JP6642832B2 - Lead storage battery - Google Patents

Description

  The present invention relates to a lead storage battery.

In recent years, power generation facilities using natural energy such as sunlight and wind power have been actively installed in order to reduce CO ₂ . Attention has been paid to the use of storage battery equipment in order to equalize these fluctuations in generated power and power consumption. In particular, lead storage batteries have been actively used for these facilities from the viewpoint of safety and the like (see Patent Document 1).

JP 2006-049025 A

  Usually, in these power supply facilities, a plurality of batteries are used in series connection. Therefore, depending on the surrounding environment, the battery internal temperature may be 40 ° C. or higher. When used in such a high-temperature environment, the electrode material is likely to deteriorate, the capacity is likely to be reduced early, and the life may be shortened.

  The present invention solves the above-mentioned problems, and provides a long-life lead-acid battery even under high temperature use.

In view of the above prior art, the present inventors have conducted intensive studies and, as a result, have developed a novel lead-acid battery.
And they found that this new lead-acid battery has a long life. The present invention has been made based on this finding.

That is, the lead storage battery according to one aspect of the present invention includes:
A positive electrode plate,
A negative electrode plate,
And a lead-acid battery comprising:
The positive electrode plate includes a positive electrode material,
The negative electrode plate includes a negative electrode material,
The negative electrode material contains a synthetic shrinkproofing agent,
The total pore volume of the positive electrode material in a fully charged state is 0.08 to 0.16 mL / g,
Regarding the pore diameter of all the pores of the positive electrode material in a fully charged state, the ratio of pores of 1.2 μm or more is 35 vol% or less.

  According to one aspect of the present invention, a long-life lead-acid battery is provided.

5 is a graph showing the number of life cycles when the total pore volume (cumulative pore volume) of a positive electrode material is changed. 4 is a graph showing an initial capacity when the total pore volume of a positive electrode material is changed. 4 is a graph showing the number of life cycles when the proportion of pores having a diameter of 1.2 μm or more in all pores of a positive electrode material is changed. 4 is a graph showing the initial capacity when the ratio of pores having a diameter of less than 0.1 μm in all the pores of the positive electrode material is changed. It is a graph which shows the initial capacity at the time of changing the content of a synthetic preservative. It is a graph which shows the life cycle number at the time of changing the content of a synthetic shrinkproofing agent. It is a graph which shows the initial capacity at the time of changing the amount of the sulfur element (S element) of a synthetic shrinkproofing agent. It is a graph which shows the life cycle number at the time of changing the amount of the sulfur element (S element) of a synthetic shrinkproofing agent. 4 is a graph showing the number of life cycles when the density of a negative electrode material is changed.

  A preferred embodiment of the present invention will be described.

1. A lead storage battery according to one embodiment of the present invention is a lead storage battery including a positive electrode plate, a negative electrode plate, and an electrolyte. The positive electrode plate includes a positive electrode material, and the negative electrode plate includes a negative electrode material. The negative electrode material contains a synthetic shrinkproofing agent. The total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and the ratio of the pores of 1.2 μm or more in the total pore diameter of the positive electrode material is 35 vol%. It is as follows.
The electrode material includes not only the reactants but also all other additives. The electrode plate is composed of an electrode material and a current collector. Therefore, the electrode material means all of the electrode plate except for the current collector.

2. Positive electrode plate The type of the positive electrode plate is not particularly limited. As the positive electrode plate, for example, a clad type electrode plate and a paste type electrode plate can be used. As the clad type electrode plate, for example, an electrode plate is used in which a glass fiber is knitted into a tube shape and baked and then filled with a positive electrode material containing lead powder which is a positive electrode active material. The paste-type electrode plate is obtained, for example, by filling a current collector (grating body) such as an expanded, cast, or punched material with a paste of a positive electrode material containing a positive electrode active material, and then aging and drying. The paste of the positive electrode material can be obtained by kneading lead powder or the like with water and dilute sulfuric acid. Various additives may be added to the positive electrode material paste in addition to the positive electrode active material.

In the lead storage battery of one embodiment of the present invention, the total pore volume of the positively charged positive electrode material is 0.08 to 0.16 mL / g, and preferably 0.10 to 0.16 mL / g.
As for the pore diameter of all the pores of the positive electrode material in a fully charged state, the proportion of pores having a size of 1.2 μm or more is 35 vol% or less, preferably 30 vol% or less.
When the total pore volume of the positive electrode material and the proportion of the pores having a diameter of 1.2 μm or more in all the pores are within these ranges, the life is prolonged even at high temperatures.

