JPH09237632A - Plate for lead acid battery and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase a discharge capacity at high rate discharge time by reforming a negative electrode active material and/or a positive electrode active material of a lead acid battery. SOLUTION: First, a water solution (pH equal acid point or less SiO2 ) of 35wt.% sulfuric acid concentration saturating Na2 SO4 is prepared. In this solution, SiO2 of 10 to 20nm grain size is immersed for an hour. Lignin and barium sulfate are compounded in lead powder, to be kneaded by dilute sulfuric acid and the SiO2 contained sulfuric acid water solution, a paste state negative electrode active material is prepared. A collector formed by a lattice unit of lead alloy is charged with this paste state negative electode active material, to be left (ageing) as undried at 80 deg.C for 24 hours in the nitrogen atmosphere, an unformed negative plate is formed. NaHSO4 may be used in place of Na2 SO4 .

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cathode plate that contributes to increasing the high rate discharge capacity of a lead storage battery and a method for producing the same, and more particularly to an additive to be added to a pasty active material.

[0002]

2. Description of the Related Art Lignin and barium sulfate are used as additives for lead-acid battery active materials. Since lead sulfate, which is a product of the discharge reaction of a lead storage battery, exhibits almost no electronic conductivity or ionic conductivity, it is necessary to secure or increase the place where the active material reacts with sulfate ions during discharge. Lignin contributes to the promotion of the reaction between the active material and sulfate ion from the standpoint of preventing coarsening of the active material particles, and barium sulfate from the viewpoint of increasing the surface area of the active material particles. Further, from the viewpoint of increasing the conductivity of the active material, a method has been attempted in which the active material contains conductive materials such as titanium carbide and titanium nitride which are resistant to corrosion. Since these lead sulfates have almost no electron conductivity, they contribute as a conduction aid.

[0003]

The additive of the above active material acts effectively in a low rate discharge of about 0.3C. However, at a high rate discharge of about 3 C, there was a problem that the supply of sulfate ions that react with the active material from the electrolytic solution was delayed and the discharge capacity was greatly reduced. The problem to be solved by the present invention is to improve the additive of the negative electrode active material and / or the positive electrode active material of the lead storage battery to increase the discharge capacity during high rate discharge.

[0004]

In order to solve the above-mentioned problems, a lead-acid battery electrode plate according to the present invention has a sulfate ion supply source necessary for a discharge reaction in a cathode active material and / or an anode active material. Not only from the electrolyte but also from the cathode active material and / or
Alternatively, the sulfate ion can be supplied also from the anode active material. That is, it is characterized in that both the acid-resistant metal oxide and the sulfate ion are present in the active material in the electrochemically bound state. Examples of the acid-resistant metal oxide include SiO ₂ , TiO ₂ , Al ₂ O ₃ and C.
_{aO, SnO 2, MnO 2,} Co 2 O 3 or the like can be suitably used. These metal oxides may be used alone or in combination of two or more. The method for producing a lead-acid battery electrode plate according to the present invention is a method for producing a lead-acid battery electrode plate in which a current collector made of lead-lead or a lead alloy is filled with a paste-like active material and aged in an undried state, wherein the paste The paste-like active material is characterized in that an acid-resistant metal oxide and a sulfate ion are contained in the paste-like active material, and both of them in an electrochemically bound state are present in the paste-like active material. As a result, it is possible to manufacture without increasing the number of manufacturing steps such as a lead storage battery assembling step.

In particular, the cathode plate for solving the above-mentioned problems is characterized in that the acid-resistant metal oxide and the sulfate ion, which are electrochemically bound to each other, have a concentration of M at a pH below the isoacid point of SiO _{2. 2} SO ₄ or MHSO ₄ (M: alkali metal)
SiO ₂ is dipped in a sulfuric acid aqueous solution containing Si
The particle size of O ₂ is more preferably 20 nm or less.
Acid-resistant metal oxides such as SiO ₂ are positively charged in an aqueous solution having a concentration having a pH equal to or lower than its isoacid point. as a result,
A force acts to keep the acid-resistant metal oxide particles such as SiO ₂ electrically neutral, and anions are electrochemically bound to the surfaces of the acid-resistant metal oxide particles such as SiO ₂ . That is, in the sulfuric acid aqueous solution containing M ₂ SO ₄ or MHSO ₄ (M: alkali metal), sulfate ions are bound to the surface of acid-resistant metal oxide particles such as SiO ₂ . As described above, the acid-resistant metal oxide such as SiO ₂ combined with sulfate ions acts as a source of sulfate ions in the cathode active material and / or the anode active material, so that the high rate discharge capacity can be increased. The isoacid point is the pH at the boundary where the oxide behaves as an acid or a base depending on the pH of the solution.

