JP2003037028A - Capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a capacitor capable of keeping stability of electrical characteristics over a long term. SOLUTION: A capacitor element 1 is arranged inside an outer case 2 formed by sealing laminated films in which a metal foil and a plastic film are superposed. An outgassing valve 5 having an oil seal structure is attached on an inside wall of the outer case 2, and a pin hole 4 for outgassing from the outgassing valve 5 to the outside is further formed in the outer case 2. Thereby, the gas generated inside the outer case 2 is outgassed from the pin hole 4 to the outside via the outgassing valve 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor having a gas releasing mechanism.

[0002]

2. Description of the Related Art In recent years, secondary batteries, electric double layer capacitors, and the like have been developed in which a laminated film formed by laminating a metal foil such as aluminum and a plastic film is used as an outer case. These generally contain an electrolytic solution inside, and the inside of the outer case is configured to be in a hermetically sealed state in order to prevent deterioration due to intrusion of moisture, oxygen, or the like from the outside. . Here, the electric double layer capacitor is, for example,
Electrode solution is applied to an electrode laminate in which a plurality of positive electrodes and a plurality of negative electrodes are alternately laminated with a separator interposed therebetween, or a wound body formed by winding a set of positive and negative electrodes with a separator interposed therebetween. It is configured so as to be stored in an outer case in an impregnated state.

[0003]

By the way, the electric double layer capacitor and the secondary battery as shown above have a structure in which the electrolytic solution in the outer case causes electrolysis when they are used for a long period of time. Decomposition gas (for example, carbon monoxide or carbon dioxide) may be generated inside the case. At this time, the outer case formed of the above-mentioned laminated film has a high responsiveness to the internal pressure, so that the outer case swells even if a small amount of gas is generated. Further, since the laminated film has a low breakdown voltage, there is a high possibility that the expansion will cause the outer case to lose its airtightness, resulting in low reliability in long-term use.

The present invention has been made to solve the above-mentioned conventional drawbacks, and an object thereof is to provide a capacitor capable of improving the stability of electrical characteristics for a long period of time. It is also an object of the present invention to improve safety when overloaded.

[0005]

Therefore, the capacitor according to the first aspect is a capacitor having an outer case 2 formed of a material in which a metal foil and a plastic film are superposed, and an oil seal structure is provided inside the outer case 2. While attaching the gas release valve 5, the outer case 2 is
It is characterized in that a pinhole 4 is formed to release gas from the gas release valve 5 to the outside.

According to the capacitor of the first aspect, the gas generated inside the outer case 2 can be released to the outside from the pinhole 4 through the gas release valve 5, so that the outer case 2 swells. It is possible to prevent the seal from being damaged.

The capacitor according to a second aspect of the invention is characterized in that the gas release valve 5 is covered with a selective gas permeable material 11 that selectively permeates an internally generated gas.

According to the capacitor of the second aspect, the gas release valve 5 is constructed so as to be covered with the selective gas permeable material 11 which transmits the internally generated gas. As a result, it is possible to release the gas (for example, carbon monoxide or carbon dioxide) generated inside the outer case 2 to the outside, while blocking oxygen, water, or the like entering from the outside. Further, by providing the selective gas permeable material 11, it is possible to prevent the electrolytic solution existing in the outer case 2 from leaking to the outside together with the gas release. As a result, it is possible to prevent the airtightness from being damaged due to the bulging of the outer case 2, and to improve the stability of electrical characteristics for a long period of time.

Further, the capacitor according to claim 3 is a capacitor having an outer case 2 formed by sealing a material obtained by stacking a metal foil and a plastic film, and the cap member 14 is sandwiched between the sealing portions 13. However, the opening 15 of the plug member 14 is closed by a selective gas permeable material 11 that selectively permeates an internally generated gas.

According to the capacitor of the third aspect, since the opening 15 of the plug member 14 sandwiched by the seal portion 13 is closed by the selective gas permeable material 11, the inside of the outer case 2 is covered. It is possible to release the generated gas (for example, carbon monoxide or carbon dioxide) to the outside, while blocking oxygen, water, or the like entering from the outside. By providing this selective gas permeable material 11,
It is also possible to prevent the electrolytic solution existing in the outer case 2 from leaking to the outside when the gas is released. As a result, with a simple structure, it is possible to prevent the breakage of the seal due to the bulging of the outer case 2 and improve the stability of the electrical characteristics for a long period of time.

