JP3414941B2 - Electrode plate for lead storage battery and method of manufacturing the same - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a lead storage battery electrode plate.

[0002]

2. Description of the Related Art Lead-acid batteries are used as automobile batteries because they are relatively inexpensive and have stable performance as secondary batteries. In recent years, they have been used as backups for power supplies for portable equipment and computers. It has also become popular as a power source. In recent years, the development of electric vehicles has been in the limelight as a measure to reduce the pollution of automobiles. In addition, cordless portable devices are being developed. In order to improve the performance of these lead-acid batteries, improvement of high rate discharge characteristics is a particular issue. The high rate discharge characteristics are largely controlled by the supply of the electrolytic solution to the active material. Lead-acid batteries have lead dioxide (PbO ₂ ) for the positive electrode, lead (Pb) for the negative electrode, and sulfuric acid (H ₂ S) for the electrolyte.
O ₄ ) aqueous solution is used. The reaction of the positive electrode is expressed by the formula (1),
The reaction of the negative electrode is as shown in equation (2).

[0003]

[Chemical 1]

As is apparent from the above reaction, the active material of both the positive electrode and the negative electrode is changed to lead sulfate (PbSO ₄ ) by the discharge reaction. When lead and lead dioxide are converted to lead sulphate, their volume increases approximately twice. Therefore, as the discharge reaction proceeds, the pores in the electrode plate are blocked by the precipitated lead sulfate, and the diffusion capacity of sulfate ions deteriorates. This leads to a decrease in battery voltage and a decrease in active material utilization rate. Also, this lead sulfate changes to lead dioxide at the positive electrode and lead at the negative electrode during charging, but if the electrolyte supply capacity into the electrode is poor, this reaction does not proceed smoothly and charging efficiency decreases. . In particular, the higher the current density and the higher the charge / discharge, the greater this effect.

As described above, the deterioration of the supply capacity of sulfuric acid into the electrode is a major problem for improving the high rate discharge characteristics and extending the life of the lead storage battery. As a measure for solving these problems, conventionally, a method of decreasing the packing density of the active material to form many voids for holding or diffusing the electrolytic solution in the electrode plate, or a powdery porous glass or A technique has been taken in which glass cotton woven with glass fibers is added to the electrode plate to improve the amount of electrolyte retained.

[0006]

The above-mentioned method of reducing the packing density can increase the amount of the electrolytic solution in the electrode plate, so that the high rate discharge characteristic is improved. However, voids are formed in the electrode plate, the bonding force between the active material particles is reduced, and the mechanical strength of the electrode plate is weakened. Repeated charging / discharging causes the active material to fall off significantly, resulting in a large decrease in life characteristics. There was a drawback. The method of adding powdery porous glass can improve the high rate discharge characteristics, but cannot improve the cycle life. On the contrary, the addition of glass cotton improves the cycle life, but does not significantly improve the high rate discharge characteristics.

The present invention solves such a problem and constructs an electrode plate capable of supplying abundant electrolyte solution to an active material without adversely affecting life characteristics, and has a long life excellent in high rate discharge characteristics. It is intended to provide a lead storage battery.

[0008]

The lead plate for a lead storage battery of the present invention is processed on the glass core material and the surface of the glass core material as a holding material for the electrolytic solution or a diffusion passage of sulfuric acid in the electrode plate.
And a fibrous porous glass having a porous layer formed therein . By using this electrode plate, the above-mentioned object can be achieved and a long-life lead-acid battery excellent in high rate discharge characteristics can be provided.

