JPH04267514A - Manufacture of electrolytic capacitor - Google Patents

Abstract

PURPOSE:To enhance the reliability on products by devising the manufacturing method capable of avoiding the shortcircuit of the title electrolytic capacitor during the application. CONSTITUTION:The shortcircuit inspection process P4 is interposed between the winding process P3 winding anode foil and cathode foil holding a separating paper and the electrolyte impregnating process P5 impregnating the intermediate element of the title electrolytic capacitor manufactured in the winding process P3 with an electrolyte so that the shortcircuit inspection process P4 may be performed before the performance of the impregnating process P5 with the electrolyte.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a so-called foil-type electrolytic capacitor in which an anode foil and a cathode foil are wound up with a separator paper in between, and the separator paper is impregnated with an electrolyte.

0002

[Prior Art] Conventionally, this type of electrolytic capacitor has been manufactured by etching a metal foil made of aluminum to increase the surface area to 10 to several tens of times the apparent area, and then anodizing it to form an oxide film on the surface. Next, a separator paper is sandwiched between this anode foil and a cathode foil that does not have an oxide film, and the separator paper is rolled up.The separator paper is then impregnated with an electrolyte solution.Finally, this electrolyte solution is It is manufactured by enclosing the impregnated element in a case.

[0003] Further, the manufactured electrolytic capacitor is subjected to aging in order to stabilize the electrical characteristics of the element, and after that, the characteristics are inspected before being shipped as a product.

0004

[Problems to be Solved by the Invention] However, among the conventional electrolytic capacitors manufactured and shipped in this manner, some may temporarily short circuit during use, even though characteristics are tested before shipping. This occurs because metal powder generated from the anode or cathode is rolled into the element during the winding process, and the metal powder moves due to mechanical shock or the like after the product is completed.

The present invention was made in view of these problems, and its object is to prevent electrolytic capacitors from being short-circuited after the product is completed.

[0006]

[Means for Solving the Problems] That is, the present invention, which has been made to achieve the above object, consists of an anode foil having an oxide film formed on its surface and a cathode foil having no oxide film formed on its surface, with a separating paper placed between them. A winding process of sandwiching and winding, an impregnation process of impregnating the intermediate element produced in the winding process with an electrolyte, and an assembly of enclosing the intermediate element impregnated with the electrolyte in the impregnation process in a case. The method for manufacturing an electrolytic capacitor includes the step of applying a DC voltage to the intermediate element to inspect a short-circuit state between the anode foil and the cathode foil before the impregnation step.

[0007]

[Operation] In this way, in the present invention, after winding up an anode foil and a cathode foil with a separator paper in between, a short circuit test is performed on the intermediate element produced in the winding process, and then the intermediate element is inspected for short circuits. Impregnated with electrolyte and sealed in a case.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Examples of the present invention will be described below with reference to the drawings. First, FIG. 1 is an explanatory diagram showing the manufacturing process of an aluminum electrolytic capacitor according to an embodiment.

As shown in the figure, in this example, first, in the anode processing step P1, an Al foil (anode foil) whose surface area has been enlarged by etching and an oxide film (Al2O3) formed on the surface by anodization is used. At the same time, in the cathode processing step P2, the electrode piece for drawing out the anode is crimped and crimped, and the electrode piece for drawing out the cathode is attached to Al foil (cathode foil) that does not have an oxide film and whose surface area has been expanded by etching. After crimping and crimping, in a winding step P3, using a well-known winding device, the anode foil and cathode foil obtained in the above steps P1 and P2 are rolled up with a separator paper in between, Fabricate an intermediate element.

[0010] After the intermediate element is manufactured in the winding process P3 in this way, the intermediate element is inspected for short circuits in a short-circuit inspection process P4 using a test circuit to be described later, and then in the winding process P3. The produced intermediate elements are classified into non-defective products and defective products. Next, an electrolyte impregnation step P5 is performed in which the isolation paper of the intermediate element identified as a good product in the short circuit inspection step P4 is impregnated with an electrolyte solution, and then in an assembly step P6,
The intermediate element impregnated with an electrolytic solution is enclosed in a cylindrical Al case with each of the electrode pieces pulled out.

