JP3922826B2 - Battery container lid, battery container and package using the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a battery container lid and a battery container having excellent corrosion resistance and a package using the same, and more particularly to a lid, a container and a package suitable for an organic electrolyte battery.
[0002]
[Prior art]
Conventionally, laminates made of aluminum foil (including aluminum thin plates) and resin films are mainly used for packaging and packing foodstuffs, beverages, chemicals, daily necessities, and various parts. Corrosion resistance, moldability, and molding There was no development that emphasized later strength. In particular, in an organic electrolyte battery, the permeability of the electrolyte solution to a resin film or an adhesive is strong, and a laminate having a conventional structure does not have sufficient corrosion resistance and cannot be used. That is, during long-term use, delamination (discoloration), discoloration, corrosion, and the like occur, resulting in inconveniences such as electrolyte leakage and container deformation.
[0003]
In recent years, small and lightweight organic electrolyte batteries for use in small and thin portable personal computers, electronic notebooks, mobile phones and the like are under development, and lightweight containers having sufficient moldability and strength suitable for them are being developed. It has not been obtained yet.
[0004]
[Problems of the Invention]
Accordingly, an object of the present invention is to provide a battery container lid, a battery container, and a package that are excellent in corrosion resistance, easy to mold, and excellent in shape retention and shape stability.
[0005]
[Means for solving problems]
In order to solve the above problems, in the present invention, (a) an exterior resin film having a thickness of 15 μm or more, (b) an aluminum layer having a thickness of 50 to 300 μm, (c) a polyamide-based resin and EVOH (ethylene-vinyl alcohol) The battery container lid was formed of a laminate in which at least a two-layer corrosion resistant layer made of a polymer) and (d) a heat seal layer were sequentially laminated.
[0006]
Further, (a) an exterior resin film having a thickness of 15 μm or more, (b) an aluminum layer having a thickness of 50 to 300 μm, (c) a corrosion-resistant layer having at least a two-layer structure comprising a polyamide-based resin and EVOH (ethylene-vinyl alcohol copolymer). (D) A laminate in which heat seal layers are sequentially laminated is formed to form a battery container.
[0007]
The corrosion-resistant layer can have a three-layer structure of polyamide-based resin / EVOH / polyamide-based resin, and the corrosion-resistant layer can be made of polyamide-based resin / EVOH / polyamide-based resin / polyamide-based resin / EVOH / polyamide-based resin. It can be a layered structure. Moreover, the said exterior resin film can be formed with a polyamide-type resin.
[0008]
A package is obtained by ring-sealing the lid as described above to the container.
[0009]
[Embodiment]
Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a package and a heat seal hot plate. As illustrated, the package includes a container 10 and a lid 20. The container 10 has a bottom wall 11 and a peripheral wall 12 rising from the peripheral edge thereof, and a flange 13 is provided on the outer periphery of the upper end of the peripheral wall 12. The lid 20 is made of a flat sheet or plate that has substantially the same shape as the outer edge of the flange 13 of the container 10. The lid 20 is heat sealed to the flange 13 of the container 10 with a heat seal hot plate 30 to complete the package.
[0010]
The laminated structure of the laminated body which forms the said container 10 and the lid | cover 20 is shown in FIG. As shown in the figure, the laminate 1 is formed on the outer surface of the aluminum layer 2 as a base material, the exterior resin film 3 laminated on one surface thereof, the corrosion-resistant layer 4 laminated on the other surface of the aluminum layer 2. The heat seal layer 5 is formed.
[0011]
The exterior resin film 3 may be a resin film having a thickness of 15 μm or more, preferably 15 to 50 μm, specifically, one or more of polyamide, high density polyethylene, polypropylene, PET (polyethylene terephthalate) and the like. Among these, the use of a polyamide-based resin (nylon) is particularly preferable. If the thickness is less than 15 μm, cracks or the like may occur during molding, and delamination may occur in the bent portion after molding, and use should be avoided. On the other hand, the upper limit is not particularly defined, but is preferably about 50 μm. Even if it exceeds 50 μm, it only leads to an increase in cost, and further performance improvement cannot be expected.
[0012]
The aluminum layer 2 used as the substrate is preferably an aluminum foil or a thin aluminum plate having a thickness of 50 to 300 μm, preferably about 70 to 200 μm. If the thickness is less than 50 μm, sufficient strength after molding cannot be obtained, and deformation or cracking may occur after molding, which may cause liquid leakage and short circuit of the internal current collector, etc. Should. On the other hand, the upper limit is not specified from the viewpoint of performance, but considering cost, moldability, and weight as a product, it should be 300 μm or less, and if it exceeds this, these required characteristics are not satisfied. The purity of the aluminum layer is not particularly limited, and a known material such as industrial pure aluminum or an alloy such as (JIS) 3003, 3004, 5052, 8079 can be adopted, and a clad material in which two or more kinds are laminated is used. There is no problem.
