Method for manufacturing terminal component for battery

Abstract

The present invention inhibits occurrence of burrs in an outer edge portion of an individual clad piece. A method for manufacturing a terminal component has: a step (1) in which, when disposing an individual clad piece 31 obtained by laminating and joining a high-ductility conductor layer 31A and a low-ductility conductor layer 31B in the thickness direction, the high-ductility conductor layer 31A is disposed, in the lower mold 50, in contact with the bottom surface 52 of a vertical hole part 51 having an upward opening; and a step (2) in which, when inserting an upper mold 55A into the vertical hole part 51 of the lower mold 50 and pressing the upper surface of the low-ductility conductor layer 31B of the individual clad piece 31, by means of a projection part forming recess part 56 which has a downward opening, extends in the upper direction, and is for forming a projection part 32C to serve as a shaft portion at the center of the individual clad piece 31, the individual clad piece 31 is plastically deformed in the upper mold 55A toward the projection part forming recess part 56 while the side surfaces of the individual clad piece 31 are restrained from plastic deformation by means of the inner peripheral wall 53 of the vertical hole part 51 of the lower mold 50, and the projection part 32C is formed within the projection part forming recess part 56.

Description

Manufacturing method for battery terminal parts

[0001] The present invention relates to a method for manufacturing a battery terminal component, for example, a method for manufacturing a battery terminal component used in a secondary battery module such as a lithium ion secondary battery.

[0002] Patent Document 1 describes a lithium ion secondary battery (LIB) including a positive electrode made of aluminum foil, a negative electrode made of copper foil, a separator between the positive electrode and the negative electrode, and an electrolyte, with the positive electrode, negative electrode, separator, and electrolyte housed in a case. In the LIB, the positive electrode is connected to a positive electrode current collector in the case, and the positive electrode current collector is electrically connected to a positive electrode terminal that penetrates the case. The positive electrode terminal is connected to a bus bar outside the case. Meanwhile, the negative electrode is connected to a negative electrode current collector in the case, and the negative electrode current collector is electrically connected to a negative electrode terminal that penetrates the case. The negative electrode terminal is also connected to a bus bar outside the case.

[0003] In recent years, bus bars (Al bus bars) made of aluminum or aluminum alloys have been used to reduce weight. Therefore, in LIBs, a positive electrode terminal made of aluminum or an aluminum alloy is used to connect a positive electrode current collector made of aluminum or an aluminum alloy to the Al bus bar. Meanwhile, copper or a copper alloy is used for the negative electrode current collector. Therefore, Patent Document 1 describes that the portion of the negative electrode terminal that contacts the negative electrode current collector is made of copper or a copper alloy, and the portion that contacts the Al bus bar is made of aluminum or an aluminum alloy.

[0004] Specifically, the negative electrode terminal of Patent Document 1 has a shaft portion and a flange portion extending radially from the shaft portion, and is composed of a clad material in which a high-ductility conductor layer made of aluminum or an aluminum alloy and a low-ductility conductor layer made of copper or a copper alloy are bonded together. In Patent Document 1, the outer shape of the terminal component is formed by press-molding a two-layer clad piece made of two types of metal. Specifically, the clad material is placed in a lower mold having a recess corresponding to the shaft portion, with the low-ductility conductor layer facing downward, and is forged and pressed from the high-ductility conductor layer side by an upper mold. This forms a shaft portion with a protruding center on the low-ductility conductor layer side, and the remaining portion of the clad material forms the flange, forming a battery terminal.

[0005] Patent Document 2 describes a terminal component for a secondary battery having a plate-shaped head having a bottom surface and an upper surface opposite the bottom surface, and a shaft extending from the bottom surface. The terminal component includes copper (a low-ductility conductor) and aluminum (a high-ductility conductor). The bottom surface of the head is made of copper, and the upper surface of the head is made of aluminum. Patent Document 2 describes providing a circumferentially continuous chamfered portion on the outer periphery of the bottom surface of the head to prevent burrs from occurring when a high-ductility conductor layer made of aluminum on the upper surface of the head, which is more susceptible to plastic deformation than copper, flows quickly and enters a gap between the low-ductility conductor layer made of copper on the bottom surface of the head and a mold.

[0006] Japanese Patent No. 6581440 Japanese Patent Application Laid-Open No. 2023-62844

[0007] When forging a two-layer clad piece having a high-ductility conductor layer made of aluminum or an aluminum alloy and a low-ductility conductor layer made of copper or a copper alloy, the low-ductility conductor layer is placed facing downward in a lower die having a recess corresponding to the shaft portion, and the upper die forges the clad piece from the high-ductility conductor layer side. This can cause the high-ductility conductor layer to penetrate between the lower and upper dies at the outer edge of the clad piece, resulting in the formation of burrs. Such burrs require the effort of removing them from the formed clad piece. Furthermore, if burrs become loose from the formed clad piece and remain in the lower or upper die after the clad piece is removed from the die, they can interfere with the formation of the next clad piece. This requires the effort of cleaning the lower or upper die, where loose burrs may remain.

