Lead-acid battery

Abstract

This lead-acid battery of control valve type comprises at least one cell including an electrode plate group and an electrolytic solution. The electrode plate group is provided with: a negative electrode plate; a positive electrode plate; and a separator that is interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate comprises a negative electrode material. The negative electrode material contains a polymer compound having a peak in the range of 3.2-3.8 ppm in a chemical shift in a 1H-NMR spectrum that is measured using deuterated chloroform as a solvent. The positive electrode plate comprises a positive electrode material. The density of the positive electrode material is 3.70-4.65 g / cm3 <sp / >.

Description

Technical Field

[0001] The present invention relates to a lead storage battery.

Background Art

[0002] Lead storage batteries are used in various applications, including in-vehicle and industrial applications. A lead storage battery includes a negative electrode plate, a positive electrode plate, a separator (or mat), and an electrolyte solution. Each electrode plate includes a current collector and an electrode material.

[0003] There are liquid-type lead storage batteries and control valve-type lead storage batteries. A liquid-type lead storage battery is an open-type lead storage battery including a battery case, and a group of electrode plates and an electrolyte solution housed in the battery case. On the other hand, a control valve-type lead storage battery is a sealed-type lead storage battery including a group of electrode plates including a positive electrode plate, a negative electrode plate, and a fine glass mat separator (retainer mat) interposed between the positive electrode plate and the negative electrode plate, and an electrolyte solution. In the control valve-type lead storage battery, the electrolyte solution is held by the separator, and the oxygen gas generated at the positive electrode plate is reduced to water at the negative electrode plate, utilizing a principle called the so-called oxygen cycle.

[0004] From the viewpoint of imparting various functions to the lead storage battery, an additive may be added to the constituent members of the lead storage battery.

[0005] Patent Document 1 proposes a lead storage battery characterized by containing, in an electrolyte solution and / or an electrode active material molded body, any one of a polymer compound including any one of polyvinyl alcohol having a polymerization degree of 30 or more and 3000 or less, polyethylene glycol, polyvinyl pyrrolidone, polyacrylic acid, or an ester thereof, or any one of the polymer compound and colloidal barium sulfate particles.

[0006] It has also been proposed to adjust the density of the electrode material and the like.

[0007] Patent Document 2 discloses a lead-acid battery characterized in that a positive electrode plate holding a positive electrode active material containing barium is formed, the positive electrode plate after formation contains barium at an average value of 10 ppm or more and 1000 ppm or less per sheet, and the active material density of the electrode plate after formation is 3.1 g / cc or more and 4.2 g / cc or less at an average value per sheet. When the barium content is X and the active material density is Y, -0.29 log X + 3.6 ≤ Y ≤ -0.29 log X + 4.7 is satisfied.

Prior Art Documents

Patent Documents

[0008]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0009] In a lead-acid battery, when self-discharge occurs, lead sulfate is generated. The lead sulfate generated by self-discharge is difficult to be reduced during charging. When the accumulation of lead sulfate becomes significant, sulfation occurs in which the accumulated lead sulfate becomes inactivated, resulting in a decrease in life performance. Therefore, in a lead-acid battery, it is required to suppress self-discharge. Further, in a valve-regulated lead-acid battery, since the amount of electrolyte is small with respect to the active material, when self-discharge progresses, the specific gravity of the electrolyte decreases, which easily leads to a voltage drop.

Means for Solving the Problems

[0010] In view of the above, a first aspect of the present invention is a valve-regulated lead-acid battery, the lead-acid battery includes at least one cell including a group of electrode plates and an electrolyte, the group of electrode plates includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate includes a negative electrode material, The negative electrode material is measured using deuterated chloroform as a solvent 1 and includes a polymer compound having a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1H-NMR spectrum. The positive electrode plate includes a positive electrode material, The density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm 3 or less, relating to a lead-acid battery.

[0011] A second aspect of the present invention is a controlled valve type lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte, The plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate includes a negative electrode material, The negative electrode material includes a polymer compound including a repeating structure of oxy C 2-4 alkylene units, The positive electrode plate includes a positive electrode material, The density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm 3 or less, relating to a lead-acid battery.

Brief Description of the Drawings

[0012]

Figure 1

Mode for Carrying Out the Invention

[0013] In a lead-acid battery, since the self-discharge reaction proceeds relatively slowly, the lead sulfate generated during self-discharge on the negative electrode plate tends to have its crystal structure grow and become dense. Such lead sulfate has low activity and is difficult to be reduced during charging. Therefore, even if the lead-acid battery is charged after self-discharge, it is likely to remain in a state where lead sulfate accumulates. In such a state, when the lead-acid battery is repeatedly charged and discharged, the accumulation of lead sulfate progresses, sulfation occurs, and the life performance of the lead-acid battery deteriorates. For example, in small mobility such as motorcycles, there may be a period of non-use depending on the season, so self-discharge of the installed lead-acid battery tends to progress.

[0014] In view of the above, the lead-acid battery according to the first aspect of the present invention is a controlled valve type lead-acid battery, and includes at least one cell including a plate group and an electrolyte. The plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate includes a negative electrode material. The negative electrode material includes a polymer compound having a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1H-NMR spectrum measured using deuterated chloroform as a solvent. The positive electrode plate includes a positive electrode material. The density of the positive electrode material is 3.70 g / cm 1 or more and 4.65 g / cm 3 or less. 3 In addition, in the above-mentioned 1H-NMR spectrum, the peak appearing in the chemical shift range of 3.2 ppm or more and 3.8 ppm or less is derived from an oxy-C 1 alkylene unit. 2-4

[0015] The lead-acid battery according to the second aspect of the present invention is a controlled valve type lead-acid battery, and includes at least one cell including a plate group and an electrolyte. The plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate includes a negative electrode material. The negative electrode material includes a polymer compound including a repeating structure of an oxy-C 2-4 alkylene unit. The positive electrode plate includes a positive electrode material. The density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm3 It is as follows.

[0016] In the lead-acid battery according to each of the first aspect and the second aspect of the present invention, the negative electrode material contains the polymer compound as described above, and the density of the positive electrode material is controlled within the above specific range. With such a configuration, the self-discharge of the lead-acid battery can be significantly reduced. By reducing the self-discharge, it is advantageous for the lead-acid battery to have a long life.

[0017] In each of the lead-acid batteries according to the first aspect and the second aspect of the present invention, it is considered that the self-discharge is reduced for the following reasons.

[0018] First, by making the density of the positive electrode material higher than 3.70 g / cm 3 ³, the size of the pores in the positive electrode material becomes smaller, and it becomes difficult for the electrolyte to penetrate into the inside of the positive electrode material. As a result, since the discharge reaction itself is reduced, the self-discharge reaction is also reduced. In a general regulated valve type lead-acid battery, the density of the positive electrode material is about 3.66 g / cm 3 ³.

[0019] Next, in the lead-acid batteries according to the first aspect and the second aspect of the present invention, since the density of the positive electrode material is large and the self-discharge reaction is reduced, the amount of oxygen gas generated from the positive electrode plate is reduced. In the negative electrode plate, when oxygen gas is absorbed and water is generated, a side reaction in which PbO is generated from Pb occurs. PbO reacts with the electrolyte to generate lead sulfate. However, since the amount of oxygen gas generated from the positive electrode plate is reduced, the amount of PbO generated also decreases, so the reaction in which lead sulfate is generated is also reduced. As a result, the self-discharge is reduced.

[0020] Furthermore, since the polymer compound contained in the negative electrode material is likely to have a linear structure by having a repeating structure of oxy C 2-4 alkylene units, the surface of lead in the negative electrode material is thinly and widely covered with the polymer compound. As a result, the oxygen gas absorption reaction itself in the negative electrode plate is reduced, so the self-discharge is reduced.

[0021] In this way, due to the mutual correlation of multiple factors, self-discharge is significantly reduced. Therefore, self-discharge can also be synergistically reduced.

[0022] The effect of the polymer compound on the negative electrode material as described above is exerted by the polymer compound covering the surface of lead. Therefore, it is important to have the polymer compound in the vicinity of lead, and thereby the effect of the polymer compound can be effectively exerted. Thus, regardless of whether the polymer compound is contained in the components of the lead storage battery other than the negative electrode material, it is important that the negative electrode material contains the polymer compound.

[0023] In the lead storage battery according to the first aspect of the present invention, the polymer compound may include an oxygen atom bonded to a terminal group, and a -CH 2 - group and / or a -CH< group bonded to the oxygen atom. 1 In the 1H-NMR spectrum, the ratio of the integral value of the peak in the range of 3.2 ppm to 3.8 ppm to the total of the integral value of the peak of the hydrogen atom of the -CH 2 - group bonded to the oxygen atom and the integral value of the peak of the hydrogen atom of the -CH< group bonded to the oxygen atom is preferably 85% or more. Such a polymer compound contains many oxyC 2-4 alkylene units in the molecule. Therefore, it is considered that the polymer compound is likely to adsorb to lead and is more likely to take a linear structure, making it easier to thinly cover the lead surface. Thus, the oxygen gas absorption reaction in the negative electrode plate is further reduced, and self-discharge can be more effectively reduced.

[0024] 1 In the 1H-NMR spectrum, the polymer compound having a peak in the chemical shift range of 3.2 ppm to 3.8 ppm preferably contains a repeating structure of oxyC 2-4 alkylene units. OxyC 2-4When using a polymer compound containing a repeating structure of alkylene units, it is considered that the polymer compound is more likely to adsorb to lead and is more likely to form a linear structure, making it easier to thinly cover the lead surface. Therefore, the oxygen gas absorption reaction in the negative electrode plate is further reduced, and self-discharge can be more effectively reduced.

[0025] The polymer compound is oxy C 2-4 It may contain at least one selected from the group consisting of a hydroxy compound having a repeating structure of alkylene units, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound. Here, the hydroxy compound is poly C 2-4 Alkylene glycol, oxy C 2-4 A copolymer containing a repeating structure of alkylene, and poly C of polyol 2-4 It is at least one selected from the group consisting of alkylene oxide adducts. When using such a polymer compound, it is considered that the polymer compound is more likely to adsorb to lead and is more likely to form a linear structure, making it easier to thinly cover the lead surface. Therefore, the oxygen gas absorption reaction in the negative electrode plate is further reduced, and self-discharge can be more effectively reduced.

[0026] The polymer compound may contain a repeating structure of oxypropylene units (-O-CH(-CH 3 )-CH 2 -). When the negative electrode material contains such a polymer compound, compared with the case of containing a repeating structure of oxyethylene units (-O-CH 2 -CH 2 -), when the density of the positive electrode material is 3.70 g / cm 3 or more, self-discharge is more likely to increase. In each of the first aspect and the second aspect, even when the negative electrode material contains a polymer compound containing a repeating structure of oxypropylene units, self-discharge can be suppressed low by controlling the density of the positive electrode material.

[0027] The polymer compound has one or more hydrophobic groups, and at least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. Due to the action of such hydrophobic groups, excessive coating of the polymer compound on the lead surface is suppressed, and uneven distribution of the polymer compound is suppressed. The polymer compound preferably contains a repeating structure of oxyethylene units. By including a repeating structure of oxyethylene units in which the polymer compound has high hydrophilicity, the polymer compound can be selectively adsorbed onto lead. Due to the balance between the hydrophobic group and the hydrophilic group, while ensuring high adsorptivity to lead, uneven distribution of the polymer compound is suppressed, so that self-discharge can be further reduced and high low-temperature high-rate (HR) discharge performance can be ensured.

[0028] Thus, although the polymer compound has high adsorptivity to lead, it can thinly cover the lead surface. Therefore, even if the content of the polymer compound in the negative electrode material is small, self-discharge can be reduced. From the viewpoint of further reducing self-discharge, the content of the polymer compound in the negative electrode material is preferably 10 ppm or more on a mass basis. From the viewpoint of ensuring higher low-temperature HR discharge performance, the content of the polymer compound in the negative electrode material is preferably 370 ppm or less on a mass basis.

