JPS6211455B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing a solid state electrode for a storage battery cell formed from an active material consisting of a mixture of crystalline and polycrystalline lead dioxide.

The structure and operation of cells is well known. The cell is
Both primary and secondary batteries are electrochemical devices consisting of two plates of conductive material immersed in an electrolyte. While primary batteries generate electrical potential and irreversibly convert chemical energy into electrical energy, secondary batteries have a reversible function, converting chemical energy into electrical energy and vice versa. can be converted into chemical energy. Secondary batteries are generally more commonly referred to as "electricity storage cells."

When a storage cell provides electrical energy, the cell is said to be "discharging" and converting chemical energy to electrical energy. Also, when supplying electrical energy to a storage cell, the process is reversed and the cell is "charging".
It is called.

Two or more cells connected in series or in parallel constitute a battery, and a battery made by connecting several electricity storage cells is known as an electricity storage battery. 2 for the storage battery
There are several types, one of which is a lead-acid type battery or simply a lead battery, and the other is a nickel-alkaline type battery or an Edison type battery, or what is commonly called an alkaline battery. It is the former type of battery that the present invention is concerned with.

A lead-acid battery cell consists of a lead oxide anode plate and a sponge lead cathode plate, which are immersed in a dilute solution of sulfuric acid as the electrolyte. The active material of each plate is the part that undergoes chemical changes when electricity flows into the battery. The active material is supported on a frame or grid of pure lead or a lead alloy, such as an alloy of lead and antimony, which serves the dual function of supporting the active material and conducting electrical current.

The charge and discharge cycle in a typical lead-acid type battery can be described by the following reversible reaction.

Charge Discharge PbO ₂ +2H ₂ SO ₄ +Pb2PbSO ₄ +2H ₂ O Anode Plate Cathode Plate The active material on the anode plate is a cutlet-colored porous lead oxide, whereas the active material on the cathode plate is in pure form. It is a gray porous lead sponge.

The performance of lead-acid batteries currently available on the market is limited, and various attempts and proposals have been made to improve this. That is, the improved charging and discharging characteristics of these batteries, the increased current discharge rate, and the reduced internal resistance of the cells in the batteries are among the many properties that have received considerable attention from prior art researchers in this field. It's just a department. To improve the overall performance of cells and devices incorporating them, some researchers have focused on electrodes, while others have proposed various electrolytes.

U.S. Pat. No. 2,933,547 describes a battery made from a plurality of solid state cells consisting of silver and zinc electrodes and a solid membrane of solvated cation exchange resin interposed between these electrodes.

U.S. Pat. No. 3,468,719 discloses a solid-phase ion conductor made from a polycrystalline material whose lattice structure consists of a combination of aluminum and oxygen ions and sodium ions that move relative to the crystal lattice under the influence of an electric field. The body is described. This material has been used as a half-cell separator in battery construction, as described in more detail in Example 3 of this patent.

U.S. Pat. No. 3,499,796 describes a pair of cation-exchange relationships between an electron-conducting and a cation-conducting crystalline material separated by a cation-conducting but electron-nonconducting crystalline material. A ceramic sandwich and an apparatus using the same are described.

U.S. Patent No. 3709820 specifies 7, 7, 8,
An organic solid electrolyte is described that is a crystalline electron donor-acceptor complex consisting of ionic crystals of 8-tetracyanoquinodimethane, an aromatic amine, and a liquid impregnated in the ionic crystal lattice. The electrolytes described in this patent can be used in capacitors to reduce their resistance.

U.S. Pat. No. 3,765,915 describes the use of polycrystalline ceramics of beta-alumina for use as electrolytes in the construction of sodium-sulfur cells or batteries.

The aforementioned patents are just some of the numerous patents representing research and activity developed in this field, but they describe the basic structure of a lead-acid battery and the cells that make it up. The basic structure of remains essentially unchanged. Today, as in decades past, lead-acid batteries are constructed using porous lead oxide as the active material in the anode plate, porous lead as the cathode plate, and dilute sulfuric acid as the electrolyte. It is made by connecting cells in series.