The capacitor according to claim 4 is a capacitor having an outer case 2 formed by sealing a material in which a metal foil and a plastic film are laminated, and a cap member 14 is sandwiched between the sealing portions 13. Then, the opening 15 of the plug member 14 is closed by the plug 18, and when the internal pressure of the outer case 2 rises, the plug 18 is removed to release the internally generated gas to the outside of the outer case 2. It is characterized by being configured.

According to the capacitor of the fourth aspect, the plug body 18 for closing the opening 15 of the plug member 14 is provided.
By providing the, when a load exceeding the rating is applied,
That is, when the internal temperature of the outer case 2 abnormally rises, or when gas is suddenly generated by applying an overvoltage,
When the internal pressure of the outer case 2 rises, the plug 1
Since 8 can be disengaged to release the internally generated gas to the outside, it is possible to prevent the outer case 2 from being broken. As a result, the safety during the overload can be improved.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Next, specific embodiments of the capacitor of the present invention will be described in detail with reference to the drawings.

1A and 1B are views showing the structure of a characteristic portion of a capacitor according to a first embodiment of the present invention. FIG. 1A is a schematic sectional view thereof, and FIG. 1B is an exploded perspective view thereof. ing. In FIGS. 1A and 1B, 1 is a capacitor element, 2 is an outer case that covers the entire periphery of the capacitor element 1, and the outer case 2 is filled with an organic electrolyte solution (not shown). The outer case 2 is formed by sealing a laminated film obtained by stacking a metal foil and a plastic film, and the inside of the outer case 2 is configured to be hermetically sealed.
A pair of plate-shaped lead plates 3 and 3 are mounted side by side at the ends of the capacitor element 1. The other ends of the lead plates 3 and 3 are separated from the sealing portion of the outer case 2. It is provided so as to project to the outside. Here, the dotted line portion in the drawing indicates the position where the gas release valve having the oil seal structure is mounted. Hereinafter, this gas release valve will be described in more detail with reference to FIG.

2A and 2B are views for explaining the gas discharge valve of the condenser according to the first embodiment, wherein FIG. 2A is a schematic sectional view thereof, and FIG. 2B is an exploded perspective view thereof. That is, the gas release valve 5 attached to the inner surface of the outer case 2 is configured to remove the decomposition gas generated inside the outer case 2, that is, the internally generated gas such as carbon monoxide or carbon dioxide.
It is configured so that it can be released to the outside. Specifically, the gas release valve 5 includes a cover portion 6 having a substantially concave shape in cross section, and a flange portion 6a formed around the end portion of the cover portion 6 is provided on the inner surface of the outer case 2. It is welded. Further, a vent hole 7 is formed at the center of the bottom surface of the cover portion 6 so as to penetrate the cover portion 6, and silicone oil 8 is applied to the entire bottom surface inside the cover portion 6 so as to close the vent hole 7. Has been done. Further, a film 9 having a diameter slightly smaller than the inner diameter of the cover portion 6 is laminated on the upper side of the silicone oil 8.
And a film holder 10 provided between the outer case 2 and the outer case 2.
Thus, the film 9 is pressed against the silicone oil 8 side. Further, the outer case 2 is formed with a pinhole 4 for releasing the gas to the outside through the gas release valve 5.

With the above construction, even if a decomposition gas is generated inside the outer case 2 due to electrolysis of the organic electrolytic solution of the capacitor element 1 or the like, the decomposition gas is not removed from the cover portion 6. After entering the gas release valve 5 through the vent hole 7 and passing through the gap between the outer peripheral end of the silicon oil 8 and the film 9 and the cover portion 6, the gas is released from the pinhole 4 to the outside of the outer case 2. Will be done. As a result, the outer case 2 is swollen by the decomposition gas generated inside the outer case 2 and the seal is broken,
It is possible to prevent the seal from being damaged.

Here, for example, in an electric double layer capacitor using an organic electrolytic solution, when electric power is applied at 70 ° C. and 3.0 V, the gas release valve 5 is not provided, and within 1000 hours. The seal broke due to the remarkable swelling of the outer case 2. However, in the case of the condenser having the gas release valve 5 shown in this embodiment, 300
The outer case 2 did not swell even after 0 hour, and the seal did not break.

