JPH0469806B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to an electrolytic capacitor, specifically an electrolytic capacitor in which a capacitor element having a lead wire is impregnated with an electrolytic solution and a synthetic resin outer shell is formed via a resin tape. The present invention relates to a capacitor and a manufacturing method thereof.

(Prior Art) The above-mentioned electrolytic capacitor was disclosed in Japanese Patent Publication No. 46536/1989 filed by the applicant of the present invention.

According to the application, the following steps were exemplified in the description of the examples for the method of manufacturing the capacitor.

a' A capacitor element is formed by alternately overlapping two electrode foil tapes and an insulating tape, and winding them around a winding shaft with both the negative and negative lead wires connected to the electrode foil tapes. A winding process in which a wide resin tape is wound, b' a crushing process in which the capacitor element removed from the winding shaft is crushed to form a flat shape, c' a capacitor element is immersed in an electrolyte bath to be impregnated with electrolyte. an impregnation step, d' a preliminary aging step, e' a first sealing step of heat-sealing and sealing the resin tape opening on the head side of the capacitor element, f' applying powder to the resin tape opening on the base side of the capacitor element. a second sealing step of filling and curing synthetic resin and sealing; g' an outer shell forming step of forming a synthetic resin outer shell around the outer periphery of the resin tape;

Note that the crushing step b' may be performed after the impregnating step c'.

(Problems to be Solved by the Invention) According to the above-mentioned conventional method, the capacitor element is formed into a flat shape by the crushing step b', and there are the following problems.

Since the capacitor element is crushed, there is less space inside the element, and the internal pressure of the element increases due to gas generation and volumetric expansion of the electrolyte, causing liquid and gas leaks and shortening the life of the capacitor.

In other words, the electrolyte expands in volume (approximately 10% at 85°C) as the temperature rises and generates gas, and gas is also generated over time, which causes the base side sealing to increase due to the increase in internal pressure of the element. The leakage occurs through minute gaps in the capacitor, causing an increase in the dielectric loss angle (tan δ) and leakage current (LC) of the capacitor, resulting in decreased performance and shortened durability.

The crushing process may loosen the contact between the electrode foil tape and the lead wire terminal, or cause the electrode foil tape to crack or break due to the terminal, resulting in poor contact, corrosion due to galvanic corrosion, and dielectric loss angle ( tan δ) and leakage current (LC), or may cause wire breakage or shoots, which may also cause problems such as reduced reliability and durability.

Further, according to the above conventional method, the second sealing step f' is performed after the impregnating step c'.

Therefore, in the impregnation step c', the electrolyte is attached to the capacitor element, the resin tape, and the lead wires, and in this state, the powder synthetic resin is filled in the second sealing step f', so that the resin, the element, the lead wires, etc. Poor adhesion and poor sealing properties may cause liquid or gas leaks. Further, since the electrolyte is also attached to the outer periphery of the resin tape, the adhesion of the resin in the outer shell forming step g' is also reduced.

The present invention eliminates such conventional problems and improves reliability and
The purpose is to provide electrolytic capacitors with excellent performance and durability.

(Technical means for solving the problem) The manufacturing method of the present invention is as follows: a. Two electrode foil tapes and an insulating tape are alternately overlapped, and both the negative and negative lead wires are connected to the electrode foil tape. A winding process in which a capacitor element is formed by winding it around a winding shaft, and then a resin tape wider than the above-mentioned tapes is wound around the outer circumference of the capacitor element, b. a first sealing step of filling and curing synthetic resin and sealing; c. an impregnation step of injecting and impregnating an electrolyte into the capacitor element using a syringe through the resin tape opening on the head side of the capacitor element; d) a preliminary aging step; e. A second sealing step of sealing the resin tape opening on the head side of the capacitor element; f. An outer shell molding step of forming a synthetic resin outer shell around the outer periphery of the resin tape.

In other words, the manufacturing method of the present invention, compared to the conventional method,
The crushing process b' is eliminated, the sealing process b on the base side in which the powdered synthetic resin is filled and hardened is carried out before the impregnation process c, and the capacitor element is impregnated with the electrolytic solution using a syringe in the impregnation process c. It is characterized by this.

(Function) By eliminating the above-mentioned crushing step b', a round capacitor element is formed with a cavity left in the part where the winding shaft is removed, increasing the space inside the element, and the relationship between steps b and c is The filling operation with the powdered synthetic resin is performed in an unimpregnated state where the element and the resin tape are not attached to the electrolyte.

Further, by using a syringe in the impregnation step c, the electrolytic solution does not adhere to the outer periphery of the resin tape.

(Example) Embodiments of the present invention will be described with reference to the drawings.

a Winding process (Figures 1 and 2) Capacitor element A uses two conductive electrode foil tapes 1, 1' and two insulating paper tapes 2, 2'. The electrode foil tapes 1', 2, 2' are alternately wound in the order of 1, 2, 1', 2', and the lead wires 3, 2' are wound on top of each other in the order of 1', 2, 2'.
Insert the terminal 4 of 3' in a connected manner.

The electrode foil tapes 1, 1' are the anode foil tape 1,
The cathode foil tape 1' is an aluminum foil whose surface has been surface-treated by etching, and the paper tapes 2 and 2' are permeable thin strips of paper.

The lead wires 3 and 3' are each made by welding an aluminum wire terminal 4 to one end of the wire, and welding the aluminum wire terminal 4 to the terminal 4.
The tip of the electrode foil tape is crushed into a flat shape, and the tip is caulked to the electrode foil tapes 1 and 1'.

