JP6638244B2 - Control valve type lead-acid battery - Google Patents

Description

  The present invention relates to a control valve type lead storage battery in which an electrode plate group in which a positive electrode plate and a negative electrode plate are alternately stacked via a separator and an electrolytic solution are accommodated in a battery case.

  Control valve type lead-acid batteries are relatively inexpensive, have high reliability and are maintenance-free, and are widely used in various fields such as uninterruptible power supply devices and power storage applications.

The electrolyte of the control valve type lead-acid battery is usually retained in a separator. When the lead storage battery is in an overdischarged state, the specific gravity of the electrolytic solution tends to decrease and the pH tends to increase. If this state continues for a long time, lead sulfate generated in the negative electrode plate by the discharge dissolves in the electrolytic solution. When charging from this state, a dendrite-like lead crystal may grow on the negative electrode plate side. Further, when the specific gravity of the electrolytic solution increases due to charging, lead sulfate precipitates in the separator. As the charging proceeds further, on the negative electrode side, the dendritic lead crystals are reduced to metallic lead (Pb), and the lead sulfate crystals precipitated in the separator are oxidized to lead dioxide (PbO ₂ ), and the crystals grow to form the separator. A penetrating short circuit that penetrates and connects the positive electrode plate and the negative electrode plate occurs. In order to prevent this osmotic short circuit, for example, a method of adding boric acid to a separator (Patent Document 1) and a method of adding zeolite (Patent Document 2) are disclosed.

Japanese Patent No. 4250910 JP 2006-59613 A

  However, the separators described in Patent Documents 1 and 2 require a large amount of inorganic substances such as boric acid, mesoporous silica, and zeolite to be contained in the separator in order to prevent osmotic short circuit. When a large amount of an inorganic substance is contained in the separator, there is a problem that the entire separator becomes hard and handling properties are deteriorated.

  Further, it is conceivable that the addition of a large amount of an inorganic substance closes the opening of the separator, lowers the diffusivity of the electrolyte, and deteriorates the discharge characteristics.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a control valve type lead-acid battery that can prevent a permeation short circuit.

  A control valve type lead storage battery to be improved by the present invention contains an electrode group in which a positive electrode plate and a negative electrode plate are alternately stacked via a separator, and an electrolytic solution in a battery case.

  In the present invention, at least one of the particles of the amorphous clay mineral and the particles of the quasicrystalline clay mineral are scattered between the positive electrode plate and the negative electrode plate. And, the electrolyte solution contains magnesium ions.

  When the control valve type lead storage battery of the present invention is in an overdischarged state, that is, when the electrolyte approaches neutrality (or in a neutral region), the amorphous clay mineral or quasicrystalline clay mineral adsorbs lead ions and charges the battery. When the state, that is, when the electrolytic solution approaches acidic (or in the acidic region), lead ions are released (or desorbed). Therefore, the lead ion concentration in the electrolytic solution in the discharged state is reduced, and it is possible to prevent lead sulfate from depositing in the separator.

In particular, in the present invention, since the electrolyte solution contains magnesium ions, it is possible to suppress the dissolution of lead sulfate generated by discharging the lead storage battery in the electrolyte solution. Specifically, when magnesium sulfate is added as a magnesium ion to the sulfuric acid electrolytic solution, ionization easily proceeds according to the following equation (2). When the active material reacts with the electrolytic solution during discharging to lower the concentration of sulfate ions in the electrolytic solution, the following formula (1) is established due to the existence of SO4 ^{2- according} to the following formula (2), and lead sulfate is obtained. Can be suppressed from being dissolved in the electrolytic solution.

すなわち、正極板と負極板との間に散在する粘土鉱物は、近傍のＰｂイオンを吸着し、散在する粘土鉱物から離れたＰｂイオンに対しては、硫酸電解液中のマグネシウムイオンが作用して、負極板側でデンドライト状の鉛結晶が成長するのを抑制することができる。したがって、本発明によれば、セパレータの取り扱い性や電解液の拡散性を低下させることなく、セパレータ中に析出した硫酸鉛塩結晶が酸化して二酸化鉛に酸化して、結晶が成長してセパレータを貫通するのを防止することができる。

That is, the clay mineral scattered between the positive electrode plate and the negative electrode plate adsorbs nearby Pb ions, and magnesium ions in the sulfuric acid electrolyte act on the Pb ions separated from the scattered clay minerals. In addition, it is possible to suppress the growth of dendritic lead crystals on the negative electrode plate side. Therefore, according to the present invention, without decreasing the handleability of the separator and the diffusibility of the electrolytic solution, the lead sulfate crystals precipitated in the separator are oxidized and oxidized to lead dioxide, and the crystals grow to form a separator. Can be prevented from penetrating.