[0029] In a lead storage battery, it is only necessary to be able to contain the polymer compound in the negative electrode material, and the origin of the polymer compound contained in the negative electrode material is not particularly limited. The polymer compound may be contained in any of the components of the lead storage battery (for example, the negative electrode plate, the positive electrode plate, the electrolyte, and the separator) when manufacturing the lead storage battery. The polymer compound may be contained in one component, or may be contained in two or more components (for example, the negative electrode plate and the electrolyte).

[0030] The negative electrode material may include a condensate of a bisarene compound. The condensate of the bisarene compound is generally classified as a synthetic organic shrinkage inhibitor. Generally, when the negative electrode material contains a condensate of a bisarene compound, the specific surface area of the negative electrode material increases, and thus the hydrogen overvoltage tends to decrease. However, in the lead-acid battery according to the first aspect and the second aspect of the present invention, since the negative electrode material contains a polymer compound and the density of the positive electrode material is controlled within a specific range, even when the organic shrinkage inhibitor contains a condensate of a bisarene compound, the hydrogen overvoltage can be increased and self-discharge can be suppressed at a low level. Also, when the negative electrode material contains a lignin compound, self-discharge can be suppressed at a low level.

[0031] The negative electrode material may include a carbonaceous material. The content of the carbonaceous material in the negative electrode material is preferably 0.1% by mass or more. In this case, due to the decrease in the hydrogen overvoltage, self-discharge tends to increase. However, even in such a case, by including a polymer compound in the negative electrode material and controlling the density of the positive electrode material, self-discharge can be suppressed at a low level. From the viewpoint of further enhancing the effect of reducing self-discharge due to the easy adsorption of the polymer compound to lead, the content of the carbonaceous material in the negative electrode material is preferably 1.2% by mass or less.

[0032] In small mobility applications, as described above, self-discharge tends to progress during periods when it is not in use. Therefore, each of the lead-acid batteries according to the first aspect and the second aspect is suitable for small mobility applications. However, the applications of lead-acid batteries are not limited to small mobility applications.

[0033] A lead-acid battery with a control valve is sometimes called a sealed lead-acid battery (or VRLA type lead-acid battery).

[0034] In this specification, the content of the polymer compound in the negative electrode material and the density of the positive electrode material are determined for the negative electrode plate or the positive electrode plate taken out from a fully charged lead-acid battery.

[0035] (Explanation of Terms) (Electrode Material) Each of the negative electrode material and the positive electrode material is usually held by a current collector. The electrode material is the part excluding the current collector from the electrode plate. There may be members such as a mat and a pasting paper attached to the electrode plate. Since such a member (also referred to as an attachment member) is used integrally with the electrode plate, it is included in the electrode plate. When the electrode plate includes an attachment member (such as a mat or a pasting paper), the electrode material is the part excluding the current collector and the attachment member from the electrode plate.

[0036] Among the positive electrode plates, the clad type positive electrode plate includes a plurality of porous tubes, a core (spine) inserted into each tube, a current collecting part connecting the plurality of cores (spines), a positive electrode material filled in the tubes into which the cores (spines) are inserted, and a seat (spine protector) connecting the plurality of tubes. In the clad type positive electrode plate, the positive electrode material is the part excluding the tubes, the cores (spines), the current collecting part, and the seat (spine protector) from the electrode plate. In the clad type positive electrode plate, the core (spine) and the current collecting part may be collectively referred to as a positive electrode current collector.

[0037] (Density of the positive electrode material) The density of the positive electrode material is the density (g / cm 3 ) obtained by dividing the mass of the positive electrode material by the bulk volume determined by the mercury intrusion method. The density is determined for a sample of the unground positive electrode material taken from the positive electrode plate removed from the lead-acid battery. The unground sample is taken from near the center in the plane direction of the positive electrode plate.

[0038] (Polymer compound) The polymer compound satisfies at least one of the following conditions (i) and (ii). Condition (i) The polymer compound has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1 H-NMR spectrum measured using deuterated chloroform as a solvent. Condition (ii) The polymer compound contains a repeating structure of an oxy C 2-4 alkylene unit.

[0039] In condition (i), the peak in the range of 3.2 ppm or more and 3.8 ppm or less is derived from the oxy C 2-4 alkylene unit. That is, the polymer compound satisfying condition (ii) is also a polymer compound satisfying condition (i). The polymer compound satisfying condition (i) may contain a repeating structure of a monomer unit other than the oxy C 2-4 alkylene unit, and may have a certain molecular weight. The number average molecular weight (Mn) of the polymer compound satisfying the above (i) or (ii) may be, for example, 300 or more.

[0040] (oxy C 2-4 alkylene unit) The oxy C 2-4 alkylene unit is a unit represented by -O-R 1 -(where R 1 represents a C 2-4 alkylene group.)

[0041] (condensate of bisarene compound) The condensate of the bisarene compound is a condensate containing the unit of the bisarene compound. The unit of the bisarene compound refers to the unit derived from the bisarene compound incorporated into the condensate. The bisarene compound is a compound in which two sites each having an aromatic ring are linked via a single bond or a linking group.

[0042] (number average molecular weight) In this specification, the number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used when determining Mn is polyethylene glycol.

[0043] (weight average molecular weight) In this specification, the weight average molecular weight (Mw) is determined by GPC. The standard substance used when determining Mw is sodium polystyrene sulfonate.

[0044] (Fully charged state) The fully charged state of a control valve type lead-acid battery means that in an air tank at 25°C ± 2°C, with a current (A) of 0.2 times the value described in the rated capacity (the value with the unit of Ah), constant current constant voltage charging is performed at 2.23 V / cell, and charging is terminated when the charging current during constant voltage charging reaches a value (A) of 0.005 times the value described in the rated capacity (the value with the unit of Ah).

[0045] A fully charged lead-acid battery refers to a lead-acid battery obtained by fully charging a preformed lead-acid battery. For the full charge of a lead-acid battery, if it is after formation, it may be immediately after formation, or it may be performed after a certain period of time has elapsed since formation (for example, after formation, a lead-acid battery during use (preferably at the initial stage of use) may be fully charged). The battery at the initial stage of use refers to a battery that has not experienced much time elapsed since the start of use and has hardly deteriorated.

[0046] (Vertical direction of the lead-acid battery or its components) In this specification, the vertical direction of a lead-acid battery or its components (such as electrode plates, battery cases, separators, etc.) means the vertical direction in the vertical direction of the lead-acid battery in the state where the lead-acid battery is used. Each of the positive and negative electrode plates is provided with an ear for connection to an external terminal. In some cases, such as a horizontally placed control valve type lead-acid battery, the ear may be provided to protrude laterally from the side of the electrode plate, but in many lead-acid batteries, the ear is usually provided to protrude upward from the upper part of the electrode plate.

[0047] (Small mobility) Small mobility refers to motorcycles and power sports vehicles. Small mobility includes, for example, motorcycles, three-wheeled motorcycles, buggies (including both three-wheeled and four-wheeled ones), water skis, snowmobiles, and all-terrain vehicles. Note that small mobility is equipped with a lead-acid battery for small mobility together with an engine. The lead-acid battery used in or mounted on small mobility (i.e., the lead-acid battery for small mobility) refers to a lead-acid battery included in the scope of application of IEC60095-7:2019 and the scope of application of JIS D 5302:2004.

[0048] Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described for each main component, but the present invention is not limited to the following embodiments.

[0049] [Lead-acid battery] (Negative electrode plate) The negative electrode plate usually includes a negative electrode current collector in addition to the negative electrode active material.

[0050] (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 expansion processing or punching processing. It is preferable to use a grid-shaped current collector as the negative electrode current collector because it is easy to carry the negative electrode active material.

[0051] The lead alloy used for the negative electrode current collector may be any of a Pb-Sb-based alloy, a Pb-Ca-based alloy, and a Pb-Ca-Sn-based alloy. These leads or lead alloys may further contain at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, etc. as an additive element. The negative electrode current collector may have a surface layer. The composition of the surface layer and the inner layer of the negative electrode current collector may be different. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on the ear part of the negative electrode current collector. The surface layer of the ear part may contain Sn or an Sn alloy.

[0052] (Negative electrode active material) The negative electrode material contains the above polymer compound. The negative electrode material further contains a negative electrode active material (specifically, lead or lead sulfate) that exhibits capacitance through a redox reaction. The negative electrode material may contain at least one selected from the group consisting of an organic anti-shrinkage agent, a carbonaceous material, and other additives. Examples of the additive include, but are not limited to, barium sulfate, fibers (such as resin fibers). Note that the negative electrode active material in the charged state is spongy lead, but the unformed negative electrode plate is usually produced using lead powder.

[0053] (Polymer compound) The polymer compound 1 has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1H-NMR spectrum. Such a polymer compound has an oxy-C 2-4 alkylene unit. The oxy-C 2-4 alkylene unit includes an oxyethylene unit, an oxypropylene unit, an oxytrimethylene unit, an oxy-2-methyl-1,3-propylene unit, an oxy-1,4-butylene unit, an oxy-1,3-butylene unit, etc. The polymer compound may have one kind of such oxy-C 2-4 alkylene unit or two or more kinds.

[0054] The polymer compound preferably contains a repeating structure of an oxy-C 2-4 alkylene unit. The repeating structure may contain one kind of oxy-C 2-4 alkylene unit or two or more kinds of oxy-C 2-4 alkylene units. The polymer compound may contain one kind of the above repeating structure or two or more kinds of the above repeating structures.

[0055] Oxy-C 2-4 The polymer compound having a repeating structure of an alkylene unit also includes a polymer compound classified as a surfactant (more specifically, a nonionic surfactant).

[0056] Examples of the polymer compound include, for example, hydroxy compounds having a repeating structure of oxy C 2-4 alkylene units (poly C 2-4 alkylene glycol, copolymer containing a repeating structure of oxy C 2-4 alkylene, polyalkylene oxide adduct of polyol, etc.), etherified products or esterified products of these hydroxy compounds, and the like. 2-4 Examples of the copolymer include copolymers containing different oxy C

[0057] alkylene units. The copolymer may be a block copolymer. 2-4 Examples of the copolymer include copolymers containing different oxy C

[0058] The polyol may be any of aliphatic polyols, alicyclic polyols, aromatic polyols, and heterocyclic polyols. From the viewpoint that the polymer compound easily spreads thinly on the lead surface, aliphatic polyols, alicyclic polyols (for example, polyhydroxycyclohexane, polyhydroxynorbornane), etc. are preferable, and among them, aliphatic polyols are more preferable. Examples of the aliphatic polyol include aliphatic diols, polyols having three or more hydroxyl groups (for example, glycerin, trimethylolpropane, pentaerythritol, sugar or sugar alcohol). 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, etc. The sugar or sugar alcohol may have either a linear structure or a cyclic structure. In the polyalkylene oxide adduct of the polyol, the alkylene oxide corresponds to the oxy C 2-4 alkylene unit of the polymer compound and contains at least C 2-4 alkylene oxide. From the viewpoint that the polymer compound easily takes a linear structure, the polyol is preferably a diol.

[0059] The etherified product has an -OR 2-4 group in which at least a part of the -OH groups (the -OH groups composed of the hydrogen atom of the terminal group and the oxygen atom bonded to this hydrogen atom) at the terminals of the hydroxy compound having a repeating structure of the oxyC 2 alkylene unit are etherified (wherein R 2 is an organic group). Among the terminals of the polymer compound, some terminals may be etherified, or all terminals may be etherified. For example, one terminal of the main chain of a linear polymer compound may be an -OH group and the other terminal may be an -OR 2 group.

[0060] The esterified product has an -O-C(=O)-R 2-4 group in which at least a part of the -OH groups (the -OH groups composed of the hydrogen atom of the terminal group and the oxygen atom bonded to this hydrogen atom) at the terminals of the hydroxy compound having a repeating structure of the oxyC 3 alkylene unit are esterified (wherein R 3 is an organic group). Among the terminals of the polymer compound, some terminals may be esterified, or all terminals may be esterified. For example, one terminal of the main chain of a linear polymer compound may be an -OH group and the other terminal may be an -O-C(=O)-R 3 group.

[0061] Examples of each of the organic groups R 2 and R 3 include hydrocarbon groups. The hydrocarbon group also includes a hydrocarbon group having a substituent (for example, a hydroxy group, an alkoxy group, and / or a carboxy group). The hydrocarbon group may be any of aliphatic, alicyclic, and aromatic. 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) as a substituent. The number of carbon atoms of the aliphatic hydrocarbon group as a substituent may be, for example, 1 to 30, or may be 1 to 20 or 1 to 10, or may be 1 to 6 or 1 to 4.

