WO2018020937A1

WO2018020937A1 - Lead storage cell

Info

Publication number: WO2018020937A1
Application number: PCT/JP2017/023566
Authority: WO
Inventors: 泰如 ▲浜▼野
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2016-07-29
Filing date: 2017-06-27
Publication date: 2018-02-01
Also published as: JP2018018799A; JP6756181B2

Abstract

Provided is a lead storage cell provided with: a negative electrode plate; a positive electrode plate; a separator interposed between the negative electrode plate and the positive electrode plate; and an electrolyte. The negative electrode plate is provided with a negative electrode collector and a negative electrode material. The negative electrode material contains an organic shrink-proofing agent that contains elemental sulfur, and a fibrous material. The density of the negative electrode material is 2.5 g/cm³-4.0 g/cm³. The elemental sulfur content of the organic shrink-proofing agent is greater than 3,000 µmol/g.

Description

Lead acid battery

The present invention relates to a lead storage battery.

Lead acid batteries are used for various purposes in addition to automobiles and industries. The lead acid battery includes a negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the positive electrode plate, and an electrolytic solution containing sulfuric acid. The thickness of the positive electrode plate and the negative electrode plate of the lead acid battery for automobiles is usually about 1 mm. On the other hand, for industrial use, a large lead-acid battery having a thicker electrode plate is also used.

The negative electrode plate includes a negative electrode current collector and a negative electrode material, and the negative electrode material includes an active material (lead or lead sulfate) that develops capacity by an oxidation-reduction reaction and various additives. For example, the discharge performance of a lead storage battery can be improved by adding an organic shrinkage agent to the negative electrode material.

As an organic shrinking agent, lignin derived from natural products is generally used. On the other hand, Patent Document 1 proposes to use a bisphenol condensate as an organic shrinking agent. In Patent Document 1, the density of the negative electrode material is controlled in the range of 2.8 to 3.8 g / cm ³ .

The life performance of lead-acid batteries is also affected by the dropout of the positive electrode material from the positive electrode plate. On the other hand, Patent Document 2 proposes that the active material group of the electrode plate includes a crimped fiber.

Patent Document 3 teaches a large lead-acid battery with an electrode plate height of more than 1 m, an anode plate having a height of 120 cm and a thickness of 0.74 cm, and a cathode plate having a height of 120 cm and a thickness of 0.35 cm. And a large lead-acid battery.

International Publication No. 2015/181865 Pamphlet JP 2014-49221 A JP 59-186262 A

The density of the negative electrode material of the lead storage battery is 4.0 g / cm ³ or less, and the negative electrode material contains a synthetic organic shrunk agent such as a bisphenol condensate instead of lignin. Capacity reduction can be suppressed. However, as a result of various experiments, a new finding has been found that when a synthetic organic shrinkage agent is used, a voltage drop increases when a lead-acid battery is discharged at a high rate after repeated charge / discharge cycles.

One embodiment of the present invention includes a negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the positive electrode plate, and an electrolyte. The negative electrode plate includes a negative electrode current collector, a negative electrode The negative electrode material includes an organic shrinkage agent containing sulfur element and a fibrous substance, and the negative electrode material has a density of 2.5 g / cm ³ or more and 4.0 g / cm ^{3 or} less, the content of the sulfur element in the organic expander agent is greater than 3000μmol / g, about lead-acid battery.

According to the present invention, when a charge / discharge cycle of a lead storage battery in which the density of the negative electrode material is 2.5 g / cm ³ or more and 4.0 g / cm ³ or less is repeated, the voltage drop during high rate discharge is suppressed. The

1 is a perspective view schematically showing a lead storage battery according to an embodiment of the present invention. It is a front view of the lead acid battery of FIG. FIG. 2B is a cross-sectional view taken along line II-II in FIG. 2A. It is a figure which shows the relationship between the charging / discharging cycle number of a lead storage battery, and the voltage drop at the time of high rate discharge. It is a figure which shows the relationship between the density of a negative electrode material, and the voltage drop at the time of the high rate discharge after 600 cycles progress when a charging / discharging cycle is repeated at normal temperature. The relationship between the density of the negative electrode material when the content of the elemental sulfur in the organic shrinking agent is changed and the voltage drop during high rate discharge after 600 cycles when the charge / discharge cycle is repeated at room temperature. FIG.

The lead acid battery which concerns on 1 aspect of this invention is equipped with a negative electrode plate, a positive electrode plate, the separator interposed between a negative electrode plate and a positive electrode plate, and electrolyte solution. The negative electrode plate includes a negative electrode current collector and a negative electrode material, and the negative electrode material includes an organic shrinking agent containing a sulfur element and a fibrous substance. Here, the density of the negative electrode material is 2.5 g / cm ³ or more and 4.0 g / cm ³ or less, and the content of elemental sulfur in the organic anti-shrink agent is larger than 3000 μmol / g.

