JP2007305597A - Aluminum alloy plate for rectangular cross-section battery container and aluminum alloy plate rectangular cross-section battery container - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum alloy plate for a rectangular cross-section battery container and an aluminum-alloy- plate rectangular cross-section battery container, which can be manufactured with an excellent product yield. <P>SOLUTION: The aluminum alloy plate for a rectangular cross-section battery container is provided with a 45° lug rate of 4 to 7% to a rolling direction by a cylinder deep-draw forming method. And also, the rectangular cross-section battery container is manufactured by forming the aluminum alloy plate with a deep draw with a 45° ear rate of 4 to 7% to a rolling direction by a cylinder deep-draw forming method. Since the 45° ear rate is set from 4 to 7%, the product yield is improved. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to an aluminum alloy plate for a rectangular cross-section battery container used by being incorporated in an electronic device such as a computer or a telephone, and a rectangular cross-section battery container made of an aluminum alloy plate.

Electronic devices and the like have a built-in battery as a drive source, and an aluminum alloy is used for the battery container. For example, a container of a lithium ion secondary battery for mobile phones has a rectangular cross section, a thin thickness, a wide width, and a deep shape. If the specific dimensions are shown, it is a DI (deep drawing and ironing) molded container with a thickness of 4-7mm x width 20-30 x height 40-60mm. Are sealed by laser welding.

This battery container used pure Al-based and Al-Mn-based relatively soft aluminum plates. However, not only DI moldability but also swell resistance against the heat generated by battery members in use is required. From Patent Document 1, for example, the following Patent Document 1 discloses an alloy obtained by adding an appropriate amount of Mg to an Al-Mn-Si-Fe-Cu alloy, or adding an appropriate amount of elements such as Cr, Zr and Ti in addition to Mg. An alloy with excellent press formability and blistering resistance has been proposed.
JP 2000-336448 A (page 2, right column, lines 11-14, page 27, line 30-30)

In addition, Patent Document 2 below describes a case and a lid by regulating the processing rate, the crystal grain size, and the area occupancy ratio of the intermetallic compound during cold rolling for an Al—Mn—Mg—Si—Fe—Cu alloy. We propose an alloy with excellent laser weldability and pressure strength.
JP-A-2001-181766 (page 2, right column, lines 5 to 14; same page, same column, lines 33 to 39)

In order to DI mold the container having a rectangular cross section, it is preferable that the blank material is elliptical rather than rectangular in order to achieve a high yield at the plate cutting stage, and in order to equalize the ear rate after DI molding. In addition, a plate having a high 45 ° ear ratio in the rolling direction when deep drawn into a cylindrical container is required. In addition, battery containers built in electronic devices are required to be thin from the viewpoint of weight reduction.

However, the one proposed in Patent Document 1 has no description about the 45 ° ear ratio, and the one proposed in Patent Document 2 requires a high final rolling ratio to increase the 45 ° ear ratio. This hinders the DI moldability of thin plates.

The objective of this invention is providing the rectangular cross-section battery container manufactured with the aluminum alloy plate for rectangular cross-section battery containers with a high product yield, and this aluminum alloy plate.

In order to solve the above-described problems in the prior art, the inventors have studied and found that if the 45 ° ear rate is high when deep drawing is performed on a cylindrical container, the product yield is high and the productivity is excellent. This completes the present invention.

That is, the present invention according to claim 1 is an aluminum alloy plate for a rectangular cross-section battery container characterized in that a 45 ° ear ratio in the rolling direction is 4 to 7% by a cylindrical container deep drawing method. Further, the present invention according to claim 2 is an aluminum alloy plate rectangular cross-section battery obtained by deep drawing an aluminum alloy plate having a 45 ° ear ratio of 4 to 7% in the rolling direction by a cylindrical container deep drawing method. It is a container.

With such a configuration, there is an effect that the yield of the product can be increased.

The aluminum alloy plate of the present invention is preferably manufactured through water quenching. Moreover, it is preferable to age harden the rectangular cross-section battery container made of an aluminum alloy plate of the present invention. More preferably, after manufacturing a rectangular cross-section battery container from an aluminum alloy plate that has been subjected to water quenching, the rectangular cross-section battery container is age-hardened.

According to the present invention, a rectangular cross-section battery container can be formed with a high yield by deep drawing an aluminum alloy plate having a 45 ° ear ratio of 4 to 7% in the rolling direction by a cylindrical container deep drawing method. It has an industrial effect that a battery can be manufactured with high performance.

Since the rectangular cross-section battery container of the present invention is obtained by deep drawing an aluminum alloy plate, first, elements related to the aluminum alloy plate will be described, but the present invention is not limited thereto. Should be noted.

