JP3050157B2 - Non-aqueous electrolyte battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a non-aqueous electrolyte battery used as a power source for electronic equipment. More specifically, the positive electrode, the negative electrode, the electrolyte is sealed in an encapsulating bag, and has a structure in which the lead wires of the positive electrode and the negative electrode are respectively taken out,
In addition, it has a highly reliable structure for sealing the electrolyte.

[0002]

2. Description of the Related Art Along with the miniaturization of electronic devices, there is an increasing demand for miniaturization and weight reduction of batteries as power sources. On the other hand, batteries are also required to have higher energy density and higher energy efficiency, and expectations for secondary batteries such as Li-ion batteries are increasing. In response to such demands, for example, as seen in JP-A-61-240564, a group of electrode plates is inserted into a bag made of an acid-resistant thermoplastic resin, and a large number of the electrode groups are formed into a film or sheet. There has been proposed an attempt to form a sealed lead-acid battery by enclosing it in a bag-like outer body made of a tubular or tubular synthetic resin. Also, Japanese Patent Application Laid-Open No.
As disclosed in Japanese Patent No. 2447 and Japanese Patent Application Laid-Open No. 57-115820, there is also an attempt to improve the sealing performance by forming a structure in which a metal layer is sandwiched between plastic films in a sheet of an enclosing bag.

[0003]

The provision of a metal layer greatly improves the sealing performance, but does not completely prevent the penetration of moisture from the sealing portion. When moisture enters, it reacts with the electrolytic solution to generate hydrofluoric acid, and this hydrofluoric acid may permeate the plastic film layer and corrode the metal layer, or may cause separation between the metal layer and the plastic layer. The present invention uses a non-aqueous electrolyte battery encapsulation bag that does not corrode the metal layer or cause peeling between the metal layer and the plastic film layer even when moisture invades and generates hydrofluoric acid. An object is to provide an electrolyte battery.

[0004]

Means for Solving the Problems As a result of intensive studies to attain the above object, the present inventors have found that if at least one of the plastic layers is provided with an acid permeation preventing means, the formation of hydrofluoric acid can be prevented. Without corroding the metal layer,
It has also been found that no delamination occurs between the metal layer and the plastic film layer.

The gist of the present invention is as follows. Positive electrode,
A nonaqueous electrolyte battery having a structure in which a negative electrode, an electrolytic solution, and the like are sealed in an enclosing bag, and a positive electrode and a negative electrode lead are respectively taken out of the nonaqueous electrolyte battery. And a laminated sheet of a metal layer and one or more plastic layers, wherein at least one of the plastic layers is provided with an acid permeation preventing means. As a means for preventing permeation of acid, for example, a metal carboxylate or a metal oxide can be contained in the resin. Also,
As the metal carboxylate or metal oxide, one or more mixtures selected from the group consisting of calcium carbonate, magnesium oxide, hydrotalcites and calcium stearate are effective.

The problem and the solution will be described in more detail.
As an example of the configuration of the enclosing bag, there can be cited one in which a PET film is attached to the outer surface of an aluminum foil and a thermoplastic resin such as polyethylene is attached to the inner surface. The PET on the outer surface is provided to protect aluminum from external damage, and the polyethylene on the inner surface is provided for heat sealing. When such a conventionally devised material is used, moisture gradually penetrates during long-term storage even when heat-sealing, and the water reacts with the electrolyte solution sealed in the bag. To produce hydrofluoric acid. This hydrofluoric acid has a problem in that it permeates polyethylene and the like and peels off the adhesive interface between aluminum and polyethylene, which is one of the factors that make such a bag-type battery container not practical.

In order to solve this problem, it is possible to develop a material that does not allow moisture to penetrate at all, or to provide a resin layer that does not allow hydrofluoric acid to permeate even if moisture enters and hydrofluoric acid is generated. Good. As a result of examining the provision of a resin layer that does not allow hydrofluoric acid to pass therethrough, it was found that the object can be achieved by the above-described method. That is, a method in which an acid generated by adding a metal carboxylate or a metal oxide to a resin is trapped on the way. As the carboxylate metal salt and metal oxide, the above-mentioned calcium carbonate, magnesium oxide, hydrotalcites, calcium stearate and the like are preferable, but other stabilizers for polyvinyl chloride are also effective. The resin containing these is preferably polyethylene, polypropylene, or their acid-modified products, ionomers, and the like that are not easily attacked by the electrolyte solution. What is necessary is just to provide the resin layer which is hardly attacked.

[0008]

The present invention will be described below with reference to examples and comparative examples. Note that these examples do not limit the present invention. Sheets having the configuration shown in Table 1 are formed into two rectangular sheets (7
(0 mm x 135 mm), the PET faces facing each other, and the three sides of the rectangle were heat-sealed with a width of 5 mm to create an enclosing bag, which was used for the experiment. In order to investigate the influence of the heat seal layer, the composition of the heat seal layer was variously changed.

[0009]

[Table 1]

[0010]

[Table 2]

Example 1 The composition of A in Table 2 was used as the composition of the heat seal layer.

