JP6729140B2 - Control valve type lead-acid battery - Google Patents

Description

The present invention relates to a valve-regulated lead-acid battery.

Controlled valve lead-acid battery (VRLA battery) that uses a so-called oxygen cycle, in which an electrolyte solution is held in a fine glass mat separator (retainer mat) and oxygen gas generated at the positive electrode is reduced to water on the negative electrode active material. In recent years, due to its ease of maintenance, it has been widely used for stationary applications and the like.
Normally, in a control valve type lead-acid battery for standby use, a plurality of batteries are built in a rack and connected in series to be used (see Patent Document 1). Therefore, the battery is very heavy, and from the viewpoint of earthquake resistance, the installation environment and the design of the battery rack are restricted, so that the weight of the battery is required to be reduced.

JP, 2006-049025, A

However, if the negative electrode material is made lighter by lowering the density, the high temperature accelerated float life test may not reach the expected life of 13 years at 25°C. This was because the positive electrode became insufficiently charged due to the decrease in the float current.

The present invention has been made in view of the above conventional circumstances, and an object of the present invention is to solve the above problems and to provide a control valve type lead storage battery having a long life.

The inventors of the present invention have developed a novel control valve type lead-acid battery as a result of intensive studies in view of the above-mentioned conventional techniques.
Then, they found the fact that this new valve-regulated lead-acid battery has a long life. The present invention has been made based on this finding.

That is, the control valve type lead-acid battery according to one aspect of the present invention,
A positive electrode plate,
Negative electrode plate,
A control valve type lead-acid battery including an electrolytic solution,
The negative electrode plate includes a negative electrode material,
The negative electrode material contains a synthetic anti-shrink agent of 0.05 mass% or more and 0.3 mass% or less and carbon black of 0.05 mass% or more and 0.5 mass% or less with respect to 100 mass% of the fully charged negative electrode material. ,
The density of the negative electrode material is 2.5 g/cm ³ or more and 4.0 g/cm ³ or less,
It is a valve-regulated lead-acid battery in which the utilization factor of the negative electrode material represented by the following formula (1) is 30% or more and 49% or less.

Negative electrode material utilization rate=(nominal capacity/negative electrode material theoretical capacity)×100 (1)

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

It is a graph which shows float life years when the content of carbon (carbon black) is changed. It is a graph which shows the float life years when the content of a synthetic shrink-proof agent is changed. It is a graph which shows the initial capacity when the content of the synthetic shrink-proof agent is changed. It is a graph which shows the float life years when the density of a negative electrode material is changed. It is a graph which shows the float life years when the density of a negative electrode material is changed. It is a graph which shows the float lifetime in the case of changing a negative electrode material utilization rate. It is a graph which shows the initial capacity when the negative electrode material utilization rate is changed. It is a graph which shows the float life years when the content of the sulfur element (S element) in a synthetic shrink-proof agent is changed.

A preferred embodiment of the present invention will be described.

1. Control valve type lead-acid battery The control valve type lead-acid battery of one aspect of the present invention includes a positive electrode plate, a negative electrode plate, and an electrolytic solution. The negative electrode plate includes a negative electrode material. The negative electrode material contains a synthetic anti-shrink agent of 0.05 mass% or more and 0.3 mass% or less and carbon black of 0.05 mass% or more and 0.5 mass% or less with respect to 100 mass% of the fully charged negative electrode material. There is. The density of the negative electrode material is 2.5 g/cm ³ or more and 4.0 g/cm ³ or less. The utilization factor of the negative electrode material represented by the following formula (1) is 30% or more and 49% or less.

Negative electrode material utilization rate=(nominal capacity/negative electrode material theoretical capacity)×100 (1)

In addition, the electrode material includes not only the reaction substance but also all other additives. The electrode plate is composed of an electrode material and a current collector. Therefore, the electrode material means the rest of the electrode plate excluding the current collector.

2. Positive Electrode Plate The type of positive electrode plate is not particularly limited. A paste type electrode plate can be used as the positive electrode plate. The paste type electrode plate is, for example, filled with a paste of a positive electrode material containing a positive electrode active material in a collector (lattice body) made of pure lead or a lead alloy for expanding, casting, punching, etc., and then aged and dried. Obtained. The positive electrode material paste 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 positive electrode material in addition to the positive electrode active material.