[0062] Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 24 or fewer carbon atoms (e.g., 6 to 24). The number of carbon atoms of the aromatic hydrocarbon group may be 20 or fewer (e.g., 6 to 20), 14 or fewer (e.g., 6 to 14), or 12 or fewer (e.g., 6 to 12). Examples of the aromatic hydrocarbon group include an aryl group, a bisaryl group, etc. Examples of the aryl group include a phenyl group, a naphthyl group. Examples of the bisaryl group include a monovalent group corresponding to bisarene. Examples of bisarene include biphenyl, bisarylalkane (e.g., bisC 6-10 arylC 1-4 alkane (such as 2,2-bisphenylpropane)).

[0063] Examples of the alicyclic hydrocarbon group include alicyclic hydrocarbon groups having 16 or fewer carbon atoms. The alicyclic hydrocarbon group may be a bridged cyclic hydrocarbon group. The number of carbon atoms of the alicyclic hydrocarbon group may be 10 or fewer or 8 or fewer. The number of carbon atoms of the alicyclic hydrocarbon group is, for example, 5 or more, and may be 6 or more.

[0064] The number of carbon atoms of the alicyclic hydrocarbon group may be 5 (or 6) or more and 16 or fewer, 5 (or 6) or more and 10 or fewer, or 5 (or 6) or more and 8 or fewer.

[0065] Examples of the alicyclic hydrocarbon group include a cycloalkyl group (such as a cyclopentyl group, a cyclohexyl group, a cyclooctyl group), a cycloalkenyl group (such as a cyclohexenyl group, a cyclooctenyl group), etc. The alicyclic hydrocarbon group includes hydrogenated products of the above aromatic hydrocarbon groups.

[0066] From the viewpoint that the polymer compound easily adheres thinly to the lead surface, among the hydrocarbon groups, an aliphatic hydrocarbon group is preferable. The aliphatic hydrocarbon group 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, a trienyl group having three carbon-carbon double bonds, and the like. The aliphatic hydrocarbon group may be either linear or branched.

[0067] The number of carbon atoms of the aliphatic hydrocarbon group is, for example, 30 or less, and may be 26 or less, 22 or less, 20 or less, 16 or less, 14 or less, 10 or less, 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. Among them, an alkyl group and an alkenyl group are preferable from the viewpoint that the polymer compound easily adheres thinly to the lead surface.

[0068] 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, 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, icosyl, heneicosyl, behenyl.

[0069] Specific examples of the alkenyl group include vinyl, 1-propenyl, allyl, cis-9-heptadecen-1-yl, palmitoleyl, oleyl. The alkenyl group may be, for example, C 2-30 alkenyl group or C 2-26 alkenyl group, and may be C 2-22 alkenyl group or C 2-20 alkenyl group, and may be C 10-20 alkenyl group.

[0070] Among the polymer compounds, an etherified product of a hydroxy compound having a repeating structure of an oxy C 2-4 alkylene unit and an esterified product of a hydroxy compound having a repeating structure of an oxy C 2-4 alkylene unit, at least one selected from the group consisting of is preferably used because self-discharge can be further reduced. Among such polymer compounds, a polymer compound having a repeating structure of an oxypropylene unit, a polymer compound having a repeating structure of an oxyethylene unit, etc. are preferable.

[0071] The polymer compound may have one or more hydrophobic groups. Examples of the hydrophobic group include, among the above hydrocarbon groups, an aromatic hydrocarbon group, an alicyclic hydrocarbon group, and a long-chain aliphatic hydrocarbon group. Examples of the long-chain aliphatic hydrocarbon group include, among the above aliphatic hydrocarbon groups (alkyl group, alkenyl group, etc.), an aliphatic hydrocarbon group having 8 or more carbon atoms, preferably 12 or more, and more preferably 16 or more. Among them, a polymer compound having a long-chain aliphatic hydrocarbon group is preferable because it hardly causes excessive adsorption to lead and is likely to ensure higher low-temperature HR discharge performance while suppressing self-discharge to a low level. The polymer compound may be a polymer compound in which at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group. The number of carbon atoms of the long-chain aliphatic hydrocarbon group may be 30 or less, 26 or less, or 22 or less.

[0072] The number of carbon atoms of the long-chain aliphatic hydrocarbon group may be 8 or more (or 12 or more) and 30 or less, 8 or more (or 12 or more) and 26 or less, 8 or more (or 12 or more) and 22 or less, 10 or more and 30 or less (or 26 or less), or 10 or more and 22 or less.

[0073] Among polymer compounds, a polymer compound having a hydrophilic group and a hydrophobic group corresponds to a nonionic surfactant. The repeating structure of the oxyethylene unit exhibits high hydrophilicity and can serve as the hydrophilic group in a nonionic surfactant. Therefore, it is preferable that the polymer compound having the above hydrophobic group contains the repeating structure of the oxyethylene unit. Such a polymer compound can suppress excessive coverage of the lead surface while selectively adsorbing to lead due to the balance between hydrophobicity and high hydrophilicity due to the repeating structure of the oxyethylene unit. Therefore, it is possible to ensure higher low-temperature HR discharge performance while keeping self-discharge low. Such a polymer compound can ensure high adsorptivity to lead even if it has a relatively low molecular weight (for example, Mn is 1000 or less).

[0074] Among the above polymer compounds, polyoxypropylene-polyoxyethylene block copolymers, etherified products of hydroxy compounds having a repeating structure of oxyethylene units, esterified products of hydroxy compounds having a repeating structure of oxyethylene units, etc. correspond to nonionic surfactants.

[0075] In the case of polyoxypropylene-polyoxyethylene block copolymers, etc., the repeating structure of the oxyethylene unit corresponds to the hydrophilic group, and the repeating structure of the oxypropylene unit corresponds to the hydrophobic group. Such copolymers are also included in the polymer compounds having a hydrophobic group.

[0076] It is preferable that the polymer compound having a hydrophobic group contains the repeating structure of the oxyethylene unit. Such a polymer compound can suppress excessive coverage of the lead surface while selectively adsorbing to lead due to the balance between hydrophobicity and high hydrophilicity due to the repeating structure of the oxyethylene unit. Therefore, it is possible to ensure higher low-temperature HR discharge performance while keeping self-discharge low. Such a polymer compound can ensure high adsorptivity to lead even if it has a relatively low molecular weight (for example, Mn is 1000 or less).

[0077] Examples of the polymer compound having a hydrophobic group and including a repeating structure of oxyethylene units include etherified products of polyethylene glycol (such as alkyl ethers), esterified products of polyethylene glycol (such as carboxylic acid esters), etherified products of the polyethylene oxide adducts of the above polyols (such as alkyl ethers), and esterified products of the polyethylene oxide adducts of the above polyols (such as polyols with three or more hydroxyl groups) (such as carboxylic acid esters). Specific examples of such polymer compounds include polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene coconut oil fatty acid sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether. However, the polymer compound is not limited thereto. Among them, it is preferable to use esterified products of polyethylene glycol and esterified products of the polyethylene oxide adducts of the above polyols because self-discharge can be further reduced and higher low-temperature HR discharge performance can be ensured.

[0078] Among the polymer compounds, from the viewpoint of being more likely to further reduce self-discharge for the polymer compounds classified as surfactants, the HLB of the polymer compound is preferably 4 or more, or 4.3 or more. The HLB of the polymer compound is, for example, 18 or less. From the viewpoint of being more likely to ensure higher low-temperature HR discharge performance, the HLB of the polymer compound is preferably 10 or less, or 9 or less, and more preferably 8.5 or less.

[0079] The HLB of the polymer compound may be 4 or more (or 4.3 or more) and 18 or less, or 4 or more (or 4.3 or more) and 10 or less. From the viewpoint of excellent balance between reduction of self-discharge and improvement of low-temperature HR discharge performance, the HLB of the polymer compound is preferably 4 or more (or 4.3 or more) and 9 or less, or 4 or more (or 4.3 or more) and 8.5 or less. Incidentally, HLB is the abbreviation of Hydrophile Lipophile Balance, and is a numerical value representing the balance between the hydrophobicity and hydrophilicity of nonionic surfactants.

[0080] Oxy C 2-4 It is also preferable that the repeating structure of alkylene includes at least the repeating structure of oxypropylene units. In this case, compared with the case of the repeating structure of oxyethylene units, self-discharge tends to increase. However, even in this case, by controlling the density of the positive electrode material, self-discharge can be suppressed to a low level. The polymer compound containing oxypropylene units 1 In the chemical shift of the 1H-NMR spectrum, in the range of 3.2 ppm to 3.8 ppm, there are peaks derived from -CH and -CH of the oxypropylene units 2 - Since the electron density around the nuclei of hydrogen atoms in these groups is different, the peaks are in a split state. Such a polymer compound 1 In the chemical shift of the 1H-NMR spectrum, for example, it has peaks in each of the range of 3.2 ppm or more and 3.42 ppm or less, and the range of more than 3.42 ppm and 3.8 ppm or less. The peak in the range of 3.2 ppm or more and 3.42 ppm or less is derived from -CH 2 -, and the peak in the range of more than 3.42 ppm and 3.8 ppm or less is derived from -CH and -CH 2 -.

[0081] Examples of the polymer compound containing at least the repeating structure of oxypropylene units include polypropylene glycol, a copolymer containing the repeating structure of oxypropylene units, a polypropylene oxide adduct of the above polyol, or an etherified or esterified product thereof. Examples of the copolymer include an oxypropylene-oxyalkylene copolymer (however, oxyalkylene is C other than oxypropylene 2-4Examples include (alkylene). Examples of the oxypropylene-oxyalkylene copolymer include oxypropylene-oxyethylene copolymer, oxypropylene-oxytrimethylene copolymer, etc. The oxypropylene-oxyalkylene copolymer may be referred to as a polyoxypropylene-polyoxyalkylene copolymer (for example, polyoxypropylene-polyoxyethylene copolymer). The oxypropylene-oxyalkylene copolymer may be a block copolymer (for example, polyoxypropylene-polyoxyethylene block copolymer). Examples of the etherified product include polypropylene glycol alkyl ether, alkyl ether of oxypropylene-oxyalkylene copolymer (such as alkyl ether of polyoxypropylene-polyoxyethylene copolymer), etc. Examples of the esterified product include polypropylene glycol ester of carboxylic acid, carboxylic acid ester of oxypropylene-oxyalkylene copolymer (such as carboxylic acid ester of polyoxypropylene-polyoxyethylene copolymer), etc.

[0082] Examples of the polymer compound containing at least the repeating structure of the oxypropylene unit include, for example, polypropylene glycol, polyoxypropylene-polyoxyethylene copolymer (such as polyoxypropylene-polyoxyethylene block copolymer), polypropylene glycol alkyl ether (wherein R 2 is an alkyl having 10 or less carbon atoms (or 8 or less or 6 or less) (such as methyl ether, ethyl ether, butyl ether, etc.)), polyoxyethylene-polyoxypropylene alkyl ether (wherein R 2 is an alkyl having 10 or less carbon atoms (or 8 or less or 6 or less) (such as butyl ether, hydroxyhexyl ether, etc.)), polypropylene glycol carboxylic acid (wherein R 3Carboxylic acid polypropylene glycols (such as acetic acid polypropylene glycol) where the alkyl group has 10 or fewer carbon atoms (alternatively 8 or fewer or 6 or fewer carbon atoms), polypropylene oxide adducts of polyols with three or more hydroxyl groups (such as polypropylene oxide adduct of glycerin), etc. However, the polymer compound is not limited to these.

