KR101012530B1 - Aluminum/Nickel Clad Material, and Method for Manufacture Thereof and Exterior Terminal for Electric Cell - Google Patents

Abstract

In the aluminum / nickel cladding material 1 of the present invention, the aluminum layer 3 formed of pure aluminum and the nickel layer 2 formed of pure nickel are diffusion-bonded, and the hardness of the nickel layer 2 is Hv 130 to 170. It is made. In this cladding material 1, the aluminum layer 3 and the nickel layer 2 are excellently peeled by diffusion bonding through an Al-Ni-based intermetallic compound layer having a thickness of 0.4 to 10.0 µm, preferably 1.0 to 6.0 µm. Strength can be obtained. Even if ultrasonic cladding is applied to the clad material, stable weldability to the aluminum material is obtained, and shape defects are less likely to occur even when bending is performed. For this reason, it is suitable as a raw material of a battery external terminal.

Aluminum, Nickel, Clad Material, Battery, Terminal

Description

Aluminum / Nickel Clad Material, and Method for Manufacture Thereof and Exterior Terminal for Electric Cell}

The present invention relates to an external terminal coupled to a battery outer case and an aluminum / nickel clad material that can be suitably used as a material thereof.

Small electronics and electronic devices such as mobile phones and notebook computers are equipped with small batteries. Some of these small batteries have an outer case formed of pure aluminum. The electricity generated by the battery is supplied to various electronic components through an external terminal attached to the outer case made of pure aluminum and a conductive member bonded thereto. The conductive member is usually formed of pure nickel having excellent corrosion resistance and durability.

The external terminal has a rectangular shape of about 3 mm in width and 20 mm in length. The external terminal includes, for example, an aluminum layer formed of pure aluminum in consideration of the bonding property between an outer case made of pure aluminum and a conductive member made of pure nickel, as described in Japanese Patent Application Laid-Open No. 2001-6746; Some nickel layers formed by pure nickel are formed of bonded aluminum / nickel cladding materials.

Conventionally, this aluminum / nickel cladding material overlaps a nickel sheet formed by pure nickel and an aluminum sheet formed by pure aluminum, and cold rolls the stacked sheets through a pair of rolls, and then press (Iii) Diffusion annealing is performed on the sheet to produce an aluminum layer and a nickel layer by diffusion bonding. The reduction ratio in cold press welding is about 60% or more so that the joining of the sheet | seat that the sheet | seat does not peel in a post process is obtained. In addition, diffusion annealing at high temperature is thought to produce an Al-Ni-based intermetallic compound that is vulnerable to the interface between the aluminum layer and the nickel layer, and deteriorates the peel strength between the aluminum layer and the nickel layer. It is becoming. For this reason, diffusion annealing is usually performed by holding for a short time at low annealing temperature of about 400 degreeC or less so that the said intermetallic compound does not produce | generate. A battery external terminal is usually manufactured by slitting the aluminum / nickel clad material into a strip having the same width as the required external terminal width along the longitudinal direction, and shearing the obtained strip to the required length.

The external terminal is conventionally joined to a battery outer case by spot welding (resistance welding). In the spot welding portion, aluminum and nickel of the clad material are welded and coagulated to produce an intermetallic compound. Therefore, the electrical resistance increases in the weld portion, and the efficiency of the battery decreases. For this reason, in recent years, external terminals have been joined by ultrasonic welding. In ultrasonic welding, since the aluminum layer is pressed against the battery case without melting the welded portion, the intermetallic compound is not produced and the decrease in battery efficiency can be prevented.

However, when ultrasonic welding is performed using a battery external terminal made of aluminum / nickel clad material joined by conventional cold press welding, there is a problem that the bonding strength is large and the bonding property is unstable.

In recent years, various curved shapes such as Z-shaped are required as external terminals. When the external terminal of this type is formed by the conventional clad material, there is a problem that large spring-back is likely to occur during bending processing, and shape defects are likely to occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is a battery external terminal which is stable in melt bonding even when ultrasonic welding is applied and hardly generates shape defects even after bending, an aluminum / nickel clad material which is preferable as a material thereof, And it aims to provide the manufacturing method.

