lead-acid batteries

Abstract

A lead acid storage battery which is provided with an electrode plate group, an electrolyte solution, and a battery case that contains the electrode plate group and the electrolyte solution, wherein: the electrode plate group comprises a positive electrode plate, a negative electrode plate, and a separator that is interposed between the positive electrode plate and the negative electrode plate; the pull-out load at the time when the electrode plate group is pulled out from the battery case is not less than 1.5 times the weight of the electrode plate group itself; the surface roughness of the negative electrode plate is 0.4 mm or less; the negative electrode plate contains a negative electrode material; the negative electrode material contains a polymer compound; and the polymer compound has a peak within the range of from 3.2 ppm to 3.8 ppm in the chemical shift of the 1H-NMR spectrum as determined with use of heavy chloroform that serves as a solvent.

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 describes a method for producing an electrode for a lead-acid battery, which comprises the steps of filling a support with a kneaded active material, which is formed by adding and kneading a fluororesin dispersion to form fluororesin fibers, and then infiltrating the electrode with an aqueous silicone emulsion, followed by a drying step.

[0004] On the other hand, Patent Document 2 proposes a method for manufacturing a sealed lead-acid battery, which involves filling a grid with a paste mainly composed of lead oxide, dilute sulfuric acid, and water, and then pressing the electrode plate, in which the paste is in a plastic state before aging and drying, while spraying an aqueous solution of absorbent silica powder, to smooth the surface. Patent Document 2 also proposes that the average roughness of the electrode plate surface after pressing be 50 μm or less. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Unexamined Patent Publication No. 19863 / 1986 [Patent Document 2] Japanese Patent Application Publication No. 1-294360 Summary of the Invention [Problem to be solved by the invention]

[0006] Lead-acid batteries are sometimes used in a state of insufficient charge known as partial state of charge (PSOC). For example, lead-acid batteries installed in vehicles with idle stop (IS) systems are used in PSOC. When a lead-acid battery is used in PSOC, stratification occurs, where the electrolyte density gradually decreases in the upper part of the battery and increases in the lower part. As stratification progresses, lead sulfate accumulates significantly in the lower part of the negative plate, making sulfation, in which lead sulfate crystals form, more likely to occur. This reduces capacity and causes uneven charge-discharge reactions, deteriorating the plate and shortening the lifespan of the lead-acid battery.

[0007] One way to prevent stratification is to increase the load required to pull the plate assembly out of the battery case. However, increasing the pull-out load reduces the charge transfer resistance, promotes the hydrogen generation reaction, and increases the amount of overcharge electricity (amount of electrolyte loss).

[0008] In other words, there is a demand for a lead-acid battery that can achieve both an improved lifespan when used in PSOC and suppression of the amount of electricity that is overcharged (amount of loss of electrolyte). [Means for solving the problem]

[0009] One aspect of the present invention relates to a battery comprising: an electrode plate assembly; an electrolyte; and a battery case containing the electrode plate assembly and the electrolyte, wherein the electrode plate assembly comprises a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate; wherein a pull-out load when the electrode plate assembly is pulled out of the battery case is 1.5 times or more the weight of the electrode plate assembly; the negative electrode plate has a surface roughness of 0.4 mm or less; the negative electrode plate includes a negative electrode material; the negative electrode material includes a polymer compound; and the polymer compound is measured using deuterated chloroform as a solvent. 1 The present invention relates to a lead-acid battery having a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of the H-NMR spectrum.

[0010] Another aspect of the present invention is a battery comprising: an electrode plate group; an electrolyte; and a battery case containing the electrode plate group and the electrolyte, wherein the electrode plate group comprises positive electrode plates, negative electrode plates, and a separator interposed between the positive electrode plates and the negative electrode plates, wherein a pull-out load when the electrode plate group is pulled out of the battery case is 1.5 times or more the weight of the electrode plate group itself, the negative electrode plates have a surface roughness of 0.4 mm or less, the negative electrode plates contain a negative electrode material, and the negative electrode material contains a polymer compound, and the polymer compound is made of oxy-C 2-4 The present invention relates to a lead-acid battery having a repeating structure of alkylene units. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a partially cutaway exploded perspective view showing the external appearance and internal structure of a lead-acid battery according to one embodiment of the present invention. [Figure 2] FIG. 2 is a conceptual diagram of a negative electrode plate for explaining a method for measuring the surface roughness of the negative electrode plate. DETAILED DESCRIPTION OF THE INVENTION

[0012] A lead-acid battery according to one embodiment of the present invention includes a plate assembly, an electrolyte, and a battery case for containing the plate assembly and the electrolyte. The plate assembly includes positive and negative electrode plates, and a separator interposed between the positive and negative electrode plates.

[0013] A negative electrode plate includes a negative electrode material. A positive electrode plate includes a positive electrode material. The negative and positive electrode materials are usually held by a current collector. The electrode material is 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 electrode material excluding the current collector and attachment member.

[0014] The negative electrode material includes a polymer compound. The polymer compound 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. 2-4 It may have a repeating structure of alkylene units. 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.

[0015] By incorporating a polymer compound into the negative electrode material, it is expected that the amount of electricity during overcharging (amount of loss of electrolyte) will be reduced. This is due to the following reasons. First, the polymer compound tends to have a linear structure, and the lead surface in the negative electrode material is thinly and widely covered with the polymer compound. The polymer compound incorporated into the negative electrode material exists in the vicinity of the lead, so the oxy-C 2-4 It is believed that the alkylene units exhibit a high adsorption effect on lead. Covering a wide area of ​​the lead surface with the polymer compound increases the hydrogen overvoltage, making it less likely for hydrogen to be generated during overcharge and reducing loss of electrolyte. To effectively utilize the effects of the polymer compound, it is important that the negative electrode material contains a polymer compound, regardless of whether or not other components of the lead-acid battery contain the polymer compound.

[0016] On the other hand, some of the polymer compounds adsorbed to the lead surface dissolve into the electrolyte due to volume changes in the negative electrode material during charging and discharging and external forces associated with hydrogen gas generation. The polymer compounds dissolved into the electrolyte migrate to the positive electrode plate and are oxidatively decomposed. This reduces charge acceptance. When lead-acid batteries are used in PSOC (post-charge off-loading) mode, where the specific gravity of the electrolyte at the bottom of the battery is high, the dissolution of polymer compounds from the negative electrode material is accelerated, resulting in a corresponding decrease in charge acceptance and a shortened cycle life. Furthermore, the dissolution of polymer compounds from the negative electrode material reduces its effectiveness in suppressing overcharge charge (electrolyte loss). Even if the amount of polymer compound added to the negative electrode material is increased, the amount of polymer compound dissolved from the negative electrode material increases, making it difficult to fully restore the effect of suppressing overcharge charge (electrolyte loss).

[0017] In other words, when a lead-acid battery is used in PSOC, even if a polymer compound is contained in the negative electrode material, the effect of suppressing the amount of electricity in overcharge (amount of loss of electrolyte) may be reduced, which may actually result in a decrease in cycle life.

[0018] In contrast, by setting the pull-out load (hereinafter simply referred to as "pull-out load") when pulling the plate assembly out of the battery case to at least 1.5 times the weight of the plate assembly and setting the surface roughness of the negative plate to 0.4 mm or less, it is possible to suppress the overcharge electricity (amount of electrolyte loss) and significantly improve the cycle life of the lead-acid battery, even when used in PSOC. This is thought to be because when the pull-out load is set to at least 1.5 times the weight of the plate assembly and the surface roughness of the negative plate is set to 0.4 mm or less, stratification is significantly suppressed and the elution of polymer compounds from the negative electrode material is significantly suppressed.

