lead-acid batteries

Abstract

This lead-acid storage battery is provided with a negative electrode plate, a positive electrode plate, and an electrolyte solution. The negative electrode plate comprises a negative electrode material. The positive electrode plate includes a positive electrode collector and a positive electrode material. The negative electrode material includes a polymer compound having a peak in the range of 3.2 ppm to 3.8 ppm in a chemical shift in a 1H–NMR spectrum measured using a deuterated chloroform solvent. The positive electrode collector has a vertical frame skeleton, and the width of the vertical frame skeleton is 0.5 mm to 2 mm.

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. A lead-acid battery includes a negative electrode plate, a positive electrode plate, a separator (or mat), and an electrolyte. Each electrode plate includes a current collector and an electrode material. To impart various functions to the battery, additives are sometimes added to the components of the lead-acid battery.

[0003] Patent Document 1 proposes a lead-acid battery in which a copolymer of propylene oxide and ethylene oxide is added to the negative electrode plate active material in combination with lignin sulfonic acid.

[0004] Patent Document 2 discloses a lead-acid battery including a positive electrode having a first surface and a second surface opposite to the first surface, and a negative electrode having a first surface and a second surface opposite to the first surface, each of the positive electrode and the negative electrode being immersed in an electrolyte solution, and a fiber attachment mat at least partially covering at least one of the first and second surfaces of at least one of the positive electrode and the negative electrode, the fiber attachment mat including a plurality of fibers coated with a size composition, a binder composition, and one or more additives, the additives being selected from the group consisting of rubber additives, rubber derivatives, aldehydes, aldehyde derivatives, metal salts, fatty alcohol ethyl esters, and the like. The document proposes a lead-acid battery containing one or more additives selected from the group consisting of oxylates (alkoxylated alcohols with terminal OH groups), ethylene-propylene oxide block copolymers, sulfate esters (alkyl sulfates and alkyl ether sulfates), sulfonate esters (alkyl and olefin sulfonates), phosphate esters, sulfosuccinates, polyacrylic acid, polyaspartic acid, perfluoroalkyl sulfonic acid, polyvinyl alcohol, lignin, lignin derivatives, phenol-formaldehyde resins, cellulose, and wood flour, which additives reduce water loss in the lead-acid battery.

[0005] A frame for ensuring strength can be provided on the outer periphery of the electrode plate, surrounding the central portion filled with the electrode material. Patent Document 3 discloses an example in which lead powder, an organic shrinkage inhibitor consisting of a bisphenol condensate, carbon black, barium sulfate, and a synthetic fiber reinforcing agent are mixed with water and sulfuric acid so that the contents of the organic shrinkage inhibitor, carbon black, barium sulfate, and synthetic fiber reinforcing agent in the negative electrode material after chemical formation are 0.2 mass%, 0.2 mass%, 1.0 mass%, and 0.05 mass%, respectively, and the resulting negative electrode active material paste is filled into a punched grid having frames on all four sides, and then dried and aged to produce an unchemically formed negative electrode plate. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Publication No. 182662 / 1983 [Patent Document 2] Special Publication No. 2017-525092 [Patent Document 3] International Publication No. 2016 / 194328 Summary of the Invention [Problem to be solved by the invention]

[0007] When a lead-acid battery uses a positive electrode current collector with a vertical frame, the positive electrode plate may bend when used in a high-temperature overcharged state, which can lead to the active material falling off due to the bending of the plate, and thus the battery's lifespan may be shortened. Narrowing the width of the vertical frame can prevent the plate from bending and the active material from falling off. However, narrowing the width of the vertical frame can easily stretch the mesh (grid) of the current collector, which can lead to a short circuit due to the grid stretching, shortening the battery's lifespan. As a result, it is difficult to achieve a long-life lead-acid battery. [Means for solving the problem]

[0008] A lead-acid battery according to one aspect of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate includes 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 lead-acid battery includes a polymer compound having a peak in the range of 3.2 ppm to 3.8 ppm in a chemical shift of an H-NMR spectrum, the positive electrode current collector has a vertical frame, and the width of the vertical frame is 0.5 mm to 2 mm.

[0009] A lead-acid battery according to another aspect of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolyte, wherein the negative electrode plate includes a negative electrode material, and the positive electrode plate includes a positive electrode current collector and a positive electrode material, and the negative electrode material includes oxy-C. 2-4 The lead-acid battery includes a polymer compound containing a repeating structure of alkylene units, the positive electrode current collector has a vertical frame, and the width of the vertical frame is 0.5 mm or more and 2 mm or less. [Brief explanation of the drawings]

[0010] [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. [Figure 2] 1 is a graph plotting the degree of improvement in the number of cycles under high-temperature overcharge due to the addition of a polymer compound while varying the width of the vertical frame of a positive electrode current collector. DETAILED DESCRIPTION OF THE INVENTION

[0011] One aspect of the present invention is a lead-acid battery comprising a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate comprises 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 positive electrode current collector includes a polymer compound having 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 has a vertical frame, and the width of the vertical frame is 0.5 mm to 2 mm.

[0012] 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.

[0013] In lead-acid batteries equipped with vertical frame ribs, the wider the vertical frame ribs, the more likely the positive electrode plate will bend under high-temperature overcharge conditions. On the other hand, the thinner the vertical frame ribs, the more likely the ribs constituting the mesh (lattice) of the positive electrode current collector will stretch. Roughly speaking, if the width of the vertical frame ribs is 1 mm or more, the battery is likely to reach its end of life due to the active material falling off caused by the bending of the electrode plate. If the width of the vertical frame ribs is less than 1 mm, the battery is likely to reach its end of life due to a short circuit caused by the stretching of the ribs constituting the mesh of the positive electrode current collector (hereinafter referred to as "lattice stretching" regardless of whether the mesh forms a lattice).

