JP2022085745A - Lead acid battery - Google Patents

Abstract

To provide a lead acid battery with high rate discharge performance and charge acceptance performance.SOLUTION: A lead acid battery disclosed herein includes a negative electrode containing negative electrode material, and a positive electrode. The negative electrode material contains an organic shrinkage proofing agent and barium sulfate. The organic shrinkage proofing agent is a condensate containing a bisphenol unit. The surface area of barium sulfate is 0.04 m2 or more per 1 g of the negative electrode material.SELECTED DRAWING: None

Description

The present invention relates to a lead storage battery.

Lead-acid batteries are used in various applications such as in-vehicle use and industrial use. Lead-acid batteries usually include a negative electrode plate, a positive electrode plate, a separator (or mat), an electrolytic solution, and the like. Each electrode plate comprises a current collector and an electrode material. From the viewpoint of imparting various functions, various additives are added to the electrode material.

Patent Document 1 (Japanese Unexamined Patent Publication No. 2012-043594) states that "the negative electrode active material contains barium sulfate, lignin, a salt of a naphthalene sulfonic acid formaldehyde condensate, and a bisphenol / sulfonic acid / formaldehyde condensate as essential components. Negative plate for lead-acid battery. ”(Claim 1) is disclosed.

Patent Document 2 (Japanese Unexamined Patent Publication No. 10-040906) states that "a micronizer powder made of MSO ₄ (for example, BaSO ₄ ) which has the same crystal form as the discharge product of the negative electrode active material and can be a crystal nucleus is a negative electrode. In the negative electrode plate for a closed lead-acid battery contained in the active material layer, a sphere calculated as the micronizer powder and the median diameter obtained by the laser diffraction type grain soil distribution measurement method as the micronizer powder. The sealing is characterized by using a powder having a ratio S2 / S1 of the value S1 obtained by multiplying the surface area of the above and the number of powders to the total surface area S2 of the entire micronizing agent powder obtained by the BET method of 2.2 or less. Negative electrode plate for lead-acid batteries. "

Patent Document 3 (International Publication No. 2018/10069) is a lead storage battery including a positive electrode, a negative electrode, a separator arranged between the positive electrode and the negative electrode, and an electrolytic solution, wherein the negative electrode is a lead storage battery. A negative electrode material containing a chemical conversion product of a mixture containing a raw material for a negative electrode active material and particles containing barium (such as barium sulfate), and the average primary particle size of the particles before the chemical conversion treatment is 0.10 μm. The following is disclosed, which is a lead storage battery in which the electrolytic solution contains sodium ions. "

Japanese Unexamined Patent Publication No. 2012-043594 Japanese Unexamined Patent Publication No. 10-040906 International Publication No. 2018/100639

Lead-acid batteries are required to have various characteristics improved. For example, lead-acid batteries are required to have high high rate discharge performance (particularly high rate discharge performance at low temperature) and high charge acceptance performance. It is difficult to achieve both of these at a high level.

One aspect of the present invention relates to a lead storage battery. The lead-acid battery is a lead-acid battery containing a negative electrode including a negative electrode material and a positive electrode. The negative electrode material contains an organic shrinkage proofing agent and barium sulfate, and the organic shrinkage proofing agent contains a bisphenol unit. The surface area of the barium sulfate is 0.04 m ² or more per 1 g of the negative electrode material.

According to the present invention, a lead storage battery having both high rate discharge performance and charge acceptance performance can be obtained.

It is an exploded perspective view which cut out a part which shows the appearance and the internal structure of the lead storage battery which concerns on one aspect of this invention. It is a graph which shows an example of the relationship between the surface area (Z) of barium sulfate particles and low temperature high rate discharge performance. It is a graph which shows an example of the relationship between the surface area (Z) of barium sulfate particles, and charge acceptance performance.

Hereinafter, embodiments of the present invention will be described with reference to examples, but the present invention is not limited to the examples described below. In the following description, specific numerical values and materials may be exemplified, but other numerical values and materials may be applied as long as the effects of the present invention can be obtained. In this specification, when the term "numerical value A to numerical value B" is used, the range includes the numerical value A and the numerical value B.

(Lead-acid battery)
The lead-acid battery according to the present embodiment includes a negative electrode including a negative electrode electrode material and a positive electrode. The negative electrode material contains an organic shrinkage proofing agent and barium sulfate. The organic shrink proofing agent is a condensate containing a bisphenol unit. The organic shrinkage proofing agent may be referred to as "organic shrinkage proofing agent (B)" below. The surface area of barium sulfate is 0.04 m ² or more per 1 g of the negative electrode material. Hereinafter, the surface area of barium sulfate per 1 g of the negative electrode material may be referred to as “surface area (Z)”. In a typical example of the lead storage battery according to the present embodiment, barium sulfate in the negative electrode electrode material can be regarded as existing in the state of particles, so that barium sulfate can be read as barium sulfate particles.

It is known that the characteristics of lead-acid batteries are improved by adding barium sulfate to the negative electrode material. The added barium sulfate acts as a nucleus of lead sulfate produced during discharge, resulting in the production of fine lead sulfate. Therefore, lead sulfate is likely to be generated during discharge. Further, since the produced lead sulfate is fine, the lead sulfate can be easily dissolved during charging. For these reasons, it is considered that the characteristics of lead-acid batteries are improved. However, as a result of the study, the inventors of the present application have newly found that the effect of adding barium sulfate differs depending on the type of the organic shrinkage proofing agent added to the negative electrode electrode material. As a result of further studies, the inventors of the present application have found that there is a specific relationship between the type of organic shrinkage proofing agent and the conditions for adding barium sulfate and the characteristics of lead-acid batteries. The present invention is an invention based on this new finding.

According to the configuration of the present embodiment, a lead storage battery having high high rate discharge performance and high charge acceptance performance can be obtained. The reason why this effect is obtained is not clear at present, but it can be considered as follows. When the surface of barium sulfate is coated with an organic shrink-proofing agent, the effect of adding barium sulfate is reduced. From various studies, it was found that the area where the organic shrink-proofing agent (B) covers the negative electrode active material or the additive may be larger than the area where the same amount of the lignin compound covers the negative electrode active material or the additive. rice field. Therefore, when the organic shrinkage proofing agent (B) is used as the organic shrinkage proofing agent, it is considered necessary to add barium sulfate to the negative electrode electrode material so as to have a surface area (Z) of a predetermined value or more.

Bisphenol is a compound having two hydroxyphenyl groups. The bisphenol unit is a unit derived from bisphenol among the units constituting the condensate. The condensate is obtained by condensing a plurality of compounds including bisphenol. Hereinafter, bisphenol may be referred to as a "bisphenol compound".

The surface area (Z) of barium sulfate per 1 g of the negative electrode material is 0.04 m ² or more, and may be 0.05 m ² or more. The upper limit of the surface area (Z) is not particularly limited, and may be 0.15 m ² or less, 0.09 m ² or less, or 0.07 m ² or less. By setting the surface area to 0.15 m ² or less, it is possible to suppress an adverse effect (for example, a decrease in the binding property between lead particles (active materials)) due to an excessively large content of barium sulfate. These lower and upper limits can be combined arbitrarily as long as there is no contradiction. For example, the surface area (Z) is in the range of 0.04 m ² to 0.15 m ² , 0.04 m ² to 0.09 m ² , 0.04 m ² to 0.07 m ² , 0.05 m ² to. It may be in the range of 0.15 m ² , the range of 0.05 m ² to 0.09 m ² , and the range of 0.05 m ² to 0.07 m ² .

The surface area (Z) of barium sulfate per 1 g of the negative electrode electrode material can be adjusted, for example, by changing the amount of barium sulfate added and at least one of the particle size of barium sulfate. For example, the surface area (Z) can be increased by increasing the amount of barium sulfate added. Further, when the amount of barium sulfate added is the same, the smaller the particle size of barium sulfate, the larger the surface area (Z).

The average particle size of barium sulfate may be 0.5 μm or more and 1.0 μm or less. The average particle size of barium sulfate may be 0.5 μm or more and 0.8 μm or less, or 0.8 μm or more and 1.0 μm or less. By setting the average particle size of barium sulfate to 0.5 μm or more, it is possible to suppress the outflow of barium sulfate. By setting the average particle size of barium sulfate to 1.0 μm or less, the surface area (Z) of barium sulfate can be increased with a small amount of addition.

The average particle size of barium sulfate in the negative electrode electrode material can be adjusted, for example, by changing the particle size of the barium sulfate particles added when the negative electrode plate is manufactured. Since barium sulfate particles having various particle sizes are commercially available, the particle size of the barium sulfate particles to be added can be easily controlled by using them.

The content of barium sulfate in the negative electrode electrode material may be 0.9% by mass or more. By setting the content to 0.9% by mass or more, both high rate discharge performance and charge acceptance performance can be achieved at a particularly high level. The content may be 0.5% by mass or more, 0.9% by mass or more, 1.2% by mass or more, 1.5% by mass or more, or 1.8% by mass or more. The upper limit of the content is not particularly limited, but may be, for example, 3.2% by mass or less, 2.8% by mass or less, 2.4% by mass or less, or 2.1% by mass or less. These lower and upper limits can be combined arbitrarily as long as there is no contradiction. For example, the content is in the range of 0.5 to 3.2% by mass, the range of 0.9 to 2.8% by mass, the range of 1.2 to 2.8% by mass, and 1.5 to 2.8. It may be in the range of% by mass, 0.9 to 2.4% by mass, or 0.9 to 2.1% by mass.

The surface area (Z) of barium sulfate, the average particle size, and the content of barium sulfate in the negative electrode material are measured by the methods described below. That is, they are values measured by the methods described below.

Examples of bisphenol units include bisphenol A units, bisphenol S units, bisphenol F units and the like. The organic shrinkage proofing agent (B) may be a condensate containing at least one selected from the group consisting of a bisphenol A unit, a bisphenol S unit, and a bisphenol F unit. For example, the organic shrinkage proofing agent (B) may contain a bisphenol A unit, a bisphenol S unit, a bisphenol F unit, or two or three units selected from them. It may be included. For example, the organic shrinkage proofing agent (B) may be a condensate containing a bisphenol S unit and a bisphenol A unit. The bisphenol A unit, bisphenol S unit, and bisphenol F unit are units derived from bisphenol A, bisphenol S, and bisphenol F, respectively.

The organic shrinkage proofing agent (B) may contain other units in addition to the bisphenol unit. Examples of other units include phenol sulfonic acid units and the like.

The organic shrinkage proofing agent (B) can be obtained, for example, by condensing the compound from which the above unit is derived with another compound. Examples of other compounds include aldehyde compounds (eg formaldehyde), sodium sulfite and the like. As the organic shrinkage proofing agent (B), a commercially available product may be used, or a commercially available synthetic agent (B) may be synthesized based on a known synthetic method. Specific examples of the organic shrinkage proofing agent (B) will be described later.

The organic shrinkage proofing agent (B) may be synthesized by reacting a bisphenol with an aldehyde compound. Here, the reaction between the bisphenol and the aldehyde compound is carried out in the presence of a sulfite, or the bisphenol containing a sulfur element (for example, bisphenol S) is used to obtain an organic shrinkage proofing agent (B) containing a sulfur element. It is possible. The bisphenol to be condensed to obtain the organic shrinkage proofing agent (B) may be one kind or two or more kinds. The aldehyde compound may be an aldehyde (for example, formaldehyde), a condensate (or a polymer) of an aldehyde, or the like. Examples of the aldehyde condensate (or polymer) include paraformaldehyde, trioxane, tetraoxymethylene and the like. As the aldehyde compound, one kind may be used alone, or two or more kinds may be used in combination.

