DE1596091B2 - GALVANIC PRIMARY ELEMENT WITH A POROUS NEGATIVE ELECTRODE AND A DEPOLARIZER SEPARATED BY A DIAPHRAGMA AND METHOD FOR MANUFACTURING THE DEPOLARIZER AND THE DIAPHRAGM - Google Patents

Description

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Platelet shape emerged, with the grain size in the small pore size having a peculiar effect. Contains usually exceeded 0.05 mm. It was also known, namely the primary element mercury, be it that Silver oxide precipitated from a solution of the depolarization - this is a component of the depolarizer or as mix in torsubstanz and later in the finished means to enlarge the hydrogen overspan depolarizer electrode is added electrochemically to silver to 5 voltage of the negative electrode, this occurs reduce, whereby very fine silver particles with mercury in spite of its large surface tension result in a grain size below 0.01 mm. It is through the pores of the diaphragm and caused with also became known, from Depolarization the time during the discharge of the element torsubstanz existing grains each with a thin metallic short circuit between the electrodes. To provide silver coating and this afterwards by io When reducing the thickness of the diaphragm Blow up deformation of the grains. In a body element coated with a silver layer for the purpose of increasing the power density of the primary, the described appearance takes place naturally A depolarizer formed is, however, even faster. To remedy this disadvantage, nismäßig large amount of silver is required, which expediently resorted to substances which have pores of molekula-25 Should be percent by weight and more. 15 ren dimensions, if at all

The object of the invention is to provide a galvanic principle that can still be referred to as pores. It is this märelement of the type mentioned with increased mainly organic film-forming substances, To create power density in which primarily it contains the hydrophilic, mostly hydroxyl groups. Volume of the depolarizer by reducing the B. regenerated cellulose, amount of cellulose the mixed ether, hardened gelatine or similar natural law used to impart electrical conductivity Silver powder is reduced without there being any additional products, and is also partially insoluble in water the internal resistance of the element increases polymers of polyethylene derivatives, such as. B. becomes part, wise esterified, etherified or acetalized poly-

According to the invention, this object is achieved by vinyl alcohol. All of these products have in common

that the grain size of the silver powder is between 0.01 and 25 that they swell in water or aqueous solutions

and 0.04 mm and that the depolarizer is approximated and thus suffered considerable loss of strength. It

shirt contains 5 weight percent silver powder. it is therefore not possible to obtain sufficient

It was found that with silver powder the appropriately firm and non-tearing diaphragms are lower

given grain size to produce optimal values in terms of thickness.

Required amount of the silver powder and the amount obtained. The invention therefore provides a further embodiment

Specific electrical resistance of the Depolari- also a process for the production of the diaphragm

sators can be achieved. In the case of a primary element for the galvanic primary cell, namely a

drive with a negative zinc electrode and a positive one, which prevents the formation of an un-

Depolarizer electrode made of mercury oxide and permeable, extremely thin and yet tear-resistant

a silver powder content of about 5 weight per 35 diaphragm, so that the power density of the

cent, whereby the grain size of the silver powder between galvanic primary elements can be increased further

0.01 and 0.04 mm, the result is a specific can. This method exists according to the invention

Resistance of only 0.2 ohm cm, which is exceptional in that as the starting material for the diaphragm

can be called homely low. Become a solution of a saponifiable cellulose compound

specified limits of grain size down or 40 used and this solution in one layer over a

exceeded above, with the same silver powder used as reinforcement insert made of fabric or felt

mix the resistivity of the Depolarisa- is poured and dried so that a film is

tors considerably larger. Not even by a bigger one, and that afterwards the foil by chemical ones

ßere amount of the added silver powder can implementation an ionic conductivity is given,

then the specific resistance in each case to 45. In this way, perfect diaphragm

keep the same low value. Manufacture men only 0.2 mm thick. It can do it

The inventive method for production according to a further embodiment of the method has advantages Depolarizer be liable for the above, the starting material for the diaphragm The primary element consists in adding a plasticizer from an aqueous solution, which is the case with the chemi-silver nitrate solution by adding. Sodium hydroxide solution see conversion into water-soluble cleavage products silver oxide is precipitated with constant stirring, then falls, which is separated from the diaphragm by soaking Solution of formaldehyde as a reducing agent.

added in portions and the resulting silver The invention is washed, dried and the depolarization purely for example explained in more detail below using the drawing powder,
cup mass is added. 55 Fig. 1 shows a test arrangement constructed

This method allows without difficulty, the tes galvanic primary element according to the invention

desired grain size of the silver powder between in cross section;

0.01 and 0.04mm to get, while known at- Fig.2 represents the discharge curves of different

their method to either larger or smaller known and a primary according to the invention

Particle sizes lead that do not produce such good results.

remote, as set out above. The in F i g. 1 illustrated experimental arrangement

It stands to reason that the power density of the galvanic takes no account of a low housing volume.

