Sealed structure

Abstract

To obtain a sealed structure capable of suppressing melting of a resin member in contact with a roughened portion due to heat transfer during welding of a case member.SOLUTION: A sealed structure 10A is a sealed structure in which a gap between a case member 20 accommodating an electrode assembly 30 and a terminal member 40 drawn out through an opening 24 of the case member 20 is sealed by an integrally molded resin member 60. In the sealed structure 10A, the case member 20 includes a first roughened portion 50 having a surface roughened to improve bonding strength with the resin member 60, the first roughened portion 50 being formed in at least part of a peripheral edge of the opening 24.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a sealing structure. [Background technology]

[0002] As a sealed structure between a case member containing an electrode body and a terminal member pulled out through an opening in the case member, a structure in which the gap between the case member and the terminal member is sealed by an integrally formed resin member is known (see, for example, Patent Document 1 and Patent Document 2).

[0003] Furthermore, Patent Documents 1 and 2 propose roughening part of the surface of the case member in order to improve the bonding strength between the case member and the resin member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-086813 [Patent Document 2] Japanese Patent Application Publication No. 2024-009544 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the above-mentioned Patent Documents 1 and 2, the roughened surface of the case member is provided at a position farthest from the periphery of the opening in the region where the case member is integrated with the resin member. Therefore, the roughened surface is located close to the welding point of the case member, and a portion of the resin member in contact with the roughened surface may melt due to heat transfer during welding. If the resin member in contact with the roughened surface melts, there is a risk that the sealing performance of the opening and the functionality of the holding member for holding the terminal member may be impaired.

[0006] In consideration of the above, an object of the present invention is to provide a sealed structure that prevents the resin member in contact with the roughened surface portion from melting due to heat transfer during welding of the case members. [Means for solving the problem]

[0007] The sealed structure of the first aspect of the present invention is a sealed structure in which a gap between a case member containing an electrode body and a terminal member pulled out through an opening in the case member is sealed by an integrally molded resin member, and the case member has a first roughened portion whose surface is roughened to improve the bonding strength with the resin member, and the first roughened portion is formed on at least a part of the periphery of the opening.

[0008] In the sealed structure of the first aspect of the present invention, the first roughened portion is formed on at least a part of the periphery of the opening of the case member. Therefore, the roughened portion is disposed at a position far from the welding point of the case member. This prevents the resin member in contact with the first roughened portion from melting due to heat transfer during welding of the case member.

[0009] The sealed structure of the second aspect of the present invention is the configuration described in the first aspect, wherein the terminal member has an axial portion passed through the opening and a flat portion provided on one axial end side of the axial portion and positioned outside the case member, and the flat portion has a second roughened portion whose surface is roughened to improve the bonding strength with the resin member, and the second roughened portion at least partially overlaps with the first roughened portion when viewed from the axial direction of the axial portion.

[0010] In a sealed structure according to a second aspect of the present invention, a second roughened surface is provided on a flat surface of the terminal member to improve bonding strength with the resin member. When viewed in the axial direction of the shank of the terminal member, the second roughened surface at least partially overlaps with the first roughened surface. Therefore, like the first roughened surface, the second roughened surface is located far from the welding point of the case member. This prevents the resin member in contact with the second roughened surface from melting due to heat transfer during welding of the case member. Furthermore, the first and second roughened surface portions are located close to the shank of the terminal member, thereby enhancing bonding strength with the resin member near the shank. This effectively prevents degradation of the sealing performance of the opening due to input of vibrations or the like via the shank of the terminal member, and a reduction in functionality as a holding member for holding the terminal member.

[0011] A third aspect of the sealed structure of the present invention is a configuration described in the first or second aspect, in which the first roughened portion has a plurality of annular portions arranged concentrically around the opening at the periphery of the opening.

[0012] However, when external vibrations are input to the terminal member via a bus bar or the like connected to the terminal member, cracks may occur on the resin member side, which has lower rigidity, in areas where the joining strength between the case member and the resin member is improved.

[0013] In the sealed structure of the third aspect of the present invention, the first roughened portion has a plurality of annular portions arranged concentrically around the opening. Therefore, since the annular portions are spaced apart radially, even if a crack occurs in one annular portion, the crack is prevented from spreading to the other annular portions. This allows the bonding strength between the case member and the resin member to be maintained for a long period of time.

