Method for manufacturing a storage device

Abstract

To provide a manufacture method by which at the time of laser welding of a lid assembly obtained by integral molding of a lid, a terminal member and a resin insulating member, and a case body, deterioration of the insulating member is suppressed and a battery having high welding strength is achieved.SOLUTION: A manufacture method disclosed herein is a method for manufacturing an electrical storage device, which includes steps of: preparing a case body 11 in which a peripheral part 12e of an opening is a flat surface, and a lid assembly obtained by integral molding of a lid 15, a terminal member 30 and an insulating member 40; attaching the lid assembly to the opening of the case body 11; and irradiating the boundary of the peripheral part 12e and an outer edge part 15e with laser light from an outer surface 17 side of the lid 15. The lid assembly is placed so that an inclined part 15s becomes thinner from an outer surface 17 toward the boundary with the case body 11, and the outer surface 17 of the lid 15 is placed at a higher place than the peripheral part 12e of the opening, and the inner surface 16 of the lid 15 is placed at a lower place than the peripheral part 12e of the opening.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a method for manufacturing a power storage device.

Background Art

[0002] Conventionally, a battery is known that includes an electrode body, a case body that houses the electrode body, a lid that seals an opening of the case body and has a terminal mounting hole, and a terminal member mounted in the terminal mounting hole of the lid. The above-described case body and lid are sealed by welding, for example, by laser welding.

[0003] For example, Patent Document 1 describes welding an exterior can having an opening end surface of the exterior can inclined outward and downward from a terminal member and a lid. Patent Document 2 discloses performing laser welding on a battery housing having a step on the inner wall of the opening portion where the lid can be installed, and when the lid is installed on the step, the position of the upper surface of the lid is higher than the upper end portion of the opening portion. Patent Document 3 describes that a terminal is mounted on a metal lid via a gasket, and the lid is fitted so as to be higher than the upper end surface of a metal case and laser welded. Further, Patent Document 4 describes that between a battery can and a battery lid, a lateral boundary surface (Fx) intersecting in the height direction of the side wall portion and a longitudinal boundary surface (Fy) intersecting the lateral boundary surface and extending along the height direction of the side wall portion are formed, and at least a part of the lateral boundary surface and at least a part of the longitudinal boundary surface are welded by a laser (EB) irradiated in the longitudinal direction along the height direction of the side wall portion.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0005] In recent high-energy density batteries, a lid assembly in which a lid, a terminal member, and a resin insulating member are integrally molded is used. In such a lid assembly, the distance between the outer edge of the lid and the insulating member tends to be narrow from the viewpoint of improving the adhesion strength. When applying the techniques disclosed in Patent Documents 1 to 4 to welding and joining the above-described lid assembly and the case body, since the laser welding location and the resin insulating member are close to each other, the insulating member may be charred. As a result, the insulating member may deteriorate, leading to a decrease in insulation performance and a decrease in the airtightness of the battery.

[0006] Further, for example, as disclosed in Patent Document 1, when an inclination is provided on the opening end surface of the outer can, the area irradiated with the laser light is small and the amount of melted metal is reduced. Therefore, there is still room for improvement from the viewpoint of welding strength.

[0007] The present invention has been made in view of such problems, and provides a manufacturing method for realizing a battery in which deterioration of an insulating member is suppressed and welding strength is high during laser welding of a lid assembly in which a lid, a terminal member, and a resin insulating member are integrally molded, and a case body.

Means for Solving the Problems

[0008] The manufacturing method disclosed herein is a method for manufacturing a power storage device including a battery case having a bottomed case body with one side open, a lid body having a terminal mounting hole and sealing the opening, an electrode body housed in the battery case, a terminal member having one end electrically connected to the electrode body inside the battery case and the other end inserted through the terminal mounting hole and exposed outside the lid body, and a resin insulating member insulating the outer surface of the lid body, which is the outer surface of the battery case in a state where the opening is sealed, and the terminal member. Such a manufacturing method includes a step of preparing a case body having a peripheral edge of the opening that is flat, and a lid assembly in which the lid body, the terminal member, and the insulating member are integrally molded, a step of mounting the lid assembly on the opening of the case body, and a step of irradiating laser light from the outer surface side of the lid body toward a boundary between the peripheral edge and the outer edge, and laser-welding the case body and the lid assembly. Here, the lid body of the lid assembly prepared in the preparing step has an inclined portion that thins from the central side of the lid body toward the outer edge at least in a region where the outer edge of the lid body and the insulating member are closest to each other. In the mounting step, the lid assembly is arranged such that the inclined portion thins from the outer surface toward the boundary with the case body, and the outer surface of the lid body is higher than the peripheral edge of the opening, and the inner surface of the lid body is arranged at a position lower than the peripheral edge of the opening.

[0009] According to such a configuration, the laser light irradiated from the outside of the lid body is reflected by the inclined portion and is likely to be reflected in a direction away from the insulating member. Therefore, even when the insulating member and the outer edge of the lid body are close to each other, burning of the insulating member can be suppressed. Further, since the peripheral edge of the opening of the case body is flat, the area irradiated with the laser light increases, and the amount of melted metal can be increased. Thereby, the welding strength can be increased. Therefore, deterioration of the insulating member can be suppressed, and a battery with high welding strength can be realized.