[0011] When the electrolytic capacitor is manufactured in this way,
Next, in the aging step P7, aging is performed in which the electrolytic capacitor is continuously operated for a predetermined period of time (for example, 1 to 2 hours) or more by applying a voltage between the rated voltage and the surge voltage in a constant temperature layer (for example, 70 to 85 ° C.). Let's do it. When this aging step P7 is completed, in a product inspection step P8, various tests are performed to check the short-circuit state, capacity, etc. of the electrolytic capacitor, and electrolytic capacitors that meet predetermined standards are selected. And finally, taping step P9
At step P8, the Al case of the electrolytic capacitor that satisfies the predetermined standards selected at the product inspection step P8 is taped to complete the product of the electrolytic capacitor.

Next, FIG. 2 is an electric circuit diagram showing the configuration of a test circuit used to test intermediate elements for short circuits in the short circuit test step P4. As shown in the figure, this test circuit includes a voltage application circuit 3 that applies a DC voltage to the intermediate element Cx, and an anode of the intermediate element Cx (y shown in the figure) when voltage is applied.
point) and the potential of the cathode (point x shown in Figure 2), the intermediate element Cx
and a short circuit detection circuit 5 for detecting a short circuit.

First, the voltage application circuit 3 includes a switching circuit 7 that is turned on for a predetermined time T in response to an external application command, and when the switching circuit 7 is turned on,
The DC voltage from the DC power source 9 is applied to a charging resistor R2 and a detection resistor R connected to the anode and cathode of the intermediate element Cx, respectively.
3 to the intermediate element Cx. Furthermore, a discharge resistor R1 is provided at the anode of the intermediate element Cx to discharge the charge accumulated in the intermediate element Cx when the switching circuit 7 is switched from on to off.

In the voltage application circuit 3 configured as described above, the switching circuit 7 is in the on state (period T from time t1 to time t4 shown in FIG. 3) depending on the state of the intermediate element Cx. The potentials of the anode and cathode of the intermediate element Cx, ie, the potentials at the x point and the y point, change as shown in FIG.

That is, first, when the intermediate element Cx is a good product, the switching circuit 7 is turned on, and immediately after a DC voltage is applied to the intermediate element Cx, a current temporarily flows through the intermediate element Cx, and x Although the potential at the point momentarily becomes positive,
Thereafter, the potential becomes 0 and becomes stable, and conversely, the potential at point y becomes stable at a predetermined voltage divided by the charging resistor R2 and the discharging resistor R1.

On the other hand, if the intermediate element Cx is a completely short-circuited product, the intermediate element Cx has a charging resistor R.
Since a predetermined current determined by the resistance values of 2, the discharge resistor R1, and the detection resistor R3 flows, the potentials at points x and y are approximately the same potential, and the potential at point x is much lower than in the case of a good product. The potential at point y is much lower than that of a good product.

Furthermore, a short circuit in the intermediate element Cx is caused by metal powder generated from the anode or cathode being drawn into the element during the winding process. In addition to complete short-circuits, there are pseudo-short-circuits that become short-circuited when voltage is applied and then return to a non-defective state, and pseudo-short-circuits that normally operate normally but temporarily become short-circuited due to vibration or the like.

In the case where the intermediate element Cx is the former pseudo-short circuit product 1 that causes a pseudo short circuit, the switching circuit 7
When turned on, the potentials at point x and point y respectively initially change in the same way as for a short-circuited product, and then return from the short-circuited state (at time t2
) after which the product will be in good condition.

