JPS6136344B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention uses active light metals such as lithium, magnesium, and potassium as negative electrode active materials, and uses graphite fluoride,
A positive electrode active material consisting of manganese dioxide, copper oxide, etc.
The purpose of this invention is to significantly improve the leakage resistance and storage performance of non-aqueous electrolyte batteries using non-aqueous electrolytes. Conventionally, batteries of this type have had the disadvantage that the rate of leakage increases as the number of days after storage passes, self-discharge progresses, and the capacity after storage decreases considerably. These defects are overwhelmingly due to imperfections in the sealing structure, and these defects can be almost eliminated if the battery is completely sealed, regardless of whether the battery is flat, cylindrical, or thin. Various attempts have been made to completely seal batteries, but the above-mentioned drawbacks have not been completely eliminated. As an example, a flat non-aqueous electrolyte battery will be described. Conventional batteries have a structure as shown in Figures 1 and 2, and for the purpose of complete sealing, the case 2 is bent using a sealing mold as shown in Figure 2, and a synthetic resin insulator is inserted into the battery. Parts a and b of the sealing ring 3 are deformed and compressed by 20 to 50%, and the sealing plate 1 is
It had a structure in which a sealing ring was inserted between the case 2 and case 2. Furthermore, for the purpose of complete sealing, a polymeric sealant 9 such as polybdenum or polyisobutylene is coated or filled on the opposing portion 7 of the sealing ring and the anode case and the opposing portion 7' of the sealing ring and the cathode sealing plate. Ta. However, in this type of battery, a solution of propylene carbonate, dimethoxyethane, γ-butyrolactone, etc. alone or as a mixture, and lithium borofluoride or lithium perchlorate dissolved therein is generally used as the electrolyte 8. Since these are all volatile organic solvents, the above-mentioned sealing materials have the disadvantage of gradually dissolving in the solvent, swelling and softening during storage after battery manufacture, and as a result, after long-term storage, the electrolyte solution 7 and 7' which are the seal parts
The leakage resistance was extremely poor. Furthermore, the dissolution/swelling/softening phenomenon of the sealing material becomes more pronounced as it is stored at higher temperatures, resulting in general leakage in flat batteries during storage at 45°C, storage at 60°C, and high/low temperature cycle tests. In the test method, there were drawbacks in that the sealing material was pushed out of the battery and the leakage resistance was significantly deteriorated. The present invention aims to improve the above-mentioned drawbacks, and one embodiment of the present invention will be described below with reference to the drawings. In FIG. 1 and FIG. 2 showing an enlarged view of part A thereof, reference numeral 1 denotes a sealing plate to which a negative electrode lithium 5 is crimped; inside the sealing plate, a separator 6 made of polypropylene, graphite fluoride, manganese dioxide, A molded positive electrode mixture 4 containing copper or the like as a positive electrode active material is placed, a nonaqueous electrolyte 8 containing propylene carbonate and dimethoxyethane as main components is sealed, and a portion 7 where the sealing ring 3 and the positive electrode case 2 face each other is formed. A flexible and adhesive sealant 9a made of, for example, a mixture of pitch and non-drying mineral oil is interposed tightly between the portion 7' where the sealing ring 3 and the sealing plate 1 face each other, and the negative electrode sealing plate 1 A sealing ring 3 is inserted between the positive electrode case 2 and the positive electrode case 2 to make a complete seal. The mixture of pitch and non-drying mineral oil or non-drying vegetable oil according to the present invention can satisfy all of the following conditions for a sealant by adjusting the blending ratio appropriately. Do not dissolve, swell, or soften in organic electrolyte during battery storage. At a temperature that prevents the synthetic resin insulating sealing ring 3 from melting, softening, or deforming,
Portion 7 where the sealing ring 3 and the positive electrode case 2 face each other
Also, the portion 7' where the sealing ring 3 and the negative electrode sealing plate 1 face each other can be coated or filled without any gaps.
The purpose is to firmly and liquid-tightly adhere to all of the sealing ring 3, positive electrode case 2, and negative electrode sealing plate 1. The non-drying mineral oil or non-drying vegetable oil that is mixed into the pitch is intended to give flexibility and strong adhesion to the pitch, and therefore, considering its effects, it should volatilize and lose weight even after long-term storage. It must not be. The pitch-based sealant in which non-drying mineral oil or non-drying vegetable oil is mixed in an amount of 6 to 18% by weight of the total weight of the sealant according to the present invention is based on polymers such as polybutene and polyisobutylene that have been conventionally used as sealants. Compared to compounds, it is extremely difficult to dissolve and does not swell even when it comes into contact with organic electrolytes used in non-aqueous electrolyte batteries. In addition, even at high temperatures of 45°C to 60°C, it has less fluidity than polybutene or polyisobutylene, and has excellent adhesion to metals and resins, so it does not leak out of the battery and is extremely durable. Shows excellent leakage resistance. Figure 3 shows pitch (brown asphalt) made by mixing non-drying mineral oil (process oil used as a plasticizer or softener for rubber or printing ink) and non-drying vegetable oil (soybean oil) in various proportions.