Further, regarding the pore diameter in all the pores of the positive electrode material in a fully charged state, the ratio of pores smaller than 0.1 μm is not limited. Regarding the pore diameter in all the pores of the positive electrode material in a fully charged state, the proportion occupied by pores of less than 0.1 μm is preferably 40 vol% or less, more preferably 35 vol% or less.
Regarding the pore diameter in all the pores, when the proportion occupied by pores of less than 0.1 μm is within this range, the initial capacity tends to increase.

The total pore volume of the positive electrode material in a fully charged state, the proportion of pores having a diameter of 1.2 μm or more in all pores, and the proportion of pores having a diameter of less than 0.1 μm in all pores are: It is measured by the mercury intrusion method.
After the formation, the fully charged lead-acid battery is disassembled, the positive electrode plate is taken out, washed with water and dried to remove the electrolyte in the positive electrode plate. Next, the positive electrode material is separated from the positive electrode plate to obtain an uncrushed measurement sample. A sample is charged into a measuring container, evacuated and then filled with mercury, and the pressure is gradually increased to insert mercury into the pores. The pore distribution and total pore volume are determined from the pressure and the amount of mercury injected.

3. Negative electrode plate 3.1 Type of electrode plate The type of the negative electrode plate is not particularly limited. As the negative electrode plate, for example, a paste type electrode plate can be used. As the paste-type electrode plate, for example, an electrode plate in which a paste-like negative electrode material is applied to a current collector (lattice) such as a cast, expanded, or punched material manufactured using pure lead or a lead alloy is used. . The paste-type electrode plate is obtained, for example, by filling a current collector with a paste of a negative electrode material, followed by aging and drying. The paste of the negative electrode material can be obtained by kneading lead powder or the like with water and dilute sulfuric acid. Various additives may be added to the paste of the negative electrode material in addition to the negative electrode active material.

3.2 Density of Negative Electrode Material In the lead storage battery of one embodiment of the present embodiment, the density of the negative electrode material is not particularly limited. The density of the negative electrode material in a fully charged state is preferably 2.6 g / cm ³ or more and 4.0 g / cm ³ or less, and more preferably 2.9 g / cm ³ or more and 4.0 g / cm ³ or less.
When the density of the negative electrode material in the fully charged state is within this range, the charging efficiency tends to be improved and the cycle life performance tends to be improved.

Note that the density of the negative electrode material means the value of the bulk density of the negative electrode material in a fully charged state after formation, and is measured as follows. The battery after chemical formation is fully charged and then disassembled, and the obtained negative electrode plate is washed with water and dried to remove the electrolyte in the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an uncrushed measurement sample.
After charging the sample in the measuring container and evacuating, filling the mercury with a pressure of 0.5 to 0.55 psia, measuring the bulk volume of the negative electrode material, and dividing the mass of the measurement sample by the bulk volume, the negative electrode Find the bulk density of the material. The volume obtained by subtracting the mercury injection volume from the volume of the measurement container is defined as the bulk volume.

3.3 Synthetic Shrinkage Agent 3.3.1 Content of Synthetic Shrinkage Agent In the lead storage battery of the present embodiment, the content of the synthetic shrinkage preventive agent is not particularly limited. The content of the synthetic shrinkproofing agent is preferably 0.05% by mass or more and 0.3% by mass or less with respect to 100% by mass of the negative electrode material which has been formed and is fully charged. When the synthetic shrinkproofing agent is in this range, the effect of improving the life performance is high, and the initial capacity is also good.

3.3.2 Details of Synthetic Shrinking Agent The synthetic shrinking agent in the present embodiment is not particularly limited as long as it is an artificially synthesized shrinking agent. One kind of the synthetic shrinkproofing agent may be used alone, or two or more kinds may be used in combination.
For example, examples of the synthetic shrinkproofing agent include a reaction product of a compound having a plurality of phenolic hydroxyl groups with an aldehyde, and a reaction product of a naphthalene compound with an aldehyde. In addition, polyacrylic acid, a polymer of acrylamide / tertiarybutyl / sulfonic acid Na (ATBS polymer: ATBS is a registered trademark), sulfomethylated kraft lignin, N, N ′-(sulfonyldi-4,1-phenylene) bis ( A condensate using 1,2,3,4-tetrahydro-6methyl-2,4-dioxopyrimidine-5-sulfonamide) can also be used.
In the polymer of polyacrylamide / tertiary butyl / Na sulfonic acid, the ratio between the basic skeleton and the amount of the sulfonic acid group is not particularly limited, but the ratio between the basic skeleton and the amount of the sulfonic acid group is 1: 1 or more. Is preferred.

