HU180137B - Bipolar electrolytic condenser - Google Patents

Abstract

The intention is to overcome the technical difficulties known in bipolar electrolytic capacitors, especially in alternating voltage operation, which are attributed to cathodic reaction processes on the respective negative-shaped electrode foil. According to the invention, an electrically floating unformed electrode foil is arranged between the formed electrode foils. In operation, this automatically adjusts itself to a small positive potential with respect to the respectively negative formed electrode foil, whereby at most a very small potential difference dU can occur between the negative electrode foil formed and the adjacent electrolyte boundary layers and disadvantageous cathodic reaction processes are avoided. The quality improvement achieved thereby makes it possible, for example in the case of motor-on-site electrolytic capacitors, to use cost-saving, highly roughened non-stabilized electrode films with a power-saving reinforced oxide layer instead of weakly roughened stabilized electrode films.

Description

The present invention relates to bipolar electrolytic capacitors having at least a film forming electrode foil and having terminals formed thereon.

In the known electrolytic capacitors, the dielectric consists of an oxide layer formed by the anodic oxidation of a so-called valve metal electrode film. Valve metals are aluminum, tantalum, titanium, and niobium, and this dielectric layer is also called a valve layer because it has a high resistance to reverse voltage at voltages below the so-called forming voltage at the electrolytic process. its resistance becomes low. During anodic oxidation, also known as shaping or preforming, the valve layer grows as long as the electric field strength measured through the valve layer remains high enough to maintain ion flow through it. In the case of aluminum, this minimum field strength is about 10 MV / cm. As soon as the valve layer reaches a thickness at which the minimum field strength does not exceed the actual field strength, the additional layer growth is completed and the relatively high forming current decreases to a much lower leakage current.

This leakage current is caused by minor imperfections in the valve layer, which are due to impurities present even in the purest valve metal available and the fact that the oxide layer is never completely insoluble in the forming electrolyte. Due to the dissolution of the oxide, also known as deformation process 1180.137, the field strength in the valve layer rises above the value of the minimum field strength and you can reshape a new oxide layer,

The process of deformingβ also occurs in electrolytic capacitors stored in a non-voltage state, especially at higher temperatures. However, even under operating conditions, at the operating voltage E, the deformation process takes place, and ^w the valve block is reshaped to a partial operating voltage E, so that deformation decreasing from the forming voltage E _{f to} the operating voltage E cannot be prevented. Let's play it.

Valve deformation! process results in significant degradation of the electrolytic capacitor in terms of electrical characteristics and useful life. Therefore, it is of great importance that we take every appropriate opportunity to prevent or minimize the deformation process.

From the above-mentioned shaping process, it becomes clear how the shaping stress at which the valve layer was formed can be determined. Of this kind, it is necessary to place the formed electrode film or a portion thereof in a suitable electrolyte using a counter electrode, and then apply a dc power to the system and gently increase it. For the voltages below the forming voltage E_, a low leakage current can be observed, whereas a much higher forming current is generated for the voltages above the forming voltage E_.

It is also known to specify a nominal voltage and an osuo or maximum voltage for electrolytic capacitors. These voltages are defined as the value of the DC voltage or the resulting peak value of the superimposed AC voltage that can be permanently applied to the capacitor / rated voltage or that parts can be connected to the capacitor for a short time and never t /. The partial voltage, together with the rated voltage, is printed on the capacitor or the manufacturer gives these values in the relevant technical specifications, and the partial voltage is usually 1.1 to 1.3 times the rated voltage.

For any nominal / operating voltage, it is known to use a dielectric valve layer formed with an E_ forming voltage of at least 1.05 times the partial voltage. For example, a 5 O / O V electrolytic capacitor is preformed at least 63 V, a 350/400 V capacitor at at least 420 V and a 500/550 V at at least 600 V. In this way, when the partial voltage is applied, further shaping is prevented, which further forming would result in a decrease in the value of the capacitance and / or in the failure of the capacitor. A safety margin of 5% or more is required to offset normal manufacturing tolerances,

According to this relationship between the nominal / oscillating voltage and the E. forming voltage, it is possible. optimizing the electrolytic capacitors for any partial voltage up to 600 V Since the thickness of the dielectric valve layer is proportional to the forming voltage E_, high capacitance values are generated at lower forming voltages and lower capacitance values at higher forming voltages.