3. Negative Electrode Plate 3.1 Type of Electrode Plate The type of 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) for expanding, casting, punching or the like made of pure lead or 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 and then 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 control valve type lead-acid battery of one embodiment of the present invention, the density of the negative electrode material is 2.5 g/cm ³ or more and 4.0 g/cm ³ or less, preferably 2.5 g. / cm ³ or more 3.8 g / cm ³ or less, more preferably not more than 2.7 g / cm ³ or more 3.5 g / cm ^3.
This is because when the density of the negative electrode material is within this range, the effect of improving the life performance of the additive can be obtained while suppressing the deterioration of the life performance due to the low density.
The density of the negative electrode material means the value of the bulk density of the negative electrode material after chemical conversion, 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 electrolytic solution in the negative electrode plate. Then, the negative electrode material is separated from the negative plate to obtain an uncrushed measurement sample. Put the sample in the measuring container, evacuate it, and then fill it with mercury at a pressure of 0.5 to 0.55 psia, measure the bulk volume of the negative electrode material, and divide the mass of the measurement sample by the bulk volume to obtain the negative electrode. Find the bulk density of the material. The volume obtained by subtracting the injection volume of mercury from the volume of the measurement container is defined as the bulk volume.

3.3 Synthetic anti-shrink agent 3.3.1 Content of synthetic anti-shrink agent In the control valve type lead-acid battery of this embodiment, 0.05 mass% or more and 0.3 mass% or less with respect to 100 mass% of the fully charged negative electrode material. It contains a synthetic anti-shrink agent. The content of the synthetic anti-shrink agent is preferably 0.1 mass% or more and 0.3 mass% or less, and more preferably 0.1 mass% or more and 0.2 mass% or less with respect to 100 mass% of the fully charged negative electrode material. .. When the synthetic shrinkproofing agent is in this range, the initial capacity of the valve regulated lead acid battery tends to be improved.

3.3.2 Details of Synthetic Anti-shrink Agent The synthetic anti-shrink agent in the present embodiment is not particularly limited as long as it is an artificially synthesized anti-shrink agent. The synthetic anti-shrink agents may be used alone or in combination of two or more.
Examples of synthetic shrink-proofing agents include reaction products of compounds having a plurality of phenolic hydroxyl groups with aldehydes, reaction products of naphthalene compounds with aldehydes, and the like. In addition, polyacrylic acid, a polymer of acrylamide/tert-butyl/sulfonic acid Na (ATBS polymer: ATBS is a registered trademark), N,N′-(sulfonyldi-4,1-phenylene)bis(1,2,3 , 4-tetrahydro-6methyl-2,4-dioxopyrimidine-5-sulfonamide) can also be used.
In the polymer of polyacrylamide/tert-butyl/Na sulfonate, the ratio of the basic skeleton to the amount of the sulfonic acid group is not particularly limited, but the ratio of the basic skeleton to the amount of the sulfonic acid group is 1:1. preferable.

The compound having a plurality of phenolic hydroxyl groups is not particularly limited as long as it has two or more phenolic hydroxyl groups. These compounds may be used alone or in combination of two or more.
Bisphenols are preferably used as the compound having a plurality of phenolic hydroxyl groups. 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, bisphenol Z. Etc. are illustrated. These may be used alone or in combination of two or more.

The aldehydes are not particularly limited. Examples of 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 it has high reactivity with a compound having a plurality of phenolic hydroxyl groups.

Further, a sulfonic acid group (sulfo group) may be further introduced into the reaction product of the compound having a plurality of phenolic hydroxyl groups and the aldehyde. By introducing a sulfonic acid group, the amount of elemental sulfur (S element) in the synthetic shrinkproofing agent can be increased.
The sulfonic acid group need not be directly bonded to the aromatic ring of the compound having a plurality of phenolic hydroxyl groups (for example, the phenyl group of bisphenols). For example, an alkyl chain may be bonded to the aromatic ring and a sulfonic acid group may be bonded to this alkyl chain.
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.

The content of elemental sulfur (S element) in the synthetic shrink-proofing agent is not particularly limited. The content of elemental sulfur (S element) in the synthetic anti-shrink agent is preferably 4000 μmol/g or more and 9000 μmol/g or less, more preferably 5000 μmol/g or more and 8000 μmol/g or less, and further preferably 6000 μmol/g or more It is 8000 μmol/g or less. When the content of the sulfur element (S element) is within this range, the float life of the control valve type lead storage battery tends to be improved. That is, in this range, the elution of the synthetic shrinkproofing agent from the negative electrode plate is suppressed. Therefore, the negative effect resulting from the elution of the synthetic anti-shrink agent, that is, the negative effect of decreasing the initial capacity when the synthetic anti-shrink agent is added is suppressed, and the effect of improving the life performance is enhanced.