[0014] However, adding a polymer compound to the negative electrode material can suppress overcharge current, thereby suppressing plate curvature and preventing active material loss, even when the vertical frame width is 1 mm or more. Furthermore, suppressing overcharge current also suppresses grid elongation when the vertical frame width is less than 1 mm. Specifically, when a polymer compound is added to the negative electrode material, if the vertical frame width is 2 mm or less, plate curvature and short circuits due to grid elongation are suppressed. Therefore, a long life can be achieved even when used in an environment where the battery is overcharged at high temperatures.

[0015] The frame frame is a part that forms the edge of the current collector and is arranged to surround the area where the electrode material of the electrode plate is filled. The vertical frame frame is a frame frame that extends approximately in the vertical direction of the lead-acid battery. The horizontal frame frame is a frame frame that extends approximately in the left-right direction, with the direction perpendicular to the vertical direction being the left-right direction. The vertical frame frame may extend in the vertical direction and also obliquely in the left-right direction. The width of the vertical frame frame refers to the maximum length of the vertical frame in a direction parallel to the main surface of the positive electrode plate on which the vertical frame is attached and perpendicular to the direction in which the vertical frame extends. The up-down direction of the lead-acid battery is defined below. The width of the vertical frame can be measured using a vernier caliper or the like by disassembling the lead-acid battery, removing the positive electrode plate, and removing the positive electrode material from the positive electrode plate. The positive electrode current collector from which the positive electrode material has been removed can be obtained by treating the positive electrode plate removed from the lead-acid battery with an alkaline mannitol solution and then rinsing with water.

[0016] Another aspect of the present invention is a lead-acid battery comprising a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate comprises a negative electrode material. The positive electrode plate comprises a positive electrode current collector and a positive electrode material. The negative electrode material is oxy-C. 2-4 The battery contains a polymer compound containing a repeating structure of alkylene units. The positive electrode current collector has a vertical frame, the width of which is 0.5 mm to 2 mm. Even in this configuration, adding the polymer compound to the negative electrode material can suppress overcharge current, plate curvature, and short circuits due to lattice elongation. Therefore, a long life can be achieved even in environments where the battery is used in high-temperature overcharged conditions.

[0017] In the lead-acid batteries according to one and other aspects of the present invention, the width of the vertical frame may be less than 2 mm, or may be 1.75 mm or less. The width of the vertical frame is preferably 1.5 mm or less or 1.25 mm or less. The width of the vertical frame may be 0.7 mm or more.

[0018] That is, the width of the vertical frame may be 0.5 mm or more and less than 2 mm (or 0.7 mm or more and less than 2 mm), or 0.5 mm or more and less than 1.75 mm (or 0.7 mm or more and less than 1.75 mm), with 0.5 mm or more and less than 1.5 mm (or 0.7 mm or more and less than 1.5 mm) being preferred. When the width of the vertical frame is in the range of 0.5 mm or more and less than 1.5 mm, the battery life under high-temperature overcharge is significantly improved. To achieve an even greater improvement in battery life under high-temperature overcharge, the width of the vertical frame may be 0.5 mm or more and less than 1.25 mm (or 0.7 mm or more and less than 1.25 mm).

[0019] In the lead-acid batteries according to one and other aspects of the present invention, the addition of a polymer compound suppresses overcharge current for the following reasons.

[0020] The polymer compound is oxy C 2-4 Since the repeating structure of alkylene units makes it easy to form a linear structure, the surface of lead in the negative electrode material can be thinly and widely coated with a polymer compound. Covering a wide area of the lead surface with the polymer compound increases the hydrogen overvoltage. This improves charge acceptance and makes it less likely for a side reaction that generates hydrogen during overcharging or charging to occur. This suppresses the overcharge current. Furthermore, since even a very small amount of polymer compound can reduce the hydrogen generation reaction, incorporating the polymer compound into the negative electrode material allows it to be present in the vicinity of lead, thereby reducing the amount of oxy-C. 2-4 The alkylene units can exhibit a high adsorption effect on lead.

[0021] The effects of the polymer compound as described above are exhibited 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 effects of the polymer compound to be exhibited effectively. Therefore, it is important that the negative electrode material contains a polymer compound, regardless of whether or not polymer compounds are contained in components of the lead-acid battery other than the negative electrode material.

[0022] The content of the polymer compound in the negative electrode material is preferably 750 ppm or less. In this case, the polymer compound film covering the lead surface does not become too thick, and high charge acceptance can be maintained. The content of the polymer compound in the negative electrode material is preferably 30 ppm or more and 500 ppm or less, and more preferably 250 ppm or more and 500 ppm or less, by mass. When the content of the polymer compound is within this range, the effect of improving the life when high-temperature overcharging is repeated is significant.

[0023] In the lead-acid batteries according to one and other aspects of the present invention, 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 of the peak between 3.2 ppm and 3.8 ppm to the total integral of this peak, the integral of the peak of the hydrogen atoms of the -CH2- groups bonded to the oxygen atoms, and the integral of the peak 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 facilitate a thin coating on the lead surface. This makes it easier to suppress overcharge current and achieves a long life even when high-temperature overcharge is repeated.

[0024] 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 is used, it is believed that the polymer compound is more easily adsorbed to lead and that the linear structure facilitates thin coating of the lead surface, thereby further suppressing overcharge current and achieving a longer life even when high-temperature overcharge is repeated.