When lignin is added as an organic shrunk agent and the density of the negative electrode material is reduced to 4.0 g / cm ³ or less, there is a tendency that the capacity drop associated with the charge / discharge cycle increases. This is presumably because the smaller the density of the negative electrode material, the larger the voids in the negative electrode material, and therefore the more susceptible to the shrinkage of the voids. On the other hand, for example, when a bisphenol condensate is included in the negative electrode material, the shrinkage of the voids is remarkably suppressed, and the capacity reduction accompanying the charge / discharge cycle is suppressed.

However, when the organic shrinkage agent as described above is included in the negative electrode material having a density of 4.0 g / cm ³ or less, the voltage drop increases when the lead-acid battery is discharged at a high rate during the charge / discharge cycle. A phenomenon was found. This is presumably because stress is generated in the negative electrode material due to contraction of the active material accompanying charge / discharge, the bond between the active material particles is broken, and the resistance increases. When the voltage drop becomes large, a large current flows to compensate for the decrease in output, so that the durability of the lead-acid battery decreases. In addition, when the density of negative electrode material exceeds 4.0 g / cm < ³ >, the above remarkable voltage drops are not seen.

On the other hand, when the negative electrode material contains an organic shrinking agent and a fibrous substance, and the content of elemental sulfur in the organic shrinking agent exceeds 3000 μmol / g, particularly 3500 μmol / g or more, further 4000 μmol / g. In the above case, the voltage drop during the high rate discharge is remarkably suppressed. The fibrous substance is considered to suppress the generation of microcracks in the negative electrode plate due to the shrinkage of the negative electrode material. Thereby, it is presumed that a conductive path between the active material particles or between the active material particles and the negative electrode current collector is secured, and a voltage drop during high rate discharge is suppressed.

The effect of increasing the mechanical strength of the negative electrode material having a density of 4.0 g / cm ³ or less can be expected from the fibrous substance. Therefore, the density of the negative electrode material can be considerably reduced. However, from the viewpoint of ensuring the durability of the negative electrode plate and sufficiently suppressing the voltage drop, the density of the negative electrode material is preferably 2.5 g / cm ³ or more, and more preferably 2.7 g / cm ³ or more.

It is known that an organic shrinkage agent having a sulfur element content exceeding 3000 μmol / g has a small colloid particle diameter formed in an aqueous sulfuric acid solution. It is considered that the stress generated between the active material particles due to charge / discharge is easily suppressed by reducing the colloidal particle size of the organic shrinking agent.

The organic shrunk agent is an organic polymer containing a sulfur element, and generally contains one or more, preferably a plurality of aromatic rings in the molecule and a sulfur-containing group. The influence of the organic shrinkage agent on the performance of the lead storage battery does not vary greatly depending on the type of sulfur-containing group. However, among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group which is a stable form is preferable. The sulfonic acid group may exist in an acid form, or may exist in a salt form such as a Na salt.

As a specific example of the organic shrinking agent, a condensate of formaldehyde with a compound having a sulfur-containing group and one or more, preferably two or more aromatic rings is preferable. As the compound having two or more aromatic rings, bisphenols, biphenyls, naphthalenes and the like are preferably used. Bisphenols, biphenyls and naphthalenes are generic names for compounds having a bisphenol skeleton, biphenyl skeleton and naphthalene skeleton, respectively, and each may have a substituent. These may be contained alone in the organic shrinking agent, or a plurality of types may be contained. As bisphenol, bisphenol A, bisphenol S, bisphenol F and the like are preferable. Among them, bisphenol S has a sulfonyl group (—SO ₂ —) in the bisphenol skeleton, so that it is easy to increase the content of elemental sulfur.

The sulfur-containing group may be directly bonded to an aromatic ring such as bisphenols, biphenyls, and naphthalenes. For example, the sulfur-containing group may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group. Further, for example, a monocyclic aromatic compound such as aminobenzenesulfonic acid or alkylaminobenzenesulfonic acid may be condensed with formaldehyde together with a compound having two or more aromatic rings.

Condensates of N, N ′-(sulfonyldi-4,1-phenylene) bis (1,2,3,4-tetrahydro-6-methyl-2,4-dioxopyrimidine-5-sulfonamide) and the like are organic It may be used as an anti-shrink agent.

The content of the organic shrinking agent contained in the negative electrode material does not greatly affect the action of the organic shrinking agent as long as it is within a general range. The content of the organic shrinking agent contained in the negative electrode material is, for example, preferably 0.01% by mass or more and 1% by mass or less, more preferably 0.02% by mass or more and 0.8% by mass or less, 0.05 More preferably, it is at least 0.3% by mass. Here, the content of the organic shrinking agent contained in the negative electrode material is a content in the negative electrode material collected by a method described later from an already formed lead-acid battery in a fully charged state.