[0083] From the perspective that the adsorbability of the polymer compound to lead increases and the polymer compound is more likely to adopt a linear structure, the polymer compound preferably contains many oxy C 2-4 alkylene units. Such a polymer compound contains, for example, an oxygen atom bonded to a terminal group, and a -CH 2 - group and / or a -CH< group bonded to the oxygen atom. In the 1 1H-NMR spectrum of the polymer compound, the ratio of the integrated value of the peak at 3.2 ppm to 3.8 ppm to the total of the integrated values of the peaks of the hydrogen atoms of the -CH 2 - group and the integrated value of the peak of the hydrogen atoms of the -CH< group increases. This ratio is, for example, 50% or more, and may be 80% or more. From the perspective of further reducing self-discharge, the above ratio is preferably 85% or more, and more preferably 90% or more. For example, when the polymer compound has an -OH group at the terminal and has a -CH 2 - group and / or a -CH< group bonded to the oxygen atom of this -OH group, 1 in the 1H-NMR spectrum, the peaks of the hydrogen atoms of the -CH 2 - group and the -CH< group are in the range where the chemical shift exceeds 3.8 ppm and is 4.0 ppm or less.

[0084] The negative electrode material may contain one kind of polymer compound or two or more kinds of polymer compounds.

[0085] The polymer compound may include, for example, compounds with a Mn of 5 million or less, may include compounds with a Mn of 1 million or less or 100,000 or less, and may include compounds with a Mn of 20,000 or less. From the perspective of ensuring higher charge acceptance, it is preferable that the polymer compound includes compounds with a Mn of 10,000 or less, and may include compounds with a Mn of 5,000 or less or 3,000 or less, and may include compounds with a Mn of 2,500 or less or 2,000 or less. The Mn of such a compound may be 300 or more or 400 or more, and may be 500 or more. As the polymer compound, two or more compounds with different Mn may be used. That is, the polymer compound may be a polymer compound having a plurality of Mn peaks in the molecular weight distribution.

[0086] The Mn of the above compound may be 300 or more and 5 million or less (or 1 million or less), 400 or more and 5 million or less (or 1 million or less), 500 or more and 5 million or less (or 1 million or less), 300 or more and 100,000 or less (or 20,000 or less), 400 or more and 100,000 or less (or 20,000 or less), 500 or more and 100,000 or less (or 20,000 or less), 300 or more and 10,000 or less (or 5,000 or less), 400 or more and 10,000 or less (or 5,000 or less), 500 or more and 10,000 or less (or 5,000 or less), 300 or more and 3,000 or less (or 2,500 or less), 400 or more and 3,000 or less (or 2,500 or less), 500 or more and 3,000 or less (or 2,500 or less), 300 or more (or 400 or more) and 2,000 or less, or 500 or more and 2,000 or less.

[0087] The content of the polymer compound in the negative electrode material is, for example, 8 ppm or more on a mass basis. From the viewpoint of further reducing self-discharge, the content of the polymer compound in the negative electrode material is preferably 10 ppm or more, preferably 20 ppm or more, and more preferably 30 ppm or more on a mass basis. The content of the polymer compound in the negative electrode material is, for example, 1000 ppm or less, may be 500 ppm or less, may be 450 ppm or less, or may be 420 ppm or less on a mass basis. From the viewpoint of easily ensuring higher low-temperature HR discharge performance, the content of the polymer compound in the negative electrode material is preferably 370 ppm or less, and may be 350 ppm or less on a mass basis.

[0088] The content (mass basis) of the polymer compound in the negative electrode material is 8 ppm or more (or 10 ppm or more) and 1000 ppm or less, 8 ppm or more (or 10 ppm or more) and 500 ppm or less, 8 ppm or more (or 10 ppm or more) and 450 ppm or less, 8 ppm or more (or 10 ppm or more) and 420 ppm or less, 8 ppm or more (or 10 ppm or more) and 370 ppm or less, 8 ppm or more (or 10 ppm or more) and 350 ppm or less, 20 ppm or more (or 30 ppm or more) and 1000 ppm or less, 20 ppm or more (or 30 ppm or more) and 500 ppm or less, 20 ppm or more (or 30 ppm or more) and 450 ppm or less, 20 ppm or more (or 30 ppm or more) and 420 ppm or less, 20 ppm or more (or 30 ppm or more) and 370 ppm or less, 20 ppm or more (or 30 ppm or more) and 350 ppm or less.

[0089] (Organic anti-shrinkage agent) The organic anti-shrinkage agent is an organic compound among the compounds having a function of suppressing the shrinkage of lead, which is the negative electrode active material, when the charge and discharge of the lead storage battery are repeated. The organic anti-shrinkage agent is generally classified into a lignin compound and a synthetic organic anti-shrinkage agent. The synthetic organic anti-shrinkage agent can also be said to be an organic anti-shrinkage agent other than the lignin compound. Examples of the organic anti-shrinkage agent contained in the negative electrode material include a lignin compound and a synthetic organic anti-shrinkage agent. The negative electrode material may contain one kind of the organic anti-shrinkage agent or two or more kinds thereof.

[0090] Examples of the lignin compound include lignin and lignin derivatives. Examples of the lignin derivative include lignin sulfonic acid or its salt (such as an alkali metal salt (such as a sodium salt)).

[0091] The synthetic organic shrinkage inhibitor is an organic polymer containing sulfur element. Generally, it contains a plurality of aromatic rings in the molecule and contains sulfur element as a sulfur-containing group. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group in a stable form is preferred. The sulfonic acid group may exist in an acid form or in a salt form such as a Na salt.

[0092] From the viewpoint of further reducing self-discharge, at least a lignin compound may be used as the organic shrinkage inhibitor.

[0093] As the organic shrinkage inhibitor, it is also preferable to use a condensate containing at least a unit of an aromatic compound. Examples of such a condensate include condensates of an aromatic compound with at least one selected from the group consisting of aldehyde compounds (such as aldehydes (e.g., formaldehyde) and their condensates). The organic shrinkage inhibitor may contain a unit of one kind of aromatic compound or may contain units of two or more kinds of aromatic compounds. Note that the unit of the aromatic compound refers to a unit derived from the aromatic compound incorporated into the condensate.

[0094] Examples of the aromatic ring of 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, etc.). Examples of such a structure include a bisarene structure (biphenyl, bisphenylalkane, bisphenylsulfone, etc.). Examples of the aromatic compound include a compound having at least one selected from the group consisting of the above aromatic ring and 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. Note that the hydroxy group also includes a salt (-OMe) of the hydroxy group. The amino group also includes a salt of the amino group (specifically, a salt with an anion). Examples of Me include an alkali metal (Li, K, Na, etc.), a Group 2 metal of the periodic table (Ca, Mg, etc.).

[0095] Preferred aromatic compounds 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.), hydroxyarene compounds (hydroxynaphthalene compounds, phenol compounds, etc.), aminoarene compounds (aminonaphthalene compounds, aniline compounds (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc.), etc.)]. The aromatic compound may further have a substituent. The organic shrinkage inhibitor may contain residues of these compounds, either one kind or a plurality of kinds. Preferred bisphenol compounds include bisphenol A, bisphenol S, bisphenol F, etc. When the negative electrode material contains a condensate of a bisarene compound (such as a condensate with an aldehyde compound), self-discharge tends to increase. However, when the negative electrode material contains a polymer compound and the density of the positive electrode material is controlled within a specific range, self-discharge can be suppressed to a low level.

[0096] The condensate preferably contains units of an aromatic compound having at least a sulfur-containing group. Among them, when using a condensate containing at least units of a bisphenol compound having a sulfur-containing group, high high-temperature durability can be obtained, which is advantageous for ensuring excellent life performance. From the viewpoint of further reducing self-discharge by further increasing the hydrogen overvoltage, it is also preferable to use a condensate formed from an aldehyde compound of a naphthalene compound having a sulfur-containing group and at least one selected from the group consisting of a hydroxy group and an amino group.

[0097] The sulfur-containing group may be directly bonded to the aromatic ring contained in the compound. For example, it may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group. The sulfur-containing group is not particularly limited, and examples thereof include a sulfonyl group, a sulfonic acid group or a salt thereof.

[0098] Also, as the organic anti-shrinkage agent, for example, at least one selected from the group consisting of units of the above bisarene compound and units of a monocyclic aromatic compound (such as a hydroxyarene compound and / or an aminoarene compound) may be used at least. The organic anti-shrinkage agent may at least contain a condensate containing units of a bisarene compound and units of a monocyclic aromatic compound (among them, a hydroxyarene compound). Examples of such a condensate include a condensate of a bisarene compound and a monocyclic aromatic compound with an aldehyde compound. As the hydroxyarene compound, a phenolsulfonic acid compound (such as phenolsulfonic acid or a substituent thereof) is preferable. As the aminoarene compound, aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc. are preferable. As the monocyclic aromatic compound, a hydroxyarene compound is preferable.

[0099] The negative electrode material may contain, for example, an organic anti-shrinkage agent having a sulfur element content of 2000 μmol / g or more (the first organic anti-shrinkage agent) among the above organic anti-shrinkage agents. Examples of the first organic anti-shrinkage agent include the above synthetic organic anti-shrinkage agents (such as the above condensates).

[0100] The sulfur element content in the first organic shrinkage inhibitor being X μmol / g means that the content of sulfur element contained per 1 g of the first organic shrinkage inhibitor is X μmol.

[0101] The sulfur element content of the first organic shrinkage inhibitor may be 2000 μmol / g or more, preferably 3000 μmol / g or more. The upper limit of the sulfur element content of the first organic shrinkage inhibitor is not particularly limited. From the viewpoint of further enhancing the effect of reducing the overcharge amount, the sulfur element content of the first organic shrinkage inhibitor is preferably 9000 μmol / g or less, more preferably 8000 μmol / g or less.

[0102] The sulfur element content of the first organic shrinkage inhibitor may be, for example, 2000 μmol / g or more (or 3000 μmol / g or more) and 9000 μmol / g or less, or 2000 μmol / g or more (or 3000 μmol / g or more) and 8000 μmol / g or less.

[0103] The first organic shrinkage inhibitor 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.

[0104] The weight average molecular weight (Mw) of the first organic shrinkage inhibitor is preferably 7000 or more. The Mw of the first organic shrinkage inhibitor may be, for example, 100,000 or less, or 20,000 or less.

[0105] The negative electrode material may contain, for example, an organic shrinkage inhibitor (second organic shrinkage inhibitor) having a sulfur element content of less than 2000 μmol / g. Examples of the second organic shrinkage inhibitor include lignin compounds and synthetic organic shrinkage inhibitors (especially lignin compounds) among the above-mentioned organic shrinkage inhibitors. The sulfur element content of the second organic shrinkage inhibitor 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 inhibitor is not particularly limited, and is, for example, 400 μmol / g or more.

[0106] The Mw of the second anti-shrinkage agent is, for example, less than 7000. The Mw of the second anti-shrinkage agent is, for example, 3000 or more.

[0107] The negative electrode material may contain a first anti-shrinkage agent and a second anti-shrinkage agent. When the first anti-shrinkage agent and the second anti-shrinkage agent are used in combination, their mass ratio can be arbitrarily selected.

[0108] The content of the anti-shrinkage agent contained in the negative electrode material is, for example, 0.005% by mass or more, may be 0.01% by mass or more, and may be 0.1% by mass or more. When the content of the anti-shrinkage agent is in such a range, higher low-temperature HR discharge performance is easily obtained. The content of the anti-shrinkage agent is, for example, 1.0% by mass or less, and may be 0.5% by mass or less.

[0109] The content of the anti-shrinkage agent contained in the negative electrode material may be 0.005% by mass or more (or 0.01% by mass or more) and 1.0% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) and 0.5% by mass or less, or 0.1% by mass or more and 1.0% by mass or less (or 0.5% by mass or less).

[0110] (Carbonaceous material) As the carbonaceous material contained in the negative electrode material, carbon black, graphite, hard carbon, soft carbon, etc. can be used. Examples of carbon black include acetylene black, furnace black, lamp black, etc. Furnace black also includes ketjen black (trade name). 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.

[0111] The content of the carbonaceous material in the negative electrode material is, for example, 0.05% by mass or more, and may be 0.1% by mass or more. When the content of the carbonaceous material is 0.1% by mass or more, self-discharge tends to increase. However, even in such a case, according to the lead-acid battery of the first side and the second side, self-discharge can be suppressed to a low level. The content of the carbonaceous material in the negative electrode material is, for example, 5% by mass or less, and may be 3% by mass or less. From the viewpoint of further reducing self-discharge, the content of the carbonaceous material in the negative electrode material is preferably 1.2% by mass or less.

