Lead-acid battery

Abstract

This lead acid storage battery is provided with at least one cell that is provided with an electrode plate group and an electrolyte solution. The electrode plate group is provided with a positive electrode plate, a negative electrode plate and a separator that is interposed between the positive electrode plate and the negative electrode plate. The negative electrode plate comprises a negative electrode material. The negative electrode material contains a nonionic surfactant that has one or more hydrophobic groups and one or more hydrophilic groups. At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The content of the nonionic surfactant in the negative electrode material is 8 ppm or more on a mass basis.

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 use. Lead-acid batteries include negative and positive plates, separators (or mats), and electrolytes. Additives are sometimes added to the components of lead-acid batteries to impart various functions.

[0003] Patent Document 1 discloses a flooded lead-acid battery having a configuration in which a negative electrode plate formed by packing a negative electrode active material in a negative electrode current collector and a positive electrode plate formed by packing a positive electrode active material in a positive electrode current collector are stacked with a separator interposed therebetween, the plate group being accommodated in a battery container together with an electrolyte, in which charging is performed intermittently and high-rate discharging to a load is performed in a partially charged state, in which at least a carbonaceous conductive material and an organic compound that suppresses coarsening of the negative electrode active material due to charging and discharging are added to the negative electrode active material, and the positive electrode plate has a unit plate pack volume [cm 3 ] Total surface area of ​​positive electrode active material [m 2 ] to 3.5 to 15.6 [m 2 / cm 3 In addition, a compound selected from a cationic flocculant, a cationic surfactant, and phosphoric acid is added to the electrolyte.

[0004] Patent Document 2 proposes a lead-acid battery in which a copolymer of propylene oxide and ethylene oxide is added to the negative electrode plate and the material in combination with lignin sulfonate.

[0005] Patent Document 3 discloses an enhanced performance rechargeable electrochemical energy storage cell, comprising a container, at least one positive electrode with a positive connector, and at least one negative electrode with a negative connector, the electrodes being disposed within the container, the container containing an acidic electrolyte, and a quantity of an isolated or synthesized performance enhancing supplement incorporated into at least one component of the rechargeable electrochemical energy storage cell selected from the group consisting of the container, the at least one negative electrode, at least one separator adapted to be disposed between the at least one positive electrode and the at least one negative electrode, the acidic electrolyte, and combinations thereof, to form a treated cell. We propose an enhanced performance rechargeable electrochemical energy storage cell, where application of a potential across the positive and negative connectors of the rechargeable electrochemical energy storage cell sufficient to pass a current between the connectors enhances at least one performance of the rechargeable electrochemical energy storage cell selected from the group consisting of reduced metal migration within the treated cell, reduced gassing from the treated cell, reduced water consumption by the treated cell, increased potential during charging of the treated cell, reduced corrosion of the positive electrode of the treated cell, reduced self-discharge of the treated cell, and combinations thereof, when compared to the performance of an untreated cell.

[0006] Patent Document 4 proposes a lead-acid battery recovery agent in which a carbon nanotube aqueous dispersion in which 0.2 to 0.5 parts by mass of carbon nanotube powder is dispersed in 100 parts by mass of water is mixed with polyoxyethylene fatty acid methyl ester and a silicone emulsion. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2013 / 058058 [Patent Document 2] Japanese Patent Application Publication No. 182662 / 1983 [Patent Document 3] Special Publication No. 2016-524288 [Patent Document 4] International Publication No. 2016 / 068281 Summary of the Invention [Problem to be solved by the invention]

[0008] When the surface of the lead contained in the negative electrode material is covered with an organic additive, the reduction reaction of hydrogen ions during overcharge is less likely to occur, so the overcharge charge tends to decrease, and the loss of electrolyte can be reduced. On the other hand, when the surface of the lead is covered with an organic additive, lead sulfate generated during discharge is less likely to dissolve during charging, so the charge acceptance decreases. Therefore, it is difficult to suppress the decrease in charge acceptance while reducing the overcharge charge. [Means for solving the problem]

[0009] One aspect of the present invention is a lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate comprises a negative electrode material, The negative electrode material includes a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups, At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms; The negative electrode material has a content of the nonionic surfactant of 8 ppm or more by mass. [Brief description of the drawings]

[0010] [Figure 1] 1 is a partially cutaway exploded perspective view showing the appearance and internal structure of a lead-acid battery according to one aspect of the present invention. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Lead-acid batteries are sometimes used in a state of insufficient charge called partial state of charge (PSOC). For example, lead-acid batteries installed in idle stop-start (ISS) vehicles are used in PSOC. When lead-acid batteries are repeatedly charged and discharged in PSOC, lead sulfate tends to accumulate, and the battery life performance tends to decrease. In order to suppress the accumulation of lead sulfate, high charge acceptance is required.

[0012] In general, in a lead-acid battery, the reaction during overcharging is greatly influenced by the reduction reaction of hydrogen ions at the interface between lead and the electrolyte. When an organic additive is contained in the negative electrode material of a lead-acid battery, the organic additive adheres to the surface of the lead, which is the active material. When the surface of the lead is covered with an organic additive, the reduction reaction of hydrogen ions is difficult to occur, so the overcharge quantity of electricity tends to decrease. However, the organic additive also adheres to the surface of the lead sulfate generated during discharge, making it difficult for the lead sulfate to dissolve during charging, and the charge acceptance decreases. Therefore, there is a trade-off between suppressing the decrease in charge acceptance and reducing the overcharge quantity of electricity, and it has been difficult to achieve both in the past. Furthermore, when the organic additive is unevenly distributed in the pores of the lead, it is necessary to increase the content of the organic additive in the negative electrode material in order to ensure a sufficient effect of reducing the overcharge quantity of electricity. However, in general, increasing the content of the organic additive significantly reduces the charge acceptance.

[0013] In lead-acid batteries, sulfuric acid aqueous solution is generally used as the electrolyte, so if an organic additive (oil, polymer, organic shrinkage inhibitor, etc.) is contained in the negative electrode material, it becomes difficult to balance the elution into the electrolyte and the adsorption to lead. For example, if an organic additive with low adsorption to lead is used, it becomes easy to elute into the electrolyte, making it difficult to reduce the amount of overcharge electricity. On the other hand, if an organic additive with high adsorption to lead is used, it becomes difficult to adhere thinly to the lead surface, and the organic additive tends to be unevenly distributed in the pores of the lead.

[0014] When organic additives are unevenly distributed within the pores of the lead, the steric hindrance of the unevenly distributed organic additives inhibits the movement of ions (such as lead ions and sulfate ions). This makes it easier for charge and discharge reactions to be inhibited. If the content of the organic additives is increased in order to ensure a sufficient effect of reducing the amount of overcharge electricity, the movement of ions within the pores is further inhibited, further inhibiting the charge and discharge reactions. If the charge and discharge reactions are inhibited, the charge acceptance and discharge performance will decrease.

[0015] In view of the above, a lead-acid battery according to one aspect of the present invention includes at least one cell including an electrode plate group and an electrolyte. The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate includes a negative electrode material. The negative electrode material includes a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups. At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The content of the nonionic surfactant in the negative electrode material is 8 ppm or more by mass. In this specification, a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups, at least one of the hydrophobic groups being a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms, is sometimes referred to as a first surfactant.

[0016] In a lead-acid battery according to one aspect of the present invention, the negative electrode material contains 8 ppm or more of the first surfactant by mass. With this configuration, it is possible to reduce the amount of electricity in overcharge while ensuring high charge acceptance. By suppressing hydrogen generation during overcharge, the amount of electrolyte loss can be reduced, which is advantageous for extending the life of the lead-acid battery.

[0017] The lead-acid battery according to one aspect of the present invention can reduce the amount of overcharge electricity while ensuring high charge acceptance for the following reasons. First, the hydrophilic group of the first surfactant ensures high adsorption to lead. On the other hand, the long-chain aliphatic hydrocarbon group having 8 or more carbon atoms prevents the lead surface from being excessively covered with the first surfactant. Therefore, a wide area of ​​the lead surface is thinly and widely covered with the first surfactant. This increases the hydrogen overvoltage, making it difficult for a side reaction to occur in which hydrogen is generated during overcharge, thereby reducing the amount of overcharge electricity. Even when the negative electrode material contains a very small amount of the first surfactant, the effect of reducing the amount of overcharge electricity can be obtained. Therefore, by including the first surfactant in the negative electrode material, the first surfactant can be present in the vicinity of lead, and it is believed that the first surfactant exerts a high adsorption effect on lead. In addition, since the negative electrode material contains the first surfactant, the first surfactant is likely to be attached to the surface of lead sulfate generated during discharge, and the solubility of lead sulfate during charging tends to decrease. However, since the thickness of the coating of the first surfactant covering the surface of lead and lead sulfate is thin, the degree to which the coating of the first surfactant inhibits the dissolution of lead sulfate and the transfer of electrons when lead ions are reduced to lead during charging is reduced. In addition, since the coating of the first surfactant is thin and uneven distribution is suppressed, the steric hindrance caused by the coating of the first surfactant is reduced, and the inhibition of the movement of lead ions in the pores of the negative electrode material is reduced. Therefore, a high diffusion rate of lead ions is maintained. As a result, even when the negative electrode material contains the first surfactant, which is an organic additive, inhibition of the charge / discharge reaction can be reduced, and a decrease in charge acceptance is suppressed.

[0018] The effect of reducing the overcharge quantity of electricity is exhibited by covering the surface of lead in the negative electrode material with the first surfactant. Therefore, it is important that the first surfactant is present in the vicinity of lead in the negative electrode material, and this allows the effect of the first surfactant to be effectively exhibited. Therefore, regardless of whether the first surfactant is contained in components of the lead-acid battery other than the negative electrode material, it is important that the negative electrode material contains the first surfactant in the specific content as described above.

[0019] The HLB of the first surfactant is preferably 4 or more. In this case, the first surfactant is more likely to be adsorbed to the lead surface in the negative electrode material. In addition, the negative electrode material may contain a carbonaceous material, and when the HLB of the first surfactant is 4 or more, the adsorption of the first surfactant to the carbonaceous material is reduced, and adsorption to the lead surface is more likely to occur. Therefore, the overcharge quantity of electricity can be further reduced.

[0020] The HLB of the first surfactant is preferably 18 or less. In this case, excessive adsorption of the first surfactant to the lead surface in the negative electrode material is easily suppressed, so that uneven distribution of the first surfactant can be further reduced, thereby ensuring higher charge acceptance.

[0021] The first surfactant preferably contains a fatty acid ester of a hydroxy compound. In this case, a good balance between a low overcharge charge and high charge acceptance can be ensured. The long-chain aliphatic hydrocarbon group is derived from the fatty acid of the fatty acid ester.

[0022] In the first surfactant, at least one of the hydrophilic groups preferably contains a polyoxyethylene chain. The high hydrophilicity of the polyoxyethylene chain can further increase the adsorption to the lead surface. On the other hand, the polyoxyethylene chain makes it easy for the first surfactant to have a linear structure, and the balance between hydrophobicity and hydrophilicity can further reduce the thickness of the coating of the first surfactant on the lead surface. Therefore, it is possible to ensure higher charge acceptance while reducing the amount of electricity in overcharge.