Preferably, the content of magnesium ions with respect to the electrolyte is 0.05 to 2.5 mol / dm ³ . When the content of magnesium ion is less than 0.05 mol / dm ³ , or when the content of magnesium ion exceeds 2.5 mol / dm ³ , the precipitation of lead sulfate in the separator is permanently prevented. Effect is difficult to obtain.

  The place where the particles of the amorphous clay mineral or the quasicrystalline clay mineral are scattered may be anywhere between the positive electrode plate and the negative electrode plate. For example, they may be scattered in the electrolytic solution or may be scattered fixed to the separator. Further, it may be scattered on the surface of the positive electrode active material of the positive electrode plate, or may be scattered on the surface of the negative electrode active material of the negative electrode plate. Further, clay mineral particles may be scattered in at least two of these places. In the vicinity of the place where the clay minerals are scattered, the clay mineral particles adsorb Pb ions, and in the place away from the clay mineral particles, the magnesium ions in the sulfuric acid electrolyte act as described above to generate Pb ions. Suppress generation. That is, due to the synergistic effect of these, it becomes possible to suppress the growth of dendritic lead crystals on the negative electrode plate side.

  In particular, when these clay mineral particles are fixed to a separator, a glass fiber mat holding at least one of amorphous clay mineral particles and quasicrystalline clay mineral particles can be used as a separator. Since such a glass fiber mat easily holds the particles of the amorphous clay mineral and the particles of the quasicrystalline clay mineral, it is necessary to maintain the functions of the particles of the amorphous clay mineral and the particles of the quasicrystalline clay mineral. Can be.

  These clay minerals that exist between the positive electrode plate and the negative electrode plate can adsorb and release lead ions within the range where the pH of the dilute sulfuric acid electrolyte changes when the control valve type lead-acid battery is charged and discharged. It is preferable that the adsorption rate of lead ions changes. Further, those having a large specific surface area are preferable because the amount of adsorption and release are large, and it is more preferable that they are easily available and inexpensive. Further, it is preferable to use a material such as iron or copper which has a low hydrogenation voltage and does not contain a metal which accelerates the self-discharge reaction of a lead storage battery. Imogolite particles are preferred as such amorphous clay mineral particles, and allophane particles are preferred as quasicrystalline clay mineral particles.

  As for amorphous clay minerals such as imogolite and quasicrystalline clay minerals such as allophane, the surface charge depends on the pH of the solution, and the pH at which the surface charge is changed differs for each mineral. Specifically, amorphous or quasi-crystalline clay minerals such as imogolite and allophane are negatively charged when approaching neutral or alkaline (or in the neutral or alkaline region) and adsorb metal ions, It is known that when approaching acidity (or in the acidic region), it becomes positively charged and releases metal ions. When the controlled-valve lead-acid battery of the present invention is in an overdischarged state, that is, when the electrolyte approaches neutral (or in a neutral region), clay minerals such as imogolite and allophane adsorb lead ions, and a charged state, that is, the electrolyte Releases lead ions as they approach acidity (or in the acidic region). Therefore, the lead ion concentration in the electrolytic solution in the discharged state is reduced, and the precipitation of lead sulfate in the separator can be permanently prevented.

  In addition, the particles of these clay minerals are allophane particles having a hollow spherical shape with a diameter of 3.0 to 5.5 nm, and imogolite particles having a tube shape with an inner diameter of 0.5 to 1.20 nm and an outer diameter of 1.0 to 3.0 nm. It has a small particle size and a high specific surface area among clay minerals. Optimally, when imogolite having a small particle size and a high specific surface area is used, the amount of adsorption and release can be maximized in a range where the pH of the dilute sulfuric acid electrolyte of the lead storage battery changes. Further, although the specific surface area is slightly lower than that of the above clay minerals, it is also possible to use clay minerals such as kaolin minerals and aluminum hydroxide.

Abundance of imogolite particles is preferably in the range of less electrolyte volume per 0.064kg / m ³ or more 19.8 kg / m ^3. When the amount of the imogolite particles is less than 0.064 kg / m ³ per electrolyte volume, the function of adsorbing or desorbing Pb ions is not sufficiently exhibited, and when the amount exceeds 19.8 kg / m ³ , It may affect the diffusivity of the liquid.

Abundance of allophane particles is preferably in the range of less electrolyte volume per 0.082 kg / m ³ or more 27.6 kg / m ^3. Abundance of allophane particles, if less than the electrolyte volume per 0.082 kg / m ^3, when the adsorption or desorption function of Pb ions can not be sufficiently exhibited, and in excess of 27.6 kg / m ³ electrolytic It may affect the diffusivity of the liquid.

  ADVANTAGE OF THE INVENTION According to this invention, the short circuit at the time of overdischarge is permanently prevented, and the lead storage battery which prevents the penetration short circuit between positive / negative electrode plates can be provided.

