JP2007073402A - Aluminum laminate structure for battery housing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aluminum laminate structure for a battery housing superior in molding characteristics, gas barrier characteristics, heat sealing property, and electrolytic solution resistance. <P>SOLUTION: The aluminum laminate structure for the battery sheath is formed by successively laminating an innermost layer 2, a first adhesive layer 3, a first surface treatment layer 4, an aluminum foil layer 5, a second surface treatment layer 6, a second adhesive layer 7, and an outermost layer 8 from inside. The aluminum foil layer 5 is composed of an aluminum alloy in which the alloy component is Fe: 0.8 wt.% to 2.0 wt.%, Si: 0.2 wt.% or less, and Mn: 0.1 wt.% or less. The first surface treatment layer 4 and the second surface treatment layer 6 are composed of an inorganic element containing resin film or a thermoplastic resin film containing the inorganic element and a water soluble acrylic resin. The first adhesive layer 3 and the second adhesive layer 7 are composed of a urethane based adhesive. The innermost layer 2 is composed of a non-stretched thermoplastic resin film, and the outermost layer 8 is composed of a stretched thermoplastic resin film. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an aluminum laminate composition used for the exterior of a battery such as a lithium ion polymer battery.

Batteries such as lithium ion secondary batteries used in portable electronic devices such as mobile phones, electronic notebooks, notebook computers, and video cameras are required to be thinner and lighter.
Among lithium ion secondary batteries, a battery using a solid or semi-solid electrolyte such as a conductive polymer is called a polymer battery. This polymer battery is an electrolysis obtained by adding a complex fluoride such as LiBF ₄ or LiPF ₆ to a solvent such as PC (propylene carbonate), EC (ethylene carbonate), DEC (diethyl carbonate), or γ-BL (gamma butyrolactone). Compared to ordinary lithium ion secondary batteries using liquid, the battery can be made thinner and lighter, there is less risk of electrolyte leakage, etc., and it is excellent in terms of safety. Spread is promising.

As a case for an exterior of a polymer battery, a case in which a packaging material formed from a composite aluminum foil obtained by bonding a thermoplastic resin such as polypropylene to an aluminum foil by heat lamination has been conventionally used.
In the conductive polymer, the electrolyte solution obtained by adding the complex fluoride to the solvent is used. The complex fluoride in the electrolyte solution, water adsorbed on the surface of the electrode or the packaging material, gas barrier property There is a possibility that hydrogen fluoride (HF) may be generated by reaction with water that has permeated through a low exterior case and entered from the outside. This hydrogen fluoride is likely to penetrate the thermoplastic resin layer and corrode the aluminum foil in the conventional exterior case made of the composite aluminum foil composed of the thermoplastic resin layer and the aluminum foil layer. There is. As a result, the adhesiveness between the aluminum foil and the thermoplastic resin layer was lowered, and the thermoplastic resin layer might be peeled off. Accordingly, an exterior case that is more excellent in gas barrier properties and electrolytic solution resistance is desired.

  In the polymer battery, the exterior case is heat-sealed. If the adhesiveness of the heat-sealed portion is insufficient, generally an electrolyte containing fluoride may leak out. Therefore, the exterior case is desired to have excellent heat sealability that can exhibit excellent adhesion by heat sealing.

  In recent years, there has been an increasing demand for portable electronic devices with higher performance, smaller size and lighter weight, and cost reduction, and both improvement in heat sealability, moldability, gas barrier properties, and electrolyte resistance and reduction in thickness and weight have been achieved. It is desired. However, the conventional exterior case made of the composite aluminum foil has a high coefficient of friction, and if the follow-up to the mold during molding is poor, cracking may occur during molding, and the moldability is insufficient. In addition, when the thickness is reduced, the strength is lowered and the risk of pinholes occurring in the aluminum foil is increased, which causes a decrease in yield.

  In addition, in order to improve electrolytic solution resistance, heat sealability, etc., a polymer battery packaging material consisting of a composite aluminum foil laminated in the order of aluminum foil, maleic anhydride-modified polypropylene layer, and extrusion-coated polypropylene layer was developed. (See Patent Document 1). Further, a composite packaging material for a polymer battery has been developed, which is composed of a composite aluminum foil in which an aluminum foil, a surface treatment layer containing metal, a maleic anhydride-modified polypropylene layer, and a thermoplastic resin layer are laminated in this order (Patent Document 2). reference).

