JPH10106524A - Electric parts - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the breaking pressure of an explosion preventing valve constant with the simple structure by providing a resin cover for the sealing case with an explosion preventing valve, which is made of a thin metal and provided with grooves and which is to be broken when inner presser of a case is raised. SOLUTION: A cover 10 for sealing a case is provided with a through hole 14 at a nearly central part of a main body 12 made of resin, and has an explosion preventing valve 16 made of metal, which is insert molded so as to close the through hole 14. Material, diameter and plate thickness of the explosion preventing valve 16 are decided in response to a set value of the breaking pressure, and an outside surface thereof is provided with a predetermined shaped groove 17 having a V-shaped cross section. The groove 17 receives the pressure to be applied to the explosion preventing valve 16 with the rise of the pressure inside of the case, and when the pressure applied to the explosion preventing valve 16 exceeds the predetermined value, the explosion preventing valve 16 is broken along the groove 17. With this structure, breaking pressure of the explosion preventing valve 16 can be maintained constant with the simple structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric component such as an electric double layer capacitor and a wound rectangular battery. More specifically, the present invention relates to an electrical component having an explosion-proof valve that has a constant operating pressure at which it breaks and is easy to manufacture.

[0002]

2. Description of the Related Art In recent years, electric components such as electric double-layer capacitors and wound type square batteries play an important role in miniaturizing electronic devices and efficiently using solar energy. For example, various types of electrolytic capacitors represented by electric double-layer capacitors are used as driving power sources and power sources for various consumer products, and are used in combination with solar cells for optical display systems such as road signs. Demand is growing. In addition, wound-type rectangular batteries such as lithium-ion batteries are one of the key components of portable electronic devices such as mobile phones and computers that have been rapidly spreading in recent years.

[0003] Electric components such as electric double layer capacitors and wound rectangular batteries are usually prepared by immersing electrode materials and the like in an electrolyte solution inside an outer case made of resin.
Sealed.

FIG. 6 shows a sectional view of an example of an electric double layer capacitor as such an electric component. The structure will be described below with reference to FIG.

[0005] The electric double-layer capacitor 100 is hermetically sealed by a resin outer case 101 and a lid 102. Activated carbon electrodes 105 and 106 partitioned by a separator 104 are accommodated inside the outer case 101.
Outside the activated carbon electrodes 105 and 106, current collecting cases 109 and 11 are provided by conductive adhesives 107 and 108, respectively.
0 is adhered. The separator 104, the activated carbon electrodes 105 and 106, the conductive adhesive 107,
8. An electrode group is constituted by the current collecting cases 109 and 110. Then, this electrode group is loaded in the outer case 101, impregnated with the electrolytic solution 111, and sealed with the lid 102. The lid 102 is charged with electricity,
A positive electrode terminal and a negative electrode terminal for extracting a current are provided.

An ion permeable film is used as the separator 104, and its thickness is usually about 100 μm.
The activated carbon electrodes 105 and 106 are formed by mixing activated carbon, AB (acetylene black), and PTFE (polytetrafluoroethylene) at a predetermined compounding ratio, and molding, and each functions as an electrode material. Current collecting case 109,
Reference numeral 110 denotes a positive electrode and a negative electrode activated carbon electrode 105, respectively.
It functions as a metal tray for accommodating 106. The current collecting cases 109 and 110 have leads connected to the electrode terminals 113 or 114. The electrode group sandwiched between such current collecting cases 109 and 110 is the outer case 1
After being housed in the housing 01, it is pressed by a spring 112 at a constant pressure. The reason why such a spring 112 is provided is that the current collecting cases 109 and 110;
05, 106: This is for preventing the internal resistance from increasing by always pressing each member of the separator 104 under a constant pressure and bringing the members into close contact with each other.

The electric double layer capacitor 10 described above
0 is designed so that the strength of the outer case 101, the lid 102, and the joint thereof can sufficiently withstand fluctuations in internal pressure under normal operating conditions.
However, for example, when the battery is overcharged beyond the rated charging condition at a high temperature exceeding the rated use temperature, the capacitor 10
This is not to say that excessive gas is generated inside 0 and the pressure does not rise. Therefore, it is desirable to provide an explosion-proof valve in such a case from the viewpoint of fail-safe which can cope with any case.

