JP2000048780A - Coin-shaped organic electrolyte battery and method of manufacturing the same - Google Patents

Abstract

(57) [Summary] [Problem] To accommodate a positive electrode, a negative electrode using lithium as an active material, and a power generation element including an organic electrolyte in a positive electrode case also serving as a positive electrode terminal, and to open the positive electrode case with a sealing plate also serving as a negative electrode terminal. When a coin-shaped organic electrolyte battery whose part is sealed via a gasket is used for a long period of time, a difference is generated between the inside of the battery container and the atmospheric pressure due to gas generation in the battery container, and the caulked seal There is a possibility that a phenomenon in which the electrolytic solution leaks from the inside of the battery container in a state where the pressure is higher than the atmospheric pressure to the outside in a portion where the above-described process is performed, that is, a so-called liquid leak may occur. SOLUTION: The sealing plate has a folded portion which is folded in a U-shape with the outer peripheral portion facing the positive electrode case side, and a flat portion following the folded portion, and the width of the flat portion is larger than the plate thickness. 75 to 15
Preferably, the angle formed between the surface facing the inner surface of the battery case in contact with the flat portion and the perpendicular to the top surface of the sealing plate is in the range of 5 to 15 °.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery container comprising a positive electrode case also serving as a positive electrode terminal and a sealing plate also serving as a negative electrode terminal, in which a power generating element is housed, and a sealing plate and a gasket are arranged at an opening of the positive electrode case. TECHNICAL FIELD The present invention relates to a coin-shaped organic electrolyte battery having a swaged-sealed structure and improved leakage resistance at the swaged-sealed portion.

[0002]

2. Description of the Related Art In general, an organic electrolyte battery using lithium or an alloy thereof for a negative electrode has a high energy density because lithium is used as an active material. For this reason, not only can the device be reduced in size and weight, but also because it has high reliability, it is used as a main power source and a memory backup power source for various electronic devices. In recent years, with the development of rechargeable secondary batteries,
Its demand is increasing year by year. In particular, a coin-shaped organic electrolyte battery is used as a main power supply or a memory backup power supply for small precision equipment, and it is necessary to ensure high reliability over a long period of time.

[0003]

When a coin-shaped organic electrolyte battery is used for a long period of time, a small amount of gas is generated in the battery container. Due to the generation of this gas, the internal pressure of the battery container increases. At this time, there is a difference between the inside of the battery container and the atmospheric pressure, and there is a possibility that liquid leakage will occur from the portion where the swaging is performed due to the pump-up effect. In particular, in the case of a secondary battery, the gas generation rate increases due to repeated charging and discharging. As a result, the circuit around the battery is damaged,
Equipment failure. An object of the present invention is to ensure particularly high leakage resistance.

[0004]

In order to solve these problems, a coin-shaped organic electrolyte battery according to the present invention comprises a positive electrode,
A power generating element composed of a negative electrode using lithium as an active material and an organic electrolyte is accommodated in a positive electrode case also serving as a positive electrode terminal, and the outer peripheral portion is folded in a U-shape toward the positive electrode case, and a flat portion is formed in the folded portion. A coin-shaped organic electrolyte battery in which the opening of the positive electrode case is sealed via a gasket by a sealing plate also serving as a negative electrode terminal, wherein the flat portion has a width of 75 to 150 with respect to the plate thickness of the sealing plate. %.

[0005] Further, when the positive electrode case is curled inward by the sealing die and the upper holding pin and the lower holding pin to perform the sealing process, the inner diameter of the hole into which the upper holding pin is inserted is reduced. The sealing process is performed using a sealing die that is smaller than the upper end opening diameter of the positive electrode case and holds the upper portion of the gasket by 80% or more.

When the positive electrode case and the sealing plate are caulked and closed via a gasket, the positive electrode case is folded between the positive electrode case opening and the sealing plate, between the positive electrode case and the peripheral edge of the sealing plate, and between the positive electrode case and the sealing plate. The gasket interposed between the parts has a compression ratio of 30 to 70%.