[0019] On the other hand, even if a polymer compound is included in the negative electrode material, simply increasing the pull-out load to 1.5 times or more the weight of the plate assembly only slightly suppresses stratification, and it is difficult to suppress the elution of the polymer compound into the electrolyte. Because the surface of a negative electrode plate is typically quite uneven, increasing the pull-out load does not adequately suppress stratification of the electrolyte and the elution of the polymer compound. As a result, as stratification progresses, the elution and oxidative decomposition of the polymer compound are promoted, reducing charge acceptance and significantly shortening cycle life. Furthermore, the elution of the polymer compound from the negative electrode material reduces the effectiveness of reducing the amount of electricity in overcharge.

[0020] The surface irregularities of the negative electrode plate are formed during the manufacturing process. For example, when filling the negative electrode current collector with negative electrode paste, the negative electrode paste is pressed against the negative electrode current collector with a specific jig to facilitate filling. As a result, irregularities are formed on the surface of the negative electrode material, resulting in a negative electrode plate with a surface roughness exceeding 0.4 mm.

[0021] Similarly, even if the negative electrode material contains a polymer compound, simply reducing the surface roughness of the negative electrode plate to 0.4 mm or less is ineffective in suppressing stratification, and it is difficult to suppress the elution of the polymer compound into the electrolyte. Reducing the surface roughness of the negative electrode plate without increasing the pull-out load does not increase the degree of adhesion between the separator and the negative electrode plate, and is insufficient to suppress stratification of the electrolyte and the elution of the polymer compound.

[0022] If the pull-out load is less than 1.5 times the weight of the negative electrode, it is difficult to sufficiently increase the degree of adhesion between the separator and the negative electrode, even if the surface roughness of the negative electrode is sufficiently reduced. The pull-out load should be at least 1.5 times the weight of the negative electrode, but 1.8 times or more is preferable, and it may be 2.8 times or more, or 3.5 times or more. Note that a pull-out load of 10 times or more of the weight of the negative electrode poses manufacturing difficulties, so the upper limit of the pull-out load is 10 times the weight of the negative electrode.

[0023] If the surface roughness of the negative electrode plate exceeds 0.4 mm, it is difficult to sufficiently increase the degree of adhesion between the separator and the negative electrode plate even if the pull-out load is 1.5 times or more of the plate's own weight. The surface roughness of the negative electrode plate should be 0.4 mm or less, but it may also be 0.3 mm or less, 0.2 mm or less, or 0.15 mm or less.

[0024] The lead acid battery may be either a valve regulated (sealed) lead acid battery (VRLA) or a flooded (vented) lead acid battery.

[0025] In this specification, the pull-out load when the electrode plate group is pulled out from the battery case, the surface roughness of the negative electrode plate, and the content of the polymer compound in the negative electrode material are determined for a fully charged lead-acid battery and a negative electrode plate in the electrode plate group removed from the battery case, respectively.

[0026] <Fully charged state> 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).

[0027] 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.

[0028] <Weight of electrode plate group> The dead weight of the plate assembly is measured using the following procedure. First, the top cover of the lead-acid battery is cut off to disassemble the battery, then all of the electrolyte in the battery case is drained and the plate assembly is removed. Next, the dead weight (W1) of the removed plate assembly is measured using a balance while it is soaked with electrolyte (the plates are wet). In this way, the dead weight (W1) of the plate assembly is measured. The plate assembly whose dead weight is measured includes the positive plate, negative plate, and other components of the plate assembly (such as separators and straps).

[0029] <Pull-out load> The pull-out load when the electrode plate group is pulled out from the battery case is measured using the following procedure. First, the electrode plate group whose weight has been measured as described above is returned to the battery case, and a hook is attached to a part of the electrode plate group (for example, a strap portion) to pull out the electrode plate group. At this time, a digital force gauge is used to measure the load when the electrode plate group is pulled out from the battery case. The maximum value of the measured load is taken as the pull-out load (W2) of the electrode plate group. Then, the ratio of the pull-out load (W2) to the weight (W1) of the electrode plate group (hereinafter also referred to as the "pull-out load ratio") is calculated.

[0030] <Surface roughness of negative electrode plate> Measurement is performed using the following procedure. First, the electrode group removed from the fully charged lead-acid battery as described above is disassembled and the negative electrode plate is removed. 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 change in color 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 the negative electrode plate contains an adhesive material, the surface roughness is measured without removing the adhesive material.

[0031] As shown in FIG. 2, the negative electrode plate 3 is generally rectangular in shape, having a first side 31 and a second side 32 that face each other, and a third side 33 and a fourth side 34 that intersect with these sides and face each other.

[0032] Next, the portion of the negative electrode plate 3 containing the negative electrode material is divided into nine roughly equal-sized sections, 3 rows and 3 columns, by two lines L1 and L2 extending from the third side to the fourth side and two lines L3 and L4 extending from the first side to the second side. The maximum height roughness Rz is measured in a 5 mm x 7.5 mm rectangular area A1 to A9 (short sides parallel to L1 and L2, long sides parallel to L3 and L4) at the center of each section. The maximum height roughness Rz is the difference (Rv + Rp) between the most recessed portion (maximum valley depth Rv) and the most protruding portion (maximum peak height Rp). The maximum height roughness Rz is measured using a microscope (e.g., Keyence VK-X100 series). The surface roughness of the negative electrode plate is calculated as the average of the 18 maximum height roughness Rz values ​​measured on both sides of A1 to A9.

[0033] When the electrode plate assembly has two or more negative electrode plates, it is sufficient that at least one negative electrode plate satisfies the above conditions. However, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of negative electrode plates included in the electrode plate assembly satisfy the above conditions. The proportion of negative electrode plates that satisfy the above conditions among the negative electrode plates included in the electrode plate assembly is 100% or less. It is preferable that all negative electrode plates included in the electrode plate assembly satisfy the above conditions.

[0034] Furthermore, when a lead-acid battery has two or more electrode plate groups, it is sufficient that at least one of the electrode plate groups satisfies the above-mentioned conditions. However, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the electrode plate groups included in the lead-acid battery satisfy the above-mentioned conditions. Of the electrode plate groups included in the lead-acid battery, the proportion of electrode plate groups that satisfy the above-mentioned conditions is 100% or less. It is preferable that all of the electrode plate groups included in the lead-acid battery satisfy the above-mentioned conditions.

[0035] Hereinafter, each of the main components of the lead-acid battery according to the embodiment of the present invention will be described, but the present invention is not limited to the following embodiment.

[0036] [Negative electrode] A negative electrode plate typically includes a negative electrode current collector in addition to a negative electrode material. A negative electrode plate can be formed by coating or filling a negative electrode paste onto a negative electrode current collector, aging and drying the paste to produce an unformed negative electrode plate, and then chemically forming the unformed negative electrode plate. The negative electrode paste is prepared, for example, by kneading lead powder, a polymer compound, optionally other additives, water, and sulfuric acid (or an aqueous sulfuric acid solution). The unformed negative electrode plate may be aged at a temperature higher than room temperature and at a high humidity.

[0037] When applying or filling the negative electrode paste onto the negative electrode current collector, the negative electrode paste is pressed against the negative electrode current collector using a jig with as few irregularities as possible so that the surface roughness of the negative electrode plate is 0.4 mm or less. This allows the surface roughness of the negative electrode material to be controlled to 0.4 mm or less. However, the method for controlling the surface roughness is not particularly limited, and for example, the surface roughness may be controlled by polishing the surface of the unformed negative electrode plate after aging.

[0038] 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 container 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.

[0039] (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.

[0040] The lead alloy used for the negative electrode current collector may be any of a Pb-Sb alloy, a Pb-Ca alloy, and a Pb-Ca-Sn alloy. These lead or lead alloys may further contain at least one additive element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, and the like. The negative electrode current collector may have a surface layer. The surface layer and the inner layer of the negative electrode current collector may have different compositions. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on an edge portion of the negative electrode current collector. The surface layer of the edge portion may contain Sn or an Sn alloy.