Next, a second embodiment of the capacitor of the present invention will be described. In this embodiment, as compared with the first embodiment, the gas generated inside the outer case 2 is selectively transmitted through the outside of the gas release valve 5 welded to the inner surface of the outer case 2 of the capacitor. It is different in that it is covered with a selective gas permeable film 11 (selective gas permeable material) that can be used (see FIG. 3). That is, the selective gas permeable film 11 in this embodiment is formed of a material capable of selectively permeating carbon monoxide or carbon dioxide generated inside the outer case 2, and The gas release valve 5 is covered with 11, and the peripheral edge of the selective gas permeable film 11 is welded to the inner surface of the outer case 2. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As described above, by covering the gas release valve 5 with the selective gas permeable film 11, carbon monoxide and carbon dioxide generated in the outer case 2 are transmitted and released to the outside. It is possible to prevent oxygen, water, etc. that enter from the inside. Further, by providing the selective gas permeable film 11, it is possible to prevent the organic electrolytic solution existing in the outer case 2 from leaking to the outside together with the gas release. As a result, it is possible to prevent the breakage of the seal due to the bulging of the outer case 2 and improve the stability of the electrical characteristics for a long period of time.

Further, a third embodiment of the capacitor of the present invention will be described. FIG. 4 is a partial perspective view showing the structure of a characteristic part of the capacitor in this embodiment, and FIG. 5 is a sectional view thereof. First, reference numeral 2 shown in FIG. 4 denotes an outer case formed by sealing a laminated film obtained by laminating a metal foil and a plastic film, and a pair of lead plates 3 extending from the capacitor element housed in the outer case 2. The other end portions of 3 are provided so as to respectively project from the seal portion 13 of the outer case 2. A plug member 14 having a substantially convex cross section is provided between the lead plates 3 and 3 to form the outer case 2.
It is welded while being sandwiched between the seal portions 13. Figure 5
As shown in FIG. 3, the spout member 14 is formed with an opening 15 for communicating the inside and outside of the outer case 2, and the opening 15 further includes a gas (carbon monoxide) generated inside the outer case 2. It is closed by a selective gas permeable film 11 capable of selectively permeating carbon dioxide). More specifically, the selective gas permeable film 1 described above.
1 is two silicone rubbers 1 having a hole 16a in the center
It is provided so as to be sandwiched between 6 and 16, and is configured to be closed by filling it in the opening 15 (see FIG. 5).

With the above-mentioned structure, the decomposed gas generated inside the outer case 2 can be removed from the opening 1
5 into the plug member 14 and one silicone rubber 1
The gas is discharged to the outside of the outer case 2 through the holes 16a of 6 through the selective gas permeable film 11 and the holes 16a of the other silicon rubber 16, respectively. As a result, it is possible to prevent the destruction of the seal due to the expansion of the outer case 2 with a simple structure. Further, the selective gas permeable film 11 can release the decomposed gas generated inside the outer case 2 to the outside, while blocking oxygen and water entering from the outside. Furthermore, the outer case 2
It is also possible to prevent the electrolyte solution present inside from leaking outside together with the gas release. As a result, it is possible to improve the stability of electrical characteristics for a long period of time.

Next, a fourth embodiment of the capacitor of the present invention will be described. In this embodiment, as compared with the third embodiment, the seal portion 1 of the outer case 2 of the capacitor is provided.
3 is different in that the opening 15 of the plug member 14 sandwiched by 3 is plugged with a plug 18 such as silicon rubber to close the opening 15. FIG. 6 shows a schematic sectional view thereof. The plug 18 in this embodiment is
When a load higher than the rating is applied, that is, the outer case 2
When the internal pressure of the outer case 2 rises, for example, when the internal temperature of the battery abnormally rises or when decomposed gas is suddenly generated by applying an overvoltage, the plug 18 is removed and the decomposed gas inside is removed. It is configured to be released to the outside of. In this embodiment, the same components as those of the third embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As described above, since the opening 15 of the plug member 14 is provided with the plug 18 for closing it,
When the internal pressure rises when a load (voltage or temperature) higher than the rated value is applied, the plug 18 can be released to release the gas to the outside, so that the outer case 2 is prevented from being destroyed. You can As a result, the safety at the time of overload can be improved.