Example 2 The composition of B in Table 2 was used as the composition of the heat seal layer.

Example 3 The composition of C in Table 2 was used as the composition of the heat seal layer.

Example 4 The composition of D in Table 2 was used as the composition of the heat seal layer.

Comparative Example The composition of E in Table 2 was used as the composition of the heat seal layer.

On the other hand, 100 parts by weight of LiCoO ₂ powder
10 parts by weight of graphite and 10 parts by weight of polyvinylidene fluoride were mixed, dissolved in N-methyl-2-pyrrolidone, and then made into a paste. Next, apply this paste to a thickness of 20
It was coated on one side of a μm aluminum foil, dried and then roller pressed. Thus, a thickness of 0.1 mm, a width of 50 mm,
An electrode plate having a length of 105 mm (5 mm is an uncoated portion) was prepared and used as a positive electrode.

Further, 20 parts by weight of polyvinylidene fluoride was mixed with 100 parts by weight of phosphorous natural graphite powder, dissolved in N-methyl-2-pyrrolidone, and then formed into a paste. This paste was applied on both sides of a copper foil having a thickness of 20 μm, dried, and then roller-pressed. Thus, an electrode plate (5 mm thick, 50 mm wide, 105 mm long)
mm is an uncoated part) to prepare a negative electrode.

Next, aluminum, which is a conductor of a lead wire, was ultrasonically welded to a portion of the aluminum foil where the active material of the positive electrode was not formed. Similarly, copper, which is a conductor of a lead wire, was ultrasonically welded to a portion of the copper foil where the active material of the negative electrode was not formed.

The two electrodes, each having a lead wire connected to the encapsulating bag according to the configuration of the embodiment and the comparative example, are inserted in a state where a polyolefin porous membrane is disposed between the two electrodes, and then 8 cc of the electrolytic solution is applied. Injected. As the electrolytic solution, a mixture of ethylene carbonate and diethyl carbonate at a volume ratio of 1: 1 and lithium hexafluorophosphate dissolved at 1 mol / liter was used.

Thereafter, the lead wire was taken out from the opened portion of the sealed bag, and the insulation of the lead wire and the inside of the sealed bag and the inside of the opened portion of the sealed bag were heat-sealed at 150 ° C. (seal width: 10 mm). . A test battery was completed according to the above procedure.

[0021]

The effects of the present invention were confirmed by a constant temperature test as follows. The battery prepared as described above was measured for weight change, appearance change and hydrofluoric acid concentration in the electrolytic solution after being kept in a thermostat at 85 ° C. for 720 hours, and by titration with 0.1N NaOH.

The results are as shown in Table 3. In Examples 1 to 4, no change was observed in the appearance even though hydrofluoric acid was generated to some extent. On the other hand, in Comparative Example 1, since the generated hydrofluoric acid corroded the aluminum foil, the sealing portion of the sealing bag was peeled off. Therefore, in the example, the heat sealing layer adsorbs the generated hydrofluoric acid, and as a result, has an effect of protecting the aluminum foil. According to the present invention, the sealing reliability of the sealed bag is significantly improved. I understand.

[0023]

[Table 3]

[Brief description of the drawings]

FIG. 1 shows a non-aqueous electrolyte battery using a sealed bag and a lead wire of the present invention.

FIG. 2 schematically shows the inside of an enclosing bag.

FIG. 3 shows a cross section of an enclosing bag.

FIG. 4 is an enlarged view of a heat sealing portion of the enclosing bag.

[Explanation of symbols]

 1, 1 ': conductor of lead wire 2, 2': insulation of lead wire 3: sealed bag 4: sealed portion of sealed bag (example) 5, 5 ': electrode 6: diaphragm 7: positive electrode current collector 7': Negative electrode current collector 8: Positive electrode active material 8 ': Negative electrode active material 9: Aluminum foil 10: Insulating outer layer (insulation for electrode lead) 11: Thermoplastic layer 12: PET layer

──────────────────────────────────────────────────続 き Continuation of front page (72) Inventor Keiichi Tanaka 1-3-1 Shimaya, Konohana-ku, Osaka-shi, Osaka Sumitomo Electric Industries, Ltd. Osaka Works (56) References JP-A-8-83596 (JP, A JP-A-10-208709 (JP, A) JP-A-61-116071 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01M 2/02 H01M 2/06

Claims (2)

(57) [Claims] 1. A positive electrode, a negative electrode, electrolyte and the like is sealed encapsulating bag, a nonaqueous electrolyte battery is taken out the lead wire of the positive electrode and the negative electrode respectively external, even the sealed bag the lead wire enclosed Which is composed of a laminated sheet of a metal layer and a plastic layer composed of one or more layers.
At least one of the plastic layers contains a metal carboxylate or a metal oxide as a means for preventing permeation of acid.
Nonaqueous electrolyte battery, characterized in that allowed to. 2. The carboxylic acid metal salt or metal oxidation
Calcium carbonate, magnesium oxide, hydrotal
Sites, 1 selected from the group of calcium stearate
2. A mixture of at least one species or a mixture of several species.
3. The non-aqueous electrolyte battery according to claim 1.