JPH11250871A - Manufacture of sealed battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method for a sealed battery capable of further improving efficiency of laser welding by restricting generation of cracking to the utmost while restricting laser beam radiation energy low at the time of laser welding. SOLUTION: In processes of manufacturing an outer can 10 and a sealing plate 31, an inner angular part of an opening edge part 11 of the outer can and an angular part of an outer circumferential part of the sealing plate 31 are diagonally cut, so a V-groove 41 is formed when the sealing plate 31 is engaged in the opening part 11 of the outer can 10. For sealing it, the laser beam 50 is concentrated to the boundary 40 for radiation while scanning. The groove 41 closes the laser beam 50 projected along the boundary 40 to improve an absorption ratio of it.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a sealed battery having a step of sealing a battery outer can and a sealing plate by laser welding.

[0002]

2. Description of the Related Art In recent years, with the demand for portable equipment such as portable telephones, AV equipment, and computers, demands for higher performance of batteries have been rapidly increasing. Among them, nickel cadmium batteries, nickel hydrogen batteries, There is a high demand for a secondary battery such as a lithium ion secondary battery.

[0003] Such a battery is generally a sealed type, and the shape of the battery is generally cylindrical or rectangular. In particular, prismatic sealed batteries are attracting attention because of their excellent space efficiency when mounted on portable equipment. Such a sealed battery is manufactured by deep-drawing a metal plate, forming a bottomed cylindrical shape to produce an outer can, and housing a power generating element including a positive electrode and a negative electrode in the outer can, It is manufactured by attaching a sealing plate to the opening of the outer can and sealing it.

[0004] Nickel-plated steel plates and stainless steel plates have been used in many cases as metal plates, but in order to reduce the weight of batteries, aluminum alloys containing manganese or the like added to aluminum are now used. Boards have also been used in many cases. The sealing process is necessary to prevent leakage of the electrolyte or gas when the inside of the battery becomes high pressure, but the degree of reliability greatly affects the reliability and life of the battery.

[0005] This sealing process is often performed by a mechanical caulking method, but when sealing by the caulking method is difficult (particularly in the case of a rectangular sealed battery), a sealing method by laser welding is also performed. ing. In this laser welding method, welding is performed by scanning while irradiating a laser beam along a boundary between the outer peripheral portion of the sealing plate and the opening edge of the outer can.

[0006]

In such laser welding, it is desired from the viewpoint of production efficiency that the energy of the laser beam applied to the welding location be kept as low as possible. That is, in an actual sealing device, a laser beam from one laser light source is equally divided and branched by a plurality of optical fibers so that a plurality of batteries can be sealed in parallel so that a plurality of batteries can be irradiated. The position is illuminated. In this case, if the energy irradiated to each irradiation position can be kept low, even if the output of the laser light source is the same, more batteries can be sealed in parallel, which is efficient.

However, when the irradiation energy of the laser beam is suppressed to a low level, there is a problem that cracks are easily generated along the welding line on which the spot of the laser beam is scanned. This is because of the mechanism of crack generation, the part that has been melted by irradiating laser light (molten pool).
However, it is thought that cracks occur due to thermal stress generated in the vicinity during cooling, but if the irradiation energy of laser light is low, the molten pool can be cooled rapidly and large thermal stress occurs. Probable cause.

[0008] In particular, when an aluminum alloy plate is used for the outer can and the sealing plate, cracks are likely to occur in the welded portion. This is because aluminum alloy has a lower tensile strength than iron or stainless steel, and the welded portion is rapidly cooled due to its high thermal conductivity. In order to solve such a problem, there is a method of applying black coating to a portion to be irradiated with laser light, which is effective in improving the absorptance of laser light. In this case, the black pigment to be applied is molten pool. Therefore, there is a problem that the strength of the welded portion is reduced.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has been made in consideration of the following problems.
It is an object of the present invention to provide a manufacturing method capable of suppressing the generation of cracks as much as possible and keeping the irradiation energy of laser light low, thereby improving the efficiency of laser welding as compared with the conventional method.

[0010]

In order to achieve the above object, in the method of manufacturing a sealed battery according to the present invention, a step of producing a bottomed cylindrical outer can and a sealing plate for closing an opening of the outer can is provided. In the state where the sealing plate is attached to the opening of the outer can, a groove is formed along the boundary between the outer peripheral portion of the sealing plate and the opening edge of the outer can, so that the outer periphery of the sealing plate and the opening of the outer can are formed. A sub-step of molding at least one with the edge is provided.

