JP2012216509A - Aluminum foil laminate sheet for secondary battery exterior material and secondary battery exterior material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aluminum foil laminate sheet for a secondary battery exterior material having excellent vibration resistance, adhesion, electrolytic solution resistance and moldability, and being used as the material of container or exterior material of a secondary battery, and to provide a secondary battery exterior material using the same.SOLUTION: In the aluminum foil laminate sheet for the secondary battery exterior material, an aluminum foil (A), a modified polyolefin layer (B), and a non-stretched polypropylene film (C) are laminated in this order. At least the B side surface of the A is subjected to surface roughening, a spongy cavity is formed continuously from the outermost surface thus roughened in the thickness direction, the B layer resin penetrates into the cavity, and the maximum penetration depth is 1-7 μm or more.

Description

  TECHNICAL FIELD The present invention relates to a laminate material used for a secondary battery exterior material, and more particularly to an aluminum foil laminate sheet excellent in adhesion and electrolyte solution resistance used as a secondary battery exterior material, and a secondary battery exterior material using the same. .

  The introduction of electric vehicles, hybrid vehicles, electric motorcycles, etc. has been promoted against the background of the increasing environmental protection movement. For these, utilization of lithium ion secondary batteries is progressing.

  In the lithium ion secondary battery, an exterior material for maintaining the shape of the battery and protecting and maintaining the battery function plays an important role. A laminate material using an aluminum foil as a barrier material is being used for an exterior material for a lithium ion secondary battery.

  The required performance for laminated sheets for lithium ion battery exterior materials is (1) extremely low water vapor transmission rate, (2) leakage of internal electrolyte over time after bag making and injection of electrolyte into the interior. (3) Excellent anti-electrolyte properties, no detachment of constituent materials after a lapse of time, (4) Can be press-molded, and cannot have pinholes or cracks in the aluminum foil after molding, (5) After molding, There are no cracks in the constituent materials, there is no electrical connection between the lead wire and the aluminum foil in the laminate during battery creation, and (6) heat resistance that temporarily withstands a high temperature of about 110 ° C. .

  As a laminated sheet that satisfies these requirements, Patent Document 1 discloses a laminated material in which an exterior resin film / first adhesive layer / chemical conversion treatment aluminum foil / second adhesive layer / sealant film are laminated, Is made of a chromium compound, and the second adhesive layer is an epoxy-containing polyester polyurethane-based laminate.

  Patent Document 2 discloses a laminated material in which an exterior resin film / adhesive layer / chemical conversion treatment aluminum foil / primer layer / sealant film are laminated, the chemical conversion treatment is performed with a chromium compound, and the primer layer is an epoxy resin, a melamine resin, There is a disclosure of a laminated material for a secondary battery container comprising at least one selected from a urethane resin and a carboxy-modified polypropylene resin.

  Patent Document 3 discloses a laminated material formed of a laminate in which a biaxially stretched polyester film layer / biaxially stretched nylon film layer / metal foil layer / thermoadhesive resin layer are sequentially laminated, and the metal foil layer includes A film is formed by an aluminum foil and chromate treatment, and for example, a single layer of polyethylene, polypropylene, acid-modified polypropylene, etc., or two or more layers are appropriately laminated on the heat-adhesive resin layer. There is a disclosure of a laminate for a secondary battery container characterized by a composite layer.

  Patent Document 4 discloses a laminate in which a heat-resistant resin film layer / metal foil layer / thermoplastic resin film is laminated, and the impact strength of the heat-resistant resin film layer is 30000 J / m or more, and the metal foil layer is silane. Undercoating treatment such as coupling agent and titanium coupling agent, chemical conversion treatment such as chromate treatment, etc., thermoplastic resin film is unstretched film such as polypropylene, maleic acid modified polypropylene, ethylene acrylate copolymer or ionomer resin A laminated material for secondary battery containers characterized by the above has been proposed and put into practical use.

  Patent Document 5 discloses a multilayer film composed of a crystalline propylene polymer layer / acid-modified polyolefin resin layer / aluminum foil / polyamide layer / polyester resin layer as a multilayer film useful for housing food, daily necessities, secondary batteries and the like. A film, wherein the aluminum foil is treated with a non-chromium chemical conversion coating, and the crystallinity of the crystalline propylene polymer is 60% or more at the melting point of the acid-modified polyolefin resin. Multilayer films have been proposed.

  Patent Document 6 discloses a laminate composed of an aluminum foil having a barrier layer surface roughness of Ra 0.2 μm or more and Rmax 1.0 μm or more in a polymer battery packaging material comprising an outermost layer / barrier layer / innermost layer. .

