JP2005183051A - Battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop a battery of one packed by an aluminum-laminated film with improved shock resistant property without making the size substantially larger. <P>SOLUTION: The battery device 100 is composed of a chassis 1, a chassis 2, and a packed battery 3, and the packed battery 3 is composed of a lithium secondary battery 4 and a battery packaged body 5. The lithium secondary battery 4 has a structure of four sheets of a separator 41, anode sheet 42, separator 43 and cathode sheet 44 wound around. The packaged body 51 is provided with a base material layer 511, adhesive layer 512, metal reinforcing layer 513, aluminum foil layer 514, and heat adhesive resin layer 515, of which the metal reinforcing layer 513 has a behavior of mechanically reinforcing the aluminum foil layer 514 fitted on its one face. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a battery such as a lithium secondary battery, and more particularly to a battery packaged with an aluminum laminate film and having improved waterproofness and impact strength.

  Since the lithium secondary battery needs to be kept in a state of being shielded from water, it is installed in a waterproof battery package. As such a battery package, a laminated film (hereinafter referred to as an aluminum laminate film) in which a base material layer, an aluminum foil layer, an intermediate layer, and a heat-adhesive resin layer are laminated in order from at least the outside from Patent Document 1 described later, In a battery package (battery container) formed by stacking the heat-adhesive resin layers so as to face each other and heat-sealing the edge portions in a bag shape, the inner side of the aluminum foil layer of the laminated film The intermediate layer is removed, the inside of the aluminum foil layer is formed of an adhesive layer and a heat-adhesive resin layer, and the thickness of the heat-adhesive resin layer of the heat-sealed portion at the edge of the laminated film is What is compressed by heat sealing and formed so as to be thinner than the thickness before heat sealing is known.

  Aluminum is used in the battery container of Patent Document 1 because it is lightweight and soft among various metals, and has a high spreadability and is easy to process. The thickness of the laminated film is usually about a few tens of μm, and the thickness of the aluminum foil therein is about 50 μm.

By the way, since the battery device having a lithium secondary battery packaged in a conventional aluminum laminate film is configured as described above, if it is accidentally dropped, the battery device receives an impact caused by dropping and is in the aluminum laminate film. The aluminum foil was broken due to its thinness and had a hole, and there was a problem that water vapor in the outside air entered from there. When water vapor enters the lithium secondary battery, the electrolytic solution is decomposed to become a gas, the volume expands, the internal pressure increases, and the battery package formed of the aluminum laminate film expands. As a solution to the above perforation problem, it is conceivable to increase the thickness of the aluminum foil, but since aluminum has low mechanical strength, there is a problem that the layer thickness needs to be considerably increased and the battery size increases. .
JP 2001-176466 A (Claim 1, FIGS. 1 to 3)

  The problem to be solved by the present invention is to develop a battery with improved impact resistance without substantially increasing the finished size of the battery packaged with an aluminum laminate film, in view of the above problems in the prior art. That is.

  The battery of the present invention is a battery packaged by an aluminum laminate film in which an aluminum layer is laminated with an organic polymer, and the aluminum layer includes a metal reinforcing layer that mechanically reinforces the aluminum layer. It is a feature.

  Since the aluminum layer includes a metal reinforcing layer that mechanically reinforces the layer, the impact resistance is improved without increasing the thickness of the aluminum laminate film, and the waterproof property is improved. A battery such as an excellent lithium secondary battery can be industrially produced.

Embodiment 1 FIG.
1 to 4 illustrate Embodiment 1 of the battery of the present invention. FIG. 1 is an external perspective view of a battery device 100 including a lithium secondary battery 4 as an example of the battery, FIG. 1 is an external perspective view of a packaged battery 3 included in FIG. 1, FIG. 3 is a cross-sectional view taken along line III-III in FIG. 2, and FIG. 4 is a partially enlarged view of FIG. 1 and 2, the battery device 100 includes a housing 1, a housing 2, and a built-in packaging battery 3, and the housing 1 is installed in the housing 2 with the packaging battery 3 installed in the housing 2. The housing 1 has a structure fitted to the housing 2 so as to cover from above, and the housing 1 is provided with connection windows of a positive terminal window 11, a negative terminal window 12, and a thermistor window 13.