[0041] (Negative electrode material) The negative electrode material contains a negative electrode active material (specifically, lead or lead sulfate) that generates capacity through a redox reaction and a polymer compound. The negative electrode material may further contain an additive. Examples of the additive include, but are not limited to, an organic shrinkage inhibitor, a carbonaceous material, and barium sulfate. The negative electrode active material in a charged state is spongy lead.

[0042] (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 Contains repeating alkylene units. OxyC 2-4 The alkylene unit is -O-R1- (R1 is C 2-4 It is a unit represented by the formula (1).

[0043] Under condition (i), the peak between 3.2 ppm and 3.8 ppm is oxy-C. 2-4It is derived from an alkylene unit. In other words, a polymer compound satisfying the condition (ii) is also a polymer compound satisfying the condition (i). However, a polymer compound satisfying the condition (i) is not a polymer compound containing an 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.

[0044] The polymeric compounds may include oxygen atoms attached to end groups and -CH2- and / or -CH< groups attached 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 sum of the 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, for example, 50% or more, or may be 80% or more, 85% or more, or may be 90% or more. 2-4 It contains many alkylene units in its molecule. This makes it easier for the polymer compound to take on a linear structure, which is thought to make it easier to thinly cover the lead surface. This makes it possible to more effectively reduce liquid loss. For example, if the polymer compound has an -OH group at the end and also has a -CH2- group or -CH< group bonded to the oxygen atom of this -OH group, 1 In 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.

[0045] The polymer compound is OxyC 2-4 It is preferable that the alkylene unit contains a repeating structure. 2-4 When a polymer compound containing a repeating structure of alkylene units is used, it is thought that the polymer compound is more likely to adsorb to lead, and that the polymer compound is more likely to take on a linear structure, making it easier to thinly cover the lead surface. 2-4It may contain an alkylene unit, and two or more kinds of oxy C 2-4 It may contain an alkylene unit. 2-4 Polymer compounds having a repeating structure of alkylene units also include those classified as surfactants (for example, nonionic surfactants).

[0046] Oxy C 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.

[0047] Oxy C 2-4 The alkylene unit may be, for example, an oxypropylene unit (-O-CH(-CH3)-CH2-). That is, the polymer compound may contain a repeating structure of oxypropylene units. Such a polymer compound has high adsorption properties for lead but does not excessively adhere to the lead surface. Therefore, it can effectively reduce liquid loss.

[0048] Oxy C 2-4 The alkylene unit may be, for example, an oxyethylene unit (-O-CH2-CH2-). That is, the polymer compound may contain a repeating structure of oxyethylene units. The repeating structure of oxyethylene units has high hydrophilicity, and can selectively adsorb lead. This makes it easy to control the adsorption of the polymer compound to lead.

[0049] The polymer compound is OxyC 2-4 It may contain at least one selected from the group consisting of a hydroxy compound having a repeating structure of alkylene units (hereinafter also referred to as hydroxy compound C), an etherified product of hydroxy compound C, and an esterified product of hydroxy compound C.

[0050] wherein the hydroxy compound C is polyC 2-4 Alkylene glycol, oxy C 2-4 PolyC, a copolymer and polyol containing repeating alkylene units 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 liquid loss can be more effectively suppressed.

[0051] Oxy C 2-4 Copolymers containing repeating alkylene units include different oxy C 2-4 Copolymers containing alkylene units, polyC 2-4 Alkylene glycol alkyl ether, poly C carboxylic acid 2-4 alkylene glycol esters, etc. The copolymer may be a block copolymer.

[0052] Polyol Poly C 2-4 Examples of polyols constituting the alkylene oxide adduct include aliphatic polyols, alicyclic polyols, aromatic polyols, and heterocyclic polyols. Aliphatic polyols and alicyclic polyols (e.g., polyhydroxycyclohexane, polyhydroxynorbornane, etc.) are preferred because the polymer compound can be easily spread thinly over the lead surface, and aliphatic polyols are particularly preferred. Examples of aliphatic polyols include aliphatic diols and polyols with a triol or higher (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, for example, C 5-14 Alkylene glycol or C 5-10 It may be alkylene glycol. Examples of sugars or sugar alcohols include sucrose, erythritol, xylitol, mannitol, sorbitol, etc. The sugars or sugar alcohols may have either a chain structure or a cyclic structure.

[0053] In the polyalkylene oxide adduct of polyol, the alkylene oxide is the oxy-C of the polymer compound. 2-4 Corresponding to an alkylene unit, at least C 2-4 The polyol contains an alkylene oxide. From the viewpoint that the polymer compound is likely to have a linear structure, the polyol is preferably a diol.

[0054] The etherified product of hydroxy compound C has -OR2 groups (where R2 is an organic group) resulting from etherification of at least some of the terminal -OH groups of hydroxy compound C (-OH groups consisting of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom). 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 may be an -OH group and the other terminal may be an -OR2 group.

[0055] The ester of hydroxy compound C has an -OC(=O)-R3 group, where at least some of the terminal -OH groups of hydroxy compound C are esterified (wherein R3 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 may be an -OH group, and the other terminal may be an -OC(=O)-R3 group.

[0056] Examples of the organic groups R2 and R3 include hydrocarbon groups. The hydrocarbon groups may have a substituent (such as a hydroxy group, an alkoxy group, or a carboxy group). The hydrocarbon groups may be aliphatic, alicyclic, or aromatic. The aromatic hydrocarbon groups and alicyclic hydrocarbon groups may have an aliphatic hydrocarbon group (such as an alkyl group, an alkenyl group, or an alkynyl group) as a substituent. The aliphatic hydrocarbon group as a substituent may have, for example, 1 to 30 carbon atoms, 1 to 20 carbon atoms, 1 to 10 carbon atoms, 1 to 6 carbon atoms, or 1 to 4 carbon atoms.

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

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

[0059] Examples of alicyclic hydrocarbon groups include cycloalkyl groups (cyclopentyl, cyclohexyl, cyclooctyl, etc.), cycloalkenyl groups (cyclohexenyl, cyclooctenyl, etc.), etc. Alicyclic hydrocarbon groups also include hydrogenated aromatic hydrocarbon groups.

[0060] 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.

[0061] 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 because they facilitate thin adhesion of the polymer compound to the lead surface.

[0062] 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.

[0063] 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 It may be an alkenyl group, C 2-22 Alkenyl group or C 2-20 It may be an alkenyl group, C 10-20 It may also be an alkenyl group.

[0064] Among the polymer compounds, at least one selected from the group consisting of etherified products of hydroxy compound C and esterified products of hydroxy compound C is preferred, and these polymer compounds preferably have a repeating structure of oxypropylene units or a repeating structure of oxyethylene units.

[0065] The polymer compound may have one or more hydrophobic groups. Examples of the hydrophobic group include the hydrocarbon groups exemplified as the organic group R2 or R3, such as aromatic hydrocarbon groups, alicyclic hydrocarbon groups, and long-chain aliphatic hydrocarbon groups. At least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The action of such hydrophobic groups prevents excessive coating of the polymer compound on the lead surface.

[0066] Examples of long-chain aliphatic hydrocarbon groups include alkyl groups and alkenyl groups having 8 or more carbon atoms, preferably 12 or more carbon atoms, and more preferably 16 or more carbon atoms. Polymer compounds having long-chain aliphatic hydrocarbon groups are less likely to excessively adsorb lead, further enhancing the effect of suppressing resistance increases during discharge. At least one of the hydrophobic groups may be 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.