The results of a leakage test are shown for a flat battery whose sealant is filled with a main sealant. Each battery has an outer diameter of 23.0 mm and a total height of 2.0 mm, and there are 200 samples for each battery. Leakage rate after 100 days of storage, (b) is 100 at 45°C for a battery with the same encapsulant as in (a).
Leakage rate after 1 day storage, (c) at high temperature (60
After conducting a cycle test (MIL.STD 202D-106C) that repeats storage at low temperature (-10°C) and low temperature (-10°C) for 10 days, the leakage rate after being left at room temperature for 90 days, (d) is (a) 100 at 60°C with the same encapsulant as
(a)′ is the leakage rate after 100 days of storage at room temperature for a battery equipped with a pitch-based sealant mixed with non-drying vegetable oil, (b)′ is (a)′ at 45 °C for cells with the same encapsulant as
Leakage rate after 100 days of storage, (c)′ is the high temperature (60
℃) and low temperature (-10℃) cycle test. (d)′ at 60°C for a battery with the same encapsulant as (a)′.
The leakage rate after 100 days of storage is shown. In various leakage tests (RT, 45℃, 60℃, heat cycle), all results show that the amount of non-drying mineral oil and non-drying vegetable oil mixed is 6 to 18% by weight of the total amount of sealant.
In the case of , the range of 6 to 18% by weight is considered good because the leakage rate is low compared to other mixing amounts, and this is clear from Figure 3. . This is due to the lack of flexibility as a sealant in the area where the blending ratio of pitch alone or non-drying mineral oil or non-drying vegetable oil is less than 6% by weight, and it also has poor flexibility as a sealing agent for sealing rings, battery cases, and sealing plates. Because the adhesion to each of these is weak and easy to peel off,
It is thought that the electrolyte easily leaked from between the sealing plate and the sealing ring and between the battery case and the sealing ring, resulting in a high leakage rate. On the other hand, if the mixing ratio of non-drying mineral oil or non-drying vegetable oil is greater than 18% by weight, the sealant will have good flexibility and adhesion to metals, etc., but on the other hand, it will become fluid at high temperatures. Therefore, if stored at high temperatures such as 45°C or 60°C, this sealant will easily soften, flow, and flow out of the battery, and will no longer function as a sealant, resulting in battery leakage. It is thought that the rate will be very high. In addition, the effect as a sealant when non-drying mineral oil and non-drying vegetable oil are used as a mixture is that, in the range of 6 to 18% by weight, non-drying is achieved in both blending ratios. Better results were obtained using mineral oil. This is because non-drying mineral oil is chemically more stable and less susceptible to deterioration, and in the case of the same blending ratio, it has the same adhesion and flexibility at room temperature as non-drying vegetable oil. This is thought to be because it has little fluidity at high temperatures such as °C and is difficult to leak out of the battery. A few examples of mixtures having the above properties will be described below. (a) Bronze Asphalt 10-20 (penetration 10-20m/m at temperature 25℃, test method is
According to JIS-K-2207), 90 parts by weight of mineral oil, which is a fractionated residue of petroleum (process oil used as a plasticizer or softener for rubber or printing ink), is added to A mixture of 10 parts by weight (manufactured by Sekiyu Co., Ltd.) uniformly dissolved and mixed was used as a sealant. When actually applying or filling this sealant to a predetermined area, the temperature is 60°C at which the synthetic resin sealing ring 3 does not soften.
It is necessary to apply or fill the sealant at a temperature below ℃, and in order to increase the fluidity of the sealant, 1 part by weight of the above mixture is uniformly dissolved and mixed in 2 parts by weight of an organic solvent, such as toluene or a mixture of toluene and petroleum benzine. After coating or filling, only the organic solvent was evaporated and dried. (b) As a pitch, 10 parts by weight of soybean oil is uniformly dissolved and mixed with 90 parts by weight of Bron Asphalt 20-30 (penetration 20-30 m/m at a temperature of 25°C). After uniformly dissolving and mixing 1 part by weight of this mixture with 2 parts by weight of the organic solvent, the mixture is applied or filled onto a predetermined area, and then only the organic solvent is evaporated.
Dry. If the above-mentioned filling is filled without any gaps in the portion 7 where the synthetic resin sealing ring 3 and the battery case face each other, and the portion 7' where the sealing ring 3 and the sealing plate 1 face each other, this filling will be Since the sealing ring 3, the battery case 2, and the sealing plate 1 have extremely good adhesion and are not dissolved in the electrolyte, the airtightness of the sealing portion is sufficiently maintained. Therefore, the leakage resistance of the battery is greatly improved, and since the electrolyte does not dissipate during storage, the storage performance is also greatly improved. Next, after storage of the flat non-aqueous electrolyte battery A with a sealed structure using the sealant of the present invention shown in (a) above, and the same type battery B using the conventional polyisobutylene as the sealant, Tables 1 and 2 show a comparison of discharge performance and leakage resistance performance. Both batteries A and B had an outer diameter of 23.0 m/m and a total height of 2.0 m/m. However, the discharge performance is shown as the cumulative average discharge duration until the voltage drops to 2.4V when continuous discharge is performed at a temperature of 20°C with a load of 30KΩ connected. Regarding leakage resistance, the number of leaking batteries after being left at 45℃ for 100 days, the number of leaking batteries after being left at 60℃ for 100 days, and the high temperature (60℃) and low temperature (-10℃) cycle test (MIL) .STD 202D-106C) for 10 days and after being left at room temperature for 90 days, the number of leaking batteries is shown.