Brief Description of the Drawings

[0010]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0011] Hereinafter, embodiments of the technology disclosed herein will be described with reference to the drawings. In addition, matters other than those specifically mentioned in this specification, which are necessary for implementing the technology disclosed herein (for example, general configurations and manufacturing processes of batteries that do not characterize the technology disclosed herein, etc.) can be grasped as design matters of those skilled in the art based on the prior art in the relevant field. The technology disclosed herein can be implemented based on the content disclosed in this specification and common general knowledge in the relevant field.

[0012] In this specification, the “power storage device” refers to a device in which a charge carrier moves between a pair of electrodes (a positive electrode and a negative electrode) through an electrolyte, thereby causing a charge and discharge reaction. Such power storage devices include secondary batteries such as lithium-ion secondary batteries, nickel-metal hydride batteries, and nickel-cadmium batteries; capacitors such as lithium-ion capacitors and electric double-layer capacitors. Hereinafter, as an example of a power storage device manufactured by the manufacturing method disclosed herein, a lithium-ion secondary battery among the above-described power storage devices will be taken as an example to describe an embodiment of the technology disclosed herein. Further, hereinafter, first, the configuration of the lithium-ion secondary battery will be described, and then the manufacturing method disclosed herein will be described.

[0013] <Battery 100> FIG. 1 is a perspective view of the battery 100. FIG. 2 is an exploded perspective view for explaining the configuration of the battery 100. In the following description, the reference signs L, R, F, Rr, U, and D in the drawings represent left, right, front, rear, top, and bottom, respectively. Also, the reference sign X in the drawings indicates the "short side direction of the battery", the reference sign Y indicates the "long side direction of the battery", and the reference sign Z indicates the "vertical direction of the battery". However, these are merely directions for convenience of explanation and do not limit the installation form of the battery in any way.

[0014] As shown in FIGS. 1 and 2, the battery 100 includes a battery case 10, an electrode body 20, a terminal member 30, and an insulating member 40. Although not shown, the battery 100 further includes an electrolytic solution here. In FIG. 2, an assembly component (hereinafter, also referred to as "lid assembly 15A") in which the terminal member 30 and the insulating member 40 are integrally formed on the lid body 15 of the battery case 10 is separated from other components and shown. Further, in FIG. 2, with respect to the electrode on one side (the right side in FIG. 2), the lid body 15, the terminal member 30, and the insulating member 40 are separated and shown.

[0015] The battery case 10 includes a case main body 11 and a lid body 15. As shown in FIG. 1, the battery case 10 has an outer shape of a flat rectangular parallelepiped (square) here. The material of the battery case 10 may be the same as that conventionally used and is not particularly limited. The battery case 10 (the case main body 11 and the lid body 15) is made of, for example, aluminum, aluminum alloy, stainless steel, iron, iron alloy, or the like. The battery case 10 is made of aluminum here.

[0016] As shown in Fig. 2, the case body 11 is a housing that accommodates the electrode body 20 and the electrolytic solution. The case body 11 is a bottomed and rectangular container having an opening 12 on one side (here, the upper surface). The opening 12 is substantially rectangular here. As shown in Fig. 1, the case body 11 includes a rectangular bottom surface 11a having a long side and a short side, a pair of long side walls 11b extending upward from the long side of the bottom surface 11a and facing each other, and a pair of short side walls 11c extending upward from the short side of the bottom surface 11a and facing each other. The long side wall 11b is an example of the first side wall, and the short side wall 11c is an example of the second side wall. Note that the case body is not particularly limited as long as it is a bottomed container having an opening on one side. For example, the case body may be a bottomed cylindrical case.

[0017] Here, the lid body 15 is rectangular and is a plate-like member that seals the opening 12 of the case body 11. The outer shape of the lid body 15 is smaller than the opening 12 of the case body 11. The lid body 15 faces the bottom surface 11a of the case body 11. The lid body 15 has an inner surface 16 facing the inner side of the battery 100 (that is, the side facing the electrode body 20) and an outer surface 17 facing the outer side of the battery 100. The lid body 15 has two terminal mounting holes 18 penetrating through the inner surface 16 and the outer surface 17. The terminal mounting holes 18 are provided one by one at both ends in the long side direction Y of the lid body 15. One terminal mounting hole 18 on one side (the left side in Fig. 2) is for the positive electrode, and the other terminal mounting hole 18 on the other side (the right side in Fig. 2) is for the negative electrode. From the viewpoint of durability and the like, the average thickness (average plate thickness) of the lid body 15 is preferably generally 0.3 mm or more, for example, 0.5 mm or more, and from the viewpoints of cost and energy density, it is preferably generally 2 mm or less, for example, 1.5 mm or less.

[0018] As shown in FIG. 1, the lid 15 is provided with a liquid injection hole (not shown) and a gas discharge valve 15h. The liquid injection hole is a through hole for injecting an electrolytic solution into the battery case 10 after the lid 15 is assembled to the case body 11. The liquid injection hole is sealed by a sealing member (not shown) after the injection of the electrolytic solution. The gas discharge valve 15h is a thin-walled portion configured to break when the pressure in the battery case 10 reaches a predetermined value or more and discharge the gas in the battery case 10 to the outside.

[0019] The lid assembly 15A is a member in which the lid 15 having a terminal mounting hole 18, a terminal member 30, and an insulating member 40 are integrally formed. The lid assembly 15A is mounted so as to close the opening 12 of the case body 11. Specifically, the inner wall 11d of the side wall of the case body 11 and the side surface of the lid 15 are butted against each other. As will be described later, the lid assembly 15A is arranged such that the outer surface 17 of the lid 15 is positioned higher than the peripheral edge portion 12e of the opening 12, and the inner surface 16 is positioned lower than the peripheral edge portion 12e of the opening 12, and the welding process is performed. The battery case 10 is sealed by performing welding and joining in a state where the opening 12 of the case body 11 is completely closed by the lid 15. A welded portion 50 formed by welding is formed in a predetermined region including a part of the boundary between the lid assembly 15A and the case body 11 (that is, the opposing surfaces of both members).