  However, the extrusion-coated polypropylene layer formed by the extrusion coating method has a problem that it is inefficient and unsuitable for multi-product lot production with frequent changes in line specifications. Further, in the conventional polymer battery packaging material and polymer battery composite packaging material, it has been difficult to improve all the required characteristics of moldability, gas barrier property, heat sealability, and electrolytic solution resistance.

JP 2001-102011 A JP 2002-75298 A

  The present invention has been made in view of such conventional problems, and is intended to provide an aluminum laminate composition for battery exterior that is excellent in moldability, gas barrier properties, heat sealability, and electrolyte resistance. It is.

The present invention is an aluminum laminate composition for battery exterior having a total thickness of 250 μm or less used for battery exterior,
In the aluminum laminate composition for battery exterior, from the inside, an innermost layer made of an unstretched thermoplastic resin film having a thickness of 10 to 100 μm and a first adhesive layer made of a urethane-based adhesive having an adhesion amount of 1 to 10 g / m ² And an inorganic element resin film or polypropylene resin, polyethylene resin, acrylic resin, ionomer resin, and epoxy containing one or more inorganic elements selected from zirconium, titanium, zinc, chromium, and silicon and a water-soluble acrylic resin A first surface treatment layer made of one or more kinds of resins selected from resins and made of a thermoplastic resin film having a thickness of 1 to 10 μm; an aluminum foil layer made of an aluminum alloy and having a thickness of 10 to 100 μm; and the inorganic element-containing resin film Or the 2nd surface treatment layer which consists of the said thermoplastic resin membrane | film | coat, and urethane of the adhesion amount 1-10 g / m < ² > A second adhesive layer made of an adhesive and an outermost layer made of a stretched thermoplastic resin film having a thickness of 10 to 50 μm and a friction coefficient of 0.35 or less are sequentially laminated,
In the aluminum alloy of the aluminum foil layer, the alloy components are Fe: 0.8 mass% to 2.0 mass%, Si: 0.2 mass% or less, Mn: 0.1 mass% or less, and the balance is Consisting of aluminum and inevitable impurities,
Among the inorganic elements in the inorganic element-containing resin film, the amount of the inorganic element having the largest amount of adhesion is 1 to 100 mg / m ² in the aluminum laminate composition for battery exterior, characterized in that 1).

  In the aluminum laminate composition for battery exterior of the present invention, the innermost layer, the first adhesive layer, the first surface treatment layer, the aluminum foil layer, the second surface treatment layer, the second adhesive layer from the inside, And the said outermost layer is laminated | stacked one by one. Thus, since a specific layer is laminated | stacked one by one, the said aluminum laminated structure for battery exteriors can show the outstanding moldability, gas barrier property, heat seal property, and electrolyte solution resistance.

Next, a preferred embodiment of the present invention will be described.
The aluminum laminate composition for battery exterior includes the innermost layer, the first adhesive layer, the first surface treatment layer, the aluminum foil layer, the second surface treatment layer, the second adhesive layer, and the innermost layer from the inside. The outer layer is laminated.

The above-mentioned aluminum laminate for battery exterior wraps the battery components such as a positive electrode, a negative electrode, a separator, and a solid or semi-solid electrolyte with the innermost layer inside, and heat-seal the innermost layers, for example. Can be used by wearing.
In the battery exterior aluminum laminate composition, for example, the first surface treatment layer and the second surface treatment layer are formed so as to sandwich the aluminum foil layer, and the first adhesive layer is formed on the first surface treatment layer. Further, the innermost layer is laminated on the first adhesive layer, while the second adhesive layer is laminated on the second surface treatment layer, and the above-mentioned second adhesive layer is laminated on the second adhesive layer. The outermost layer can be formed by stacking.

The aluminum foil layer is made of an aluminum alloy. The aluminum alloy has alloy components of Fe: 0.8 mass% to 2.0 mass%, Si: 0.2 mass% or less, Mn: 0.1 mass% or less. And the balance consists of aluminum and inevitable impurities.
When Fe is less than 0.8% by mass, the amount of intermetallic compounds formed in aluminum decreases, and the strength may be insufficient. On the other hand, if it exceeds 2.0% by mass, a coarse intermetallic compound is formed, the mechanical properties of the aluminum foil layer are lowered, and pinholes are easily generated when the aluminum foil layer is produced. There is a risk of becoming.

