KR100682593B1 - Aluminum alloy plate for rectanglar cross section battery case - Google Patents

Abstract

An aluminum alloy sheet having a high product yield, good rectangular DI formability of a thin plate, and excellent weldability of a pulsed laser is obtained.

In the composition of the aluminum alloy plate, Si 0.10 to 0.60% by weight, Fe 0.20 to 0.60% by weight, Cu 0.1 to 0.70% by weight, Mn 0.30 to 1.50% by weight, Mg 0.20 to 1.20% by weight %, Zr 0.12 to 0.20% by weight (does not include upper and lower limits), Ti 0.05 to 0.25% by weight, B 0.0010 to 0.02% by weight, Cr 0.35% by weight or less, if necessary, balance Al and inevitable It consists of an impurity and makes a 45 degree interest rate 4 to 7% with respect to a rolling direction by the cylindrical container deep drawing molding method.

Description

Aluminum alloy plate for rectangular sectional battery container {Aluminum alloy plate for rectanglar cross section battery case}

INDUSTRIAL APPLICABILITY The present invention is an aluminum alloy plate used for a container (case) of a battery inserted in an electronic device such as a computer or a telephone, has a high 45 ° yield, and has good DI (deep drawing and ironing) formation. Moreover, it is related with the aluminum alloy plate for rectangular cross section battery containers excellent in pulse laser weldability.

BACKGROUND Electronic equipment and the like incorporate a battery as a driving source, and an aluminum alloy is generally used for the battery container. For example, the container of the lithium ion secondary battery for mobile telephones has a rectangular cross section, a small length, a wide width, and a large depth. It is a DI molding container with a inner product of 4 to 7 mn width × 20 to 30 mn length × 40 to 60 mn depth. The battery member is inserted in this container, and the lid is laser welded to form a closed state.

In this battery container, a relatively soft aluminum sheet of pure Al or Al-Mn type was used. However, due to the demand for not only DI moldability but also the expansion resistance against heat generation of the battery member during use, for example, Japanese Patent Application Laid-Open No. 2000-336448 (No. 11th to 14th line and 27th to 30th line) focus on this point, and elements such as Cr, Zr, Ti, etc. in addition to the alloy or Mg in which an appropriate amount of Mg is added to the Al-Mn-Si-Fe-Cu alloy By adding an appropriate amount of the alloy, an alloy having excellent press formability and expandability is proposed.

In addition, Japanese Patent Application Laid-Open No. 2001-181766 (Sections 5 to 14 and 33 to 39 on the second page) discloses a processing rate, crystal grain diameter, and intermetallic during cold rolling in an Al-Mn-Mg-Si-Fe-Cu alloy. By regulating the area occupancy of the alloy, an alloy excellent in laser weldability and breakdown strength of the case and cover is proposed.

As a blank material for DI molding a container having a rectangular cross section as described above, an elliptical shape rather than a rectangular shape is preferable in order to achieve a high yield in the panning step. Furthermore, in order to equalize the yield after DI molding, deep drawing molding is carried out in a cylindrical container. When it does, it is calculated | required that it is a board with a high 45 degree interest rate with respect to a rolling direction.

On the other hand, battery containers built in electronic devices have required thinning in terms of weight reduction. Nevertheless, Japanese Patent Application Laid-Open No. 2000-336448 does not have a description of 45 ° yield, and according to the description of Japanese Patent Laid-Open No. 2001-181766, the final rolling rate must be increased in order to increase the 45 ° yield, which impairs the DI formability of the thin plate. Pulse welding speed is slowed down.

SUMMARY OF THE INVENTION In order to solve these problems with the prior art, the present invention aims to provide an aluminum alloy plate having high product yield, good rectangular DI formability of thin plates, and excellent weldability of pulse lasers.

MEANS TO SOLVE THE PROBLEM In order to solve the subject in the said prior art, the inventors made repeated examinations, and the aluminum alloy plate which contains the appropriate amount of Zr, Ti, and B in 3000 type | system | group or the aluminum alloy which contains Mg together is a cylindrical container, even if rolling rate is low. 45 ° yield is high in deep drawing molding, excellent product yield of rectangular DI molding, good rectangular DI formability of thin plate, and no cracking and excellent productivity even if the welding speed of pulse laser is slowed down. The present invention was completed by finding the thing having.

