lead-acid batteries

Abstract

A lead-acid battery is provided with at least one cell that is provided with an electrode plate group and an electrolyte solution. The electrode plate group is provided with a negative electrode plate, a positive electrode plate, and a bag-shaped separator that is interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate is provided with a negative electrode current collector and a negative electrode material. The positive electrode plate is provided with a positive electrode current collector and a positive electrode material. The negative electrode material comprises a polymer compound having a peak in the range of 3.2-3.8 ppm for the chemical shift in the 1H–NMR spectrum measured using deuterated chloroform as solvent. The positive electrode current collector contains Sn. The bag-shaped separator is provided with a rib protruding toward the positive electrode plate and houses the positive electrode plate.

Description

[Technical Field]

[0001] The present invention relates to a lead-acid battery. [Background technology]

[0002] Lead-acid batteries are used in a variety of applications, including automotive and industrial applications. Lead-acid batteries include negative and positive plates, separators (or mats), and electrolytes. Each plate includes a current collector and an electrode material.

[0003] In order to impart various functions to lead-acid batteries, additives are sometimes added to the components of lead-acid batteries.

[0004] Patent Document 1 proposes a lead-acid battery characterized in that the electrolyte and / or the electrode active material molded body contains a polymer compound containing any one selected from the group consisting of polyvinyl alcohol, polyethylene glycol, polyvinylpyrrolidone, polyacrylic acid, or esters thereof, each having a degree of polymerization of 30 to 3000, or the polymer compound and colloidal barium sulfate particles.

[0005] Patent Document 2 proposes a negative electrode plate for a lead-acid battery, in which a paste-type active material containing a shrinkage inhibitor is filled into a current collector, and the shrinkage inhibitor is polyoxyperfluoroethylenephenylamine represented by a specific chemical formula, and the polyoxyperfluoroethylenephenylamine is contained in an amount of 0.005 to 3% by weight relative to the paste-type active material.

[0006] In addition to sheet or mat-like separators, pouch-like separators may also be used. For example, Patent Document 3 proposes a lead-acid battery in which a positive electrode plate, in which a paste-like active material is filled in a grid of a lead-calcium-tin (Pb-Ca-Sn) alloy containing 0.05 to 0.07 wt % of calcium (Ca) and 0.75 to 1.0 wt % of tin (Sn), is housed in a pouch-like separator made by folding a microporous polyethylene film into a U-shape, providing vertically parallel ribs on the inside, and providing mechanical irregularities on both the left and right ends and crimping them together. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-149981 [Patent Document 2] Japanese Patent Application Publication No. 9-147874 [Patent Document 3] Japanese Patent Application Publication No. 5-307949 Summary of the Invention [Problem to be solved by the invention]

[0008] Repeated charge / discharge cycles of lead-acid batteries cause the positive electrode current collector to elongate due to corrosion. Therefore, if the positive electrode plate is housed in a pouch-shaped separator, the separator breaks and a short circuit occurs, shortening the battery's life. In particular, during high-temperature cycle tests, the positive electrode current collector elongates significantly, significantly reducing the battery's lifespan. However, it was found that housing the positive electrode plate in a pouch-shaped separator improves the battery's lifespan during deep discharge cycle tests. [Means for solving the problem]

[0009] A first aspect of the present disclosure is a lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is measured using deuterated chloroform as a solvent. 1 The polymer compound has a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of the H-NMR spectrum, the positive electrode current collector contains Sn, The lead-acid battery relates to the pouch-shaped separator, which has ribs protruding toward the positive electrode plate and houses the positive electrode plate.

[0010] A second aspect of the present invention is a lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is oxy C 2-4 The polymer compound includes a repeating structure of an alkylene unit, the positive electrode current collector contains Sn, The lead-acid battery relates to the pouch-shaped separator, which has ribs protruding toward the positive electrode plate and houses the positive electrode plate. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partially cutaway exploded perspective view showing the appearance and internal structure of a lead-acid battery according to one aspect of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] In deep discharge cycle tests, which involve repeated charge and discharge, including deep discharge, lead-acid batteries are prone to stratification, where the electrolyte density is low in the upper part and high in the lower part. As stratification progresses, lead sulfate is more likely to accumulate in the lower part of the electrode plate. When the accumulation of lead sulfate becomes significant, a phenomenon known as sulfation occurs, in which the accumulated lead sulfate becomes difficult to reduce even when the battery is charged. Meanwhile, because charge and discharge reactions are more likely to occur on the upper side of the electrode plate, softening of the positive electrode material becomes more pronounced in the upper part of the positive plate. As a result, the lifespan of lead-acid batteries is reduced.

[0013] To prevent stratification, it is effective to reduce the difference in specific gravity of the electrolyte near the negative electrode plate. Therefore, it has been considered advantageous to house the negative electrode in a pouch-shaped separator. Furthermore, repeated charging and discharging of a lead-acid battery causes the positive electrode current collector to elongate due to corrosion. The elongation of the positive electrode current collector is particularly pronounced when repeated charging and discharging are performed at high temperatures (such as in a high-temperature cycle test). Furthermore, when a positive electrode plate is housed in a pouch-shaped separator, oxidation degradation of the separator is more likely to progress than when a negative electrode plate is housed, making the separator more susceptible to breakage. Therefore, from the perspective of avoiding short circuits due to breakage of the pouch-shaped separator, it is advantageous to house the negative electrode plate in a pouch-shaped separator.

[0014] However, it has been found that housing a positive electrode plate in a pouch-shaped separator unexpectedly suppresses stratification and improves battery life in deep discharge cycle tests. However, as described above, the positive electrode current collector elongates significantly in high-temperature cycle tests, and housing a positive electrode plate in a pouch-shaped separator results in separator damage and a shortened battery life. Thus, when housing a positive electrode plate in a pouch-shaped separator, it is difficult to achieve both high life performance in deep discharge cycle tests and high life performance in high-temperature cycle tests.

[0015] In view of the above, a lead-acid battery according to a first aspect of the present invention is a lead-acid battery comprising at least one cell comprising an electrode plate assembly and an electrolyte. The electrode plate assembly comprises a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate comprises a negative electrode current collector and a negative electrode material. The positive electrode plate comprises a positive electrode current collector and a positive electrode material. The negative electrode material is measured using deuterated chloroform as a solvent. 1 The battery contains a polymer compound having a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of its H-NMR spectrum. The positive electrode current collector contains Sn. The pouch-shaped separator has ribs protruding toward the positive electrode plate and houses the positive electrode plate. In addition, the above 1 In the H-NMR spectrum, the peaks appearing in the chemical shift range of 3.2 ppm to 3.8 ppm are oxy-C 2-4 It is derived from an alkylene unit.

[0016] A lead-acid battery according to a second aspect of the present invention is a lead-acid battery comprising at least one cell comprising an electrode plate assembly and an electrolyte. The electrode plate assembly comprises a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate comprises a negative electrode current collector and a negative electrode material. The positive electrode plate comprises a positive electrode current collector and a positive electrode material. The negative electrode material comprises oxy-C 2-4 The positive electrode current collector includes a polymer compound having a repeating structure of alkylene units. The positive electrode current collector includes Sn. The pouch-shaped separator has ribs protruding toward the positive electrode plate and houses the positive electrode plate.

[0017] In the lead-acid batteries according to the first and second aspects of the present invention, the negative electrode material contains the polymer compound as described above, and the positive electrode plate including the positive electrode current collector containing Sn is housed in a pouch-shaped separator with ribs protruding toward the positive electrode plate. This configuration ensures excellent life performance in both deep discharge cycle tests and high-temperature cycle tests.

[0018] The reason why the lead-acid batteries according to the first and second aspects of the present invention can ensure excellent life performance in both the deep discharge cycle test and the high temperature cycle test is believed to be as follows.

[0019] During charging, lead-acid batteries release a large amount of sulfate ions from the electrodes. This concentration difference with the low sulfate ion concentration in the electrolyte causes convection, reducing the concentration difference. If the negative electrode material contains a polymer compound, charge acceptance decreases, making it difficult to reduce the sulfate ion concentration difference. Because oxidation degradation of the separator becomes more pronounced where it contacts the positive electrode plate, the separator is sometimes provided with ribs that protrude toward the positive electrode plate. The ribs allow the electrolyte to convect through the space formed between the positive electrode plate and the separator. Therefore, when a pouch-shaped separator houses the negative electrode plate, the electrolyte, which has a high sulfate ion concentration, tends to pass through the space between the separator and the positive electrode plate and settle to the bottom of the battery container, below the electrode plate. In contrast, the lead-acid batteries of the first and second aspects house the positive electrode plate in a pouch-shaped separator. As a result, even if an electrolyte with a high sulfate ion concentration settles through the space between the positive electrode plate and the separator, the bottom of the pouch-shaped separator prevents it from settling further downward. Because many sulfate ions are present near the electrode plate, even if a difference in sulfate ion concentration occurs, the difference in concentration is easily reduced by convection. Therefore, stratification is reduced in deep discharge cycle tests, ensuring excellent life performance.

[0020] In high-temperature cycle tests, the elongation of the positive electrode plate due to corrosion of the positive electrode current collector generally becomes significant. In the lead-acid batteries of the first and second aspects, the positive electrode current collector contains Sn, which precipitates at the grain boundaries of lead, reducing corrosion of the positive electrode current collector. Furthermore, the negative electrode material contains a polymer compound, which increases the hydrogen overvoltage in the negative electrode plate and reduces the charging current value during constant-voltage charging. This makes it difficult for corrosion of the positive electrode current collector to progress. Furthermore, when the polymer compound eluted from the negative electrode plate adheres to the separator, it acts as an antioxidant, reducing oxidative degradation of the separator and making it less susceptible to breakage. These factors are thought to synergistically reduce corrosion of the positive electrode current collector and reduce oxidative degradation of the separator, thereby synergistically improving life performance in high-temperature cycle tests.

[0021] From the viewpoint of enhancing the effect of inhibiting corrosion of the positive electrode current collector and further improving the life performance in a high-temperature cycle test, the Sn content in the positive electrode current collector is preferably 0.5 mass % or more.

[0022] The Sn content in the positive electrode current collector is preferably less than 3% by mass. At this Sn content range, the effect of elongation due to corrosion of the positive electrode current collector becomes apparent. However, by configuring the negative electrode material to contain a polymer compound, a positive electrode plate including a positive electrode current collector with an Sn content of less than 3% by mass can be housed in a pouch-shaped separator, ensuring high life performance in a high-temperature cycle test.

[0023] The effect of the polymer compound in increasing hydrogen overvoltage is exerted by covering the surface of lead with the polymer compound. Therefore, it is important that the polymer compound be present in the vicinity of lead, which allows the effect of the polymer compound to be exerted effectively. Therefore, it is important that the negative electrode material contains a polymer compound, regardless of whether or not a polymer compound is contained in components of a lead-acid battery other than the negative electrode material.

[0024] In the lead-acid battery of the first aspect, the polymer compound may include oxygen atoms bonded to end groups and -CH2- groups and / or -CH< groups bonded to the oxygen atoms. 1 In the H-NMR spectrum, the ratio of the integral value of the peaks between 3.2 ppm and 3.8 ppm to the total integral value of the peaks between 3.2 ppm and 3.8 ppm, the integral value of the peaks of the hydrogen atoms of the -CH2- groups bonded to the oxygen atoms, and the integral value of the peaks of the hydrogen atoms of the -CH< groups bonded to the oxygen atoms is preferably 85% or more. 2-4 The polymer compound contains many alkylene units in its molecule. This makes it easier for the polymer compound to adsorb to lead and also makes it easier for it to adopt a linear structure, which is thought to make it easier to thinly coat the lead surface. This increases the hydrogen overvoltage and suppresses a decrease in charge acceptance, further improving life performance in deep discharge cycle tests and high-temperature cycle tests.

