JP2000173564A - Thin battery bag body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bag body having a superior perforation resistance against the impact such as falling, collision, etc., and pressure, etc., by a pointed material by forming an elastic thin film with its stuck thereto by the bag body in the whole face at least one of the front and rear of the bag body. SOLUTION: A film base material constituted of a prescribed-thickness inside resin layer 3 composed of denaturated polypropylene, a prescribed-thickness intermediate metal layer 4 composed of aluminum foil, and a prescribed- thickness outer rubber layer (elastic thin layer) 6 composed of hydrogenation NBR bonded and fixed to the whole surface of the intermediate metal layer 4 via an urethane-based adhesive material layer 5 is used for a laminate material 2 constituting this thin-type battery bag body 1 so as to be formed into a rectangular bag body by a four-side sealing method. The four sides are sealed by heating with a power-generating element arranged between two laminate materials 2 and the electrode of the power generating element is projected from one side of the heat seal part. The outer rubber layer 6 is provided on the whole face of the surface of the bag body 1 so that the impact absorbing property can be drastically increased while holding the flexibility of the bag body 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thin battery bag for housing a power generating element for a thin battery such as a lithium polymer secondary battery.

[0002]

2. Description of the Related Art With the recent development of various electronic devices, there is an increasing need for miniaturization and space saving of electronic devices. Flexibility is required. At present, lithium polymer secondary batteries using gel electrolytes aiming at thinning are entering the stage of practical use, and lithium polymer secondary batteries, which are all polymerized including the cathode and anode materials, are also under development. .

FIGS. 10 and 11 show an example of the structure of a lithium polymer secondary battery (the cathode material is not polymerized). In the figure, 21 is a positive electrode current collector (aluminum foil), 22 is a positive electrode (a lithium-containing composite oxide such as lithium cobalt oxide), 23 is a separator (polymer electrolyte plasticized with a solvent), and 24 is a negative electrode (charcoal). Material), 2
Reference numeral 5 denotes a negative electrode current collector (copper foil), and these power generating elements are housed in a housing means 26 (in this structural example, a thin laminated material is used as the housing means 26). 26a is a heat seal portion formed on the outer peripheral portion of the storage means 26, and 27 is an electrode.

In such a lithium polymer secondary battery, the power generating element can be made flexible and the danger of liquid leakage is low, so that the power generating element is housed in a thin laminated material as in the above structural example. can do. For example, in JP-A-9-7636, a three-layer laminate foil of a polyethylene layer, an aluminum foil layer, and a polyethylene layer is used as a laminate material. Then, such a thin battery of a laminate type is incorporated in an electronic device as it is or in a state of being stored in a hard case. Further, in Japanese Patent Application Laid-Open No. 61-256559, in a flat type battery, a polymer thin film is coated on an outer surface excluding a peripheral portion thereof, whereby a pressure is applied from the outside by a sharp object such as a ballpoint pen. This also prevents the internal battery power generation element from being damaged.

[0005]

However, in order to meet the needs for further miniaturization and space saving of electronic equipment, it is necessary to insert a laminated thin battery into a narrow dead space. If there is no elastic body in the peripheral portion, the body of the thin battery, especially the bottom, may hit a protrusion inside the electronic device during the insertion, thereby causing a hole in the laminate and causing a break in the laminate. In addition, the inside of the laminated material may be damaged by the collision with the protrusion inside the electronic device, the falling of the thin battery during the manufacturing process or transportation, the collision with other objects, and the drop impact of the entire device during the use of the electronic device. There is also a risk that the laminate material may break, such as when the power generation element is strongly hit and a hole is made in the laminate material at the corner. Therefore, by increasing the thickness of the metal foil constituting the laminate or protecting it with a robust box, the perforation resistance of the laminate can be improved. No longer available.

The present invention has been made in view of such circumstances, and it has been proposed to increase the thickness of a metal foil constituting a laminate material,
It is an object of the present invention to provide a thin battery bag having good perforation resistance against impacts such as dropping and collision, pressure from sharp objects, and the like without being protected by a robust box.

[0007]

In order to achieve the above object, a thin battery bag of the present invention is a bag for accommodating a power generating element for a thin battery. The elastic thin layer is formed on at least one of the entire surfaces in close contact with the bag.

