RU2371815C2 - Ni-zn storage battery and method to produce active masses, mainly, for its electrodes - Google Patents

Abstract

FIELD: electrical engineering.

SUBSTANCE: nickel-zinc storage battery comprises housing accommodating interconnected electrodes place in electrolyte. Interconnected positive electrodes are fitted between negative electrodes and separated therefrom by separators. Every electrode consists of current conducting foil-like element with edge flanged along its perimetre. Active mass is built-up on foil side surfaces. Negative or positive electrode being produced, homogeneous mix of active mass consists of either binder and interlayer compound of zinc or nickel with graphite. Active mass outer surfaces support separators. Method of making active mass comprises separate production of interlayer compounds of zinc and nickel with graphite. For this mixes of zinc and nickel chlorides are preliminary heated to 85°C to 150°C. Then aforesaid surfaces are treated by 85%- to 95%-concentrated nitric acid for 1.5 to 5.0 and 2.0 to 6.0 h, respectively. Produced interlayer compounds are separately flushed to produce neutral reactions and dewatered. Dewatered compounds are, now, ground to finely produce negative or positive electrode.

EFFECT: higher reliability, specific capacity, lower weight and costs.

3 cl, 4 dwg, 2 ex

Description

The invention relates to the field of electrical engineering and can be used in the manufacture of nickel-zinc batteries.

Known from published application of the Russian Federation No. 93003473/07, cl. ⁶ H01M 4/24 of 01/20/1993, a nickel-zinc battery containing a housing, separators, an alkaline electrolyte, a negative electrode consisting of a current-conducting metal grating with a pressed-in layer of active mass of zinc powder with a binder, and a positive electrode in the form of a current-supplying nickel a lattice with an active mass pressed from it of nickel powder with a binder, and a method for producing an active mass for its electrodes, comprising mixing an organic binder - polymethyl methacrylate, depending on the purpose of the ele ctrode, with zinc-containing and nickel-containing components in the form of powders.

The disadvantages of this nickel-zinc battery are the ability to peel active masses from metal current-carrying gratings, the possibility of shorting the electrodes shortly due to the growth of dendrites during charging and uneven slow dissolution of zinc powder during discharge.

Closest in their technical essence to the proposed nickel-zinc battery and a method of manufacturing its electrodes are known from the patent of the Russian Federation No. 2232449, class. ⁷ H01M 10/30, 2002 a nickel-zinc battery containing a case filled with an alkaline electrolyte with negative electrodes located in the latter in parallel in the form of conductive elements with active masses pressed onto their surfaces, formed by a homogeneous mixture of organosilicon binder with zinc-containing and carbon-containing components, between which are placed positive polymer electrodes separated from them by polymer separators in the form of conductive elements with pressed on their surface active masses formed by a homogeneous mixture of an organosilicon binder with nickel-containing and carbon-containing components, and a method for producing an active mass for electrodes, mainly for a nickel-zinc battery, comprising forming a homogeneous mixture of a thermally curable organosilicon binder with pre-ground carbon-containing and, depending on purpose of the electrode, zinc-containing or nickel-containing components.

The disadvantages of the aforementioned battery and the method of manufacturing electrodes for it are the short life of the aforementioned nickel-zinc battery, comprising 100-200 charge-discharge cycles, crystallization on negative zinc electrodes in the form of large branched crystals - dendrites, capable of piercing the separators with their sharp “branches” and short circuit the positive electrodes, and the so-called "creep" due to periodic changes in the volume of active masses and their movement to the lower parts of the electrodes under the occurrence of gravity and uneven distribution of the electric potential over the electrode surface.

The aim of the invention is to increase reliability, specific capacity and increase the number of charge-discharge cycles.

