DE2251404A1 - OPERATING ELECTROLYTE FOR ELECTROLYTE CAPACITORS - Google Patents

Description

225U04

SIEMENS AKTIENGESEILSCHAFT 8 Munich 2 19th OK1197

Berlin and Munich Wittelsbacherplatz 2

TPA 72 / 1Ϊ85

Operating electrolyte for electrolytic capacitors .

The invention relates to an operating electrolyte for an electrolytic capacitor en.

An oxidized aluminum foil is used as the anode in electrolytic capacitors used, whereby the O.Kid layer acts as a dielectric. The film is usually made up of -mlb paper interlayers processed into a winding, and this winding body is then impregnated with an operating electrolyte. The interactions of the operating electrolyte with the anode and with the Aluminum cathodes determine, among other things, the electrical properties and service life of the rj electrolytic capacitor. Included does the operating voltage of an electrolytic capacitor depend on the forming voltage? so from .the tension, with which the aluminum anode was preformed, as well as the Spark voltage of the operating electrolyte. Spark voltage is understood here to mean the voltage that occurs during the formation of a bare, not preformed aluminum anode in the relevant Electrolyte can be reached maximally.

To improve the oxide layer applied during preforming, it is reformed, the capacitor body in general is built into a housing. During the reforming process, gas is generated inside the electrolytic capacitor one, whereby the amount of gas evolved depends to a large extent on the type of operating electrolyte used is.

VPA 9/140/2031

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409619/0414

2 2 b 1 4 O 4

The object of the present invention is to produce operating electrolytes which are used when reforming the electrolytic capacitors small amounts of gas develop and during the further operation of the capacitors-the electrical properties favorably influence.

Operating electrolytes to which the invention relates are the following:

1. High-voltage (HV) operating electrolytes that contain approx. 5 mol H ₅ BO ₃ , 9-11 mol glycol »approx. 1 mol RH ₃ approx. 0.04-0.07 mol H ₅ PO ₄ and approx Contains 0.4 moles of mannitol.

2. Low-voltage (NV) operating electrolytes that contain 1 - 2 mol of H ₅ BO ₅ , 13 - 15 mol of glycol, approx. 1 mol of KOH and 0.01 - 0.03 mol of H ₅ PO per kg of electrolyte. contain.

3. Low temperature (TT) - operating electrolytes, which for example are composed of salicylic acid, diethylamine, glycol and dimethylformamide (DMF) as solvents, and which contain a small amount of phosphoric acid.

Such operating electrolytes are well known.

The object is achieved according to the invention in that per se known high-voltage, low-voltage or "low-temperature operating electrolytes Dodecyl phosphate in concentrations of 0.01 up to 2 percent by weight based on the total amount Electrolyte is added.

This has the advantage that the electrolytic capacitors, which contain the operating electrolyte according to the invention, use about $ 20 less charge during refurbishing as comparison capacitors with conventional operating electrical

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lyten. For example, "the charge consumption was one Electrolytic capacitor (1000 / uF; 63 V) with a low-voltage electrolyte, 2.9-C were added to the 0.05 percent by weight of dodecyl phosphate, compared with a charge consumption of 3.5 C in the case of a matching electrolytic capacitor without added dodecyl phosphate. This is due to the higher forming efficiency of the operating electrolyte according to the invention. The higher formation efficiency has the consequence that an electrolytic capacitor in the reforming on a certain Voltage less energy, which is converted into heat, has to be supplied. This also gets the undesirable Gas development .reduced. Additional cooling measures can be dispensed with.

An additional part of the gate is that even with small additions von Dodeeylphösphat to the known operating electrolytes the Spark voltage is increased significantly.

The figure shows the spark voltage U ™ a low-voltage industrial electrolyte as a function of m Dodecylphosphatzusätzen. Measurements were made at 30 ⁰ C on a smooth, unformed aluminum foil at a current density -from 1 mA / cm performed. "As can be seen from the figure, the spark voltage can be increased significantly by adding small amounts of dodecylphosphate.