According to the above manufacturing method, when the sealing plate is attached to the opening of the outer can at the time of sealing, a groove is formed along the boundary between the outer peripheral portion of the sealing plate and the opening edge of the outer can. In the closing step, when the laser light is irradiated along the groove, a part of the reflected light of the laser light irradiated into the groove is again irradiated into the groove (the operation of confining the laser light into the groove). Thereby, the absorptance of the laser light is improved.

[0012] Then, as the absorptance of the laser light is improved,
Even if the irradiation energy of the laser light is reduced, the absorption energy can be maintained. That is, the irradiation energy of the laser beam can be made smaller than before, while suppressing the occurrence of cracks. In the above sub-step, if the inclined surface inclined with respect to the optical axis of the laser light irradiated in the sealing step is formed as a wall surface of the groove, the action of confining the laser light in the groove in the sealing step becomes greater. In addition, the absorptance of laser light can be further improved.

Here, if one wall surface of the groove is formed on the outer peripheral portion of the sealing plate and the other wall surface of the groove is formed on the opening edge of the outer can,
Furthermore, when the opening width of the groove is W and the depth is D, ta
If n30 ° ≦ 2D / W ≦ tan70 ° is satisfied, the effect of improving the absorptivity becomes large. In particular, when the sectional shape of the groove is V-shaped or U-shaped, the effect is good and the groove can be easily formed.

Further, in the case of a sealed battery in which the outer can and the sealing plate are made of an aluminum alloy, cracks are easily generated at the time of welding, so that a great effect can be obtained by applying the manufacturing method of the present invention.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Structure of Battery] FIG. 1 is a perspective view of a sealed rectangular battery according to an embodiment of the present invention. This prismatic sealed battery is a lithium ion secondary battery,
An electrode group 20 in which a negative electrode plate 21 and a positive electrode plate 22 are laminated via a separator 23 and a non-aqueous electrolyte are accommodated inside a bottomed rectangular cylindrical outer can 10. The structure is sealed with a sealing body 30.

The outer can 10 is formed by forming a plate of an Al-Mn-based alloy into a square cylinder with a bottom. This Al-Mn-based alloy is lightweight because it contains aluminum as a main component, and has a higher tensile strength than aluminum alone due to the addition of manganese. The content of manganese is suitably about 1.0 to 1.5 wt%, and when the content of manganese is too large, workability and weldability at the time of molding an outer can decrease.

As shown in FIG. 1, the sealing body 30 has a nail-shaped negative electrode terminal 32 at the center of a sealing plate 31 formed so as to fit into the opening of the outer can 10 via an insulating packing 33. It is a configuration that penetrates and attaches. Sealing plate 31
Is a plate of the same Al-Mn alloy as the outer can 10 punched out in the same rectangular shape as the opening of the outer can 10.

The thickness of the outer can 10 and the sealing plate 31 is set as thin as possible within a range where required strength can be maintained, and usually set to about 500 μm. A current collector 34 is mounted below the negative terminal 32 (inside the battery), and a washer 35 is mounted above the negative terminal 32 (outside the battery). The negative electrode terminal 32, the current collector 34, and the washer 35 are fixed to the sealing plate 31 by crimping while being insulated from the sealing plate 31 by the insulating packing 33.

The negative electrode plate 21 of the electrode group 20 is formed by coating layered carbon (graphite powder) on a plate-shaped core, and is surrounded by a separator 23. The core of the negative electrode plate 21 and the current collecting plate 34 are connected by a lead plate 25. On the other hand, the positive electrode plate 2 of the electrode group 20
Reference numeral 2 is a plate-like core coated with a positive electrode mixture comprising a lithium-containing oxide (eg, lithium cobalt oxide) as a positive electrode active material and a conductive agent (eg, acetylene black). It is in direct contact with and electrically connected to the dual-purpose exterior can 10.

The non-aqueous electrolyte is obtained, for example, by dissolving LiPF6 as a solute in a mixed solvent consisting of ethylene carbonate and dimethyl carbonate. Sealing plate 3
The outer peripheral portion of the housing 1 and the open end of the outer can 10 are sealed by laser welding. Although not shown in FIG. 1, an insulating sleeve 26 made of an insulating resin is interposed between the electrode group 20 and the sealing plate 31 (see FIGS. 2 and 3).
As a result, the electrode group 20 is fixed at a fixed position in the outer can 10, and is prevented from contacting with the sealing body 30.