  Further, when Si exceeds 0.2% by mass, spherical Al—Fe—Si intermetallic compounds are formed during casting, and pinholes are likely to be generated by the intermetallic compounds. Further, solute Si tends to cause non-uniform deformation during rolling, and as a result, pinholes are likely to be generated. Moreover, when Mn exceeds 0.1 mass%, the Al-Fe-Mn-based metal compound generated during the production of the aluminum foil layer itself becomes coarse, and pinholes are likely to be generated. .

The aluminum foil layer has a thickness of 10 to 100 μm.
When the thickness of the aluminum foil layer is less than 10 μm, the strength of the battery laminate aluminum laminate composition may be reduced. Moreover, there exists a possibility that a moldability may fall. On the other hand, if it exceeds 100 μm, the moldability may be reduced. Moreover, there exists a possibility that heat conductivity may fall and heat seal property may deteriorate. Furthermore, the weight of the above-described aluminum laminate composition for battery exterior increases, and there is a risk of increasing the cost.

In the battery laminate aluminum laminate composition, the aluminum foil layer has the first surface treatment layer formed on one surface and the second surface treatment layer formed on the other surface. The first surface treatment layer can prevent the aluminum foil layer from being corroded by the electrolytic solution and peeling off the aluminum foil layer and the inner layer. The second surface treatment layer can improve the adhesion between the aluminum foil layer and the outer layer, and can prevent peeling during molding.
The first surface treatment layer and the second surface treatment layer are made of the inorganic-containing element resin film or the thermoplastic resin film.
The inorganic-containing element resin film contains one or more inorganic elements selected from zirconium, titanium, zinc, chromium, and silicon, and a water-soluble acrylic resin. In the inorganic-containing element resin film, The adhesion amount of the inorganic element having the largest adhesion amount is 1 to 100 mg / m ² .

In the inorganic element-containing resin film, when the adhesion amount of the most inorganic element is less than 1 mg / m ² , the adhesion between the aluminum foil layer and the innermost layer or the outermost layer may be insufficient. . As a result, there is a possibility that the moldability is lowered or the gas barrier property is lowered due to the intrusion of water vapor. On the other hand, if it exceeds 100 mg / m ² , moldability may be reduced. Further, when the adhesion amount exceeds 50 mg / m ² , the performance improvement effect is hardly recognized, and it is necessary to perform, for example, a plurality of coatings in order to form the inorganic-containing resin film, resulting in an increase in cost. May be incurred. Therefore, more preferably, the adhesion amount is 1 to 50 mg / m ² .

Moreover, it is preferable that the adhesion amount of the said inorganic element in the said inorganic-containing element resin film is 100 mg / m < ² > or less in a total amount (Claim 2).
If the total amount of inorganic elements exceeds 100 mg / m ² , the moldability may be reduced.

The thermoplastic resin film is made of at least one resin selected from polypropylene resin, polyethylene resin, acrylic resin, ionomer resin, and epoxy resin. The thermoplastic resin film preferably has a thickness of 1 to 10 μm.
When the thickness of the thermoplastic resin film is less than 1 μm, the adhesiveness with the innermost layer or the outermost layer is lowered, and the moldability and gas barrier property may be lowered. On the other hand, if it exceeds 10 μm, the moldability may be reduced.

  The first surface treatment layer and the second surface treatment layer can be formed by performing a surface treatment on the aluminum foil layer. A preferred surface treatment is a coating type treatment. In the coating-type process, there is an advantage that it is not necessary to provide a reaction tank as in the reactive chemical conversion process, and the process can be performed by applying a dry laminate line. As a coating method, a gravure coating method is preferable from the viewpoint of mass productivity, but a roll coating method, a curtain flow method, a dipping method, and the like can also be applied.

