Welding device and method of manufacturing power storage device

Abstract

A welding device and a method of manufacturing an electricity storage device. The welding device (1) includes a laser irradiation section (20) that causes a laser to travel along a boundary between a case main body (120) and a sealing plate (130), that is, a laser irradiation region (A); and an inert gas supply section (30) that supplies inert gas (G) toward the laser irradiation region (A). The inert gas supply section includes a chamber (32) having an internal space (32a); a supply pipe (34) that supplies the inert gas to the internal space; a slit-shaped nozzle (36) that communicates with the supply pipe via the internal space and extends along one side of the laser irradiation region (A); and a rectifying member (38) that is a porous body housed in the internal space in a manner that separates the supply pipe and the nozzle. Deviation in the flow rate of the inert gas (G) in the extending direction of the nozzle (36) can be eliminated, and the oxygen concentration around the laser irradiation region (A) can be appropriately reduced.

Description

Technical Field

[0001] The technologies disclosed here relate to methods for manufacturing welding equipment and energy storage devices. Background Technology

[0002] The casing of an energy storage device is manufactured by installing a sealing plate at the opening of the casing body and welding the casing body and the sealing plate together. For example, Japanese Patent Application Publication No. 2013-197034 discloses a laser welding apparatus for welding the casing and cover of a secondary battery. This laser welding apparatus includes a laser irradiation unit, an inert gas supply pipe for injecting inert gas, an inert gas outlet for discharging inert gas, and a vacuum pump connected to the inert gas outlet. Furthermore, the inert gas outlet is positioned on the opposite side of the part where the diffusion of undesirable byproducts is to be avoided. In this laser welding apparatus, undesirable byproducts such as sputtering and fumes generated during laser welding are discharged along with the flow of inert gas.

[0003] Furthermore, Japanese Patent Application Publication No. 2019-130556 describes a laser welding apparatus that includes an adsorption clamp attached to the side of a housing body. This adsorption clamp includes: a first adsorption port, opening along the side of the housing body at a position equal to or lower than the cover; a second adsorption port, disposed above the first adsorption port and opening to a position higher than the cover; a first connector, provided in a first adsorption path communicating with the first adsorption port; and a second connector, provided in a second adsorption path communicating with the second adsorption port. Moreover, the adsorption device of this laser welding apparatus is connected to the first connector and the second connector. According to this laser welding apparatus, sputtering materials and fumes can be efficiently discharged.

[0004] Patent Document 1: Japanese Application Publication No. 2013-197034

[0005] Patent Document 2: Japanese Application Publication No. 2019-130556

[0006] Furthermore, during the welding of the shell body and the sealing plate, since an inert gas (such as nitrogen) is sprayed into the laser irradiation area, it is preferable to reduce the oxygen concentration around that area. This allows for the formation of a high-quality weld that inhibits oxidation. However, in actual manufacturing environments, sometimes even with the spraying of inert gas, the oxygen concentration around the laser irradiation area is not sufficiently reduced, resulting in oxidation of the weld. Summary of the Invention

[0007] The welding apparatus disclosed herein is used for welding a generally rectangular shell body having an opening on at least one side to a generally rectangular sealing plate that blocks the opening. The welding apparatus includes: a laser irradiation unit that directs a laser beam along the boundary between the shell body and the sealing plate, i.e., the laser irradiation area; and an inert gas supply unit that supplies inert gas toward the laser irradiation area. The inert gas supply unit includes: a chamber having an internal space; a supply pipe that supplies inert gas to the internal space of the chamber; a slit-shaped nozzle communicating with the supply pipe via the internal space and extending along at least one side of the laser irradiation area; and a rectifier, a porous body housed within the internal space in a manner that separates the supply pipe and the nozzle.

[0008] The inventors have discovered that in conventional welding apparatuses, turbulence can occur in the inert gas injected toward the laser irradiation area. In this case, the surrounding atmosphere is entrained by the inert gas, and therefore the oxygen concentration around the laser irradiation area may not be sufficiently reduced. In contrast, in the welding apparatus disclosed herein, the inert gas is injected from a slit-shaped nozzle extending along one side of the laser irradiation area. Furthermore, the inert gas supplied to the nozzle is passed through a flow-rectifying member that is a porous body. This allows for the injection of inert gas with a uniform flow velocity in the extension direction of the slit-shaped nozzle. As a result, atmospheric entrainment caused by turbulence is prevented. Therefore, according to the welding apparatus disclosed herein, the oxygen concentration around the laser irradiation area is sufficiently reduced, thus enabling the formation of a high-quality weld with suppressed oxidation. Attached Figure Description

[0009] Figure 1 This is a perspective view schematically showing an example of an energy storage device manufactured in the first embodiment.

[0010] Figure 2 This is a perspective view schematically representing the welding apparatus according to the first embodiment.

[0011] Figure 3 yes Figure 2 A top view of the welding apparatus shown.

[0012] Figure 4 yes Figure 3 A cross-sectional view in the direction of the arrow at line IV-IV.

[0013] Figure 5 This is a perspective view schematically illustrating the assembly process of the manufacturing method according to the first embodiment.