[0112] The content of the carbonaceous material in the negative electrode material may be 0.05% by mass or more and 5% by mass or less, 0.05% by mass or more and 3% by mass or less (or 1.2% by mass or less), 0.1% by mass or more and 5% by mass or less, or 0.1% by mass or more and 3% by mass or less (or 1.2% by mass or less).

[0113] (Barium sulfate) The content of barium sulfate in the negative electrode material is, for example, 0.05% by mass or more, and may be 0.10% by mass or more. The content of barium sulfate in the negative electrode material is, for example, 3% by mass or less, and may be 2% by mass or less.

[0114] The content of barium sulfate in the negative electrode material may be 0.05% by mass or more and 3% by mass or less, 0.05% by mass or more and 2% by mass or less, 0.10% by mass or more and 3% by mass or less, or 0.10% by mass or more and 2% by mass or less.

[0115] (Analysis of the constituent components of the negative electrode material) The method for analyzing a negative electrode material or its constituent components will be described below. Prior to measurement or analysis, a fully charged lead storage 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. The water washing is performed until it is confirmed that the pH test paper does not change color when pressed against the surface of the washed negative electrode plate. However, the time for performing the water washing shall be within 2 hours. The washed negative electrode plate is dried at 60 ± 5 °C for about 6 hours in a reduced-pressure environment. When the negative electrode plate contains an adhered member, the adhered 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 necessary and subjected to analysis.

[0116] (1) Analysis of Polymer Compounds (1-1) Qualitative Analysis of Polymer Compounds (a) Oxy C 2-4 Analysis of Alkylene Units Pulverized 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. Thereafter, the solid content is removed by filtration. For the chloroform solution in which the polymer compound obtained by extraction is dissolved or the polymer compound obtained by drying the chloroform solution to dryness, information is obtained from at least one selected from infrared absorption spectrum, ultraviolet-visible absorption spectrum, NMR spectrum, LC-MS, and pyrolysis GC-MS to identify the polymer compound.

[0117] From the chloroform solution in which the polymer compound obtained by extraction is dissolved, the chloroform-soluble component is recovered by distilling off the chloroform under reduced pressure. The chloroform-soluble component is dissolved in deuterated chloroform and measured for the 1 1H-NMR spectrum under the following conditions. From this 1 1H-NMR spectrum, peaks in the range where the chemical shift is 3.2 ppm or more and 3.8 ppm or less are confirmed. Also, from the peaks in this range, the types of oxy C 2-4 alkylene units are identified.

[0118] Apparatus: AL400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. Observation frequency: 395.88MHz Pulse width: 6.30μs Pulse repetition time: 74.1411 seconds Accumulation count: 32 Measurement temperature: room temperature (20~35℃) Standard: 7.24 ppm Sample tube diameter: 5mm

[0119] 1 The integral value (V 1 ) is calculated. Also, the -CH bonded to the oxygen atom bonded to the end group of the polymer compound is calculated. 2 For each hydrogen atom of the - group and the -CH< group, 1 The sum of the integrals of the peaks in the H-NMR spectrum (V 2 ) and V 1 and V 2 From V 1 V 1 and V 2 Percentage of the total (=V 1 / (V 1 +V 2 ) × 100(%).

[0120] In addition, in the qualitative analysis, 1 When calculating the integral value of a peak in a H-NMR spectrum, 1 In the H-NMR spectrum, two points without significant signals are determined so as to sandwich the corresponding peak, and each integral value is calculated using a straight line connecting these two points as a baseline. For example, for a peak that exists in a chemical shift range of 3.2 ppm to 3.8 ppm, a straight line connecting two points on the spectrum between 3.2 ppm and 3.8 ppm is used as the baseline. For example, for a peak that exists in a chemical shift range of more than 3.8 ppm to 4.0 ppm, a straight line connecting two points on the spectrum between 3.8 ppm and 4.0 ppm is used as the baseline.

[0121] (b) Analysis of the hydrophobic group in the esterified product When the polymer compound is an esterified product of a hydroxy compound, in the above (a), a predetermined amount of the polymer compound obtained by drying the chloroform solution in which the polymer compound obtained by extraction is dissolved is collected, and an aqueous potassium hydroxide solution is added. As a result, the esterified product is saponified to produce a potassium fatty acid salt and a hydroxy compound. The above-mentioned water-soluble potassium aqueous solution is added until the saponification is complete. By adding a solution of methanol and boron trifluoride to the resulting mixture and mixing, the potassium fatty acid salt is converted into a fatty acid methyl ester. The resulting mixture is analyzed under the following conditions by pyrolysis GC-MS to identify the hydrophobic group contained in the esterified product. Analyzer: High-performance general-purpose gas chromatogram GC-2014 manufactured by Shimadzu Corporation Column: DEGS (diethylene glycol succinate) 2.1 m Oven temperature: 180 - 120 °C Inlet temperature: 240 °C Detector temperature: 240 °C Carrier gas: He (flow rate: 50 mL / min) Injection volume: 1 μL - 2 μL

[0122] (c) Analysis of the hydrophobic group in the etherified product When the polymer compound is an etherified product of a hydroxy compound, in the above (a), a predetermined amount of the polymer compound obtained by drying the chloroform solution in which the polymer compound obtained by extraction is dissolved is collected, and hydrogen iodide is added. As a result, an iodide (R 3 ) corresponding to the organic group of the ether moiety of the polymer compound (R 3 ) is generated, and a diiodoalkane corresponding to the oxy C 2-4 alkylene unit is generated. The above-mentioned hydrogen iodide is the iodide of the etherified product and the diiodo C 2-4 alkane corresponding to the oxy C 2-4Add an amount sufficient for the conversion to alkane to be completed. The resulting mixture is analyzed under the same conditions as in (b) above by pyrolysis GC-MS to identify the hydrophobic groups contained in the etherified product.

[0123] (1-2) Quantitative analysis of polymer compound An appropriate amount of the above chloroform-soluble component was measured with an accuracy of ±0.0001 g as m r (g) was dissolved in deuterated chloroform together with tetrachloroethane (TCE) to 1 measure the 1H-NMR spectrum. The integrated value (S a ) of the peak present in the chemical shift range of 3.2 to 3.8 ppm and the integrated value (S r ) of the peak derived from TCE were determined, and the content C n (ppm) of the polymer compound in the negative electrode material on a mass basis was determined from the following formula.

[0124] C n = S a / S r × N r / N a × M a / M r × m r / m × 1000000 (In the formula, M a is the molecular weight of the structure showing a peak in the chemical shift range of 3.2 to 3.8 ppm (more specifically, the molecular weight of the repeating structure of oxy C 2-4 alkylene units), N a is the number of hydrogen atoms bonded to the carbon atoms in the main chain of the repeating structure. N r、 M r are the number of hydrogen atoms contained in the molecule of the reference substance and the molecular weight of the reference substance, respectively, and m (g) is the mass of the negative electrode material used for extraction.) Note that since the reference substance in this analysis is TCE, N r = 2, M r = 168. Also, m = 100.

[0125] For example, when the polymer compound is polypropylene glycol, M a is 58, and Na is 3. When the polymer compound is polyethylene glycol, M a is 44 and N a is 4. In the case of the copolymer, N a and M a are the values obtained by averaging the N a value and the M a value of each monomer unit using the molar ratio (mol%) of each monomer unit contained in the repeating structure.

[0126] In quantitative analysis, 1 the integral value of the peak in the 1H-NMR spectrum is determined using the data processing software "ALICE" manufactured by JEOL Ltd.

[0127] (1-3) Measurement of Mn of Polymer Compound Using the above chloroform-soluble component, the GPC measurement of the polymer compound is carried out using the following apparatus under the following conditions. Separately, a calibration curve (calibration line) is created from the plot of Mn of the standard substance and the elution time. Based on this calibration curve and the GPC measurement result of the polymer compound, Mn of the polymer compound is calculated. However, the esterified product or etherified product, etc. may be in a decomposed state in the chloroform-soluble component.

[0128] Analysis system: 20A system (manufactured by Shimadzu Corporation) Column: Two 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 mass% Injection volume: 10 μL Standard substance: Polyethylene glycol (Mn = 2,000,000, 200,000, 20,000, 2,000, 200) Detector: Differential refractive index detector (manufactured by Shodex, Shodex RI-201H)

[0129] (2) Analysis of Organic Antishrinkage Agent (2-1) Qualitative Analysis of the Organic Anti-Shrinkage Agent in the Negative Electrode Material The pulverized sample A is immersed in a 1 mol / L aqueous sodium hydroxide solution to extract the organic anti-shrinkage agent. Next, the first organic anti-shrinkage agent and the second organic anti-shrinkage agent are separated from the extract as necessary. For each of the separated substances containing the organic anti-shrinkage agent, the insoluble components are removed by filtration, and the resulting solution is desalted, concentrated, and dried after that. Desalting 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 the organic anti-shrinkage agent (hereinafter referred to as sample B) is obtained.

[0130] Combining the information obtained from the infrared spectroscopic spectrum measured using the organic anti-shrinkage agent sample B thus obtained, the ultraviolet-visible absorption spectrum measured with an ultraviolet-visible spectrophotometer after diluting sample B with distilled water or the like, the NMR spectrum of the solution obtained by dissolving sample B in a predetermined solvent such as heavy water, or the information obtained from thermal decomposition GC-MS or the like that can obtain information on the individual compounds constituting the substance, the type of the organic anti-shrinkage agent is specified.

[0131] The separation of the first organic shrink-proofing agent and the second organic shrink-proofing agent from the above extract is carried out as follows. First, the above extract is measured by infrared spectroscopy, NMR, and / or GC-MS to determine whether it contains multiple types of organic shrink-proofing agents. Next, the molecular weight distribution is measured by GPC analysis of the above extract. If multiple types of organic shrink-proofing agents can be separated by molecular weight, the organic shrink-proofing agents are separated by column chromatography based on the difference in molecular weight. When separation by the difference in molecular weight is difficult, one of the organic shrink-proofing agents is separated by precipitation separation using the difference in solubility depending on the type and / or amount of the functional groups possessed by the organic shrink-proofing agents. Specifically, an aqueous sulfuric acid solution is added dropwise to a mixture obtained by dissolving the above extract in an aqueous NaOH solution to adjust the pH of the mixture, thereby aggregating and separating one of the organic shrink-proofing agents. The insoluble components are removed by filtration from the mixture obtained by dissolving the separated product in an aqueous NaOH solution again as described above. 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 components are removed by filtration from this concentrate as described above.

[0132] (2-2) Quantification of the content of the organic shrink-proofing agent in the negative electrode material Similar to the above (2-1), solutions are obtained by removing the insoluble components by filtration from each of the separated products containing the organic shrink-proofing agent. The ultraviolet-visible absorption spectra are measured for the obtained solutions. Using the intensity of the peaks characteristic of each organic shrink-proofing agent and the calibration curve prepared in advance, the content of each organic shrink-proofing agent in the negative electrode material is determined.

[0133] When obtaining a lead-acid battery with an unknown content of the organic shrink-proofing agent and measuring the content of the organic shrink-proofing agent, since the exact structure formula of the organic shrink-proofing agent cannot be specified, the same organic shrink-proofing agent may not be used for the calibration curve. In this case, a calibration curve is prepared using an organic polymer that can be separately obtained and has a similar shape in the ultraviolet-visible absorption spectrum, infrared spectrum, NMR spectrum, etc. to the organic shrink-proofing agent extracted from the negative electrode of the battery, and the content of the organic shrink-proofing agent is measured using the ultraviolet-visible absorption spectrum.

[0134] (2-3) Sulfur element content in the organic shrinkage-proofing agent Similar to the above (2-1), after obtaining the sample B of the organic shrinkage-proofing agent, the sulfur element in 0.1 g of the organic shrinkage-proofing agent is converted into sulfuric acid by the oxygen combustion flask method. At this time, by burning the sample B in the flask containing the adsorption liquid, an eluate in which sulfate ions have dissolved in the adsorption liquid is obtained. Next, using thorin as an indicator, the eluate is titrated with barium perchlorate to determine the sulfur element content (c1) in 0.1 g of the organic shrinkage-proofing agent. Next, c1 is multiplied by 10 to calculate the sulfur element content (μmol / g) per gram of the organic shrinkage-proofing agent.