[0020] Figure 3 is a plan view when viewing FIG. 1 from the upper surface side. As shown in FIG. 3, the welded portion 50 is located on the outer surface 17 side of the lid body 15. The welded portion 50 is formed continuously in a substantially annular shape along the boundary between the outer edge portion 15e of the case body 11 and the lid body 15 in plan view. Here, as shown in FIG. 3, the terminal member 30 and the insulating member 40 are respectively provided at both ends in the long side direction Y. For this reason, the welded portion 50 is close to the insulating member 40 at both ends in the long side direction Y. The welded portion 50 is closest to the insulating member 40 in the regions A at both ends in the long side direction Y here. The region A is a range of length substantially equal to the length of the insulating member 40 in the long side direction Y (allowing an error of about ±1 mm). The region A is an example of "the region where the outer edge portion of the lid body and the insulating member are closest to each other". Although not particularly limited, in the region A, the distance between the welded portion 50 and the insulating member 40 can be generally 5 mm or less, typically 3 mm or less, for example, about 1 to 2 mm.

[0021] Figure 4 is a cross-sectional view taken along line IV-IV of FIG. 1. In FIG. 4, only one long side wall 11b of the case body 11 is shown, and the other long side wall 11b is omitted. As shown in FIG. 4, the case body 11 may include a support portion 11e that protrudes from the inner wall 11d toward the inside of the case. The support portion 11e is a part for arranging the lid body 15 at a desired position. For example, when the lid body 15 is placed on the support portion 11e, welding can be performed in a state where the outer surface 17 of the lid body 15 is arranged at a position higher than the peripheral edge portion 12e of the opening 12, and the inner surface 16 is arranged at a position lower than the peripheral edge portion 12e of the opening 12. The support portion 11e may be provided on the entire circumference of the opening 12 of the case body 11, or may be provided only on the inner surface of the short side wall 11c. Alternatively, the support portions 11e may be respectively provided at the four corners of the case body 11.

[0022] The electrode body 20 is housed inside the case body 11. The electrode body 20 is, for example, resin It is housed in the case body 11 while being covered with an insulating film (not shown) or the like. The electrode body 20 includes a positive electrode sheet, a negative electrode sheet, and a separator sheet disposed between the positive electrode sheet and the negative electrode sheet. Here, the electrode body 20 is a wound electrode body in which a strip-shaped positive electrode sheet and a strip-shaped negative electrode sheet are laminated in an insulated state via two strip-shaped separator sheets and wound in the longitudinal direction around a winding axis. However, the electrode body 20 may be a laminated electrode body in which a rectangular positive electrode and a rectangular negative electrode are stacked in an insulated state. Note that the reference sign WD in FIG. 2 indicates the winding axis direction (which is also the width direction) of the electrode body 20.

[0023] The positive electrode sheet is a member in which a positive electrode active material layer containing a positive electrode active material is fixed on at least one surface of a positive electrode current collector (for example, aluminum foil). The configuration of the positive electrode sheet is not particularly limited and may be the same as that used in conventionally known batteries. As the positive electrode active material, conventionally known materials can be used without particular limitation. As an example, a lithium transition metal composite oxide can be mentioned. The negative electrode sheet is a member in which a negative electrode active material layer containing a negative electrode active material is fixed on at least one surface of a negative electrode current collector (for example, copper foil). The configuration of the negative electrode sheet is not particularly limited and may be the same as that used in conventionally known batteries. As the negative electrode active material, conventionally known materials can be used without particular limitation. As an example, a carbon material such as graphite can be mentioned. The separator sheet is an insulating resin sheet in which a plurality of fine through-holes through which charge carriers can pass are formed. The configuration of the separator sheet is not particularly limited and may be the same as that used in conventionally known batteries.

[0024] The electrode body 20 is housed inside the case body 11 such that the winding axis direction WD substantially coincides with the vertical direction Z. In other words, the electrode body 20 is disposed inside the battery case 10 in a direction in which the winding axis direction WD is substantially parallel to the long side wall 11b and the short side wall 11c and substantially orthogonal to the bottom surface 11a and the lid body 15.

[0025] The positive electrode sheet has a plurality of positive electrode tabs 21t protruding outward (the upper side in FIG. 2) from one end side in the winding axis direction WD. The positive electrode tab 21t is an area where the positive electrode active material layer is not formed. Further, the negative electrode sheet has a plurality of negative electrode tabs 22t protruding outward (the upper side in FIG. 2) from one end side in the winding axis direction WD. Although shown in a separated state in FIG. 2, in the completed product of the battery 100, the terminal members 30 are electrically joined to the positive electrode sheet and the negative electrode sheet, respectively.

[0026] As shown in FIGS. 1 and 2, one terminal member 30 is provided at each of both end portions in the long side direction Y of the lid body 15. As shown in FIG. 2, one end is disposed inside the battery case 10, and the other end is inserted through the terminal mounting hole 18 and disposed outside the lid body 15. The terminal member 30 on the positive electrode side is made of, for example, aluminum or an aluminum alloy. The terminal member 30 on the negative electrode side is made of, for example, copper or a copper alloy.

