CN105039786A

CN105039786A - Aluminum alloy sheet for battery case having good moldability and weldability

Info

Publication number: CN105039786A
Application number: CN201510266640.1A
Authority: CN
Inventors: 铃木健太; 堀久司; 金森圭治
Original assignee: Nippon Light Metal Co Ltd
Current assignee: Nippon Light Metal Co Ltd
Priority date: 2011-02-02
Filing date: 2011-12-26
Publication date: 2015-11-11
Anticipated expiration: 2031-12-26
Also published as: TWI516609B; JP2012177186A; TW201235479A; TWI595097B; CN105112730A; CN105112731B; CN105063428B; WO2012105144A1; CN105112730B; CN105039786B; CN103328667A; CN105063428A; CN105112731A; JP5725344B2; TW201514321A; CN103328667B; TWI509082B; TW201538742A; KR20130122651A; KR20150111373A

Abstract

Provided is an Al-Fe based aluminum alloy sheet having sufficiently high strength for application as a large lithium-ion battery container, as well as good moldability and good laser weldability. The aluminum alloy sheet is a cold-rolled material having an elongation of 5% or more and tensile strength of 90 MPa or more, and having: a chemical composition comprising 0.3 to 1.5 mass% Fe, 0.3 to 1.0 mass% Mn, and 0.002 to 0.20 mass% Ti, with an Mn/Fe mass ratio of 0.2 to 1.0, and the remainder comprising Al and inevitable impurities, such inevitable impurities comprising Si, Cu, and Mg in the respective amounts of less than 0.30 mass% Si, less than 0.20 mass% Cu, and less than 0.20 mass% Mg; and a metallographic structure in which the number of second-phase particles with an equivalent circle diameter of 5 [mu]m or more is less than 500/mm2. Alternatively, the aluminum alloy sheet is simply a cold-rolled annealed material having an elongation of 20% or more.

Description

The aluminium alloy plate for battery case of plasticity and welding property excellent

The application is international application no is PCT/JP2011/080130, international filing date be after the PCT international application on December 26th, 2011 enters China's stage national applications number be 201180055947.7 title be the divisional application of the Chinese patent application of " aluminium alloy plate for battery case of plasticity and welding property excellent ".

Technical field

The aluminium alloy plate of the plasticity that the secondary cell container that the present invention relates to lithium ion battery etc. uses and laser welding excellence.

Background technology

3000 of Al-Mn system is alloy because intensity, plasticity and laser welding are more excellent, is therefore used as the starting material during secondary cell container manufacturing lithium ion battery etc. gradually.Sealed by laser welding after being configured as desired shape, use as secondary cell container.Be alloy and existing 3000 to be based on alloy with above-mentioned 3000, also complete the exploitation of the secondary cell container aluminium alloy plate that intensity and plasticity have been improved.

Such as, the square-section cell container aluminium alloy plate with following characteristics is described: as the composition of aluminium alloy plate in Japanese Patent No. 4001007 publication, Si containing 0.10 ~ 0.60 quality %, the Fe of 0.20 ~ 0.60 quality %, the Cu of 0.10 ~ 0.70 quality %, the Mn of 0.60 ~ 1.50 quality %, the Mg of 0.20 ~ 1.20 quality %, the Zr of 0.20 quality % is less than more than 0.12 quality %, the Ti of 0.05 ~ 0.25 quality %, the B of 0.0010 ~ 0.02 quality %, rest part is made up of Al and inevitable impurity, with cylindrical vessel deep drawing moulding method relative to 45 ° of earing rates (Japanese: 45 ° of ear rates) of rolling direction for 4 ~ 7%.

On the other hand, recently, also developed following square lithium ion battery case aluminium alloy plate as battery container: have enough intensity and drawing-thinning drawing processibility, creep properties, laser welding is excellent, and thickness of shell when can suppress charge and discharge cycles increases.The square battery container aluminium alloy plate with following composition is described: containing more than 0.8 quality % and at the Mn of below 1.8 quality % in Japanese Patent Laid-Open 2010-126804 publication, more than 0.6 quality % and at the Mg of below 1.2 quality %, more than 0.5 quality % and at the Cu of below 1.5 quality %, Fe as impurity is limited in below 0.5 quality %, Si is limited in below 0.3 quality %, rest part is made up of Al and inevitable impurity, { the orientation density C of 001}<100> orientation is with { ratio (C/S) of the orientation density S of 123}<634> orientation is more than 0.65 less than 1.5, also have, tensile strength after finally cold rolling is at more than 250MPa below 330MPa, elongation is more than 1%.

But, when by 3000 be based on alloy and to its form improve aluminium alloy plate, known welding penetration is not enough sometimes, according to circumstances can produce abnormal bead (Japanese: ビー De), laser welding has problems.