JP 2003-288865 A JP 2003-288866 A JP 2002-56824 A JP 2005-22336 A JP 2009-61670 A JP 2001-35455 A

  However, when these laminated materials are used for the exterior materials for lithium ion batteries mounted on electric vehicles, hybrid vehicles, and electric motorcycles, the adhesion between the aluminum foil and the sealant film and the resistance to electrolytes are insufficient. Due to vibration during traveling on the road, the aluminum foil and the sealant film are liable to be peeled off, causing problems such as leakage of the electrolytic solution or scattering of the electrolytic solution.

  The object of the present invention is to further improve the adhesion between the aluminum foil and the sealant film and the electrolytic solution resistance, and the aluminum foil and the sealant film do not peel off due to vibration during road driving, and the internal electrolyte leaks and scatters. It is providing the aluminum foil laminated sheet for secondary battery exterior materials without fear of.

  As a result of intensive studies to solve the above problems, the inventors of the present invention laminated an aluminum foil (A), a modified polyolefin layer (B), and an unstretched polypropylene film (C) in this order, and at least the B side surface of A Is a surface-roughened secondary battery exterior having sponge-like voids continuous in the thickness direction from the surface, and the B-layer resin has entered the voids at a maximum penetration depth of 1 to 7 μm Invented an aluminum foil laminated sheet. Further, only the B side surface of A is roughened, and a spongy continuous void is formed from the surface in the thickness direction over a depth of 1 μm or more and 1/10 or less of the thickness of A. It has been found that the moldability is further improved by using an aluminum foil laminated sheet for a secondary battery exterior material characterized in that the resin penetrates into the voids and the maximum penetration depth is 1 μm or more.

  According to the present invention, the secondary battery exterior material using the aluminum foil laminated sheet of the present invention is excellent in adhesion and electrolyte resistance, and even when mounted on an electric vehicle, a hybrid vehicle, an electric motorcycle, etc. Due to vibration during running, the aluminum foil and the sealant film are not peeled off, and there is no possibility of leakage of the internal electrolyte solution or scattering of the electrolyte solution, and the reliability of the secondary battery can be greatly improved.

It is a scanning electron micrograph (5000 times magnification) of an example of the surface of the aluminum foil (A) of this invention. It is the scanning electron micrograph (magnification 5000 times) which observed the state of the interface of the aluminum foil (A) after lamination | stacking of an example of this invention, and a modified polyolefin layer (B).

  The present invention will be described in detail below.

  The aluminum foil laminated sheet for a secondary battery exterior material of the present invention is a laminated sheet in which an aluminum foil (A), a modified polyolefin layer (B), and an unstretched polypropylene film (C) are laminated. A has a function of preventing moisture from entering the battery from the outer surface. C has a function of overlapping and sealing (thermally bonding) the C sides of the laminated sheet for a secondary battery exterior material to form as an exterior material. A and C cannot be directly bonded, and B has an adhesive property with both A and C, and has a role of firmly bonding A and C.

  The surface of at least the B side of the aluminum foil (A) in the present invention is roughened and has spongy voids continuously in the thickness direction from the outermost surface. The sponge-like voids are preferably continuous from the surface up to a region having a maximum depth of 1 μm or more and 10 μm or less, and the roughening treatment sets the maximum depth of the sponge state to 1 μm or more. Thereby, adhesive force with B layer resin becomes enough. Even when the depth of the sponge state exceeds 10 μm, the adhesion is not improved, and the void portion roughened in a sponge shape cannot bear the strength of the aluminum foil. It is easy to break and the water vapor barrier performance is likely to deteriorate due to the generation of pinholes.

  In order to prevent the aluminum foil from being broken during molding and to maintain strength, the aluminum foil that has been roughened only on the B-side surface rather than the double-sided roughened aluminum foil is less likely to break when molded. Will improve. In this case, it is preferable that a spongy void that is continuous from the roughened B-side surface to a depth of 1 μm or more and 1/10 or less of the thickness of the aluminum foil in the thickness direction is formed. By setting the spongy void to 1/10 or less of the thickness of the aluminum foil, it is difficult to break when molded, and excellent moldability can be obtained. As a result, pinholes that cause deterioration of the water vapor barrier performance during molding are less likely to occur, and the water vapor barrier property of the aluminum foil is exhibited.

  The spongy voids are formed continuously from the surface and do not consist of pores independent of each other. The modified polyolefin layer resin of B enters into the spongy void from the interface laminated with A, that is, the surface of the aluminum foil in a molten or softened state, the adhesion between B and A is increased, and A and C are firmly bonded. It becomes like this.