[0135] (2-4) Measurement of Mw of the organic shrinkage-proofing agent Similar to the above (2-1), after obtaining the sample B of the organic shrinkage-proofing agent, the GPC measurement of the organic shrinkage-proofing agent is carried out under the following conditions using the following equipment. Separately, a calibration curve (calibration curve) is created from the plot of Mw and elution time of the standard substance. Based on this calibration curve and the GPC measurement results of the organic shrinkage-proofing agent, the Mw of the organic shrinkage-proofing agent is calculated.

[0136] GPC device: Build-up GPC system SD-8022 / DP-8020 / AS-8020 / CO-8020 / UV-8020 (manufactured by Tosoh Corporation) Column: TSKgel G4000SWXL, G2000SWXL (7.8 mm I.D. × 30 cm) (manufactured by Tosoh Corporation) Detector: UV detector, λ = 210 nm Eluent: Mixed solution of 1 mol / L NaCl aqueous solution: acetonitrile (volume ratio = 7:3) Flow rate: 1 mL / min. Concentration: 10 mg / mL Injection volume: 10 μL Standard substance: Sodium polystyrene sulfonate (Mw = 275,000, 35,000, 12,500, 7,500, 5,200, 1,680)

[0137] (3) Quantification of carbonaceous material and barium sulfate To 10 g of the pulverized sample A, add 50 ml of nitric acid with a concentration of 20% by mass, heat for about 20 minutes, and dissolve the lead component as lead ions. Filter the resulting solution to separate solids such as carbonaceous materials and barium sulfate.

[0138] After dispersing the obtained solids in water to form a dispersion, use a sieve to remove components other than carbonaceous materials and barium sulfate (e.g., reinforcing materials) from the dispersion. Next, perform suction filtration on the dispersion using a membrane filter whose mass has been previously measured, and dry the membrane filter together with the filtered sample in a dryer at 110°C ± 5°C. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. Subtract the mass of the membrane filter from the total mass of the dried mixed sample (hereinafter referred to as sample C) and the membrane filter to measure the mass (M m ) of sample C. Then, put sample C together with the membrane filter into a crucible and incinerate it at 1300°C or higher. The remaining residue is barium oxide. Convert the mass of barium oxide to the mass of barium sulfate to obtain the mass (M B ) of barium sulfate. Subtract the mass M m from the mass M B to calculate the mass of the carbonaceous material.

[0139] (Others) The negative electrode plate can be formed by applying or filling a negative electrode paste onto a negative electrode current collector, aging and drying to produce an unformed negative electrode plate, and then forming the unformed negative electrode plate. The negative electrode paste is prepared, for example, by adding water and sulfuric acid (or an aqueous sulfuric acid solution) to lead powder, a polymer compound, and at least one selected from the group consisting of an organic shrinkage inhibitor, a carbonaceous material, and other additives, and kneading them. When aging, it is preferable to age the unformed negative electrode plate at a temperature higher than room temperature and high humidity.

[0140] Formation can be carried out, for example, by charging a plate group containing an unformed negative electrode plate and an electrolyte containing sulfuric acid in an electrolyte tank of a lead-acid battery, with the electrolyte infiltrating into the plate group. However, formation may also be carried out before assembling the lead-acid battery or the plate group. Spongy lead is generated by formation.

[0141] (Positive electrode plate) The positive electrode plates of lead-acid batteries can be classified into paste type, clad type, etc. Either paste type or clad type positive electrode plates may be used. The paste type positive electrode plate includes a positive electrode current collector and a positive electrode active material. The configuration of the clad type positive electrode plate is as described above.

[0142] 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 expand processing and punching processing. It is preferable to use a lattice-shaped current collector as the positive electrode current collector because it is easy to carry the positive electrode active material.

[0143] As the lead alloy used for the positive electrode current collector, Pb-Sb-based alloy, Pb-Ca-based alloy, and Pb-Ca-Sn-based alloy are preferable in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have 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 part, only on the ear part, or only on the frame part of the positive electrode current collector.

[0144] The positive electrode active material contained in the positive electrode plate includes a positive electrode active substance (lead dioxide or lead sulfate) that exhibits capacitance by an oxidation-reduction reaction. The positive electrode active material may contain other additives as required.

[0145] In a lead-acid battery, the density of the positive electrode active material is 3.70 g / cm 3 or more, and 3.72 g / cm 3It may be as described above. By setting the density of the positive electrode material within such a range, self-discharge can be reduced. From the perspective of synergistically reducing self-discharge, the density of the positive electrode material is preferably 3.74 g / cm 3 or more. The density of the positive electrode material is 4.65 g / cm 3 or less, and may be 4.5 g / cm 3 or less. By setting the density of the positive electrode material within such a range, self-discharge can be reduced. From the perspective of synergistically reducing self-discharge, the density of the positive electrode material is preferably 4.40 g / cm 3 or less, and more preferably 4.30 g / cm 3 or less.

[0146] The density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm 3 or less (or 4.5 g / cm 3 or less), 3.72 g / cm 3 or more and 4.65 g / cm 3 or less (or 4.5 g / cm 3 or less), 3.74 g / cm 3 or more and 4.65 g / cm 3 or less (or 4.5 g / cm 3 or less), 3.70 g / cm 3 or more and 4.40 g / cm 3 or less (or 4.30 g / cm 3 or less), 3.72 g / cm 3 or more and 4.40 g / cm 3 or less (or 4.30 g / cm 3 or less), or 3.74 g / cm 3 or more and 4.40 g / cm 3 or less (or 4.30 g / cm 3 or less) may also be acceptable.

[0147] The unformed paste-type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste and subjecting it to aging and drying. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid. The unformed clad-type positive electrode plate is formed by filling a porous tube into which a spine connected at the current collecting part is inserted with lead powder or slurry-like lead powder and joining a plurality of tubes with a spine protector. Then, these unformed positive electrode plates are formed to obtain positive electrode plates. By adjusting the amount of lead powder, the amount of water, the amount of sulfuric acid, etc. in the positive electrode paste, the density of the positive electrode material can be adjusted.

[0148] The forming can be carried out, for example, by accommodating a group of electrode plates including the unformed positive electrode plate and an electrolytic solution containing sulfuric acid in an electrolytic cell of a lead storage battery and charging the group of electrode plates in a state where the electrolytic solution has penetrated into the group of electrode plates. However, the forming may be carried out before the assembly of the lead storage battery or the group of electrode plates.

[0149] (Measurement of the density of the positive electrode material) The method for measuring the density of the positive electrode material will be described below. Prior to measurement or analysis, a fully charged lead storage battery is disassembled to obtain a positive electrode plate to be analyzed. The obtained positive electrode plate is washed with water and dried to remove the electrolytic solution in the positive electrode plate. Next, the positive electrode material is separated from near the center in the plane direction of the positive electrode plate to obtain an unground sample (sample D).

[0150] For the unground sample D, the density (bulk density) is determined by mercury intrusion porosimetry using a mercury porosimeter. More specifically, first, a predetermined amount of the unground sample D is collected and its mass is measured. This sample D is put into the measuring container of the mercury porosimeter, evacuated under reduced pressure, and then filled with mercury at a pressure of 0.5 psia or more and 0.55 psia or less (≈3.45 kPa or more and 3.79 kPa or less) to measure the bulk volume of the sample D. The density of the positive electrode material is obtained by dividing the measured mass of the sample D by the bulk volume. Note that the bulk volume is the volume obtained by subtracting the mercury injection volume from the volume of the measuring container. As the mercury porosimeter, an automatic porosimeter (AutoPore IV9505) manufactured by Shimadzu Corporation is used. When the electrode plate group includes one positive electrode plate, the density of the positive electrode material is determined for the positive electrode material collected from the positive electrode plate. When the electrode plate group includes two positive electrode plates, the density of the positive electrode material is the average value of the values determined for the positive electrode materials collected from each of the two positive electrode plates. When the electrode plate group includes three or more positive electrode plates, the density of the positive electrode material is the average value of the values determined for the positive electrode materials collected from two positive electrode plates arbitrarily selected from the positive electrode plates other than the electrode plates at both ends of the electrode plate group. However, when two of the three positive electrode plates are the electrode plates at both ends of the electrode plate group, the density of the positive electrode material is determined for the positive electrode material collected from the remaining one positive electrode plate.

[0151] (Separator) A lead-acid battery usually includes a separator interposed between a negative electrode plate and a positive electrode plate. The separator is made of a non-woven fabric. The non-woven fabric is a mat formed by intertwining fibers without weaving and mainly consists of fibers. For example, 60 mass% or more of the non-woven fabric is formed of fibers. The non-woven fabric may contain components other than fibers, such as acid-resistant inorganic powders (e.g., silica powder, glass powder, diatomaceous earth), and polymers as binders.

[0152] As the fiber, glass fiber, organic fiber, etc. can be used. As the organic fiber, a fiber material insoluble in the electrolytic solution is used. Examples of the organic fiber include polymer fibers (such as polyolefin fibers, acrylic fibers, polyester fibers (such as polyethylene terephthalate fibers, etc.)), pulp fibers, etc.

[0153] The nonwoven fabric preferably contains at least glass fiber. The nonwoven fabric containing glass fiber is also called an AGM (Absorbed Glass Mat) separator. The nonwoven fabric may contain glass fiber and organic fiber. The proportion of glass fiber in the total fibers constituting the nonwoven fabric is preferably 60% by mass or more.

[0154] The separator may be composed of only the nonwoven fabric. The separator may, if necessary, be a laminate of a nonwoven fabric and a microporous membrane, a bonded product of a nonwoven fabric and a different or the same kind of material, or a product with concavo-convex engagement of a nonwoven fabric and a different or the same kind of material, etc.

[0155] The microporous membrane is a porous sheet mainly composed of components other than fiber components. For example, it can be obtained by extruding and molding a composition containing a pore-forming agent into a sheet shape and then removing the pore-forming agent to form pores. The microporous membrane is preferably composed of a material having acid resistance, and micropores mainly composed of a polymer component are preferred. As the polymer component, polyolefin (such as polyethylene, polypropylene, etc.) is preferred. Examples of the pore-forming agent include at least one selected from the group consisting of polymer powder and oil, etc.

[0156] The thickness of the separator interposed between the negative electrode plate and the positive electrode plate may be selected according to the distance between the electrodes. The number of separator sheets may be selected according to the number of electrode intervals.

[0157] (Electrolytic solution) The electrolytic solution is an aqueous solution containing sulfuric acid and may be gelled if necessary. The above polymer compound may be contained in the electrolytic solution.

[0158] The electrolyte may contain cations (e.g., metal cations) and / or anions (e.g., anions other than sulfate anions such as phosphate ions) as required. Examples of the metal cations include at least one selected from the group consisting of Na ions, Li ions, Mg ions, and Al ions.

[0159] The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C is, for example, 1.20 or more, and may be 1.25 or more. The specific gravity of the electrolyte at 20°C is preferably 1.35 or less, and more preferably 1.32 or less.

[0160] The specific gravity of the electrolyte 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.

[0161] (Others) The lead-acid battery can be obtained by a manufacturing method including a step of accommodating a plate group and an electrolyte in a cell chamber of a battery case. Each cell of the lead-acid battery includes a plate group and an electrolyte accommodated in each cell chamber. The plate group is assembled by laminating a positive electrode plate, a negative electrode plate, and a separator such that the separator is interposed between the positive electrode plate and the negative electrode plate prior to being accommodated in the cell chamber. The positive electrode plate, the negative electrode plate, the electrolyte, and the separator are each prepared prior to the assembly of the plate group. The manufacturing method of the lead-acid battery may include a step of forming at least one of the positive electrode plate and the negative electrode plate as required after the step of accommodating the plate group and the electrolyte in the cell chamber.

[0162] Each electrode plate in the electrode plate group contained in one cell may be one or two or more. In a cell for determining the density of the positive electrode material, when the electrode plate group includes two or more negative electrode plates, in at least one negative electrode plate, the negative electrode material contains the above polymer compound, and it is preferable that the condition that the density of the positive electrode material of the cell is within the above range is satisfied. In this case, an effect of reducing self-discharge can be obtained according to the number of the negative electrode plates. From the viewpoint of further reducing self-discharge, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of negative electrode plates contained in the electrode plate group is a negative electrode plate containing the above polymer compound. Among the negative electrode plates contained in the electrode plate group, the ratio of the negative electrode plates containing the above polymer compound is 100% or less. All of the negative electrode plates contained in the electrode plate group may be negative electrode plates containing the above polymer compound.

