DE2027721A1 - - Google Patents

Description

Dip !. Ing.R. Merteos

Patent attorney
jB Frankfurt / Main 1, Ammelburgstr. 34-

WA *. Frankfurt am Main,

June 4th 1.9? O

H 51 P 206 ^

HONEYWELL INC. ■
2701 Pourth Avenue South. Minneapolis, Minn. / USJL

"Electrochemical power source ¹¹

The invention relates to electrochemical power sources with an anode »a cathode and a water-soluble electrolyte, which when the power source is activated in the form of an aqueous solution in chemical contact with the anode and the Cathode is. The invention is equally applicable to immediately active and also to subsequently activated current sources. In the case of the instantly active power sources, the anode, the cathode and the electrolyte are used immediately during manufacture brought into active contact with each other, while with subsequently activated power sources one or more of these components, usually the electrolyte or an electrolyte solvent, initially kept away and only at the time the desired activation is added. In the case of such, retrospectively Activatable cells, the electrolyte is often stored in a container within the power source and to activate the container destroyed, so that its contents in the space containing the actual cells of the power source can occur. The power source can contain one or more electrochemical cells which together form a battery.

The use of an aqueous electrolyte solution in one

to the
Electrochemical cell is associated with / disadvantage that the water evaporates from the electrolyte solution over time as a function of the ambient pressure and temperature of the cell, whereby the total operating time of the cell is shortened. The invention is primarily concerned with elimination

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or at least reduce this disadvantageous phenomenon * and has the task of improving the structure and efficiency of electrochemical cells of the type mentioned above.

To solve this problem, the invention provides that the

a
Contains power source / hygroscopic substance, which absorbs at least part of the water required as a solvent for the electrolyte and, if necessary, stores it «

The hygroscopic substance can enter the Cell can be introduced. In the case of immediately active power sources, it can, for example, in the aqueous solution of the electrolyte be dissolved and introduced into the cell together with this or it is in a dry state with the The basic material of the electrolyte is mixed and introduced into the cell, so that it sucks water into the cell and humidifies the base material of the electrolyte, which causes the cell to activated after a short delay time. With retrospectively activated batteries, the hygroscopic substance is either mixed with the aqueous electrolyte solution or in the dry State mixed with the base material of the electrolyte in a hermetically sealed container within the power source stored, for example, in a plastic bag, which is used for Purposes of activation is destructible.

The hygroscopic substance preferably simultaneously at least partially forms the water-soluble base material of the electrolyte and thus serves either alone or in conjunction with another water-soluble electrolyte base material as a source for the ions in the aqueous solution as soon as the cell is activated. In a preferred embodiment of a power source of the last-mentioned type, the hygroscopic substance, mi.% _{? a} i mixed with the cathode material. It can either be dissolved in and then mixed with the cathode material. to make a paste or a pulp or it will in dry

η fi Q π ζ "? / 1 ζ%%

State mixed with the cathode material and pulls due to Its hygroscopic properties allow water into the cell to form the required aqueous electrolyte solution. in the In the latter case, the water content of the electrolyte solution moves practically completely from the activated power source Effect of the hygroscopic substance. In this embodiment, there is no need at all for the electrolyte solvent Introduce into the cell, but this activates itself when the hygroscopic substance is exposed to the atmosphere will. It is then used to replace the water that evaporates or leaks during operation, by sucking up this water vapor or this water or additional water vapor from the atmosphere. This replacement of the escaping The hygroscopic substance also serves water when it is already dissolved in water to form the aqueous electrolyte solution.

As a hygroscopic substance is suitable for the purposes of the invention especially lithium chloride, zinc chloride, magnesium hydroxide and magnesium chloride. Zinc is preferably used as the anode material, although other electropositive metals are also used are practically stable in an aqueous electrolyte solution, can be used.

The invention can be used to produce one with an anode, " a cathode and an aqueous electrolyte solution To protect the electrochemical cell against decomposition by introducing a hygroscopic substance into the cell, which is any Water losses of the electrolyte fluid are compensated and thereby extends the life of the cell.

The following are some preferred embodiments more electrochemical Power sources according to the invention described. In Examples 1 to 10, the cell each has a zinc anode,

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which by means of a porous, non-woven, fibrous separator is separated from the cathode and has an effective surface area of about 6.5 cm. In the active state, the cathode is paste-like or pulpy and contains a hygroscopic in a mixture Substance that is also a water-soluble basic substance of an electrolyte. A carbon film cathode terminal is pressed onto the cathode material and forms the positive connection terminal of the cell. In all examples the cell showed a remarkable ability to retain vapor in the electrolyte.

fc example 1

The cathode consists of manganese dioxide and carbon powder mixed together with an aqueous electrolyte solution which is in water contains dissolved zinc chloride. The zinc chloride forms both the hygroscopic substance and the basic substance of the electrolyte.

