Lead-acid battery

Abstract

In this lead-acid battery, a positive electrode plate comprises a plurality of porous tubes, a core metal, a positive electrode material, and a current collector. The positive electrode material includes 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm3 or more. The tube includes an oxygen-containing organic compound, and the LC / MS spectrum of the oxygen-containing organic compound measured with chloroform as a solvent has multiple peaks in a region where the m / z value is 400-2000. The multiple peaks are present at intervals of m / z values 20-25 and 40-50. All oxygen atoms in the oxygen-containing organic compound are contained in at least one of an ether bond and a hydroxyl group. The ratio of the total mass of oxygen atoms in the oxygen-containing organic compound to the mass of the oxygen-containing organic compound is less than 0.320. The mass of the oxygen-containing organic compound contained in the tube is 0.03-0.6 mass% of the mass of the electrolyte.

Description

lead acid battery

[0001] This invention relates to a lead-acid battery.

[0002] Patent Document 1 proposes "an active material holding member comprising a glass tube containing paraffin, wherein the paraffin content is greater than 0% by mass and less than 1.2% by mass, based on the total mass of the glass tube."

[0003] Patent Document 2 proposes a current collector for a clad lead-acid battery, comprising a core metal formed by casting a lead alloy, wherein the lead alloy contains 3.0% to 7.0% by mass of antimony relative to the total mass of the lead alloy, and the core metal is formed by casting the lead alloy by a pressure casting method.

[0004] Patent Document 3 states, "The positive electrode material has a density of 3.1 g / cm³." ３ The present invention proposes a lead-acid battery that, in addition to the above, contains Sb element, and is characterized in that the organic shrinkage inhibitor in the negative electrode material contains 3800 μmol / g or more of S element.

[0005] Patent Document 4 describes a battery separator comprising a porous membrane containing a polyolefin substrate containing polyethylene, 1 to 20% of rubber selected from the group consisting of natural rubber and latex containing polyisoprene, and at least one performance-enhancing additive, wherein the at least one performance-enhancing additive is a surfactant, and the surfactant comprises one from the group consisting of nonionic surfactants, ionic surfactants, anionic surfactants, cationic surfactants, and combinations thereof, and the surfactant is 0.5 g / m ２ ~20g / m ２ The present invention proposes a battery separator in which a certain amount exists, and at least a portion of the surface of the porous membrane is coated with rubber.

[0006] Patent Document 5 proposes a "positive electrode plate for a clad-type lead-acid battery, in which a positive electrode active material is filled inside a tube braided with acid-resistant and oxidation-resistant fibers, characterized in that a first resin layer is formed on the surface of the fibers of the tube, and a second resin layer is formed on the surface of the first resin layer."

[0007] International Publication No. 2021-005722, Japanese Patent Publication No. 2016-162501, Japanese Patent Publication No. 2016-225113, Japanese Patent Publication No. 2022-133405, Japanese Patent Publication No. 2001-325952

[0008] In lead-acid batteries equipped with clad positive electrodes, reducing the density of the positive electrode material is an effective way to increase capacity, but this makes the positive electrode material more prone to softening, thus reducing battery life. In contrast, adding antimony (Sb) to the positive electrode material allows for both increased capacity and maintenance of battery life when using the lead-acid battery at room temperature. Sb has the effect of strengthening the bonds between positive electrode active materials, thereby suppressing the softening of the positive electrode material.

[0009] However, when using lead-acid batteries at high temperatures, a large amount of Sb leaches from the positive electrode material and positive electrode current collector and deposits on the negative electrode plate. This lowers the hydrogen overpotential of the negative electrode plate, leading to insufficient charging of the negative electrode plate, which in turn makes it easier for lead sulfate to accumulate, significantly reducing its lifespan.

[0010] One aspect of the present invention is a lead-acid battery comprising a clad positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the clad positive electrode plate comprises a plurality of porous tubes, a core metal housed within the tubes, a positive electrode material filled within the tubes, and a current collector connecting one end of the plurality of core metals arranged in a row in the longitudinal direction, wherein the positive electrode material contains 0.03% by mass or more of Sb, and the density of the positive electrode material is 3.2 g / cm³. ３The present invention relates to a lead-acid battery wherein the tube contains an oxygen-containing organic compound, the LC / MS spectrum of the oxygen-containing organic compound measured with chloroform as the solvent has multiple peaks in the region where the m / z value is 400 or more and 2000 or less, the multiple peaks are spaced apart with m / z values ​​of 20 or more and 25 or 40 or more and 50 or less, all oxygen atoms contained in the oxygen-containing organic compound are contained in at least one of an ether bond and a hydroxyl group, the ratio of the total mass of the oxygen atoms contained in the oxygen-containing organic compound to the mass of the oxygen-containing organic compound is less than 0.320, and the mass of the oxygen-containing organic compound contained in the tube is 0.03 to 0.5% by mass of the mass of the electrolyte.