The molecular weight of the synthetic shrinkproofing agent is not particularly limited. The weight average molecular weight (Mw) of the synthetic anti-shrink agent is preferably 1,000 or more and 1,000,000 or less, more preferably 1,000 or more and 100,000 or less, and further preferably 1,000 or more and 20,000 or less. This range is preferable from the viewpoint of synthesizing organic substances.
The molecular weight is measured by gel permeation chromatography (GPC). The standard substance used to determine the molecular weight is sodium polystyrene sulfonate.
The molecular weight can be measured using the following devices and conditions.
GPC device: Build-up GPC system
SD-8022/DP-8020/AS-8020/CO-8020/UV-8020 (manufactured by Tosoh Corporation)
Column: TSKgel G4000SWXL, G2000SWXL (7.8 mm I.D.×30 cm) (manufactured by Tosoh Corporation)
Detector: UV detector λ=210nm
Eluent: 1mol/L NaCl: Acetonitrile (7:3)
Flow rate: 1 ml/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 sulfonic acid group-introduced bisphenol A with formaldehyde, a condensate of sulfonic acid group-introduced bisphenol S with formaldehyde, and a condensate of β-naphthalenesulfonic acid with formaldehyde ( Kao Co., Ltd. product name “Demol”) can be preferably used. In addition, when bisphenol S is used, the S element derived from the sulfonic acid group and the sulfonyl group (—SO ₂ —) structure in bisphenol S is present in the synthetic shrink-proofing agent.

Among the synthetic shrink-proofing agents, a condensate of bisphenols is preferable. The condensate of bisphenols is suitable for a control valve type lead storage battery in which a plurality of batteries are connected in series and are constantly float-charged and easily reach a high temperature because their performance is not impaired even when they are exposed to a high temperature environment. Note that the condensate of naphthalene sulfonic acid is suitable for a valve-regulated lead-acid battery in which the liquid-reducing property is important, because the polarization is less likely to become smaller than that of the condensate of bisphenols.

Here, an example of a suitable synthesis method of a condensate of bisphenols will be shown. Bisphenols (bisphenol A, S, F, etc.), formaldehyde and sulfite are mixed to obtain a formaldehyde condensate of bisphenols. At this time, the amount of S of the shrink-proofing 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 contained in approximately equimolar amounts and reacted. In addition, since polymerization proceeds under alkaline conditions, it is preferable to use NaOH or the like as a pH adjuster and set the pH to about 12 (pH=10 to 13).

The reaction temperature is not particularly limited and is preferably 140° C. or higher and 200° C. or lower. The reaction may or may not be stirred.

The temperature/time conditions can be adjusted so that the weight average molecular weight with respect to the temperature/reaction time is obtained in advance and a condensate having a desired weight average molecular weight is obtained. Particularly preferably, the temperature and time conditions are adjusted so that the weight average molecular weight (Mw) is about 9000 (6000 to 13000) and the reaction is preferably performed.

The S element in the synthetic shrinkproofing agent is often contained as a sulfonyl group or a sulfonic acid group. The content of S element in the synthetic shrink-proofing agent is mainly the amount of S element contained in the sulfonic acid group and the sulfonyl group.
In addition, as described above, the S element in the synthetic shrink-proofing agent is often contained as a sulfonyl group or a sulfonic acid group. These groups are hydrophilic groups with strong polarity, and due to electrostatic repulsion between these groups, in the electrolyte, these groups tend to appear on the surface of the colloidal particles formed by the synthetic shrinkproofing agent. .. As a result, the association of the synthetic anti-shrink agent is restricted, and the size of the colloid particles formed by the synthetic anti-shrink agent, in other words, the diameter of the colloid particle of the synthetic anti-shrink agent is reduced.