FIGS. 7 (a) and 7 (b) are a plan view and a partial cross-sectional view showing a prototype example in which such an explosion-proof valve is applied to a lid. In this prototype example, the lid 1 of the capacitor 100 is used.
Near the center of 02, a thin portion 120 in which the thickness of the resin is reduced in a circular shape is provided. This thin portion 120 functions as an explosion-proof valve. That is, when the pressure inside the electric double layer capacitor 100 rises abnormally, the outer case 1
01, the thin portion 120 is broken before the lid 102 or the joint thereof is broken, releasing excess gas inside the capacitor 100 to the outside, lowering the pressure and preventing abnormal rupture.

[0009]

In the prototype of the explosion-proof valve described above, the explosion-proof valve is formed by forming a thin portion 120 on a part of the lid. Such a resin member having the thin portion 120 as an explosion-proof valve is integrally manufactured by molding. However, the dimensional accuracy of a resin molded product obtained by molding may not always be sufficiently high. That is, the thickness and diameter of the thin portion vary. As a result of such variations in the thickness and diameter of the thin portion 120, the breaking pressure of the explosion-proof valve also varies.

On the other hand, in a molded article, non-uniformity of resin generally called "su" may occur.
If such “swelling” occurs in the thin-walled portion 120 as an explosion-proof valve, the breaking pressure of the explosion-proof valve becomes lower than a design value. That is, the explosion-proof valve may be broken in a pressure range lower than the design value.

Here, a method is considered in which a groove having a predetermined shape is formed in the thin portion 120 and stress is concentrated on the groove so that the rupture location and the rupture mode are constant to stabilize the rupture pressure of the explosion-proof valve. Can be However, it is not easy to form such fine grooves by resin molding. Also, after molding, a thin portion 120
Also, it is not easy to form a groove by cutting off, and if such a step is added, the manufacturing cost increases.

On the other hand, if a metal piece such as aluminum is used for the explosion-proof valve, the dimensional accuracy is improved and the processing is facilitated. Thereby, the above-mentioned problems such as the variation in the rupture pressure are solved. However, if such a metal piece is attached and fixed to the resin lid after molding in an airtight state, the number of steps is increased and the cost is increased.

As described above, the prototype electric component has a problem that it is not easy to obtain an explosion-proof valve having a stable breaking pressure by a simple process.

The present invention has been made in view of such a point. That is, the present invention provides an improved electric component having a simple structure and having a constant breaking pressure of an explosion-proof valve.

[0015]

That is, an electric component according to the present invention comprises an electric double-layer capacitor element or a wound battery element in which a positive electrode and a negative electrode divided by a separator are disposed in a substantially flat rectangular case. Insert the internal element of
In an electric component such as an electric double layer capacitor or a prismatic battery having a structure in which the case is sealed with a lid through which a positive electrode lead and a negative electrode lead penetrate, the lid has a thin-walled, grooved metal that can be broken when the internal pressure of the case is increased. The explosion-proof valve is installed.

Further, the electric component according to the present invention has such a configuration, and further, the lid is molded, and the explosion-proof valve is insert-molded to the lid. It has a characteristic configuration.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION In an electric part according to the present invention, an explosion-proof valve having a lid into which a metal piece such as aluminum which is easily broken is incorporated is used. That is, by inserting and molding a metal piece into the lid, an explosion-proof structure that is easy to assemble and has a constant breaking pressure is obtained.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. Here, an electric double layer capacitor will be described as an example of the electric component according to the present invention.

FIGS. 1A and 1B are a plan view and a partial cross-sectional view of a lid 10 as a main part of an electric double layer capacitor according to the present invention. The lid 10 shown in the figure differs from the conventional lid 102 shown in FIG. 7 in the explosion-proof valve part. That is, the lid 10 shown in FIGS.
A circular through-hole 14 is provided substantially at the center of the resin-made main body 12, and a metal explosion-proof valve 16 is insert-molded so as to close the through-hole 14. As a material of the explosion-proof valve 16, for example, aluminum can be used.
As a material of the resin of the main body 12, for example, PPS (polyphenylene sulfide) can be used. Then, such a resin material is poured into a mold by, for example, an injection molding method to form the lid 10. At this time, the explosion-proof valve 16 together with the electrode terminals 18 and 19 can be arranged at a predetermined position in a mold and can be embedded in a resin by insert molding.