That is, the present invention is a composition of the aluminum alloy plate,

Si: 0.10 to 0.60% by weight,

Fe: 0.20 to 0.60 wt%,

Cu: 0.10 to 0.70 wt%,

Mn: 0.60 to 1.50% by weight,

Mg: 0.20-1.20 wt%,

Zr: 0.12 to 0.20% by weight (but do not include the upper and lower limits),

Ti: 0.05-0.25% by weight,

B: 0.0010 to 0.02% by weight,

An aluminum alloy plate for rectangular cross-sectional battery containers comprising a balance Al and an unavoidable impurity and having a 45 ° rate of 4 to 7% with respect to the rolling direction by a cylindrical container deep drawing molding method. In the above and the following description, description regarding a numerical range shall include an upper limit and a lower limit unless there is a special description.

With this configuration, the yield of the product is high, the rectangular DI formability of the thin plate is good, and furthermore, the welding speed of the pull laser is effective.

Cr: 0.35% by weight or less is further contained in the composition of the aluminum alloy plate, and in addition to the above effect, the grain of the DI molded rectangular cross-sectional battery container is more beautiful.

The element which concerns on this invention is demonstrated below.

Si: 0.10 to 0.60% by weight,

Fe: 0.20 to 0.60 wt%,

Mn: 0.60 to 1.50% by weight,

These elements impart strength to the aluminum alloy plate, and finely disperse and form intermetallic compounds such as Al-Fe, Al-Mn, and Al- (Fe, Mn) -Si, thereby miniaturizing the recrystallized structure. And to impart DI moldability, the effect is less than the lower limit, the expansion resistance is insufficient, and when the upper limit is exceeded, a large particle compound is formed, and the DI moldability is lowered and the weldability is also lowered.

Cu: 0.10 to 0.70 wt%,

Mg: 0.20-1.20 wt%,

Such elements provide strength to the aluminum alloy sheet and at the same time increase the work hardening and improve the expansion resistance. However, these elements have less effect than the lower limit. If the elements exceed the upper limit, the pulse laser weldability decreases and the welding speed cannot be increased.

Zr: 0.12 to 0.20% by weight (but do not include the upper and lower limits),

Ti: 0.05 ~ 0.25 wtwt%,

B: 0.0010% to 0.02% by weight,

By coexistence of these elements, an intermetallic compound of various kinds of coagulation nuclei is generated to prevent cracking during solidification of the weld bead portion accompanied by quench solidification, thereby speeding up pulse laser welding. Moreover, when drawing-molded to a cylindrical container at low rolling rate, the high yield of 45 degree direction is provided. However, below the lower limit, the effect is less. If the upper limit is exceeded, the 45 ° yield is too high, resulting in a high yield when DI molding a rectangular cross-sectional container, and a large particle compound is formed, resulting in poor moldability.

Preferably, Zr is 0.13-0.19 weight%.

When Cr is contained in an amount of 0.35% by weight or less in addition to the above composition, the recrystallized particles are refined to finish the container beautifully. In addition, Cr is inevitably mixed from semi-finished materials and the like, and is contained in an ordinary solvent in an amount of 0.01% by weight or less. Therefore, it is necessary to contain Cr in excess of 0.01% by weight in order to make the addition effect of Cr stand out. Preferably, Cr is at least 0.1% by weight, more preferably Cr is at least 0.15% by weight.

When the upper limit is exceeded, a large particle compound is formed, and moldability is lowered.

Unavoidable impurities are other than unavoidable incorporation from raw materials such as raw materials, semi-finished products, and the like contents are, for example, 0.25 wt% or less of Zn, 0.05 wt% or less of Ga and V, and 0.05 wt% of each. It is another element of% or less, and even if it contains an element other than management in the range, it does not prevent the effect of this invention.

Next, 4 to 7% of 45 degree yield with respect to a rolling direction is demonstrated.

When the circular blank material of an aluminum rolled sheet is deep-drawn in a cylindrical container, in the case of a soft material, the iron part which developed in the shape of a mountain was formed in the periphery of a container of 0 and 90 degrees with respect to a rolling direction, and a steel processing material ( In the case of 材 加工 材, the convex part which developed in the shape of a mountain is formed in the periphery of a container of 45 degrees. Since this convex part is called an ear and needs to be removed for commercialization, it is a factor which reduces the product yield of a material. Therefore, the board | substrate with which the ear does not develop in the direction of 0, 90 degrees or 45 degrees, and does not develop normally is calculated | required and used.