[Method of Manufacturing Battery] Next, a method of manufacturing the rectangular sealed battery will be described. FIG.
FIG. 4 is an enlarged view of a main part in a state where the sealing plate 31 is inserted into the opening of the outer can 10 and the vicinity of the opening edge of the outer can 10. First, an outer can 10 is manufactured by molding a plate of an Al—Mn-based alloy into a square cylinder with a bottom. Also,
An Al-Mn-based alloy plate is punched to produce a sealing plate 31. Then, in this step, a notch 11a which is notched obliquely is formed at an inner corner of the opening edge 11 of the outer can 10,
A notch 31a that is cut obliquely is also formed at the corner of the outer peripheral portion of the sealing plate 31.

The notch 31a and the notch 11a are set in such a shape that a V-shaped groove 41 is formed in a state where the sealing plate 31 is fitted in the opening of the outer can 10 as shown in FIG. I do. The grooves 41 are formed to improve the absorption of the irradiated laser light in a later laser sealing step. Explaining the above steps more specifically, the outer can 10 is manufactured by forming a flat plate of an aluminum alloy by transfer drawing using a punch and an ironing die. Here, as described below, the notch 11a and the notch 31a are formed simultaneously with the molding of the outer can 10 and the sealing plate 31.

The basic method of molding the outer can 10 is the same as the conventional method of molding an outer can, except that the outer can 1
Since the shape on the inner surface side of 0 follows the shape of the punch used,
The notch 11a is formed in the opening edge 11 of the outer can 10 by using a punch having a shape in which a portion corresponding to the notch 11a is expanded. On the other hand, the sealing plate 31 is manufactured by punching a flat plate of an aluminum alloy with a punch. Also here, the shape of the outer peripheral portion of the sealing plate to be manufactured follows the shape of the punch to be used. Therefore, the notch 31a is formed in the outer peripheral portion of the sealing plate 31 by using a punch having a shape corresponding to the notch 31a. To form

According to this method, a groove having a desired shape can be easily formed, and it is not necessary to provide a step for forming a notch separately from the molding of the outer can and the sealing plate. Good. Next, an insulating packing 33, a negative electrode terminal 32, and a current collector plate 34 are combined and loaded into the sealing plate 31, and a washer 35 is fitted on the upper portion of the negative electrode terminal 32 and crimped to form the sealing body 30.

The negative electrode plate 21 with the lead plate 25 is covered with the separator 23, and the positive electrode plate 22 and the negative electrode plate 21 are alternately laminated to form the electrode group 20. The electrode group 20 manufactured in this manner is inserted into the outer can 10, and the lead plate 25 is passed through the insulating sleeve 26 so that the current collecting plate 3
4 and electrically connected. Then, a non-aqueous electrolyte is injected into the outer can 10 to impregnate the electrode group 20.

Next, the insulating sleeve 26 is mounted on the upper part of the outer can 10, and the sealing body 30 is mounted on the opening of the outer can 10, and the outer peripheral part of the sealing body 30 and the outer Welding is performed by scanning the opening edge portion 10 with the laser beam along the boundary 40 between the two. [Sealing by Laser Welding] FIG. 3 is a view showing a state in which the outer can is sealed by laser welding.

In the apparatus shown in FIG.
Can be driven in any direction within a plane parallel to the sealing plate 31. Then, the laser light 50 is guided to the condenser lens 51 from a laser light oscillation device (not shown) via an optical fiber. The laser light oscillation device emits light using yttrium aluminum garnet (YAG), and the laser light 50 is output in a pulse form (for example, the laser pulse repetition rate: 50p).
ps). Then, this laser beam 50 is
To form a small circular spot 52 (spot diameter: several hundred μm) on the boundary 40 between the sealing plate 31 and the opening edge 11, that is, on the groove 41.

By means of such a laser beam irradiation method, a member (such as an insulating sleeve 26) around a portion to be welded.
The spot 52 can be locally melted without thermally damaging the portion. In the portion of the spot 52 irradiated with the laser beam 50, the sealing plate 31 and the outer can 1
The zero-opening edge 11 melts to form a weld pool, which solidifies in a short time. In FIG. 3, reference numeral 60 denotes a welded portion where the molten pool has solidified.