Regarding the synthetic anti-shrink agent, in order to reduce the average colloidal particle size in sulfuric acid, 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 set. It is effective to do more.
In order to measure the average colloidal particle size of the synthetic anti-shrink agent, an aqueous solution of the synthetic anti-shrink agent having a concentration of 1 to 10 mg/mL was diluted 20 times by volume with sulfuric acid having a specific gravity of 1.26 to give a specific gravity of 1. 25 solution of sulfuric acid. A sample diluted 20-fold with sulfuric acid is measured, for example, using a laser diffraction/scattering particle size distribution measuring device LA-950V2 manufactured by Horiba Ltd. at 25° C. with a batch stirrer while stirring with a magnetic stirrer. , Find the volume-based average colloidal particle size. Coexisting ions such as lead ions, aluminum ions, and sodium ions have almost no effect on the measured value of the average colloidal particle size.
For example, an aqueous solution of a synthetic shrink-proofing agent is obtained by extracting an electrode material from a negative electrode plate of a lead storage battery, washing with water to remove sulfuric acid, and then dissolving it in an alkali such as 1.0 M NaOH aqueous solution to extract the synthetic shrink-proofing agent. can get.

The S element content of the synthetic shrink-proofing agent can be adjusted by the use ratio of compounds such as bisphenol S and naphthalenesulfonic acid, the sulfonation conditions, and the like.

3.3.3 Specification of Synthetic Strain Retardant Type The specification of the synthetic shrink proof agent in the negative electrode material is performed as follows. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove the sulfuric acid content, and dried. 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 NaOH aqueous solution to extract the synthetic shrinkproofing agent. A solution obtained by removing insoluble components by filtration from the extract is desalted, and then concentrated and dried to obtain a powder sample. A desalting column or an ion exchange membrane is used for desalting. Information obtained from the infrared spectrum and the NMR spectrum measured using the powder sample of the synthetic shrink-proofing agent thus obtained, and the ultraviolet-visible absorption spectrum measured by an ultraviolet-visible spectrophotometer after further diluting the powder sample with distilled water Is used to identify the synthetic anti-shrink agent species.
The supplementary charging conditions for the fully charged state are as follows.
Since the present embodiment is a control valve type lead storage battery (VRLA battery), constant current constant voltage charging of 0.2 CA, 2.23 V/cell is performed in a gas tank at 25° C., and a charging current during constant voltage charging is performed. The charging is terminated when is less than 1 mCA.
1CA in this specification is a current value for discharging the nominal capacity of the battery in 1 hour. For example, in the case of a battery having a nominal capacity of 30Ah, 1CA is 30A and 1mCA is 30mA.

3.3.4 Measurement of content of synthetic shrink-proofing agent The content of the synthetic shrink-proofing 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, washed with water to remove the sulfuric acid content, and dried. 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 NaOH aqueous solution to extract the synthetic shrink-proofing agent. After removing the insoluble component from the extract by filtration, the ultraviolet-visible absorption spectrum is measured, and the content of the synthetic shrinkproofing 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 strain suppressor, if the same synthetic strain suppressor cannot be used in the calibration curve because the structural formula of the synthetic strain suppressor cannot be strictly specified, By preparing a calibration curve using a synthetic shrinkage inhibitor extracted from the negative electrode of the battery and a synthetic shrinkage agent that is separately available and shows a similar shape to the ultraviolet-visible absorption spectrum, infrared spectrum, and NMR spectrum. The content of the synthetic anti-shrinking agent is measured using the visible absorption spectrum.

3.3.5 Measurement of S Element Content in Synthetic Strain Retardant The S element content of the synthetic shrink proof agent in the negative electrode material (hereinafter also simply referred to as “S element content”) is measured as follows.
The fully charged lead-acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove the sulfuric acid content, and dried. 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 shrinkproofing agent. A solution obtained by removing insoluble components by filtration from the extract is desalted, and then concentrated and dried to obtain a powder sample. A desalting column or an ion exchange membrane is used for desalting.
Taking 0.1 g of the powder sample, an eluate obtained by converting the S element in the powder sample into sulfuric acid by the oxygen combustion flask method is obtained. Then, the eluate is titrated with barium perchlorate using trin as an indicator to determine the S element content in 0.1 g of the powder sample. The S element content is converted into a quantity per 1 g to obtain the S element content in the synthetic shrinkproofing agent.