Bisphenol may have a sulfur-containing group. That is, the organic shrinkage proofing agent (B) may contain a sulfur element. The sulfur-containing group may be directly bonded to the aromatic ring contained in bisphenol. Examples of sulfur-containing groups include sulfonic acid groups and sulfonyl groups. The sulfonic acid group may be present in acid form or may be present in salt form such as Na salt.

The content of the organic shrinkage barrier (B) contained in the negative electrode electrode material may be 0.01% by mass or more. According to this configuration, the low temperature and high rate discharge performance can be particularly enhanced. The content may be 0.05% by mass or more, 0.1% by mass or more, or 0.2% by mass or more. The content may be 1.0% by mass or less, 0.6% by mass or less, 0.4% by mass or less, or 0.2% by mass or less. As long as there is no contradiction between these lower and upper limits, they can be combined arbitrarily. For example, the content is in the range of 0.01 to 1.0% by mass, in the range of 0.05 to 0.4% by mass, in the range of 0.05 to 0.2% by mass, or 0.1 to 0%. It may be in the range of 2% by mass.

The negative electrode electrode material may or may not contain an organic shrinkage proofing agent other than the organic shrinkage proofing agent (B). Examples of such other organic shrink proofing agents will be described later. However, in order to suppress the harmful effects caused by the large amount of the organic shrinkage-proofing agent, the content of the other organic shrinkage-proofing agent (based on mass) in the negative electrode electrode material is higher than the content of the organic shrinkage-proofing agent (B) in the negative electrode material. It is preferable that the amount is small. For example, the content (mass basis) of the other organic shrink-proofing agent in the negative electrode material is in the range of 0 to 0.9 times (for example, 0 to 0.5 times) the content of the organic shrinkage-proofing agent (B) in the negative electrode material. , 0 to 0.3 times range, or 0 to 0.1 times range).

A preferred example of the negative electrode material satisfies the following condition (1), and further satisfies the following conditions (2) and / or (3). The example may further satisfy the following conditions (4) and / or (5).
(1) The surface area (Z) of barium sulfate per 1 g of the negative electrode material is 0.04 m ² or more or 0.05 m ² or more. The surface area (Z) may be in the above range.
(2) The average particle size of barium sulfate is 0.5 μm or more and 1.0 μm or less. The average particle size may be in the above range.
(3) The content of barium sulfate in the negative electrode electrode material is 0.9% by mass or more, and is, for example, in the range of 0.9 to 2.8% by mass. The content may be in the above range.
(4) The bisphenol unit is at least one selected from the group consisting of a bisphenol A unit, a bisphenol S unit, and a bisphenol F unit. The bisphenol unit may be a bisphenol A unit and / or a bisphenol S unit. The organic shrinkage proofing agent (B) may be the above-mentioned condensate.
(5) The content of the organic shrinkage barrier (B) contained in the negative electrode electrode material is in the range of 0.01 to 1.0% by mass. The content may be in the above range. The content (mass basis) of the organic shrink-proofing agent other than the organic shrinkage-proofing agent (B) in the negative electrode material may be smaller than the content of the organic shrinkage-proofing agent (B) in the negative electrode material.

The negative electrode material may further contain a predetermined polymer compound other than the organic shrinkage proofing agent (B). The polymer compound may be referred to as "polymer compound (P)" below. The content of the polymer compound (P) in the negative electrode electrode material may be in the range of 100 ppm to 1000 ppm on a mass basis. The content may be less than 100 ppm or more than 1000 ppm. The content may be 50 ppm or more, 100 ppm or more, or 200 ppm or more. The content may be 2000 ppm or less, 1000 ppm or less, 600 ppm or less, or 400 ppm or less. These lower and upper limits can be combined arbitrarily. For example, the content may be in the range of 50 ppm to 600 ppm, the range of 100 ppm to 600 ppm, the range of 200 ppm to 600 ppm, and the range of 200 ppm to 400 ppm.

The first example of the polymer compound (P) is a polymer compound having a peak in the range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent. .. In this specification, ^{1 1} H-NMR spectrum is a spectrum measured using deuterated chloroform as a solvent unless otherwise specified. A second example of the polymer compound (P) is a polymer compound comprising a repeating structure of _{oxyC 2-4} alkylene units. The polymer compound contained in the first example of the polymer compound (P) and the polymer compound contained in the second example of the polymer compound (P) overlap at least in part. As the polymer compound (P), a commercially available one may be used. Alternatively, the polymer compound (P) may be synthesized by a known method.

By adding the polymer compound (P) to the negative electrode material, it is possible to reduce the amount of overcharged electricity, thereby reducing the amount of reduced electrolytic solution. The reason why the amount of overcharged electricity can be reduced by the polymer compound (P) is considered to be as follows. Since the polymer compound (P) contains a repeating structure of an _{oxyC 2-4} alkylene unit and the like, it is easy to form a linear structure. Therefore, the polymer compound (P) added to the negative electrode material covers the surface of lead in the negative electrode material thinly and widely. By covering the surface of lead with the polymer compound (P), the hydrogen overvoltage rises, and as a result, side reactions that generate hydrogen during overcharging are less likely to occur. On the other hand, if the amount of the polymer compound (P) added is large, the charge acceptability may decrease. In the present invention, a specific polymer compound (P) is added to the negative electrode material in a specific amount. As a result, a lead-acid battery having high charge acceptance performance and a small amount of electrolytic solution reduction can be obtained.

The polymer compound (P) preferably contains a repeating structure of _{oxyC 2-4} alkylene units. When a polymer compound (P) containing a repeating structure of an _{oxyC 2-4} alkylene unit is used, the polymer compound (P) is more easily adsorbed to lead and has a linear structure, so that the lead surface is made thinner. It is thought that it will be easier to cover. Therefore, the amount of overcharged electricity can be reduced more effectively, and the effect of suppressing the decrease in charge acceptability can be further enhanced.

The lead-acid battery may be either a control valve type (sealed type) lead-acid battery (VRLA type lead-acid battery) or a liquid type (vent type) lead-acid battery.

In the present specification, the analysis of substances (organic shrink-proofing agent, polymer compound (P), barium sulfate, etc.) in the negative electrode electrode material is performed on the negative electrode of the negative electrode plate taken out from the fully charged lead-acid battery unless otherwise specified. Obtained using an electrode material.

(Explanation of terms)
(Electrode material)
Each electrode material of the negative electrode material and the positive electrode material is usually held in the current collector. The electrode material is a portion of the electrode plate excluding the current collector. Members such as mats and pacing papers may be attached to the electrode plate. Since such a member (also referred to as a sticking member) is used integrally with the plate, it is included in the plate. When the electrode plate includes a sticking member (mat, pacing paper, etc.), the electrode material is a portion of the electrode plate excluding the current collector and the sticking member.

(Polymer compound (P))
The polymer compound (P) satisfies at least one of the following conditions (i) and (ii).
Condition (i)
The polymer compound (P) has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent.
Condition (ii)
The polymer compound (P) contains a repeating structure of _{oxyC 2-4} alkylene units.

In condition (i), the peak in the range of 3.2 ppm or more and 3.8 ppm or less is derived from the oxyC _2-4 alkylene unit. That is, the polymer compound (P) that satisfies the condition (ii) is also the polymer compound (P) that satisfies the condition (i). The polymer compound (P) satisfying the condition (i) may contain a repeating structure of a monomer unit other than the _{oxyC 2-4} alkylene unit, and may have a certain molecular weight. The number average molecular weight (Mn) of the polymer compound (P) satisfying the above (i) or (ii) may be, for example, 300 or more.

(Oxy-C _2-4 alkylene unit)
The Oxy-C _2-4 alkylene unit is a unit represented by -OR ^1- . Here, R ¹ represents a C _2-4 alkylene group (an alkylene group having a carbon number in the range of 2 to 4). R ¹ may contain an alkylene group having a different number of carbon atoms.

(Organic shrinkage agent)
The organic shrink-proofing agent refers to an organic compound among compounds having a function of suppressing the shrinkage of lead, which is a negative electrode active material, when the lead storage battery is repeatedly charged and discharged.

(Number average molecular weight)
The number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used to determine Mn is polyethylene glycol.

(Weight average molecular weight)
The weight average molecular weight (Mw) is determined by GPC. The standard substance used when determining Mw is sodium polystyrene sulfonate.

(Sulfur element content in organic shrink proofing agent)
The content of the sulfur element in the organic shrinkage proofing agent is Xμmol / g means that the content of the sulfur element contained in 1 g of the organic shrinkage proofing agent is Xμmol / g.

(Fully charged)
The fully charged state of a liquid lead-acid battery is defined by the definition of JIS D 5301: 2019. More specifically, in a water tank at 25 ° C ± 2 ° C, charging is performed every 15 minutes with a current (A) 0.2 times the value described as the rated capacity (value whose unit is Ah). The state in which the lead-acid battery is charged is regarded as a fully charged state until the terminal voltage of No. 1 or the electrolyte density converted into temperature at 20 ° C. shows a constant value with three valid digits three times in a row. In the case of a control valve type lead-acid battery, the fully charged state is 0.2 times the current (value with Ah as the unit) described in the rated capacity in the air tank at 25 ° C ± 2 ° C (the unit is Ah). In A), constant current constant voltage charging of 2.23V / cell is performed, and the charging current at the time of constant voltage charging is 0.005 times the value (value with the unit being Ah) described in the rated capacity (A). When it becomes, charging is completed.

A fully charged lead-acid battery is a fully charged lead-acid battery. The lead-acid battery may be fully charged after the chemical conversion, immediately after the chemical conversion, or after a lapse of time from the chemical conversion (for example, after the chemical conversion, the lead-acid battery in use (preferably at the initial stage of use) is fully charged. May be). An initial use battery is a battery that has not been used for a long time and has hardly deteriorated.

(Vertical direction of lead-acid battery or lead-acid battery component)
In the present specification, the vertical direction of the lead-acid battery or the component of the lead-acid battery (plate, battery case, separator, etc.) means the vertical direction of the lead-acid battery in the state where the lead-acid battery is used. Each electrode plate of the positive electrode plate and the negative electrode plate is provided with an ear portion for connecting to an external terminal. In some lead-acid batteries, such as horizontal control valve type lead-acid batteries, the ears are provided so as to project laterally to the sides of the plate, but in many lead-acid batteries, the ears are usually made of the plate. It is provided so as to project upward at the top.

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described for each of the main constituent requirements, but the present invention is not limited to the following embodiments.

[Lead-acid battery]
(Negative electrode plate)
The negative electrode plate includes a negative electrode current collector and a negative electrode material supported by the negative electrode current collector.

(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 sheet or a lead alloy sheet. Examples of the processing method include expanding processing and punching processing. It is preferable to use a grid-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

The lead alloy used for the negative electrode current collector may be any of Pb—Sb based alloy, Pb—Ca based alloy, and Pb—Ca—Sn based alloy. These leads or lead alloys may further contain, as an additive element, at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like. The negative electrode current collector may include a surface layer. The surface layer and the inner layer of the negative electrode current collector may have different compositions. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on the selvage portion of the negative electrode current collector. The surface layer of the selvage portion may contain Sn or a Sn alloy.