[0008] The object of the present invention is to suppress the occurrence of burrs between a lower mold and an upper mold at the outer edge of a clad piece when manufacturing a terminal part for a battery using a clad plate formed by stacking and bonding a high-ductility conductor layer and a low-ductility conductor layer in the thickness direction, the terminal part having a shaft portion extending in the thickness direction of the clad plate and a flange portion extending from the shaft portion in a direction perpendicular to the thickness direction of the clad plate.

[0009] In order to solve the above problems, a first aspect of the present invention is a method for manufacturing a terminal part for a battery, the terminal part having a stem portion extending in the thickness direction of the clad plate and a flange portion extending from the stem portion in a direction perpendicular to the thickness direction, using a clad plate formed by stacking and bonding a high-ductility conductor layer and a low-ductility conductor layer having lower ductility than the high-ductility conductor layer in the thickness direction, the method comprising the steps of: (1) disposing clad pieces formed by punching the clad plate in the thickness direction in a lower mold so that the high-ductility conductor layer contacts a bottom surface of a vertical hole portion that opens upward in the lower mold; When the upper mold is inserted into the vertical hole portion of the lower mold to press the upper surface of the low-ductility conductor layer of the clad piece, a convex portion forming recess in the upper mold, which opens downward and extends upward to form a convex portion that becomes the axis portion at the center of the clad piece in the orthogonal direction, restrains plastic deformation of the side surface of the clad piece with the inner wall of the vertical hole portion of the lower mold, thereby plastically deforming the clad piece toward the convex portion forming recess, thereby forming the convex portion inside the convex portion forming recess.

[0010] It is preferable that an inclined surface inclined upward toward the center in the orthogonal direction be provided on the inner peripheral edge of the inner peripheral wall of the convex portion-forming concave portion of the upper mold.

[0011] It is preferable that the gradient of the inclined surface of the inner peripheral edge of the upper mold relative to the bottom surface of the vertical hole portion of the lower mold increases toward the center in the orthogonal direction.

[0012] It is preferable that the upper mold has a plurality of flat or curved surfaces that continue from the outer periphery of the lower end toward the center in the orthogonal direction, and that the slope of the plurality of flat or curved surfaces relative to the bottom surface of the vertical hole portion of the lower mold increases toward the center in the orthogonal direction.

[0013] The upper mold preferably has a plurality of conical surfaces that are continuously inclined upward from the outer periphery of the lower end toward the center in the orthogonal direction, and the plurality of conical surfaces preferably have a tapered angle that decreases toward the top.

[0014] In step (2), when the thickness of the high ductility conductor layer at the outer edge of the clad piece is TH and the thickness of the low ductility conductor layer is TL, it is preferable to extend the clad piece into the recess for forming the convex portion of the upper mold until TL / (TH+TL)≦0.2 is satisfied.

[0015] After the step (2), a step (3) may be included in which the protrusion is stretched to form the stem.

[0016] After the step (3), a step (4) of forming a bottomed hole on one end side of the shaft portion may be included.

[0017] After the step (4), a step (5) may be included in which the flange portion extending radially from the shaft portion is formed by pressing the other end side of the shaft portion opposite to the one end side.

[0018] After the step (5), a step (6) of trimming the outermost periphery of the flange portion may be included.

[0019] The steps (1) to (6) are preferably carried out by transfer press molding.

[0020] According to the present invention, in step (1), the high-ductility conductor layer is constrained by a lower mold having a vertical hole that opens upward, and in step (2), the low-ductility conductor layer is pressed from the side using an upper mold having a convex-forming recess that opens downward and extends upward. This reduces the axial component of the pressing force acting on the central portion of the clad piece compared to the outer edge portion, making it easier for the low-ductility conductor layer to plastically flow toward the central portion of the clad piece. This prevents the low-ductility conductor layer from penetrating between the lower mold and the upper mold at the outer edge of the clad piece, thereby preventing burrs from forming in the low-ductility conductor layer between the lower mold and the upper mold. Furthermore, because the high-ductility conductor layer is pressed from the side using the lower mold, this prevents the high-ductility conductor layer from penetrating between the lower mold and the upper mold at the outer edge of the clad piece, thereby preventing burrs from forming in the high-ductility conductor layer between the lower mold and the upper mold.