As the aluminum foil (A) in the present invention, an aluminum foil in which spongy voids are formed by roughening treatment can be used. As a surface roughening treatment method for forming a spongy void of the aluminum foil (A), an etching treatment may be mentioned. A typical surface of the roughened surface is a sponge having 1 × 10 ⁸ to 1 × 10 ¹⁰ openings per 1 cm ² having a long side of an ellipse of 0.1 to 5 μm when observed from the surface. (See FIG. 1).

The aluminum foil (A) in the present invention is a high-purity aluminum foil containing 200 to 1000 ppm of Fe, 200 to 2000 ppm of Si, and 200 to 3000 ppm of Cu, and converted to alternating current with an electrolyte containing sulfuric acid, phosphoric acid, nitric acid, etc. in hydrochloric acid. Etching is performed by performing a treatment time of about 1 to 10 minutes at a current density of 0.1 to 1 A / cm ² . Moreover, the depth of a sponge state is controllable by controlling liquid tank temperature to 30-70 degreeC. Moreover, the aluminum foil which roughened only one side is producible by making only one side of aluminum foil contact electrolyte solution. As a specific example of A, a known cathode foil for an aluminum electrolytic capacitor can be used. Those having a capacitance of 99.9 μF / cm ² or more are more preferable because the surface area of the aluminum foil is large and the adhesion is high.

  By having the sponge-like voids, the modified polyolefin layer (B) resin enters the sponge-like voids, and B and A are firmly bonded, and as a result, A and C are firmly bonded. (See FIG. 2).

It is more preferable that the size of the opening on the surface of the aluminum foil is 0.1 μm to 5 μm because the B layer resin easily enters the void. When the number of openings on the surface of the aluminum foil is more than 1 × 10 ⁸ per 1 cm ² , the adhesion force between A and C is further improved, which is more preferable. When the number is less than 1 × 10 ^10, the mechanical strength of the portion where the voids A are formed is maintained, and the cohesive failure of the aluminum foil itself can be suppressed, and the peel strength can be increased.

  In the present invention, it is important that the B layer resin penetrates into the voids and the maximum penetration depth is 1 to 7 μm. The maximum penetration depth can be evaluated by observing a cross section of the interface between A and B after lamination in an evaluation method described later with a scanning electron microscope. The maximum penetration depth refers to the length of the modified polyolefin layer (B) resin penetrating from the surface opening of the aluminum foil in the depth direction. When the maximum penetration depth is less than 1 μm, the adhesion is insufficient. More preferably, the maximum penetration depth is 2 μm or more. When the maximum penetration depth exceeds 7 μm, the air in the spongy voids is partially pushed out to generate bubbles in the modified polyolefin layer. If bubbles are generated, the electrolyte solution Phenomenon in which the adhesive force decreases due to the influence is likely to occur. In particular, in the present invention, in order to obtain sufficient adhesion between B and A, the maximum penetration depth needs to be 1 μm or more.

  The thickness of the aluminum foil is preferably 10 to 100 μm. When the thickness is 10 μm or more, the aluminum foil is not easily torn by drawing when it is molded into a secondary battery exterior material, and when the thickness is 100 μm or less, the strength of the waist as a laminated sheet is suitable and easy to handle, and the formability is also preferable. More preferably, the thickness is 20 to 50 μm.

  The value obtained by subtracting the maximum depth of the formation area of the sponge-like voids from the thickness of the aluminum foil is 10 μm or more, so that the strength of the aluminum foil is maintained, and there is no risk of tearing or pinholes during molding. To preferred.

Further, the water vapor permeability of A (JIS K7129: 2008) is 0.05 g / m ² · 24 h (40 ° C. × 90% RH) or less, so that moisture penetrates into the secondary battery and It is more preferable from the viewpoint of preventing the performance from being deteriorated.

  As the unstretched polypropylene film (C), a known polypropylene film for sealant can be used.

  A non-stretched film is preferable because the heat seal temperature is lower than that of a stretched film, and the secondary battery container is easily formed by heat sealing. This is because in the case of non-stretching, the entanglement of polypropylene molecules easily proceeds during sealing.

  As for the film thickness of C, when the thickness is 25 μm or more, the sealing strength for molding the outer packaging material of the secondary battery is improved, the seal is difficult to peel off, the liquid is less likely to leak, and the thickness is When the thickness is 100 μm or less, an unstretched polypropylene film having the thickness is easily available on the market, and thus the thickness is more preferably 25 to 100 μm.