Both tapes 1, 1', 2, 2' are wound simultaneously by the winding shaft 5, and a roll-shaped capacitor element A is formed and the lead wires 3, 3' are pulled out.

At this time, the electrode foil tapes 1, 1' are wound with a slight shift so that the lead wires 3, 3' do not overlap.

Next, the tapes 1, 1',
A resin tape 6 wider than 2 and 2' is wound.

The resin tape 6 is a transparent film tape coated with adhesive on one side, and is wound so as to cover the outermost circumference of the capacitor element A. It isolates the outer peripheral surface of the element A from the outside and at the same time stops the wound outer end of the element A. I'm wearing it.

After the winding process a is completed, the capacitor element A
is removed from the winding shaft 5, the electrode foils 1 and 1' are inspected for short circuits, and the non-defective products are transferred to the next process.

Capacitor element A formed in the above rolling process a
A cylindrical cavity 10, which remains after the winding shaft 5 is removed, is formed in the center, and a resin tape 6 has a cylindrical opening protruding from the base side (lead wire side) and the head side of the other end of the element A. (3rd
Fig. 4).

b First sealing step (Fig. 5) The opening 6' of the resin tape 6 protruding from the base side of the capacitor element A is filled with powdered synthetic resin such as epoxy resin, and the element A is heated to seal the resin. is thermally cured to form a sealing wall 7, thereby sealing the opening 6'.

c Impregnation process (Figure 6) Element A that has gone through the previous process b is turned upside down, and injector B
Electrolytic solution (paste) B' is injected through the head-side opening 6'' of the resin tape 6 to impregnate the paper tapes 2 and 2' of the element A.

d Preliminary aging process (Figure 7) Lead wires 3 and 3' are energized and aged.
At this time, gas generated within the element A due to heat generation flows out from the opening 6''.

e. Second sealing step (FIG. 8) After preliminary aging, the head side opening 6'' of the resin tape 6 is sealed by heat fusing.

f Outer shell molding process (Figures 9 and 10) First, a photocurable resin (UV resin) is applied to the capacitor element A that has gone through the previous process e to form an inner layer 8', and then epoxy or polyester is applied. A liquid thermosetting resin such as ester resin is applied and the resin is heated and cured to form the outer layer 8.

Through the above steps, capacitor A is molded. After aging again, capacitor A is inspected for internal short circuits, standards are printed on the outer surface of outer layer 8, and after drying, various characteristics of the capacitor (leakage current , dielectric loss, and capacitance) and sort them into good and defective products.

(Effects) According to the present invention, since a cylindrical cavity is formed at the center of the element, the internal space that absorbs the volumetric expansion of the electrolytic solution and gas generation increases, and the internal pressure of the element is reduced. increase can be suppressed. In addition, separation of the electrode foil tape from the lead wire terminal and cracks and damage to the electrode foil tape can be minimized.

Furthermore, since the base side of the capacitor element is filled with powdered synthetic resin and sealed without being impregnated with electrolyte, it is possible to improve the adhesion between the resin and the element, etc., and improve the sealing performance of the sealing part.

In addition, since the synthetic resin outer shell is formed with no electrolyte attached to the outer periphery of the resin tape, the resin has good adhesion to the resin tape and the sealing part, resulting in a strong outer shell structure with excellent sealing properties. It can be done.

Therefore, the reliability, performance and durability of the electrolytic capacitor can be improved, and the intended purpose can be achieved.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the winding up of the element tape in the winding process of the manufacturing method of the present invention, Fig. 2 is a perspective view showing the winding up of the resin tape in the same process, and Fig. 3 is the winding up process. A vertical cross-sectional view of the completed capacitor element, Figure 4 is a cross-sectional view taken along the - line, and Figure 5 is a vertical cross-sectional view of the completed capacitor element.
Vertical cross-sectional view of the capacitor element after the sealing process, No. 6
Figure 7 is a vertical cross-sectional view showing the impregnation process, Figure 7 is a vertical cross-sectional view showing the preliminary aging process, Figure 8 is a vertical cross-sectional view showing the second sealing process, and Figure 9 is a vertical cross-sectional view showing the capacitor element after the shell forming process. The vertical cross-sectional view, Figure 10, shows the x-
It is an x-ray cross-sectional view. In the figure, A is a capacitor element, B is an injector,
B' is electrolyte, 1, 1' is electrode foil tape, 2, 2'
is paper tape, 3, 3' are lead wires, 4 is terminal, 5
is the winding shaft, 6 is the resin tape, 6' is the opening on the base side,
6″ is the head side opening, 7 is the sealing wall, 8 is the outer cover,
8' is an inner layer cover, and 10 is a cavity.

Claims (1)

[Scope of Claims] 1. A method for manufacturing an electrolytic capacitor in which a capacitor element having a lead wire is impregnated with an electrolyte and an outer shell made of synthetic resin is formed via a resin tape, comprising: a. two electrode foil tapes; and insulating tapes are alternately overlapped, and both the insulating and yang lead wires are connected to the electrode tape and wound around a winding shaft to form a capacitor element, and then a resin tape wider than both tapes is wound around the outer circumference of the capacitor element. b. A first sealing step of filling and curing powdered synthetic resin into the opening of the resin tape on the base side of the capacitor element removed from the winding shaft; c. A resin tape opening on the head side of the capacitor element. an impregnating step of injecting and impregnating the capacitor element with an electrolytic solution using a syringe; d) a preliminary aging step; e) a second sealing step of sealing the opening of the resin tape on the head side of the capacitor element; A method for manufacturing an electrolytic capacitor, comprising: an outer shell molding process for forming a resin outer shell.