[0023] It is also preferable that the first surfactant contains at least one selected from the group consisting of a fatty acid ester of polyethylene glycol, a fatty acid ester of a polyethylene oxide adduct of a polyol, and a fatty acid ester of a polyol, in which case a good balance between a low overcharge quantity of electricity and high charge acceptance can be ensured.

[0024] The number of carbon atoms in the long-chain aliphatic hydrocarbon group in the first surfactant is preferably 26 or less. In this case, it is possible to ensure higher adsorption of the first surfactant to the lead surface in the negative electrode material. In addition, the negative electrode material may contain a carbonaceous material, and when the number of carbon atoms in the long-chain aliphatic hydrocarbon group is 26 or less, the adsorption of the first surfactant to the carbonaceous material is reduced, and adsorption to the lead surface is more likely to occur. Therefore, the amount of electricity in overcharge can be further reduced.

[0025] In this way, the first surfactant can thinly cover the lead surface while having high adsorption to lead due to the action of the hydrophilic group and hydrophobic group of the first surfactant. Therefore, even if the content of the first surfactant in the negative electrode material is small, the overcharged electric charge can be reduced. In addition, even if the content is small, a sufficient effect of reducing the overcharged electric charge can be ensured, so that the decrease in charge acceptance can be suppressed. From the viewpoint of easily ensuring a higher charge acceptance, the content of the first surfactant in the negative electrode material is preferably 600 ppm or less by mass. From the viewpoint of ensuring a higher effect of reducing the overcharged electric charge, the content of the first surfactant in the negative electrode material is preferably 50 ppm or more.

[0026] In this specification, the content of the first surfactant in the negative electrode material is determined for a negative electrode plate taken out from a fully charged lead-acid battery.

[0027] In the lead-acid battery, the origin of the first surfactant contained in the negative electrode material is not particularly limited as long as the first surfactant can be contained in a predetermined content in the negative electrode material. The first surfactant may be contained in any of the components of the lead-acid battery (e.g., the negative electrode plate, the positive electrode plate, the electrolyte, and the separator) when the lead-acid battery is produced. The first surfactant may be contained in one component, or in two or more components (e.g., the negative electrode plate and the electrolyte).

[0028] The negative electrode material preferably contains a condensate of a bisarene compound. The condensate of a bisarene compound corresponds to an organic shrinkage inhibitor. When the negative electrode material contains an organic shrinkage inhibitor, high discharge performance is easily obtained. The condensate of a bisarene compound is generally classified as a synthetic organic shrinkage inhibitor. When the negative electrode material contains a condensate of a bisarene compound, the specific surface area of ​​the negative electrode material increases, so that the overcharged amount of electricity tends to increase. However, even in such a case, the overcharged amount of electricity can be kept low by the action of the first surfactant. In addition, by using the condensate of a bisarene compound, the uneven distribution of the organic shrinkage inhibitor on the surface of the lead is reduced compared to the case of using a lignin compound, so that a higher charge acceptance is easily obtained. In addition, when the condensate of a bisarene compound is used, even when the lead-acid battery is charged and discharged at high temperatures, the deterioration of the negative plate is suppressed, and high discharge performance can be ensured.

[0029] The lead acid battery may be either a valve regulated (sealed) lead acid battery (VRLA type lead acid battery) or a flooded (vented) lead acid battery.

[0030] (Terminology explanation) (electrode material) The negative electrode material and the positive electrode material of the positive plate are usually held by a current collector. The electrode material is the portion of the plate excluding the current collector. A member such as a mat or pasting paper may be attached to the plate. Such a member (also called an attachment member) is included in the plate because it is used integrally with the plate. When the plate includes an attachment member (such as a mat or pasting paper), the electrode material is the portion of the plate excluding the current collector and the attachment member.

[0031] Among the positive plate, the clad type positive plate includes a plurality of porous tubes, a core metal (spine) inserted into each tube, a current collector connecting the plurality of core metals (spine), a positive electrode material filled in the tube into which the core metal (spine) is inserted, and a linking seat (spine protector) connecting the plurality of tubes. In the clad type positive plate, the positive electrode material is the portion of the plate excluding the tube, the core metal (spine), the current collector, and the linking seat (spine protector). In the clad type positive plate, the core metal (spine) and the current collector are sometimes collectively referred to as the positive electrode current collector.

[0032] (Hydrophobic and Hydrophilic Groups of the First Surfactant) The first surfactant is a nonionic surfactant. Therefore, the hydrophilic group of the first surfactant is a hydrophilic group that does not dissociate into ions in an aqueous solution of the first surfactant. Such hydrophilic groups include, for example, hydroxy groups (such as alcoholic hydroxy groups) and polyether chains. The hydrophobic group of the first surfactant is a functional group that is more hydrophobic than the hydrophilic group. At least one of the hydrophobic groups of the first surfactant may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms.

[0033] (HLB) HLB is an abbreviation for Hydrophile Lipophile Balance, and is a value that indicates the balance between hydrophobicity and hydrophilicity of a surfactant (mainly a nonionic surfactant). The HLB value of a polymer compound (P) is determined by the Griffin method.

[0034] (Organic shrink-proofing agent) The organic shrinkage inhibitor is an organic compound that inhibits the shrinkage of lead, which is the negative electrode active material, when a lead-acid battery is repeatedly charged and discharged. Organic shrinkage inhibitors often contain sulfur element.

[0035] (Sulfur content in organic shrink-proofing agent) The content of sulfur element in an organic shrink-preventer being X μmol / g means that the content of sulfur element contained in 1 g of the organic shrink-preventer is X μmol.

[0036] (Condensation product of bisarene compound) The condensation product of a bisarene compound is a condensation product containing a unit of a bisarene compound. The unit of a bisarene compound refers to a unit derived from a bisarene compound incorporated in the condensation product. A bisarene compound is a compound in which two parts each having an aromatic ring are linked via a single bond or a linking group.

[0037] (number average molecular weight) In the present specification, the number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used in determining Mn is polyethylene glycol.

[0038] (Weight average molecular weight) In this specification, the weight average molecular weight (Mw) is determined by GPC. The standard substance used in determining Mw is sodium polystyrene sulfonate.

[0039] (fully charged) The fully charged state of a flooded lead-acid battery is defined by JIS D 5301:2019. More specifically, the fully charged state is defined as a state in which the lead-acid battery is charged at a current (A) that is 0.2 times the value (unit: Ah) listed as the rated capacity until the terminal voltage (V) during charging measured every 15 minutes or the electrolyte density converted to a temperature of 20°C shows a constant value with three significant digits three consecutive times in a water tank at 25°C ± 2°C. In addition, in the case of a valve-regulated lead-acid battery, the fully charged state is defined as a state in which constant-current constant-voltage charging of 2.23 V / cell is performed in an air tank at 25°C ± 2°C at a current (A) that is 0.2 times the value (unit: Ah) listed as the rated capacity, and charging is terminated when the charging current during constant-voltage charging becomes 0.005 times the value (unit: Ah) listed as the rated capacity.

[0040] A fully charged lead-acid battery refers to a lead-acid battery that has already been chemically prepared and is fully charged. A lead-acid battery may be fully charged immediately after chemical preparation, or after a certain amount of time has passed since chemical preparation (for example, a lead-acid battery that is in use (preferably in the early stages of use) after chemical preparation may be fully charged). An early stage battery refers to a battery that has not been in use for very long and has hardly deteriorated at all.

[0041] (Top and bottom directions of lead-acid batteries or components of lead-acid batteries) In this specification, the up-down direction of a lead-acid battery or components of the lead-acid battery (such as plates, a battery case, and a separator) refers to the up-down direction in the vertical direction of the lead-acid battery when the lead-acid battery is in use. Each of the positive and negative plates has a lug for connecting to an external terminal. In some cases, such as a horizontal valve-regulated lead-acid battery, the lug is provided on the side of the plate so as to protrude laterally, but in most lead-acid batteries, the lug is usually provided on the top of the plate so as to protrude upward.

[0042] Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described in detail with respect to each of its main components, but the present invention is not limited to the following embodiment.

[0043] [Lead acid battery] (Negative plate) The negative electrode plate usually includes a negative electrode current collector in addition to a negative electrode material.

[0044] (Negative electrode current collector) The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding and punching. It is preferable to use a lattice-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

[0045] The lead alloy used for the negative electrode current collector may be any of Pb-Sb alloy, Pb-Ca alloy, and Pb-Ca-Sn alloy. These lead or lead alloys may further contain at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, etc. as an additive element. The negative electrode current collector may have a surface layer. The surface layer and the inner layer of the negative electrode current collector may have different compositions. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on the ear of the negative electrode current collector. The surface layer of the ear may contain Sn or an Sn alloy.

[0046] (Negative electrode material) The negative electrode material includes a first surfactant. The negative electrode material further includes a negative electrode active material (specifically, lead or lead sulfate) that exhibits capacity through an oxidation-reduction reaction. The negative electrode material may include at least one selected from the group consisting of an organic shrinkage inhibitor, a carbonaceous material, and other additives. Examples of the additives include barium sulfate, fibers (such as resin fibers), and a surfactant other than the first surfactant (sometimes referred to as a second surfactant). However, the additives are not limited to these. The negative electrode active material in a charged state is sponge lead, but an unformed negative plate is usually made using lead powder.

[0047] (First Surfactant) As described above, examples of the hydrophilic group possessed by the first surfactant include a hydroxy group and a polyether chain. Examples of the polyether chain include polyoxy C2-4 Alkylene chains include polyoxy C 2-4 The alkylene chain is oxyC 2-4 A polyether chain is a repeating alkylene unit. 2-4 may contain an alkylene unit, 2-4 It may contain an alkylene unit. 2-4 Examples of the alkylene unit include an oxyethylene unit, an oxypropylene unit, an oxytrimethylene unit, an oxybutylene unit, etc. From the viewpoint of high hydrophilicity and easy achievement of high adsorption to lead, the hydrophilic group preferably contains an oxyethylene unit, and more preferably contains a polyoxyethylene chain.

[0048] The first surfactant may have at least one hydrophilic group, and may have two or more hydrophilic groups. From the viewpoint of easily obtaining high adsorption ability to lead, the first surfactant preferably contains at least a polyether chain. In particular, the first surfactant preferably contains polyoxy C as the polyether chain. 2-4 When the surfactant contains an alkylene chain, it is easy to have a linear structure. Therefore, the thickness of the coating of the first surfactant formed on the surface of the lead can be reduced while ensuring high adsorption to lead. The first surfactant may have at least one polyether chain and at least one hydroxyl group. The hydroxyl group may be located at the terminal of the first surfactant. The upper limit of the number of hydrophilic groups of the first surfactant is not particularly limited, and may be, for example, 6 or less (or 4 or less).

[0049] The number of hydrophilic groups in the first surfactant may be from 1 to 6 (or from 4 to 8), or from 2 to 6 (or from 4 to 8).