  2 and 3, the packaging battery 3 includes a lithium secondary battery 4 (indicated by a dotted line in FIG. 2) and a battery package 5 that packages the lithium secondary battery 4. As shown in FIG. 3, the lithium secondary battery 4 includes four sheets of a separator 41, a negative electrode sheet 42, a separator 43, and a positive electrode sheet 44, and a negative electrode terminal 45 (see FIG. 2) is connected to the negative electrode sheet 42. The positive electrode sheet 44 has a structure in which the positive electrode terminal 46 (see FIG. 2) is connected and wound in a wound manner. In addition, the electrolyte solution is filled between the negative electrode sheet 42 and the positive electrode sheet 45.

  The battery package 5 is composed of an aluminum laminate film 51, which includes a base material layer 511, an adhesive layer 512, a metal reinforcing layer 513, an aluminum foil layer 514, and a heat as shown in FIG. An adhesive resin layer 515 is provided, and the base material layer 511 and the metal reinforcing layer 513 are bonded by an adhesive layer 512. The constituent material of the base material layer 511 and / or the thermoadhesive resin layer 515 corresponds to the organic polymer in claim 1.

  The metal reinforcing layer 513 is provided on one surface of the aluminum foil layer 514 and serves to mechanically reinforce the foil layer 514. The metal species of the metal reinforcing layer 513 received external force such as impact. There is no limitation as long as the aluminum foil layer 514 can be prevented from being perforated, and metals having a Young's modulus larger than the aluminum forming the aluminum foil layer 514 are used. As the aluminum, those well known or known in the art for aluminum laminate films can be used without limitation, but in particular, pure aluminum having a purity of 98 ± 1% by weight is preferable, and the metal is made of the pure aluminum. The Young's modulus is at least 1.2 times, preferably at least 1.5 times. Examples of such metals are iron, copper, brass, nickel, cobalt, gold, silver, titanium, etc. Among them, iron is particularly preferable from the viewpoints of hardness, Young's modulus, and impact resistance.

  When the effect of providing the metal reinforcing layer 513 is shown as an example using, for example, iron, the thickness of the aluminum foil layer 514 in the aluminum laminate film 51 of the conventional lithium secondary battery is about 50 μm. When an iron layer having a thickness of 5 μm corresponding to 10% of the thickness is employed as the reinforcing layer 513, even if the thickness of the aluminum foil layer 514 is half the above, that is, 25 μm, the Young's modulus of the laminate of both layers is thick. More than twice that of the 50 μm thick aluminum foil layer alone. Accordingly, regarding the thickness of the aluminum foil layer 514 and the metal reinforcing layer 513 in the present invention, the aluminum foil layer 514 is generally about 10 to 100 μm, preferably about 20 to 50 μm, and the metal reinforcing layer 513 is the aluminum foil layer 514. The thickness is about 0.5 to 20%, preferably about 1 to 15%.

  The laminate of the aluminum foil layer 514 and the metal reinforcing layer 513 can be manufactured by applying to one surface of the aluminum foil by electrolytic plating, electroless plating, ion plating, thermal spraying, vapor deposition, or other methods.

  In Embodiment 1, an example in which the metal reinforcing layer 513 is provided only on one surface of the aluminum foil layer 514 is shown, and the aluminum foil layer 514 is bonded to the base material layer 511 through the metal reinforcing layer 513 and the adhesive layer 512. However, in the present invention, the metal reinforcing layer 513 is provided on the surface of the aluminum foil layer 514 facing the heat-adhesive resin layer 515 as described above, and the aluminum foil layer 514 is interposed only through the adhesive layer 512. The metal layer 511 may be bonded to the base material layer 511, and further provided with metal reinforcing layers 513 on both surfaces of the aluminum foil layer 514, and the base material layer is interposed via any one of these metal reinforcing layers and the adhesive layer 512. 511 may be adhered. When the metal reinforcing layers 513 are provided on both surfaces of the aluminum foil layer 514, the thicknesses of the two metal reinforcing layers are not necessarily the same, but the total thickness of the two metal reinforcing layers is the above-described thickness. It is good to do so.