The compound having a plurality of phenolic hydroxyl groups is not particularly limited as long as it has a phenolic hydroxyl group. It may have two or more phenolic hydroxyl groups. These compounds may be used alone or in combination of two or more.
As the compound having a plurality of phenolic hydroxyl groups, bisphenols are preferably used. Bisphenols are compounds having two hydroxyphenyl groups. Examples of the bisphenols include bisphenol A, bisphenol S, bisphenol F, bisphenol AP, bisphenol AF, bisphenol B, bisphenol BP, bisphenol C, bisphenol E, bisphenol G, bisphenol M, bisphenol P, bisphenol PH, bisphenol TMC, and bisphenol Z. Etc. are exemplified. These may be used alone or in combination of two or more.

  The aldehyde is not particularly limited. Examples of the aldehydes include formaldehyde, paraformaldehyde, trioxane, tetraoxymethylene and the like. These may be used alone or in combination of two or more. Formaldehyde is preferably used because of its high reactivity with compounds having a plurality of phenolic hydroxyl groups.

Further, a sulfonic acid group (sulfo group) may be further introduced into a reaction product of a compound having a plurality of phenolic hydroxyl groups and an aldehyde. By introducing a sulfonic acid group, the amount of the sulfur element (S element) in the synthetic shrinkproofing agent can be increased.
The sulfonic acid group does not need to be directly bonded to the aromatic ring (for example, a phenyl group of bisphenols) of a compound having a plurality of phenolic hydroxyl groups. For example, an alkyl chain may be bonded to an aromatic ring, and a sulfonic acid group may be bonded to the alkyl chain.
In addition, whether the S element is contained as a sulfonic acid group or a sulfonyl group, the performance as a synthetic shrinkproofing agent is almost the same.

In the lead storage battery of one embodiment of the present embodiment, the amount of the sulfur element (S element) in the synthetic shrinkproofing agent is not particularly limited. The content of the sulfur element (S element) in the synthetic shrinkproofing agent is preferably 4000 μmol / g or more and 6500 μmol / g or less.
When the content of the sulfur element (S element) is in this range, the life tends to be longer under high temperature use, and the initial capacity tends to be higher. Although the reason is not clear, it is considered that the elution of the synthetic shrinkage agent from the negative electrode plate is small, and the colloidal particle size of the synthetic shrinkage agent is an optimal size for achieving both discharge performance and softening suppression effect. .

The molecular weight of the synthetic shrinkproofing agent is not particularly limited. The weight average molecular weight (Mw) of the synthetic shrinkproofing agent is preferably from 1,000 to 1,000,000, more preferably from 1,000 to 100,000, and further preferably from 1,000 to 20,000. This range is preferable from the viewpoint of synthesis of organic substances.
The measurement of the molecular weight is determined by gel permeation chromatography (GPC). The standard substance used for determining the molecular weight is sodium polystyrene sulfonate.
The molecular weight can be measured using the following apparatus and conditions.
GPC equipment: Build-up GPC system
SD-8022 / DP-820 / AS-8020 / CO-8020 / UV-8020 (Tosoh)
Column: TSKgel G4000SWXL, G2000SWXL (7.8 mmI.D. × 30cm) (Tosoh)
Detector: UV detector λ = 210nm
Eluent: 1mol / L NaCl: acetonitrile (7: 3)
Flow rate: 1ml / min.
Concentration: 10mg / mL
Injection volume: 10 μL
Standard substance: Na polystyrene sulfonate
(Mw = 275,000, 35,000, 12,500, 7,500, 5,200, 1,680)

Specific examples of the synthetic shrinkproofing agent include a condensate of bisphenol A having a sulfonic acid group introduced with formaldehyde, a condensate of bisphenol S having a sulfonic acid group introduced with formaldehyde, and a condensate of β-naphthalenesulfonic acid with formaldehyde ( Kao Corporation's trade name "Demol") can be suitably used. When bisphenol S is used, a sulfonic acid group and an S element derived from a sulfonyl group (—SO ₂ —) structure in bisphenol S are present in the synthetic shrinkproofing agent.

  Among the synthetic shrinkproofing agents, condensates of bisphenols are preferred. Bisphenol condensates are suitable for lead storage batteries that are used in a series connection of a plurality of batteries and are likely to be in a high-temperature environment because the performance of the condensates of the bisphenols is not impaired even when the high-temperature environment is experienced. The condensate of naphthalene sulfonic acid is less likely to have a smaller polarization than the condensate of bisphenols, and thus is suitable for a control valve type lead-acid battery in which liquid reduction characteristics are important.