That is, the thin battery bag of the present invention has an elastic thin layer formed on the entire surface of at least one of the front surface and the back surface in a state of being in close contact with the bag. The shock absorption of the thin battery bag is greatly improved (especially due to the elastic thin layer formed on the peripheral edge of the one surface), and the thin battery bag maintains the effect of flexibility while preventing dropping and collision. The impact can be received and absorbed by the elastic thin layer. Therefore, when inserted into an electronic device, it may hit a protruding portion inside the electronic device, drop the thin battery during the manufacturing process or during transportation, hit another object, or drop the entire device while using the electronic device. However, there is no danger of the electrolyte material being volatilized or leaking because there is no risk of the laminate material being broken, such as a hole being opened in the laminate material. I will not invite you. Moreover, even if the body of the laminated material is pierced with a sharp object by the elastic thin layer (particularly by the elastic thin layer formed on the body part on one side), the sharp object is laminated by the elastic thin layer. It is difficult to penetrate the material, and even if a sharp object is pulled out, the elastic thin layer is restored and the hole is closed when a sharp object is removed, so in this case (when the body of the laminate material is pierced with a sharp object) Also, there is no danger of volatilization or leakage of the electrolytic solution, and no deterioration of battery performance is caused by intrusion of moisture from the outside. In addition, the surface (ie, outer layer) of the thin battery bag
When an elastic thin layer is formed on the thin battery bag, fixing stability when the thin battery bag is stored inside the electronic device is improved,
There is no rattling inside the electronic device, and the power generating elements and the like in the thin battery bag are not broken for a long time.

In the present invention, when the above-mentioned elastic thin layer is a rubber layer or a thermoplastic elastomer layer, the rubber layer or the thermoplastic elastomer layer is excellent in shock absorbing properties and also excellent in flexibility. Ideal as a layer.

In the present invention, when the inner layer of the bag is made of a heat-sealing resin layer and the elastic thin layer formed on the surface of the bag is made of an insulating layer that does not melt during heat sealing, Good heat sealing can be performed even when a bag body is produced by joining a laminate material having a thin layer formed thereon by heat sealing.

Next, the present invention will be described in detail.

The thin battery bag of the present invention has an elastic thin layer formed on at least one of the front surface and the back surface.

The portion where the elastic thin layer is formed may be the entire surface of the thin battery bag, the entire back surface, or the entire front and back surfaces.

The thickness of the elastic thin layer is 0.03 mm to 2 mm.
mm, preferably 0.08 mm to 1 m
m. The above thickness is 0.03mm
If it is less than 2, the effect of increasing the shock absorption cannot be obtained, and if it exceeds 2 mm, the effects of lightness and flexibility cannot be obtained. Further, when the thickness is set in the range of 0.08 mm to 1 mm, the lower limit of the thickness exceeds 0.03 mm, and the effect of increasing shock absorption is improved, and the thickness is reduced. Is less than 2 mm, and the effects of lightness and flexibility are improved.
Moreover, even if the tip of a needle or the like is pierced with a sharp tip, it is difficult to penetrate the laminate material.

The laminating material constituting the thin battery bag is usually composed of a metal layer, an inner resin layer formed on the inner surface of the metal layer (which acts both as an insulating layer and a sealant), and It consists of a film substrate with an outer resin layer formed on the outer surface of the layer. Aluminum, aluminum alloy, copper, copper alloy, and the like for the metal material constituting the above-mentioned metal layer are excellent in blocking gas such as moisture and oxygen.
Iron, stainless steel foil, titanium, titanium alloy, etc. are used.
Although it is formed into various forms such as foil, aluminum foil is preferred in terms of light weight and low cost.

The resin material constituting the inner resin layer is polypropylene (PP), polyethylene (P
E), denatured polypropylene, polyester, polyacrylonitrile, polyvinyl acetate, vinyl acetate, polyamide, tetrafluoroethylene resin (PTFE), vinylidene fluoride resin (PVDF), etc. are used. From the viewpoint of sealing properties, modified polypropylene is preferable. Various materials are used as the resin material forming the outer resin layer. Usually, the same material as the resin material forming the inner resin layer is used. The thickness of such a laminate is set in the range of 12 μm to 150 μm.

As the elastic material constituting the elastic thin layer, a rubber material or a thermoplastic elastomer material is used. As the rubber-based material, NBR, NR, E
PDM, SBR, butyl rubber, silicone rubber, and the like are used, and as a rubber-based adhesive, a reactive substance such as a urethane-based, epoxy-based, silicone-based, or silane coupling material to rubber is used. On the other hand, olefin-based elastomers, styrene-based elastomers and the like are used as the thermoplastic elastomer-based materials, and modified olefin-based elastomers and modified styrene-based elastomers are used as the thermoplastic elastomer-based adhesive. When such an elastic thin layer is formed on the surface of the laminate (that is, the outer layer), the outer resin layer can be omitted. The resin layer can be omitted.