-2180.137

A known method of making electrolytic capacitors is to coil the electrode foil foils with an oscillator (usually paper plane) made of absorber separators placed between them. The electrode film may be flat or having an increased surface, whereby surface enlargement can be achieved, for example, by etching. During etching, the specific capacity, i.e. the capacity per foil area, can be significantly increased, for example up to 50 times /, and the capacitance volume can be reduced accordingly, since the dielectric valve layer is formed on any surface. In accordance with different requirements for surface augmentation, electrode films with both slightly and greatly elevated surfaces are used in different applications. Electrolytic capacitors may be polarized or bipolar in their structural design. The polarized electrolytic capacitor consists of at least one formed and unboiled electrode foil, each of which has at least one terminal and is wrapped with absorbent separator foots placed between them. The capacitor thus coiled is then impregnated and enclosed in a suitable electrolyte. The housing is provided with at least two isolated terminals and the terminals are connected to the electrode foil terminals.

The shapeless electrode film is also generally made of valve metal, and this layer is coated with a thin oxide film as a result of air oxidation, acting as a valve layer having an equivalent forming voltage of less than 5 V, typically between 1 and 4 V. Therefore, polarized electrolytic capacitors can be operated with or without direct voltage, with or without superimposed AC voltage, while ensuring that the peak voltage of the resulting voltage is within the range of rated-wishbone voltage and that no reverse voltage is present. at a higher level.

A polarized electrolytic capacitor consisting of a plurality of parallel partial capacitors can be obtained by winding a plurality of formed electrode films together with a single common or a plurality of separate non-formed electrode films. Each of these electrode films must be provided with at least one terminal.

If the polarized electrolyte capacitors must be capable of frequent charging and discharging modes (for example, for use as flash capacitors), a single unformed electrode film having a specific capacitance C in accordance with the peak capacitances E of the rated voltage of the capacitor should be used. film capacity C, and this condition is described in ^p

expression.

Only then will the charges, which flow from the anode to the cathode, charge the unformed electrode foil to less than 5 volts when the external capacitor is discharged. In this way, the gradual formation of the form-formed electrode film and the loss of capacitance of the anodic-cathodic capacitive series circuit are avoided.

-3180.137

If this condition is met, the electrolytic capacitor is referred to as discharge resistant.

When operating at reverse voltages, bipolar electrolytic capacitors are used, whereby a second formed electrode film is used instead of the unboiled electrode film of the polarized electrolyte capacitors. Thereafter, the two formed electrode films, which are provided with terminals, are wound together and absorbent separator foils are placed between them. After impregnation of the capacitor coil, either of the two formed electrode films can be used as an orphan or cathode. In the case of anode / cathode / polarization, the valve layer operates in the direction of higher / lower / resistance.

When a bipolar electrolytic capacitor has the same or different forming voltages on the two main electrode films, the capacitor is called a reversible or semi-polarized capacitor. Reversible electrolytic capacitors are suitable for operation at reverse DC and / or AC voltage, and semi-polarized capacitors are capable of operating at asymmetric DC and / or AC voltage.

Alternating voltage electrolytic capacitors are widely used as motor operating capacitors and as inverter filter capacitors (loudspeaker systems) at constant loads up to 100 Vac. At higher voltages, electrolytic capacitors are preferably used for batch operation as a starter capacitor for motors,

For electrolytic capacitors designed for AC operation, the rated / low voltage values refer to the effective values. Accordingly, according to a well-known rule, in these capacitors, the valve layer is formed at a forming voltage E 'which is at least 1.05 times the peak value of the maximum voltage E.

Compared to static co-capacitors, electrolytic capacitors have the advantage of providing a greatly increased capacity / volume ratio at low cost. However, the disadvantages of electrolytic capacitors are relatively large Loss! their angle / and the high tangent value of the loss angle, tg Γ /, and this significantly limits the scope of capacitors, especially for AC applications.

An electrolytic capacitor can be regarded as a series switching of the capacitance C and the resistor R, where the resistor R is also called the equivalent series resistor, and the tangent to the loss angle of this impedance at frequency f is tg <f s R · 27Cf 'C.

Resistance R consists of several parts and can be approximated by the following formula;

with dielectric losses occurring, mig r and r correspond to the absorbent separator layers impregnated with the electrolyte and the etched pores / when using an etched electrode film / ohmic resistance.

In line with this, the capacitor designer, in particular when developing bipolar electrolytic capacitors for AC operation, attempts to use highly porous and absorbent separators, highly conductive electrolytes, and electrodes with a slightly increased surface area.