[0050] 1 Polyoxy C 2-4 In the alkylene chain, oxy C 2-4 The number of repeating alkylene units is, for example, 2 or more, and may be 5 or more. 2-4 In the alkylene chain, oxy C2-4 The number of repeating alkylene units is, for example, 300 or less, optionally 200 or less, optionally 50 or less, or optionally 20 or less, or optionally 10 or less.

[0051] 1 Polyoxy C 2-4 In the alkylene chain, oxy C 2-4 The number of repeating alkylene units may be 2 or more (or 5 or more) and 300 or less, 2 or more (or 5 or more) and 200 or less, 2 or more (or 5 or more) and 50 or less, 2 or more (or 5 or more) and 20 or less, or 2 or more (or 5 or more) and 10 or less.

[0052] At least one of the hydrophobic groups of the first surfactant is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The long-chain aliphatic hydrocarbon group having 8 or more carbon atoms of the first surfactant may be referred to as the first hydrophobic group. The first surfactant may have one or more hydrophobic groups (also referred to as the second hydrophobic group) other than the first hydrophobic group. The upper limit of the number of the first hydrophobic groups in the first surfactant is not particularly limited, and may be, for example, 4 or less (or 3 or less), or 2 or less. The number of the second hydrophobic groups is not particularly limited, and may be, for example, 4 or less (or 3 or less), or 2 or less.

[0053] When the first surfactant has two or more first hydrophobic groups, the types of at least two of the first hydrophobic groups may be the same, or all of the first hydrophobic groups may be different.When the first surfactant has two or more second hydrophobic groups, the types of at least two of the second hydrophobic groups may be the same, or all of the second hydrophobic groups may be different.

[0054] The first hydrophobic group may be a saturated hydrocarbon group or an unsaturated hydrocarbon group. The first hydrophobic group may be either linear or branched. Examples of the first hydrophobic group include an alkyl group and an alkenyl group. The first hydrophobic group may be a dienyl group having two carbon-carbon double bonds, a trienyl group having three carbon-carbon double bonds, or the like. From the viewpoint of making it easier to reduce the thickness of the coating of the first surfactant formed on the lead surface, the first hydrophobic group is preferably an alkyl group or an alkenyl group.

[0055] The number of carbon atoms in the first hydrophobic group may be 8 or more. From the viewpoint of easily reducing the thickness of the coating of the first surfactant formed on the lead surface, the number of carbon atoms in the first hydrophobic group is preferably 10 or more, more preferably 11 or more, and may be 14 or more, 16 or more, or may be 17 or more. The number of carbon atoms in the first hydrophobic group is, for example, 30 or less. From the viewpoint of easily ensuring high adsorption of the first surfactant to the lead surface by a balance with the hydrophilic group, the number of carbon atoms in the first hydrophobic group is preferably 26 or less, more preferably 24 or less, or 22 or less.

[0056] The number of carbon atoms in the first hydrophobic group may be 8 to 30 (or 26 or less), 10 to 30 (or 26 or less), 11 to 30 (or 26 or less), 14 to 30 (or 26 or less), 16 to 30 (or 26 or less), 17 to 30 (or 26 or less), 8 to 24 (or 22 or less), 10 to 24 (or 22 or less), 11 to 24 (or 22 or less), 14 to 24 (or 22 or less), 16 to 24 (or 22 or less), or 17 to 24 (or 22 or less).

[0057] Specific examples of alkyl groups include 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, i-decyl, undecyl, lauryl, tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl, icosyl, henicosyl, and behenyl.Specific examples of alkenyl groups include cis-9-heptadecen-1-yl, palmitoleyl, and oleyl.

[0058] Examples of the second hydrophobic group include a hydrocarbon group. The hydrocarbon group also includes a hydrocarbon group having a substituent (e.g., a hydroxy group, an alkoxy group, and / or a carboxy group). The hydrocarbon group may be any of aliphatic, alicyclic, and aromatic. The aliphatic hydrocarbon group may have at least one selected from the group consisting of an aromatic hydrocarbon group (e.g., a phenyl group, a tolyl group, a naphthyl group) and an alicyclic hydrocarbon group (e.g., a cyclopentyl group, a cyclohexyl group) as a substituent. Examples of the aliphatic hydrocarbon group having such a substituent include a benzyl group, a phenethyl group, and a cyclohexylmethyl group. The number of carbon atoms of the aromatic hydrocarbon group and the alicyclic hydrocarbon group as the substituent is, for example, 5 or more and 20 or less, and may be 6 or more and 12 or less. The aromatic hydrocarbon group and the alicyclic hydrocarbon group may have an aliphatic hydrocarbon group (e.g., an alkyl group, an alkenyl group, an alkynyl group) as a substituent. The aliphatic hydrocarbon group as a substituent may have 1 to 30 carbon atoms, 1 to 20 or 1 to 10 carbon atoms, or 1 to 6 or 1 to 4 carbon atoms, for example.

[0059] Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 24 or less carbon atoms (e.g., 6 to 24). The number of carbon atoms in the aromatic hydrocarbon group may be 20 or less (e.g., 6 to 20), 14 or less (e.g., 6 to 14), or 12 or less (e.g., 6 to 12). Examples of the aromatic hydrocarbon group include aryl groups and bisaryl groups. Examples of the aryl group include phenyl groups and naphthyl groups. Examples of the bisaryl group 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.

[0060] Examples of the alicyclic hydrocarbon group include alicyclic hydrocarbon groups having 16 or less carbon atoms. The alicyclic hydrocarbon group may be a cross-linked 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.

[0061] The alicyclic hydrocarbon group may have 5 (or 6) or more and 16 (or less), 5 (or 6) or more and 10 (or less), or 5 (or 6) or more and 8 (or less) carbon atoms.

[0062] Examples of alicyclic hydrocarbon groups include cycloalkyl groups (cyclopentyl, cyclohexyl, cyclooctyl, etc.) and cycloalkenyl groups (cyclohexenyl, cyclooctenyl, etc.). Alicyclic hydrocarbon groups also include hydrogenated products of the above aromatic hydrocarbon groups.

[0063] From the viewpoint of facilitating thin adhesion of the first surfactant to the lead surface, among the hydrocarbon groups, an aliphatic hydrocarbon group is preferred. Examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, and a dienyl group. The aliphatic hydrocarbon group may be either linear or branched.

[0064] The number of carbon atoms in the aliphatic hydrocarbon group is less than 8, and may be 7 or less, or 6 or less. The lower limit of the number of carbon atoms depends on the type of the aliphatic hydrocarbon group; for alkyl groups, it is 1 or more, for alkenyl groups and alkynyl groups, it is 2 or more, and for dienyl groups, it is 3 or more. As the second hydrophobic group, alkyl groups and alkenyl groups are preferred.

[0065] 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, and n-hexyl.Specific examples of alkenyl groups include vinyl, 1-propenyl, and allyl.

[0066] The first surfactant may be, for example, either an ester type (including an ester ether type) or an ether type nonionic surfactant.

[0067] The first surfactant is, for example, polyoxy C 2-4 Hydroxy compounds with alkylene chains (PolyC 2-4 Alkylene glycol, different oxy C 2-4 A copolymer containing an alkylene unit and having a hydroxyl group at the end, polyol polyC 2-4 Examples of the first surfactant include esters or ethers of hydroxy compounds having a polyoxyethylene chain (polyethylene glycol, polyethylene oxide adducts of polyols, etc.). Among these, esters or ethers of hydroxy compounds having a polyoxyethylene chain (polyethylene glycol, polyethylene oxide adducts of polyols, etc.) are particularly preferred. Furthermore, as the first surfactant, esters of polyols are also preferred.

[0068] The polyol may be any of aliphatic polyols, alicyclic polyols, aromatic polyols, and heterocyclic polyols. From the viewpoint of facilitating thin spreading of the first surfactant on the lead surface, non-aromatic polyols (e.g., aliphatic polyols, alicyclic polyols (e.g., polyhydroxycyclohexane, polyhydroxynorbornane)) are preferred. As the non-aromatic polyols, for example, aliphatic diols, triol or higher aliphatic polyols (e.g., glycerin, trimethylolpropane, pentaerythritol), sugars, or sugar alcohols are preferred. As the aliphatic diols, alkylene glycols having 5 or more carbon atoms can be mentioned. As the alkylene glycols, for example, C 5-14 Alkylene glycol or C 5-10 The sugar or sugar alcohol may be, for example, sucrose, erythritol, xylitol, mannitol, or sorbitol. However, the sugar or sugar alcohol may have either a chain structure or a cyclic structure. In the alkylene oxide adduct of the polyol, the alkylene oxide is the oxy C of the first surfactant. 2-4 Corresponding to an alkylene unit, at least C2-4 In order to facilitate the first surfactant to have a linear structure, the polyol may be a diol.

[0069] Ethers are compounds in which at least some of the terminal hydroxyl groups of the above hydroxyl compounds, i.e., -OH groups (composed of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom), have been etherified to -OR. 2 Groups, where R 2 is an organic group.) In the case of ether, some or all of the terminal hydroxyl groups of the hydroxyl compound may be etherified. For example, in the first surfactant, polyoxy C 2-4 One end of the alkylene chain is an -OH group and the other is an -OR group. 2 It may be a -OR group. 2 In the group, R 2 Specifically, C corresponds to the first hydrophobic group or the second hydrophobic group. For example, in polyoxyethylene lauryl ether, the polyoxyethylene chain of polyethylene glycol and the hydroxyl group at one end correspond to the hydrophilic group, and C 12 H 25 The lauryl group of the lauryl ether moiety represented by -O- (C 12 H 25 -) corresponds to the first hydrophobic group.

[0070] The ester is an ester of at least a part of the terminal hydroxyl groups of the hydroxy compound or polyol, i.e., -OH groups (-OH groups consisting of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom) which are esterified to -OC(=O)-R 3 Groups, where R 3 is an organic group.) In the ester, polyoxy C 2-4 A part of the terminal hydroxyl groups of the hydroxy compound having an alkylene chain or the polyol may be esterified, or all of the terminals may be esterified. The ester is, for example, polyoxy C of the first surfactant. 2-4 One end of the alkylene chain is an -OH group and the other end is -OC(=O)-R 3It may be a -OC(=O)-R group. 3 In the group, R 3 corresponds to the first hydrophobic group or the second hydrophobic group. The ester may be, for example, a fatty acid ester. In the fatty acid ester, each of the first hydrophobic group and the second hydrophobic group of the first surfactant is derived from the fatty acid of the fatty acid ester. For example, in the oleic acid monoester of polyethylene glycol (also called polyoxyethylene oleate), the polyoxyethylene chain of the polyethylene glycol and the hydroxyl group at one end correspond to the hydrophilic group, and the C derived from oleic acid corresponds to the hydrophilic group. 17 H 33 -C(=O)-C 17 H 33 The portion corresponds to the first hydrophobic group.

