JPH11297300A - Lead material for battery and secondary battery with lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide, as a lead material for a secondary battery, a lead material for a battery capable of reducing weight by thinning the thickness of the whole material, having excellent corrosion resistance and weldability and electric resistance reduced remarkably compared with a conventional material. SOLUTION: By composing the lead material for a battery with a three- layered structure formed by cladding a weld layer 1 selected from Ni, a Ni-Cu alloy, a Cr-Ni alloy, a Fe-Ni alloy, a Cr-Fe alloy and a Cr-Ni-Fe alloy, and a surface layer 3, interposing a middle layer 2 comprising Cu or a heat-resistant Cu alloy, sufficient spot weld strength can be obtained, even if the thickness of the weld layer 1 to be welded to a battery is thinned. Therefore, the weld layer 1 is not necessary to have a sufficient thickness for welding, so that thickness of the whole lead material can be thinned greatly to 0.06 mm-0.5 mm to reduce weight and a cost.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to Ni-C used for electric tools, personal computers, mobile phones, electric vehicles and the like.
d, lithium ion, nickel hydride, etc. relating to a battery lead material for connecting a secondary battery;
The present invention relates to a battery lead material and a secondary battery with a lead having excellent spot weldability to an electrode, low electric resistance and high corrosion resistance by being formed in a clad material of a layer.

[0002]

2. Description of the Related Art When a pack-type secondary battery 10 of Ni-Cd, lithium ion, nickel hydride or the like is used for an electric device, for example, as shown in FIG. First lead 13 for electrically connecting.
And second leads 14 and 15 for connecting the remaining electrodes of the two batteries 11 and 12 and external terminals outside the pack type secondary battery 10 in the batteries. The electric connection between the above-mentioned batteries includes a series connection and a parallel connection.

That is, the batteries 11 and 12 are arranged in parallel so that the adjacent electrodes are opposite in polarity, and the first lead 13
Are connected to adjacent positive and negative electrodes of the battery by spot welding or the like. The pole opposite to the pole connected at the first lead is 2
The second leads 14 and 15 are welded to one ends of the second leads 14 and 15 respectively, and the second leads 14 and 15 are routed inside the battery pack 10 and the other end reaches the outside of the battery pack 10. The ends of 14 and 15 are bent to form connectors 14a and 15a, and the exposed portions connected to the external terminals are coated with gold plating or the like.

As a connection lead material for a secondary battery, it is necessary to select a material having low electric resistance, excellent corrosion resistance to an electrolytic solution used for the battery, and good weldability to an electrode and a battery case. Conventionally, such lead materials have good corrosion resistance and low electric resistance (8 to 10 μΩ ·
cm or less) Pure nickel is employed.

[0005]

With the recent increase in capacity and power of secondary batteries, nickel, which has a low electric resistance, may generate heat. Therefore, a material having a lower electric resistance is demanded. ing.

[0006] Nickel also has a problem in that nickel has a high thermal conductivity, requires a long heating time during welding, and is inferior in productivity. If it is heated too much, the battery case is heated up to adversely affect the inside of the battery.

On the other hand, copper and copper alloy have an electric resistance of 1-2 μm.
Ω · cm, which is low and has good conductivity, but has a problem in corrosion resistance and is very difficult to weld.

Recently, it has been particularly demanded that the overall thickness of the lead material be as small as possible. However, the electrical resistance that can be used as a lead material is 7 μΩ · c.
m or less, and has good corrosion resistance and weldability, and a thin material having an overall thickness of about 0.06 mm to 0.5 mm has not existed conventionally.

The present invention solves the above-mentioned problems. As a lead material for a secondary battery, a material having good corrosion resistance and weldability and having a much lower electric resistance than conventional materials, and moreover, the entire material It is an object of the present invention to provide a battery lead material capable of reducing the thickness of the battery and achieving weight reduction, and further to provide a leaded secondary battery in which such a battery lead material is effectively disposed.

[0010]

SUMMARY OF THE INVENTION The present inventors have conducted various studies on a battery lead material having a low electric resistance, a good weldability, and a high corrosion resistance. Ni alloy, Fe alloy as a welding layer with the electrode,
By forming a two-layer clad material with at least a base layer of Cu or a heat-resistant Cu alloy, satisfactory weldability and low electric resistance can be satisfied. Further, Cu or a heat-resistant Cu alloy is interposed as a base layer to obtain a required Ni alloy or Fe alloy. The above object can be achieved by forming a three-layer clad material having
Moreover, it has high strength and the total thickness is 0.06 mm to 0.5 mm
The inventor of the present invention has found that the material is thin enough.