180,137 'films with wide pore cavities, so as not to lower the values of resistances r' and Vp, and to provide valve layers that cause reduced dielectric losses to reduce the value of rj.

In this regard, it should be noted that the electrode films are etched in acids or saline solutions. Λ The film is dried after rinsing and during this drying process the thin oxide layer mentioned above is formed during oxidation in air. This oxide wire can be reinforced by boiling the film in the purest deionized water, which results in a significant saving of about 50% in the amount of electricity required for molding and a significant increase in capacity. On the other hand, however, the dielectric losses in the valve layer increase. To save costs, reinforced oxide film electrode films are used for high voltage DC / 100V / DC electrolytic capacitors used for filtration purposes, while thin oxide film electrode films are used in low voltage / DC 100V / electrolyte capacitors.

When using the aforementioned electrode films for bipolar electrolytic capacitors, difficulties arise when using AC, especially at higher AC voltages, such as high AC starter capacitors. These difficulties may include instability of the capacity value, rapidly increasing loss angle during operation, overheating, c'eformation, breakage, and explosion. These difficulties are particularly significant for reinforced oxide electrode films.

Accordingly, attempts have been made to reduce the loss of the dielectric valve layer by using electrode films with ultra-thin oxide film layers, where such oxide layers are made by applying phosphates to the electrode film immediately after milling and rinsing, but prior to drying. containing solution. So treated electrode films are called stabilized,

Ellen Despite the cost-intensive use of stabilized electrode films without reinforced oxide film, bipolar electrolytic capacitors still have many disadvantages in terms of quality and economy, especially in AC applications such as motor starter capacitors.

It is therefore an object of the present invention to provide a structural improvement of bipolar electrolyte capacitors which, particularly in AC applications, exhibit the aforementioned drawbacks to such an extent that they allow the use of cost-saving high specific capacity unstabilized electrode films with reinforced oxide layers.

The present invention provides a bipolar electrolytic capacitor having at least two formed electrode films and having corresponding terminals, the capacitor comprising at least one additional unformed electrode film between the formed films which covers and shields one another and a series circuit. formed from formed-to-unformed electrode films, and the unformed electrode film is electrically free to move within the potential difference between the formed films.

-5180.137

The electrolytic serial circuit can be obtained by arranging the formed electrode films in a downstream or longitudinal direction relative to one another. In the transverse position, the formed electrode films are cross-aligned with two unformed electrode films and absorbent separators. In the longitudinal arrangement, the formed electrode films are sequentially wound and an unformed electrode film and absorbent separators are used which pass through the entire capacitor body. These alternative layouts will be described and explained in greater detail in the drawing.

In DC operation, the voltage-gated salt on the electrolyte capacitors occurs almost entirely on the valve layer of the positive formed electrode, which operates in the high resistance direction, while being voltage-gated across the conductive electrolyte and the low resistance direction of the negative formed / or unformed / electrode valve. Accordingly, the voltage drop between the negative electrode and its tight electrolyte layers will be very small and the cathodic reactions will not be affected. Azonban However, when charging and discharging a capacitor, and similarly in the case of a polarity reversal, the charge arithmetic causes a sufficiently high voltage drop across the electrolyte in series with sufficiently high operating voltages, and consequently between the negative electrode and its adjacent © lectrolyte layer. At a negative electrode, cathodic reactions are initiated and the properties of the valve layer are affected and gradually deteriorated.

In this regard, it is believed that the voltage drop between the negatively formed electrode foil and its adjacent electrolyte coils will be an ancestor even at higher operating voltages, since this drop will be sufficient to prevent the cathode causing the valve layer from being affected. the unformed electrode film may electrically migrate freely within the voltage drop region between the formed electrode films. If this unformed electrode film is made from my valve wood, no valve film is formed on it, but in accordance with the electrolytic polarization, the particles are charged to a very low positive potential. If the unformed film consists of a valve metal, it is always covered with a thin oxide layer at the bottom and acts as a valve film, although in the case of aluminum it corresponds to a forming voltage of 1-4 V and this layer is 1-4 V compared to the negative formed electrode film. can take up a positive potential not exceeding, if its electrical potential can float freely, that is, the unformed film is electrically unattached, The low / AE voltage drop between the unformed and the negatively formed electrode film, for example ΛΒ at 1-4 V / charge causes a very small drop in voltage between the negative formed electrode film and its adjacent electrolyte layers (dEZ Z: E /), and thus prevents dangerous cathodic reactions and deterioration of their valve layer properties,

The cathodic reaction at the unformed electrode film takes place just as it does with any polarized electrolyte capacitor. However, the deterioration of the properties of the valve layer is not harmful or even advantageous because the "unformed electrode"

With 180,137 f61i6 serial goods, it becomes even more tamper proof and its serial capacity is increased.