In addition, an inert gas (nitrogen gas) is injected around the spot 52 of the laser beam 50, thereby preventing the welded portion from being oxidized. The repetition rate of the laser light and the scanning speed of the condenser lens 51 in the laser light oscillation device are set such that the spot 52 of the laser light 50 appropriately overlaps the spot 52a irradiated immediately before (normally 40 to 60). %).

As described above, while the laser beam 50 is condensed on the boundary 40 by the condensing lens 51 and irradiated, the condensing lens 51 is scanned in the direction along the boundary 40 (the direction of arrow A in FIG. 3). By doing so, the welded portion 60 is formed continuously along the boundary 40. Then, welding is performed over the entire periphery of the boundary 40 to complete the sealing. [Explanation of Shape of Groove 41 and Effect on Laser Welding] The groove 41 has a function of confining the laser beam 50 irradiated along the boundary 40 and improving its absorptance. For this purpose, how the shape of the groove 41 is preferably set will be discussed below.

In order to improve the absorptance, the rate at which the laser light applied to the groove 41 is taken into the groove 41 as much as possible and the taken-in laser light is reflected and goes out of the groove 41 again Should be as small as possible. In order to capture a large amount of laser light into the groove 41, the end of the boundary 40 is preferably located at the bottom of the groove 41, and the width of the groove 41 is equal to or smaller than the diameter of the irradiation spot of the laser light. It is preferable to set it slightly larger.

Next, in order to reduce the rate at which the captured laser light is reflected and goes out of the groove, an inclined surface inclined with respect to the optical axis of the irradiated laser light is provided on the inner surface of the groove 41. Preferably, it is formed. This is because, by forming the inclined surface, the laser light irradiated to the inclined surface is multiple-reflected in the groove, and the absorption increases accordingly. In addition, such an inclined surface is preferably formed on both the outer peripheral portion of the sealing plate and the opening edge of the outer can.

In view of the above, it is desirable that the cross-sectional shape of the groove 41 be V-shaped or U-shaped. Also,
In the case of V-shape or U-shape, notch 11a and notch 3
Forming 1a is also relatively easy. Furthermore, when the opening width of the groove 41 is W and the depth is D, it is preferable that D / W is large to some extent, and tan30 ° ≦ 2D / W is satisfied (when the groove 41 is V-shaped, Sealing plate 31
The inclination angle θ with respect to the surface is preferably 30 ° or more).

However, if the depth W is set too large, it is necessary to increase the thickness of the sealing plate 31, which is not preferable in terms of cost. Therefore, tan30 ° ≦ 2D / W ≦
Set in the range of tan 70 ° (when the groove 41 is V-shaped,
The inclination angle θ is set in the range of 30 ° to 70 °), and it is particularly preferable to set 2D / W = tan45 °.

This will be described in more detail with reference to FIG. FIG.
Is a view showing grooves 41 of various shapes and a state of a laser beam irradiated on the grooves 41. The laser beams L1 to L4 are
The specular reflection is shown on the inner surface of FIG. FIG. 4 (a)
In the case of the V-shape (the inclination angle θ is about 45 °), the irradiated laser beams L1 to L4 are reflected twice on the inner surface of the groove. Further, in the U-shape as shown in (b), among the irradiated laser beams, L1 and L4 are reflected three times on the inner surface of the groove,
L2 and L4 are reflected once on the inner surface of the groove.

In both cases (a) and (b), the average number of reflections of the entire laser light is much larger than 1, so that the absorptance is considerably improved. On the other hand, as shown in FIG. 4C, when the D / W is small even in the U-shape, the number of reflections of each of the laser beams L1 to L4 is 1, and the absorptance does not improve much. In addition, as shown in FIG. 4D, when the surface inclined with respect to the optical axis of the laser beam is not in the groove 41,
The number of reflections of each of the laser beams L1 to L4 is 1, and the laser beam absorptivity does not improve much.

However, when the laser beam is actually reflected, it is partially irregularly reflected (usually about 5 to 7% is irregularly reflected), and therefore, as shown in FIGS. Even in this case, a part of the light beam irregularly reflected is again applied to the inner surface of the groove 41. Accordingly, even in the case shown in FIGS. 4C and 4D, a slight improvement in the laser light absorptivity is produced. FIG.
As shown in (e), when a notch is not formed in the sealing plate 31 and a notch is formed only on the opening edge 11 side of the outer can 10, the laser beams L1 and L2 applied to the sealing plate 31 side. Does not have the effect of improving the absorptance, but the laser beams L1 and L2 applied to the outer can 10 have the effect of improving the absorptivity, so that some effect is produced.