That is, the present invention is a battery lead material having a laminated structure of a welding layer made of Ni, a Ni alloy or an Fe alloy for welding connection to an electrode, and a base layer made of at least Cu or a heat-resistant Cu alloy. . Specifically, Ni, Ni-Cu alloy, Cr-Ni alloy, Fe-N
A battery lead material having a two-layer structure in which a welding layer selected from an i-alloy, a Cr-Fe alloy, and a Cr-Ni-Fe alloy, and a base layer made of Cu or a heat-resistant Cu alloy are formed from a two-layer structure. A battery-equipped secondary battery has a battery lead material disposed between electrodes of a required battery and a welding layer is fixedly connected to the electrode by spot welding.

The present invention also provides a welding layer made of Ni, Ni alloy or Fe alloy for welding connection to an electrode,
This is a battery lead material having a laminated structure in which a base layer made of Cu or heat-resistant Cu alloy and a surface layer made of Ni, Ni alloy or Fe alloy are stacked. Specifically, Ni, Ni
-Cu alloy, Cr-Ni alloy, Fe-Ni alloy, Cr-
A lead material for a battery having a three-layer structure in which a welding layer and a surface layer selected from an Fe alloy and a Cr-Ni-Fe alloy are clad through a base layer made of Cu or a heat-resistant Cu alloy;
A battery lead material having a three-layer structure is routed between the electrodes of a plurality of batteries or a required electrode of a battery in which a welding layer is fixedly connected to the electrodes by spot welding to an external connection position, and the end of the lead is externally connected. It is a secondary battery with a lead that forms a contact.

Further, in the above-described battery lead material having a two-layer structure or a three-layer structure according to the present invention, a plating layer is provided on at least a surface layer exposed to the outside of an end for forming an external contact. Is 7 μΩ · cm or less, the thickness of the welding layer is 0.05 mm to 0.45 mm,
A battery lead material characterized in that the overall thickness is 0.06 mm to 0.5 mm is proposed as a preferable configuration.

In the lead material for a battery having a two-layer structure according to the present invention, the welding layer may be made of pure Ni, Ni (2
0-70wt%)-Cu alloy, Cr (3-20wt%)
-Ni alloy, Cr (13-30 wt%)-Fe alloy, F
e (20-80 wt%)-Ni alloy, Cr (12-25
wt%)-Ni (5-25 wt%)-Fe alloy, and the base layer is made of Cu or an additional element (Pb, F
e, Sn, Zn, P, Al, Ni, Ti, Co, Be,
A heat-resistant Cu alloy to which at least one of Mn and Zr is added).
It is proposed as a preferred configuration.

In the above-described battery lead material having a three-layer structure according to the present invention, the welding layer or the surface layer is made of pure N.
i, Ni (20-70 wt%)-Cu alloy, Cr (3-
20wt%)-Ni alloy, Cr (13-30wt%)-
Fe alloy, Fe (20-80 wt%)-Ni alloy, Cr
(12-25 wt%)-Ni (5-25 wt%)-Fe
The base layer is made of Cu or an additional element (Pb, Fe, Sn, Zn, P, Al, Ni, Ti,
A lead material for a battery characterized by being a heat-resistant Cu alloy to which at least one of Co, Be, Mn, and Zr is added) is proposed as a preferable configuration.

[0016]

FIG. 1 is a partial sectional view of a battery lead material according to the present invention. It has a three-layer laminate structure, which is a welding layer 1 with an electrode from the lower side in the figure, for example, a 30 wt% Ni-Cu alloy having a thickness of 0.12 mm, a base layer 2 having a copper thickness of 0.12 mm, and a surface layer 3 having a thickness of 0.12 mm. Is 0.
It consists of 06 mm Ni. Such a three-layer laminated structural material is formed by laminating three kinds of metals and alloy materials and pressing them with a pressing roll or the like to form a clad plate.

FIG. 2 is a sectional view showing the structure of a battery lead material having a two-layer laminate structure according to the present invention.
In the figure, a welding layer 1 with an electrode is formed from the lower side. Here, a 30 wt% Ni-Cu alloy having a thickness of 0.12 mm is formed, and a base layer 4 on the opposite side is formed of 0.12 mm thick copper. The two-layer laminated structural material was formed by laminating two kinds of metals and alloy materials and pressing them with a pressing roll or the like to form a clad plate.