In addition, in the electrolytic capacitor of the present invention, the voltage drops Λ E and dE are further reduced, and the valve layer is further protected.

From the fact that under operating conditions the unformed electrode film is not formed, the specific capacitance C _o should be consistent with the maximum capacitor voltage i-aT'-t-nrr.AT? nm'in «f * a.« i * 7: íi 1 t ..4 / 5 · ρ · α1 and formoli: electrode trees Cp

It is related when the electrode film is made of valve metal.

In the first embodiment of the invention, it is unformed. electrode foil made of a material that is difficult to form; and

It contains less than 99.9%, preferably less than $ 99.5, of valve metal. In this case, it is assumed that the AC operating voltage is up to 10 V without any undesired formation.

It is preferable that the unformed electrode film be wider than the unformed electrode film to provide complete coverage and shielding of the formed electrode films with the unformed electrode during winding of the capacitor body, when lateral displacement of the film strips is never completely avoided. With improved shielding, increased capacitance output, reduced loss angle and improved thermal conductivity toward the ends of the coiled capacitor body were achieved.

Since the electrically free unstable electrode foil with fluctuating potential is never to be wired, it is advantageous that the foil is not provided with a terminal at all.

In a further embodiment of the invention, the electrolytic capacitor consists of at least three formed electrode films having leads and an unformed unformed electrode film. This embodiment allows the provision of at least two capacitor portions in a common capacitor coil, such as an additional Motor Motor Capacitor for continuous operation of a hub formed in a common capacitor coil, e.g.

In another embodiment of the invention, the electrolytic capacitor consists of a series circuit of two bipolar capacitor portions, each of which consists of a series of formed-unformed-formed electrode foils and is housed in the same capacitor coil and is insulated with one another, e.g. It is separated by a flexible thermoplastic layer, where the two capacitor portions form a serial circuit consisting of an unformed-formed-molded-formed-formed-electrode foil. This embodiment is particularly suitable as a motor start capacitor for high-voltage operation where the electrolyte having a sufficiently high voltage voltage would have too low conductivity and would result in poor capacitor characteristics and contribute to overheating.

In a particularly preferred embodiment of the invention developed for AC operation

The electrolytic capacitor 180,137 nz contains at least two formed electrode films and this embodiment is characterized in that the forming voltages Ef have a value at least legalább Ef 1.05 Ep relative to the partial voltage of the capacitor Ep in at least one direction, and is preferably a value for which so that 0.5 E „<2 Ef <. Ep. In other words, the electrolytic capacitor made in accordance with this embodiment of the invention is characterized by having a lowered, preferably significantly reduced, forming voltage Ef relative to known electrolytic capacitors of a given voltage.

Unexpectedly, it has been found that an electrolytic capacitor formed in accordance with this embodiment of the present invention and having at least one electrode foil formed with capacitor overvoltage at a shaping voltage Ef of less than E, the capacitor gradually did not build up to the peak voltage Ep corresponding to the overvoltage and did not fail, as would be expected by a suitably skilled and experienced technician.

In order to explain this surprising observation, it is assumed that during the formation, the ion flow through the valve layer is at a finite speed depending on the field strength. Based on this, it is understood that an additional increase in valve layer requires an increase in field strength, the value of which depends on a minimum duration, and short-term, limited voltage peaks are not able to induce gradual formation, even at low altitude. . For example, suppose that the shaping voltage is E _r = 0.85 E. At this point, the value of aro.sin.0.85 is 58.2 °, and at a frequency of 50 Hz, for a period of 20 ms, the forming voltage Ep is only exceeded by the current voltage for only 3.53 ms, which, in line with observations, proves that it is not yet sufficient. to trigger any further formation. Of course, appropriate measures must be taken to avoid excessively high DC voltages remaining when the AC component is suddenly turned off or the capacitor needs to be discharged rapidly, for example by a discharge resistor.

The experiments have also shown that the electrolytic capacitors made in accordance with this embodiment of the invention have a much higher stability under operating conditions than the known electrolytic capacitors. This observation can be explained by the assumption that the aforementioned nose is prevented by significantly lowering the forming voltage Ef to or below the operating voltage E _p .

