Metal-resin composite and method for producing the metal-resin composite

Abstract

To provide: a metal member excellent in sealability; a method for manufacturing the metal member; a metal resin composite excellent in sealability; and a method for manufacturing the metal resin composite.SOLUTION: A resin member (a lid member 30 and a positive electrode terminal member 50) connected with a resin member (a positive electrode resin member 70) has a connection area (connection areas E1-E4) sealing between first and second spaces (the outside and inside of a battery 1) on the surface. The connection area includes a roughened area (roughened areas F1-F4) including a basic layer (basic layers 35 and 55) formed on the surface and formed by depositing debris particles and a pillar group layer (columnar group layers 36 and 56) including nano columnar bodies (nano columnar bodies 361 and 561) tying debris particles in a row from the basic layer to be extended in the height direction and two-dimensionally stood close together; and the average height of the nano columnar bodies in the roughened area is 84 nm or more.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] The technical field disclosed in this specification is ,gold genus resin composite Body The present invention also relates to a method for producing a metal-resin composite. [Background technology]

[0002] Metal-resin composites in which a metal member and a resin member are bonded together are known. In order to improve the sealing properties between the metal member and the resin member, the surface of the metal member is roughened in advance using, for example, a laser. Patent Document 1, for example, is an example of related prior art.

[0003] Patent Document 1 describes the formation of nano-recesses having an opening width L and depth D on the submicron or nano-order on the surface of a metal member. Specifically, the nano-recesses are formed so that the relationship between the opening width L and the depth D satisfies D / L≧1. In other words, protruding portions that cannot be described as columnar portions are formed on the surface of the metal member as a whole. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-75805 Summary of the Invention [Problem to be solved by the invention]

[0005] However, conventional metal members do not provide sufficient sealing performance at the joint when joined to a resin member, and there is a demand for further improvement in sealing performance.

[0006] The present invention has been made in view of the above circumstances, and its objective is to , Shi The present invention provides a metal-resin composite body having excellent sealing properties and a method for producing the metal-resin composite body. [Means for solving the problem]

[0007] The metal member made for the purpose of solving the above-mentioned problems has a bonding area on the surface to which the resin member is bonded and which seals the gap between the first space and the second space together with the resin member. death a metal member in which the bonding region includes a base layer formed on the surface and in which debris particles are deposited, and a column group layer in which the debris particles are linked together in a string-like pattern from the base layer to form nanocolumns that stand two-dimensionally in a vertical direction, and the average height of the nanocolumns in the roughened region is 84 nm or more. and a resin member bonded to the bonding region, wherein the resin forming the resin member reaches the base layer and fills the gaps between the nanocolumnar bodies. is.

[0008] The present invention metal resin composite According to the publication, a metal member includes a roughened region in a bonding region with a resin member, in which a base layer formed by the accumulation of debris particles and a column group layer in which the debris particles are linked to the base layer in a string-like pattern and nanocolumns extending in the height direction are two-dimensionally arranged, and the average height of the nanocolumns in the roughened region is 84 nm. and a resin member bonded to the bonding region, wherein the resin forming the resin member reaches the base layer and fills the gaps between the nanocolumnar bodies. So , contact This can improve the sealing performance of the joint portion. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a perspective view of a battery according to an embodiment. [Figure 2] 2 is a cross-sectional view taken along the line AA in FIG. 1. [Figure 3] FIG. 2 is a perspective view of a positive electrode terminal member. [Figure 4] FIG. 2 is a perspective view of a unit member extracted from the battery of FIG. 1. [Figure 5] 4A is a cross-sectional view taken along line BB in FIG. 4, and FIG. 4B is a cross-sectional view taken along line CC in FIG. [Figure 6] (A) is an explanatory diagram illustrating the bonding area between the upper surface of the lid member and the positive electrode resin member, and the area on the upper surface of the lid member that has been roughened, and (B) is an explanatory diagram illustrating the bonding area between the lower surface of the lid member and the positive electrode resin member, and the area on the lower surface of the lid member that has been roughened. [Figure 7]FIG. 1A is an explanatory diagram illustrating the joint area between a part of the side surface of the positive electrode terminal member and the positive electrode resin member, and the area on the part of the side surface of the positive electrode terminal member that has been roughened; and FIG. 1B is an explanatory diagram illustrating the joint area between the underside of the long straight portion of the positive electrode terminal member and the positive electrode resin member, and the area on the underside of the long straight portion of the positive electrode terminal member that has been roughened. [Figure 8] This is an image showing the actual formation of the foundation layer and pillar group layer. [Figure 9] This is an image showing how the resin (polyphenylene sulfide) of the positive electrode resin member actually fills the gaps between the nanocolumnar bodies. [Figure 10] 3 is a flowchart of a method for manufacturing a battery according to an embodiment. [Figure 11] 1A is a diagram schematically illustrating the roughening treatment for the roughened region on the lower surface of the lid, and FIG. 1B is a diagram schematically illustrating the roughening treatment for the roughened region on the side surface of the terminal. [Figure 12] 1A to 1C are diagrams illustrating a schematic diagram of an insert molding process. [Figure 13] FIG. 2 is an explanatory diagram schematically illustrating a test specimen. [Figure 14] 10 is a table showing the relationship between various conditions for pulsed laser irradiation performed on a roughened region and the average height and surface area ratio of nanocolumns formed in the roughened region. [Figure 15] (A) is a scatter plot in which the horizontal axis represents the average height of the nanocolumns and the vertical axis represents the amount of helium leak. (B) is a scatter plot in which the horizontal axis represents the surface area ratio and the vertical axis represents the amount of helium leak. [Figure 16] (A) is an example of a cross-sectional image of a cross-sectional sample obtained using a scanning electron microscope, and (B) is an explanatory diagram explaining the cross-sectional area and base length of a nanocolumn based on Figure 16(A). DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The battery 1 constituting the metal-resin composite of the present invention is an example of an electricity storage device, specifically, a rectangular, sealed lithium-ion secondary battery installed in vehicles such as hybrid cars, plug-in hybrid cars, and electric cars. In the following, the symbols X, Y, and Z indicating directions in the drawings represent left-right, front-rear, and up-down directions. Furthermore, the symbols U, D, L, R, F, and B at the end of the arrows indicating each direction represent upper, lower, left, right, front, and rear directions. However, these directions and positions are specified for convenience of explanation. Therefore, the orientation in which the battery 1 is installed is not limited in any way.

[0011] [Battery configuration] Fig. 1 is a perspective view of a battery 1. Fig. 2 is a cross-sectional view taken along line AA in Fig. 1. As shown in Figs. 1 and 2, the battery 1 has a case 10 that seals the interior, an electrode assembly 40 housed in the case 10, an electrolyte 3, an insulating holder 5, and a positive electrode terminal member 50 and a negative electrode terminal member 60 connected to the electrode assembly 40.

[0012] Case 10 has an overall flat, bottomed rectangular parallelepiped shape. In this embodiment, case 10 is made of aluminum. However, the material of case 10 is not limited to aluminum, but is preferably made of metal. For example, case 10 may be made of other metals such as aluminum alloys, iron, and iron alloys. Case 10 is also made of a main body member 20 and a cover member 30.

[0013] The main body member 20 has a rectangular cylindrical shape with a bottom. The main body member 20 also has an opening 21. In other words, the main body member 20 has a rectangular plate-shaped bottom 12, a pair of front and rear portions 13 and 14 extending perpendicularly from the edges of the front side F and the rear side B of the bottom 12, and a pair of left and right portions 15 and 16 extending perpendicularly from the end of the left side L and the end of the right side R of the bottom 12. The opening 21 has a rectangular shape with its long side extending in the left-right direction X and its short side extending in the front-to-back direction Y. The bottom 12 has a rectangular plate-like shape with its long side extending in the left-to-right direction X and its short side extending in the front-to-back direction Y. The front and rear portions 13 and 14 have rectangular plate-like shapes with their long side extending in the left-to-right direction X and their short side extending in the up-to-down direction Z. The left and right portions 15 and 16 have rectangular plate-like shapes with their long side extending in the up-to-down direction Z and their short side extending in the front-to-back direction Y.