[0025] 1 Polymer compounds with peaks in the chemical shift range of 3.2 ppm to 3.8 ppm in the H-NMR spectrum are oxy-C 2-4 It is preferable that the alkylene unit contains a repeating structure. 2-4 When a polymer compound containing a repeating alkylene unit structure is used, it is believed that the polymer compound is more easily adsorbed to lead and that the linear structure makes it easier to thinly coat the lead surface, thereby increasing the hydrogen overvoltage and suppressing the decrease in charge acceptance, thereby further improving the life performance in deep discharge cycle tests and high-temperature cycle tests.

[0026] The polymer compound is OxyC 2-4 The hydroxy compound 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 a hydroxy compound, and an esterified product of a hydroxy compound. 2-4 Alkylene glycol, oxy C 2-4Copolymers containing repeating alkylene units and polyol polyC 2-4 The polymer compound is at least one selected from the group consisting of alkylene oxide adducts. When such a polymer compound is used, the effect of increasing hydrogen overvoltage is further enhanced and a decrease in charge acceptance can be suppressed, thereby ensuring higher life performance in deep discharge cycle tests and high-temperature cycle tests.

[0027] The polymer compound may contain a repeating structure of an oxypropylene unit (-O-CH(-CH3)-CH2-). Such a polymer compound tends to have lower charge acceptance than a polymer compound containing a repeating structure of an oxyethylene unit (-O-CH2-CH2-). However, by including Sn in the positive electrode current collector and housing the positive electrode plate in a pouch-shaped separator, it is possible to ensure high life performance in deep discharge cycle tests and high-temperature cycle tests.

[0028] 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. The action of such hydrophobic groups prevents excessive coating of the polymer compound on the lead surface, further enhancing the effect of suppressing a decrease in charge acceptance. The polymer compound preferably contains a repeating structure of oxyethylene units. By containing a repeating structure of oxyethylene units with high hydrophilicity, the polymer compound can be selectively adsorbed to lead. The balance between the hydrophobic and hydrophilic groups can increase hydrogen overvoltage and suppress a decrease in charge acceptance, thereby further improving life performance in deep discharge cycle tests and high-temperature cycle tests.

[0029] The HLB of the polymer compound is preferably 4 or more and 9 or less. In this case, the balance between hydrophobicity and hydrophilicity can increase the hydrogen overvoltage and suppress a decrease in charge acceptance, thereby further improving the life performance in deep discharge cycle tests and high-temperature cycle tests.

[0030] Thus, the polymer compound has high adsorption properties for lead while being able to thinly coat the lead surface, so even if the content of the polymer compound in the negative electrode material is small, it can increase the hydrogen overvoltage and suppress a decrease in charge acceptance. From the viewpoint of further enhancing the effect of suppressing a decrease in charge acceptance and ensuring a longer life performance in a deep discharge cycle test, the content of the polymer compound in the negative electrode material is preferably 550 ppm or less by mass. From the viewpoint of enhancing the effect of increasing the hydrogen overvoltage and ensuring a longer life performance in a high-temperature cycle test, the content of the polymer compound in the negative electrode material is preferably 5 ppm or more.

[0031] In a lead-acid battery, the origin of the polymer compound contained in the negative electrode material is not particularly limited as long as the polymer compound can be contained in the negative electrode material. When producing a lead-acid battery, the polymer compound may be contained in any of the components of the lead-acid battery (e.g., the negative electrode plate, the positive electrode plate, the electrolyte, and the separator). The polymer compound may be contained in one component, or in two or more components (e.g., the negative electrode plate and the electrolyte).

[0032] The lead acid battery may be either a valve regulated (sealed) lead acid battery (VRLA type lead acid battery) or a flooded (vented) lead acid battery.

[0033] In this specification, the content of the polymer compound in the negative electrode material and the content of Sn in the positive electrode current collector are determined for a negative electrode plate or a positive electrode plate removed from a fully charged lead-acid battery.

[0034] (Terminology explanation) (electrode material) The negative electrode material and the positive electrode material are usually held by a current collector. The electrode material is the portion of the electrode plate excluding the current collector. A mat, pasting paper, or other member may be attached to the electrode plate. Such members (also called attachment members) are used integrally with the electrode plate and are therefore included in the electrode plate. When the electrode plate includes an attachment member (such as a mat or pasting paper), the electrode material is the portion of the electrode plate excluding the current collector and attachment member.

[0035] (polymer compound) The polymer compound satisfies at least one of the following conditions (i) and (ii): Condition (i) Polymer compounds are measured using deuterated chloroform as a solvent. 1 In the chemical shift of the H-NMR spectrum, it has a peak in the range of 3.2 ppm to 3.8 ppm. Condition (ii) The polymer compound is OxyC 2-4 It contains a repeating structure of alkylene units.

[0036] Under condition (i), the peak in the range of 3.2 ppm to 3.8 ppm is oxy-C. 2-4 The polymer compounds satisfying the condition (ii) are derived from alkylene units. In other words, the polymer compounds satisfying the condition (i) are also polymer compounds satisfying the condition (i). The polymer compounds satisfying the condition (i) are derived from oxy C 2-4 The polymer compound may contain a repeating structure of a monomer unit other than an alkylene unit, as long as it has a certain molecular weight. The number average molecular weight (Mn) of a polymer compound satisfying the above (i) or (ii) may be, for example, 300 or more.

[0037] (Oxy C 2-4 alkylene unit) Oxy C 2-4 The alkylene unit is -OR 1 -(R 1 is C 2-4 It is a unit represented by the formula (1).

[0038] (HLB) HLB stands for Hydrophile Lipophile Balance, and is a value that indicates the balance between hydrophobicity and hydrophilicity of a surfactant (mainly a nonionic surfactant). The HLB value of a polymer compound (P) is determined by the Griffin method.

[0039] (number average molecular weight) In this specification, the number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used to determine Mn is polyethylene glycol.

[0040] (fully charged) The fully charged state of a flooded lead-acid battery is defined by JIS D 5301:2019. More specifically, a fully charged state is defined as a state in which a lead-acid battery is charged in a water tank at 25°C ± 2°C with a current (A) 0.2 times the rated capacity (unit: Ah) until the terminal voltage (V) during charging or the electrolyte density converted to 20°C temperature shows a constant value to three significant digits three times consecutively. For a valve-regulated lead-acid battery, a fully charged state is defined as a state in which a battery is charged in an air tank at 25°C ± 2°C with a constant current / constant voltage of 2.23 V / cell with a current (A) 0.2 times the rated capacity (unit: Ah), and charging is terminated when the charging current during constant voltage charging reaches a value (A) 0.005 times the rated capacity (unit: Ah).

[0041] A fully charged lead-acid battery refers to a lead-acid battery that has already been chemically formed and is fully charged. A lead-acid battery can be fully charged immediately after chemical formation, or after some time has passed since chemical formation (for example, a lead-acid battery that has been in use (preferably in the early stages of use) after chemical formation can be fully charged). A battery in the early stages of use refers to a battery that has not been in use for very long and has hardly deteriorated at all.

[0042] (Top and bottom directions of lead-acid batteries or components of lead-acid batteries) In this specification, the up-down direction of a lead-acid battery or its components (such as plates, a battery case, and a separator) refers to the up-down direction in the vertical direction of the lead-acid battery when the battery is in use. Each of the positive and negative plates has a lug for connecting to an external terminal. In some cases, such as horizontally placed valve-regulated lead-acid batteries, the lug is provided on the side of the plate so as to protrude laterally, but in most lead-acid batteries, the lug is usually provided on the top of the plate so as to protrude upward.

[0043] Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described in detail for each of its main components, but the present invention is not limited to the following embodiment.

[0044] [Lead acid battery] (negative plate) The negative electrode plate usually includes a negative electrode current collector in addition to a negative electrode material.

[0045] (Negative electrode current collector) The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or by processing a lead sheet or a lead alloy sheet. Examples of processing methods include expanding and punching. A lattice-shaped current collector is preferably used as the negative electrode current collector because it is easy to support the negative electrode material.

[0046] The lead alloy used for the negative electrode current collector may be any of a Pb-Sb alloy, a Pb-Ca alloy, and a Pb-Ca-Sn alloy. These lead or lead alloys may further contain at least one additive element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, and the like. The negative electrode current collector may have a surface layer. The surface layer and the inner layer of the negative electrode current collector may have different compositions. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on an edge portion of the negative electrode current collector. The surface layer of the edge portion may contain Sn or an Sn alloy.

[0047] (Negative electrode material) The negative electrode material includes the polymer compound. The negative electrode material further includes a negative electrode active material (specifically, lead or lead sulfate) that exhibits capacity through a redox reaction. The negative electrode material may include at least one selected from the group consisting of an organic shrinkage inhibitor, a carbonaceous material, and other additives. Examples of additives include, but are not limited to, barium sulfate and fibers (such as resin fibers). Note that the negative electrode active material in a charged state is sponge lead, but unformed negative plates are usually made using lead powder.

[0048] (polymer compound) The polymer compound is 1 In the chemical shift of the H-NMR spectrum, the peak is in the range of 3.2 ppm to 3.8 ppm. 2-4 Contains alkylene units. OxyC 2-4 Examples of the alkylene unit include an oxyethylene unit, an oxypropylene unit, an oxytrimethylene unit, an oxy2-methyl-1,3-propylene unit, an oxy1,4-butylene unit, and an oxy1,3-butylene unit. 2-4 The alkylene unit may have one type or two or more types.

[0049] The polymer compound is OxyC 2-4 It is preferred that the repeating unit contains a repeating alkylene unit. 2-4 may contain alkylene units, and two or more oxy C 2-4 The polymer compound may contain one type of repeating structure or two or more types of repeating structures.

[0050] Oxy C 2-4 Polymer compounds having a repeating structure of alkylene units also include polymer compounds classified as surfactants (more specifically, nonionic surfactants).

[0051] Examples of polymer compounds include oxy C 2-4 Hydroxy compounds with repeating alkylene units (polyC 2-4 Alkylene glycol, oxy C 2-4 Copolymer containing repeating alkylene units, polyol polyC 2-4 alkylene oxide adducts, ethers or esters of these hydroxy compounds, etc.

[0052] As copolymers, different oxy C 2-4 The copolymer may be a block copolymer.

[0053] The polyol may be any of aliphatic polyols, alicyclic polyols, aromatic polyols, and heterocyclic polyols. From the viewpoint of facilitating thin spreading of the polymer compound on the lead surface, aliphatic polyols and alicyclic polyols (e.g., polyhydroxycyclohexane, polyhydroxynorbornane) are preferred, and aliphatic polyols are particularly preferred. Examples of aliphatic polyols include aliphatic diols and polyols with triols or more (e.g., glycerin, trimethylolpropane, pentaerythritol, sugars, or sugar alcohols). Examples of aliphatic diols include alkylene glycols with 5 or more carbon atoms. Examples of alkylene glycols include C 5~14 Alkylene glycol or C 5-10 The sugar or sugar alcohol may be, for example, sucrose, erythritol, xylitol, mannitol, or sorbitol. The sugar or sugar alcohol may have either a linear structure or a cyclic structure. In the polyalkylene oxide adduct of polyol, the alkylene oxide is an oxy-C of the polymer compound. 2-4 Corresponding to an alkylene unit, at least C 2-4 The polyol contains an alkylene oxide. From the viewpoint that the polymer compound is likely to have a linear structure, the polyol is preferably a diol.

[0054] The etherified product is the above-mentioned oxy C 2-4 At least some of the terminal -OH groups (-OH groups consisting of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom) of the hydroxy compound having a repeating structure of alkylene units are etherified to form -OR 2 group (wherein R 2 is an organic group.) Some or all of the terminals of the polymer compound may be etherified. For example, one terminal of the main chain of a linear polymer compound is an -OH group and the other terminal is an -OR group. 2 It may also be a group.