When the inorganic element-containing resin film is formed as the first surface treatment layer and the second surface treatment layer, in the coating type treatment, for example, one kind selected from zirconium, titanium, zinc, chromium, and silicon A coating-type surface treatment agent containing the above inorganic element salt and a water-soluble acrylic resin can be used. The coating type surface treatment agent can be prepared by combining a reducing agent, an inorganic acid, an organic compound, and the like in addition to the salt of the inorganic element and the water-soluble acrylic resin. Further, in order to improve the corrosion resistance, vapor phase silica particles can be contained. Examples of the inorganic element salt include chromate, zirconium, titanium, silicon fluoride salts (ZrF ₄ ²⁻ , TiF ₆ ²⁻ , SiF ₆ ²⁻ ), silicates, and the like. As the reducing agent, organic compounds having a hydroxyl group such as alcohols and polysaccharides can be used. Specific examples include tannic acid, methanol, hydrazine, and sucrose. Examples of inorganic acids include phosphoric acid, hydrofluoric acid, and silicic acid. Examples of the organic compound include polyacrylic acid, polymethacrylic acid, acrylic acid, a copolymer of methacrylic acid, cellulose, and polyvinyl alcohol.

The first adhesive layer and the second adhesive layer are made of a urethane adhesive having an adhesion amount of 1 to 10 g / m ² .
When the adhesion amount of the urethane-based adhesive is less than 1 g / m ² , the adhesive strength is lowered and the moldability may be lowered. On the other hand, if it exceeds 10 g / m ² , cohesive failure tends to occur in the adhesive layer during molding, and the moldability may be reduced.
The first adhesive layer and the second adhesive layer can be formed by applying a urethane-based adhesive to the aluminum foil layer on which the first surface treatment layer and the second surface treatment layer are formed.

Next, the innermost layer is made of an unstretched thermoplastic resin film having a thickness of 10 to 100 μm.
When the thickness of the innermost layer is less than 10 μm, when the innermost layers are heat-sealed by heat sealing, the strength of the fused portion becomes insufficient, and for example, electrolyte solution may leak from the fused portion. is there. On the other hand, when it exceeds 100 μm, it becomes difficult to perform heat sealing and heat-sealing, and there is a possibility that the heat-sealing property is lowered.

The unstretched thermoplastic resin film is preferably an unstretched film made of one or more resins selected from polypropylene resins, polyethylene resins, and ionomer resins.
In this case, the heat seal property of the innermost layer can be further improved, and the gas barrier property can be further improved.

The outermost layer is made of a stretched thermoplastic resin film having a thickness of 10 to 50 μm and a friction coefficient of 0.35 or less.
If the thickness of the outermost layer is less than 10 μm, the moldability may be reduced. On the other hand, when it exceeds 50 μm, it is difficult to sufficiently transfer heat to the innermost layer at the time of heat sealing, and the heat sealing property may be deteriorated. Moreover, when a friction coefficient exceeds 0.35, followable | trackability to a metal mold | die will worsen and there exists a possibility that a moldability may fall.

The stretched thermoplastic resin film is preferably a stretched film made of one or more resins selected from nylon resin, polyethylene terephthalate resin, and polypropylene resin.
In this case, mechanical strength and workability can be improved.

The total thickness of the battery exterior aluminum laminate composition is 250 μm or less. When total thickness exceeds 250 micrometers, there exists a possibility that heat sealing property may fall.
The total thickness is the thickness of the entire aluminum laminate composition for battery exterior composed of a laminate of a plurality of layers. For example, the innermost layer, the first adhesive layer, the first constituting the aluminum laminate composition for battery exterior It is the sum total of the thickness of each layer, such as a surface treatment layer, an aluminum foil layer, a 2nd surface treatment layer, a 2nd contact bonding layer, and an outermost layer. The total thickness of the aluminum laminate composition for battery exterior is, for example, the thickness of each layer of the aluminum foil layer, the first surface treatment layer, the second surface treatment layer, the innermost layer, and the outermost layer, It can adjust by adjusting the adhesion amount of a surface treatment layer, the said 2nd surface treatment layer, the said 1st contact bonding layer, and the said 2nd contact bonding layer.

  Moreover, the said aluminum laminated structure for battery exteriors can be used as a case for battery exteriors. The said aluminum laminated structure for battery exteriors can accommodate battery components, such as a positive electrode, a negative electrode, and an electrolyte, by fuse | melting the innermost layers by heat sealing.

Example 1
Next, a battery exterior aluminum laminate composition according to an embodiment of the present invention will be described with reference to FIGS. In addition, this invention is not limited only to these Examples.
In this example, 27 types of aluminum laminate components (sample E1 to sample E27) were produced as examples of the present invention, and 22 types of aluminum laminate components (sample C1 to sample C22) were produced as comparative examples. A test for evaluating the characteristics was conducted.