MEANS TO SOLVE THE PROBLEM This inventor becomes unstable at the time of ultrasonic welding using the external terminal for batteries manufactured with the conventional aluminum / nickel cladding material, and the conventional aluminum / nickel cladding material is a reason for the easy shape defect in processing. As a result of careful investigation, it was found that the cause is that the nickel layer of the aluminum / nickel cladding material is very hard. In addition, when Al-Ni-based intermetallic compounds are formed at the interface between the aluminum layer and the nickel layer during diffusion annealing, it is thought that the peel strength between the aluminum layer and the nickel layer deteriorates, but the Al-Ni-based intermetallic compound is deteriorated. It has been found that the peel strength is rather improved in the specific thin region of. The present invention has been made based on this finding.

That is, in the aluminum / nickel cladding material of the present invention, an aluminum layer formed of pure aluminum with a purity of aluminum of 98 mass% or more and a nickel layer formed of pure nickel with a purity of 98 mass% or more of nickel are diffusely bonded to each other. The hardness is Hv 130 to 170. It is preferable that the thickness of the said aluminum layer shall be 25-100 micrometers, and it is preferable that the thickness of the said nickel layer shall be 50-200 micrometers.

According to this aluminum / nickel cladding material, since the nickel layer has a hardness of Hv 130 to 170 and the nickel layer is not excessively hard, the ultrasonic vibration is applied from the ultrasonic vibration output terminal (horn tip) to the nickel layer during ultrasonic welding. Since it is quickly transmitted to the aluminum layer through, stable weldability is obtained. In addition, since no excessive spring back occurs, good moldability is obtained. On the other hand, since the nickel layer does not soften excessively, when the clad material is sheared to obtain a workpiece such as an external terminal for a battery or a material thereof, projections (burrs) are hardly generated at the leading edge of the workpiece. If there is a burr, the workpiece is not in close contact with the welding partner material, and ultrasonic vibration is difficult to transmit. In the clad material, since burrs are less likely to form on the workpiece, ultrasonic vibration is transmitted quickly, and good ultrasonic weldability is obtained.

In the aluminum / nickel cladding material, the aluminum layer and the nickel layer are preferably diffusion welded through an Al—Ni-based intermetallic compound layer having a thickness of 0.4 to 10.0 μm, preferably 1.0 to 6.0 μm. Although the Al-Ni-based intermetallic compound itself is fragile, there is no fragility in the region near the boundary between the nickel or aluminum layer and the intermetallic compound layer, and the nickel or aluminum layer and the intermetallic compound layer are satisfactorily bonded. When the thickness of the intermetallic compound layer is about 0.4 to 10.0 µm, since the fragility of the intermetallic compound layer itself is less likely to appear, the bonding between the aluminum layer and the nickel layer is relatively good. Moreover, especially excellent bonding property is obtained by making the thickness of the said intermetallic compound layer into 1.0-6.0 micrometer. For this reason, even if the cladding material or the processed piece is subjected to strict molding, the aluminum layer and the nickel layer are hardly peeled off, and excellent molding processability is obtained.

The aluminum / nickel cladding material is preferable as a material of the battery external terminal, and the aluminum / nickel cladding material can be easily produced by performing shear processing such as cutting or punching by shearing. There is a number.

The aluminum / nickel cladding material is an aluminum sheet in which a nickel sheet formed of pure nickel with a purity of 98 mass% or more is heated to 100 to 300 ° C., and the heated nickel sheet and an aluminum sheet formed of pure aluminum with a purity of 98 mass% or more. And press-bonded at a reduction ratio of 10 to 17%, the resulting press-contacting sheet can be easily manufactured by diffusion annealing. The diffusion annealing is preferably performed in a temperature range of 500 to 600 ° C.

As described above, according to the aluminum / nickel cladding material of the present invention, since the nickel layer is adjusted to a hardness of Hv 130 to 170, stable weldability at the time of ultrasonic welding is obtained, and excessive spring back is suppressed. Excellent bending workability For this reason, it is suitable as raw materials, such as a battery external terminal. Moreover, according to the manufacturing method of this invention, an aluminum / nickel clad material provided with the nickel layer of predetermined hardness can be manufactured easily, without requiring a special installation.

1 is a schematic cross-sectional view of an aluminum / nickel clad material according to the present invention.

Fig. 2 is an explanatory diagram for measuring the bonding strength of the pressure-contacting sheet and the peeling strength of the clad sheet after diffusion annealing.

3 is an explanatory diagram of a bending test method of an aluminum / nickel clad material test piece.

4 is an explanatory diagram of 180 ° bending test tips of aluminum / nickel clad material test pieces.