[0071] From the viewpoint of easily obtaining higher charge acceptance while suppressing the overcharge quantity of electricity to a low level, it is preferable to use at least an ester as the first surfactant. Among them, it is preferable to use at least one selected from the group consisting of fatty acid esters of hydroxy compounds having polyoxyethylene chains and fatty acid esters of polyols (glycerin, sucrose, sorbitol, etc.). Of such fatty acid esters, it is more preferable to use fatty acid esters of polyethylene glycol and fatty acid esters of polyethylene oxide adducts of polyols (glycerin, sucrose, sorbitol, etc.). It is even more preferable to use at least fatty acid esters of polyethylene glycol. The fatty acid esters of polyethylene glycol may be monoesters or diesters, or both of them may be used.

[0072] Specific examples of ethers include polyoxyethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.Specific examples of esters (the above fatty acid esters) include polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene coconut oil fatty acid sorbitan, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, coconut oil fatty acid sorbitan, sorbitan oleate, and sorbitan stearate.However, the first surfactant is not limited to these.

[0073] The negative electrode material may contain one type of first surfactant, or may contain two or more types of first surfactant.

[0074] From the viewpoint of easily reducing the amount of overcharge electricity, the HLB of the first surfactant is preferably 4 or more, and more preferably 4.3 or more. From the viewpoint of easily ensuring higher charge acceptance, the HLB of the first surfactant is preferably 18 or less, more preferably 10 or less or 9 or less, and even more preferably 8.5 or less.

[0075] The HLB of the first surfactant may be 4 or more (or 4.3 or more) and 18 or less, or 4 or more (or 4.3 or more) and 10 or less. From the viewpoint of achieving an excellent balance between charge acceptance and the amount of overcharge electricity, the HLB of the first surfactant is preferably 4 or more (or 4.3 or more) and 9 or less, or 4 or more (or 4.3 or more) and 8.5 or less.

[0076] The first surfactant may include, for example, a component having an Mn of 20,000 or less or 10,000 or less. From the viewpoint of ensuring higher charge acceptance, the first surfactant preferably includes a component having an Mn of 3,000 or less, and may include a component having an Mn of 1,500 or less or 1,000 or less. The Mn of such a component may be 300 or more, 400 or more, or 500 or more. Two or more components having different Mn may be used as the first surfactant. In other words, the first surfactant may have multiple Mn peaks in the molecular weight distribution.

[0077] The first surfactant may include a component having an Mn of 300 or more and 20,000 or less (or 10,000 or less), 300 or more and 3,000 or less (or 1,500 or less), 300 or more (or 400 or more) and 1,000 or less, 400 or more and 20,000 or less (or 10,000 or less), 400 or more and 3,000 or less (or 1,500 or less), 500 or more and 20,000 or less (or 10,000 or less), 500 or more and 3,000 or less (or 1,500 or less), or 500 or more and 1,000 or less.

[0078] The content of the first surfactant in the negative electrode material may be 8 ppm or more by mass, and may be 10 ppm or more. From the viewpoint of further enhancing the effect of reducing the overcharge electricity amount, the content of the first surfactant in the negative electrode material is preferably 30 ppm or more by mass, and more preferably 36 ppm or more by mass. The content of the first surfactant in the negative electrode material is, for example, 1000 ppm or less by mass, and may be 600 ppm or less. From the viewpoint of easily ensuring higher charge acceptance, the content of the first surfactant in the negative electrode material is preferably 500 ppm or less by mass, more preferably 400 ppm or less or 350 ppm or less, and may be 300 ppm or less.

[0079] The content of the first surfactant in the negative electrode material is, by mass, 8 ppm or more (or 10 ppm or more) and 1000 ppm or less, 8 ppm or more (or 10 ppm or more) and 600 ppm or less, 8 ppm or more (or 10 ppm or more) and 500 ppm or less, 8 ppm or more (or 10 ppm or more) and 400 ppm or less, 8 ppm or more (or 10 ppm or more) and 350 ppm or less, 8 ppm or more (or 10 ppm or more) and 300 ppm or less, pm or less, 30 ppm or more (or 36 ppm or more) but not more than 1000 ppm, 30 ppm or more (or 36 ppm or more) but not more than 600 ppm, 30 ppm or more (or 36 ppm or more) but not more than 500 ppm, 30 ppm or more (or 36 ppm or more) but not more than 400 ppm, 30 ppm or more (or 36 ppm or more) but not more than 350 ppm, or 30 ppm or more (or 36 ppm or more) but not more than 300 ppm.

[0080] (Second Surfactant) The negative electrode material may contain a second surfactant other than the first surfactant. Examples of the second surfactant include a nonionic surfactant other than the first surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. The negative electrode material may contain one type of the second surfactant, or two or more types of the second surfactant.

[0081] The ratio of the first surfactant to the total surfactants contained in the negative electrode material is preferably as high as possible, and is preferably, for example, 70 mass% or more of the total surfactants, and may be 80 mass% or more or 90 mass% or more. The ratio of the first surfactant to the total surfactants is 100 mass% or less. The negative electrode material may contain only the first surfactant as a surfactant.

[0082] (Organic shrink-proofing agent) Organic shrink-proofing agents are generally classified into lignin compounds and synthetic organic shrink-proofing agents. Synthetic organic shrink-proofing agents can also be said to be organic shrink-proofing agents other than lignin compounds. Examples of organic shrink-proofing agents contained in the negative electrode material include lignin compounds and synthetic organic shrink-proofing agents. The negative electrode material may contain one type of organic shrink-proofing agent or two or more types of organic shrink-proofing agents.

[0083] Examples of the lignin compound include lignin and lignin derivatives. Examples of the lignin derivatives include lignin sulfonic acid or salts thereof (alkali metal salts (sodium salts, etc.)).

[0084] The synthetic organic shrink-proofing agent is an organic polymer containing elemental sulfur, and generally contains multiple aromatic rings in the molecule and elemental sulfur as a sulfur-containing group. Among the sulfur-containing groups, sulfonic acid groups or sulfonyl groups, which are stable, are preferred. The sulfonic acid groups may exist in the acid form or in the salt form such as Na salt.

[0085] At least a lignin compound may be used as the organic shrinkage inhibitor. Lignin compounds tend to have low charge acceptance compared to synthetic organic shrinkage inhibitors. However, by including a first surfactant in the negative electrode material, even when a lignin compound is used as the organic shrinkage inhibitor, the decrease in charge acceptance is suppressed and high charge acceptance can be ensured.

[0086] As the organic shrink-proofing agent, it is also preferable to use a condensation product containing at least an aromatic compound unit. For example, such a condensation product may be a condensation product of an aromatic compound with an aldehyde compound (at least one selected from the group consisting of aldehydes (e.g., formaldehyde) and condensates thereof). The organic shrink-proofing agent may contain one type of aromatic compound unit, or may contain two or more types of aromatic compound units. The aromatic compound unit refers to a unit derived from an aromatic compound incorporated in the condensation product.

[0087] Examples of the aromatic rings that aromatic compounds have include benzene rings and naphthalene rings. When aromatic compounds have multiple aromatic rings, the multiple aromatic rings may be linked by direct bonds or linking groups (e.g., alkylene groups (including alkylidene groups), sulfone groups) and the like. Examples of such structures include bisarene structures (biphenyl, bisphenylalkane, bisphenylsulfone, etc.). Examples of aromatic compounds include compounds having the above aromatic rings and at least one selected from the group consisting of hydroxyl groups and amino groups. The hydroxyl group or amino group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having a hydroxyl group or amino group. The hydroxyl group also includes salts of the hydroxyl group (-OMe). The amino group also includes salts of the amino group (specifically, salts with anions). Examples of Me include alkali metals (Li, K, Na, etc.) and metals of Group 2 of the periodic table (Ca, Mg, etc.).

[0088] As the aromatic compound, a bisarene compound [bisphenol compound, hydroxybiphenyl compound, bisarene compound having an amino group (bisarylalkane compound having an amino group, bisarylsulfone compound having an amino group, biphenyl compound having an amino group, etc.), hydroxyarene compound (hydroxynaphthalene compound, phenol compound, etc.), aminoarene compound (aminonaphthalene compound, aniline compound (aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc.)), etc.] are preferable. The aromatic compound may further have a substituent. The organic shrinkage inhibitor may contain one or more of the residues of these compounds. As the bisphenol compound, bisphenol A, bisphenol S, bisphenol F, etc. are preferable. When the negative electrode material contains a condensate of a bisarene compound (such as a condensate of an aldehyde compound), it is possible to ensure higher charge acceptance while suppressing the overcharge electricity amount to a low level.

[0089] The condensate preferably contains at least a unit of an aromatic compound having a sulfur-containing group. In particular, the use of a condensate containing at least a unit of a bisphenol compound having a sulfur-containing group is advantageous in terms of ensuring higher charge acceptance. From the viewpoint of increasing the effect of reducing the amount of overcharge electricity, it is also preferable to use a condensate of an aldehyde compound with a naphthalene compound having a sulfur-containing group and at least one selected from the group consisting of a hydroxyl group and an amino group.

[0090] The sulfur-containing group may be directly bonded to an aromatic ring contained in the compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group. The sulfur-containing group is not particularly limited, and examples thereof include a sulfonyl group, a sulfonic acid group, and salts thereof.

[0091] Also, as the organic shrink-proofing agent, for example, at least one condensate containing at least one selected from the group consisting of the above-mentioned bisarene compound units and monocyclic aromatic compound units (hydroxyarene compounds and / or aminoarene compounds, etc.) may be used. The organic shrink-proofing agent may at least contain a condensate containing a bisarene compound unit and a monocyclic aromatic compound unit (particularly, a hydroxyarene compound). Such a condensate may be a condensate of a bisarene compound and a monocyclic aromatic compound with an aldehyde compound. As the hydroxyarene compound, a phenolsulfonic acid compound (such as phenolsulfonic acid or a substituted product thereof) is preferable. As the aminoarene compound, aminobenzenesulfonic acid, alkylaminobenzenesulfonic acid, etc. are preferable. As the monocyclic aromatic compound, a hydroxyarene compound is preferable.

[0092] The negative electrode material may contain, for example, an organic shrink-proofing agent (first organic shrink-proofing agent) having a sulfur element content of 2000 μmol / g or more among the above organic shrink-proofing agents. Examples of the first organic shrink-proofing agent include the above synthetic organic shrink-proofing agents (such as the above condensates).

[0093] The sulfur element content of the first organic shrinkage inhibitor may be 2000 μmol / g or more, and is preferably 3000 μmol / g or more. The upper limit of the sulfur element content of the organic shrinkage inhibitor is not particularly limited. From the viewpoint of further enhancing the effect of reducing the amount of overcharge electricity, the sulfur element content of the first organic shrinkage inhibitor is preferably 9000 μmol / g or less, and more preferably 8000 μmol / g or less.

[0094] The sulfur element content of the first organic shrink inhibitor may be, for example, 2000 μmol / g or more (or 3000 μmol / g or more) and 9000 μmol / g or less, or 2000 μmol / g or more (or 3000 μmol / g or more) and 8000 μmol / g or less.

[0095] The first organic shrinkage inhibitor includes a condensate including a unit of an aromatic compound having a sulfur-containing group, and the condensate may include at least a unit of a bisarene compound (such as a bisphenol compound) as the unit of the aromatic compound.

[0096] The weight average molecular weight (Mw) of the first organic shrink-proofing agent is preferably equal to or greater than 7000. The Mw of the first organic shrink-proofing agent is, for example, equal to or less than 100,000, and may be equal to or less than 20,000.