[0011] According to the present invention, it is possible to provide a lead-acid battery that can maintain a good lifespan even when used at high temperatures.

[0012] This is a schematic perspective view showing an example of a liquid lead-acid battery with the lid removed according to an embodiment of the present invention. This is a front view of the lead-acid battery in Figure 1. This is a schematic cross-sectional view of the cross section along line IIB-IIB in Figure 2A, viewed from the direction of the arrow. This is a schematic enlarged view of a part of the positive electrode plate in Figure 2B. This is a schematic top view showing a clad positive electrode plate according to an embodiment of the present invention. This is a side view of the clad positive electrode plate in Figure 3A. This is a schematic cross-sectional view of the cross section along line II-II in Figure 3A, viewed from the direction of the arrow.

[0013] The embodiments of this disclosure will be described below with examples, but this disclosure is not limited to the examples described below. In the following description, specific numerical values ​​and materials may be given as examples, but other numerical values ​​and materials may be applied as long as the effects of this disclosure are obtained. In this specification, the description "numerical value A to numerical value B" includes numerical value A and numerical value B, and can be read as "greater than or equal to numerical value A and less than or equal to numerical value B". In the following description, when lower and upper limits of numerical values ​​relating to specific physical properties or conditions are given as examples, either of the given lower limits and either of the given upper limits can be arbitrarily combined, as long as the lower limit is not greater than or equal to the upper limit. When multiple materials are given as examples, one of them may be selected and used alone, or two or more may be used in combination.

[0014] Furthermore, this disclosure encompasses any combination of matters described in two or more claims arbitrarily selected from the multiple claims set forth in the attached claims. In other words, any combination of matters described in two or more claims arbitrarily selected from the multiple claims set forth in the attached claims is possible, as long as it does not result in a technical inconsistency.

[0015] A lead-acid battery comprises a positive electrode plate, a negative electrode plate, a separator interposed between the positive and negative electrode plates, and an electrolyte. The electrolyte contains sulfuric acid. Charging and discharging proceed through the movement of sulfate ions between the positive and negative electrode plates and the electrolyte. During discharge, sulfate ions move to the positive and negative electrode plates. During charging, sulfate ions move from the positive and negative electrode plates into the electrolyte.

[0016] The positive electrode plate, negative electrode plate, and separator constitute an electrode group. An electrode group typically includes multiple positive electrode plates, multiple negative electrode plates, and a separator interposed between the positive and negative electrode plates. The positive and negative electrode plates are stacked alternately with the separator in between. The electrode group, together with the electrolyte, constitutes a cell. One electrode group constitutes one cell. A lead-acid battery comprises one or more cells by comprising one or more electrode groups. There is no particular limit to the number of positive and negative electrode plates included in a single electrode group. If a lead-acid battery comprises multiple electrode groups, they are usually housed in separate cell chambers and connected in series with one another.

[0017] The positive electrode plate includes a positive electrode current collector and a positive electrode material. The positive electrode material is a positive electrode active material that exhibits capacity through oxidation-reduction reactions, and contains at least lead dioxide during charging and at least lead sulfate during discharge.

[0018] The negative electrode plate includes a negative electrode current collector and a negative electrode material. The negative electrode material is a negative electrode active material that exhibits capacity through oxidation-reduction reactions, and contains at least lead during charging and at least lead sulfate during discharging.

[0019] The electrolytic cell has a bottom, side walls rising from the periphery of the bottom, and a lid covering the open end of the side walls. When there are a plurality of electrode plate groups included in the lead-acid battery, the interior of the electrolytic cell may be divided into a plurality of spaces by partition walls. The plurality of partition walls may intersect with each other and be divided into a plurality (for example, four or more) of cell chambers.

[0020] In the present disclosure, at least the following technologies are disclosed.