[0067] A polymer compound having both hydrophilic and hydrophobic groups corresponds to a nonionic surfactant. The hydrophilic group may be a repeating structure of an oxyethylene unit. The repeating structure of an oxyethylene unit has high hydrophilicity. The balance between the hydrophobic group and the repeating structure of an oxyethylene unit allows selective adsorption of lead while preventing excessive coverage of the lead surface. Examples of polymer compounds corresponding to such nonionic surfactants include polyoxypropylene-polyoxyethylene block copolymers, etherified products of hydroxy compounds having repeating structures of oxyethylene units, and esterified products of hydroxy compounds having repeating structures of oxyethylene units. These can ensure high adsorption to lead even with relatively low molecular weights (e.g., Mn of 300 or more or 400 to 1000). 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.

[0068] Examples of polymer compounds that correspond to nonionic surfactants include etherified polyethylene glycol (such as alkyl ethers), esterified polyethylene glycol (such as carboxylic acid esters), etherified polyethylene oxide adducts of the above polyols (such as alkyl ethers), and esterified polyethylene oxide adducts of the above polyols (such as carboxylic acid esters). Specific examples include, but are not limited to, polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene coconut oil fatty acid sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

[0069] The HLB of the polymer compound classified as a surfactant is preferably 4 or more, more preferably 4.3 or more, from the viewpoint of further reducing the loss of the electrolyte solution. From the viewpoint of suppressing an increase in resistance during discharge, 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.

[0070] Oxy C 2-4 It is also preferable that the repeating alkylene unit contains at least a repeating oxypropylene unit. 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 1In 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 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). 2-4 Examples 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 a repeating structure of oxypropylene units include, but are not limited to, 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)), polypropylene glycol carboxylates (such as polypropylene glycol acetates) in which the above R3 is an alkyl having 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 the polymer compound, the proportion of oxypropylene units is, for example, 5 mol% or more, and 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, 75 mol% or less, or 60 mol% or less.

[0074] From the viewpoint of further improving the cycle life, the content of the polymer compound in the negative electrode material is preferably 500 ppm by mass or less, and from the viewpoint of further suppressing the loss of the electrolyte, the content of the polymer compound in the negative electrode material is preferably 30 ppm by mass or more.

[0075] The content (by mass) of the polymer compound in the negative electrode material may be 30 ppm or more and 500 ppm or less, 30 ppm or more and 400 ppm or less, 30 ppm or more and 200 ppm or less, 50 ppm or more and 500 ppm or less, 50 ppm or more and 400 ppm or less, 50 ppm or more and 200 ppm or less, 80 ppm or more and 500 ppm or less, 80 ppm or more and 400 ppm or less, or 80 ppm or more and 200 ppm or less.

[0076] The polymer compound preferably contains a compound having a number average molecular weight (Mn) of not more than 10,000. In this case, the thickness of the coating of the polymer compound that covers the surfaces of the lead and lead sulfate can be further reduced.

[0077] The polymer compound preferably contains a polymer compound with an Mn of 500 or more. In this case, higher adsorption to lead can be ensured, and the lead surface can be easily covered with the polymer compound. This can further reduce the amount of electricity in overcharge. Therefore, the effect of suppressing the progress of the loss of electrolyte can be enhanced.

[0078] The negative electrode material may contain one or more polymer compounds. The negative electrode material may also contain two or more polymer compounds with different Mn. That is, the molecular weight distribution of the polymer compound may have multiple Mn peaks.

[0079] The Mn of the polymer compound may be 500 or more (or 1000 or more) and 10,000 or less, 500 or more (or 1000 or more) and 5,000 or less, 500 or more (or 1000 or more) and 4,000 or less, 500 or more (or 1000 or more) and 3,000 or less, or 500 or more (or 1000 or more) and 2,500 or less.

[0080] <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.

[0081] (organic shrinkage preventer) The organic shrinkage preventer is an organic compound that has 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. As the organic shrinkage preventer, for example, at least one selected from the group consisting of lignin compounds and synthetic organic shrinkage preventers may be used.

[0082] 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)).

[0083] The synthetic organic expander used in lead-acid batteries is usually an organic condensation product (hereinafter simply referred to as a condensation product). A condensation product is a synthetic product that can be obtained by utilizing a condensation reaction. The condensation product may contain an aromatic compound unit (hereinafter also referred to as an aromatic compound unit). The aromatic compound unit refers to a unit derived from an aromatic compound incorporated into the condensation product. In other words, the aromatic compound unit is a residue of an aromatic compound. The condensation product may contain one type of aromatic compound unit, or two or more types.

[0084] Examples of condensates include condensates of aromatic compounds with aldehyde compounds. Such condensates can be synthesized by reacting an aromatic compound with an aldehyde compound. Condensates containing sulfur can be obtained by reacting an aromatic compound with an aldehyde compound in the presence of a sulfite or by using an aromatic compound containing sulfur (e.g., bisphenol S) as the aromatic compound. For example, the sulfur content in the condensate can be adjusted by adjusting at least one of the amount of sulfite and the amount of the aromatic compound containing sulfur. This method can also be used when using other raw materials. One or more aromatic compounds may be condensed to obtain a condensate. The aldehyde compound may be an aldehyde (e.g., formaldehyde) or a condensate (or polymer) of an aldehyde. Examples of aldehyde condensates (or polymers) include paraformaldehyde, trioxane, and tetraoxymethylene. The aldehyde compounds may be used alone or in combination. Formaldehyde is preferred from the viewpoint of high reactivity with aromatic compounds.

[0085] The aromatic compound may have a sulfur-containing group. That is, the condensate may be an organic polymer containing multiple aromatic rings in the molecule and containing elemental sulfur as a sulfur-containing group. The sulfur-containing group may be directly bonded to the aromatic ring of the aromatic compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group, which are stable, is preferred. The sulfonic acid group may exist in an acid form or in a salt form such as a sodium salt.

[0086] Examples of aromatic rings that aromatic compounds have 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), etc. Examples of such structures include bisarene structures (biphenyl, bisphenylalkane, bisphenylsulfone, etc.).

[0087] Examples of aromatic compounds include compounds having the above-mentioned aromatic ring and a functional group (such as a hydroxy group or an amino group). The functional group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having the functional group. The hydroxy group also includes a salt of the hydroxy group (-OMe). The amino group also includes a salt of the amino group (a salt with an anion). Examples of Me include alkali metals (such as Li, K, and Na) and metals of Group 2 of the periodic table (such as Ca and Mg). The aromatic compound may have a sulfur-containing group and a substituent other than the above-mentioned functional group (such as an alkyl group or an alkoxy group) on the aromatic ring.

[0088] The aromatic compound that is the source of the aromatic compound unit may be at least one selected from the group consisting of bisarene compounds and monocyclic aromatic compounds.

[0089] Examples of bisarene compounds include bisphenol compounds, hydroxybiphenyl compounds, and 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). Among these, bisphenol compounds are preferred.

[0090] The bisphenol compound is preferably bisphenol A, bisphenol S, bisphenol F, or the like. For example, the bisphenol compound may include at least one selected from the group consisting of bisphenol A and bisphenol S. By using bisphenol A or bisphenol S, an excellent shrinkage prevention effect can be obtained for the negative electrode material.

[0091] The bisphenol compound may have a bisphenol skeleton, and the bisphenol skeleton may have a substituent. That is, bisphenol A may have a bisphenol A skeleton, and the skeleton may have a substituent. Bisphenol S may have a bisphenol S skeleton, and the skeleton may have a substituent.

[0092] Preferred monocyclic aromatic compounds include hydroxymonoarene compounds and aminomonoarene compounds, with hydroxymonoarene compounds being particularly preferred.

[0093] Examples of the hydroxymonoarene compound include a hydroxynaphthalene compound and a phenol compound. For example, it is preferable to use a phenolic compound, such as a phenolsulfonic acid compound (phenolsulfonic acid or its substituted derivatives). As mentioned above, the phenolic hydroxy group also includes a salt of the phenolic hydroxy group (-OMe).

