DE2258692A1 - PROCESS FOR THE MANUFACTURE OF CAPACITOR ELEMENTS WITH PARTICULARLY HIGH ENERGY CONTENT - Google Patents

Description

DfPL.-ING. A, GRÜNECKER - 8000 MDNCHEN 22

DRL-ING < H. Γ \ ιΐΝΓ \ ^ ι »ι ^ ι_ι * ■ * * v r— τι

DR.-fNG. W. STOCKMAtR, Ae. E. <caüf.inst.oftechn;) 2 2 5 B 6 9.2 Part ₁

Telegrams Monopoly Munich " Telex 05-28380

PATENT LAWYERS

P ₅₅₂₀

LICENCIA Talälfflänyokat Ertekesito V & llalat

Budapest V.,

Bajcsy Zsilinszky St. 16 Hungary

Process for the manufacture of capacitor elements particularly high energy content

A vast number of patents deal with the manufacture of electrolytic capacitors. These Capacitors are used where one is primarily large specific capacity is desired · that used Dielectric is a. Oxide of a metal like Al, Ta, Ti, etc # which have excellent insulating properties. The current electrolytic. Owe capacitors their high specific capacity makes these dielectrics. '

The experts see the further way of development in the fact that the surface of the positive electrode by various Procedure is enlarged (e.g. by using a sponge!

309823/0821

an aluminum foil). In their consensus the specific capacity depends geometrically only on the specific surface.

Apart from the specific surface, however, they do not draw any other geometrical factors are taken into account, although, as will be shown below, this is quite a play big balls.

The importance of the geometric factors and the advantages regular orientation have not yet been recognized.

As a special feature, the German patent Hr. 1 464, which does not have an electrolytic capacitor concerns, but here the regular orientation is already evident. Of course the description did of thin elementary threads, their orientation or their application in electrolytic capacitors no meaning yet

The regular geometric shape, in this case the Cylinders or their radius (r,.) Must be matched in a special way with the applied forming voltage (U) and the permitted dielectric strength (E_) of the dielectric be matched.

From the standpoint of specific capacity or specific energy content, the mutual position is the three factors are important, but not the specific surface.

As will be seen later from the mathematical proof and from the graphical representation, the magnification increases the specific surface area over a certain amount

309823/0821

Beyond the limit, the specific capacity is no longer, but rather lowers it quickly.

By taking these factors into account, the invention provides a thread-like electrolytic capacitor in which the factors together ensure that the specific energy content is a multiple of the current value.

The invention relates to a method for producing Capacitor elements with a high specific energy content for electrolytic capacitors, in which using a forming voltage U on the surface of the metal thread an oxide layer with a dielectric strength E is formed which is characterized in that the metal thread used for oxidation has an unetched circular profile with a radius between 0.5 U / E and 60 U / E.

m * -

The radius of the metal threads used is preferably 2 "U / E _m ·

The method according to the invention is described in more detail below will be explained with reference to the accompanying drawings. Show it:

3 0 9823/0821

1 shows an illustration to explain the relationships of a cylinder capacitor,

Fig. 2 shows an exemplary embodiment of an according to of the invention designed capacitor schematically in cross section,

Fig. 3 is a graph showing the specific Energy content is plotted as a function of the inner radius r ,, and

FIG. 4 shows a longitudinal section through the capacitor shown in FIG. 2.

The capacity of the coaxial cylinders is determined by the formula:

c _f .

Calculated where

^r 1

r, -, = radius of the outer cylinder Ty. = Radius of the inner cylinder £ = the length of the cylinder £ = the relative dielectric constant C = the dielectric constant of the vacuum

means (Fig. 1).

The specific capacity is determined by

C.
Q = - ^ j- given where

'f

V = T ₀ It t is the volume of the cylinder.

309823/0821

In — Ä τ » ^e 7 / V 1η ~ - £ · ρ J-

^xu ν _Λ ^τ Ζ H £ ^ ν _Λ -2

The field strength in the case of coaxial cylinders is

T ₁

it follows from this

r ₂ U

^r 1

Q ^

It can be taken as a constant

wodureli si hurry

^f υ a

This equation may depend on the value of the ¥ @ F & age r ^ g. According to this, the extreme value of the! "Unction, xmä his!" Age is determined »■

Γ /

C m k -

T ₂

1 ^E m

Thus becomes

0 _Λ . k

2 U. -2

e 2 U.