The leads made of the battery lead material shown in FIGS. 1 and 2 constitute the second leads 14, 15 and the first lead 13 of the pack type secondary battery 10 shown in FIG. The first lead 13 is a lead that connects adjacent positive and negative poles of two batteries 11 and 12 that are arranged in series in parallel with the electrodes being opposite to each other. Are brought into contact and fixedly connected by spot welding.

The second leads 14 and 15 are spot-welded with the welding layer 1 to the electrode on the side opposite to the first lead 13, routed into the secondary battery 10, and having one end reaching the outside of the battery 10. The surface layer 3 is exposed to the outside of the battery 10 and is bent into the battery 10. The surface layer 3 exposed outside the battery 10 is previously plated with gold or the like in order to connect to an external terminal.

Pure copper constituting the base layer 2 having a three-layer laminate structure or the base layer 4 having a two-layer laminate structure has a very low electric resistance of about 1.75 μΩ · cm and exhibits good conductivity. By doing so, the conductivity of the entire lead material can be improved.

Pure copper shows good conductivity, but when current flows intensively into the lead, it may generate heat and cause thermal deformation. Therefore, several percent of Pb, Fe, Sn, Zn, P ,
The strength can be improved by using a heat-resistant Cu alloy to which at least one of Al, Ni, Ti, Co, Be, Mn, and Zr is added. As a preferred composition,
0.15 wt% Zr-Cu, 0.7 wt% Cr-Cu,
0.5 wt% Be-2.5Co-Cu and the like.

Although the above-mentioned copper and heat-resistant Cu alloy do not have good weldability, the weldability to the electrode can be improved by making the welding layer 1 pure Ni or a Ni alloy or Fe alloy.

As the material of the first lead 13, either a two-layer or three-layer laminate structure can be used. Here, the first lead 13 is completely inside the secondary battery 10,
Since the welding layer 1 is connected to the electrode, it is not connected to the base layer 4 at any point, so there is no need to consider contact pits with other members, and only the welding layer 1 and the base layer 4 using pure copper or heat-resistant Cu alloy are used. Is used.

The second leads 14 and 15 are routed into the secondary battery 10 and one end thereof reaches the outside of the battery 10.
Pure copper or heat-resistant Cu alloy as a base layer 2 and a surface layer 3 thereon
Is provided. As a material for forming the surface layer 3 having such a three-layer laminate structure, pure Ni or N having good corrosion resistance and weldability is used.
i alloy and Fe alloy are used.

The materials of the welding layer 1 and the surface layer 3 include pure Ni or Ni-Cu alloy having excellent corrosion resistance and weldability.
Cr-Ni alloy, Fe-Ni alloy, Cr-Fe alloy, C
Although an r-Ni-Fe alloy can be used, in particular, pure Ni having a small contact resistance is desirable because the contact resistance is taken into consideration because the external contact portion is connected to the external terminal.

According to the present invention, a battery lead material has a two-layer or three-layer laminate structure, and in the case of a three-layer structure, a pure Ni, Ni alloy, or Fe alloy having excellent corrosion resistance and weldability is used for a surface layer, and a base layer is formed. Is made of copper or a heat-resistant copper alloy, the electric resistance can be reduced to about half of the electric resistance of pure nickel, which has been conventionally used as a lead material. The weldability to the case is also good.

In the present invention, a sufficient spot welding strength can be ensured by employing pure Ni, a Ni alloy, or an Fe alloy as a material for the welding layer with the electrode. In particular, the electric resistance of Ni alloy itself is not low, but by using a clad material with copper, the electric resistance of the entire material can be reduced, and the adhesive strength between Ni alloy and copper forming the base layer , The thickness of the welding layer can be reduced, and the thickness of the entire material can be reduced.

The material for the welding layer and the surface layer is a Ni-Cu alloy,
Cr-Ni alloy, Fe-Ni alloy, Cr-Fe alloy, C
An r-Ni-Fe alloy can be adopted. The thickness ratio of the Ni alloy and the Fe alloy is preferably 10% to 80%, and if it is 10% or less, the weldability is poor. If it is 80% or more, the entire electric resistance is undesirably high. The optimal thickness ratio is 20-70
%.