[0014] Figure 6 This is a schematic cross-sectional view of a welding apparatus according to another embodiment.

[0015] Figure 7This is a perspective view schematically illustrating an example of an energy storage device manufactured in another embodiment.

[0016] Figure 8 It is a coordinate graph showing the measurement results of oxygen concentration distribution in the test case.

[0017] Figure 9 This is a photograph of the appearance of the weld formed in Experiment Example 1.

[0018] Figure 10 This is a photograph of the appearance of the weld formed in Experiment Example 2.

[0019] Explanation of reference numerals in the attached figures

[0020] 1…Welding apparatus; 10…Positioning part; 12…First clamping member; 14…Second clamping member; 20…Laser irradiation part; 30…Inert gas supply part; 32…Cavity; 32a…Internal space; 32a1…First flow path; 32a2…Second flow path; 34…Supply pipe; 36…Nozzle; 38…Rectifying component; 38a…Mesh sheet; 38b…Perforated plate; 39…Gas supply source; 100…Electrical storage device; 110…Housing; 120…Housing body; 130…Sealing plate; A…Laser irradiation area; A1…First area; A2…Second area. Detailed Implementation

[0021] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the accompanying drawings. Furthermore, matters necessary for implementing the technology disclosed herein (e.g., the internal structure of the energy storage device) other than those specifically mentioned in this specification can be understood as design considerations for those skilled in the art based on prior art. The technology disclosed herein can be implemented based on the content disclosed in this specification and common technical knowledge in the art.

[0022] <First Embodiment>

[0023] The first embodiment of the technology disclosed herein will now be described.

[0024] A. Energy storage devices

[0025] In this specification, the structure of the energy storage device manufactured in this embodiment will first be described. Figure 1 This is a perspective view schematically illustrating an example of the energy storage device manufactured in the first embodiment. Furthermore, in the figures referenced in this specification, reference numerals X, Y, and Z represent the width direction, depth direction, and height direction, respectively. Additionally, reference numerals F, Rr, U, D, L, and R represent front, back, top, bottom, left, and right, respectively. These directions are merely provided for ease of explanation and are not intended to limit the orientation of the energy storage device, welding apparatus, etc.

[0026] Furthermore, the term "energy storage device" in this specification broadly includes devices capable of reversibly charging and discharging (secondary batteries, capacitors, etc.). Examples of secondary batteries include lithium-ion secondary batteries, lithium polymer batteries, and nickel-metal hydride batteries. Examples of capacitors include double-layer capacitors and lithium-ion capacitors.

[0027] Figure 1 The energy storage device 100 shown includes an electrode housing 180 (see reference). Figure 5 The casing 110 is a flat, square (i.e., roughly rectangular) container. The structure and materials of the electrode body 180 vary depending on the type of energy storage device 100, and the technology disclosed herein is not limited; therefore, detailed descriptions are omitted. The casing 110 is formed of aluminum, aluminum alloy, stainless steel alloy, etc. Furthermore, the casing 110 includes a casing body 120 and a sealing plate 130.

[0028] Figure 1 The housing body 120 shown has an opening 128 on one side (here, the side above U) (see reference). Figure 5 The container is a generally rectangular box. Specifically, the main body 120 of the shell has a generally rectangular bottom wall 122 extending in the width direction X, a pair of first side walls 124 extending upward U from the long side 122a of the bottom wall 122, and a pair of second side walls 126 extending upward U from the short side 122b of the bottom wall 122. Moreover, the opening 128 of the main body 120 is a generally rectangular opening surrounded by the upper ends 124a of the first side walls 124 and the upper ends 126a of the second side walls 126 (see reference). Figure 5 ).

[0029] The sealing plate 130 is a generally rectangular component that blocks the opening 128 of the housing body 120. Specifically, the sealing plate 130 has a pair of long sides 132 extending in the width direction X and a pair of short sides 134 extending in the depth direction Y. Moreover, when the sealing plate 130 is installed in the opening 128 of the housing body 120, the long sides 132 of the sealing plate 130 are arranged along the upper end 124a of the first side wall 124 of the housing body 120. On the other hand, the short sides 134 of the sealing plate 130 are arranged along the upper end 126a of the second side wall 126 of the housing body 120.

[0030] Here, the boundary between the housing body 120 and the sealing plate 130 becomes the area irradiated by laser L during the welding process described later (laser irradiation area A). For example... Figure 1As shown, the laser irradiation area A in this embodiment has a first area A1 and a second area A2. The first area A1 is the boundary between the long side 132 of the sealing plate 130 and the upper end 124a of the first sidewall 124. This first area A1 is a pair of linear areas extending along the width direction X. On the other hand, the second area A2 is the boundary between the short side 134 of the sealing plate 130 and the upper end 126a of the second sidewall 126. This second area A2 is a pair of linear areas extending along the depth direction Y. Moreover, the two ends of the first area A1 in the width direction X are connected to the two ends of the second area A2 in the depth direction Y. Thus, a generally rectangular frame-shaped laser irradiation area A is formed at the boundary between the housing body 120 and the sealing plate 130. At this time, the first area A1, where the long sides of the housing body 120 and the sealing plate 130 face each other, is longer than the second area A2, where the short sides of the housing body 120 and the sealing plate 130 face each other.