As a result, the leakage resistance of the coin-type organic electrolyte battery is improved.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION According to the first aspect of the present invention, a positive electrode, a negative electrode using lithium as an active material, and an organic electrolyte are housed in a battery container comprising a positive electrode case and a sealing plate, and a gasket is provided. A coin-shaped organic electrolyte battery having a structure that is sealed by caulking with a plate having a thickness of 7 mm at a folded portion as the sealing plate.
A coin-shaped organic electrolyte battery characterized by having a flat portion of 5 to 150%, wherein stress applied to a gasket at the bottom of the battery at the time of sealing is dispersed to prevent gasket deterioration while preventing gasket deterioration. The sealing plate and the case are sufficiently adhered.

According to a second aspect of the present invention, as the sealing plate, an angle θ formed by a perpendicular line between the folded outermost edge and the top of the sealing plate.
Is a coin-shaped organic electrolyte battery according to claim 1, wherein
Prevents deformation of the inside of the folded part of the sealing plate when sealing,
Applying a force in the direction of the opening of the sealing plate improves the adhesion between the gasket, the sealing plate, and the case.

According to a third aspect of the present invention, the thickness of the positive electrode case is 65 to 85% of the thickness of the sealing plate, and the inside of the case opening end is cut at an angle of 80 to 100 °. 3. The coin-shaped organic electrolyte battery according to claim 1, wherein the thickness of the case is 65 to 85% of the thickness of the sealing plate when the battery is sealed. Prevents internal deformation. Further, by using a sealing plate having a flat portion with a thickness of 75 to 150% in the folded portion as a sealing portion, stress applied to the gasket at the bottom of the battery at the time of sealing can be dispersed to prevent the gasket from deteriorating. By using a material whose inside of the open end is cut at an angle of 80 to 100 ° to prevent movement due to penetration into the gasket at the time of sealing, the gasket is sufficiently adhered to the sealing plate and the case. It is a thing.

According to a fourth aspect of the present invention, a positive electrode, a negative electrode using lithium as an active material, and an organic electrolytic solution are housed in a battery container including a positive electrode case and a sealing plate, and are sealed with a gasket. A coin-shaped organic electrolyte battery,
When the organic electrolyte lithium battery is subjected to a sealing process by curling the positive electrode case inward with a sealing mold and an upper holding pin and a lower holding pin and performing the sealing process, an inner diameter of a hole into which the upper holding pin enters is curled inward. A coin-shaped organic electrolyte battery characterized by being sealed using a mold that is smaller than the upper end opening diameter of the positive electrode case of the battery and holds the upper portion of the gasket by 80% or more, and the gasket moves at the time of sealing. And the gasket is present without any gap between the sealing plate and the case, whereby sufficient adhesion can be obtained.

The invention according to claim 5 is characterized in that when the positive electrode case and the sealing plate are swaged and closed via a gasket,
The coin shape according to claim 4, wherein the compression ratio of the gasket interposed between the opening of the positive electrode case and the sealing plate, between the positive electrode case and the peripheral edge of the sealing plate, and between the positive electrode case and the folded back of the sealing plate is 30 to 70%. It is an organic electrolyte battery, and by sealing in a well-balanced manner, the movement of the gasket is prevented, and the adhesion between the gasket, the sealing plate, and the case is improved.

According to a sixth aspect of the present invention, a flat portion having a thickness of 75 to 150% is provided in the folded portion as the sealing plate, and the angle formed by the perpendicular line between the folded outermost edge and the top of the sealing plate is 5 to 15 degrees.
5.The coin-shaped organic electrolyte battery according to claim 4, wherein a gasket at the bottom of the battery at the time of sealing is prevented. The gasket is sufficiently adhered to the sealing plate and the case while dispersing such stress and preventing deterioration of the gasket. Furthermore, at the time of sealing, the inside of the folded portion of the sealing plate is prevented from being deformed, a force is applied in the direction of the opening of the sealing plate, and the gasket is moved between the sealing plate and the case by preventing movement of the gasket. It is present without any gaps and improves the adhesion between the gasket, the sealing plate and the case.

