KR20160048693A - Battery terminal, method for manufacturing battery terminal and battery - Google Patents

Abstract

A battery terminal includes a shaft portion and a flange portion. The battery terminal is formed of a clad material in which at least a first metal layer and a second metal layer are bonded to each other. Each of the shaft portion and the flange portion includes the first metal layer on one side in an axial direction and the second metal layer on the other side in the axial direction. The first metal layer in the shaft portion includes a protruding portion that further protrudes to the other side in the axial direction with respect to a surface of the first metal layer on the other side in the axial direction in the flange portion. Thus, bonding strength between different types of metal layers may be increased.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a battery terminal,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery terminal applicable to, for example, a lithium ion battery, a method of manufacturing the battery terminal, and a battery using the battery terminal, And a battery using the battery terminal.

Conventionally, for example, a battery terminal having another metal layer disclosed in Japanese Patent No. 5426594 is known.

Japanese Patent No. 5426594 discloses a negative electrode rivet (battery terminal) having a head portion made of Cu to which a current collecting plate made of Cu is joined and a tail portion made of Al to which a bus bar made of Al is joined. This negative electrode rivet is integrated (joined) by friction stir welding in a state in which the shaft portion of the head portion and the tail portion are arranged to face each other. As another example, Japanese Patent No. 5426594 discloses a negative electrode rivet (battery terminal) further provided with a bonding portion composed of a clad metal disposed between the shaft portion and the tail portion of the head portion and in which the Cu layer and the Al layer are pressure- . The negative electrode rivets of this other example are integrated (joined) by laser welding a head portion made of Cu, a Cu layer made of clad metal, a Te portion made of Al and an Al layer made of clad metal.

However, in the negative electrode rivet disclosed in Japanese Patent No. 5426594, when the head portion made of Cu and the tail portion made of Al are joined by friction stir welding or laser welding, the interface (joining portion) A large amount of heat is generated by light, and therefore, the temperature is high. At this time, since the heat reaches the interface between Cu of the head portion and Al of the tail portion, a weak intermetallic compound is generated, and thus the bonding strength between the head portion and the tail portion tends to decrease.

An object of the present invention is to solve the above problems in a battery terminal having another metal layer. One object of the present invention is to provide a battery terminal capable of increasing the bonding strength between different metal layers, A method of manufacturing a battery terminal, and a battery using the battery terminal.

A terminal for a battery according to a first aspect of the present invention is a terminal for a battery having a shaft portion and a flange portion having a radial extension radially from the shaft portion and the battery terminal is made of a clad material having at least a first metal layer and a second metal layer joined together Wherein each of the shaft portion and the flange portion is constituted by a first metal layer on one side in the axial direction of the shaft portion and a second metal layer on the other side, The metal layer has a portion projecting to the other side in the axial direction than the surface on the other side in the axial direction.

In the battery terminal according to the first aspect of the present invention, as described above, since it is composed of the clad material, it is not necessary to apply excessive heat to the intermetallic compound when the battery terminal is manufactured. Therefore, The lowering of the bonding strength between the first metal layer and the second metal layer can be prevented as compared with the case where the first metal layer and the second metal layer are bonded by welding. Further, since the first metal layer of the shaft portion has a portion protruding to the other side in the axial direction from the surface on the other side in the axial direction in the first metal layer of the flange portion, the protruded portion is formed, 2 metal layer can be increased, so that the bonding strength between the first metal layer and the second metal layer can be increased.

In the battery terminal according to the first aspect of the present invention, as described above, each of the shaft portion and the flange portion is constituted by the first metal layer on one side in the axial direction of the shaft portion and the second metal layer on the other side . As a result, the first metal layer on one side in the axial direction of the shaft portion can be easily joined to the connection member for connecting the batteries to each other or the current collector of the battery, and the second metal layer on the other side in the axial direction of the shaft portion The connecting member or the other side of the current collector can be easily joined. As a result, the connecting member and the current collector can be easily electrically connected through the battery terminal. When the connecting member and the current collector are made of different metals, one of the first metal layer and the connecting member or the current collector is made of the same kind of metal, and the other of the second metal layer and the connecting member or the current collector is made of The connecting member and the current collector can be electrically connected to each other through the battery terminal in a state in which the same type of metal is used to secure a firm connection by bonding of the same kind of metal.

In the battery terminal according to the first aspect, it is preferable that the protruding portion of the first metal layer is formed so as to have an axis more radially inward than the surface on the other side in the axial direction of the first metal layer of the flange portion, As shown in Fig. With this configuration, the interface area between the first metal layer and the second metal layer can be increased at the central portion of the shaft portion near the center of the battery terminal, so that the bonding strength between the first metal layer and the second metal layer is effectively increased .

In this case, preferably, the protruding portion of the first metal layer has a convex portion protruding in a convex shape toward the other side in the axial direction at the central portion of the shaft portion. With this configuration, since the interface area between the first metal layer and the second metal layer can be surely increased by forming the convex portion, the bonding strength between the first metal layer and the second metal layer can be reliably increased.

In the configuration in which the protruded portion has a convex portion, preferably, on the axial center of the shaft portion, the convex portion protrudes from the other side in the axial direction of the flange portion to the other side in the axial direction. With this configuration, the interface area between the first metal layer and the second metal layer can be increased as compared with the case where the convex portion does not protrude to the other side in the axial direction of the flange portion from the other side in the axial direction, The bonding strength between the first metal layer and the second metal layer can be increased. When the first metal layer and the connecting member or the current collector are bonded to each other at the shaft portion, the interface (the other end in the axial direction of the convex portion) between the first metal layer and the second metal layer at the shaft portion is exposed As shown in Fig. As a result, the interface between the first metal layer and the second metal layer at the shaft portion is largely spaced apart from the exposed first metal layer and the connection portion between the connection member and the current collector, so that heat due to the bonding (welding) It is possible to suppress reaching the interface. As a result, generation of a weak intermetallic compound at the interface between the first metal layer and the second metal layer can be suppressed, so that the lowering of the bonding strength between the first metal layer and the second metal layer can be suppressed.

It is preferable that the convex portion is provided on the other side in the axial direction with respect to the surface on the other side in the axial direction of the flange portion on the axial center of the flange portion, As shown in Fig. With this configuration, since the convex portion is formed relatively large, the interface area between the first metal layer and the second metal layer can be increased.

In the battery terminal according to the first aspect, preferably, one of the first metal layer and the second metal layer is made of Al or an Al alloy (Al-based alloy), and the other of the first metal layer or the second metal layer Is made of Cu or a Cu alloy (Cu-based alloy). According to this configuration, the first metal layer on one side in the axial direction of the battery terminal is made of the same metal (Al-based alloy or Cu-based alloy) as one of the connection member or the current collector, Is formed of a metal (Cu-based alloy or Al-based alloy) similar to the other of the connecting member or the current collector, the connecting member, the battery terminal and the current collector are bonded to each other in a rigid bonding state It is possible to electrically connect with each other. Further, the Al-based alloy and the Cu-based alloy are all relatively easily deformed to a great degree of flexibility, so that it is possible to suppress breakage or the like from occurring when one of the first metal layer and the second metal layer is relatively less ductile It is possible to easily form the convex portion in the first metal layer.

In the battery terminal according to the first aspect, preferably, the minimum length of the first metal layer in the flange portion in the axial direction is 30% or more of the length of the flange portion. According to this configuration, since the first metal layer can be sufficiently secured in the axial direction in the flange portion, when the first metal layer exposed on one side in the axial direction of the battery terminal is joined to the connection member or the current collector, It is possible to suppress the heat due to the bonding (welding) with the connecting member or the current collector from reaching the interface between the first metal layer and the second metal layer.

The length from the surface on the other side in the axial direction of the flange portion to the end on the other side in the axial direction of the convex portion on the axial center of the flange portion preferably has a length 80% or less. With this configuration, the axial length of the second metal layer can be easily secured on the other side in the axial direction of the shaft portion. Thereby, when joining the second metal layer on the other axial side of the shaft portion to the connection member or the current collector, the axial length of the second metal layer is ensured and the second metal layer and the connection member or the current collector can be easily bonded . In addition, by ensuring the length in the axial direction of the second metal layer, when the end on the other side in the axial direction of the shaft portion is joined to the connecting member or the current collector, the interface between the first metal layer and the second metal layer Direction from the other end in the axial direction in which the second metal layer is exposed. As a result, the interface between the first metal layer and the second metal layer is largely spaced from the junction between the second metal layer and the connection member or the current collector, so that heat due to bonding (welding) of the junction is prevented from reaching the interface . As a result, generation of a weak intermetallic compound at the interface between the first metal layer and the second metal layer can be suppressed, so that the lowering of the bonding strength between the first metal layer and the second metal layer can be suppressed.