A method for manufacturing a cathode plate for a lead storage battery according to the present invention is a method in which a current collector made of lead or a lead alloy is filled with a paste active material and aged in an undried state. It is is contained SiO _2, the SiO _2,
It is characterized in that it is preliminarily immersed in a sulfuric acid aqueous solution containing M ₂ SO ₄ or MHSO ₄ (M: alkali metal) at a concentration showing a pH not higher than the isoacid point of SiO ₂ . It is more preferable that the sulfuric acid concentration of the sulfuric acid aqueous solution in which the SiO ₂ is immersed is set to 30% by weight or more.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described below. (Production of Cathode Plate) First, 50 g of a sulfuric acid aqueous solution saturated with Na ₂ SO ₄ and having a sulfuric acid concentration of 35% by weight is prepared. In this solution, a particle size of 10
Soak 10 g of 20 nm SiO ₂ for 1 hour. 6 kg of lignin for 3 kg of lead powder containing 70-80% by weight of lead monoxide
g, and 30 g of barium sulfate are mixed, and this is kneaded with 300 g of dilute sulfuric acid having a concentration of 35% by weight and the above-mentioned aqueous solution of sulfuric acid containing SiO ₂ to prepare a pasty cathode active material. About 25 g of the above-mentioned paste-like cathode active material is used as a lead alloy grid (70 mm × 4
It is filled in a current collector made of 0 mm × 3 mm) and left unripened in a nitrogen atmosphere at 80 ° C. for 24 hours (aged) to obtain an unformed cathode plate. When NaHSO ₄ is used instead of Na ₂ SO ₄ , the unformed cathode plate is obtained in the same manner as above.

Another example of the embodiment of the present invention will be described below. (Production of Anode Plate) First, 50 g of dilute sulfuric acid having a concentration of 35% is prepared as an aqueous solution containing sulfate ions. This dilute sulfuric acid has a particle size of 100 nm
90 g of the following SiO ₂ is immersed for 0.5 hours. And
3 kg of lead powder containing 70 to 80% by weight of lead monoxide is kneaded with 300 g of the dilute sulfuric acid and the dilute sulfuric acid containing SiO ₂ to prepare a pasty anode active material. Next, about 25 g of the above-mentioned paste-like positive electrode active material was added to a lead alloy grid (40 mm × 70 mm).
A undried electrode plate was prepared by filling a collector made of (3 mm). This undried electrode plate is left to stand at 80 ° C. for 24 hours in a nitrogen atmosphere, and then left to stand (aged) in a nitrogen atmosphere at 80 ° C. for 24 hours to be an unformed anode plate.

[0009]

EXAMPLES Two cathode plates manufactured by the manufacturing method described in the above embodiment of the invention and an anode plate manufactured by a conventional method (not by the manufacturing method described in the embodiment of the invention) (having the same dimensions as the cathode plate). ) A lead storage battery having a rated capacity of 4Ah-2V (discharging capacity of 4Ah when discharged at a rate of 20 hours from a fully charged state) was assembled by combining three sheets (Example 1). For comparison, an unformed cathode plate was prepared in the same manner as in Example 1 except that the above-mentioned SiO ₂ -free paste-like cathode active material was prepared. The same 4Ah-2V lead-acid battery as above was assembled by combining two of these cathode plates and three anode plates (having the same dimensions as the cathode plate) manufactured by a conventional method (conventional example). Further, two anode plates manufactured by the manufacturing method described in the embodiment of the invention and a cathode plate (same size as the anode plate) manufactured by a conventional method (not by the manufacturing method described in the embodiment of the invention) 3 The sheets were combined to assemble a 4Ah-2V lead acid battery (Example 2). Further, a battery was manufactured under the same conditions as in Example 2 except that TiO ₂ was used instead of SiO ₂ in Example 2 (Example 3). Further, in Example 2, SiO
_A battery was manufactured under the same conditions as in Example 2 except that Al ₂ O ₃ was used instead of ₂ (Example 4). 40 ± 5 ℃ for each lead acid battery
Was charged at a constant current of 0.4 A for 10 hours. Then, the following three types of charge / discharge tests were carried out.