[0097] The negative electrode material may contain, for example, an organic shrink-proofing agent (second organic shrink-proofing agent) having a sulfur element content of less than 2000 μmol / g. The second organic shrink-proofing agent may be, among the above organic shrink-proofing agents, a lignin compound, a synthetic organic shrink-proofing agent (particularly, a lignin compound), or the like. The sulfur element content of the second organic shrink-proofing agent is preferably 1000 μmol / g or less, and may be 800 μmol / g or less. The lower limit of the sulfur element content in the second organic shrink-proofing agent is not particularly limited, and is, for example, 400 μmol / g or more.

[0098] The Mw of the second organic shrink-proofing agent is, for example, less than 7000. The Mw of the second organic shrink-proofing agent is, for example, 3000 or more.

[0099] The negative electrode material may contain a second organic shrink-proofing agent in addition to the first organic shrink-proofing agent. When the first organic shrink-proofing agent and the second organic shrink-proofing agent are used in combination, the mass ratio thereof can be selected arbitrarily.

[0100] The content of the organic shrinkage inhibitor contained in the negative electrode material is, for example, 0.005% by mass or more, and may be 0.01% by mass or more. When the content of the organic shrinkage inhibitor is in such a range, a high discharge capacity can be ensured. The content of the organic shrinkage inhibitor is, for example, 1.0% by mass or less, and may be 0.5% by mass or less. From the viewpoint of further enhancing the effect of suppressing the decrease in charge acceptance, the content of the organic shrinkage inhibitor is preferably 0.3% by mass or less, and more preferably 0.25% by mass or less.

[0101] The content of the organic shrinkage preventer in the negative electrode material may be 0.005% by mass or more (or 0.01% by mass or more) and 1.0% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) and 0.5% by mass or less, 0.005% by mass or more (or 0.01% by mass or more) and 0.3% by mass or less, or 0.005% by mass or more (or 0.01% by mass or more) and 0.25% by mass or less.

[0102] (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).

[0103] In this specification, among the carbonaceous materials, -1 More than 1350cm -1 Peaks appearing in the following range (D band) and 1550 cm -1 More than 1600cm -1 Intensity ratio I to the peak (G band) appearing in the following range D / I GA carbonaceous material having a σ of 0 or more and 0.9 or less is called graphite. Graphite may be either artificial graphite or natural graphite.

[0104] The negative electrode material may contain one type of carbonaceous material or may contain two or more types of carbonaceous materials.

[0105] Since the first surfactant also covers the surface of the carbonaceous material, the coating amount for lead and lead sulfate is also affected by the specific surface area and amount of the carbonaceous material.

[0106] The specific surface area of ​​the carbonaceous material is, for example, 0.5 (m 2 ·g -1 ) or more, and 1(m 2 ·g -1 ) or more than 20(m 2 ·g -1 ) or more. When the specific surface area is in this range, it is easy to prevent the content of the first surfactant from becoming excessively large, and it is easy to ensure high charge acceptance. The specific surface area of ​​the carbonaceous material may be 300 (m 2 ·g -1 ) or more than 400(m 2 ·g -1 ) or more. When the specific surface area is in this range, the amount of electricity for overcharging tends to be large, but even in such a case, the amount of electricity for overcharging can be reduced by combining with the first surfactant. The specific surface area of ​​the carbonaceous material may be, for example, 1500 (m 2 ·g -1 ) or less, and 1000(m 2 ·g -1 ) or less, and 800 (m 2 ·g -1 ) or less, and 200 (m 2 ·g -1 ) or less than 150(m 2 ·g -1 When the specific surface area is in this range, the effect of reducing the overcharge electricity quantity can be further increased.

[0107] The specific surface area of ​​carbonaceous materials is 0.5 (m 2 ·g -1 ) or more 1500(m2 ·g -1 ) or less (or 1000(m 2 ·g -1 ) or less), 1(m 2 ·g -1 ) or more 1500(m 2 ·g -1 ) or less (or 1000(m 2 ·g -1 ) or less), 20(m 2 ·g -1 ) or more 1500(m 2 ·g -1 ) or less (or 1000(m 2 ·g -1 ) or less), 300(m 2 ·g -1 ) or more 1500(m 2 ·g -1 ) or less (or 1000(m 2 ·g -1 ) or less), 400(m 2 ·g -1 ) or more 1500(m 2 ·g -1 ) or less (or 1000(m 2 ·g -1 ) or less), 300(m 2 ·g -1 ) or more (or 400 (m 2 ·g -1 ) or more) 800(m 2 ·g -1 ) or less, 0.5(m 2 ·g -1 ) or more 800(m 2 ·g -1 ) or less (or 200 (m 2 ·g -1 ) or less), 1(m 2 ·g -1 ) or more 800(m 2 ·g -1 ) or less (or 200 (m 2 ·g -1 ) or less), 20(m 2 ·g -1 ) or more 800(m 2 ·g -1 ) or less (or 200 (m 2 ·g -1 ) or less), 0.5(m2 ·g -1 ) or more 150(m 2 ·g -1 ) or less, 1(m 2 ·g -1 ) or more 150(m 2 ·g -1 ) or less, or 20(m 2 ·g -1 ) or more 150(m 2 ·g -1 ) or less.

[0108] The specific surface area of ​​the carbonaceous material is a BET specific surface area determined by a gas adsorption method using nitrogen gas.

[0109] The content of the carbonaceous material in the negative electrode material is, for example, 0.05 mass% or more, and may be 0.10 mass% or more.The content of the carbonaceous material is, for example, 5 mass% or less, and may be 3 mass% or less.

[0110] The content of the carbonaceous material in the negative electrode material may be 0.05% by mass to 5% by mass, 0.05% by mass to 3% by mass, 0.10% by mass to 5% by mass, or 0.10% by mass to 3% by mass.

[0111] (Barium Sulfate) The content of barium sulfate in the negative electrode material is, for example, 0.05% by mass or more, and may be 0.10% by mass or more. The content of barium sulfate in the negative electrode material is, for example, 3% by mass or less, and may be 2% by mass or less.

[0112] The content of barium sulfate in the negative electrode material may be from 0.05 to 3% by mass, from 0.05 to 2% by mass, from 0.10 to 3% by mass, or from 0.10 to 2% by mass.

[0113] (Analysis of negative electrode materials or components) The method for analyzing the negative electrode material or its constituents is described below. Before measurement or analysis, a fully charged lead-acid battery is disassembled to obtain the negative plate to be analyzed. The obtained negative plate is washed with water to remove sulfuric acid from the negative plate. The washing is continued until a pH test paper is pressed against the washed surface of the negative plate and no change in color of the test paper is confirmed. However, the washing time should be within 2 hours. The washed negative plate is dried in a reduced pressure environment at 60±5°C for about 6 hours. If the negative plate contains an adhesive material after drying, the adhesive material is removed by peeling. Next, the negative electrode material is separated from the negative plate to obtain a sample (hereinafter referred to as sample A). Sample A is crushed as necessary and subjected to analysis.

[0114] (1) Analysis of surfactants (1-1) Qualitative analysis of the first surfactant (a) OxyC 2-4 Analysis of alkylene units A ground sample A is used. 150.0±0.1 mL of chloroform is added to 100.0±0.1 g of sample A, and the mixture is stirred at 20±5° C. for 16 hours to extract the first surfactant. The solid content is then removed by filtration. The first surfactant is identified by obtaining information from at least one of an infrared spectroscopy spectrum, an ultraviolet-visible absorption spectrum, an NMR spectrum, an LC-MS, and a pyrolysis GC-MS for a chloroform solution in which the first surfactant obtained by extraction is dissolved or a first surfactant obtained by drying the chloroform solution.

[0115] From the chloroform solution in which the first surfactant is dissolved obtained by extraction, chloroform is distilled off under reduced pressure to recover the chloroform-soluble matter. The chloroform-soluble matter is dissolved in deuterated chloroform and then subjected to the following conditions: 1 1H-NMR spectrum is measured. 1 When a peak is observed in the chemical shift range of 3.2 ppm or more and 3.8 ppm or less in the H-NMR spectrum, the first surfactant is oxy-C 2-4 It is clear that the compound has an alkylene unit. The splitting state of the peaks indicates that the compound is oxy-C.2-4 The type of alkylene unit is specified.

[0116] Apparatus: AL400 nuclear magnetic resonance spectrometer manufactured by JEOL Ltd. Observation frequency: 395.88MHz Pulse width: 6.30μs Pulse repetition time: 74.1411 seconds Accumulation count: 32 Measurement temperature: room temperature (20~35℃) Standard: 7.24ppm Sample tube diameter: 5mm

[0117] In addition, in the qualitative analysis, 1 When calculating the integral value of a peak in a H-NMR spectrum, 1 In the H-NMR spectrum, two points without significant signals are determined so as to sandwich the corresponding peak, and each integral value is calculated using a straight line connecting these two points as a baseline. For example, for a peak that exists in a chemical shift range of 3.2 ppm to 3.8 ppm, a straight line connecting two points on the spectrum between 3.2 ppm and 3.8 ppm is used as the baseline. For example, for a peak that exists in a chemical shift range of more than 3.8 ppm to 4.0 ppm, a straight line connecting two points on the spectrum between 3.8 ppm and 4.0 ppm is used as the baseline.

[0118] (b) Analysis of hydrophobic groups in esters When the first surfactant is an ester, a predetermined amount of the first surfactant obtained by drying the chloroform solution in which the first surfactant obtained by extraction is dissolved in (a) is collected, and an aqueous potassium hydroxide solution is added. This causes the first surfactant to be saponified, 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 first hydrophobic group and the second hydrophobic group contained in the first surfactant. Analytical equipment: Shimadzu Corporation, high-performance general-purpose gas chromatogram GC-2014 Column: DEGS (diethylene glycol succinate) 2.1m Oven temperature: 180~120℃ Inlet temperature: 240℃ Detector temperature: 240℃ Carrier gas: He (flow rate: 50 mL / min) Injection volume: 1μL~2μL

[0119] (c) Analysis of hydrophobic groups in ethers When the first surfactant is an ether, a predetermined amount of the first surfactant obtained by drying the chloroform solution in which the first surfactant is dissolved, obtained by extraction in the above (a), is collected and hydrogen iodide is added. This converts the organic group of the ether moiety of the first surfactant (the above-mentioned R 3 ) corresponding to the iodide (R 3 I) is generated and oxy C 2-4 Diiodo C corresponding to the alkylene unit 2-4 Alkanes are produced. The hydrogen iodide mentioned above is converted to ether iodide and diiodo C. 2-4 A sufficient amount of the surfactant 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 first hydrophobic group and the second hydrophobic group contained in the first surfactant.

[0120] (1-2) Quantitative analysis of the first surfactant The appropriate amount of the chloroform soluble matter was measured with an accuracy of ±0.0001 g. r (g) Dissolve in deuterated chloroform together with tetrachloroethane (TCE), 1 Measure the H-NMR spectrum. The integral value (S a ) and the integral value of the peak due to TCE (S r ) and calculate the mass-based content C of the first surfactant in the negative electrode material from the following formula: n Calculate the ppm.