So, also developed with 1000 the secondary cell container aluminium alloy plate of the laser welding excellence being basis.Describe in Japanese Patent Laid-Open 2009-127075 publication by carrying out pulsed laser welding to A1000 system aluminium, the generation of abnormal portion is prevented, and can be formed uniformly pulsed laser welding aluminium alloy material and the battery container of good weld part.Thus, the Ti in the past added for suppressing the coarsening of crystal grain in castingprocesses produces detrimentally affect to weld part, in order to be fetched the formation of the abnormal portion prevented when welding A1000 system aluminium by pulse laser welding, be less than 0.01 quality % as long as be defined as by Ti contained in fine aluminium.

Also have, as being the aluminium alloy improving high strength, plasticity, weldability based on alloy by 3000, propose in Japanese Patent Laid-Open 2003-7260 publication comprise 0.3 ~ 1.5 quality % Mn, more than 1.0 and at the Fe of below 1.8 quality %, the secondary cell housing aluminium alloy plate that rest part is made up of Al and inevitable impurity.Can also Cu containing 0.1 ~ 0.8 quality % and/or more than 0.10 and at the Zr of the Mg of below 1.0 quality % and/or the Cr of 0.05 ~ 0.2 quality % and/or 0.05 ~ 0.2 quality %.But, detailed investigation is not carried out to weldability.

Summary of the invention

Under most cases, although 1000 is that weldability is stablized (abnormal bead number is few), had excellent formability, there is the problem that intensity is lower.Therefore, in the evolution of the maximization of lithium ion battery, expect also to require high-strength characteristic, directly using existing problems in 1000 aluminiums being.

As mentioned above, 3000 be alloy sheets when, although intensity and dark fusion penetration can be obtained, compared with the alloy sheets being with 1000, have the tendency that poor, the abnormal bead number of plasticity is many.In addition, 1000 be alloy sheets when, although have excellent formability, abnormal bead number reduce, have the anxiety of undercapacity.

The present invention is the invention proposed to solve the problem, and its objective is that providing a kind of has the high strength that can be used in large-scale lithium ion battery container, and have excellent formability, Al-Fe line aluminium alloy plate that laser welding is also excellent.

In order to achieve the above object, the feature of the aluminium alloy plate for battery case of plasticity of the present invention and welding property excellent is, there is following chemical constitution: the Mn of the Fe containing 0.3 ~ 1.5 quality %, 0.3 ~ 1.0 quality %, the Ti of 0.002 ~ 0.20 quality %, the mass ratio of Mn/Fe is 0.2 ~ 1.0, rest part is made up of Al and inevitable impurity, and as Si, Cu and Mg of inevitable impurity, Si is less than 0.30 quality %, Cu is less than 0.20 quality %, and Mg is less than 0.20 quality %; And having equivalent circle diameter is that the second phase particles number of more than 5 μm is less than 500/mm ²metallographic.

When cold rolling material, there is the elongation values of more than 5% and the tensile strength cold rolling material of more than 90MPa.In addition, when making cold rolled annealed material, there is the elongation values of more than 20%.

Break in order to ingot bar when casting can be prevented or laser welding time bead break, can also containing the Zr of 0.05 ~ 0.20 quality %.

It is also excellent that aluminium alloy plate of the present invention has high strength, plasticity, and have excellent laser welding, therefore, it is possible to manufacture with low cost the secondary cell container that the excellent and expansion energy of airtight performance is inhibited.

Particularly when cold rolling material, have the tensile strength of more than 90MPa, when making cold rolled annealed material, elongation values is more than 20% plasticity showing excellence.

Accompanying drawing explanation

Fig. 1 is the schematic diagram of the mensuration/evaluation method of specification exception bead number, and (A) is the vertical view of welding bead (Japanese: weld ビー De), and (B) is the figure of the bead change width represented along bead length direction.

Fig. 2 is the schematic diagram of mensuration/evaluation method that fusion penetration is described, (A) is the vertical view of welding bead, and (B) is sectional view.

Embodiment

Secondary cell, by after electrode body is put into container, utilizes mounting cover such as welding grade, carries out sealing to manufacture.If this secondary cell is used for mobile phone etc., then when charging, the temperature having internal tank rises, the situation of the pressure increase of internal tank.Therefore, if the intensity forming the material of container is low, then manufactured container has the problem that large expansion occurs.Therefore, as used material, require that there is high strength.

In addition, as the method forming container, usually extrusion process is used, so require that the material self used has excellent extrusion molding.

And the method that mounting cover carries out sealing adopts welding process, therefore also requires that weldability is also excellent.And, as welding process during manufacture secondary cell container etc., adopt the situation of method of laser welding more.

On the other hand, about laser welding, the fusion penetration of the stability of (1) weld width, the stability of fusion penetration and (2) acquisition Yan Gengshen relative to weld width can be exemplified as problem.

Typically, if weld width broadens, then fusion penetration also has the tendency of intensification.Therefore, in the abnormal bead portion of local, weld width broadens, fusion penetration deepens, and when serious, penetrating of fusing department can occur, thus cause the decline of the Performance And Reliability of battery.