  In the present invention, the modified polyolefin layer (B) is provided between the aluminum foil (A) and the unstretched polypropylene film (C).

  Here, the modified polyolefin is a polyolefin having a functional group component. As the modified polyolefin, an amino group, a carboxyl group, a hydroxyl group, a maleic anhydride group, a silane group, an acrylic acid group, an acrylic acid is added to a polyolefin such as polyethylene or polypropylene. It is obtained by polymerizing olefins such as ethylene and propylene as main monomers and comonomers such as acrylic acid, vinyl acetate, glycidyl methacrylate, methyl acrylate, etc., in which functional groups having bonding properties with aluminum such as ester groups are introduced. Known ones such as olefin copolymers are used. In particular, graft-modified polyethylene having a functional group graft-bonded and having a melting point of 110 to 130 ° C. and a graft-modified polypropylene having a melting point of 140 to 170 ° C. are preferable from the viewpoint of adhesion to an aluminum foil. These are graft copolymers obtained by graft copolymerizing unsaturated carboxylic acid or its anhydride with all or part of polyethylene or polypropylene constituting the main skeleton.

  The modified polyolefin is more preferably a graft-modified polypropylene in terms of adhesion to the unstretched polypropylene of the C layer.

  The polypropylene constituting the main skeleton of the graft-modified polypropylene is a homopolymer of propylene, or a block copolymer or a random copolymer composed of propylene and another monomer. Examples of other monomers include ethylene, 1-butene, isobutene, 1-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 1-hexene, 3-methyl-1-pentene, 2-methyl-1-pentene, 1-heptene and the like can be mentioned, and these may include one or a combination of two or more in polypropylene. The content of other monomers in the polypropylene is usually 10% by weight or less. Among these, from the viewpoint of cost, a propylene homopolymer, an ethylene / propylene block copolymer, and an ethylene / propylene random copolymer are preferable. Examples of the unsaturated carboxylic acid or its anhydride (hereinafter referred to as “graft monomer”) that is graft-copolymerized on polypropylene to form a modified polypropylene include unsaturated monocarboxylic acids such as acrylic acid and methacrylic acid, and maleic acid. Acids, fumaric acid, itaconic acid, citraconic acid, allyl succinic acid, mesaconic acid, glutaconic acid, nadic acid, methyl nadic acid, tetrahydrophthalic acid, methyltetrahydrophthalic acid and other unsaturated dicarboxylic acids, maleic anhydride, itaconic anhydride, Examples thereof include unsaturated dicarboxylic anhydrides such as citraconic anhydride, allyl succinic anhydride, glutaconic anhydride, nadic anhydride, methyl nadic anhydride, tetrahydrophthalic anhydride, and methyl tetrahydrophthalic anhydride. The graft-modified polypropylene may contain one or a combination of two or more of these graft monomers. Among these, maleic acid, maleic anhydride, nadic acid, and nadic anhydride are preferable from the viewpoints of cost and physical properties. The content of the graft monomer in the modified polypropylene is 0.1 to 10% by weight in that an adhesive composition excellent in adhesiveness with an aluminum foil and adhesiveness with an unstretched polypropylene film is obtained. Yes, preferably 0.5 to 5% by weight.

  The modified polyolefin is easily bonded to both the aluminum foil (A) and the unstretched polypropylene film (C), and the modified polyolefin layer reduces the ease of separation of A and C due to vibration during running of an automobile or the like.

  When the thickness of the modified polyolefin layer is 10 μm or more, it becomes difficult to separate A and C. When the thickness is 50 μm or less, the modified polyolefin layer is not easily broken by vibration, so the thickness of the modified polyolefin layer is 10 μm. To 50 μm is more preferable.

  The modified polyolefin layer can be provided between A and C by a lamination method by extrusion coating using a modified polyolefin resin. Further, a modified polyolefin layer can be formed on C in advance.

  Although the manufacturing method of the lamination sheet of this invention is not specifically limited, It can form with the following method.

  An aluminum foil (A) and an unstretched polypropylene film (C) are laminated as a sandwich layer between A and C by using the layer (B) obtained by melt-extrusion of the above-mentioned modified polyolefin, and an A / B / C laminated film is obtained. Can be created. Alternatively, an A / B / C laminated film can be obtained by previously providing a film (B) made of the above modified polyolefin on an unstretched polypropylene film (C) and laminating A and a B / C laminate. it can. In addition, after this, it is preferable to apply pressure bonding under conditions of 0.1 to 1.0 MPa in a temperature range from the melting point of B to 20 ° C. higher than the melting point of B.