(1) Each lead acid battery is set to 1 at 25 ± 2 ° C.
It was discharged to a final voltage of 1.4 V with a constant current of 2 A (3 C). FIG. 1 shows the change over time in the voltage during discharge. In Example 1 according to the present invention, it takes 1 time to reach the final voltage.
It is 4.3 minutes, which is one minute longer than 13.3 minutes of the conventional example. The time required to reach the final voltage of Example 2 was 15.3 minutes, the time required to reach the final voltage of Example 3 was 14.9 minutes, and the final voltage was reached to reach the final voltage of Example 2. The time was 14.7 minutes. Therefore, it can be understood that the battery of the present invention has a long discharge duration and a large discharge capacity even at a high rate discharge as compared with the conventional battery.

(2) Each lead-acid battery is discharged at a constant current of 12 A (3 C at 25 ± 2 ° C. to a final voltage of 1.4 V)-(constant current of 2.45 V (limit current 1.2 A)).
The battery was subjected to a charge / discharge cycle test in which (time charge)-(1 hour rest) was repeated, and the relationship between the charge / discharge cycle and the discharge capacity was investigated. As shown in FIG. 2, in the conventional example, the life is reached at 120 to 130 cycles, whereas in the examples, a life of 290 cycles or more is achieved, and in some cases, the life is not reached even after 300 cycles. It can be understood that the battery life is long even if high-rate discharge is repeated.

(3) In the manufacture of the battery of Example 1, S
The same charge / discharge cycle test as in (2) above was carried out by changing the sulfuric acid concentration of the sulfuric acid aqueous solution in which io ₂ was immersed, and the relationship between the sulfuric acid concentration and the charge / discharge cycle life was investigated. In addition, Si
Similar tests were carried out by changing the particle size of O ₂ . As shown in FIG. 3, when the concentration of the sulfuric acid aqueous solution showing the pH of the isoacid point of SiO ₂ (0.1% by weight) or more, the charge / discharge cycle life at high rate discharge becomes longer as the concentration of the sulfuric acid aqueous solution becomes higher. It can be understood that, when the concentration is 30% by weight or more, the life becomes almost constant. Further, it can be understood that the life is further extended when the particle diameter of SiO ₂ is 20 nm or less.

In this embodiment, the acid-resistant metal oxide is contained in only one of the cathode and the anode, but it may be contained in both. In addition, in this example, as the acid-resistant metal oxide, only SiO ₂ was used for the cathode plate, and only SiO ₂ , TiO ₂ , and Al ₂ O ₃ were used for the anode plate. However, for other acid-resistant metal oxides and cathode plates, for example, TiO ₂ , Al ₂ O ₃ , Ca
Even if O, SnO ₂ , MnO ₂ , Co ₂ O ₃ or CaO, SnO ₂ , MnO ₂ , Co ₂ O ₃ or the like is used for the anode plate, substantially the same effect as this embodiment can be obtained. Further, not only these oxides are used alone, but also when two or more kinds thereof are used in combination, substantially the same effect as in the present embodiment can be obtained.

[0014]

As described above, the electrode plate for a lead storage battery according to the present invention contributes to increase the capacity of the lead storage battery in high rate discharge. Further, it also contributes to the extension of the life of the lead storage battery in the repetition of high rate discharge. In the production of the cathode plate, when the sulfuric acid concentration of the sulfuric acid aqueous solution in which SiO ₂ is immersed is set to 30% by weight or more, the life becomes almost constant. In addition, SiO
_{Even when} the particle diameter of ₂ is 20 nm or less, the life can be extended. If the sulfuric acid concentration of the sulfuric acid aqueous solution for dipping SiO ₂ is 30% by weight or more and the particle size of SiO ₂ is 20 nm or less, the life can be further extended.

[Brief description of drawings]

FIG. 1 is a curve diagram showing a change over time in voltage when a lead storage battery is discharged.

FIG. 2 is a curve diagram showing a relationship between a charge / discharge cycle and a discharge capacity of a lead storage battery.

FIG. 3 is a curve diagram showing the relationship between the sulfuric acid concentration of an aqueous sulfuric acid solution in which SiO ₂ is dipped and the SiO ₂ particle diameter and the charge / discharge cycle life in the production of a cathode plate.