In addition, on the other hand, in order to investigate fusion penetration, also needing to observe a large amount of cross sections, hard work be paid., as mentioned above, due to relevant between the weld width in same alloy and fusion penetration, so detect abnormal (thick) bead by measuring weld width, the ratio of the bead of the fusion penetration exception of generation problem can be investigated simply.

The present inventor is in order to obtain high strength, extrusion molding excellence, and the abnormal bead number occurred at weld part by inquiry and the aluminium alloy plate that the laser welding known is also excellent at the fusion penetration of weld part, repeatedly conscientiously study, thus complete the present invention.

Below, its content is described.

First, the effect of each element contained in secondary cell container aluminium alloy plate of the present invention, suitable content etc. are described.

fe:0.3 ~ 1.5 quality %

Fe can increase the intensity of aluminium alloy plate, guarantees the fusion penetration in laser welding, so be essential element.If Fe content is less than 0.3 quality %, then the strength degradation of aluminium alloy plate, fusion penetration during laser welding reduces, so not preferred.If the content of Fe is more than 1.5 quality %, then Al-(FeMn)-Si system, Al when ingot bar is cast ₆the intermetallic compound crystallization that Fe etc. are thick, the plasticity of most soleplate declines, and these intermetallic compounds are easier than Al matrix when laser welding evaporates, and abnormal bead number increases, weldability declines, so not preferred.

Therefore, Fe content adopts the scope of 0.3 ~ 1.5 quality %.Preferred Fe content is the scope of 0.5 ~ 1.5 quality %.Preferred Fe content is the scope of 0.7 ~ 1.5 quality % further.

mn:0.3 ~ 1.0 quality %

Mn can increase the intensity of aluminium alloy plate, guarantees the fusion penetration in laser welding, so be essential element.If Mn content is less than 0.3 quality %, then the strength degradation of aluminium alloy plate, and fusion penetration during laser welding reduces, so not preferred.If the content of Mn is more than 1.0 quality %, then Al-(FeMn)-Si system, Al when ingot bar is cast ₆the intermetallic compound crystallization that Mn etc. are thick, the plasticity of most soleplate declines, and these intermetallic compounds are easier than Al matrix when laser welding evaporates, and abnormal bead number increases, weldability declines, so not preferred.

Therefore, Mn content adopts the scope of 0.3 ~ 1.0 quality %.Preferred Mn content is the scope of 0.3 ~ 0.8 quality %.Preferred Mn content is the scope of 0.4 ~ 0.7 quality % further.

ti:0.002 ~ 0.20 quality %

Ti works as the fine agent of crystal grain when ingot bar is cast, and can prevent casting from breaking.

Certainly, Ti can add separately, owing to can expect the micronized effect of more powerful crystal grain by coexisting with B, therefore also can add with the form of the excellent master alloys such as Al-5%Ti-1%B (Japanese: ロッドハードナー).

If Ti content is less than 0.002 quality %, then micronized effect during ingot bar casting is insufficient, so likely cause casting to break, thus not preferred.If Ti content is more than 0.20 quality %, then the TiAl when ingot bar is cast ₃etc. thick intermetallic compound crystallization, the plasticity of most soleplate is declined, so not preferred.

Therefore, Ti content adopts the scope of 0.002 ~ 0.20 quality %.Preferred Ti content is the scope of 0.002 ~ 0.15 quality %.Preferred Ti content is the scope of 0.005 ~ 0.10 quality % further.

zr:0.05 ~ 0.20 quality %

Zr and Ti is same, works, can prevent casting from breaking when ingot bar is cast as the fine agent of crystal grain.In addition, if make Ti and Zr coexist, then can preventing the welding bead portion with quench solidification from breaking when solidifying, realizing the high speed of pulsed laser welding.If make Ti, Zr and B coexist, then the effect preventing the welding bead portion with quench solidification from breaking when solidifying becomes more remarkable.Therefore, can contain as required.

If Zr content is more than 0.20 quality %, then the ZrAl when ingot bar is cast ₃etc. thick intermetallic compound crystallization, the plasticity of most soleplate is declined, so not preferred.If Zr content is less than 0.05 quality %, then cannot obtain enough effects.Therefore, preferred Zr content is 0.05 ~ 0.20 quality %.Preferred Zr content is the scope of 0.07 ~ 0.20 quality %.Preferred Zr content is the scope of 0.07 ~ 0.18 quality % further.

b:0.0005 ~ 0.10 quality %

B is also same with Ti, Zr, works as the fine agent of crystal grain when ingot bar is cast, and can prevent casting from breaking, so also can contain B as required.