[0031] in addition, Figure 1 The energy storage device 100 shown includes a positive terminal 140, a negative terminal 150, and a gas discharge valve 160. The positive terminal 140 and the negative terminal 150 are connected to the electrode body 180 (see reference 110) within the housing 110. Figure 5 The conductive components are connected. The gas discharge valve 160 is a thin-walled portion that ruptures preferentially when the internal pressure of the housing 110 increases. These components are not limited to the technology disclosed herein, and conventionally known configurations can be used without particular restriction, therefore detailed descriptions are omitted.

[0032] B. Welding equipment

[0033] Next, the welding apparatus 1 according to the first embodiment will be described. Figure 2 This is a perspective view schematically representing the welding apparatus according to the first embodiment. Figure 3 yes Figure 2 A top view of the welding apparatus shown. Figure 4 yes Figure 3 A cross-sectional view in the direction of the arrow at line IV-IV. Furthermore, in Figure 4 For ease of explanation, the contents of the housing 110 (electrode body 180, etc.) are omitted from the illustration.

[0034] like Figures 2-4 As shown, the welding apparatus 1 according to this embodiment includes a laser irradiation unit 20 and an inert gas supply unit 30. Furthermore, the welding apparatus 1 also includes a positioning unit 10. The configurations of each part will be described below.

[0035] 1. Positioning unit 10

[0036] The positioning part 10 is a component that fixes the housing body 120. For example... Figure 3As shown, the positioning part 10 includes a pair of first clamping members 12 facing each other, clamping the housing body 120 in the depth direction Y, and a pair of second clamping members 14 facing each other, clamping the housing body 120 in the width direction X. The first clamping members 12 have a first abutting surface 12a that abuts against a first sidewall 124 of the housing body 120. By clamping the housing body 120 with the pair of first clamping members 12, movement of the housing body 120 in the depth direction Y is restricted. On the other hand, the second clamping members 14 have a second abutting surface 14a that abuts against a second sidewall 126 of the housing body 120. By clamping the housing body 120 with the pair of second clamping members 14, movement of the housing body 120 in the width direction X is restricted. This prevents positional deviation during laser L irradiation.

[0037] 2. Laser irradiation section 20

[0038] The laser irradiation unit 20 is a device that causes the laser L to travel along the boundary between the housing body 120 and the sealing plate 130, i.e., the laser irradiation area A. For example... Figure 2 As shown, the laser irradiation unit 20 is positioned U above the positioning unit 10 and the inert gas supply unit 30. Although detailed illustrations are omitted, the laser irradiation unit 20 includes an oscillator that generates laser L, an irradiation port that irradiates laser L, and optical path components (mirror, optical fiber, etc.) that guide laser L from the oscillator to the irradiation port. Furthermore, the laser irradiation unit 20 irradiates laser L into the laser irradiation area A of the energy storage device 100. At this time, the laser irradiation unit 20 adjusts the orientation of the irradiation port so that laser L travels along the laser irradiation area A. This forms a welded section spanning the housing body 120 and the sealing plate 130.

[0039] 3. Inert gas supply unit 30

[0040] The inert gas supply unit 30 is a device that supplies inert gas G toward the laser irradiation area A. For example... Figures 2-4 As shown, the welding apparatus 1 according to this embodiment includes a pair of inert gas supply units 30A and 30B facing each other in the depth direction Y, sandwiching the energy storage device 100. These pair of inert gas supply units 30A and 30B spray inert gas G from their outer sides toward the inner side in the depth direction Y (see reference). Figure 4 This reduces the oxygen concentration around the laser-irradiated area A (the space U above the laser-irradiated area A).

[0041] Furthermore, in this embodiment, the inert gas supply unit 30 is mounted on the positioning unit 10. Although the detailed structure will be described later, a pair of inert gas supply units 30A and 30B are respectively mounted on the first clamping member 12 of the positioning unit 10. As a result, the injection position (nozzle 36) of the inert gas G can be fixed near the laser irradiation area A. Consequently, the oxygen concentration around the laser irradiation area A can be appropriately reduced. In addition, by integrating the inert gas supply unit 30 and the positioning unit 10, it is also possible to reduce the number of components and miniaturize the welding apparatus 1.

[0042] The detailed structure of the inert gas supply units 30A and 30B will be described below. Furthermore, as described above, the welding apparatus 1 according to this embodiment includes a pair of inert gas supply units 30A and 30B facing each other, sandwiching the energy storage device 100 in the depth direction Y. Figure 4 As shown, the pair of inert gas supply units 30A and 30B are configured with a symmetrical structure sandwiching the energy storage device 100. Therefore, in the following description, the structure of the inert gas supply unit 30A at the front F will be mainly described. The inert gas supply unit 30 according to this embodiment includes a chamber 32, a supply pipe 34, a nozzle 36, and a rectifier 38.