  It is preferable to apply pressure bonding at a temperature equal to or higher than the melting point of B because the resin of B enters the spongy voids of the aluminum foil and the adhesion is improved. When pressure-bonded at a temperature of 20 ° C. or higher than the melting point of B, the modified polyolefin resin has a reduced viscosity and can penetrate deeper into the sponge-like voids of the aluminum foil. When air bubbles are easily generated in the extruded B resin, and the air bubbles are generated, a phenomenon that the adhesive force is lowered due to the influence of the electrolytic solution is likely to occur at this point, so that the temperature is 20 ° C. higher than the melting point of B. It is preferable to heat-press with.

  Similarly, pressure bonding at 0.1 MPa or more is preferable because the B resin enters the spongy voids of the aluminum foil and the adhesion is improved. When pressure bonding is performed at 1.0 MPa or more, bubbles are easily generated due to a reaction in which a large amount of the B layer resin is partially pushed into the spongy void, and it is preferable to perform pressure bonding at 1.0 MPa or less.

  The secondary battery exterior material is made of a laminated material in which, for example, a nylon film and a polyethylene terephthalate film are laminated on an aluminum foil opposite to the surface on which the unstretched polypropylene film of the aluminum foil laminated sheet of the present invention is bonded. Created. Moreover, a nylon film and a polyethylene terephthalate film can be laminated on the aluminum foil laminated sheet of the present invention alone. Two sheets can be cut out from these laminates, stacked so that the unstretched polypropylene film (C) is on the inside, and the three sides can be heat-sealed together to form a bag by heat-sealing. . Also, a piece of laminated material is cut out, one end is folded so that the unstretched polypropylene film (C) is on the inside, and two sides of the side are heat-sealed in the same manner as described above to heat-seal the unstretched polypropylene films together. Can be created.

  In addition, the secondary battery exterior material is obtained by cutting out two laminated material pieces from the laminated material, drawing one laminated material with a mold so that the polyethylene terephthalate film is outside, and generating power for the secondary battery. A molding material provided with a drawing part for containing elements and another laminated material are laminated on the unstretched polypropylene film (C) side and fused by heat sealing to create an exterior material. it can.

  EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited only to these Examples. Each characteristic value was measured by the following method.

(1) Film, aluminum foil thickness
Using an electronic micrometer (K-312A type manufactured by Anritsu Corporation), the film thickness and the thickness of the aluminum foil were measured at a needle pressure of 30 g.

(2) Thickness of modified polyolefin layer (B) between A and C A / B / C laminated sheet small piece (2mm x 2mm) epoxy resin (trade name "Epomount" manufactured by Refine Tech Co., Ltd.) It was embedded in, sliced to a thickness of 50 nm together with the embedding resin using a microtome, and obtained by observation with a transmission optical microscope (“Eclipse E100” manufactured by Nikon Instruments Co., Ltd.) at a magnification of 500 times.

(3) Adhesiveness The laminated sheet is peeled off about 5 cm between the B layer and the C layer, and is set on the upper and lower chucks of a tensile tester (Tensilon). The adhesion strength (N / 15 mm) was determined and the adhesion was evaluated according to the following criteria (based on JIS-K6854-3: 1999). The measurement was performed with 5 samples, and the average value was evaluated.
A: 15 N / 15 mm or more and all of the evaluation samples are 15 N / 15 mm or more A to B: The average value is 15 N / 15 mm or more, but one or more of the evaluation samples is less than 15 N / 15 mm B : 10 N / 15 mm or more and less than 15 N / 15 mm C: Less than 10 N / 15 mm.

(4) Electrolytic solution resistance As an electrolytic solution resistance confirmation evaluation of the laminated sheet, a laminated sheet cut out to a width of 15 mm and a sample length of 15 cm is divided into ethylene carbonate / dimethyl carbonate / diethyl carbonate = 1/1/1 (weight ratio). Immerse it in lithium fluoride phosphate (concentration 1 mol / L) and store it in an atmosphere at 85 ° C. for 1 week, then peel it off about 5 cm, use a tensile tester (Tensilon), and crosshead speed 50 mm / The adhesion strength (N / 15 mm) was determined by T-type peeling, and the electrolytic solution resistance was evaluated according to the following criteria. (Conforms to JIS-K6854-2)
A: 15 N / 15 mm or more and all of the evaluation samples are 15 N / 15 mm or more A to B: The average value is 15 N / 15 mm or more, but one or more of the evaluation samples is less than 15 N / 15 mm B : 10 N / 15 mm or more and less than 15 N / 15 mm C: less than 10 N / 15 mm (5) Appearance of laminated sheet A / B / C laminated sheet is cut into a size of 10 cm × 10 cm and visually observed from the unstretched polypropylene sheet side. Observation was made and the state of bubble generation was evaluated according to the following criteria.
A: Number of bubbles 0 to 1 / sheet B: Number of bubbles 2 to 20 / sheet C: Number of bubbles 21 or more / sheet (6) Sponge state observation method of aluminum foil Pt-coated on the surface of aluminum foil The surface of the aluminum foil and the cross-section of the aluminum foil were obtained by ion milling, coating the processed surface with Pt, and accelerating voltage of 2.0 kV using Hitachi field emission scanning electron microscope (FE-SEM) S-4800. Observations were made. The formation state of spongy voids and the formation range from the surface were evaluated at a magnification of 5000 times.