Furthermore, in the case where the intermediate element Cx is a pseudo short circuit product 2 that causes the latter pseudo short circuit, when the switching circuit 7 is turned on, the potentials at the x point and the y point are normally the same as in a non-defective product. and at the time of short circuit (time t3), temporarily x
The potential at the point increases and the potential at the y point decreases.

[0020] The short circuit detection circuit 5
This detects short circuits based on the potentials at points x and y. As shown in FIG.

[0021] Here, these two comparators IC1, I
Among C2, one comparator IC1 is connected to the voltage application circuit 3.
This is to detect the pseudo-short circuit product 2 of the intermediate element Cx from the potential at the y point of
A voltage application circuit is connected to a resistor R4 for applying B, and is grounded through resistors R5 and R6, and further connected to a connection point between resistors R5 and R6. 3, and its inverting input terminal - is connected to a variable resistor V that divides the power supply voltage +B.
A reference voltage V10 is applied via R1.

That is, in the short circuit detection circuit 5, if the voltage at the non-inverting input terminal + of the comparator IC1 is constant, the power supply voltage +B is connected to the resistor R4 and the resistor R5.
and R6, resulting in a constant voltage V11, which temporarily increases when the potential at point y rises and temporarily decreases when the potential at point y falls, and is made to rise temporarily when the potential at point y falls.
By adjusting the resistance value of 1 and setting the voltage (reference voltage) V10 applied to the inverting input terminal - to a value slightly lower than the constant voltage V11, it is possible to For example, the output potential of the comparator IC1 is configured to temporarily become a Low level only when the intermediate element Cx connected to the voltage application circuit 3 is a pseudo-short circuit product 2 when the switching circuit 7 is turned on.

Next, the comparator IC2 is for detecting short-circuited products and pseudo-shorted products 1 of the intermediate element Cx from the potential at point x of the voltage application circuit 3, and its non-inverting input terminal + has the power supply voltage +B A reference voltage V20 is applied through a variable resistor VR2 that divides the voltage, and its inverting input terminal -
is connected to point x of the voltage application circuit 3 via a resistor R7. In other words, by adjusting the resistance value of the variable resistor VR2, the applied voltage (reference voltage) V20 to the non-inverting input terminal + of the comparator IC2 is set at the x point when the x point and the y point of the voltage application circuit 3 are short-circuited. By setting the potential to a value slightly smaller than the potential of the comparator IC2, the output potential of the comparator IC2 is set only when the intermediate element Cx connected to the voltage application circuit 3 is a short-circuited product or a pseudo-shorted product 1 when the switching circuit 7 is turned on. is configured to be at a low level.

Next, the RS flip-flop 11 is reset when a low-level reset signal is input to the reset terminal R, and is set when a low-level signal is input to the set terminal S, so that the RS flip-flop 11 outputs the output terminal Q. It is a so-called inverted input type in which the level of
The output terminals of No. 2 and 2 are connected, and power supply voltage +B is applied via resistor R8.

Therefore, in the test circuit of this embodiment, first, the intermediate element Cx to be tested is connected to the x and y points of the voltage application circuit 3, and then a low level reset is applied to the reset terminal R of the RS flip-flop 11. By inputting a signal to reset the RS flip-flop 11 and activate the switching circuit 7, short circuits and pseudo short circuits in the intermediate element Cx can be easily inspected.

In other words, if the intermediate element Cx connected to the voltage application circuit 3 is of good quality, each comparator IC1, IC2
Since the output of the RS flip-flop 11 remains at High level, the RS flip-flop 11 is not set and its output remains at Low level. However, the intermediate element Cx is a pseudo short circuit product 2
If so, the output of comparator IC1 will be low level, and if intermediate element Cx is a short-circuited product or pseudo-shorted product 1, the output of comparator IC2 will be low level. Therefore, if there is any short-circuit abnormality in intermediate element Cx, the RS flip-flop The flip-flop 11 is always set, and the RS flip-flop 11 outputs a high level detection signal. Therefore, if the detection signal output from the RS flip-flop 11 is used to indicate whether the intermediate element Cx is good or bad, short-circuit inspection after winding the intermediate element Cx can be easily and reliably performed. .