[0014] The sealing structure of the fourth aspect of the present invention is configured as described in the first or second aspect, and a thick-walled portion having the thickest plate thickness in the case member is provided on the peripheral edge of the opening, and the thick-walled portion is provided in the peripheral edge including at least a portion that is more inward than the outermost end of the first roughened portion.

[0015] In the sealed structure of the fourth aspect of the present invention, when the case members are welded together, the thick-walled portion can disperse the heat that reaches the first roughened portion, thereby preventing the heat from concentrating on the first roughened portion, effectively preventing the resin member in contact with the roughened portion from melting.

[0016] The sealed structure of the fifth aspect of the present invention is configured as described in the first or second aspect, wherein the first roughened portion has a plurality of annular portions arranged concentrically around the opening at the periphery of the opening, and the thickness of the case member at the portion where the annular portions on the innermost periphery are provided is thinner than the thickness of the portion where the annular portions on the outermost periphery are provided.

[0017] In the sealed structure of the fifth aspect of the present invention, even if the heat generated during welding of the case member reaches the outermost annular portion near the welded location and melts a portion of the resin member in contact with the outermost annular portion, the inner annular portion can maintain the bonding strength between the case member and the resin member. Furthermore, since the thickness of the case member at the portion where the innermost annular portion is provided is thinner than the thickness of the portion where the outermost annular portion is provided, the mass of the case member can be reduced. Thus, this sealed structure can reduce the weight of the part while strengthening the bonding strength between the case member and the resin member. [Effects of the Invention]

[0018] As described above, the sealed structure according to the present invention can prevent the resin member in contact with the roughened portion from melting due to heat transfer during welding of the case members. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is an exploded perspective view of a battery to which a sealed structure according to an embodiment is applied; [Figure 2] 2 is an enlarged cross-sectional view of a case member taken along line 2-2 in FIG. 1. FIG. [Figure 3]10A and 10B are schematic diagrams for explaining dissolution of a resin member when welding a case member. [Figure 4] 10A and 10B are schematic diagrams for explaining vibration input via a shaft portion of a terminal member. [Figure 5] 3 is an enlarged cross-sectional view corresponding to FIG. 2, showing a first modified example of the sealing structure according to the embodiment. FIG. [Figure 6] 10 is an enlarged cross-sectional view corresponding to FIG. 2, showing a second modified example of the sealing structure according to the embodiment. FIG. [Figure 7] 10 is an enlarged cross-sectional view corresponding to FIG. 2, showing a third modified example of the sealing structure according to the embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] Hereinafter, a sealing structure according to an embodiment will be described with reference to the drawings. The sealing structure according to each embodiment is applied to a case member of a secondary battery, for example. The secondary battery may be, for example, a lithium-ion secondary battery that constitutes a battery module used as an on-board power source for an electric vehicle, a hybrid vehicle, or the like. In each drawing, arrow W indicates the width direction of the battery, arrow D indicates the depth direction of the battery, and arrow H indicates the height direction of the battery.

[0021] Hereinafter, with reference to FIGS. 1 and 2, a sealed structure 10A according to one embodiment and a battery 12 as a secondary battery to which the sealed structure 10A is applied will be described.

[0022] (Overall battery configuration) As shown in FIG. 1, the battery 12 has a case member 20, an electrode assembly 30, a terminal member 40, and a resin member 60.

[0023] (Case material) The case member 20 is composed of a case body 70 and a cover member 22 disposed in an opening 71 of the case body 70 .

[0024] Case body 70 is made of, for example, aluminum, and is formed in the shape of a rectangular box that is long in width direction W and has an open top. Lid member 22 is made of, for example, aluminum, and is formed in the shape of a rectangular plate that extends in width direction W. Lid member 22 has a plate thickness direction in height direction H, and has inner surface 22A that faces the internal space of case member 20 and outer surface 22B that faces the external space of case member 20. Lid member 22 is provided with safety valve 21A and cap 26 that closes injection port 21B.

[0025] Safety valve 21A opens when the internal pressure of case member 20 reaches a predetermined pressure, and discharges gas generated inside case member 20. Inlet 21B is formed as a through-hole that penetrates lid member 22 in the plate thickness direction. Inlet 21B is used when injecting electrolyte into case member 20. Cap 26 is attached to inlet 21B and hermetically sealed, for example, by laser welding.