[0094] Examples of the aminomonoarene compound include aminonaphthalene compounds and aniline compounds (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc.).

[0095] The content of the organic shrinkage inhibitor in the negative electrode material is preferably, for example, 0.005% by mass or more, while from the viewpoint of suppressing a decrease in charge acceptance, the content of the organic shrinkage inhibitor in the negative electrode material is preferably 0.3% by mass or less.

[0096] (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.

[0097] 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.

[0098] (barium sulfate) 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.

[0099] ≪Analysis≫ The following describes the analysis method for the polymer compounds and additives contained in the negative electrode material. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain the negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate. The washing is continued until a pH test paper is pressed against the washed negative electrode surface 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, it 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 then crushed as necessary and subjected to analysis.

[0100] (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.

[0101] 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.

[0102] 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

[0103] 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.

[0104] In addition, in qualitative analysis, 1 When calculating the integral value of a peak in a H-NMR spectrum, 1 In the H-NMR spectrum, two points without significant signals are determined on either side of the peak, and the line connecting these two points is used as the baseline to calculate each integral value. For example, for a peak with a chemical shift in the range of 3.2 ppm to 3.8 ppm, the line connecting the two points at 3.2 ppm and 3.8 ppm in the spectrum is used as the baseline. For example, for a peak with a chemical shift in the range of more than 3.8 ppm but not more than 4.0 ppm, the line connecting the two points at 3.8 ppm and 4.0 ppm in the spectrum is used as the baseline.

[0105] (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°C Inlet temperature: 240℃ Detector temperature: 240℃ Carrier gas: He (flow rate: 50 mL / min) Injection volume: 1μL~2μL

[0106] (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.

[0107] (1-2) Quantitative analysis of polymer compounds An appropriate amount of the chloroform-soluble matter was dissolved in deuterated chloroform together with tetrachloroethane (TCE) whose mr (g) was measured with an accuracy of ±0.0001 g. 1 Measure the H-NMR spectrum. Calculate the integral value (Sa) of the peak present in the chemical shift range of 3.2 to 3.8 ppm and the integral value (Sr) of the peak derived from TCE, and calculate the mass-based content Cn (ppm) of the polymer compound in the negative electrode material using the following formula:

[0108] Cn=Sa / Sr×Nr / Na×Ma / Mr×mr / m×1000000 (wherein Ma is the molecular weight of a structure whose chemical shift shows a peak in the range of 3.2 to 3.8 ppm (more specifically, oxy C 2-4 where Nr is the number of hydrogen atoms bonded to the carbon atoms in the main chain of the repeating structure, Nr is the number of hydrogen atoms contained in the molecule of the reference material, and Mr is the molecular weight of the reference material, respectively. m (g) is the mass of the negative electrode material used for extraction. In this analysis, the reference substance is TCE, so Nr=2, Mr=168, and m=100.

[0109] For example, when the polymer compound is polypropylene glycol, Ma is 58 and Na is 3. When the polymer compound is polyethylene glycol, Ma is 44 and Na is 4. In the case of a copolymer, Na and Ma are values ​​obtained by averaging the Na value and Ma value of each monomer unit using the molar ratio (mol%) of each monomer unit contained in the repeating structure.

[0110] 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.

[0111] (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.

[0112] 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)

[0113] (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-control agent. Next, if necessary, the first organic shrink-control agent and the second organic shrink-control agent are separated from the extract. For each of the separated organic shrink-control agents, insoluble components are removed 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-control agent (hereinafter referred to as sample B) is obtained by drying.

[0114] 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.

[0115] If the extract contains multiple organic shrink-regulating agents, their separation is performed as follows. First, the extract is analyzed by infrared spectroscopy, NMR, and / or GC-MS to determine whether it contains multiple organic shrink-regulating agents. Next, the extract is analyzed by GPC to measure its molecular weight distribution. If the multiple organic shrink-regulating agents can be separated by molecular weight, the organic shrink-regulating agents are separated by column chromatography based on their molecular weight differences. If separation based on molecular weight differences is difficult, the organic shrink-regulating agents are separated by precipitation separation, taking advantage of the differences in solubility depending on the type and / or amount of functional groups possessed by the organic shrink-regulating agents. For example, to separate two organic shrink-regulating agents, the extract is dissolved in aqueous NaOH solution, and then a sulfuric acid solution is added dropwise to adjust the pH of the mixture to flocculate and separate one of the organic shrink-regulating agents. The separated material is then dissolved again in aqueous NaOH solution, and the insoluble components are removed by filtration as described above. The remaining solution after separating one of the organic shrink-regulating agents is then concentrated. The resulting concentrate contains the other organic shrinkage inhibitor, and the insoluble components are removed from the concentrate by filtration as described above.

[0116] (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.

[0117] 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.

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

[0119] The resulting solids are dispersed in water to form a dispersion, and then components other than the carbonaceous material and barium sulfate (e.g., reinforcing materials) 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 is dried together with the filtered sample 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 (Mm) is measured by subtracting the mass of the membrane filter from the total mass of the dried mixed sample (hereinafter referred to as Sample C) and the membrane filter. Sample C is then placed in a crucible together with the membrane filter and incinerated at 1300°C or higher. 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 (MB). The mass of the carbonaceous material is calculated by subtracting the mass MB from the mass Mm.

[0120] [Positive electrode] The positive electrode plate can be classified into a paste type, a clad type, etc. Either a paste type or a clad type positive electrode plate may be used.

[0121] A paste-type positive electrode plate includes a positive electrode material and a positive electrode current collector. The positive electrode plate can be formed by applying or filling a positive electrode paste onto a positive electrode current collector, aging and drying the positive electrode paste to produce an unformed positive electrode plate, and then chemically forming the unformed positive electrode plate. The positive electrode paste is prepared, for example, by kneading lead powder, optional additives, water, and sulfuric acid (or an aqueous sulfuric acid solution). The unformed positive electrode plate may be aged at a temperature higher than room temperature and at high humidity.

[0122] A clad type positive electrode plate comprises a plurality of porous tubes, a core metal inserted into each tube, a current collecting part connecting the plurality of core metals, a positive electrode material filled into the tube into which the core metal is inserted, and a connecting seat connecting the plurality of tubes.

[0123] The formation can be performed by immersing an electrode plate assembly including unformed positive plates in an electrolyte containing sulfuric acid in a battery container of a lead-acid battery and charging the electrode plate assembly, but the formation may also be performed before assembling the lead-acid battery or the electrode plate assembly.

[0124] (Positive electrode current collector) The positive electrode current collector of the paste-type positive electrode plate 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. Using a lattice-shaped current collector as the positive electrode current collector is preferable because it makes it easier to support the positive electrode material. The positive electrode current collector may have a surface layer. The surface layer and the inner layer of the positive electrode current collector may have different compositions. The surface layer may be formed on a part of the positive electrode current collector. The surface layer may be formed only on the lattice portion, only on the lug portion, or only on the frame portion of the positive electrode current collector.

[0125] In the clad type positive electrode plate, the combination of the core metal and the current collecting portion corresponds to the positive electrode current collector.

[0126] 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.

[0127] (Positive electrode material) The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that generates capacity through an oxidation-reduction reaction. The positive electrode material may contain additives as needed. In a clad positive plate, the positive electrode material is the positive plate excluding the tube, core, current collector, and connecting seat.

[0128] [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.

[0129] 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.

[0130] 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.

[0131] 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.

[0132] [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.

[0133] A nonwoven fabric is a mat of intertwined fibers, not 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. Among these, glass fibers are preferred. The nonwoven fabric may also contain components other than fibers, such as acid-resistant inorganic powders and polymers as binders.

[0134] 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 may be at least one selected from the group consisting of polymer powder and oil.

[0135] The separator may be composed of 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.

[0136] 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.