[0021] (1) A liquid lead-acid battery according to an embodiment of the present disclosure (hereinafter also referred to as "lead-acid battery (LA)") is a lead-acid battery including a clad-type positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolytic solution, wherein the clad-type positive electrode plate includes a plurality of porous tubes, a core metal accommodated in the tubes, a positive electrode material filled in the tubes, and a current collecting portion connecting one end portions in the length direction of the plurality of core metals arranged in a row, the positive electrode material contains 0.03 mass% or more of Sb, the density of the positive electrode material is 3.2 g / cm ３ or more, the tubes contain an oxygen-containing organic compound (hereinafter also referred to as "oxygen-containing organic compound (P)"), and the mass of the oxygen-containing organic compound contained in the tubes is 0.03 to 0.5 mass% of the mass of the electrolytic solution. Note that the core metal and the current collecting portion constitute a positive electrode current collector.

[0022] The oxygen-containing organic compound (P) has the following characteristics (A) to (D). (A) The LC / MS spectrum of the oxygen-containing organic compound measured using chloroform as a solvent has a plurality of peaks in the region where the m / z value (m represents the mass of the ion species and Z represents the charge number of the ion species) is 400 or more and 2000 or less.

[0023] (B) The plurality of peaks exist at intervals where the m / z value is 20 or more and 25 or less, or 40 or more and 50 or less. Note that peaks existing at intervals where the m / z value is 20 to 25 and peaks existing at intervals where the m / z value is 40 to 50 may coexist.

[0024] (C) All oxygen atoms contained in the oxygen-containing organic compound are included in at least one of an ether bond and a hydroxy group.

[0025] (D) The ratio of the total mass of oxygen atoms contained in the oxygen-containing organic compound to the mass of the oxygen-containing organic compound (hereinafter also referred to as "oxygen content (PO)") is less than 0.320.

[0026] The lead-acid battery (LA) described in (1) above can maintain a good lifespan even when used at high temperatures. In other words, the lead-acid battery (LA) has good high-temperature cycle life performance. Specifically, the lead-acid battery (LA) has a clad positive electrode tube containing an oxygen-containing organic compound (P), which has the effect of capturing Sb that dissolves from the positive electrode. The core metal, which is the main part of the positive electrode material and positive electrode current collector, is filled inside the tube. When used at high temperatures, a large amount of Sb may dissolve from the positive electrode, but both the Sb that dissolves from the positive electrode material and the Sb that dissolves from the positive electrode current collector must pass through the tube in order to move to the negative electrode. Therefore, Sb is efficiently captured by the oxygen-containing organic compound (P) before it diffuses into the electrolyte outside the tube, and the deposition of Sb on the negative electrode is significantly suppressed.

[0027] Even when oxygen-containing organic compounds (P) are added to the separator, electrolyte, or negative electrode material, when lead-acid batteries are used at high temperatures, Sb is captured by the oxygen-containing organic compounds (P), and Sb deposition on the negative electrode plate is suppressed. On the other hand, when lead-acid batteries are used at high temperatures, a large amount of Sb leaches out from the positive electrode plate. Therefore, the oxygen-containing organic compounds (P) added to the separator, electrolyte, or negative electrode material cannot adequately capture Sb, and Sb deposition on the negative electrode plate cannot be suppressed, resulting in a significant reduction in lifespan. Under conditions where a large amount of Sb leaches out from the positive electrode plate, it is necessary to include oxygen-containing organic compounds (P) in the positive electrode plate tube.

[0028] Furthermore, in the lead-acid battery (LA) described in (1) above, the battery capacity is also improved by the action of oxygen-containing organic compounds (P) contained in the positive electrode tube. Specifically, some of the oxygen-containing organic compounds (P) migrate to the positive electrode material and are adsorbed onto the positive electrode active material, where they are electrolyzed during charging. The decomposition of the oxygen-containing organic compounds (P) forms fine pores in the positive electrode material. These pores differ in size and properties from those formed when the density of the positive electrode material is reduced, and are maintained over the long term, promoting the flow of the electrolyte. Therefore, an improvement in battery capacity and a significant improvement in lifespan are achieved that cannot be obtained by reducing the density of the positive electrode material alone. In other words, battery capacity and lifespan can be improved to a level that cannot be achieved by reducing the density of the positive electrode material alone.

[0029] Because oxygen-containing organic compounds (P) are highly hydrophilic, they tend to remain in the tube. However, oxygen-containing organic compounds (P) gradually dissolve from the tube into the electrolyte during charge-discharge cycles. The amount of dissolution increases with the amount of electrolyte. Therefore, by controlling the mass of oxygen-containing organic compounds (P) contained in the tube based on the mass of the electrolyte, the effect of oxygen-containing organic compounds (P) can be maximized.