Primary element by reducing the thickness of the men and only served to investigate how far the

Diaphragm between the negative electrode and capacitance for a given effective usable volume

the positive depolarizer electrode can be further increased.

hen. Up to now, however, there have been difficulties. A lower housing part 1 made of brass

of various types. If a micropo- 0.11 mm thick silver-plated diaphragm is used and has a clear interior

If the material used is pink, it shows itself to be extremely wide with a diameter of 18 mm. In the lower part 1

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there is an insulating ring2, e.g. made of polystyrene or percent formaldehyde, which contains 1% hydrochloric acid, an ethoxylin resin. Hardened within the ring 2. After soaking, the foil is found again the positive or depolarisa- dries up.

gate electrode 3, their design and manufacture. A diaphragm made in this way of only

is explained below. On the one drop 5 0.2 mm thick and 1 cm ² area points opposite to a

Electrolyte, e.g. a 40 weight percent potassium hy normal potassium chloride solution has a resistance of

Aqueous solution containing hydroxide, wetted de- less than 2 ohms. This value is in general

polarizer electrode 3 is a separator serving less than 10% of the total internal resistance

Diaphragm 4 placed, which has a thickness of 0.2 mm and the cell.

the insulating ring 2 overlaps. Training and manufacture io The training of the depolarizer electrode 3 is development of the diaphragm are described below. using the example of mercury oxide as a Depolarisa-Auf the diaphragm 4, a second insulating ring 5 is explained as entorsubstanz. It has been found that to respond placed on the insulating ring 2. One to one with sharing the necessary electrical conductivity Drops of electrolyte moistened diaphragm 4 set of only 5 percent by weight of silver powder for is a porous, electrolyte-soaked, amalga- 15 mercury oxide is sufficient, provided the silver powder laid zinc electrode 6, which has a negative grain size of 0.01 to 0.04 mm. The so The electrode is formed and the depolarizer electrode formed within the insulating ring 5 has a spebefindet. The total pore volume of the electrode 6 specific electrical resistance, which is less than is expediently 55 to 60%. In an annular groove 10 is 0.2 ohm cm.

of the lower part 1 is a rubber seal 11 is 20 The production of a silver powder, which a

lays on which the edge of a lid 12 rests. Has a grain size between 0.01 and 0.04 mm,

Like the lower part 1, the cover 12 consists of, for example, done as follows: In a suitable

bertem brass. A glass vessel made of insulating material and equipped with a stirrer weighs 120 g

Clamping ring 13 is with the help of screws 14 with the crystallized silver nitrate with distilled water

Lower part 1 connected and presses the lid 12 to 25 brought to a volume of 250 ml. Under steady

the sealing ring 11 and the negative electrode 6. intense stirring, 250 ml of an aqueous

The cover 12 is with the porous zinc electrode 6 solution, which contains 50 g of sodium hydroxide solution, during a

electrically connected and forms the negative minute slowly added. To the precipitated SiI

PoI of the cell, during which with the depolarization superoxide, always with stirring, without the overlapping

gate electrode 3 connected lower part 1 to remove the 30 h liquid, 60 ml of formaldehyde,

represents positive pole. 30 percent by volume, as a reducing agent in small amounts

So that the thin diaphragm portions serving as a separator are added, i. H. it is always before the

ma 4 has sufficient strength, it is waited with further additions until the strong

reinforced with a fiber material. The production of the incipient development of carbon oxide calms down

Diaphragm takes place z. B. by the following procedure: 35 has. After adding the required amount

A thin tissue with about 1000 to 2000 Ma formaldehyde is waited 10 minutes, sucked off,

see per square centimeter or a corresponding electrolyte-free washed and with a little pure ether

