JPS6336127B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a power storage device that has good electrical characteristics and has a so-called self-protection function that does not cause combustion or smoke when damaged due to overvoltage or the like.

In capacitors, which use paper or plastic film as a dielectric and metal is vapor-deposited on the surface to form electrodes, when a short circuit occurs between opposing electrodes of different types due to insulation defects such as conductive particles or pinholes in the dielectric,
It has a so-called self-healing function in which the vapor deposited film in the vicinity of the short circuit is scattered by the thermal energy generated by the short circuit current, and the insulation between the opposing electrodes of different types is restored. However, in cases where the dielectric material absorbs moisture in high humidity environments, resulting in a uniform drop in insulation properties, or when overvoltage is applied, or even when the dielectric material is used at high temperatures, where insulation properties are significantly reduced, In this case, the short-circuit current becomes extremely excessive due to factors such as the short-circuit current flowing at many points simultaneously, and the self-recovery function is unable to follow up and the short-circuits concentrate instantly, causing the capacitor to burn or smoke and burn out. There are things to do. This leads to the risk of inducing a fire, which is an extremely serious problem in terms of disaster prevention, and conventionally various safety devices have been added and used.

On the other hand, in recent years, in multilayer structure capacitors, when an excessive short-circuit current flows beyond the limit for the self-recovery function to function normally due to the concentration of the short-circuit current, metallicon (sprayed metal) is used to supply this current. A capacitor designed to scatter the deposited film in the vicinity was devised. This type of laminated structure capacitor has a structure in which a large number of small-capacity unit capacitors each having a small-area opposing electrode are stacked and connected in parallel. When an excessive short-circuit current flows through one unit capacitor, the vapor deposited film near the metallicon instantly scatters due to Joule heat, acting like a fuse and insulating and separating the unit capacitor, thereby avoiding burnout. Furthermore, there is a capacitor formed with a vapor deposition pattern as shown in FIG. 1, which attempts to realize the self-safety function of a capacitor with a laminated structure in a conventional capacitor with a wound structure.

In this method, metal vapor deposited electrodes A ₁ and B 1 are formed on one side of dielectric materials A and B made of paper or plastic film, respectively, and electrically isolated from each other by comb-shaped vapor deposited electrode margins A ₂ and _{B 2 .} However, it is constructed by stacking these two metallized dielectrics and applying metallicon to the end surfaces of the wound layers. In addition to this example, the margin of the vapor-deposited electrode of dielectric B is not comb-shaped but a straight line along one end surface as in the conventional case, or the margin of the vapor-deposited electrode of dielectric B is formed on both sides. A capacitor of the same type may also include one in which one electrode pattern is formed on the other hand and the other is made of a dielectric material that is not metallized.

In any case, at least one of the opposing dissimilar electrodes is formed of a metal vapor deposited film that is insulated and separated from each other, and in a unit capacitor composed of each vapor deposited electrode, at the moment an excessive short circuit current flows, the insulation The electric connection between the separated vapor deposition electrode and the metallicon is avoided by scattering the vapor deposited film in the vicinity of the metallicon, thereby avoiding burnout.

However, such a capacitor having a self-protection function with a winding structure has the following disadvantages. In other words, it is necessary for the electrical properties of the electrodes, which are formed by vapor deposition while insulating them from each other, to have a good electrical connection with the metallicon metal layer. Poor connection is likely to occur due to misalignment or disordered winding.
It is extremely difficult to avoid this.

If the electrical connection is not good, a predetermined capacity cannot be obtained or tan δ increases due to contact resistance, making it difficult to obtain a capacitor with good electrical characteristics. Furthermore, when charging/discharging current and self-recovery function,
Due to the current, which is not originally excessive, disadvantageous results such as the connection at this portion scattering tend to occur.

In view of the above-mentioned problems, the present invention provides a capacitor having a wound structure that has a self-protection function and has good electrical characteristics.The details thereof will be described below using examples.

FIG. 2 shows the shape of the metal vapor-deposited electrode in A of the two dielectrics A and B constituting the capacitor of the present invention. This is similar to Fig _. 1 in that the metal vapor deposition electrode A1 is separated by vapor deposition electrode margins _A2 and _A3 that are formed approximately in a comb shape along the winding direction, but it is different. The point is that each electrode _A1 is not completely insulated from each other,
It is connected by two or more connecting portions A ₄ on the line of the vapor deposition electrode margin A ₃ in the width direction. Now, when an excessive short circuit occurs at point P shown in FIG. 2, the short circuit current flows along the path shown by the thick arrow.

In the figure, the current indicated by the downward arrow is the current supplied from the metallicon layer. As mentioned above, these currents scatter the vapor deposited film near the metallicon, but on the other hand, the vapor deposited film at the connection part _A4 is also scattered at the same time one after the other. , the electrode _A1 is completely separated from other adjacent similar electrodes, and the expansion of the short circuit is prevented, so that the capacitor can avoid burning out. On the other hand, during normal operation, each electrode A ₁ connects to the connecting part A ₄
Since they are connected to each other by , even if there is a defective electrical connection with the metallicon, a predetermined capacity can be obtained and tan δ is also good. It is clear that this can be achieved by appropriately setting the length and width of the vapor deposition electrode margin _A3 , in other words, the length and width of the connecting portion _A4 in the winding width direction.

In the capacitor of the present invention, a single-sided metallized dielectric material A shown in FIG. 2 and a single-sided metalized dielectric material B having a symmetrical electrode shape are stacked and wound, and metallicon is applied to the end surfaces. obtained by. In another embodiment, the dielectric B does not form a comb-shaped deposited electrode margin B ₃ (not shown), but a straight deposited electrode margin B ₂ along the end face (not shown). It is also possible to form only one (without). Furthermore, as another example, metallized dielectric A
It is clear that similar capacitors can be obtained by stacking and winding the electrodes on both sides of the dielectric B and the dielectric B on which no vapor deposition is applied. In this case as well, the shape of the electrode on at least one of the front and back sides may have a vapor deposition electrode margin in the winding width direction as shown in FIG.

The electricity storage device of the present invention having the above configuration is as follows:
It has the following effects:

(1) Since the electrodes of the capacitor are connected to each other through two or more connecting parts, the capacitance will not decrease or the tan δ will not deteriorate even if the winding is disordered during manufacturing.

(2) Even if a short-circuit current exceeding the limit of the self-recovery function occurs, the vapor-deposited film in the connection area and near the metallicon scatters, thereby preventing the short-circuit from progressing and burning out the capacitor.

(3) Even in a capacitor with a wound structure, both good electrical characteristics and a self-safety function can be achieved.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional capacitor when it is wound;
The figure is a plan view of one embodiment of a metallized dielectric for use in a capacitor according to the invention. A...Dielectric material, _A1 ...Metal deposited electrode, _A2 , _A3
...Deposition electrode margin, A ₄ ...Connection part.

Claims (1)

[Claims] 1. In a capacitor in which a dielectric material having a metal vapor deposited electrode is wound and a metallicon is applied to the end face, the metal vapor deposited electrode near the metallicon scatters when the short circuit current between opposing different types of electrodes is greater than the self-healing function limit of the metal vapor deposited electrode. . A capacitor comprising two or more connecting portions that scatter at the same time as the metal vapor-deposited electrode near the metallicon scatters and insulate the electrode around the short-circuited portion from an adjacent electrode of the same type.