[0121] C n =S a / S r ×N r / N a ×M a / M r ×m r / m×1000000 (In the formula, M a The molecular weight of the structure that shows a peak in the chemical shift range of 3.2 to 3.8 ppm (more specifically, oxy C 2-4 (the molecular weight of the repeating structure of alkylene units) and N a is the number of hydrogen atoms attached to the carbon atoms in the main chain of the repeating unit. r、 M r are the number of hydrogen atoms contained in the molecule of the reference material, the molecular weight of the reference material, and m (g) is the mass of the negative electrode material used for extraction.) In addition, the standard substance in this analysis is TCE, so N r =2, M r = 168. Also, m = 100.

[0122] For example, when the first surfactant contains a polyoxyethylene chain, M a is 44, and N a is 4. Polyoxy C 2-4 Oxy C with two or more alkylene chains 2-4 When the alkylene unit is present, N a and M.a are each oxy C 2-4 Alkylene unit N a Value and M a Repeat the value for each oxy C in the structure 2-4 This is an average value obtained by using the molar ratio (mol %) of alkylene units.

[0123] In addition, in the 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.

[0124] (1-3) Mn measurement of the first surfactant Using the above chloroform solubles, the first surfactant is subjected to GPC measurement using the following apparatus under the following conditions. A calibration curve (calibration curve) is separately created from a plot of Mn of the standard substance versus elution time. The Mn of the first surfactant is calculated based on this calibration curve and the GPC measurement results of the first surfactant. However, the first surfactant may be in a decomposed state in the chloroform solubles.

[0125] Analysis system: 20A system (Shimadzu Corporation) Column: Two GPC KF-805L (Shodex) columns connected in series Column temperature: 30℃±1℃ 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)

[0126] (2) Analysis of organic shrinkage inhibitors (2-1) Qualitative analysis of organic shrinkage inhibitors in negative electrode materials The crushed sample A is immersed in a 1 mol / L aqueous solution of sodium hydroxide to extract the organic shrink-preventing agent. Next, the first organic shrink-preventing agent and the second organic shrink-preventing agent are separated from the extract as necessary. For each of the separated products containing each organic shrink-preventing agent, insoluble components are removed by filtration, and the resulting solution is desalted, concentrated, and dried. Desalting is performed using a desalting column, or by passing the solution through an ion exchange membrane, or by placing the solution in a dialysis tube and immersing it in distilled water. This is dried to obtain a powder sample of the organic shrink-preventing agent (hereinafter referred to as sample B).

[0127] The type of organic shrink-proofing agent is identified by combining information obtained from the following: infrared spectrum measured using sample B of the organic shrink-proofing agent obtained in this manner; ultraviolet-visible absorption spectrum measured using an ultraviolet-visible spectrometer after diluting sample B with distilled water or the like; 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, which can provide information on the individual compounds that make up the substance.

[0128] The first and second organic shrink-preventing agents are separated from the extract as follows. First, the extract is measured by infrared spectroscopy, NMR, and / or GC-MS to determine whether it contains multiple organic shrink-preventing agents. Next, the extract is analyzed by GPC to measure the molecular weight distribution. If the multiple organic shrink-preventing agents can be separated by molecular weight, the organic shrink-preventing agents are separated by column chromatography based on the difference in molecular weight. If separation based on the difference in molecular weight is difficult, one of the organic shrink-preventing agents is separated by precipitation separation using the difference in solubility that differs depending on the type and / or amount of functional groups that the organic shrink-preventing agents have. Specifically, the extract is dissolved in an aqueous NaOH solution, and an aqueous sulfuric acid solution is dropped into the mixture to adjust the pH of the mixture, thereby flocculating and separating one of the organic shrink-preventing agents. The separated product is dissolved again in an aqueous NaOH solution, and the insoluble components are removed by filtration as described above from the mixture obtained. The remaining solution after separating one of the organic shrink-preventing agents is concentrated. The resulting concentrate contains the other organic shrinkage inhibitor, and the insoluble components are removed from the concentrate by filtration as described above.

[0129] (2-2) Quantitative determination of organic shrinkage inhibitor content in negative electrode material As in the above (2-1), a solution is obtained by removing insoluble components from each of the separated products containing the organic shrinkage inhibitor by filtration. 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 calibration curve prepared in advance.

[0130] In addition, when a lead-acid battery with an unknown content of organic shrink-proofing agent is obtained and the content of the organic shrink-proofing agent is measured, the structural formula of the organic shrink-proofing agent cannot be precisely specified, so the same organic shrink-proofing agent cannot be used for the calibration curve. In this case, a calibration curve is created using the organic shrink-proofing agent extracted from the negative electrode of the battery and a separately available organic polymer that shows similar shapes in the ultraviolet-visible absorption spectrum, infrared spectroscopy spectrum, and NMR spectrum, and the content of the organic shrink-proofing agent is measured using the ultraviolet-visible absorption spectrum.

[0131] (2-3) Sulfur content in organic shrinkage inhibitors As in (2-1) above, after obtaining sample B of the organic shrink-proofing agent, the sulfur element in 0.1 g of the organic shrink-proofing agent is converted to sulfuric acid by the oxygen combustion flask method. At this time, sample B is burned in a flask containing an adsorption solution to obtain an eluate in which sulfate ions are dissolved in the adsorption solution. Next, the sulfur element content (c1) in 0.1 g of the organic shrink-proofing agent is obtained by titrating the eluate with barium perchlorate using thorin as an indicator. Next, c1 is multiplied by 10 to calculate the sulfur element content (μmol / g) in the organic shrink-proofing agent per 1 g.

[0132] (2-4) Mw measurement of organic shrinkage regulators As in (2-1) above, after obtaining sample B of the organic shrink-preventing agent, the GPC measurement of the organic shrink-preventing agent is carried out using the following apparatus under the following conditions. Separately, a calibration curve (calibration curve) is created from a plot of the Mw of the standard substance versus elution time. Based on this calibration curve and the GPC measurement results of the organic shrink-preventing agent, the Mw of the organic shrink-preventing agent is calculated.

[0133] GPC equipment: Build-up GPC system SD-8022 / DP-8020 / AS-8020 / CO-8020 / UV-8020 (Tosoh Corporation) Column: TSKgel G4000SWXL, G2000SWXL (7.8 mm I.D. x 30 cm) (Tosoh Corporation) Detector: UV detector, λ=210nm Eluent: A mixture of 1 mol / L NaCl aqueous solution: acetonitrile (volume ratio = 7:3) Flow rate: 1mL / min. Concentration: 10mg / mL Injection volume: 10μL Standard substance: Sodium polystyrene sulfonate (Mw=275,000, 35,000, 12,500, 7,500, 5,200, 1,680)

[0134] (3) Analysis of carbonaceous materials (3-1) Separation and quantification of carbonaceous materials The crushed sample A is used. 30 mL of nitric acid solution with a concentration of 60% by mass is added per 5 g of sample A, and heated at 70°C ± 5°C. Furthermore, 10 g of disodium ethylenediaminetetraacetate, 30 mL of ammonia water with a concentration of 28% by mass, and 100 mL of water are added per 5 g of sample A, and heating is continued to dissolve the soluble matter. The sample thus pretreated is collected by filtration. The collected sample is passed through a sieve with 500 μm openings to remove large components such as reinforcing materials, and the components that pass through the sieve are collected as carbonaceous materials.

[0135] The content of the carbonaceous material in the negative electrode material is determined by measuring the mass of the carbonaceous materials separated by the above procedure and calculating the ratio (mass %) of the total mass of the pulverized sample.

[0136] (3-2) BET specific surface area of ​​carbonaceous materials The BET specific surface area of ​​the carbonaceous material is determined by the gas adsorption method using the carbonaceous material separated by the above procedure (3-1) using the BET equation. The carbonaceous material is pretreated by heating at 150°C for 1 hour in a nitrogen flow to remove moisture. The BET specific surface area of ​​the pretreated carbonaceous material is determined using the following apparatus under the following conditions. Measurement equipment: Micromeritics TriStar3000 Adsorption gas: Nitrogen gas with a purity of 99.99% or higher Adsorption temperature: liquid nitrogen boiling point (77K) Calculation method for BET specific surface area: Complies with 7.2 of JIS Z 8830:2013

[0137] (4) Determination of barium sulfate Add 50 ml of 20% by mass nitric acid to 10 g of crushed sample A, heat for about 20 minutes, and dissolve the lead components as lead ions. Filter the resulting solution to separate out solids such as carbonaceous materials and barium sulfate.

[0138] The obtained solid content is dispersed in water to obtain a dispersion, and then components other than the carbonaceous material and barium sulfate (e.g., reinforcing material) are removed from the dispersion using a sieve. Next, the dispersion is subjected to suction filtration using a membrane filter whose mass has been measured in advance, and the membrane filter together with the filtered sample is dried in a dryer at 110°C ± 5°C. The filtered sample is a mixed sample of the carbonaceous material and barium sulfate. The mass of the membrane filter is subtracted from the total mass of the dried mixed sample (hereinafter referred to as sample C) and the membrane filter to obtain the mass of sample C (M m ) is measured. 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 obtain the mass of barium sulfate (M B ) is required.

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

[0140] The formation can be carried out by immersing the plate group including the unformed negative plate in an electrolyte containing sulfuric acid in a lead-acid battery container and charging the plate group. However, the formation may be carried out before assembling the lead-acid battery or the plate group. The formation produces spongy lead.

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

[0142] The positive electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding and punching. It is preferable to use a lattice-shaped current collector as the positive electrode current collector because it is easy to support the positive electrode material.

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

[0144] The positive electrode material contained in the positive electrode plate contains a positive electrode active material (lead dioxide or lead sulfate) that develops capacity through an oxidation-reduction reaction. The positive electrode material may contain other additives as necessary.

[0145] Unformed paste-type positive plates are obtained by filling a positive current collector with a positive paste, aging it, and drying it. The positive paste is prepared by kneading lead powder, additives, water, and sulfuric acid. Unformed clad-type positive plates are formed by filling a porous tube with lead powder or lead powder in a slurry form, into which a core metal (spine) connected by a current collector is inserted, and connecting multiple tubes with a spine protector. Then, these unformed positive plates are formed to obtain positive plates.

[0146] The formation can be carried out by immersing an electrode plate group including unformed positive plates in an electrolyte solution containing sulfuric acid in a battery container of a lead-acid battery and charging the electrode plate group, although the formation may also be carried out before assembling the lead-acid battery or the electrode plate group.

[0147] (Separator) A separator may be disposed between the negative electrode plate and the positive electrode plate, and may be made of at least one material selected from a nonwoven fabric and a microporous membrane.

[0148] A nonwoven fabric is a mat in which fibers are intertwined without being woven, and is mainly composed of fibers. For example, 60% or more by mass of the nonwoven fabric is made of fibers. As the fibers, glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers (polyethylene terephthalate fibers, etc.), pulp fibers, etc. can be used. Among them, glass fibers are preferable. The nonwoven fabric may contain components other than fibers (for example, acid-resistant inorganic powder, polymers as binders), etc.