In the terminal for a battery according to the first aspect, preferably, a bottomed hole having a bottom surface and an inner surface made of a second metal layer is formed at the other end in the axial direction of the shaft portion. With this configuration, when the battery terminal is fixed to the connection member or the current collector, for example, the connection member or the current collector is fixed in the hole of the hole having the bottom, The battery terminal and the connecting member or the current collector can be easily fixed by deforming the metal layer by a caulking or the like.

In the battery terminal according to the first aspect, preferably, the first metal layer and the second metal layer are all formed axially symmetrically with respect to the axial center of the shaft portion. With this configuration, the battery terminal having a relatively simple shape can be easily formed.

The battery terminal according to the first aspect preferably further includes a reaction inhibiting layer for suppressing the reaction of the metal constituting the first metal layer and the metal constituting the second metal layer. With this configuration, since the reaction inhibiting layer can reliably suppress the formation of a weak intermetallic compound by the reaction of the metal constituting the first metal layer and the metal constituting the second metal layer, the first metal layer and the second metal layer The lowering of the bonding strength due to the intermetallic compound with the metal layer can be reliably suppressed.

The projected portion of the first metal layer protrudes from the center portion of the shaft portion. Preferably, in the protruding portion of the first metal layer, the portion of the first metal layer, which is located outside the center portion, As shown in Fig. With this configuration, the bonding strength between the first metal layer and the second metal layer at the position where the outer portion is formed can be effectively increased.

In this case, preferably, the outer portion is annularly protruded toward the other side in the axial direction. With this configuration, it is possible to effectively prevent slippage in the direction perpendicular to the axial direction at the interface between the first metal layer and the second metal layer by the annularly protruding outer portion.

The outer side portion is annularly protruded toward the other side in the axial direction. Preferably, the outer side portion is annularly protruded toward the other side in the axial direction. With this configuration, it is possible to easily secure both the improvement of the bonding strength and the suppression of the occurrence of slippage without forming the outer portion as a complicated shape.

A method of manufacturing a terminal for a battery according to a second aspect of the present invention includes the steps of forming an overlay clad material by joining at least a first metal layer and a second metal layer, And a flange portion having a radial extension from the shaft portion in the radial direction and each of the shaft portion and the flange portion has a first metal layer on one side in the axial direction of the shaft portion and a second metal layer on the other side, And a step of forming the battery terminal so that the first metal layer at the shaft portion has a portion protruding to the other side in the axial direction from the surface on the other side in the axial direction of the first metal layer in the flange portion.

In the method for manufacturing a battery terminal according to the second aspect of the present invention, in addition to the effect of the first aspect, the overlay type clad material is subjected to extrusion processing by relatively simple positioning, It is possible to produce a battery terminal in which a protruded portion is formed in one metal layer.

In the method of manufacturing a terminal for a battery according to the second aspect, preferably, the step of forming an overlay clad material is a step of forming a clad member by repeating a step of: And bonding the reaction inhibiting layer between the first metal layer and the second metal layer. With this configuration, since the reaction inhibiting layer can reliably suppress the formation of a weak intermetallic compound by the reaction of the metal constituting the first metal layer and the metal constituting the second metal layer, the first metal layer and the second metal layer The lowering of the bonding strength due to the intermetallic compound with the metal layer can be reliably suppressed.

A battery according to a third aspect of the present invention includes a terminal for a battery having a shaft portion and a flange portion having a radial extension radially from the shaft portion and the battery terminal includes at least a clad having a first metal layer and a second metal layer joined together, Wherein each of the shaft portion and the flange portion is constituted by a first metal layer on one side in the axial direction of the shaft portion and a second metal layer on the other side, The metal layer has a portion protruding toward the other side in the axial direction than the surface on the other side in the axial direction.

In the battery according to the third aspect of the present invention, the connection terminal for connecting the batteries to each other by the battery terminal to which the other metal layer of the first aspect is bonded and the collector of the battery made of the metal different from the connection member .

In the battery according to the third aspect, preferably, the protruding portion of the first metal layer of the battery terminal is located at least in the central portion of the shaft portion, And protrudes to the other side in the axial direction. With this configuration, the interface area between the first metal layer and the second metal layer can be increased at the central portion of the shaft portion near the center of the battery terminal, so that the junction between the first metal layer and the second metal layer The strength can be effectively increased.

In this case, preferably, the protruding portion of the first metal layer of the battery terminal has a convex portion protruding in a convex shape on the other side in the axial direction at the central portion of the shaft portion. With this configuration, since the convex portion is formed on the battery terminal, the interface area between the first metal layer and the second metal layer can be surely increased, so that the bonding strength between the first metal layer and the second metal layer can be surely increased .

In the battery according to the third aspect, preferably, the first metal layer of the battery terminal is connected to one of the connection members or the current collector made of the same metal as the first metal layer, and the second metal layer of the battery terminal, And is connected to the connection member made of the same kind of metal as the second metal layer or the other side of the current collector. With this configuration, the connecting member and the current collector can be electrically connected to each other through the battery terminal in a state in which a firm bonding is secured by bonding of the same kind of metal.

1 is a perspective view showing a battery module according to a first embodiment of the present invention.
2 is a perspective view showing the entire structure of a lithium ion battery according to the first embodiment of the present invention.
3 is an exploded perspective view showing the entire structure of a lithium ion battery according to the first embodiment of the present invention.
4 is a cross-sectional view showing the periphery of a negative electrode terminal of a lithium ion battery according to the first embodiment of the present invention.
5 is a cross-sectional view showing a negative terminal of a lithium ion battery according to a first embodiment of the present invention.
6 is a perspective view for explaining a method of manufacturing a negative electrode terminal according to the first embodiment of the present invention.
7 is a perspective view for explaining a method of manufacturing a negative electrode terminal according to the first embodiment of the present invention.
8 is a cross-sectional view showing a periphery of a negative electrode terminal according to a second embodiment of the present invention.
9 is a cross-sectional view showing a negative electrode terminal according to a second embodiment of the present invention.
10 is a cross-sectional view showing a negative electrode terminal according to a third embodiment of the present invention.
11 is a cross-sectional view showing a negative terminal according to a fourth embodiment of the present invention.
12 is a perspective view showing a negative terminal according to a modification of the first embodiment of the present invention.
13 is a cross-sectional view showing a negative terminal according to a modification of the second embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First Embodiment)

First, the structure of the battery module 100 according to the first embodiment of the present invention will be described with reference to Figs. 1 to 5. Fig.

The battery module 100 according to the first embodiment of the present invention is a large-sized battery system used in an electric vehicle (EV), a hybrid electric vehicle (HEV), a housing storage system, and the like. 1, a plurality of lithium ion batteries 1 are electrically connected to each other by a plurality of plate-shaped bus bars 101 (shown by dotted lines) . The bus bar 101 is an example of the " joining member " of the present invention.

Further, in the assembled battery 100, a plurality of lithium ion batteries 1 are arranged so as to be arranged in the narrower direction (X direction) of the lithium ion battery 1 in plan view. In addition, in the assembled battery 100, the positive electrode terminal 10 is located on one side (Y1 side) in the wide direction (Y direction) orthogonal to the narrow direction and the positive electrode terminal 10 is disposed on the other side The lithium ion battery 1 (1a) in which the terminal 20 is located and the positive electrode terminal 10 is located on the Y2 side and the negative electrode terminal 20 is located on the Y1 side, ) Are arranged alternately along the X direction.