[0013]
As shown in FIG. 3, the corrosion-resistant layer 4 positioned between the aluminum layer 2 and the heat seal layer 5 has at least a two-layer structure composed of PA41 (polyamide resin) and EVOH42 (ethylene-vinyl alcohol copolymer). . The corrosion-resistant layer 4 can employ any two or more structures such as a three-layer structure and a six-layer structure in addition to a two-layer structure. Industrially, the cost and lamination process are taken into consideration in terms of performance, and about 6 layers are optimal. Specifically, in the case of a three-layer structure in which the polyamide resin is arranged on the outside, PA41a / EVOH42 / PA41b as shown in FIG. 4, and in the case of a six-layer structure, PA41a / EVOH42a / PA41b as shown in FIG. The configuration may be / PA41c / EVOH42b / PA41d. The thickness of each layer is preferably about 3 to 20 μm for PA and about 2 to 25 μm for EVOH, and the total thickness of the corrosion-resistant layer 4 after multilayer lamination is preferably about 12 to 60 μm. When PA is less than 3 μm, EVOH is less than 2 μm, and the total thickness is less than 12 μm, corrosion resistance, barrier properties, etc. are not sufficient, which may cause liquid leakage or breakage. Even if PA is 20 μm, EVOH is 25 μm, and the total thickness exceeds 60 μm, only a cost increase and a decrease in shape retention are caused, and no further improvement in performance is recognized. Although not particularly specified, PA / EVOH adhesion is preferably co-extruded, and PA / PA adhesion is preferably performed by using a two-component reactive polyurethane resin adhesive as an adhesive and by dry lamination.
[0014]
For the heat seal layer 5, a resin or a film excellent in sealing property, hot tack property, squeezing property, and oil resistance can be employed. For example, EAA (ethylene-acrylic acid copolymer), EMAA (ethylene-methacrylic acid) Copolymer), EEA (ethylene-ethyl acrylate copolymer), EMAC (ethylene-methyl acrylate copolymer), ionomer inflation film, bondine (ethylene / ethyl acrylate / maleic anhydride terpolymer: Sumitomo Chemical Industries) Co., Ltd.), Mersen M (polyolefin-based adhesive resin: manufactured by Tosoh Corporation), etc., among which the use of an ionomer inflation film (for example, HM52: manufactured by Tamapoly Co., Ltd.) is particularly preferable. The thickness of the heat seal layer 5 is preferably 20 to 70 μm. If the thickness is less than 20 μm, sufficient adhesive strength cannot be obtained, and if it exceeds 70 μm, the cost may increase and the barrier property of the heat seal layer itself may decrease. There is no need to make it unnecessarily thick.
[0015]
The method for laminating and adhering between the layers is not particularly limited, and a known method such as dry lamination using a two-component curable urethane adhesive, coextrusion, extrusion coating or the like can be employed. In addition, an anchor coat layer, a print layer, a decoration layer, an overcoat layer, or the like may be applied to any layer as necessary.
[0016]
In order to form the container 10, a known press machine such as a hydraulic press, a mechanical (crank) press, a hydraulic press, a manual press, or the like can be used. It is preferable to mold. The shape and size of the molded container are appropriately designed according to the application and purpose.
[0017]
The molded container 10 contains the contents, for example, an electrolyte, a current collector, an active material, a lead wire, etc., and the lid 20 made of the laminate 1 is heat-sealed, preferably ring-sealed, as shown in FIG. Such a package is obtained. Here, the ring seal refers to heat sealing using a heat plate 30 having a convex ridge 31 or a concave groove with respect to a heat seal using a normal flat plate (heat plate). Usually, the width of the ring portion 21 is preferably about 0.3 to 5 mm, and the depth or height of the ring portion 21 is preferably about 0.1 to 2 mm. Due to the effect of the ring seal, the adhesive strength of the seal portion is improved, oxygen and moisture entering the inside from the heat seal portion of the package are suppressed, and the life of the contents can be extended.