The content of elemental sulfur in the organic shrinking agent may be larger than 3000 μmol / g, preferably 3500 μmol / g or more, more preferably 4000 μmol / g or more, and particularly preferably 6000 μmol / g or more. On the other hand, there is a limit to increasing the content of elemental sulfur in the organic shrinking agent. Therefore, the content of the elemental sulfur in the organic shrinking agent is preferably 10,000 μmol / g or less, more preferably 9000 μmol / g or less, and still more preferably 8000 μmol / g or less. In addition, the content of the elemental sulfur in the organic shrinking agent being X μmol / g means that the content of the elemental sulfur contained in 1 g of the organic shrinking agent is X μmol.

As the fibrous material, at least one selected from the group consisting of glass fiber, polymer fiber, carbon fiber and pulp fiber is preferable, and polymer fiber is particularly preferable in terms of stability. The polymer constituting the polymer fiber is not particularly limited as long as it has acid resistance, and examples thereof include polyolefin fiber, polyester fiber, and acrylic fiber. Among these, acrylic fibers are preferable. Examples of the acrylic fiber material include polyacrylonitrile, polyacrylic acid, polymethacrylic acid, polyacrylic acid ester (for example, polymethyl acrylate), polymethacrylic acid ester (for example, polymethyl methacrylate), and the like.

The average fiber diameter of the fibrous material is preferably 1 μm or more and 50 μm or less, for example, and the average fiber length is preferably 1 mm or more and 10 mm or less, for example. These average values can be obtained from an enlarged photograph of selected fibers by arbitrarily selecting 10 or more fibers, as will be described later.

From the viewpoint of sufficiently obtaining the effect of suppressing the voltage drop while securing the capacity, the content (mass ratio Cm) of the fibrous substance in the negative electrode material is 0.03% by mass or more and 0.3% by mass or less. preferable. Further, the volume ratio Cv of the fibrous substance in the negative electrode material is preferably 0.03% by volume or more and 0.3% by volume or less. Here, content of the fibrous substance contained in negative electrode material is content in the negative electrode material of the lead acid battery of an already formed fully charged state.

Even when the negative electrode material contains a fibrous substance and an organic shrinking agent, it is difficult to suppress a voltage drop if the content of sulfur element in the organic shrinking agent is 3000 μmol / g or less. This is presumably because the stress generated between the active material particles due to charge / discharge cannot be sufficiently suppressed when the content of the elemental sulfur in the organic shrinking agent is 3000 μmol / g or less. Even when the content of elemental sulfur in the organic shrinking agent is greater than 3000 μmol / g, it is difficult to suppress a voltage drop without a fibrous substance. That is, the voltage drop is suppressed by the synergistic action of the organic shrinkage agent having a sulfur element content of greater than 3000 μmol / g and the fibrous material.

The effect of suppressing the voltage drop during high rate discharge becomes significant when the thickness of the negative electrode plate is 2 mm or more. A negative electrode plate having a thickness of 2 mm or more is prone to cracks due to the occurrence of stress due to a large amount of deformation due to contraction of the active material. In such a negative electrode plate, for example, the effect of securing a conductive path by a fibrous material and the effect of suppressing the stress by the organic shrinkage agent are likely to be manifested. Therefore, the effect of suppressing the voltage drop is also likely to be manifested. The thickness of the negative electrode plate may be 3 mm or more, or 4 mm or more. Although the upper limit of the thickness of a negative electrode plate is not specifically limited, 8 mm or less is preferable.

The lead acid battery may be a liquid (vented) lead acid battery or a control valve (sealed) lead acid battery. However, the negative electrode plate having a thickness of 2 mm or more is suitable for a larger lead acid battery than a lead acid battery for automobiles. Examples of large lead-acid batteries include lead-acid batteries for stationary uninterruptible power supplies and lead-acid batteries for industrial vehicles such as forklifts.

Hereinafter, although the lead storage battery which concerns on embodiment of this invention is demonstrated for every structural requirement, this invention is not limited to the following embodiment.
(Negative electrode plate)
A negative electrode plate of a lead storage battery includes a negative electrode current collector and a negative electrode material. The negative electrode material is held on the negative electrode current collector. The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead or lead alloy sheet. Examples of the processing method include expanding processing and punching.

The lead alloy used for the negative electrode current collector may be any of a Pb—Sb alloy, a Pb—Ca alloy, and a Pb—Ca—Sn alloy. These lead or lead alloy may further contain at least one element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like as an additive element. The negative electrode current collector may have lead alloy layers having different compositions, and a plurality of lead alloy layers may be provided.