[0021] 1 is a cross-sectional view of a terminal component 1 according to an embodiment of the battery terminal component of the present invention. FIG. 1 is a cross-sectional view showing a fixing portion between a case 201 and a negative electrode current collector 202 of a battery 200 by the terminal component 1. FIG. 2 is a cross-sectional view showing a step (A) of forming a clad piece 31 (see FIG. 4) from a clad plate 30. FIG. 3 is a cross-sectional view showing a state in which the clad piece 31 is placed on a die 50 serving as a lower mold. FIG. 4 is a cross-sectional view showing a step (B) of forming a convex portion that will become a shaft portion from the clad piece 31. FIG. 5 is a cross-sectional view showing a punch 55B of another form. FIG. 6 is a cross-sectional view showing an intermediate body 32 formed in step (B). FIG. 7 is a cross-sectional view showing a state in which the intermediate body 32 is placed on a die 60. FIG. 8 is a cross-sectional view showing a step (C) of extending the convex portion 32C to form a shaft portion 33C (see FIG. 10). FIG. 9 is a cross-sectional view showing a step (D) of forming an intermediate bottomed hole portion 34D (see FIG. 11) on one end side of the shaft portion 33C. FIG. 11 is a cross-sectional view showing a step (E) of forming a bottomed hole portion 35D (see FIG. 12) on one end side of the shaft portion 34C. FIG. 10 is a cross-sectional view showing a step (F) of forming a flange (original flange shape) by pressing the other end side of the shaft portion 35D.

[0022] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of a battery terminal part according to the present invention will be described by way of configuration examples with reference to the drawings.

[0023] The battery terminal component according to the present invention is formed, for example, in the shape of a rivet. FIG. 1 is a cross-sectional view of a terminal component 1 according to an embodiment of the battery terminal component according to the present invention. As shown in FIG. 1, the terminal component 1 is formed in the shape of a rivet. The terminal component 1 has a shaft portion 10 extending in one direction (Z1 direction) and a flange portion 20 extending from one end of the shaft portion 10 in directions perpendicular to the shaft portion 10 (X1-X2 directions and Y1-Y2 directions perpendicular to X1-X2, Z1-Z2). One end of the shaft portion 10 is provided with a bottomed hole portion 11. The outer periphery of the shaft portion 10 is made of a low-ductility conductor. Furthermore, the flange portion 20 has a surface 21 on the opposite side (Z2 side) from the shaft portion 10 made of a high-ductility conductor, and a surface 22 on the shaft portion 10 side (Z1 side) made of a low-ductility conductor.

[0024] The highly ductile conductor preferably has a standard electrode potential similar to that of the bus bar of the lithium-ion battery. The highly ductile conductor can be made of the same material as the bus bar, such as aluminum or an aluminum alloy. Examples of aluminum include A1050 and A1100 in the A1000 series specified in JIS-H4000:2022. Examples of aluminum alloys include Al-Mn alloys in the A3000 series and Al-Mg alloys in the A5000 series, both of which are specified in the same JIS.

[0025] A low-ductility conductor is a conductor with lower ductility than a high-ductility conductor. Here, "ductility" can be evaluated, for example, by the plastic elongation at the maximum test force specified in JIS-Z2241:2011. The standard electrode potential of a low-ductility conductor is preferably similar to that of the negative electrode current collector of a lithium-ion battery. The low-ductility conductor can be made of a material similar to that of the negative electrode current collector of a lithium-ion battery, such as copper or a copper alloy. Examples of copper include C1020 and C1100 specified in JIS-H3100:2018. Examples of copper alloys include C1441, C1921, C1940, and C7250, all of which are specified in the same JIS.

[0026] 2 is a cross-sectional view showing a portion where a terminal component 1 fixes a case 201 and a negative electrode current collector 202 of a battery 200. As shown in FIG. 2 , a shaft portion 10 of the terminal component 1 penetrates the case 201 and the negative electrode current collector 202 therein from the outside (Z2 side) of the case 201 of the battery 200 toward the inside (Z1 side) of the case 201. Inside the case 201 (Z1 side), the terminal component 1 is crimped by bending and widening the end of the bottomed hole portion 11 of the shaft portion 10 in directions (X1-X2 directions and Y1-Y2 directions) perpendicular to the axial direction (Z1 direction). In this state, the terminal component 1 is electrically connected to the negative electrode current collector 202 and fixes the negative electrode current collector 202 to the case 201. In addition, a packing 207 is provided between the flange 20 of the terminal part 1 and the case 201, and a packing 208 is provided between the case 201 and the negative electrode current collector 202. The packings 207 and 208 prevent the electrolyte from leaking from the battery 200.

[0027] 2, when the terminal component 1 is crimped, the surface 21 of the flange portion 20 of the terminal component 1 on the side opposite to the shaft portion 10 (Z2 side) is in contact with and electrically connected to the bus bar 209. The battery 200 is connected to other batteries and external electronic devices (not shown) via the bus bar 209.

[0028] Hereinafter, a method for manufacturing a battery terminal component according to an embodiment of the present invention will be described with reference to the drawings as appropriate, using the above-described method for manufacturing the terminal component 1 as an example.

[0029] A manufacturing method of a terminal component 1 according to an embodiment of the manufacturing method of a battery terminal component of the present invention includes the following steps (A) to (G): (A) forming a clad piece from a clad plate, (B) forming a convex portion that will become a shaft portion from the clad piece, (C) extending the convex portion to form a shaft portion, (D) forming an intermediate bottomed hole portion on one end of the shaft portion, (E) forming a bottomed hole portion on one end of the shaft portion, (F) pressing the other end of the shaft portion to form a flange portion, and (G) trimming the outermost periphery of the flange portion.