[0014] The height (length in the vertical direction Z) of the front portion 13 and the rear portion 14 is the same as the height (length in the vertical direction Z) of the left portion 15 and the right portion 16. Furthermore, the height (length in the vertical direction Z) of the front portion 13, etc., and the length in the horizontal direction X of the front portion 13 and the rear portion 14 are significantly longer than the length in the vertical direction Y of the left portion 15 and the right portion 16. Therefore, hereinafter, with regard to the case 10, the main body member 20, and the cover member 30, the horizontal direction X may be referred to as the "length direction," the vertical direction Y as the "width direction," and the vertical direction as the "height direction."

[0015] The lid member 30 closes the opening 21 of the main body member 20. More specifically, the peripheral edge of the lid member 30 is laser welded along the entire periphery to the tip ends of the upper sides U of the front side portion 13, rear side portion 14, left side portion 15, and right side portion 16. At the boundary between the tip end of the main body member 20 and the peripheral edge of the lid member 30, a melted and solidified portion 18 is formed along the entire periphery, where the main body member 20 and the lid member 30 are melted and solidified by the laser.

[0016] A safety valve 19 is provided on the lid member 30 slightly to the left L of the center in the left-right direction X. The safety valve 19 ruptures and opens when the internal pressure of the case 10 exceeds a valve opening pressure. A liquid inlet hole 30k that penetrates the lid member 30 in the up-down direction Z is formed on the lid member 30 slightly to the right R of the center in the left-right direction X. An aluminum sealing member 39 is fitted into the liquid inlet hole 30k from an upper side U, thereby airtightly sealing the liquid inlet hole 30k.

[0017] A positive electrode insertion hole 33h penetrating the lid member 30 in the up-down direction Z is formed near an end of the lid member 30 on one side in the left-right direction X (left side L in FIGS. 1 and 2). A negative electrode insertion hole 34h penetrating the lid member 30 in the up-down direction Z is formed near an end of the lid member 30 on the other side in the left-right direction X (right side R in FIGS. 1 and 2). The positive electrode insertion hole 33h and the negative electrode insertion hole 34h are formed in a rectangular shape with the long side extending in the left-right direction X and the short side extending in the front-rear direction Y. A generally vertically elongated positive electrode terminal member 50 (extending in one direction) is inserted into the positive electrode insertion hole 33h from the upper side U along its length. A generally vertically elongated negative electrode terminal member 60 (extending in one direction) is inserted into the negative electrode insertion hole 34h from the upper side U along its length.

[0018] The positive electrode terminal member 50 is fixed to the lid member 30 in a state insulated from the lid member 30 via the positive electrode resin member 70. Therefore, the positive electrode terminal member 50 is supported by the lid member 30 via the positive electrode resin member 70. In this embodiment, the positive electrode terminal member 50 is made of aluminum. However, the material of the positive electrode terminal member 50 can be appropriately selected as long as it can be electrically connected to the positive electrode current collecting portion 41r of the electrode body 40, which will be described later.

[0019] The negative electrode terminal member 60 is fixed to the lid member 30 in a state insulated from the lid member 30 via the negative electrode resin member 80. Therefore, the negative electrode terminal member 60 is supported by the lid member 30 via the negative electrode resin member 80. In this embodiment, the negative electrode terminal member 60 is made of copper. However, the material of the negative electrode terminal member 60 can be appropriately selected as long as it can be electrically connected to the negative electrode current collecting part 42r of the electrode body 40, which will be described later.

[0020] The electrode body 40 is a so-called "wound-type" electrode body. In the electrode body 40, a strip-shaped positive electrode plate 41 and a strip-shaped negative electrode plate 42 are wound in a predetermined winding direction with a strip-shaped separator 43 sandwiched therebetween. As a result, the electrode body 40 is formed in an overall flat shape with horizontally elongated rectangular side surfaces extending in the up-down direction Z and the left-right direction X on the front side F and the rear side B.

[0021] The positive electrode plate 41 has a positive electrode current collector foil (not shown) and a positive electrode active material layer (not shown) supported on the current collector foil. The positive electrode current collector foil is made of aluminum. However, the material of the positive electrode current collector foil can be appropriately selected within a range that allows it to function as a positive electrode of a lithium-ion secondary battery. On the other hand, the negative electrode plate 42 has a negative electrode current collector foil (not shown) and a negative electrode active material layer (not shown) supported on the current collector foil. The negative electrode current collector foil is made of copper. However, the material of the negative electrode current collector foil can be appropriately selected within a range that allows it to function as a negative electrode of a lithium-ion secondary battery.

[0022] The electrode body 40 also has a positive electrode current collector 41r formed thereon. The positive electrode current collector 41r is a portion where the positive electrode current collector foil is exposed. A positive electrode terminal lower portion 52 of the positive electrode terminal member 50 is bonded to the positive electrode current collector 41r. Similarly, the electrode body 40 also has a negative electrode current collector 42r formed thereon. The negative electrode current collector 42r is a portion where the negative electrode current collector foil is exposed. A negative electrode terminal lower portion 62 of the negative electrode terminal member 60 is bonded to the negative electrode current collector 42r. Therefore, the electrode body 40 is supported by the cover member 30 via the positive electrode terminal member 50 and the negative electrode terminal member 60.

[0023] Although detailed illustration is omitted, the positive electrode current collecting portion 41r is a portion that protrudes beyond the negative electrode plate 42 and separator 43 in the axial direction of the electrode body 40 and is wound with only the positive electrode current collecting foil. Similarly, the negative electrode current collecting portion 42r is a portion that protrudes beyond the positive electrode plate 41 and separator 43 in the axial direction of the electrode body 40 and is wound with only the negative electrode current collecting foil. In this embodiment, the positive electrode current collecting portion 41r is formed at the end of the left side L of the electrode body 40. The negative electrode current collecting portion 42r is formed at the end of the right side R of the electrode body 40.

[0024] The electrode assembly 40 is spaced a certain distance from the bottom 12, front 13, rear 14, left 15, and right 16 of the main body member 20, as well as the cover member 30. An insulating holder 5 is disposed between the electrode assembly 40 and the main body member 20 to reliably maintain insulation. The shape and material of the insulating holder 5 can be appropriately determined as long as it can be disposed between the electrode assembly 40 and the main body member 20 and can insulate the electrode assembly 40 from the main body member 20. In this embodiment, the insulating holder 5 is made of a strip-shaped film of polypropylene (PP), a synthetic resin. The insulating holder 5 is formed in a bag shape. The bag-shaped insulating holder 5 encases the electrode assembly 40 with the upper side U open. That is, the insulating holder 5 insulates the inner surfaces of the bottom 12, front side 13, rear side 14, left side 15 and right side 16 of the main body member 20 from the outer surface of the electrode body 40 facing the main body member 20.

[0025] The positive electrode resin member 70 is made of a thermoplastic resin, specifically polyphenylene sulfide (PPS). The positive electrode resin member 70 is bonded to the lid member 30 and the positive electrode terminal member 50. The lid member 30, the positive electrode terminal member 50, and the positive electrode resin member 70 are integrated by bonding the positive electrode resin member 70 to the lid member 30 and the positive electrode terminal member 50, and the battery 1 including this integrated assembly constitutes a composite of metal and resin. The positive electrode resin member 70 also provides insulation between the lid member 30 and the positive electrode terminal member 50 while hermetically sealing them. That is, the positive electrode resin member 70 functions as an insulating member and a sealing member between the lid member 30 and the positive electrode terminal member 50. The material of the positive electrode resin member 70 can be appropriately selected as long as it can hermetically seal the lid member 30 and the positive electrode terminal member 50 while insulating them from each other, and can also be other types of resin such as other types of thermoplastic resins or thermosetting resins.