[0027] As shown in FIGS. 2 and 4, the terminal member 30 has an electrode body connection portion 31, a shaft portion 32, and an external connection portion 33. The electrode body connection portion 31 is disposed inside the battery case 10. The electrode body connection portion 31 is configured in a rectangular flat plate shape here and extends horizontally along the inner surface 16 of the lid body 15 as shown in FIG. 2. The end portion in the long side direction Y of the electrode body connection portion 31 is electrically connected to the positive electrode tab 21t or the negative electrode tab 22t of the electrode body 20 inside the battery case 10.

[0028] The shaft portion 32 is disposed between the electrode body connection portion 31 and the external connection portion 33 and is inserted through the terminal mounting hole 18. The shaft portion 32 extends upward from the electrode body connection portion 31. The external connection portion 33 is disposed so as to be exposed on the outer surface 17 of the battery case 10. The external connection portion 33 is provided above the shaft portion 32. The external connection portion 33 is configured to have a size that can be inserted through the terminal mounting hole 18. Due to the difference in size among the electrode body connection portion 31, the shaft portion 32, and the external connection portion 33, the shaft portion 32 is constricted with respect to the electrode body connection portion 31 and the external connection portion 33.

[0029] The insulating member 40 is a resin member that prevents conduction between the lid body 15 and the terminal member 30. The insulating member 40 is preferably made of a fluororesin such as perfluoroalkoxy alkane (PFA) or polytetrafluoroethylene (PTFE), or a synthetic resin material such as polyphenylene sulfide (PPS). An inorganic filler or the like may be added to the synthetic resin material. As shown in FIG. 4, the insulating member 40 has a first flange portion 41, a second flange portion 42, and a cylindrical portion 43. Here, the first flange portion 41, the second flange portion 42, and the cylindrical portion 43 are integrally formed.

[0030] The cylindrical portion 43 is located between the terminal mounting hole 18 and the shaft portion 32 of the terminal member 30. The cylindrical portion 43 insulates the terminal mounting hole 18 and the shaft portion 32. The first flange portion 41 extends horizontally along the inner surface 16 of the lid body 15. The first flange portion 41 insulates the inner surface 16 of the lid body 15 and the electrode body connection portion 31. The second flange portion 42 extends horizontally from the cylindrical portion 43 along the outer surface 17 of the lid body 15. The second flange portion 42 insulates the outer surface 17 of the lid body 15 and the external connection portion 33. The outer shapes of the first flange portion 41 and the second flange portion 42 are larger than the outer shapes of the electrode body connection portion 31 and the external connection portion 33 of the terminal member 30. As shown in FIGS. 3 and 4, the second flange portion 42 protrudes outside the terminal member 30 (external connection portion 33) in a plan view and is exposed to the outside.

[0031] As shown in FIG. 2, the lid assembly 15A is an assembly component in which the terminal member 30 and the insulating member 40 are assembled to the lid body 15 by insert molding (integral molding). In the lid assembly 15A, the terminal member 30 is fixed to the lid body 15 by the insulating member 40 without being caulked. Further, the terminal member 30 is fixed to the lid body 15 by being fixed by the insulating member 40 without directly contacting the lid body 15. Although not shown, the lid body 15 and the terminal member 30 may be provided with, for example, a roughened portion where a roughening treatment has been performed. Thereby, the lid body 15, the terminal member 30, and the insulating member 40 can be fixed more firmly.

[0032] <Method for manufacturing a battery> Hereinafter, the manufacturing method disclosed herein will be described. Such a manufacturing method includes at least a preparation step of preparing the case body 11 and the lid assembly 15A described above, a mounting step of mounting the lid assembly 15A on the case body 11, and a welding step of laser-welding the boundary between the opening 12 of the case body 11 and the peripheral edge of the lid body 15. In the preparation step, a case body 11 with a peripheral edge 12e of the opening 12 being flat and a lid assembly 15A including a lid body 15 having an inclined portion 15s are prepared. The lid assembly 15A is arranged such that the inclined portion 15s of the lid body 15 thins toward the boundary with the case body 11 from the outer surface 17. Further, the outer surface 17 of the lid body 15 is higher than the peripheral edge 12e of the opening 12, and the inner surface 16 of the lid body 15 is arranged at a position lower than the peripheral edge 12e of the opening 12. The manufacturing method disclosed herein is characterized by performing the preparation step, the mounting step, and the welding step as described above, and the other manufacturing processes may be the same as those in the prior art. Further, other steps may be included at any stage.

[0033] FIG. 5 is a longitudinal sectional view schematically showing the vicinity of the boundary between the case body 11 and the lid body 15 in the welding step. According to the manufacturing method disclosed herein, as shown by the thick arrow in FIG. 5, the laser light IL irradiated from the outer surface 17 side hits a part of the lid body 15 and a part of the peripheral edge 12e of the opening 12. The laser light IL hitting a part of the lid body 15 and the peripheral edge 12e of the opening 12 is reflected at the boundary as shown by the thin arrow in FIG. 5, and the reflected light RL can be reflected outward. Therefore, even when welding the region close to the insulating member 40, damage to the insulating member 40 can be suppressed. Further, by using the case body 11 with the peripheral edge 12e of the opening 12 being flat, the area irradiated with the laser light IL becomes larger, and a stronger welded portion 50 can be formed. According to such a manufacturing method, when laser-welding the lid assembly in which the lid body 15, the terminal member 30, and the resin insulating member 40 are integrally molded and the case body 11, deterioration of the insulating member 40 can be suppressed, and a battery 100 with high welding strength can be realized.