The positive electrode terminal 10 of the predetermined lithium ion battery 1 is welded to one end of the bus bar 101 made of Al extending in the X direction in the X direction. The negative electrode terminal 20 of the lithium ion battery 1 adjacent to the predetermined lithium ion battery 1 is welded to the other end of the bus bar 101 made of Al in the X direction. The positive electrode terminal 10 of the lithium ion battery 1 is connected to the negative electrode terminal 20 of the adjacent lithium ion battery 1 through the bus bar 101. [ In this way, a battery module 100 in which a plurality of lithium ion batteries 1 are connected in series is constructed. The use of the bus bar 101 made of Al makes it possible to reduce the weight of the bus bar 101 as compared with the case of using the bus bar made of Cu, 100 can be made lighter. In addition, Al means so-called pure Al of the A1000 range specified in the JIS standard, and Cu means so-called pure Cu such as oxygen-free copper, toughpitch copper, and phosphoric acid copper.

As shown in Fig. 2, the lithium ion battery 1 has a substantially rectangular parallelepiped-like appearance. The lithium ion battery 1 further includes a lid member 2 disposed on one side (upper side, Z1 side) of the vertical direction (Z direction) orthogonal to the X direction and the Y direction and a lid member 2 disposed on the other side And the battery case main body 3 disposed in the battery case 3. The lid member 2 and the battery case body 3 are all made of Ni-plated steel sheet.

As shown in Fig. 3, the lid member 2 is formed into a flat plate shape. A pair of insertion holes 2a and 2b are formed in the lid member 2 so as to penetrate in the Z direction. The pair of insertion holes 2a and 2b are formed at a predetermined distance in the Y direction of the lid member 2 and at substantially the center of the lid member 2 in the X direction. The positive electrode terminal 10 and the negative electrode terminal 20 are inserted into the pair of insertion holes 2a and 2b, respectively.

The lithium ion battery 1 also includes a power generation element 4 in which a positive electrode 4a, a negative electrode 4b and a separator 4c are stacked in a roll shape and an electrolyte solution not shown. The positive electrode 4a is composed of an Al foil coated with a positive electrode active material. The negative electrode 4b is composed of a Cu foil coated with a negative electrode active material. The separator 4c has a function of insulating the positive electrode 4a from the negative electrode 4b.

 The lithium ion battery 1 further includes a positive electrode collector 5 for electrically connecting the positive electrode terminal 10 and the positive electrode 4a of the power generation element 4 and a positive electrode collector 5 for electrically connecting the negative electrode terminal 20 and the power generation element 4 And a negative electrode collector 6 for electrically connecting the negative electrode 4b. The positive electrode current collector 5 is disposed on the Y1 side so as to correspond to the positive electrode terminal 10. The positive electrode current collector 5 has a connecting portion 5a in which a hole portion 5d into which the positive electrode terminal 10 is inserted is formed, a leg portion 5b extending to the Z2 side, a leg portion 5b and a positive electrode 4a (Not shown). The positive electrode current collector 5 is made of Al similarly to the positive electrode 4a.

The negative electrode collector 6 is disposed on the Y2 side so as to correspond to the negative electrode terminal 20. [ The negative electrode current collector 6 has a connecting portion 6a in which a hole portion 6d for inserting the negative electrode terminal 20 is formed, a leg portion 6b extending to the Z2 side, a leg portion 6b and a negative electrode 4b (Not shown). The negative electrode collector 6 is made of Cu like the negative electrode 4b.

The positive electrode terminal 10 includes a cylindrical shaft portion 11 extending in the Z direction and a cylindrical portion 11 extending radially from the shaft portion 11 in the XY plane direction at an end portion of the shaft portion 11 on the Z1 side and its periphery. And has an annular flange portion 12 formed therein. As a result, the positive electrode terminal 10 is formed in a rivet shape and has a T-shaped cross section along the Z direction.

The rivet-shaped positive electrode terminal 10 is made of Al, like the positive electrode collector 5 and the bus bar 101. In the positive electrode terminal 10, the unshown Al plate is subjected to extrusion molding so that the shaft portion 11 and the flange portion 12 are integrally formed.

A packing 7 having an insulating property is disposed between the flange portion 12 of the positive electrode terminal 10 and the lid member 2 and the connection 7 between the lid member 2 and the positive electrode collector 5 (5), a packing (8) having an insulating property is disposed. The packings 7 and 8 each have insertion holes 7a and 8a through which the shaft portion 11 of the positive electrode terminal 10 is inserted. The flange portion 12 of the positive electrode terminal 10 is disposed on the upper side of the lid member 2 so as to be disposed outside the lithium ion battery 1. On the other hand, a portion of the shaft portion 11 protruding to the Z2 side with respect to the flange portion 12 is disposed inside the insertion holes 7a, 2a and 8a and the lithium ion battery 1 (battery case main body 3) have.

The negative electrode terminal 20 has an outer shape similar to that of the positive electrode terminal 10. That is, the negative electrode terminal 20 includes a cylindrical shaft portion 21 extending in the Z direction, and a radially extending portion extending from the shaft portion 21 in the XY plane direction at the Z1 side end portion of the shaft portion 21 and its periphery. And an annular flange portion 22 formed to have an annular shape. As a result, as shown in Figs. 4 and 5, the negative electrode terminal 20 is formed in a rivet shape, and a cross section along the Z direction is formed in a T shape. Further, the shaft portion 21 is configured to be positioned substantially in the center of the negative electrode terminal 20 in the X and Y directions. The negative electrode terminal 20 is an example of the " battery terminal " of the present invention. The Z direction is an example of the "axial direction" of the present invention, the Z1 side is an example of the "one side in the axial direction" of the present invention, and the XY plane direction is an example of the "radial direction" of the present invention.

In the negative electrode terminal 20, the shaft portion 21 and the flange portion 22 are integrally formed by performing the extrusion molding described later. 5, the negative electrode terminal 20 has a diameter D1 of about 10 mm in the X and Y directions and a length L1 of about 12 mm in the Z direction. The flange portion 22 has a thickness t1 of about 2 mm in the Z direction. The Z2 side is an example of the "other side in the axial direction" of the present invention.

Here, in the first embodiment, as shown in Figs. 4 and 5, the negative electrode terminal 20 is formed of a first metal layer 30 made of Al which is relatively easily deformed and has a relatively large ductility And a second metal layer 40 made of easy Cu is composed of a clad material joined by rolling. The first metal layer 30 and the second metal layer 40 which are rolled and bonded to each other are firmly bonded at the interface I thereof. The first metal layer 30 is disposed on the upper portion of the shaft portion 21 and the flange portion 22 in the section along the Z direction (Z2 side) of the negative electrode terminal 20. As a result, The upper surface 22a of the flange portion 22 and the upper surface 22b of the flange portion 22 on the Z1 side of the negative electrode terminal 20 on the upper surface 21a of the shaft portion 21, (The side surface 22d in Fig.

In the first embodiment, the central portion 31 of the first metal layer 30 in the shaft portion 21 is formed with a convex portion 32 protruding toward the Z2 side in the Z direction (axial direction). That is, the first metal layer 30 of the shaft portion 21 has a portion (convex portion 32) protruding toward the Z2 side in the Z direction (axial direction) in the center portion 31 of the shaft portion 21. [ The end portion 32a of the convex portion 32 on the Z2 side of the shaft portion 21 is formed so as to have a tapered end.

The convex portion 32 is larger than the length (thickness t1) of the flange portion 22 in the Z direction on the Z2 side of the Z2 side of the flange portion 22 on the axis A of the shaft portion 21 Respectively. That is, the convex portion 32 of the first metal layer 30 in the shaft portion 21 protrudes toward the Z2 side of the surface (interface I) on the Z2 side of the first metal layer 30 of the flange portion 22 . On the other hand, on the axis A, the length L2 from the lower surface 22e of the flange portion 22 on the Z2 side to the end portion 32a on the Z2 side of the convex portion 32 is larger than the length L2 of the shaft portion 21 The negative electrode terminal 20 is formed so that the length L1 is 80% or less of the length L1. The maximum length L3 of the first metal layer 30 in the Z direction in the shaft portion 21 is about 90% or less of the length L1 along the Z direction of the negative electrode terminal 20 in the axis A, The negative electrode terminal 20 is formed. The length L3 is preferably about 80% or less of the length L1, and more preferably about 70% or less.

The second metal layer 40 is disposed so as to cover the first metal layer 30 from the Z2 side so that the Z2 side of the shaft portion 21 and the lower surface 22c of the flange portion 22 22 on the side surface 22d). As a result, the first metal layer 30 is prevented from being exposed on the Z2 side of the shaft portion 21 and the flange portion 22, so that the protrusion 32 is not exposed to the outside of the negative electrode terminal 20. [ Respectively.