Si: 0.10 to 0.60 wt%,
Fe: 0.20-0.60 wt%,
Mn: 0.60-1.50wt%,
These elements give strength to the aluminum alloy sheet and recrystallize by forming finely dispersed intermetallic compounds such as Al-Fe, Al-Mn, and Al- (Fe, Mn) -Si. Of DI and DI moldability.

Cu: 0.10 to 0.70 wt%,
Mg: 0.20-1.20wt%
These elements impart strength to the aluminum alloy plate and greatly increase work hardening and improve swell resistance.

Zr: more than 0.12 and less than 0.20wt%,
Ti: 0.05-0.25wt%
B: 0.0010 to 0.02 wt%
By making these elements coexist, they produce many types of intermetallic compounds that become solidification nuclei, prevent cracking during solidification of the weld bead part accompanying rapid solidification, and enable high speed pulse laser welding, Furthermore, it contributes to imparting a high ear rate in the 45 ° direction when drawn into a cylindrical container at a low rolling rate.

When Cr is added in an amount of 0.35 wt% or less in addition to the above composition, the recrystallized grains are refined and the skin of the container is beautifully finished. In addition, Cr is inevitably mixed from recycled materials, etc., and in normal melting, it is contained in an amount of 0.01 wt% or less, so it is necessary to contain more than 0.01 wt% in order to reveal the effect of adding Cr . Preferably, Cr is 0.1 wt% or more, and more preferably, Cr is 0.15 wt% or more.

Inevitable impurities are inevitably mixed from raw metal, return materials, etc., and their contents are, for example, Zn 0.25 wt% or less, Ga and V 0.05 wt% or less, and other 0.05 each Even if it is less than wt% and contains an element outside the control within this range, the effect of the present invention is not disturbed.

Next, the 45 ° ear ratio 4 to 7% with respect to the rolling direction, which is the main feature of the present invention, will be described.
When a circular blank of aluminum rolled sheet is deep-drawn into a cylindrical container, the soft material forms a convex shape that grows in the shape of a chevron at the periphery of the container in the 0,90 ° direction with respect to the rolling direction, and the hard-worked material is 45 °. The convex part which the mountain shape developed in the container peripheral part of a direction is formed. This convex part is called an ear and is deleted when it is made into a product, which is a factor of reducing the product yield of the material. Accordingly, there is a need and use of a uniform plate of ears that normally does not develop with the ears biased toward 0, 90 ° or 45 °.

However, for DI molding of a container having a rectangular cross section, it is preferable that the blank material is elliptical rather than rectangular because of high yield in the plate cutting stage, but the long or short diameter obtained from the uniform plate of the ear When drawing an elliptical blank that is parallel to the rolling direction of the plate, the convex shape of the chevron develops at the peripheral edge of the container in the 0,90 ° direction, and valleys are formed in the 45 ° direction to lower the product yield. It becomes.
Therefore, if a plate material whose ears are developed in the direction of 45 ° in advance is used, the ears can be uniformly formed by DI processing and the product yield can be improved.

In other words, the battery container of the above-described conventional portable device can obtain a DI product with a high product yield by using an aluminum alloy plate having a 45 ° ear rate of 4% or more and 7% or less as a blank material. .

Referring to the attached drawings, first, FIG. 1 is a perspective view of a battery container with a lid having a rectangular cross section welded by pulse laser, wherein 1 is the container, 2 is the lid, 3 is the pulse between the container 1 and the lid 2. This is a laser welded weld line. FIG. 2 is a plan view of a substantially oval blank material when the container 1 is drawn, 4 is the blank material, and 5 is an imaginary line showing the position where the punch hits when DI processing is performed.

Next, the preferable manufacturing method of the rectangular cross-section battery container made from an aluminum alloy plate which concerns on this invention is demonstrated. The molten aluminum alloy having the composition described above is made into an ingot by a semi-continuous casting method, homogenized and hot-rolled, subjected to final rolling through intermediate annealing, and an aluminum alloy plate having a predetermined strength and a 45 ° ear rate.

The homogenization of the ingot obtained by casting by the semi-continuous casting method is intended to eliminate casting segregation by maintaining the temperature at a high temperature to facilitate rolling. The temperature is, for example, 500 to 600 ° C. for 1 hour. It is preferable to hold the above. If the heating temperature is too low or the holding time is short, the size of the precipitate is small, the recrystallized grains become rough during annealing, and the appearance skin after DI molding is not finished cleanly. In addition, even if the final rolling rate is low, the ear rate tends to exceed 7%, and it is difficult to obtain a predetermined strength. If the heating temperature is too high, there is a risk of partial melting. More preferably, it is 520 ° C. or higher and 590 ° C. or lower.

In order to refine the recrystallized structure, the intermediate annealing is preferably continuous annealing at a heating rate of 5 ° C./sec or more, and the heating temperature is set to 400 ° C. or more. The holding time is preferably within 10 seconds.