[0043] (1) Chamber 32

[0044] Chamber 32 is a frame having an internal space 32a. For example... Figure 4 As shown, chamber 32 is mounted on positioning part 10. Specifically, chamber 32 is mounted such that it covers the upper surface 12b and back surface 12c of the first clamping member 12. An internal space 32a, serving as a flow path for inert gas G, is provided inside chamber 32. Figure 4 As shown, the internal space 32a is an L-shaped space with a first flow path 32a1 and a second flow path 32a2. The first flow path 32a1 extends along the height direction Z. On the other hand, the second flow path 32a2 extends along the depth direction Y. Moreover, at the inert gas supply section 30A at the front F, the end of the first flow path 32a1 above the front F is connected to the end of the second flow path 32a2 at the front F.

[0045] In addition, such as Figure 3As shown by the dashed lines, the width dimension w3 of the internal space 32a (the first flow path 32a1 and the second flow path 32a2) is approximately the same as the width direction w2 of the nozzle 36, which will be described later. Specifically, when the width direction w2 of the nozzle 36 is set to 100%, the width dimension w3 of the internal space 32a is preferably 80% to 120%, more preferably 90% to 110%, and particularly preferably 95% to 105%. As a result, the inert gas G can be supplied uniformly throughout the width direction X of the nozzle 36, thus suppressing turbulence in the inert gas G ejected from the nozzle 36.

[0046] (2) Supply pipe 34

[0047] Supply pipe 34 is a pipe that supplies inert gas G to the internal space 32a of chamber 32. Figure 2 The supply pipe 34 shown connects chamber 32 to gas supply source 39. Specifically, one end 34a of the supply pipe 34 is connected to the lower end D of the first flow path 32a1 of chamber 32 (see reference). Figure 4 Additionally, the other end 34b of the supply pipe 34 is connected to the gas supply source 39 (see reference). Figure 2 Furthermore, in this embodiment, the supply pipe 34 branches into multiple branches before connecting to the chamber 32 (in...). Figure 2 The system consists of four pipes (4 in total). Furthermore, the ends 34a of the multiple supply pipes 34 branching off are spaced at predetermined intervals in the width direction X. This disperses the flow rate of the inert gas G supplied to the internal space 32a of the chamber 32 in the width direction X, thus suppressing deviations in the flow velocity along this direction. Additionally, valves V1 to V4 are installed on each of the multiple supply pipes 34. Each valve V1 to V4 is configured to be independently opened and closed via a control device (not shown). This allows for more precise adjustment of the inert gas G supply in the width direction X.

[0048] Furthermore, the inert gas G supplied from the gas supply source 39 is not particularly limited, and a wide range of conventionally known gases that can be used for the oxidation prevention of metals can be used. For example, nitrogen, argon, carbon dioxide, etc., can be cited as inert gas G. In addition, inert gas G can also be mixed with multiple gases.

[0049] (3) Nozzle 36

[0050] Nozzle 36 is an opening that communicates with supply pipe 34 via internal space 32a. For example... Figure 4As shown, in this embodiment, the nozzle 36 is formed at the end of the internal space 32a of the chamber 32 (the end of Rr behind the second flow path 32a2). Thus, the inert gas G supplied from the supply pipe 34 is ejected from the nozzle 36 through the internal space 32a of the chamber 32. Furthermore, the nozzle 36 is positioned adjacent to the upper end (sealing plate 130) of the housing body 120. Therefore, the inert gas G ejected from the nozzle 36 is appropriately supplied to the laser irradiation area A.

[0051] In addition, such as Figure 2 and Figure 3 As shown, in this embodiment, the nozzle 36 is a slit-shaped opening extending along one side of the laser irradiation area A. By injecting inert gas G into the laser irradiation area A from this wide nozzle 36, inert gas G can be uniformly supplied to the entire area in the extension direction of the laser irradiation area A. Specifically, in this embodiment, the nozzle 36 extends along the first region A1 of the laser irradiation area A. By injecting inert gas G from the nozzle 36 extending along the first region A1 of the relatively long laser irradiation area A, the oxygen concentration can be uniformly reduced throughout the entire area in the width direction X of the laser irradiation area A. However, if such a wide nozzle 36 is provided, it is easy for a deviation in the flow rate of inert gas G to occur in the extension direction (width direction X) of the nozzle 36. Although details will be described later, the welding apparatus 1 according to this embodiment is configured such that even when a wide nozzle 36 is provided, the deviation in the flow rate of inert gas G can be suppressed.

[0052] In addition, such as in Figure 3 As indicated by the dashed line, the width w2 of the nozzle 36 is preferably the same as or greater than the width w1 of one side of the opposing laser irradiation area A (here, the first area A). Specifically, when the width w1 of the first area A1 is set to 100%, the width w2 of the nozzle 36 is preferably 100% to 130%, more preferably 100% to 120%. For example, when the width w1 of the first area A1 is set to 100%, the width w2 of the nozzle 36 is particularly preferably 108% or greater. This allows for the supply of inert gas G throughout the long side direction of the laser irradiation area A, thus more appropriately reducing the oxygen concentration around the laser irradiation area A. However, if the width w2 of the nozzle 36 is too long, a deviation in the flow velocity in the width direction X is likely to occur. For example, when the width of the nozzle 36 is 100 mm or more (especially 120 mm or more), a deviation in the flow velocity in the width direction X is particularly likely to occur. However, the welding apparatus 1 according to this embodiment is configured such that even with such a wide nozzle 36, deviations in the flow rate of the inert gas G can be suppressed.