Fleece, consisting e.g. of cellulose, organic nol rinsed and then rinsed for 12 hours

Synthetic fiber, fiberglass or other fiber material, dried at 70 ° C. The dry silver is before the

is stretched on a ring in order to expediently pass through a fine sieve, e.g.

plan to be fixed in position. Then the nylon fabric (bag gauze) is passed through.

on a polished, precisely leveled plate, e.g. B. from The manufacture of the depolarizer electrode 3 can Glass, placed. A solution of 10% Aze- z is then added. B. be carried out as follows: In a porcelantyl cellulose In a solvent mixture from shell, 0.82 g of polystyrene in 5 ml are twice de-90 Percent by volume of methylene chloride (CH., C1.,) And distilled benzene dissolved. With gentle rubbing 10 percent by volume of ethanol poured on, the "amount of which is 5 g of the silver powder described above corresponds to the desired layer thickness. After setting and drying homogeneously with the polystyrene solution the solution creates a film that mixes. Then about a quarter of the necessary Thickness should not exceed 0.2 mm. So that the amount of 94.2 g of red mercury oxide was added dry film when detached from the carrier plate 50 and rubbed intensively until a dark brown one does not tear, the solution becomes a saponifiable soft mixture. With the addition of other Pormacher, z. B. dimethyl phthalate added. The dry mercury oxide is treated in the same way The foil is still torn up on the ring until the whole amount has been added. During this tense, for about 50 hours at 90 ° in a 30% operation, which is to be carried out in the fume cupboard Saponified caustic soda. This chemical reaction means that the mass will always be covered by benzene. Then it will be The foil is given ion conductivity. The benzene with constant stirring on the Plasticizer disintegrates in this chemical conversion water bath, so that the mass into water-soluble cleavage products. After thorough- not stuck together. The hot mortar is in After washing the foil, it is placed in a vacuum desiccator at room temperature and the depolarization is dried. Because the fabric or fleece is completely under water jet vacuum during the 60 gate mixing The entire treatment is freed from benzene stretched on the ring.

remains, the film falls into folds after drying. follows under a pressure of 6 to 81 per cm ² . thanks to

According to a variant of the method, this high compression is obtained in the ring with moldings

held fiber material with a solution of 10% 65 favorable mechanical properties.

Polyvinyl alcohol in distilled water to the same The practical suitability of the described, invented

Way doused. After drying and detachment, measures according to the invention were carried out on the in FIG. 1

The foil is examined for 3 hours in 10 volume shown primary elements. That used

Diaphragm 4 was reinforced with a cotton fabric and made from regenerated cellulose. as Depolarizer substance was used mercury oxide as described above.

The primary element thus formed was discharged with a constant current of 1 milliamperes. Under the same conditions, a commercially available special zinc-manganese dioxide element with a high power density and a likewise commercially available zinc-mercury oxide primary element with the hitherto highest known power density were discharged. The effective useful volume, ie the space occupied by the negative electrode 6, the diaphragm 4 and the depolarizer electrode 3 of the three primary elements compared with one another was identical. To determine the achievable number of ampere-hours, a voltage of 1.1VoIt was discharged. The relatively high internal resistance of the zinc-manganese dioxide element

In order to obtain comparable values, mentes only allowed a discharge current of 0.01 amperes.

Fig. 2 shows the determined discharge curves. The curve 21 associated with the zinc-manganese dioxide element shows the strong voltage drop during the discharge, which is characteristic of these elements but is undesirable for many purposes. The power density of the element is only 143 m Ah / cm ³ . The curves 22 α and 22 b are the discharge curves of the im

ίο Commercially available zinc-mercury oxide elements. The performance obtained from these elements is consistent with the information provided by the manufacturer. The power density is 190 m Ah / cm ³ . The curves 23 α and 23 b were with test elements of the with reference to Fi g. 1 received training described and clearly show what significant progress the measures according to the invention brought. The power density has increased to 500 m Ah / cm ³ , which has never been achieved before.