Accordingly, it is an object of the present invention to provide improved energy storage cells and energy storage devices made from cells of this type.

Another object of the invention is to obtain an electrical storage battery in which the active material in the anode is a unique material made from crystalline and polycrystalline lead oxide.
In this specification, in order to distinguish a battery consisting of this type of cell from a conventional lead-acid battery,
We will call it a "lead-crystal" battery.

The foregoing and other objects of the present invention will be readily understood from the following detailed description, taken in conjunction with the accompanying drawings, which form a part of this specification.

According to the present invention, it is possible to obtain a power storage cell in which the active material on the power storage cell anode is a mixture of crystalline and polycrystalline lead dioxide (PbO ₂ ). That is, a mixture of lead and cadmium is first deposited as a uniform adhesive layer on a carrier plate coated with lead, an alloy of lead and antimony, or a suitable inert non-conducting material. or by any other convenient method. The mixture of lead and cadmium can be deposited on the carrier plate by hot spraying, the so-called powder or gold method or by electrodeposition methods, which methods will be described in the detailed description of the invention below.

As previously described, the carrier plate coated with lead and cadmium is then immersed in a container containing a dilute solution of sulfuric acid as an electrolyte and a lead plate or sheet serving as a cathode, and the carrier plate is then exposed to a power source. Connect to the positive terminal and connect the lead sheet to the negative terminal of the power supply. Passing an electric current through these carrier plates and lead sheets causes oxidation of the lead in the lead-cadmium layer to lead dioxide in crystalline or polycrystalline form, while the cadmium reacts with the sulfuric acid. It forms cadmium sulfate and is deposited as a sponge on lead sheets. The carrier plate is then removed from the solution, washed clean with water and dried.

The three carrier plates made as described above are then immersed in a second container containing a dilute solution of sulfuric acid, and the middle carrier plate is connected to the positive terminal of one power supply, while the other two Connect the carrier plate to the negative terminal of its power supply. When a current is passed, the central carrier plate becomes positively charged and the lead dioxide remains unchanged, while the lead oxide on the other two carrier plates is reduced to lead and becomes negatively charged.

When the power is turned off after a few minutes, the electromotive force inside the cell is
It drops from 2.9V to about 2.4V and then remains essentially constant at this level. In this way, the cell is charged and stores energy for later discharge.

Three or more such cells can be connected in series to form the lead-crystal battery of the present invention.

In the present invention, unexpectedly, the performance of the energy storage cell is significantly improved by providing the cell with a unique anode plate containing crystalline and polycrystalline lead oxide in the form of PbO ₂ as the active material. I found out that it is possible. For this reason, lead-crystal batteries made from such cells exhibit superior performance compared to conventional lead-acid batteries.

Although the following description will describe the invention in detail with particular reference to the construction of energy storage cells and batteries made from these cells, there are other energy storage devices that can be constructed based on the principles described herein. , these should not be construed as limiting the scope of the invention, as they are understood by and considered to be encompassed within this description.

Energy storage cells constructed in accordance with the present invention exhibit properties hitherto not available with conventional energy storage cells, and therefore devices obtainable by connecting such cells in series, e.g. It was found that the electricity storage battery exhibits superior performance compared to conventional lead batteries. Such performance improvements include, but are not limited to, lower internal resistance, higher activity, lower sulfation, improved charging and discharging properties, increased storage capacity, increased charging rate, and higher emf per cell.

The unique active material made by the method of the present invention is based on crystalline and polycrystalline lead oxide (PbO ₂ ), with lead having its highest valence of 4.

As used herein, the term polycrystalline refers to a collection of single crystals of lead dioxide in which the single crystals are in various stages of growth and development. The active material of the invention is therefore a mixture of single crystals of PbO ₂ and the aforementioned polycrystalline aggregates.

According to one embodiment of the present invention, and with particular reference to FIG. The prepared carrier plate 1 is immersed in dilute sulfuric acid (electrolyte) in a container 3. The carrier plate used in this embodiment is conveniently a foil made of an alloy of lead and antimony and approximately 0.2 mm thick, although the thickness of the carrier plate will depend on the specific construction and intended use of the storage device. You can change it somewhat.