In the annular flange portion 22, the first metal layer 30 and the second metal layer 40 are joined in the Z direction on the entire opposite surface. That is, in the flange portion 22, overlay type clad joining is performed. As a result, the interface I between the first metal layer 30 and the second metal layer 40 is formed so as to be exposed at the side surface 22d of the flange portion 22, not at the side surface of the shaft portion 21. [ Thereby, since the interface I is not disposed inside the lithium ion battery 1, it is possible to suppress the electrolytic solution or the like in the lithium ion battery 1 from reaching the interface I. As a result, it is possible to inhibit the bonding strength between the first metal layer 30 and the second metal layer 40 from becoming small due to the electrolyte or the like in the lithium ion battery 1.

The first metal layer 30 and the second metal layer 40 are all formed so as to be axially symmetric with respect to the axis A,

In the flange portion 22, the minimum thickness t2 of the first metal layer 30 in the Z direction is formed to be about 30% or more of the thickness t1 of the flange portion 22 in the Z direction. Here, the minimum thickness t2 means the thickness from the end surface of the interface I between the first metal layer 30 and the second metal layer 40 to the top surface 22a.

In the cross section along the Z direction of the shaft portion 21, the length (width) L4 along the X direction and the Y direction orthogonal to the Z direction of the convex portion 32 of the first metal layer 30 corresponds to the convex portion 32 and the length L5 of the second metal layer 40 along the X-direction and the Y-direction. It is preferable that the length L4 is formed to be twice or more the length L5. Here, the lengths L4 and L5 indicate the respective lengths of the first metal layer 30 in the X direction and the Y direction in the shaft portion 21 at the maximum position.

4, the bus bar 101 is laser-welded to the substantially central portion of the upper surface 21a (Z1 side surface) of the shaft portion 21 so that the upper surface 21a of the shaft portion 21 And a welded portion W1 is formed at approximately the center. The outer peripheral portion of the lower end 21b of the shaft portion 21 and the connecting portion 6a of the negative electrode collector 6 are laser welded so that the end portion 21b of the shaft portion 21 and the periphery thereof are welded Respectively.

A packing 7 having an insulating property is disposed between the flange portion 22 of the negative electrode terminal 20 and the lid member 2 in the same manner as the positive electrode terminal 10 side, And the connecting portion 6a of the negative electrode current collector 6, a packing 8 having an insulating property is disposed. The packings 7 and 8 each have insertion holes 7b and 8b into which the shaft portion 21 of the negative electrode terminal 20 is inserted. The flange portion 22 of the negative electrode terminal 20 is disposed on the upper side of the lid member 2 so as to be disposed outside the lithium ion battery 1. On the other hand, the portion of the flange portion 22 protruding from the flange portion 22 toward the Z2 side is disposed inside the insertion holes 7b, 2b and 8b and the lithium ion battery 1 (battery case main body 3) have.

In the first embodiment, the following effects can be obtained.

Since the first metal layer 30 and the second metal layer 40 are firmly bonded to each other at the interface I by forming the negative electrode terminal 20 of the clad material as described above in the first embodiment, The lowering of the bonding strength can be prevented as compared with the case where the first metal layer 30 and the second metal layer 40 are bonded by friction stir welding or laser welding which is easy to generate an intermetallic compound. The first metal layer 30 of the flange portion 22 is projected toward the Z2 side in the Z direction (axial direction) relative to the Z2 side surface (interface I) of the first metal layer 30 of the flange portion 22 The area of the interface I can be increased by forming the convex portion 32 so that the bonding strength between the first metal layer 30 and the second metal layer 40 is increased can do.

(Convex portion 32) protruding toward the Z2 side is formed in the central portion 31 of the shaft portion 21 in the center portion of the shaft portion 21 near the center of the negative electrode terminal 20 31 can increase the area of the interface I between the first metal layer 30 and the second metal layer 40 so that the bonding strength between the first metal layer 30 and the second metal layer 40 can be effectively increased can do.

The central portion 31 of the first metal layer 30 in the shaft portion 21 has the convex portion 32 protruded toward the Z2 side so that the convex portion 32 is formed so that the interface I The bonding strength between the first metal layer 30 and the second metal layer 40 can be reliably increased.

In the first embodiment, each of the shaft portion 21 and the flange portion 22 is constituted by the first metal layer 30 on the Z1 side and the second metal layer 40 on the Z2 side. As a result, the first metal layer 30 exposed on the Z1 side of the negative electrode terminal 20 and the bus bar 101 connecting the lithium ion batteries 1 can be easily joined together and the negative electrode terminal 20 The negative electrode current collector 6 of the lithium ion battery 1 can be easily joined to the second metal layer 40 exposed on the Z2 side of the lithium ion battery 1. [ As a result, the bus bar 101 and the negative electrode collector 6 can be easily electrically connected through the negative electrode terminal 20. The first metal layer 30 is made of the same metal as the bus bar 101 and the second metal layer 40 is made of the same metal Cu as the negative electrode collector 6, The bus bar 101 and the negative electrode collector 6 can be electrically connected to each other through the negative electrode terminal 20 in a state in which a firm connection is ensured by the joining of the bus bar 101 and the negative electrode terminal 20. [

In the first embodiment, the convex portion 32 protrudes toward the Z2 side from the Z2 side lower surface 22e of the flange portion 22 on the axis A of the shaft portion 21, The area of the interface I between the first metal layer 30 and the second metal layer 40 can be increased as compared with the case where the first metal layer 30 and the second metal layer 40 do not protrude to the Z2 side ) Can be increased. The interface I between the first metal layer 30 and the second metal layer 40 in the shaft portion 21 is defined as the first interface layer I between the first metal layer 30 and the bus bar 101 in the shaft portion 21, The metal layer 30 can be largely separated from the upper surface 21a on the Z1 side of the exposed negative electrode terminal 20. [ As a result, the interface I of the shaft portion 21 is largely separated from the exposed portion of the first metal layer 30 and the bus bar 101 (welded portion W1), so that the first metal layer 30 and the bus bar 101, It is possible to inhibit the heat due to the bonding (welding) to the interface I from reaching the interface I. As a result, the generation of the weak intermetallic compound at the interface I can be suppressed, so that the lowering of the bonding strength between the first metal layer 30 and the second metal layer 40 can be suppressed.

In the first embodiment, the first metal layer 30 is made of the same Al as that of the bus bar 101, and the second metal layer 40 is made of the same Cu as the negative electrode collector 6, 101, the negative electrode terminal 20, and the negative electrode collector 6 can be electrically connected to each other in a state of a solid bonding state by the same metal. Al and Cu are both relatively soft and easily deformed and have the same degree of ductility so that the convex portion 32 is easily formed in the first metal layer 30 while suppressing the occurrence of breakage or the like can do.

In the first embodiment, the convex portion 32 is formed so as to be closer to the Z2 side than the Z2 side lower surface 22e of the flange portion 22 on the axis A of the shaft portion 21, (Thickness t1). As a result, since the convex portion 32 can be formed sufficiently large, the area of the interface I between the first metal layer 30 and the second metal layer 40 can be increased.

In the first embodiment, in the flange portion 22, the minimum thickness t2 of the first metal layer 30 in the Z direction is formed to be about 30% or more of the thickness t1 of the flange portion 22 in the Z direction do. The first metal layer 30 exposed on the Z1 side of the negative electrode terminal 20 and the bus bar 101 exposed on the Z1 side can be provided in the flange portion 22 It is possible to prevent the heat due to the bonding (welding) between the first metal layer 30 and the bus bar 101 from reaching the interface I at the time of bonding.

In the first embodiment, the length L2 from the lower surface 22e of the flange portion 22 on the Z2 side to the end portion 32a on the Z2 side of the convex portion 32 is set to be smaller than the length L2 on the shaft portion 21 Of the length L1 of the negative electrode terminal 20). As a result, the length along the Z direction of the second metal layer 40 on the Z2 side of the shaft portion 21 can be easily secured. As a result, when joining the second metal layer 40 on the Z2 side of the shaft portion 21 and the negative electrode collector 6, the length of the second metal layer 40 in the Z direction is secured and the second metal layer 40 The negative electrode current collector 6 can be easily joined.