It is a graph which shows the lead ion elution amount with respect to electrolyte solution (dilute sulfuric acid) specific gravity. It is a graph which shows the adsorption amount of lead ion with respect to pH of the particle of imogolite used in one embodiment of the control valve type lead storage battery of the present invention. It is a graph which shows the lead ion adsorption amount with respect to the pH of the allophane particle used in other embodiment of the control valve type lead storage battery of this invention. 2 is a graph showing the scattered amount of imogolite particles in the embodiment of FIG. 1. FIG. 5 is a graph in which allophane particles in the embodiment of FIG. 3 are measured in the same manner as FIG.

  Hereinafter, an embodiment of a control valve type lead storage battery of the present invention will be described.

<Required amount of imogolite and allophane>
The control valve type lead storage battery of the present invention is such that when clay minerals such as imogolite are scattered between the positive electrode plate and the negative electrode plate, the clay mineral preferentially adsorbs lead ions from the electrolyte in the neutral region, and in the acidic region. Since lead ions are released (or desorbed) into the electrolytic solution, precipitation of lead sulfate crystals in the separator can be suppressed.

  Imogolite, which is a clay mineral in the present embodiment, uses a slurry in which glass fiber, imogolite and water are mixed when forming a glass fiber mat separator, so that imogolite particles are bonded to glass fiber and intermolecular force. Scattered inside and on the surface of the separator. In another embodiment, imogolite is scattered as a two-layer structure including a separator formed by the above method and having imogolite adhered thereto, and a separator having a role of holding an electrolyte containing glass fiber as a main component. At this time, it is preferable to arrange the separator to which the particles of imogolite are attached so as to be in contact with the electrode plate surface. In still another embodiment, imogolite particles are dispersed between a positive electrode and a negative electrode by pouring the imogolite particles into a battery case in a state where the particles are dissolved in dilute sulfuric acid as an electrolytic solution. In still another embodiment, imogolite particles are dispersed in the gel electrolyte using a gel electrolyte prepared by adding an inorganic colloid material such as snowtex to the electrolyte.

The required scattered amount of imogolite as the clay mineral in the present embodiment is preferably at least 0.064 kg / m ^{3 with} respect to the volume of the electrolyte. This is based on the following calculation results. By dispersing imogolite in the separator in an amount of 0.064 kg / m ³ or more, it becomes possible to adsorb all Pb ions dissolved in the electrolytic solution, suppress precipitation of lead sulfate crystals, and prevent short circuits.

The highest PbSO ₄ solubility when the PbSO ₄ solubility specific gravity of the dilute sulfuric acid showing a 1.00,
2.30 mmol / m ³ ... (1) (calculated from FIG. 1 below)
In FIG. 1, the amount of lead ion eluted when 1 mg / L of lead sulfate (manufactured by Strem Chemicals, Inc.) was dissolved at a specific gravity of each electrolytic solution was measured using an Optima 4300DV: ICP apparatus (manufactured by PerkinElmer).

The amount of Pb ion adsorbed by imogolite is
0.036 mol / kg (2) (calculated from FIG. 2 below)
In FIG. 2, 10 g of imogolite and 0.5 × 10 ⁻³ mol of lead sulfate (manufactured by Strem Chemicals, Inc.) are added to 1 L of a diluted sulfuric acid solution prepared to have a pH of about 2, and sodium hydroxide is added stepwise. The amount of lead ions adsorbed to the sample was measured using an Optima 4300DV: ICP device (manufactured by PerkinElmer).

The amount of imogolite required to adsorb all Pb ions dissolved in dilute sulfuric acid having a specific gravity of 1.00 is (1) / (2) = 0.064 kg / m ³ .

In another embodiment, when allophane is selected, the Pb ion adsorption amount of allophane is
0.028 mol / kg (3) (calculated from FIG. 3)
In FIG. 3, 10 g of allophane and 0.5 mmol of lead sulfate (manufactured by Strem Chemicals, Inc.) were added to 1 L of a diluted sulfuric acid solution prepared to have a pH of about 2, and sodium hydroxide was added stepwise. The lead ion adsorption amount was measured using an Optima 4300DV: ICP device (manufactured by PerkinElmer). Allophane P1 (200 mesh powder) (manufactured by Shinagawa Kasei Co., Ltd.) was used.

The amount of allophane that adsorbs all Pb ions dissolved in dilute sulfuric acid having a specific gravity of 1.00 is (1) / (3) = 0.082 kg / m ³ .

The scattered amount of imogolite and allophane in each embodiment is preferably 0.1 mol / L or less per liter of electrolyte solution (liter: hereinafter, "L" is used as a unit representing liter in the present specification). That is, imogolite scattered amount 19.8 kg / m ³ or less per electrolyte volume, it is preferable allophane scattered amount is less electrolyte volume per 27.6 kg / m ^3. This is because, when 0.05 mol / L is added, the discharge capacity is reduced by 5% or more in the rated capacity for 10 hours from the fully charged state as compared with the non-added state. With respect to the discharge reduction, it was specified that the discharge capacity was 95% or more of the rated capacity at the first test based on JISC8704-1: 2006 (FIGS. 4 and 5). Here, the molecular weight of imogolite was 198 g based on the chemical composition: (OH) ₃ Al ₂ O ₃ SiOH. Allophane, chemical composition: was the molecular weight 276g based on _{2SiO 2 · Al 2 O 3 ·} 3H 2 O.