[0025] 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 2-4 Copolymers containing repeating alkylene units and polyol polyC 2-4 The polymer compound may be at least one selected from the group consisting of alkylene oxide adducts. When such a polymer compound is used, the overcharge current is more easily suppressed, and the effect of improving the cycle life when high-temperature overcharge is repeated is significant.

[0026] The polymer compound may contain a repeating structure of an oxypropylene unit (-O-CH(-CH3)-CH2-). Such a polymer compound is thought to have an excellent balance of high adsorption to lead while being prevented from thickly adhering to the lead surface. Therefore, it is possible to effectively suppress overcharge current while maintaining high charge acceptance, and further improve the cycle life when high-temperature overcharge is repeated.

[0027] The polymer compound has one or more hydrophobic groups, and at least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The hydrophobic groups prevent excessive coating of the polymer compound on the lead surface, making it easier to simultaneously prevent a decrease in charge acceptance and reduce the amount of gas generation. The polymer compound preferably contains a repeating structure of oxyethylene units. By including a repeating structure of oxyethylene units with high hydrophilicity in the polymer compound, the polymer compound can be selectively adsorbed onto lead. The balance between the hydrophobic and hydrophilic groups can more effectively suppress overcharge current and further improve cycle life when high-temperature overcharge is repeated. As such a polymer compound, at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dilaurate, polyethylene glycol distearate, and polyethylene glycol dioleate can be preferably used.

[0028] 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).

[0029] 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.

[0030] (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.

[0031] (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.

[0032] In the above (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.

[0033] (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).

[0034] (organic shrinkage preventer) The organic shrinkage inhibitor refers to an organic compound among compounds that have the function of suppressing the shrinkage of lead, which is the negative electrode active material, when a lead-acid battery is repeatedly charged and discharged.

[0035] (number average molecular weight) The number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used to determine Mn is polyethylene glycol.

[0036] (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).

[0037] A fully charged lead-acid battery refers to a fully charged lead-acid battery that has already been formed. A lead-acid battery can be fully charged immediately after formation, or after some time has passed since formation (for example, a lead-acid battery that has been in use (preferably in the early stages of use) after 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.

[0038] (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.

[0039] 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.

[0040] [Lead acid battery] (negative plate) The negative electrode plate usually includes a negative electrode current collector in addition to a negative electrode material.

[0041] (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.

[0042] 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 the lug portion of the negative electrode current collector. The surface layer of the lug portion may contain Sn or an Sn alloy.

[0043] (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 an oxidation-reduction reaction. The negative electrode material may further include an organic shrinkage inhibitor. The negative electrode material may include at least one selected from the group consisting of carbonaceous materials 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.

[0044] (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.

[0045] 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.

[0046] Oxy C 2-4 Polymer compounds having a repeating structure of alkylene units also include those classified as surfactants (more specifically, nonionic surfactants).

[0047] 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.

[0048] As copolymers, different oxy C 2-4 Copolymers containing alkylene units may be used. The copolymer may be a block copolymer.

[0049] 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, etc.) 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, etc.). 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, sorbitol, etc. The sugar or sugar alcohol may have either a chain 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.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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.

[0054] 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.

[0055] 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.

[0056] Examples of alicyclic hydrocarbon groups include cycloalkyl groups (cyclopentyl, cyclohexyl, cyclooctyl, etc.), cycloalkenyl groups (cyclohexenyl, cyclooctenyl, etc.), etc. Alicyclic hydrocarbon groups also include hydrogenated products of the above aromatic hydrocarbon groups.

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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 enhance the effect of suppressing the decrease in charge acceptance. Furthermore, the use of these polymer compounds can also suppress overcharge current. Among these polymer compounds, polymer compounds having a repeating oxypropylene unit structure or a repeating oxyethylene unit structure are preferred.

[0062] 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), groups having 8 or more carbon atoms, preferably 12 or more, and 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 to lead and further enhance the effect of suppressing a decrease in charge acceptance. The polymer compound may have at least one hydrophobic group that is a long-chain aliphatic hydrocarbon group. The long-chain aliphatic hydrocarbon group may have 30 or less, 26 or less, or 22 or less carbon atoms.

[0063] 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.

[0064] Among polymer compounds, those 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 suppressing excessive coverage of the lead surface due to the balance between hydrophobicity and high hydrophilicity resulting from the repeating structure of oxyethylene units, thereby further enhancing the effect of suppressing a decrease in charge acceptance while reducing the amount of electricity during overcharge. Such polymer compounds can ensure high adsorption to lead even when they have a relatively low molecular weight (e.g., Mn of 1000 or less).

[0065] 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.

[0066] 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.

[0067] 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 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, but the polymer compounds are not limited to these. Among these, esterified polyethylene glycol and esterified polyethylene oxide adducts of the above polyols are preferred because they can ensure higher charge acceptance and significantly suppress overcharge current.

[0068] Among polymer compounds, those classified as surfactants preferably have an HLB of 4 or more, more preferably 4.3 or more, from the viewpoint of further reducing the amount of electrolyte loss. From the viewpoint of easily ensuring higher charge acceptance, 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.

[0069] 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 suppressing overcharge current and improving charge acceptance, 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.

[0070] Oxy C is recommended from the viewpoint of further enhancing the effect of suppressing overcharge current and making it easier to ensure higher charge acceptance. 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 in the case of a repeating oxyethylene unit, but even in this case, it is possible to ensure high charge acceptance while suppressing overcharge current. 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-.

[0071] 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).