In the first embodiment, when the end portion 21b on the Z2 side of the shaft portion 21 and the negative electrode current collector 6 are joined to each other by securing the length of the second metal layer 40 in the Z direction, The interface I (the end portion 32a on the Z2 side of the convex portion 32) between the first metal layer 30 and the second metal layer 40 is made to be spaced apart from the Z2 side end portion 21b on which the second metal layer 40 is exposed . As a result, the interface I is largely separated from the bonding portion (weld portion W2) between the second metal layer 40 and the negative electrode collector 6, so that heat due to the welding (welding) of the weld portion W2 is prevented from reaching the interface I . As a result, the generation of the weak intermetallic compound at the interface I can be suppressed, so that the lowering of the bonding strength between the first metal layer 30 and the second metal layer 40 can be suppressed.

In the first embodiment, both the first metal layer 30 and the second metal layer 40 are formed so as to be substantially axisymmetric with respect to the axis A, so that the negative electrode terminal 20 having a relatively simple shape can be easily .

In the first embodiment, the negative electrode terminal 20, to which the other metal layer (the first metal layer 30 and the second metal layer 40) are bonded, forms a bus bar 101 connecting the lithium ion batteries 1 And the negative electrode current collector 6 of the lithium ion battery 1 made of a metal different from that of the bus bar 101 can be easily joined.

Next, a manufacturing process of the lithium ion battery 1 and the assembled battery 100 according to the first embodiment of the present invention will be described with reference to Figs. 1 to 7. Fig.

First, a roll-shaped Al plate (not shown) having a predetermined thickness and a roll-shaped Cu plate (not shown) having a predetermined thickness are prepared. The ratio of the thickness t2 of the first metal layer 30 to the thickness t1-t2 of the second metal layer 40 in the flange portion 22 of the negative electrode terminal 20 (see Fig. 4) t2: (t1-t2), see Fig. 5]. For example, both the thickness of the Al plate and the thickness of the Cu plate are adjusted to about 4 mm. Further, the width of the Al plate and the width of the Cu plate are made substantially equal.

Then, a roll-shaped Cu plate is laminated on the entire surface of one surface of the roll-shaped Al plate in the Z-direction, and the Al plate and the Cu plate are successively subjected to pressure contact welding at a predetermined reduction rate (for example, about 50% do. Thereafter, the bonded Al and Cu plates are held at a temperature of about 500 DEG C for 1 minute to perform diffusion annealing on the bonded Al and Cu plates. Thus, a roll-shaped clad material having a thickness of about 4 mm is formed. Then, this clad material is punched into a disc shape having a diameter of about 10 mm, whereby a disc-shaped clad material 120 as shown in Fig. 6 is formed. The disk-shaped clad material 120 has a first metal layer 30 made of Al on one side (upper side, Z1 side) in the Z direction and a second metal layer 30 made of Al on the other side (lower side and Z2 side) Called overlay type clad material 120 in which the first metal layer 30 and the second metal layer 40 are joined in the Z direction with the metal layer 40 disposed therebetween.

6, an overlay type clad material 120 (see FIG. 5) is formed in a mold 102 having a form corresponding to the shape of the negative electrode terminal 20 (see FIG. 5) ). Then, the overlay type clad material 120 is subjected to extrusion processing at room temperature. Specifically, the clad material 120 is pressed from the first metal layer 30 side (upper side, Z1 side) of the clad material 120 by a predetermined pressing pressure to the clad material 120 by using a servo press machine 103 capable of controlling the press- Apply pressure. 7, the central portions of the clad material 120 in the X direction and the Y direction are pushed toward the lower portion corresponding to the shaft portion 21 of the mold 102. As shown in Fig.

As a result, as shown in Fig. 5, a negative terminal 20 having a cylindrical shaft portion 21 and an annular flange portion 22 and a T-shaped cross section along the Z direction is formed. A convex portion 32 protruding toward the Z2 side is formed in the center portion 31 of the first metal layer 30 in the shaft portion 21. [ At this time, in the annular flange portion 22, an overlay type clad junction is formed in which the first metal layer 30 and the second metal layer 40 are bonded to each other in the entire region where the first metal layer 30 and the second metal layer 40 face each other. In addition, by performing this extrusion processing a plurality of times, the dimensional accuracy and the like of the outer shape of the negative electrode terminal 20 may be improved.

4, the shaft portion 21 on the Z2 side of the flange portion 22 of the negative electrode terminal 20 is inserted into the insertion hole 7b of the packing 7 and the insertion hole 7b of the lid member 2 The end portion 21b of the shaft portion 21 of the negative electrode terminal 20 and the connecting portion 6a of the negative electrode current collector 6 are inserted into the insertion hole 8b of the packing 8 (Not shown) by laser welding. At this time, laser light is irradiated (scanned) along the circumference of the cylindrical shaft portion 21. Thereby, the negative electrode terminal 20 and the negative electrode collector 6 are joined (welded). At this time, since the second metal layer 40 and the negative electrode collector 6 located at the welded portion W2 of the shaft portion 21 of the negative electrode terminal 20 are all made of Cu, they are firmly welded (welded). Further, since the interface I is largely spaced apart from the bonding portion (weld portion W2) between the second metal layer 40 and the negative electrode collector 6, the heat due to the welding (welding) of the weld portion W2 is suppressed from reaching the interface I do.

3, the portion protruding from the flange portion 12 of the shaft portion 11 of the positive electrode terminal 10 toward the Z2 side is referred to as the insertion hole 7a of the packing 7, The shaft portion 11 of the positive electrode terminal 10 and the connecting portion 5a of the positive electrode current collector 5 are inserted into the insertion hole 2a of the packing 8 and the insertion hole 8a of the packing 8, By using the apparatus, it is bonded by laser welding. At this time, since both the positive electrode terminal 10 and the positive electrode collector 5 are made of Al, they are firmly bonded (welded). Thereafter, the battery case main body 3 and the lid member 2 are welded. Thereby, as shown in Fig. 2, the lithium ion battery 1 is produced.

Thereafter, as shown in Fig. 1, a plurality of lithium ion batteries 1 are arranged along the X direction. The positive electrode terminal 10 of the lithium ion battery 1 and the negative electrode terminal 20 of the adjacent lithium ion battery 1 are bonded to each other by using a flat plate bus bar 101. More specifically, as shown in Fig. 4, the lower surface of the flat-shaped bus bar 101 is attached to the upper surface 21a of the shaft portion 21 of the negative electrode terminal 20 and the upper surface 22a of the flange portion 22 In a state of being brought into contact with each other, is joined by laser welding using a laser light generating device adjusted to a predetermined intensity and irradiation time. At this time, in the shaft portion 21, welding is performed so that the welded portion W1 is formed. As a result, the negative electrode terminal 20 and the bus bar 101 are joined (welded). At this time, since the first metal layer 30 and the bus bar 101 located in the weld W1 of the negative electrode terminal 20 are all made of Al, they are firmly welded (welded). Further, since the interface I is largely separated from the bonding portion (weld portion W1) between the first metal layer 30 and the bus bar 101, heat due to bonding (welding) of the weld portion W1 is suppressed from reaching the interface I .

1, the upper surface of the positive electrode terminal 10 is bonded to the lower surface of the flat bus bar 101 by laser welding using a laser light generating device. Thereby, the positive electrode terminal 10 and the bus bar 101 are joined (welded). At this time, since the positive electrode terminal 10 and the bus bar 101 are all made of Al, they are firmly welded (welded). As a result, a battery module 100 in which a plurality of lithium ion batteries 1 are connected in series by a bus bar 101 made of a plurality of Al is manufactured.

In the manufacturing method of the first embodiment, the following effects can be obtained.

In the manufacturing method of the first embodiment, by performing the extrusion processing by the simple positioning to the overlay type clad material 120 as described above, the first metal layer (the first metal layer The negative electrode terminal 20 in which the convex portion 32 is formed in the central portion 31 of the electrode terminal 30 can be formed. Thereby, the number of steps of extrusion required for manufacturing the negative electrode terminal 20 can be reduced, the tact time can be shortened, and the yield of the negative electrode terminal 20 can be improved.

(Second Embodiment)

Next, a second embodiment of the present invention will be described with reference to Figs. 8 and 9. Fig. In this second embodiment, a case where a bottomed hole 221c is formed in the negative electrode terminal 220 is described in addition to the configuration of the first embodiment. The negative electrode terminal 220 is an example of a " battery terminal " in the present invention.