[0026] The negative electrode resin member 80 is made of a thermoplastic resin, specifically polyphenylene sulfide (PPS). The negative electrode resin member 80 is bonded to the lid member 30 and the negative electrode terminal member 60. The lid member 30, the negative electrode terminal member 60, and the negative electrode resin member 80 are integrated by bonding the negative electrode resin member 80 to the lid member 30 and the negative electrode terminal member 60, and the battery 1 including this integrated member constitutes a composite of metal and resin. The negative electrode resin member 80 also provides insulation between the lid member 30 and the negative electrode terminal member 60 and hermetically seals them. That is, the negative electrode resin member 80 functions as an insulating member and a sealing member between the lid member 30 and the negative electrode terminal member 60. The material of the negative electrode resin member 80 can be appropriately selected as long as it can hermetically seal the lid member 30 and the negative electrode terminal member 60 while insulating them from each other, and can also be other types of resin such as other types of thermoplastic resins or thermosetting resins.

[0027] Next, the shape of the positive electrode terminal member 50 will be described. Fig. 3 is a perspective view of the positive electrode terminal member 50. As shown in Fig. 3, the positive electrode terminal member 50 has a positive electrode terminal upper portion 51, a positive electrode terminal lower portion 52, and a positive electrode terminal intermediate portion 53. In the battery 1, the positive electrode terminal upper portion 51 is disposed on the upper side U relative to the battery 1. The positive electrode terminal lower portion 52 is disposed on the lower side D relative to the battery 1.

[0028] The positive terminal upper portion 51 has a constant L-shaped cross section in one direction. In detail, one straight portion of the L-shaped cross section of the positive terminal upper portion 51 is longer than the other straight portion. Therefore, the rectangular plate-shaped portion of the positive terminal upper portion 51 that corresponds to the longer straight portion of the L-shaped cross section is referred to as the "long straight portion 51a," and the portion extending perpendicularly from one edge of the long straight portion 51a is referred to as the "short straight portion 51b."

[0029] In the following description of the positive electrode terminal member 50, for convenience, the symbols O, P, and Q shown in FIG. 3 are used to identify directions. The symbols O, P, and Q represent the "direction in which the L-shaped cross-sectional shape of the positive electrode terminal upper portion 51 extends at a constant angle," the "direction along the long straight portion 51a of the L-shaped cross-sectional shape of the positive electrode terminal upper portion 51," and the "direction along the short straight portion 51b of the L-shaped cross-sectional shape of the positive electrode terminal upper portion 51," respectively. In the following description of the positive electrode terminal member 50, the side in the third direction Q where the positive electrode terminal upper portion 51 is located may be referred to as the "upper side," and the side in the third direction Q where the positive electrode terminal lower portion 52 is located may be referred to as the "lower side."

[0030] The positive terminal lower portion 52 is formed perpendicular to the long straight portion 51a as a whole. The positive terminal lower portion 52 is shaped like a rectangular plate with its long side extending in the third direction Q and its short side extending in the second direction P. In addition, in the first direction O, a portion of the positive terminal lower portion 52 is contained within the positive terminal upper portion 51, while another portion protrudes outside the positive terminal upper portion 51. In addition, in the second direction P, a portion of the positive terminal lower portion 52 is contained within the positive terminal upper portion 51, while another portion protrudes outside the positive terminal upper portion 51.

[0031] The positive terminal intermediate portion 53 has an overall crank shape and connects the positive terminal upper portion 51 and the positive terminal lower portion 52. When viewed from the second direction P, the positive terminal intermediate portion 53 has a rectangular shape with its longer side in the first direction O and its shorter side in the third direction. The length of the positive terminal intermediate portion 53 in the first direction O is longer than the length of the positive terminal lower portion 52 in the first direction O. The side surface of the positive terminal lower portion 52 that protrudes outside the positive terminal upper portion 51 in the first direction O is continuous with the side surface of the positive terminal intermediate portion 53 on the same side in the first direction O.

[0032] Furthermore, both surfaces of the positive terminal intermediate portion 53 that are perpendicular to the second direction P near the connection to the short straight portion 51b are formed on the same plane as both surfaces of the short straight portion 51b that are perpendicular to the second direction P. Hereinafter, the portion of the positive terminal intermediate portion 53 that is formed on the same plane as both surfaces of the short straight portion 51b that are perpendicular to the second direction P will be referred to as the "upper connection portion 53a." The surface of the positive terminal upper portion 51, including the short straight portion 51b, on the side where the positive terminal lower portion 52 is located in the second direction P is flush with the surface of the upper connection portion 53a on the same side. Furthermore, a bent portion 53b that is bent in a crank shape toward the outside of the positive terminal upper portion 51 along the second direction P is formed on the side of the upper connection portion 53a opposite the short straight portion 51b in the third direction Q.

[0033] In this embodiment, the shape of the negative electrode terminal member 60 is the same as the shape of the positive electrode terminal member 50. Therefore, although a description using a perspective view of the negative electrode terminal member 60 will be omitted, the negative electrode terminal member 60, like the positive electrode terminal member 50, has a negative electrode terminal upper portion 61, a negative electrode terminal lower portion 62, and a negative electrode terminal intermediate portion 63 that correspond to the positive electrode terminal upper portion 51, the positive electrode terminal lower portion 52, and the positive electrode terminal intermediate portion 53.

[0034] Next, the bonding structure between the positive electrode resin member 70 and the lid member 30 and the positive electrode terminal member 50, as well as the roughening treatment of the lid member 30 and the positive electrode terminal member 50, will be described. FIG. 4 is a perspective view of a unit member 1A that constitutes a part of the battery 1 shown in FIGS. 1 and 2 and is composed of the integrated lid member 30, the positive electrode terminal member 50, the positive electrode resin member 70, and the negative electrode terminal member 60 and the negative electrode resin member 80. FIG. 5(A) is a cross-sectional view taken along line BB in FIG. 4, and FIG. 5(B) is a cross-sectional view taken along line CC in FIG. 4. FIG. 6 is an explanatory diagram illustrating the bonding region between the lid member 30 and the positive electrode resin member 70 and the roughened region of the lid member 30. FIG. 7 is an explanatory diagram illustrating the bonding region between the positive electrode terminal member 50 and the positive electrode resin member 70 and the roughened region of the positive electrode terminal member 50.

[0035] The positive electrode terminal member 50 is fixed to the lid member 30 via the positive electrode resin member 70 with the first direction O parallel to the left-right direction X and the positive electrode terminal lower portion 52 located on the rear side B. On the other hand, the negative electrode terminal member 60 is fixed to the lid member 30 via the negative electrode resin member 80 with the first direction O parallel to the left-right direction X and the negative electrode terminal lower portion 62 located on the front side F.

[0036] The upper surface of the long straight portion 51a is exposed to the upper side U. In addition, the upper surface of the lid member 30 and the lower surface of the long straight portion 51a are located at approximately the same position in the vertical direction Z. Furthermore, the lower surface of the short straight portion 51b is located slightly lower than the lower surface of the lid member 30 in the vertical direction Z. In a plan view (looking from the upper side U toward the lower side D), the long straight portion 51a of the positive electrode terminal member 50 inserted into the positive electrode insertion hole 33h is completely contained within the positive electrode insertion hole 33h. In addition, in the left-right direction X and the front-back direction Y, the long straight portion 51a is located at approximately the center of the positive electrode insertion hole 33h.

[0037] The positive electrode resin member 70 is formed in the vertical direction Z from the upper end of the positive electrode terminal upper portion 51 to a position U slightly above the lower end of the upper connection portion 53a. The positive electrode resin member 70 hermetically seals the gap between the lid member 30 and the positive electrode terminal member 50. As will be described later, in this embodiment, the positive electrode resin member 70 is integrally formed by insert molding. For convenience, however, the portion of the positive electrode resin member 70 above the upper surface of the lid member 30 will be referred to as the "positive electrode resin upper portion 71," the portion below the lower surface of the lid member 30 will be referred to as the "positive electrode resin lower portion 72," and the portion between the upper and lower surfaces of the lid member 30, in other words, the portion filled in the positive electrode insertion hole 33h, will be referred to as the "positive electrode resin middle portion 73."

[0038] The positive electrode resin upper portion 71 has a positive electrode resin upper frame portion 71a that surrounds the entire periphery of the long straight portion 51a, and a positive electrode resin upper protrusion portion 71b that is connected to the positive electrode resin upper frame portion 71a.

