed extensively in a state where the supported surface 22a and the support surface 13c are in surface contact, and the case main body 13 and the lid body 14 can be reliably joined by the outer welded portion 42. it can.

  (5) The inner welded portion 41 and the outer welded portion 42 are formed by irradiating the laser beam L along the optical axis (irradiation direction) of the laser light L along the inner mating portion 32 and the outer mating portion 31. Yes. The inner mating portion 32 and the outer mating portion 31 are melted along the optical axis of the laser beam L, respectively, and the depth direction of the inner welding portion 41 and the outer welding portion 42 is changed to the inner mating portion 32 and the outer mating portion 31. Formed along. Therefore, for example, the inner welded portion 41 and the outer welded portion 42 are more reliably hermetically sealed and bonded than in the case where the inner welded portion 41 and the outer welded portion 42 extend in the direction intersecting with the extending direction of the mating portion 40. Can be increased.

In addition, you may change the said embodiment as follows.
As shown in FIG. 4A, an annular rib 13g surrounding the lid body 14 may be erected around the support surface 13c of the peripheral wall 13b. Further, the lid 14 may have a configuration in which the insertion portion 21 is deleted. The inner surface 14d of the lid 14 is supported by the support surface 13c, and is disposed inside the annular rib 13g. The inner peripheral surface 13h of the support surface 13c and the annular rib 13g is a case-side mating surface 13f. In the lid body 14, the inner surface 14d and outer peripheral surface 14g thereof are the lid-body-side mating surface 14f, and the case-side mating surface 13f. And a lid-side mating surface 14f, a mating portion 50 is formed.

  The outer peripheral surface 14g of the lid 14 and the inner peripheral surface 13h of the annular rib 13g are abutted against each other to form an outer mating portion 53. The inner surface 14d of the lid 14 and the support surface 13c of the case main body 13 Are abutted against each other to form an inner mating portion 54. A mating portion 50 is formed from the outer mating portion 53 and the inner mating portion 54.

  As shown in FIG. 4B, the inner welded portion 51 is formed by irradiating the laser light L from the outside of the case 11 with the optical axis (irradiation direction) of the laser light L along the inner matching portion 54. Is done. The outer welded portion 52 is formed by irradiating the laser beam L from the outside of the case 11 with the optical axis (irradiation direction) of the laser beam L along the outer mating portion 53. And the welding depth F1 of the inner side welding part 51 is shallower than the welding depth F2 of the outer side welding part 52. FIG. In addition, the welding depth of the inner side welding part 51 and the outer side welding part 52 may be reversed.

  Further, in the case 11 shown in FIG. 4, as shown by a two-dot chain line in FIG. 4A, the alignment from the outer surface 14 c of the lid body 14 to the support surface 13 c of the case body 13 and the inner surface 14 d of the lid body 14. The inner welded part 51 may be formed by irradiating the laser beam L toward the part 50. Further, the inner welded portion 51 may be formed by friction stir welding (welding), and the outer welded portion 52 may be formed by laser welding.

  In addition, in the lid body 14 and the case main body 13 shown in FIG. 4, as shown in FIG. 6, the inner welded portion 61 may be formed by laser welding and the outer welded portion 62 may be formed by friction stir welding (welding). Good. In the friction stir welding, the rotating member T is rotated by a rotating mechanism (not shown), and the rotating rotating member T is brought into contact with the outer surface 14c of the lid 14 and the tip surface of the annular rib 13g to generate frictional heat therebetween. Let Then, the lid 14 and the annular rib 13g are softened and joined by frictional heat.

  In this case, since the outer welded portion 62 is joined by friction stir welding, even if frictional heat is generated, it is difficult to reach a high temperature, and the weld depth is shallow, so that no blowhole is formed in the outer welded portion 62. . In addition, the pressure depth can be ensured by increasing the welding depth F1 of the inner welded portion 61.

As shown in FIGS. 5A and 5B, an inner welded portion 41 and an outer welded portion 42 may be formed in the inner mating portion 32.
The relationship between the welding depths of the inner welded portion 41 and the outer welded portion 42 may be reversed from that of the embodiment, and the weld depth F1 of the inner welded portion 41 may be made deeper than the weld depth F2 of the outer welded portion 42. .