The negative electrode material includes a negative electrode active material (lead or lead sulfate) that develops capacity by an oxidation-reduction reaction, an organic shrinkage agent having a sulfur element content of greater than 3000 μmol / g, and a fibrous material. The negative electrode material may further contain a carbonaceous material such as carbon black, barium sulfate, and the like, and may contain other additives as necessary.

The negative electrode plate can be formed by filling a negative electrode current collector with a negative electrode paste, aging and drying to produce an unformed negative electrode plate, and then forming an unformed negative electrode plate. Aging and drying of the unformed negative electrode plate is preferably performed at a temperature higher than room temperature and high humidity. What is necessary is just to prepare a negative electrode paste by adding water and a sulfuric acid to lead powder, an organic shrinking agent, and various additives, and knead | mixing them.

The chemical conversion can be performed by charging the electrode plate group in a state where the electrode plate group including the unformed negative electrode plate is immersed in an electrolytic solution containing sulfuric acid in the battery case of the lead storage battery. However, the chemical conversion may be performed before the assembly of the lead storage battery or the electrode plate group. Sponge-like lead is generated by chemical conversion.

(Positive electrode plate)
The positive electrode plate of the lead storage battery can be classified into a paste type, a clad type and the like.
The paste type positive electrode plate includes a positive electrode current collector and a positive electrode material. The positive electrode material is held by the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and can be formed by casting lead or a lead alloy or processing a lead or lead alloy sheet.
The clad positive electrode includes a plurality of porous tubes, a core metal inserted into each tube, a positive electrode material filled in the tube in which the core metal is inserted, and a joint that connects the plurality of tubes. It has.

As the lead alloy used for the positive electrode current collector, a Pb—Ca alloy and a Pb—Ca—Sn alloy are preferable in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have lead alloy layers having different compositions, and a plurality of lead alloy layers may be provided. It is preferable to use a Pb—Sb alloy for the core metal.

The positive electrode material includes a positive electrode active material (lead oxide or lead sulfate) that develops capacity by an oxidation-reduction reaction. The positive electrode material may contain additives such as tin sulfate and red lead as necessary.

An unformed paste-type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste, aging and drying in accordance with the case of the negative electrode plate. The positive electrode paste may be prepared by kneading lead powder, additives, water, and sulfuric acid. Thereafter, an unformed positive electrode plate is formed. The clad positive electrode plate is formed by filling a porous tube into which a core metal is inserted with lead powder or slurry-like lead powder, and joining a plurality of tubes together.

(Electrolyte)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled as necessary. The degree of gelation is not particularly limited. A gel electrolyte may be used from a fluid sol, or a gel electrolyte without fluid may be used.

(Separator)
As the separator, a microporous film, a nonwoven fabric, an AGM (Absorbed glass mat), or the like is used. A microporous membrane is usually used for a liquid lead-acid battery. On the other hand, an AGM having a retainer function for holding an electrolytic solution is usually used for a control valve type lead-acid battery.

The microporous membrane can be obtained, for example, by extruding a composition containing ultrahigh molecular weight polyethylene, silica powder and oil into a sheet and then extracting the oil to form pores. AGM is a nonwoven fabric mainly composed of glass fibers having an average fiber diameter of 1 μm or less, for example.

Next, a method for analyzing each physical property will be described.
(1) Density of negative electrode material 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 conversion is fully charged and 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 unground measurement sample. After putting the sample into the measurement container and evacuating it, 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 bulk density of the negative electrode material is obtained. The volume obtained by subtracting the injection volume of mercury from the volume of the measurement container is defined as the bulk volume.

In order to fully charge the battery, in the case of a liquid lead-acid battery, constant current charging is performed in a water bath at 25 ° C. until it reaches 2.5 V / cell at a 5-hour rate current, and then for another 5 hours. Charge at a constant current for 2 hours. In the case of a control valve type lead-acid battery, a constant current and constant voltage charge of 2.23 V / cell is performed at 25 ° C. in an air tank at a 5-hour rate current, and the charge current during constant voltage charge is 1 mCA or less. When it is time to finish charging.
The 5-hour rate current in this specification is a current value for discharging the battery nominal capacity in 5 hours. For example, if the battery has a nominal capacity of 30 Ah, the 5-hour rate current is 6 A. 1CA is a current value (A) having the same numerical value as the nominal capacity (Ah) of the battery. For example, if the battery has a nominal capacity of 30 Ah, 1CA is 30 A, and 1 mCA is 30 mA.