  In FIG. 4, the rated capacity at a 10-hour rate from the fully charged state when each amount of imogolite was added was measured and compared with the non-added state. In FIG. 5, allophane P1 (200 mesh powder) (manufactured by Shinagawa Kasei Co., Ltd.) was used as the allophane.

<Control valve type lead storage battery>
The control valve type lead-acid battery of the present embodiment can be manufactured as follows.

  First, barium sulfate is contained in an amount of 0.01 to 1.0% by mass, a carbon material is included in an amount of 0.2 to 1.4% by mass, and reinforcing short fibers and the like are contained in a lead powder containing lead monoxide as a main component. Water and lignin sulfonic acid are added to and mixed with the mixture added in an amount of from 0.05 to 0.3% by mass, and further diluted sulfuric acid is added and kneaded to prepare a negative electrode active material paste.

  The addition amount of lignin sulfonic acid is preferably 0.01 to 2.0% by mass as a resin solid content based on lead powder. Acrylic fibers, polypropylene fibers, polyethylene terephthalate fibers, and the like can be added as reinforcing short fibers. Examples of the carbon material include carbon black and graphite, and the carbon black can be selected from furnace black, channel black, acetylene black, thermal black, Ketjen black, and the like.

  Next, the negative electrode active material paste prepared as described above is filled in a current collector grid, then aged and dried to prepare an unformed negative electrode plate.

  The current collector grid is made of a lead-calcium-tin alloy, a lead-calcium alloy, or a lead-calcium-tin alloy or a lead-calcium alloy obtained by adding a small amount of arsenic, selenium, silver, or bismuth thereto. Can be used.

  The aging conditions are preferably set in an atmosphere at a temperature of 35 to 85 ° C. and a humidity of 50 to 90 RH% for 40 to 60 hours. The drying conditions are preferably set to a temperature of 50 to 80 ° C. for 15 to 30 hours.

  The positive electrode plate is prepared by adding short reinforcing fibers to lead powder mainly composed of lead monoxide, further adding water and diluted sulfuric acid, and kneading the mixture to form a positive electrode active material paste. After filling in the electric grid, aging and drying conditions are carried out under the same conditions as for the negative electrode plate to produce an unformed positive electrode plate.

  The produced negative electrode plate and positive electrode plate are alternately laminated with the lead battery separator of the present invention interposed therebetween, and the electrode plates having the same polarity are connected to each other by a strap to form an electrode plate group. The electrode group is arranged in a battery case to produce an unformed lead-acid battery.

  Dilute sulfuric acid was injected into the unformed battery as an electrolytic solution, and after the formation, the electrolytic solution was once removed, and then dilute sulfuric acid having a specific gravity of 1.25 to 1.35 was injected to obtain a lead storage battery of the present invention.

  The chemical conversion conditions and the specific gravity of the sulfuric acid used are preferably adjusted depending on the amount of the active material.

<Magnesium ion>
The electrolytic solution used in the present embodiment is obtained by diluting sulfuric acid with purified water, adjusting the specific gravity to 1.25 to 1.35, and adding and dissolving magnesium sulfate powder as an additive. In the separator mixed with imogolite, the addition amount (content) of magnesium sulfate (magnesium ion) is preferably 0.05 to 2.5 mol / dm ³ . Further, in the separator mixed with allophane, the addition amount (content) of magnesium sulfate (magnesium ion) is preferably 0.1 to 2.5 mol / dm ³ . Incidentally, 2.5 mol / dm ³ (20 ° C.) is the saturation amount of magnesium sulfate.

  As the addition amount (content) of magnesium sulfate (magnesium ion) increases, lead sulfate generated on the electrode plate when the storage battery is discharged is suppressed from dissolving in the electrolyte, and dendrite growth of lead sulfate crystals. Can be prevented.

  As an example of the present invention, a detailed description when imogolite is selected as the amorphous clay mineral will be described below.