Before the carrier plate 1 is immersed in the sulfuric acid solution, a hotmelt of lead and cadmium is sprayed onto the surface of the foil by a conventional spray gun or other suitable spraying equipment, so as to uniformly coat both sides of the foil with lead and cadmium. Deposit an adhesive layer. A reducing gas, for example hydrogen, is used when spraying the hotmelt onto the surface of the foil, and the spraying is discontinued when the thickness of the deposited layer reaches approximately 0.5 mm on each side.
This thickness may also vary somewhat depending on the specific construction of the power storage device, resistance requirements, and intended use.
Generally, the thickness of the Pb-Cd layer on both sides of the foil is approximately 0.1
~2mm, preferably about 0.5-1.2mm, optimally about 1
It can be changed to mm.

Pb-Cd melt is made by coating a cadmium wire with a thickness of approximately 1 mm with lead using electroplating or plating so that the weight ratio of lead to cadmium is 1:1, and then combing the coated wire to remove lead and cadmium. The molten alloy is sprayed onto the surface of the foil as described above at a temperature higher than the melting point of Pb--, but lower than the temperature at which the specific alloy of lead and antimony from which the carrier plate is made is melted to a significant extent. Causes sintering of Cd.

In order to improve the adhesion of the Pb-Cd layer to the surface of the carrier plate 1, the carrier plate (foil) is first sandblasted for several minutes to roughen its surface and the sintered Pb-Cd mixture is applied to the surface of the foil. It can also be made to adhere sufficiently to the It is to be understood that the terms "foil", "carrier plate" and "collector plate", which are used interchangeably herein, refer to this Pb--Sb carrier plate.

Returning now to FIG. 1, it shows that a material made of non-conductive material such as glass, plastic,
A container 3 is shown containing dilute sulfuric acid (electrolyte) having almost the same specific gravity as the sulfuric acid used in conventional lead-acid storage batteries. The container 3 also contains a lead plate or sheet 5 used as a cathode.
will be established. The collector plate or carrier plate 1 made as described above is immersed in an electrolyte as shown in FIG. Connected. Although one or more carrier plates can be immersed in the electrolyte and suitably connected to a source of electromotive force, for simplicity the invention will be described in the case of manufacturing only one anode plate. .

As mentioned above, when closing the circuit, the
Cadmium from the Pb-Cd layer reacts with sulfuric acid to form cadmium sulfate, and this cadmium sulfate is deposited on the lead sheet 5 as a porous spongy body. Hydrogen gas bubbles appear on the surface of the cathode, and oxygen rapidly and continuously combines with lead to form lead dioxide (PbO ₂ ) in the form of crystalline and polycrystalline forms. Since the generation of the active material is completed within a few minutes, the carrier plate is removed, cleaned and dried, and is ready for use in constructing the lead-crystal battery or cell of the present invention.

Lead dioxide crystalline and polycrystalline active materials are dark brown to black materials that are hard, uniform, highly porous, and have extremely low internal resistance.

When producing carrier plates with crystalline and polycrystalline lead dioxide as active material, it is essential to form this active material that the Pb-Sb plate is coated with sintered Pb-Cd. It is a condition. Therefore, during sintering or hot spraying on the carrier plate in this embodiment of the invention, Pd--Cd
Care must be taken to avoid the formation of alloys. The presence of Cd in the sintered body also indicates that Cd is PbO ₂
This is an essential condition because it assists or promotes the formation of crystals and polycrystals. Furthermore, it must be noted that although the cadmium reacts with the sulfuric acid in vessel 3 to form cadmium sulfate and is removed from this vessel, traces of cadmium nevertheless remain in the active material. It won't happen.