(2) Analysis of Organic Shrinkage Agent First, a lead-acid battery fully charged after chemical conversion is disassembled, the negative electrode plate is taken out, sulfuric acid is removed by washing with water, and dried. Next, a negative electrode material (initial sample) is collected from the dried negative electrode plate, and the initial sample is analyzed by the following method.

(2-1) Qualitative characteristics of organic shrinkage agent in negative electrode material The initial sample is immersed in a 1 mol / L NaOH aqueous solution to extract the organic shrinkage agent. Next, insoluble components are removed by filtration from the extracted aqueous NaOH solution containing the organic shrinking agent, and the obtained filtrate is desalted by dialysis, then concentrated and dried. Desalting may be performed by placing the filtrate in a dialysis tube and immersing it in distilled water. Thereby, a powder sample of the organic shrinking agent is obtained.

Obtained from the infrared spectroscopic spectrum measured using a powder sample of the organic shrinkage agent thus obtained, and the UV-visible absorption spectrum and NMR spectrum measured with an ultraviolet-visible absorptiometer after the powder sample was dissolved in an appropriate solvent. Information is used in combination to identify the organic pre-shrinking agent species.

(2-2) Content of Organic Shrinking Agent in Negative Electrode Material As in the case of (2-1) above, after obtaining a filtrate of an NaOH aqueous solution containing an organic shrinking agent, the ultraviolet-visible absorption spectrum of the filtrate is measured. Using the spectrum intensity and a calibration curve prepared in advance, the content of the organic shrinking agent in the negative electrode material can be quantified.

When obtaining a lead-acid battery with an unknown content of the organic shrinking agent and measuring the content of the organic shrinking agent, the structural formula of the organic shrinking agent cannot be specified precisely. If it cannot be used, use an organic shrunk agent that is extracted from the negative electrode of the battery and an organic shrunk agent that has a similar shape such as an ultraviolet-visible absorption spectrum, an infrared spectroscopic spectrum, and an NMR spectrum. By creating a calibration curve, the content of the organic anti-shrinking agent is measured using an ultraviolet-visible absorption spectrum. *

(2-3) Content of elemental sulfur in organic shrinkage agent In the same manner as in (2-1) above, after obtaining a powder sample of an organic shrinkage agent, 0.1 g of the organic shrinkage agent was obtained by an oxygen combustion flask method. The elemental sulfur is converted to sulfuric acid. At this time, an eluate in which sulfate ions are dissolved in the adsorbent is obtained by burning the powder sample in the flask containing the adsorbent. Next, the eluate is titrated with barium perchlorate using thorin as an indicator to determine the content (C1) of elemental sulfur in 0.1 g of the organic shrinking agent. Next, C1 is multiplied by 10, and the content (μmol / g) of elemental sulfur in the organic shrinkage agent per gram is calculated.

(3) Analysis of fibrous substance 10 g of negative electrode material that had been washed and dried was pulverized and dissolved under heating with 50 mL of 1: 2 nitric acid (concentrated nitric acid and water mixed in a volume ratio of 1: 2). Add a large excess of supersaturated aqueous ammonium acetate solution and stir to completely dissolve the lead sulfate. The solution is filtered through a glass filter and the fibrous material is collected by filtration. After the fibrous substance is washed and dried, its mass is measured, and the content of the fibrous substance is calculated. The average fiber length and average fiber diameter are determined by observing the obtained fibrous substance with an optical microscope.

FIG. 1 is a perspective view schematically showing an example in which a lid of a lead storage battery according to an embodiment of the present invention is removed. 2A is a front view of the lead storage battery of FIG. 1, and FIG. 2B is a cross-sectional view taken along line II-II of FIG. 2A.
The lead storage battery 1 includes a battery case 10 that houses an electrode plate group 11 and an electrolyte solution 12. The electrode plate group 11 is configured by laminating a plurality of negative plates 2 and positive plates 3 with a separator 4 interposed therebetween. Here, the negative electrode plate 2 is shown as being wrapped by a separator 4 folded in two, but the form of the separator is not particularly limited.

A current collecting ear portion (not shown) protruding upward is provided on each of the plurality of negative electrode plates 2. A current collecting ear (not shown) protruding upward is also provided on each upper portion of the plurality of positive electrode plates 3. And the ear | edge parts of the negative electrode plate 2 are connected and integrated by the strap 5a for negative electrodes. Similarly, the ears of the positive electrode plate 3 are connected and integrated by the positive strap 5b. The lower end of the negative pole 6a is fixed to the upper part of the negative strap 5a, and the lower end of the positive pole 6b is fixed to the upper part of the positive strap 5b.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
(1) Production of Negative Electrode Plate Lead powder, water, dilute sulfuric acid, barium sulfate, carbon black, a predetermined amount of organic shrinkage agent, and a predetermined amount of fibrous material were mixed to obtain a negative electrode paste. The negative electrode paste was filled in a mesh part of a cast lattice made of a Pb—Sb alloy and aged and dried to obtain an unformed negative electrode plate. The thickness of the unformed negative electrode plate was designed such that the thickness of the negative electrode plate of the lead storage battery fully charged after the formation was 3 mm. Further, the negative electrode paste was blended so that the negative electrode material of the lead-acid battery fully charged after chemical conversion contained 0.1% by mass of BaSO ₄ and 0.2% by mass of carbon black.