Although specific embodiments of the capacitor of the present invention have been described above, the present invention is not limited to the above embodiments, and various modifications can be made within the scope of the present invention. It is possible. That is, the specific structures of the gas release valve 5 and the plug member 14 and the positions where they are provided in each of the above-described embodiments are not limited to the above-described embodiments, and various configurations are possible as long as the gist thereof is not impaired. It is possible to change.

[0025]

According to the capacitor of the first aspect, the gas generated inside the outer case can be released to the outside from the pinhole through the gas release valve. It can be prevented from being damaged.

According to the second aspect of the present invention, the gas (for example, carbon monoxide or carbon dioxide) generated inside the outer case can be released to the outside, while the oxygen and water entering from the outside can be blocked. It will be possible. Further, by providing this selective gas permeable material, it is possible to prevent the electrolytic solution existing in the outer case from leaking to the outside together with the gas release. As a result, it is possible to prevent the airtightness from being impaired by the bulging of the outer case and to improve the stability of the electrical characteristics for a long period of time.

According to the capacitor of the third aspect, the gas (for example, carbon monoxide or carbon dioxide) generated inside the outer case can be released to the outside, while the oxygen and water entering from the outside can be blocked. It will be possible. Further, by providing this selective gas permeable material, it is possible to prevent the electrolytic solution existing in the outer case from leaking to the outside together with the gas release. As a result, with a simple structure, it is possible to prevent the breakage of the seal due to the bulging of the outer case and improve the stability of the electrical characteristics for a long period of time.

According to the capacitor of the fourth aspect, the internal pressure rise when a load (voltage or temperature) higher than the rated value is applied by providing a plug body for closing the opening part of the plug member. At this time, since the plug can be detached to release the internally generated gas to the outside, it is possible to prevent the outer case from being broken. As a result, the safety during the overload can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a characteristic portion of a capacitor according to a first embodiment of the present invention, in which (a) is a schematic sectional view,
(B) is an exploded perspective view thereof.

2A and 2B are views for explaining the gas discharge valve of the condenser according to the first embodiment, wherein FIG. 2A is a schematic sectional view and FIG. 2B is an exploded perspective view thereof.

FIG. 3 is a partial enlarged cross-sectional view for explaining a capacitor which is a second embodiment of the present invention.

FIG. 4 is a partial perspective view showing a structure of a characteristic portion of a capacitor which is a third embodiment of the present invention.

FIG. 5 is a schematic sectional view of a capacitor according to the third embodiment.

FIG. 6 is a schematic sectional view of a capacitor which is a fourth embodiment of the present invention.

[Explanation of symbols]

1 Capacitor element 2 exterior case 3 lead plate 4 pinholes 5 gas release valve 6 Cover 7 vents 8 silicone oil 9 films 11 Selective gas permeable film (selective gas permeable material) 13 Seal part 14 Plug member 15 openings 18 plug

Claims (4)

[Claims] 1. A capacitor having an outer case (2) formed of a material obtained by laminating a metal foil and a plastic film, wherein a gas release valve (5) having an oil seal structure is mounted inside the outer case (2). At the same time, the outer case (2) is provided with a pinhole (4) for releasing gas from the gas release valve (5) to the outside. 2. The capacitor according to claim 1, wherein the gas release valve (5) is covered with a selective gas permeable material (11) which selectively permeates an internally generated gas. 3. A capacitor having an outer case (2) formed by sealing a material obtained by laminating a metal foil and a plastic film, and a cap member (14) is sandwiched between the sealing part (13). A condenser characterized in that the opening (15) of the plug member (14) is closed by a selective gas permeable material (11) that selectively permeates an internally generated gas. 4. A capacitor having an outer case (2) formed by sealing a material obtained by laminating a metal foil and a plastic film, and a cap member (14) is sandwiched between the sealing portion (13). Then, while the opening (15) of the spout member (14) is closed by the plug body (18), when the internal pressure of the outer case (2) rises, the plug body (18) comes off and the outer case ( 2) A capacitor characterized in that it internally discharges internally generated gas.