Here, an example of a suitable method for synthesizing a condensate of bisphenols will be described. Bisphenols (bisphenols A, S, F, etc.), formaldehyde, and sulfite are mixed to obtain a formaldehyde condensate of bisphenols. At this time, the S amount of the shrinkproofing agent is adjusted by increasing or decreasing the amount of bisphenol S and the amount of sulfite according to the required amount.
However, it is preferable that the sulfite and the formaldehyde are reacted in substantially equimolar amounts. Since polymerization proceeds under alkaline conditions, it is preferable to use NaOH or the like as a pH adjuster and adjust the pH to about 12 (pH = 10 to 13).

  The reaction temperature is not particularly limited, and is preferably from 140 ° C to 200 ° C. During the reaction, stirring may or may not be performed.

  The weight average molecular weight with respect to the temperature and the reaction time is determined in advance, and the temperature and time conditions can be adjusted so that a condensate having a desired weight average molecular weight is obtained. It is particularly preferable that the reaction is performed by adjusting the temperature and time conditions so that the weight average molecular weight (Mw) is about 9000 (6000 to 13000).

The stable form of the S element in the synthetic shrinkproofing agent is a sulfonyl group or a sulfonic acid group, and is often contained as a sulfonyl group or a sulfonic acid group. The content of the S element in the synthetic shrinkproofing agent mainly depends on the amount of the S element contained in the sulfonic acid group and the sulfonyl group.
As described above, the S element in the synthetic shrinkproofing agent is often contained as a sulfonyl group or a sulfonic acid group. These groups are hydrophilic groups having strong polarity, and these groups tend to appear on the surface of the colloidal particles formed by the synthetic shrinkage preventive agent in the electrolytic solution due to electrostatic repulsion between the groups. . This limits the association of the synthetic preservative and reduces the size of the colloidal particles formed by the synthetic preservative, in other words, the colloidal particle size of the synthetic preservative.

In order to reduce the average colloid particle diameter in sulfuric acid of the synthetic shrinkproofing agent, for example, the amount of a hydrophilic functional group (sulfonyl group, sulfonic acid group, hydroxyl group, etc.) per molecule of a compound having a plurality of phenolic hydroxyl groups is determined. More is effective.
In order to measure the average colloidal particle diameter of the synthetic preservative, an aqueous solution of the synthetic preservative having a concentration of 1 to 10 mg / mL is diluted 20 times by volume with sulfuric acid having a specific gravity of 1.26 to obtain a specific gravity of 1. 25 solution of sulfuric acid. A sample diluted 20-fold with sulfuric acid was measured, for example, using a laser diffraction / scattering type particle size distribution analyzer LA-950V2 manufactured by HORIBA, Ltd. at 25 ° C. using a batch-type cell while stirring with a magnetic stirrer. , The volume-based average colloid particle size is determined. Note that coexisting ions such as lead ions, aluminum ions, and sodium ions hardly affect the measured value of the average colloid particle size.
Note that the aqueous solution of the synthetic shrinkproofing agent is, for example, to take out the electrode material from the negative electrode plate of the lead storage battery, wash with water to remove sulfuric acid, and then dissolve in an alkali such as a 1.0 M NaOH aqueous solution to extract the synthetic shrinkproofing agent It can be obtained by:

  The content of the S element of the synthetic shrinkage preventive agent can be adjusted by the use ratio of a compound such as bisphenol S or naphthalene sulfonic acid, the conditions of sulfonation, and the like.

3.3.3 Identification of Type of Synthetic Precursor The type of synthetic anti-shrinkage agent in the negative electrode material is specified as follows. The fully charged lead-acid battery is disassembled, the negative electrode plate is taken out, and the sulfuric acid content is removed by washing with water, followed by drying. The negative electrode material containing the active material is separated from the negative electrode plate, and the negative electrode material is immersed in a 1 mol / L aqueous solution of NaOH to extract a synthetic shrinkproofing agent. The solution obtained by removing insoluble components from the extract by filtration is desalted, concentrated and dried to obtain a powder sample. For desalting, a desalting column or an ion exchange membrane is used.
The infrared spectroscopy spectrum measured using the powder sample of the organic preservative obtained in this way or the powder sample is diluted with distilled water, the ultraviolet-visible absorption spectrum measured with an ultraviolet-visible spectrophotometer, and diluted with a predetermined solvent such as heavy water. Then, by using information obtained from the NMR spectrum and the like of the obtained solution in combination, the type of the organic shrinking agent is specified.
Note that the supplementary charging conditions for making the battery fully charged are as follows.
(1) In the case of a liquid battery, constant current charging is performed in a water bath at 25 ° C. at 0.2 CA until the voltage reaches 2.5 V / cell, and then constant current charging is performed at 0.2 CA for 2 hours.
(2) In the case of a VRLA battery (control valve type lead storage battery), a constant current and constant voltage charge of 0.2 CA, 2.23 V / cell is performed in an air tank at 25 ° C., and the charge current during the constant voltage charge is 1 mCA or less. When it becomes, charging ends.
1 CA in this specification is a current value at which the nominal capacity of the battery is discharged in one hour. For example, for a battery having a nominal capacity of 30 Ah, 1 CA is 30 A, and 1 mCA is 30 mA.