By forming such a thin battery bag into a corrugated shape, the flexibility can be enhanced. In this case, after laminating the laminate material, the surface of the laminate material,
An elastic thin layer may be pressure-bonded to the back surface or both surfaces via an adhesive, or an elastic thin layer may be formed on the front surface, the back surface, or both the front and back surfaces of the laminate, and then processed into a waveform. For example, when a rubber layer is provided as an elastic thin layer, the laminate may be corrugated after rubberization, or may be rubberized after corrugation of the laminate, or after corrugation of the laminate. A rubber paste mixed with an adhesive may be applied, heated, dried and vulcanized.

[0019]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a partial sectional view showing an embodiment of the thin battery bag 1 of the present invention. In this embodiment,
As a power generating element for a thin battery (not shown), a power generating element of a lithium polymer secondary battery using a gel polymer electrolyte composed of a positive electrode current collector 21 to a negative electrode current collector 25 of FIG. 11 is used. . The size of this power generation element is usually
It is about 40 mm x 80 mm x 2 mm (thickness). In addition, as the laminate 2 constituting the thin battery bag 1, modified polypropylene (QF551 manufactured by Mitsui Chemicals, Inc.) is used.
A 30 μm-thick inner resin layer 3 made of aluminum foil, a 30 μm-thick intermediate metal layer 4, and a hydrogenated NBR bonded and fixed to the entire surface of the intermediate metal layer 4 via a urethane-based adhesive layer 5. A film base made of an outer rubber layer (elastic thin layer) 6 having a thickness of 200 μm is used, and is formed into a rectangular bag by a four-side sealing method as shown in FIG. That is, the two laminated materials 2 are superposed face to face, and the opened four sides are heat-sealed. In this molding, usually
In a state where the power generating element is arranged between the two laminate materials 2,
The four sides are heat-sealed, and the electrode 27 of the power generation element is projected from one side of the heat seal portion 26a to the outside (FIG. 10).
reference).

As described above, in this embodiment, since the outer rubber layer 6 is provided on the entire surface of the thin battery bag 1, the flexibility of the thin battery bag 1 is maintained. Even when the power generating element is stored in the thin battery bag body 1 and dropped, the outer rubber layer 6 absorbs the shock and the shock absorbing property is greatly increased. There is almost no hole in the body 1. Moreover, even if the body or the like of the laminated material 2 is pierced with a needle or the like, the needle or the like does not easily penetrate the laminated material 2. Restores quickly and plugs the hole.

FIG. 2 is a partial sectional view showing another embodiment of the thin battery bag 1 of the present invention. In this embodiment, the laminated material 2 shown in FIG.
A wave shape with a wave height of 0.4 mm is given,
The flexibility is further enhanced. Other parts are the same as those of the above-described embodiment, and the same parts are denoted by the same reference numerals. In this embodiment, the same operation and effect as those of the above embodiment can be obtained. Moreover, since the laminate 2 is formed in a corrugated shape, it has flexibility, stretchability,
Excellent flexibility.

FIG. 3 is a partial sectional view showing still another embodiment of the thin battery bag 1 of the present invention. In this embodiment, in the embodiment shown in FIG. 2, instead of the inner resin layer 3 of the laminate 2, an olefin-based An inner rubber layer 8 made of an elastomer and having a thickness of 30 μm is provided. Other parts are the same as those of the embodiment shown in FIG. 2, and the same parts are denoted by the same reference numerals. In this embodiment, the same operation and effect as those of the embodiment shown in FIG. Moreover, in this embodiment, since the inner rubber layer 8 is also provided on the back surface of the thin battery bag 1, the hole resistance test is improved as compared with the embodiment shown in FIG. Further, the heat sealability was equivalent to that of the conventional product, and a good heat seal force was obtained at 160 ° C. × 10 sec.