  A method for producing imogolite used in this example will be described. 500 mL of an aluminum chloride aqueous solution having a concentration of 700 mmol / L was added with 500 mL of an aqueous sodium orthosilicate solution having a concentration of 350 mmol / L, followed by stirring for 30 minutes. To this solution, 330 mL of a 1 mol / L aqueous solution of sodium hydroxide was added to adjust the pH to 6.1. After the pH-adjusted solution was stirred for 30 minutes, centrifugation was performed for 5 minutes at a rotation speed of 3,000 rpm using a Suprema 23 and a standard rotor NA-16 manufactured by TOMY as a centrifugal separator. After centrifugation, the supernatant was drained, and the gel precipitate was redispersed in pure water to return to the volume before centrifugation. Such desalting treatment by centrifugation was performed three times. The gel precipitate obtained after discharging the supernatant liquid after the third desalting treatment was dispersed in pure water so as to have a concentration of 60 g / L, and manufactured by HORIBA: F-55 and an electric conductivity cell: 9382-10D. Was used to measure the electrical conductivity at room temperature (25 ° C.), and it was 1.3 S / m. To the gel precipitate obtained after the third supernatant was discharged after the desalting treatment, 135 mL of hydrochloric acid having a concentration of 1 mol / L was added to adjust the pH to 3.5, and the mixture was stirred for 30 minutes. The concentration of silicon atoms and the concentration of aluminum atoms in the solution at this time were measured by an ordinary method using an ICP emission spectrometer: P-4010 (manufactured by Hitachi, Ltd.), and the silicon atom concentration was 213 mmol / L. The aluminum atom concentration was 426 mmol / L. Next, the solution was placed in a dryer and heated at 98 ° C. for 48 hours (2 days). After heating, 188 mL of a 1 mol / L aqueous sodium hydroxide solution was added to the solution (aluminum silicate concentration: 47 g / L) to adjust the pH to 9.1. The aluminum silicate in the solution was aggregated by adjusting the pH, and the aggregate was precipitated by centrifugation as described above, and the supernatant was discharged. Desalting treatment was performed three times, in which pure water was added and the volume was returned to the volume before centrifugation. The gel precipitate obtained after discharging the supernatant liquid after the third desalting treatment was dispersed in pure water so as to have a concentration of 60 g / L, and manufactured by HORIBA: F-55 and an electric conductivity cell: 9382-10D. Was used to measure the electrical conductivity at room temperature (25 ° C.) and found to be 0.6 S / m. The gel precipitate obtained after discharging the supernatant liquid after the third desalting treatment was dried at 60 ° C. for 16 hours to obtain 30 g of imogolite.

  When allophane, a quasi-crystalline clay mineral, was selected as another example, P1 (200 mesh powder) (manufactured by Shinagawa Kasei Co., Ltd.) was used.

The content of each raw material component in the slurry was 78.9% by mass of glass fiber having an average fiber diameter of 1.0 μm, 10% by mass of imogolite, 10% by mass of a polypropylene emulsion resin as a binder, and 1.0% of Laccol as a surfactant. A slurry was prepared so as to be 0.1% by mass, and 0.1% by mass of diallyldimethylammonium chloride as a coagulant, and papermaking was performed. The thickness was 1.6 mm, the average pore diameter was 2.0 μm, the ignition loss was 10%, and the imogolite adhesion amount was 8 A separator of 0.6 × 10 ⁻⁵ kg was produced. The attached amount of imogolite can be adjusted by adjusting the amount of imogolite added to the slurry. The loss on ignition was measured by the following method. The sample is dried at 105 ± 5 ° C. for about 30 minutes, placed in a desiccator and allowed to cool, and then the weight (W1) is measured. Next, the sample was put in a crucible, put in a heating furnace at 500 ° C., and after 2 hours, a whitened sample was taken out, put in a desiccator, and allowed to cool. The weight (W2) was measured, and the ignition loss was calculated by the following formula. .

Burning weight loss (% by weight) = (W1-W2) / W1 × 100
The average pore diameter was measured by a mercury porosimeter (AutoPore IV 9500 V1.07 manufactured by Shimadzu). The amount of attached imogolite was measured using an energy dispersive X-ray spectrometer (S-3500N manufactured by HITACHI) and an EPMA (Electron Probe Micro Analyzer): EMIA-920V measured by HORIBA manufactured by HORIBA.

The content of each raw material component in the slurry was 78.9% by mass of glass fibers having an average fiber diameter of 1.0 μm, 10% by mass of allophane, 10% by mass of a polypropylene emulsion resin as a binder, and 1.0% of Laccol 1.0 as a surfactant. A slurry was prepared so as to be 0.1% by mass, and 0.1% by mass of diallyldimethylammonium chloride as a coagulant, and papermaking was performed. The thickness was 1.6 mm, the average pore diameter was 2.0 μm, the ignition loss was 10%, and the allophane adhesion amount was 8 A separator of 0.6 × 10 ⁻⁵ kg was produced. The amount of allophane attached can be adjusted by adjusting the amount of allophane added to the slurry. The ignition loss, average pore diameter, and allophane adhesion amount were measured using the same measurement methods as in the case of imogolite.