[0039] The positive electrode resin upper frame portion 71a is formed in a rectangular frame shape. A first width W1, which is the distance from the inner edge to the outer edge of each straight portion of the positive electrode resin upper frame portion 71a, is substantially the same. The positive electrode resin upper protrusion 71b is formed to protrude toward the right side R from a partial range approximately in the center of the straight portion formed on the right side R of the positive electrode resin upper frame portion 71a. The positive electrode resin upper protrusion 71b has a rectangular plate shape with its long side direction in the left-right direction X and its short side direction in the front-rear direction Y. The lengths of the positive electrode resin upper protrusion 71b in the left-right direction X and the front-rear direction Y are longer than the first width W1. The positive electrode resin upper protrusion 71b is a location where a gate member GT (see FIG. 12) into which molten resin is injected during insert molding is placed.

[0040] The positive electrode resin upper frame portion 71a is bonded to the entire outer surface of the long straight portion 51a and to a rectangular annular lid upper surface frame bonding region E11 that surrounds the entire edge of the positive electrode insertion hole 33h on the top surface of the lid member 30. A second width W2, which is the distance from the inner edge to the outer edge of each straight portion of the lid upper surface frame bonding region E11, is substantially uniform. The positive electrode resin upper protrusion 71b is bonded to the top surface of the lid member 30 over the entire bottom surface.

[0041] In the following, the region on the top surface of the lid member 30 that is bonded to the positive electrode resin upper protrusion 71b will be referred to as the "lid top surface rectangular bonding region E12." The lid top surface rectangular bonding region E12 is formed to protrude toward the right side R from a partial range approximately in the center of the straight portion on the right side R of the lid top surface frame-shaped bonding region E11. In other words, the lid top surface frame-shaped bonding region E11 and the lid top surface rectangular bonding region E12 are connected and form a bonding region with the positive electrode resin member 70 on the top surface of the lid member 30. Therefore, the lid top surface frame-shaped bonding region E11 and the lid top surface rectangular bonding region E12 will be collectively referred to as the "lid top surface bonding region E1."

[0042] The positive electrode resin lower portion 72 is generally formed in the shape of a rectangular plate with its long sides extending in the left-right direction X and its short sides extending in the front-rear direction Y. The overlapping portion of the positive electrode terminal member 50 in the up-down direction Z is completely embedded inside the positive electrode resin lower portion 72. Therefore, the positive electrode resin lower portion 72 is joined to the entire outer surface of the overlapping portion of the short straight portion 51b and the upper connection portion 53a of the positive electrode terminal member 50 in the up-down direction Z.

[0043] The positive electrode resin lower portion 72 is joined to a rectangular annular lid underside joining region E2 that completely surrounds the edge of the positive electrode insertion hole 33h on the underside of the lid member 30. The distances from the inner edge to the outer edge of each straight line portion of the lid underside joining region E2 are substantially the same on the front side F and the rear side B and are substantially the same on the left side L and the right side R. A fourth width W4, which is the distance from the inner edge to the outer edge of the straight line portion on the left side L and the right side R, is wider than a third width W3, which is the distance from the inner edge to the outer edge of the straight line portion on the front side F and the rear side B.

[0044] The positive electrode resin intermediate portion 73 is connected to the positive electrode resin upper portion 71 and the positive electrode resin lower portion 72. The positive electrode resin intermediate portion 73 also fills the positive electrode insertion hole 33h. Therefore, the positive electrode resin intermediate portion 73 is bonded to the inner surface of the positive electrode insertion hole 33h of the lid member 30 around the entire periphery. Furthermore, the portion of the short straight portion 51b of the positive electrode terminal member 50 that overlaps with it in the up-down direction Z is completely embedded inside the positive electrode resin intermediate portion 73. Therefore, the positive electrode resin intermediate portion 73 is bonded to the entire outer surface of the portion of the short straight portion 51b of the positive electrode terminal member 50 that overlaps with it in the up-down direction Z.

[0045] The entire outer surface of the long straight portion 51a of the positive terminal member 50 is joined to the positive resin upper frame portion 71a. The entire outer surface of the short straight portion 51b of the positive terminal member 50, which overlaps with the positive resin intermediate portion 73 and the positive resin lower portion 72 in the vertical direction Z, is joined to the positive resin intermediate portion 73 and the positive resin lower portion 72. The entire outer surface of the upper connection portion 53a of the positive terminal member 50, which overlaps with the positive resin lower portion 72 in the vertical direction Z, is joined to the positive resin intermediate portion 73 and the positive resin lower portion 72. Therefore, the region of the side surface of the positive terminal member 50 that is flush with the positive terminal upper portion 51 and the upper connection portion 53a and that is joined to the positive electrode resin member 70 is referred to as the "terminal side surface joining region E3." In addition, the area that is joined to the positive electrode resin member 70, which is the entire lower surface of the long straight portion 51a on the side where the positive electrode terminal lower portion 52 is formed in the third direction Q of the positive electrode terminal member 50, is referred to as the ``terminal lower surface joining area E4.''

[0046] As described above, the lid member 30 and the positive electrode terminal member 50 have a plurality of bonding regions with the positive electrode resin member 70. Specific regions of the lid member 30 and the positive electrode terminal member 50, including the bonding regions with the positive electrode resin member 70, are subjected to a roughening treatment by pulsed laser irradiation in order to improve sealing performance. This roughening treatment will now be described.

[0047] The roughening treatment is applied to a roughened lid upper surface region F1 that completely surrounds and accommodates the lid upper surface joining region E1 on the upper surface of the lid member 30, and a roughened lid lower surface region F2 that completely surrounds and accommodates the lid lower surface joining region E2 on the lower surface of the lid member 30. In addition, the roughening treatment is applied to a roughened terminal side surface region F3 that completely surrounds and accommodates the terminal side surface joining region E3 on the entire side surface that is flush across the positive terminal upper portion 51 and the upper connection portion 53a of the positive terminal member 50, and to a roughened terminal lower surface region F4 that is the terminal lower surface joining region E4 itself.

[0048] Although detailed conditions will be described later, the roughening treatment of the roughened lid upper surface region F1, the roughened lid lower surface region F2, the roughened terminal side surface region F3, and the roughened terminal lower surface region F4 is performed by pulsed laser irradiation. The roughened lid upper surface region F1 and the roughened lid lower surface region F2 are layered with a base layer 35 formed by a planar accumulation of debris particles and a column layer 36 formed by a two-dimensional forest of numerous nanocolumns 361 formed by debris particles linked together in a string-like pattern and extending in the vertical direction. Similarly, the roughened terminal side surface region F3 and the roughened terminal lower surface region F4 are layered with a base layer 55 formed by a planar accumulation of debris particles and a column layer 56 formed by a two-dimensional forest of numerous nanocolumns 561 formed by debris particles linked together in a string-like pattern and extending in the vertical direction. That is, the lid upper surface bonding area E1 and the lid lower surface bonding area E2, to which the positive electrode resin member 70 is bonded and which, together with the positive electrode resin member 70, seal the space between the outside and inside of the battery 1, include a base layer 35 formed by a planar accumulation of debris particles on the surface of the lid member 30, and a column group layer 36 formed by debris particles linked to the base layer 35 in a string-like pattern, resulting in a two-dimensional forest of nanocolumns 361 extending in the vertical direction. Similarly, the terminal side surface bonding area E3 and the terminal undersurface bonding area E4, which are bonded to the positive electrode resin member 70 and seal the space between the outside and inside of the battery 1 together with the positive electrode resin member 70, include a terminal side surface roughened area F3 and a terminal undersurface roughened area F4, which are formed by a basic layer 55 formed by a planar accumulation of debris particles on the surface of the positive electrode terminal member 50, and a column group layer 56 formed by a two-dimensional forest of nanocolumns 561 extending in the height direction, formed by debris particles linked to the basic layer 55 in a string-like pattern.

[0049] Debris particles are particles with a diameter of 100 nm or less that are formed when a pulsed laser is irradiated onto the surface of a metal component, explosively vaporizing part of the surface, and then condense compounds formed when metal vapor or metal atoms react with atmospheric gases. These particles then fall onto the surface near the laser irradiation position.