[0030] The ratio of the mass of oxygen-containing organic compound (P) contained in the tube to the mass of the electrolyte is preferably, for example, 0.03% by mass or more, more preferably 0.05% by mass or more, and may also be 0.1% by mass or more. The ratio of the mass of oxygen-containing organic compound (P) contained in the tube to the mass of the electrolyte is preferably, for example, 0.6% by mass or less or 0.5% by mass or less, and may also be 0.4% by mass or less, or 0.3% by mass or less. The ratio of the mass of oxygen-containing organic compound (P) contained in the tube to the mass of the electrolyte is, for example, in the range of 0.03% by mass to 0.6% by mass, in the range of 0.03% by mass to 0.5% by mass, in the range of 0.1% by mass to 0.4% by mass, or in the range of 0.1% by mass to 0.3% by mass.

[0031] If the mass of oxygen-containing organic compounds (P) in the tube is less than 0.03% by mass of the electrolyte, it becomes difficult to adequately capture Sb, which leaches out in large quantities from the positive electrode plate during high-temperature operation of the lead-acid battery, even if oxygen-containing organic compounds (P) are included in the tube. Furthermore, if the mass of oxygen-containing organic compounds (P) in the tube exceeds 0.5% by mass of the electrolyte, the oxygen-containing organic compounds (P) inhibit the movement of sulfate ions. As a result, initially, sulfate ions have difficulty penetrating the tube, leading to a decrease in capacity, and as the charge-discharge cycle progresses, sulfate ions have difficulty being released from the positive electrode plate, making it easier for lead sulfate to accumulate. Consequently, it becomes difficult to maintain a good lifespan.

[0032] (2) In the lead-acid battery (LA) described in (1) above, the density of the positive electrode material is 3.2 g / cm³. ３ ~3.8 g / cm ３ That's fine.

[0033] In the lead-acid battery (LA) described in (2) above, a high battery capacity can be obtained because the density of the positive electrode material is designed to be low. The lower the density of the positive electrode material, the greater the effect of suppressing Sb deposition when the lead-acid battery is used at high temperatures.

[0034] (3) In the lead-acid battery (LA) described in (1) or (2) above, the core metal and the current collector are made of, for example, a Pb-Sb alloy. The Pb-Sb alloy preferably contains 0.01% to 0.1% by mass of Sn.

[0035] In the lead-acid battery (LA) described in (3) above, the core metal and current collector constituting the positive electrode current collector are made of a Pb-Sb alloy containing Sn, which improves the initial battery capacity. This is thought to be because the adhesion between the initial positive electrode current collector and the positive electrode material is improved, suppressing the formation of a resistive layer.

[0036] (4) In the lead-acid battery (LA) described in any one of (1) to (3) above, the positive electrode material preferably contains 0.05% to 0.4% by mass of Sb.

[0037] In the lead-acid battery (LA) described in (4) above, the strength of the positive electrode material is very high, so even if the density of the positive electrode material is reduced, it is possible to maintain a better lifespan. When the lead-acid battery (LA) is used at high temperatures, as previously mentioned, a large amount of Sb may leach from the positive electrode plate, but the diffusion of Sb is suppressed by applying an oxygen-containing organic compound (P) to the tube.

[0038] (5) In the lead-acid battery (LA) described in any one of (1) to (4) above, the height of the positive electrode plate and the negative electrode plate may be 200 mm or more.

[0039] The lead-acid battery (LA) described in (5) above has vertically elongated electrode plates of 200 mm or more, which makes the electrolyte prone to stratification. As a result, the negative electrode plate is prone to undercharging, and lead sulfate tends to accumulate. Therefore, the improvement in lifespan by satisfying the above configuration is very significant.

[0040] The Sb-scavenging ability of oxygen-containing organic compounds (P) is due to the good hydrophilicity derived from the oxygen atoms of the oxygen-containing organic compounds (P). Characteristics (A) and (B) originate from the repeating structure containing oxygen. The repeating structure containing oxygen has the effect of capturing Sb. The repeating structure containing oxygen is typically a polyoxyalkylene, but other repeating structures may be used as long as they possess characteristics (A) and (B). Oxygen-containing organic compounds that do not possess characteristics (A) and (B) have low Sb-scavenging ability, and therefore the effects described above cannot be expected. Note that due to the repeating structure, the multiple peaks of characteristic (B) may appear at substantially equal intervals.