Also, imogolite can be dispersed between the positive electrode plate and the negative electrode plate by the following method. The content of each raw material component in the slurry was 88.9% by mass of glass fibers having an average fiber diameter of 1.0 μm, 10% by mass of a polypropylene emulsion resin as a binder, 1.0% by mass of Laccol as a surfactant, and a flocculant. A slurry was prepared so as to have a diallyldimethylammonium chloride content of 0.1% by mass, papermaking was performed, and a glass fiber having a thickness of 1.4 mm and an average pore diameter of 2.0 μm was mainly constituted to hold an electrolyte. Was obtained. The content of each raw material component in the slurry was 78.9% by mass of glass fiber having an average fiber diameter of 1.0 μm, 10% by mass of imogolite, 10% by mass of a polypropylene emulsion resin as a binder, and Laccol 1 as a surfactant. A slurry was prepared so as to have a mass of 0.0% by mass and 0.1% by mass of diallyldimethylammonium chloride as a coagulant, and papermaking was performed. A separator having 8.6 × 10 ⁻⁵ kg attached was prepared. These two types of separators were stacked so that the center part was a separator for holding the electrolyte and the both sides were a separator to which imogolite was attached, thereby producing a 1.8 mm thick separator. Then, the electrode plate group was press-fitted into an acrylic battery case so that the separator density became 250 kg / m ³ .

Further, another method for dispersing imogolite between the positive electrode plate and the negative electrode plate will be described below. The content of each raw material component in the slurry was 88.9% by mass of glass fiber having a fiber diameter of 1.0 μm, 10% by mass of a polypropylene emulsion resin as a binder, 1.0% by mass of Laccol as a surfactant, and a coagulant. A slurry was prepared so as to have a certain diallyldimethylammonium chloride content of 0.1% by mass, papermaking was performed, and a separator having a thickness of 1.8 mm and an average pore diameter of 2.0 μm was obtained. The electrolyte used was a sulfuric acid solution having a specific gravity of 1.30, to which imogolite was added as an additive at 0.06 kg / m ³ per electrolyte solution volume. The electrode group was assembled under pressure into an acrylic battery case so that the separator density became 250 kg / m ³ .

  As another example, even if a gel electrolyte prepared by adding an inorganic colloid material such as snowtex to the electrolyte is used, adsorption and release of Pb ions are possible, and the same effect can be obtained.

As an electrolyte, 0.05, 0.1, 0.5, 1.0, and 2.5 mol / dm ^{3 of} magnesium sulfate was dissolved as an additive in a sulfuric acid solution having a specific gravity of 1.30.

<Manufacture of electrode plates>
Lead powder containing lead monoxide as a main component: 100 kg, PET fiber (fineness: 2.0 D (denier), fiber length: 3.0 mm): 0.2 kg, and after adding water, dilute sulfuric acid: 20 kg ( To the mixture was added 30 kg of lead and 30 parts of agitated slurry, followed by kneading to prepare a paste-like active material for a positive electrode. The prepared positive electrode paste active material was filled in a lead-calcium-tin alloy current collector having a width of 55 mm, a length of 117 mm, and a thickness of 4 mm. Then, after aging in the air at 40 ° C. and a humidity of 95% for 24 hours, the paste was dried at 50 ° C. for 16 hours to produce an unformed paste-type positive electrode plate.

  Lead powder containing lead monoxide as a main component: 90 kg, PET fiber (fineness: 2.0 D (denier), fiber length: 3.0 mm): 0.27 kg, barium sulfate: 0.45 kg, lignin: 0.18 kg After mixing and adding water, 10 kg of dilute sulfuric acid (specific gravity: 1.260, converted at 20 ° C.) was added and kneaded to prepare a paste-like active material for a negative electrode. The amount of water to be added was adjusted so that the paste-like active material had a predetermined hardness in consideration of the filling property of the paste-like active material into the current-collecting grid.

  The prepared paste active material for negative electrode was filled into a lead-calcium-tin alloy current collector having a width of 60 mm, a length of 120 mm, and a thickness of 2.0 mm to prepare an unformed paste-type negative electrode plate. did. Then, after aging in the air at 40 ° C. and a humidity of 95% for 24 hours, the paste was dried at 50 ° C. for 16 hours to prepare an unformed paste negative electrode plate.

(Example 1)
The prepared three paste-type positive electrode plates and four paste-type negative electrode plates are alternately laminated via a separator made of a nonwoven fabric mainly composed of glass fiber having a thickness of 1.8 mm, and the ears of the electrodes are welded. The electrode group was assembled into an acrylic battery case under pressure so as to have a separator density of 250 kg / m ³ . The separator used in this example had a thickness of 1.8 mm, an average pore diameter of 2.0 μm, a loss on ignition of 10%, and an attached amount of imogolite of 8.6 × 10 ⁻⁵ kg. In the above-mentioned battery case, a solution obtained by adding 0.05 mol / dm ^{3 of} magnesium sulfate as an additive to a sulfuric acid solution having a specific gravity of 1.30 was used. 0.13 × 10 ⁻³ m ³ of dilute sulfuric acid electrolyte having a specific gravity of 1.30 was injected, and the battery was formed under the conditions of an ambient temperature of about 25 ° C., a charge amount of 250%, and a formation time of 48 hours. A control valve type lead-acid battery having a capacity of 17 Ah-2V was produced.