In the aluminum / nickel cladding material 1 according to the embodiment of the present invention, as shown in FIG. 1, the aluminum layer 3 and the nickel layer 2 are press-bonded by diffusion bonding, and the nickel after diffusion annealing is used. The hardness of the layer 2 is Hv 130-170.

The aluminum layer 3 and the nickel layer 2 are formed of pure aluminum and pure nickel, respectively. The higher the purity of aluminum and nickel, the more preferable. However, in the present invention, impurities of up to 2 mass% are allowed, and the purity of aluminum and nickel is 98 mass% or more, preferably 99 mass% or more, and more preferably 99.9 mass%. It is preferable to use one.

The hardness of the nickel layer 2 is important in the present invention and is set to Hv 130 to 170 in Vickers hardness. The hardness of the nickel layer 2 has a great influence on ultrasonic weldability, molding processability, etc., and when Hv 170 is exceeded, the shape defect due to spring back during molding processing tends to be excessive, and the ultrasonic wave is nickel layer during ultrasonic welding. It becomes difficult to transfer from (2) to the aluminum layer 3, and welding of the aluminum layer 3 and the exterior case of a battery becomes unstable, and stable weldability is no longer obtained. On the other hand, when the Hv is less than 130, the strength decreases, and a large burr is formed at the end of the cut surface during shear processing such as slits. If burrs are formed on the outer circumferential edges of the external terminals, gaps are formed between the battery case and the ultrasonic vibration output ends of the ultrasonic welding device, making it difficult to adhere. Therefore, ultrasonic vibrations are difficult to transmit and cause welding failure. For this reason, in this invention, the hardness of the nickel layer 2 shall be Hv130-170, Preferably hardness Hv140-160.

The aluminum layer and the nickel layer are diffusion bonded by diffusion annealing. Due to this diffusion bonding, an Al-Ni intermetallic compound may be produced at the bonding interface. Since the Al-Ni intermetallic compound itself is fragile, it was thought to reduce the peel strength between the aluminum layer and the nickel layer. However, in the region where the thickness of the Al-Ni-based intermetallic compound layer formed at the interface between the aluminum layer and the nickel layer is extremely thin, it was found that the bonding strength did not decrease but rather improved in some cases. When the thickness of the said intermetallic compound layer is about 0.4-10.0 micrometers, it has a peeling strength of the grade which is satisfactory practically. In particular, by making the thickness of the intermetallic compound layer about 1.0 to 6.0 mu m, the peel strength becomes very high, as apparent from the examples described later, and it is possible to apply sufficiently to strict molding processing.

As for the thickness of the said aluminum layer 3, 25-100 micrometers is preferable. If the aluminum layer 3 is very thin, it becomes difficult to press-contact with the nickel layer 2 in the manufacturing process, while if it is very thick, ultrasonic welding of the battery case is difficult. For this reason, 25-100 micrometers is preferable, More preferably, it is about 30-70 micrometers. Although the thickness of the said nickel layer 2 is 50 micrometers or more in order to ensure ultrasonic weldability and durability, even if it is very thick, Since only cost rises, it is good to set it as 200 micrometers or less, Preferably it is 150 micrometers or less.

Next, the manufacturing method of the aluminum / nickel clad material of the said embodiment is demonstrated.

The aluminum / nickel cladding material prepares an aluminum sheet formed of pure aluminum and a nickel sheet formed of pure nickel, heats the nickel sheet to 100 to 300 ° C., overlaps the heated nickel sheet with the aluminum sheet, and pairs. Roll pressing is carried out at a reduction ratio of 10 to 17% through the gap between the rolls, and is produced by diffusion annealing the press contact sheet to which the aluminum layer and the nickel layer thus obtained are bonded. Moreover, the reduction ratio (%) is calculated as (thickness decreasing by reduction) / (original total thickness) x 100.

By heating the said nickel sheet at 100-300 degreeC, the press contact sheet which has sufficient bonding strength about 2 N / mm or more can be obtained also by the low pressure drop of 10 to 17%. If the heating temperature of a nickel sheet is less than 100 degreeC, even if it roll-contacts at 17% of the reduction ratio, the bonding force with an aluminum sheet may be insufficient, and it may peel in the process after press welding. On the other hand, when it exceeds 300 degreeC, the lubrication of the roll at the time of pressure welding will be severe, a lubrication defect will arise and it will become difficult for pressure welding. For this reason, the heating temperature of a nickel sheet is 100-300 degreeC, Preferably it is 150-250 degreeC. Moreover, after heating the nickel sheet to a predetermined temperature, it is preferable to roll-contact as quickly as possible, and it is recommended to press-contact with the aluminum sheet within 5 seconds after heating, preferably within 3 seconds.

