JPH09171803A - Manufacture of sealing packing for battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the leakage resisting performance of a battery by dry- mixing liquefied pitch fluoride obtained by reacting pitch fluoride with fluorine gas into a synthetic resin, and molding the resulting mixture. SOLUTION: As a sealing packing for battery, liquefied pitch fluoride obtained by reacting pitch fluoride with fluorine gas is dry-mixed to a synthetic resin. The resulting mixture is molded into a prescribed form by a molding machine to form the sealing packing 3 for battery. Otherwise, the mixture obtained by dry-mixing the liquefied pitch fluoride obtained by reacting pitch fluoride with fluorine gas into the synthetic resin is molded in a prescribed form on the periphery of either one of positive electrode and negative electrode metal vessels 1, 8 by means of molding machine. The atomic ratio F/C of carbon atom C to fl-uorine atom F in the liquefied pitch fluoride is preferably 1.8-2.3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a battery sealing packing and a battery using this sealing packing.

[0002]

2. Description of the Related Art In sealing a battery, an electrolytic sealing packing of nylon, polypropylene or the like is placed between a metal container that also serves as a positive electrode terminal and a negative electrode terminal, and the sealing packing and the positive and negative electrode containers are pressure-bonded to each other to prevent electrolysis. Prevents leakage of liquid. In addition, some battery systems are often used as a power source for memory backup as a part of electronic equipment under a severe environmental condition for a long period of time, and further improvement measures are needed. Therefore, the following improvements have been made to the battery sealing portion.

(1) A method by so-called insert molding in which a synthetic resin and a synthetic rubber are integrally molded and attached to the periphery of a metal container which also serves as a positive electrode terminal and a negative electrode terminal without forming a gap.

(2) A method in which a metal container which also serves as a positive electrode terminal and a negative electrode terminal and a separate sealing packing are fitted together, and a sealing material is interposed at the fitting contact portion to form a sealing body.

[0005]

However, (1)
In this method, the phenomenon of displacement occurs due to the stress during crimping when constructing the battery, and as a result, a gap is created between the metal container also serving as the positive electrode terminal and the negative electrode terminal and the sealing packing, and the airtight sealing port cannot be expected. In the method (2), the application space of the sealing material is extremely small as the battery becomes thinner and smaller, and when a large amount of the sealing material is applied, the sealing material may scatter or adhere to the terminal surface of the battery. Is not preferable.

[0006]

In order to solve these problems, the present invention provides a liquid obtained by reacting fluorinated pitch with fluorine gas on the peripheral portion of one of the positive and negative metal containers. Molding a dry mixture of fluorinated pitch in a synthetic resin into a predetermined shape by a molding machine,
Alternatively, a dry mixture of synthetic fluoride and liquid fluoride pitch obtained by reacting pitch fluoride with fluorine gas is applied to the peripheral edge of one of the positive and negative metal containers by a molding machine. The above-mentioned shape is integrally molded by insert molding to form a battery sealing packing. The liquid fluorinated pitch that can be used here has an atomic ratio F / C of carbon atoms (C) to fluorine atoms (F) of 1.
8 to 2.3, fluorinated pitch to synthetic resin 2 to 7
It is preferred to use wt%.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The use of a liquid fluorinated pitch in which the atomic ratio F / C of carbon atoms (C) and fluorine atoms (F) is 1.8 to 2.3 is the atomic ratio F / C. Is less than 1.8, the kinematic viscosity of the fluorinated pitch is extremely low, from several centimeters to several tens of centistokes, and the liquid is so dry that it is difficult to evenly adhere it to the surface of the synthetic resin pellets. If the atomic ratio F / C is more than 2.3, a blocking phenomenon occurs in which pellets stick to each other during mixing with synthetic resin pellets, which is not preferable because of poor workability. Also,
When the fluorinated pitch is used in an amount of 2 to 7% by weight relative to the synthetic resin, the sealing effect cannot be sufficiently exhibited when the amount is 2% by weight or less, and the sealing packing is formed when the amount is 7% by weight or more. This is because the bleeding phenomenon of fluorinated pitch leaching on the surface of the sealing packing after molding occurs and causes an obstacle in the work of constructing the battery.

[0008]

EXAMPLE An example of the present invention will be described below with respect to a button type zinc-air battery.

FIG. 1 shows a vertical sectional view of a button type zinc-air battery. In FIG. 1, 1 is a negative electrode container made of a clad material in which a SUS material and a copper material having a thickness of 0.3 mm are laminated, 2 is a negative electrode mixture made of zinc powder, 3 is an insulating sealing packing made of 6.6 nylon, 4 Is a separator made of a microporous film, 5 is an air electrode containing manganese oxide as a main component, 6 is a water repellent film made of an unsintered fluororesin film,
Reference numeral 7 is an air diffusion paper, 8 is a positive electrode container in which the surface of an iron material having a thickness of 0.3 mm is plated with corrosion-resistant nickel, and 9 is an air hole. As the electrolytic solution, a 35% potassium hydroxide solution in which zinc oxide is dissolved is used.