It is also possible to control the electric resistance by appropriately selecting the ratio of pure Ni, Ni alloy, and Fe alloy and the thickness ratio of the welding layer, the base layer, and the remaining surface layer at the time of cladding. Pure Ni or Ni alloy in two-layer structure, F
The sheet thickness ratio between the e alloy and the copper layer is preferably 20 to 99%, and is appropriately selected according to the required electric resistance value.

The material for the welding layer and the surface layer is Ni (20 to 7).
0 wt%) -Cu alloy, for example, 30Ni-Cu alloy,
Cr (3-20wt%)-N such as 60Ni-Cu alloy
i alloy, for example, 18Cr-Ni alloy, 20Cr-Ni
Alloys such as Cr (13-30 wt%)-Fe alloys, such as 13Cr-Fe alloys, 18Cr-Fe alloys, etc.
e (20-80 wt%)-Ni alloy, for example, 36Ni
-Cr alloy (12-25 wt%)-Ni (5-25 wt%) such as -Fe alloy, 42Ni-Fe alloy, 50Ni-Fe alloy, etc.
%)-Fe alloy, for example, 18Cr-8Ni-Fe alloy, 18Cr-11Ni-Fe alloy, 15Cr-14N
An i-Fe alloy or the like is preferable.

[0031]

EXAMPLE 1 Two-layer and three-layer lead materials were prepared with the plate thicknesses shown in Table 1, and their volume resistivity and welding strength were measured. Sample No. In all of Examples 1 to 11, a low electric resistance value of 5 μΩ · cm or less and a sufficiently high welding strength were obtained.

The welding strength is 0.3 mm thick × 5 mm wide ×
One end of a lead material having a length of 50 mm was electrically spot-welded to the electrode portion of a SUS battery case at two places, and measured by a pull test at a pulling speed of 5 mm / min in a direction opposite to the welding surface.

COMPARATIVE EXAMPLE 1 For comparison, Example 1 was prepared using a lead material made of pure nickel.
The same measurement as that described above was performed to determine the volume resistivity and the welding strength. Sample No. The results of the 12 comparative examples are not good materials for both volume resistivity and welding strength.

[0034]

[Table 1]

[0035]

[Table 2]

Example 2 Further, the volume resistivity and conductivity were changed by changing the thickness ratio of the lead material consisting of two layers of pure Ni / Cu and the three-layer lead material of 30 wt% Ni-Cu / Cu / Ni. The rate was measured. The results are shown in Tables 3, 4 and 5. From this result, the plate thickness ratio of Ni was 90% in the case of two layers.
% Or less, in the case of three layers, when the plate thickness ratio of 30 wt% Ni-Cu is 20%, the plate thickness ratio of Ni is 60% or less, 30 wt% N
When the thickness ratio of i-Cu is 40%, the thickness ratio of Ni is 40%.
% Is preferable.

Example 3 The welding strength of a lead material made of pure nickel and the lead material of the present invention was measured by changing the welding voltage. As a lead material of the present invention, 30 wt% Ni-Cu / Cu /
30 wt% Ni-Cu with a thickness ratio of 1: 1: 1 (Table 6)
And 2: 1: 2 (Table 7), and 4 more
2wt% Ni-Fe / Cu / 42wt% Ni-Fe with a thickness ratio of 1: 1: 1 (Table 8) and 18wt% Cr-
Ni / Cu / 18 wt% Cr-Ni (Table 9) having a thickness ratio of 1: 1: 1 and a product made of pure nickel (Table 1)
0).

The welding conditions were the same as in Example 1. One end of the lead material was electrically spot-welded to the electrode portion of the SUS battery case at two places, and the pulling speed in the direction opposite to the welding surface was 5 m.
The welding strength was measured by a m / min pull test.

These results show that when the lead material of the present invention is used, stable tensile strength is obtained even when the welding voltage is changed, and that the tensile strength at the same voltage is small and stable. . In addition, 30wt%
2: 1: 2, in which the ratio of 30 wt% Ni-Cu is higher, has less variation in tensile strength than that in which the thickness ratio of Ni-Cu / Cu / 30 wt% Ni-Cu is 1: 1: 1. .

Further, 42 wt% of Ni-Fe or 20Cr-
A lead using Ni as a surface layer and a welding layer can obtain a higher and more stable welding strength, and is suitable for applications in which use environment such as an electrolytic solution or corrosion is not restricted and a high strength is required.