[0034] In the preparation process, the case body 11 and the lid assembly 15A are prepared. Further, other necessary members as described above are prepared. As the case body 11, a case is prepared in which the peripheral edge portion 12e of the opening 12 is a flat surface. More specifically, the peripheral edge portion 12e is a flat surface orthogonal to the thickness direction of the lid body 15.

[0035] The lid body 15 has an inclined portion 15s that is inclined such that the thickness of the lid body 15 decreases from the central side of the lid body 15 toward the outer edge portion 15e. The lid body 15 has a flat portion 15f (see FIG. 4) radially inside the inclined portion 15s. The average thickness of the lid body 15 in the inclined portion 15s is smaller than the average thickness of the lid body 15 in the flat portion 15f. Since the lid body 15 has the inclined portion 15s, the irradiated laser light IL hits the inclined portion 15s and scatters in the direction opposite to the insulating member 40, so that the insulating member 40 can be suitably protected from the laser light.

[0036] The inclined portion 15s has an inclined surface that is inclined at an inclination angle θ1 from the outer surface 17 toward the boundary between the lid body 15 and the case body 11 when abutted against the case body 11 in the mounting process described later. For example, as shown in FIG. 4, the inclined portion 15s may be inclined so as to become thinner as it moves away from the insulating member 40. The inclination angle θ1 is an inclination angle with respect to the outer surface 17 of the lid body 15 (which is the same as the horizontal plane here). Specifically, the inclination angle θ1 is the smaller angle among the angles formed by the extension line of the outer surface 17 of the lid body 15 and the extension line of the inclined portion 15s. In the inclined portion 15s, the inclination angle θ1 is constant here.

[0037] The tilt angle θ1 is not particularly limited as long as it is an angle that can preferably reflect the laser beam IL as described above. The tilt angle θ1 is at least 1° or more, preferably 5° or more, may be 10° or more, and more preferably 20° or more. The tilt angle θ1 is preferably 90° or less, for example 80° or less, and more preferably 60° or less. By setting the tilt angle θ1 to a predetermined value or more, the laser beam IL is less likely to be reflected toward the insulating member 40 during laser welding, and charring of the insulating member 40 can be suppressed at a higher level. By setting the tilt angle θ1 to a predetermined value or less, the molten metal is less likely to flow along the tilt during laser welding, and the weldability can be improved.

[0038] Although not particularly limited, the inclined portion 15s is preferably provided on the outer surface 17 side in the thickness direction of the lid body 15. Specifically, when the maximum thickness t of the lid body 15 (the length in the vertical direction Z. The same shall apply hereinafter) is taken as 100%, the inclined portion 15s is preferably provided in a region within 50% from the outer surface in the thickness direction, and may be provided in a region within 40% for example. Thereby, the reflected light of the laser beam irradiated from above can be preferably scattered, and the insulating member 40 can be protected. On the other hand, the inclined portion 15s is preferably not provided on the inner surface side in the thickness direction of the lid body 15. That is, when the maximum thickness t of the lid body 15 is taken as 100%, the inclined portion 15s is preferably not provided in a region less than 50% from the inner surface in the thickness direction. For example, the lid body 15 preferably has a surface parallel to the side wall of the case body 11 (here, the long side wall 11b) in a region less than 50% from the inner surface in the thickness direction in a longitudinal section along the thickness direction. Thereby, the gap between the lid body 15 and the case body 11 can be reduced. For this reason, for example, so-called "laser leakage" in which the laser directly enters the case from the gap at the boundary between the lid body 15 and the case body 11 can be preferably suppressed.

[0039] The method for forming the inclined portion 15s as described above is not particularly limited. For example, by performing cutting on the peripheral edge of the lid 15, a lid 15 having an inclined portion 15s with a desired shape can be produced. Alternatively, processing (coining) may be performed by hitting the outer edge from an oblique direction with jigs arranged on the outer surface side of the lid and the outside of the side wall. At this time, the metal (excess material) may move to the outer surface side and bulge slightly, or the excess material may flow to the lower side (inner surface side) of the side wall, but this is acceptable as long as the effects of the technology disclosed herein are not impaired.

[0040] The preparation process may include an insert molding (integral molding) process. In the insert molding process, the terminal member 30 and the insulating member 40 are integrated with the lid 15 to produce an assembly part (for example, the lid assembly 15A). The lid assembly 15A can be created by insert molding the lid 15, the terminal member 30, and the insulating member 40. Thereby, the number of parts can be reduced, and a conduction path can be formed more simply compared to the conventional method using rivets. The lid assembly 15A can be produced, for example, by a method including a part setting process, a positioning process, an upper mold setting process, an injection molding process, an upper mold release process, and a part removal process, using a molding die having a lower mold and an upper mold.

[0041] In the part setting process, after two terminal members 30 are inserted into the respective terminal mounting holes 18 of the lid 15, the lid 15 is mounted on the lower mold. In the positioning process, the terminal members 30 are positioned and fixed. In the upper mold setting process, the upper mold is mounted so as to sandwich the lid 15 and the terminal members 30 in the vertical direction together with the lower mold. In the injection molding process, first, the molding die is heated. Next, molten resin is injected into the molding die. The molten resin flows from the upper mold through the terminal mounting holes 18 to the lower mold. Thereafter, the molding die and the molded product are cooled. Thereby, the insulating member 40, the lid 15, and the terminal members 30 are integrated. In the upper mold release process, the upper mold is separated from the lower mold. In the part removal process, the molded product is removed from the lower mold.