3.4 Carbon black The negative electrode material contains 0.05 mass% or more and 0.5 mass% or less, preferably 0.1 mass% or more and 0.5 mass% or less of carbon black with respect to 100 mass% of the fully charged negative electrode material. doing. Within this range, the liquid reduction amount is suppressed and the life performance is improved.
In the control valve type lead-acid battery of one embodiment of the present invention, the negative electrode material contains a synthetic shrink-proofing agent of 0.05 mass% or more and 0.3 mass% or less with respect to 100 mass% of the fully charged negative electrode material. , And a combination containing 0.05 mass% or more and 0.5 mass% or less of carbon black is an essential requirement. By satisfying the requirement of this combination, it becomes possible to improve the shortage of charge of the positive electrode plate without changing the conductivity or the liquid reducing property of the negative electrode plate.

The carbon black is not particularly limited, and various carbon blacks can be used. Examples of carbon black include furnace black, channel black, thermal black, acetylene black, and Ketjen black. These may be used alone or in combination of two or more.

3.5 Other Components The negative electrode plate may contain components other than the above components. For example, synthetic resin fiber or BaSO ₄ may be contained.

4. Negative electrode material utilization rate In the control valve type lead storage battery according to one embodiment of the present invention, the negative electrode material utilization rate represented by the following formula (1) is 30% or more and 49% or less, preferably 32% or more and 49% or less. And more preferably 35% or more and 45% or less.
This is because when the utilization rate of the negative electrode material is within this range, deterioration of the life performance due to the high utilization rate of the negative electrode material is suppressed, and the effect of improving the life performance of the additive is obtained.

Negative electrode material utilization rate=(nominal capacity/negative electrode material theoretical capacity)×100 (1)

5. Electrolytic Solution The electrolytic solution is preferably a sulfuric acid aqueous solution containing sulfuric acid and water. The specific gravity of the electrolytic solution 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 electrolyte solution may contain other components such as alkali metal ions, alkaline earth metal ions, aluminum ions, silica, phosphoric acid and boric acid.

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

1. Preparation of Controlled Valve Lead Acid Battery Lead powder, synthetic shrinkproof agent, carbon black, and BaSO ₄ were kneaded with water and sulfuric acid to prepare a negative electrode material paste. The negative electrode material paste was filled in a casting grid made of a Pb-Ca-Sn alloy and aged and dried to obtain an unformed negative electrode plate.
The synthetic anti-shrink agent and the carbon black were adjusted to have the compositions shown in Tables 1 to 6 below with respect to 100 mass% of the fully charged negative electrode material. Further, the density and the utilization rate of the negative electrode material were adjusted to the values shown in Tables 1 to 6 described later.
Regarding the ratio of the amount of the synthetic shrinkproofing agent to the negative electrode material, the value obtained by quantitatively separating from the negative electrode taken out from the manufactured battery by the above-mentioned method is a value that is somewhat different from the ratio mixed at the time of manufacturing the electrode. Become. In the examples of the present invention, the content of the sulfur element (S element) in the synthetic shrinkproofing agent (μmol/g) is 3000, 4000, 5000, 6000, 7000, 8000, 9000, 10000, respectively. In, the following ratio R was obtained.
A=mass ratio (mass%) of the content of the synthetic shrinkproofing agent separated and quantified by the above-mentioned method from the negative electrode taken out from the manufactured battery to the negative electrode material
B=mass ratio (mass%) of the synthetic shrinkproof agent mixed at the time of battery preparation to the negative electrode material
R=A/B
The content (mass%) of the synthetic shrink-proofing agent in the negative electrode material shown in Tables 1 to 6 is the mass ratio (mass%) of the mixed synthetic shrink-proofing agent to the negative electrode material at the time of battery production in each battery, It is a value obtained by multiplying the above-mentioned R obtained for batteries having the same sulfur element (S element) content in the synthetic shrink-proofing agent.
As for the amount of S element (μmol/g) in the synthetic shrink-proofing agents shown in Tables 1 to 6, the value obtained by measuring each synthetic shrink-proofing agent before being mixed as the negative electrode material is described.

As the synthetic shrinkproofing agent, a formaldehyde condensate of bisphenols was used.
The content of elemental sulfur (S element) in this synthetic shrink-proofing agent was adjusted by appropriately changing the ratio of bisphenols A, F and S and the degree of sulfonation. The amounts of elemental sulfur (S element) in the synthetic shrink-proofing agent used in each experimental example are shown in Tables 1 to 6 below.
In the tables and figures, the synthetic anti-shrinking agent 0.00mass% shows the addition of lignin of 0.10mass%.