  In the form shown in FIG. 5B, the outer welded portion 42 may be formed by irradiating the outer mating portion 31 with the laser beam L from the outer peripheral surface 13d of the peripheral wall 13b. In this case, the inner welded portion 41 is formed in a state where the optical axis (irradiation direction) of the laser light L does not follow the mating portion 40.

In the embodiment, the inner welded portion 41 may be formed by laser welding, and the outer welded portion 42 may be formed by friction stir welding.
O Although embodied in the case 11 of the secondary battery 10 as a sealed container, it may be embodied in a sealed container other than the secondary battery 10.

The case 11 may be formed in a columnar shape or an elliptical columnar shape.
O You may actualize as a nickel-hydrogen secondary battery as an electrical storage apparatus, or an electric double layer capacitor.

  L ... Laser beam, S ... Opening, F1, F2 ... Welding depth, 11 ... Case as a sealed container, 13 ... Case body, 13f ... Case side mating surface, 14 ... Cover body, 14f ... Cover body side mating surface, 31, 53 ... Outer mating part, 32, 54 ... Inner mating part, 40, 50 ... Matching part, 41, 51, 61 ... Inner welding part, 42, 52, 62 ... Outer welding part.

Claims (10)

The opening of the metal case body is closed with a metal lid, the case side mating surface to the lid in the case body, and the lid side facing the case side mating surface in the lid A sealed container in which an annular mating portion with a mating surface is welded to join the case body and the lid,
By welding from the outside of the sealed container, there are two annular welded parts, an outer welded part and an inner welded part. In the mating part, the inner welded part is more sealed than the outer welded part. An airtight container characterized by being located inside.   The sealed container according to claim 1, wherein a weld depth from an outer surface of the sealed container is shallower in the inner welded part than in the outer welded part.   The said inner weld part and the said outer weld part are formed by laser welding, The depth direction of at least one of the said inner weld part and the said outer weld part is formed along the said joining part. Item 3. The sealed container according to Item 2.   The sealed container according to claim 3, wherein a depth direction of the outer welded portion is formed along the mating portion.   The mating portion includes an inner mating portion positioned inside the sealed container, and an outer mating portion bent with the inner mating portion and positioned outside the sealed container, and the depth direction of the inner welded portion The sealed container according to claim 3, wherein a depth direction of the outer welded portion is formed along the inner mating portion and the outer mating portion, respectively. A manufacturing method of a sealed container for joining a mating portion of a metal case body having an opening and a metal lid that closes the opening,
Irradiating a laser beam from the outside of the sealed container to form two annular welds on the mating part,
The two annular welded portions are an outer welded portion and an inner welded portion located inside the sealed container with respect to the outer welded portion,
The manufacturing method of the airtight container characterized by making the energy density of the said laser beam at the time of forming the said inner side weld part smaller than the energy density of the said laser beam at the time of forming the said outer side weld part. A manufacturing method of a sealed container for joining a mating portion of a metal case body having an opening and a metal lid that closes the opening,
Forming two annular welds on the mating portion from the outside of the sealed container,
The welded portion is an outer welded portion and an inner welded portion located inside the sealed container with respect to the outer welded portion,
A method for manufacturing an airtight container, wherein the inner welded portion is formed on the mating portion by laser welding, and the outer welded portion is formed by friction stir welding.   The manufacturing method of the airtight container of Claim 6 which laser-welds at least one of the said inner side welding part and the said outer side welding part along the said matching part with the said laser beam.   The manufacturing method of the airtight container of Claim 6 which laser-welds the said outer side welding part along the said matching part with the said laser beam.   The mating portion includes an inner mating portion positioned inside the sealed container, and an outer mating portion bent with the inner mating portion and positioned outside the sealed container, and forms the inner welded portion. The manufacturing method of the airtight container of Claim 6 which laser welds the said laser beam and the said laser beam which forms the said outer side welding part along the said inner side joining part and the said outer side joining part, respectively.