3.3.4 Measurement of Content of Synthetic Shrinking Agent The content of the synthetic shrinking agent in the negative electrode material is measured as follows.
The fully charged lead-acid battery is disassembled, the negative electrode plate is taken out, and the sulfuric acid content is removed by washing with water, followed by drying. The negative electrode material is separated from the negative electrode plate, and 100 g of the negative electrode material is immersed in 300 mL of a 1 mol / L aqueous solution of NaOH to extract a synthetic shrinkproofing agent. After removing insoluble components from the extract by filtration, an ultraviolet-visible absorption spectrum is measured, and the content of the synthetic shrinkage-preventing agent in the negative electrode material is measured using a calibration curve prepared in advance.
When obtaining the battery of another company and measuring the content of the synthetic shrink agent, if the same synthetic shrink agent cannot be used in the calibration curve because the structural formula of the synthetic shrink agent cannot be strictly specified, the By creating a calibration curve using a synthetic shrink agent extracted from the negative electrode of the battery and a separately available synthetic shrink agent that shows similar shapes in the UV-visible absorption spectrum, infrared spectrum, and NMR spectrum, etc. The content of the synthetic preservative is measured using an ultraviolet-visible absorption spectrum.

3.3.5 Measurement of S Element Content in Synthetic Shrink Preventive Agent The S element content (hereinafter, also simply referred to as “S element content”) of the synthetic shrink preventive in the negative electrode active material is measured as follows.
The fully charged lead-acid battery is disassembled, the negative electrode plate is taken out, and the sulfuric acid content is removed by washing with water, followed by drying. The negative electrode material is separated from the negative electrode plate, and the negative electrode material is immersed in a 1 mol / L NaOH aqueous solution to extract the synthetic shrinkage preventive. The solution obtained by removing insoluble components from the extract by filtration is desalted, concentrated and dried to obtain a powder sample. For desalting, a desalting column or an ion exchange membrane is used.
The elemental sulfur in 0.1 g of organic preservative is converted to sulfuric acid by the oxygen combustion flask method. At this time, by burning the powder sample in the flask containing the adsorbent, an eluate in which sulfate ions are dissolved in the adsorbent is obtained. Then, the eluate is titrated with barium perchlorate using trilin as an indicator to determine the S element content in 0.1 g of the powder sample. This S element content is converted into a quantity per 1 g to obtain the S element content in the synthetic shrinkage preventive agent.

3.4 Other Components The negative electrode plate may contain other components other than the above-described components. For example, carbon black, graphite, synthetic resin fiber, BaSO ₄ or the like may be contained.

4. Electrolyte The electrolyte is preferably a sulfuric acid aqueous solution containing sulfuric acid and water. The specific gravity of the electrolyte is not particularly limited. The specific gravity is preferably 1.20 or more and 1.35 or less. The specific gravity of the electrolytic solution is a converted value at 20 ° C.
The electrolytic solution may contain other components such as an alkali metal ion, an alkaline earth metal ion, an aluminum ion, silica, phosphoric acid, and boric acid.
The formation can be performed by charging the electrode group in a state in which the electrode group including the unformed negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the battery case of the lead storage battery. However, the chemical conversion treatment may be performed before assembling the lead storage battery or the electrode group. Chemical formation produces spongy lead.

  Hereinafter, the present invention will be described more specifically with reference to examples.

1. Preparation of Lead-Acid Battery A lead of a negative electrode material was obtained by kneading lead powder, a synthetic shrinkproof agent, carbon black, and BaSO ₄ with water and sulfuric acid. The paste of the negative electrode material was filled in a casting grid made of a Pb-Ca-Sn-based alloy, and aged and dried to obtain an unformed negative electrode plate.
A formaldehyde condensate of bisphenols was used as a synthetic shrinkproofing agent having a sulfur element (S element) content of 3500 to 7000 μmol / g.
The content of the sulfur element (S element) in this organic shrinking agent was adjusted by appropriately changing the ratio of bisphenols A, F, and S and the degree of sulfonation.
Further, in the tables and figures, 0 mass% of the synthetic shrinkproofing agent indicates that containing 0.1 mass% of lignin.