FIGS. 2 (a), 2 (b) and 2 (c) show the explosion-proof valve 1 before being insert-molded into the lid 10, respectively.
6 and its (i)-(i) lines and (i)
It is sectional drawing cut | disconnected by the i)-(ii) line. Explosion-proof valve 16
Has a substantially disc-like shape, the diameter of which is, for example, 10 m
m, the plate thickness can be, for example, 100 μm.
However, the material, diameter, and plate thickness can be appropriately determined according to the set value of the breaking pressure. Explosion-proof valve 16
Has a groove 17 of a predetermined shape formed on one surface thereof. This groove has a V-shaped cross section, and its depth can be, for example, about 70 μm from the surface.
By providing such a groove, the stress applied to the explosion-proof valve 16 as the internal pressure of the electric component increases can be concentrated on the groove. That is, when a certain pressure is applied, the rupture can be preferentially broken along the groove, and the rupture pressure of the explosion-proof valve 16 can be stabilized.

The shape of the groove 17 is, for example, as shown in FIG.
7a, and the grooves 17b can be formed radially from the arc toward the periphery. By forming the groove in such a shape, the explosion-proof valve 16 can
, A portion of the explosion-proof valve 16 opens outwardly, which facilitates the release of gas inside the condenser.

Next, a process for manufacturing an electric double layer capacitor using such an explosion-proof valve 16 will be described.

FIGS. 3A to 3E are perspective views for explaining an assembling process of the electric double layer capacitor 30 according to the present invention using the explosion-proof valve 16 as shown in FIGS. First, as shown in FIG. 1A, the activated carbon electrodes 32 and 33 on the positive electrode side and the negative electrode side are respectively connected to the conductive adhesive 3.
They are housed in the current collecting cases 36 and 37 by 4 and 35, respectively, and fixed by adhesion. Next, the activated carbon electrodes 32 and 33 provided with the current collecting cases 36 and 37 are stacked with the partitioning separator 38 interposed therebetween.

The components thus laminated together with the spring 40 are bundled and integrated with an adhesive tape 42.

The heat-shrinkable tubes 46 and 47 used for connection with the electrode terminals are fitted into the current-carrying leads 44 and 45 of each current collecting case.

Next, as shown in FIG. 2B, the components integrated by the adhesive tape 42 are separated from each other by the outer case 5.
Housed in 0.

Further, as shown in FIG. 3C, an electrolytic solution 52 is injected into the outer case 50.

Next, as shown in FIG. 2D, the current-carrying leads 44 and 45 of the current collecting cases 36 and 37 and the terminals 18 and 19 of the lid 10 are connected to the heat-shrinkable tubes 46 and 4 respectively.
7 for connection. Then, the explosion-proof valve 16 joins the insert-molded lid 10 and the outer case 50 by low-frequency welding to complete the electric double-layer capacitor 30 as shown in FIG.

The explosion-proof valve 16 of the electric double layer capacitor manufactured in this manner needs to be broken when a load exceeding the rated operating condition is applied to the capacitor and the internal pressure rises abnormally. Is done. Here, the upper limit of the rated operating temperature of this electric double layer capacitor is 70 ° C. The upper limit of the rated operating voltage is 2.3 volts. And the condition of this upper limit value, that is, 70 ° C., 2.3
When a capacitor is operated with volts, its internal pressure rises to 5 kg per square centimeter. Therefore, as the lower limit of the burst pressure of the explosion-proof valve 16,
Desirably, the weight is 5 kg per square centimeter.

On the other hand, the explosion-proof valve 16 needs to be broken before the outer case bursts. Here, the pressure resistance of the outer case is about 10 k per unit square centimeter.
g. Therefore, the upper limit of the burst pressure of the explosion-proof valve needs to be 10 kg or less per square centimeter.

From the above conditions, the burst pressure of the explosion-proof valve 16 should be 10 kg at 5 kg or more per unit square centimeter.
g.

The inventor examined the burst pressure of the explosion-proof valve of the electric double layer capacitor according to the present invention. Here, those shown in FIGS. 1 and 2 were used as explosion-proof valves. Also,
Aluminum was used as the material of the explosion-proof valve 16. The diameter of the through-hole 14 in the main body 12 of the lid for inserting and molding the explosion-proof valve 16 was 4 mm. As a result, the thickness of the explosion-proof valve 16 was 100 μm and the depth of the groove 17 was 70 μm.
m, that is, when the remaining plate thickness is 30 μm, the breaking pressure is 8 kg per unit square centimeter.
Was obtained stably. In other words, if an explosion-proof valve of such dimensions is used, the internal gas can be released safely and reliably before the outer case ruptures when operated beyond the rated operating conditions, and the rupture It was found that the reproducibility of the pressure was good.