[0053] (4) Rectifier component 38

[0054] The rectifier 38 is a porous body housed in the internal space 32a, separating the supply pipe 34 from the nozzle 36. This rectifier 38 eliminates deviations in the velocity of the inert gas G in the width direction X, preventing turbulence in the inert gas G after injection. This will be explained in detail below.

[0055] First, such as Figure 4 As shown, the inert gas G supplied from the supply pipe 34 passes through the internal space 32a of the chamber 32 and is then ejected from the nozzle 36. At this time, within the internal space 32a of the chamber 32, the flow velocity of the inert gas G increases near the supply pipe 34 and decreases away from the supply pipe 34. As a result, for the inert gases G1 to G5 (refer to...) supplied from the internal space 32a to the nozzle 36... Figure 3 Regarding the inert gas G, the flow rate may deviate in the width direction X. If inert gas G is injected from nozzle 36 while this deviation in the width direction X is occurring, turbulence is generated in the space U above the laser irradiation area A. In this case, the surrounding atmosphere is entrained into the inert gas G, and therefore the oxygen concentration around the laser irradiation area A may not be sufficiently reduced. In contrast, in the internal space 32a of the welding apparatus 1 according to this embodiment, a flow rectifier 38 is housed to separate the supply pipe 34 from the nozzle 36. As a result, the inert gas G supplied to the nozzle 36 passes through the flow rectifier 38. This eliminates the deviation in the flow rate of the inert gas G in the extension direction (width direction X) of the nozzle 36, thus preventing turbulence of the inert gas G after injection. As a result, the oxygen concentration around the laser irradiation area A can be sufficiently reduced, thus enabling the formation of a high-quality weld that suppresses oxidation.

[0056] Furthermore, in this embodiment, the rectifying component 38 is a mesh sheet 38a. This mesh sheet 38a fills the entire area of ​​the internal space 32a in the width direction X. Therefore, the inert gas G supplied to the nozzle 36 passes through the rectifying component 38 at least once, thus appropriately preventing deviations in the flow rate of the inert gas G in the width direction X. Moreover, "filling the entire area of ​​the internal space 32a in the width direction X" means that, when the width dimension of the internal space 32a is set to 100%, the mesh sheet 38a is filled in a range of 90% to 100% (preferably 95% to 100%, more preferably 99% to 100%).

[0057] And, as Figure 4As shown, the rectifying member 38 in this embodiment is a wound body of the mesh sheet 38a. Therefore, the inert gas G before being supplied to the nozzle 36 passes through the rectifying member 38 multiple times, thus more effectively eliminating deviations in the flow rate of the inert gas G. Furthermore, the number of times the mesh sheet 38a is wound is only required to be 2 times or more (preferably 3 times or more, more preferably 4 times or more). As the number of times the mesh sheet 38a is wound increases, it becomes easier to eliminate deviations in the flow rate of the inert gas G. On the other hand, the upper limit of the number of times the mesh sheet 38a is not particularly limited; it can be 10 times or less, 8 times or less, or even 6 times or less.

[0058] C. Manufacturing methods for energy storage devices

[0059] Next, a method for manufacturing an energy storage device using the welding apparatus 1 configured as described above (hereinafter also referred to as the "manufacturing method") will be described. The manufacturing method according to this embodiment is a method for manufacturing an energy storage device 100, which includes a generally rectangular shell body 120 having an opening on one side and a generally rectangular sealing plate 130 that blocks the opening of the shell body 120. The manufacturing method includes an assembly step and a welding step.

[0060] 1. Assembly process

[0061] Figure 5 This is a perspective view schematically illustrating the assembly process of the manufacturing method according to the first embodiment. In this assembly process, a sealing plate 130 is installed in the opening 128 of the housing body 120. In this process, firstly, a sealing plate 130 having a positive terminal 140 and a negative terminal 150 is prepared. Then, the positive terminal 140 and the negative terminal 150 are connected to the electrode body 180. Thus, the sealing plate 130 and the electrode body 180 become one unit. In this state, the electrode body 180 is inserted into the housing body 120 from the opening 128. Furthermore, the sealing plate 130 and the electrode body 180 are further lowered. Thus, the sealing plate 130 is installed in the opening 128 of the housing body 120.

[0062] 2. Welding process

[0063] In the welding process, inert gas G is supplied towards the boundary between the housing body 120 and the sealing plate 130, i.e., the laser irradiation area A, while the laser L travels along the laser irradiation area A. In this process, firstly, the housing body 120 is positioned between the first clamping member 12 and the second clamping member 14 of the positioning unit 10. Furthermore, the housing body 120 is clamped by the first clamping member 12 and the second clamping member 14 respectively. This fixes the housing body 120. Next, inert gas G is injected from the nozzle 36 of the inert gas supply unit 30. This reduces the oxygen concentration around the laser irradiation area A. Then, the welding apparatus 1 irradiates the laser L from the laser irradiation unit 20 into the laser irradiation area A. This welds the housing body 120 and the sealing plate 130. Since the oxygen concentration around the laser irradiation area A is reduced at this time, oxidation of the welded part after laser irradiation can be prevented.