The first derivative of the function - ^ - iot - '-Iy ι? U 2

2 U

• ¹ ^

_2_ ^Γ 1 ^Ε ι>

2U

In the case of the extreme value of the puncture, CL. ¹ * 0; if k / 0, which is only possible if

309323/0821

2 π

C? ^ΓιΕ

" O. This leads to:

2 π ι

2 -U ^ _n 2 U

2 U

from this follows:

This means that the specific capacity reaches its maximum value at this value of r i. achieved.

The method according to the invention is carried out in - the following: '

The dielectric 002, which. consists of the oxide of the base metal. The individual capacitor elements connected in parallel are located in the capacitor 003 surrounded by the electrolyte.

The constructive training is based on Figures 2 and made clear.

3Q982 3/082

Example 1:

If desired, the voltage of the capacitor is specified, whose value for electrolytic aluminum capacitors is 450 V.

At present the forming voltage is U «36O V.

The permissible breakdown voltage of the dielectric becomes with

. E _m - 10,000 kV / cm
accepted.

This value depends on the purity and the technology used to manufacture the raw material.

- 10

Due to the above, the optimal dimensions of the electrolytic filament capacitor, as well as the value of the highest achievable specific capacity can be determined.

2 U 2.0.36

07210 "^ cm

10,000

The smallest thickness of the on the radius (r ,,) of the inner The insulating layer that forms cylinder must theoretically

be so

309823/0821

0.36

0.72.KfIlO ⁴ T ₂ = 0.72, io " ⁴ .l, 66» l, 195ao " ⁴ The specific energy content" is

c _f «-: & 5l ♦ ^r i. ₌ ^a * ^c

^Γ 2

36 ² 2.5.1O- ⁴ _. 16.2 Wsec / cm ⁵

From this 20 % are deducted as unproductive volume, which is filled by the electrolyte surrounding the thread.

16.2

- 5.24 ■
12.96.

The actual specific energy content is therefore * - '13 ¥ sec / cm · ^.

With other r ^ values the function always results in smaller ones Energy ^ or capacity values (Fig. 3, curve 2).

The current highest specific energy content the curve (5) indicates, the function in FIG. 3 is achieved at

40 U

309823/082 1

Example 2:

The quality of the dielectric is unchanged (FIG. 3, curve 1).

So E _m * 10,000 kV / cm
6 _r = -10

The forming voltage of the capacitor should be reduced to U = 100 V.

In this case too, the value of the highest specific capacity can be determined in the same way which increases, but the specific energy content remains unchanged. It can also be observed that the reduction in tension makes the curve sharp, whereby the curve changes steeply. When the radius is reduced below the value r ,. «2U / E will, though then the specific surface increases, the specific capacity or the energy content decreases steeply. Due to the inhomogeneity of the field, the best current increases above a certain limit, and full breakdown can occur take place.

example 3 '

The dielectric strength has been increased

E _m m 12 500 kV / cm

U = 360 V

30982 3/0821

The change takes place according to Fig. 3 »curve (4).

Example 4:

E _m »12,500 kV / cm

U = 100 V

The lower voltage gives a steep curve, Fig. 3 (Curve 3).

The examples listed prove that the. Size of specific surface area is not a determining factor.

E.g. a capacitor with U = 100 Y voltage reaches at r ,, = 5 / im not even the maximum of the current one Energy value (approximately 1.5 Wsec / em) while using the same Isolation material constants, a 3 to 5-fold energy content can be achieved with the same dimensions., For this -Just increase the tension. ;

The procedure is for the storage of large amounts of energy " in a small space, or is suitable for the production of apparatus of this type. With dielectrics, which have a higher dielectric constant, the level of the specific energy content of the lead-acid batteries can also be achieved.

0J9 8 2.3 / 08 2.1

Claims (2)

Claims 1.] Process for the production of capacitor elements high specific energy content for electrolytic capacitors, in which using a forming voltage U an oxide layer with a dielectric strength E is formed on the surface of metal threads, characterized in that the for Oxidation metal threads used an unetched circular profile with a radius between 0.5 U / E and 60 U / E exhibit. 2. The method according to claim 1, characterized in that the radius of the metal threads used is 2 U / E _m . 309823/0821 Blank page