(Examples 2 to 5)
A control valve was used in the same manner as in Example 1 except that the addition amounts of magnesium sulfate in the electrolytic solution used in Example 1 were 0.1, 0.5, 1.0, and 2.5 mol / dm ³ , respectively. A lead storage battery was manufactured.

(Comparative Example 1)
The prepared three paste-type positive electrode plates and four paste-type negative electrode plates are alternately laminated via a separator made of a nonwoven fabric mainly composed of glass fiber having a thickness of 1.8 mm, and the ears of the electrodes are welded. The electrode group was assembled into an acrylic battery case under pressure so as to have a separator density of 250 kg / m ³ . The separator used in this comparative example had a thickness of 1.8 mm, an average pore diameter of 2.0 μm, and a loss on ignition of 10%. Example 1 was repeated except that imogolite was not mixed in the separator and magnesium sulfate was not added as an additive to the sulfuric acid electrolyte having a specific gravity of 1.30.

(Comparative Example 2)
The prepared three paste-type positive electrode plates and four paste-type negative electrode plates are alternately laminated via a separator made of a nonwoven fabric mainly composed of glass fiber having a thickness of 1.8 mm, and the ears of the electrodes are welded. The electrode group was assembled into an acrylic battery case under pressure so as to have a separator density of 250 kg / m ³ . The separator used in this comparative example had a thickness of 1.8 mm, an average pore diameter of 2.0 μm, a loss on ignition of 10%, and an adhesion amount of imogolite of 8.6 × 10 ⁻⁵ kg. Example 1 was the same as Example 1 except that magnesium sulfate was not added as an additive to a sulfuric acid electrolyte having a specific gravity of 1.30.

<Short circuit test of control valve type lead storage batteries of Examples and Comparative Examples>
After the above-mentioned battery case formation, the fully charged state of the control valve type lead-acid battery was discharged in the atmosphere at an ambient temperature of 25 ° C. at 0.2 CA (1.8 A) to a final voltage of 1.75 V / cell. Check the initial discharge capacity. Subsequently, a 30 Ω, 10 W enamel resistor is attached between the positive electrode terminal and the negative electrode terminal of the control valve type lead-acid battery, and left in the atmosphere at an ambient temperature of 40 ° C. for 2 weeks to completely discharge. Next, constant voltage charging at 2.45 V / cell and a limiting current of 1.7 A is performed for 16 hours in the atmosphere at an ambient temperature of 25 ° C. Then, the control valve type lead storage battery was disassembled in the charged state, and it was confirmed whether or not there was a short circuit mark on the separator. The above-described short-circuit test method is a so-called accelerated test method.

  The results of the short-circuit test were evaluated by judging the case of short-circuiting as “x” and the case of not short-circuiting as “「 ”.

<Repeated short circuit test>
The above-mentioned short circuit test was repeated, and the difficulty of short circuit was evaluated. The results of the repeated short-circuit evaluation were as follows: "x" indicates that the test was repeated less than 1 time, "x" indicates that the test was short-circuited once or more than 2 times, and "「 "indicates that the test was short-circuited 2 times or less than 4 times. ○ ”, those that did not short-circuit four or more times were evaluated as“ ◎ ”.

（実施例６）
作製したペースト式正極板３枚とペースト式負極板４枚を、厚みが１．８ｍｍのガラス繊維を主成分とする不織布からなるセパレータを介して交互に積層し、電極の耳部を溶接して極板群を作製した。この極板群を、アクリル製の電槽にセパレータ密度が２５０ｋｇ／ｍ³になるように加圧して組み込んだ。本実施例で使用するセパレータは、１．８ｍｍ厚、平均細孔径２．０μｍ、灼熱減量１０％、アロフェン付着量８．６×１０^-5ｋｇとしたものを使用した。上記電槽に、比重１．３０の硫酸溶液中に添加剤として硫酸マグネシウムを０．１モル／ｄｍ³加えたものを用いた。比重１．３０の希硫酸電解液を０．１３×１０^-3ｍ³注入し、周囲温度が約２５℃、課電量が２５０％、化成時間が４８時間の条件で電槽化成を行い、公称容量が１７Ａｈ−２Ｖの制御弁式鉛蓄電池を作製した。