The explosion-proof valve for an electric component according to the present invention is not limited to the one shown in FIG.

FIGS. 4A to 4D are plan views showing a modification of the explosion-proof valve that can be used for the electric component according to the present invention. Each explosion-proof valve shown in the figure has a rectangular plate shape instead of the disk shape shown in FIG.

The explosion-proof valve 60A shown in FIG. 5A has a groove 62 formed in the center of a rectangular plate piece and formed substantially from end to end in the longitudinal direction. When this explosion-proof valve 60A breaks along its groove, it forms an elongated opening and releases the gas inside.

The explosion-proof valve 60B shown in FIG. 3B has two grooves 63A and 63B that intersect in a rectangular diagonal direction. The explosion-proof valve 60B is broken along the grooves 63A and 63B, and when the four separated pieces are opened outward, a substantially rectangular opening is formed at the center thereof, and the gas inside is released.

The explosion-proof valve 60C shown in FIG. 3C has two U-shaped grooves 64A and 64B which are respectively opposed to both sides in the longitudinal direction from the center. This explosion-proof valve 60C
When ruptured along the grooves 64A, 64B, each of the U-shaped portions opens outward to form two independent openings, releasing the gas inside.

The explosion-proof valve 60D shown in FIG. 4D has two U-shaped grooves 65A and 65B similar to the explosion-proof valve 60C shown in FIG. 4C, and one straight line connecting them. Groove 65
C. When this explosion-proof valve 60D is torn along its groove, each of the U-shaped portions and the remaining portion open outward, forming one opening at the center and separating to release the gas inside.

The grooves having various shapes as described above can be formed by, for example, a pressing method using a mold. Moreover, it can also be formed by cutting. Further, these grooves may be formed only on one side of the aluminum piece serving as the explosion-proof valve, or may be formed on both sides.

The material of such an explosion-proof valve is not limited to aluminum described above. As the material, for example, an organic material or an inorganic material can be used in addition to a metal such as stainless steel or nickel. That is, any material can be used as long as it has a constant breaking pressure, can be insert-molded into the resin lid body, and satisfies conditions such as not being corroded by the electrolytic solution.

The cross-sectional shape of the through-hole of the resin portion for insert-molding these explosion-proof valves can be appropriately selected from various shapes such as a rectangle and an ellipse. Further, the position where such an explosion-proof valve is installed is not limited to the central portion of the lid as described above. As another installation location, for example, a side surface or a bottom surface of the outer case itself may be used.

Here, from the standpoint of the ease of the insert molding process, it is desirable to install on the bottom surface of the outer case. This is because it is necessary to pull out the outer case from the mold after molding. That is, when the explosion-proof valve is installed on the side surface of the outer case, when the outer case is pulled out of the mold, the mold at the portion of the through hole for insert-molding the explosion-proof valve becomes an obstacle. Therefore, it is necessary to slide and retract the mold in that portion, which complicates the mold and complicates the process. On the other hand, when the explosion-proof valve is installed on the bottom surface of the outer case, when the outer case is pulled out of the mold, the mold at the portion of the through hole into which the explosion-proof valve is insert-molded does not interfere.

The electric component according to the present invention is not limited to the electric double layer capacitor described above. As another electric component, for example, a wound rectangular battery can be cited.

FIGS. 5A and 5B are diagrams for explaining the structure of a lithium ion secondary battery which is an example of such a wound rectangular battery. That is, FIG. 1A is a cross-sectional explanatory view showing the entire configuration. FIG. 1B is a conceptual diagram illustrating the structure of the sheet-like electrode.

As can be seen from FIG.
The ion secondary battery 70 has a structure in which a laminated sheet-like electrode group 73 is wound and housed in a resin outer case 71 together with an electrolytic solution. The electrode group 73 includes a separator 74, a positive electrode body 75, and a separator 7 as shown in FIG.
6. A negative electrode body 77 is laminated in this order. The positive electrode body 75 has a structure in which a positive electrode current collector 80 is sandwiched between positive electrode materials 81. This positive electrode current collector 80 is made of an aluminum foil. Further, this positive electrode material 81 is made of L
It is a mixture of iCoO2, a binder, and a conductive material. On the other hand, the negative electrode body 77 has a structure in which a current collector 83 is sandwiched between negative electrode materials 84. The current collector 83 is made of a copper foil. This negative electrode material 84 is a mixture of carbon and a binder.