[0026] The cover member 22 also has openings 24 at one and the other ends in the width direction W (see FIG. 2). The two openings 24 are formed as through holes that penetrate the cover member 22 in the plate thickness direction, and terminal members 40 (described later) are inserted through them. The shape of the openings 24 is not particularly limited and can be selected appropriately from a circular or rectangular shape, but a circular shape is preferable in terms of suppressing local stress concentration around the openings 24. The shape of the openings 24 in this embodiment is circular.

[0027] The electrode body 30 is housed inside the case body 70. With the electrode body 30 housed in the case body 70, the lid member 22 is attached by, for example, laser welding so as to close the opening 71 of the case body 70.

[0028] (electrode body) The electrode body 30 includes a power generating element 31 , a negative electrode current collecting portion 32 , and a positive electrode current collecting portion 33 .

[0029] The power generating element 31 is housed in the case body 70 while being covered with, for example, an insulating film (reference numeral omitted). The power generating element 31 includes a positive electrode sheet (not shown), a negative electrode sheet (not shown), and a separator sheet (not shown) disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet, the negative electrode sheet, and the separator sheet are each long, strip-shaped members. The power generating element 31 is formed by laminating the positive electrode sheet, the negative electrode sheet, and the separator sheet and winding them inside the case body 70.

[0030] The positive electrode sheet is a member in which a positive electrode active material layer containing a positive electrode active material is formed on both sides of a current collector of a predetermined width and thickness. The current collector is a metal foil, and in this embodiment, it is an aluminum foil. The positive electrode active material can be any known material. For example, in a lithium-ion secondary battery, it is a material that can release lithium ions during charging and absorb lithium ions during discharging, such as a lithium transition metal composite material.

[0031] The negative electrode sheet is a member in which a negative electrode active material layer containing a negative electrode active material is formed on both sides of a current collector of a predetermined width and thickness. The current collector is a metal foil, and in this embodiment, it is copper foil. Known materials can be appropriately used as the negative electrode active material. For example, in a lithium-ion secondary battery, it is a material such as natural graphite that can absorb lithium ions during charging and release the absorbed lithium ions during discharging.

[0032] The separator sheet may be, for example, a porous resin sheet having the required heat resistance and allowing the electrolyte to pass through. Known materials may also be used as the separator sheet.

[0033] One end of the positive electrode sheets is assembled on one side in the width direction W of the electrode body 30 to form a positive electrode current collector 33. A positive electrode terminal member 40 is welded to this positive electrode current collector 33, as will be described later.

[0034] One end of the negative electrode sheets is assembled on the other side in the width direction W of the electrode body 30 to form a negative electrode current collector 32. A negative electrode terminal member 40 is welded to this negative electrode current collector 32, as will be described later.

[0035] (Terminal material) The terminal member 40 has a negative electrode side terminal member 42 and a positive electrode side terminal member 43. The negative electrode side terminal member 42 is a terminal member that is electrically connected to the negative electrode current collector 32 of the electrode body 30. The negative electrode side terminal member 42 is made of copper, for example. The positive electrode side terminal member 43 is a terminal member that is electrically connected to the positive electrode current collector 33 of the electrode body 30. The positive electrode side terminal member 43 is made of aluminum, for example.

[0036] The negative terminal member 42 and the positive terminal member 43 basically have the same configuration, and therefore the following description will focus on the configuration of the negative terminal member 42. When there is no need to particularly distinguish between the negative terminal member 42 and the positive terminal member 43, they may be simply referred to as terminal members 40.

[0037] Figure 2 is an enlarged cross-sectional view showing the state in which the cover member 22 of the case member 20 has been cut away, and shows the state in which the terminal member 40 connected to the electrode body 30 has been pulled out through the opening 24 of the cover member 22.

[0038] As shown in this figure, the terminal member 40 has an electrode assembly connecting portion 44 (see FIG. 1), a shaft portion 46, and a flat portion 48. Note that the electrode assembly connecting portion 44 is not shown in FIG.

[0039] The electrode body connection part 44 is disposed inside the case body 70 and is connected to the current collectors (negative electrode current collector 32, positive electrode current collector 33) of the electrode body 30. As shown in Fig. 1, the electrode body connection part 44 is formed in the shape of a long, narrow plate in the height direction H, and extends downward from the lower end of the shaft part 46.