To construct a lead-crystal cell according to the present invention,
Three identical carrier plates 1 made by the method described above
a, 1b and 1c in a container 9 as shown in FIG.
immerse in it. The construction of the container 9 is similar to that of a lead-acid battery and contains the dilute sulfuric acid normally used in these batteries. Carrier plates 1a and 1
c are connected by a conductor 11 and connected by a conductor 13 to the negative terminal of a 3V power supply 15, for example a battery, a battery charging device, etc., while the carrier plate 1b is connected by a conductor 17 to the positive terminal of the power supply 15. Ru. When the circuit is closed in this way, the carrier plate 1a
PbO ₂ on and 1c is reduced to Pb and these carrier plates become negatively charged, while carrier plate 1
PbO ₂ on b remains chemically unchanged and becomes positively charged. The lead plate therefore acts as a cathode and the lead dioxide plate acts as an anode.

When the power supply 15 is turned off a few minutes after the cell is fully charged, the electromotive force inside the cell decreases from 2.9V to approx.
It drops to 2.4V and remains virtually constant at this level. This charges the cell, storing energy to be released later.

If the cells manufactured as described above are connected in series, for example three in total, the number of cells and the carrier plates in each cell will vary, since the cells will have several carrier plates (usually 17 or 19) connected in parallel. A lead-crystal battery containing 51 or 57 pieces is formed depending on the number of pieces. However, more than two cells, for example six cells, may optionally be connected in series.

Lead-crystal batteries incorporating the unique features of the present invention exhibit superior performance compared to lead-acid batteries. In other words, the internal resistance is low, so 51 or
Lead made of 57 carrier plates - The crystal battery is lead -
It can receive about 10 to 15 times more current than an acid battery. Lead-crystal batteries can therefore be charged much faster than lead-acid batteries. Similarly, the discharge rate of lead-crystal batteries is also significantly improved because lead-crystal batteries can deliver current at a significantly accelerated rate than lead-acid batteries.

FIG. 3 compares the discharge curve of a lead-crystal cell made according to the present invention with the discharge curve of a typical lead-acid cell. The solid line in FIG. 3 shows the discharge curve of the lead-crystal cell, and the broken line shows the discharge curve of the lead-acid cell. Comparing both discharge curves, during the first 16 minutes,
That is, during about 80% of the discharge cycle, the emf of the lead-crystalline cell remains constant, and then after 2.32V
It shows a very slight drop from 2.1V to about 2.3V, whereas the emf of the lead-acid cell decreases at a steady rate over the same period, dropping from 2.1V to about 2.0V. This difference becomes noticeable in batteries that combine such cells, indicating that lead-crystal batteries are able to maintain their emf at a higher level than lead-acid batteries, and therefore exhibit superior performance. ing.

Additionally, the lead-crystal batteries of the present invention exhibit approximately 25-30% higher capacity than conventional lead-acid batteries.
In addition, lead-crystal cells can be charged and discharged much more completely than lead-acid cells, with no after-reactions or self-charging, and therefore lead-crystal batteries can be charged and discharged much more completely than lead-acid cells; - Shows greater storage capacity than acid batteries. Batteries made according to the principles described herein are approximately
Generates a high electromotive force of 0.1~0.2V.

In the above explanation, sintered lead and cadmium are applied to the surface of the collector plate by hot spraying to form a uniform layer of Pb-Cd on the collector plate.
An adhesive layer was deposited. Two other methods of depositing a Pb--Cd layer on the surface of a Pb--Sb carrier plate will now be described.

In another embodiment of the invention, the particle size is about 100
~500 micron soft lead and cadmium 1:1
The granules of the mixture are dissolved in a suitable organic liquid such as methanol or ethanol to form a paste, which is then deposited on the surface of the carrier plate through a suitable sieve. After that, the methanol is evaporated, the carrier plate is dried, and the Pb-Cd is
Sintering is carried out in a press at a temperature of 400° C. for about 3 seconds. Even in this case, the temperature and pressure during sintering must be carefully regulated to prevent the formation of Pb--Cd alloys.

The thickness of the Pb--Cd layer on the carrier plate can be adjusted by choosing a suitable mesh sieve and by uniformly depositing the appropriate amount of paste on the surface of the carrier plate. In this way, approximately 0.5 mm thick Pb--Cd layers can be deposited on both sides of the carrier plate.