(7) Depth of penetration of B layer resin By the same method as in (6) above, the cross section in the thickness direction near the interface of the A layer / B layer of the laminated sheet was observed with FE-SEM, The maximum penetration depth of the B layer resin when observed in the width direction of 25 μm was measured as indicated by a solid line double arrow in FIG. That is, among the interfaces between the A layer and the B layer in the FE-SEM cross-sectional photograph (FIG. 2), the position of the interface existing on the most B layer side (dotted line portion in FIG. 2) was set to 0 μm, and the most penetrated to the A layer side. The depth (3 in FIG. 2) up to the position (the chain line portion in FIG. 2) was defined as the maximum penetration depth (μm). Note that the position where the B layer resin entered the A layer side compares the contrast of the B layer resin in the FE-SEM photograph with the contrast in the gap of the A layer, and identifies the infiltrated portion and the non-infiltrated portion of the B layer resin. Judged by. Such measurement was performed for three different measurement visual fields in the width direction, and the maximum value was calculated.

(8) Melting point of modified polyolefin The melting point of the modified polyolefin is determined by melting point measurement according to JIS-K7121: 1987 using a differential scanning calorimeter (DSC).

(9) Formability: Adhesive Rock Bond JRU-80 / H-5 manufactured by Rock Paint Co., Ltd. is applied to a 25 μm nylon film “Emblem” (registered trademark) ON with a solid content of 3.5 μm. And after heat drying, it bonded together with the aluminum foil side of the aluminum foil laminated sheet by the dry lamination method. Drawing was performed so that the nylon film was on the convex side. The size of molding is 30 mm x 50 mm (mold recess shape: corner R, bottom R and flange R are all 3 mm), and the molding depth is increased from 4 mm to 1 mm at a time. Evaluation was performed based on the maximum drawing depth at which the laminated material was not damaged.
A: No tearing occurred at a drawing depth of 6 mm.
A to B: Spot-like pinholes were observed in the transmitted light at a diaphragm depth of 6 mm.
B: Breaking occurred at a drawing depth of 6 mm. C: Breakage occurred at a drawing depth of 5 mm or less.

(10) Container evaluation Rocklock JRU-80 / H-5 adhesive is applied to a 25 μm unit nylon film “Emblem” (registered trademark) ON with a solid content of 3.5 μm. And after heat drying, it bonded together with the aluminum foil side of the aluminum foil laminated sheet by the dry lamination method. Drawing was performed so that the nylon film was on the convex side. The molding was carried out with a size of 30 mm × 50 mm (mold recess shape: corner R, bottom R and flange R are all 3 mm), and the drawing depth at the time of molding was 4 mm. Two laminates after molding were stacked so that the polypropylene film sides were inside the container, and three-way sealing was performed with an impulse sealer at a heat sealing temperature of 210 ° C. Thereafter, 5 ml of lithium hexafluorophosphate (concentration: 1 mol / L) was injected into ethylene carbonate / dimethyl carbonate / diethyl carbonate = 1/1/1 (weight ratio), and the remaining one seal was carried out. Was made. The container was stored at 60 ° C. for 120 hours, and the appearance was observed after storage.
A: There was no problem of liquid leakage.
AB: There was no liquid leakage, but discoloration was observed in the liquid after storage.
B: Although there was no liquid leakage, dotted pinholes were confirmed in the transmitted light.
C: There were problems such as liquid leakage.