Electrolytic capacitors made in accordance with this embodiment of the invention also have the advantage of preventing, on the one hand, deterioration of the properties of the valve layer on the negative formed electrode film and, on the other hand, preventing deformation of the valve layer on the positive formed electrode film. . In addition to the above technical advantages, this embodiment is also a source of significant economic advantage. For example, if the value of the forming voltage Ef from 1.05 E _{p to} 0.85 Ej, value-8-

180,137, which represents a 19% decrease, the additional capacity increase is 19%, and in addition, the porous structure results in etched electrode foil, for example a 25-30% increase resulting in a cost savings of 25-30% in the cost of the electrode foil and the separator and electrolyte. Since the applied forming energy increases rapidly with the increase of the forming voltage, in the above example the electricity consumption is reduced by 35-50% <, which saves the formulation due to the amount of chemicals used and the formation time reduced. as a result of the capacitance, the production time is also shortened and the volume of this type of electrolytic capacitor is leo shock.

In a semi-polarized version of this embodiment of the invention, the capacitor overvoltage has values of oscillations Epi and Ep2, and the electrolytic capacitor consists of a formed electrode foil, which is formed by an E1. formed with a forming voltage and includes another formed electrode film formed with a forming voltage Ef 2 'x 1.05 0p2.

In a further embodiment of the invention, the electrolytic capacitor comprises at least one formed electrode film which, prior to forming, is provided with a reinforced exterior film formed, for example, by boiling the electrode film in purely deionized water.

It has been found that the presence of a non-formed electrode film in the present invention greatly protects the valve film properties of the negatively formed electrode from degradation by replacing the low-capacity, low-capacity, stabilized electrode films with low-cost, high-capacity even for high-start motor start capacitors.

By utilizing the above advantages of the present invention, high-capacitance electrode films with reinforced oxide layers are used, and by lowering the forming voltage, it becomes possible to use bipolar electrolyte capacitors for alternating current operation, such as motor starter capacitors and capacitors, total cost reduction will be 60-70%.

Under certain conditions, when the AC capacitors are operated on alternating current, transient overvoltages are generated when the voltage is switched on and off, for example motor start capacitors, which can reach up to 10 times the operating voltage of the capacitor and consequently the operating life is sufficiently reduced. tken. However, the unformed electrode film used in accordance with the invention results in a significant increase in strain on the tin at higher frequencies.

Examination of known motor start capacitors showed that the capacitor loss was / tan f / 20-30% and that of the electrolytic capacitors of the invention was 70%, with the result that the transient its vibration becomes highly oscillatory, which entails a lifetime increase in reliability.

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The invention will now be described in more detail with reference to the drawings, in which: In the drawing it is

Figures 1, 2 and 7 illustrate corresponding capacitor coil designs, a

Figures 3, 4 are illustrative diagrams of the potential conditions, the

Figures 5, 6 show the electrodes and adjacent electrolyte layers, and finally

Figure 8 illustrates a capacitor coil according to the invention.

Reference is now made to Fig. 1, which schematically illustrates a capacitor coil assembly which is particularly suitable for illustrating the present invention. The formed electrode films 1 and 2 are provided with terminals 3 and 4, and the electrode films 1 and 2 are transverse to each other, separated by two unformed electrode films 7 and 7 'and 5,6 and 5 »8» absorbers. formed by separators, which are arranged in layers. The formed electrode films 1 and 2 are completely covered and shielded by the unformed electrode films 7 and 7 'placed between them. After the probe wire-like structure thus formed is wound in the direction of the arrow and then impregnated, the formed electrode films 1 and 2 are electrolytically combined into a series circuit consisting of a source-to-source-electrode source. Depending on which electrode film is considered, the serial circuit consists of 1-7-2 or 2-7 »-1 * electrode films. Unformed electrode films 7 and 7 'are not electrically wired and therefore have the potential to vary freely within the voltage difference between the formed electrode films 1 and 2 and therefore have a value that is self-adjusting to a low positive voltage of less than 10 V, e.g. It is between 1 and 2 V, which values are relative to the potential of the negative unformed electrode film. In this way, the potential difference between the negatively formed electrode film and its adjacent electrolyte layers is substantially reduced, thus preventing any deterioration of the valve layer properties due to cathodic reactions.