PR44 (diameter: 11.4 mm, height: 5.4 mm) was constructed as a button-type zinc-air battery of the above construction, and an evaluation test was conducted on it.

As the sealing packing, first, 4 wt% of liquid fluorinated pitch having an atomic ratio F / C of carbon atoms (C) and fluorine atoms (F) of 2.0 was added to 6.6 nylon resin pellets. The mixture thus obtained is mixed and stirred for about 10 minutes while being heated to about 80 ° C., and a dry mixing operation of cooling to room temperature is performed to form a coating film of fluorinated pitch uniformly on the surface of the 6.6 nylon resin pellets. The thus treated product is filled in a hopper of a molding machine and molded into a predetermined shape to produce a sealing packing. The one in which this packing is fitted in the above-mentioned negative electrode container serves as a sealing body, and the one configured into a battery is referred to as a battery A. In addition, B is a product obtained by insert-molding the negative electrode metal container and the sealing packing, and is a battery C as a comparative example. In battery C, a sealant having a penetration of 20 was dissolved in toluene at a concentration of 30% by weight was used as a battery, and D was used. In the configuration of battery B, nothing was treated in the resin was E. Batteries A, B, C, D and E are manufactured and the temperature is 45 ° C and the humidity is 90%.
The number of leaked liquids after storage for 6 weeks and 9 weeks in the RH environment was examined. The number of samples was 100 in each case. Table 1 shows the results.
Shown in

[0012]

[Table 1]

As another embodiment, a cylindrical manganese dioxide using a fluorine-based lithium salt as an electrolyte in a mixed solvent of polyprene carbonate and dimethoxyethane as an electrolyte, manganese dioxide for the positive electrode, and metallic lithium for the negative electrode. Lithium battery, CR123A (diameter 17m
m, height 34 mm, electric capacity 1300 mAh), a battery made of polypropylene resin having the same fluorinated pitch compounding amount as the above A, F, and a battery G having the same configuration as the above B, comparison. The batteries C, D,
Each of 100 batteries H, I, and J having the same structure as E was prepared, and 1, 3, and 3 were placed in an atmosphere of a temperature of 60 ° C. and a relative humidity of 90%.
The number of leaked liquids when stored for 6 months was examined. The number of samples was 100 in each case. Table 2 shows the results.

[0014]

[Table 2]

As can be seen from (Table 1) and (Table 2), the batteries A, B and E, F using the fluorinated pitch of the present invention have sufficient leakage resistance.

As an example, a liquid fluorinated pitch having an atomic ratio F / C of carbon atoms (C) and fluorine atoms (F) of 2.0 was used, but carbon atoms (C) and fluorine atoms (F) were used. Similar results are obtained if the atomic ratio F / C of) is 1.8 to 2.3.

Such liquid fluorinated pitch is solid fluorinated pitch in a fluorine gas atmosphere at 0.5 to 1.5 ° C. /
It is obtained by raising the temperature to about 250 to 400 ° C. at a heating rate of a minute and reacting for about 10 hours.

[0018]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a liquid sealing material obtained by reacting fluorinated pitch with fluorine gas is used as a battery sealing packing interposed between a positive and negative metal container containing a power generating element. The fluorinated pitch is dry-mixed in a synthetic resin, and the mixture is molded into a predetermined shape by a molding machine, and the molded product is interposed as a sealing packing for a battery, whereby the leak-proof performance of the battery is remarkably improved. It is considered that this is because the chemical resistance and environment resistance of the fluorinated pitch with respect to the electrolytic solution are excellent, and the water repellency is extremely higher than that of the conventional sealing packing material.

[Brief description of the drawings]

FIG. 1 is a half-mounting sectional view of a button type zinc-air battery showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Negative electrode container 2 Negative electrode mixture 3 Insulating sealing packing 4 Separator 5 Air electrode 6 Water repellent film 7 Air diffusion paper 8 Positive electrode container 9 Air holes

Claims (3)

[Claims] 1. A method for producing a sealing packing for a battery, which is interposed between a positive and negative metal container containing a power generating element, the liquid fluorinated pitch obtained by reacting fluorinated pitch with fluorine gas. Is dry-mixed with a synthetic resin, and the mixture is molded into a predetermined shape by a molding machine. 2. A method of manufacturing a battery sealing packing, in which a positive / negative electrode metal container housing a power generating element and a sealing packing are integrally formed, and a peripheral edge of one of the positive / negative metal container. A method for producing a sealing packing for a battery, characterized in that a dry mixture of a liquid fluorinated pitch obtained by reacting a fluorinated pitch with a fluorine gas is mixed in a synthetic resin into a predetermined shape by a molding machine. . 3. The sealing packing for a battery according to claim 1, wherein the atomic ratio F / C of carbon atoms (C) to fluorine atoms (F) of the liquid fluorinated pitch is 1.8 to 2.3. Manufacturing method.