(Negative electrode material)
The negative electrode material contains an organic shrinkage proofing agent (B) and barium sulfate. The negative electrode material further contains a negative electrode active material (specifically, lead or lead sulfate) that develops a capacity by a redox reaction. The negative electrode material may contain at least one selected from the group consisting of carbonaceous materials and other additives. Examples of the additive include, but are not limited to, an organic shrinkage proofing agent, barium sulfate, fibers (resin fiber, etc.) and the like. The negative electrode active material in the charged state is spongy lead, but the unchemical negative electrode plate is usually produced by using lead powder.

(Polymer compound (P))
The first example of the polymer compound (P) has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of ¹ H-NMR spectrum. Such polymer compound (P) has an oxyC _2-4 alkylene unit. Examples of the _{oxyC 2-4} alkylene unit contained in the polymer compound (P) include an oxyethylene unit, an oxypropylene unit, an oxytrimethylene unit, an oxy2-methyl-1,3-propylene unit, and an oxy1,4-butylene unit. , Oxy 1,3-butylene unit and the like. The polymer compound (P) may have one kind of such oxyC _2-4 alkylene unit, or may have two or more kinds of such oxyC 2-4 alkylene unit.

The polymer compound (P) preferably contains a repeating structure of _{oxyC 2-4} alkylene units. The repeating structure may contain one type of oxyC _{2-4 alkylene unit, or may contain two or more types of oxy C 2-4 alkylene} unit. The polymer compound (P) may contain one kind of the above-mentioned repeating structure, or may contain two or more kinds of the above-mentioned repeating structures.

The polymer compound (P) having a repeating structure of the _{oxyC 2-4} alkylene unit also includes those classified as surfactants (more specifically, nonionic surfactants).

Examples of the polymer compound (P) include hydroxy compounds having a repeating structure of an _{oxyC 2-4} alkylene unit (poly C _2-4 alkylene glycol, a copolymer containing a repeating structure of an oxy C _2-4 alkylene, and a polyol. Poly C _2-4 alkylene oxide adducts, etc.), etherified or esterified compounds of these hydroxy compounds, and the like. Examples of _{polyC 2-4} alkylene glycols include polyethylene glycol, polypropylene glycol, and polyoxyethylene polyoxypropylene glycol.

Examples of the copolymer include a copolymer containing different oxyC _2-4 alkylene units. The copolymer may be a block copolymer.

In the polymer compound (P) containing the repeating structure of the oxyC _{2-4 alkylene unit, the ratio of the oxy C 2-4 alkylene} unit to all the constituent units may be in the range of 50 mol% to 100 mol%, and may be 60 mol%. It may be in the range of ~ 100 mol% (for example, the range of 75 mol% to 100 mol%), or may be in the range of 60 mol% to 95 mol% (for example, the range of 75 mol% to 95 mol%). Here, the oxyC _2-4 alkylene unit may be an oxyethylene unit and / or an oxypropylene unit.

The polyol may be any of an aliphatic polyol, an alicyclic polyol, an aromatic polyol, a heterocyclic polyol and the like. From the viewpoint that the polymer compound (P) is thin and easily spreads on the lead surface, an aliphatic polyol, an alicyclic polyol (for example, polyhydroxycyclohexane, polyhydroxynorbornane, etc.) and the like are preferable, and an aliphatic polyol is particularly preferable. Examples of the aliphatic polyol include an aliphatic diol, a polyol having a triol or higher (for example, glycerin, trimethylolpropane, pentaerythritol, sugar or a sugar alcohol, etc.). Examples of the aliphatic diol include alkylene glycols having 5 or more carbon atoms. The alkylene glycol may be, for example, C _{5-14 alkylene glycol or C 5-10 alkylene} glycol. Examples of the sugar or sugar alcohol include sucrose, erythritol, xylitol, mannitol, sorbitol and the like. The sugar or sugar alcohol may have either a chain structure or a cyclic structure. In the polyalkylene oxide adduct of the polyol, the alkylene oxide corresponds to the _{oxyC 2-4} alkylene unit of the polymer compound (P) and contains at least C _2-4 alkylene oxide. From the viewpoint that the polymer compound (P) can easily form a linear structure, the polyol is preferably a diol.

The etherified product is composed of a -OH group (a hydrogen atom of the terminal group and an oxygen atom bonded to the hydrogen atom of the terminal group) at least a part of the hydroxy compound having a repeating structure of the above oxyC _2-4 alkylene unit. The —OH group) has ^two etherified —OR groups (in the formula, R ² is an organic group). Of the ends of the polymer compound (P), some ends may be etherified, or all ends may be etherified. For example, one end of the main chain of the linear polymer compound (P) may be an −OH group, and the other end may be an ^−OR2 group.

The esterified product is composed of an OH group (a hydrogen atom of the terminal group and an oxygen atom bonded to the hydrogen atom of the terminal group) at least a part of the hydroxy compound having a repeating structure of the _{oxyC 2-4} alkylene unit. The OH group) has ³ esterified —OC (= O) —R groups (in the formula, R ³ is an organic group). Of the ends of the polymer compound (P), some ends may be esterified, or all ends may be esterified. For example, one end of the main chain of the linear polymer compound (P) may be an −OH group, and the other end may be an —OC ⁽ = O) —R3 group.

Examples of the organic groups R ² and R ³ include hydrocarbon groups. The hydrocarbon group may have a substituent (eg, a hydroxy group, an alkoxy group, and / or a carboxy group). The hydrocarbon group may be any of an aliphatic, alicyclic, and aromatic group. The aromatic hydrocarbon group and the alicyclic hydrocarbon group may have an aliphatic hydrocarbon group (for example, an alkyl group, an alkenyl group, an alkynyl group, etc.) as a substituent. The number of carbon atoms of the aliphatic hydrocarbon group as a substituent may be, for example, 1 to 30, 1 to 20, 1 to 10, and 1 to 6 or 1 to 4. May be.

Examples of the aromatic hydrocarbon group include an aromatic hydrocarbon group having 24 or less carbon atoms (for example, 6 to 24). The number of carbon atoms of the aromatic hydrocarbon group may be 20 or less (for example, 6 to 20), 14 or less (for example, 6 to 14) or 12 or less (for example, 6 to 12). Examples of the aromatic hydrocarbon group include an aryl group and a bisaryl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the bisaryl group include a monovalent group corresponding to bisarene. Examples of the bisarene include biphenyl and bisarylalkane (for example, _bisC 6-10aryl C _1-4 alkane (for example, 2,2-bisphenylpropane)).

Examples of the alicyclic hydrocarbon group include an alicyclic hydrocarbon group having 16 or less carbon atoms. The alicyclic hydrocarbon group may be a crosslinked cyclic hydrocarbon group. The alicyclic hydrocarbon group may have 10 or less or 8 or less carbon atoms. The alicyclic hydrocarbon group has, for example, 5 or more carbon atoms, and may be 6 or more carbon atoms.

The number of carbon atoms of the alicyclic hydrocarbon group may be 5 (or 6) or more and 16 or less, 5 (or 6) or more and 10 or less, or 5 (or 6) or more and 8 or less.

Examples of the alicyclic hydrocarbon group include a cycloalkyl group (cyclopentyl group, cyclohexyl group, cyclooctyl group, etc.), a cycloalkenyl group (cyclohexenyl group, cyclooctenyl group, etc.) and the like. The alicyclic hydrocarbon group also includes the hydrogenated additive of the above aromatic hydrocarbon group.

Of the hydrocarbon groups, an aliphatic hydrocarbon group is preferable from the viewpoint that the polymer compound (P) is thinly adhered to the lead surface. Aliphatic hydrocarbon groups may be saturated or unsaturated. Examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, a dienyl group having two carbon-carbon double bonds, and a trienyl group having three carbon-carbon double bonds. The aliphatic hydrocarbon group may be linear or branched.

The aliphatic hydrocarbon group may have, for example, 30 or less, 26 or less or 22 or less, 20 or less or 16 or less, 14 or less or 10 or less. It may be 8 or less or 6 or less. The lower limit of the number of carbon atoms is 1 or more for an alkyl group, 2 or more for an alkenyl group and an alkynyl group, 3 or more for a dienyl group, and 4 or more for a trienyl group, depending on the type of the aliphatic hydrocarbon group. From the viewpoint that the polymer compound (P) is thin and easily adheres to the lead surface, an alkyl group or an alkenyl group is particularly preferable.

Specific examples of the alkyl group include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, i-pentyl, and s-pentyl. 3-Pentyl, t-Pentyl, n-hexyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, i-decyl, undecyl, lauryl (dodecyl), tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl. , Ikosil, Henikosil, Behenil and the like.

Specific examples of the alkenyl group include vinyl, 1-propenyl, allyl, cis-9-heptadecene-1-yl, palmitrail, oleyl and the like. The alkenyl group may be, for example, a C _2-30 alkenyl group or a C _2-26 alkenyl group, a C _2-22 alkenyl group or a C _2-20 alkenyl group, and a C _10-20 alkenyl group. May be.

The polymer compound (P) is selected from the group consisting of an etherified product of a hydroxy compound having a repeating structure of an _{oxyC 2-4 alkylene unit and an esterified product of a hydroxy compound having a repeating structure of an oxy C 2-4 alkylene} unit. It is preferable to use at least one of them because the effect of suppressing the decrease in charge acceptability can be further enhanced. Further, even when these polymer compounds (P) are used, the amount of overcharge electricity can be reduced. Further, among such polymer compounds (P), those having a repeating structure of an oxypropylene unit, those having a repeating structure of an oxyethylene unit, and the like are preferable.

The polymer compound (P) may have one or more hydrophobic groups. Examples of the hydrophobic group include aromatic hydrocarbon groups, alicyclic hydrocarbon groups, and long-chain aliphatic hydrocarbon groups among the above-mentioned hydrocarbon groups. Examples of the long-chain aliphatic hydrocarbon group include those having 8 or more carbon atoms among the above-mentioned aliphatic hydrocarbon groups (alkyl group, alkenyl group, etc.), preferably 12 or more, and more preferably 16 or more. Among them, the polymer compound (P) having a long-chain aliphatic hydrocarbon group is preferable because it is unlikely to cause excessive adsorption to lead and the effect of suppressing a decrease in charge acceptability is further enhanced. In the polymer compound (P), at least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group. The carbon number of the long-chain aliphatic hydrocarbon group may be 30 or less, 26 or less, or 22 or less.

The number of carbon atoms of a long-chain aliphatic hydrocarbon group is 8 or more (or 12 or more) 30 or less, 8 or more (or 12 or more) 26 or less, 8 or more (or 12 or more) 22 or less, 10 or more and 30 or less (or 26 or less). ), Or it may be 10 or more and 22 or less.

Among the polymer compounds (P), those having a hydrophilic group and a hydrophobic group correspond to a nonionic surfactant. The repeating structure of the oxyethylene unit exhibits high hydrophilicity and can be a hydrophilic group in nonionic surfactants. Therefore, it is preferable that the polymer compound (P) having a hydrophobic group described above contains a repeating structure of an oxyethylene unit. Due to the balance between hydrophobicity and high hydrophilicity due to the repeating structure of the oxyethylene unit, such a polymer compound (P) selectively adsorbs lead, but excessively covers the surface of lead. Since it can be suppressed, the effect of suppressing the decrease in charge acceptability can be further enhanced while reducing the amount of overcharged electricity. Such a polymer compound (P) can ensure high adsorptivity to lead even if it has a relatively low molecular weight (for example, Mn is 1000 or less).

Among the above polymer compounds (P), a polyoxypropylene-polyoxyethylene block copolymer, an etherified product of a hydroxy compound having a repeating structure of an oxyethylene unit, an esterified product of a hydroxy compound having a repeating structure of an oxyethylene unit, and the like. Corresponds to a nonionic surfactant.