[0064] Here, in the welding process of this embodiment, inert gas G is supplied from a slit-shaped nozzle 36 extending along at least one side (first region A1) of the laser irradiation area A, and the inert gas G before being supplied to the nozzle 36 is passed through a flow straightening member 38, which is a porous body. As a result, inert gas G with eliminated flow velocity deviation can be sprayed throughout the entire region of the laser irradiation area A in the extension direction (width direction X), thus suppressing the increase in oxygen concentration caused by atmospheric entrainment.

[0065] Furthermore, in the welding process of this embodiment, it is preferable to control the oxygen concentration around the laser irradiation area A to be 1.5% or less. This more reliably prevents oxidation of the welded portion after laser irradiation. Moreover, the oxygen concentration around the laser irradiation area A can be controlled by adjusting the supply amount of inert gas G from the gas supply source 39. As described above, the welding apparatus 1 according to this embodiment, in particular, can eliminate deviations in the flow rate of inert gas G in the width direction X. Therefore, even if the supply amount of inert gas G from the gas supply source 39 is increased, atmospheric entrainment caused by turbulence can be prevented.

[0066] <Other Implementation Methods>

[0067] The first embodiment of the technology disclosed herein has been described above. However, the technology disclosed herein is not limited to the first embodiment described above, and various modifications can be made as appropriate. Other embodiments of the technology disclosed herein will be described below.

[0068] 1. Composition of rectifier components

[0069] As described above, in the welding apparatus 1 according to the first embodiment, a wound body of mesh sheet 38a is used as the rectifier 38. However, the rectifier is not limited to a wound body of mesh sheet, as long as it is a porous body that separates the supply pipe and the nozzle. For example, in Figure 6 In the welding apparatus 1A shown, a perforated plate 38b with a through hole 38b1 for the inert gas G to pass through is used as a flow rectifying component 38. This perforated plate 38b is arranged to traverse the flow path of the inert gas G from the supply pipe 34 to the nozzle 36. Specifically, it extends throughout the width direction of the internal space 32a of the chamber 32 (relative to...). Figure 6 A perforated plate 38b is disposed over the entire area (vertical to the paper surface). This allows the inert gas G, before being supplied to the nozzle 36, to pass through the perforated plate 38b. Even with this flow-rectifying component 38, deviations in the flow velocity of the inert gas G in the width direction X can be eliminated. Furthermore, the flow-rectifying component can also employ other configurations. For example, the flow-rectifying component can be a laminate of mesh sheets. This laminate of mesh sheets can be a laminate formed by folding a single mesh sheet, or a laminate formed by overlapping multiple mesh sheets. Additionally, the flow-rectifying component can also use materials such as sponge or porous ceramic materials.

[0070] 2. Composition of the inert gas supply unit

[0071] like Figures 2-4 As shown, in the welding apparatus 1 according to the first embodiment, a pair of inert gas supply units 30A and 30B are arranged such that the energy storage device 100 is sandwiched in the depth direction Y. However, the welding apparatus only needs to have at least one inert gas supply unit. For example, it may be possible to provide only one. Figure 2 The inert gas supply section 30A at the front F and the inert gas supply section 30B at the rear Rr shown are both examples of inert gas supply sections 30A and 30B. Furthermore, in the welding apparatus 1 according to the first embodiment, inert gas supply sections 30A and 30B are respectively installed on a pair of first clamping members 12. In addition, inert gas supply sections can also be installed on second clamping members 14. In this case, inert gas can be supplied from all around (in four directions) of the energy storage device 100. Preferably, as in the first embodiment, a pair of inert gas supply sections 30A and 30B are arranged in the depth direction Y. This allows for the arrangement of nozzles 36 extending along the first region A1 of the strip, thus more effectively preventing turbulence.

[0072] In addition, such as Figure 3As shown, in the welding apparatus 1 according to the first embodiment, multiple (4) supply pipes 34 are connected to the chamber 32 at predetermined intervals in the width direction X. However, the number of supply pipes connected to the chamber is not particularly limited. For example, the number of supply pipes may be 1 or more, preferably 2 or more, and more preferably 3 or more. As the number of supply pipes increases, deviations in the flow rate of the inert gas G in the width direction X can be suppressed. From the viewpoint of component cost and device control, the number of supply pipes is preferably 10 or less, more preferably 8 or less, and particularly preferably 6 or less.