On the other hand, an aluminum sheet does not need heating as a general rule, and can remain as room temperature. It is preferable to limit to 200 degrees C or less even if it heats. Since the low reduction ratio is adopted for the reduction ratio in roll welding, the thickness of the aluminum sheet before the reduction is inevitably thin. For example, when the thickness of the aluminum layer of a clad material is 25-100 micrometers, the thickness of an aluminum sheet shall be 28-111 micrometers. In the case of roll pressure welding using an aluminum sheet having a thickness of about 25 to 120 μm, when the aluminum sheet is heated above 200 ° C., the strength of the sheet decreases by heating, and the sheet is tensioned during roll pressing. It becomes unbearable to the tension imparted to it, causing elongation, or breaking in some cases.

It is necessary to make the reduction ratio in the said roll press welding into the range which is 10-17% and extremely narrow as mentioned above. If it is less than 5%, even when the nickel is heated to 300 ° C, the bonding strength between the aluminum sheet and the nickel sheet is about 2 N / mm or less, and sufficient bonding strength is not obtained, which may cause peeling. Moreover, even if it is 5% or more and less than 10%, a burr will become high and ultrasonic weldability will fall. On the other hand, if the reduction is more than 17%, the hardness after reduction exceeds Hv 170 even when the nickel sheet is heated to 300 ° C., resulting in problems in moldability and ultrasonic weldability. Therefore, the reduction ratio is 10 to 17%, preferably 11 to 15%.

In the pressure-contacting sheet bonded by roll pressure welding, the aluminum layer and the nickel layer are diffusion-bonded by diffusion annealing to form a clad material. Depending on the diffusion annealing conditions, the peel strength between the aluminum layer and the nickel layer in the clad material varies in various ways, but the peel strength of the clad material may be about 4.0 N / mm or more practically. In particular, when the cladding is subjected to strict processing, it is preferable to have sufficient peel strength of about 8.0 N / mm or more, more preferably about 10.0 N / mm or more. In order to obtain sufficient peel strength in a relatively short time, it is preferable to carry out diffusion annealing at a temperature of 500 to 600 占 폚. Although diffusion-annealing can also be performed at 400 to 450 ° C, in order to obtain sufficient peel strength, annealing time is required for 1 hour or more, and productivity is remarkably reduced. On the other hand, sufficient peeling strength can be obtained in a relatively short time of about 3 to 20 min at annealing at 500 ° C and about 1 to 5 min at 600 ° C. Furthermore, although the hardness of the nickel layer tends to be lowered by diffusion annealing, the degree becomes larger as the annealing temperature is higher and the annealing time is longer.

The bonding strength of the pressure-contacting sheet and the peeling strength of the same sheet (clad sheet) after diffusion annealing are measured by the following methods. As shown in FIG. 2, the aluminum layer 13 and the nickel layer 12 are partially peeled off at the ends of the test piece 11 taken from the pressure-contacting sheet, the peeled portions are bent vertically, and the ends thereof are tensile testers. It pulls out and calculates the peeling force required for peeling. The value is divided by the width of the test piece to determine the peel force per unit width as the bonding strength. In the clad sheet in which the aluminum layer and the nickel layer are diffusion-bonded by diffusion annealing, it is difficult to peel each layer from the end of the test piece. Therefore, before the diffusion annealing, the end portion of the press-contact sheet is peeled off in advance, and after diffusion annealing, the sheet is peeled off in advance. The peeled off portions were bent vertically, and the peeling force per unit width was obtained in the same manner as above, and this was taken as the peeling strength.

The aluminum / nickel cladding material produced as described above is slit into strips of the same width, for example, the width of the external terminals. The external terminal is manufactured by shearing a strip slit in terminal width to the required external terminal length or by punching a strip slit wider than the terminal width. Moreover, the shaping | molding process, such as bending process, is given to the plate-shaped workpiece | work processed in this way as needed, and it is processed to a desired shape.

Hereinafter, although an Example is given and this invention is demonstrated more concretely, this invention is not limitedly interpreted by such an Example.

(Example)

In the following manner, specimens of various clad materials were produced.