Lead powder, red lead, and synthetic resin fibers were kneaded with water and sulfuric acid to obtain a paste of a positive electrode material. This paste was filled into a casting grid made of a Pb-Ca-Sn-based alloy, and aged and dried to obtain an unformed positive electrode plate.
Then, a 2 V lead-acid battery having a nominal capacity of 500 Ah (20 hour rate) was manufactured using the negative electrode plate and the positive electrode plate.
The density of the negative electrode material in a fully charged state was measured by the above-described method using an automatic porosimeter and an automatic pore IV9505 manufactured by Shimadzu Corporation.
The total pore volume and pore distribution of the positive electrode material in a fully charged state were determined by using an automatic porosimeter, Autopore IV9505 manufactured by Shimadzu Corporation at a contact angle of 130 °, a surface tension of 484 dyn / cm, and a pore diameter of 170 to 0. It was measured in the range of .0055 μm.
The synthetic shrinkproofing agent was adjusted to have the composition shown in Tables 1 to 4 described below with respect to 100 mass% of the negative electrode material in a fully charged state after chemical formation.
Regarding the ratio of the amount of the synthetic organic shrinkage agent in the negative electrode material, the value obtained by separating and quantifying the negative electrode taken out of the manufactured battery by the above-mentioned method is somewhat different from the ratio mixed at the time of manufacturing the electrode. Becomes In the examples of the present invention, the content (μmol / g) of the sulfur element (S element) in the organic preservative is 600, 3500, 4000, 4500, 5000, 5500, 6000, 6500, and 7000.
The following ratio R was determined for each one of the batteries.
A = mass ratio (mass%) of the synthetic shrinkproofing agent to the negative electrode material, which was separated and quantified by the above-described method from the negative electrode taken out of the manufactured battery.
B = mass ratio (mass%) of the synthetic shrinkproofing agent mixed at the time of battery production to the negative electrode material
R = A / B
The content (mass%) of the synthetic shrinkproofing agent in the negative electrode material shown in Tables 1 to 5 and FIGS. mass%) multiplied by the above-mentioned R obtained for the batteries having the same content of sulfur element (S element) in the synthetic shrinkage preventive agent.
Regarding the amount of S element (μmol / g) in the synthetic shrinkproofing agent, it was confirmed that there was no difference between the value before mixing with the negative electrode material and the value measured by disassembling and extracting from the battery.
(Therefore, the amount of the S element (μmol / g) in the synthetic shrink proofing agents described in Tables 1 to 4 and FIGS. Value is described.)

2. Performance Evaluation Test 2.1 Cycle Life Test (40 ° C, DoD 70%)
The cycle life test was performed under the following conditions. After the discharging of [1], the normal charging of [2] is performed. This is one cycle. Also, every three cycles, after [2] normal charging, [3] equal charging is performed. The life determination condition was a point in time when the discharge end voltage was lower than 1.7 V during the discharge of [1].

[1] Discharge: 40 ° C., constant current 0.2 CA × 3.5 h
[2] Normal charging: 40 ° C., 2.42 V constant voltage (Imax = 0.2 CA),
Charged electricity / discharge capacity = 1.02
[3] Uniform charging (every 6 cycles): 40 ° C., 2.42 V constant voltage (Imax = 0.2 CA) × 8 h

The capacity test was carried out at the initial stage and about every 500 cycles under the following conditions. In the initial stage, the measurement was performed in a fully charged state after formation, and the measurement was performed after approximately 500 cycles after uniform charging.
Discharge: 25 ° C, 0.2 CA, discharge end voltage 1.75V

3. Results The configuration of each lead storage battery and the results of the performance evaluation are shown in Tables 1 to 4, and graphs obtained from the data in Tables 1 to 4 are shown in FIGS. 1 to 4 correspond to Table 1, FIGS. 5 to 6 correspond to Table 2, FIGS. 7 to 8 correspond to Table 3, and FIG. 9 corresponds to Table 4.

FIG. 1 is a graph showing the number of life cycles when the total pore volume of the positive electrode material is changed. In addition, as for the pore diameter in all the pores of the positive electrode material in a fully charged state, the ratio occupied by pores of 1.2 μm or more is 15 to 20 vol%, and the requirement of 35 vol% or less is satisfied. .
From FIG. 1, when the negative electrode material contains a synthetic shrinkproofing agent, and when the total pore volume of the fully charged positive electrode material is 0.08 to 0.16 mL / g, the life cycle number is good. Was confirmed.