Fig. 2 schematically illustrates a simple construction according to the invention, the formed electrode foils 1 and 2 are sewn with the terminals 3 and 4 and are longitudinally spaced relative to one another and in the direction of the arrow / with one or more layers of absorbent separators 5 and 6 and unformed electrode foil 7, the latter electrode foil 7 will be located in the winding so as to completely cover and shield the formed electrode foils 1 and 2 and, after impregnation, 2 electrode foils are electrolytically combined into a serial circuit consisting of a formed-to-spun-formed electrode foil. The unformed electrode film 7 is not electrically wound and therefore its electrical potential can vary freely within the voltage drop determined by the potential difference between the formed electrode films 1 and 2 and, when applied, the potential of the electrode film 7 self-adjusts to a positive potenol up relative to the negative formed electrode film, and this low potential is for example between 1 and 4V.

180 137

Figures 3 and 4 illustrate a voltage drop across the electrode films during operation. In these figures, the film potential of the unformed electrode 7 is assumed to be zero,

In the case illustrated in Figure 3, terminal 3 is considered positive and terminal 4 is considered negative, the unformed electrode film 7 has a lower potential of less than + 10 V relative to the negative formed electrode film 2, which accordingly has a slight negative potential. unformed shielding with respect to 7 electrode films. The slight ΛΕ10 V drop in voltage between the 2 edges of the electrode films prevents any deterioration of the valve film properties of the negatively formed electrode film 2.

Figure 4 illustrates the voltage drop with opposite polarization. Now, the low voltage salt of AB 4 10 V is obtained between the electrode films 1 and 7, which prevents any deterioration of the valve * food properties of the negatively formed electrode film 1.

Figures 5 and 6 illustrate anions and cations in the electrolyte layers adjacent to the electrode films during operation.

In the case illustrated in Figure 5, it is assumed that electrode film 1 is positive and electrode film 2 is negative. The high voltage drop between the films of the electrodes 1 and 7 (which is in accordance with Figure 3 *) results in the re-forming of the anions entering the valve layer of the positively formed electrode film, where necessary. At this stage, therefore, the unformed electrode film 7 between the electrode films 1 and 7 is not obstructed by cathodic reactions due to the negative / cathode / and high voltage drop between them, which can affect and ruin the very thin valve layer of the unformed electrode film 7. properties. This is not disadvantageous, but it improves the serial circuit between the electrode films 1 and 7, in that it becomes more discharge resistant and at the same time increases its serial capacity. The small voltage drop occurring between the electrode films 2 and 7 (in accordance with FIG. value of AE Z. 10 V, results in a very low voltage drop between the negative formed electrode film 2 and its adjacent electrolyte layers dE Z_ Δ E, thus preventing the cathodic reactions and the inertial properties of the negative formed electrode film to fail. In this section between the electrode films 2 and 7, the unformed electrode film 7 has a positive / anode / low potential, which corresponds to electrolytic polarization if it is not made of valve metal, or its own voltage and specific capacity if made of valve metal, and the valve layer is then reshaped accordingly.

Figure 6 shows the same conditions for reverse polarity. Further explanation is unnecessary as it is the same as in Figure 5.

Figure 7 illustrates a condenser coil construction of the present invention in a simplified view having two capacitor sections. The formed electrode films 1, 2 and 8 are provided with terminals 3, 4 and 9 and are separated by one or more absorbent separator layers 5 and 6 and an unformed electrode film 7. In the direction of the arrow

After being wound up and then impregnated, the unformed electrode film 7 behaves and exhibits an effect similar to that of the formed electrode film as shown briefly in FIG. For example, the lake was filled with the same capacity of my electrode films 1 and 2. Between terminals 3 and 4, a motor start capacitor section is formed which is suitable for intermittent operation. The electrode foil 8 is assumed to have a lower capacity and may be formed by a smooth or lcis capacitance foil which can further reduce the loss angle in continuous operation. This capacitor solenoid is accessible between terminals 3 and 9, or 4 and 9, and the heat generated in this arrangement is capable of dissipating through the entire capacitor coil and can be discharged through the coil and the common capacitor casing without local overheating.

Fig. 8 shows a partially unrolled capacitor coil 10 which forms part of the electrolytic capacitor according to the invention. The terminals 3 and 4 are connected to the formed electrode films 1 and 2 (of which only the electrode film 2 is visible at the uncoiled end of the telcer). and the electrode films 1 and 2 are wound together with the absorbent separators 5 and 6 and the unformed electrode film 7 in accordance with Figure 2, and the unformed electrode film 7 integrates the structure electrolytically and, after impregnation, the formed electrode films 1 and 2 In accordance with Figure 2, they are integrated into a serial circuit consisting of electrodes foils 1-7-2. The impregnated capacitor coil 10 may be housed in a suitable housing having external outlets, and terminals 3 and 4 may be connected thereto,

The present invention will now be described in more detail in the following two examples, which relate to their bipolar electrolyte capacitors for AC operation, which may be electrolytic motor start capacitors, since they are particularly suitable for illustrating various advantageous features of the invention.