[0050] The average height of the numerous nanocolumnar structures 361 standing in a forest of column layers 36 in each of the roughened lid upper surface region F1 and the roughened lid lower surface region F2, and the average height of the numerous nanocolumnar structures 561 standing in a forest of column layers 56 in each of the roughened terminal side surface region F3 and the roughened terminal lower surface region F4, are 84 nm or more and less than 1000 nm.

[0051] The average surface area ratio of each of the roughened lid upper surface region F1, the roughened lid lower surface region F2, the roughened terminal side surface region F3, and the roughened terminal lower surface region F4 is 12.9 or greater. Note that the surface area ratio here refers to the value obtained by dividing the geometric surface area of ​​each of the roughened regions F1 to F4 by the true surface area (true surface area) that takes into account the irregularities, including the nanocolumns 361 and 561, of each of the roughened regions F1 to F4.

[0052] FIG. 8 shows an image illustrating the state in which a metal member (lid member 30, positive electrode terminal member 50) is actually roughened by pulsed laser irradiation, resulting in the formation of a base layer (base layer 35, 55) and a pillar layer (pillar layer 36, 56). As shown in FIG. 8, a base layer (base layer 35, 55) formed by the accumulation of debris particles is laminated on the surface of the metal member (lid member 30, positive electrode terminal member 50). Furthermore, a pillar layer (pillar layer 36, 56) is laminated on the base layer (base layer 35, 55) in which numerous nanocolumns (nanocolumns 361, 561) formed by debris particles linked together in a string-like pattern and extending in the height direction are two-dimensionally forested. Note that one interval of the scale in the lower right corner of the image in FIG. 8 represents 30 nm.

[0053] In the battery 1, the resin (polyphenylene sulfide) of the positive electrode resin member 70 fills the gaps between the nanocolumns 361, 561, reaching the base layers 35, 55. In other words, the positive electrode resin member 70 is bonded to the surfaces of the nanocolumns 361, 561 and the surfaces of the base layers 35, 55. FIG. 9 shows an image illustrating how the resin (polyphenylene sulfide) of the positive electrode resin member 70 actually fills the gaps between the numerous nanocolumns (nanocolumns 361, 561). Note that one scale interval in the lower right corner of the image on the left side of FIG. 9 represents 10 μm, and one scale interval in the lower right corner of the image on the right side of FIG. 9 represents 15 nm.

[0054] The joining structure between the negative electrode resin member 80 and the lid member 30 and the negative electrode terminal member 60 is configured similarly to the joining structure between the positive electrode resin member 70 and the lid member 30 and the positive electrode terminal member 50 described above with reference to Figures 5 to 9. The roughening treatment of the joining region of the lid member 30 with the negative electrode resin member 80 and the joining region of the negative electrode terminal member 60 with the negative electrode resin member 80 is configured similarly to the roughening treatment of the lid member 30 and the positive electrode terminal member 50 described above with reference to Figures 5 to 9.

[0055] [Battery manufacturing] Next, a manufacturing method of the battery 1 will be described with reference to the flowchart in Fig. 10. The manufacturing method of the battery 1 includes a member preparation step S1, a laser irradiation step S2, an insert molding step S3, a lid assembly completion step S4, a closing step S5, a welding step S6, a liquid injection and sealing step S7, and an initial charging and aging step S8.

[0056] In the member preparation step S1, a lid member 30, a positive electrode terminal member 50, and a negative electrode terminal member 60 are prepared. Specifically, the lid member 30 is obtained by forming a liquid injection hole 30k, a positive electrode insertion hole 33h, a negative electrode insertion hole 34h, and a safety valve 19 in an aluminum plate using a conventional general processing method. Furthermore, a positive electrode terminal member 50 having the shape shown in FIG. 3 is obtained from the aluminum plate using a conventional general processing method. Furthermore, a negative electrode terminal member 60 having the same shape as the positive electrode terminal member 50 is obtained from a copper plate using a conventional general processing method.

[0057] Following the member preparation step S1, a laser irradiation step S2 is performed. In the laser irradiation step S2, a roughening treatment is performed by pulsed laser irradiation on the surface of the lid member 30, which will become the roughened lid upper surface region F1 and the roughened lid lower surface region F2 when the base layer 35 and the column layer 36 are not yet formed. This causes debris particles derived from the lid member 30 to deposit and grow into numerous nanocolumns 361, forming the roughened lid upper surface region F1 and the roughened lid lower surface region F2. Similarly, in the laser irradiation step S2, a roughening treatment is performed by pulsed laser irradiation on the surface of the positive electrode terminal member 50, which will become the roughened terminal side surface region F3 and the roughened terminal lower surface region F4 when the base layer 55 and the column layer 56 are not yet formed. This causes debris particles derived from the positive electrode terminal member 50 to deposit and grow into numerous nanocolumns 561, forming the roughened terminal side surface region F3 and the roughened terminal lower surface region F4.

[0058] As an example of various conditions for pulsed laser irradiation in the laser irradiation step S2, the energy density of one pulse of laser irradiation is 24 J / cm in the case of aluminum. 2 , and 32 J / cm for copper. 2 For example, for aluminum, the wavelength is set to 1060 nm, the average power to 25 W, the pulse period to 40 μs, the pulse width to 50 ns, the spot diameter to 63 μm, the feed rate to 1450 mm / s, and the line pitch to 0.059 mm. Figure 11 is a schematic diagram showing the trajectory of pulse laser irradiation when pulse laser is irradiated onto the lid undersurface roughened region F2 and the terminal side surface roughened region F3 in the laser irradiation step S2.

[0059] As shown in FIG. 11A, the roughened lid undersurface region F2 is irradiated with a pulsed laser beam from the leading end (the side marked "start point" in FIG. 11A) of one side of the roughened lid undersurface region F2 along the left-right direction X (the left side L in FIG. 11A) to one side in the front-rear direction Y (the rear side B in FIG. 11A). Subsequently, the pulsed laser beam is shifted by the set line pitch (0.059 mm) to the other side in the front-rear direction Y (the right side R in FIG. 11A). Then, the pulsed laser beam is again shifted by the set line pitch (0.059 mm) to the other side in the front-rear direction Y (the front side F in FIG. 11A). Subsequently, the pulsed laser beam is again shifted by the set line pitch (0.059 mm) to the other side in the left-right direction X (the right side R in FIG. 11A) to the other side in the front-rear direction Y (the rear side B in FIG. 11A). Thereafter, the pulsed laser irradiation is repeated until the pulsed laser irradiation proceeds in one or the other direction in the front-to-back direction Y and reaches the tip (the side marked "end point" in Figure 11(A)) of the other side (the right side R in Figure 11(A)) along the left-to-right direction X in the lid undersurface roughened region F2.

[0060] By irradiating the roughened under-lid surface region F2 with a pulsed laser in this manner, a basic layer 35 and a column layer 36 are formed. First, debris particles from the lid member 30 adhere to the surface of the lid member 30 in a scattered manner, forming a planar basic layer 35. Next, as the scattered adhesion of the debris particles progresses, the debris particles bond to the basic layer 35, forming a two-dimensional forest of numerous short, protruding nanocolumns 361 extending in the height direction. As the scattered adhesion of the debris particles progresses further, the debris particles bond to the basic layer 35 in a string-like pattern, forming a two-dimensional forest of numerous long, columnar nanocolumns 361 extending in the height direction. Note that, for example, by increasing the energy density of the pulsed laser irradiation, nanocolumns 361 with a high average height can be formed.

[0061] Furthermore, the position where pulsed laser irradiation of the roughened lid lower surface region F2 starts (the side marked "start point" in FIG. 11(A)) is not limited to that shown in FIG. 11(A), and the side marked "end point" in FIG. 11(A) may be the position where pulsed laser irradiation starts. Furthermore, pulsed laser irradiation of the roughened lid upper surface region F1 is also performed in the same manner as pulsed laser irradiation of the roughened lid lower surface region F2 shown in FIG. 11(A). However, pulsed laser irradiation of the roughened lid upper surface region F1 and pulsed laser irradiation of the roughened lid lower surface region F2 may be performed in different ways.