[0055] The esterified product is the above-mentioned oxy C 2-4 At least some of the terminal -OH groups (-OH groups consisting of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom) of a hydroxy compound having a repeating structure of alkylene units are esterified to form -OC(=O)-R 3 group (wherein R 3 is an organic group.) Some or all of the terminals of the polymer compound may be esterified. For example, one terminal of the main chain of a linear polymer compound is an -OH group and the other terminal is an -OC(=O)-R 3 It may also be a group.

[0056] organic group R 2 and R 3 Each of the groups includes a hydrocarbon group. The hydrocarbon group may have 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 in the aliphatic hydrocarbon group as a substituent may be, for example, 1 to 30, 1 to 20, 1 to 10, 1 to 6, or 1 to 4.

[0057] Examples of aromatic hydrocarbon groups include aromatic hydrocarbon groups having 24 or less carbon atoms (e.g., 6 to 24). The number of carbon atoms in the aromatic hydrocarbon group may be 20 or less (e.g., 6 to 20), 14 or less (e.g., 6 to 14), or 12 or less (e.g., 6 to 12). Examples of aromatic hydrocarbon groups include aryl groups and bisaryl groups. Examples of aryl groups include phenyl groups and naphthyl groups. Examples of bisaryl groups include monovalent groups corresponding to bisarenes. Examples of bisarenes include biphenyl and bisarylalkanes (e.g., bisC 6-10 Aryl C 1-4 Alkanes (such as 2,2-bisphenylpropane) are examples.

[0058] Examples of alicyclic hydrocarbon groups include alicyclic hydrocarbon groups having 16 or less carbon atoms. The alicyclic hydrocarbon group may be a bridged cyclic hydrocarbon group. The number of carbon atoms in the alicyclic hydrocarbon group may be 10 or less or 8 or less. The number of carbon atoms in the alicyclic hydrocarbon group may be, for example, 5 or more, or 6 or more.

[0059] The alicyclic hydrocarbon group may have 5 (or 6) or more and 16 (or less), 5 (or 6) or more and 10 (or less), or 5 (or 6) or more and 8 (or less) carbon atoms.

[0060] Examples of alicyclic hydrocarbon groups include cycloalkyl groups (cyclopentyl, cyclohexyl, cyclooctyl, etc.) and cycloalkenyl groups (cyclohexenyl, cyclooctenyl, etc.). Alicyclic hydrocarbon groups also include hydrogenated products of the above aromatic hydrocarbon groups.

[0061] Among hydrocarbon groups, aliphatic hydrocarbon groups are preferred from the viewpoint of facilitating thin adhesion of the polymer compound to the lead surface. 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, and a trienyl group having three carbon-carbon double bonds. The aliphatic hydrocarbon group may be either linear or branched.

[0062] The number of carbon atoms in the aliphatic hydrocarbon group is, for example, 30 or less, and may be 26 or 22 or less, 20 or 16 or less, 14 or 10 or less, or 8 or 6 or less. The lower limit of the number of carbon atoms depends on the type of aliphatic hydrocarbon group: 1 or more for alkyl groups, 2 or more for alkenyl groups and alkynyl groups, 3 or more for dienyl groups, and 4 or more for trienyl groups. Among these, alkyl and alkenyl groups are preferred from the viewpoint of facilitating thin adhesion of the polymer compound to the lead surface.

[0063] Specific examples of alkyl groups 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, and behenyl.

[0064] Specific examples of the alkenyl group include vinyl, 1-propenyl, allyl, cis-9-heptadecen-1-yl, palmitoleyl, and oleyl. 2-30 Alkenyl group or C 2-26 may be an alkenyl group, C 2-22 Alkenyl group or C 2-20 may be an alkenyl group, C 10-20 It may also be an alkenyl group.

[0065] Among polymer compounds, oxy C 2-4 Ethers of hydroxy compounds with repeating alkylene units and oxy-C 2-4 The use of at least one selected from the group consisting of esters of hydroxy compounds having a repeating alkylene unit structure is preferred because it can further suppress the decrease in charge acceptance and further improve the life performance in a high-temperature cycle test. Furthermore, the use of these polymer compounds can also ensure the effect of increasing hydrogen overvoltage. Among these polymer compounds, a polymer compound having a repeating oxypropylene unit structure or a polymer compound having a repeating oxyethylene unit structure is preferred.

[0066] The polymer compound may have one or more hydrophobic groups. Examples of the hydrophobic group include, among the above-mentioned hydrocarbon groups, aromatic hydrocarbon groups, alicyclic hydrocarbon groups, and long-chain aliphatic hydrocarbon groups. Examples of the long-chain aliphatic hydrocarbon group include, among the above-mentioned aliphatic hydrocarbon groups (such as alkyl groups and alkenyl groups), aliphatic hydrocarbon groups having 8 or more carbon atoms. The number of carbon atoms in the aliphatic hydrocarbon group is preferably 12 or more, more preferably 16 or more. Among these, polymer compounds having long-chain aliphatic hydrocarbon groups are preferred because they are less likely to cause excessive adsorption of lead and further enhance the effect of suppressing a decrease in charge acceptance. 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 in the long-chain aliphatic hydrocarbon group may be 30 or less, 26 or less, or 22 or less.

[0067] The long-chain aliphatic hydrocarbon group may have 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 carbon atoms.

[0068] Among polymer compounds, polymer compounds having both hydrophilic and hydrophobic groups correspond to nonionic surfactants. The repeating structure of oxyethylene units exhibits high hydrophilicity and can serve as the hydrophilic group in nonionic surfactants. Therefore, it is preferable that the polymer compound having the hydrophobic group contains a repeating structure of oxyethylene units. Such polymer compounds selectively adsorb lead while preventing excessive coverage of the lead surface due to the balance between hydrophobicity and high hydrophilicity resulting from the repeating structure of oxyethylene units, thereby increasing hydrogen overvoltage and further enhancing the effect of suppressing a decrease in charge acceptance. Such polymer compounds can ensure high adsorption to lead even with a relatively low molecular weight (e.g., Mn of 1000 or less).

[0069] Among the above polymer compounds, polyoxypropylene-polyoxyethylene block copolymers, etherified products of hydroxy compounds having a repeating structure of oxyethylene units, and esterified products of hydroxy compounds having a repeating structure of oxyethylene units correspond to nonionic surfactants.

[0070] In polyoxypropylene-polyoxyethylene block copolymers, the repeating structure of oxyethylene units corresponds to the hydrophilic group, and the repeating structure of oxypropylene units corresponds to the hydrophobic group. Such copolymers are also included in polymer compounds having hydrophobic groups.

[0071] Examples of polymer compounds having a hydrophobic group and a repeating structure of oxyethylene units include etherified polyethylene glycol (e.g., alkyl ethers), esterified polyethylene glycol (e.g., carboxylic acid esters), etherified polyethylene oxide adducts of the above polyols (e.g., alkyl ethers), and esterified polyethylene oxide adducts of the above polyols (e.g., triols or higher polyols) (e.g., carboxylic acid esters). Specific examples of such polymer compounds include, but are not limited to, 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. Among these, esterified polyethylene glycol and esterified polyethylene oxide adducts of the above polyols are preferred because they can ensure higher charge acceptance and increase hydrogen overvoltage.

[0072] Among polymer compounds, polymer compounds classified as surfactants have an increased effect of increasing hydrogen overvoltage and are more likely to ensure a longer life in a high-temperature cycle test, so that the HLB of the polymer compound is preferably 4 or more, more preferably 4.3 or more. From the viewpoint of ensuring higher charge acceptance and thus a longer life in a deep discharge cycle test, the HLB of the polymer compound is preferably 18 or less, more preferably 10 or less or 9 or less, and even more preferably 8.5 or less.

[0073] 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 achieving an excellent balance between the life performance in a high-temperature cycle life test and the life performance in a deep discharge cycle test, 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.

[0074] Oxy C 2-4 It is also preferable that the repeating alkylene unit contains at least a repeating oxypropylene unit. In this case, the charge acceptance tends to be lower than when the repeating oxyethylene unit is contained, but even in this case, high life performance can be ensured in deep discharge cycle tests and high temperature cycle tests. The polymer compound containing the oxypropylene unit is 1 In the chemical shift of the H-NMR spectrum, peaks due to -CH< and -CH2- of the oxypropylene unit are present in the range of 3.2 ppm to 3.8 ppm. The peaks are split due to differences in electron density around the nuclei of the hydrogen atoms in these groups. Such polymer compounds are 1 In the chemical shift of the H-NMR spectrum, for example, there are peaks in the range of 3.2 ppm to 3.42 ppm and in the range of more than 3.42 ppm to 3.8 ppm. The peak in the range of 3.2 ppm to 3.42 ppm is derived from -CH2-, and the peak in the range of more than 3.42 ppm to 3.8 ppm is derived from -CH< and -CH2-.

[0075] Examples of polymer compounds containing at least a repeating structure of oxypropylene units include polypropylene glycol, copolymers containing a repeating structure of oxypropylene units, polypropylene oxide adducts of the above polyols, and etherified or esterified products thereof. Examples of copolymers include oxypropylene-oxyalkylene copolymers (wherein the oxyalkylene is a C alkylene other than oxypropylene). 2-4Examples of the oxypropylene-oxyalkylene copolymer include an oxypropylene-oxyethylene copolymer and an oxypropylene-oxytrimethylene copolymer. The oxypropylene-oxyalkylene copolymer is sometimes referred to as a polyoxypropylene-polyoxyalkylene copolymer (e.g., a polyoxypropylene-polyoxyethylene copolymer). The oxypropylene-oxyalkylene copolymer may be a block copolymer (e.g., a polyoxypropylene-polyoxyethylene block copolymer). Examples of the etherified products include polypropylene glycol alkyl ethers and alkyl ethers of oxypropylene-oxyalkylene copolymers (e.g., alkyl ethers of polyoxypropylene-polyoxyethylene copolymers). Examples of the esterified products include polypropylene glycol esters of carboxylic acids and carboxylic acid esters of oxypropylene-oxyalkylene copolymers (e.g., carboxylic acid esters of polyoxypropylene-polyoxyethylene copolymers).

[0076] Examples of polymer compounds containing at least a repeating structure of oxypropylene units include polypropylene glycol, polyoxypropylene-polyoxyethylene copolymers (such as polyoxypropylene-polyoxyethylene block copolymers), polypropylene glycol alkyl ethers (such as the above-mentioned R 2 alkyl ethers (methyl ether, ethyl ether, butyl ether, etc.) in which R is an alkyl having 10 or less carbon atoms (or 8 or less, or 6 or less), polyoxyethylene-polyoxypropylene alkyl ethers (the above R 2 alkyl ethers (butyl ether, hydroxyhexyl ether, etc.) in which R is an alkyl having 10 or less carbon atoms (or 8 or less, or 6 or less), polypropylene glycol carboxylate (the above R 3Examples of the polymer compound include polypropylene glycol carboxylates (such as polypropylene glycol acetate) in which the alkyl group has 10 or less carbon atoms (or 8 or less, or 6 or less), and polypropylene oxide adducts of triol or higher polyols (such as polypropylene oxide adducts of glycerin). However, the polymer compound is not limited to these.

[0077] The polymer compound is selected from the group consisting of oxy-C, ... 2-4 It is preferable that the polymer compound contains many alkylene units. Such a polymer compound contains, for example, an oxygen atom bonded to the terminal group and a -CH2- group and / or a -CH< group bonded to the oxygen atom. 1 In the H-NMR spectrum, the ratio of the integral of the peaks from 3.2 ppm to 3.8 ppm to the total integral of the peaks from 3.2 ppm to 3.8 ppm, the integral of the peaks of the hydrogen atoms of the -CH2- groups, and the integral of the peaks of the hydrogen atoms of the -CH< groups becomes large. This ratio is, for example, 50% or more, and may be 80% or more. From the viewpoint of further enhancing the effect of increasing the hydrogen overvoltage and easily ensuring higher charge acceptance, 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 its terminal and has a -CH2- group and / or a -CH< group bonded to the oxygen atom of the -OH group, 1 In the H-NMR spectrum, the peaks of the hydrogen atoms of the -CH2- group and the -CH< group have chemical shifts in the range of more than 3.8 ppm to 4.0 ppm.