FIG. 2 is a graph showing the initial capacity when the total pore volume of the positive electrode material is changed. In addition, as for the pore diameter in all the pores of the positive electrode material in a fully charged state, the ratio occupied by pores of 1.2 μm or more is 15 to 20 vol%, and the requirement of 35 vol% or less is satisfied. .
Generally, when a synthetic shrinkage-preventing agent is contained in the negative electrode material, the initial capacity tends to be significantly reduced. From the results in FIG. 2, it can be seen that even when the negative electrode material contains a synthetic contracting agent, when the total pore volume of the fully charged positive electrode material is 0.10 to 0.16 mL / g, the initial capacity It was confirmed that the decrease was suppressed.

FIG. 3 is a graph showing the number of life cycles when the proportion of pores having a diameter of 1.2 μm or more in all the pores of the positive electrode material is changed. The total pore volume of the positively charged positive electrode material is 0.12 to 0.14 mL / g, which satisfies the requirement of 0.08 to 0.16 mL / g.
The following results were obtained when the negative electrode material contained a synthetic shrinkproofing agent. That is, it was confirmed that when the proportion of the pores having a diameter of 1.2 μm or more was 35 vol% or less, the life cycle number was very good as compared with the case where the synthetic shrinkproofing agent was not contained.

FIG. 4 is a graph showing an initial capacity when the ratio of pores having a diameter of less than 0.1 μm in all the pores of the positive electrode material is changed. In addition, the total pore volume (cumulative pore volume) of the positive electrode material in a fully charged state is 0.12 to 0.14 mL / g, and satisfies the requirement of 0.08 to 0.16 mL / g. I have. As for the pore diameter in all the pores of the positive electrode material in a fully charged state, the ratio of pores of 1.2 μm or more is set to 20 to 25 vol%, which satisfies the requirement of 35 vol% or less. .
Generally, when a synthetic shrinkage-preventing agent is contained in the negative electrode material, the initial capacity tends to be significantly reduced. From the results of FIG. 4, it was confirmed that even when the synthetic shrinkage-preventing agent was contained, the decrease in the initial capacity was suppressed under predetermined conditions when the ratio of pores smaller than 0.1 μm was 40 vol% or less. Was.

  FIG. 5 is a graph showing the initial capacity when the content of the synthetic shrinkproofing agent is changed. Each of the positive electrode materials A, B, and C is (1) a requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) a pore of 1.2 μm or more. It satisfies all the requirements that the ratio is 35 vol% or less, and (3) the requirement that the ratio of pores smaller than 0.1 μm is 40 vol% or less. When the positive electrode materials A, B, and C satisfying all of these requirements are used, in any case, the content of the synthetic shrinkproofing agent in the fully charged negative electrode material is 0.05 mass. % To 0.3 mass%, it was confirmed that the decrease in the initial capacity was suppressed.

  FIG. 6 is a graph showing the number of life cycles when the content of the synthetic shrinkproofing agent is changed. Each of the positive electrode materials A, B, and C is (1) a requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) pores of 1.2 μm or more are occupied. It satisfies all the requirements that the ratio is 35 vol% or less, and (3) the requirement that the ratio of pores smaller than 0.1 μm is 40 vol% or less. When the positive electrode materials A, B, and C satisfying all of these requirements are used, in any case, the content of the synthetic shrinkproofing agent in the fully charged negative electrode material is 0.05 mass. % Or more and 0.3 mass% or less, it was confirmed that the life cycle number was good.

  FIG. 7 is a graph showing the initial capacity when the content of the sulfur element (S element) in the synthetic shrinkage preventive agent is changed. Each of the positive electrode materials A, B, and C is (1) a requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) pores of 1.2 μm or more are occupied. It satisfies all the requirements that the ratio is 35 vol% or less, and (3) the requirement that the ratio of pores smaller than 0.1 μm is 40 vol% or less. When the positive electrode materials A, B, and C satisfying all of these requirements are used, in any case, the content of the sulfur element (S element) in the fully charged synthetic shrinkage preventive agent is reduced. It was confirmed that the initial capacity was high at 4000 μmol / g or more and 6500 μmol / g or less.