[0038]

EXAMPLES (Examples) A rectangular sealed battery for a cellular phone was manufactured based on the above embodiment. The thickness of the outer can 10 and the sealing plate 31 was 500 μm. The groove 41 was V-shaped, the inclination angle θ was 45 °, and the opening width was 500 μm.

At the time of welding, the wavelength of the YAG laser beam is
1.064 μm, the diameter of the irradiation spot is about 500 μm
The irradiation power is 1.52, 1.14, 0.86 (×
10 ⁶W / cm^Two) In three stages. (Comparative example) Same as the above embodiment except that the groove 41 was not formed.
A rectangular sealed battery was manufactured in the same manner.

(Experiment 1) Batteries were manufactured according to the manufacturing methods of Examples and Comparative Examples, and the yield (the ratio at which no crack occurred) was examined. The results are as shown in Table 1.

[0041]

[Table 1]

As is clear from Table 1, when the irradiation power of the laser beam is relatively high at 1.52 (× 10 ⁶ W / cm ² ), the yield is good in both the embodiment and the comparative example. When the power becomes as low as 1.14 (× 10 ⁶ W / cm ² ), the yield is good in the example, but the yield is considerably lowered in the comparative example. Irradiation power is 0.86 (× 10
⁶ W / cm ² ), the yield is 9 in the embodiment.
Although it was kept at 0%, cracks occurred in all of the comparative examples.

(Experiment 2) FIG. 5 is a diagram showing the state of an experiment for examining the relationship between the groove shape and the reflectivity of laser light. The same aluminum alloy plate 70 as the outer can of the embodiment was used.
A groove 71 having a U-shape is formed, and the opening width of the groove 71 is 500 μm.
m, and the inclination angle θ of the inner surface of the groove 71 with respect to the surface of the aluminum alloy plate 70 was set to three values of 30 °, 45 °, and 70 °.

Then, the aluminum alloy plate 70 having the grooves 71 of the respective inclination angles and the aluminum alloy plate 70 having no grooves are formed.
(Inclination angle θ = 0 °) was irradiated with a YAG laser beam, and the reflectance was measured using an integrating sphere. Here, the laser beam to be irradiated was fixed at a spot diameter of about 500 μm, and the measurement was performed while continuously changing the wavelength. In the method for measuring the reflectance using an integrating sphere, as shown in FIG. 5, an integrating sphere 80 is placed on a groove 71, and a laser beam 72 is applied to the groove 71 from above the integrating sphere 80.

The detector 81 is provided on the aluminum alloy plate 70.
Is installed in the direction in which the laser light 72 is regularly reflected by
The amount of reflected light 73 directly reflected upward from the groove 71 is measured. Further, the reflected light 74 reflected in all directions from the groove 71 is collected by an integrating sphere 80 on a detector 82,
Then, the total light quantity is measured as the total reflection light quantity.

FIG. 6 is a characteristic diagram showing the relationship between the wavelength of the YAG laser beam and the total reflectance as a result of the total reflection light amount measured by the detector 82. In FIG. 6, when the inclination angle θ is 0 ° at a wavelength of 1.064 μm of the laser beam, the total reflectance is about 80%. Wavelength 1.064μ
It can be seen that only about 20% of m) is absorbed.

On the other hand, when the inclination angle θ is in the range of 30 ° to 70 °, the total reflectance is reduced to about 60%. By forming such a V-shaped groove, laser light (wavelength 1.064 μm ) Is absorbed by about 40%. In addition, according to FIG. 6, when the tilt angle θ is in the range of about 0 ° to 45 °, the total reflectance increases as the tilt angle θ increases, but the total reflectance hardly changes in the range of 45 ° to 70 °. I understand.

The results confirm that the inclination angle θ of the inner surface of the V-shaped groove 41 is most preferably about 45 °. (Other Matters) In Experiment 2, the shape of the groove 71 was U-shaped as shown in FIG. 4B, and 2D / W = tan30
°, tan45 °, tan70 °,
Almost the same results as in FIG. 6 were obtained.

In the above-described embodiment, the notch portion is formed simultaneously with the drawing process of the outer can and the punching process of the sealing plate. However, the drawing process of the outer can and the punching process of the sealing plate are performed as in the conventional case. After that, the opening edge of the outer can and the outer periphery of the sealing plate may be cut to form a notch. Further, in the above embodiment, the case of the lithium ion secondary battery has been described as an example.
The present invention is also applicable to a secondary battery such as a nickel-hydrogen battery or a primary battery.