Example 1

AAF is a 360 V 110/140 VAC motor starter capacitor / film type where Ε = V 2 · 14θ = 198 V / 2035 of the electrode film was prepared by forming in that _f E = 150 V _fi = 0.76 E_ Two film sections of 6.93 olF were provided with terminals as shown in Figure 2 and wound together with absorbent paper separators and an unformed electrode film made of Kappa 204 film.

The capacitor coil is impregnated with an electrolyte * · needles that

100

20 ml of ε ml of ethylene glycolic boric acid in ammonia solution containing 25% by weight of ammonia and diammonium phosphate (_ ΗΡθ forg) were mixed and

These were included. : ----------------------------------- as long as they have a specific resistance at 80 ° C. I became 80 ohms /

After impregnation, the condenser coil was placed in a housing 80 mm long and 36 in diameter.

The type 2035 film is a highly surface-enhanced aluminum electrode film that is predominantly deionized in water prior to forming12

-12180.137 and then reinforced with a layer of oxide produced by AJLUMINUM-WAI.ZWERiaS STNGEN, NSK. This film type has not been suitable for the manufacture of high quality motor start capacitors as long as it is made in the prior art,

Λ Kappa type 204 film for polarized electrolytic capacitors, highly surface-mounted aluminum cathode film produced by BECROMAL Italy.

By placing an electrically free-moving potential unformed electrode film between the formed electrode films according to the invention, this prevents the formation of harmful cathodic reactions and any deterioration of the valve cavity in the negative formed electrode film, thereby providing economically enhanced capacitance. equipped with electrode films.

By feeding the forming voltage to the slats (27% of the known solutions in the present example), the deformation of the known capacitors was prevented and further significant cost savings were achieved.

The high quality level of the capacitors of the present example is illustrated by the following favorable life-time experimental results performed at the capacitor over-voltage.

Average of 10 samples C / uF tg i initial measurement 3'63 2.8 30,000 cycles after a pulse load of 5θ Ilz and 140 V effektlv find me 359 3.2

of which, after a duration of 1.2 seo, a break of 0 V for 1.2 minutes / 1.7% fill / 55 ° C ambient temperature.

Example 2

A tension motor 80 / uF V 220 / 275V V starter condenser / where E = V 2 '· 275 - 3θ9 ^v p / 2035-type film of the electrode film was prepared to Ε the shaping, ρ = 330 V = 0.85 Ep at forming voltage. Two 6.49 ow foil sockets in the '2. 1 through 2, and wrapped with absorbent paper separators and an unformed electrode foil made from Kappa 204 film, and encapsulated as in Example 1.

By placing the formed electrode films in accordance with the present invention with an electrically free-changing potential unformed electrode film, we prevented the formation of harmful cathodic reactions on the negative formed electrode film and prevented any further deterioration of the valve layer, Thus, it has been possible to use economically enhanced surface electrode films with reinforced oxide layers.

By lowering the forming voltage (by at least 19% in this example compared to known solutions),

-13i80 137 we achieved significant cost savings and also avoided the need to deform the capacitors for prayer.

The high quality standards of the capacitors prepared according to this example are shown by the following favorable lifetime test results, which were performed with 85% of the capacitor light voltage genes.

Average of 25 samples C / uF initial measurement 80.7 Average of 25 samples ^c .z ^{, r}

tg tg F '%

000 periods after a pulse load corresponding to 50 Hz and 234V effective output, of which

After 1.2 seo, there was a 1.2 perore 0 V break with /1.7 $ fill / 55 ° C ambient temperature.

3.0

The u solution for the manufacture of electrolyte motor start capacitors is already widespread, in which the capacitors are made of three formed electrode films, which form a series circuit of a braided-braided-braided electrode bundle. the difficulties arising from cathodic reactions are correspondingly reduced but not eliminated. To obtain a C capacity value for this design, a 16 C capacity molded electrode film and a 0.5 Ef forming voltage are required compared to a simple formatted-form electrode film having a 4 C drop-off and an Ep forming tension, ancestry is accordingly much cheaper to manufacture, though the capacity value at least doubles at 0.5p, However, this costly practice had to be continued prior to the invention, as there was no such solution. because with which the difficulties arising from the cathodic reactions could have been overcome.