Nevertheless, as described above for DI molding containers having a rectangular cross section, it is preferable to use a blank material of an elliptical shape rather than a rectangle to obtain a high yield in the punching step, while the long or short radius of the elliptical blank material obtained from the uniform ear plate is preferred. When parallel to the rolling direction of a plate, a mountain-shaped convex part develops in the periphery of a 0 and 90 degree direction by drawing, and a valley is formed in a 45 degree direction, and product yield falls.

At that time, by using a plate material in which the ear develops in the 45 ° direction in advance, the ear can be uniformly molded by DI processing, and the product yield can be improved.

That is, the battery container of the above-described conventional portable device can obtain a DI product having a high product yield by using an aluminum alloy plate having a 45 ° yield of 4% or more and 7% or less for the blank material.

Referring to the accompanying drawings, first, Fig. 1 is a perspective view of a cross-sectional rectangular battery container with pulse laser welding, where 1 is a container, 2 is a cover, and 3 is a welding line in which pulse 1 and 2 are pulse laser welded. Fig. 2 is a plan view of an elliptical blank material when drawing the container 1, where 4 is a blank material, and 5 is an imaginary line showing the position where the punches at the time of DI processing fit.

Next, the preferable manufacturing method of the aluminum alloy plate which concerns on this invention is demonstrated. The aluminum alloy molten metal having the above-described composition is ingot by semi-continuous casting method, homogenized and hot rolled, and then subjected to intermediate rolling to undergo final rolling. An aluminum alloy plate having the strength and the 45 ° yield is obtained.

The homogenization treatment of the ingot obtained as a result of casting by the semi-continuous casting method is to maintain the high temperature to ease the rolling to eliminate the unevenness of the casting composition in order to facilitate rolling, and the temperature is, for example, at 500 to 600 ° C. for 1 hour. It is preferable to maintain abnormality. If the heating temperature is too low or the holding time is too short, the size of the precipitate is small, so that the recrystallized particles are loosened during annealing and the appearance grain after DI molding is not completed cleanly. Moreover, even if the final rolling rate is low, the yield may easily exceed 7% and a predetermined strength cannot be obtained. If heating temperature is too high, there exists a possibility of partial melting. More preferably, the temperature of a homogenization process is the range of 520 degreeC or more and 590 degrees C or less.

In order to refine the recrystallized structure, the intermediate annealing is preferably a continuous annealing rate of 5 ° C./sec or more at a heating rate of 400 ° C. or higher, and at a high temperature, it can also serve as a solution solution. The holding time is preferably within 10 seconds.

Final rolling has a large impact on 45 ° yield with homogenization temperature. Therefore, by maintaining the homogenization treatment at 500 to 600 ° C. for 1 hour or more and making the final rolling rate 25 to 55%, an aluminum alloy plate having a 45 ° yield of 4 to 7% can be obtained. In the final rolling, not only the predetermined strength cannot be obtained when the rolling ratio is lower than the lower limit, but the 45 ° yield is low, and when the upper limit is exceeded, the 45 ° yield becomes too high, and when the DI cross section of the rectangular cross section container is formed, the product yield decreases. At the same time, the ductility is low, 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 of 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 a battery by inserting a battery member, then fitting the cover and pulse laser welding the matched portion, and the container is heat-treated by heating at a temperature of 40 to 170 ° C. before inserting the battery member. It is possible to increase the strength, so that it can be used in a stable state.

Next, the pulse laser welding which fixes a cover to a container is demonstrated.

The lid is fitted to the vessel and the welded portion is welded using an inert gas such as argon as the assist gas in the atmosphere or, if necessary. The welding conditions depend on the plate thickness, and the welding takes into account the pulse time, power, defocusing distance, welding speed and the like. That is, although the pulse time 0.3-5 ms, 1.5-15 Joul / spot, defocusing distance -5-+10 mm, welding speed 1-30 mm / sec can be employ | adopted suitably, such conditions are limited to the above. It is not.

Next, a specific Example is described.