[0137] In this specification, the up-down direction of a lead-acid battery or its components (electrode plates, battery case, separator, etc.) refers to the up-down direction in the vertical direction of the lead-acid battery when the lead-acid battery is in use. Each of the positive and negative electrode 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 electrode plate so as to protrude laterally, but in most lead-acid batteries, the lug is usually provided on the top of the electrode plate so as to protrude upward.

[0138] [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.

[0139] FIG. 1 shows the external appearance 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 includes a positive electrode terminal 16 and a negative electrode terminal 17. The lid 15 is provided with a vent plug 18 for each cell chamber. When rehydrating, the vent plug 18 is removed and rehydration liquid is added. The vent plug 18 may have a function of venting gas generated in the cell chambers 14 to the outside of the battery.

[0140] The electrode plate group 11 is formed by alternately stacking multiple negative electrode plates 3 and multiple positive electrode plates 2 with separators 4 interposed between them. The separators 4 are bag-shaped and individually package the positive electrode plates 2. In a cell chamber 14 located at one end of the battery case 12, a positive electrode shelf 6 that connects the ears 2a of multiple positive electrode plates 2 in parallel is connected to a feedthrough connector 8, and a negative electrode shelf 5 that connects the ears 3a of multiple negative electrode plates 3 in parallel is connected to a negative electrode pole 7. The negative electrode pole 7 is connected to a negative electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, a positive electrode pole 9 is connected to the positive electrode shelf 6, and a feedthrough connector 8 is connected to the negative electrode shelf 5. The positive electrode pole 9 is connected to a positive electrode terminal 16 outside the lid 15. Each of the through-connectors 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plate groups 11 of adjacent cell chambers 14 in series.

[0141] The positive electrode shelf 6 is formed by welding together the ears 2a provided on the top of each positive electrode plate 2 using a cast-on-strap method or a burning method. The negative electrode shelf 5 is also formed by welding together the ears 3a provided on the top of each negative electrode plate 3 in the same manner as the positive electrode shelf 6.

[0142] 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 including, for example, 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.

[0143] In this specification, the cycle life and the overcharge quantity of electricity are evaluated according to the following procedures. The test battery used for the evaluation has a rated voltage of 2 V / cell and a rated 20-hour rate capacity of 60 Ah. The electrode plate group has seven positive electrode plates and eight negative electrode plates stacked alternately, and the positive electrode plates are housed in a pouch-shaped separator.

[0144] <PSOC cycle test> The following steps 1 to 7 are repeated in a water bath at 25°C ± 3°C until the battery reaches a lifespan determination. A combination of steps 2 and 3 is counted as one cycle, and the number of cycles until the battery reaches a lifespan determination is measured. The battery is determined to have reached its lifespan when the discharge end voltage in step 1 or step 3 becomes 1.67 V / cell or less. The more cycles of steps 2 and 3 combined, the better the cycle life under PSOC.

[0145] Step 1: Discharge at a constant current of 12.0A for 2.5 hours Step 2: Charge for 40 minutes at a constant voltage of 2.4V / cell and a maximum current of 21.0A. Step 3: Discharge at a constant current of 21.0 A for 30 minutes Step 4: Repeat step 2 and step 3 85 times. Step 5: Charge for 18 hours at a constant voltage of 2.67V / cell and a maximum current of 6.0A. Step 6: Discharge at a constant current of 3.0A down to 1.75V / cell Step 7: Charge for 24 hours at a constant voltage of 2.67V / cell and a maximum current of 15.0A. After step 7, return to step 1

[0146] <High temperature light load test> The above PSOC cycle test is performed 100 cycles, and then a light load test of 1 minute of discharge and 10 minutes of charge is performed in a water tank at 75°C ± 3°C with the battery stopped in the charge state of step 5 (i.e., stratified conditions) for 1220 cycles, and the overcharge quantity of electricity is calculated by subtracting the discharge quantity of electricity from the charge quantity of electricity below. Specifically, the combination of the following steps A and B is repeated 1220 cycles.

[0147] Step A: Discharge at a constant current of 25A for 1 minute Step B: Charge for 10 minutes at a constant voltage of 2.47V / cell and a maximum current of 25A.

[0148] The overcharge quantity of electricity (Ah) per cycle is calculated by adding up and averaging the overcharge quantity of electricity (charge quantity of electricity - discharge quantity of electricity) for each cycle up to 1220 cycles. The smaller the overcharge quantity of electricity, the smaller the amount of electrolyte loss.

[0149] The cycle life and the amount of overcharge electricity are both evaluated as a percentage (%), with the value for Battery B1 (described below) being 100%. The larger the percentage, the better the cycle life, and the smaller the percentage, the better the amount of overcharge electricity.

[0150] The valve-regulated lead-acid battery according to the present invention will be described below.

[0151] (1) A lead-acid battery, a battery comprising: an electrode plate group; an electrolyte; and a battery case that accommodates the electrode plate group and the electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate, The pull-out load when the electrode plate group is pulled out from the battery case is 1.5 times or more the weight of the electrode plate group itself, The surface roughness of the negative electrode plate is 0.4 mm or less, the negative electrode plate includes a negative electrode material, the negative electrode material includes a polymer compound, The polymer compound is measured using deuterated chloroform as a solvent. 1 A lead-acid battery having a peak in the range of 3.2 ppm to 3.8 ppm in the chemical shift of its H-NMR spectrum.

[0152] (2) The polymer compound is oxy C 2-4 The lead-acid battery according to (1) above, having a repeating structure of alkylene units.

[0153] (3) A lead-acid battery, a battery comprising: an electrode plate group; an electrolyte; and a battery case that accommodates the electrode plate group and the electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate, The pull-out load when the electrode plate group is pulled out from the battery case is 1.5 times or more the weight of the electrode plate group itself, The surface roughness of the negative electrode plate is 0.4 mm or less, the negative electrode plate includes a negative electrode material, the negative electrode material includes a polymer compound, The polymer compound is oxy C 2-4 A lead-acid battery having a repeating structure of alkylene units.

[0154] (4) The lead-acid battery according to (2) or (3), wherein the polymer compound contains at least one selected from the group consisting of a hydroxy compound having the repeating structure, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound.

[0155] (5) The hydroxy compound is polyC 2-4 Alkylene glycol, oxy C 2-4 Copolymers containing repeating alkylene units and polyol polyC 2-4 The lead-acid battery according to (4) above, wherein the compound is at least one selected from the group consisting of alkylene oxide adducts.

[0156] (6) the oxy C 2-4 The lead-acid battery according to any one of the above (2) to (5), wherein the alkylene unit is an oxypropylene unit.

[0157] (7) the oxy C 2-4 The lead-acid battery according to any one of the above (2) to (5), wherein the alkylene unit is an oxyethylene unit.

[0158] (8) the polymer compound comprises an oxygen atom bonded to a terminal group and a —CH— group and / or a —CH< group bonded to the oxygen atom; The aforementioned 1 The lead-acid battery according to any one of (1) to (7) above, wherein 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 atoms of the -CH- groups, and the integral value of the peak due to the hydrogen atoms of the -CH< groups is 85% or more.

[0159] (9) The polymer compound has one or more hydrophobic groups, The lead-acid battery according to any one of the above (1) to (8), wherein at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

[0160] (10) The lead-acid battery according to any one of (1) to (9) above, wherein the polymer compound is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene cocoate sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

[0161] (11) The lead-acid battery according to any one of (1) to (10) above, wherein the content of the polymer compound in the negative electrode material is in the range of 30 ppm to 500 ppm by mass.

[0162] (12) The lead-acid battery according to any one of (1) to (11) above, wherein the polymer compound includes a compound having a number average molecular weight of 10,000 or less.

[0163] (13) The lead-acid battery according to any one of (1) to (12) above, wherein the polymer compound includes a compound having a number average molecular weight of 500 or more.