If B content is more than 0.10 quality %, then TiB2 becomes the intermetallic compound of stabilization, and crystal grain micronized effect is decayed, and the appearance surfaces likely occurred after DI shaping is coarse, so not preferred.If B content is less than 0.0005 quality %, then cannot obtain sufficient crystal grain micronized effect.Therefore, preferred B content is 0.0005 ~ 0.10 quality %.Preferred B content is the scope of 0.001 ~ 0.05 quality %.Preferred B content is the scope of 0.001 ~ 0.01 quality % further.

si content as inevitable impurity: be less than 0.30 quality %

As the content of the Si of inevitable impurity, be preferably limited to and be less than 0.30 quality %.If Si content is at more than 0.30 quality %, then the intermetallic compound crystallization that Al-(FeMn)-Si etc. is thick when ingot bar is cast, plasticity declines.Preferred Si content is less than 0.25 quality %.Preferred Si content is less than 0.20 quality % further.

In the present invention, if Si content is less than 0.20 quality %, then the characteristic of plasticity and weldability etc. would not decline.

cu as inevitable impurity: be less than 0.2 quality %

As the Cu of inevitable impurity, can contain with the amount being less than 0.2 quality %.In the present invention, if Cu content is less than 0.2 quality %, then the characteristic of plasticity and weldability etc. would not decline.

mg as inevitable impurity: be less than 0.2 quality %

As the Mg of inevitable impurity, can contain with the amount being less than 0.2 quality %.In the present invention, if Mg content is less than 0.2 quality %, then the characteristic of plasticity and weldability etc. would not decline.

other inevitable impurity

Inevitable impurity is the impurity be inevitably mixed into deriving from raw material bullion, return waste material etc., their admissible content is, such as Zn is for being less than 0.25 quality %, Ni is for being less than 0.20 quality %, Ga and V is for being less than 0.05 quality %, Pb, Bi, Sn, Na, Ca, Sr are less than 0.02 quality % respectively, and other impurity are respectively less than 0.05 quality %, even if also can not harm effect of the present invention containing the element outside management within the scope of this.

the mass ratio of Mn/Fe: 0.2 ~ 1.0

In the scope of Fe, Mn content within the scope of the invention, if Mn/Fe ratio is less than 0.2, then fusion penetration during laser welding reduces, so not preferred.In the scope of Fe, Mn content within the scope of the invention, if Mn/Fe ratio is more than 1.0, then abnormal bead number increases, so not preferred.

On the other hand, when the mass ratio of Mn/Fe is cast ingot bar, the kind of the intermetallic compound of crystallization and amount have an impact.Such as, it is well known that, if Mn/Fe mass ratio increases, then Al ₆the quantity of the intermetallic compound of Mn system also increases.

On the other hand, these Al ₆the intermetallic compound of Mn etc. and Al-Fe-Si, Al ₆fe, Al ₃the intermetallic compound ratio of Fe etc., easily evaporates when laser welding and unstable.Therefore, if Mn/Fe ratio is more than 1.0, then can think laser welding time abnormal bead number increase, weldability declines.

In addition, Mn can, by being solid-solution in the thermal resistance increasing material in Al matrix, in the fusion penetration therefore when guaranteeing laser welding, be element more prior than Fe.

Therefore, if Mn/Fe ratio is less than 0.2, then can think laser welding time insufficient (incomplete) penetration.

tensile strength and elongation values

cold rolling material: the value of elongation be more than 5% and tensile strength at more than 90MPa

cold rolled annealed material: the value of elongation is more than 20%

On the other hand, when Al-Fe line aluminium alloy plate being applied to large-scale lithium ion battery container etc., not only needing that there is high strength and excellent laser welding, also needing plasticity also excellent.The intensity of material can be learnt by tensile strength when carrying out tension test, and plasticity can be known by the worth of elongation during tension test.

Detailed content is recorded in embodiment described later, as middle Al-Fe line aluminium alloy plates of the present invention adopted such as large-scale lithium ion battery containers, during for cold rolling material, the value preferably with elongation be more than 5% and tensile strength at the cold rolling material of the characteristic of more than 90MPa; During for cold rolled annealed material, the value preferably with elongation is the cold rolled annealed material of the characteristic of more than 20%.

equivalent circle diameter in metallographic is that the second phase particles number of more than 5 μm is less than 500/mm ²

Characteristic as above shows by carrying out meticulous adjustment to the metallographic of the Al-Fe line aluminium alloy plate with above-mentioned specific chemical constitution.

Specifically, as long as make the equivalent circle diameter in metallographic be that the second phase particles number of more than 5 μm is less than 500/mm ².

No matter be cold rolling material or cold rolled annealed material, metallographic does not have difference.If have metallographic as above, then cold rolling material presents the value of the elongation of more than 5% and the tensile strength of more than 90MPa, and cold rolled annealed material presents the value of the elongation of more than 20%.

Then, the method manufacturing secondary cell container aluminium alloy plate as above is simply introduced.

fusing and melting

Raw material is put in smelting furnace, if reach the temperature of fusion of regulation, then suitably drops into flux stirring, use as required spray gun etc. carry out degassed in stove after, keep tranquil, the surface of dregs from liquation be separated.