Lead powder, red lead, and synthetic resin fiber were kneaded with water and sulfuric acid to obtain a positive electrode material paste. This paste was filled in a casting grid made of a Pb-Ca-Sn alloy and was aged and dried to obtain an unformed positive electrode plate.
Then, a lead storage battery was manufactured using the negative electrode plate and the positive electrode plate.
The density of the negative electrode material was measured by the above method using an automatic porosimeter, Autopore IV9505 manufactured by Shimadzu Corporation.
In all the batteries shown in Tables 1 to 6, the positive electrode had the same specifications. Therefore, the amount of positive electrode material is the same in all batteries. The nominal capacities of these batteries were all 200 Ah.
The negative electrode material utilization rates of the batteries shown in Tables 1 to 5 were adjusted by changing the density of the negative electrode material. The nominal capacities of all the batteries shown in Tables 1 to 5 are constant at 200 Ah, and when the density of the negative electrode material is changed, the theoretical capacity of the negative electrode material changes with a change in the amount of the negative electrode material. The utilization rate can be changed. In the batteries shown in Table 6, the amount of the negative electrode material was changed by changing the number of crosspieces of the negative electrode grid to adjust the volume filled with the electrode material, thereby changing the utilization rate of the negative electrode material. The nominal capacity of all the batteries shown in Table 6 is constant at 200 Ah, and the theoretical capacity of the negative electrode material changes with a change in the amount of the negative electrode material, so that the utilization rate of the negative electrode material can be changed.

2. Performance evaluation test 2.1 Initial capacity The battery capacity at the time of constant current discharge from a fully charged state at 25° C. and 0.1 CA until reaching 1.8 V/cell is measured.

2.1 Float life In a 60°C environment, when float charging is performed under a constant voltage condition of 2.23V/cell and discharged at 25°C and 0.1CA every month until 1.8V/cell is reached. Measure the battery capacity of. Then, after measuring the battery capacity, a recovery charge of 120% of the amount of electricity with respect to the discharge capacity is performed, the time when the battery capacity becomes 80% or less of the nominal capacity is measured as the life, and the measured 60°C The number of years multiplied by 2 to the power of 3.5 was calculated as the number of years of life at 25°C (assuming that the number of years of life doubles every 10°C decrease).

3. Results Tables 1 to 6 show the configuration of the control valve type lead storage battery of each experimental example and the results of performance evaluation, and the graphs derived from Tables 1 to 6 are shown in FIGS. 1 corresponds to Table 1, FIGS. 2 to 3 correspond to Table 2, FIGS. 4 to 5 correspond to Tables 3 and 4, FIGS. 6 to 7 correspond to Table 6, and FIG. 8 corresponds to Table. It corresponds to 5.

FIG. 1 is a graph showing float life years when the content of carbon black is changed. From this graph, it was confirmed that the float life was good when the negative electrode material contained carbon black of 0.05 mass% or more and 0.5 mass% or less. When carbon black is added in an amount of more than 0.5 mass %, the float current increases and the shortage of charge on the positive electrode plate is solved, but it is considered that the liquid reduction amount increases and the life performance decreases.
In addition, in FIG. 1, the content of the synthetic shrinkproofing agent is within the range of the numerical limitation of the present invention.

FIG. 2 is a graph showing the number of years of float life when the content of the synthetic shrink-proofing agent is changed. From this graph, it was confirmed that the float life was good when the negative electrode material contained 0.05 mass% or more and 0.3 mass% or less of the synthetic shrink-proofing agent.
In addition, in FIG. 2, the content of carbon black is within the range of the numerical limitation of the present invention.

FIG. 3 is a graph showing the initial capacity when the content of the synthetic shrink-proofing agent is changed. From this graph, it was confirmed that the reduction of the initial capacity was suppressed when the negative electrode material contained the synthetic shrinkproofing agent of 0.05 mass% or more and 0.3 mass% or less.
In addition, in FIG. 3, the content of carbon black is within the range of numerical values of the present invention.

FIG. 4 is a graph showing the float life years when the density of the negative electrode material is changed. From this graph, it was confirmed that the float life was good when the density of the negative electrode material was 2.5 g/cm ³ or more and 4.0 g/cm ³ or less.
It was also confirmed from FIG. 4 that the float life was good when the utilization rate of the negative electrode material was 30% or more and 49% or less.
In addition, in FIG. 4, the content of the synthetic anti-shrink agent and the content of the carbon black are within the respective numerical limits of the present invention.