Examples of the polymer compound (P) having a hydrophobic group and containing a repeating structure of an oxyethylene unit include an etherified product of polyethylene glycol (alkyl ether and the like), an esterified product of polyethylene glycol (carboxylic acid ester and the like), and polyethylene of the above-mentioned polyol. Examples thereof include an etherified product of an oxide adduct (alkyl ether and the like), an esterified product of a polyethylene oxide adduct of the above-mentioned polyol (polyol and higher polyol, etc.) (carboxylic acid ester and the like), and the like. Specific examples of such a polymer compound (P) include polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene coconut oil fatty acid sorbitan, polyoxyethylene sorbitan oleate, and stearer. Examples thereof include, but are not limited to, polyoxyethylene sorbitan acid, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether. Above all, it is preferable to use an esterified product of polyethylene glycol, an esterified product of the polyethylene oxide adduct of the above-mentioned polyol, or the like because higher charge acceptability can be ensured and the amount of overcharged electricity can be remarkably reduced.

From the viewpoint that the effect of reducing the amount of overcharged electricity is further enhanced and it is easy to secure higher charge acceptability, it is also preferable that the repeating structure of the _{oxyC 2-4} alkylene includes at least the repeating structure of the oxypropylene unit. In this case, the charge acceptability tends to be lower than in the case of the repeating structure of the oxyethylene unit, but even in this case, high charge acceptability should be ensured while keeping the amount of overcharge electricity low. Can be done. The polymer compound (P) containing the oxypropylene unit has a peak derived from -CH <and -CH _2- of the oxypropylene unit in the range of 3.2 ppm to 3.8 ppm in the chemical shift of ¹ H-NMR spectrum. Have. Since the electron densities around the nuclei of hydrogen atoms in these groups are different, the peaks are split. Such a polymer compound (P) peaks in, for example, in the range of 3.2 ppm or more and 3.42 ppm or less and in the range of more than 3.42 ppm and 3.8 ppm or less in the chemical shift of ¹ H-NMR spectrum. Has. Peaks in the range of 3.2 ppm or more and 3.42 ppm or less are derived from -CH _2- , and peaks in the range of more than 3.42 ppm and 3.8 ppm or less are derived from -CH <and -CH _2- .

Examples of the polymer compound (P) containing at least the repeating structure of the oxypropylene unit include polypropylene glycol, a copolymer containing the repeating structure of the oxypropylene unit, a polypropylene oxide adduct of the above-mentioned polyol, an etherified product or an esterified product thereof. Can be mentioned. Examples of the copolymer include an oxypropylene-oxyalkylene copolymer (however, the oxyalkylene is C _2-4 alkylene other than oxypropylene). Examples of the oxypropylene-oxyalkylene copolymer include an oxypropylene-oxyethylene copolymer and an oxypropylene-oxytrimethylene copolymer. The oxypropylene-oxyalkylene copolymer may be referred to as a polyoxypropylene-polyoxyalkylene copolymer (for example, a polyoxypropylene-polyoxyethylene copolymer). The oxypropylene-oxyalkylene copolymer may be a block copolymer (for example, a polyoxypropylene-polyoxyethylene block copolymer). Examples of the etherified product include polypropylene glycol alkyl ether, alkyl ether of an oxypropylene-oxyalkylene copolymer (alkyl ether of a polyoxypropylene-polyoxyethylene copolymer, etc.) and the like. Examples of the esterified product include a polypropylene glycol ester of a carboxylic acid and a carboxylic acid ester of an oxypropylene-oxyalkylene copolymer (such as a carboxylic acid ester of a polyoxypropylene-polyoxyethylene copolymer).

Examples of the polymer compound (P) containing at least the repeating structure of the oxypropylene unit include polypropylene glycol, polyoxypropylene-polyoxyethylene copolymer (polyoxypropylene-polyoxyethylene block copolymer, etc.), and polyoxyethylene. -Polyoxypropylene alkyl ether (such as an alkyl ether (such as butyl ether) in which R ² is an alkyl having 10 or less carbon atoms (or 8 or less or 6 or less)), polypropylene glycol carboxylate (R ³ above is 10 or less carbon atoms (or more). Alternatively, polypropylene glycol carboxylate (polypropylene glycol acetate, etc.) which is an alkyl of 8 or less or 6 or less), polypropylene oxide adduct of polyol of triol or more (polypropylene oxide adduct of glycerin, etc.), and polymer compounds (such as polypropylene oxide adduct of glycerin) can be mentioned. P) is not limited to these.

In the polymer compound (P) containing the repeating structure of the oxypropylene unit, the proportion of the oxypropylene unit is, for example, 5 mol% or more, and may be 10 mol% or more or 20 mol% or more. The proportion of the oxypropylene unit is, for example, 100 mol% or less. In the above copolymer, the proportion of the oxypropylene unit may be 90 mol% or less, 75 mol% or less, or 60 mol% or less.

In the polymer compound (P) containing the repeating structure of the oxypropylene unit, the proportion of the oxypropylene unit is 5 mol% or more and 100 mol% or less (or 90 mol% or less), 10 mol% or more and 100 mol% or less (or 90 mol% or less), 20 mol%. 100 mol% or less (or 90 mol% or less), 5 mol% or more and 75 mol% or less (or 60 mol% or less), 10 mol% or more and 75 mol% or less (or 60 mol% or less), or 20 mol% or more and 75 mol% or less (or 60 mol% or less) May be.

The polymer compound (P) preferably contains a large amount of _{oxyC 2-4} alkylene unit from the viewpoint of increasing the adsorptivity of the polymer compound (P) to lead and facilitating the formation of a linear structure. Such a polymer compound (P) contains, for example, an oxygen atom bonded to a terminal group and an -CH ₂ -group and / or -CH <group bonded to the oxygen atom. In the ¹ H-NMR spectrum of the polymer compound (P), the integrated value V ₁ of the peak of 3.2 ppm to 3.8 ppm occupies a large proportion of the total V _SUM of the integrated value of the predetermined peak. Here, the total V _SUM of the integrated values of the peaks is the sum of the integrated values V ₁ and the integrated values of the peaks of -CH ₂ -group hydrogen atoms and the integrated value of the peaks of -CH <group hydrogen atoms. be. This ratio is, for example, 50% or more, and may be 80% or more. From the viewpoint that the effect of reducing the amount of overcharged electricity is further enhanced and it is easy to secure higher charge acceptability, the above ratio is preferably 85% or more, and more preferably 90% or more. For example, when the polymer compound (P) has a -OH group at the terminal and has a -CH ₂ -group or -CH <group bonded to the oxygen atom of this -OH group, ¹ in the H-NMR spectrum, -CH. The peaks of hydrogen atoms of ₂ -group and -CH <group are in the range of chemical shift exceeding 3.8 ppm and 4.0 ppm or less.

The negative electrode material may contain one kind of polymer compound (P), or may contain two or more kinds.

The polymer compound (P) may contain, for example, a compound having Mn of 5 million or less, a compound of 3 million or less or 2 million or less, a compound of 500,000 or less or 100,000 or less, and 50,000. It may contain the following compounds or compounds of 20000 or less. From the viewpoint of ensuring higher charge acceptability, the polymer compound (P) preferably contains a compound having a Mn of 10,000 or less, and may contain a compound of 5000 or less or 4000 or less, and a compound of 3000 or less or 2500 or less. May include. The Mn of such a compound may be 300 or more, 400 or more, or 500 or more. From the viewpoint of further enhancing the effect of reducing the amount of overcharged electricity, the Mn of such a compound is preferably 1000 or more, and more preferably 1500 or more or 1800 or more. As the polymer compound (P), two or more kinds of compounds having different Mns may be used. That is, the polymer compound (P) may have a plurality of Mn peaks in the molecular weight distribution.

The Mn of the above compound is 300 or more (or 400 or more) 5 million or less, 300 or more (or 400 or more) 3 million or less, 300 or more (or 400 or more) 2 million or less, 300 or more (or 400 or more) 500,000 or less. , 300 or more (or 400 or more) 100,000 or less, 300 or more (or 400 or more) 50,000 or less, 300 or more (or 400 or more) 20000 or less, 300 or more (or 400 or more) 10000 or less, 300 or more (or 400 or more) 5000 Below, 300 or more (or 400 or more) 4000 or less, 300 or more (or 400 or more) 3000 or less, 300 or more (or 400 or more) 2500 or less, 500 or more (or 1000 or more) 5 million or less, 500 or more (or 1000 or more) 3 million or less, 500 or more (or 1000 or more) 2 million or less, 500 or more (or 1000 or more) 500,000 or less, 500 or more (or 1000 or more) 100,000 or less, 500 or more (or 1000 or more) 50,000 or less, 500 or more ( Or 1000 or more) 20000 or less, 500 or more (or 1000 or more) 10000 or less, 500 or more (or 1000 or more) 5000 or less, 500 or more (or 1000 or more) 4000 or less, 500 or more (or 1000 or more) 3000 or less, 500 or more (or 500 or more) Or 1000 or more) 2500 or less, 1500 or more (or 1800 or more) 5 million or less, 1500 or more (or 1800 or more) 3 million or less, 1500 or more (or 1800 or more) 2 million or less, 1500 or more (or 1800 or more) 500,000 or less 1500 or more (or 1800 or more) 100,000 or less, 1500 or more (or 1800 or more) 50,000 or less, 1500 or more (or 1800 or more) 20000 or less, 1500 or more (or 1800 or more) 10,000 or less, 1500 or more (or 1800 or more) 5000 Below, it may be 1500 or more (or 1800 or more) 4000 or less, 1500 or more (or 1800 or more) 3000 or less, or 1500 or more (or 1800 or more) 2500 or less.

The content of the polymer compound (P) in the negative electrode electrode material is, for example, 8 ppm or more and may be 10 ppm or more on a mass basis. From the viewpoint of further enhancing the effect of reducing the amount of overcharged electricity, the content of the polymer compound (P) in the negative electrode electrode material is preferably 20 ppm or more, more preferably 30 ppm or more on a mass basis. The content of the polymer compound (P) in the negative electrode electrode material is, for example, 1000 ppm or less, may be less than 1000 ppm, may be 700 ppm or less, and may be 600 ppm or less or 500 ppm or less on a mass basis. May be good. From the viewpoint of easily ensuring higher charge acceptability, the content of the polymer compound (P) in the negative electrode electrode material is preferably 400 ppm or less, more preferably 300 ppm or less, and 200 ppm or less or 160 ppm or less on a mass basis. It may be 150 ppm or less, 120 ppm or less, or 100 ppm or less.

The content (mass basis) of the polymer compound (P) in the negative electrode electrode material is 8 ppm or more (or 10 ppm or more) 1000 ppm or less, 8 ppm or more (or 10 ppm or more) less than 1000 ppm, 8 ppm or more (or 10 ppm or more) 700 ppm or less, 8 ppm. More than (or 10ppm or more) 600ppm or less, 8ppm or more (or 10ppm or more) 500ppm or less, 8ppm or more (or 10ppm or more) 400ppm or less, 8ppm or more (or 10ppm or more) 300ppm or less, 8ppm or more (or 10ppm or more) 200ppm or less, 8ppm More than (or 10ppm or more) 160ppm or less, 8ppm or more (or 10ppm or more) 150ppm or less, 8ppm or more (or 10ppm or more) 120ppm or less, 8ppm or more (or 10ppm or more) 100ppm or less, 20ppm or more (or 30ppm or more) 1000ppm or less, 20ppm More than (or 30ppm) less than 1000ppm, 20ppm or more (or 30ppm or more) 700ppm or less, 20ppm or more (or 30ppm or more) 600ppm or less, 20ppm or more (or 30ppm or more) 500ppm or less, 20ppm or more (or 30ppm or more) 400ppm or less, 20ppm More than (or 30ppm or more) 300ppm or less, 20ppm or more (or 30ppm or more) 200ppm or less, 20ppm or more (or 30ppm or more) 160ppm or less, 20ppm or more (or 30ppm or more) 150ppm or less, 20ppm or more (or 30ppm or more) 120ppm or less, or It may be 20 ppm or more (or 30 ppm or more) and 100 ppm or less.