[0042] When integrating the lid 15, the terminal member 30, and the insulating member 40 by insert molding, it is desirable to increase the contact area between the lid 15 and the insulating member 40 in order to enhance the adhesion. For this reason, the external connection portion 33 and / or the second flange portion 42 tend to be larger than before, and the insulating member 40 (more specifically, the second flange portion 42) and the welding location are likely to be close to the outer surface 17 of the lid 15. Therefore, it is particularly effective to apply the technology disclosed herein.

[0043] For example, when welding a substantially flat lid 15 and the case body 11 as shown in the figure, in the regions A (see FIG. 4) at both ends in the long side direction Y, the outer edge portion 15e of the lid 15 and the insulating member 40 are closest to each other. For this reason, in the technology disclosed herein, it is preferable that the lid 15 has the inclined portion 15s at least in the region A. Thereby, even when using the integrally molded lid assembly 15A, welding can be performed while suitably protecting the insulating member 40. The lid 15 may be provided with at least the inclined portion 15s in a region where the distance between the outer edge portion 15e of the lid 15 and the insulating member 40 is 3 mm or less (for example, 2 mm or less) during welding, for example. Preferably, the inclined portion 15s is formed continuously in a substantially annular shape along the boundary between the case body 11 and the lid 15. Thereby, the insulating member 40 can be protected more reliably.

[0044] In the mounting process, the lid assembly 15A is mounted on the opening 12 of the case body 11. At this time, as shown in FIG. 4, the lid assembly 15A is arranged such that the above-described inclined portion 15s has a thinner thickness of the lid 15 toward the boundary with the case body 11. Then, the outer surface 17 of the lid 15 is arranged at a position higher than the peripheral edge portion 12e of the opening 12, and the inner surface 16 of the lid 15 is arranged at a position lower than the peripheral edge portion 12e of the opening 12. Thereby, the laser beam IL is likely to suitably hit the inclined portion 15s, and the laser beam is likely to be reflected in a direction away from the insulating member 40.

[0045] Although not particularly limited, in the mounting step, it is preferable that the peripheral edge portion 12e of the opening 12 is disposed in the region on the inner surface side in the thickness direction of the lid body 15. That is, when the maximum thickness of the lid body 15 is taken as 100%, it is preferable that the peripheral edge portion 12e of the opening 12 is disposed in a region less than 50% from the inner surface 16 in the thickness direction. More preferably, the peripheral edge portion 12e of the opening 12 may be disposed in a region of 25% or more and less than 50% from the inner surface 16 in the thickness direction. Alternatively, when the maximum thickness of the lid body 15 is t, the distance from the peripheral edge portion 12e to the inner surface 16 of the lid body 15 with respect to the maximum thickness t may be (t / 4) to (t / 2). Thereby, while exerting the protective effect of the insulating member 40 by the inclined portion 15s, the area where the lid body 15 and the case body 11 come into contact can be sufficiently secured, and the weldability can be improved. Also, the above-described laser breakage can be preferably prevented.

[0046] The distance (the length in the vertical direction Z) between the outer surface 17 of the lid body 15 and the peripheral edge portion 12e of the opening 12 is not particularly limited because it varies depending on the size of the battery 100, the thickness of the lid body 15, the thickness of the case body 11, etc., but for example, it is preferably 0.05 mm or more and 0.6 mm or less, and more preferably 0.05 mm or more and 0.1 mm or less.

[0047] Although not particularly limited, the lid assembly 15A can be electrically connected to the electrode body 20 before being assembled with the case body 11. Specifically, the electrode body 20 is attached to the lid assembly 15A by electrically connecting the electrode body connection portion 31 of the terminal member 30 integrated with the lid body 15, the positive electrode tab 21t, and the negative electrode tab 22t. Then, after covering the electrode body 20 attached to the lid assembly 15A with an electrode body holder (not shown), it is preferably housed inside the case body 11. Here, it is housed inside the case body 11 so that the winding axis direction WD of the electrode body 20 substantially coincides with the vertical direction Z.

[0048] The method of arranging the lid assembly 15A and the case body 11 in the positions as described above is not particularly limited. For example, as shown in FIG. 4, on the inner wall 11d of the case body 11, a support portion 11e may be provided so that the lid body 15 is arranged at a desired position. Thereby, the lid body 15 can be arranged at a desired position by a simple method. Alternatively, by increasing the height of the electrode body 20 (the length in the vertical direction Z; the same applies hereinafter), the arrangement of the lid body 15 connected to the electrode body 20 may be adjusted, or by increasing the thickness of the lid body 15, the arrangement of the lid body 15 may be adjusted.

[0049] In the welding process, after the electrode body 20 is accommodated inside the battery case 10, the case body 11 and the lid assembly 15A (more specifically, the lid body 15) are laser-welded together by irradiating laser light onto the boundary between them. Thereby, a welded portion 50 is formed at the boundary between the case body 11 and the lid body 15.

[0050] In the manufacturing method disclosed herein, as shown in FIG. 5, the laser light IL is irradiated from the outer surface side of the case body 11 onto the boundary between the case body 11 and the lid body 15. Although not particularly limited, the angle formed between the laser irradiation direction and the outer surface 17 (horizontal plane) of the lid body 15 is preferably about 90 ± 10°, and may be about 90 ± 5°. The type of laser light and the conditions for laser welding may be the same as those for the laser welding method used in this type of battery, and are not particularly limited.