[0072] 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), polyoxyethylene-polyoxypropylene alkyl ethers (such as alkyl ethers (butyl ethers) in which the above R2 is an alkyl having 10 or less carbon atoms (or 8 or less or 6 or less) carbon atoms), polypropylene glycol carboxylate (such as the above R2), 3 Examples of the polymer compound include, but are not limited to, 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).

[0073] In a polymer compound containing a repeating structure of oxypropylene units, the proportion of oxypropylene units is, for example, 5 mol% or more, or may be 10 mol% or more, or 20 mol% or more. The proportion of oxypropylene units is, for example, 100 mol% or less. In the copolymer, the proportion of oxypropylene units may be 90 mol% or less, or may be 75 mol% or less, or may be 60 mol% or less.

[0074] In a polymer compound containing a repeating structure of oxypropylene units, the proportion of oxypropylene units may be 5 mol% or more and 100 mol% or less (or 90 mol% or less), 10 mol% or more and 100 mol% or less (or 90 mol% or less), 20 mol% or more and 100 mol% or less (or 90 mol% or less), 5 mol% or more and 75 mol% or less (or 60 mol% or less), 10 mol% or more and 75 mol% or less (or 60 mol% or less), or 20 mol% or more and 75 mol% or less (or 60 mol% or less).

[0075] The polymer compound is preferably oxy-C, because it increases the adsorption of the polymer compound to lead and makes it easier for the polymer compound to take on a linear structure. 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 integral of the peak between 3.2 ppm and 3.8 ppm accounts for a large proportion of the total integral of this peak, the integral of the peak due to the hydrogen atom of the -CH2- group, and the integral of the peak due to the hydrogen atom of the -CH< group. This proportion is, for example, 50% or more, and may be 80% or more. From the viewpoints of further enhancing the effect of suppressing overcharge current and easily ensuring higher charge acceptance, the above proportion is preferably 85% or more, and more preferably 90% or more. For example, when a polymer compound has an -OH group at its terminal and also has a -CH2- group or a -CH< group bonded to the oxygen atom of the -OH group, 1In the H-NMR spectrum, the peaks of the hydrogen atoms of the -CH2- group and -CH< group have chemical shifts in the range of more than 3.8 ppm to 4.0 ppm.

[0076] The negative electrode material may contain one type of polymer compound or two or more types of polymer compounds.

[0077] The polymer compound may include, for example, a compound with an Mn of 5 million or less, a compound with an Mn of 3 million or less, or a compound with an Mn of 2 million or less, a compound with an Mn of 500,000 or less, or a compound with an Mn of 10,000 or less. From the viewpoint of ensuring higher charge acceptance, 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 a compound with an Mn of 4,000 or less, or a compound with an Mn of 3,000 or less, or a compound with an Mn of 2,500 or less. The Mn of such a compound may be 300 or more, 400 or more, or even 500 or more. From the viewpoint of further enhancing the effect of reducing the amount of electricity during overcharge, the Mn of such a compound is preferably 1,000 or more, more preferably 1,500 or more, or 1,800 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.

[0078] The content of the polymer compound in the negative electrode material is, for example, 8 ppm or more, and may be 10 ppm or more, by mass. From the viewpoint of suppressing overcharge current and improving cycle life in the event of repeated high-temperature overcharge, the content of the polymer compound in the negative electrode material is preferably 20 ppm or more, and more preferably 30 ppm or more, by mass. From the viewpoint of improving cycle life in the event of repeated high-temperature overcharge, the content of the polymer compound in the negative electrode material may be 750 ppm or less, 600 ppm or less, or even 500 ppm or less, by mass. From the viewpoint of ensuring high charge acceptance, the content of the polymer compound in the negative electrode material is preferably 600 ppm or less or 400 ppm or less, and more preferably 300 ppm or less, by mass.

[0079] The content (by mass) of the polymer compound in the negative electrode material may be 8 ppm or more (or 10 ppm or more) and 750 ppm or less, 8 ppm or more (or 10 ppm or more) and 600 ppm or less, 8 ppm or more (or 10 ppm or more) and 500 ppm or less, 8 ppm or more (or 10 ppm or more) and 400 ppm or less, 8 ppm or more (or 10 ppm or more) and 300 ppm or less, 20 ppm or more (or 30 ppm or more) and 750 ppm or less, 20 ppm or more (or 30 ppm or more) and 600 ppm or less, 20 ppm or more (or 30 ppm or more) and 500 ppm or less, 20 ppm or more (or 30 ppm or more) and 400 ppm or less, or 20 ppm or more (or 30 ppm or more) and 300 ppm or less.

[0080] (organic shrinkage preventer) Organic shrink-preventing agents are generally broadly classified into lignin compounds and synthetic organic shrink-preventing agents. Synthetic organic shrink-preventing agents can also be considered to be organic shrink-preventing agents other than lignin compounds. Examples of organic shrink-preventing agents contained in the negative electrode material include lignin compounds and synthetic organic shrink-preventing agents. The negative electrode material may contain one type of organic shrink-preventing agent or two or more types of organic shrink-preventing agents.

[0081] 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)).

[0082] 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.

[0083] 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, by including a specific polymer compound in the negative electrode material, even when a lignin compound is used as the organic shrinkage inhibitor, the decrease in charge acceptance is suppressed and high charge acceptance can be ensured.

[0084] 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.

[0085] Examples of aromatic rings contained in 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).

[0086] 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.