The lithium ion secondary battery 70 shown in FIG. 5A has an explosion-proof valve 86 on a lid 72 which fits into a resin outer case 71 that accommodates the electrode group 73. That is, an aluminum piece having a groove of a predetermined shape formed on its surface is insert-molded as an explosion-proof valve 86 in the lid 72 of the battery. By insert-molding such an aluminum piece, the explosion-proof valve 86 operates accurately at a predetermined pressure, for example, when the internal pressure of the battery abnormally rises due to overcharging or the like at a high temperature exceeding the rated condition. In addition, excess gas inside the battery can be released safely and reliably.

[0047]

The present invention is embodied in the form described above, and has the following effects.

First, the electric component according to the present invention has an explosion-proof valve with higher dimensional accuracy than before and a stable breaking pressure. As a result, when the electrical component is used under the conditions outside the rated operating conditions and its internal pressure rises abnormally, the excess gas inside the electrical component is released accurately and reliably when the specified pressure is reached. Can be done. That is, it is possible to provide a safe and easy-to-use electric component.

Further, in the electric component according to the present invention, such a high-precision explosion-proof valve can be installed only by insert-molding a metal piece such as aluminum into a resin lid. Therefore, an electric component having an explosion-proof valve with a stable rupture pressure can be manufactured without an increase in the number of assembling man-hours and in the manufacturing cost.

As described above, the present invention has an extremely remarkable industrial effect, and its value is extremely large.

[Brief description of the drawings]

FIG. 1 is a plan view and a partial cross-sectional side view of a lid 10 of an electric double layer capacitor according to the present invention.

FIG. 2 is a plan view of an explosion-proof valve 16 before being insert-molded into a lid 10, and (i)-(i) lines and (i) of FIG.
It is sectional drawing cut | disconnected by the i)-(ii) line.

FIG. 3 is a perspective view illustrating an assembling process of the electric double layer capacitor 30 according to the present invention using the explosion-proof valve 16 as shown in FIGS. 1 and 2;

FIG. 4 is a plan view showing a modified example of an explosion-proof valve that can be used for an electric component according to the present invention.

FIG. 5 shows lithium lithium as an example of a wound prismatic battery.
FIG. 2 is an explanatory diagram of a structure of an ion secondary battery.

FIG. 6 is a cross-sectional view of a general electric double-layer capacitor.

FIG. 7 is a plan view and a partial cross-sectional view of a lid manufactured by the present inventor on a trial basis.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Lid 12 Main body 14 Through-hole 16 Explosion-proof valve 17a, 17b Groove 18, 19 Electrode terminal 30 Electric double layer capacitor 32, 33 Activated carbon electrode 35, 36 Current collecting case 38 Separator 40 Spring 42 Adhesive tape 44, 45 Electric lead part 46, 47 Heat shrink tube 50 Outer case 52 Electrolyte 60A, 60B, 60C, 60D Explosion-proof valve 62, 63A, 63B, 64A, 64B Groove 65A, 65B, 65C Groove 70 Lithium ion secondary battery 71 Outer case 72 Cover 73 Electrode group 74, 76 separator 75 positive electrode body 77 negative electrode body 80 positive electrode current collector 81 positive electrode material 83 negative electrode current collector 84 negative electrode material 85 negative electrode lead plate 86 explosion-proof valve 87, 88 electrode terminal 100 electric double layer capacitor 101 outer case 102 lid 104 separator 105,106 activated carbon Electrode 107 conductive adhesive 109,110 collector case 111 electrolyte 112 Springs 113, 114 electrode terminals 120 thin portion

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tatsuya Yamazaki 5-36-11 Shimbashi, Minato-ku, Tokyo Inside Fuji Electric Chemical Co., Ltd. (72) Inventor Kazuo Takada 5-36, Shimbashi, Minato-ku, Tokyo No. 11 Fuji Electric Chemical Co., Ltd.

Claims (2)

[Claims] 1. An internal element such as an electric double layer capacitor element or a wound battery element having a positive electrode and a negative electrode separated by a separator is inserted into a substantially flat rectangular case.
In an electric component such as an electric double layer capacitor or a prismatic battery having a structure in which the case is sealed with a lid through which a positive electrode lead and a negative electrode lead penetrate, the lid has a thin-walled, grooved metal Electrical parts characterized by the installation of explosion-proof valves. 2. The method according to claim 2, wherein the lid is molded.
The electric component according to claim 1, wherein the explosion-proof valve is insert-molded to the lid.