[0041] Characteristic (C), in other words, means that the oxygen-containing functional groups that can be contained in the oxygen-containing organic compound (P) are only ether bonds and / or hydroxyl groups, and that they do not contain oxygen atoms found in other functional groups (e.g., ester bonds). Oxygen-containing groups, such as ester bonds, are hydrolyzed in sulfuric acid aqueous solution, and therefore the effects described above cannot be expected.

[0042] Feature (D) means that the oxygen-containing organic compound (P) contains an appropriate amount of oxygen atoms. Oxygen atoms have lone pairs of electrons that enable hydrogen bonding, and the presence of these lone pairs in the oxygen-containing organic compound (P) results in good Sb scavenging ability. If the oxygen content (PO) is 0.320 or higher, the hydrophilicity of the oxygen-containing organic compound (P) is too high, causing an excessive amount of the oxygen-containing organic compound (P) to dissolve into the electrolyte from the tube, making it impossible to retain the oxygen-containing organic compound (P) in the tube.

[0043] As described above, only specific oxygen-containing organic compounds (P) having characteristics (A) to (D) can exist stably in an aqueous sulfuric acid solution and have high Sb-scavenging ability, thus producing the effects described. As a result, a lead-acid battery with good high-temperature cycle life performance can be obtained.

[0044] (6) In the lead-acid battery (LA) described in any one of (1) to (5) above, it is preferable that the LC / MS spectrum of the oxygen-containing organic compound (P) measured with chloroform as a solvent has 10 or more peaks in the region where the m / z value is 400 or more and 1200 or less.

[0045] According to the lead-acid battery (LA) described in (6) above, the balance between hydrophilicity and hydrophobicity of the oxygen-containing organic compound (P) is particularly good. Moderate hydrophobicity suppresses the elution of the oxygen-containing organic compound (P) into the electrolyte. Therefore, the oxygen-containing organic compound (P) tends to remain in the tube for a sufficiently long period of time. On the other hand, because the oxygen-containing organic compound (P) has good hydrophilicity, a moderate amount of the oxygen-containing organic compound (P) moves to the positive electrode material and is adsorbed onto the positive electrode active material, where it is electrolyzed during charging and forms fine pores in the positive electrode material. This improves the fluidity of the electrolyte in the positive electrode material. Therefore, the effect of improving battery capacity while maintaining good high-temperature cycle life performance is greatly enhanced.

[0046] (7) In the lead-acid battery (LA) described in any one of (1) to (6) above, the oxygen-containing organic compound (P) may be an ether having a polyoxyethylene group and a terminal alkyl group or terminal alkenyl group (hereinafter also referred to as "polyoxyethylene-alkyl / alkenyl ether").

[0047] In the lead-acid battery (LA) described in (7) above, the polyoxyethylene alkyl / alkenyl ether is stable to sulfuric acid, difficult to decompose, and has appropriate hydrophilicity and hydrophobicity. Therefore, the quantitative balance between oxygen-containing organic compounds (P) that remain in the tube and oxygen-containing organic compounds (P) that leach from the tube and act on the positive electrode material is improved.

[0048] (8) In the lead-acid battery (LA) described in (7) above, the number of carbon atoms in the terminal alkyl group or terminal alkenyl group is preferably 10 or more and 20 or less.

[0049] In the lead-acid battery (LA) described in (8) above, polyoxyethylene alkyl / alkenyl ethers having 10 to 20 carbon atoms in the terminal alkyl or terminal alkenyl group have an even better balance between the amount that remains in the tube and the amount that dissolves from the tube and acts on the positive electrode material.

[0050] The number of carbon atoms in the terminal alkyl group or terminal alkenyl group may be, for example, 13 or more. The number of carbon atoms in the terminal alkyl group or terminal alkenyl group may be, for example, 18 or less, or 17 or less. The number of carbon atoms in the terminal alkyl group may be, for example, 13 to 18, and preferably in the range of 13 to 17.

[0051] (9) In the lead-acid battery (LA) described in (7) or (8) above, the number N of oxyethylene units in the polyoxyethylene group is preferably 5 or more and 35 or less.

[0052] In the lead-acid battery (LA) described in (9) above, when the number of oxyethylene units N is 5 to 35, a more favorable Sb scavenging ability is exhibited due to the lone pairs of electrons of the oxygen atoms. Furthermore, since the oxygen content (PO) of the oxygen-containing organic compound (P) is limited to a favorable range, the amount of oxygen-containing organic compound (P) that dissolves from the tube into the electrolyte is also limited to a favorable range.