The final rolling, combined with the homogenization temperature, has a large effect on the 45 ° ear rate. Accordingly, the homogenization treatment is maintained at 500 to 600 ° C. for 1 hour or longer, and the final rolling is performed at a rolling rate of 25 to 55%, whereby an aluminum alloy sheet having a 45 ° ear rate of 4 to 7% can be obtained. When the rolling ratio of this final rolling is less than the lower limit, the predetermined strength cannot be obtained, and the 45 ° ear ratio is low, and when the upper limit is exceeded, the 45 ° ear ratio becomes too high, and the rectangular cross-section container is DI molded. Yield decreases and ductility decreases, and cracks are likely to occur at the mold shoulder during DI molding.

The plate thus obtained is molded into a rectangular cross-section container having various dimensions as described above. For example, the plate thickness is 0.6 mm, and drawing and ironing are added to form a container.
The container is made into a battery by aligning the lid after the battery member is assembled and pulse laser welding the mating part. The container is heated to a temperature of 40 to 170 ° C. before the battery member is assembled. By heat-treating, it can be age-hardened to have a high strength and can be used in a stable state.

Next, pulse laser welding for fixing the lid to the container will be described.
The container is fitted with a lid, and the joint is welded in the atmosphere or, if necessary, using an inert gas such as argon as an assist gas. The welding conditions are not uniform depending on the thickness of the plate, but welding is performed by appropriately determining the pulse time, output, defocusing distance, welding speed, and the like. That is, a pulse time of 0.3 to 5 ms, 1.5 to 15 joules / spot, a defocusing distance of -5 to +10 mm, and a welding speed of 1 to 30 mm / sec. Can be appropriately employed as a guideline. There is no limit.

Next, specific examples will be described.

The molten aluminum alloy was melted, and the ingot was cast by a semi-continuous casting method with a thickness of 530 mm, a width of 1100 mm, cooling water from the mold of 2.5 to 3.0 liters / cm, and an ingot drawing speed of 40 to 60 mm / min. . Zr was added using an Al—Zr master alloy, Ti using an Al—Ti master alloy, and B using an Al—Ti—B master alloy. The composition is shown in Table 1.

Next, the ingot was homogenized after chamfering, hot rolling was started after holding, and a hot rolled sheet having a finishing temperature of 400 ° C. and a thickness of 6 mm was obtained. Next, cold-rolled sheets of various thicknesses were formed by cold rolling 4 passes and subjected to an intermediate annealing treatment. In the intermediate annealing treatment, heating was performed to 520 ° C. by electromagnetic induction heating, and after several seconds holding, water quenching was performed. A final cold rolling was performed after water quenching to obtain a rolled plate having a thickness of 0.6 mm. The following measurement was performed using this rolled sheet. The results are shown in Table 2.

<45 ° ear rate>
Circular blank material, punch diameter 33.0mm, die hole diameter 34.2mm, blank material diameter 60.0mm, lubricant: Castrol Castrol No.700 (product name), application amount: about 2.5mg / cm ² , wrinkle holding pressure It was deep-drawn into a circular container under the condition of ² kg / cm ² and the 45 ° ear rate was measured.
The 45 ° ear rate was calculated from the following equation.
45 ° ear rate (%) = (H1-H2) /0.5 (H1 + H2) x 100
Where H1: Average value of distance from bottom to mountain
H2: Average distance from the bottom to the valley

<Product yield>
Oval blank material is drawn and then ironed, and a bottomed container with a thickness of 5mm x width 25mm x depth 50mm is manufactured by the internal method, then cut to flatten the edge of the container, and the product yield of the material Was measured. The ironing rate was 50%.
Calculated from the product yield equation.
Product yield (%) = Product weight / Oval blank weight x 100

From the results shown in Tables 1 and 2, it can be seen that samples (sample numbers 1 to 12) having a 45 ° ear rate in the range of 4 to 7% as examples of the present invention have a high product yield.

On the other hand, as a comparative example, a sample (sample numbers 13 to 20) having a 45 ° ear rate of 4 to 7% and not within the scope of the present invention is found to have a low product yield.

It is a perspective view which shows the outline of the battery container with a lid of the cross-section rectangle which was pulse-laser-welded. It is a top view which shows the outline of an elliptical blank material when drawing a battery container with a rectangular cross section.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Battery container of rectangular cross section 2 Cover of container 1 Welding line 4 pulsed laser welding 4 Blank material

Claims (2)

An aluminum alloy plate for a rectangular cross-section battery container, wherein a 45 ° ear ratio in the rolling direction is 4 to 7% by a cylindrical container deep drawing method. A rectangular cross-section battery container made of an aluminum alloy plate obtained by deep drawing an aluminum alloy plate having a 45 ° ear ratio of 4 to 7% in the rolling direction by a cylindrical container deep drawing method.

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