[0149] On the other hand, a microporous membrane is a porous sheet mainly composed of components other than fiber components, and can be obtained, for example, by extruding a composition containing a pore-forming agent into a sheet, and then removing the pore-forming agent to form pores. The microporous membrane is preferably made of an acid-resistant material, and a microporous membrane mainly composed of a polymer component is preferred. The polymer component is preferably polyolefin (polyethylene, polypropylene, etc.). The pore-forming agent can be at least one selected from the group consisting of polymer powder and oil.

[0150] The separator may be, for example, composed of only a nonwoven fabric or only a microporous membrane. Furthermore, the separator may be, as necessary, 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 projections interlocked.

[0151] The separator may be in a sheet shape or may be formed in a bag shape. A sheet-shaped separator may be sandwiched between the positive electrode plate and the negative electrode plate. Also, the electrode plate may be sandwiched between a folded sheet-shaped separator. In this case, the positive electrode plate sandwiched between the folded sheet-shaped separator and the negative electrode plate sandwiched between the folded sheet-shaped separator may be stacked, or one of the positive electrode plate and the negative electrode plate may be sandwiched between the folded sheet-shaped separator and stacked with the other electrode plate. Also, the sheet-shaped separator may be folded into a bellows shape, and the positive electrode plate and the negative electrode plate may be sandwiched between the bellows-shaped separator 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 along the horizontal direction of the lead-acid battery (for example, so that the folded portion is parallel to the horizontal direction) or along the vertical direction (for example, 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. Since the upper portions of the positive and negative plates usually have lugs, when the separator is arranged so that the folded portion is along the horizontal direction of the lead-acid battery, the positive and negative plates are arranged only in the recesses on one main surface side of the separator (that is, a double separator is interposed between the 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 layer of 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 or negative electrode plate.

[0152] (electrolyte) The electrolyte is an aqueous solution containing sulfuric acid, which may be gelled as necessary. The electrolyte may contain the first surfactant.

[0153] 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 necessary. Examples of metal cations include at least one selected from the group consisting of Na ions, Li ions, Mg ions, and Al ions.

[0154] 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.

[0155] 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.

[0156] (others) The lead-acid battery can be obtained by a manufacturing method including a step of housing a plate group and an electrolyte in a cell chamber of a battery case. Each cell of the lead-acid battery includes a plate group and an electrolyte housed in each cell chamber. The plate group is assembled by stacking a positive electrode plate, a negative electrode plate, and a separator such that the separator is interposed between the positive electrode plate and the negative electrode plate before housing in the cell chamber. The positive electrode plate, the negative electrode plate, the electrolyte, and the separator are each prepared before assembling the plate group. The manufacturing method of the lead-acid battery may include a step of chemically forming at least one of the positive electrode plate and the negative electrode plate, as necessary, after the step of housing the plate group and the electrolyte in the cell chamber.

[0157] Each plate in the plate group may be one or more. When the plate group includes two or more negative plates, if at least one negative plate satisfies the condition that the negative electrode material contains the first surfactant in the above content, the effect of suppressing the decrease in charge acceptance of this negative plate is obtained, and the effect of reducing the overcharge electricity amount is obtained according to the number of such negative plates. From the viewpoint of further suppressing the decrease in charge acceptance and ensuring a high effect of reducing the overcharge electricity amount, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of negative plates included in the plate group satisfy the above condition. The ratio of negative plates that satisfy the above condition among the negative plates included in the plate group is 100% or less. All of the negative plates included in the plate group may satisfy the above condition.

[0158] When the lead-acid battery has two or more cells, it is sufficient that the plate groups of at least some of the cells have negative plates that satisfy the above conditions. From the viewpoint of further suppressing the decrease in charge acceptance and ensuring a high effect of reducing the overcharged amount of electricity, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of cells included in the lead-acid battery have plate groups including negative plates that satisfy the above conditions. The ratio of cells included in the lead-acid battery that have plate groups including negative plates that satisfy the above conditions is 100% or less. It is preferable that all of the plate groups included in the lead-acid battery have negative plates that satisfy the above conditions.

[0159] FIG. 1 shows an 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 a plurality of cell chambers 14 by partition walls 13. Each cell chamber 14 contains one plate group 11. The opening of the battery case 12 is closed by a lid 15 that has a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a vent plug 18 for each cell chamber. When refilling with water, the vent plug 18 is removed and refilling liquid is added. The vent plug 18 may have a function of discharging gas generated in the cell chamber 14 to the outside of the battery.

[0160] Each electrode plate group 11 is formed by stacking a plurality of negative electrode plates 2 and positive electrode plates 3 with a separator 4 interposed therebetween. Here, a pouch-shaped separator 4 that accommodates the negative electrode plates 2 is shown, but the shape of the separator is not particularly limited. In a cell chamber 14 located at one end of the battery case 12, a negative electrode shelf portion 6 that connects a plurality of negative electrode plates 2 in parallel is connected to a through connector 8, and a positive electrode shelf portion 5 that connects a plurality of positive electrode plates 3 in parallel is connected to a positive electrode column 7. The positive electrode column 7 is connected to a positive electrode terminal 17 outside the lid 15. In a cell chamber 14 located at the other end of the battery case 12, a negative electrode column 9 is connected to the negative electrode shelf portion 6, and a through connector 8 is connected to the positive electrode shelf portion 5. The negative electrode column 9 is connected to a negative electrode terminal 16 outside the lid 15. Each through connector 8 passes through a through hole provided in the partition wall 13 to connect the electrode plate groups 11 of adjacent cell chambers 14 in series.

[0161] The positive electrode shelf 5 is formed by welding the lugs provided on the upper part of each positive electrode plate 3 together by a cast-on-strap method or a burning method. The negative electrode shelf 6 is also formed by welding the lugs provided on the upper part of each negative electrode plate 2 together in the same manner as the positive electrode shelf 5.

[0162] The lid 15 of the lead-acid battery has a single structure (single lid), but 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 a top lid). The lid having a double structure may have a reflux structure between the inner lid and the outer lid for returning the electrolyte to the inside of the battery (inside the inner lid) from a reflux port provided in the inner lid.

[0163] In this specification, the overcharge electricity quantity and the charge acceptance are evaluated according to the following procedures: The rated voltage of the test battery used in the evaluation is 2 V / cell, and the rated 5-hour rate capacity is 32 Ah.

[0164] (2) Evaluation (a) Overcharged electricity Using the above test battery in a fully charged state, the overcharged quantity of electricity is evaluated according to the following procedure. Specifically, the fully charged test battery is charged at a constant voltage of 2.4V / cell for 168 hours in a water bath at a temperature of 60±3°C. The charge current (A) during this constant voltage charge is multiplied by the charge time (h) to obtain the integrated value (Ah) of the overcharged quantity of electricity. The overcharged quantity of electricity is evaluated based on this integrated value.

[0165] (b) Charge acceptance Using a fully charged test battery, measure the amount of electricity at 10 seconds. Specifically, the test battery is discharged at 6.4A for 30 minutes and left for 16 hours. After that, the upper limit of the current is set to 200A and the test battery is charged at 2.42V / cell. Determine The battery is charged at a voltage and the accumulated quantity of electricity for 10 seconds (the quantity of electricity at the 10th second) is measured. Both operations are carried out in a water tank at 25°C ± 2°C. The accumulated quantity of electricity for 10 seconds is used as an index for evaluating the charge acceptance.

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

[0167] (1) A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate comprises a negative electrode material, the negative electrode material includes a nonionic surfactant (first surfactant) having one or more hydrophobic groups and one or more hydrophilic groups; At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms (first hydrophobic group), A lead-acid battery, wherein the content of the nonionic surfactant in the negative electrode material is 8 ppm or more by mass.

[0168] (2) In the above (1), the number of the first hydrophobic groups may be 4 or less, 3 or less, or 2 or less.

[0169] (3) In the above (1) or (2), the first hydrophobic group may have 10 or more carbon atoms, 11 or more, 14 or more, 16 or more, or 17 or more carbon atoms.

[0170] (4) In any one of the above (1) to (3), the first hydrophobic group may have 30 or less, 26 or less, 24 or less, or 22 or less carbon atoms.

[0171] (5) In any one of the above (1) to (4), the first surfactant may have one or more second hydrophobic groups other than the first hydrophobic group.

[0172] (6) In the above (5), the number of the second hydrophobic groups may be 4 or less, 3 or less, or 2 or less.

[0173] (7) In any one of the above (1) to (6), the number of the hydrophilic groups may be 6 or less, or 4 or less.

[0174] (8) In any one of the above (1) to (7), the number of the hydrophilic groups may be two or more.

[0175] (9) In any one of the above (1) to (8), the first surfactant is polyoxy C 2-4 It may contain an alkylene chain.

[0176] (10) In the above (9), one polyoxy C 2-4 In the alkylene chain, oxy C 2-4 The number of repeating alkylene units may be 2 or more, or 5 or more.

[0177] (11) In the above (9) or (10), one polyoxy C 2-4 In the alkylene chain, oxy C 2-4 The number of repeating alkylene units may be 300 or less, 200 or less, 50 or less, 20 or less, or 10 or less.

[0178] (12) In any one of the above (1) to (11), at least one of the hydrophilic groups may contain a polyoxyethylene chain.

[0179] (13) In any one of the above (1) to (12), the first surfactant contains a fatty acid ester of a hydroxy compound, The long chain aliphatic hydrocarbon group may be derived from a fatty acid of the fatty acid ester.

[0180] (14) In the above (13), the first surfactant may include at least one selected from the group consisting of a fatty acid ester of polyethylene glycol, a fatty acid ester of a polyethylene oxide adduct of a polyol, and a fatty acid ester of a polyol.

[0181] (15) In any one of the above (1) to (14), the first surfactant may include at least one selected from the group consisting of polyethylene glycol oleate, polyethylene glycol dioleate, polyethylene glycol dilaurate, polyethylene glycol distearate, polyoxyethylene sorbitan coconut oil fatty acid, polyoxyethylene sorbitan oleate, polyoxyethylene sorbitan stearate, sorbitan coconut oil fatty acid, sorbitan oleate, and sorbitan stearate.

[0182] (16) In any one of the above (1) to (15), the first surfactant may have an HLB of 4 or more, or 4.3 or more.

[0183] (17) In any one of the above (1) to (16), the first surfactant may have an HLB of 18 or less, 10 or less, 9 or less, or 8.5 or less.

[0184] (18) In any one of the above (1) to (17), the first surfactant may contain a component having an Mn of 300 or more, 400 or more, or 500 or more.

[0185] (19) In the above (18), the Mn of the component may be 20,000 or less, 10,000 or less, 3,000 or less, 1,500 or less, or 1,000 or less.

[0186] (20) In any one of the above (1) to (19), the content of the first surfactant in the negative electrode material may be, on a mass basis, 8 ppm or more, 10 ppm or more, 30 ppm or more, or 36 ppm or more.

[0187] (21) In any one of the above (1) to (20), the content of the first surfactant in the negative electrode material may be, by mass, 1000 ppm or less, 600 ppm or less, 500 ppm or less, 400 ppm or less, 350 ppm or less, or 300 ppm or less.