[0078] The negative electrode material may contain one type of polymer compound or two or more types of polymer compounds.

[0079] The polymer compound may include, for example, a compound with an Mn of 5 million or less, a compound with an Mn of 1 million or less or 100,000 or less, or a compound with an Mn of 20,000 or less. From the viewpoint of ensuring higher discharge performance, the polymer compound preferably includes a compound with an Mn of 10,000 or less, a compound with an Mn of 5,000 or less or 3,000 or less, or a compound with an Mn of 2,500 or less or 2,000 or less. From the viewpoint of easily achieving the effect of increasing hydrogen overvoltage, the Mn of such a compound may be 300 or more, 400 or more, or even 500 or more. Two or more compounds with different Mn may be used as the polymer compound. In other words, the polymer compound may have multiple Mn peaks in the molecular weight distribution.

[0080] The Mn of the above compounds is 300 to 5 million (or 1 million or less), 400 to 5 million (or 1 million or less), 500 to 5 million (or 1 million or less), 300 to 100,000 (or 20,000 or less), 400 to 100,000 (or 20,000 or less), 500 to 100,000 (or 20,000 or less), 300 to 10,000 (or 50 00 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.

[0081] The content of the polymer compound in the negative electrode material is, for example, 5 ppm or more, and may be 10 ppm or more, by mass. From the viewpoint of increasing the hydrogen overvoltage and ensuring a longer life performance in a high-temperature cycle test, the content of the polymer compound in the negative electrode material is, by mass, preferably 20 ppm or more, more preferably 30 ppm or more, and may be 70 ppm or more or 100 ppm or more. The content of the polymer compound in the negative electrode material is, for example, 1000 ppm or less, and may be less than 1000 ppm, 800 ppm or less, 700 ppm or less, or 600 ppm or less, by mass. From the viewpoint of enhancing the effect of suppressing a decrease in charge acceptance and ensuring a longer life performance in a deep discharge cycle test, the content of the polymer compound in the negative electrode material is, by mass, preferably 550 ppm or less or 500 ppm or less.

[0082] The content of polymer compounds in the negative electrode material is, by mass, 5 ppm or more (or 10 ppm or more) and 1000 ppm or less, 5 ppm or more (or 10 ppm or more) and less than 1000 ppm, 5 ppm or more (or 10 ppm or more) and 800 ppm or less, 5 ppm or more (or 10 ppm or more) and 700 ppm or less, 5 ppm or more (or 10 ppm or more) and 600 ppm or less, 5 ppm or more (or 10 ppm or more) and 550 ppm or less, 5 ppm or more (or 10 ppm or more) and 500 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 less than 1000 ppm, 20 ppm or more (or 30 ppm or more) and 800 ppm or less ... The concentration may be 20 ppm or more (or 30 ppm or more) but not more than 700 ppm, 20 ppm or more (or 30 ppm or more) but not more than 600 ppm, 20 ppm or more (or 30 ppm or more) but not more than 550 ppm, 20 ppm or more (or 30 ppm or more) but not more than 500 ppm, 70 ppm or more (or 100 ppm or more) but not more than 1000 ppm, 70 ppm or more (or 100 ppm or more) but not more than 1000 ppm, 70 ppm or more (or 100 ppm or more) but not more than 800 ppm, 70 ppm or more (or 100 ppm or more) but not more than 700 ppm, 70 ppm or more (or 100 ppm or more) but not more than 600 ppm, 70 ppm or more (or 100 ppm or more) but not more than 550 ppm, or 70 ppm or more (or 100 ppm or more) but not more than 500 ppm.

[0083] (organic shrinkage preventer) An organic shrinkage preventer is an organic compound that functions to suppress shrinkage of lead, the negative electrode active material, when a lead-acid battery is repeatedly charged and discharged. Organic shrinkage preventers are generally broadly classified into lignin compounds and synthetic organic shrinkage preventers. Synthetic organic shrinkage preventers can also be said to be organic shrinkage preventers other than lignin compounds. Examples of organic shrinkage preventers contained in negative electrode materials include lignin compounds and synthetic organic shrinkage preventers. The negative electrode material may contain one type of organic shrinkage preventer, or two or more types of organic shrinkage preventers.

[0084] Examples of lignin compounds include lignin and lignin derivatives, etc. Examples of lignin derivatives include lignin sulfonic acid or salts thereof (such as alkali metal salts (such as sodium salts)).

[0085] Synthetic organic shrink-proofing agents are organic polymers containing sulfur, and generally contain multiple aromatic rings in the molecule and sulfur as sulfur-containing groups. Among the sulfur-containing groups, sulfonic acid groups or sulfonyl groups, which are stable, are preferred. The sulfonic acid groups may exist in either an acid form or a salt form such as a sodium salt.

[0086] At least a lignin compound may be used as the organic shrinkage inhibitor. When a lignin compound is used, charge acceptance tends to be lower than when a synthetic organic shrinkage inhibitor is used. However, when the negative electrode material contains a specific polymer compound, the decrease in charge acceptance is suppressed even when a lignin compound is used as the organic shrinkage inhibitor.

[0087] As the organic shrink-preventing agent, it is also preferable to use a condensation product containing at least an aromatic compound unit. Examples of such condensation products include condensation products of aromatic compounds with aldehyde compounds (at least one selected from the group consisting of aldehydes (e.g., formaldehyde) and condensates thereof). The organic shrink-preventing agent may contain one type of aromatic compound unit, or may contain two or more types of aromatic compound units. The aromatic compound unit refers to a unit derived from an aromatic compound incorporated into the condensation product.

[0088] Examples of aromatic rings possessed by aromatic compounds include benzene rings and naphthalene rings. When an aromatic compound has multiple aromatic rings, the multiple aromatic rings may be linked by a direct bond or a linking group (e.g., an alkylene group (including an alkylidene group), a sulfone group), or the like. Examples of such structures include bisarene structures (biphenyl, bisphenylalkane, bisphenylsulfone, etc.). Examples of aromatic compounds include compounds having the above-mentioned aromatic rings and at least one selected from the group consisting of a hydroxy group and an amino group. The hydroxy group or amino group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having a hydroxy group or an amino group. The hydroxy group also includes salts of the hydroxy group (-OMe). The amino group also includes salts of the amino group (specifically, salts with an anion). Examples of Me include alkali metals (e.g., Li, K, Na), and metals of Group 2 of the periodic table (e.g., Ca, Mg).

[0089] Preferred aromatic compounds include bisarene compounds (bisphenol compounds, hydroxybiphenyl compounds, bisarene compounds having an amino group (such as bisarylalkane compounds having an amino group, bisarylsulfone compounds having an amino group, and biphenyl compounds having an amino group), hydroxyarene compounds (such as hydroxynaphthalene compounds and phenol compounds), and aminoarene compounds (such as aminonaphthalene compounds and aniline compounds (such as aminobenzenesulfonic acid and alkylaminobenzenesulfonic acid)). The aromatic compounds may further have a substituent. The organic shrink-proofing agent may contain one or more of the residues of these compounds. Preferred bisphenol compounds include bisphenol A, bisphenol S, and bisphenol F.

[0090] The condensate preferably contains at least a unit of an aromatic compound having a sulfur-containing group. In particular, the use of a condensate containing at least a unit of a bisphenol compound having a sulfur-containing group is advantageous in ensuring higher charge acceptance.

[0091] The sulfur-containing group may be directly bonded to an aromatic ring contained in the compound, or may be bonded to the aromatic ring as an alkyl chain having the sulfur-containing group. The sulfur-containing group is not particularly limited, and examples thereof include a sulfonyl group, a sulfonic acid group, and salts thereof.

[0092] Furthermore, as the organic shrink-preventing agent, for example, at least one condensate containing at least one selected from the group consisting of the above-mentioned bisarene compound unit and a monocyclic aromatic compound unit (such as a hydroxyarene compound and / or an aminoarene compound) may be used. The organic shrink-preventing agent may also contain at least a condensate containing a bisarene compound unit and a monocyclic aromatic compound unit (especially a hydroxyarene compound). Examples of such condensates include condensates of a bisarene compound and a monocyclic aromatic compound with an aldehyde compound. Preferred hydroxyarene compounds are phenolsulfonic acid compounds (such as phenolsulfonic acid or its substitution products). Preferred aminoarene compounds are aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc. Preferred monocyclic aromatic compounds are hydroxyarene compounds.

[0093] The content of the organic shrinkage inhibitor in the negative electrode material is, for example, 0.005% by mass or more, and may be 0.01% by mass or more. When the content of the organic shrinkage inhibitor is in this range, high discharge performance can be ensured. The content of the organic shrinkage inhibitor may be, for example, 1.0% by mass or less, 0.5% by mass or less, or 0.2% by mass or less.

[0094] The content of the organic shrinkage preventer 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 0.005% by mass or more (or 0.01% by mass or more) and 0.2% by mass or less.

[0095] (carbonaceous material) Examples of the carbonaceous material contained in the negative electrode material include carbon black, graphite, hard carbon, and soft carbon. Examples of carbon black include acetylene black, furnace black, and lamp black. Furnace black also includes Ketjen Black (trade name). The graphite may be any carbonaceous material containing a graphite-type crystalline structure, and may be either artificial graphite or natural graphite. The negative electrode material may contain one type of carbonaceous material, or two or more types.

[0096] The content of the carbonaceous material in the negative electrode material is, for example, 0.05% by mass or more, or may be 0.10% by mass or more, and the content of the carbonaceous material is, for example, 5% by mass or less, or may be 3% by mass or less.

[0097] The content of the carbonaceous material in the negative electrode material may be 0.05% by mass to 5% by mass, 0.05% by mass to 3% by mass, 0.10% by mass to 5% by mass, or 0.10% by mass to 3% by mass.

[0098] (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, and 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.

[0099] The content of barium sulfate in the negative electrode material may be 0.05% by mass to 3% by mass, 0.05% by mass to 2% by mass, 0.10% by mass to 3% by mass, or 0.10% by mass to 2% by mass.

[0100] (Analysis of the components of negative electrode materials) The following describes the method for analyzing the components of the negative electrode material. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain the 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 washing is continued until a pH test paper is pressed against the washed surface of the negative electrode plate and no color change is confirmed. However, the washing time should be within two hours. The washed negative electrode plate is dried in a reduced pressure environment at 60±5°C for approximately six hours. If an adhesive material is present on the negative electrode plate after drying, the adhesive material is removed by peeling. Next, the negative electrode material is separated from the negative electrode plate to obtain a sample (hereinafter referred to as Sample A). Sample A is crushed as necessary and subjected to analysis.

[0101] (1) Analysis of polymer compounds (1-1) Qualitative analysis of polymer compounds (a) Oxy C 2-4 Alkylene unit analysis Pulverized sample A is used. 150.0±0.1 mL of chloroform is added to 100.0±0.1 g of sample A and stirred at 20±5°C for 16 hours to extract the polymer compound. The solids are then removed by filtration. The polymer compound obtained by extraction is dissolved in a chloroform solution, or the polymer compound obtained by drying the chloroform solution is identified by obtaining information from at least one of infrared spectroscopy, ultraviolet-visible absorption spectroscopy, NMR spectroscopy, LC-MS, and pyrolysis GC-MS.

[0102] The chloroform-soluble matter is recovered by distilling off the chloroform under reduced pressure from the chloroform solution in which the polymer compound obtained by extraction is dissolved. The chloroform-soluble matter is dissolved in deuterated chloroform and subjected to the following conditions: 1 1H-NMR spectrum is measured. 1 From the H-NMR spectrum, a peak with a chemical shift in the range of 3.2 ppm to 3.8 ppm is confirmed. Also, from the peak in this range, oxy C 2-4 Identify the type of alkylene unit.