On the other hand, the measurement results of the lead material using pure nickel are shown in Table 10. When the welding voltage was high, the bonding strength was very high in some cases. Large and unreliable.

[0042]

[Table 3]

[0043]

[Table 4]

[0044]

[Table 5]

[0045]

[Table 6]

[0046]

[Table 7]

[0047]

[Table 8]

[0048]

[Table 9]

[0049]

[Table 10]

[0050]

The lead material for a battery according to the present invention uses pure Ni or a Ni alloy or Fe alloy on the side to be welded to the electrode and adopts copper for the base layer. In comparison with, the electric resistance can be reduced to about half and the corrosion resistance and weldability are excellent. Further, by selecting the thickness ratio of the clad plate, a required electric resistance value can be obtained.

In particular, when a Ni—Cu alloy is used for the welding layer of the lead material to the battery case, the Ni
Since the joining strength between the alloy layer and the Cu layer is good, even if the thickness of the Ni alloy layer to be welded to the battery is reduced, sufficient spot welding strength can be obtained. It is not necessary to provide a large thickness, the entire thickness of the lead material can be significantly reduced to 0.06 mm to 0.5 mm, and a reduction in weight and cost can be achieved.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view of a battery lead material having a three-layer structure according to the present invention.

FIG. 2 is an explanatory sectional view of a battery lead material having a two-layer structure according to the present invention.

FIG. 3 is an explanatory diagram showing a configuration example of a pack type secondary battery.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Welding layer 2, 4 Base layer 3 Surface layer 10 Secondary battery 11, 12 Battery 13 First lead 14, 15 Second lead 14a, 15a Connector

Claims (10)

[Claims] 1. A battery lead material having a laminated structure of a welding layer made of Ni, a Ni alloy or an Fe alloy for welding connection to an electrode, and a base layer made of at least Cu or a heat-resistant Cu alloy. 2. The battery lead material according to claim 1, wherein a surface layer made of Ni, a Ni alloy or an Fe alloy is laminated on a base layer opposite to the welding layer. 3. A battery lead material arranged between electrodes of a plurality of batteries and connected by welding, the material having a two-layer structure in which a welding layer with an electrode and a base layer are clad, wherein the welding layer is Ni, Ni-Cu alloy, Cr-Ni alloy, Fe-Ni
A lead material for a battery selected from an alloy, a Cr-Fe alloy, and a Cr-Ni-Fe alloy, wherein the base layer is made of Cu or a heat-resistant Cu alloy. 4. A lead material for a battery in which a lead is formed between electrodes of a plurality of batteries or from a required electrode of a battery connected by welding to an external connection position, and a leading end forms an external contact. Has a three-layer structure in which the welding layer and the surface layer are clad via a base layer, and the welding layer and the surface layer are Ni, Ni-Cu alloy, Cr-Ni alloy, Fe-Ni alloy, Cr-Fe alloy, Cr-Ni- A battery lead material selected from an Fe alloy and having a base layer made of Cu or a heat-resistant Cu alloy. 5. The battery lead material according to claim 4, wherein a plating layer is provided on at least the outer surface of the end forming the external contact. 6. The battery lead material according to claim 1, wherein the electrical resistance is 7 μΩ · cm or less. 7. The method according to claim 1, wherein the thickness of the welding layer is 0.05 mm to 0.45 mm, and the total thickness is 0.5 mm.
A lead material for a battery having a thickness of from 06 mm to 0.5 mm. 8. Ni, Ni-Cu alloy, Cr-Ni alloy, Fe-Ni alloy, Cr-Fe alloy, Cr-Ni-F
A lead material for a battery having a two-layer structure in which a welding layer selected from an e-alloy and a base layer made of Cu or a heat-resistant Cu alloy are clad is disposed between the electrodes of the adjacently disposed batteries. A rechargeable battery with leads fixedly connected by spot welding. 9. Ni, Ni-Cu alloy, Cr-Ni alloy, Fe-Ni alloy, Cr-Fe alloy, Cr-Ni-F
Cu or heat-resistant C
A battery lead material having a three-layer structure clad via a base layer made of a u-alloy is routed from a required electrode of a battery in which a welding layer is fixedly connected to an electrode by spot welding to an external connection position. A rechargeable battery with leads whose parts form external contacts. 10. The rechargeable battery with leads according to claim 9, wherein an end of the lead material forming the external contact is bent and formed, and a plating layer is provided on at least a surface layer exposed to the outside.