[0188] (22) In any one of the above (1) to (21), the negative electrode material may contain an organic shrinkage preventer.

[0189] (23) In the above (22), the organic shrink-proofer may include a first organic shrink-proofer having a sulfur element content of 2000 μmol / g or more or 3000 μmol / g or more.

[0190] (24) In the above (23), the sulfur element content of the first organic shrink-proofing agent may be 9000 μmol / g or less or 8000 μmol / g or less.

[0191] (25) In the above (23) or (24), the first organic shrink-preventing agent may have an Mw of 7,000 or more.

[0192] (26) In any one of the above (23) to (25), the first organic shrink-preventing agent may have an Mw of 100,000 or less, or 20,000 or less.

[0193] (27) In any one of the above (1) to (26), the negative electrode material (or the organic shrinkage preventer or the first organic shrinkage preventer) may contain a condensate of a bisarene compound.

[0194] (28) In any one of the above (1) to (27), the negative electrode material (or the organic shrink-preventing agent) may contain a lignin compound.

[0195] (29) In any one of the above (22) to (28), the content of the organic shrink-preventing agent in the negative electrode material may be 0.005% by mass or more, or 0.01% by mass or more.

[0196] (30) In any one of the above (22) to (29), the content of the organic shrinkage preventer in the negative electrode material may be 1.0 mass % or less, 0.5 mass % or less, 0.3 mass % or less, or 0.25 mass % or less.

[0197] (31) In any one of the above (1) to (30), the negative electrode material may contain a carbonaceous material.

[0198] (32) In the above (31), the specific surface area of ​​the carbonaceous material is 0.5 (m 2 ·g -1 ) or more, 1(m 2 ·g -1 ) or more, 20(m 2 ·g -1 ) or more, 300(m 2 ·g -1 ) or more than 400(m 2 ·g -1 ) or more.

[0199] (33) In the above (31) or (32), the specific surface area of ​​the carbonaceous material is 1500 (m 2 ·g -1 ) or less, 1000(m 2 ·g -1 ) or less, 800(m 2 ·g -1 ) or less, 200(m 2 ·g -1 ) or less, or 150(m 2 ·g -1 ) or less.

[0200] (34) In any one of the above (31) to (33), the content of the carbonaceous material in the negative electrode material may be 0.05 mass % or more, or 0.10 mass % or more.

[0201] (35) In any one of the above (31) to (34), the content of the carbonaceous material in the negative electrode material may be 5 mass % or less or 3 mass % or less.

[0202] (36) In any one of the above (1) to (35), the negative electrode material may contain barium sulfate.

[0203] (37) In the above (36), the content of the barium sulfate in the negative electrode material may be 0.05% by mass or more, or 0.10% by mass or more.

[0204] (38) In the above (36) or (37), the content of the barium sulfate in the negative electrode material may be 3 mass % or less or 2 mass % or less.

[0205] (39) In any one of the above (1) to (38), the specific gravity of the electrolyte in a fully charged lead-acid battery at 20° C. may be 1.20 or more or 1.25 or more.

[0206] (40) In any one of the above (1) to (39), the specific gravity of the electrolyte in a fully charged lead-acid battery at 20° C. may be 1.35 or less or 1.32 or less.

[0207] [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.

[0208] Lead-acid batteries E1 to E20 and C1 to C7 (1) Preparation of lead-acid batteries (a) Preparation of the negative electrode plate The raw materials lead powder, barium sulfate, carbon black, the surfactant shown in the table, and the organic shrinkage inhibitor shown in the table are mixed with an appropriate amount of sulfuric acid aqueous solution to obtain a negative electrode paste. At this time, the components are mixed so that the content of the first surfactant in the negative electrode material, which is obtained by the procedure described above, is the value shown in the table, the content of the organic shrinkage inhibitor is 0.1 mass%, the content of the barium sulfate is 0.4 mass%, and the content of the carbon black is 0.2 mass%. The negative electrode paste is filled into the mesh part of an expanded lattice made of a Pb-Ca-Sn alloy, and aged and dried to obtain an unformed negative electrode plate.

[0209] As the organic shrink inhibitors shown in the table, the following components are used. (e1) Lignin: Sodium lignosulfonate (sulfur element content 600 μmol / g, Mw 5500) (e2) Bisphenol condensate: Condensation product of a bisphenol compound having a sulfonic acid group introduced therein with formaldehyde (sulfur element content: 5000 μmol / g, Mw: 9600)

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

[0211] (c) Preparation of lead-acid battery A lead-acid battery with a rated voltage of 2V / cell and a rated 5-hour rate capacity of 32Ah is fabricated. The plate group of the lead-acid battery is composed of seven positive plates and seven negative plates. The negative plates are contained in a pouch-shaped separator made of a microporous polyethylene film and are stacked alternately with the positive plates to form a plate group. The plate group is placed in a polypropylene container together with an electrolyte (aqueous sulfuric acid solution) and chemical formation is performed inside the container to fabricate a liquid-type lead-acid battery. The specific gravity of the electrolyte in a fully charged lead-acid battery at 20°C is 1.28.

[0212] (2) Evaluation (a) Overcharged electricity The integrated value of the overcharged quantity of electricity of the lead-acid batteries is obtained by the above-mentioned procedure. The overcharged quantity of electricity of each lead-acid battery is evaluated as a ratio when the integrated value of the overcharged quantity of electricity of the lead-acid battery C1 is set to 100.

[0213] (b) Charge acceptance The lead-acid batteries are measured for 10 seconds by the above-mentioned procedure. The charge acceptance of each lead-acid battery is evaluated based on the ratio of the accumulated amount of electricity of the lead-acid battery C1 to 100.

[0214] The results are shown in Tables 1 to 4. The tables also show the ratio (A) / (B) of the evaluation result of charge acceptance (A) to the evaluation result of overcharge quantity of electricity (B). When the ratio (A) / (B) is 1 or less, it indicates an excellent balance between high charge acceptance and low overcharge quantity of electricity. In the tables, the Mn of the surfactant is the Mn of the surfactant used in preparing the negative electrode material. E1 to E20 are examples, and C1 to C7 are comparative examples. Table 4 also shows the specific surface area of ​​the carbonaceous material contained in the negative electrode material.

[0215] [Table 1]

[0216] As shown in Table 1, when the negative electrode material contains tetramethylammonium chloride or tetrapropylammonium chloride, which is a second surfactant other than the first surfactant, the charge acceptance is improved compared to when no surfactant is contained, but the overcharge charge cannot be reduced or the effect of reduction is very small (comparison of C1 with C2 and C3). However, when the negative electrode material contains the first surfactant, the overcharge charge can be reduced while maintaining a relatively high charge acceptance (E1 to E10).

[0217] From the viewpoint of ensuring higher charge acceptance, it is preferable that the negative electrode material contains a first surfactant of ester type (including ester ether type). From the same viewpoint, the HLB of the first surfactant is preferably 10 or less or 9 or less, and more preferably 8.5 or less.

[0218] [Table 2]

[0219] From the viewpoint of easily ensuring higher charge acceptance, the content of the first surfactant in the negative electrode material is preferably 600 ppm or less or 500 ppm or less, more preferably 400 ppm or less or 350 ppm or less, and may be 300 ppm or less. From the viewpoint of further reducing the overcharge electricity quantity, the content of the first surfactant in the negative electrode material is preferably 30 ppm or more, and may be 36 ppm or more.

[0220] [Table 3]

[0221] As can be seen from Table 3, when a condensate of a bisarene compound is used as an organic shrink inhibitor, a higher charge acceptance can be ensured than when a lignin compound is used.

[0222] [Table 4]

[0223] As shown in Table 4, when the negative electrode material does not contain the first surfactant, as the specific surface area of ​​the carbonaceous material increases, the charge acceptance increases, but the overcharge quantity of electricity tends to increase. When the negative electrode material contains the first surfactant, even if the specific surface area of ​​the carbonaceous material increases, the overcharge quantity of electricity can be reduced while maintaining a relatively high charge acceptance. [Industrial Applicability]

[0224] The lead-acid battery according to one aspect of 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 (such as automobiles and motorcycles) and industrial power storage devices (such as power sources for electric vehicles (such as forklifts)). Note that these are merely examples, and the uses of the lead-acid battery are not limited to these. [Explanation of symbols]

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

Claims

1. A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate comprises a negative electrode material, The negative electrode material includes a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups, At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms, The HLB of the nonionic surfactant is 10 or less, A lead-acid battery, wherein the content of the nonionic surfactant in the negative electrode material is 8 ppm or more and 400 ppm or less by mass.

2. A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate comprises a negative electrode material, The negative electrode material includes a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups, At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms, The content of the nonionic surfactant in the negative electrode material is 8 ppm or more and 400 ppm or less by mass, The nonionic surfactant contains a fatty acid ester of a hydroxy compound having a number average molecular weight Mn of 3000 or less, The long-chain aliphatic hydrocarbon group is derived from a fatty acid of the fatty acid ester.

3. The lead acid battery according to claim 1 or 2, wherein the HLB of the nonionic surfactant is 4 or more.

4. The lead acid battery according to claim 2 , wherein the HLB of the nonionic surfactant is 18 or less.

5. The nonionic surfactant comprises a fatty acid ester of a hydroxy compound, 2. The lead-acid battery according to claim 1, wherein the long-chain aliphatic hydrocarbon group is derived from a fatty acid of the fatty acid ester.

6. The lead acid battery according to any one of claims 1 to 4, wherein at least one of the hydrophilic groups includes a polyoxyethylene chain.

7. The lead acid battery according to claim 2 or 5, wherein the nonionic surfactant comprises at least one selected from the group consisting of a fatty acid ester of polyethylene glycol, a fatty acid ester of a polyethylene oxide adduct of a polyol, and a fatty acid ester of a polyol.

8. The lead acid battery according to any one of claims 1 to 7, wherein the long-chain aliphatic hydrocarbon group has a carbon number of 26 or less.

9. The lead acid battery according to any one of claims 1 to 8, wherein the content of the nonionic surfactant in the negative electrode material is 30 ppm or more by mass.

10. The lead acid battery according to any one of claims 1 to 9, wherein the negative electrode material comprises a condensate of a bisarene compound.

11. The negative electrode material comprises a lignin compound, 3. The lead acid battery according to claim 1, wherein the content of the nonionic surfactant in the negative electrode material is less than 300 ppm by mass.

12. A lead-acid battery, The lead-acid battery includes at least one cell including a plate group and an electrolyte; the electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate, The negative electrode plate comprises a negative electrode material, The negative electrode material includes a condensate of a bisarene compound, The negative electrode material includes a nonionic surfactant having one or more hydrophobic groups and one or more hydrophilic groups, At least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms, The content of the nonionic surfactant in the negative electrode material is 8 ppm or more and less than 500 ppm by mass, The nonionic surfactant contains a fatty acid ester of a hydroxy compound having a number average molecular weight Mn of 3000 or less, The long-chain aliphatic hydrocarbon group is derived from a fatty acid of the fatty acid ester.

Images