[0053] The number of oxyethylene units N in the polyoxyethylene group may be, for example, 7 to 25, or 10 to 20.

[0054] (10) In the lead-acid battery (LA) described in any one of (1) to (9) above, the oxygen-containing organic compound (P) may be at least one selected from the group consisting of, for example, polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, and polyoxyethylene cetyl ether.

[0055] The lead-acid battery (LA) described in (10) above has better high-temperature cycle life performance and exhibits a higher battery capacity.

[0056] In this specification, a fully charged lead-acid battery refers to a lead-acid battery that has been charged to a fully charged state after chemical formation. The timing for charging a lead-acid battery to a fully charged state can be immediately after chemical formation, or after a certain amount of time has elapsed since chemical formation (e.g., 1440 hours or less). For example, a lead-acid battery that has been chemically formed and is in use (preferably in the early stages of use) may be charged.

[0057] A battery in its initial stages of use is one that has not been used for very long and has not deteriorated significantly (for example, a battery that has been in use for less than 1440 hours, including the time elapsed since its initial use).

[0058] A fully charged liquid-type lead-acid battery is defined as the battery being charged at a current (A) equal to 0.2 times the rated capacity (a value in Ah) at 15-minute intervals in a 25°C ± 2°C water bath, until the terminal voltage (in V) or the electrolyte density (temperature-converted to 20°C) shows a constant value with three significant figures for three consecutive measurements. The rated capacity is expressed in Ah (ampere-hours). The current set based on the rated capacity is in A (amperes).

[0059] The time rate specified for the rated capacity of a lead-acid battery may differ from the time rate specified in the experimental method. In such cases, the converted value of the rated capacity (CW) can be calculated using the time rate specified for the rated capacity, the time rate to be used in the test, and a coefficient. CW = Cx × (W / x) ｙ　　 (y is the exponent of the power) Conversion formula 1 W: Time rate to be converted (time rate to be actually used) Cx: Rated capacity at X time rate X: Time rate for which the rated capacity is specified (different from the time rate specified in the test method) Note that y = 0.1545 can also be used when converting from any of the 3-hour, 5-hour, 10-hour, or 20-hour rates.

[0060] The following explains how to determine various parameters and material properties.

[0061] <Ratio of the mass of oxygen-containing organic compounds in the tube to the mass of the electrolyte> After disassembling a fully charged battery immediately after compounding or in the initial stages of use, the tubes are washed with water and dried. The mass W1 of the dried tubes is measured. The tubes with mass W1 are immersed in chloroform to extract oxygen-containing organic compounds (P), and the mass W2 of oxygen-containing organic compounds (P) in the tubes is quantified by analysis using liquid chromatography. At this time, the tubes are immersed in 5 mL of chloroform per gram, subjected to ultrasound at 20 ± 5°C for 1 hour, and then left overnight (approximately 18 hours) for extraction. One or more entire tubes may be immersed in chloroform. The ratio (%) of the mass of oxygen-containing organic compounds in the tubes to the mass of the electrolyte is calculated as "100 × W2 / (mass of electrolyte)".

[0062] Liquid chromatography is performed under the following conditions. The LC / MS spectrum of the extract is measured, and the concentration of the oxygen-containing organic compound (P) in the dilution is determined by a calibration curve method based on the intensity of the characteristic peak of the oxygen-containing organic compound (P). The calibration curve is prepared in advance using the oxygen-containing organic compound (P) that has been identified by qualitative analysis. Identification of the oxygen-containing organic compound (P) is possible by qualitative analysis, and information can be obtained from at least one of the following for the extract: IR, UV-VIS, NMR, LC / MS, and GC / MS. By identifying the oxygen-containing organic compound (P), the number of carbon atoms in the terminal alkyl group or terminal alkenyl group of the oxygen-containing organic compound (P) and the number of oxyethylene units N in the polyoxyethylene group can be determined.

[0063] LC / MS Spectrometer Measurement Conditions Equipment: LC section (Agilent Technologies 1100 Series), MS section (Bruker Ductonics microOTOF focus type) Column: Unison UK-C8 (3 μm, 2 × 50 mm) Column temperature: 40°C Mobile phase: A mixture of solutions A and B is used, with the mixing ratio of A and B gradually changed from 90:10 to 0:100 over 20 minutes, and only B is used from 20 to 30 minutes. Solution A: 10 mM ammonium formate aqueous solution Solution B: Acetonitrile Flow rate: 0.3 mL / min Detection method: ESI (Pos.) Injection volume: 1 μL

[0064] <Identification of oxygen atoms in oxygen-containing organic compounds> The presence of oxygen atoms in oxygen-containing organic compounds (P) in at least one of the ether bond and the hydroxyl group can be confirmed, for example, by FT-IR.