[0163] When the lead-acid battery has two or more cells, at least the electrode plate group of the cell for determining the density of the positive electrode material needs to be provided with a negative electrode plate containing the above polymer compound. From the viewpoint of further reducing self-discharge, in 50% or more (more preferably 80% or more or 90% or more) of the number of cells contained in the lead-acid battery, the density of the positive electrode material is within the above range, and it is preferable to be provided with an electrode plate group containing a negative electrode plate containing a polymer compound. Among the cells contained in the lead-acid battery, the ratio of the cells provided with an electrode plate group in which the density of the positive electrode material is within the above range and which contains a negative electrode plate containing a polymer compound is 100% or less. It is preferable that all of the electrode plate groups contained in the lead-acid battery are provided with an electrode plate group in which the density of the positive electrode material is within the above range and which contains a negative electrode plate containing a polymer compound.

[0164] FIG. 1 is a cross-sectional view schematically showing the structure of an example of a control valve type lead-acid battery. In FIG. 1, the lead-acid battery 1 includes a battery case 10 that houses an electrode plate group 11 and an electrolytic solution (not shown). The upper opening of the battery case 10 is closed by a lid 12. The electrode plate group 11 is formed by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via separators 4, respectively.

[0165] On the upper part of each of the plurality of negative electrode plates 2, there is provided an ear portion for current collection (not shown) protruding upward. Similarly, on the upper part of each of the plurality of positive electrode plates 3, there is also provided an ear portion for current collection (not shown) protruding upward. And the ear portions of the negative electrode plates 2 are connected and integrated by a negative electrode strap (not shown). Similarly, the ear portions of the positive electrode plates 3 are also connected and integrated by a positive electrode strap (not shown). The negative electrode strap is connected to a negative electrode post (not shown) serving as an external terminal, and the positive electrode strap is connected to a positive electrode post (not shown) serving as an external terminal.

[0166] The battery case 10 is divided into a plurality (three in the illustrated example) of mutually independent cell chambers 10R, and one electrode plate group 11 is accommodated in each cell chamber 10R. The lid 12 is provided with an exhaust valve 13 independent for each cell chamber 10R. When the internal pressure of the cell chamber 10R exceeds a predetermined upper limit value, the exhaust valve 13 opens, and gas is directly discharged to the outside from the cell chamber 10R. When the internal pressure of the cell chamber 10R is below the upper limit value, oxygen generated in the positive electrode plate 3 is reduced by the negative electrode plate 2 in the same cell chamber 10R to generate water.

[0167] Note that the structure of the control valve type lead-acid battery is not limited to the above. For example, although FIG. 1 shows the case of each cell exhaust type, it may be a batch exhaust type in which the lid has a batch exhaust chamber communicating with each cell chamber, and the batch exhaust chamber is provided with a smaller number (for example, one) of exhaust valves than the number of cell chambers.

[0168] In this specification, each of the self-discharge and the low-temperature HR discharge performance is evaluated by the following procedure. The rated voltage of the test battery used for the evaluation is 12V, and the rated 10-hour rate capacity is 5Ah.

[0169] (a) Evaluation 1: Self-discharge A fully charged test battery is discharged at a discharge current of 0.5 A at 25°C ± 2°C until the terminal voltage reaches 1.75 V / cell, and the discharge capacity (initial capacity) at this time is determined. Next, the lead-acid battery is charged at 25°C ± 2°C and 0.5 A with an amount of electricity 130% of the discharge capacity until it is fully charged. The fully charged lead-acid battery is stored at 40°C ± 2°C for 30 days. The stored lead-acid battery is discharged under the same conditions as above, and the discharge capacity at this time is determined, and the decrease from the initial capacity is determined as self-discharge.

[0170] (b) Evaluation 2: Low-temperature HR discharge performance A fully charged test battery is discharged at a discharge current of 50 A at -10°C ± 2°C until the terminal voltage reaches 1.0 V / cell, and the discharge time (initial low-temperature HR discharge duration) (s) at this time is determined. The low-temperature HR discharge performance is evaluated based on this low-temperature HR discharge duration.

[0171] The lead-acid battery according to one aspect of the present invention is summarized as follows.

[0172] (1) A valve-regulated lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte, The plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate includes a negative electrode material, The negative electrode material is measured using deuterated chloroform as a solvent, 1 in the chemical shift of the 1H-NMR spectrum, contains a polymer compound having a peak in the range of 3.2 ppm or more and 3.8 ppm or less, The positive electrode plate includes a positive electrode material, The density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm 3 or less, a lead-acid battery.

[0173] (2) In the above (1), the polymer compound has an oxygen atom bonded to a terminal group and -CH bonded to the oxygen atom 2-group and / or -CH< group, and the 1 In the H-NMR spectrum, the ratio of the integral value of the peak to the sum of the integral values of the peaks of the hydrogen atoms of the -CH 2 -group and the integral value of the peak of the hydrogen atoms of the -CH< group may be 85% or more.

[0174] (3) In the above (1) or (2), the polymer compound may contain a repeating structure of an oxy C 2-4 alkylene unit.

[0175] (4) A control valve type lead-acid battery, the lead-acid battery includes at least one cell including a plate group and an electrolyte, the plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode material, the negative electrode material includes a polymer compound containing a repeating structure of an oxy C 2-4 alkylene unit, the positive electrode plate includes a positive electrode material, the density of the positive electrode material is 3.70 g / cm 3 or more and 4.65 g / cm 3 or less, a lead-acid battery.

[0176] (5) In any one of the above (1) to (4), the density of the positive electrode material may be 3.72 g / cm 3 or more, or 3.74 g / cm 3 or more.

[0177] (6) In any one of the above (1) to (5), the density of the positive electrode material may be 4.5 g / cm 3 or less, 4.40 g / cm 3 or less, or 4.30 g / cm 3 or less.

[0178] (7) In any one of (1) to (6) above, the content of the polymer compound in the negative electrode material may be 8 ppm or more, 10 ppm or more, 20 ppm or more, or 30 ppm or more on a mass basis.

[0179] (8) In any one of (1) to (7) above, the content of the polymer compound in the negative electrode material may be 1000 ppm or less, 500 ppm or less, 450 ppm or less, 420 ppm or less, 370 ppm or less, or 350 ppm or less on a mass basis.

[0180] (9) In any one of (1) to (8) above, the polymer compound may contain a compound with Mn of 5 million or less, 1 million or less, 100,000 or less, 20,000 or less, 10,000 or less, 5,000 or less, 3,000 or less, 2,500 or less, or 2,000 or less.

[0181] (10) In any one of (1) to (9) above, the polymer compound may contain a compound with Mn of 300 or more, 400 or more, or 500 or more.

[0182] (11) In any one of (1) to (10) above, the polymer compound contains at least one selected from the group consisting of a hydroxy compound having a repeating structure of oxy C 2-4 alkylene unit, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound, The hydroxy compound may be at least one selected from the group consisting of poly C 2-4 alkylene glycol, a copolymer containing a repeating structure of oxy C 2-4 alkylene, and a poly C 2-4 alkylene oxide adduct of polyol.

[0183] (12) In any one of (1) to (11) above, the polymer compound may contain a repeating structure of oxypropylene unit.

[0184] (13) In the above (12), the polymer compound may include at least one selected from the group consisting of polypropylene glycol, polyoxypropylene-polyoxyethylene copolymer (such as polyoxypropylene-polyoxyethylene block copolymer), polypropylene glycol alkyl ether (wherein R 2 is an alkyl ether (such as methyl ether, ethyl ether, butyl ether, etc.) having an alkyl group with 10 or fewer carbon atoms (or 8 or fewer or 6 or fewer carbon atoms)), polyoxyethylene-polyoxypropylene alkyl ether (wherein R 2 is an alkyl ether (such as butyl ether, hydroxyhexyl ether, etc.) having an alkyl group with 10 or fewer carbon atoms (or 8 or fewer or 6 or fewer carbon atoms)), polypropylene glycol carboxylic acid (wherein R 3 is polypropylene glycol carboxylic acid (such as polypropylene glycol acetate, etc.) having an alkyl group with 10 or fewer carbon atoms (or 8 or fewer or 6 or fewer carbon atoms)), and polypropylene oxide adducts of polyols having three or more hydroxyl groups (such as polypropylene oxide adducts of glycerin).

[0185] (14) In any one of the above (1) to (11), the polymer compound may have one or more hydrophobic groups, and at least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

[0186] (15) In the above (14), the long-chain aliphatic hydrocarbon group may have 12 or more or 16 or more carbon atoms.

[0187] (16) In the above (14) or (15), the long-chain aliphatic hydrocarbon group may have 30 or fewer, 26 or fewer or 22 or fewer carbon atoms.

[0188] (17) In any one of the above (14) to (16), the polymer compound may include a repeating structure of oxyethylene units.

[0189] (18) In the above (18), the polymer compound may include at least one selected from the group consisting of etherified products of polyethylene glycol (such as alkyl ethers), esterified products of polyethylene glycol (such as carboxylic acid esters), etherified products of polyethylene oxide adducts of the above polyols (such as alkyl ethers), and esterified products of polyethylene oxide adducts of polyols (such as triols or higher polyols) (such as carboxylic acid esters).

[0190] (19) In the above (17) or (18), the polymer compound may include at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene coconut fatty acid sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

[0191] (20) In any one of the above (17) to (19), the HLB of the polymer compound may be 4 or more, or 4.3 or more.

[0192] (21) In any one of the above (17) to (20), the HLB of the polymer compound may be 18 or less, 10 or less, 9 or less, or 8.5 or less.

[0193] (22) In any one of the above (1) to (21), the negative electrode material may include an organic anti-shrinkage agent.

[0194] (23) In any one of the above (1) to (22), the negative electrode material (or the organic anti-shrinkage agent) may include a lignin compound.

[0195] (24) In any one of the above (1) to (23), the negative electrode material (or the organic anti-shrinkage agent) may contain a condensate of a bisarene compound.

[0196] (25) In any one of the above (22) to (24), the content of the organic anti-shrinkage agent in the negative electrode material may be 0.005% by mass or more, 0.01% by mass or more, or 0.1% by mass or more.

[0197] (26) In any one of the above (22) to (25), the content of the organic anti-shrinkage agent in the negative electrode material may be 1.0% by mass or less, or 0.5% by mass or less.

[0198] (27) In any one of the above (1) to (26), the negative electrode material may contain a carbonaceous material.

[0199] (28) In the above (27), the content of the carbonaceous material in the negative electrode material may be 0.05% by mass or more, or 0.1% by mass or more.

[0200] (29) In the above (27) or (28), the content of the carbonaceous material in the negative electrode material may be 5% by mass or less, 3% by mass or less, or 1.2% by mass or less.

[0201] (30) In any one of the above (1) to (29), the negative electrode material may contain barium sulfate.

[0202] (31) In the above (30), the content of the barium sulfate in the negative electrode material may be 0.05% by mass or more, or 0.10% by mass or more.

[0203] (32) In the above (31), the content of the barium sulfate in the negative electrode material may be 3% by mass or less, or 2% by mass or less.

[0204] (33) In any one of the above (1) to (32), the specific gravity of the electrolyte in the fully charged lead-acid battery at 20°C may be 1.20 or more, or may be 1.25 or more.

[0205] (34) In any one of the above (1) to (33), the specific gravity of the electrolyte in the fully charged lead-acid battery at 20°C may be 1.35 or less, or may be 1.32 or less.

[0206] (35) In any one of the above (1) to (34), the lead-acid battery may be used for small mobility.

[0207] [Examples] 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.