[0073] 3. Manufacturing Object

[0074] like Figure 1 As shown, in the first embodiment, a storage device 100 is manufactured, which includes a housing body 120 having an opening 128 on its surface, and a sealing plate 130 that blocks the opening 128. However, the technology disclosed herein can be widely applied to the manufacture of storage devices having a housing body and a sealing plate, and is not limited to them. Figure 1 The manufacture of the energy storage device 100 shown. For example, Figure 7 The illustrated energy storage device 100A includes: a housing body 120A with a pair of openings 128A1 and 128A2 on both sides in the width direction X; and two sealing plates 130A1 and 130A2 to block the pair of openings 128A1 and 128A2. In this energy storage device 100A, the housing body 120A is welded to the sealing plates 130A1 and 130A2 on the right side R and left side L in the width direction X, respectively. The technology disclosed herein can also be used to manufacture the energy storage device 100A with this configuration.

[0075] [Experimental Example]

[0076] The following describes test examples related to the technology disclosed herein. However, this description of test examples does not limit the technology disclosed herein to the technology related to the following tests.

[0077] 1. Sample preparation

[0078] In this experiment, three types of welding apparatuses with different inert gas supply sections (Examples 1-3) were prepared. Inert gas was sprayed into the laser welding area while laser welding the sealing plate to the main body of the shell was performed. The detailed conditions are described below.

[0079] (1) Experimental Example 1

[0080] First, in this experiment, a shell body with an opening size of 120mm × 13mm was prepared, and a sealing plate (119mm × 12mm) was installed at this opening. Furthermore, the shell body was installed on... Figures 2-3 The welding apparatus 1 shown is configured as follows. Furthermore, an inert gas G is supplied to the chamber 32 from the gas supply source 39. In this experiment, nitrogen gas with a flow rate of 60 L / min is supplied to the chamber 32 as the inert gas G. In Experiment 1, a winding body (rectifier 38) in which a mesh sheet 38a with a mesh diameter of 0.13 mm is wound twice is housed in the internal space 32a of the chamber 32. Laser welding is performed while nitrogen gas is ejected through the rectifyifier 38 from a slit-shaped nozzle 36 extending along the first region A1. A fiber laser (output: 2 kW, travel speed: 200 mm / min) is used in this laser welding.

[0081] (2) Experimental Example 2

[0082] In Test Example 2, a welding apparatus was used that did not have an internal space for housing the rectifying components, but had an internal flow path with a width approximately equal to that of a slit-shaped nozzle. Furthermore, all other conditions were set to be the same as in Test Example 1.

[0083] (3) Experimental Example 3

[0084] In Test Example 3, except that the nozzle with a different opening shape was used, the welding of the housing body and the sealing plate was performed under the same conditions as in Test Example 1. Specifically, in Test Example 3, a nozzle with 22 circular openings of 1 mm in diameter was used. Furthermore, these circular openings were formed at equal intervals along the width direction X.

[0085] 2. Evaluation Test

[0086] (1) Determination of oxygen concentration

[0087] In this experiment, the oxygen concentration around the laser welding area was measured. Specifically, nitrogen gas was injected from the nozzle of the welding device, and adsorption was performed on the space above the laser welding area. An oxygen concentration meter (model: OX-400) manufactured by Yokogawa Electric Corporation was used to measure the oxygen concentration of the collected gas. The diameter of the tube used for gas sampling was 2.5 mm, and the adsorption flow rate was set to 200 mL / min. Furthermore, in this experiment, gas was sampled at 10 mm intervals along the width direction (X), and the oxygen concentration at each of the 13 measurement points was measured. The oxygen concentration at each measurement point is shown below. Figure 8 As shown in the figure. In addition, the average, maximum, and minimum oxygen concentrations, as well as the difference between the maximum and minimum values, are shown in Table 1.

[0088] (2) Evaluation of welding quality

[0089] In this experiment, the quality of the weld after laser irradiation was confirmed by visual observation. Specifically, if oxidation occurs during laser irradiation, a wrinkled weld is formed. A photograph of the weld in Example 1 is shown below. Figure 9 As shown, a photograph of the welded portion in Test Example 2 is as follows. Figure 10 As shown.

[0090] Table 1

[0091]

[0092] like Figure 8 As shown in Table 1, compared with Examples 2 and 3, Test Example 1 confirmed a significant reduction in the oxygen concentration around the laser-welded area. In particular, the deviation in oxygen concentration along the width direction in Test Example 1 became very small. Furthermore, as... Figures 9-10 As shown in Table 1, in Experimental Example 1, the formation of wrinkles caused by oxidation of the weld was significantly suppressed. Therefore, it can be seen that by injecting inert gas through the rectifier from a slit-shaped nozzle to prevent atmospheric entrainment, the oxygen concentration during welding can be significantly reduced. Furthermore, it can be seen that laser welding performed in such a low-oxygen environment can produce a high-quality weld with suppressed oxidation.

[0093] The above descriptions illustrate specific examples of the techniques disclosed herein. These are merely illustrative and do not limit the technical solutions. The techniques described in the technical solutions include various modifications and alterations to the specific examples described above. For example, the techniques disclosed herein include the methods described in the following items.

[0094] <Project 1>

[0095] A welding apparatus is used for welding a generally rectangular shell body having an opening on at least one side to a generally rectangular sealing plate that blocks the opening, wherein...