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[Procedure amendment]

[Submission date] October 9, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claim 2

[Correction method] Change

[Correction contents]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0004

[Correction method] Change

[Correction contents]

[0004]

In order to solve the above-mentioned problems, a lead-acid battery electrode plate according to the present invention has a sulfate ion supply source necessary for a discharge reaction in a cathode active material and / or an anode active material. Not only from the electrolyte but also from the cathode active material and / or
Alternatively, the sulfate ion can be supplied also from the anode active material. That is, it is characterized in that both the acid-resistant metal oxide and the sulfate ion are present in the active material in the electrochemically bound state. Examples of the acid-resistant metal oxide include SiO ₂ , TiO ₂ , Al ₂ O ₃ and S.
_{n O 2, MnO 2, Co} 2 O 3 or the like can be suitably used. Even if each of these metal oxides is used alone,
You may use together 2 or more types. The method for producing a lead-acid battery electrode plate according to the present invention is a method for producing a lead-acid battery electrode plate in which a current collector made of lead-lead or a lead alloy is filled with a paste-like active material and aged in an undried state, wherein the paste The paste-like active material is characterized in that an acid-resistant metal oxide and a sulfate ion are contained in the paste-like active material, and both of them in an electrochemically bound state are present in the paste-like active material. As a result, it is possible to manufacture without increasing the number of manufacturing steps such as a lead storage battery assembling step.

[Procedure 3]

[Document name to be amended] Statement

[Correction target item name] 0013

[Correction method] Change

[Correction contents]

In this embodiment, the acid-resistant metal oxide is contained in only one of the cathode and the anode, but it may be contained in both. In addition, in this example, as the acid-resistant metal oxide, only SiO ₂ was used for the cathode plate, and only SiO ₂ , TiO ₂ , and Al ₂ O ₃ were used for the anode plate. However, for other acid-resistant metal oxides and cathode plates, for example, TiO ₂ , Al ₂ O ₃ , Sn
_{O 2, MnO 2, Co 2} O 3, For example for the anode plate Sn
Even if O ₂ , MnO ₂ , Co ₂ O ₃ or the like is used, substantially the same effect as in this embodiment can be obtained. Further, not only these oxides are used alone, but also when two or more kinds thereof are used in combination, substantially the same effect as in the present embodiment can be obtained.

Claims (8)

[Claims] 1. An electrode plate for a lead storage battery, which comprises an acid-resistant metal oxide and a sulfate ion, and the both of which are in an electrochemically bound state are present in an active material. 2. An acid-resistant metal oxide is SiO ₂ , TiO ₂ ,
The electrode plate for a lead storage battery according to claim 1, which is at least one selected from Al ₂ O ₃ , CaO, SnO ₂ , MnO ₂ , and Co ₂ O ₃ . 3. An acid-resistant metal oxide and a sulfate ion, which are electrochemically bound to each other, have a p below the isoacid point of SiO _2.
The lead plate for a lead storage battery according to claim 1, wherein the lead plate is a cathode plate, which is SiO ₂ immersed in an aqueous sulfuric acid solution containing M ₂ SO ₄ or MHSO ₄ (M: alkali metal) at a concentration showing H, and the plate is a cathode plate. 4. The cathode plate for a lead storage battery according to claim 3, wherein the particle size of SiO ₂ is 20 nm or less. 5. A method for producing an electrode plate for a lead storage battery, wherein a current collector made of lead or a lead alloy is filled with a paste-like active material and aged in a non-dried state. And a sulfate ion, both of which are present in an electrochemically bound state are present in the paste-like active material, a method for producing a lead storage battery electrode plate. 6. An immersion treatment in an aqueous solution containing a sulfate ion at a concentration at which the acid-resistant metal oxide and the sulfate ion in the electrochemically bound state have a pH below the isoacid point of the acid-resistant metal oxide. It is the said metal oxide which was said, The manufacturing method of the polar plate for lead acid batteries of Claim 5 characterized by the above-mentioned. 7. The acid-resistant metal oxide is SiO ₂ , and the aqueous solution containing sulfate ions is M ₂ SO ₄ or MHSO ₄ (M:
The method for producing an electrode plate for a lead storage battery according to claim 6, wherein the electrode plate is a cathode plate, which is an aqueous solution of sulfuric acid containing an alkali metal). 8. The method for producing an electrode plate for a lead storage battery according to claim 7, wherein the sulfuric acid concentration of the sulfuric acid aqueous solution is 30% by weight or more.