[0103] Apparatus: AL400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. Observation frequency: 395.88MHz Pulse width: 6.30 μs Pulse repetition time: 74.1411 seconds Accumulation count: 32 Measurement temperature: room temperature (20~35℃) Standard: 7.24 ppm Sample tube diameter: 5 mm

[0104] 1 From the H-NMR spectrum, the integral value (V1) of the peaks present in the chemical shift range of 3.2 ppm to 3.8 ppm is determined. In addition, for each of the hydrogen atoms of the -CH2- group and -CH< group bonded to the oxygen atom bonded to the terminal group of the polymer compound, 1 The sum of the integral values ​​of the peaks in the H-NMR spectrum (V2) is calculated. Then, from V1 and V2, the percentage of V1 in the total of V1 and V2 (= V1 / (V1+V2) × 100(%)) is calculated.

[0105] In addition, in 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 on either side of the peak, and the line connecting these two points is used as the baseline to calculate each integral value. For example, for a peak with a chemical shift in the range of 3.2 ppm to 3.8 ppm, the line connecting the two points at 3.2 ppm and 3.8 ppm in the spectrum is used as the baseline. For example, for a peak with a chemical shift in the range of more than 3.8 ppm but not more than 4.0 ppm, the line connecting the two points at 3.8 ppm and 4.0 ppm in the spectrum is used as the baseline.

[0106] (b) Analysis of hydrophobic groups in esterified products When the polymer compound is an ester of a hydroxy compound, a predetermined amount of the polymer compound obtained by extracting and dissolving the chloroform solution containing the polymer compound in solution in (a) above is collected and an aqueous potassium hydroxide solution is added. This saponifies the ester, producing a fatty acid potassium salt and a hydroxy compound. The aqueous potassium solution is added until saponification is complete. A solution of methanol and boron trifluoride is added to the resulting mixture and mixed to convert the fatty acid potassium salt into a fatty acid methyl ester. The resulting mixture is analyzed by pyrolysis GC-MS under the following conditions to identify the hydrophobic groups contained in the ester. Analytical equipment: Shimadzu Corporation, high-performance general-purpose gas chromatogram GC-2014 Column: DEGS (diethylene glycol succinate) 2.1 m Oven temperature: 180~120℃ Inlet temperature: 240℃ Detector temperature: 240℃ Carrier gas: He (flow rate: 50 mL / min) Injection volume: 1μL~2μL

[0107] (c) Analysis of hydrophobic groups in etherified products When the polymer compound is an etherified product of a hydroxy compound, a predetermined amount of the polymer compound obtained by the extraction in (a) above is collected and hydrogen iodide is added to the polymer compound, which is obtained by drying the chloroform solution in which the polymer compound is dissolved. 3 ) corresponding to the iodide (R 3 I) is produced, and oxy C 2-4 Diiodo C corresponding to the alkylene unit 2-4 Alkanes are produced. The hydrogen iodide mentioned above is converted into etherified iodides and diiodo C. 2-4 A sufficient amount is added to complete the conversion to an alkane. The resulting mixture is analyzed by pyrolysis GC-MS under the same conditions as in (b) above to identify the hydrophobic groups contained in the etherified product.

[0108] (1-2) Quantitative analysis of polymer compounds The appropriate amount of the chloroform soluble matter was measured with an accuracy of ±0.0001 g. r (g) Dissolve in deuterated chloroform together with tetrachloroethane (TCE), 1 Measure the H-NMR spectrum. The integral value (S a ) and the integral value of the peak due to TCE (S r ) and calculate the mass-based content C of the polymer compound in the negative electrode material from the following formula: n Calculate the ppm.

[0109] C n =S a / S r ×N r / N a ×M a / M r ×m r / m×1000000 (In the formula, M a The molecular weight of the structure whose chemical shift shows a peak in the range of 3.2 to 3.8 ppm (more specifically, oxy C 2-4 (molecular weight of repeating alkylene units) and N a is the number of hydrogen atoms attached to the carbon atoms in the main chain of the repeating unit. r、 M r are the number of hydrogen atoms contained in the molecule of the reference material, the molecular weight of the reference material, and m (g) is the mass of the negative electrode material used for extraction.) In this analysis, the reference substance is TCE, so N r =2, M r = 168. Also, m = 100.

[0110] For example, if the polymer compound is polypropylene glycol, M a is 58, and N a is 3. If the polymer compound is polyethylene glycol, M a is 44, and N a is 4. In the case of copolymers, N aand M a are the N of each monomer unit, respectively. a Value and M a The value is an average value obtained by using the molar ratio (mol %) of each monomer unit contained in the repeating structure.

[0111] In quantitative analysis, 1 The integral value of the peak in the H-NMR spectrum is determined using data processing software "ALICE" manufactured by JEOL Ltd.

[0112] (1-3) Mn measurement of polymer compounds Using the above chloroform-soluble fraction, GPC measurement of the polymer compound is carried out using the following apparatus under the following conditions. Separately, a calibration curve (calibration curve) is created by plotting the Mn of the standard substance versus elution time. Based on this calibration curve and the GPC measurement results of the polymer compound, the Mn of the polymer compound is calculated. However, esterified or etherified products may be in a decomposed state in the chloroform-soluble fraction.

[0113] Analysis system: 20A system (Shimadzu Corporation) Column: Two GPC KF-805L (Shodex) columns connected in series Column temperature: 30°C ± 1°C Mobile phase: tetrahydrofuran Flow rate: 1mL / min. Concentration: 0.20% by mass Injection volume: 10μL Standard substance: polyethylene glycol (Mn = 2,000,000, 200,000, 20,000, 2,000, 200) Detector: Differential refractive index detector (Shodex RI-201H)

[0114] (2) Analysis of organic shrinkage inhibitors (2-1) Qualitative analysis of organic shrinkage inhibitors in negative electrode materials The crushed sample A is immersed in a 1 mol / L aqueous solution of sodium hydroxide to extract the organic shrink-preventing agent. Next, insoluble components are removed from the extract by filtration, and the resulting solution is desalted, concentrated, and dried. 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. A powder sample of the organic shrink-preventing agent (hereinafter referred to as sample B) is obtained by drying.

[0115] The type of organic shrink-proofing agent can be identified by combining information obtained from the infrared spectrum measured using sample B of the organic shrink-proofing agent obtained in this manner, the ultraviolet-visible absorption spectrum measured using an ultraviolet-visible absorption spectrometer after diluting sample B with distilled water or the like, the NMR spectrum of a solution obtained by dissolving sample B in a specified solvent such as heavy water, or information obtained from pyrolysis GC-MS or the like which can provide information on the individual compounds that make up the substance.

[0116] (2-2) Quantitative determination of the content of organic shrinkage inhibitor in negative electrode material As in (2-1) above, the separated material containing the organic shrinkage inhibitor is filtered to remove insoluble components, and a solution is obtained. The ultraviolet-visible absorption spectrum of each of the obtained solutions is measured. The content of each organic shrinkage inhibitor in the negative electrode material is determined using the intensity of the peak characteristic of each organic shrinkage inhibitor and a previously prepared calibration curve.

[0117] When obtaining a lead-acid battery with an unknown content of organic shrinkage inhibitor and measuring the content of the organic shrinkage inhibitor, it may be impossible to precisely identify the structural formula of the organic shrinkage inhibitor, and therefore it may not be possible to use the same organic shrinkage inhibitor for the calibration curve. In such cases, a calibration curve is created using a separately available organic polymer that shows similar shapes in the ultraviolet-visible absorption spectrum, infrared spectroscopy spectrum, NMR spectrum, etc. to the organic shrinkage inhibitor extracted from the negative electrode of the battery, and the content of the organic shrinkage inhibitor is measured using the ultraviolet-visible absorption spectrum.

[0118] (3) Quantitative analysis of carbonaceous materials and barium sulfate 50 ml of 20% by mass nitric acid was added to 10 g of crushed sample A, and the mixture was heated for approximately 20 minutes to dissolve the lead components as lead ions. The resulting solution was filtered to separate out the carbonaceous material, barium sulfate, and other solids.

[0119] The obtained solid content is dispersed in water to form a dispersion, and then components other than the carbonaceous material and barium sulfate (e.g., reinforcing material) are removed from the dispersion using a sieve. Next, the dispersion is subjected to suction filtration using a membrane filter whose mass has been measured in advance, and the membrane filter together with the filtered sample is dried in a dryer at 110°C ± 5°C. The filtered sample is a mixed sample of the carbonaceous material and barium sulfate. The mass of the membrane filter is subtracted from the total mass of the dried mixed sample (hereinafter referred to as Sample C) and the membrane filter to determine the mass of Sample C (M m ) is measured. Then, sample C is placed in a crucible together with the membrane filter and burnt at 1300°C or higher to be incinerated. The remaining residue is barium oxide. The mass of barium oxide is converted to the mass of barium sulfate to determine the mass of barium sulfate (M B ) to find the mass M m to mass M B The mass of the carbonaceous material is calculated by subtracting the above.

[0120] (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 chemically forming the unformed negative electrode plate. The negative electrode paste is produced, for example, by adding water and sulfuric acid (or an aqueous sulfuric acid solution) to lead powder, a polymer compound, and, if necessary, at least one selected from the group consisting of an organic shrinkage inhibitor, a carbonaceous material, and other additives, and kneading the mixture. When aging, it is preferable to age the unformed negative electrode plate at a temperature higher than room temperature and at high humidity.

[0121] The formation can be carried out by immersing an electrode plate assembly including unformed negative plates in an electrolyte containing sulfuric acid in a battery jar of a lead-acid battery and then charging the electrode plate assembly. However, the formation can also be carried out before assembling the lead-acid battery or the electrode plate assembly. The formation produces spongy lead.

[0122] (positive electrode plate) A paste-type positive electrode plate is used as the positive electrode plate of a lead-acid battery. The paste-type positive electrode plate includes a positive electrode current collector and a positive electrode material.

[0123] The positive electrode material contained in the positive electrode plate includes a positive electrode active material (lead dioxide or lead sulfate) that generates capacity through an oxidation-reduction reaction. The positive electrode material may also contain other additives as needed.

[0124] The positive electrode current collector may be formed by casting a lead alloy containing Sn, or by processing a lead alloy sheet containing Sn. Examples of processing methods include expanding and punching. A lattice-shaped current collector is preferably used as the positive electrode current collector because it is easy to support the positive electrode material.

[0125] The Sn content in the positive electrode current collector is preferably less than 3% by mass, more preferably 2.5% by mass or less, and may be 1.8% by mass or less or 1.6% by mass or less. When the Sn content is within this range, the positive electrode current collector tends to elongate due to corrosion, but even in this case, excellent life performance in high-temperature cycle tests can be ensured. This is also advantageous from the viewpoint of low cost. From the viewpoint of ensuring a higher life performance in high-temperature cycle tests, the Sn content in the positive electrode current collector is preferably 0.5% by mass or more, more preferably 0.7% by mass or more or 0.8% by mass or more.

[0126] The Sn content in the negative electrode current collector may be 0.5% by mass or more and less than 3% by mass (or 2.5% by mass or less), 0.7% by mass or more and less than 3% by mass (or 2.5% by mass or less), 0.8% by mass or more and less than 3% by mass (or 2.5% by mass or less), 0.5% by mass or more and 1.8% by mass or less (or 1.6% by mass or less), 0.7% by mass or more and 1.8% by mass or less (or 1.6% by mass or less), or 0.8% by mass or more and 1.8% by mass or less (or 1.6% by mass or less).

[0127] Examples of lead alloys that can be used to form the positive electrode current collector include Pb-Sn based alloys, Pb-Ca-Sn based alloys, etc. The lead alloy may further contain at least one additive element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, etc.

[0128] The positive electrode current collector may have a surface layer. The surface layer and the inner layer of the positive electrode current collector may have different compositions. The surface layer may be formed on a part of the positive electrode current collector. The surface layer may be formed only on the grid portion, only on the lug portion, or only on the frame portion of the positive electrode current collector.