[0018]
[Examples and Comparative Examples]
A laminate (about 500 × 500 mm) having the configuration shown in FIGS. 6 and 7 was prepared. D in the table indicates dry lamination, and the numbers surrounded by circles are the materials indicated by the corresponding numbers in FIG. A specimen for an 80 × 180 mm molded container and a lid of 62 × 162 mm were cut out from these laminates. The specimen for the molded container was press-molded into a shape shown in FIG. 1 by a cold press. After a solvent or an organic electrolyte described later is almost completely injected into the molded container, a ring seal (a hot plate 30 having protrusions 31 shown in FIG. 1) is formed between the container flange portion and the lid with a width of 2 mm and a depth of 0.5 mm. And sealed at a hot plate temperature of 180 ° C. for 3 seconds. The solvent used was a mixture of diethyl carbonate and ethylene carbonate at a volume ratio of 1: 1. As the electrolytic solution, one obtained by dissolving 1 mol / liter of lithium hexafluorophosphate (LiPF6) in the above solvent was used. The PH was about 3. The following tests were performed for each of the obtained packages. The results are shown in FIG.
[0019]
[Immersion test] The sealed package was left in a thermostatic chamber at 60 ° C for 7 days, then taken out from the thermostatic chamber, and the results of observation of the appearance of the package and the inner surface after opening, etc. are shown in the same table.
Evaluation ○: No change (no corrosion / discoloration of aluminum, delamination, etc.).
X: Corrosion / discoloration of aluminum, delamination (exfoliation), generation of bubbles, etc. occur.
[0020]
[Moldability] The properties of the bent portion of the laminate during press molding were visually observed.
Evaluation ○: No abnormality.
X: Delamination, wrinkles, cracks, etc. occurred in part.
[0021]
[Ring sealability] The state of adhesion after ring sealing was confirmed by hand.
Evaluation ○: Adhered well.
X: It is not completely welded in a groove shape and is easily peeled off by hand.
[0022]
【effect】
The lid and container of the present invention and the package using them use a laminate having a specific structure not seen in the past, and are excellent in moisture resistance, airtightness and organic electrolyte resistance, and stable for a long time. It can be used as packaging material. Furthermore, since it can be formed into an arbitrary shape, it can be suitably used for various battery cases. It is particularly effective for organic electrolyte batteries, and has excellent corrosion resistance, and the effect of the ring seal can prevent strong adhesion and intrusion of moisture, oxygen, etc. from the end face of the heat seal layer of the flange, thus extending the battery performance. Can contribute.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a package and a heat-sealing hot plate of the present invention. FIG. 2 is a cross-sectional view showing a laminate forming the package. FIG. 3 is a cross-sectional view showing a corrosion-resistant layer of the laminate. FIG. 5 is a cross-sectional view showing another example of the corrosion-resistant layer. FIG. 6 is a cross-sectional view showing the structure of the laminate of the example and the comparative example. FIG. Chart showing the structure of the body [FIG. 8] Chart showing the material used for the laminate [FIG. 9] Chart showing the test results of the packaging bodies of the examples and comparative examples [Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Laminated body 2 Aluminum layer 3 Exterior resin film 4 Corrosion-resistant layer 5 Heat seal layer 10 Container main body 11 Bottom wall 12 Perimeter wall 13 Flange 20 Lid 21 Ring part 30 Hot plate 31 Projection 41, 41a, 41b, 41c, 41d Polyamide-type resin 42, 42a, 42b ethylene-vinyl alcohol copolymer

Claims (9)

  (A) an exterior resin film having a thickness of 15 μm or more, (b) an aluminum layer having a thickness of 50 to 300 μm, (c) a corrosion-resistant layer having at least a two-layer structure composed of a polyamide-based resin and EVOH (ethylene-vinyl alcohol copolymer), d) A battery container lid comprising a laminate in which heat seal layers are sequentially laminated.   (A) an exterior resin film having a thickness of 15 μm or more, (b) an aluminum layer having a thickness of 50 to 300 μm, (c) a corrosion-resistant layer having at least a two-layer structure composed of a polyamide-based resin and EVOH (ethylene-vinyl alcohol copolymer), d) A battery container in which a laminate in which heat seal layers are sequentially laminated is formed. IkeHiroshi dexterity Lid collector of claim 1, wherein the corrosion resistant layer is a three-layer structure of the polyamide resin / EVOH / polyamide-based resin.   The battery container according to claim 2, wherein the corrosion-resistant layer has a three-layer structure of polyamide resin / EVOH / polyamide resin.   The lid for a battery container according to claim 1, wherein the corrosion-resistant layer has a six-layer structure of polyamide resin / EVOH / polyamide resin / polyamide resin / EVOH / polyamide resin.   The battery container according to claim 2, wherein the corrosion-resistant layer has a six-layer structure of polyamide resin / EVOH / polyamide resin / polyamide resin / EVOH / polyamide resin.   The battery container lid according to claim 1, wherein the exterior resin film is made of a polyamide-based resin.   The battery container according to claim 2, wherein the exterior resin film is made of a polyamide-based resin.   A package in which the battery container according to any one of claims 2, 4, 6, and 8 and the battery container lid according to any one of claims 1, 3, 5, or 7 are ring-sealed.

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