1 sheet of drawings

209541/374

Claims (4)

1 2 most current-supplying elements hardly any change Patent claims: experienced. In the general form, an electron-donating substance (negative electrode) is associated with a 1. Galvanic primary element with a high level of electrons (positive electrode) power density with a porous negative electrode 5 brought to reaction in such a way that the at the Umsettrode and an amount of enthalpy released by it through a diaphragm practically loss-separated Depolarizer, from which electrical energy can be withdrawn in the form of electri- cal energy tric conductivity is added to silver powder. It is used for the transport of charges characterized in that the ions inside the element between the two grain sizes of the silver powder between 0.01 and 10 different electrodes uses an electrolyte, 0.04 mm and that the depolarizer also has the task of transporting substances shirt contains 5 weight percent silver powder. has to take over. The conditions are then 2. Process for the production of the Depolarisa- special favorable when the electrolyte at the Umsettors for the primary element according to claim 1, that only participates as an intermediate, d. H. if he is neither in characterized in that from an aqueous SiI- 15 its composition is still in its concentrate nitrate solution by adding caustic soda tion suffers a change. That means that the silver oxide is precipitated with constant stirring, then arises during operation of the galvanic element a solution of formaldehyde as a reducing reaction products are insoluble in the electrolyte tion agent added in portions and the un- and deposit on the negative electrode, the standing silver powder is washed, dried and consequently experiences an increase in volume. To do it the depolarizer is added. an increase in the external dimensions of the negative 3. To avoid the process of making the diaphragm of the electrode as much as possible, this is done in designed porous for the primary element according to one of the known manners, the claim 1 or 2, characterized in that the total volume of the pores should make up 55 to 60%. The starting material for the diaphragm is a solution. 25 The pores replace a separate dilatation solution a saponifiable cellulose compound is lost within the galvanic element and is used and this solution in one layer over nen at the same time for receiving and storing the a reinforcement made of fabric electrolytes. Since in this case an additional elec- or felt is poured and dried so that trolyte space between the electrodes is unnecessary, a film is produced, and a diaphragm (also called a separator) is then placed between the film 30 chemical conversion an ion conductive see the electrodes provided to a direct Bekeit is granted. to prevent the electrodes from touching, but without the 4. The method according to claim 3, thereby preventing the passage of ions. indicates that the starting material for the on of the positive electrode is produced by chemical A plasticizer is added to the diaphragm, the polarization sees a hydrogen separation, in the chemical conversion into water-soluble which the effectiveness and the shelf life of the Fission products disintegrates, which is affected by soaking from the element, if this polarization removed from the diaphragm. is not suppressed by a depolarizer that an oxygen supplying chemical substance, such as 40 e.g. contains mercury oxide. Since the Depolarisa- substances in general in their use temperature show neither ionic nor electronic conductivity, the depolarizer can function Only comply with the addition of an electrically conductive substance. It is known to use the depolarizer substance to The invention relates to a galvanic primary division of electrical conductivity graphite or silver element high power density with a porous ne-powder and partly also iron or nickel wool negative electrode and one of it with a slide. phragma separate depolarizer, which is used to issue graphite powder, although it has the advantage of being more electrically conductive Conductivity silver powder is added. 5 ° nism moderately low cost price, is however for Furthermore, the invention relates to a method for cooking the present purpose having the disadvantage position of the depolarizer and a method for that it the hydrogen overvoltage on metals Manufacture of the diaphragm for the primary element. greatly reduces and thereby the galvanic element The transistor has deteriorated the miniaturization electronically and that graphite because of its relative shear circuit arrangements promoted in such a way that 55 low electrical conductivity in considerable z. B. has become possible to watch wristwatches with a quantity, e.g. B. up to 30 percent by weight, the depolar electric To provide drive. Since such a sator must be added, what the aspiration of a Circuit arrangements that use as an energy source Increase in power density by wasting volume galvanic primary elements run counter to a substantial reduction in the galvanic element, 60 In the case of silver powder, smaller amounts of addressed, understandably striving to keep the 10 weight percent or more as sufficient Power density, d. H. the energy storage capacity found. With less than 10 weight percent silver pro Unit of volume of such primary elements, possibly powder in the depolarizer, has become the inner repugnant to enlarge. In some cases the galvanic element was found to be undesirable the volume of the energy source has proven to be high above the practical 65. This can be used as a conductivity additive of a certain device at all. dete silver powder has hitherto generally been carried out by The principle of galvanic or electrochemical grinding is produced and crushed, with powder particles See power generation since the discovery of the er of inconsistent size and essentially with