[0087] The condensate preferably contains at least a unit of an aromatic compound having a sulfur-containing group. In particular, using a condensate containing at least a unit of a bisphenol compound having a sulfur-containing group is advantageous in ensuring higher charge acceptance. From the viewpoint of enhancing the effect of reducing the amount of electricity during overcharge, it is also preferable to use a condensate of an aldehyde compound with a naphthalene compound having a sulfur-containing group and at least one selected from the group consisting of a hydroxyl group and an amino group.

[0088] 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 a 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.

[0089] 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.

[0090] 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, a high low-temperature high-rate discharge capacity can be ensured. The content of the organic shrinkage inhibitor is, for example, 1.0% by mass or less, and may be 0.5% by mass or less. From the viewpoint of further enhancing the effect of suppressing a decrease in charge acceptance, the content of the organic shrinkage inhibitor is preferably 0.3% by mass or less, more preferably 0.25% by mass or less, even more preferably 0.2% by mass or less or 0.15% by mass or less, and may be 0.12% by mass or less.

[0091] 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) to 1.0% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) to 0.5% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) to 0.3% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) to 0.25% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) to 0.2% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) to 0.15% by mass or less, or 0.005% by mass or more (or 0.01% by mass or more) to 0.12% by mass or less.

[0092] (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.

[0093] 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.

[0094] 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.

[0095] (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.

[0096] 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.

[0097] (Analysis of negative electrode materials or components) The following describes a method for analyzing negative electrode materials or their constituents. 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.

[0098] (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.

[0099] 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.

[0100] 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

[0101] 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.

[0102] In addition, in qualitative analysis, 1 When calculating the integral value of a peak in a H-NMR spectrum, 1In 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.

[0103] (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

[0104] (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.

[0105] (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.

[0106] 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 ais 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.

[0107] 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 a and 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.

[0108] 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.

[0109] (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.

[0110] 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)

[0111] (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 (hereafter referred to as sample B) is obtained by drying.

[0112] 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.

[0113] (2-2) Quantitative determination of the content of organic shrinkage inhibitor in negative electrode material As in (2-1) above, for each of the separated products containing the organic shrinkage inhibitor, insoluble components are removed by filtration to obtain a solution. 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.

[0114] When obtaining a lead-acid battery with an unknown content of organic shrinkage preventer and measuring the content of the organic shrinkage preventer, it may be impossible to precisely identify the structural formula of the organic shrinkage preventer, and therefore the same organic shrinkage preventer cannot be used for the calibration curve. In this case, 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 preventer extracted from the negative electrode of the battery, and the content of the organic shrinkage preventer is measured using the ultraviolet-visible absorption spectrum.

[0115] (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.

[0116] 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.

[0117] (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.

[0118] 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.

[0119] (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.

[0120] The positive 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 positive electrode current collector because it is easy to support the positive electrode material.

[0121] The lead alloy used for the positive electrode current collector is preferably a Pb-Sb alloy, a Pb-Ca alloy, or a Pb-Ca-Sn alloy in terms of corrosion resistance and mechanical strength. A frame is provided at the edge of the positive electrode current collector so as to surround the mesh portion (lattice portion) of the positive electrode current collector. A portion of the frame extends in the vertical direction and forms a vertical frame. 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 only a portion of the positive electrode current collector. The surface layer may be formed only on the lattice portion, only on the edge portion, or only on the frame portion of the positive electrode current collector.

[0122] 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.

[0123] An unformed paste-type positive electrode plate is obtained by filling a positive electrode current collector with a 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. Chemical formation can be performed by immersing an electrode plate assembly including unformed positive electrode plates in an electrolyte containing sulfuric acid in a lead-acid battery container and charging the electrode plate assembly. However, chemical formation may also be performed before assembling the lead-acid battery or the electrode plate assembly.

[0124] (separator) A separator can be disposed between the negative electrode plate and the positive electrode plate, and the separator is made of at least one material selected from a nonwoven fabric and a microporous membrane.

[0125] A nonwoven fabric is a mat of intertwined fibers without being woven, and is primarily composed of fibers. For example, 60% by mass or more of the nonwoven fabric is made of fibers. Examples of fibers that can be used include glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers (polyethylene terephthalate fibers, etc.)), and pulp fibers. Of these, glass fibers are preferred. The nonwoven fabric may contain components other than fibers, such as acid-resistant inorganic powders and polymers as binders.

[0126] On the other hand, a microporous membrane is a porous sheet mainly composed of components other than fiber components, and can be obtained, for example, by extruding a composition containing a pore-forming agent into a sheet, and then removing the pore-forming agent to form pores. The microporous membrane is preferably made of an acid-resistant material, and preferably is mainly composed of a polymer component. The polymer component is preferably polyolefin (polyethylene, polypropylene, etc.). The pore-forming agent can be at least one selected from the group consisting of polymer powder and oil.

[0127] The separator may be made of, for example, only a nonwoven fabric or only a microporous membrane. Furthermore, the separator may be a laminate of a nonwoven fabric and a microporous membrane, a laminate of different or the same materials, or a laminate of different or the same materials with recesses and protrusions interlocked, as needed.