[0040] The shaft portion 46 is provided above the electrode body connection portion 44 and is inserted into the opening 24 of the cover member 22. As shown in FIG. 2 , the shaft portion 46 is formed in a columnar shape with the height direction H as the axial direction A. The shaft portion 46 can be appropriately selected from a columnar shape such as a circular cylinder or a rectangular cylinder, but is preferably a columnar shape in order to prevent localized stress concentration around the opening 24 of the cover member 22. In one example of this embodiment, the shaft portion 46 is a columnar shape.

[0041] The flat surface 48 is provided above the shaft 46 and is disposed outside the cover member 22 (case member 20). The flat surface 48 is formed in a flat plate shape with the height direction H as the plate thickness direction, and has an inner surface 48A facing the outer surface 22B of the cover member 22 and an outer surface 48B facing the outside of the case member 20.

[0042] Although the electrode body connection portion 44, the shaft portion 46, and the flat portion 48 are formed as separate bodies here, some or all of these members may be formed integrally.

[0043] A plate-shaped external connection terminal 28 is superimposed on the outer surface 48B of the flat portion 48. The external connection terminal 28 is a terminal member that relays the connection between the terminal member 40 and a bus bar (not shown), and is electrically connected to the flat portion 48. The external connection terminal 28 is formed, for example, in a plate shape having the same dimensions and shape as the flat portion 48 of the terminal member 40. The external connection terminal 28 is also made of aluminum. It is not essential to provide the external connection terminal 28 on the flat portion 48, and the external connection terminal 28 may be omitted.

[0044] The terminal member 40 is integrally formed with the cover member 22 via a resin member 60 serving as an insulating material. That is, the case member 20 has a sealed structure 10A in which the gap between the terminal member 40 drawn out through the opening 24 of the cover member 22 and the case member 20 is sealed by the integrally molded resin member 60.

[0045] (roughened surface) Here, the case member 20 and the terminal member 40 have a plurality of roughened portions 50 that roughen the surfaces to improve the bonding strength with the resin member 60. The roughened portions 50 are a surface treatment that forms irregularities on the surfaces of the case member 20 and the terminal member 40 to enhance the anchoring effect with the resin member that is integrally molded, thereby improving the bonding strength.

[0046] The roughened portion 50 of this embodiment is made up of a first roughened portion 50A, a second roughened portion 50B, and a third roughened portion 50C.

[0047] (1st roughened part) The first roughened portion 50A is formed on the outer surface 22B of the cover member 22 along the periphery of the opening 24 of the cover member 22. The first roughened portion 50A is formed all around the periphery of the opening 24, and forms a circular band-like annular portion in plan view (as viewed from the axial direction A).

[0048] The peripheral edge of the opening 24 is located at the position on the outer surface 22B of the cover member 22 that is farthest from the welding point between the cover member 22 and the case body 70.

[0049] It is not essential that first rough surface portion 50A be formed along the entire periphery of opening 24, but may be formed only on a part of the periphery of opening 24.

[0050] (2nd roughened part) The second roughened portion 50B is formed on the flat surface 48 of the terminal member 40. Specifically, the second roughened portion 50B is formed on the inner surface 48A of the flat surface 48 so as to surround the shaft portion 46. When viewed from the axial direction A, the second roughened portion 50B is formed all the way around the periphery of the opening 24, and forms a circular band-like annular portion in plan view (when viewed from the axial direction A).

[0051] The inner diameter of the second roughened portion 50B is set smaller than the inner diameter of the opening 24. Therefore, at least a portion of the second roughened portion 50B is disposed inside the opening 24 in plan view (as viewed from the axial direction A). Furthermore, at least a portion of the second roughened portion 50B overlaps with the first roughened portion 50A in plan view. In FIG. 2, S1 indicates the region where the first roughened portion 50A and the second roughened portion 50B overlap in the axial direction A.

[0052] The position of the second roughened portion 50B on the flat portion 48 of the terminal member 40 (i.e., the position of the peripheral edge of the shaft portion 46 when viewed from the axial direction A) is the position on the inner surface 22A of the flat portion 48 that is farthest from the welding point between the cover member 22 and the case body 70.

[0053] It is not necessary for the second roughened portion 50B to be formed all the way around the periphery of the opening 24 when viewed from the axial direction A, but it may be formed only in a portion of the periphery of the opening 24 when viewed from the axial direction A.

[0054] (Third roughened part) The third roughened portion 50C is formed on the inner surface 22A of the cover member 22 along the periphery of the opening 24 of the cover member 22. The third roughened portion 50C is formed all around the periphery of the opening 24, and forms a circular band-like annular portion in plan view (when viewed from the axial direction A).