According to the method for producing a lead-acid battery electrode plate of the present invention , a glass core material and a precursor are contained in an active material mainly composed of lead powder.
The fibrous porous glass having a porous layer processed on the surface of the glass core material is mixed, and a paste made by kneading this with water and sulfuric acid is filled in a lead alloy current collector, and an aging step and The electrode plate is formed through the chemical conversion process. Further, the manufacturing method of the lead-acid battery electrode plate of the present invention, in the active material mainly containing lead powder ,
A glass core material and a multi-processed surface of the glass core material.
The porous Shitsuga la scan fibrous having a porous layer was mixed, which collector the organic polymeric resin was kneaded with a solution dissolved in a solvent paste made of lead alloy as a binder It is applied to, and then dried and formed into a polar plate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is characterized by containing a fibrous porous glass in an electrode plate. Of course, this fibrous porous glass shows acid resistance,
It excels in water absorption and is extremely suitable as an electrolyte holding material for lead-acid batteries. The fibrous porous glass used here is obtained by processing the surface of glass fiber into a porous shape. A fibrous porous glass having a large number of pores of 5 μm or less formed on the surface is preferable. Such fibrous porous glass has an electrolytic solution retention amount of 3 per unit weight as compared with conventional glass wool.
Improve by 0% or more.

The electrode plate containing an appropriate amount of the fibrous porous glass according to the present invention includes the electrolytic solution held by the pores of the porous structure formed by the mutual bonding of the particles and the porous structure of the glass fiber itself. The electrolytic solution held in the holes of the electrode is added, and a large amount of electrolytic solution is held in the electrode plate. Furthermore, since the porous glass fiber also functions as a diffusion passage of sulfuric acid from the surface of the electrode plate to the inside, diffusion of sulfuric acid from the electrolyte layer to the inside of the electrode plate is smoothly performed. Further, since the fibrous porous glass contributes to the formation of the porous structure of the electrode plate, the strength of the electrode plate is increased, and the active material is dropped off as seen in the conventional electrode plate simply by decreasing the packing density. Problems such as deterioration of discharge performance and reduction of cycle life can be avoided.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. Example 1 FIG. 1 is a sectional view of a single fiber of fibrous porous glass used in an example of the present invention, and FIG. 2 schematically shows a section of a positive electrode plate used in the example. First, as the raw material for the positive electrode or the negative electrode, lead powder containing 25% by weight of metallic lead and 75% by weight of lead monoxide (oxidization degree of 75%) was used, and the negative electrode was 2% by weight of barium sulfate and 1% by weight. Carbon powder, 0.5%
Lignin was added to prepare a mixture. 2% of the weight of the lead component in the lead powder was added to each of the raw materials of the positive and negative electrodes and uniformly mixed. Water and dilute sulfuric acid were added to this mixture and kneaded to form a paste. In addition, lead compounds such as red lead, basic lead sulfate, and lead dioxide powder may be added as an additive for the positive electrode, but the present invention is also applicable to such a case.

In this embodiment, a material obtained by dissolving the surface of glass fiber with hydrofluoric acid or the like to make it porous is used. FIG. 1 shows the structure of a single fiber of the fibrous porous glass. The fibrous porous glass 1 is composed of a glass core material 2 having a diameter of about 20 to 30 μm and a porous layer 3 on the surface processed into a porous shape. The fibrous porous glass 1 having such a structure maintains its strength by the core material and is not broken during paste kneading. If the glass fiber is made entirely porous up to the central portion, the strength of the fiber itself cannot be maintained and the glass fiber is broken during paste kneading.

Next, the above paste was filled in a casting grid made of a lead-calcium alloy, aged in a high temperature and high humidity according to a conventional method, and then subjected to chemical conversion to prepare a positive electrode plate and a negative electrode plate. In these steps, raw materials such as lead containing lead components in the active material mixture are converted into lead sulfate and basic lead sulfate by kneading with sulfuric acid and aging, and when these are positive plates due to chemical conversion. Is oxidized to lead dioxide, and in the case of the negative electrode is reduced to lead, resulting in positive and
It becomes the active material of the negative electrode. A battery of 2V and 2Ah with a positive electrode capacity regulation of 2V and 2Ah was prepared by using the above two positive electrode plates and three negative electrode plates with a mat-shaped separator made of glass fiber interposed therebetween and impregnating dilute sulfuric acid as an electrolytic solution. did. In this example, a cast grid was used for the current collector,
Expanding grids may be used. The electric capacity was calculated by calculating the number of moles of lead atoms contained in the filled paste, and using the theoretical capacity when it is assumed that all of them carry out a two-electron reaction.