[0051] As shown by the thick arrow in Fig. 5, the laser light IL irradiated from the outer surface side hits a part of the lid body 15 and a part of the peripheral edge portion 12e of the opening 12. The reflected light RL of such laser light IL is difficult to be reflected in the direction of the insulating member 40. In the manufacturing method disclosed herein, the lid body 15 has an inclined portion 15s, and further, the outer surface 17 of the lid body 15 is disposed above the peripheral edge portion 12e of the opening 12, and the inner surface 16 is disposed below the peripheral edge portion 12e of the opening 12. Accordingly, it is presumed that due to the relationship between the incident angle and the reflection angle, the laser light IL is likely to hit the inclined portion 15s, and the laser light IL is reflected in a direction away from the insulating member 40. Also, although the diffused light DL of the irradiated laser light IL can be slightly reflected toward the inclined portion 15s, it is reflected again in the direction opposite to the insulating member 40 when hitting the inclined portion 15s. That is, according to the technology disclosed herein, the insulating member 40 can be protected from secondary reflected light (for example, diffused light) generated in the vicinity of the opening 12. Therefore, even when the welding portion and the insulating member 40 are close to each other, deterioration of the insulating member is preferably suppressed.

[0052] Fig. 6 is a longitudinal sectional view for explaining a welding process of a conventional battery. As shown in Fig. 6, when the peripheral edge portion 112e of the opening of the case body 111 has an inclined portion 112s, the irradiated laser light IL is irradiated to a part of the inclined portion 112s and a part of the lid body 115 (that is, the laser light is received at a point). For this reason, in the conventional technology shown in Fig. 6, the amount of melted metal is small and the welding strength is low. On the other hand, as shown in Fig. 5, in the manufacturing method disclosed herein, the peripheral edge portion 12e of the opening 12 is a flat surface, the lid body 15 is provided with an inclined portion 15s, and the outer surface 17 is disposed above the peripheral edge portion 12e. For this reason, the laser light IL is irradiated to a part of the inclined portion 15s and a part of the peripheral edge portion 12e (that is, the laser light can be received on a surface). Therefore, the amount of melted metal is large and the welding strength can be increased. As a result, when laser-welding the lid assembly 15A in which the lid body 15 having the terminal mounting hole 18, the terminal member 30, and the resin insulating member 40 are integrally formed and the case body 11, deterioration of the insulating member 40 is suppressed and a battery 100 having a high welding strength can be realized.

[0053] <Battery Applications> The battery manufactured by the manufacturing method disclosed herein can be used for various applications. For example, it can be suitably used as a power source (driving power source) for a motor mounted on vehicles such as passenger cars and trucks. The type of vehicle is not particularly limited, and examples include plug-in hybrid electric vehicles (PHEVs), hybrid electric vehicles (HEVs), battery electric vehicles (BEVs), etc. The battery can also be suitably used in the construction of a battery pack.

[0054] As described above, some embodiments of the present invention have been described, but the above embodiments are merely examples. The present invention can be implemented in various other forms. The present invention can be implemented based on the content disclosed herein and common general knowledge in the art. The technology described in the claims includes various modifications and changes of the above-exemplified embodiments. For example, it is possible to replace a part of the above-described embodiments with other modified forms, and it is also possible to add other modified forms to the above-described embodiments. Also, if its technical features are not described as essential, they can be appropriately deleted.

[0055] As described above, specific aspects of the technology disclosed herein include those described in the following items. Item 1: A battery case including a bottomed case body with one side open, a lid having a terminal mounting hole for sealing the opening, an electrode body housed in the battery case, a terminal member having one end electrically connected to the electrode body inside the battery case and the other end inserted through the terminal mounting hole and exposed outside the lid, a resin insulating member for insulating an outer surface on the surface of the lid and outside the battery case in a state where the opening is sealed, and the terminal member. A method for manufacturing a power storage device, comprising: a step of preparing a case body having a flat peripheral edge of the opening, and a lid assembly in which the lid body, the terminal member, and the insulating member are integrally molded; a step of attaching the lid assembly to the opening of the case body; and a step of irradiating laser light from the outer surface side of the lid body onto the boundary between the peripheral edge and the outer edge of the lid body to laser-weld the case body and the lid assembly, wherein the lid body of the lid assembly prepared in the preparation step has an inclined portion that thins from the central side of the lid body toward the outer edge at least in a region where the outer edge member and the insulating member of the lid body are closest to each other, and in the attachment step, the lid assembly is arranged such that the inclined portion thins from the outer surface toward the boundary with the case body, the outer surface of the lid body is higher than the peripheral edge of the opening, and the inner surface of the lid body is lower than the peripheral edge of the opening. Item 2: The case body prepared in the preparation step has a rectangular opening, a rectangular bottom surface facing the opening, a pair of first side walls extending from the bottom surface and facing each other, and a pair of second side walls extending from the bottom surface and facing each other. The lid assembly prepared in the preparation step has a rectangular lid body, and the inclined portion is provided over the entire circumference of the outer edge of the lid body. The manufacturing method according to Item 1. Item 3: The lid assembly prepared in the preparation step has the inclined portion provided in a region within 50% in the thickness direction from the outer surface when the maximum thickness of the lid body is set to 100%. The manufacturing method according to Item 1 or 2. Item 4: In the attachment step, when the maximum thickness of the lid body is set to 100%, the peripheral edge of the opening is arranged in a region within 25% or more and less than 50% in the thickness direction from the inner surface. The manufacturing method according to any one of Items 1 to 3.