[0030] The above steps (A) to (G) are preferably carried out by transfer press molding. Each step will be described below.

[0031] (A) Step of forming clad pieces from a clad plate FIG. 3 is a cross-sectional view illustrating step (A) of forming clad pieces 31 (see FIG. 4) from a clad plate 30. As shown in FIG. 3, the clad plate 30 is formed by stacking and bonding a high-ductility conductor layer 30A and a low-ductility conductor layer 30B, which has lower ductility than the high-ductility conductor layer 30A, in the thickness direction (Z1, Z2 directions). The high-ductility conductor layer 30A is a layer made of a conductor having a standard electrode potential similar to that of a battery bus bar. For example, aluminum or an aluminum alloy can be used for the high-ductility conductor layer 30A. The low-ductility conductor layer 30B is a layer made of a conductor having lower ductility than the high-ductility conductor and a standard electrode potential similar to that of a negative electrode current collector of a battery. For example, copper or a copper alloy can be used for the low-ductility conductor layer 30B.

[0032] To form the clad pieces 31 (see FIG. 4 ) from the clad plate 30, as shown in FIG. 3 , a press machine or the like is used to place the clad plate 30 above (Z1 side) a die 40 having a hole 41 of a predetermined shape, and a punch 42 having a predetermined shape is lowered from above (Z1 side) to perform a punching process. The predetermined shape here refers to a shape corresponding to the shape of the clad piece 31. This allows the clad piece 31 to be produced from the clad plate 30. In this case, as shown in FIG. 3 , a guide 43 for guiding the punch 42 may be provided. Note that FIG. 3 shows a configuration in which punching is performed with the clad plate 30 positioned so that the high ductility conductor layer 30A contacts the die 40, but punching may also be performed with the clad plate 30 positioned so that the low ductility conductor layer 30B contacts the die 40.

[0033] 4 and 5 are cross-sectional views for explaining step (B) of forming a convex portion 32C (see FIG. 7) that will become a shaft portion 33C (see FIG. 10) from the clad piece 31. Fig. 4 shows the step of placing the clad piece 31 in the die 50 in step (B). Fig. 5 shows the step of forming a convex portion 32C that will become a shaft portion 33C from the clad piece 31 in step (B).

[0034] First, as shown in FIG. 4 , when a clad piece 31 formed by punching a clad plate 30 in the thickness direction (Z2 direction) is placed in a die 50 serving as a lower mold, the clad piece 31 is placed so that the high ductility conductor layer 31A contacts the bottom surface 52 of a vertical hole portion 51 that opens upward (toward the Z1 side) in the die 50. At this time, the inner peripheral wall of the vertical hole portion 51 of the die 50 is positioned slightly outward from the outer peripheral end surface (side surface perpendicular to the Z1 and Z2 directions) of the clad piece 31. Therefore, the inner peripheral wall 53 of the vertical hole portion 51 of the die 50 and the outer peripheral end surface of the clad piece 31 are close to each other and form a clearance fit, so that the outer peripheral end surface (side surface perpendicular to the Z1 and Z2 directions) and the lower surface (surface on the Z2 side) of the high ductility conductor layer 31A are constrained by the die 50. Note that the die 50 is an example of a lower mold in the present invention.

[0035] 5, when punch 55A serving as an upper mold is inserted into vertical hole 51 of die 50 to press the upper surface (surface on the Z1 side) of low ductility conductor layer 31B of clad piece 31, punch 55A presses low ductility conductor layer 31B of clad piece 31 from the outer periphery of the upper surface with convexity-forming recess 56 that opens downward (to the Z2 side) and extends upward (to the Z1 side) to form convexity 32C (see FIG. 7) that becomes shank 10 at the center in directions (X1-X2 directions and Y1-Y2 directions) perpendicular to the thickness direction of clad piece 31. As a result, plastic deformation of the outer periphery side surface (surface perpendicular to the Z1-Z2 directions) of clad piece 31 is constrained by inner circumferential wall 53 of vertical hole 51 of die 50, and clad piece 31 is plastically deformed toward convexity-forming recess 56, whereby convexity 32C can be formed inside convexity-forming recess 56. The punch 55A is an example of the upper die in the present invention.

[0036] Punch 55A has a convex-forming recess 56 that opens downward (toward the Z2 side) and extends upward (toward the Z1 side) at the center in directions (X1-X2 and Y1-Y2 directions) orthogonal to its axial direction (Z1-Z2 directions). The axial direction of punch 55A corresponds to the thickness direction of the clad plate 30 and the clad pieces 31. The direction orthogonal to the axial direction of punch 55A corresponds to the direction orthogonal to the thickness direction of the clad plate 30 and the clad pieces 31. In punch 55A, convex-forming recess 56 may be configured as a hole that penetrates in the up-down direction (Z1-Z2 directions), or as a non-penetrating recess.