(First embodiment)

The molten aluminum alloy was melted, and the ingot was cast at a thickness of 530 mm, a width of 1100 mm, a coolant of 2.5 to 3.0 l / cm · min and a withdrawal speed of 40 to 60 mm / min by a semi-continuous casting method. . The addition of Zr used Al-Zr master alloy, the addition of Ti used Al-Ti master alloy, and the addition of B used Al-Ti-B master alloy. The composition is shown in Table 1.

Next, the ingot was homogenized after face treatment, hot rolling after holding was started, and a hot rolled sheet having a thickness of 6 mm was obtained at a termination temperature of 400 ° C. Next, the cold rolled sheet of various thickness was obtained by cold rolling 4 pulses, and the intermediate annealing process was performed. The intermediate annealing treatment was heated to 520 ° C. by electromagnetic induction heating, held for a few seconds, and then quenched. After quenching, the final cold rolling was performed to obtain a rolled plate having a thickness of 0.6 mm. The following measurements were made using this rolled sheet. The results are shown in Table 2.

<45 ° interest rate>

The circular blank material was deep-drawn molded to the cylindrical container and the 45 degree yield was measured.

The 45 ° yield was calculated by the following equation.

45 ° Rate (%) = 100 (H1 + H2) / 0.5 (H1 + H2)

Where H1 is the average distance from the bottom to the floor

        H2: Average distance from bottom to valley

<Manufacture yield>

The elliptical blank material was ironed after drawing molding, to prepare a container having an inner product of 5 mm long x 25 mm wide x 50 mm deep, and cut to flatten the container periphery to measure the product yield of the material. Ironing rate was 50%.

Product yield was calculated by the following equation.

Product yield (%) = product weight / oval blank material weight x 100

<Weldability>

The obtained plate was pasted as a common material and pulsed laser welding was performed on the following conditions, and the presence or absence of the crack was confirmed with the optical microscope of 40x. Another substrate was welded with 1100 ash, but the same result was obtained when welding with a common material. 0 marks for cracking and X marks for cracking.

<Pulse laser welding>

Welding speed low speed 5mm / sec.

             High speed 20mm / sec.

1 pulse time 0.5ms

2.5Joul output / spot

Defocusing distance adjustable to 1 mm weld width

Frequency 100Hz

Table 1

Composition (Unit: weight%)

Alloy code Si Fe Cu Mn Mg Zr Ti B Cr Remarks A 0.20 0.50 0.15 0.70 0.90 0.14 0.11 0.004 - Invention B 0.20 0.55 0.15 1.00 0.80 0.15 0.11 0.005 - 〃 C 0.50 0.30 0.60 1.40 0.40 0.18 0.14 0.010 0.30 〃 D 0.20 0.55 0.64 1.00 0.80 0.15 0.11 0.0018 - 〃 E 0.20 0.55 0.64 1.00 0.80 0.15 0.11 0.0015 - 〃 F 0.20 0.55 0.64 1.00 0.80 0.15 0.11 0.0015 〃 G 0.20 0.55 0.64 1.00 0.80 0.15 0.11 0.0018 0.30 〃 H 0.15 0.55 0.15 1.00 0.8 0.15 0.13 0.0017 - 〃 I 0.15 0.55 0.15 1.00 0.8 0.15 0.13 0.0020 0.25 〃 J 0.20 0.52 0.15 1.19 0.25 0.14 0.06 0.0015 - 〃 K 0.20 0.42 0.64 1.03 0.62 0.15 0.07 0.0016 - 〃 L 0.15 0.38 0.15 1.05 1.00 0.15 0.07 0.0017 - 〃 M 0.20 0.40 0.60 1.0 0.60 - - - - Comparative example N 0.15 0.39 0.16 1.0 1.00 - - 0.010 - 〃 O 0.20 0.55 0.64 1.0 0.80 0.15 0.01 - - 〃 P 0.20 0.55 0.64 1.0 0.80 0.01 0.11 - - 〃 Q 0.30 1.2 0.3 0.5 0.5 0.2 0.15 - 0.30 〃 R 0.15 0.38 0.15 1.05 1.00 - 0.10 0.010 - 〃 S 0.20 0.60 0.15 1.0 0.80 0.15 - 0.010 - 〃 T 0.15 0.38 0.15 1.05 1.00 0.25 - - - 〃 U 0.15 0.38 0.15 1.05 1.00 - 0.30 - - 〃 V 0.15 0.38 0.15 1.05 1.00 - - 0.05 - 〃