Comparative Examples 1 to 4 A battery manufactured under the same conditions as those of the above-described electrode plates except that the fibrous porous glass was not included was added in Comparative Example 1, the fibrous porous glass was not included and the paste was prepared. A battery in which the amount of water is increased and the packing density of the active material is lowered is set as Comparative Example 2. Further, a battery produced by adding powdery porous glass or glass cotton in place of the fibrous porous glass and using the same method was set as Comparative Example 3 or Comparative Example 4.

Table 1 shows the discharge capacities obtained by discharging the battery of the present invention and the batteries of Comparative Examples 1, 2, 3, and 4 at a constant current of 0.1C to 3.0C. In addition, 1C discharge of each battery (final voltage 1.3
V) shows the charging / discharging life performance at 1 C charge (150% charge of discharge capacity). The cycle life was the number of cycles until the initial discharge capacity was reduced to 50%. As is clear from Table 1, the batteries using the electrode plate according to the present invention have significantly higher high rate discharge characteristics than Comparative Example 1 as in Comparative Examples 2, 3 and 4. On the other hand, regarding the cycle characteristics of Table 2, the battery using the electrode plate according to the present invention has a larger cycle life number than Comparative Examples 2 and 3 as in Comparative Examples 1 and 4. From these facts, it was demonstrated that by applying the present invention, a battery having excellent high rate discharge characteristics and long life can be constructed.

[0017]

[Table 1]

[0018]

[Table 2]

The reason why the above results are obtained can be explained as follows. In the electrode plate according to the present invention shown in FIG. 1, the electrolytic solution is held in the fibrous porous glass 1, and the glass fibers form a network as a diffusion passage of sulfuric acid from the bulk of the electrolytic solution to the inside of the electrode plate. There is. Further, the fibrous porous glass 1 is entangled with the active material particles 4 and also plays a role as a binder for preventing the active material from falling off, thereby effectively suppressing a decrease in cycle life. Reference numeral 5 represents a current collector grid. Therefore, more electrolyte solution is contained in the interparticle pores 6 of the electrode plate than in the electrode plate of Comparative Example 1 as shown in FIG. 3 in which the electrolyte solution is contained, and the reaction proceeds smoothly even at high rate discharge. . Further, in the low-density-filled electrode plate of Comparative Example 2 in FIG. 4, the active material is reduced, the volume occupied by the pores 6 and the voids 7 is increased accordingly, and the amount of electrolyte retained is the same as in Comparative Example 1. However, the strength of the porous structure decreases, the active material falls off, and the cycle life decreases.

In the powdery porous glass of Comparative Example 3, the porous glass contains sulfuric acid, the amount of sulfuric acid in the electrode plate is increased, and the high rate discharge characteristics are improved. However, since it is powdery, a network of sulfuric acid diffusion from the electrolyte layer to the inside of the electrode plate is not formed, and the high rate discharge characteristics are inferior to the electrode plate to which the fibrous porous glass is added. In the electrode plate to which the glass cotton of Comparative Example 4 is added, sulfuric acid is contained in the gaps in which some fibers are twisted together. Therefore, the content of the electrolytic solution per unit weight of the glass wool and the fibrous porous glass is obviously higher in the fibrous porous glass, and a large effect can be obtained with a smaller addition amount than that of the glass cotton. Although the effect of the positive electrode was described in this example, when a battery having a negative electrode capacity regulation was manufactured by the same method and the effect on the negative electrode was investigated, the same results as in the case of the positive electrode were obtained. It was confirmed that it was also effective against.