[0062] As shown in FIG. 11B, the roughened terminal side surface region F3 is irradiated with a pulsed laser beam traveling in one direction along the second direction P of the positive terminal member 50 at the tip of one side of the roughened terminal side surface region F3 along the third direction Q of the positive terminal member 50 (the side marked "start point" in FIG. 11B). Subsequently, the pulsed laser beam is shifted toward the other side of the positive terminal member 50 along the third direction Q by the set line pitch (0.059 mm) and irradiated in the other direction along the second direction P. Then, the pulsed laser beam is shifted toward the other side of the positive terminal member 50 along the third direction Q by the set line pitch (0.059 mm) and irradiated again in one direction along the second direction P. Subsequently, the pulsed laser beam is repeatedly irradiated in one direction or the other along the second direction P until it reaches the tip of the other side of the roughened terminal side surface region F3 along the third direction Q (the side marked "end point" in FIG. 11B).

[0063] By irradiating the terminal side surface roughened region F3 with a pulsed laser in this manner, a base layer 55 and a column layer 56 are formed. First, debris particles from the positive electrode terminal member 50 adhere to the surface of the positive electrode terminal member 50 in a scattered manner, forming a planar base layer 55. Next, as the scattered adhesion of the debris particles progresses, the debris particles bond to the base layer 55, forming a two-dimensional forest of numerous short, protruding nanocolumns 561 extending in the height direction. As the scattered adhesion of the debris particles progresses further, the debris particles bond to the base layer 55 in a string-like pattern, forming a two-dimensional forest of numerous long, columnar nanocolumns 561 extending in the height direction. Note that, for example, by increasing the energy density of the pulsed laser irradiation, nanocolumns 561 with a high average height can be formed.

[0064] Furthermore, the position where pulsed laser irradiation of the roughened terminal side surface region F3 starts (the side marked "start point" in FIG. 11(B)) is not limited to that shown in FIG. 11(B), and the side marked "end point" in FIG. 11(B) may be the position where pulsed laser irradiation starts. Furthermore, pulsed laser irradiation of the roughened terminal lower surface region F4 is performed in the same manner as pulsed laser irradiation of the roughened terminal side surface region F3 shown in FIG. 11(B). However, in this case, the direction of pulsed laser irradiation is the same as that of laser irradiation of the roughened terminal side surface region F3, but the start and end positions of pulsed laser irradiation are at the ends of one side and the other side of the roughened terminal lower surface region F4 along the second direction P of the positive electrode terminal member 50. Furthermore, the direction in which pulsed laser irradiation is shifted by the set line pitch (0.059 mm) is one side of the second direction P of the positive electrode terminal member 50.

[0065] In the laser irradiation step S2, the joining region of the lid member 30 around the negative electrode insertion hole 34h with the negative electrode resin member 80 is irradiated with pulsed laser in substantially the same manner as the roughened lid upper surface region F1 and the roughened lid lower surface region F2. Similarly, the joining region of the negative electrode terminal member 60 with the negative electrode resin member 80 is irradiated with pulsed laser in substantially the same manner as the roughened terminal side surface region F3 and the roughened terminal lower surface region F4. Here, "substantially the same manner" refers to the region to be irradiated with pulsed laser and the conditions for pulsed laser irradiation.

[0066] Following the laser irradiation step S2, the insert molding step S3 is performed. In the insert molding step S3, a positive electrode resin member 70 and a negative electrode resin member 80 are formed, and the positive electrode resin member 70 is joined to the lid member 30 and the positive electrode terminal member 50 to form an integrated body, and the negative electrode resin member 80 is joined to the lid member 30 and the negative electrode terminal member 60 to form an integrated body. In other words, the unit member 1A, which is a metal-resin composite, is produced. FIG. 12 is an explanatory diagram schematically illustrating the insert molding step S3 on the positive electrode terminal member 50 side.

[0067] In the insert molding step S3, a mold DE is used. The mold DE has a lower mold DE1 disposed on the lower side and an upper mold DE2 disposed on the upper side. First, the lower mold DE1 and the upper mold DE2 are set together to place the lid member 30, the positive electrode terminal member 50, and the negative electrode terminal member 60 in their predetermined positions. At this time, the mold DE integrally supports the positive electrode terminal member 50 inserted into the positive electrode insertion hole 33h, the negative electrode terminal member 60 inserted into the negative electrode insertion hole 34h, and the lid member 30. The set lower mold DE1 and upper mold DE2 also form spaces corresponding to the positive electrode resin member 70 and the negative electrode resin member 80.

[0068] In the insert molding process S3, a filling process S31 is performed first, followed by a solidification process S32. In the filling process S31, as shown in FIG. 12 , molten resin MR, which is the material for the positive electrode resin member 70 and the negative electrode resin member 80, is injected from the gate member GT through the upper mold DE2 into the space formed by the lower mold DE1 and the upper mold DE2. At this time, for example, the molten resin MR fills the gaps between the numerous nanocolumns 361 that make up the column layer 36 until it reaches the base layer 35. Similarly, the molten resin MR fills the gaps between the numerous nanocolumns 561 that make up the column layer 56 until it reaches the base layer 55.

[0069] The materials for the positive electrode resin member 70 and the negative electrode resin member 80 are primarily composed of polyphenylene sulfide and contain glass filler. The linear expansion coefficients of the materials for the positive electrode resin member 70 and the negative electrode resin member 80 are set between the linear expansion coefficient of copper (1.65) and the linear expansion coefficient of aluminum (2.31).

[0070] After the injection of the molten resin MR is completed, the molten resin MR is appropriately cooled in the solidification step S32 to form the positive electrode resin member 70 and the negative electrode resin member 80. Specifically, for example, the molten resin MR filled in the gaps between the numerous nanocolumns 361 in the filling step S31 until it reaches the base layer 35, and the molten resin MR filled in the gaps between the numerous nanocolumns 561 until it reaches the base layer 55, solidifies, forming the positive electrode resin member 70 bonded to the bonding regions E1 to E4 including the roughened regions F1 to F4. Similarly, the negative electrode resin member 80 is also formed. Then, the upper mold DE2 is moved upward, and the unit member 1A consisting of the integrated lid member 30, positive electrode resin member 70, positive electrode terminal member 50, negative electrode resin member 80, and negative electrode terminal member 60 is removed from the lower mold DE1.

[0071] Following the insert molding step S3, a lid assembly completion step S4 is performed. In the lid assembly completion step S4, the lid assembly is completed. Specifically, an electrode body 40 is prepared, and the positive electrode terminal lower portion 52 and the negative electrode terminal lower portion 62 of the unit member 1A produced in the insert molding step S3 are welded and connected to the positive electrode current collecting portion 41r and the negative electrode current collecting portion 42r of the electrode body 40, respectively. The electrode body 40 in this state is then wrapped in a bag-shaped insulating holder 5. As a result, a lid assembly consisting of the lid member 30, positive electrode terminal member 50, negative electrode terminal member 60, positive electrode resin member 70, negative electrode resin member 80, electrode body 40, and insulating holder 5 is completed.

[0072] The lid assembly completion step S4 is followed by the closing step S5. In the closing step S5, the main body member 20 is prepared, and the portion of the lid assembly completed in the lid assembly completion step S4 below the lid member 30, including the electrode body 40 and the insulating holder 5, is inserted into the main body member 20, and the opening 21 of the main body member 20 is closed with the lid member 30.

[0073] After the closing step S5, a welding step S6 is performed. In the welding step S6, the leading ends of the front side portion 13, the rear side portion 14, the left side portion 15, and the right side portion 16 of the main body member 20 are laser-welded to the peripheral edge of the cover member 30 along the entire periphery, thereby airtightly sealing the opening 21.

[0074] Following the welding step S6, a liquid injection and sealing step S7 is performed. In the liquid injection and sealing step S7, the electrolyte 3 is injected into the case 10 through the liquid injection hole 30k, and the electrolyte 3 is impregnated into the electrode body 40. Thereafter, the sealing member 39 is fitted into the liquid injection hole 30k from the upper side U, and the sealing member 39 is welded to the lid member 30 around its entire periphery, thereby airtightly sealing the gap between the sealing member 39 and the lid member 30.

[0075] Following the liquid injection and sealing step S7, a charging and aging step S8 is performed. In the charging and aging step S8, a charging device (not shown) is connected to the battery 1, and the battery 1 is initially charged. After that, the initially charged battery 1 is left for a predetermined time, and the battery 1 is aged. In this way, the battery 1 is completed.