The organic shrunk agent was blended in the negative electrode paste so that the content of the organic shrunk agent in the negative electrode material of the lead-acid battery fully charged after chemical conversion was 0.1% by mass. Moreover, the amount of water and dilute sulfuric acid added to the negative electrode paste was adjusted so that the density of the negative electrode material of the lead-acid battery fully charged after the formation was 3.0 g / cm ³ .
For the density measuring device of the negative electrode material, Shimadzu Corporation, an automatic porosimeter, and Autopore IV95505 were used and measured using the method described above.

As the organic shrunk agent, a condensate (synthetic shrunk agent) of bisphenol A introduced with a sulfonic acid group by formaldehyde was used. Here, the amount of the sulfonic acid group to be introduced was controlled so that the content of the elemental sulfur in the organic shrinking agent was 5000 μmol / g.

An acrylic fiber was used as the fibrous material. The fibrous material was blended in the negative electrode paste so that the content of the fibrous material in the fully formed negative electrode material in the fully formed state was 0.1% by mass. The average fiber length of the acrylic fiber was 3 mm. In addition, the shape of the fibrous substance mix | blended with the negative electrode paste is hold | maintained also in the already formed negative electrode material.

(2) Preparation of positive electrode plate A positive electrode paste containing lead powder was prepared, and a plurality of glass fiber tubes into which a plurality of Pb-Sb alloy cores were respectively inserted were filled with the positive electrode paste. The tube opening was closed at the joint, and an unformed positive electrode plate was assembled.

(3) Production of lead-acid battery An unformed negative electrode plate is accommodated in a bag-like polyethylene microporous membrane (separator), and an electrode plate group consisting of four unformed negative electrode plates and three unformed positive electrode plates Formed.

The electrode plate group was accommodated in a polypropylene battery case together with the electrolyte, and chemical conversion was performed in the battery case to obtain a liquid lead-acid battery with 2 V and a rated 5-hour rate capacity of 165 Ah.

<< Comparative Example 1 >>
An electrode plate group was prepared in the same manner as in Example 1 except that the fibrous material was not included in the negative electrode material, and a lead storage battery was assembled.

[Evaluation 1]
Regarding the lead acid batteries of Example 1 and Comparative Example 1, a charge / discharge cycle of 41.3 A × 3 hours of discharge and 29.7 A × 5 hours of charge was repeated in a 30 ° C. water tank, every 200 cycles. , High-rate discharge for 100 seconds at 165A. At this time, the difference between the discharge voltage at 100 seconds and the open circuit voltage (OCV) was determined as a voltage drop.
Table 1 and FIG. 3 show the relationship between the number of charge / discharge cycles and the voltage drop.

In FIG. 3, in the lead storage battery of Comparative Example 1, the voltage drop starts to increase after 200 cycles, and at 1000 cycles, the voltage drop is nearly 50% larger than the initial value. On the other hand, in the lead storage battery of Example 1, the voltage drop hardly increases even at the 1000th cycle. From this, it can be understood that the fibrous material plays an important role in suppressing the voltage drop.

Example 2
The content of elemental sulfur in the organic shrinking agent is set to 4000 μmol / g, and the density of the negative electrode material of the lead-acid battery fully charged after chemical conversion is changed in the range of 2.3 g / cm ³ to 4.5 g / cm ^3. In the same manner as in Example 1, a plurality of types of electrode plate groups were prepared, and lead storage batteries 4000A to 4000G shown in Table 2 were assembled. Lead storage batteries 4000A and 4000G are reference examples.

<< Comparative Example 2 >>
The density of the negative electrode material of the lead-acid battery fully charged after chemical conversion is 2.3 g / cm ³ to 4.5 g / cm ³ , except that the fibrous material is not included in the negative electrode material. A plurality of types of electrode plates having a negative electrode plate were prepared, and lead-acid batteries 4000a to 4000g shown in Table 3 were assembled.

[Evaluation 2]
For the lead storage batteries of Example 2 and Comparative Example 2, the same charge / discharge cycle as in Evaluation 1 was repeated, and the voltage drop during high-rate discharge after 600 cycles had been determined.
Table 4 and FIG. 4 show the relationship between the density of the negative electrode material and the voltage drop at the 600th cycle.