  FIG. 8 is a graph showing the number of life cycles when the content of the sulfur element (S element) in the synthetic shrinkproofing agent is changed. Each of the positive electrode materials A, B, and C is (1) a requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) a pore of 1.2 μm or more. It satisfies all the requirements that the ratio is 35 vol% or less, and (3) the requirement that the ratio of pores smaller than 0.1 μm is 40 vol% or less. When the positive electrode materials A, B, and C satisfying all of these requirements are used, in any case, the content of the sulfur element (S element) in the fully charged synthetic shrinkage preventive agent is reduced. It was confirmed that the life cycle number was good at 4000 μmol / g or more and 6500 μmol / g or less.

FIG. 9 is a graph showing the number of life cycles when the density of the negative electrode material is changed. Each of the positive electrode materials A, B, and C is (1) a requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) pores of 1.2 μm or more are occupied. It satisfies all the requirements that the ratio is 35 vol% or less, and (3) the requirement that the ratio of pores smaller than 0.1 μm is 40 vol% or less. When the positive electrode materials A, B, and C satisfying all these requirements are used, the density of the fully charged negative electrode material is not less than 2.6 g / cm ^{3 and} 4 in any case. It was confirmed that the life cycle number was good at 0.0 g / cm ³ or less.

Here, the above experimental results will be considered.
In general, it is considered that by containing a synthetic shrinkage preventive in the negative electrode material, it is possible to suppress the contraction of the negative electrode material due to the charge-discharge cycle at a high temperature and improve the deterioration of the discharge performance. .
On the other hand, if the synthetic shrinkproofing agent elutes from the negative electrode plate and acts on the positive electrode material, the softening of the positive electrode material is promoted, and the life performance is reduced.
However, as in the lead storage battery of one embodiment of the present invention, (1) the requirement that the total pore volume of the positive electrode material is 0.08 to 0.16 mL / g, and (2) the pore size of 1.2 μm or more When a positive electrode material satisfying the requirement of occupying 35 vol% or less is applied, the softening of the positive electrode material can be significantly improved, and both improvement in discharge performance and long life can be achieved. The reason can be inferred as follows.

The factor that the synthetic shrinkage agent acts on the positive electrode material to promote softening is that the colloidal particles of the synthetic shrinkage agent enter the pores of the positive electrode material and charge / discharge reduces the adhesion between the positive electrode active materials. Therefore, if the pore diameter of the positive electrode material is less than 1.2 μm, it is considered that the softening is not promoted because the colloid particles hardly penetrate.
The softening inhibitory effect described above was observed in a positive electrode material in which the proportion of pores of 1.2 μm or more occupied 35 vol% or less, more preferably 25 vol% or less. However, if the volume occupied by pores smaller than 0.1 μm exceeds 40 vol%, the discharge capacity is reduced. To maintain the discharge performance, the volume occupied by pores smaller than 0.1 μm is 40 vol% or less. Preferably, there is.

  As a synthetic shrinkproofing agent, even when a naphthalene shrinking agent such as a condensate of β-naphthalenesulfonic acid with formaldehyde is used, (1) the total pore volume of the positive electrode material is 0.08 to 0 If the ratio of pores having a diameter of 1.2 μm or more was 35 vol% or less with respect to the pore diameter in all the pores of the positive electrode material, a bisphenol-based contracting agent was used. The same effect as in the case is obtained.

  The invention is not limited to the embodiments described above with reference to the drawings.

  The present invention can be widely applied to lead-acid batteries having a good life.

Claims (5)

A positive electrode plate,
A negative electrode plate,
And a lead-acid battery comprising:
The positive electrode plate includes a positive electrode material,
The negative electrode plate includes a negative electrode material,
The negative electrode material contains a synthetic shrinkproofing agent,
The total pore volume of the positive electrode material in a fully charged state is 0.08 to 0.16 mL / g,
A lead-acid battery in which a ratio of pores having a diameter of 1.2 μm or more to 35 vol% or less is a pore diameter in all pores of the positive electrode material in a fully charged state.   2. The lead storage battery according to claim 1, wherein a ratio of pores having a pore diameter of less than 0.1 μm is 40 vol% or less in a pore diameter of all pores of the positive electrode material in a fully charged state.   3. The lead-acid battery according to claim 1, wherein the negative electrode material contains the synthetic shrinking agent in an amount of 0.05 mass% or more and 0.3 mass% or less with respect to 100 mass% of the negative electrode material in a fully-charged state. .   The lead storage battery according to any one of claims 1 to 3, wherein the content of the sulfur element (S element) in the synthetic shrinkproofing agent is from 4000 µmol / g to 6500 µmol / g. The density of the negative electrode material, a lead acid battery according to any one of claims 1 to 4 2.6 g / cm ³ or more 4.0 g / cm ³ or less in a fully charged state.