[0128] The separator may be sheet-shaped or bag-shaped. A single sheet-shaped separator may be sandwiched between the positive electrode plate and the negative electrode plate. Alternatively, the electrode plates may be sandwiched between a single folded sheet-shaped separator. In this case, a positive electrode plate sandwiched between folded sheet-shaped separators may be stacked on top of a negative electrode plate sandwiched between folded sheet-shaped separators, or one of the positive electrode plate and the negative electrode plate may be sandwiched between folded sheet-shaped separators and stacked on top of the other electrode plate. Alternatively, a sheet-shaped separator may be folded into an accordion-like shape, and the positive electrode plate and the negative electrode plate may be sandwiched between the accordion-like separators so that the separator is interposed between them. When a separator folded like an accordion is used, the separator may be arranged so that the folded portion is aligned with the horizontal direction of the lead-acid battery (e.g., so that the folded portion is parallel to the horizontal direction) or so that the folded portion is aligned with the vertical direction (e.g., so that the folded portion is parallel to the vertical direction). In a separator folded like an accordion, recesses are formed alternately on both main surfaces of the separator. Because the positive and negative plates usually have lugs on the top, when the separator is arranged so that the folded portion is aligned with the horizontal direction of the lead-acid battery, the positive and negative plates are placed in the recesses on only one main surface of the separator (i.e., a double separator is interposed between adjacent positive and negative plates). When the separator is arranged so that the folded portion is aligned with the vertical direction of the lead-acid battery, the positive electrode plate can be accommodated in the recess on one main surface side, and the negative electrode plate can be accommodated in the recess on the other main surface side (that is, a single separator can be interposed between adjacent positive and negative electrode plates.) When a pouch-shaped separator is used, the pouch-shaped separator may accommodate either the positive electrode plate or the negative electrode plate.

[0129] (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.

[0130] 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.

[0131] 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.

[0132] 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.

[0133] (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.

[0134] The number of plates in the electrode plate assembly may be one or more. When the electrode plate assembly includes two or more positive electrode plates and two or more negative electrode plates, as long as the width of the vertical frame of the positive electrode current collector of at least one positive electrode plate is 0.5 mm or more and 2 mm or less, and the negative electrode material of at least one negative electrode plate contains the above-mentioned polymer compound, a cell including this electrode plate assembly can achieve a long life in an environment used in a high-temperature overcharged state, and the effect of achieving a long life increases depending on the number of such positive electrode plates and negative electrode plates. From the perspective of ensuring a long cycle life in an environment used in a high-temperature overcharged state, it is preferable that the width of the vertical frame of the positive electrode current collector be within the above range for 50% or more (more preferably, 80% or more or 90% or more) of the positive electrode plates included in the electrode plate assembly, and that the negative electrode material contain a polymer compound for 50% or more (more preferably, 80% or more or 90% or more) of the negative electrode plates included in the electrode plate assembly. The ratio of positive plates in the electrode plate group that satisfy the above condition is 100% or less. The ratio of negative plates in the electrode plate group that satisfy the above condition is 100% or less. All of the positive and negative plates in the electrode plate group may satisfy the above condition.

[0135] 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 positive and negative plates that satisfy the above conditions. From the viewpoint of achieving a longer life in an environment where the battery is used in a high-temperature overcharged state, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the cells included in the lead-acid battery include plate assemblies that include positive and negative plates that satisfy the above conditions. Of the cells included in the lead-acid battery, the proportion of cells that include plate assemblies that include positive and negative plates that satisfy the above conditions is 100% or less. It is preferable that all of the cells included in the lead-acid battery include positive and negative plates that satisfy the above conditions.

[0136] 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 negative electrode terminal 16 and a positive 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.

[0137] Each electrode plate group 11 is formed by stacking multiple negative electrode plates 2 and multiple positive electrode plates 3 with separators 4 interposed between them. Here, a pouch-shaped separator 4 is shown housing the negative electrode plates 2, but the shape of the separator is not particularly limited. In a cell chamber 14 located at one end of the battery case 12, a negative electrode shelf 6 that connects multiple negative electrode plates 2 in parallel is connected to a through-connector 8, and a positive electrode shelf 5 that connects multiple positive electrode plates 3 in parallel is connected to a positive electrode column 7. The positive electrode column 7 is connected to a positive electrode terminal 17 outside the lid 15. In a cell chamber 14 located at the other end of the battery case 12, a negative electrode column 9 is connected to the negative electrode shelf 6, and a through-connector 8 is connected to the positive electrode shelf 5. The negative electrode column 9 is connected to a negative electrode terminal 16 outside the lid 15. Each through-connector 8 passes through a through-hole provided in the partition wall 13 to connect the electrode plate groups 11 of adjacent cell chambers 14 in series.

[0138] The positive electrode shelf 5 is formed by welding the lugs provided on the top of each positive electrode plate 3 together using a cast-on-strap method or a burning method. The negative electrode shelf 6 is also formed by welding the lugs provided on the top of each negative electrode plate 2 together in the same manner as the positive electrode shelf 5.

[0139] 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.

[0140] In this specification, the cycle life when a high-temperature overcharge state is repeatedly performed is evaluated by the following procedure: The test battery used for the evaluation has a rated voltage of 2 V / cell and a rated 5-hour rate capacity of 32 Ah.

[0141] (a) High temperature overcharge test Cycle life is measured in accordance with the high-temperature overcharge test specified in SAE J2801:2007. The specified charge / discharge cycles are repeated in a water bath at 75°C ± 3°C in the sequence specified in the overcharge test. The test ends when the end-of-discharge voltage falls below 1.2V / cell or the end-of-charge current exceeds 15A. The number of specified charge / discharge cycles until the end of the test is considered to be the number of cycles in the high-temperature overcharge test.

[0142] (b) Amount of falling off After the above test, the test battery is disassembled and any electrode material that has fallen off to the bottom of the battery container is removed. The electrode material is washed with water, dried, and then the mass (g / cell) of the fallen electrode material is measured. If any electrode material is found to have fallen off, the positive and negative plates are visually inspected to determine whether the fallen electrode material is derived from the positive electrode material or the negative electrode material.

[0143] A lead-acid battery according to one aspect of the present invention will be summarized below.