[Example 1]
Aluminum foil (A) (cathode foil 1085 for aluminum electrolytic capacitor manufactured by Showa Denko KK) having a roughened surface on both sides with a thickness of 30 μm and unstretched polypropylene film (C) with a thickness of 70 μm (Toyobo Co., Ltd.) A modified polyolefin (B) (Mitsubishi Chemical Co., Ltd. graft modified polypropylene “Modic” P553A, melting point 143 ° C.) having a main component of polypropylene extruded from a “pyrene” film—CTP P1146) with a thickness of 30 μm between A and C After laminating and laminating, the aluminum foil laminated sheet of the present invention was prepared by pressure bonding under conditions of 145 ° C. and 0.2 MPa. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 2]
Example 1 except that graft modified polypropylene “Modic” P502 (melting point: 168 ° C.) manufactured by Mitsubishi Chemical Co., Ltd. was used for the B layer as the modified polyolefin (B) in Example 1, and pressure-bonded under conditions of 170 ° C. In the same manner, an aluminum foil laminated sheet of the present invention was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 3]
In Example 1, as the modified polyolefin (B), graft modified low-density polyethylene “Modic” L502 (melting point: 110 ° C.) manufactured by Mitsubishi Chemical Corporation was used as the B layer, and this was carried out except that it was pressure-bonded at 120 ° C. In the same manner as in Example 1, an aluminum foil laminated sheet of the present invention was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 4]
Example 1 except that graft modified linear low density polyethylene “Modic” M502 (melting point: 124 ° C.) manufactured by Mitsubishi Chemical Corporation was extruded as the modified polyolefin (B) in Example 1 and pressure-bonded under the condition of 125 ° C. In the same manner as in Example 1, an aluminum foil laminated sheet of the present invention was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 5]
In Example 1, as modified polyolefin (B), graft modified high-density polyethylene “Modic” H503 (melting point: 128 ° C.) manufactured by Mitsubishi Chemical Corporation was extruded and pressure-bonded under conditions of 130 ° C. Similarly, the aluminum foil laminated sheet of the present invention was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 6]
In Example 1, as the modified polyolefin (B), an ethylene / methyl methacrylate copolymer “Aclift” WD301 (melting point: 100 ° C.) manufactured by Sumitomo Chemical Co., Ltd. was extruded, and the pressure bonding temperature was changed to 110 ° C. In the same manner as in Example 1, an aluminum foil laminated sheet of the present invention was prepared. The adhesion was good, but the electrolytic solution resistance was slightly inferior. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 7]
An aluminum foil laminated sheet of the present invention was prepared in the same manner as in Example 1 except that the pressure bonding temperature in Example 1 was 165 ° C. There was no problem with the adhesion, but the appearance of bubbles was observed, and this was the cause, and the electrolyte resistance was slightly inferior. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 8]
An aluminum foil laminated sheet of the present invention was prepared in the same manner as in Example 1 except that the applied pressure was set to 0.07 MPa in Example 1. The characteristics are shown in Table 1. Since the pressurizing pressure was low, the penetration depth was as small as 1.2 μm, and the adhesion and electrolyte resistance were slightly inferior. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 9]
An aluminum foil laminated sheet of the present invention was prepared in the same manner as in Example 1 except that the pressure was 1.4 MPa in Example 1. The characteristics are shown in Table 1. Bubbles were observed as in Example 7, and the electrolyte resistance was slightly inferior. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 10]
An aluminum foil having a thickness of 40 μm (BESPA8021 manufactured by Sumi Light Aluminum Foil Co., Ltd.) is brought into contact with an electrolyte containing hydrochloric acid only on one side and treated by a known etching method using an AC power source, and only one side surface is in the thickness direction from the surface. An aluminum foil roughened in a spongy manner in the range of 4 μm was prepared. The present invention was carried out in the same manner as in Example 1 except that the present aluminum foil was used as the aluminum foil (A) in Example 1 and A / B / C was laminated with the roughened surface of A facing the B side. An aluminum foil laminated sheet was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 11]
An aluminum foil having a thickness of 40 μm (BESPA8021 manufactured by Sumi Light Aluminum Foil Co., Ltd.) is brought into contact with an electrolyte containing hydrochloric acid only on one side and treated by a known etching method using an AC power source, and only one side surface is in the thickness direction from the surface. An aluminum foil roughened in a spongy form in a range of 7 μm was prepared. The present invention was carried out in the same manner as in Example 1 except that the present aluminum foil was used as the aluminum foil (A) in Example 1 and A / B / C was laminated with the roughened surface of A facing the B side. An aluminum foil laminated sheet was prepared. Moreover, the container was produced. The characteristics are shown in Table 1.