A nickel sheet of pure nickel (pure 99.9% or higher purity of nickel) having a width of 60 mm and a thickness of 50 μm and an aluminum sheet of pure aluminum having a thickness of 50 μm and having a purity of 99.9% or higher of aluminum having the same width and thickness were prepared. After the nickel sheet was heated in the tunnel furnace, the nickel sheet was overlapped with the aluminum sheet within about 2 seconds after exiting the tunnel furnace and pressed through a pair of rolling rolls. Table 1 shows the heating temperature of the nickel sheet of each sample and the rolling reduction rate of the roll pressing plate.

The test piece of width 10mm and length 100mm was extract | collected from the press contact sheet which the aluminum layer and the nickel layer were crimped | bonded by roll pressure welding, and the bonding strength of an aluminum layer and a nickel layer was measured by the measuring method demonstrated previously. Bonding strength is about 2N / mm or more in order to process the following processes without a problem.                 

Next, diffusion annealing was performed on the pressure-contacting sheet under the annealing conditions shown in the same table to obtain a clad material obtained by diffusion bonding the aluminum layer and the nickel layer. The peeling strength of this clad material and the hardness of the nickel layer were measured. Peel strength was measured using a test piece of 10 mm in width and 100 mm in length, and the hardness was measured by applying a load of 0.2 kgf (1.96 N) with a Vickers hardness tester.

In addition, a cross-sectional observation test piece was taken from the clad material and the average thickness of the Al-Ni-based intermetallic compound layer formed between the aluminum layer and the nickel layer of the clad material was measured. The cross-section observation test piece was embedded in a synthetic resin so that the cross section (plate thickness cross section) along the plate thickness direction was used as the observation surface, and the embedded test piece was polished so that the plate thickness cross section was exposed, and was 4000 times as SEM (scanning electron microscope). Sectional observation was performed. The measurement results are shown in Table 1. Furthermore, when the observed intermetallic compound layer was elementally analyzed by EPMA, it was confirmed that the intermetallic compound layer was formed of Al-Ni-based intermetallic compound.

Further, the clad material was fed to a slitter so that the nickel layer was lowered, and cut to obtain a strip having a width of 3 mm. The slitter has a plurality of cutting portions made up of a pair of upper and lower rotary knives, and the rotary knives cut the clad material by being close to cross each other while rotating. For this reason, the burr was formed in the lower end part of the nickel layer in one cut surface of the cut | disconnected strip, and the burr was formed in the upper end part of the aluminum layer in the other cut surface. The height (micrometer) of the burr formed in the edge part of the said nickel layer and the aluminum layer was measured with the surface roughness meter. If the burr height exceeds 10 mu m, the ultrasonic weldability is adversely affected. Therefore, the burr height is 10 mu m or less for the pass.

The strip of aluminum / nickel clad thus obtained was sheared to a length of 20 mm to obtain a weld test piece. The aluminum layer side surface of the welding test piece was contacted with the 0.5 mm pure aluminum plate (width 5mm x length 30mm), and the ultrasonic part was welded to the center part of the width direction. Welding conditions are as follows.

Ultrasonic Welding Machine: Ultrasonic Industry Co., Ltd., Model USW-2410Z15S

Press force: 200N

Duration: 0.3 sec

Peak Power: 250W

Energy: 63 J

After the ultrasonic welding, the bonding force of the welded portion was measured. As shown in Fig. 3, the welded test piece 21 and the pure aluminum plate 22 after welding are each bent vertically in an L-shape at the end of the welded portion W, the ends thereof are tensioned, and the joints are joined. The tensile force required to peel off was measured as the bonding force. Such measurement was performed 5 points for each sample, and the difference ΔF between the maximum value and the minimum value of the bonding force was obtained. It is important for the joint to obtain a stable weld joint, and if the ΔF exceeds 0.5 kgf (4.9 N), the joint stability of ultrasonic welding becomes a problem. Therefore, ΔF ≦ 4.9 N is regarded as the pass for the ultrasonic weldability.

In addition, a bending test piece S having a length of 50 mm was taken from the strip, and a stiffness tester (type 719, manufactured by PC A) was used to open the spring at an angle of 60 ° (bending of the bent portion) for easy observation. Bending was carried out in a V shape having a radius of 0.38 mm), the opening angle θ ° of the V shape portion of the test piece after processing was measured, and the springback amount Δθ = θ-60 was determined. When Δθ exceeds 20 °, deterioration of the processing precision is remarkable when bending the angle formed by two adjacent sides at 90 °, so that Δθ ≦ 20 ° is regarded as the passability. These measurement results are shown in Table 1 together.