[0024]

Example Products 1 and 2 and Comparative Examples 1 and 2 A thin battery bag 1 having the structure shown in FIG. 2 was prepared as Example Product 1, and a thin battery having the structure shown in FIG. A battery bag 1 was prepared. Also, as Comparative Example Product 1, a 30 μm thick inner resin layer (manufactured by Mitsui Chemicals, Inc.) on the inner surface of a 30 μm thick intermediate metal layer (aluminum foil) via a urethane-based adhesive layer
QF551), and a laminate material in which an outer resin layer (PP) having a thickness of 30 μm is provided on the outer surface of the intermediate metal layer via a urethane-based adhesive layer (not formed into a wavy shape)
A thin battery bag (not shown) was prepared. Further, as a comparative example product 2, a thin battery bag (not shown) in which an outer rubber layer is provided only in a portion except for a peripheral portion (all four sides) in the thin battery bag 1 having the structure shown in FIG. Prepared. Using Examples 1 and 2 and Comparative Examples 1 and 2, the puncture resistance (drop puncture resistance, body part damage resistance, needle stick resistance) and flexibility were examined.

With respect to the above-mentioned drop hole resistance (the hole is hard to be opened at the corner of the laminate 2 due to the shock absorbing property of the outer rubber layer 6 even if it falls), the number of drops until the hole is opened in the laminate 2 is Examined. That is, as shown in FIG. 4, the thin battery bag 1 containing the power generation element is
Drop from a height of 80 cm above 1 (2 cm thick). At the time of this drop, the inside of the cylindrical body 12 is dropped vertically so that the corners of the thin battery bag 1 hit the aluminum plate 11 (Experiment 1).

As shown in FIG. 5, for the above-mentioned body part scratch resistance (a hole is not easily opened in the body part of the laminated material 2 due to the shock absorbing property of the outer rubber layer 6 even when a sharp object is hit), as shown in FIG. The thin battery bag 1 containing the power generating element is placed on the plate 13, the cylindrical body 14 is placed at the center of the body of the thin battery bag 1, and the tip R (R) is formed at a tip angle of 90 degrees. The triangular pyramid 15 is set in the cylindrical body 14 such that the tip of the 1-cm triangular pyramid 15 is in contact with the body of the thin battery bag 1, and the triangular pyramid 15 is placed at a height of 80 cm above the triangular pyramid 15. The weight 16 is dropped on the cone 15 (Experiment 2).

Needle puncture resistance (Even if the body of the laminate 2 is pierced with a needle and penetrated, when the needle is removed, the outer rubber layer 6 is restored to close the hole, so that leakage of electrolyte or the like, Regarding prevention of infiltration of moisture), the needle 17 is pierced through the laminate material 2 of the thin battery bag 1 so as to penetrate (see FIG. 6).
FIG. 6 shows an example product 2 in which the needle 17 is penetrated. Then, using this test piece, the amount of water (mg / day) in the container 18 after 24 hours is examined by the apparatus shown in FIG. 7 (Experiment 3).

With respect to the above flexibility, both sides of each thin battery bag 1 are bent, and the radius of curvature of the curved portion when each thin battery bag 1 is folded is measured. as a result,
In Example product 1, no fold occurred at a radius of curvature of 10 mm, whereas in Example product 2, both sides were approximately 5 mm.
When it was bent to the extent, it was broken and cracks occurred in the intermediate metal layer. In the comparative example 1, both sides are about 3 mm.
When it was bent to the extent, it was broken and cracks occurred in the intermediate metal layer. In Comparative Example 2, both sides are about 5 mm.
When it was bent to the extent, it was broken and cracks occurred in the intermediate metal layer. Table 1 below shows the experimental results of such puncture resistance and flexibility.

[0029]

[Table 1]

As is evident from Table 1 above, Examples 1 and 2 are superior to Comparative Examples 1 and 2 in terms of perforation resistance and flexibility. In particular, with regard to flexibility, it can be seen that the product of Example 1 is very excellent.

In the embodiment shown in FIG. 1, the elements shown in the configuration of the positive electrode current collector 21 to the negative electrode current collector 25 in FIG. 11 are used as the power generation elements for the thin battery, but the power generation element is not limited to this. Instead, various power generation elements can be used.

Further, in the embodiment shown in FIG. 1, the outer rubber layer 6 is provided on the surface of the laminate 2, but a rubber layer may be provided on the back of the laminate 2. In this case, a rubber layer can be provided on the inner surface of the inner resin layer 3, or a rubber layer can be provided instead of the inner resin layer 3. In the embodiment shown in FIGS. 1 and 3, the outer rubber layer 6 is provided on the surface of the intermediate metal layer 4, but the outer rubber layer 6 may be provided via a resin layer. In the embodiment shown in FIG. 3, the inner rubber layer 8
However, the inner rubber layer 8 may be provided via the inner resin layer 3.