After depositing the desired thickness of coating, the carrier plate is immersed in a container containing dilute sulfuric acid and a lead plate as described above with respect to FIG. Forms crystalline and polycrystalline lead dioxide (PbO ₂ ). Since the cadmium from the Pb-Cd layer reacts with sulfuric acid and is deposited in the form of CdSO ₄ , the cadmium can be recovered from this and reused, then using a carrier plate as described above with respect to Figure 2. Used to construct lead-crystalline cells.

In another embodiment of the invention, a hard compact alloy of lead and cadmium is deposited on the carrier plate by electroplating in a borofluoride bath. That is, an electrode made of an alloy of lead and antimony as a cathode and an electrode made of a 1:1 alloy of lead and cadmium as an anode are immersed in a borofluoride bath having the following composition.

Lead borofluoride [Pb (BF ₄ ) ₂ ]
3.37Kg (119oz) Metallic Lead (Pb) 1.84Kg (65oz) Boric Acid (HBF ₄ ) 28.3g (1.0oz) Boric Acid 226.8g (8.0oz) Cadmium Borofluoride [Cd (BF ₄ )]
921.4 g (32.5 oz) Cadmium metal (Cd) 340.2 g (12.0 oz) Ammonium fluoride 226.8 g (8.0 oz) Water 3.785 (1 gal) Next, connect both electrodes to the positive and negative terminals of a 5V power supply. After time electrolysis, a uniform layer of cadmium and lead about 0.1 mm thick is deposited on both sides of the cathode. Then turn off the power, remove the cathode from the bath, wash thoroughly with water and dry.

To produce three carrier plates with crystalline and polycrystalline lead dioxide on the surface, three cathode carrier plates made in this way were immersed in a dilute sulfuric acid electrolyte and as described above with respect to Figure 1. Treat it like work. The resulting carrier plate is then used to construct a lead-crystal cell as described above with respect to FIG.

As is apparent from the foregoing detailed description, the lead-crystal batteries of the present invention are significantly superior to lead-acid batteries. In addition to the several unique properties mentioned above, lead-crystal batteries are typically about 15 times smaller than lead-acid batteries of comparable size and capacity.
~30% lighter by weight and exhibits approximately 25-30% greater capacity than lead-acid batteries of comparable size and weight. Due to its significantly lower internal resistance and high activity, it can extract substantially large amounts of power in a fairly short period of time, making it suitable for use in vehicles requiring rapid acceleration, such as electric vehicles and trains and other electrical power sources. Particularly useful.

Also, lead-crystal batteries made in accordance with the present invention exhibit little or no sulfation. In practice, this means that these batteries can be discharged to a point close to zero emf. In contrast, sulfation is a rather uncommon phenomenon in lead-acid batteries, and therefore lead-acid batteries have an emf of about 1.5 to
Cannot be discharged above 1.8V. Further discharges result in almost reversible sulfation in the lead lattice holding the active material paste.

While the invention has been described and illustrated with certain specificity, it should also be noted that certain modifications may be made that are obvious from the foregoing description and thus fall within the spirit and scope of the invention. .

For example, instead of using a Pb--Sb carrier plate, an inert, non-conductive carrier plate made of a suitable plastic, such as polypropylene or cellulose material, is used, on which lead or lead and antimony is applied as described above. It is also possible to deposit mixtures of. Such a carrier plate weighs considerably less than a Pb--Sb carrier plate, so that the battery produced is also considerably lighter.

Furthermore, although the present invention has been described with respect to a Pb:Cd weight ratio of 1:1, this ratio can be varied to about 30 to 70% by weight, preferably about 45 to 55% by weight; Results are obtained when both components are used in equal weight ratios. When the amount of lead in the mixture is increased, for example 70% by weight, the Pb-Cd layer becomes softer.
When the cadmium component is high, for example 70% of the mixture, while the pores are low, the formation of
The Pb-Cd layer becomes hard and porous. The optimum hardness and optimum porosity of the Pb-Cd layer are 1:1 mixture.
It is obtained when the weight ratio of

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram illustrating a method of forming active bodies, ie, crystalline and polycrystalline lead oxides, according to the present invention. FIG. 2 is another explanatory diagram illustrating the formation of an anode plate, a cathode plate, and a cell made of these plates. FIG. 3 shows two curves comparing the discharge characteristics of a lead-crystalline cell made in accordance with the present invention with those of a conventional lead-acid type cell. In the figure, 1 is a carrier plate, 3 is a container, 5 is a lead sheet, 7 is a power source, 9 is a container, and 15 is a power source.