As explained above, according to the method for manufacturing an electrolytic capacitor of this embodiment, a short circuit inspection step P4 is inserted between the winding step P3 and the electrolyte impregnation step P5, and an intermediate test is performed before the electrolyte impregnation. Since the element is inspected for short circuits, it is possible to prevent intermediate elements that become defective or are likely to become defective after the product is completed from flowing into the electrolyte impregnation step P5 and subsequent steps. Product reliability can be improved, and waste during manufacturing electrolytic capacitors can be eliminated.

[0028] Furthermore, since the short-circuit test is performed at the stage of the intermediate element, especially before impregnation with the electrolytic solution, it is possible to easily detect not only short-circuited products but also pseudo-short-circuited products, thereby simplifying the inspection process. Can be done. In other words, when performing short-circuit inspection after being impregnated with electrolyte, it is difficult to detect instantaneous short-circuits like pseudo-short circuit product 2 because the leakage current of the element is increased by the electrolyte. Although a highly accurate measuring device is required, in this embodiment, the short circuit test is performed before impregnation with the electrolytic solution, so the short circuit test can be performed using a simple circuit, and the detection accuracy is also high.

Furthermore, in the inspection after the product is completed, since the device is enclosed in a case, it is not possible to directly apply an external force to the device, and therefore it is difficult to detect a pseudo short circuit. Since short-circuit inspection is performed in stages, external force can be applied directly to the element during this inspection, and pseudo-short circuit products can be detected more reliably.

In the above embodiment, a method for manufacturing an aluminum electrolytic capacitor has been described, but the present invention can be applied to any foil-type electrolytic capacitor manufactured by rolling an anode foil and a cathode foil.

[0031]

[Effects of the Invention] As described in detail above, according to the method of manufacturing an electrolytic capacitor of the present invention, since the intermediate element is inspected for short circuits before impregnating the intermediate element with an electrolytic solution, there is no possibility that the product will be defective or defective after the product is completed. can prevent intermediate elements that are likely to become defective from flowing into processes after the electrolyte impregnation process, improving product reliability and reducing waste during electrolytic capacitor manufacturing. . In addition, since the intermediate element is inspected for short circuits before being impregnated with the electrolytic solution, short circuit inspections on the intermediate element can be carried out using a simple electrical circuit, and short circuits and pseudo-short circuits in the intermediate elements can be detected with high accuracy. .

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing the manufacturing process of an electrolytic capacitor according to an example.

FIG. 2 is an electric circuit diagram showing a test circuit used in the short circuit test process of the embodiment.

FIG. 3 is a time chart illustrating potential changes at points x and y in the voltage application circuit of the embodiment.

[Explanation of symbols]

P1...Anode processing process P2...Cathode processing process
P3... Winding process P4... Short circuit inspection process P5... Electrolyte impregnation process P6... Post-assembly process P7... Aging process P8... Product inspection process
P9...Taping process 3...Voltage application circuit 5...Short circuit detection circuit 7
...Switching circuit 9...DC power supply 11...RS flip-flop
C1...Capacitor Cx...Intermediate element IC1, IC2...Comparator R1~R8...Resistor VR1, VR2...Variable resistor

Claims (1)

[Claims] [Claim 1] A winding process in which an anode foil with an oxide film formed on its surface and a cathode foil without an oxide film on its surface are rolled up with a separator paper in between, and the product produced in the winding process. In a method for manufacturing an electrolytic capacitor, the method includes an impregnation step of impregnating an intermediate element with an electrolytic solution, and an assembly step of enclosing the intermediate element impregnated with the electrolyte in the impregnation step in a case, in which, before the impregnation step, A method for manufacturing an electrolytic capacitor, characterized in that a DC voltage is applied to the intermediate element to test for a short circuit between an anode foil and a cathode foil.