[0076] Next, an experiment to verify the sealing performance of the joint between a metal member and a resin member will be described. The experiment was conducted by the applicant. The experiment will be referred to as the "sealing performance verification experiment." The sealing performance verification experiment consists of the following three steps (1) to (3). (1) Production of test specimens (2) Liquid bath thermal shock test (3) Helium leak test

[0077] First, (1) the fabrication of the test specimen will be explained. The test specimen is the subject of the sealing performance verification experiment. Figure 13 is an explanatory diagram that shows a schematic representation of the test specimen. In detail, Figure 13(A) is a plan view of the test specimen, and Figure 13(B) is a DD cross-sectional view of Figure 13(A). The test specimen is formed by joining a plate-shaped metal member and a resin member. The plate-shaped metal member is made of aluminum or copper. That is, the test specimens include those in which the plate-shaped metal member is made of aluminum and those in which the plate-shaped metal member is made of copper. The resin member is made of a single type of polyphenylene sulfide (PPS).

[0078] Regardless of the type of metal member, the plate-shaped metal member is generally formed in a square shape. A ventilation hole is formed at the center of the metal member in a plan view, penetrating the metal member in the thickness direction.

[0079] A roughened region was formed on the surface of the metal component that was to be bonded to the resin component. The roughened region was shaped like a ring that surrounded the edge of the air vent with a roughly constant width. Similar to the roughened regions F1 to F4 described above, a base layer and a pillar group layer were layered in the roughened region by pulsed laser irradiation. However, in the sealability verification experiment, multiple test specimens were prepared, and pulsed laser irradiation was performed under different conditions for each test specimen. As a result, the average height and surface area ratio of the nanocolumns also varied depending on the test specimen. Figure 14 is a table showing the relationship between the various pulsed laser irradiation conditions for the roughened region and the average height and surface area ratio of the nanocolumns formed in the roughened region. For the sealability verification experiment, seven aluminum metal components and seven copper metal components were prepared.

[0080] Then, a resin member is bonded to each metal member by insert molding. The resin member is shaped like a circular plate. The central axis of the resin member and the central axis of the air vent are approximately aligned. Therefore, in this experiment, the bonded area between the resin member and the metal member is aligned with the roughened area of ​​the metal member. Furthermore, the resin member is bonded to the roughened area around the entire periphery of the air vent, completely covering the air vent. In other words, in this experiment, the bonded portion between the resin member and the metal member seals the space (first space) on the side of the metal member constituting the test specimen that is bonded to the resin member and the space (second space) on the side that is not bonded to the resin member.

[0081] Next, (2) Liquid Bath Thermal Shock Test will be explained. A liquid bath thermal shock test was performed on each test specimen using a commercially available liquid bath thermal shock device (ES-96EXH-LS, Hitachi Appliances, Inc.).

[0082] Finally, (3) helium leak test will be explained. A known helium leak test was performed on each test specimen that had undergone the liquid bath thermal shock test using a commercially available helium leak detector (HELiOT900, ULVAC, Inc.).

[0083] (3) The results of the helium leak test are shown in Figure 15. Figure 15(A) is a scatter plot with the average height of the nanocolumns plotted on the horizontal axis and the helium leak rate plotted on the vertical axis, and Figure 15(B) is a scatter plot with the surface area ratio plotted on the horizontal axis and the helium leak rate plotted on the vertical axis. The vertical axes in Figures 15(A) and 15(B) indicate that the helium leak rate decreases as you move up the axis. As shown in Figure 15, the sealing verification experiment showed that the sealing performance of the joint between the metal and resin components was good when the average height of the nanocolumns was 84 nm or more or the surface area ratio was 12.9 or more.

[0084] Here, we will explain how to calculate the average height of the nanocolumns in each roughened region in the sealing performance verification experiment. In this calculation method, a plate-shaped metal member is first prepared as a test piece. This metal member test piece is referred to as the "average height test piece." Then, a pulsed laser is irradiated onto the entire surface of one of the average height test pieces under various conditions.

[0085] Next, a cross-sectional sample including the flat portion irradiated with the pulsed laser is prepared from each average height test piece using a predetermined cross-sectional sample preparation device (e.g., a Cross Section Polisher (registered trademark): manufactured by JEOL Ltd.). The cross-sectional sample is parallel to the thickness direction of the average height test piece. Next, a cross-sectional image of each cross-sectional sample is obtained using a scanning electron microscope (S-4800, Hitachi High-Technologies Corporation). The magnification of this cross-sectional image is 150,000 times.

[0086] Next, the cross-sectional area and base length of the nanocolumns in each cross-sectional image are measured using known image processing software, and the height of the nanocolumns is calculated using the following equation 1.

number

[0087] Figure 16(A) is an example of a cross-sectional image obtained using a scanning electron microscope, and Figure 16(B) is an explanatory diagram illustrating the cross-sectional area and base length of the nanocolumns based on Figure 16(A). As shown in Figure 16(B), the length of the curved portion is the base length, and the total area of ​​the forest of nanocolumns is the cross-sectional area of ​​the nanocolumns. Note that one scale interval in the lower right corner of the images in Figures 16(A) and 16(B) represents 30 nm.

[0088] Next, a method for calculating the surface area ratio of each roughened region in a sealing performance verification experiment will be described. In this calculation method, a plate-shaped metal member is first prepared as a test piece. This metal member test piece is referred to as a "surface area ratio test piece." Then, one plane of each surface area ratio test piece is irradiated with a pulsed laser under various conditions. In this experiment, the target of pulsed laser irradiation is one of the planes. Next, the specific surface area of ​​the surface area ratio test piece that has been irradiated with the pulsed laser is measured using a common krypton gas adsorption method.

[0089] Next, based on the measured specific surface area of ​​the surface area ratio test piece, the roughened surface area of ​​the plane irradiated with the pulsed laser on the surface area ratio test piece is calculated. The roughened surface area is calculated using the following Equation 2.

number

[0090] Furthermore, based on the calculated roughened surface area of ​​the surface area ratio test piece, the surface area ratio of the plane irradiated with the pulsed laser in the surface area ratio test piece is calculated. The surface area ratio is calculated using the following Equation 3.

number

[0091] As described above, the lid member 30 has bonding regions E1 and E2, to which the positive electrode resin member 70 is bonded on its surface, sealing the first space outside the battery 1 and the second space inside the battery 1 together with the positive electrode resin member 70. The bonding regions E1 and E2 include roughened regions F1 and F2 formed on the surface of the lid member 30 and including a base layer 35 formed by the accumulation of debris particles and a column group layer 36 formed by the debris particles being linked to the base layer 35 in a string-like pattern, forming a two-dimensional forest of nanocolumns 361 extending in the height direction. The average height of the forest of nanocolumns 361 is 84 nm or more, which improves the sealing performance of the bonding surface with the positive electrode resin member 70 compared to, for example, a metal member having protruding portions that cannot be considered columnar portions. Similarly, in the case of a positive electrode terminal member 50 having bonding regions E3 and E4, the bonding regions E3 and E4 include roughened regions F3 and F4 formed on the surface of the positive electrode terminal member 50, in which a base layer 55 formed by the accumulation of debris particles and a column group layer 56 formed by the debris particles being linked to the base layer 55 in a string-like pattern and forming a two-dimensional forest of nanocolumns 561 extending in the height direction, and the average height of the forest of nanocolumns 561 is 84 nm or more, thereby improving the sealing property of the bonding surface with the positive electrode resin member 70 compared to, for example, a metal member having protruding portions that cannot be considered columnar portions.

[0092] In addition, the bonding regions E1 and E2 are formed in a ring shape so as to surround the entire edge of the positive electrode insertion hole 33h, and the roughened regions F1 and F2 are formed in a ring shape in the bonding regions E1 and E2 so as to follow the shape of the bonding regions E1 and E2, thereby improving the sealing ability of the positive electrode insertion hole 33h when the bonding regions E1 and E2 are bonded to the positive electrode resin member 70.