In this fusing and melting, owing to adopting the alloying constituent of regulation, so the raw material of mother alloy etc. drops into also very important again, but very importantly from molten aluminium alloy, float up to liquation face to above-mentioned flux with dregs and being separated, need the enough tranquil time.It is desirable that the tranquil time needs more than 30 minutes usually.

The molten aluminium alloy obtained by smelting furnace melting is according to circumstances different, and be sometimes transferred to by a part of liquation after keeping stove and cast, direct being ejected from smelting furnace by liquation is cast sometimes.More preferably the tranquil time is more than 45 minutes.

Also degassed (Japanese: イ Application ライ Application takes off ガス), filtration online can be carried out as required.

Mainstream type degassed online to aluminum melt, is blown into rare gas element etc. from rotor, the hydrogen in liquation diffused to carry out in the bubble of rare gas element the type removed.

During as rare gas element use nitrogen, importantly dew point is controlled at such as less than-60 DEG C.Amounts of hydrogen in ingot bar is preferably reduced to below 0.20cc/100g.

When the amounts of hydrogen of ingot bar is many, produce hole in the portion of finally solidifying of ingot bar, so need the draft of every 1 passage (Japanese: パス) in hot-rolled process to be limited to such as more than 7%, thus destroy hole.

In addition, the condition of the process that homogenizes before the hydrogen of supersaturation ground solid solution depends on hot-rolled process in ingot bar, but separate out during laser welding sometimes after the shaping of most soleplate, make in bead, to produce a large amount of pores.So the amounts of hydrogen in preferred ingot bar is below 0.15cc/100g.

casting

Ingot bar is manufactured by semicontinuous casting (DC casting).When common semicontinuous casting, the thickness of ingot bar is generally about 400 ~ 600mm, so the solidification cooling of ingot bar central part is 1 DEG C/about sec.Therefore, particularly when the molten aluminium alloy that the content of semicontinuous casting Fe, Mn is high, at ingot bar central part place, the thicker intermetallic compounds such as Al-(FeMn)-Si tend to crystallization from molten aluminium alloy.

Casting speed in semicontinuous casting depends on width, the thickness of ingot bar, but considers productivity, normally 50 ~ 70mm/ minute.But, carry out online degassed time, if consider the actual liquation residence time in degassed treatment trough, then also depend on the degassing conditions such as the flow of rare gas element, degassing efficiency in flow (the liquation supply in time per unit) the less then groove of aluminum melt is higher, more can reduce the amounts of hydrogen of ingot bar.Although also depend on the casting radical etc. of casting, in order to reduce the amounts of hydrogen of ingot bar, it is desirable to casting speed to be defined as 30 ~ 50mm/ minute.More preferably casting speed is 30 ~ 40mm/ minute.Certainly, if casting speed is less than 30mm/ minute, then productivity declines, so undesirable.In addition, obvious casting speed is slower, and the obliquity in the liquid cave (Japanese: サ Application プ) (interface of solid phase/liquid phase) in ingot bar is more slow, more can prevent casting from breaking.

homogenize process: 420 ~ 600 DEG C × more than 1 hour

The ingot bar obtained utilizing semicontinuous casting method to cast implements to homogenize process.

The process that homogenizes refers to easily be rolled and ingot bar is held in high temperature, carries out the process of residual stress eliminating casting aliquation, ingot bar inside.In the present invention, need to keep more than 1 hour at maintenance temperature 420 ~ 600 DEG C.In this situation, when also can be for making to be formed in casting, the transition element etc. of the intermetallic compound of crystallization be solid-solution in the process of matrix to a certain extent.This maintenance temperature is too low or when keeping temperature short, the solid solution of above-mentioned transition element etc. likely can not occur, and recrystallization grains is thicker, and the appearance surfaces after DI is shaped cannot precision work nattily.In addition, if keep temperature too high, then as the CuMgAl in the portion of finally solidifying of the microcosmic of ingot bar ₂deng eutectic part likely dissolve, be namely oxidized (Japanese: バーニ Application グ).The preferred treatment temp that homogenizes is 420 ~ 590 DEG C.

hot-rolled process

The ingot bar direct lifting machine after the process that homogenizes being held in high temperature with the specified time is sling, deliver to hot rolls, though relevant with the machine of hot rolls, usually by rolling pass repeatedly, the hot-rolled sheet of the thickness of regulation, such as about 4 ~ 8mm can be made and be wound on roller.

cold rolling process

Make the roller being wound with hot-rolled sheet by cold-rolling mill, usually implement the cold rolling of several passage.Now, there is work hardening due to the viscous deformation because of cold rolling importing, so process annealing process can be carried out as required.Usual process annealing is also sofening treatment, so different because of material, can insert in batch furnace by cold roll, keep more than 1 hour with the temperature of 300 ~ 450 DEG C.If keep temperature lower than 300 DEG C, then soften and cannot be promoted, if keep temperature more than 450 DEG C, then can cause the increase of processing cost.In addition, as process annealing, if utilize continuous annealing furnace to keep within 15 seconds at the temperature of such as 450 DEG C ~ 550 DEG C, then cool rapidly, then also can double as solution treatment.If keep temperature lower than 450 DEG C, then soften and cannot be promoted, if keep temperature more than 550 DEG C, be then likely oxidized.