[0144] (1) A lead-acid battery, The lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte, the negative electrode plate comprises 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 has a vertical frame, and the width of the vertical frame is 0.5 mm or more and 2 mm or less.

[0145] (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 50% or more, 80% or more, 85% or more, or 90% or more.

[0146] (3) In the above (1) or (2), the polymer compound is oxy C 2-4 It may contain a repeating structure of alkylene units.

[0147] (4) A lead-acid battery, The lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte, the negative electrode plate comprises 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 has a vertical frame, and the width of the vertical frame is 0.5 mm or more and 2 mm or less.

[0148] (5) In any one of (1) to (4) above, the width of the vertical frame bone may be 0.5 mm or more and less than 2 mm (or 0.7 mm or more and less than 2 mm), 0.5 mm or more and less than 1.75 mm (or 0.7 mm or more and less than 1.75 mm), 0.5 mm or more and less than 1.5 mm (or 0.7 mm or more and less than 1.5 mm), or 0.5 mm or more and less than 1.25 mm (or 0.7 mm or more and less than 1.25 mm).

[0149] (6) In any one of the above (1) to (5), the content of the polymer compound in the negative electrode material may be 750 ppm or less, 600 ppm or less, or 500 ppm or less by mass.

[0150] (7) In the above (6), the content of the polymer compound in the negative electrode material may be 30 ppm or more and 500 ppm or less by mass.

[0151] (8) In any one of the above (1) to (7), the polymer compound may include a compound having an Mn of 5 million or less, 3 million or less, 2 million or less, 500,000 or less, 100,000 or less, 50,000 or less, 20,000 or less, 10,000 or less, 5,000 or less, 4,000 or less, 3,000 or less, or 2,500 or less.

[0152] (9) In any one of the above (1) to (8), the polymer compound may include a compound having an Mn of 300 or more, 400 or more, 500 or more, 1000 or more, 1500 or more, or 1800 or more.

[0153] (10) In any one of the above (1) to (9), the polymer compound is the oxy C 2-4 The polymer 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 2-4 It may be at least one selected from the group consisting of alkylene oxide adducts.

[0154] (11) In the above (10), the polymer compound may contain at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dilaurate, polyethylene glycol distearate, and polyethylene glycol dioleate.

[0155] [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.

[0156] 《Lead acid batteries A1~A36》 (1) Preparation of lead-acid batteries (a) Preparation of the negative electrode plate A negative electrode paste is prepared by mixing lead powder, barium sulfate, carbon black, polyethylene glycol oleate (Mn500) as a polymer compound, and sodium lignin sulfonate as an organic shrinkage preventer with an appropriate amount of aqueous sulfuric acid solution. The components are mixed so that the polymer compound content in the negative electrode material (all determined by the procedures described above) is the value shown in Table 1, and the organic shrinkage preventer content is 0.1% by mass, barium sulfate content is 0.4% by mass, and carbon black content is 0.2% by mass. The negative electrode paste is filled into the mesh of a Pb-Ca-Sn alloy expanded grid, aged, and dried to obtain an unformed negative electrode plate.

[0157] (b) Preparation of the positive electrode plate The raw lead powder is mixed with an aqueous sulfuric acid solution to obtain a positive electrode paste. A punched current collector made of a Pb-Ca-Sn alloy is prepared. The punched current collector has a vertical frame width as shown in Table 1. The positive electrode paste is filled into the mesh portion of the positive electrode current collector, and the collector is aged and dried to obtain an unformed positive electrode plate.

[0158] (c) Preparation of test battery The test battery has a rated voltage of 2V / cell and a rated 5-hour rate capacity of 32Ah. The test battery's electrode plate assembly consists of seven positive and seven negative plates. The negative plates are housed in a pouch-shaped separator made of a microporous polyethylene film and are stacked alternately with the positive plates to form an electrode plate assembly. The electrode plate assembly is housed in a polypropylene battery case together with an electrolyte (aqueous sulfuric acid solution), and chemical formation is carried out inside the case to create a liquid lead-acid battery. The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C is 1.28.

[0159] In addition, when the polymer compound has a repeating structure of oxyethylene units, the polymer compound measured by the above-mentioned procedure 1In 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, a peak derived from --CH2- of the oxypropylene unit is 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. 1 In the H-NMR spectrum, the percentage of the integral of the peak between 3.2 ppm and 3.8 ppm to the total integral of this peak, the integral of the peaks of hydrogen atoms of -CH- groups bonded to oxygen atoms, and the integral of the peaks of hydrogen atoms of -CH< groups bonded to oxygen atoms is 96 to 100%.

[0160] In this way, batteries A1 to A36 were fabricated with different combinations of the polymer compound content in the negative electrode material and / or the width of the vertical frame of the positive electrode current collector, and were evaluated as described below. Note that batteries A2 to A8, A11 to A17, A20 to A26, and A29 to A35 are examples, and batteries A1, A9, A10, A18, A19, A27, A28, and A36 are comparative examples.

[0161] 《Lead acid batteries B1~B9》 In the preparation of the negative electrode plate, a negative electrode paste containing no polymer compound was prepared. The negative electrode plate was prepared in the same manner as in Batteries A1 to A24, and test batteries were prepared. In this manner, Batteries B1 to B9 (reference examples) were prepared, each of which contained no polymer compound in the negative electrode material and had different vertical frame widths for the positive electrode current collector, and were evaluated as described below.