The above objectives are achieved in that in a nickel-zinc battery containing a case filled with alkaline electrolyte with negative electrodes located in the latter in parallel in the form of conductive elements with active masses pressed onto the surface, formed by a homogeneous mixture of organosilicon binder with zinc-containing and carbon-containing components, between which are placed separated from them by polymer separators in parallel connected positive electrodes in the form of of conductive elements with active masses pressed onto their surface, formed by a homogeneous mixture of an organosilicon binder with nickel-containing and carbon-containing components, the conductive element of each electrode is made in the form of a thin-walled foil plate with an edge bent around the perimeter, zinc-containing and carbon-containing components of the active mass of the negative electrode are in the form of interlayer compounds of zinc with graphite, the nickel-containing and carbon-containing components of the active mass are positive of the second electrode — in the form of an interlayer connection of nickel with graphite, and the content of zinc and nickel in the interlayer compounds of the active masses of the negative and positive electrodes exceeds the graphite content in them by 2.75–4.75 and 2.8–4.2 times, respectively This polymer separators are fixed on the outer surfaces of the active masses, pressed onto thin-walled foil plates, bends of the bends of the edges of the latter, and in the method of producing the active mass for the electrodes, mainly for a nickel-zinc battery, including The use of a homogeneous mixture of an organosilicon binder with pre-ground carbon-containing and, depending on the purpose of the electrode, zinc-containing or nickel-containing components, graphite, zinc chloride and nickel chloride, respectively, are used as the carbon-containing, zinc-containing and nickel-containing components of the active masses, which, before mixing with the formation of the organosilicon binder, interlayer compounds of zinc or nickel with graphite, a mixture of zinc chloride with graphite and nickel chloride spruce, is subjected at a temperature of 85-150 ° C for 1.5-5.0 and 2.0-6.0 hours, respectively, to the separate effects of concentrated 85-95% nitric acid on said mixtures, after which the resulting interlayer compounds of zinc and nickel separately washed with graphite to obtain neutral wash liquid reactions and dehydrated, while the amount of zinc and nickel exceeds the graphite content in the interlayer compounds, respectively, 2.75-4.75 and 2.8-4.2 times.

In addition, the nickel-zinc battery can be equipped with auxiliary separators located between the main polymer separators.

The proposed method for producing an active mass for electrodes mainly for a nickel-zinc accumulator includes the separate production of interlayer compounds of zinc and nickel with graphite. To obtain an interlayer compound of zinc or nickel with graphite, mixtures of zinc chloride and nickel chloride with graphite are previously separately heated to a temperature of 85-150 ° C. Then, the aforementioned heated mixture of components is treated separately, respectively, for 1.5-5.0 and 2.0-6.0 hours with concentrated 85-95% nitric acid. The amount of zinc and nickel in their interlayer compounds with graphite exceeds the content of the latter in them by 2.75–4.75 and 2.8–4.2 times, respectively. The obtained interlayer compounds of zinc and nickel with graphite are washed separately until neutral reactions of the washed substances are obtained and dehydrated. The dehydrated interlayer compounds of zinc and nickel with graphite are then used respectively to obtain active masses intended for the negative or positive electrode. Obtaining the active masses of the electrodes is carried out immediately before pressing (applying) them to the side surfaces of the conductive elements of each electrode, made in the form of a thin-walled foil plate with an edge bent around the perimeter, by mixing the previously mentioned interlayer compounds with an organosilicon binder to obtain their homogeneous mixture.

The essence of the design of the Nickel-zinc battery is illustrated by drawings, where figure 1 schematically shows a General view of a Nickel-zinc battery in section; figure 2 is a fragment of a separator in axiometry; figure 3 is a cross section of figure 2 and figure 4 is a workpiece of a conductive element in the form of a plate of copper foil.

Nickel-zinc battery consists of a housing 1 filled with an alkaline electrolyte, in which negative 3 electrodes are connected in parallel with each other by terminal 2. Between negative 3 electrodes, positive 5 electrodes separated by polymer separators 4 are located, connected to each other by terminal 6. Each electrode consists of a conductive element in the form of a thin-walled plate 7 made of foil with an edge bent around the perimeter 8. An active mass 9 is pressed onto the lateral surfaces of the thin-walled plate 7 Depending on whether negative 3 or positive 5 electrodes are made, the active mass of the last 9 consists of a homogeneous mixture formed by an organosilicon binder corresponding respectively, with an interlayer compound of zinc or nickel with graphite. The content of zinc and nickel in the interlayer compounds of the active mass of negative 3 and positive 5 electrodes exceeds the content of graphite in them 2.75–4.75 and 2.8–4.2 times, respectively. On the outer surfaces of the active masses 9, polymer separators 4 are installed, which are fixed by the bends of the bends 10 with an edge 8 bent around the perimeter of the conductive element in the form of a thin-walled foil plate 7. As an organosilicon binder in a homogeneous mixture of active mass 9, polyorganylsiloxane or polyorganyldisiloxane can be used, which upon thermal or catalytic curing form insoluble polyorganylsiloxanes that have high adhesion to the metal of the conductive elements.