final annealing

In the present invention, the final annealing carried out after finally cold rolling can be at temperature 400 ~ 500 DEG C, such as keep the batch-type process of more than 1 hour with annealing furnace, if utilize continuous annealing furnace to keep within 15 seconds at the temperature of such as 500 DEG C ~ 550 DEG C, then cool rapidly, then also can double as solution treatment.

In a word, the final annealing in the present invention is optional, if but consider common DI be shaped in plasticity, it is desirable to as far as possible in advance most soleplate be softened.If also consider the plasticity in metal die forming process, then it is desirable to make annealed material or solution treatment material in advance.

When precedence requirement physical strength, providing cold rolling material relative to plasticity.

final cold rolling rate

Final cold rolling rate in enforcement final annealing situation is preferably in the scope of 50 ~ 90%.If final cold rolling rate is within the scope of this, then the average recrystallization grain in the most soleplate after can making annealing reaches 20 ~ 100 μm, makes the value of elongation reach more than 20%, thus can by the appearance surfaces precision work nattily after being shaped.Further preferred final cold rolling rate is the scope of 60 ~ 90%.

On the other hand, final cold rolling rate when making cold rolling material under the prerequisite not implementing final annealing is preferably in the scope of 5 ~ 40%.When DI is shaped, when thinning drawing is processed more, slightly harder than annealed material most soleplate must be provided.If final cold rolling rate is lower than 5%, though then relevant with composition, by being difficult to make the tensile strength of most soleplate to reach more than 90MPa, if final cold rolling rate is more than 40%, though then relevant with composition, the value of the elongation being difficult to make most soleplate is reached more than 5%.

If final cold rolling rate is within the scope of this, then the value of the elongation of cold rolling most soleplate can be made to reach more than 5% and make tensile strength reach more than 90MPa.Further preferred final cold rolling rate is the scope of 10 ~ 30%.

By through common operation as above, secondary cell container aluminium alloy plate can be obtained.

Embodiment

the manufacture of most soleplate

By the various ingot casting meterings of regulation, fusion, in No. 20 crucibles being coated with release materials, insert the ingot casting of filling 6kg (adding up to 8 for examination material) respectively.These crucibles are inserted in electric furnace, melts in 780 DEG C and remove dregs, then melt temperature being held in 760 DEG C, then de-dregs being wrapped in aluminium foil with each 6g of flux, add with phosphorizer (phosphorizer) extruding.

Then, in liquation, spray gun is inserted, by N ₂gas is blown into 10 minutes with the flow of 1.0L/ minute and carries out degassed process.Then, tranquil 30 minutes, remove the dregs floated on molten surface by stirring rod, then with sample spoon, disk sample is taken in composition analysis mould.

Then, with fixture, crucible is taken out successively in electric furnace, cast aluminum liquation in preheated metal die (250mm × 200mm × 30mm).Compositional analysis is carried out to each disk sample emission spectroanalysis for examination material.The results are shown in table 1.

[table 1]

Table 1: the one-tenth for examination material is grouped into

For ingot bar, after rising head is cut off, two sides is respectively carried out to the surfacing cut of 2mm, make thickness reach 26mm.

This ingot bar is inserted in electrical heater, is heated to 430 DEG C with the heat-up rate of 100 DEG C/h, carries out the process that homogenizes of 430 DEG C × 1 hour, then implement hot rolling until thickness reaches 6mm with hot rolls.

Implement cold rolling to this hot-rolled sheet, obtain the cold-reduced sheet that thickness is 1.25mm.This cold-reduced sheet is inserted annealing furnace, keep carrying out process annealing process in 1 hour at 390 DEG C after, annealed sheet is taken out laggard row air cooling from annealing furnace.Then, implement cold rolling to this annealed sheet, obtain the cold-reduced sheet that thickness is 1.0mm.Final cold rolling rate in this situation is 20%.

Cold rolled annealed plate implements cold rolling by not implementing process annealing to above-mentioned hot-rolled sheet, thus the cold-reduced sheet of the 1mm obtained.Final cold rolling rate in this situation is 83.3%.Final annealing is that cold-reduced sheet is inserted annealing furnace, after carrying out anneal, cold-reduced sheet is taken out laggard row air cooling from annealing furnace under the condition of 390 DEG C × 1 hour.

Then, to most soleplate (each for examination material) the forming property of gained thus, the evaluation of laser welding.

the evaluation of plasticity

The plasticity evaluation of the most soleplate of gained is carried out by the elongation (%) of tension test.