Note 1. Residual Al and Other Inevitable Impurities

Table 2

Condition and measurement result

Sample number Use alloy code Homogenization Treatment Temperature ℃ X Time Rolling Rate After Intermediate Annealing (%) 45 ° interest rate (%) Product yield% product Weldability Cracks Low Speed, High Speed Load capacity (MPa) Remarks One A 590 X 5 30 5.5 55 volumes O O 207 Invention 2 B 〃 50 6.0 55 volumes O O 215 〃 3 C 525 X 5 40 6.5 60 wu O O 231 〃 4 D 590 X 5 50 6.5 60 volumes O O 237 〃 5 E 〃 30 5.4 54 Volume O O 239 〃 6 F 〃 30 5.6 56 sheep O O 245 〃 7 G 〃 40 6.4 59 right O O 248 〃 8 H 〃 35 6.0 57 sheep O O 220 〃 9 I 〃 35 6.1 58 wu O O 230 〃 10 J 〃 32 5.4 54 Volume O O 203 〃 11 K 〃 31 6.0 57 sheep O O 254 〃 12 L 〃 32 5.8 59 sheep O O 208 〃 13 M 〃 31 2.0 35 volume X X 250 Comparative example 14 N 〃 32 2.2 37 sheep X X 205 〃 15 O 〃 30 5.0 51 volume O X 254 〃 16 P 〃 32 3.1 44 sheep X X 251 〃 17 Q 〃 30 7.5 Cracking O X 240 〃 18 R 〃 30 3.5 45 volume X X 205 〃 19 S 〃 30 5.0 52 sheep X X 210 〃 20 T 〃 32 8.9 Cracking O X 225 〃 21 U 〃 32 3.9 Cracking O X 215 〃 22 V 〃 33 2.1 Cracking X X 201 〃

Note 2. 0 votes: no cracks X votes: cracks

From the results of Tables 1 and 2, Zr, Ti, and B coexist together as examples of the present invention, and the samples (Sample Nos. 1 to 12) having a 45 ° interest rate within the scope of the present invention have a high product yield and a welding speed of a pulse laser. Even if it is fast, it can be seen that weld cracking does not occur and the weldability is excellent. In addition, it turns out that the sample (Sample No. 3, 7, 9) which exists in the range of this invention containing Cr is excellent in the product grain of a container.

On the other hand, as a comparative example, it can be seen that Zr, Ti, and B coexist within an impurity range, and a sample having a low 45 ° yield (sample number 13) has a low product yield and a weld crack, and thus low weldability. .

In addition, it can be seen that Zr, Ti, and B alone or two-element coexistence samples (Sample Nos. 14 to 22) generate weld cracks and have low weldability.

In addition, it turns out that the sample (Sample No. 20-22) whose content of Zr, Ti, and B exceeds the range of this invention generate | occur | produces a crack at the time of DI shaping | molding, and it is inferior to moldability.

As described above, the aluminum alloy sheet of the present invention has a high 45 ° yield and excellent pulse laser weldability, so that a battery container having a rectangular cross section can be manufactured with high yield, and the lid is fastened to the container at high speed. Since it can weld, it has various industrial effects, such as productivity in manufacture of a battery.

Claims (2)

Si: 0.10 to 0.60% by weight, Fe: 0.20 to 0.60 wt%, Cu: 0.10 to 0.70 wt%, Mn: 0.60 to 1.50% by weight, Mg: 0.20-1.20 wt%, Zr: 0.12 to 0.20% by weight (but do not include the upper and lower limits), Ti: 0.05-0.25% by weight, B: 0.0010 to 0.20% by weight, Consisting of Al and unavoidable impurities An aluminum alloy sheet for rectangular cross-sectional battery containers, wherein a 45 ° yield is 4 to 7% with respect to the rolling direction by a cylindrical container deep drawing molding method. The method of claim 1, An aluminum alloy sheet for rectangular cross-sectional battery containers, which further contains 0.35 wt% or less of Cr and has a more beautiful grain texture.

Images