[0065] <Oxygen Content (PO)> The ratio of the total mass of oxygen atoms contained in an oxygen-containing organic compound (P) to the mass of the oxygen-containing organic compound (P) (oxygen content (PO)) can be measured by the following method. The concentrated extract is heated to 1150°C in a quartz tube filled with carbon particles and burned with nitrogen as the carry gas, causing thermal decomposition by the carbon particles, converting all the oxygen atoms in the resulting decomposition gas into carbon monoxide. The resulting carbon monoxide is oxidized by reacting with copper monoxide to produce carbon dioxide, which is then collected by adsorption by passing it through an absorption tube filled with sodium hydroxide and magnesium perchlorate. The amount of carbon dioxide collected can be determined from the change in mass of the absorption tube at this time. The amount of oxygen in the extract can be determined by converting the amount of carbon dioxide to the amount of oxygen. The oxygen content (PO) can be determined from the amount of oxygen in the extract and the mass W2 of the oxygen-containing organic compound (P) contained in the tube.

[0066] The lead-acid battery (LA) according to an embodiment of the present invention will be described in more detail below with reference to the drawings. However, the present invention is not limited to the following embodiments.

[0067] The following describes examples of components of a lead-acid battery (LA).

[0068] (Positive electrode plate) The positive electrode plate of a lead-acid battery (LA) is clad type. The positive electrode plate comprises a positive electrode current collector and a positive electrode material. The clad type positive electrode plate comprises a plurality of porous tubes, a core inserted into each tube, a current collector connecting one end of each of the plurality of cores, a positive electrode material filled into the tubes into which the cores are inserted, and a connecting seat connecting the plurality of tubes.

[0069] The positive electrode material includes a positive electrode active material that exhibits capacity through oxidation-reduction reactions. The positive electrode active material includes lead dioxide, lead sulfate, etc. The positive electrode material is the portion of the positive electrode plate excluding the tube, core metal, current collector, and connecting seat.

[0070] The connecting seats are typically located at one end of the tube on the current collector side and at the other end opposite the current collector. More specifically, along the length of the tube, the end of the tube on the current collector side is usually secured to the current collector by an upper connecting seat. The other end of the tube is sealed by a lower connecting seat. The upper connecting seat is usually formed by integrally molding resin to cover the top of the core metal and the current collector. The lower connecting seat is usually made of resin and is inserted into the opening at the other end of each tube.

[0071] A clad-type positive electrode plate is formed by housing multiple cores, each connected at one end in the longitudinal direction at the current collector, within multiple tubes, and filling the tubes with lead powder to form an unformed positive electrode plate. More specifically, the unformed positive electrode plate is formed by housing each of the multiple cores within a tube, fixing one end of the multiple tubes to the current collector with an upper connecting seat, filling the tubes with lead powder or the like through the opening at the other end of the tubes, and sealing the openings at the other ends of the multiple tubes with a lower connecting seat. The lead powder contains at least lead monoxide. The lead powder may also contain metallic lead. Alternatively, lead powder and red lead may be used in combination.

[0072] Chemical treatment may be carried out by immersing the electrode plate group, including the untreated positive electrode plate, in the sulfuric acid-containing electrolyte in the lead-acid battery case and charging the electrode plate group. Chemical treatment may also be carried out before the assembly of the lead-acid battery or the electrode plate group.

[0073] (Positive electrode current collector) The positive electrode current collector of a clad-type positive electrode plate consists of a core metal and a current collecting section. The current collecting section usually has lugs formed therein for drawing electricity from the lead-acid battery. The positive electrode current collector may be formed by casting a lead alloy. The casting method is not limited, and gravity casting, die casting, etc., may be used.

[0074] The mandrel is a long, slender rod (for example, a round rod). The diameter of the mandrel (the diameter of a round rod) may be 2.4 mm or more, or 2.7 mm or more, and may be less than 3.6 mm or 3.3 mm or less. For example, the diameter may be 2.4 mm or more and less than 3.6 mm, or 2.7 mm or more and 3.3 mm or less.

[0075] There are no particular limitations on the length of the core wire, and it is selected according to the size of the positive electrode plate. The length of the core wire is preferably 100 mm or more, and may be 200 mm or more. The length of the core wire may be 100 mm to 400 mm, or 200 mm to 400 mm.