[Example 12]
A 40 μm thick aluminum foil (BESPA8021 manufactured by Sumi Light Aluminum Foil Co., Ltd.) is treated by a known etching method using an AC power source in an electrolyte containing hydrochloric acid, and both surfaces are in the range of 4 μm in the thickness direction from the surface. An aluminum foil roughened in a sponge shape was prepared. An aluminum foil laminated sheet of the present invention was prepared in the same manner as in Example 1 except that the present aluminum foil was used as the aluminum foil (A) in Example 1. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 1]
In Example 1, an aluminum foil laminated sheet was prepared in the same manner as in Example 1 except that the pressure bonding temperature was set to 135 ° C. The penetration depth was 0.5 μm, and the adhesion and resistance to electrolytic solution were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 2]
In Example 2, an aluminum foil laminated sheet was prepared in the same manner as in Example 2 except that the applied pressure was 0.05 MPa. The penetration depth was 0.8 μm, and the adhesion and electrolyte resistance were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 3]
In Example 1, an aluminum foil laminated sheet was prepared in the same manner as in Example 1 except that the pressure bonding temperature was 175 ° C. The penetration depth was 7.5 μm and the adhesion was good, but many bubbles were generated and the electrolyte resistance was insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 4]
In Example 1, an aluminum foil laminated sheet was prepared in the same manner as in Example 1 except that the applied pressure was 2 MPa. The penetration depth was 8.1 μm and the adhesion was good, but many bubbles were generated and the resistance to electrolytic solution was insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 5]
In Example 1, an aluminum foil was used in the same manner as in Example 1 except that a treated aluminum foil ("Super-Ecoat" manufactured by Mitsubishi Aluminum Co., Ltd.) having a film formed by electrolytic treatment was used as the aluminum foil (A). A laminated sheet was created. The characteristics are shown in Table 1. There was no penetration of the B layer resin, and both the adhesion and the resistance to electrolytic solution were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 6]
An aluminum foil laminated sheet was prepared in the same manner as in Example 1 except that an aluminum foil having a thickness of 40 μm (BESPA8021 manufactured by Sumikara Aluminum Foil Co., Ltd.) was used as the aluminum foil (A). There was no penetration of the B layer resin, and both the adhesion and the resistance to electrolytic solution were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 7]
Instead of using modified polyolefin in Example 1, instead of extruding high pressure method low density polyethylene “UBE polyethylene” L719 (melting point: 108 ° C.) manufactured by Ube Industries, Ltd., and applying the pressure bonding temperature to 120 ° C. In the same manner as in Example 1, an aluminum foil laminated sheet was prepared. The penetration depth was 1.6 μm, but the adhesion and resistance to electrolytic solution were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

[Comparative Example 8]
In Example 1, the B-layer resin was not extruded, and the unstretched polypropylene film (C) was directly laminated on the aluminum foil, and pressure-bonded at 165 ° C. Both adhesion and resistance to electrolytic solution were insufficient. Moreover, the container was produced. The characteristics are shown in Table 1.

  The laminated material of the present invention has good workability, and the exterior body made from the aluminum foil laminated sheet of the present invention is excellent in adhesion, electrolyte resistance, vibration resistance, and impact resistance. It is suitably used as a laminated sheet for a secondary battery exterior body mounted on a motorcycle.

1. Modified polyolefin layer (B)
2. Aluminum foil (A)
3. Penetration depth

Claims (4)

An aluminum foil (A), a modified polyolefin layer (B), and an unstretched polypropylene film (C) are laminated in this order, and at least the B side surface of A is roughened, and the thickness from the roughened surface is increased. An aluminum foil laminate for a secondary battery exterior material, characterized in that a spongy void continuous in the direction is formed, the B layer resin penetrates into the void, and the maximum penetration depth is 1 to 7 μm Sheet. An aluminum foil (A), a modified polyolefin layer (B), and an unstretched polypropylene film (C) are laminated in this order, and only the B side surface of A is roughened, and the thickness direction from the roughened surface A continuous spongy void is formed over a depth of 1 μm or more and 1/10 or less of the thickness of A, and the B layer resin penetrates into the void, and the maximum penetration depth is 1 μm or more. An aluminum foil laminated sheet for a secondary battery exterior material. The aluminum foil laminated sheet for a secondary battery exterior material according to claim 1 or 2, wherein the modified polyolefin layer (B) is a graft-modified polypropylene having a melting point of 140 to 170 ° C. Lamination obtained by laminating a nylon film and / or a polyester film on a surface of the aluminum foil (A) of the aluminum foil laminated sheet for secondary battery exterior materials according to any one of claims 1 to 3 on which the B layer is not laminated. A secondary battery exterior material on which a sheet is formed.