Moreover, the 180 degree bending test was done using the said bending test piece S in the following way. As shown in FIG. 4, after bending by 180 degree centering on the center part of the longitudinal direction of the test piece S so that an aluminum layer may become inward, it returns to an original state, and the aluminum layer and nickel layer of the center part The incidence of local exfoliation was visually observed. Table 1 shows the observation results together, with AA showing no local peeling at all, A showing mild local peeling, and B showing clear local peeling.

It can be seen from Table 1 that the hardness of the nickel layer is excellent in the ultrasonic welding property and the bending processability of Examples (Samples No. 4 to 6, 10 to 13, 15 to 19, 21, 22) of Hv 130 to 170. . On the other hand, the hardness of the nickel layer was greater than Sample No. Hv 170. In 1, 7, 8, and 23, there is a problem in both the ultrasonic weldability and the bending workability. In addition, since the reduction ratio was low, the hardness of the nickel layer was set to Sample No. of Hv 120. In 3, the burr height on the aluminum layer side exceeds 10 micrometers, and weldability is falling. Sample No. 2 and 9 are not suitable for the reduction rate or the heating temperature of the nickel sheet. Therefore, the peeling strength of the pressure-contacting sheet is too small, and the nickel layer and the aluminum layer were peeled off during handling. In addition, sample No. Since the heating temperature of the nickel sheet was too high and the lubrication defect occurred, 14 was not able to press-contact.

On the other hand, in Examples (Samples No. 4 to 6, 10 to 13, 15, 18, 21) in which the average thickness of the Al-Ni-based intermetallic compound layer was 1.0 to 6.0 µm, the peel strength after diffusion annealing was 8 N / mm or more. Excellent diffusion bonding property is obtained. Sample No. with an average thickness of 0.4 µm. Sample No. of 17 or 9.8 μm 19 had a value slightly lower than the peel strength of about 5 N / mm, but in the 180 ° bending test, the local peeling was mild and had a moldability without any problem in practical use. In contrast, Sample No. wherein the intermetallic compound layer did not occur. 16 or excessively thick sample No. In 22, ultrasonic weldability and bending workability are good, but peeling strength is lowered, and the degree of local peeling is large. For this reason, the cladding material of these samples is not very suitable for the use by which strict molding process is performed. Sample No. Since the annealing time was long with respect to the annealing temperature of 550 degreeC, 20 produced | generated the intermetallic compound excessively, and peeling strength was not able to be measured. Sample No. 23 corresponds to the conventional cladding material, and since the reduction ratio during the welding process is high, a good peeling strength is obtained even at the diffusion annealing temperature of 350 ° C., but the hardness of the nickel layer is high, so that the ultrasonic weldability and the bending workability deteriorate. Is remarkable.

Claims (17)

As a sheet-like aluminum / nickel clad material in which an aluminum layer formed of pure aluminum with an aluminum purity of 98 mass% or more and a nickel layer formed of pure nickel with a purity of 98 mass% or more are diffusion-bonded, The nickel layer has a hardness of Hv 130 to 170, the aluminum layer and the nickel layer are diffusely bonded through the Al-Ni intermetallic compound layer, and the Al-Ni intermetallic compound layer has an average thickness of 1.0 to 6.0 μm. Aluminum / nickel clad material, characterized in that. delete delete The method of claim 1, The aluminum layer has a thickness of 25 to 100 µm, the aluminum / nickel clad material. delete delete The method of claim 4, wherein The said nickel layer is 50-200 micrometers in thickness, The aluminum / nickel clad material characterized by the above-mentioned. delete delete An external terminal for a battery formed of the aluminum / nickel cladding material according to claim 1. delete delete An external terminal for batteries formed by the aluminum / nickel cladding material according to claim 7. delete delete As a method for producing the aluminum / nickel clad material according to claim 1, A heating step of heating a nickel sheet formed of pure nickel with a purity of nickel of 98 mass% or more at 100 to 300 ° C., A press welding step of overlapping the heated nickel sheet with an aluminum sheet formed of pure aluminum having a purity of 98 mass% or more, and pressing the sheet at a reduction ratio of 10 to 17% to obtain a pressing sheet; It has a diffusion annealing process of diffusion annealing the pressure-contacting sheet, The diffusion annealing method of manufacturing an aluminum / nickel clad material, characterized in that for 3 to 5 minutes to maintain in the temperature range of 500 ~ 600 ℃. delete

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