(Organic shrinkage agent)
Organic shrinkage proofing agents are usually roughly classified into lignin compounds and synthetic organic shrinkage proofing agents. It can be said that the synthetic organic shrinkage proofing agent is an organic shrinkage proofing agent other than the lignin compound. Examples of the organic shrinkage proofing agent contained in the negative electrode electrode material include lignin compounds and synthetic organic shrinkage proofing agents. The negative electrode electrode material may contain one kind of organic shrinkage proofing agent, or may contain two or more kinds of organic shrinkage proofing agents. Examples of the organic shrinkage proofing agent (B) include some of the synthetic organic shrinkage proofing agents described below.

Examples of the lignin compound include lignin and lignin derivatives. Examples of the lignin derivative include lignin sulfonic acid or a salt thereof (alkali metal salt (sodium salt, etc.), etc.).

The synthetic organic shrinkage proofing agent is an organic polymer containing a sulfur element, and generally contains a plurality of aromatic rings in the molecule and also contains a sulfur element as a sulfur-containing group. 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 be present in acid form or may be present in salt form such as Na salt.
Is suppressed, and high charge acceptability can be ensured.

As the organic shrinkage proofing agent, it is also preferable to use a condensate containing at least a unit of an aromatic compound. Examples of such a condensate include a condensate of an aromatic compound made of an aldehyde compound (such as at least one selected from the group consisting of aldehydes (eg, formaldehyde) and condensates thereof). The organic shrinkage proofing agent may contain a unit of one kind of aromatic compound, or may contain a unit of two or more kinds of aromatic compounds. The unit of the aromatic compound means a unit derived from the aromatic compound incorporated in the condensate. The condensate using the bisphenol compound as the aromatic compound is contained in the organic shrinkage proofing agent (B).

Examples of the aromatic ring contained in the aromatic compound include a benzene ring and a naphthalene ring. When the aromatic compound has a plurality of aromatic rings, the plurality of aromatic rings may be directly bonded or linked by a linking group (for example, an alkylene group (including an alkylidene group), a sulfone group) or the like. Examples of such a structure include a bisarene structure (biphenyl, bisphenylalkane, bisphenylsulfone, etc.). Examples of the aromatic compound include compounds having the above aromatic ring and at least one selected from the group consisting of a hydroxy group and an amino group. The hydroxy group or amino group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having a hydroxy group or an amino group. The hydroxy group also includes a salt of the hydroxy group (-OMe). The amino group also includes a salt of the amino group (specifically, a salt with an anion). Examples of Me include alkali metals (Li, K, Na, etc.), Group 2 metals of the periodic table (Ca, Mg, etc.) and the like.

Examples of the aromatic compound include bisarene compounds [bisphenol compounds, hydroxybiphenyl compounds, bisarene compounds having an amino group (bisarylalkane compounds having an amino group, bisarylsulfone compounds having an amino group, biphenyl compounds having an amino group, etc.), and the like. Hydroxyarene compounds (hydroxynaphthalene compounds, phenol compounds, etc.), aminoarene compounds (aminonaphthalene compounds, aniline compounds (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc.), etc.), etc.] are preferable. The aromatic compound may further have a substituent. The organic shrinkage proofing agent may contain one kind of residues of these compounds, or may contain a plurality of kinds. As the bisphenol compound, bisphenol A, bisphenol S, bisphenol F and the like are preferable.

The condensate preferably contains at least a unit of an aromatic compound having a sulfur-containing group. Above all, it is advantageous to use a condensate containing at least a unit of a bisphenol compound having a sulfur-containing group in order to secure higher charge acceptability. From the viewpoint of enhancing the effect of reducing the amount of overcharged electricity, it is also preferable to use a condensate of a naphthalene compound having an aldehyde compound having a sulfur-containing group and at least one selected from the group consisting of a hydroxy group and an amino group. ..

The sulfur-containing group may be directly bonded to the aromatic ring contained in the compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example. The sulfur-containing group is not particularly limited, and examples thereof include a sulfonyl group, a sulfonic acid group, or a salt thereof.

Further, as the organic shrinkage proofing agent, for example, a condensation containing at least one selected from the group consisting of a unit of the above-mentioned bisarene compound and a unit of a monocyclic aromatic compound (hydroxyarene compound and / or aminoarene compound, etc.). At least one may be used. The organic shrinkage proofing agent may contain at least a condensate containing a unit of a bisarene compound and a unit of a monocyclic aromatic compound (particularly, a hydroxyarene compound). Examples of such a condensate include a condensate of a bis-alene compound and a monocyclic aromatic compound made of an aldehyde compound. As the hydroxyarene compound, a phenol sulfonic acid compound (such as phenol sulfonic acid or a substitute thereof) is preferable. As the aminoarene compound, aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid and the like are preferable. As the monocyclic aromatic compound, a hydroxyarene compound is preferable.

Among the above-mentioned organic shrinkage proofing agents, the negative electrode electrode material may contain, for example, an organic shrinkage proofing agent (first organic shrinkage proofing agent) having a sulfur element content of 2000 μmol / g or more. Examples of the first organic shrinkage proofing agent include the above-mentioned synthetic organic shrinkage proofing agent (the above-mentioned condensate and the like).

The sulfur element content of the first organic shrinkage proofing agent may be 2000 μmol / g or more, and preferably 3000 μmol / g or more. The upper limit of the sulfur element content of the organic shrinkage proofing agent is not particularly limited, and from the viewpoint of further enhancing the effect of reducing the amount of overcharged electricity, it is preferably 9000 μmol / g or less, and more preferably 8000 μmol / g or less.

Even if the sulfur element content of the first organic shrinkage proofing agent is, for example, 2000 μmol / g or more (or 3000 μmol / g or more) 9000 μmol / g or less, or 2000 μmol / g or more (or 3000 μmol / g or more) 8000 μmol / g or less. good.

The first organic shrinkage proofing agent contains a condensate containing a unit of an aromatic compound having a sulfur-containing group, and the condensate may contain at least a unit of a bisphenol compound as a unit of the aromatic compound. That is, the first organic shrinkage proofing agent may be the organic shrinkage proofing agent (B). In that case, in this specification, the first organic shrinkage proofing agent can be read as the organic shrinkage proofing agent (B).

The weight average molecular weight (Mw) of the first organic shrinkage proofing agent is preferably 7,000 or more. The Mw of the first organic shrinkage proofing agent is, for example, 100,000 or less, and may be 20,000 or less.

The negative electrode material can contain, for example, an organic shrinkage proofing agent (second organic shrinkage proofing agent) having a sulfur element content of less than 2000 μmol / g. Examples of the second organic shrinkage proofing agent include lignin compounds, synthetic organic shrinkage proofing agents (for example, bisphenol condensates) and the like among the above-mentioned organic shrinkage proofing agents. The sulfur element content of the second organic shrinkage proofing agent is preferably 1000 μmol / g or less, and may be 800 μmol / g or less. The lower limit of the sulfur element content in the second organic shrinkage proofing agent is not particularly limited, but is, for example, 400 μmol / g or more.

The Mw of the second organic shrinkage proofing agent is, for example, less than 7000. The Mw of the second organic shrinkage proofing agent is, for example, 3000 or more.

The negative electrode electrode material may contain a second organic shrinkage proofing agent in addition to the first organic shrinkage proofing agent. When the first organic shrinkage proofing agent and the second organic shrinkage proofing agent are used in combination, the mass ratios thereof can be arbitrarily selected.

The content of the organic shrinkage-proofing agent contained in the negative electrode electrode material is, for example, 0.005% by mass or more, and may be 0.01% by mass or more. When the content of the organic shrink proofing agent is in such a range, a high low temperature and high rate discharge capacity can be ensured. The content of the organic shrinkage proofing agent is, for example, 1.0% by mass or less, and may be 0.5% by mass or less. From the viewpoint of further enhancing the effect of suppressing the decrease in charge acceptability, the content of the organic shrinkage proofing agent is preferably 0.3% by mass or less, more preferably 0.25% by mass or less, 0.2% by mass or less, or It is more preferably 0.15% by mass or less, and may be 0.12% by mass or less.

The content of the organic shrinkage barrier contained in the negative electrode electrode material is 0.005% by mass or more (or 0.01% by mass) 1.0% by mass or less, 0.005% by mass or more (or 0.01% by mass). (More than) 0.5% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) 0.3% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) 0.25% by mass % Or less, 0.005% by mass or more (or 0.01% by mass or more) 0.2% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) 0.15% by mass or less, or 0. It may be 005% by mass or more (or 0.01% by mass or more) and 0.12% by mass or less.

(Carbonaceous material)
As the carbonaceous material contained in the negative electrode electrode material, carbon black, graphite, hard carbon, soft carbon and the like can be used. Examples of carbon black include acetylene black, furnace black, and lamp black. Furness Black also includes Ketjen Black (trade name). The graphite may be any carbonaceous material containing a graphite-type crystal structure, and may be either artificial graphite or natural graphite. The negative electrode material may contain one kind of carbonaceous material, or may contain two or more kinds of carbonaceous material.

The content of the carbonaceous material in the negative electrode electrode material is, for example, 0.05% by mass or more, and may be 0.10% by mass or more. The content of the carbonaceous material is, for example, 5% by mass or less, and may be 3% by mass or less.

The content of the carbonaceous material in the negative electrode material is 0.05% by mass or more and 5% by mass or less, 0.05% by mass or more and 3% by mass or less, 0.10% by mass or more and 5% by mass or less, or 0.10. It may be mass% or more and 3 mass% or less.

(Analysis of negative electrode material or constituents)
The method of analyzing the negative electrode material or its constituent components will be described below. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate. Wash with water by pressing the pH test paper against the surface of the negative electrode plate washed with water until it is confirmed that the color of the test paper does not change. However, the time for washing with water shall be within 2 hours. The negative electrode plate washed with water is dried at 60 ± 5 ° C. for about 6 hours in a reduced pressure environment. If the negative electrode plate contains a sticking member, the sticking member is removed as necessary. Next, a sample (hereinafter referred to as sample A) is obtained by separating the negative electrode material from the negative electrode plate. Sample A is pulverized as needed and subjected to analysis. By measuring the mass of the sample A, the mass of the negative electrode material in the negative electrode plate can be obtained.

(1) Measurement of surface area and content of barium sulfate A crushed sample A is used for measuring the surface area of barium sulfate in the negative electrode material. The measurement is performed by the following procedure. First, 500 mL of nitric acid (concentration: 20% by mass) is added to 100 g of the crushed sample A, and the mixture is heated for about 20 minutes to dissolve the lead component. By filtering the liquid thus obtained, solids such as carbonaceous materials and barium sulfate are filtered out. After the obtained solid content is dispersed in water to form a dispersion liquid, a carbonaceous material and components other than barium sulfate (for example, a reinforcing material) are removed from the dispersion liquid using a sieve. Next, the dispersion liquid is suction-filtered using a membrane filter. The membrane filter is dried in a dryer at 110 ° C. ± 5 ° C. together with the sample filtered by this filtration. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. The dried mixed sample (hereinafter, may be referred to as "Sample C") is collected from the membrane filter.