[0162] 《Lead acid batteries C1~C3》 In the preparation of the negative electrode plate, the polymer compound was changed to the compound shown in Table 3 to obtain a negative electrode paste. The components of the negative electrode paste were mixed so that the content of the polymer compound in the negative electrode material obtained by the procedure described above was 0.025 mass% (250 ppm). Batteries C1 to C3 (Examples) were prepared in the same manner as Battery A13 except for the above, and evaluated as described below.

[0163] The polymer compounds used in batteries C1, C2, and C3 were polyethylene glycol dilaurate (Mn 630), polyethylene glycol distearate (Mn 820), and polyethylene glycol dioleate (Mn 500), respectively.

[0164] (2) Evaluation (a) High temperature overcharge test Using the above test batteries, the number of cycles under high-temperature overcharge conditions was measured using the procedure described above. After measuring the number of cycles, the batteries were disassembled and the amount of electrode material that had fallen off was measured. The life performance of each lead-acid battery under high-temperature overcharge was evaluated based on the ratio of the number of cycles for lead-acid battery B1 to 100. The amount of electrode material that had fallen off for each lead-acid battery was also evaluated based on the ratio of the number of cycles for lead-acid battery B1 to 100.

[0165] The results are shown in Tables 1 to 3. Tables 1 and 2 show the content of the polymer compound in the negative electrode material used in each lead-acid battery and the width of the vertical frame of the positive electrode current collector, along with the number of cycles under high-temperature overcharge conditions and the amount of electrode material lost. Table 3 shows the polymer compound used in each lead-acid battery and the width of the vertical frame of the positive electrode current collector, along with the number of cycles under high-temperature overcharge conditions and the amount of electrode material lost. In Table 2, when the width of the vertical frame of the positive electrode current collector is 0 mm, no frame is provided on the positive electrode current collector.

[0166] As shown in Table 2, when the negative electrode material does not contain a polymer compound, the amount of electrode material falling off is small when the width of the vertical frame is 1 mm or less, and the problem of reduced life performance due to electrode material falling off does not occur. Therefore, as the width of the vertical frame increases, short circuits due to lattice elongation are suppressed and the number of cycles increases (Batteries B1 to B4). However, when the width of the vertical frame exceeds 1 mm, the amount of electrode material falling off increases significantly, and the number of cycles decreases as the width of the vertical frame increases (Batteries B5 to B9).

[0167] In contrast, adding a polymer compound to the negative electrode material reduces the amount of electrode material that falls off, allowing a high number of cycles under high-temperature overcharge conditions to be maintained even when the vertical frame width is 1 mm or more. Batteries A1 to A36 allow a high number of cycles under high-temperature overcharge conditions to be maintained at least when the vertical frame width is in the range of 0.5 mm to 2 mm, i.e., in a wider range of vertical frame widths than when a polymer compound is not added to the negative electrode material, and this increases the degree of freedom in designing the current collector, including the vertical frame.

[0168] When the positive electrode current collector does not have a vertical frame (frame width is 0 mm), the increase in cycle count due to the addition of the polymer compound is small when comparing Batteries A1, A10, A19, A28, and B1. For example, the addition of the polymer compound to Batteries A1 and A28 barely improves the cycle count compared to Batteries B1. However, when the width of the vertical frame of the positive electrode current collector is 0.5 mm or more, the addition of the polymer compound to the negative electrode material significantly increases the cycle count.

[0169] Figure 2 is a graph plotting the difference in cycle count for batteries A10 to A18, each containing 0.025% by mass of polymer compound in the negative electrode material, compared to batteries (B1 to B9) with the same width of the vertical frame of the positive electrode current collector but without the addition of polymer compound, showing the degree of improvement in cycle count due to the addition of polymer compound. Figure 2 shows that a significantly higher improvement in cycle count is achieved when the width of the vertical frame is in the range of 0.5 mm to 2 mm.

[0170] [Table 1]

[0171] [Table 2]

[0172] [Table 3] [Industrial Applicability]

[0173] The lead-acid batteries according to one aspect and another aspect of the present invention are suitable for use in idle-stop vehicles, for example, as an IS lead-acid battery that is charged and discharged under PSOC conditions. Furthermore, the lead-acid batteries can be suitably used, for example, as starting power sources for vehicles (cars, motorcycles, etc.) and industrial power storage devices (for example, power sources for electric vehicles (forklifts, etc.)). Note that these uses are merely examples, and the present invention is not limited to these uses. [Explanation of symbols]

[0174] 1:Lead acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 5: Positive electrode shelf 6: Negative electrode shelf 7: Positive pole 8: Through-connector 9: Negative pole 11: Plate group 12:Battery container 13: Bulkhead 14: Cell Room 15: Lid 16: Negative terminal 17: Positive terminal 18: Liquid vent plug

Claims

1. A lead-acid battery, The lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte, the negative electrode plate comprises 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 has a vertical frame, and the width of the vertical frame is 0.5 mm or more and 2 mm or less.

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 a negative electrode plate, a positive electrode plate, and an electrolyte, the negative electrode plate comprises 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 positive electrode current collector has a vertical frame, and the width of the vertical frame is 0.5 mm or more and 2 mm or less.

5. The lead-acid battery according to any one of claims 1 to 4, wherein the width of the vertical frame is 0.5 mm or more and 1.5 mm or less.

6. The lead acid battery according to any one of claims 1 to 5, wherein the content of the polymer compound in the negative electrode material is 750 ppm or less by mass.

7. The lead-acid battery according to claim 6, wherein the content of the polymer compound in the negative electrode material is 30 ppm or more and 500 ppm or less by 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. 9. The lead-acid battery according to claim 8, wherein the polymer compound comprises at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dilaurate, polyethylene glycol distearate, and polyethylene glycol dioleate.

Images