[0055] The radial width of the third roughened surface portion 50B may be set to be equal to or larger than the radial width of the first roughened surface portion 50A. In this embodiment, the third roughened surface portion 50B at least partially overlaps with the first roughened surface portion 50A and the second roughened surface portion 50B in a plan view (as viewed from the axial direction A). In FIG. 2, the region where the first roughened surface portion 50A and the third roughened surface portion 50C overlap in the axial direction A is indicated by S2, and the region where the second roughened surface portion 50B and the third roughened surface portion 50C overlap in the axial direction A is indicated by S3.

[0056] The position of this third roughened surface portion 50C is the position on the inner surface 22A of the cover member 22 that is farthest from the welding point between the cover member 22 and the case body .

[0057] It is not essential that third rough surface portion 50A be formed along the entire periphery of opening 24, but may be formed only on a part of the periphery of opening 24.

[0058] (Resin parts) Next, the resin member 60 will be described. The resin member 60 is an insulating material that ensures insulation between the case member 20 and the terminal member 40. The resin member 60 is composed of a cylindrical portion 62, a first flange portion 64, a second flange portion 66, and a frame-shaped portion 68. The cylindrical portion 62, the first flange portion 64, the second flange portion 66, and the frame-shaped portion 68 are integrally molded with the cover member 22 and the terminal member 40 by resin injection molding.

[0059] The cylindrical portion 62 is interposed between the opening 24 of the cover member 22 and the shaft portion 46 of the terminal member 40, and has a cylindrical shape. The first flange 64 is provided on the upper side of the cylindrical portion 62 and is interposed between the cover member 22 and the flat portion 48 of the terminal member 40. The first flange 64 has a flange shape that extends horizontally along the outer surface 22B of the cover member 22. The second flange 66 is provided on the lower side of the cylindrical portion 62 and has a flange shape that extends horizontally along the inner surface 22A of the cover member 22. The frame-shaped portion 68 stands upward from the outer periphery of the upper surface of the first flange portion 64, and is arranged so as to cover the flat surface portion 48 of the terminal member 40 and the outer periphery of the external connection terminal 28. In a plan view, the frame-shaped portion 68 has a frame shape that surrounds the flat surface portion 48 of the terminal member 40.

[0060] The resin member 60 is formed of, for example, PPS resin. However, the resin member 60 is not limited to PPS resin, and may be any material that has moldability, insulating properties, sealing properties, and resistance to electrolyte. Considering the difference between the temperature during molding of the resin member 60 and the temperature during use of the battery 12, it is preferable that the linear expansion coefficient of the lid member 22 and the linear expansion coefficient of the resin member 60 are close to each other. Therefore, in addition to PPS resin, a filler for adjusting the linear expansion coefficient may be added to the resin member 60.

[0061] [Dissolution of resin material during welding of case components] In the battery 12, when the case members 20 are welded, heat transfer from the welded portions may cause part of the resin member 60 to melt.

[0062] FIG. 3 schematically shows heat propagation during welding of the case member 20. As shown in this figure, the outer periphery of the lid member 22 of the case member 20 is welded to the opening 71 of the case body 70. At this time, heat from welding propagates from the outer periphery where the welded portion (see positions Q1 and Q2 in FIG. 3) is provided to the lid member 22 toward the inside (the opening 24 side). At this time, the end of the resin member 60 farthest from the opening 24 of the lid member 22 is positioned closest to the welded portion, so there is a possibility that part of the resin member 60 will melt due to heat transfer during welding. In this embodiment, the outer periphery of the first flange 64 of the resin member 60 is closest to the welded portion of the lid member 22, and therefore forms a melting caution zone X where there is a high risk of melting.

[0063] On the other hand, the inner peripheries of the cylindrical portion 62, the first flange portion 64 and the second flange portion 66 of the resin member 60 are the farthest from the welding point of the cover member 22, and therefore form a melting avoidance area Y where the risk of melting is low.

[0064] In this embodiment, the first roughened portion 50A, the second roughened portion 50B, and the third roughened portion 50C are formed in the melting avoidance zone Y where the risk of melting is low. This prevents the resin member 60 in contact with the roughened portion 50 from melting due to heat transfer during welding of the case member 20.

[0065] [Vibration input via the shaft of the terminal member] In the battery 12, vibrations caused when the vehicle is running may be transmitted to a bus bar (not shown) connected to the upper side of the terminal member 40 and input to the battery 12 via the shaft portion 46 of the terminal member 40.