FIG. 5 is a graph showing the float life years when the density of the negative electrode material is changed. From this graph, it was confirmed that the float life was good when the density of the negative electrode material was 2.5 g/cm ³ or more and 4.0 g/cm ³ or less.
It was also confirmed from FIG. 5 that the float life was good when the utilization rate of the negative electrode material was 30% or more and 49% or less.
In FIG. 5, the content of the synthetic anti-shrink agent and the content of the carbon black are within the respective numerical limits of the present invention.

FIG. 6 is a graph showing float life years when the negative electrode material utilization rate is changed. From this graph, it was confirmed that the float life was good when the utilization rate of the negative electrode material was 30% or more and 49% or less.
On the other hand, it was confirmed that when the utilization rate of the negative electrode material increased, the float current decreased, the positive electrode plate became insufficiently charged, and the float life performance tended to decrease.
In FIG. 6, the content of the synthetic anti-shrink agent, the content of carbon black, and the density of the negative electrode material are within the respective numerical limits of the present invention.

FIG. 7 is a graph showing the initial capacity when the utilization rate of the negative electrode material is changed. From this graph, it was confirmed that the initial capacity can be sufficiently secured even when the utilization rate of the negative electrode material is 30% or more and 49% or less.
In FIG. 7, the content of the synthetic anti-shrink agent, the content of carbon black, and the density of the negative electrode material are within the respective numerical limits of the present invention.

FIG. 8 is a graph showing the float life years when the content of the sulfur element (S element) in the synthetic anti-shrink agent is changed. From this graph, it was confirmed that the elemental sulfur (S element) in the synthetic shrink-proofing agent had a good float life when it was 4000 μmol/g or more and 9000 μmol/g or less.
In FIG. 8, the content of the synthetic anti-shrink agent, the content of carbon black, the density of the negative electrode material and the utilization rate of the negative electrode material are within the respective numerical limits of the present invention.
From the above, (1) the negative electrode material is 0.05 mass% or more and 0.3 mass% or less of the formaldehyde condensate of bisphenols, and 0.05 mass% or more and 0.5 mass% with respect to 100 mass% of the fully charged negative electrode material. % Or less, (2) the density of the negative electrode material is 2.5 g/cm ³ or more and 4.0 g/cm ³ or less, and (3) the negative electrode material utilization rate is 30% or more. It was confirmed that by satisfying all the requirements of 49% or less, it is possible to improve the insufficient charge of the positive electrode plate without changing the conductivity or the liquid reducing property of the negative electrode plate.

Even when a naphthalene-based shrinkproofing agent such as a condensation product of β-naphthalenesulfonic acid with formaldehyde is used as the synthetic shrinkproofing agent, (1) the negative electrode material is 100% by mass of the fully charged negative electrode material. On the other hand, it contains 0.05 mass% or more and 0.3 mass% or less of a naphthalene-based shrinkproofing agent and 0.05 mass% or more and 0.5 mass% or less of carbon black. (2) The density of the negative electrode material is 2. By satisfying all the requirements of 5 g/cm ³ or more and 4.0 g/cm ³ or less, and (3) utilization rate of the negative electrode material of 30% or more and 49% or less, a bisphenol-based shrinkproofing agent is used. The same effect can be obtained as if it had been.

The invention is not limited to the embodiments described by the above description and drawings.

INDUSTRIAL APPLICABILITY The present invention can be widely applied to a valve regulated lead-acid battery having a good life.

Claims (2)

A positive electrode plate,
Negative electrode plate,
A control valve type lead-acid battery including an electrolytic solution,
The negative electrode plate includes a negative electrode material,
The negative electrode material contains a synthetic anti-shrink agent of 0.05 mass% or more and 0.3 mass% or less and carbon black of 0.05 mass% or more and 0.5 mass% or less with respect to 100 mass% of the fully charged negative electrode material. ,
The density of the negative electrode material is 2.5 g/cm ³ or more and 4.0 g/cm ³ or less,
A valve-regulated lead-acid battery having a utilization factor of the negative electrode material represented by the following formula (1) of 30% or more and 49% or less.

Negative electrode material utilization rate=(nominal capacity/negative electrode material theoretical capacity)×100 (1)
The control valve type lead storage battery according to claim 1, wherein the content of elemental sulfur (S element) in the synthetic shrink-proofing agent is 4000 μmol/g or more and 9000 μmol/g or less.