As shown in FIG. 1, the battery laminate aluminum laminate composition 1 of sample E1 is a battery exterior aluminum laminate composition 1 having a total thickness of 250 μm or less used for the battery exterior.
In the sample E1, the innermost layer 2, the first adhesive layer 3, the first surface treatment layer 4, the aluminum foil layer 5, the second surface treatment layer 6, the second adhesive layer 7 and the outermost layer are arranged from the inside. 8 are sequentially stacked. Samples E2 to E27 and Samples C1 to C22 are basically aluminum laminate structures having the same laminated structure as Sample E1.

The aluminum laminate composition for battery exterior 1 is used for a battery case that sheathes a positive electrode 91, a negative electrode 92, a separator, and a battery composition 9 such as a solid or semi-solid electrolyte.
In the case of producing a battery using the aluminum laminate composition 1 for battery exterior, for example, the battery composition 9 such as the positive electrode 91, the negative electrode 92, the separator, and the solid or semi-solid electrolyte is replaced with two pieces of the aluminum laminate composition 1. Thus, the innermost layer 2 side can be sandwiched and sealed by heat sealing. In the heat seal, at least the innermost layers 2 are partially heat-sealed to form the fused portion 25. (See FIGS. 2 to 4).

As shown in FIG. 1, in the aluminum laminate composition 1 for battery exterior of samples E1 to E27, the innermost layer 2 is made of an unstretched thermoplastic resin film having a thickness of 10 to 100 μm. Moreover, the 1st contact bonding layer 3 and the 2nd contact bonding layer 7 consist of urethane type adhesive agents with the adhesion amount of 1-10 g / m < ² >. The first surface treatment layer 4 and the second surface treatment layer 6 are made of an inorganic element resin film or a thermoplastic resin film. The inorganic element-containing resin film contains one or more inorganic elements selected from zirconium, titanium, zinc, chromium, and silicon and a water-soluble acrylic resin. The thermoplastic resin film has a thickness of 1 to 10 μm and is made of one or more resins selected from polypropylene resin, polyethylene resin, acrylic resin, ionomer resin, and epoxy resin. The aluminum foil layer 5 has a thickness of 10 to 100 μm and is made of an aluminum alloy. The outermost layer 8 is made of a stretched thermoplastic resin film having a thickness of 10 to 50 μm and a friction coefficient of 0.35 or less. Moreover, the total thickness of the aluminum laminate constituent for battery exterior of each sample is 250 micrometers or less.

Moreover, in the aluminum alloy of the aluminum foil layer 5, the alloy components are Fe: 0.8 mass% to 2.0 mass%, Si: 0.2 mass% or less, Mn: 0.1 mass% or less, and the balance Consists of aluminum and inevitable impurities. Moreover, the adhesion amount of the inorganic element having the largest adhesion amount among the inorganic elements in the inorganic-containing element resin film is 1 to 100 mg / m ² .
Moreover, the aluminum laminate structure of Samples C1 to C22 has a part whose structure deviates from the preferred range in the present invention.

Tables 1 to 5 show the material, thickness, total thickness, and the like of each layer constituting each sample (sample E1 to sample E27 and sample C1 to sample C22).
Briefly, as the outermost layer 8, one of stretched or unstretched Ny (nylon film), PET (polyethylene terephthalate film), and PP (polypropylene film) was employed.
The 1st contact bonding layer 3 and the 2nd contact bonding layer 7 were produced using the urethane type adhesive agent (U) or the phenol type adhesive agent (PF).

  As the first surface treatment layer 4, an inorganic element resin film was used, and as the second surface treatment layer 6, an inorganic element resin film or a thermoplastic resin film was used. The inorganic element-containing resin film was formed by applying a water-soluble acrylic resin and a surface treatment agent containing a Zr salt or a Cr salt to the aluminum foil layer 5. As the thermoplastic resin film, a polypropylene film (PP), a polyethylene film (PE), an acrylic film (ACR), an ionomer film (IO), or an epoxy film (EP) was employed. In addition, when the said inorganic-containing element resin film is used as a 1st surface treatment layer or a 2nd surface treatment layer, the kind of inorganic element and its adhesion amount are shown to Tables 1-5. Further, when a thermoplastic resin film is used as the second surface treatment layer 6, the thicknesses are shown in Tables 1 to 5.