[0037] As described above, by pressing the low-ductility conductor layer 31B of the clad piece 31 with the punch 55A while constraining the plastic deformation of the outer peripheral side surface (surface perpendicular to the Z1 and Z2 directions) of the clad piece 31 with the inner peripheral wall 53 of the vertical hole portion 51 of the die 50, the clad piece 31 can be plastically deformed toward the convex-forming recess 56 of the punch 55A. In the thickness direction (Z1 and Z2 directions) of the clad piece 31, the stress acting on the central portion of the clad piece 31 due to the pressing of the convex-forming recess 56 of the punch 55A is smaller than the stress acting on the outer edge portion of the clad piece 31. Therefore, the low-ductility conductor layer 31B is more likely to plastically flow toward the central portion of the clad piece 31, and the generation of burrs due to distorted plastic flow of the low-ductility conductor layer 31B on the upper surface (Z1 side) of the outer edge portion of the clad piece 31 can be suppressed.

[0038] 5, the inner peripheral edge of the convex-forming recess 56 of the punch 55A is preferably provided with an inclined surface 57 that is inclined upward (toward the Z1 side) toward the inside (the center of the clad piece 31). By providing the inclined surface 57 on the inner peripheral edge of the convex-forming recess 56 of the punch 55A, the low-ductility conductor layer 31B can be plastically flowed upward (toward the Z1 side) along the inclined surface 57 inside the convex-forming recess 56.

[0039] The gradient of the inclined surface 57 of the convex-forming recess 56 of the punch 55A relative to the bottom surface 52 of the vertical hole 51 of the die 50 preferably increases toward the inside (the center of the clad piece 31). That is, assuming a tangent surface to the inclined surface 57, the angle between the outer peripheral surface of the punch 55A and the tangent surface to the inclined surface 57 is preferably less than 90 degrees and gradually decreases from the outer peripheral side of the punch 55A toward the inside (the center of the clad piece 31). In practice, in a cross section (cross section shown in FIG. 5 ) taken along the axial direction (Z1, Z2 directions) of the punch 55A, the angle between the line indicating the outer peripheral surface of the punch 55A and the line (tangent) indicating the tangent surface to the inclined surface 57 is preferably less than 90 degrees and gradually decreases from the outer peripheral side of the punch 55A toward the inside (the center of the clad piece 31). When the gradient of the inclined surface 57 increases toward the inside (the center of the clad piece 31), the stress acting on the clad piece 31 due to pressing decreases from the outer edge portion toward the center portion of the clad piece 31. This makes it easier for the plastic flow of the clad piece 31 to move toward the center in the X direction (the center of the clad piece 31), making it easier to cause the low-ductility conductor layer 31B to plastically flow toward the convex-forming recess 56. When pressing the clad piece 31 with the punch 55A, a guide 59 may be used to guide the punch 55A in the up and down directions (Z1 and Z2 directions).

[0040] Although the punch 55A shown in Figure 5 has an inclined surface 57 whose slope increases continuously toward the center of the clad piece 31, punches of other shapes, such as punch 55B shown in Figure 6, may also be used.

[0041] FIG. 6 is a cross-sectional view showing another embodiment of a punch 55B. As shown in FIG. 6, the punch 55B has a shape different from that of the punch 55A shown in FIG. 5. The punch 55B has multiple inclined surfaces 57A, 57B, 57C, and 57D that continue from the outer periphery of its lower end toward the inside (the center of the clad piece 31). The inclined surfaces 57A to 57D continue in this order from the outer periphery toward the inside (the center of the clad piece 31). It is preferable that the gradient of the inclined surfaces 57A to 57D of the convex-forming recess 56 of the punch 55B relative to the bottom surface 52 of the vertical hole 51 of the die 50 be smallest for the inclined surface 57A, and increase in the order of the inclined surface 57B, the inclined surface 57C, and the inclined surface 57D.

[0042] Note that inclined surfaces 57A, 57B, 57C, and 57D may each be flat or curved. For example, inclined surfaces 57A, 57B, 57C, and 57D may each be conical. In this case, when the taper angles of inclined surfaces 57A, 57B, 57C, and 57D are θ1, θ2, θ3, and θ4, respectively, it is preferable that θ1 > θ2 > θ3 > θ4.

[0043] 7 is a cross-sectional view showing the intermediate body 32 formed in step (B) using the die 50 and punch 55A shown in FIG. 5. The intermediate body 32 can also be formed using the die 50 shown in FIG. 5 and the punch 55B shown in FIG. 6. As shown in FIG. 7, the intermediate body 32 has a high ductility conductor layer 32A and a low ductility conductor layer 32B, and a convex portion 32C is provided in the center on the low ductility conductor layer 32B side. The position of the convex portion 32C on the low ductility conductor layer 32B side corresponds to the center of the clad piece 31 on the low ductility conductor layer 32B side.