In the above-described embodiment, the case where an aluminum alloy is used as the material of the outer can or the sealing plate has been described. Therefore, the present invention can be applied to a case where an alloy or metal such as stainless steel is used. Further, in the above embodiment, the sealed rectangular battery is described, but the manufacturing method of the present invention can be widely applied to a battery having a cylindrical or other bottomed cylindrical outer can.

[0051]

As described above, in the method for manufacturing a sealed battery according to the present invention, in the step of producing a bottomed cylindrical outer can and a sealing plate for sealing the opening of the outer can, the step of manufacturing the outer can is performed. When a groove is formed along the boundary between the outer peripheral portion of the sealing plate and the opening edge of the outer can when the sealing plate is mounted on the opening, at least the outer peripheral portion of the sealing plate and the opening edge of the outer can can be formed. By providing the sub-step of molding one, the absorptance of laser light at the time of sealing by the laser welding method can be improved. In addition, according to this method, since no material such as paint is mixed in the welded portion,
Irradiation energy of laser light can be made smaller than before, while suppressing generation of cracks.

An inclined surface of about 45 ° is formed on both the outer peripheral portion of the sealing plate and the opening edge of the outer can, and the sectional shape of the groove is V
If the shape is a U-shape or a U-shape, the absorption rate of laser light, which was conventionally about 20%, can be improved to about 40%. Therefore, it is possible to greatly improve the production efficiency of the laser sealing in the sealed battery.

In the case of a sealed battery in which the outer can and the sealing plate are made of an aluminum alloy, a great effect can be obtained by applying the present invention.

[Brief description of the drawings]

FIG. 1 is a perspective view of a prismatic sealed battery according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a main part in a state where a sealing plate is inserted into an opening of an outer can.

FIG. 3 is a view showing a state in which an outer can is sealed by laser welding.

FIG. 4 is a diagram showing grooves of various shapes and a state of a laser beam applied to the grooves.

FIG. 5 is a diagram showing a state of an experiment for examining a relationship between a groove shape and a reflectance of a laser beam.

FIG. 6 is a characteristic diagram showing the results of Experiment 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Outer can 11 Opening edge 11a Notch 20 Electrode group 21 Negative electrode plate 22 Positive electrode 23 Separator 26 Insulation sleeve 30 Sealing body 31 Sealing plate 31a Notch 40 Groove 50 Laser light

Continued on the front page (72) Inventor Keisho Yamamoto 2-5-5 Keihanhondori, Moriguchi-shi, Osaka Sanyo Electric Co., Ltd.

Claims (6)

[Claims] 1. An outer can producing step of producing an outer can having a bottomed cylindrical shape and a sealing plate for closing an opening of the outer can, a housing step of storing a power generation element in the outer can, and the outer can Attaching the sealing plate to the opening of the, the outer peripheral portion of the sealing plate and the opening edge of the outer can, welding by scanning while irradiating laser light along the boundary between both,
In the method for producing a sealed battery comprising a sealing step of sealing, the step of preparing the outer can includes: a step of forming a boundary between an outer peripheral portion of the sealing plate and an opening edge of the outer can in a state where the sealing plate is attached to the opening of the outer can. A method of forming at least one of an outer peripheral portion of a sealing plate and an opening edge of an outer can so as to form a groove along the shape of a sealed battery. 2. The sealed battery according to claim 1, wherein in the sub-step, an inclined surface that is inclined with respect to an optical axis of the laser beam irradiated in the closing step is formed as a wall surface of the groove. Manufacturing method. 3. The sealing according to claim 2, wherein in the sub-step, one wall surface of the groove is formed on an outer peripheral portion of the sealing plate, and the other wall surface of the groove is formed on an opening edge of the outer can. Method of manufacturing a battery. 4. In the sub-step, when the opening width of the groove is W and the depth is D, the groove is formed so as to satisfy tan30 ° ≦ 2D / W ≦ tan70 °. Production method of sealed batteries. 5. The method for manufacturing a sealed battery according to claim 2, wherein in the sub-step, the cross section of the groove is formed to have a V-shape or a U-shape. 6. The outer can and the sealing plate are made of an aluminum alloy.
5. The method for producing a sealed battery according to any one of the above items 5.