Next, the mass (M (C + Ba)) of the recovered sample C is measured. Then, the surface area (S (C + Ba)) of the sample C is measured by the nitrogen adsorption (BET) method. Subsequently, the sample C whose surface area has been measured is dispersed in a 100 mL aqueous solution to obtain a dispersion liquid. The aqueous solution has a NaOH concentration of 1 mol / L and an EDTA concentration of 0.3 mol / L. Barium sulfate is dissolved by stirring the obtained dispersion at 40 ° C. for 20 hours. Only the carbonaceous material can be obtained by filtering the liquid thus obtained and drying the filtered solid content. The mass (M (C)) of the obtained carbonaceous material is measured. Further, the surface area (S (C)) of the obtained carbonaceous material is measured by the nitrogen adsorption (BET) method. By subtracting the surface area S (C) from the surface area (S (C + Ba)), the surface area (S (Ba)) of barium sulfate can be obtained. By dividing the surface area (S (Ba)) by the mass of sample A (here, 100 g), the surface area (Z) of barium sulfate per 1 g of the negative electrode material can be obtained. By subtracting the mass (M (C)) from the mass (M (C + Ba)), the mass (M (Ba)) of barium sulfate is obtained. The mass (M (Ba) and the mass of sample A (negative electrode electrode material) ( Here, the content (mass%) of barium sulfate in the negative electrode electrode material can be determined from 100 g).

(2) Measurement of average particle size of barium sulfate For the measurement of the average particle size of barium sulfate in the negative electrode material, sample A is used without pulverization. First, 50 mL of nitric acid (concentration: 20% by mass) is added to 10 g of sample A, and the lead component is dissolved by heating for about 20 minutes. By filtering the liquid thus obtained, solids such as carbonaceous materials and barium sulfate are filtered out. After the obtained solid content is dispersed in water to form a dispersion liquid, components other than the carbonaceous material and barium sulfate (for example, a reinforcing material) are removed from the dispersion liquid using a sieve. Next, the dispersion liquid is suction-filtered using a membrane filter whose mass has been measured in advance, and the solid content is filtered off. The membrane filter is dried together with the filtered sample (solid content) in a dryer at 110 ° C. ± 5 ° C. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. This mixed sample is observed with a scanning electron microscope (SEM) and EDS analysis is performed. By this observation and analysis, barium sulfate (barium sulfate particles) is identified and its particle size is measured. Here, the particle size is a diameter equivalent to a circle. The particle size is measured for 1000 arbitrarily selected barium sulfate particles, and the average value of the measured particle sizes is taken as the average particle size of barium sulfate. That is, the average particle size of barium sulfate means the average particle size measured by the method described here.

(3) Analysis of polymer compound (P) (3-1) Qualitative analysis of polymer compound (P) Grinded sample A is used. 150.0 ± 0.1 mL of chloroform is added to 100.0 ± 0.1 g of sample A, and the mixture is stirred at 20 ± 5 ° C. for 16 hours to extract the polymer compound (P). Then, the solid content is removed by filtration. Infrared spectroscopy, ultraviolet-visible absorption spectrum, NMR spectrum, LC-MS and heat of the chloroform solution in which the polymer compound (P) obtained by extraction is dissolved or the polymer compound (P) obtained by drying the chloroform solution. The polymer compound (P) is identified by obtaining information from at least one selected from the degraded GC-MS.

Chloroform-soluble components are recovered from the chloroform solution in which the polymer compound (P) obtained by extraction is dissolved by distilling off chloroform under reduced pressure. The chloroform-soluble component is dissolved in deuterated chloroform, and the ¹ H-NMR spectrum is measured under the following conditions. From this ¹ H-NMR spectrum, a peak with a chemical shift in the range of 3.2 ppm or more and 3.8 ppm or less is confirmed. Further, the type of _{oxyC 2-4} alkylene unit is specified from the peak in this range.

Device: AL400 type nuclear magnetic resonance device manufactured by JEOL Ltd. Observation frequency: 395.88 MHz
Pulse width: 6.30 μs
Pulse repetition time: 74.1411 seconds Total number of times: 32
Measurement temperature: Room temperature (20-35 ° C)
Criteria: 7.24 ppm
Sample tube diameter: 5 mm

¹ From the 1 H-NMR spectrum, the integral value (V ₁ ) of the peaks in which the chemical shift exists in the range of 3.2 ppm or more and 3.8 ppm or less is obtained. Further, for each of the hydrogen atoms of -CH ₂ -group and -CH <group bonded to the oxygen atom bonded to the terminal group of the polymer compound (P), the sum of the integrated values of the peaks in the ¹ H-NMR spectrum (1). Find V ₂ ). Then, from V ₁ and V ₂ , the ratio of V ₁ to the total of V ₁ and V ₂ (= V ₁ / (V ₁ + V ₂ ) × 100 (%)) is obtained.

In the qualitative analysis, when the integral value of the peak in the ¹ H-NMR spectrum is obtained, two points in the ¹ H-NMR spectrum having no significant signal so as to sandwich the corresponding peak are determined, and these two points are determined. Each integrated value is calculated using the straight line connecting the intervals as the baseline. For example, for a peak in which the chemical shift is in the range of 3.2 ppm to 3.8 ppm, the straight line connecting the two points of 3.2 ppm and 3.8 ppm in the spectrum is used as the baseline. For example, for a peak in which the chemical shift exceeds 3.8 ppm and exists in the range of 4.0 ppm or less, the straight line connecting the two points of 3.8 ppm and 4.0 ppm in the spectrum is used as the baseline.

(3-2) Quantitative analysis of polymer compound (P) The appropriate amount of the above chloroform-soluble component was dissolved in deuterated chloroform together with _mr (g) tetrachloroethane (TCE) measured with an accuracy of ± 0.0001 g. , 1 Measure the ¹ H-NMR spectrum. The integral value (S _a ) of the peak in which the chemical shift is in the range of 3.2 to 3.8 ppm and the integral value (S _r ) of the peak derived from TCE are obtained, and the polymer compound in the negative electrode electrode material is obtained from the following formula. The mass-based content rate _Cn (ppm) of (P) is determined.

C _n = S _a / S _r × N _r / N _a × _Ma / _{Mr × m r /} m × 1000000
(In the formula, Ma is the molecular weight of the structure in which the chemical shift peaks in the range of 3.2 to 3.8 ppm (more specifically, the molecular weight of the repeating structure of the _{oxyC 2-4} alkylene unit), and N _a is the number of hydrogen atoms bonded to the carbon atom of the main chain of the repeating structure. Nr _{and Mr} are the number of hydrogens contained in the molecule of the reference substance and the molecular weight of the reference substance, respectively, and m (g) is the extraction. It is the mass of the negative electrode material used in.)
Since the reference substance in this analysis is TCE, N _r = 2 and _Mr = 168. Moreover, m = 100.

_For example, when the polymer compound (P) is polypropylene glycol, Ma is 58 and _Na is 3. When the polymer compound (P) is polyethylene glycol, _Ma is 44 and _Na is 4. _Na and _Ma are values obtained by averaging the _Na value and _Ma value of each monomer unit using the molar ratio (mol%) of each monomer unit contained in the repeating structure.

In the quantitative analysis, the integrated value of the peak in the ¹ H-NMR spectrum is obtained by using the data processing software "ALICE" manufactured by JEOL Ltd.

(3-3) Mn measurement of the polymer compound (P) Using the above chloroform-soluble component, GPC measurement of the polymer compound (P) is performed using the following apparatus under the following conditions. Separately, a calibration curve (calibration curve) is created from the plot of Mn of the standard material and the elution time. The Mn of the polymer compound (P) is calculated based on the calibration curve and the GPC measurement result of the polymer compound (P). However, the esterified product or the etherified product may be in a decomposed state in the chloroform-soluble component.

Analysis system: 20A system (manufactured by Shimadzu Corporation)
Column: GPC KF-805L (manufactured by Shodex) connected in series Column temperature: 30 ° C ± 1 ° C
Mobile phase: Tetrahydrofuran Flow rate: 1 mL / min.
Concentration: 0.20% by mass
Injection volume: 10 μL
Standard substance: Polyethylene glycol (Mn = 2,000,000, 200,000, 20,000, 2,000, 200)
Detector: Differential refractometer detector (Shodex RI-201H)

(4) Analysis of organic shrinkage proofing agent (4-1) Qualitative analysis of organic shrinkage proofing agent in negative electrode material The crushed sample A is immersed in a 1 mol / L sodium hydroxide aqueous solution to extract the organic shrinkage proofing agent. Next, the first organic shrinkage proofing agent and the second organic shrinkage proofing agent are separated from the extract, if necessary. For each of the isolates containing each organic shrinkant, the insoluble components are filtered off, the resulting solution is desalted, then concentrated and dried. Desalination is performed using a desalting column, by passing the solution through an ion exchange membrane, or by placing the solution in a dialysis tube and immersing it in distilled water. By drying this, a powder sample of an organic shrinkage proofing agent (hereinafter referred to as sample B) can be obtained.

The infrared spectroscopic spectrum measured using the sample B of the organic shrinkage proofing agent thus obtained, the ultraviolet visible absorption spectrum measured by diluting the sample B with distilled water or the like, and the sample B being used as heavy water or the like. Combining the NMR spectrum of the solution obtained by dissolving in a predetermined solvent or the information obtained from thermal decomposition GC-MS or the like capable of obtaining information on the individual compounds constituting the substance, the organic shrinkage proofing agent Identify the type.

The separation of the first organic shrinkage proofing agent and the second organic shrinkage proofing agent from the above extract is carried out as follows. First, the extract is measured by infrared spectroscopy, NMR, and / or GC-MS to determine whether or not it contains a plurality of organic shrink proofing agents. Next, the molecular weight distribution is measured by GPC analysis of the extract, and if a plurality of organic shrink-proofing agents can be separated by molecular weight, the organic shrinkage-proofing agents are separated by column chromatography based on the difference in molecular weight. When separation due to the difference in molecular weight is difficult, one of the organic shrinkage proofing agents is separated by a precipitation separation method by utilizing the difference in solubility which differs depending on the type of functional group and / or the amount of functional groups of the organic shrinkage proofing agent. Specifically, one of the organic shrink-proofing agents is aggregated and separated by adding a sulfuric acid aqueous solution to a mixture in which the above extract is dissolved in a NaOH aqueous solution and adjusting the pH of the mixture. As described above, the insoluble component is removed by filtration from the solution in which the separated product is dissolved again in the aqueous NaOH solution. Also, the remaining solution after separating one of the organic shrink proofing agents is concentrated. The obtained concentrate contains the other organic shrink-proofing agent, and the insoluble component is removed from the concentrate by filtration as described above.

(4-2) Quantification of the content of the organic shrinkage proofing agent in the negative electrode electrode material In the same manner as in (4-1) above, a solution is obtained after removing insoluble components from each of the separated substances containing the organic shrinkage proofing agent by filtration. .. The ultraviolet-visible absorption spectrum is measured for each of the obtained solutions. The content of each organic shrinkage proofing agent in the negative electrode electrode material is determined by using the peak intensity characteristic of each organic shrinkage proofing agent and the calibration curve prepared in advance.