[0129] Unformed paste-type positive electrode plates are obtained by filling a positive electrode current collector with positive electrode paste, aging it, and drying it. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid. The unformed positive electrode plate is then chemically formed to obtain a positive electrode plate.

[0130] The formation can be performed by immersing an electrode plate assembly including unformed positive plates in an electrolyte containing sulfuric acid in a battery container of a lead-acid battery and charging the electrode plate assembly, but the formation may also be performed before assembling the lead-acid battery or the electrode plate assembly.

[0131] (Quantitative analysis of Sn in positive electrode current collector) Prior to quantitative analysis of Sn, the positive electrode material was removed from the positive plate removed from the lead-acid battery to obtain a positive electrode current collector, and a portion of the positive electrode current collector was collected to prepare a sample for analysis. Specifically, the positive electrode material was vibrated to remove it from the positive electrode current collector, and then the remaining positive electrode material around the positive electrode current collector was removed using a ceramic knife. A portion of the positive electrode current collector with a metallic luster was collected as a sample. The mass of the collected sample was measured, and then it was mixed with tartaric acid and dilute nitric acid to obtain an aqueous solution. Hydrochloric acid was added to the aqueous solution to precipitate lead chloride, which was then filtered and the filtrate was collected. The Sn content in the positive electrode current collector was determined using the following procedure.

[0132] The Sn content of the positive electrode current collector is determined by lead separation inductively coupled plasma atomic emission spectroscopy as specified in JIS H2105:1955. More specifically, the Sn concentration in the filtrate is analyzed by a calibration curve method using an ICP atomic emission spectrometer, and the Sn content in the positive electrode current collector is determined from the Sn concentration and the mass of the collected sample. The ICP atomic emission spectrometer used is an ICPS-8000 manufactured by Shimadzu Corporation.

[0133] (Bag-shaped separator) The pouch-shaped separator is configured to accommodate the positive electrode plate. By overlapping the positive electrode plate accommodated in the pouch-shaped separator with the negative electrode plate, the separator is interposed between the positive electrode plate and the negative electrode plate. Although a nonwoven fabric may be used as the separator, it is preferable to use at least a microporous membrane.

[0134] A nonwoven fabric is a mat of intertwined fibers, not woven, and is primarily composed of fibers. For example, 60% or more by mass of a nonwoven fabric is made of fibers. Examples of fibers include glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers (polyethylene terephthalate fibers, etc.)), and pulp fibers. Nonwoven fabrics may contain components other than fibers, such as acid-resistant inorganic powders and polymers as binders.

[0135] A microporous membrane is a porous sheet (or film) mainly composed of a component other than a fiber component. The microporous membrane is preferably made of an acid-resistant material, and a microporous membrane mainly composed of a polymer component is preferred. The microporous membrane may contain a filler. From the viewpoints of low cost and excellent acid resistance, polyolefin (polyethylene, polypropylene, etc.) is preferred as the polymer component. Separators containing polyolefin are prone to oxidative degradation. However, because polymer compounds eluted from the negative electrode material adhere to the separator and act as antioxidants, oxidative degradation is suppressed even when a separator containing polyolefin is used, and long life performance in high-temperature cycle tests can be ensured.

[0136] The separator may be, for example, composed of only a microporous membrane, or may be a laminate of a nonwoven fabric and a microporous membrane, if necessary.

[0137] The pouch-shaped separator has at least ribs that protrude toward the positive electrode plate. Although such ribs tend to cause electrolyte with a high concentration of sulfate ions to settle in the space formed between the pouch-shaped separator and the positive electrode plate, by housing the positive electrode plate in the pouch-shaped separator, settling below the bottom of the separator is prevented, thereby reducing stratification.

[0138] More specifically, the pouch-shaped separator includes a base portion having a first surface on the positive electrode plate side and a second surface on the negative electrode plate side, and a rib (first rib) protruding from the first surface toward the positive electrode plate. The pouch-shaped separator typically includes a plurality of first ribs on the first surface.

[0139] The average thickness of the base portion is, for example, 0.1 mm or more, preferably 0.15 mm or more. When the average thickness of the base portion is in this range, the strength of the separator is increased, which is more advantageous from the viewpoint of reducing damage to the separator. From the viewpoint of easily ensuring a higher capacity, the average thickness of the base portion is, for example, 0.3 mm or less.

[0140] The average height of the first ribs is, for example, 0.3 mm or more, and preferably 0.4 mm or more. When the average height of the first ribs is within this range, an electrolyte with a high concentration of sulfate ions is likely to settle in the space formed between the separator and the positive electrode plate by the first ribs. However, even in this case, by accommodating the positive electrode plate in the separator, stratification can be effectively reduced, ensuring high life performance in high-temperature cycle tests. Furthermore, oxidation degradation of the separator can be suppressed. From the viewpoint of ensuring high capacity, the average height of the first ribs is, for example, 1.0 mm or less, and may be 0.7 mm or less. Note that, in the pouch-shaped separator, it is preferable that the first ribs are formed with such an average height at least in the region facing the positive electrode plate (preferably the region where the positive electrode material is present).

[0141] The average height of the first rib may be 0.3 mm or more (or 0.4 mm or more) and 1.0 mm or less, or 0.3 mm or more (or 0.4 mm or more) and 0.7 mm or less.

[0142] The pouch-shaped separator may have a rib (second rib) protruding from the second surface toward the negative electrode plate. However, if the second rib forms a space between the negative electrode plate and the separator, the electrolyte with a high concentration of sulfate ions will pass through the space and easily settle to the bottom of the battery container. Therefore, it is preferable that the average height of the second rib is lower than the average height of the first rib, and it is more preferable that the pouch-shaped separator does not have a second rib. The average height of the second rib is, for example, 0.3 mm or less, and may be 0.1 mm or less.

[0143] The average thickness of the base and the average height of the ribs are determined for a separator that is removed from a fully charged lead-acid battery, washed, and dried under subatmospheric pressure.

[0144] The average thickness of the base portion is determined by measuring the thickness of the base portion at five arbitrarily selected points in a cross-sectional photograph of the separator and averaging the measured values.

[0145] The average height of the first rib is determined by averaging the heights of the first rib measured at 10 arbitrarily selected locations on the first surface of the base. The height of the first rib refers to the distance from the first surface of the base at a predetermined position on the first rib to the top of the first rib. If the surface of the base is not flat, the height of the first rib is defined as the distance from the highest point on the first surface of the base to the top of the first rib at a predetermined position on the first rib when the separator is placed flat with the first rib side facing up.

[0146] The average height of the second rib is determined in the same manner as for the first rib. The height of the second rib is the distance from the second surface of the base portion at a predetermined position on the second rib to the top of the second rib, in the same manner as for the first rib.

[0147] The separator can be obtained, for example, by extruding a resin composition containing a pore-forming agent and a polymer component into a sheet, removing the pore-forming agent to form pores in the polymer component matrix, folding the sheet, and crimping the edges to form a bag. The ribs may be formed, for example, during extrusion molding, or by pressing the sheet with a roller having grooves corresponding to the ribs after molding or after removing the pore-forming agent. When a filler is used, it is added, for example, to the resin composition. Examples of the pore-forming agent include at least one selected from the group consisting of polymer powder and oil.

[0148] (electrolyte) The electrolyte is an aqueous solution containing sulfuric acid, which may be gelled as necessary. The electrolyte may contain the above-mentioned polymer compound.

[0149] The electrolytic solution may contain cations (e.g., metal cations) and / or anions (e.g., anions other than sulfate anions (e.g., phosphate ions)) as needed. Examples of metal cations include at least one selected from the group consisting of Na ions, Li ions, Mg ions, and Al ions.

[0150] 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 1.35 or less, and preferably 1.32 or less.

[0151] 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.

[0152] (others) A lead-acid battery can be obtained by a manufacturing method including a step of housing a plate assembly and an electrolyte in a cell chamber of a battery case. Each cell of the lead-acid battery includes a plate assembly and an electrolyte housed in each cell chamber. The plate assembly is assembled by stacking positive electrode plates, negative electrode plates, and a separator with the separator interposed between the positive electrode plates and the negative electrode plates prior to housing in the cell chamber. The positive electrode plates, negative electrode plates, electrolyte, and separator are each prepared prior to assembling the plate assembly. The manufacturing method of the lead-acid battery may include a step of chemically converting at least one of the positive electrode plates and the negative electrode plates, as necessary, after the step of housing the plate assembly and the electrolyte in the cell chamber.

[0153] The number of each electrode plate in the electrode plate assembly may be one or more. When the electrode plate assembly includes two or more negative electrode plates, as long as at least one negative electrode plate satisfies the condition (condition a) that the polymer compound is contained in the above-mentioned negative electrode plate, the effect of improving charge acceptance and the effect of increasing hydrogen overvoltage can be obtained according to the number of such negative electrode plates. From the viewpoint of further suppressing a decrease in charge acceptance and easily obtaining the effect of increasing hydrogen overvoltage, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of negative electrode plates included in the electrode plate assembly are negative electrode plates that satisfy condition a. Of the negative electrode plates included in the electrode plate assembly, the proportion of negative electrode plates that satisfy condition a is 100% or less. All of the negative electrode plates included in the electrode plate assembly may be negative electrode plates that satisfy condition a.

[0154] When the electrode plate assembly includes two or more positive electrode plates, from the viewpoint of reducing the elongation of the positive electrode current collector and ensuring a higher life performance in a high-temperature cycle test, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the positive electrode plates included in the electrode plate assembly are positive electrode plates that satisfy the condition (condition b) that the positive electrode current collector contains Sn and is housed in a pouch-shaped separator that has a first rib. Of the positive electrode plates included in the electrode plate assembly, the proportion of positive electrode plates that satisfy condition b is 100% or less. All of the positive electrode plates included in the electrode plate assembly may be positive electrode plates that satisfy condition b.

[0155] When a lead-acid battery has two or more cells, it is sufficient that the plate assemblies of at least some of the cells include negative plates that satisfy condition a and positive plates that satisfy condition b. From the viewpoint of further suppressing a decrease in charge acceptance and easily achieving the effect of increasing hydrogen overvoltage, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of cells included in the lead-acid battery include plate assemblies that include negative plates that satisfy condition a and positive plates that satisfy condition b. Of the cells included in the lead-acid battery, the proportion of cells that include plate assemblies that include negative plates that satisfy condition a and positive plates that satisfy condition b is 100% or less. It is preferable that all of the plate assemblies included in the lead-acid battery are plate assemblies that include negative plates that satisfy condition a and positive plates that satisfy condition b.

[0156] FIG. 1 shows an external view of an example of a lead-acid battery according to one embodiment of the present invention. The lead-acid battery 1 includes a battery case 12 that contains a plate group 11 and an electrolyte (not shown). The battery case 12 is divided into multiple cell chambers 14 by partition walls 13. Each cell chamber 14 contains one plate group 11. The opening of the battery case 12 is closed by a lid 15 that has a positive electrode terminal 16 and a negative electrode terminal 17. The lid 15 is provided with a vent plug 18 for each cell chamber. When rehydrating, the vent plug 18 is removed and rehydration liquid is added. The vent plug 18 may have the function of venting gas generated in the cell chambers 14 to the outside of the battery.

[0157] The electrode plate group 11 is formed by alternately stacking multiple negative electrode plates 3 and multiple positive electrode plates 2 with separators 4 interposed between them. The separators 4 are bag-shaped and individually package the positive electrode plates 2. In a cell chamber 14 located at one end of the battery case 12, a positive electrode shelf 6 that connects the ears 2a of multiple positive electrode plates 2 in parallel is connected to a feedthrough connector 8, and a negative electrode shelf 5 that connects the ears 3a of multiple negative electrode plates 3 in parallel is connected to a negative electrode pole 7. The negative electrode pole 7 is connected to a negative electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, a positive electrode pole 9 is connected to the positive electrode shelf 6, and a feedthrough connector 8 is connected to the negative electrode shelf 5. The positive electrode pole 9 is connected to a positive electrode terminal 16 outside the lid 15. Each of the through-connectors 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plate groups 11 of adjacent cell chambers 14 in series.