[0093] Furthermore, the resin forming the positive electrode resin member 70 bonded to the bonding regions E1 and E2 fills the gaps between the nanocolumns 361 while reaching the base layer 35, thereby improving the sealing performance of the bonded portion between the cover member 30 and the positive electrode resin member 70. Similarly, the resin forming the positive electrode resin member 70 bonded to the bonding regions E3 and E4 fills the gaps between the nanocolumns 561 while reaching the base layer 55, thereby improving the sealing performance of the bonded surface between the positive electrode terminal member 50 and the positive electrode resin member 70.

[0094] Furthermore, a manufacturing method for a lid member 30 as a metal member includes a laser irradiation step S2 in which aluminum-derived debris particles, which are the material for the lid member 30, are generated by pulsed laser irradiation on the surface of the lid member 30 that can become roughened regions F1 and F2 when the base layer 35 and the column layer 36 are not yet formed, and the debris particles grow into nanocolumns 361 to form roughened regions F1 and F2, thereby forming a forest of nanocolumns 361 of 84 nm or larger, thereby obtaining a lid member 30 with excellent sealing properties. Similarly, a manufacturing method for a positive electrode terminal member 50 includes a laser irradiation step S2 in which aluminum-derived debris particles, which are the material for the positive electrode terminal member 50, are generated by pulsed laser irradiation on the surface of the positive electrode terminal member 50 that can become roughened regions F3 and F4 when the base layer 55 and the column layer 56 are not yet formed, and the debris particles grow into nanocolumns 561 to form roughened regions F3 and F4, thereby obtaining a positive electrode terminal member 50 with excellent sealing properties.

[0095] Furthermore, the method for manufacturing the battery 1 as a metal-resin composite includes a filling step S31 in which molten resin MR, which is the material of the heat-melted positive electrode resin member 70, is used to fill the gaps between the numerous nanocolumns 361 that make up the column layer 36 until it reaches the base layer 35, and also fills the gaps between the numerous nanocolumns 561 that make up the column layer 56 until it reaches the base layer 55; and a solidification step S32 in which the molten resin MR filled in the gaps between the numerous nanocolumns 361 that make up the column layer 36 in the filling step S31 and the molten resin MR filled in the gaps between the numerous nanocolumns 561 that make up the column layer 56 are solidified to form the positive electrode resin member 70 bonded to the roughened regions F1 to F4. This allows the positive electrode resin member 70 to bond to the surfaces of the base layers 35, 55 and the surfaces of the nanocolumns 361, 561, resulting in a battery 1 with high sealing properties.

[0096] As described above, the bonding region of the lid member 30 with the negative electrode resin member 80 is roughened in the same manner as the roughened regions F1 and F2, and is filled with numerous nanocolumns with an average height of 84 nm or more, thereby improving the sealing performance of the bonding region of the lid member 30 with the negative electrode resin member 80. Furthermore, the bonding region of the negative electrode terminal member 60 with the negative electrode resin member 80 is roughened in the same manner as the roughened regions F3 and F4, and is filled with numerous nanocolumns with an average height of 84 nm or more, thereby improving the sealing performance of the bonding region of the negative electrode terminal member 60 with the negative electrode resin member 80.

[0097] It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Naturally, the present invention can be improved and modified in various ways without departing from the spirit and scope of the present invention. Improved examples and modifications of the present embodiment will be described below.

[0098] In this embodiment, a flat wound electrode body 40 is exemplified as the electrode body housed in the case 10, but the electrode body may be a laminated electrode body. Also, in this embodiment, one electrode body is housed in the case 10, but multiple electrode bodies may be housed in the case 10.

[0099] In this embodiment, the case 10 has an overall flat, bottomed rectangular parallelepiped shape; however, the shape of the case 10 can be modified as appropriate and may have other shapes, such as a cylindrical shape. The shapes of one or both of the positive electrode terminal member 50 and the negative electrode terminal member 60 may also be modified as appropriate. Similarly, the shapes of one or both of the positive electrode resin member 70 and the negative electrode resin member 80 may also be modified as appropriate. Furthermore, in this embodiment, the shapes of the positive electrode terminal member 50 and the negative electrode terminal member 60 are identical, but they may be different. Similarly, in this embodiment, the shapes of the positive electrode resin member 70 and the negative electrode resin member 80 are identical, but they may be different.

[0100] In this embodiment, a battery 1 in which a metal cover member 30 and a metal positive terminal member 50 are each joined to a positive electrode resin member 70, and in which a metal cover member 30 and a metal negative terminal member 60 are each joined to a negative electrode resin member 80, is included in the metal resin composite of the present invention, and the unit member 1A that constitutes the battery 1 is also included in the metal resin composite of the present invention.

[0101] In this embodiment, the present invention is applied to a lithium ion battery, but it can also be applied to any general power storage device, such as a nickel-metal hydride battery or a nickel-cadmium battery. Furthermore, the use of the present invention is not limited to batteries, but can be widely applied to composites that join metal members and resin members.

[0102] In this embodiment, the positive electrode resin member 70 reaches the base layer 35 in the roughened regions F1 and F2 and the base layer 55 in the roughened regions F3 and F4. However, for example, the positive electrode resin member 70 may be filled into the gaps between the numerous nanocolumnar bodies 361 or the gaps between the numerous nanocolumnar bodies 561 so that the positive electrode resin member 70 as a whole reaches the tips of the nanocolumnar bodies 361 and 561, the part between the tips and the middle, approximately the middle, or the part between the middle and the base.

[0103] In this embodiment, the roughened regions F1 and F2 are formed over the entire bonding regions E1 and E2, but they may be formed only in parts of the bonding regions E1 and E2. In this case, however, it is preferable that the roughened regions F1 and F2 are formed in an annular shape in the bonding regions E1 and E2 so as to surround the positive electrode insertion hole 33h. In addition, the roughened regions F3 and F4 are formed over the entire bonding regions E3 and E4, but they may be formed only in parts of the bonding regions E3 and E4. In this case, it is preferable that the roughened region F3 is formed over the entire portion of the positive electrode terminal intermediate portion 53 in the bonding region E3. In addition, it is preferable that the roughened region F4 be formed in an annular shape along the periphery of the bonding region E4. [Explanation of symbols]

[0104] 1... battery, 10... case, 20... main body member, 30... cover member, 33h… Positive electrode insertion hole, 34h… Negative electrode insertion hole 50… positive end component, 60… negative end component, 70… Resin components for positive electrode, 80… Resin components for negative electrode, 30a, 50a... protrusions 35, 55… base layer, 36, 56… column group layer, 361, 561… columnar body, E1…Top joint area, E2…Bottom joint area E3… Terminal side bonding area, E4… Terminal bottom bonding area F1... covers the upper roughening area, F2... covers the lower roughening area. F3…Roughening area on the side of the terminal, F4…Roughening area under the terminal.

Claims

1. a bonding area on a surface of the resin member that is bonded to the resin member to seal the gap between the first space and the second space together with the resin member; the bonding region includes a roughened region formed on the surface and including a base layer formed by the accumulation of debris particles, and a pillar group layer formed by a two-dimensional forest of nano-columns formed by the debris particles linked together in a string from the base layer and extending in a height direction, a metal member in which the average height of the nanocolumns in the roughened region is 84 nm or more; a resin member joined to the joining region, A metal-resin composite in which the resin forming the resin member reaches the base layer and fills the gaps between the nanocolumnar bodies.

2. The metal-resin composite according to claim 1, The first space is disposed outside the bonding area, and the second space is disposed inside the bonding area, The bonding region is formed in an annular shape, The roughened region is formed in a ring shape that conforms to the shape of the bonding region.

3. The method for producing a metal-resin composite according to claim 1 or 2, a laser irradiation step of depositing debris particles derived from the metal member by irradiating the metal member with a pulsed laser on a surface of the metal member that can become the roughened region in a state where the column group layer has not yet been formed, and growing the particles into nanocolumns to form the roughened region; a filling step of filling the gaps between the nanocolumns constituting the column group layer with a thermally melted molten resin until the gaps reach the base layer; a solidification step of solidifying the molten resin filled in the gaps between the nanocolumns that form the column group layer in the filling step to form a resin member bonded to the roughened region. Method for manufacturing metal-resin composites.

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