As the aluminum foil layer 5, a layer made of an aluminum alloy containing Fe, Si, and Mn as an alloy component was employed. Tables 1 to 5 show the composition of the alloy components of the aluminum foil layer 5 in each sample.
Further, as the innermost layer 2, any one of an unstretched or stretched polypropylene film (PP), a polyethylene film (PE), an ionomer film (IO), or a nylon film (Ny) was employed.

Next, a method of manufacturing the aluminum laminate constituent for battery exterior of sample E1 will be briefly described.
First, a coating type surface treatment agent containing a Zr salt and a water-soluble acrylic resin is applied to the inner side surface of the aluminum foil layer 5 to form a first surface treatment layer. A coating-type surface treatment agent containing a functional acrylic resin was applied to form a second surface treatment layer. In forming the first surface treatment layer and the second surface treatment layer, the adhesion amount of the inorganic element (Zr) was adjusted to 20 mg / m ² .

Next, a urethane adhesive is applied to the first surface treatment layer and dried to form the first adhesive layer 3, and an unstretched polypropylene film is pressure-bonded onto the first adhesive layer 3 to form the innermost layer 2. did.
In addition, a urethane adhesive was applied to the second surface treatment layer and dried to form the second adhesive layer 7. A stretched nylon film was pressure-bonded onto the second adhesive layer 7 to form the outermost layer 8.
In this way, an aluminum laminate composition for battery exterior (sample E1) was produced.
Further, the aluminum laminate components of the other samples E2 to E27 and Samples C1 to C22 were basically manufactured in the same manner as the sample E1 except for the changes in thickness, material, and the like.

  Next, the friction coefficient of the outermost layer was measured for the aluminum laminate composition for battery exterior of each sample (sample E1 to sample E27 and sample C1 to sample C22) produced as described above. Each sample was evaluated for formability, gas barrier properties, heat sealability, and electrolyte resistance.

(Coefficient of friction)
The coefficient of friction was measured by a method of sliding a rigid sphere having a diameter of 12 mm in a three-point ball type slip tester friction test with a load of 200 g. The results are shown in Tables 1-5.

(Formability)
Each sample was cut into a blank shape of 100 mm × 75 mm, a mold having a molding height free and a punch shape having a long side: 62 mm, a short side: 34 mm, a corner R: 1-2 mm, a punch shoulder 1 mm, and a die shoulder R: 1 mm Was subjected to overhanging (one-step overhanging molding). The quality of the moldability was judged based on the molding height after molding. Judgment criteria are: ◎ when the limit molding height is 5 mm or more, ◯ when 4 mm or more and less than 5 mm, △ when 2 mm or more and less than 4 mm, and X when less than 2 mm. Tables 1 to 5 show.

(Gas barrier properties)
For each sample, prepare two sheets of aluminum laminate composition for battery outer packaging, paste them together with the innermost layer as the inner surface, and heat seal the three sides to make a bag made of aluminum laminate composition for battery outer packaging. Into this, 3 g of a mixed solution of ethylene carbonate and propylene carbonate is poured, and the remaining one is heat sealed to seal the mixed solution in a bag. This sample was stored in an atmosphere at a temperature of 80 ° C. and a humidity of 90% for 3 days, and the moisture content before and after storage was measured with a Karl Fischer moisture meter. The case where the amount of increase in moisture before and after storage is less than 300 ppm is indicated by ◎, the case of 300 ppm or more and less than 600 ppm is indicated by ◯, the case of 600 ppm or more and less than 900 ppm is indicated by △, and the case of 900 ppm or more is indicated by ×. did. The results are shown in Tables 1-5.

(Heat sealability)
Regarding the aluminum laminate composition for battery exterior of each sample, two aluminum laminate structures are laminated with the innermost layer side as the inner surface, and bonded by heat sealing at a temperature of 190 ° C., and the time required for bonding is measured. did.
When the heat seal time is less than 0.5 seconds, when it is less than 1 second, when it is less than 1 second, when it is less than 2 seconds, when it is less than 2 seconds, when it is not bonded even after heat sealing Is represented by a cross. The results are shown in Tables 1-5.