Claims (1)

[Scope of Claims] 1 (a) A carrier plate made of lead, an alloy of lead and antimony, or an inert non-conductive material coated with lead or an alloy of lead and antimony, containing lead and cadmium. (b) immerse the generated carrier plate in a container containing dilute sulfuric acid and a lead plate; (c) connect the carrier plate to the positive terminal of a power source and connect the lead plate to the negative terminal of the power source; (d) cadmium in the lead-cadmium layer is reacted with sulfuric acid to produce and precipitate cadmium sulfate on the lead plate, and at the same time - A method for producing solid electrodes for storage battery cells, in which lead in a cadmium layer is oxidized to produce a mixture of crystalline and polycrystalline lead dioxide in which lead is in its highest tetravalent state. 2 In step (a), a uniform adhesion layer of lead and cadmium is formed by spraying a hot melt mixture of lead and cadmium on the surface of the carrier plate in a reducing atmosphere to form an alloy of lead and cadmium on the surface of the carrier plate. A method for producing a solid-state electrode according to claim 1, wherein the solid-state electrode is formed by sintering a hot-melt mixture without sintering. 3. The method of claim 2, wherein the hot melt mixture contains about 30-70% by weight lead. 4. The method of claim 2, wherein the hot melt mixture contains about 45-55% by weight lead. 5. The method of claim 2, wherein the weight ratio of lead to cadmium in the hot melt mixture is about 1:1. 6 In step (a), a uniform adhesive layer of lead and cadmium is formed by making a relatively dilute paste of a mixture of lead and cadmium in a reducing organic liquid, depositing the paste on a carrier plate, and draining the solvent from the paste. 2. A method according to claim 1, wherein the method is formed by evaporation. 7. The method according to claim 6, wherein the reducing organic liquid is methanol. 8. The method according to claim 6, wherein the reducing organic liquid is ethanol. 9. The method of claim 6, wherein the lead and cadmium layer contains about 30-70% by weight lead. 10 The layer of lead and cadmium contains approximately 45 to 55% lead by weight.
7. The method according to claim 6, comprising: 11. The method of claim 6, wherein the lead to cadmium layer has a weight ratio of lead to cadmium of about 1:1. 12 The layer of lead and cadmium contains approximately 30 to 70% lead by weight.
The method according to claim 7, comprising: 13 The layer of lead and cadmium contains about 45 to 55% lead by weight.
The method according to claim 7, comprising: 14. The method of claim 7, wherein the lead to cadmium layer has a weight ratio of lead to cadmium of about 1:1. 15 The layer of lead and cadmium contains about 30 to 70% lead by weight
9. The method according to claim 8, comprising: 16 The layer of lead and cadmium contains approximately 45 to 55% lead by weight.
9. The method according to claim 8, comprising: 17. The method of claim 8, wherein the lead to cadmium layer has a weight ratio of lead to cadmium of about 1:1. 18 In step (a), a uniform adhesion layer of lead and cadmium is formed between two electrodes, a cathode made of an alloy of lead and antimony, and an anode made of lead and cadmium, and lead borofluoride, metallic lead, and borofusic acid. , immersed in an electrolytic bath containing boric acid, cadmium borofluoride, metallic cadmium, ammonium borofluoride, and water, the cathode and anode being connected to the negative and positive terminals of a power source, respectively, and electrical current passing through the electrodes. A method for producing a solid electrode according to claim 1, wherein the solid electrode is formed on the surface of the carrier plate by a plating method. 19. The method of claim 18, wherein the anode contains about 30-70% by weight lead. 20. The method of claim 18, wherein the anode contains about 45-55% by weight lead. 21. The method of claim 18, wherein the weight ratio of lead to cadmium in the anode is about 1:1.