[0208] 《Lead-acid batteries E1 to E34, R1 to R8, and C1 to C12》 (1) Preparation of lead-acid battery (a) Production of negative electrode plate Raw lead powder, a polymer compound shown in the table, an organic shrinkage inhibitor, a carbonaceous material (carbon black), and barium sulfate are mixed with an appropriate amount of sulfuric acid aqueous solution to obtain a negative electrode paste. At this time, the contents of the polymer compound, organic shrinkage inhibitor, and carbonaceous material in the negative electrode material, which are all obtained by the above-described procedure, become the values shown in the table, and the components are mixed so that the content of barium sulfate becomes 0.4% by mass. The negative electrode paste is filled into the mesh portion of an expanded grid made of Pb-Ca-Sn alloy, aged and dried to obtain an unformed negative electrode plate. The Mn of polypropylene glycol as the polymer compound obtained by the above-described procedure is 2000. The Mn of polyethylene glycol oleate and polyethylene glycol dilaurate used for the preparation of the negative electrode material is 500 and 630, respectively.

[0209] As the organic shrinkage inhibitor shown in the table, the following components are used. (e1) Lignin: Sodium lignosulfonate (sulfur element content 600 μmol / g, Mw 5500) (e2) Bisphenol condensate: A condensate of a bisphenol compound with an introduced sulfonic acid group and formaldehyde (sulfur element content 3330 μmol / g, Mw 9600)

[0210] (b) Preparation of the positive electrode plate The raw lead powder is mixed with an aqueous sulfuric acid solution to obtain a positive electrode paste. The positive electrode paste is filled into the mesh portion of an expanded grid made of Pb-Ca-Sn alloy, aged and dried to obtain an unformed positive electrode plate.

[0211] For a lead storage battery that is fully charged after formation, adjust the concentration and amount of the aqueous sulfuric acid solution used in the preparation of the positive electrode paste so that the density of the positive electrode material obtained by the above-described procedure becomes the value shown in the table.

[0212] (c) Preparation of the test battery The test battery has a rated voltage of 12V and a rated 10-hour rate capacity of 5Ah. The electrode plate group of the test battery is composed of 3 positive electrode plates and 4 negative electrode plates. The positive electrode plates and the negative electrode plates are alternately laminated with a separator interposed therebetween to form an electrode plate group. The electrode plate group is housed in a polypropylene battery case together with an electrolyte (aqueous sulfuric acid solution) and sealed with a lid. A fine glass mat is used as the separator. By subjecting the electrode plate group to formation in the battery case, a valve-regulated lead storage battery is manufactured. By formation, the lead storage battery becomes a fully charged state. The specific gravity of the electrolyte in the fully charged lead storage battery at 20°C is 1.32.

[0213] When the polymer compound has a repeating structure of oxyethylene units, in the 1H-NMR spectrum of the polymer compound measured by the above-described procedure, peaks derived from -CH of the oxyethylene unit are observed in the chemical shift range of 3.2 ppm or more and 3.8 ppm or less. 1 H-NMR spectrum, peaks derived from -CH of the oxyethylene unit are observed in the chemical shift range of 3.2 ppm or more and 3.8 ppm or less. 2 When the polymer compound has a repeating structure of oxypropylene units, in the 1H-NMR spectrum of the polymer compound measured by the above-described procedure, 1In the 1H-NMR spectrum, peaks derived from -CH of the oxypropylene unit are observed in the chemical shift range of 3.2 ppm or more and 3.42 ppm or less, and peaks derived from -CH and -CH of the oxypropylene unit are observed in the chemical shift range of more than 3.42 ppm and 3.8 ppm or less. Also, 2 in the 1H-NMR spectrum, the ratio of the integral value of the peak in the range of 3.2 ppm to 3.8 ppm to the total of the integral values of the peaks of the hydrogen atoms of the -CH group bonded to the oxygen atom and the integral values of the peaks of the hydrogen atoms of the -CH group bonded to the oxygen atom is 96 to 100%. 2 1 2

[0214] (2) Evaluation (a) Evaluation 1: Self-discharge For the fabricated lead-acid battery, self-discharge is evaluated according to the above-described procedure. The self-discharge of each lead-acid battery is evaluated as a ratio when the self-discharge of lead-acid battery C1 is set to 100%. The smaller this ratio, the less self-discharge and the better the performance.

[0215] (b) Evaluation 2: Low-temperature HR discharge performance For the fully charged lead-acid battery, the initial low-temperature HR discharge duration (s) is determined according to the above-described procedure. The low-temperature HR discharge performance of each lead-acid battery is evaluated as a ratio when the low-temperature HR discharge duration of lead-acid battery C1 is set to 100%. The larger this ratio, the better the low-temperature HR discharge performance.

[0216] The results are shown in Tables 1 to 5. Table 2 also shows the HLB of the polymer compound. In Tables 1, 2, 4, and 5, the difference in self-discharge from lead-acid battery C1 is shown as the self-discharge improvement rate. E1 to E34 are examples. R1 to R8 are reference examples. C1 to C12 are comparative examples.

[0217]

Table 1

[0218] ​​​As shown in Table 1, by setting the density of the positive electrode material to 3.70 - 4.65 g / cm 3 self-discharge is improved to some extent compared to the case where the density is 3.66 g / cm 3 (comparison between C1 and C2 - C6). By combining a positive electrode plate with a density of 3.70 - 4.65 g / cm 3 and a negative electrode plate provided with a negative electrode material containing a polymer compound, the effect of reducing self-discharge becomes remarkable. (Comparison between C2 - C6 and E1 - E10).

[0219] From the comparison between C1 and C2 - C6, the reduction effect of self-discharge by setting the density of the positive electrode material from 3.66 g / cm 3 to 3.70 - 4.65 g / cm 3 is 2 - 10%. Also, from the comparison between C1 and R2, the reduction effect of self-discharge by using a negative electrode plate provided with a negative electrode material containing 320 ppm of polypropylene glycol as a polymer compound by mass is 12%. For example, in E6 - E9, the self-discharge is further reduced compared to the self-discharge estimated from each of the density of the positive electrode material and the use of the polymer compound, and a synergistic effect is obtained. From the viewpoint of obtaining a synergistic effect, the density of the positive electrode material is preferably 3.74 g / cm 3 or more. From the same viewpoint, the density of the positive electrode material is preferably 4.40 g / cm 3 or less.

[0220]

Table 2

[0221] As shown in Table 2, when using a polymer compound having a repeating structure of oxyethylene units, self-discharge can be further reduced compared to the case of using polypropylene glycol (comparison between E11 - E25 and E1 - E10 in Table 1).

[0222]

Table 3

[0223] As shown in Table 3, even when the content of the polymer compound is very small, an effect of reducing self-discharge can be obtained. From the viewpoint of obtaining a higher self-discharge suppression effect, the content of the polymer compound in the negative electrode material is preferably 10 ppm or more, more preferably 20 ppm or more, or 30 ppm or more, based on mass. From the viewpoint of ensuring higher low-temperature HR discharge performance, the content of the polymer compound in the negative electrode material is preferably 370 ppm or less, more preferably 350 ppm or less, based on mass.

[0224]

Table 4

[0225] As shown in Table 4, when a condensate of a bisarene compound is used as the organic anti-shrinkage agent, there is a tendency for self-discharge to increase as compared with the case where a lignin compound is used (comparison between C1 and C7). Even when a condensate of a bisarene compound is used, similar to the case where a lignin compound is used, even if the density of the positive electrode material is adjusted within a specific range, when the negative electrode material does not contain a polymer compound, the effect of reducing self-discharge is small (comparison between C7, C8). Further, even when the negative electrode material contains a polymer compound, when the density of the positive electrode material is small, the effect of reducing self-discharge is small (comparison between C7 and R6). However, when the density of the positive electrode material is adjusted within a specific range and the negative electrode material contains a polymer compound, even when a condensate of a bisarene compound is used, self-discharge can be greatly reduced (comparison between R6 and E32). From the viewpoint of further reducing self-discharge, it is preferable to use a lignin compound.

[0226]

Table 5

[0227] As shown in Table 5, when the content of the carbonaceous material in the negative electrode material increases, self-discharge tends to increase (comparison between C1 and C9 and comparison between C7 and C11). Even when the content of the carbonaceous material in the negative electrode material is high, even if the density of the positive electrode material is increased to 4.17 g / cm 3 the effect of reducing self-discharge is relatively small (comparison between C1 and C4 and C9 and C10, comparison between C7 and C8 and C11 and C12). Also, even when the negative electrode material contains a polymer compound, if the density of the positive electrode material is small, the effect of reducing self-discharge is relatively small (comparison between C1 and R1 and C9 and R7, comparison between C7 and R6 and C11 and R8). On the other hand, when the negative electrode material contains a polymer compound and the density of the positive electrode material is adjusted to a specific range, even when the content of the carbonaceous material in the negative electrode material is high, self-discharge can be greatly reduced (E33 and E34).

Industrial Applicability

[0228] The control valve type lead storage battery is suitable for small mobility applications, idle reduction vehicle applications, industrial batteries, etc. These applications are merely examples and are not limited to these applications.

Explanation of Symbols

[0229] 1: Control valve type lead storage battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 11: Electrode plate group 10: Battery case 10R: Cell chamber 12: Cover 13: Exhaust valve

Claims

1. A lead-acid battery with a control valve, wherein the lead-acid battery comprises at least one cell including a plate group and an electrolyte, the plate group comprises a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate comprises a negative electrode material, The negative electrode material is measured using deuterochloroform as a solvent. １ In the chemical shift of the H-NMR spectrum, it contains a polymer compound having a peak in the range of 3.2 ppm or more and 3.8 ppm or less. the positive electrode plate comprises a positive electrode material, The density of the positive electrode material is 3.70 g / cm ３ or more and 4.65 g / cm ３ or less, for a lead-acid battery.

2. The polymer compound includes an oxygen atom bonded to a terminal group, and a —CH ２ — group and / or a —CH< group bonded to the oxygen atom, In the １ H-NMR spectrum, the ratio of the integrated value of the peak to the total of the integrated value of the peak of the hydrogen atom of the -CH ２ - group and the integrated value of the peak of the hydrogen atom of the -CH< group is 85% or more. The lead storage battery according to claim 1.

3. The polymer compound contains an oxy C ２－４ The lead storage battery according to claim 1 or 2, including a repeating structure of an alkylene unit.

4. A lead-acid battery with a control valve, wherein the lead-acid battery comprises at least one cell including a plate group and an electrolyte, the plate group comprises a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate comprises a negative electrode material, The negative electrode material includes oxy-C ２－４ a polymer compound including a repeating structure of an alkylene unit, the positive electrode plate comprises a positive electrode material, The density of the positive electrode material is 3.70 g / cm ３ or more and 4.65 g / cm ３ or less, a lead storage battery.

5. The density of the positive electrode material is 3.74 g / cm ３ or more and 4.40 g / cm ３ or less. The lead storage battery according to any one of claims 1 to 4.

6. The lead-acid battery according to any one of Claims 1 to 5, wherein the content of the polymer compound in the negative electrode material is 10 ppm or more on a mass basis.

7. The lead-acid battery according to any one of Claims 1 to 6, wherein the content of the polymer compound in the negative electrode material is 370 ppm or less on a mass basis.

8. The polymer compound contains at least one selected from the group consisting of a hydroxy compound having a repeating structure of oxy C ２－４ alkylene units, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound. The hydroxy compound is poly C ２－４ alkylene glycol, oxy C ２－４ a copolymer containing a repeating structure of alkylene, and poly C of polyol ２－４ The lead storage battery according to any one of claims 1 to 7, which is at least one selected from the group consisting of an alkylene oxide adduct.

9. The lead-acid battery according to any one of Claims 1 to 8, wherein the polymer compound includes a repeating structure of oxypropylene units.

10. The lead-acid battery according to Claim 8, wherein the polymer compound has one or more hydrophobic groups, and at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

11. The lead-acid battery according to Claim 8 or 10, wherein the polymer compound includes a repeating structure of oxyethylene units.

12. The lead-acid battery according to any one of Claims 1 to 11, which is used for small mobility.

13. The lead-acid battery according to any one of Claims 1 to 12, wherein the negative electrode material includes a lignin compound.

14. The lead-acid battery according to any one of Claims 1 to 13, wherein the negative electrode material includes a condensate of a bisarene compound.

15. The negative electrode material includes a carbonaceous material, and the content of the carbonaceous material in the negative electrode material is 0.1% by mass or more and 1.2% by mass or less. The lead-acid battery according to any one of Claims 1 to 14.

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