[0066] FIG. 4 schematically shows vibration F input via the shaft portion 46. As shown in this figure, vibration F input to the battery 12 is input along the axial direction A of the shaft portion 46. Therefore, in known sealed structures, a roughened portion is provided on the outer circumferential surface of the shaft portion 46 to improve the bonding strength between the shaft portion 46 and the resin member 60 (see, for example, Patent Documents 1 and 2). However, in such known roughened portions, the bond between the terminal member 40 and the resin member 60 is characterized by being strong against input in the tensile direction perpendicular to the axial direction A but weak against input in the shear direction along the axial direction A. For this reason, the known roughened portions cannot be said to be optimally positioned in terms of maintaining bonding strength against vibration input via the shaft portion 46.

[0067] In this embodiment, the first roughened portion 50A, the second roughened portion 50B, and the third roughened portion 50C are formed on the surfaces of the cover member 22 and the terminal member 40 facing the axial direction A. Therefore, vibrations input along the axial direction A of the shaft portion 46 act as tensile inputs to each roughened portion. This arrangement can be said to be optimized in terms of maintaining bonding strength against vibrations input via the shaft portion 46.

[0068] (Action and effect) As described above, in the sealed structure 10A according to the first embodiment, the first roughened portion 50A is formed on the periphery of the opening 24 of the cover member 22 (case member 20). Therefore, the first roughened portion 50A is disposed at a position far from the welding location of the case member 20. This prevents the resin member 60 in contact with the first roughened portion 50A from melting due to heat transfer during welding of the case member 20.

[0069] In this embodiment, a second roughened surface portion 50B is provided on the flat surface portion 48 of the terminal member 40. When viewed from the axial direction A of the shaft portion 46 of the terminal member 40, the second roughened surface portion 50B at least partially overlaps with the first roughened surface portion 50A. Therefore, like the first roughened surface portion 50A, the second roughened surface portion 50B is located far from the welding location of the case member 20. This prevents the resin member 60, which is in contact with the second roughened surface portion 50B, from melting due to heat transfer during welding of the case member 20. Furthermore, because the first roughened surface portion 50A and the second roughened surface portion 50B are located close to the shaft portion 46 of the terminal member 40, the bonding strength with the resin member 60 is enhanced near the shaft portion 46. This effectively prevents the resin member 60 from losing its sealing ability at the opening 24 due to input of vibrations or the like via the shaft portion 46 of the terminal member 40, or from losing its functionality as a holding member for holding the terminal member 40.

[0070] (First Modification) A sealed structure 10B according to a first modified example of the above embodiment will be described below with reference to Fig. 5. Note that the same components as those in the above embodiment will be given the same reference numerals and descriptions thereof will be omitted.

[0071] As shown in Fig. 5, this sealed structure 10B is characterized in that the cover member 22 has a thick portion 23 on the periphery of the opening 24. The other configurations are basically the same as those of the above embodiment. This thick portion 23 is provided on the inner surface 22A of the cover member 22 on the periphery of the opening 24, and protrudes downward from the inner surface 22A in a cylindrical shape. As a result, the thick portion 23 is the part of the cover member 22 that is set to have the greatest plate thickness.

[0072] The shaft portion 46 of the terminal member 40 is inserted inside the cylindrical thick-walled portion 23. Therefore, in this first modified example, the roughened portion 50 does not include the third roughened portion 50C in the above embodiment. That is, the roughened portion 50 is composed of a first roughened portion 50A and a second roughened portion 50B. Furthermore, the resin member 60 does not include the second flange portion 66 in the above embodiment. That is, the resin member 60 is composed of a cylindrical portion 62, a first flange portion 64, and a frame-shaped portion 68.

[0073] Here, thick portion 23 is provided at the periphery of opening 24, including at least a region SP1 that is inside position P1 of the outermost end of first roughened portion 50A. More specifically, in this first modified example, first roughened portion 50A is provided inside thick portion 23 in plan view (as viewed from axial direction A).

[0074] According to the configuration of the first modified example, the thick-walled portion 23 is provided at the periphery of the opening 24, including at least a region SP1 that is inward from the position P1 of the outermost end of the first roughened portion 50A. Therefore, when the case member 20 is welded, the heat that reaches the first roughened portion 50A from the outer periphery of the cover member 22 can be dispersed by the thick-walled portion 23. This prevents the heat from concentrating on the first roughened portion 50A, and as a result, it is possible to effectively prevent the resin member 60 in contact with the first roughened portion 50A from melting.