[0158] The positive electrode shelf 6 is formed by welding together the ears 2a provided on the top of each positive electrode plate 2 by a cast-on-strap method or a burning method. The negative electrode shelf 5 is also formed by welding together the ears 3a provided on the top of each negative electrode plate 3 in the same manner as the positive electrode shelf 6.

[0159] The lid 15 of the lead-acid battery has a single structure (single lid), but this is not limited to the illustrated example. The lid 15 may have a double structure, for example, including an inner lid and an outer lid (or top lid). A lid having a double structure may have a reflux structure between the inner lid and the outer lid for returning the electrolyte to the battery (inside the inner lid) from a reflux port provided in the inner lid.

[0160] (evaluation) In this specification, the life performance in each of the deep discharge cycle test and the high temperature cycle test is evaluated by the following procedure. The increase in hydrogen overvoltage in the negative electrode plate is evaluated based on the overcharge quantity of electricity. The overcharge quantity of electricity is measured by the following procedure.

[0161] (1) Life performance in deep discharge cycle tests A deep discharge cycle test is conducted at a depth of discharge of 50% (DOD50%), and life performance is evaluated based on the end-of-discharge voltage. For the evaluation, a lead-acid battery with a rated voltage of 2V / cell and seven positive and eight negative plates per cell is used. Specifically, a fully charged lead-acid battery is repeatedly discharged and charged at 40°C ± 2°C under the following conditions: The end-of-discharge voltage at 50% DOD discharge for each cycle is measured and monitored. The battery's life is determined when the voltage at 50% DOD discharge falls below 1.67V / cell. The battery's life performance is evaluated based on the number of cycles at which the battery reaches its end-of-life. Discharge: Discharge at a constant current of Y x In (A) for 2 hours (DOD 50%). Charging: Charge for 5 hours at a constant voltage of 2.6V / cell and a maximum current of Y×In (A). Here, In (A) is the current value (A) obtained by dividing the rated n-hour rate capacity (Ah) of a lead-acid battery by n. Y = n / 4. For example, if a lead-acid battery with a rated 20-hour rate capacity of 30 Ah is used, In = 30 / 20 = 1.5 (A), and Y = 20 / 4 = 5.

[0162] When measuring the specific gravity of the electrolyte after the deep discharge cycle test, the electrolyte is sampled from the upper part (within 10 mm below the electrolyte surface) and the lower part (within 10 mm above the lower end of the negative electrode plate) of the lead-acid battery container after the test, and the specific gravity is measured.

[0163] (2) Life performance in high-temperature cycle tests The high-temperature cycle test is conducted in accordance with SAE J2801 (high-temperature stability test). More specifically, the test is conducted under the conditions shown in Table 1. During this test, the end-of-discharge voltage, end-of-charge current, and open-circuit voltage (OCV) in step 20 are measured and monitored for each charge / discharge cycle. The end-of-life is determined to be the point at which at least one of the following conditions (a) to (c) is met. Life performance is evaluated based on the number of cycles at which the end-of-life is reached. A lead-acid battery with a rated voltage of 12 V, equipped with seven positive plates and eight negative plates per cell, is used for the test. (a) The voltage at the end of each discharge is 7.2V or less. (b) The current at the end of each charge exceeds 15A. (c) The OCV in step 20 is less than 12.0V.

[0164] [Table 1]

[0165] (3) Overcharged electricity amount To measure the overcharge quantity of electricity, a lead-acid battery with a rated voltage of 2V / cell and seven positive and eight negative plates per cell is used. To achieve a more accurate overcharge condition than the standard 4-10 minute test specified in JIS D5301:2019, a 1 minute discharge followed by a 10 minute charge (1-10 minute test) is conducted at 75°C ± 3°C (high-temperature light-load test). In the high-temperature light-load test, a fully charged lead-acid battery is discharged and charged under the following conditions, and this discharge and charge cycle is repeated for 1220 cycles. The overcharge quantity of electricity (charge quantity - discharge quantity) for each cycle up to 1220 cycles is summed to calculate the integrated value (Ah) of the overcharge quantity of electricity, and the overcharge quantity of electricity is evaluated based on this integrated value. A smaller charge quantity of electricity indicates a higher hydrogen overvoltage. Discharge: 25A, 1 minute Charging: 2.47V / cell, 25A, 10 minutes Tank temperature: 75°C ± 3°C

[0166] A lead-acid battery according to one aspect of the present invention will be summarized below.

[0167] (1) A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is measured using deuterated chloroform as a solvent. 1The polymer compound has a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of the H-NMR spectrum, the positive electrode current collector contains Sn, The lead-acid battery, wherein the pouch-shaped separator has a rib (first rib) that protrudes toward the positive electrode plate and houses the positive electrode plate.

[0168] (2) In the above (1), the polymer compound contains an oxygen atom bonded to a terminal group and a -CH2- group and / or a -CH< group bonded to the oxygen atom, The aforementioned 1 In the H-NMR spectrum, the ratio of the integral value of the peak to the total integral value of the peak, the integral value of the peak due to the hydrogen atom of the -CH- group, and the integral value of the peak due to the hydrogen atom of the -CH< group may be 85% or more.

[0169] (3) In the above (1) or (2), the polymer compound is oxy C 2-4 It may contain a repeating structure of alkylene units.

[0170] (4) A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is oxy C 2-4 The polymer compound includes a repeating structure of an alkylene unit, the positive electrode current collector contains Sn, the pouch-shaped separator has a rib protruding toward the positive electrode plate and houses the positive electrode plate.

[0171] (5) In any one of the above (1) to (4), the specific gravity of the electrolyte at 20° C. in a fully charged lead-acid battery may be 1.20 or more or 1.25 or more.

[0172] (6) In any one of the above (1) to (5), the specific gravity of the electrolyte at 20° C. in a fully charged lead-acid battery may be 1.35 or less or 1.32 or less.

[0173] (7) In any one of the above (1) to (6), the Sn content in the positive electrode current collector may be 0.5 mass % or more, 0.7 mass % or more, or 0.8 mass % or more.

[0174] (8) In any one of the above (1) to (7), the Sn content in the positive electrode current collector may be less than 3 mass %, 2.5 mass % or less, 1.8 mass % or less, or 1.6 mass % or less.

[0175] (9) In any one of the above (1) to (8), the polymer compound may include a compound having an 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.

[0176] (10) In any one of the above (1) to (9), the polymer compound may include a compound having an Mn of 300 or more, 400 or more, or 500 or more.

[0177] (11) In any one of the above (1) to (10), the polymer compound is oxy C 2-4 The compound contains at least one selected from the group consisting of a hydroxy compound having a repeating structure of an alkylene unit, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound, The hydroxy compound is polyC 2-4 Alkylene glycol, oxy C 2-4 Copolymers containing repeating alkylene units and polyol polyC 2-4It may be at least one selected from the group consisting of alkylene oxide adducts.

[0178] (12) In the above (11), the polymer compound contains the hydroxy compound, The hydroxy compound may contain a repeating structure of oxypropylene units.

[0179] (13) In the above (12), examples of the polymer compound include polypropylene glycol, polyoxypropylene-polyoxyethylene copolymers (such as polyoxypropylene-polyoxyethylene block copolymers), polypropylene glycol alkyl ethers (such as the above R 2 alkyl ethers (methyl ether, ethyl ether, butyl ether, etc.) in which R is an alkyl having 10 or less carbon atoms (or 8 or less, or 6 or less), polyoxyethylene-polyoxypropylene alkyl ethers (the above R 2 alkyl ethers (butyl ether, hydroxyhexyl ether, etc.) in which R is an alkyl having 10 or less carbon atoms (or 8 or less, or 6 or less), polypropylene glycol carboxylate (the above R 3 may contain at least one selected from the group consisting of polypropylene glycol carboxylates (such as polypropylene glycol acetate) in which the alkyl group has 10 or less carbon atoms (or 8 or less, or 6 or less), and polypropylene oxide adducts of triol or higher polyols (such as polypropylene oxide adducts of glycerin).

[0180] (14) In the above (11), the polymer compound has one or more hydrophobic groups, At least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

[0181] (15) In the above (14), the long-chain aliphatic hydrocarbon group may have 12 or more carbon atoms or 16 or more carbon atoms.

[0182] (16) In the above (14) or (15), the long-chain aliphatic hydrocarbon group may have 30 or less, 26 or less, or 22 or less carbon atoms.

[0183] (17) In any one of the above (11) and (14) to (16), the polymer compound contains at least one selected from the group consisting of the etherified product and the esterified product; Each of the etherified product and the esterified product may contain a repeating structure of oxyethylene units.

[0184] (18) In the above (17), the polymer compound may contain at least one selected from the group consisting of etherified polyethylene glycol (such as alkyl ethers), esterified polyethylene glycol (such as carboxylic acid esters), etherified polyethylene oxide adducts of the above polyols (such as alkyl ethers), and esterified polyethylene oxide adducts of polyols (such as triols or higher polyols) (such as carboxylic acid esters).

[0185] (19) In the above (17) or (18), the polymer compound may comprise at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene cocoate sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

[0186] (20) In any one of the above (17) to (19), the polymer compound may have an HLB of 4 or more, or 4.3 or more.

[0187] (21) In any one of the above (17) to (20), the polymer compound may have an HLB of 18 or less, 10 or less, 9 or less, or 8.5 or less.

[0188] (22) In any one of the above (1) to (21), the polymer content in the negative electrode material may be, by mass, 5 ppm or more, 10 ppm or more, 20 ppm or more, 30 ppm or more, 70 ppm or more, or 100 ppm or more.

[0189] (23) In any one of the above (1) to (22), the polymer content in the negative electrode material may be, by mass, 1000 ppm or less, less than 1000 ppm, 800 ppm or less, 700 ppm or less, 600 ppm or less, 550 ppm or less, or 500 ppm or less.

[0190] (24) In any one of the above (1) to (23), the negative electrode material may further contain an organic shrinkage preventer.

[0191] (25) In the above (24), the content of the organic shrinkage preventer in the negative electrode material may be 0.005% by mass or more, or 0.01% by mass or more.

[0192] (26) In the above (24) or (25), the content of the organic shrinkage preventer in the negative electrode material may be 1.0% by mass or less, 0.5% by mass or less, or 0.2% by mass or less.

[0193] (27) In any one of the above (1) to (26), the negative electrode material may further contain a carbonaceous material.

[0194] (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 0.10% by mass or more.

[0195] (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, or 3% by mass or less.

[0196] (30) In any one of the above (1) to (29), the negative electrode material may further contain barium sulfate.

[0197] (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.

[0198] (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.

[0199] (33) In any one of the above (1) to (32), the average height of the first rib may be, for example, 0.3 mm or more, or 0.4 mm or more.

[0200] (34) In any one of the above (1) to (33), the average height of the first rib may be 1.0 mm or less, or 0.7 mm or less.

[0201] (35) In any one of the above (1) to (34), the pouch-shaped separator may have a base portion having a first surface on the positive electrode plate side and a second surface on the negative electrode plate side, and the first rib may protrude from the first surface toward the positive electrode plate.

[0202] (36) In the above (35), the average thickness of the base portion may be 0.1 mm or more, or 0.15 mm or more.

[0203] (37) In the above (35) or (36), the average thickness of the base portion may be 0.3 mm or less.

[0204] (38) In any one of the above (35) to (37), the pouch-shaped separator may or may not have a rib (second rib) protruding from the second surface toward the negative electrode plate.

[0205] (39) In the above (38), the average height of the second rib may be 0.3 mm or less or 0.1 mm or less.