  The base material layer 511, the adhesive layer 512, and the heat-adhesive resin layer 515 may all be formed of materials known or known in the art. Note that the base material layer 511 may be formed of a thermoplastic resin so that thermal bonding can be performed, and the base material layer 511 may be formed of the same material as the thermal adhesive resin layer 515. When some materials are exemplified for each of the base material layer 511, the adhesive layer 512, and the thermal adhesive resin layer 515, the base material layer 511 includes polyesters such as polyethylene terephthalate and polybutylene terephthalate, and polyamides such as nylon. Film having excellent mechanical strength and chemical stability, or a biaxially stretched film thereof, the adhesive layer 512 is a two-component polyurethane, the thermal adhesive resin layer 515 is polyethylene, acid-modified Polyolefins such as polyethylene, polypropylene, acid-modified polypropylene, polybutene, and acid-modified polybutene, and acid-modified polyolefins.

  If a battery device having a conventional battery packaged with an aluminum laminate film is accidentally dropped, the battery package will be damaged by the contact between the case and the battery pack due to the impact when dropped. Water vapor or the like in the atmosphere enters the inside and generates heat, and the electrolytic solution decomposes and vaporizes to expand in volume, and in some cases, may explode. On the other hand, in the battery device 100 of the first embodiment, since the aluminum foil layer 514 is reinforced by the metal reinforcing layer 513, the battery packaging body 5 is not easily damaged by the impact at the time of dropping as described above. The battery 4 is protected from water vapor in the atmosphere, and the above accident is avoided. Further, by providing the metal reinforcing layer 513, the thickness of the aluminum foil layer 514 can be reduced based on the strength of the metal reinforcing layer 513, and hence the thickness of the aluminum laminate film 51 can be reduced. There is also an effect that can be downsized.

  The battery of the present invention is useful as a lithium secondary battery excellent in impact resistance.

1 is a perspective view of a battery device including a lithium secondary battery as an example of a battery in Embodiment 1. FIG. It is an external appearance perspective view of the package battery contained in FIG. It is sectional drawing along the III-III line of FIG. FIG. 4 is a partially enlarged view of FIG. 3.

Explanation of symbols

100 battery device, 1 housing, 11 positive terminal window, 12 negative terminal window,
13 Thermistor window, 2 housing, 3 packaging battery, 4 lithium secondary battery,
41 separator, 42 negative electrode sheet, 43 separator, 44 positive electrode sheet,
45 negative terminal, 46 positive terminal, 5 battery pack,
51 Aluminum laminate film, 511 base layer, 512 adhesive layer,
513 Metal reinforcing layer, 514 Aluminum foil layer, 515 Thermal adhesive resin layer.

Claims (5)

  A battery packaged with an aluminum laminated film in which an aluminum layer is laminated with an organic polymer, wherein the aluminum layer includes a metal reinforcing layer that mechanically reinforces the aluminum layer.   2. The battery according to claim 1, wherein the aluminum layer has a thickness of about 10 to 100 [mu] m, and the metal reinforcing layer has a thickness of about 0.5 to 20% of the thickness of the aluminum layer.   The aluminum layer is made of pure aluminum having a purity of 98 ± 1% by weight, and the metal reinforcing layer is made of a metal having a Young's modulus of at least 1.2 times that of the pure aluminum. The battery according to claim 1 or 2.   The battery according to claim 3, wherein the metal is iron.   The battery according to any one of claims 1 to 4, wherein the battery is a lithium secondary battery.

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