According to a seventh aspect of the present invention, the thickness of the positive electrode case is 65 to 8 times the thickness of the sealing plate.
5%, and the inside of the case opening end is cut at an angle of 80 to 100 [deg.], Wherein the coin-shaped organic electrolyte battery according to claim 5 or 6, By setting the thickness of the case to 65 to 85% of the thickness of the sealing plate, deformation of the folded portion of the sealing plate into the inside is prevented. Further, a thickness of 75 to 150
%, The stress applied to the gasket at the bottom of the battery at the time of sealing can be dispersed, and deterioration of the gasket can be prevented. In addition, by using a case in which the inside of the case opening end is cut at an angle of 80 to 100 °, the positive electrode case is inserted into the gasket at the time of sealing, and at the same time, movement is prevented by pressing the gasket with the sealing mold. from these things,
The gasket exists without any gap between the sealing plate and the case, and sufficient adhesion can be obtained.

By adopting the constitution of the present invention as described above, the adhesion between the case and the sealing plate and the gasket is improved, and the leakage resistance of the coin-type organic electrolyte battery in which charging and discharging are repeated with generation of gas is performed. The characteristics can be improved.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a partial cross-sectional view of a coin-shaped organic electrolyte battery and a cross-sectional view showing the state of a sealing die, an upper holding pin, and a lower holding pin used for sealing. In FIG. 1, reference numeral 1 denotes a sealing plate, which is made of stainless steel. The sealing plate 1 has a folded portion 1a that is folded toward the outer periphery of the sealing plate. The width W of the folded portion 1a is 75 to 1
A flat portion of 50% is provided, and the angle θ formed by the perpendicular line between the folded outermost edge and the top is 5 to 15 °. Reference numeral 2 denotes a case, which is made of stainless steel. The thickness is 6 times the thickness of the sealing plate.
5 to 85%, and the inside of the case opening end is 80 to 100%.
It was cut at an angle of °. 3 uses a polypropylene gasket and compresses the gasket interposed between the opening of the positive electrode case and the sealing plate, between the positive electrode case and the peripheral edge of the sealing plate, and between the positive electrode case and the folded back of the sealing plate when swaged. The rate is 30-70%. Reference numeral 4 denotes a positive electrode in which 90% by weight of lithium manganese oxide, 5% by weight of acetylene black as a conductive material, and 5% by weight of a fluororesin as a binder were kneaded so as to have a weight ratio of 5% by weight.
Pellets are molded to a size of 0.8 mm in thickness.
Reference numeral 5 denotes a negative electrode in which 90% by weight of lithium titanium oxide, 5% by weight of acetylene black as a conductive material, and 5% by weight of a fluororesin as a binder are kneaded so as to have a weight ratio of 15 mm and a thickness of 0.5 mm. Pellet molding is performed. Reference numeral 6 denotes a polypropylene nonwoven cloth having a thickness of 0.3 mm. The electrolyte used was one in which LiClO ₄ was dissolved at a ratio of 1 mol / l in a solvent in which PC and DME were mixed at a volume ratio of 1: 1. Reference numeral 7 denotes a sealing die, 8 denotes an upper holding pin, and 9 denotes a lower holding pin. When the positive electrode case is curled inward and the sealing process is performed, the inner diameter of the hole into which the upper holding pin enters is curled inward. Of the gasket is smaller than the opening diameter of the upper end of the positive electrode case of the battery.
%. This battery of the present invention is designated as A.