[0044] When the thickness of the high ductility conductor layer 32A at the outer peripheral edge of the intermediate body 32 is TH and the thickness of the low ductility conductor layer 32B at the outer peripheral edge of the intermediate body 32 is TL, it is preferable to satisfy TL / (TH+TL)≦0.2, and it is more preferable to satisfy TL / (TH+TL)≦0.1. That is, in step (B), it is preferable to extend the convex portion 32C into the convex-forming recess portion 56 of the punch 55A until TL / (TH+TL)≦0.2 is satisfied, and it is more preferable to extend the convex portion 32C into the convex-forming recess portion 56 of the punch 55A until TL / (TH+TL)≦0.1 is satisfied.

[0045] (C) Step of forming a shaft portion by extending the protrusion portion. Figures 8 and 9 are cross-sectional views illustrating step (C) of forming a shaft portion 33C (see Figure 10) by extending the protrusion portion 32C. Figure 8 shows the state in which the intermediate body 32 is placed in the die 60 in step (C). As shown in Figure 8, in a vertical hole portion 61 of the die 60 that opens toward the upper side (Z1 side) of the die 60, the intermediate body 32 is placed so that the high ductility conductor layer 32A side thereof contacts the bottom surface 62 of the vertical hole portion 61. In addition, the side surface of the intermediate body 32 in the direction perpendicular to the Z1 and Z2 directions is close to the inner peripheral wall 63 of the vertical hole portion 61 of the die 60. As a result, the Z2-side surface of the high ductility conductor layer 32A and the side surface in the direction perpendicular to the Z1 and Z2 directions are constrained by the bottom surface 62 and inner peripheral wall 63 of the vertical hole portion 61 of the die 60.

[0046] Next, the protrusion 32C of the intermediate body 32 is stretched to form the shank 33C. Figure 9 shows the step (C) of stretching the protrusion 32C by pressing the outer periphery of the low ductility conductor layer 32B of the intermediate body 32 with a punch 65. As shown in Figure 9, the punch 65 presses the outer periphery of the low ductility conductor layer 32B of the intermediate body 32 from above (the Z1 side) the vertical hole 61 of the die 60. The punch 65 has a shank-forming recess 66 on its inner side (at the center of the clad piece 31) that opens downward (to the Z2 side) and extends upward (to the Z1 side). The shank-forming recess 66 may be configured as a hole that penetrates the punch 65 in the vertical direction (the Z1 and Z2 directions), or as a non-penetrating recess. By pressing the outer periphery of the low-ductility conductor layer 32B of the intermediate body 32 with the punch 65, the plastic deformation of the side surfaces of the clad piece 31 in the X1 and X2 directions is constrained by the inner peripheral wall 63 of the vertical hole 61 of the die 60, while the convex portion 32C of the intermediate body 32 is plastically deformed toward the Z1 side inside the shank-forming recess 66, thereby forming the shank 33C (see FIG. 10 ) inside the shank-forming recess 66. At this time, the stress acting on the central portion of the intermediate body 32 due to the pressing is smaller than that acting on the outer edge portion, so the low-ductility conductor layer 32B is more likely to plastically flow toward the center in the direction perpendicular to the thickness direction. This makes it possible to suppress the generation of burrs in the low-ductility conductor layer 32B.

[0047] 9 , the inner peripheral edge of the shank-forming recess 66 of the punch 65 is preferably provided with an inclined surface 67 that is inclined upward (toward the Z1 side) toward the inside (the center of the clad piece 31). The provision of the inclined surface 67 allows the low-ductility conductor layer 32B to more smoothly plastically flow upward (toward the Z1 side) within the shank-forming recess 66 along the inclined surface 67. Note that when pressing the intermediate body 32 with the punch 65, a guide 69 may be used to guide the punch 65 in the up-down direction (Z1 and Z2 directions).

[0048] (D) Step of forming an intermediate bottomed hole portion on one end side of the shank portion. Figure 10 is a cross-sectional view for explaining step (D) of forming an intermediate bottomed hole portion 34D (see Figure 11) on one end side of the shank portion 33C. Figure 10 shows the state in step (D) in which the intermediate body 33 formed in step (C) is placed in a die 70. As shown in Figure 10, the intermediate body 33 formed in step (C) is placed in a vertical hole portion 71 that opens toward the upper side (Z1 side) of the die 70, with the shank portion 33C facing upward (Z1 side) and the high ductility conductor layer 33A side contacting the bottom surface 72 of the vertical hole portion 71. In addition, the side surface of the intermediate body 33 perpendicular to the Z1 and Z2 directions is close to the inner peripheral wall 73 of the vertical hole portion 71 of the die 70. As a result, the Z2 side surface and the side surface perpendicular to the Z1 and Z2 directions of the highly ductile conductor layer 33A are constrained by the bottom surface 72 and inner peripheral wall 73 of the vertical hole portion 71 of the die 70.