In the second embodiment of the present invention, as shown in Figs. 8 and 9, the negative electrode terminal 220 has a cylindrical shaft portion 221 and an annular flange portion 22. As a result, the negative electrode terminal 220 is formed in a rivet shape like the negative electrode terminal 20 of the first embodiment, and is formed so that the cross section along the Z direction is a T shape. The negative electrode terminal 220 is made of a clad material in which a first metal layer 30 made of Al and a second metal layer 40 made of Cu are joined together by rolling. The central portion 31 of the shaft portion 221 of the first metal layer 30 is provided with a convex portion 32 protruding toward the Z2 side in the Z direction (axial direction).

9, in the lower portion of the shaft portion 221, the second metal layer (upper surface) 21b is formed at the lower end (lower surface) of the shaft portion 221 A hole 221c is formed in which a part of the base plate 40 is cut out. That is, in the bottomed hole 221c, the bottom surface 221d inclined toward the Z1 side toward the axis A and the inner surface 221e extending from the bottom surface 221d toward the Z2 side are both composed of the second metal layer 40 . 8, the wall portion 221f provided with the inner side surface 221e of the bottomed hole 221c is provided with the shaft portion 221a so as to come into contact with the lower surface of the connecting portion 6a of the negative electrode collector 6, So that the inner surface 221e of the bottomed hole 221c is exposed to the side of Z2 so that it can be caulked to the connecting portion 6a of the negative electrode collector 6. [ Consists of.

Here, the bent portion 221f and the connecting portion 6a of the negative electrode current collector 6 may be welded by laser welding in the state where the wall portion 221f is caulked, and may not be welded. This makes it possible to connect the negative electrode terminal 220 and the connecting portion 6a of the negative electrode collector 6 more reliably when the wall portion 221f and the negative electrode collector 6 are welded. In addition, when the wall portion 221f and the negative electrode collector 6 are not welded, the welding process can be reduced, so that the manufacturing process of the battery (lithium ion battery) using the negative electrode terminal 220 can be simplified . 9, the bottom surface 221d is provided on the Z2 side with respect to the end portion 32a of the convex portion 32 so that the convex portion 32 of the first metal layer 30 is not exposed to the outside by the cutting, A hole 221c having a bottom is formed.

The other structures of the second embodiment are the same as those of the first embodiment.

In the second embodiment, the following effects can be obtained.

In the second embodiment, the negative electrode terminal 220 is made of a clad material and the first metal layer 30 of the shaft portion 221 is connected to the first metal layer 30 of the flange portion 22, (Convex portion 32) protruding toward the Z2 side in the Z direction (axial direction) relative to the surface (interface I) on the Z2 side of the metal layer 30 is formed so that the first metal layer 30 and the second metal layer 40 can be increased. Each of the shaft portion 221 and the flange portion 22 is formed of the first metal layer 30 on the Z1 side and the second metal layer 40 on the Z2 side. As a result, the bus bar 101 and the negative electrode collector 6 can be easily electrically connected through the negative electrode terminal 220.

In the second embodiment, the bottom surface 221d and the inner surface 221e are formed with a bottomed hole 221c made of the second metal layer 40 on the Z2 side end portion 21b of the shaft portion 221 The second metal layer 40 around the bottomed hole 221c (the wall portion 221f provided with the inner side surface 221e) can be deformed and caulked so that the negative electrode terminal 220 and the negative electrode collector 6 can be easily fixed. Other effects of the second embodiment are similar to those of the first embodiment.

(Third Embodiment)

Next, a third embodiment of the present invention will be described with reference to Fig. In the negative electrode terminal 320 according to the third embodiment, in addition to the first embodiment, in the case where the reaction suppressing layer 350 is disposed between the first metal layer 30 and the second metal layer 40 Explain. The negative electrode terminal 320 is an example of the " battery terminal " in the present invention.

As shown in Fig. 10, the negative electrode terminal 320 according to the third embodiment of the present invention has a cylindrical shaft portion 21 and an annular flange portion 22, and has a cross section along the Z direction And is formed so as to have a T-shape. The negative electrode terminal 320 is composed of a first metal layer 30 made of Al, a second metal layer 40 made of Cu, and a cladding material formed by bonding the reaction inhibiting layer 350 made of Ni by rolling have. A convex portion 32 projecting toward the Z2 side in the Z direction (axial direction) is formed in the center portion 31 of the shaft portion 21 of the first metal layer 30. [

The reaction inhibiting layer 350 is disposed (bonded) between the first metal layer 30 and the second metal layer 40. The reaction inhibiting layer 350 is formed such that the Al constituting the first metal layer 30 reacts with the Cu constituting the second metal layer 40 so that the weak Al- And has a function of suppressing the occurrence at the interface I with the metal layer 40. The reaction inhibiting layer 350 is formed to cover substantially the entire interface I between the first metal layer 30 and the second metal layer 40.

The reaction inhibiting layer 350 is made of Ni, which is higher in price than Al and Cu. Therefore, the thickness t3 of the reaction suppressing layer 350 is preferably as small as possible from the viewpoint of material cost, and more specifically, is preferably about 10% or less of the thickness t1 of the flange portion 22 in the Z direction. Further, since Ni is slightly less ductile than Al or Cu, it tends to break. However, even if a part of the reaction inhibiting layer 350 is broken, the effect of disposing the reaction inhibiting layer 350 is not remarkably impaired. For example, in the region other than the broken portion, it is possible to prevent the weak Al-Cu alloy from being generated at the interface I between the first metal layer 30 and the second metal layer 40, It is possible to exert an action effect of suppressing corrosion (contact of dissimilar metal contact).

As a manufacturing method of the negative electrode terminal 320 according to the third embodiment, the first metal layer 30 made of Al and the reaction suppressing layer made of Ni are formed by successively subjecting the Al plate, the Ni plate, And a second metal layer 40 composed of Cu are laminated in this order from the Z1 side in this order.

In the third embodiment, the following effects can be obtained.

In the third embodiment, the negative electrode terminal 320 is composed of a clad material and the first metal layer 30 of the shaft portion 21 is provided with the first electrode 32 of the flange portion 22, (Convex portion 32) protruding toward the Z2 side in the Z direction (axial direction) relative to the surface (interface I) on the Z2 side of the metal layer 30 is formed so that the first metal layer 30 and the second metal layer 40 can be increased. Each of the shaft portion 21 and the flange portion 22 is formed by the first metal layer 30 on the Z1 side and the second metal layer 40 on the Z2 side. Thereby, the bus bar and the negative electrode current collector can be easily electrically connected through the negative electrode terminal 320.

In the third embodiment, the metal constituting the first metal layer 30 and the metal constituting the second metal layer 40 are disposed (bonded) between the first metal layer 30 and the second metal layer 40, And a reaction inhibiting layer 350 for suppressing the reaction. As a result, the Al constituting the first metal layer 30 and the Cu constituting the second metal layer 40 react with each other to form a weak intermetallic compound (Al-Cu alloy) by the reaction suppressing layer 350 The lowering of the bonding strength due to the intermetallic compound between the first metal layer 30 and the second metal layer 40 can be reliably suppressed. In addition, corrosion inhibition of dissimilar metals can be suppressed by the reaction inhibiting layer (350). The other effects of the third embodiment are similar to those of the first embodiment.

(Fourth Embodiment)

Next, a fourth embodiment of the present invention will be described with reference to Fig. In the fourth embodiment, unlike the first embodiment, the outer portion 433 of the protruded portion 432 of the first metal layer 30, which is located outside the central portion 431, 431 are projected toward the Z2 side.

In the fourth embodiment of the present invention, as shown in Fig. 11, the negative electrode terminal 420 has a cylindrical shaft portion 421 and an annular flange portion 422. As a result, the negative electrode terminal 420 is formed in a rivet shape. The negative electrode terminal 420 is made of a clad material in which a first metal layer 30 made of Al and a second metal layer 40 made of Cu are joined together by rolling. The negative electrode terminal 420 is an example of the " battery terminal " in the present invention.

Here, in the fourth embodiment, the first metal layer 30 is formed with a portion 432 protruding toward the Z2 side in the Z direction (axial direction). The protruded portion 432 is formed continuously on the whole of the shaft portion 421 and on the shaft portion 421 side (shaft center A side) of the flange portion 422. The protruded portion 432 of the first metal layer 30 in the shaft portion 421 is located closer to the Z2 side than the Z2 side surface (interface I) of the first metal layer 30 of the flange portion 422 Respectively.