[0206] [Example] The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0207] Lead-acid batteries E1 to E16, R1 to R5, and C1 to C4 (1) Preparation of lead-acid batteries (a) Preparation of the negative electrode plate A negative electrode paste is obtained by mixing raw lead powder, a polymer compound shown in Tables 2 to 4, sodium lignosulfonate, a carbonaceous material (carbon black), and barium sulfate with an appropriate amount of aqueous sulfuric acid solution. The components are mixed so that the polymer compound content in the negative electrode material, determined by the previously described procedures, is the value shown in the tables, and the sodium lignosulfonate content is 0.1% by mass, the carbon black content is 0.2% by mass, and the barium sulfate content is 0.4% by mass. The Mn content of the PPG polymer compound, determined by the previously described procedures, is 2000. The negative electrode paste is filled into the mesh portion of a Pb-Ca-Sn alloy expanded grid, aged, and dried to obtain an unformed negative electrode plate.

[0208] In addition, when the polymer compound has a repeating structure of oxyethylene units, the polymer compound measured by the above-mentioned procedure 1 In the H-NMR spectrum, a peak derived from -CH2- of the oxyethylene unit is observed in the chemical shift range of 3.2 ppm to 3.8 ppm. When the polymer compound has a repeating structure of oxypropylene units, the peak of the polymer compound measured by the above-mentioned procedure 1 In the H-NMR spectrum, peaks derived from -CH2- of the oxypropylene unit are observed in the chemical shift range of 3.2 ppm to 3.42 ppm, and peaks derived from -CH< and -CH2- of the oxypropylene unit are observed in the chemical shift range of more than 3.42 ppm to 3.8 ppm. 1In the H-NMR spectrum, the ratio of the integral value of the peak from 3.2 ppm to 3.8 ppm to the total integral value of the peak from 3.2 ppm to 3.8 ppm, the integral value of the peak of the hydrogen atom of the -CH2- 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 96 to 100%.

[0209] (b) Preparation of the positive electrode plate The raw lead powder is mixed with a sulfuric acid solution to obtain a positive electrode paste. The positive electrode paste is filled into the mesh of a Pb or Pb alloy expanded grid that serves as a positive electrode current collector, and the resulting material is aged and dried to obtain an unformed positive electrode plate. A Pb-Ca-Sn alloy is used as the Pb alloy that constitutes the positive electrode current collector. In both cases, the Sn content in the Pb positive electrode current collector is 0% by mass, and the Sn content in the Pb-Ca-Sn alloy positive electrode current collector, both of which are determined using the procedure described above, is 0.8% by mass or 1.6% by mass.

[0210] (c) Preparation of test battery A lead-acid battery with a rated voltage of 2 V / cell and a rated 20-hour rate capacity of 30 Ah was fabricated as a test battery used to evaluate life performance and overcharge capacity in a deep discharge cycle test. A lead-acid battery with a rated voltage of 12 V and a rated 20-hour rate capacity of 59 Ah was fabricated as a test battery used to evaluate life performance in a high-temperature cycle test. Each lead-acid battery had a plate assembly consisting of seven positive plates and eight negative plates. One of the positive and negative plates was housed in a pouch-shaped separator and alternately stacked with the other plate to form a plate assembly. The pouch-shaped separator was made of a microporous polyethylene film with ribs protruding toward the positive plate. The base of the pouch-shaped separator had an average thickness of 0.25 mm, and the average height of the ribs was 0.55 mm. Each lead-acid battery contained the plates shown in Tables 2 to 4.

[0211] The electrode plate group is placed in a polypropylene container together with an electrolyte (aqueous sulfuric acid solution), and chemical formation is carried out inside the container to create a liquid lead-acid battery. After chemical formation, the lead-acid battery is almost fully charged. The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C is 1.28.

[0212] (2) Evaluation (a) Life performance in deep discharge cycle tests and specific gravity difference of electrolyte Using the test batteries, the life performance in the deep discharge cycle test is evaluated according to the procedure described above. The life performance in the deep discharge cycle test of each lead acid battery is evaluated as a ratio when the number of cycles at the end of the life of lead acid battery C1 is set to 100. A larger ratio indicates better life performance. In addition, the specific gravity of the electrolyte is measured in the upper and lower parts of the battery container after the deep discharge cycle test using the procedure described above, and the difference in specific gravity of the electrolyte is determined by subtracting the specific gravity of the upper part from the specific gravity of the lower part.

[0213] (b) Life performance in high-temperature cycle tests Using the test batteries, the life performance in the high temperature cycle test is evaluated according to the procedure described above. The number of cycles at the end of the life of the lead acid battery C1 is set to 100, and the life performance of each lead acid battery is calculated as a ratio. high temperature Evaluates life performance in cycle tests. A higher ratio indicates better life performance.

[0214] (c) Overcharged electricity amount Using the test batteries, the integrated value of the overcharged quantity of electricity is measured using the procedure described above. The integrated value (Ah) of the overcharged quantity of electricity of the lead-acid battery C1 is set to 100, and the overcharged quantity of electricity of each lead-acid battery is evaluated as a ratio.

[0215] The results are shown in Tables 2 to 4. Tables 2 to 4 also show the Sn content in the positive electrode current collector. Table 4 also shows the Mn and HLB of the polymer compounds. The Mn of polypropylene glycol (PPG) is the Mn determined by the procedure described above. The Mn of the etherified and esterified polyethylene glycols is the Mn of the esterified or etherified polyethylene glycol used in preparing the negative electrode material. Some of the data in Table 2 are excerpted and shown in Table 3. E1 to E16 are working examples. R1 to R5 are reference examples. C1 to C4 are comparative examples.

[0216] [Table 2]

[0217] [Table 3]

[0218] As shown in Table 3, when the positive electrode plate is housed in a pouch-shaped separator, the life performance in the deep discharge cycle test is improved compared to when the negative electrode plate is housed, but the life performance in the high-temperature cycle test is reduced (comparison between C1 and C2). When the positive electrode current collector contains Sn, the life performance in the high-temperature cycle test is also improved to some extent while maintaining high life performance in the deep discharge cycle test (comparison between C2 and C3 and C4). When the positive electrode plate is housed in a pouch-shaped separator, the life performance in the deep discharge cycle test is improved to some extent by including a polymer compound in the negative electrode material, but the life performance in the high-temperature cycle test is reduced (comparison between C2 and R3). The results of the life performance in the deep discharge cycle test correspond to the specific gravity difference of the electrolyte, suggesting that a small specific gravity difference and suppressed stratification improve the life performance in the deep discharge cycle test.

[0219] In contrast, when a positive electrode plate containing a Sn-containing positive current collector in a pouch-shaped separator is combined with a negative electrode plate containing a polymer compound, the life performance in a high-temperature cycle test can be significantly improved while maintaining relatively high life performance in a deep discharge cycle test (E3E8). For example, in terms of life performance in a high-temperature cycle test, C2 and C3 indicate that the Sn in the positive electrode current collector contributes to a 41% improvement, while C2 and R3 indicate that the polymer compound in the negative electrode material contributes to a 14% improvement. Therefore, C2, C3, and R3 predict that the life performance in a high-temperature cycle test when a positive electrode plate containing a Sn-containing positive current collector in a pouch-shaped separator is combined with a negative electrode plate containing a polymer compound will be 65 + 41 + 14 = 120%. However, in E3, the life performance in the high-temperature cycle test was 155%, significantly higher than the expected 120%, demonstrating a synergistic effect. Compared to C1, E3 and E8 have a smaller overcharge quantity of electricity, suggesting an increase in hydrogen overvoltage at the negative plate. This increase in hydrogen overvoltage is due to the polymer compound contained in the negative electrode material, and is thought to contribute to the excellent life performance in high-temperature cycle tests.

[0220] As shown in Table 2, from the viewpoint of ensuring a higher life performance in a high-temperature cycle test, the content of the polymer compound in the negative electrode material is preferably 20 ppm or more or 30 ppm or more, and may be 70 ppm or more or 100 ppm or more. From the viewpoint of ensuring a higher life performance in a deep discharge cycle test, the content is preferably 550 ppm or less or 500 ppm or less.

[0221] When the Sn content in the positive electrode current collector is less than 3 mass%, the positive electrode current collector typically elongates significantly, resulting in a decrease in life performance in a high-temperature cycle test. However, even when the Sn content is within this range, excellent life performance in a high-temperature cycle test can be ensured (E1 to E11) as shown in Table 2. From the viewpoint of ensuring a higher life performance in a high-temperature cycle test, the Sn content in the positive electrode current collector is preferably 0.5 mass% or more, more preferably 0.7 mass% or more or 0.8 mass% or more.

[0222] [Table 4]

[0223] As shown in Table 4, oxyC 2-4 Even when an ether or ester of a hydroxy compound having a repeating alkylene unit structure is used, high life performance can be ensured in both a deep discharge cycle test and a high-temperature cycle test. From the viewpoint of excellent balance of life performance in both a deep discharge cycle test and a high-temperature cycle test, an HLB of 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 is preferred. [Industrial Applicability]

[0224] The lead-acid batteries according to the first and second aspects of the present invention can be suitably used, for example, as starting power sources for vehicles (automobiles, motorcycles, etc.), power sources for industrial power storage devices for electric vehicles (forklifts, etc.), etc. Note that these uses are merely examples and the present invention is not limited to these uses. [Explanation of symbols]

[0225] 1:Lead acid battery 2: Positive electrode plate 2a: Positive electrode plate lug 3: Negative electrode plate 3a: Negative electrode plate lug 4: Bag-shaped separator 5: Negative electrode shelf 6: Positive electrode shelf 7: Negative pole 8: Through-connector 9: Positive pole 11: Plate group 12:Battery container 13: Bulkhead 14: Cell Room 15: Lid 16: Positive terminal 17: Negative terminal 18: Liquid vent plug

Claims

1. A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is measured using deuterated chloroform as a solvent. １ The polymer compound has a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of the H-NMR spectrum, The polymer content in the negative electrode material is 550 ppm or less by mass, the positive electrode current collector contains Sn, the pouch-shaped separator has a rib protruding toward the positive electrode plate and houses the positive electrode plate.

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

3. The polymer compound is oxy C ２－４ The lead acid battery according to claim 1 or 2, comprising a repeating structure of alkylene units.

4. A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a negative electrode plate, a positive electrode plate, and a pouch-shaped separator interposed between the negative electrode plate and the positive electrode plate, the negative electrode plate includes a negative electrode current collector and a negative electrode material; the positive electrode plate includes a positive electrode current collector and a positive electrode material; The negative electrode material is oxyC ２－４ The polymer compound includes a repeating structure of an alkylene unit, The polymer content in the negative electrode material is 550 ppm or less by mass, the positive electrode current collector contains Sn, the pouch-shaped separator has a rib protruding toward the positive electrode plate and houses the positive electrode plate.

5. The lead acid battery according to any one of claims 1 to 4, wherein the polymer content in the negative electrode material is 5 ppm or more by mass.

6. The lead acid battery according to any one of claims 1 to 5, wherein the content of Sn in the positive electrode current collector is 0.5 mass% or more.

7. The lead acid battery according to any one of claims 1 to 6, wherein the content of Sn in the positive electrode current collector is less than 3 mass%.

8. The polymer compound is oxy C ２－４ The compound contains at least one selected from the group consisting of a hydroxy compound having a repeating structure of an alkylene unit, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound, The hydroxy compound is polyC ２－４ Alkylene glycol, oxy C ２－４ A copolymer containing a repeating alkylene unit, and a polyol, polyC ２－４ The lead acid battery according to any one of claims 1 to 7, wherein the lead acid battery is at least one selected from the group consisting of alkylene oxide adducts.

9. the polymer compound contains the hydroxy compound, The lead-acid battery according to claim 8 , wherein the hydroxy compound contains a repeating structure of oxypropylene units.

10. The polymer compound has one or more hydrophobic groups, 9. The lead-acid battery according to claim 8, wherein at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

11. the polymer compound includes at least one selected from the group consisting of the etherified product and the esterified product, The lead-acid battery according to claim 8 or 10, wherein each of the etherified product and the esterified product contains a repeating structure of oxyethylene units.

12. The lead-acid battery according to claim 11, wherein the HLB of the polymer compound is 4 or more and 9 or less.

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