For comparison, B is a battery having no flat portion at the folded portion of the sealing plate. Also, the battery in which the angle θ formed by the perpendicular line between the folded outermost edge and the top is 0 ° is C. further,
As a case, the battery whose thickness is the same as the thickness of the sealing plate, and whose inside of the case opening end is an arc is D. Similarly, a battery in which the case thickness is 50% of the thickness of the sealing plate and the inside of the case opening end is an arc is E. Next, as a sealing mold, a battery that has been sealed using a mold in which the inner diameter of the hole into which the upper holding pin enters is the same as the upper end opening diameter of the positive electrode case of the battery that has been curled inward is F, Gasket top 5
G is a battery that has been sealed using a mold that holds 0%. Further, when the positive electrode case and the sealing plate are swaged and closed via a gasket, the gap between the positive electrode case opening and the sealing plate, between the positive electrode case and the peripheral edge of the sealing plate, and between the positive electrode case and the folded portion of the sealing plate. The battery in which the compression ratio of the gasket interposed therebetween is 10 to 20% is denoted by H, and similarly, the compression ratio is 80 to 9%.
The battery which is 0% is denoted by I. Other configurations are exactly the same as the battery A. Each of these batteries is composed of 100 pieces,
The result of the leak rate in the leak test in which 300 cycles are repeated, where the thermal shock cycle in which the temperature is maintained at 60 ° C. for 1 hour and then the temperature is maintained at −10 ° C. for 1 hour, is shown as one cycle.

[0019]

[Table 1]

In the battery B, since there was no flat portion in the folded portion of the sealing plate, stress was applied to one point of the gasket, and the gasket was deformed and cracked. In the battery C, since θ was 0 °, deformation of the folded portion of the sealing plate toward the inside of the battery due to the stress applied to the side of the sealing plate at the time of sealing was observed.
In the case of the battery D, the thickness of the case is the same as the thickness of the sealing plate. Therefore, when the battery is sealed, the folded portion of the sealing plate is deformed to the inside of the battery due to the stress applied to the side of the sealing plate as in the case of the battery B. did. Further, since the inside of the case opening end was a circular arc, the gasket slipped, and the battery protruded outward. As a result, the volume of the gasket between the case and the sealing plate is reduced, and the adhesion between the gasket and the case and the sealing plate is reduced, so that it is considered that the liquid leakage resistance is low. In the battery E, the case thickness is 5 times the thickness of the sealing plate.
Since it is 0%, the strength of the case at the time of sealing is low, so that the case cannot be sufficiently caulked, and since the inside of the case opening end is an arc, the gasket slips like the battery D and does not protrude to the outside of the battery. there were. From these facts, it is considered that the gasket moves during the temperature change, and the adhesion between the gasket and the sealing plate decreases, so that the liquid leakage resistance is low. Battery F was sealed using a mold in which the inner diameter of the hole into which the upper holding pin was inserted was the same as the opening diameter of the upper end of the positive electrode case of the battery curled inward. It could not be held down sufficiently, and the battery ran out of the battery, and, like Battery D, is considered to have low leakage resistance. Battery F can be considered in the same manner as battery E. In the battery H, when the positive electrode case and the sealing plate were swaged and closed via a gasket, the space between the positive electrode case opening and the sealing plate, the positive electrode case and the peripheral edge of the sealing plate, and the positive electrode case and the sealing plate When the temperature changes due to insufficient compression rate of the gasket interposed between the folded parts,
Since the gasket moves between the positive electrode case and the sealing plate without being sufficiently adhered, the leakage resistance is low. Conversely, battery I
When the compression ratio becomes 80 to 90%, the gasket loses elasticity, and the gasket moves between the positive electrode case and the sealing plate with a change in the internal pressure of the battery due to a temperature change. Can be

[0021]