When a lead-acid battery having an unknown content of the organic shrinkage proof is obtained and the content of the organic shrinkage proofing agent is measured, the structural formula of the organic shrinkage proofing agent cannot be specified exactly, so that the same organic shrinkage proofing is applied to the calibration curve. The agent may not be available. In this case, calibration is performed using an organic shrink-proofing agent extracted from the negative electrode of the battery and a separately available organic polymer having a similar shape in the ultraviolet-visible absorption spectrum, infrared spectroscopic spectrum, NMR spectrum, and the like. By creating a line, the content of the organic shrink-proofing agent shall be measured using the ultraviolet-visible absorption spectrum.

(4-3) Sulfur element content in the organic shrinkage proofing agent In the same manner as in (4-1) above, after obtaining the sample B of the organic shrinkage proofing agent, 0.1 g of the organic shrinkage proofing agent is added by the oxygen combustion flask method. Converts the sulfur element of the to sulfuric acid. At this time, by burning the sample B in the flask containing the adsorbent, an eluate in which sulfate ions are dissolved in the adsorbent is obtained. Next, the content (c1) of the sulfur element in 0.1 g of the organic shrink-proofing agent is determined by titrating the eluate with barium perchlorate using thorin as an indicator. Next, c1 is multiplied by 10 to calculate the content of sulfur element (μmol / g) in the organic shrinkage proofing agent per 1 g.

(4-4) Mw measurement of organic shrink-proofing agent In the same manner as in (4-1) above, after obtaining sample B of the organic shrinkage-proofing agent, GPC measurement of the organic shrinkage-proofing agent is performed using the following device under the following conditions. conduct. Separately, a calibration curve (calibration curve) is created from the plot of Mw of the standard substance and the elution time. Based on this calibration curve and the GPC measurement result of the organic shrinkage proofing agent, Mw of the organic shrinkage proofing agent is calculated.

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 ID x 30 cm) (manufactured by Tosoh Corporation)
Detector: UV detector, λ = 210nm
Eluent: A mixed solution of NaCl aqueous solution with a concentration of 1 mol / L: acetonitrile (volume ratio = 7: 3) Flow velocity: 1 mL / min.
Concentration: 10 mg / mL
Injection volume: 10 μL
Standard substance: Na polystyrene sulfonate (Mw = 275,000, 35,000, 12,500, 7,500, 5,200, 1,680)

(others)
The negative electrode plate can be formed by applying or filling a negative electrode paste to a negative electrode current collector, aging and drying to produce an unchemical negative electrode plate, and then forming an unchemical negative electrode plate. The negative electrode paste is, for example, water, for example, at least one selected from the group consisting of lead powder, an organic shrink-proofing agent (B), and optionally a polymer compound (P), a carbonaceous material, and other additives. And sulfuric acid (or aqueous sulfuric acid solution) are added and kneaded to prepare the mixture. At the time of aging, it is preferable to ripen the unchemical negative electrode plate at a temperature higher than room temperature and high humidity.

The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group. The formation produces spongy lead.

(Positive plate)
The positive electrode plate of a lead storage battery can be classified into a paste type, a clad type and the like. Either a paste type or a clad type positive electrode plate may be used. The paste type positive electrode plate includes a positive electrode current collector and a positive electrode material. The configuration of the clad type positive electrode plate is as described above.

The positive electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding processing and punching processing. It is preferable to use a grid-shaped current collector as the positive electrode current collector because it is easy to support the positive electrode material.

As the lead alloy used for the positive electrode current collector, Pb-Sb-based alloys, Pb-Ca-based alloys, and Pb-Ca-Sn-based alloys are preferable in terms of corrosion resistance and mechanical strength. The positive electrode current collector may include a surface layer. The composition of the surface layer and the inner layer of the positive electrode current collector may be different. The surface layer may be formed on a part of the positive electrode current collector. The surface layer may be formed only on the lattice portion of the positive electrode current collector, only the ear portion, or only the frame bone portion.

The positive electrode material contained in the positive electrode plate contains a positive electrode active material (lead dioxide or lead sulfate) whose capacity is developed by a redox reaction. The positive electrode material may contain other additives, if necessary.

The unchemical paste type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste, aging and drying. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid. The unchemical clad type positive electrode plate is formed by filling a porous tube into which a core metal connected at a current collecting part is inserted with lead powder or slurry-like lead powder, and connecting a plurality of tubes in a collective punishment. Will be done. Then, a positive electrode plate is obtained by forming these unchemical positive electrode plates. The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical positive electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group.

The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical positive electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group.

(Separator)
A separator can be arranged between the negative electrode plate and the positive electrode plate. As the separator, at least one selected from a non-woven fabric and a microporous membrane is used.

Nonwoven fabric is a mat that is entwined without weaving fibers, and is mainly composed of fibers. In the non-woven fabric, for example, 60% by mass or more of the non-woven fabric is formed of fibers. As the fiber, glass fiber, polymer fiber (polyolefin fiber, acrylic fiber, polyester fiber (polyethylene terephthalate fiber, etc.), etc.), pulp fiber, and the like can be used. Of these, glass fiber is preferable. The non-woven fabric may contain components other than fibers, such as an acid-resistant inorganic powder, a polymer as a binder, and the like.

On the other hand, the microporous film is a porous sheet mainly composed of components other than fiber components. For example, a composition containing a pore-forming agent is extruded into a sheet and then the pore-forming agent is removed to form pores. It is obtained by. The microporous membrane is preferably composed of a material having acid resistance, and is preferably composed mainly of a polymer component. As the polymer component, polyolefin (polyethylene, polypropylene, etc.) is preferable. Examples of the pore-forming agent include at least one selected from the group consisting of polymer powders and oils.

The separator may be composed of, for example, only a non-woven fabric or only a microporous membrane. Further, the separator may be a laminate of a non-woven fabric and a microporous film, a material obtained by laminating different or similar materials, or a material in which irregularities are engaged with different or similar materials, as required.

The separator may be in the shape of a sheet or in the shape of a bag. A sheet-shaped separator may be sandwiched between the positive electrode plate and the negative electrode plate. Further, the electrode plate may be arranged so as to sandwich the electrode plate with one sheet-shaped separator in a bent state. In this case, the positive electrode plate sandwiched between the bent sheet-shaped separators and the negative electrode plate sandwiched between the bent sheet-shaped separators may be overlapped, and one of the positive electrode plate and the negative electrode plate may be sandwiched between the bent sheet-shaped separators. , May be overlapped with the other electrode plate. Further, the sheet-shaped separator may be bent in a bellows shape, and the positive electrode plate and the negative electrode plate may be sandwiched between the bellows-shaped separators so that the separator is interposed between them. When a bag-shaped separator is used, the bag-shaped separator may accommodate a positive electrode plate or a negative electrode plate.

(Electrolytic solution)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The electrolytic solution may contain the above-mentioned polymer compound (P).

The electrolyte may optionally contain cations (eg, metal cations) and / or anions (eg, anions other than sulfate anions (such as phosphate ions)). Examples of the metal cation include at least one selected from the group consisting of Na ion, Li ion, Mg ion, and Al ion.

The specific gravity of the electrolytic solution in the fully charged lead storage battery at 20 ° C. is, for example, 1.20 or more, and may be 1.25 or more. The specific gravity of the electrolytic solution at 20 ° C. is 1.35 or less, preferably 1.32 or less.

The specific gravity of the electrolytic solution at 20 ° C. may be 1.20 or more and 1.35 or less, 1.20 or more and 1.32 or less, 1.25 or more and 1.35 or less, or 1.25 or more and 1.32 or less. ..

(others)
The lead-acid battery can be obtained by a manufacturing method including a step of accommodating a group of plates and an electrolytic solution in a cell chamber of an electric tank. Each cell of the lead-acid battery includes a group of plates and an electrolytic solution housed in each cell chamber. The electrode plate group is assembled by laminating the positive electrode plate, the negative electrode plate, and the separator so that the separator is interposed between the positive electrode plate and the negative electrode plate prior to the accommodation in the cell chamber. The positive electrode plate, the negative electrode plate, the electrolytic solution, and the separator are each prepared prior to assembling the electrode plate group. The method for manufacturing a lead-acid battery may include, if necessary, a step of forming at least one of a positive electrode plate and a negative electrode plate after a step of accommodating a group of electrode plates and an electrolytic solution in a cell chamber.

Each plate in the plate group may be one plate or two or more plates.

An example of a lead storage battery according to an embodiment of the present invention will be described below with reference to the drawings. The above description can be applied to the embodiments described below. Further, the embodiments described below may be modified based on the above description. Further, the matters described below may be applied to the above-described embodiment. Further, among the items described below, items that are not essential to the present invention may be omitted.

FIG. 1 shows the appearance of an example of a lead storage battery according to an embodiment of the present invention. The lead-acid battery 1 includes an electric tank 12 for accommodating a plate group 11 and an electrolytic solution (not shown). The inside of the electric tank 12 is partitioned into a plurality of cell chambers 14 by a partition wall 13. One electrode plate group 11 is housed in each cell chamber 14. The opening of the battery case 12 is closed by a lid 15 including a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a liquid spout 18 for each cell chamber. At the time of refilling water, the liquid spout 18 is removed and the refilling liquid is replenished. The liquid spout 18 may have a function of discharging the gas generated in the cell chamber 14 to the outside of the battery.

The electrode plate group 11 is configured by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via a separator 4, respectively. Here, the bag-shaped separator 4 accommodating the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. In the cell chamber 14 located at one end of the battery case 12, the negative electrode shelf portion 6 for connecting the plurality of negative electrode plates 2 in parallel is connected to the through connection body 8, and the positive electrode shelf portion for connecting the plurality of positive electrode plates 3 in parallel is connected. 5 is connected to the positive electrode column 7. The positive electrode column 7 is connected to the positive electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative electrode column 9 is connected to the negative electrode shelf portion 6, and the penetration connecting body 8 is connected to the positive electrode shelf portion 5. The negative electrode column 9 is connected to the negative electrode terminal 16 outside the lid 15. Each through-connecting body 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plates 11 of the adjacent cell chambers 14 in series.

The positive electrode shelf portion 5 is formed by welding the selvage portions provided on the upper portions of the positive electrode plates 3 to each other by a cast-on-strap method or a burning method. The negative electrode shelf portion 6 is also formed by welding the selvage portions provided on the upper portions of the negative electrode plates 2 as in the case of the positive electrode shelf portion 5.

The lid 15 of the lead storage battery has a single structure (single lid), but is not limited to the case shown in the illustrated example. The lid 15 may have, for example, a double structure including an inner lid and an outer lid (or upper lid). The lid having a double structure is provided with a recirculation structure between the inner lid and the outer lid for returning the electrolytic solution to the inside of the battery (inside the inner lid) from the recirculation port provided in the inner lid. May be good.

The lead-acid batteries according to one aspect of the present invention are summarized below.

(1) A lead-acid battery containing a negative electrode containing a negative electrode material and a positive electrode.
The negative electrode material contains an organic shrinkage proofing agent and barium sulfate.
The organic shrinkage proofing agent is a condensate containing a bisphenol unit and is a condensate.
The surface area of the barium sulfate is 0.04 m2 or more per 1 g of the negative electrode material.

(2) In the above (1), the average particle size of the barium sulfate may be 0.5 μm or more and 1.0 μm or less.

(3) In the above (1) or (2), the content of the barium sulfate in the negative electrode electrode material may be 0.9% by mass or more.