(Example 6)
The prepared three paste-type positive electrode plates and four paste-type negative electrode plates are alternately laminated via a separator made of a nonwoven fabric mainly composed of glass fiber having a thickness of 1.8 mm, and the ears of the electrodes are welded. An electrode group was prepared. The electrode group was assembled under pressure so as to have a separator density of 250 kg / m ³ in an acrylic battery case. The separator used in this example had a thickness of 1.8 mm, an average pore diameter of 2.0 μm, a loss on ignition of 10%, and an attached amount of allophane of 8.6 × 10 ⁻⁵ kg. In the above-mentioned battery case, a solution obtained by adding 0.1 mol / dm ^{3 of} magnesium sulfate as an additive to a sulfuric acid solution having a specific gravity of 1.30 was used. 0.13 × 10 ⁻³ m ³ of dilute sulfuric acid electrolyte having a specific gravity of 1.30 was injected, and the battery was formed under the conditions of an ambient temperature of about 25 ° C., a charge amount of 250%, and a formation time of 48 hours. A control valve type lead-acid battery having a capacity of 17 Ah-2V was produced.

(Examples 7 to 9)
A control valve type lead-acid battery was fabricated in the same manner as in Example 6, except that the amounts of magnesium sulfate in the electrolyte used in Example 1 were changed to 0.5, 1.0, and 2.5 mol / dm ³ , respectively. did.

表１に示した試験結果から、実施例１〜５（イモゴライトが混抄されたセパレータ）は、希硫酸電解液中に添加剤として硫酸マグネシウムを０．０５〜２．５ｍｏｌ／ｄｍ³加えることで、繰り返し短絡試験に対する短絡の抑制効果が大きく、比較例１（イモゴライトが混抄されず、硫酸マグネシウムを添加しない場合）よりも著しく優れることが判った。また、繰り返し短絡試験に対する短絡の抑制効果の観点から、実施例１〜５は、比較例２（イモゴライトが混抄されず、硫酸マグネシウムを添加しない場合）よりも優れることが判った。

From the test results shown in Table 1, Examples 1 to 5 (separator mixed with imogolite) were obtained by adding 0.05 to 2.5 mol / dm ^{3 of} magnesium sulfate as an additive to a diluted sulfuric acid electrolyte solution. It was found that the effect of suppressing short-circuiting in the repeated short-circuit test was large, and was significantly superior to Comparative Example 1 (when imogolite was not mixed and magnesium sulfate was not added). In addition, from the viewpoint of the effect of suppressing short circuits in the repeated short circuit test, Examples 1 to 5 were found to be superior to Comparative Example 2 (when imogolite was not mixed and magnesium sulfate was not added).

Further, from the test results shown in Table 2, for the separator mixed with allophane (Examples 6 to 9), 0.1 to 2.5 mol / dm ^{3 of} magnesium sulfate was added as an additive to the diluted sulfuric acid electrolyte solution. Thus, it was found that the effect of suppressing the short-circuit in the repeated short-circuit test was large, and was significantly superior to Comparative Example 1 (in which imogolite was not mixed and magnesium sulfate was not added). In addition, from the viewpoint of the effect of suppressing short circuits in the repeated short circuit test, Examples 6 to 9 were found to be superior to Comparative Example 2 (when imogolite was not mixed and magnesium sulfate was not added).

  These results are considered to be due to the fact that the addition of magnesium sulfate as magnesium ions suppresses the dissolution of lead sulfate generated in the negative electrode plate by the discharge into the electrolytic solution. By these actions, it is possible to prevent a penetration short circuit between the positive and negative electrode plates. Therefore, according to the present invention, the sulfate crystals precipitated in the separator are oxidized to lead dioxide without deteriorating the handleability of the separator and the diffusivity of the electrolytic solution, and the crystals grow and penetrate the separator to cause osmotic short circuit. Can be prevented from occurring.

Examples 3 to 5 (when imogolite is mixed and the amount of magnesium sulfate added is 0.5 to 2.5 mol / dm ³ ) and Examples 8 and 9 (allophane is mixed and the amount of magnesium sulfate added) Is 1.0 to 2.5 mol / dm ³ ), the effect of suppressing the short circuit in the repeated short circuit test is very large, and the permanent short circuit preventing effect is remarkable.

Claims (2)

In a battery case, a positive-electrode plate and a negative-electrode plate, in a control valve-type lead-acid battery containing an electrode group and an electrolyte that are alternately stacked via a separator holding imogolite particles ,
The amount of the imogolite is 0.064 kg / m ³ or more and 19.8 kg / m ³ or less per electrolyte volume ;
The control valve type lead storage battery , wherein the electrolyte contains 0.5 to 2.5 mol / dm ³ of magnesium ions with respect to the electrolyte . In a battery case, a positive-electrode plate and a negative-electrode plate, in a control valve-type lead-acid battery containing an electrode group and an electrolyte that are alternately stacked via a separator that holds allophane particles,
  The amount of the allophane is 0.082 kg / m per electrolyte volume. ^Three 27.6 kg / m or more ^Three Below,
The electrolyte is 1.0 to 2.5 mol / dm with respect to the electrolyte. ^Three A control valve type lead-acid battery characterized by containing magnesium ions.

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