【table】

[Table] As is clear from the above examples, the present invention provides a flat nonaqueous electrolyte battery in which a synthetic resin sealing ring and a battery case face each other, and a sealing ring and a sealing plate face each other in a part where a synthetic resin sealing ring and a battery case face each other. The sealant is mainly composed of pitch and contains a sealant mixed with non-drying mineral oil or non-drying vegetable oil in an amount of 6 to 18% by weight of the total amount of the sealant. Therefore, the airtightness of the battery was maintained well, and leakage of the electrolyte solution was prevented, and the storage performance and leakage resistance performance were greatly improved. Note that the use of such a sealant is applicable not only to flat batteries, but also to the sealing parts of cylindrical non-aqueous electrolyte batteries shown in Figure 4 and narrow non-aqueous electrolyte batteries shown in Figure 5. be able to. In the cylindrical battery shown in FIG. 4, there is a space between the battery case 1a, which also serves as a negative electrode terminal, and a disc-shaped resin sealing plate 3a, and an aluminum rivet 2a, which is the internal terminal of the positive electrode, which is caulked to this sealing plate. A sealing agent 9a is interposed between the two, and a positive electrode terminal 2b is fixed onto the caulking stud 2a. In addition, in the narrow battery shown in FIG. 5, there is a negative electrode current collector rod 1' between the elongated cylindrical battery case 2 which also serves as a positive electrode terminal and a sleeve-shaped insulating sealing body 3b made of synthetic rubber, and which forms a negative electrode terminal with this sealing body. A sealant 9a is interposed between the two. The third comparison of leakage resistance performance when using the sealant of the present invention for cylindrical and narrow non-aqueous electrolyte batteries
Shown in the table. Table 3 shows a cylindrical, narrow non-aqueous electrolyte battery A whose sealing part was filled with the sealant A of the present invention used in the flat battery example, and a conventional polyisobutylene used as a sealant. The number of leakage batteries after being left at 45°C for 100 days and at 60°C for 100 days is shown for the same type of battery B. The cylindrical non-aqueous electrolyte batteries A and B both have an outer diameter of 17.0 mm and a total battery height of 33.5 mm.The narrow non-aqueous electrolyte batteries have an outer diameter of 3.5 mm and a total height of 40.0 mm for both A and B.
mm, and each sample was 200 pieces.

[Table] Even with these structures, excellent leakage resistance and storage performance can be obtained, similar to the flat battery described above.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a flat non-aqueous electrolyte battery according to an embodiment of the present invention, FIG. 2 is an enlarged sectional view of part A in FIG. 1, and FIG. 3 is a mineral oil or vegetable oil for sealant pitch. FIG. 4 is a half-cut side view of a cylindrical non-aqueous electrolyte battery according to another embodiment of the present invention, and FIG. 5 is a diagram showing the relationship between the compounding ratio of It is a half-cut side view of an electrolyte battery. 1...Sealing plate that also serves as a negative electrode terminal, 1a...Battery case that also serves as a negative electrode terminal, 1'......Battery case that also serves as a negative electrode terminal, 2...Battery case that also serves as a positive electrode terminal, 2a
... Caulking stud, 2b ... Positive electrode terminal, 3 ... Insulating sealing ring, 3a ... Sealing plate, 3b ... Sleeve-shaped sealing body, 4 ... Positive electrode mixture, 5 ... Negative electrode, 6 ... Separator, 8 ...Nonaqueous electrolyte, 9a...Sealant.

Claims (1)

[Scope of Claims] 1. Between the positive and negative metal terminals and an insulating sealing body made of synthetic resin or synthetic rubber, a sealant containing pitch as a main component and 6 to 18% by weight of the total weight of the sealant is used. A non-aqueous electrolyte battery characterized by interposing a sealant containing a mixture of non-drying mineral oil or non-drying vegetable oil. 2. The sealant is interposed between the battery case and the insulating sealing ring, which also serves as a terminal for one of the positive or negative poles, and between the sealing plate, which also serves as the terminal for the other pole, and the insulating sealing ring. A non-aqueous electrolytic battery according to claim 1. 3. The sealant is applied between the battery case and the insulating sealing plate, which also serves as a terminal for one of the positive and negative poles, and between the insulating sealing plate and the caulking stud, which is the other terminal terminal, which is caulked thereto. A nonaqueous electrolyte battery according to claim 1 of the intervening claims. 4. The sealant is applied between the battery case and the sleeve-shaped insulating sealing body, which also serves as a terminal for one of the positive and negative poles, and between the current collector rod, which also serves as the other terminal, and the sleeve-shaped insulator. The non-aqueous electrolyte battery according to claim 1, wherein each of the non-aqueous electrolyte batteries is interposed.