Example 2 The amount of fibrous porous glass added was examined in the same manner as in Example 1 except that the amount of fibrous porous glass added was changed to prepare a positive electrode plate and a negative electrode plate. The theoretical capacity of the electrode plate is 1 Ah and 0.8 Ah, respectively, and the addition amount of the fibrous porous glass is 7%, 5%, 3%, 1% by weight ratio with respect to the lead component in the mixture, respectively.
It was set to 0.3% and 0.1%. A constant current discharge of 1 C was carried out in a system containing a pure lead plate as a counter electrode to these electrode plates in a large excess of an electrolytic solution, and the discharge capacity was measured. Discharge is finished with the reference electrode Hg ₂
0.8 V for the positive electrode and -0.3 for the negative electrode with respect to SO ₄ / Hg
V was defined as the final voltage. The results of discharging the positive electrode are shown in FIG.
For comparison, the discharge performance of an electrode plate containing no fibrous porous glass is also shown.

As shown in FIG. 5, the discharge capacity is improved by adding 0.1% or more of the fibrous porous glass, but the effect is weakened when the addition amount exceeds 5%, and 7%. Shows no superiority to the comparative example. When the same experiment was performed for the negative electrode, the same result as that for the positive electrode was obtained. From these results, the addition amount of the fibrous porous glass is preferably 5% to 0.1% by weight ratio with respect to the lead component in the active material mixture.

Example 3 To an active material mixture mainly composed of lead powder, 2% of fibrous porous glass was added with respect to the weight of the lead component in the mixture, and this was added to polyfluoride as a binder. Using a paste prepared by kneading vinylidene with a solution prepared by dissolving vinylidene in N-methylpyrrolidone as a solvent, a battery was experimentally manufactured in the same manner as in the above-mentioned example. The discharge capacity at a high rate discharge of 1 C or more of this battery is increased by 10 to 15% as compared with the battery in which the fibrous porous glass is not added, and the cycle life is 27
0 cycles were obtained. From this, the present invention is also applied to the case where the electrode plate is formed by using the organic polymer resin as the binder and kneading the active material mixture with the solution obtained by dissolving the organic polymer resin in the solvent. Has been confirmed to be effective.

[0024]

As described above, according to the present invention, the electrolytic solution can be retained in the electrode plate by adding the fibrous porous glass to the active material mixture, and at the same time, the diffusion path of sulfuric acid can be formed. Since this can be ensured, it is possible to obtain a lead storage battery having excellent high rate discharge characteristics and cycle life by using this electrode plate.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a single fiber of a fibrous porous glass used in an example of the present invention.

FIG. 2 is a schematic view showing a cross section of a main part of a lead acid battery electrode plate according to the present invention.

FIG. 3 is a schematic view showing a cross section of a main part of a conventional high-density packed electrode plate.

FIG. 4 is a schematic view showing a cross section of a conventional low-density packed electrode plate.

FIG. 5 is a diagram showing the relationship between the amount of fibrous porous glass added and the positive electrode discharge characteristics.

[Explanation of symbols]

1 Fibrous porous glass 2 core material 3 Porous layer 4 Active material particles 5 Current collector grid 6 Voids between particles 7 Void

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-56-50059 (JP, A) JP-A-5-198299 (JP, A) JP-A-4-87153 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) H01M 4/62 H01M 4/14 H01M 4/20 H01M 4/68

Claims (3)

(57) [Claims] 1. A glass core material and the surface of the glass core material processed in an active material mainly composed of lead or lead dioxide.
An electrode plate for a lead storage battery, which comprises a fibrous porous glass having a porous layer formed therein . 2. A glass core in an active material mainly composed of lead powder.
Material and a porous layer processed on the surface of the glass core material
A fibrous porous glass having is mixed, and a paste made by kneading this with water and sulfuric acid is filled in a lead alloy current collector,
A method of manufacturing an electrode plate for a lead storage battery, which is an electrode plate after an aging step and a chemical conversion step. 3. A glass core in an active material mainly composed of lead powder.
Material and a porous layer processed on the surface of the glass core material
With a mixture of porous Shitsuga la scan fibrous, which the organic polymeric resin as a binder were Nurigi the kneaded paste with a solution dissolved in a solvent on a current collector made of lead alloy A method for manufacturing an electrode plate for a lead storage battery, which is a plate after being subjected to a drying, chemical conversion process.