In FIG. 4, in the lead storage battery of Example 2, the voltage drop is kept low in all cases except for the reference example in which the negative electrode density is less than 2.5 g / cm ³ . On the other hand, in the lead storage battery of Comparative Example 2, the voltage drop is large except for the case where the negative electrode density exceeds 4.0 g / cm ³ . From this, it can be understood that the negative electrode density should be 2.5 g / cm ³ or more in order to obtain the effect of suppressing the voltage drop. In addition, when the negative electrode density exceeds 4.0 g / cm ³ , it can be understood that there is no need to dare to use a fibrous substance because a voltage drop phenomenon hardly occurs in the first place.

<< Comparative Example 3 >>
The density of the negative electrode material of the lead-acid battery fully charged after chemical conversion is 2.3 g / cm ³ to 4. 4 except that the content of sulfur element in the synthetic organic shrinking agent is changed to 3000 μmol / g. A plurality of types of electrode plate groups of 5 g / cm ³ were prepared, and lead-acid batteries 3000A to 3000G shown in Table 5 were assembled.

Example 3
The density of the negative electrode material of the lead storage battery fully charged after chemical conversion is 2.3 g / cm ³ to 4. 4 except that the content of elemental sulfur in the synthetic organic shrinking agent is changed to 5000 μmol / g. A plurality of types of electrode plate groups of 5 g / cm ³ were prepared, and lead storage batteries 5000A to 5000G shown in Table 6 were assembled. Lead storage batteries 5000A and 5000G are reference examples.

Example 4
The density of the negative electrode material of the lead-acid battery fully charged after chemical conversion is 2.3 g / cm ³ to 4. 4 except that the content of the elemental sulfur in the synthetic organic shrinking agent is changed to 6000 μmol / g. A plurality of types of electrode plate groups of 5 g / cm ³ were prepared, and lead storage batteries 6000A to 6000G shown in Table 7 were assembled. Lead storage batteries 6000A and 6000G are reference examples.

Example 5
The density of the negative electrode material of the lead-acid battery fully charged after chemical conversion is 2.3 g / cm ³ to 4. 4 except that the content of sulfur element in the synthetic organic shrinking agent is changed to 8000 μmol / g. A plurality of types of electrode plate groups of 5 g / cm ³ were produced, and lead-acid batteries 8000A to 8000G shown in Table 8 were assembled. Lead storage batteries 8000A and 8000G are reference examples.

[Evaluation 3]
For the lead storage batteries of Examples 2, 3 to 5 and Comparative Example 3, the same charge / discharge cycle as in Evaluation 1 was repeated, and the voltage drop during high rate discharge after 600 cycles was determined.
Table 9 and FIG. 5 show the relationship between the density of the negative electrode material and the voltage drop during high-rate discharge after elapse of 600 cycles when the content of elemental sulfur in the organic shrinking agent is changed.

In FIG. 5, in the lead storage battery of Comparative Example 3, the voltage drop is large over the entire range of the density of the negative electrode material from 2.3 g / cm ³ to 4.5 g / cm ³ . On the other hand, in the lead storage batteries of Examples 3 to 5, the voltage drop is suppressed to a low level except for the reference example in which the negative electrode density is less than 2.5 g / cm ³ . From this, it is important in suppressing the voltage drop that the content of the elemental sulfur in the organic shrinkage agent is greater than 3000 μmol / g. In the organic shrinkage agent having the sulfur element content of 3000 μmol / g, the fibrous material It can be understood that the voltage drop cannot be suppressed even by using.

<< Comparative Example 4 >>
The density of the elemental sulfur in the synthetic organic shrinking agent is changed to 3000 μmol / g, 4000 μmol / g, 6000 μmol / g or 8000 μmol / g, and the density of the negative electrode material of the lead-acid battery fully charged after the formation is 3.2 g / cm ^3. In the same manner as in Comparative Example 1, except that the electrode plate group including the negative electrode plate not containing the fibrous material was prepared, the lead storage batteries 3000d, 4000d, 5000d, 6000d, and 8000d shown in Table 10 were assembled. It was. In Table 10, the lead storage battery 5000d is the same as one of the lead storage batteries of Comparative Example 1, and the lead storage battery 4000d is the same as one of the lead storage batteries of Comparative Example 2.

<< Comparative Example 5 >>
The synthetic organic pre-shrinking agent was changed to lignin (the content of sulfur element was 600 μmol / g), and the density of the negative electrode material of the lead-acid battery fully charged after chemical conversion was 3.2 g / cm ³ , Similarly to Example 1, an electrode plate group including a negative electrode plate containing a fibrous substance was produced, and a lead storage battery 600D was assembled.