TJm is the spark voltage of a low-temperature operating electrolyte which contains dimethylformamide (DMF) as an organic solvent is an addition of approximately 2 percent by weight Dodecylphosphate required. This increases the spark voltage of the electrolytic capacitor from 120 to 180 V.

On the basis of long-term test results, electrolytic capacitors with the operating electrolyte according to the invention and electrolytic capacitors with the known operating electrolytes were compared. The result of the storage test (tension-free storage at 85 ° C. for 100 hours) is given in Table 1 below. Capacity C, loss factor tgß, impedance Z and residual current I ^ (measured 1 min after application of the nominal voltage) were determined. 409819/041 4
YPA 9 / UO / 2O31. -4-

Table 1

electrolyte Nominal
span
tion Output values C.
■ uF tg cT Z
at
1OkHz
_n ¹ row
/ UA Values after
search tgcf
* Permanent ¹ row
/ UA KV electrolyte V 1098 3.4 0.046 50 C.
yUl ¹ 2.7 Z
at
1OkHz 228 NiV electrolyte
f C, 05% Dode-
cylphosphate 63 1083 3.4 0.045 55 1124 2.7 3.042 180 HV electrolyte 63 532 4.3 0.11 700 1114 4.4 0.041 1570 HV electrolyte
+ - $ 0.05 Dode-
cylphosphate 360 530 4.4 0.11 800 530 4.5 0.11 1150 360 528 0.11

In the following table 2 the test results are before and after the continuous voltage test (load on the electrolytic capacitors with nominal voltage at 85 ° C for 1000 hours) for high-voltage electrolytic capacitors reproduced.

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Table 2

electrolyte Nominal
span
tion Baseline C.
/ UF tg <f
% Z
. "at
1OkHz ¹ row
/ uA Values after permanent ver
search 3.4 Z
at
1OkHz
JTL ¹ row
/ UA V 1098 3.4 0.046 50 C.
/ UP 3.4 0.046 37 NY electrolyte 63 1083 3.4 0.044 55 1090 0.046 32 LV electrolyte
+ $ 0.05 Dode-
cylphosphate 63 1086

In the following Table 3 are the results of the flash test for High-voltage electrolytic capacitors for use in electronic flash units (360 V nominal voltage). Be in this test 5000 flashes with a sequence of 30 seconds and then one Carried out tension-free storage at room temperature for 4 weeks.

Table 3

electrolyte Nominal
span
tion C.
/ UP Baseline values Z
at
1OxHz
^ CL ¹ row
/ UA Values after 5000 flashes
and 4 weeks of voltage
loose storage
Clears enroeratur C.
/ UP tg / Z
at
1OkHz
-Q- ¹ row
/ UA V 534 tgcT
i> 0.08 600 521 4.7 0.10 800 HV electrolyte 360 533 4.2 0.08 700 525 4.6 0.11 550 HV electrolyte
+ $ 0.05 Dode-
cylphosphate 360 4.5

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Tables 1 to 3 clearly show the advantages of the operating electrolytes according to the invention. before All in all, the residual current increase is Ij, in the case of electrolytic capacitors with the operating electrolyte according to the invention after the endurance tests significantly lower than with electrolytic capacitors with conventional operating electrolytes.

2 claims
1 figure

TPA 9/140/2031 409819 / 04U

Claims (1)

Claims / 1. JBetriebselektrolyt for electrolytic capacitors as -d urch in that "known per se Hoehvolt-, low-voltage or low-temperature Betriebselektrol3 ^r th Oodecylphosphat in concentrate
tionen τοη 0.01 to 2 percent by weight based on the total amount of electrolyte is added. 2, operating electrolyte according to claim 1, characterized in that bodecyl phosphate in Form τοη mono- and didodecyl phosphate is contained in the operating electrolyte. A09819 / 0AU YPA 9 / HO / 2O31 Blank page