DE1421582A1 - Primary cell - Google Patents

Description

O 4 Ψ O O

DIPL.-INQ. H. SCHIFFER

Patent attorney
Karlsruhe / Baden 1421582

Patent application (7647)

Mallory Batteries Limited, G-atwick Road " Crawley, Sussex / England

Primary cell

The invention relates to an alkaline primary cell, in particular one containing a polarizing oxide varwendet, which is mixed with carbon or graphite and in contact with the steel container serving as the cathode is.

In many applications it is very important to get an initial discharge current that is a maximum. This requirement is particularly important for flash lamps, because the lamp does not ignite when the current is on is insufficient. to ensure this high discharge current, it is necessary to reduce the contact resistance between the cathode depolarizer and the cathode container as possible to keep it small. An additional problem results in "

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see from this that the current, even if the cell supplies a sufficient initial current, later after one certain accumulation falls below an acceptable level ". This phenomenon is primarily due to one Reduction of the density of the De pola, ri sat or-G-emi s ehe s, which as a result, the electrolyte penetrates the mixture. This increases the voltage drop or

the contact resistance between the depolarizer and the cathode container made of steel or nickel-plated steel, the ignition current being reduced. aside from that In MnOp cells, the contact resistance between the

and the Ni deposition due to oxidation. That is . also the pail if silver plating is used.

Some embodiments of synthetic MhOp yield a Contact potential between the sulfide * and the silver sulfides. Here, the contact resistance is increased for a period of time.

It is unlikely that in the known per se Zinc-silver oxide cells the depolarizing oxides, e.g. UnOp, are reduced to a metal. The cells response results in Mr ^ O. *, which still has a higher potential drop on

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Cathode container results in MnO ₂ · During operation of the cell, the potential drop will normally increase, with the ignition current decreasing.

The present invention aims, inter alia, with a high ignition current and a low contact resistance between the Depolarizer and the steel container forming the cathode can be achieved.

According to the invention, the primary cell has a metal cathode with a gold plating, a cathode depolarizer, which is in contact with the gold plating, an anode and an electrolyte.

An expedient embodiment of the invention consists in a primary alkaline cell with a zinc-amalgam anode, a cathode depolarizer consists of a mixture of 91 i> MnO ^ and 9 i "graphite dust in macrostructure and a container made of steel or nickel plated steel. A spacer is mounted between the anode and the cathode depolarizer and is intended to prevent contact between the anode and the cathode depolarizer and to absorb and retain certain amounts of the electrolyte. Dor electrolyte is a solution of KOH in zinc potfcasehe-

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Water (potassium zincated water). There is a low resistance thin gold plating provided, which is in contact with the cathode depolarizer.

The cathode-Depolarisatof forming, from 91 ^ synthetic MnO ₂ existing with 9 ί> graphite dust in microstructure mixture is pressed into the form of cylindrical tablets ihrersei-ts are pressed into the steel Eathodenbehälter which on its inner surface a gold plating owns.

The spacer is expediently made of spirally wound Cellulose formed with an outer cover of parchment paper. This spacer is radially inside of the cylindrical depolarizer tablets provided. Cylindrical anode tablets aue zinc amalgam with 13 56 mercury are in the axial opening of the Spacer stored. These tablets rest on one Neoprene block or a compression abutment, which makes the contact with the bottom of the cathode container prevented.

The electrolyte is injected into a central opening of the anode tablets and enters the spacer, which absorbs it. This swells

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the spacer and falls the space between the anode and the cathode, with good electrolytic contact between these two elements. comes up.

The inner and the outer cover are provided with an insulating ring, the outer cover in the inlet can be pressed into it. This closes the cell, while the anode tablets against the compressible Neoprene block is pressed, making good contact with the lids.

In the accompanying drawings, in which the same reference * symbols denote similar parts, shows:

Pig. 1 is an elevation, partly in section the cell according to the invention and

Fig. 2 is a table showing the ignition currents of cells

compares a period of 6 months with each other, / in which the inner surface of the B. container on the one hand has a gold and on the other hand a silver plating.

The cell 1 consists of an outer vessel 2, a cathode container 3, a cathode depolarizer in the form of a cylindrical

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shear tablets 4 and one of cylindrical zinc ' Amalgam composed of existing! Doublets 6 formed anode. A spacer 5 is located between the anode and cathode, and an absorbent sleeve 7 is between the outer vessel 2 and the cathode container 3 stored. A hanging 8 made of plastic prevents contact between the vessel 2 and the container 3 on the one hand and the inner cover 9 and the outer cover 10 on the other hand. Double lids are provided to prevent leaks Avoid allowing the electrolyte to creep to the outside of the cell.

Below the zinc tablets 6 a press block 12 is mounted, which prevents the tablets with "the "Container 10 come into contact, and which also, due to its elasticity, the tablets 6 against the inner Cover 9 presses. This results in an extremely good contact between the anode and the connections used Lids achieved. The outer Deokel 10 forms the anode contact 11, which helps ensure that a good outer Contact is made.

The gold plating 13 is deposited on the container 3 by means of electroplating or galvanic contact plating, so that a good contact between cathodes ^ ütfal * -rCS4, ioy ¥

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and the container 3 is achieved. This reduces the contact resistance and increases the ignition current by around 25 % .

Tigur 2 records the results of ignition current tests in which cells of the type shown in FIG. 1 were used, which contained a _{depolarizer consisting mainly of MnO 2} , a zinc amalgam anode and an alkaline zinc electrolyte.

The cells were identical with one exception. The exception consisted in the depolarizer container made of steel in one case were silver-plated and in the other Sail were gold-plated. 100 cells of each variety were charged and measured at room temperature. The mean values were determined from the readings in each group and shown graphically in FIG.

The present invention provides generally similar results. Results when cells are used whose depolarizer consists mainly of HgO.

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Claims (1)

£ atenta_nspruehe 1 "Priaärselle, characterized in that the Si · a · Metallkethode with gold plating" inen cathode depolarizer ά · τ ait of the gold plating is in contact, has a Ancda and an electrolyte. 2. Cell aa «h claim I ₉ characterized in that the Xstheden depolarizer consists of langandioxyd eAer Queek silver oxide with a small admixture of fine oil dust. 3. Cell according to claim 1 or Z _9, characterized in that the electrolyte consists of an aqueous solution of caustic potash containing 2ink. 4 · Cell according to claims 1, 2 or 5, characterized by a spacer that absorbs the electrolyte, which is stored as the anode and the cathode depolarizer. 5. Cell according to claim 1, 2 or 3, characterized in that the cathode has the pona of a «yliadrisehen , gold-plated steel housing which accommodates the cathode depolarizer and the anode, both of which have the pora 809806/06 13 (7 * 47) syliaAviseh «n I» bl «tt« n fc * l »« A »« «loh · dureh« inta «Yli * dri» eli * n, d «n electrolytes abi» rbi # r «nd« n At-8tandeli »lt« r too ftinaad ^ r getrtnat »ind. 6. Sell "according to Anepruoh 5" because it identifies that The anode is made of 2ink-Aaalgaa b «ht. 809806/0613