Explanation of Reference Numerals

[0056] 10 Battery case 11 Case body 11a Bottom surface 11b Long side wall 11c Short side wall 11d Inner wall 11e Support part 12 Opening 12e Peripheral part 15 Cover body 15A Cover assembly 15e Outer edge part 15f Flat part 15h Gas discharge valve 15s Inclined part 16 Inner surface 17 Outer surface 18 Terminal mounting hole 20 Electrode body 21t Positive tab 22t Negative tab 30 Terminal member 31 Electrode body connection part 32 Shaft part 33 External connection part 40 Insulating member 41 First flange part 42 Second flange part 43 Cylindrical part 50 Welded part 100 Battery 111 Case body 112 Opening 112e Peripheral part 112s Inclined part 115 Cover body

Claims

1. A battery case including a bottomed case body with one side open, and a lid having a terminal mounting hole for closing the opening; An electrode body housed in the battery case; A terminal member having one end electrically connected to the electrode body inside the battery case and the other end inserted through the terminal mounting hole and exposed outside the lid; A resin insulating member on the surface of the lid for insulating the outer surface outside the battery case in a state of closing the opening and the terminal member; A method for manufacturing a power storage device, comprising: A step of preparing a case body with a peripheral edge of the opening being flat, and a lid assembly in which the lid, the terminal member, and the insulating member are integrally molded; A step of mounting the lid assembly on the opening of the case body; A step of irradiating laser light from the outer surface side of the lid to a boundary between the peripheral edge and the outer edge of the lid, and laser-welding the case body and the lid assembly; Including; Here, The case body prepared in the preparation step has a rectangular opening, a rectangular bottom surface facing the opening, a pair of first side walls extending from the bottom surface and facing each other, and a pair of second side walls extending from the bottom surface and facing each other; The lid of the lid assembly prepared in the preparation step has an inclined portion that thins from the central side of the lid toward the outer edge at least in a region where the outer edge of the lid and the insulating member are closest to each other; The lid assembly prepared in the preparation step has a rectangular lid, and the inclined portion is provided over the entire circumference of the outer edge of the lid; In the mounting step, the lid assembly is arranged such that the inclined portion thins from the outer surface toward the boundary with the case body; The outer surface of the lid is arranged at a position higher than the peripheral edge of the opening, and the inner surface of the lid is arranged at a position lower than the peripheral edge of the opening; A method for manufacturing a power storage device.

2. A battery case including a bottomed case body with one side open, and a lid having a terminal mounting hole for closing the opening; An electrode body housed in the battery case; A terminal member having one end electrically connected to the electrode body inside the battery case and the other end inserted through the terminal mounting hole and exposed outside the lid; An insulating member made of resin that insulates an outer surface of the lid body, which is on the outside of the battery case in a state where the opening is sealed, and the terminal member. A method for manufacturing a power storage device, comprising: Preparing a case body in which a peripheral edge of the opening is flat, and a lid assembly in which the lid body, the terminal member, and the insulating member are integrally molded. A step of attaching the lid assembly to the opening of the case body. A step of irradiating laser light from the outer surface side of the lid body to a boundary between the peripheral edge and an outer edge of the lid body, and laser-welding the case body and the lid assembly. Including Here, The lid body of the lid assembly prepared in the preparing step has an inclined portion that becomes thinner from the central side of the lid body toward the outer edge at least in a region where the outer edge of the lid body and the insulating member are closest to each other. The lid assembly prepared in the preparing step is provided with the inclined portion in a region within 50% in the thickness direction from the outer surface when the maximum thickness of the lid body is set to 100%. In the attaching step, the lid assembly is arranged such that the inclined portion becomes thinner from the outer surface toward the boundary with the case body. The outer surface of the lid body is disposed at a position higher than the peripheral edge of the opening, and the inner surface of the lid body is disposed at a position lower than the peripheral edge of the opening. A method for manufacturing a power storage device.

3. A battery case including a bottomed case body having an opening on one side, and a lid body having a terminal mounting hole and sealing the opening. An electrode body housed in the battery case. A terminal member having one end electrically connected to the electrode body inside the battery case and the other end inserted through the terminal mounting hole and exposed outside the lid body. An insulating member made of resin that insulates an outer surface of the lid body, which is on the outside of the battery case in a state where the opening is sealed, and the terminal member. A method for manufacturing a power storage device, comprising: Preparing a case body in which a peripheral edge of the opening is flat, and a lid assembly in which the lid body, the terminal member, and the insulating member are integrally molded. A step of attaching the lid assembly to the opening of the case body. A step of irradiating laser light from the outer surface side of the lid body to a boundary between the peripheral edge and an outer edge of the lid body, and laser-welding the case body and the lid assembly. Including Here, The lid of the lid assembly prepared in the preparation step has an inclined portion that thins from the central side of the lid toward the outer edge at least in a region where the outer edge of the lid and the insulating member are closest to each other. In the mounting step, the lid assembly is arranged such that the inclined portion thins from the outer surface toward the boundary with the case body. The outer surface of the lid is arranged at a position higher than the peripheral edge of the opening, and the inner surface of the lid is arranged at a position lower than the peripheral edge of the opening. In the mounting step, when the maximum thickness of the lid is taken as 100%, the peripheral edge of the opening is arranged in a region that is 25% or more and less than 50% in the thickness direction from the inner surface. A method for manufacturing a power storage device.

Images