[0049] 10, punch 75 having a substantially flat tip is lowered from above (Z1 side) to below (Z2 side) vertical hole 71 of die 70, and the tip of punch 75 presses against the tip of shank 33C. As a result, intermediate bottomed hole 34D (see FIG. 11) having the shape of the tip of punch 75 transferred thereto is formed in the tip of shank 33C.

[0050] (E) Step of forming a bottomed hole portion on one end side of the shaft portion Figure 11 is a cross-sectional view for explaining step (E) of forming a bottomed hole portion 35D (see Figure 12) on one end side (Z1 side) of the shaft portion 34C having the intermediate bottomed hole portion 34D of the intermediate body 34. As shown in Figure 11, in step (E), the intermediate body 34 obtained in step (D) is placed in a vertical hole portion 81 opening upward (Z1 side) of the die 80 so that the intermediate bottomed hole portion 34D of the intermediate body 34 faces upward (Z1 side) and the high ductility conductor layer 34A side contacts the bottom surface 82 of the vertical hole portion 81 of the die 80. In addition, the side surface of the intermediate body 34 perpendicular to the Z1 and Z2 directions is close to the inner peripheral wall 83 of the vertical hole portion 81 of the die 80. As a result, the Z2 side surface and the side surface perpendicular to the Z1 and Z2 directions of the highly ductile conductor layer 34A are constrained by the bottom surface 82 and inner peripheral wall 83 of the vertical hole portion 81 of the die 80.

[0051] 11, the punch 85 is lowered from above (Z1 side) to below (Z2 side) the vertical hole 81 of the die 80, and the tip of the punch 85 is inserted into the intermediate bottomed hole 34D, and the punch 85 is further lowered to press against the intermediate body 34. This forms a bottomed hole 35D (see FIG. 12) to which the shape of the tip of the punch 85 is transferred.

[0052] (F) Step of forming a flange by pressing the other end side of the shaft portion Figure 12 is a cross-sectional view for explaining step (F) of forming a flange by pressing the other end side (Z2 side) of the shaft portion 35C of the intermediate body 35. Note that the flange formed here is the original flange shape corresponding to the flange portion 20 shown in Figure 1. As shown in Figure 12, in step (F), the intermediate body 35 obtained in step (E) is placed on the upper surface 92 of the die 90. Specifically, the intermediate body 35 is placed on the upper surface 92 of the die 90 so that the bottomed hole portion 35D of the intermediate body 35 faces upward (Z1 side) and the high ductility conductor layer 35A side is in contact with the upper surface 92 of the die 90.

[0053] 12, the punch 95 is lowered from above (Z1 side) to below (Z2 side). At this time, the punch 95 is lowered toward the inclined surface on the Z1 side (the inclined surface on the outer periphery of the low-ductility conductor layer 35B) that is outer than the shank 35C of the intermediate body 35. By appropriately pressing the inclined surface on the Z1 side that is outer than the shank 35C of the intermediate body 35 with the die 90 and punch 95, the inclined surface on the outer periphery is plastically deformed toward the Z2 side, and a flange portion (original flange portion shape) is formed.

[0054] (G) Step of Trimming the Outermost Periphery of the Flange Next, as necessary, the outermost periphery of the flange (original flange shape) is trimmed from the intermediate (not shown) on which the flange (original flange shape) was formed in step (F). This completes the terminal component 1 having the shank 10 and flange 20 shown in Fig. 1. If the trimming is not performed, the flange (original flange shape) formed in step (F) becomes the flange 20 shown in Fig. 1.

[0055] As described above, in the manufacturing method of the terminal component 1 according to the embodiment of the manufacturing method of the terminal component for a battery of the present invention, in step (A), the clad plate 30 is punched in the thickness direction (Z1, Z2 directions) to form the clad piece 31. Then, in step (B), when the clad piece 31 formed in step (A) is placed in the lower mold (die 50), the clad piece 31 is placed so that the high ductility conductor layer 31A contacts the bottom surface 52 of the vertical hole portion 51 that opens upward (toward the Z1 side) in the lower mold (die 50), and when the upper mold (punch 55A) is inserted into the vertical hole portion 51 of the lower mold (die 50) to press the upper surface (toward the Z1 side) of the low ductility conductor layer 31B of the clad piece 31, in the upper mold (punch 55A), A convex portion forming recess 56 opens downward (toward the Z2 side) and extends upward (toward the Z1 side) to form a convex portion 32C that becomes an axis portion 33C at the center of the clad piece 31 in directions perpendicular to the thickness direction (X1, X2 direction and Y1, Y2 direction).The plastic deformation of the X-direction side surface of the clad piece 31 is restrained by the inner wall 53 of the vertical hole portion 51 of the lower mold (die 50), while the clad piece 31 is plastically deformed toward the convex portion forming recess 56, thereby forming the convex portion 32C inside the convex portion forming recess 56.