Specific examples of the method for producing the active mass, mainly for electrodes of a nickel-zinc battery:

Example 1. Previously to obtain used in the active mass of the negative electrode of the interlayer connection of zinc with graphite. 1000 g of graphite grade GE-1 is mixed with 2800 g of zinc chloride to obtain a homogeneous mixture. Concentrated 85-95% nitric acid is added to the resulting mixture and the mixture is maintained until complete dissolution of the treated homogeneous mixture. The resulting solution is heated to 140 ° C and incubated for 3 hours, and then crystallization of the obtained interlayer zinc-graphite compound in which the zinc content exceeds the graphite content by 3.5 is carried out for the next 3 hours at a temperature of 130 ° C. times. After crystallization, the interlayer compound of zinc with graphite is washed until neutral and wash water is removed within 2-3 hours. The dehydrated interlayer zinc compounds with graphite are then ground. Mixing the crushed interlayer zinc compound with graphite with an organosilicon binder, for example polyorganyl disiloxane to obtain a homogeneous mixture, which is the uncured active mass of the negative electrode, is carried out immediately before it is pressed (applied) to the side surfaces of the negative electrode conductive element. The uncured active mass deposited on the side surfaces of the conductive element, the negative electrode is then maintained to remove the solvent.

Example 2. Previously, to obtain used in the active mass of the positive electrode of the interlayer connection of Nickel with graphite 600 g of graphite grade GE-1 is mixed with 1800 g of Nickel chloride to obtain a homogeneous mixture. Concentrated 85-95% nitric acid and 1500 ml of distilled water are added to the resulting mixture and incubated for 4 hours at a temperature of 100 ° C. The amount of nickel in its obtained interlayer connection with graphite exceeds the amount of the latter by 3.8 times. The precipitated interlayer compound of nickel with graphite is then washed until the washings are neutral and the washings are removed. The dehydrated interlayer compound of nickel with graphite is then ground. Mixing the crushed interlayer connection of nickel with graphite with an organosilicon binder, for example polyorganylsiloxane to obtain a homogeneous mixture, is carried out immediately before it is pressed (applied) to the side surfaces of the conductive element, the positive electrode. The active mass deposited on the side surfaces of the conductive element of the positive electrode is then maintained to remove the solvent.

The proposed Nickel-zinc batteries and a method for producing active masses, mainly for its electrodes, can reduce their cost by eliminating the consumption of toxic materials such as lead, mercury or cadmium. The use of nickel-zinc batteries instead of lead ones can also reduce the weight and cost while improving the electrical and operational characteristics of the batteries.

Claims (3)

1. Nickel-zinc battery containing a case filled with alkaline electrolyte with negative electrodes located in the latter parallel connected in the form of conductive elements with active masses pressed onto their surfaces, formed by a homogeneous mixture of organosilicon binder with zinc-containing and carbon-containing components, between which are separated polymer Separators connected in parallel positive electrodes in the form of conductive elements with napressovann active masses formed on their surface, formed by a homogeneous mixture of an organosilicon binder with a nickel-containing and carbon-containing components, characterized in that the conductive element of each electrode is made in the form of a thin-walled foil plate with an edge bent around the perimeter, zinc-containing and carbon-containing components of the active mass of the negative electrode are in the form interlayer connection of zinc with graphite, nickel-containing and carbon-containing components of the active mass of the positive electrode - in in the form of an interlayer connection of nickel with graphite, while the content of zinc and nickel in the interlayer compounds of the active masses of the negative and positive electrodes exceeds the graphite content in them 2.75-4.75 and 2.8-4.2 times, respectively, and the polymer separators are fixed on the outer surfaces of the active masses, pressed onto thin-walled foil plates, by the bends of the bends of the edges of the latter. 2. The battery according to claim 1, characterized in that it is equipped with auxiliary separators located between the main polymer separators, mounted on the negative and positive electrodes along their perimeter. 3. A method of obtaining an active mass for electrodes, mainly for a nickel-zinc battery, comprising forming a homogeneous mixture of an organosilicon binder with pre-ground carbon-containing and, depending on the purpose of the electrode, zinc-containing or nickel-containing components, characterized in that as carbon-containing, zinc-containing and nickel-containing components of the active masses, respectively, use graphite, zinc chloride and nickel chloride, which before mixing with silicon organic binder for the formation of interlayer compounds of zinc or nickel with graphite, a mixture of zinc chloride with graphite and nickel chloride, is subjected at a temperature of 85-150 ° C for 1.5-5.0 and 2.0-6.0 hours, respectively, separate exposure concentrated 85-95% nitric acid to the above mixtures, after which the obtained interlayer compounds of zinc and nickel with graphite are washed separately to obtain neutral wash liquid reactions and dehydrated, while the amount of zinc and nickel exceeds the graphite content in the interlayer Connections respectively 2,75-4,75 and 2.8-4.2 times.

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