Specifically, JIS5 test film is gathered in the mode that draw direction is parallel with rolling direction, carry out tension test according to JISZ2241, calculate tensile strength (UTS), 0.2% yield strength (YS), elongation (elongation at break).

In cold rolling most soleplate, by the value of elongation be more than 5% be designated as plasticity good (zero) for examination material, by lower than 5% be designated as plasticity bad (×) for examination material.Evaluation result is shown in table 2.

Implement after cold rolling in the most soleplate of annealing, by the value of elongation be more than 20% be designated as plasticity good (zero) for examination material, by lower than 20% be designated as plasticity bad (×) for examination material.Evaluation result is shown in table 3.

In addition, in table 3 for examination material number, with each shown in table 1, for examination material number adds the figure place of 10, the numbering that obtains represents.

laser Welding Condition

Pulsed laser irradiation is carried out to the most soleplate of gained, carries out the evaluation of laser welding.Use the YAG laser-beam welding machine JK701 that Lu's this company of nimonic (LUMONICS society) makes; frequency 37.5Hz, welding speed 450mm/ minute, the energy 6.0J of each pulse, shielding gas (nitrogen) flow 1.5 (L/ minute) condition under, to 2 blocks of identical plates for examination material with end each other mode that is very close to each other, that be close to carry out the pulsed laser welding of overall length for 120mm length along this part.

the evaluation of laser welding, the mensuration/evaluation of abnormal bead number

Then, as the evaluation of laser welding, the abnormal bead number that weld part produces is determined at.First, in the welding line that above-mentioned 120mm is long, the welding line that the 60mm of middle body is long is defined as measuring region.Then, as shown in Figure 1, in welding direction with the interval METHOD FOR CONTINUOUS DETERMINATION of 0.05mm along the welding line that 60mm is long formed by the width of the melting bead of the circle of each pulses generation, calculate " the average weld width " of every 10mm long (1 is interval), calculate by " the average weld width " in each interval the number representing and depart from the place of more than 1.1 of bead width, and represent with ratio.This counting of 60mm (6 is interval) part is added, as this for the abnormal bead number trying material.

In present disclosure, the examination material that supplies abnormal bead number being less than 10 is designated as abnormal bead number evaluation good (zero), and the supply examination material of abnormal bead number more than 10 is designated as abnormal bead number evaluation bad (×).The evaluation result of cold rolling material is shown in table 2, the evaluation result of cold rolled annealed plate is shown in table 3.

mensuration/the evaluation of fusion penetration

Then, as the evaluation of laser welding, the fusion penetration of weld part is measured.As shown in Figure 2, cut out the plate cross section on the direction vertical with welding direction, thermoplastic resin imbedded in this plate cross section and carries out mirror ultrafinish, observing the metallographic of weld part vertical cross-section.

During casting, the intermetallic compound of crystallization is heated to high temperature by the heat produced by pulsed laser irradiation, be melted in aluminium, and then, bead will be dissolved and cool rapidly, be solid-solution in the tissue in Al matrix with forming the element supersaturation such as Fe, Mn, the Si forming above-mentioned intermetallic compound.

Therefore, by observing the metallographic of weld part vertical cross-section, the region only having the Al matrix not observing intermetallic compound in this cross section is puddle, by measuring the full depth of this region apart from most endplate surface, can measure fusion penetration.

1 is carried out to the fusion penetration mensuration in 5 cross sections for examination material, its mean value is supplied as this fusion penetration (μm) trying material.In addition, the cross section at now above-mentioned abnormal bead place does not belong to determination object.

In this specification sheets, be that the examination material that supplies of more than 220 μm is designated as fusion penetration evaluation good (zero) by fusion penetration, the examination material that supplies fusion penetration being less than 220 μm is designated as fusion penetration evaluation bad (×).The evaluation result of cold rolling material is shown in table 2, the evaluation result of cold rolled annealed plate is shown in table 3.

[table 2]

Table 2: for the evaluation result (cold rolling material) of examination material

[table 3]

Table 3: for the evaluation result (cold rolled annealed material) of examination material

each evaluation for examination material

Illustrate that the embodiment 1 ~ 4 in the table 2 of the evaluation result of cold rolling material is composition cold rolling materials in compositing range of the present invention, laser welding (abnormal bead number evaluation, fusion penetration evaluation), plasticity are all good (zero).

The Mn content of comparative example 1 is 2.59 up to 1.27 quality %, Mn/Fe ratio and also outside scope of the present invention, although fusion penetration evaluation good (zero), plasticity bad (×), abnormal bead number evaluate bad (×).

The Fe content of comparative example 2 is up to 1.6 quality %, and outside scope of the present invention, although fusion penetration evaluation good (zero), plasticity bad (×), abnormal bead number evaluate bad (×).

Fe, Mn of comparative example 3 ~ 5 are few, and outside scope of the present invention, although plasticity well (zero), abnormal bead number evaluation good (zero), fusion penetration evaluates bad (×).