[0056] As a result, in step (B) of forming the convex portion 32C that becomes the shaft portion 33C from the clad piece 31, the side surface of the clad piece 31 in the direction perpendicular to the thickness direction is constrained by the inner peripheral wall 53 of the vertical hole 51, and pressing is performed from the low-ductility conductor layer 31B side with a punch 55A having a convex portion-forming recess 56 that opens downward (to the Z2 side), so that the stress acting on the central portion of the clad piece 31 due to the pressing is smaller than that on the outer edge portion, and the low-ductility conductor layer 31B is more likely to plastically flow toward the center. This prevents the low-ductility conductor layer 31B from penetrating between the die 50 and the punch 55A at the outer edge of the clad piece 31, and prevents burrs from occurring in the low-ductility conductor layer 31B between the die 50 and the punch 55A. In addition, since the high ductility conductor layer 31A is pressed from the low ductility conductor layer 31B side (Z1 side) while being restrained by the die 50, the high ductility conductor layer 31A is prevented from penetrating between the die 50 and the punch 55A at the outer edge of the clad piece 31, and the occurrence of burrs in the high ductility conductor layer 31A between the die 50 and the punch 55A is prevented.

[0057] The manufacturing method of the terminal component 1 according to the embodiment of the manufacturing method of the battery terminal component of the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications are possible within the scope of the gist of the above embodiment. For example, the step (E) of forming the bottomed hole portion 35D and the step (F) of forming the flange portion may be performed simultaneously.

[0058] The battery terminal component according to the present invention can be used by connecting it to an electrode of a lithium-ion secondary battery, for example. This application claims priority to Japanese Patent Application No. 2023-208590, filed December 11, 2023.

Claims

1. A method for manufacturing a terminal part for a battery, using a clad plate formed by stacking and bonding a high ductility conductor layer and a low ductility conductor layer having lower ductility than the high ductility conductor layer in the thickness direction, the terminal part having a shaft portion extending in the thickness direction of the clad plate and a flange portion extending from the shaft portion in a direction perpendicular to the thickness direction, the method comprising the steps of: (1) disposing a clad piece formed by punching the clad plate in the thickness direction in a lower die such that the high ductility conductor layer is in contact with a bottom surface of a vertical hole portion that opens upward in the lower die; a step (2) of plastically deforming the clad piece toward the convex portion-forming recess in the upper mold, the convex portion-forming recess in the upper mold opening downward and extending upward to form the convex portion that serves as the axis portion at the center of the clad piece in the orthogonal direction, while the plastic deformation of the side surface of the clad piece is restrained by the inner wall of the vertical hole of the lower mold, to form the convex portion inside the convex portion-forming recess when the upper mold is inserted into the vertical hole of the lower mold to press the upper surface of the low ductility conductor layer of the clad piece.

2. The method for manufacturing a terminal component as set forth in claim 1, wherein the inner peripheral edge of the inner peripheral wall of the convex portion forming recess of the upper mold is provided with an inclined surface that is inclined upward toward the center in the perpendicular direction.

3. A method for manufacturing a terminal component as described in claim 1 or 2, wherein the gradient of the inclined surface of the inner peripheral edge of the upper mold relative to the bottom surface of the vertical hole portion of the lower mold increases toward the center in the perpendicular direction.

4. A method for manufacturing a terminal part as described in any one of claims 1 to 3, wherein the upper mold has a plurality of flat or curved surfaces continuing from the outer periphery of the lower end toward the center in the orthogonal direction, and the gradient of the plurality of flat or curved surfaces relative to the bottom surface of the vertical hole portion of the lower mold increases toward the center in the orthogonal direction.

5. A method for manufacturing a terminal component as claimed in any one of claims 1 to 4, wherein the upper mold has a plurality of conical surfaces that are continuously inclined upward from the outer periphery of the lower end toward the center in the orthogonal direction, and the plurality of conical surfaces have a smaller taper angle toward the upper part.

6. A method for manufacturing a terminal component as described in any one of claims 1 to 5, wherein in step (2), the clad piece is extended into the interior of the convex portion-forming recess of the upper mold until TL / (TH+TL)≦0.2 is satisfied, where TH is the thickness of the high ductility conductor layer at the outer peripheral edge of the clad piece and TL is the thickness of the low ductility conductor layer.

7. A method for manufacturing a terminal component according to any one of claims 1 to 6, comprising, after step (2), a step (3) of extending the protrusion to form the shaft portion.

8. The method for manufacturing a terminal component according to claim 7, further comprising, after step (3), a step (4) of forming a bottomed hole portion on one end side of the shaft portion.

9. A method for manufacturing a terminal part as described in claim 8, comprising, after step (4), a step (5) of forming the flange portion extending radially from the shaft portion by pressing the other end side opposite to the one end side of the shaft portion.

10. The method for manufacturing a terminal component according to claim 9, further comprising a step (6) of trimming the outermost periphery of the flange portion after the step (5).

11. The method for manufacturing a terminal component according to claim 10, wherein steps (1) to (6) are carried out by transfer press molding.

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