[0075] (Second Modification) A sealed structure 10C according to a second modified example of the embodiment will be described below with reference to Fig. 6. This second modified example basically follows the configuration of the first modified example described above. Therefore, the same components as those in the first modified example are designated by the same reference numerals and their description will be omitted.

[0076] As shown in Figure 6, in the second modified sealed structure 10C, the roughened portion 80 has a first roughened portion 80A formed on the outer surface 22B of the cover member 22 and a second roughened portion 80B formed on the inner surface 22A of the planar portion 48 of the terminal member 40.

[0077] The first roughened portion 80A has a plurality of annular portions 82 formed on the periphery of the opening 24 and arranged concentrically around the opening 24. The number of annular portions 82 is not particularly limited, but in this embodiment, the plurality of annular portions 82 are composed of an inner annular portion 82A having a circular band shape and an outer annular portion 82B having a circular band shape that covers the inner annular portion 82A from the outside. The inner annular portion 82A and the outer annular portion 82B are spaced apart in the radial direction.

[0078] Like the first roughened portion 80A, the second roughened portion 80B is formed on the periphery of the opening 24 and has a plurality of annular portions 84 (inner annular portion 84A, outer annular portion 84B) arranged concentrically around the opening 24.

[0079] Also in the second modified example, the first roughened portion 80A and the second roughened portion 80B at least partially overlap when viewed in the axial direction A of the terminal member 40. As shown in the figure, the position of the innermost end of the second roughened portion 80B (reference numeral omitted) may be located more inward than the position of the innermost end of the first roughened portion 80A (reference numeral omitted). As shown in the figure, the position of the outermost end of the second roughened portion 80B (reference numeral omitted) may be located more outward than position P1 of the outermost end of the first roughened portion 80A.

[0080] Furthermore, similar to the first modified example described above, in the second modified example, the thick portion 23 of the cover member 22 is provided at the peripheral portion of the opening 24, including at least a region SP1 that is inside the position of the outermost end P1 of the first roughened portion 80A.

[0081] As explained above, the configuration of this second modified example basically follows the configurations of the above embodiment and the above first modified example, and therefore, similar actions and effects can be obtained.

[0082] However, as mentioned above, when external vibrations are input to the terminal member via a bus bar (not shown) or the like, cracks may occur on the resin member 60 side, which has lower rigidity, in the roughened portion 80, where the bonding strength between the case member 20 and the resin member 60 is improved.

[0083] According to these two modifications, the first roughened portion 80A and the second roughened portion 80B have a plurality of annular portions 82, 84 arranged concentrically around the opening 24. Therefore, because the annular portions are spaced apart in the radial direction, even if a crack occurs in one annular portion, the crack is prevented from spreading to the other annular portions. This allows the bonding strength between the case member 20 and the resin member 60 to be maintained for a long period of time.

[0084] In the sealed structure 10A according to the above embodiment, the first roughened surface portion 50A and the second roughened surface portion 50B may be replaced by a first roughened surface portion 80A and a second roughened surface portion 80B.

[0085] (Third Modification) A sealed structure 10D according to a third modified example of the above embodiment will be described below with reference to Fig. 7. This third modified example basically follows the configuration of the second modified example described above. Therefore, the same components as those in the second modified example are designated by the same reference numerals and their description will be omitted.

[0086] 7, in a sealed structure 10D according to the third modification, a lid member 22 has a thick portion 23 provided on the periphery of an opening 24, and a thin portion 25 provided inside the thick portion 23 and set to have a thickness thinner than that of the thick portion 23. This thin portion 25 is provided by forming a step on the inner circumferential surface of the cylindrical thick portion 23.

[0087] Similar to the above embodiment, the resin member 60 is composed of a cylindrical portion 62, a first flange portion 64, a second flange portion 66, and a frame-shaped portion 68. Here, the second flange portion 66 of the resin member 60 is provided at a position overlapping with the thin-walled portion 25 in a plan view (as viewed from the axial direction A). Therefore, the thin-walled portion 25 of the cover member 22 is configured to fit between the first flange portion 64 and the second flange portion 66 of the resin member 60.

[0088] Furthermore, similar to the second modified example, the roughened portion 80 has a first roughened portion 80A formed on the outer surface 22B of the cover member 22 and a second roughened portion 80B formed on the inner surface 48A of the planar portion 48 of the terminal member 40.