The Si content of comparative example 6 up to 0.5 quality %, outside scope of the present invention, although fusion penetration evaluation good (zero), abnormal bead number evaluation good (zero), plasticity bad (×).

Illustrate that the embodiment 11 ~ 14 in the table 3 of the evaluation result of cold rolled annealed material is composition annealed materials in compositing range of the present invention, laser welding (abnormal bead number evaluation, fusion penetration evaluation), plasticity are all good (zero).

The Mn content of comparative example 11 is 2.59 up to 1.27 quality %, Mn/Fe ratio and outside scope of the present invention, although fusion penetration evaluation well (zero), plasticity good (zero), abnormal bead number is evaluated as bad (×).

The Fe content of comparative example 12 is up to 1.6 quality %, and outside scope of the present invention, although fusion penetration evaluation good (zero), plasticity bad (×), abnormal bead number evaluate bad (×).

Fe, Mn of comparative example 13 ~ 15 are all few, and outside scope of the present invention, although plasticity well (zero), abnormal bead number evaluation good (zero), fusion penetration evaluates bad (×).

The Si content of comparative example 16 up to 0.5 quality %, outside scope of the present invention, although fusion penetration evaluation good (zero), abnormal bead number evaluation good (zero), plasticity bad (×).

the mensuration of the second phase particles number in metallographic

Cut out the vertical section (with LT direction vertical cross section) parallel with the rolling direction of the most soleplate of gained, thermoplastic resin is imbedded in this vertical section and carries out mirror ultrafinish, observe metallographic.(area in every 1 visual field is 0.0334mm to carry out photograph taking with opticmicroscope to microcosmic metallographic ², 10 visuals field are taken to each sample) and carry out the image analysis of photograph, the equivalent circle diameter measuring per unit area is the second phase particles number of more than 5 μm.Cold rolling material is shown in table 4 by the measurement result of image analysis gained, cold rolled annealed plate is shown in table 5 by the measurement result of image analysis gained.

[table 4]

Table 4: second phase particles number (unit: individual/mm ²) (cold rolling material)

[table 5]

Table 5: second phase particles number (unit: individual/mm ²) (cold rolled annealed material)

Known according to the table 4 of the evaluation result that cold rolling material is shown, the equivalent circle diameter in metallographic is the second phase particles number of more than 5 μm is 500/mm ²when above (comparative example 2,6), in tension test, the interface between thicker second phase particles and matrix is easily separated, so the value of elongation diminishes as lower than 5%.

Therefore, in the present invention known, in order to make the value of elongation reach more than 5%, the equivalent circle diameter in metallographic must be made to be that the second phase particles number of more than 5 μm is less than 500/mm ².

Known according to the table 5 of the evaluation result that cold rolled annealed material is shown, the equivalent circle diameter in metallographic is the second phase particles number of more than 5 μm is 500/mm ²when above (comparative example 12,16), in tension test, the interface between thicker second phase particles and matrix is easily separated, and therefore the value of elongation diminishes as lower than 20%.

Therefore, known in order to make the value of elongation reach more than 20%, the equivalent circle diameter in metallographic must be made to be that the second phase particles number of more than 5 μm is less than 500/mm ².

The possibility that industry utilizes

According to the present invention, the high strength having and can be used for large-scale lithium ion battery container can be provided, and have excellent formability, Al-Fe line aluminium alloy plate that laser welding is also excellent.

Claims

1. an aluminium alloy plate for battery case for plasticity and welding property excellent, is characterized in that,

It is the cold rolling material of the value of the elongation with more than 5% and the tensile strength of more than 90MPa,

And there is following chemical constitution: the Zr of the Mn of the Fe containing 0.3 ~ 1.5 quality %, 0.3 ~ 1.0 quality %, the Ti of 0.002 ~ 0.20 quality %, 0.05 ~ 0.2 quality %, the mass ratio of Mn/Fe is 0.2 ~ 1.0, rest part is made up of Al and impurity, as impurity, be that Si is less than 0.30 quality %, Cu is less than 0.20 quality %, Mg is less than 0.20 quality % respectively;

And having equivalent circle diameter is that the second phase particles number of more than 5 μm is less than 500/mm ²metallographic.

2. an aluminium alloy plate for battery case for plasticity and welding property excellent, is characterized in that,

It is the cold rolled annealed material of the value of the elongation with more than 20%,

And there is following chemical constitution: the Zr of the Mn of the Fe containing 0.3 ~ 1.5 quality %, 0.3 ~ 1.0 quality %, the Ti of 0.002 ~ 0.20 quality %, 0.05 ~ 0.2 quality %, the mass ratio of Mn/Fe is 0.2 ~ 1.0, rest part is made up of Al and impurity, as impurity, be that Si is less than 0.30 quality, Cu is less than 0.20 quality %, Mg is less than 0.20 quality % respectively;