As described above, by employing the structure of the present invention, the gasket is prevented from protruding, moving, and deforming to the outside of the battery at the time of sealing, and the adhesion between the gasket, the case, and the sealing plate is improved. In addition, the leakage resistance of the coin-type organic electrolyte battery can be remarkably improved. of course,
The present invention can be applied to not only a primary battery but also a coin-type chargeable / dischargeable lithium secondary battery.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a coin-type organic electrolyte battery in a sealing step.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sealing plate 2 Positive electrode case 3 Gasket 4 Positive electrode 5 Negative electrode 6 Separator 7 Sealing mold 8 Upper holding pin 9 Lower holding pin

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H011 AA17 CC06 DD06 DD15 DD26 GG02 HH02 JJ12 KK01 KK02 KK03 5H024 AA02 BB00 BB05 BB14 BB20 CC03 DD01 DD04 FF11 FF36 HH01 HH13

Claims (7)

[Claims] 1. A power generating element comprising a positive electrode, a negative electrode using lithium as an active material, and an organic electrolyte is accommodated in a positive electrode case also serving as a positive electrode terminal, and an opening of the positive electrode case is sealed with a gasket by a sealing plate also serving as a negative electrode terminal. Wherein the sealing plate has a folded portion folded in a U-shape with an outer peripheral portion facing the positive electrode case side, and a flat portion following the folded portion. Having a width of 75 to 15 with respect to the thickness of the sealing plate.
A coin-shaped organic electrolyte battery characterized by being in the range of 0%. 2. An angle formed between a surface in contact with the flat portion and facing the inside of the battery case and a perpendicular to a top surface of the sealing plate is 5 to 15 °.
2. The coin-shaped organic electrolyte battery according to claim 1, wherein a sealing plate in the range of ° is used. 3. The thickness of the positive electrode case is in the range of 65 to 85% with respect to the thickness of the sealing plate, and the angle of the end face of the case opening with respect to the inner surface of the battery case is in the range of 80 to 100 °. 3. The coin-shaped organic electrolyte battery according to claim 1 or 2. 4. A power generating element comprising a positive electrode, a negative electrode using lithium as an active material, and an organic electrolyte is housed in a battery container in which a positive electrode case and a sealing plate are disposed via a gasket, and a sealing mold and an upper holding pin are provided. And a lower holding pin to curl the positive electrode case inward, and a method of manufacturing a coin-type organic electrolyte battery having a sealing step of sealing the battery container, wherein the sealing mold moves the gasket in the height direction. And a hole through which the upper holding pin penetrates, the inner diameter of the hole is smaller than the diameter of the upper end opening of the positive electrode case, and the upper portion of the gasket is
A method for producing a coin-shaped organic electrolyte battery, wherein a sealing process is performed using a mold that holds 0% or more. 5. In the sealing step, a U-shape is formed so that the space between the positive electrode case opening and the sealing plate, the space between the positive electrode case and the peripheral edge of the sealing plate, and the outer peripheral portions of the positive electrode case and the sealing plate face the positive electrode case. 5. The method for producing a coin-shaped organic electrolyte battery according to claim 4, wherein the compression ratio of the gasket interposed between the folded portions is in the range of 30 to 70%. 6. A folded portion having an outer peripheral edge folded toward the positive electrode case in a U-shape, and a flat portion following the folded portion, the width of the flat portion being the thickness of the sealing plate. 75 to 15 for
The angle between the surface which is in the range of 0% and which is in contact with the flat portion and which faces the inside of the battery case and the perpendicular to the top surface of the sealing plate is 5 °.
5. The method for producing a coin-type organic electrolyte battery according to claim 4, wherein a sealing plate having a range of about 15 [deg.] Is used. 7. The thickness of the sealing plate is 65 to 8 with respect to the thickness of the sealing plate.
5. The method for manufacturing a coin-type organic electrolyte battery according to claim 4, wherein the positive electrode case has a range of 5% and an angle of an end face of the case opening with respect to an inner surface of the battery case is in a range of 80 to 100 [deg.].