[0164] [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.

[0165] 《Lead acid battery R1~R5》 (1) Preparation of lead-acid batteries (a) Preparation of the negative electrode plate The raw material lead powder, predetermined amounts of sodium lignosulfonate (organic shrinkage inhibitor), barium sulfate, carbon black, and the polymer compound polyethylene glycol oleate (PEG oleate) are mixed with an appropriate amount of sulfuric acid aqueous solution to obtain a negative electrode paste. The contents of the polymer compounds in the negative electrode material obtained by the above-mentioned procedure are shown in Table 1, and the components are mixed so that the contents of sodium lignosulfonate are 0.1 mass%, barium sulfate are 0.4 mass%, and carbon black are 0.2 mass%. The density of the negative electrode material contained in a fully charged lead-acid battery after chemical formation is 3.6 g / cm. 3 The concentration and amount of the sulfuric acid aqueous solution are adjusted so that the negative electrode paste is filled into the mesh of an expanded grid made of a Pb-Ca-Sn alloy, and the grid is aged and dried to obtain an unformed negative electrode plate.

[0166] When filling the mesh of the expanded grid with negative electrode paste, the paste is pressed with a conventional jig. The surface roughness of the negative electrode plate measured using the procedure described above is greater than 0.4 mm (0.5 mm).

[0167] (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, which is then filled into the mesh of a Pb-Ca-Sn alloy expanded grid, aged, and dried to obtain an unformed positive electrode plate.

[0168] (c) Preparation of test battery The test battery has a rated voltage of 2V / cell and a rated 20-hour rate capacity of 60Ah. The electrode plate assembly of the test battery consists of seven positive and eight negative plates, with the positive plates housed in a pouch-shaped separator. The pouch-shaped separator is made of a polyethylene microporous membrane. The electrode plate assembly is housed in a polypropylene battery case together with an electrolyte (aqueous sulfuric acid solution) and subjected to chemical formation in the battery case to produce a liquid lead-acid battery. The withdrawal load ratio W2 / W1, determined by the previously described method, is set to 1.0, and the specific gravity of the electrolyte at 20°C in a fully charged lead-acid battery is set to 1.28. The withdrawal load ratio W2 / W1 is adjusted by inserting the electrode plate assembly with spacers or compressing the electrode plate assembly with a specified jig when housing the electrode plate assembly in the battery case so that the W2 / W1 value of the lead-acid battery measured after disassembly is the value shown in Tables 1 to 8.

[0169] (2) Evaluation The PSOC cycle test and high-temperature light load test were carried out using the procedures described above, and the cycle life in the PSOC cycle test and the overcharge quantity of electricity in the high-temperature light load test were evaluated. The results are shown in Table 1.

[0170] 《Lead acid battery R6~R10》 Lead-acid batteries are fabricated and evaluated in the same manner as lead-acid batteries R1 to R5, except that when filling the mesh portion of the expanded grid with the negative electrode paste, the negative electrode paste is pressed with a jig having a smooth surface so that the surface roughness of the negative electrode plate measured by the procedure described above is 0.4 mm or less (0.1 mm).

[0171] [Table 1]

[0172] The number average molecular weight Mn of the polymer compound (polyethylene glycol oleate (PEG oleate)) measured by the above-mentioned procedure was 500, and the HLB value was 8.4. 1 In the H-NMR spectrum, a peak derived from the -CH2- of the oxyethylene unit is observed in the chemical shift range of 3.2 ppm to 3.42 ppm.1 In the H-NMR spectrum, the integral value of this peak accounts for 96 to 100% of the total integral value of this peak and the integral value of the peaks of the hydrogen atoms of the -CH2- groups and / or -CH< groups bonded to the oxygen atoms bonded to the terminal groups.

[0173] From Table 1, it can be seen that adding a polymer compound to the negative electrode material does not have the effect of suppressing stratification, regardless of the surface roughness of the negative plate, and instead promotes the decomposition of the polymer compound in the positive plate, resulting in a significant decrease in cycle life. Furthermore, because the elution of the polymer compound into the electrolyte is promoted, increasing the amount of polymer compound does not improve the effect of suppressing the amount of electricity in overcharge.

[0174] 《Lead acid battery R11~R15》 Lead-acid batteries were fabricated and evaluated in the same manner as lead-acid batteries R1 to R5, except that the pull-out load ratio W2 / W1 obtained by the same method as above was set to 1.5. The results are shown in Table 2.

[0175] 《Lead acid batteries E1~E5》 Similarly, lead-acid batteries R6 to R10 were fabricated and evaluated in the same manner as lead-acid batteries R6 to R10, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 1.5. The results are shown in Table 2.

[0176] [Table 2]

[0177] Table 2 shows that even if a polymer compound is added to the negative electrode material, simply setting the pull-out load to 1.5 times the weight of the plate assembly does not prevent stratification, and it is also difficult to prevent the polymer compound from leaching into the electrolyte (R11 to R15). On the other hand, by adding a polymer compound to the negative electrode material, setting the pull-out load to 1.5 times the weight of the plate assembly, and reducing the surface roughness of the negative plate, stratification is significantly prevented, cycle life is significantly improved, and the amount of electricity during overcharge is significantly reduced (E1 to E5).

[0178] 《Lead acid battery R16~R20》 Similarly, lead-acid batteries were fabricated in the same manner as lead-acid batteries R1 to R5, except that the pull-out load ratio W2 / W1 determined by the above-mentioned method was set to 1.8, and evaluations were carried out. The results are shown in Table 3.

[0179] 《Lead acid battery E6~E12》 Similarly, lead-acid batteries were fabricated and evaluated in the same manner as lead-acid batteries R6 to R10, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 1.8 and the surface roughness was set to the values ​​shown in Table 3. The results are shown in Table 3.

[0180] [Table 3]

[0181] Table 3 shows that even if the negative electrode material contains a polymer compound and the pull load is 1.8 times the weight of the plate assembly, stratification cannot be suppressed and it is difficult to prevent the polymer compound from leaching into the electrolyte when the surface roughness of the negative plate exceeds 0.4 mm (R16-R20). On the other hand, by adding a polymer compound to the negative electrode material, setting the pull load to 1.8 times the weight of the plate assembly, and reducing the surface roughness of the negative plate, cycle life is significantly improved and the overcharge charge is significantly reduced compared to when the pull load ratio is 1.5 times (see Table 2) (E6-E10). Furthermore, it can be seen that the smaller the surface roughness of the negative plate is within the range of 0.4 mm or less, the more significantly the cycle life is improved and the overcharge charge is significantly reduced (E11, E12).

[0182] 《Lead acid battery R21~R25》 Similarly, lead-acid batteries R1 to R5 were fabricated and evaluated, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 3.5. The results are shown in Table 4.

[0183] 《Lead acid battery E13~E17》 Similarly, lead-acid batteries R6 to R10 were fabricated and evaluated in the same manner as lead-acid batteries R6 to R10, except that the pull-out load ratio W2 / W1 obtained by the method described above was set to 3.5. The results are shown in Table 4.

[0184] [Table 4]

[0185] Table 4 shows that even if the negative electrode material contains a polymer compound and the pull-out load is set to 3.5 times the weight of the plate assembly, stratification is hardly suppressed and it is difficult to suppress the elution of the polymer compound into the electrolyte when the surface roughness of the negative plate exceeds 0.4 mm (R21 to R25). On the other hand, by adding a polymer compound to the negative electrode material, setting the pull-out load to 3.5 times the weight of the plate assembly, and reducing the surface roughness of the negative plate, it is clear that the cycle life is significantly improved and the overcharge quantity of electricity is significantly reduced compared to when the pull-out load ratio is 1.8 times (see Table 3) (E13 to E17).