The outer portion 433 on the flange portion 422 side of the central portion 431 protrudes from the central portion 431 toward the Z2 side in the portion 432 where the shaft portion 421 protrudes. As a result, the top portion 434 on the Z2 side of the portion 432 protruding from the outer portion 433 is formed. Further, the top portion 434 has a shape that tapers toward the Z2 direction. Concretely, the top portion 434 has a shape sharpened toward the Z2 direction.

The top portion 434 of the outer portion 433 is annularly projected toward the Z2 side so as to surround the central portion 431. [ As a result, in the end surface of the negative electrode terminal 420 shown in Fig. 11, one top portion 434 is provided at the outer portion 433. Therefore, the first metal layer 30 and the second metal layer 40 are bonded to each other by the force in the XY plane direction orthogonal to the Z direction applied to either the first metal layer 30 or the second metal layer 40 It is possible that the annular top portion 434 is associated and interferes with the fact that the interface I slides (displaces) in the XY plane direction. Thereby, in the interface I, slippage in the X-Y plane direction is suppressed.

A bottomed hole 421c is formed in the lower portion of the shaft portion 421 on the side of the end portion 21b of the shaft portion 421 with a part of the second metal layer 40 being cut off leaving a peripheral edge. The bottom surface 421d of the bottomed hole 421c is located on the Z2 side of the lower surface 22e of the flange portion 422 on the Z2 side and in the vicinity of the lower surface 22e.

In the negative electrode terminal 420, the first metal layer 30 and the second metal layer 40 are all formed to be axially symmetric with respect to the axis A,

The other structures of the fourth embodiment are the same as those of the first and second embodiments.

In the fourth embodiment, the following effects can be obtained.

In the fourth embodiment, the negative electrode terminal 420 is made of the clad material and the first metal layer 30 of the shaft portion 421 is provided on the Z2 side in the Z direction (axial direction) By forming the protruded portion 432, the bonding strength between the first metal layer 30 and the second metal layer 40 can be increased. Each of the shaft portion 421 and the flange portion 422 is constituted by the first metal layer 30 on the Z1 side and the second metal layer 40 on the Z2 side. As a result, the bus bar and the negative electrode current collector can be easily electrically connected through the negative electrode terminal 420.

In the fourth embodiment, the outer portion 433 on the outer side (on the side of the flange portion 422) of the central portion 431 of the protruded portion 432 of the first metal layer 30 is formed as the center portion 431 from the Z2 side. As a result, the bonding strength between the first metal layer 30 and the second metal layer 40 at the position where the outer portion 433 is formed can be effectively increased.

The top portion 434 of the outer portion 433 is annularly projected toward the Z2 side so that the top portion 434 of the annularly protruding outer portion 433 is formed by the first metal layer 30, It is possible to effectively suppress occurrence of slippage in the XY plane direction at the interface I with the second metal layer 40. [

In the fourth embodiment, the top portion 434 of the outer portion 433 is annularly projected so as to be tapered toward the Z2 side, so that the top portion 434 is not formed into a complicated shape, and the bonding strength is improved and slippage And suppression can be easily ensured. The other effects of the fourth embodiment are similar to those of the first embodiment.

It is also to be understood that the embodiments disclosed herein are illustrative and non-restrictive in all respects. The scope of the present invention is not limited to the description of the above-described embodiments, but rather, is encompassed by the appended claims, and includes all changes (modifications) within the meaning and scope equivalent to the claims.

For example, in the first to fourth embodiments, the first metal layer 30 is made of Al and the second metal layer 40 is made of Cu, but the present invention is not limited to this. In the present invention, an Al alloy may be used instead of Al, or a Cu alloy may be used instead of Cu. Examples of the Al alloys include Al-Mn alloys of the A3000 series specified in the JIS standard. Examples of the Cu alloy include a Cu-Fe alloy such as C194.

In the first to fourth embodiments, the first metal layer 30 and the bus bar 101 to be bonded to each other are made of the same metal (Al), and the second metal layer 40 and the negative electrode The current collector 6 is made of the same metal (Cu), but the present invention is not limited thereto. In the present invention, for example, the first metal layer or the bus bar is made of Al, and the first metal layer or the bus bar is made of the Al alloy, the first metal layer and the bus bar , But may be made of the same kind of metal. Similarly, for example, in the case where one of the second metal layer or the negative electrode current collector is made of Cu and the other of the second metal layer or the negative electrode current collector is made of the Cu alloy, But the whole may be made of the same kind of metal. The " homogeneous metal " of the present invention is a broad concept that not only the metals (pure metals and alloys) composed of the same chemical components but also the other metal components include the same metal.

In the first to fourth embodiments, the negative electrode terminal made of the clad material including the first metal layer 30 made of Al and the second metal layer 40 made of Cu is used as the "battery terminal" of the present invention. The first metal layer 30 made of Al and the bus bar 101 are connected to each other and the second metal layer 40 made of Cu and the negative electrode collector 6 are connected to each other The present invention is not limited to this. In the present invention, as a "battery terminal" of the present invention, a positive electrode terminal made of a clad material including a first metal layer made of Cu and a second metal layer made of Al is used and a first metal layer made of Cu and a bus bar And the second metal layer made of Al and the positive electrode collector may be connected. In this case, in each of the embodiments of the first to fourth embodiments, Cu and Al are reversed. In this case, since a bus bar made of Cu having a small electrical resistance can be used, power consumption in the bus bar can be suppressed, and as a result, electrical loss in the battery module can be reduced.

In the first to fourth embodiments, the first metal layer 30 and the second metal layer 40 are each formed of Al and Cu, but the present invention is not limited thereto. In the present invention, for example, a combination of Al (Al alloy) and Fe (Fe alloy), Al (Al alloy) and Ni (Ni alloy ), A combination of Cu (Cu alloy) and Fe (Fe alloy), or a combination of Cu (Cu alloy) and Ni (Ni alloy).

In the first to fourth embodiments, the negative terminal 20 (220, 320, 420) includes the cylindrical shaft portion 21 (221) and the annular flange portion 22 However, the present invention is not limited to this. 12 is a modification of the first embodiment shown in Fig. 12, in which the negative terminal 520 includes a cylindrical shaft portion 21 and a radial (radial) And a flange portion 522 of a rectangular frame shape formed so as to have an extension of the flange portion 522. Also in this negative electrode terminal 520, the cross section along the Z direction is the same as the structure shown in Fig. The negative electrode terminal 520 is an example of the " battery terminal " of the present invention. Further, the shaft portion of the negative electrode terminal may be formed in a prismatic shape.

In the first to fourth embodiments, the negative terminal 20 (220, 320) is formed in a T-shape, but the present invention is not limited thereto. In the present invention, the negative electrode terminal 620 may be formed in a cross shape as in the modification of the second embodiment shown in Fig. Concretely, the shaft portion 621 of the negative electrode terminal 620 is provided with a protruding portion 621h protruding from the upper surface 21a toward the Z1 side. The projecting portion 621h is formed by projecting the first metal layer 30 of the shaft portion 621 toward the Z1 side. As a result, the negative electrode terminal 620 is formed into a cross shape by the flange portion 22 and a shaft portion 621 extending from the flange portion 22 to both the Z1 side and the Z2 side. The negative electrode terminal 620 is an example of the " battery terminal " of the present invention.

The protrusion 621h of the shaft portion 621 of the modification of the second embodiment may be applied to the configuration of the first embodiment. That is, only the projecting portion 621h may be formed without forming the bottomed hole 221c in the shaft portion 621 of the modification of the second embodiment. A hole with a bottom may be formed in the projecting portion 621h of the shaft portion 621 of the modification of the second embodiment. That is, both the bottomed hole 221c and the bottomed hole formed by the first metal layer 30 on the bottom face and the inner face on the protruding portion 621h may be formed on the shaft portion 621. [ In this case, as in the case of the bottomed hole 221c, since the wall portion of the bottomed hole constituted by the first metal layer 30 can be caulked on a bus bar (not shown), it is possible to easily fix the negative electrode terminal and the bus bar It is possible.