(4) In any one of the above (1) to (3), the organic shrinkage proofing agent may be a condensate containing a bisphenol S unit and a bisphenol A unit.

(5) In any one of the above (1) to (4), the negative electrode electrode material may further contain a polymer compound other than the organic shrinkage proofing agent, and the content of the polymer compound in the negative electrode electrode material. May be in the range of 100 ppm to 1000 ppm on a mass basis, and the polymer compound is 3.2 ppm or more and 3.8 ppm or less in the chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent. It may have a peak in the range.

(6) In any one of the above (1) to (4), the negative electrode material may further contain a polymer compound other than the organic shrinkage proofing agent, and the content of the polymer compound in the negative electrode material. May be in the range of 100 ppm to 1000 ppm on a mass basis, and the polymer compound may contain an oxyC _2-4 alkylene unit as a repeating structure.

[Example]
Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<< Lead-acid batteries A1 to A10, C1 to C6 >>
(1) Preparation of lead-acid battery (a) Preparation of negative electrode plate A suitable amount of sulfuric acid aqueous solution of lead powder as a raw material, barium sulfate particles, carbon black, an organic shrinkage proofing agent, and a polymer compound (P) as needed. To obtain a negative paste. Next, the negative electrode paste is filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy and aged and dried to obtain an unchemical negative electrode plate.

In the production of the negative electrode plates of the batteries C1 to C5, sodium lignin sulfonate (lignin compound) is used as the organic shrinkage proofing agent. In the production of the negative electrode plates of the batteries C6 and A1 to A10, the organic shrinkage proofing agent (B) is used as the organic shrinkage proofing agent. Specifically, a formaldehyde-based condensate of a bisphenol compound having a sulfonic acid group introduced is used. Polypropylene glycol (number average molecular weight of about 2000) is used as the polymer compound (P). In the production of the negative electrode plates of the batteries C1 to C5, sodium lignin sulfonate is added to the negative electrode paste so that the content of sodium lignin sulfonate in the negative electrode electrode material is 0.33% by mass. In the production of the negative electrode plates of the batteries C6 and A1 to A10, the organic shrinkage proofing agent (B) is added to the negative electrode paste so that the content of the organic shrinkage proofing agent (B) in the negative electrode electrode material is 0.13% by mass. .. The barium sulfate particles and the polymer compound (P) are added to the negative electrode paste so that the content in the negative electrode electrode material is the content shown in Table 1. Further, in the production of each negative electrode plate, carbon black is added to the negative electrode paste so that the content of carbon black in the negative electrode electrode material is 0.9% by mass. The average particle size of barium sulfate is changed by using commercially available barium sulfate particles having different average particle sizes. By changing the amount of barium sulfate particles added to the negative electrode paste and / or the specific surface area of the particles, the surface area (Z) of barium sulfate per 1 g of the negative electrode material can be changed.

(B) Preparation of positive electrode plate The lead powder as a raw material is mixed with an aqueous sulfuric acid solution to obtain a positive electrode paste. The positive electrode paste is filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy and aged and dried to obtain an unchemicald positive electrode plate.

(C) Preparation of test battery The test battery has a rated voltage of 2 V / cell and a rated 5-hour rate capacity of 32 Ah. The electrode plate group of the test battery is composed of seven positive electrode plates and seven negative electrode plates. The negative electrode plate is housed in a bag-shaped separator formed of a microporous polyethylene film, and is alternately laminated with the positive electrode plate to form a group of electrode plates. A group of electrode plates is housed in a polypropylene electric tank together with an electrolytic solution (sulfuric acid aqueous solution) and chemically formed in the electric tank to produce a liquid-type lead-acid battery. The specific gravity of the electrolytic solution in a fully charged lead-acid battery at 20 ° C. is 1.28.

(2) Evaluation (a) Evaluation of charge acceptance performance A predetermined integrated electric energy is measured using a fully charged test battery. Specifically, the test battery is discharged at 6.4 A for 30 minutes and left for 16 hours. After that, the test battery is charged with a constant current and constant voltage at 2.42 V / cell (current upper limit: 200 A). At this time, the integrated electric energy for 10 seconds from the start of charging is measured. Both operations are performed in a water tank at 25 ° C ± 2 ° C. The charge acceptance performance of each lead-acid battery is evaluated by the ratio of the integrated electric power of each battery when the integrated electric power of the lead-acid battery C1 is 100%.

(B) Evaluation of high rate discharge performance at low temperature after light load test A high temperature light load test is performed under the following conditions using the above lead-acid battery. Specifically, in order to make the overcharge condition more than the normal 4-minute-10-minute test specified in JIS D5301, it is composed of 1-minute discharge and 10-minute charge under the following conditions. A charge / discharge cycle (1 minute-10 minute test) is performed at 75 ° C. A high-temperature light load test in which this charge / discharge cycle is repeated 1220 cycles is performed using the lead-acid battery.
Discharge: 25A, 1 minute Charge: 2.47V / cell, 25A, 10 minutes Water tank temperature: 75 ° C

The fully charged test battery after the high temperature light load test is discharged at −15 ° C. with a discharge current of 150 A until the terminal voltage reaches 1.0 V / cell. Then, the discharge time (s) at this time is used to evaluate the high rate discharge performance at a low temperature after the light load test. The longer the discharge time, the better the low temperature and high rate discharge performance. The low temperature and high rate discharge performance of each battery is evaluated by the ratio (%) when the discharge time of the lead storage battery C1 is 100.

Table 1 shows some of the manufacturing conditions and evaluation results. In Table 1, the surface area (Z) of barium sulfate is the surface area per 1 g of the negative electrode material. The content of barium sulfate and the content of the polymer compound (P) are mass-based contents in the negative electrode material.

The higher the numerical value, the more preferable the low temperature and high rate discharge performance and the charge acceptance performance in Table 1. The low temperature and high rate discharge performance in Table 1 is preferably 100% or more, more preferably 105% or more, still more preferably 110% or more, and particularly preferably 115% or more. Is more preferable, and 115% or more is further preferable. The charge acceptance performance in Table 1 is preferably 102% or more, more preferably 105% or more, still more preferably 110% or more, and particularly preferably 115% or more (for example, 120% or more). Batteries having a low temperature and high rate discharge performance of 100% or more and a charge acceptance performance of 102% or more are preferable.

As shown in Table 1, the batteries A1 to A10 in which the organic shrinkage proofing agent (B) is used and the average particle size of barium sulfate is 0.04 μm or more (for example, 0.05 μm or more) are the batteries C1 to C6. Unlike, it can achieve both high low temperature and high rate discharge performance and high charge acceptance performance.

As shown in Table 1, all of the batteries A4 to A6 in which the polymer compound (P) was added to the negative electrode electrode material showed high low temperature and high rate discharge performance and high charge acceptance performance.

The evaluation results of the low-temperature high-rate discharge performance and the charge acceptance performance of the batteries C1 to C4 and the batteries C6 and A1 to A3 are shown in FIGS. 2 and 3, respectively. The organic condensate of the batteries C1 to C4 is a lignin compound. The organic condensate of the batteries C6 and A1 to A3 is the organic condensate (B).

As shown in FIG. 2, as the surface area (Z) of barium sulfate increases, the high rate discharge performance improves. This improvement is gradual in batteries using a lignin compound as an organic shrinkage proofing agent. On the other hand, in the battery using the organic shrinkage proofing agent (B) as the organic shrinkage proofing agent, the surface area (Z) of barium sulfate is larger than 0.02 m ² / g (for example, 0.04 m ² / g or more or 0.05 m ² / g). Above), the high rate discharge performance rises sharply.

As shown in FIG. 3, in a battery using a lignin compound as an organic shrinkage proofing agent, the charge acceptance performance slightly deteriorates as the surface area (Z) of barium sulfate increases. On the other hand, in the battery using the organic shrinkage proofing agent (B) as the organic shrinkage proofing agent, the charge acceptance performance is improved as the surface area (Z) of barium sulfate increases. In the battery using the organic shrink proofing agent (B), the charge acceptance performance is in a region where the surface area (Z) of barium sulfate is larger than 0.02 m ² / g (for example, 0.04 m ² / g or more or 0.05 m ² / g or more). Will rise significantly.

The reason for obtaining the above results is not clear at present, but it can be considered as follows. When the surface of barium sulfate is coated with an organic shrink-proofing agent, the effect of adding barium sulfate is reduced. From various studies, it was found that the area where the organic shrink-proofing agent (B) covers the negative electrode active material or the additive may be larger than the area where the same amount of the lignin compound covers the negative electrode active material or the additive. rice field. Therefore, when the organic shrinkage proofing agent (B) is used as the organic shrinkage proofing agent, it is considered necessary to add barium sulfate to the negative electrode electrode material so as to have a surface area (Z) of a predetermined value or more.

The average particle size of barium sulfate is also important in order to enhance the effect of setting the surface area (Z) of barium sulfate to a predetermined value or more. By reducing the average particle size of barium sulfate, the required amount of addition can be reduced. On the contrary, by increasing the average particle size of barium sulfate, it becomes easy to avoid the problem that barium sulfate closes the pores of the negative electrode electrode material and the problem that the negative electrode active materials are difficult to bind to each other. Therefore, it is preferable that the average particle size of barium sulfate is within a predetermined range.

The present invention can be used for lead storage batteries. The lead-acid battery of the present invention is suitable for use in an idling stop vehicle as, for example, a lead-acid battery for IS that is charged and discharged under PSOC conditions. Further, the lead-acid battery can be suitably used, for example, as a power source for starting a vehicle (automobile, motorcycle, etc.) or an industrial power storage device (for example, a power source for an electric vehicle (forklift, etc.)). It should be noted that these uses are merely examples and are not limited to these uses.

1: Lead-acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 5: Positive electrode shelf part 6: Negative electrode shelf part 7: Positive electrode pillar 8: Through connection body 9: Negative electrode pillar 11: Electrode plate group 12: Electric tank 13: Bulk partition 14: Cell chamber 15: Lid 16: Negative electrode terminal 17: Positive electrode terminal 18: Liquid spout

Claims (6)

A lead-acid battery containing a negative electrode containing a negative electrode material and a positive electrode.
The negative electrode material contains an organic shrinkage proofing agent and barium sulfate.
The organic shrinkage proofing agent is a condensate containing a bisphenol unit and is a condensate.
A lead-acid battery having a surface area of barium sulfate of 0.04 m ² or more per 1 g of the negative electrode material. The lead-acid battery according to claim 1, wherein the barium sulfate has an average particle size of 0.5 μm or more and 1.0 μm or less. The lead-acid battery according to claim 1 or 2, wherein the content of the barium sulfate in the negative electrode electrode material is 0.9% by mass or more. The lead-acid battery according to any one of claims 1 to 3, wherein the organic shrinkage proofing agent is a condensate containing a bisphenol S unit and a bisphenol A unit. The negative electrode material further contains a polymer compound other than the organic shrinkage proofing agent, and the negative electrode material further contains.
The content of the polymer compound in the negative electrode material is in the range of 100 ppm to 1000 ppm on a mass basis.
One of claims 1 to 4, wherein the polymer compound has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent. Lead-acid battery described in. The negative electrode material further contains a polymer compound other than the organic shrinkage proofing agent, and the negative electrode material further contains.
The content of the polymer compound in the negative electrode material is in the range of 100 ppm to 1000 ppm on a mass basis.
The lead-acid battery according to any one of claims 1 to 4, wherein the polymer compound contains an oxyC _2-4 alkylene unit as a repeating structure.

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