From the above two examples illustrating the killing of the present invention, it is clear that the construction of the impregnated formed-formed electrode films and even the formed-formed-formed electrode films could easily be replaced by the formed-unformed-formed electrode film construction of the present invention. represents a solution and is operational in the entire voltage range within which sufficiently high conductivity electrolytes can be produced, that is, to a peak voltage of about 450 V.

Above this voltage, the serial circuit design of the formed-unformed-formed-formed-unformed-formed electrode foils, as described above, is still cheaper to produce than the formed-formed-formed electrode foil construction and prevents harmful cathodic reactions.

In particular, the invention has been described so far with the motor in

The invention is also applicable to other bipolar electrolytic capacitors. Accordingly, the present invention is not limited to any application.

It is believed that the disclosed embodiments are useful for capacitors having an operating voltage in the 150-400 V AC range, but particularly useful in motor starting areas. For such capacitors, it is preferred that the forming voltage be within the range 0.8-0.9 times the peak voltage E. ^p

Claims (13)

Patent claims A bipolar electrolytic capacitor having at least two formed electrode films with terminals ©, characterized in that at least one further unformed electrode film overlaps and shields each other between the formed electrode films (1,2) / 7,7 ', 8 / and the electrode films (1,2,7,7 », 8 /) together form a serial circuit consisting of a shaped-to-undrilled-source t electrode film, where the unformed electrode film / 7» 7 '> 8 / a has electrically floating potential within the voltage drop between the formed electrode films / 1,2 /. 2. Condenser according to claim 1, characterized in that at least one of the formed electrode films (1,2) is a hydrated electrode film with an increased surface area. An embodiment of a capacitor according to claim 1 or 2, characterized in that its operating voltage range is between 150 and 400 V AC, 4. The electrolytic capacitor according to any one of claims 1 to 3, wherein for alternating current operation, the sum of the forming voltages / Ep / a in the direction of at least one voltage is relative to the peak value of the maximum capacitor voltage / Ep / such that XE _f '1 And 05 E _n> preferably characterized in that the formed electrode films have / 1,2 / a. ¹ 6. A condenser according to any one of the preceding claims, characterized in that the formed film / 1,2 / is positioned one after the other on the same side of the unformed film / 7 /. An embodiment of an electrolytic capacitor according to any one of the preceding claims, characterized in that the specific capacitance of the unformed electrode film (7,7 '> 8) / C / to the peak value of the maximal voltage of the capacitor / Ep / and the specific electrode films formed. with respect to / C / satisfies the following condition: ^p 10V The electrolytic capacitor according to any one of the preceding claims, characterized in that the The -15160.137 electrode foil / 7,7 '»8 / is made of a hard-to-mold material and contains less than $ 99.99, preferably less than $ 99.5, 9. An electrolytic capacitor according to any one of the preceding claims, characterized in that it has a film of unformed electrode wider than the film of the formed electrode (1,2,7), 10. An embodiment of an electrolytic capacitor according to any one of the preceding claims, characterized in that the film of unformed electrode (7,7 ', 8) is provided without a terminal. 11. Embodiment of the electrolytic capacitor according to any one of the preceding claims, characterized in that at least three formed electrode films (1,2) are provided with one terminal (3,4), and at least one unformed electrode film without terminal. / 7 / yes, 12. The electrolytic capacitor of any one of claims 1-10, wherein the bipolar capacitor comprises a serial circuit formed by two parts, each of which consists of a "shaped-unformed-formed battery -> wire film serial circuit, and the portions being located in the same capacitor coil and separated from one another by a sheet of insulating material, and the two capacitor portions forming a serial circuit consisting of formed-unfiltered-hollow-formed-unformed-hollow electrode foils, 13. The electrolytic capacitor according to claim 13, characterized in that it has a semi-polarized structure, wherein the maximum capacitor voltages have different partial voltages / E. , E / / are evaluated where, for the formed electrode films / 1.2% of the forming voltages satisfy the following equations: E ^. 1.05 E and 1.05 _o ^x E_ ^Ep 2 ', ^P 14. Electrolytic capacitor according to any one of the preceding claims, characterized in that at least one formed electrode film has a reinforced oxide layer (1,2) formed by boiling the electrode film in purely deionized water.