When tested, the cell generated an open circuit voltage of 1.67 V and a short circuit current of 1.5 A. When loaded the cell resulted in the following values:

Tension load

Volts ohms

1.62 100

1.59 50

1.55 30

1.50 20

1.40 10

1.26 5

Example 2

The cell has a cathode composition as in Example 1 with the exception that instead of zinc chloride in the aqueous one Electrolytic solution lithium chloride is used. During the exam

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this cell produced an open circuit voltage of 1.85 V and a short-circuit current of 1.8 A. With different loads the following tensions resulted:

tension Example 3 load volt ohm 1.78 100 1.74 50 1.70 30th 1.63 20th 1.51 10 1.34 5

Here, with otherwise the same cathode composition, magnesium chloride was used instead of zinc chloride in the aqueous solution Electrolyte solution used. The cell gave an open circuit voltage of 1.71 V and a short circuit current of 1.5 A. At the following tensions arose under various loads:

tension example load 4th volt Ohm 1.62 100 1.60 50 1.56 30th 1.51 20th 1.40 10 1.21 5

A cathode composition was used as in Example 1, with the exception that the manganese dioxide was hygroscopic and instead of zinc chloride, magnesium dioxide was used in the electrolyte solution. The cell delivered an open circuit voltage

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of 1.5V and a short-circuit current of 50 mA.

Example 5

The cell had a cathode composition as in Example 2, and the electrolyte consisted of a solution of one part of lithium chloride in two parts by weight of water, with ammonium chloride being added at 10 g per 100 ml of aqueous electrolyte solution. During the test, the cell generated an open-circuit voltage of 1.88 V and a short-circuit current of 1.6 A. The voltage measurement under load gave the following values:

tension Example 6 load volt ohm 1.78 100 1.74 50 1.70 30th 1.64 20th 1.50 10 1.32 5

The cathode contains mercury oxide and carbon powder in one Volume ratio of 1: 2 mixed with an electrolyte solution of one part of lithium chloride in two parts by weight Water. In this example, the lithium chloride formed both the base of the electrolyte and the hygroscopic one Material. At room temperature, the cell generated an open circuit voltage of 1.06 V and a short-circuit current of 0.8 A. The Measurements of the cell under load gave the following values:

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tension Example 7 load volt ohm 0.98 100 0.95 50 0.91 30th 0.88 20th 0.80 · 10 0.69 5

The cell has a cathode composition as in Example 6, with the exception that instead of mercury oxide, citric acid iron oxide is used as the cathode material. The cell produced an open circuit voltage of 1, ¹ I ¹ IV and a short circuit current of 1.0 A. Under load, the cell voltages were the following:

tension example load 8th volt Ohm 1.40 100 1.37 50 1.33 30th 1.28 20th 1.16 10 0.97 5

The cell has a cathode composition as in Example 6, except that instead of mercury oxide, sulfur is used as the cathode material used. The cell generates an open circuit voltage of 1.48 V and a short circuit current of 0.4 A.

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Example 9

The cathode composition is the same as in Example 6 ,,. except for using metadinitrobenzene instead of Mercury oxide. The cell generated an open circuit voltage of 1.53 V and a short-circuit current of 0.5 A.

Example 10

The cathode material is vanadium pentoxide instead of mercury oxide (VJ3_) used. This cell generates an open circuit voltage of 1.63 V and a short-circuit current of 1.8 A. When the cell was loaded, the following values were obtained:

tension load volt ohm 1.50 100 1.42 50 1.38 30th 1.33 , 20 1.27 10 1.16 5

The above examples illustrate the use of hygroscopic Substances in electrolyte solutions of electrochemical power sources in the activated state. As mentioned earlier, can the hygroscopic substance in the power source also used to soak up water from the atmosphere for the purpose of initial activation of the cell. For these purposes the hygroscopic material was used in the following example.

Example 11

The cell has an effective surface area of 12.9 cm and uses a zinc anode, which by means of a porous, non-woven, fibrous separator from a cathode containing manganese dioxide

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is separated. Lithium chloride was mixed with the cathode material in a dry state and the cell was stored without adding water. During the test, such a cell initially generated an initial voltage of O ₃ IV and no measurable current. After a storage time of 6 hours, it generated an open-circuit voltage of 1.5 * 1 V and a short-circuit current of 0.111 A.

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Claims (9)

Claims Electrochemical power source with an anode, a cathode and a water-soluble electrolyte, which when activated Current source in the form of an aqueous solution in chemical contact with the anode and the cathode, characterized in that the current source contains a hygroscopic substance, which at least one Absorbs part of the water required as a solvent for the electrolyte. 2. Power source according to claim 1, characterized in that that the hygroscopic substance is at least partially the water-soluble base of the electrolyte forms. 3 «power source according to claim 2, characterized in that that the hygroscopic substance is mixed with the cathode material. 1. Power source according to claim 3, characterized in that that when the power source is activated, the cathode material is paste-like. 5. Power source according to one of claims 1 to 4, characterized gekennzei chnet that when the power source is activated, the water content of the electrolyte solution is practically complete originates from the action of the hygroscopic substance. 6. Power source according to one of claims 1 to 5, characterized in that the hygroscopic substance belongs to a group of substances comprising lithium chloride, zinc chloride, magnesium hydroxide and magnesium chloride. 0098S2 / 1539 7. Power source according to claim l, characterized by that the anode consists of zinc, the cathode contains manganese dioxide and the basic material of the electrolyte consists of a mixture of lithium chloride and ammonium chloride. 8. Power source according to claim 7 _S characterized ge ken n ζ eich η et that the base material of the electrolyte is mixed with the cathode material and a porous separator is arranged between the cathode and anode. 9. Use of the hygroscopic substance in a cell according to one of the preceding claims for absorbing and / or to replace the water that escapes from the electrolyte solution during operation, e.g. through evaporation. 009852/1839 '