When the thin battery bag 1 is formed, a three-way seal (one laminated material 2 is folded at the center and overlapped, and the opened three sides are heat-sealed, etc.), a pillow type Center seal method (a single laminated material is formed into a cylinder with the back surfaces of both ends overlapped, and the overlapped portion is heat-sealed, and then the openings at both ends of the cylinder are heat-sealed, etc. Do),
Pillow-type envelope method (The difference from the pillow-type center seal method is that when one laminated material 2 is formed into a cylindrical body, the back surface of one end is superimposed on the surface of the other end, so that both the front and back surfaces are used. In this case, a thin elastic layer such as the rubber layers 6 and 8 can be formed.

[0034]

As described above, according to the thin battery bag of the present invention, the elastic thin layer is formed on the entire surface of at least one of the front surface and the back surface in a state of being in close contact with the bag. Therefore, the elastic thin layer (especially by the elastic thin layer formed on the peripheral portion of the one surface) greatly improves the shock absorption of the thin battery bag, and maintains the effect of flexibility. Also, the impact such as a drop or a collision can be received and absorbed by the elastic thin layer. Therefore, when inserted into an electronic device, it may hit a protruding portion inside the electronic device, drop the thin battery during the manufacturing process or during transportation, hit another object, or drop the entire device while using the electronic device. However, there is no danger of the electrolyte material being volatilized or leaking because there is no risk of the laminate material being broken, such as a hole being opened in the laminate material. I will not invite you. Moreover, even if the body of the laminated material is pierced with a sharp object by the elastic thin layer (particularly by the elastic thin layer formed on the body part on one side), the sharp object is laminated by the elastic thin layer. It is difficult to penetrate the material, and even if a sharp object is pulled out, the elastic thin layer is restored and the hole is closed when a sharp object is removed, so in this case (when the body of the laminate material is pierced with a sharp object) Also, there is no danger of volatilization or leakage of the electrolytic solution, and no deterioration of battery performance is caused by intrusion of moisture from the outside. Furthermore, when an elastic thin layer is formed on the surface (ie, outer layer) of the thin battery bag, the fixing stability when the thin battery bag is stored inside the electronic device is improved, There is no rattling inside, and the power generating elements and the like in the thin battery bag are not broken for a long period of time.

In the present invention, when the elastic thin layer is a rubber layer or a thermoplastic elastomer layer,
Since the rubber layer or the thermoplastic elastomer layer has excellent shock absorbing properties and excellent flexibility, it is most suitable as an elastic thin layer.

In the present invention, when the inner layer of the bag is made of a heat-sealing resin layer and the thin elastic layer formed on the surface of the bag is made of an insulating layer that does not melt during heat sealing, Good heat sealing can be performed even when a bag body is produced by joining a laminate material having a thin layer formed thereon by heat sealing.

[Brief description of the drawings]

FIG. 1 is a partial sectional view showing one embodiment of a thin battery bag according to the present invention.

FIG. 2 is a partial cross-sectional view showing another embodiment of the thin battery bag of the present invention.

FIG. 3 is a partial sectional view showing still another embodiment of the thin battery bag of the present invention.

FIG. 4 is an explanatory diagram showing the method of Experiment 1.

FIG. 5 is an explanatory diagram showing a method of Experiment 2.

FIG. 6 is an explanatory diagram showing the method of Experiment 3.

FIG. 7 is an explanatory diagram showing the method of Experiment 3.

FIG. 8 is an explanatory diagram showing a method for checking flexibility.

FIG. 9 is an explanatory diagram showing a method for checking flexibility.

FIG. 10 is a perspective view showing a structural example of a lithium polymer secondary battery.

FIG. 11 is a cross-sectional view showing a main part of the structure example.

[Explanation of symbols]

 1 Thin battery bag 6 Outer rubber layer

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 AA06 AA10 AA13 CC02 CC10 CC12 DD13 DD21 5H029 AJ12 AL12 BJ04 CJ05 DJ01 DJ02 DJ03 EJ12

Claims (3)

[Claims] 1. A bag for accommodating a power generating element for a thin battery, wherein an elastic thin layer is formed on the entire surface of at least one of a front surface and a back surface of the bag in a state of being in close contact with the bag. A bag for a thin battery, comprising: 2. The thin battery bag according to claim 1, wherein the elastic thin layer is a rubber layer or a thermoplastic elastomer layer. 3. The thin battery according to claim 1, wherein the inner layer of the bag is made of a resin layer having heat sealing properties, and the elastic thin layer formed on the surface of the bag is made of an insulating layer that does not melt during heat sealing. Bags.