[0186] 《Lead acid battery R26~R30》 Similarly, lead-acid batteries R1 to R5 were fabricated and evaluated in the same manner as lead-acid batteries R1 to R5, except that the pull-out load ratio W2 / W1 determined by the above-mentioned method was set to 6.0. The results are shown in Table 5.

[0187] 《Lead acid battery E18~E24》 Similarly, lead-acid batteries were fabricated and evaluated in the same manner as lead-acid batteries R6 to R10, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 6.0 and the surface roughness was set to the values ​​shown in Table 5. The results are shown in Table 5.

[0188] [Table 5]

[0189] Table 5 shows that even when the negative electrode material contains a polymer compound and the pull load is set to 6.0 times the weight of the plate assembly, stratification is barely suppressed and it is difficult to prevent the polymer compound from leaching into the electrolyte when the surface roughness of the negative plate exceeds 0.4 mm (R26-R30). On the other hand, when the negative electrode material contains a polymer compound, the pull load is set to 6.0 times the weight of the plate assembly, and the surface roughness of the negative plate is reduced, cycle life is significantly improved and the overcharge charge is significantly reduced compared to when the pull load ratio is 1.8 times (see Table 3) (E18-E22). Furthermore, it can be seen that the cycle life is significantly improved and the overcharge charge is significantly reduced as the surface roughness of the negative plate decreases within the range of 0.4 mm or less (E23, E24).

[0190] 《Lead acid battery R31~R35》 Similarly, lead-acid batteries were fabricated in the same manner as lead-acid batteries R1 to R5, except that the pull-out load ratio W2 / W1 determined by the above-mentioned method was set to 9.0, and evaluations were carried out. The results are shown in Table 6.

[0191] 《Lead acid battery E25~E31》 Similarly, lead-acid batteries were fabricated and evaluated in the same manner as lead-acid batteries R6 to R10, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 9.0 and the surface roughness was set to the values ​​shown in Table 6. The results are shown in Table 6.

[0192] [Table 6]

[0193] Table 6 shows that even when the negative electrode material contains a polymer compound and the pull load is set to 9.0 times the weight of the plate assembly, stratification is barely suppressed and it is difficult to prevent the polymer compound from leaching into the electrolyte when the surface roughness of the negative plate exceeds 0.4 mm (R31-R35). On the other hand, when the negative electrode material contains a polymer compound, the pull load is set to 9.0 times the weight of the plate assembly, and the surface roughness of the negative plate is reduced, cycle life is significantly improved and the overcharge charge is significantly reduced compared to when the pull load ratio is 1.8 times (see Table 3) (E25-E31). Furthermore, it can be seen that the smaller the surface roughness of the negative plate is within the range of 0.4 mm or less, the more significantly the cycle life is improved and the overcharge charge is significantly reduced (E30, E31).

[0194] Furthermore, Tables 2 to 6 show that even when a polymer compound is not included in the negative electrode material, it is possible to improve the cycle life by setting the pull-out load to 1.5 times or more the weight of the electrode plate assembly and setting the surface roughness of the negative electrode plate to 0.4 mm or less, but on the other hand, the amount of overcharge electricity increases.

[0195] Furthermore, it can be seen from Tables 2 to 6 that a sufficient effect can be obtained when the content of the polymer compound in the negative electrode material is 30 ppm or more. It can also be seen that when the content of the polymer compound in the negative electrode material is 600 ppm or more, the cycle characteristics are slightly affected, but the overcharge quantity of electricity is extremely significantly suppressed.

[0196] 《Lead acid battery E32~36》 A lead-acid battery was fabricated and evaluated in the same manner as E8, except that the polymer compound was changed from PEG to the following. The results are shown in Table 7.

[0197] Polypropylene glycol: PPG (number average molecular weight Mn 2000) Polyethylene glycol dilaurate: PEG dilaurate (number average molecular weight Mn 630, HLB = 7.3) Polyethylene glycol distearate: PEG distearate (number average molecular weight Mn 490, HLB = 6.6) Polyethylene glycol dioleate: PEG dioleate (number average molecular weight Mn 880, HLB = 8.3) Polyoxyethylene sorbitan oleate: POE sorbitan oleate (number average molecular weight Mn 430, HLB = 4.3)

[0198] [Table 7]

[0199] 《Lead acid battery E37~E41》 Lead-acid batteries were fabricated and evaluated in the same manner as lead-acid batteries E32 to E36, except that the pull-out load ratio W2 / W1 determined by the method described above was set to 6.0. The results are shown in Table 8.

[0200] [Table 8]

[0201] The results in Tables 7 and 8 show that, just as in the case of using polyethylene glycol oleate (PEG oleate) as the polymer compound, when PPG or other PEG esters are used, stratification is significantly suppressed, cycle life is significantly improved, and the amount of overcharge electricity is significantly reduced by setting the pull-out load to 1.8 times the weight of the electrode plate assembly and reducing the surface roughness of the negative electrode plate. [Industrial Applicability]

[0202] The lead-acid battery according to the present invention is suitable for use in an idle-stop vehicle as an IS lead-acid battery that is charged and discharged under PSOC conditions. The lead-acid battery can also be suitably used as a starting power source for vehicles (automobiles, motorcycles, etc.) or as an industrial power storage device (for example, a power source for an electric vehicle (forklift, etc.)). These uses are merely examples, and the present invention is not limited to these uses. [Explanation of symbols]

[0203] 1:Lead acid battery 2: Positive electrode plate 2a: ears 3: Negative electrode plate 3a: ears 4: Separator 5: Negative electrode shelf 6: Positive electrode shelf 7: Negative pole 8: Through-connector 9: Positive pole 11: Plate group 12:Battery container 13: Bulkhead 14: Cell Room 15: Lid 16: Positive terminal 17: Negative terminal 18: Liquid vent plug

Claims

1. a battery comprising: an electrode plate group; an electrolyte; and a battery case that accommodates the electrode plate group and the electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate, a pull-out load when the electrode plate group is pulled out of the battery case is 1.5 times or more of the weight of the electrode plate group; The negative electrode plate has a surface roughness of 0.4 mm or less, and the negative electrode plate contains a negative electrode material; the negative electrode material includes a polymer compound, The polymer compound is oxy C ２－４ A lead-acid battery having a repeating structure of alkylene units.

2. 2. The lead acid battery according to claim 1, wherein the polymer compound comprises at least one selected from the group consisting of a hydroxy compound having the repeating structure, an etherified product of the hydroxy compound, and an esterified product of the hydroxy compound.

3. The hydroxy compound is polyC ２－４ Alkylene glycol, oxy C ２－４ A copolymer containing a repeating structure of alkylene units, and a polyol, polyC ２－４ The lead-acid battery according to claim 2 , wherein the compound is at least one selected from the group consisting of alkylene oxide adducts.

4. The oxy C ２－４ The lead acid battery according to any one of claims 1 to 3, wherein the alkylene unit is an oxypropylene unit.

5. The oxy C ２－４ The lead acid battery according to any one of claims 1 to 3, wherein the alkylene unit is an oxyethylene unit.

6. The polymer compound has one or more hydrophobic groups, The lead acid battery according to any one of claims 1 to 5, wherein at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

7. The lead-acid battery according to any one of claims 1 to 6, wherein the polymer compound is at least one selected from the group consisting of polyethylene glycol, polypropylene glycol, polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene cocoate fatty acid sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

8. The lead acid battery according to any one of claims 1 to 7, wherein the content of the polymer compound in the negative electrode material is in the range of 30 ppm to 500 ppm by mass.

9. The lead acid battery according to any one of claims 1 to 8, wherein the polymer compound includes a compound having a number average molecular weight of 10,000 or less.

10. The lead acid battery according to any one of claims 1 to 9, wherein the polymer compound includes a compound having a number average molecular weight of 500 or more.

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