In the first to third embodiments, the convex portion 32 of the first metal layer 30 is formed so as to be Z2 (Z2) on the Z2 side of the flange portion 22 on the axis A of the shaft portion 21, However, the present invention is not limited to this. In the present invention, the convex portion of the first metal layer may not protrude downward from the lower surface of the flange portion on the axial center of the shaft portion.

In the first and third embodiments, the negative electrode terminal 20 (320) and the bus bar 101 are joined (welded) by laser welding and the negative electrode terminal 20 (320) The negative electrode terminal 220 and the bus bar 101 are joined (welded) by laser welding in the second embodiment. However, The invention is not limited thereto. In the present invention, the negative electrode terminal and the bus bar or the negative electrode current collector are subjected to other welding methods such as resistance welding, TIG (Tungsten Inert Gas) welding, and ultrasonic welding, depending on the positional relationship between the negative electrode terminal and the bus bar or the negative electrode collector, May be used. Further, as compared with resistance welding or the like in which welding terminals need to be disposed in the vicinity of the welding position, laser welding is preferable because welding can be performed in a position where the laser can be irradiated, and welding can be performed easily .

In the first to fourth embodiments, the convex portion 32 (protruding portion 432) is formed in the first metal layer 30 by performing the extrusion processing. However, the present invention is not limited thereto It is not limited. In the present invention, convex portions or protruded portions may be formed in the first metal layer by a processing method other than extrusion processing.

In the third embodiment, the reaction suppressing layer 350 is made of Ni. However, the present invention is not limited to this. In the present invention, the reaction inhibiting layer may be composed of an Ni alloy or other material.

In the first, second, and fourth embodiments, the negative electrode terminal 20 (220) is composed of two clad materials. In the third embodiment, ). However, the present invention is not limited to this. In the present invention, battery terminals may be constituted by four or more clad materials.

In the first to fourth embodiments, the flange portion 22 of the negative electrode terminal 20 (220, 320) is arranged outside the lithium ion battery 1 (on the upper side of the lid member 2) An example in which the portion protruding to the lower side (Z2 side) of the flange portion 22 of the shaft portion 21 (221) is disposed inside the lithium ion battery 1 (the battery case main body 3) But is not limited thereto. In the present invention, the flange portion of the negative electrode terminal may be disposed inside the lithium ion battery, and the portion projecting upward from the flange portion of the shaft portion may be disposed outside the lithium ion battery. In this case, the first metal layer on one side in the axial direction of the negative electrode terminal is made of the same metal (Cu) as the negative electrode collector, and the second metal layer on the other side in the axial direction of the negative electrode terminal is made of metal (Al).

In the first to fourth embodiments described above, the portions (protruding portion 32 and protruding portion 432) protruding toward the Z2 side of the first metal layer 30 are formed at least in the center portion of the shaft portion 21 (221) [31 (431)]. However, the present invention is not limited to this. In the present invention, the portion of the shaft portion projecting to the other side in the axial direction of the first metal layer may not be formed in the central portion of the shaft portion but may be formed only on the outer side (flange portion side) than the center portion. That is, in the fourth embodiment, the first metal layer on the outer side (on the flange side) than the central portion of the shaft portion is projected toward the other axial side than the first metal layer on the flange portion, The negative electrode terminal may be configured so that the first metal layer in the central portion of the flange portion does not protrude to the other side in the axial direction than the first metal layer in the flange portion.

In the second embodiment, the wall portion 221f provided with the inner side surface 221e of the bottomed hole 221c is deformed and caulked to connect the negative electrode terminal 220 and the negative electrode collector 6 6a are bonded to each other, but the present invention is not limited thereto. In the present invention, for example, the negative electrode terminal and the negative electrode collector may be joined (fixed) by performing welding or the like while the negative electrode collector is inserted into the hole having the bottom. Thus, it is possible to easily fix the negative electrode terminal and the negative electrode current collector.

Claims (20)

A battery terminal comprising: a shaft portion; and a flange portion having a radial extension radially from the shaft portion,
Wherein the battery terminal is composed of a clad material in which at least a first metal layer and a second metal layer are bonded,
Wherein each of the shaft portion and the flange portion is formed by the first metal layer on one side in the axial direction of the shaft portion and the second metal layer on the other side,
Wherein the first metal layer of the shaft portion has a portion protruding toward the other side in the axial direction from a surface on the other side in the axial direction of the first metal layer of the flange portion. The method according to claim 1,
Wherein the protruding portion of the first metal layer protrudes toward the other side in the axial direction from a surface on the other side in the axial direction of the first metal layer of the flange portion at least in the central portion of the shaft portion. Battery terminal. 3. The method of claim 2,
Wherein the protruding portion of the first metal layer has a convex portion protruding in a convex shape on the other side in the axial direction at a center portion of the shaft portion. The method of claim 3,
Wherein the convex portion protrudes from the other side in the axial direction of the flange portion to the other side in the axial direction on the axial center of the shaft portion. 5. The method of claim 4,
Wherein the convex portion protrudes from the other side in the axial direction of the flange portion larger than the length in the axial direction of the flange portion from the surface on the other side in the axial direction on the axial center. 6. The method according to any one of claims 1 to 5,
Wherein one of the first metal layer and the second metal layer is made of Al or an Al alloy,
And the other of the first metal layer and the second metal layer is made of Cu or a Cu alloy. 6. The method according to any one of claims 1 to 5,
Wherein a minimum length of the first metal layer of the flange portion in the axial direction is 30% or more of the length of the flange portion. 6. The method according to any one of claims 3 to 5,
Wherein a length from a surface on the other side in the axial direction of the flange portion to an end on the other side in the axial direction of the convex portion on the axial center of the shaft portion is 80% or less of the length of the shaft portion. 6. The method according to any one of claims 1 to 5,
And a bottomed hole having a bottom surface and an inner surface formed by the second metal layer is formed on the other end of the shaft portion in the axial direction. 6. The method according to any one of claims 1 to 5,
Wherein the first metal layer and the second metal layer are all formed axially symmetrically with respect to the axis of the shaft portion. 6. The method according to any one of claims 1 to 5,
Further comprising a reaction inhibiting layer for inhibiting a reaction between a metal constituting the first metal layer and a metal constituting the second metal layer. 3. The method of claim 2,
Wherein a portion of the protruded portion of the first metal layer located outside the center portion protrudes to the other side in the axial direction with respect to the center portion. 13. The method of claim 12,
And the outer portion is annularly projected to the other side in the axial direction. 14. The method of claim 13,
And the outer side portion is annularly protruded so as to be narrowed toward the other side in the axial direction. A step of forming an overlay clad material by joining at least a first metal layer and a second metal layer,
And a flange portion having a radial extension in the radial direction from the shaft portion and a flange portion extending radially from the shaft portion, wherein each of the shaft portion and the flange portion has an axial direction Wherein the first metal layer on one side of the shaft is made of the first metal layer and the other side is made of the second metal layer, And a step of forming a battery terminal so as to have a portion protruding to the other side in the axial direction with respect to the surface of the battery terminal. 16. The method of claim 15,
Wherein the step of forming the overlay type clad material comprises the step of forming a reaction suppressing layer for suppressing the reaction of the metal constituting the first metal layer and the metal constituting the second metal layer between the first metal layer and the second metal layer And a step of joining the terminal to the terminal. And a battery terminal having a flange portion and a flange portion having a radial extension radially from the shaft portion,
Wherein the battery terminal is composed of a clad material in which at least a first metal layer and a second metal layer are bonded,
Wherein each of the shaft portion and the flange portion is formed by the first metal layer on one side in the axial direction of the shaft portion and the second metal layer on the other side,
And the first metal layer of the shaft portion has a portion protruding toward the other side in the axial direction from a surface on the other side in the axial direction of the first metal layer of the flange portion. 18. The method of claim 17,
Wherein the protruding portion of the first metal layer of the battery terminal is formed at least in a central portion of the shaft portion on the other side in the axial direction with respect to the surface on the other side in the axial direction of the first metal layer of the flange portion The battery is protruding. 19. The method of claim 18,
Wherein the protruding portion of the first metal layer of the battery terminal has a convex portion protruding in a convex shape toward the other side in the axial direction at a central portion of the shaft portion. 20. The method according to any one of claims 17 to 19,
Wherein the first metal layer of the battery terminal is connected to one of a connection member or a current collector made of the same metal as the first metal layer,
And the second metal layer of the battery terminal is connected to the connection member made of the same metal as the second metal layer or the other of the current collector.

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