<< Comparative Example 6 >>
The synthetic organic pre-shrinking agent was changed to lignin (the content of sulfur element was 600 μmol / g), and the density of the negative electrode material of the lead-acid battery fully charged after chemical conversion was 3.2 g / cm ³ , Similar to Comparative Example 1, an electrode plate group including a negative electrode plate not containing a fibrous material was produced, and a lead storage battery 600d was assembled.

[Evaluation 4]
For the lead acid batteries of Comparative Examples 4 to 6, the same charge / discharge cycle as in Evaluation 1 was repeated, and the voltage drop during high rate discharge after 600 cycles had been determined. Table 10 shows the voltage drop of the lead acid batteries of Comparative Examples 1 and 4 to 6.

From Table 10, it can be understood that the voltage drop when the negative electrode material does not contain a fibrous substance does not occur when lignin is used, but is a phenomenon peculiar when a synthetic organic shrinking agent is used. That is, when lignin is used instead of the synthetic organic anti-shrink agent, the voltage drop is small regardless of the presence or absence of the fibrous material.

Also, regarding the lead storage batteries of Comparative Example 4 and Comparative Example 6, the discharge capacity obtained at the 800th cycle of the charge / discharge cycle is shown in Table 11 as a relative value. Table 11 also shows the discharge capacity at the 800th cycle of the lead storage battery 5000D of Example 3.

From Table 11, it can be seen that when lignin is used, the capacity decreases when the charge / discharge cycle is repeated at room temperature. Moreover, it can be understood that such a decrease in capacity is suppressed by using a synthetic organic shrinking agent instead of lignin.

Example 6
A plurality of kinds of electrode plate groups were prepared in the same manner as in Example 1 except that the content of elemental sulfur in the organic shrinking agent was 4000 μmol / g and the thickness of the negative electrode plate was changed in the range of 2 mm to 6 mm. Then, lead storage batteries 4000X (2) to 4000X (6) shown in Table 12 were assembled. Moreover, the rated capacity was changed according to the thickness of the negative electrode plate.

[Evaluation 5]
For the lead storage battery of Example 6, the same charge / discharge cycle as in Evaluation 1 was repeated, and the voltage drop during high-rate discharge after 600 cycles had been determined. Table 12 shows the voltage drop of the lead storage battery of Example 6 as a percentage (%) with respect to the initial value.

From Table 12, it can be understood that the effect of suppressing the voltage drop can be obtained even when the thickness of the negative electrode plate is changed.

The present invention is applicable to a liquid type lead storage battery and a control valve type lead storage battery, and is suitably used as a power source for an automobile, an industrial vehicle (forklift, etc.), or an uninterruptible power source.

1: lead acid battery 2: negative electrode plate 3: positive electrode plate 4: separator 5a: strap for negative electrode 5b: strap for positive electrode 6a: negative electrode column 6b: positive electrode column 10: battery case 11: electrode plate group 12: electrolyte

Claims

A negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the positive electrode plate, and an electrolyte solution,
The negative electrode plate includes a negative electrode current collector and a negative electrode material,
The negative electrode material includes an organic shrinkage agent containing sulfur element, and a fibrous substance,
The negative electrode material has a density of 2.5 g / cm 3 or more and 4.0 g / cm 3 or less,
The lead acid battery whose content of the said sulfur element in the said organic shrink-proof agent is larger than 3000 micromol / g.
The lead acid battery according to claim 1, wherein the density of the negative electrode material is 2.7 g / cm 3 or more and 4.0 g / cm 3 or less.
The lead acid battery according to claim 1 or 2, wherein the thickness of the negative electrode plate is 2 mm or more.
The lead acid battery according to any one of claims 1 to 3, wherein the fibrous substance is a polymer fiber.
The content of the sulfur element in the organic shrinkage agent is greater than 3500 μmol / g,
The lead acid battery according to any one of claims 1 to 4.
The content of the elemental sulfur in the organic shrinking agent is greater than 4000 μmol / g,
The lead acid battery according to any one of claims 1 to 4.
The content of the sulfur element in the organic shrinkage agent is greater than 6000 μmol / g,
The lead acid battery according to any one of claims 1 to 4.
The content of the sulfur element in the organic shrinking agent is 10000 μmol / g or less,
The lead acid battery according to any one of claims 1 to 7.
The content of the sulfur element in the organic shrinking agent is 8000 μmol / g or less.
The lead acid battery according to any one of claims 1 to 7.
The lead-acid battery according to any one of claims 1 to 9, wherein the thickness of the negative electrode plate is 3 mm or more.
The lead acid battery according to any one of claims 1 to 9, wherein the thickness of the negative electrode plate is 4 mm or more.
The lead acid battery according to any one of claims 1 to 9, wherein a thickness of the negative electrode plate is 8 mm or less.