[0089] The first roughened portion 80A is made up of a plurality of annular portions arranged concentrically around the opening 24 at the periphery of the opening 24. The inner annular portion 82A arranged on the innermost periphery is formed at a position overlapping the thin-walled portion 25 of the lid member 22 in a plan view (as viewed from the axial direction A). The outer annular portion 82B arranged on the outermost periphery is formed at a position overlapping the thin-walled portion 25 of the lid member 22 in a plan view (as viewed from the axial direction A). As a result, the plate thickness T1 of the lid member 22 at the location where the innermost annular portion (inner annular portion 82A) is provided is larger than that of the outermost annular portion (outer annular portion 82B). is thinner than the plate thickness T2 at the position where the

[0090] Furthermore, similar to the first and second modified examples described above, in the third modified example, the thick portion 23 of the cover member 22 is provided at the peripheral portion of the opening 24, including at least a region SP1 that is inside the position of the outermost end P1 of the first roughened portion 80A.

[0091] As explained above, the configuration of this third modified example basically follows the configurations of the above embodiment and the above first and second modified examples, and therefore can achieve the same functions and effects.

[0092] Furthermore, according to the third modification, the cover member 22 has a thickness T1 at a portion where the inner annular portion 82A is provided that is thinner than a thickness T2 at a portion where the outer annular portion 82B is provided. Therefore, even if heat generated during welding of the case member 20 reaches the outermost annular portion (outer annular portion 82B) near the welded portion and melts a portion of the resin member 60 in contact with the outermost annular portion, the innermost annular portion (inner annular portion 82A) far from the welded portion can maintain the bonding strength between the case member 20 and the resin member 60. Furthermore, because the thickness T1 at a portion where the innermost annular portion is provided is thinner than the thickness T2 at a portion where the outermost annular portion is provided, the mass of the case member 20 can be reduced. In this manner, the sealed structure 10D can reduce the weight of the component while strengthening the bonding strength between the case member 20 and the resin member 60.

[0093] Furthermore, in the third modified example, the thin portion 25 of the cover member 22 is fitted between the first flange 64 and the second flange 66 of the resin member 60. This improves the sealing performance of the opening 24 by the resin member 60. [supplementary explanation]

[0094] Although the embodiments and modifications of the present invention have been described above, the present invention is not limited to the above examples. Furthermore, the configurations of the above embodiments and modifications can be combined or substituted as appropriate within the scope of the gist of the invention. [Explanation of symbols]

[0095] 10A,10B,10C,10D Sealed structure 22 Lid member (case member) 23 Thick wall part 24 Opening 30 Electrode body 40 Terminal member 46 Shaft 48 Plane section 50A, 80A First roughened section 50B, 80B Second roughened portion 82 Multiple annular parts 82A Inner annular part (innermost annular part) 82B Outer annular portion (outermost annular portion) A axis direction P1: Position of the outermost end of the first roughened portion T1, T2 plate thickness

Claims

1. A sealed structure in which a gap between a case member in which an electrode body is housed and a terminal member drawn out through an opening of the case member is sealed by an integrally molded resin member, the case member has a first roughened portion that roughens the surface to improve bonding strength with the resin member, and the first roughened portion is formed on at least a part of the periphery of the opening; Closed structure.

2. The terminal member is a shaft portion passed through the opening; a flat surface portion provided on one end side of the shaft portion in the axial direction and disposed outside the case member, the planar portion has a second roughened portion whose surface is roughened to improve bonding strength with the resin member, and the second roughened portion at least partially overlaps with the first roughened portion when viewed in the axial direction of the shaft portion; The sealed structure according to claim 1 .

3. The first roughened portion has a plurality of annular portions arranged concentrically around the opening at the periphery of the opening. The sealed structure according to claim 1 or 2.

4. A thick-walled portion having the thickest plate thickness in the case member is provided at a peripheral edge of the opening, and the thick-walled portion is provided at least in a region of the peripheral edge that is more inward than the position of an outermost end of the first roughened portion. The sealed structure according to claim 1 or 2.

5. the first roughened portion has a plurality of annular portions arranged concentrically around the opening at a periphery of the opening, The case member has a thickness smaller at a portion where the annular portion on the innermost periphery is provided than at a portion where the annular portion on the outermost periphery is provided. The sealed structure according to claim 1 or 2.

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