(Electrolytic solution resistance)
For each sample, a bag was prepared by heat-sealing three sides of the two aluminum laminate components for battery exterior that were bonded together with the innermost layer as the inner surface, and 3 g of the electrolyte was injected therein. As the electrolytic solution, a solution in which LiPF ₆ was dissolved at a concentration of 1 M in a mixed solution of ethylene carbonate and propylene carbonate was used. Next, the remaining one (opening portion of the bag) is heat sealed to seal the electrolyte in the bag. This sample was kept in an atmosphere at a temperature of 80 ° C. for 5 hours, and then the presence or absence of peeling between each layer of the aluminum laminate composition was visually observed. A case where there was no peeling was indicated by a circle, and a case where there was peeling was indicated by a x. The results are shown in Tables 1-5.

As is known from Tables 1 to 3, the battery laminate aluminum laminate composition of Samples E1 to E27 was excellent in all of moldability, gas barrier property, heat lease property, and electrolytic solution resistance.
On the other hand, in Sample C1, the thickness of the outermost layer was too small and the moldability was insufficient.
In Sample C2, the thickness of the outermost layer was too large, heat was hardly transferred during heat sealing, and the heat sealing property was insufficient.
In sample C3, an unstretched nylon film was used for the outermost layer. In this case, necking occurred in the aluminum foil layer during molding, and the moldability was insufficient.
In Sample C4, since the friction coefficient of the outermost layer was too high, the followability to the mold was poor, and the moldability was insufficient.

In sample C5, since the second adhesive layer was formed using a phenol-based adhesive, the adhesiveness was insufficient and the moldability was reduced.
In sample C6, the amount of the second adhesive layer was too small to obtain sufficient adhesive strength, and as a result, moldability was reduced.
In Sample C7, the amount of the second adhesive layer was too large, causing cohesive failure in the second adhesive layer, resulting in a decrease in moldability.

In sample C8, the amount of inorganic element (Zr) attached to the second surface treatment layer was too small, the adhesion between the aluminum foil layer and the outermost layer was insufficient, and the moldability was insufficient. Further, water vapor entered from the insufficiently bonded part, and the gas barrier property was insufficient.
In sample C9, since the thickness of the aluminum foil layer was too small, the strength was insufficient and the moldability was insufficient.
In sample C10, since the aluminum foil layer was too thick, necking occurred during molding, and the moldability was insufficient. Moreover, heat conductivity fell and heat sealability was inadequate.

Although sample C11 was excellent in formability, gas barrier property, heat sealability, and electrolyte solution resistance, the strength decreased because Fe in the aluminum alloy in the aluminum foil layer was too small. Therefore, it is not suitable as an aluminum laminate composition for exterior of a small and lightweight secondary battery.
In sample C12, the aluminum alloy of the aluminum foil layer contained too much Fe, and the formability was insufficient.
In sample C13, too much Si was contained in the aluminum alloy of the aluminum foil layer, and the formability was still insufficient.
In sample C14, too much Mn was contained in the aluminum alloy of the aluminum foil layer, and the formability was still insufficient.

In sample C15, since the first adhesive layer was made of a phenol-based adhesive, the adhesiveness was insufficient and the moldability was insufficient.
In sample C16, the amount of the first adhesive layer was too small and the adhesiveness was insufficient. As a result, the moldability was insufficient. Furthermore, water vapor easily enters due to insufficient adhesion, and gas barrier properties are insufficient.
In sample C17, the amount of the first adhesive layer was too large, and cohesive failure occurred in the first adhesive layer, resulting in a decrease in moldability. Moreover, the heat sealability was also insufficient.

In sample C18, the amount of inorganic element (Zr) attached to the first surface treatment layer was too small, the adhesion between the aluminum foil layer and the innermost layer was insufficient, and the moldability was insufficient. Further, corrosion due to the electrolytic solution occurred from the insufficiently bonded portion, and peeling was likely to occur, and the electrolytic solution resistance was insufficient.
Sample C19 was excellent in moldability, gas barrier properties, heat sealability, and electrolytic solution resistance, but the innermost layer was too thin and the heat seal strength was insufficient. Therefore, there is a possibility that the fusion by heat sealing is destroyed by a small impact or the like, and the electrolyte or the like leaks out.
In sample C20, the thickness of the innermost layer was too large, and the heat sealability was insufficient.