[0096] The above-mentioned welding device includes:

[0097] The laser irradiation section causes the laser to travel along the boundary between the main body of the housing and the sealing plate, i.e., the laser irradiation area; and

[0098] The inert gas supply unit supplies inert gas toward the laser irradiation area.

[0099] The aforementioned inert gas supply unit is equipped with:

[0100] A chamber, having an internal space;

[0101] A supply pipe supplies the inert gas into the internal space of the aforementioned chamber;

[0102] A slit-shaped nozzle communicates with the supply tube via the aforementioned internal space and extends along at least one side of the laser irradiation area; and

[0103] The rectifier is a porous body housed in the internal space in a manner that separates the supply pipe from the nozzle.

[0104] <Project 2>

[0105] According to the welding apparatus described in Project 1, among which,

[0106] The aforementioned rectifier component is a mesh sheet.

[0107] <Project 3>

[0108] According to the welding apparatus described in Project 2, among which,

[0109] The aforementioned rectifier is a wound or laminated body of the aforementioned mesh sheet.

[0110] <Project 4>

[0111] According to the welding apparatus described in Project 1, among which,

[0112] The aforementioned rectifier is a perforated plate with through holes for the passage of the aforementioned inert gas.

[0113] <Project 5>

[0114] According to the welding apparatus described in any one of items 1 to 4, among which,

[0115] The laser irradiation area has a first region extending along the long side of the main body of the housing.

[0116] The nozzles mentioned above extend along the first region.

[0117] <Project 6>

[0118] According to the welding apparatus described in any one of items 1 to 5, among which,

[0119] The welding device described above also includes a positioning part for fixing the main body of the housing.

[0120] The aforementioned inert gas supply unit is installed on the aforementioned positioning unit.

[0121] <Project 7>

[0122] According to the welding apparatus described in any one of items 1 to 6, among which,

[0123] The length of the nozzles mentioned above is 100mm or more.

[0124] <Project 8>

[0125] A method for manufacturing an energy storage device, the energy storage device comprising a generally rectangular shell body having an opening on at least one side, and a generally rectangular sealing plate that blocks the opening, wherein...

[0126] The manufacturing method of the above-mentioned energy storage device includes:

[0127] The assembly process involves installing the sealing plate onto the opening of the housing body; and

[0128] During the welding process, inert gas is supplied towards the boundary between the main body of the shell and the sealing plate, i.e., the laser irradiation area, while the laser is directed to travel along the laser irradiation area.

[0129] In the above welding process, the inert gas is supplied from a slit-shaped nozzle extending along at least one side of the laser irradiation area, and the inert gas before being supplied to the nozzle is passed through a rectifier component that is a porous body.

[0130] <Project 9>

[0131] According to the manufacturing method of the energy storage device described in Project 8, among which,

[0132] The oxygen concentration around the laser irradiation area in the above welding process is controlled to be below 2%.

Claims

1. A welding apparatus for welding a generally rectangular shell body having an opening on at least one side to a generally rectangular sealing plate that blocks said opening, wherein, The welding apparatus includes: The laser irradiation section causes the laser to travel along the boundary between the housing body and the sealing plate, i.e., the laser irradiation area; and An inert gas supply unit supplies inert gas toward the laser irradiation area. The inert gas supply unit includes: A chamber, having an internal space; A supply pipe supplies the inert gas to the interior space of the chamber; A slit-shaped nozzle, communicating with the supply tube via the internal space, and extending along at least one side of the laser irradiation area; and The rectifier is a porous body housed in the internal space in a manner that separates the supply pipe from the nozzle.

2. The welding apparatus according to claim 1, wherein, The rectifier component is a mesh sheet.

3. The welding apparatus according to claim 2, wherein, The rectifying component is a wound or laminated body of the mesh sheet.

4. The welding apparatus according to claim 1, wherein, The rectifying component is a perforated plate with through holes for the inert gas to pass through.

5. The welding apparatus according to claim 1, wherein, The laser irradiation area has a first region extending along the long side of the housing body. The nozzle extends along the first region.

6. The welding apparatus according to claim 1, wherein, The welding device also includes a positioning part for fixing the main body of the housing. The inert gas supply unit is installed on the positioning unit.

7. The welding apparatus according to claim 1, wherein, The length of the nozzle is 100mm or more.

8. A method for manufacturing an energy storage device, the energy storage device comprising a generally rectangular shell body having an opening on at least one side, and a generally rectangular sealing plate blocking the opening, wherein, The manufacturing method of the energy storage device includes: The assembly process involves installing the sealing plate onto the opening of the housing body; and During the welding process, inert gas is supplied towards the boundary between the main body of the housing and the sealing plate, i.e., the laser irradiation area, while the laser is directed to travel along the laser irradiation area. In the welding process, the inert gas is supplied from a slit-shaped nozzle extending along at least one side of the laser irradiation area, and the inert gas before being supplied to the nozzle is passed through a rectifier component that is a porous body.

9. The method for manufacturing an energy storage device according to claim 8, wherein, The oxygen concentration around the laser irradiation area in the welding process is controlled to be below 2%.

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