Sample C21 uses a stretched polypropylene film for the innermost layer, but in this case, the heat sealability was poor and the gas barrier property was insufficient. Furthermore, the moldability was insufficient.
Sample C22 had a total thickness that was too large to provide sufficient heat sealability.

Sample E25 can exhibit excellent moldability, gas barrier properties, heat sealability, and electrolytic solution resistance, but a large amount of inorganic element (Zr) of 60 mg / m ² is adhered to the second surface treatment layer. . Therefore, it is necessary to perform coating several times when forming the second surface treatment layer, which may increase manufacturing costs. Furthermore, even when many inorganic elements of 60 mg / m ² were deposited, the characteristics were hardly improved.
In sample E26, a large amount of inorganic element (Zr) of 60 mg / m ² is adhered to the first surface treatment layer. Also in this case, like the sample E26, the manufacturing cost was increased and the characteristics were hardly improved.
Therefore, the adhesion amount of the inorganic element in the first surface treatment layer and the second surface treatment layer is more preferably 50 mg / m ² or less.

  As mentioned above, it turns out that the aluminum laminate composition for battery exteriors (Example E1-Sample E27) concerning the Example of this invention is excellent in a moldability, gas barrier property, heat seal property, and electrolyte solution resistance. .

BRIEF DESCRIPTION OF THE DRAWINGS Explanatory drawing which shows the cross section of the aluminum laminated structure for battery exterior concerning Example 1. FIG. Explanatory drawing which shows the whole battery (polymer battery) concerning an Example. FIG. 3 is a cross-sectional view taken along line AA in FIG. 2. FIG. 4 is an enlarged explanatory view of a fusion part in FIG. 3.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Aluminum laminated structure for battery exterior 2 Innermost layer 3 1st contact bonding layer 4 1st surface treatment layer 5 Aluminum foil layer 6 2nd surface treatment layer 7 2nd contact bonding layer 8 Outermost layer

Claims (4)

An aluminum laminate composition for battery exterior having a total thickness of 250 μm or less used for battery exterior,
In the aluminum laminate composition for battery exterior, from the inside, an innermost layer made of an unstretched thermoplastic resin film having a thickness of 10 to 100 μm and a first adhesive layer made of a urethane-based adhesive having an adhesion amount of 1 to 10 g / m ² And an inorganic element resin film or polypropylene resin, polyethylene resin, acrylic resin, ionomer resin, and epoxy containing one or more inorganic elements selected from zirconium, titanium, zinc, chromium, and silicon and a water-soluble acrylic resin A first surface treatment layer made of one or more kinds of resins selected from resins and made of a thermoplastic resin film having a thickness of 1 to 10 μm; an aluminum foil layer made of an aluminum alloy and having a thickness of 10 to 100 μm; and the inorganic element-containing resin film Or the 2nd surface treatment layer which consists of the said thermoplastic resin membrane | film | coat, and urethane of the adhesion amount 1-10 g / m < ² > A second adhesive layer made of an adhesive and an outermost layer made of a stretched thermoplastic resin film having a thickness of 10 to 50 μm and a friction coefficient of 0.35 or less are sequentially laminated,
In the aluminum alloy of the aluminum foil layer, the alloy components are Fe: 0.8 mass% to 2.0 mass%, Si: 0.2 mass% or less, Mn: 0.1 mass% or less, and the balance is Consisting of aluminum and inevitable impurities,
Among the inorganic elements in the inorganic element-containing resin film, the adhesion amount of the inorganic element having the largest adhesion amount is 1 to 100 mg / m ² . ^{2. The} aluminum laminate composition for battery exterior according to claim 1, wherein a total amount of the inorganic elements attached to the inorganic-containing element resin film is 100 mg / m ² or less.   3. The battery exterior aluminum according to claim 1, wherein the unstretched thermoplastic resin film is an unstretched film made of one or more resins selected from a polypropylene resin, a polyethylene resin, and an ionomer resin. Laminate composition.   The stretched thermoplastic resin film according to any one of claims 1 to 3, wherein the stretched thermoplastic resin film is a stretched film made of one or more resins selected from a nylon resin, a polyethylene terephthalate resin, and a polypropylene resin. Aluminum laminate composition for battery exterior.

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