[0076] The positive electrode current collector contains the element Sb. That is, the lead alloy used for the positive electrode current collector may be a Pb-Sb alloy. The use of a Pb-Sb alloy improves the mechanical strength of the positive electrode current collector, the adhesion between the positive electrode current collector and the positive electrode material, and the corrosion resistance.

[0077] On the other hand, when a Pb-Sb alloy is used, Sb may dissolve into the electrolyte. If the Sb dissolved in the electrolyte precipitates on the negative electrode plate, the hydrogen generation overpotential of the negative electrode plate decreases, promoting the side reaction of hydrogen generation, which reduces the charging efficiency and causes the negative electrode plate to become undercharged. These phenomena are suppressed when the lead-acid battery satisfies the characteristics described above.

[0078] The Sb content in the positive electrode current collector (Pb-Sb alloy) may be 2.0% by mass or more, or 3.0% by mass or more. The Sb content in the positive electrode current collector may be 10.0% by mass or less, or 6% by mass or less. For example, the Sb content in the positive electrode current collector may be 2.0% by mass or more, or 10.0% by mass or less, or 3.0% by mass or more, and 6.0% by mass or less.

[0079] The Pb-Sb alloy preferably further contains Sn. Sn has the effect of improving the adhesion between the initial positive electrode current collector and the positive electrode material, thereby suppressing the formation of a resistance layer and improving the initial capacity of the lead-acid battery.

[0080] The Sn content in the Pb-Sb alloy is preferably, for example, 0.01% to 0.2% by mass, more preferably 0.01% to 0.15% by mass, and even more preferably 0.01% to 0.1% by mass, considering the balance between the initial capacity and high-temperature cycle life performance of the lead-acid battery.

[0081] Pb-Sb alloys may contain trace elements other than Pb, Sb, and Sn. The content of such trace elements may be more than 0% by mass and 1% by mass or less (for example, more than 0% by mass and 0.5% by mass or less). Examples of such trace elements include As, S, Se, Ag, etc.

[0082] (Method for analyzing the composition of the positive electrode current collector) The quantitative analysis of elements other than lead (including Sb and Sn elements) contained in the positive electrode current collector can be performed in accordance with the lead-separated inductively coupled plasma emission spectroscopy described in JIS H2105. When analyzing the elemental content of the positive electrode current collector of a positive electrode plate removed from a lead-acid battery, first, the positive electrode plate is vibrated to detach the positive electrode material from the positive electrode current collector, and then the remaining positive electrode material around the positive electrode current collector is removed using a ceramic knife. After that, a portion of the positive electrode current collector with metallic luster is taken as a sample and its mass is measured. The collected sample is dissolved in tartaric acid and dilute nitric acid to obtain an aqueous solution. Hydrochloric acid is added to the obtained aqueous solution to precipitate lead chloride, and the solution is filtered and the filtrate is collected. The elements in the filtrate are analyzed using a calibration curve method with an inductively coupled plasma (ICP) emission spectrometer (e.g., ICPS-8000, manufactured by Shimadzu Corporation). From the above analysis results, the elemental content (mass%) in the positive electrode current collector is determined.

[0083] (Positive electrode material) The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that exhibits capacity through an oxidation-reduction reaction. The positive electrode material contains the element Sb and may contain other additives as needed.

[0084] The Sb content in the positive electrode material is 0.03% by mass or more, may be 0.04% by mass or more, or may be 0.05% by mass or more. When the Sb content is within this range, the softening of the positive electrode material is significantly suppressed. When the Sb content in the positive electrode material becomes somewhat high, the effect of suppressing the softening of the positive electrode material tends to plateau. Therefore, the Sb content in the positive electrode material may be 0.5% by mass or less, or 0.4% by mass or less.

[0085] The content rate of Sb element in the positive electrode material may be 0.03 mass% or more and 0.5 mass% or less, may be 0.04 mass% or more and 0.5 mass% or less, preferably 0.05 mass% or more and 0.5 mass% or less, and more preferably 0.05 mass% or more and 0.4 mass% or less.

[0086] In order to include the Sb element in the positive electrode material, an Sb source may be included in the raw material of the positive electrode material. As the Sb source, Sb ２ O ３ is preferable, but metallic Sb, antimony oxyoxide, Sb ２ O ５ etc. may be used, or a Pb-Sb alloy system may be made into powder and used as the Sb source. Note that the Sb element can also be supplied from the Pb-Sb alloy of the core wire.

[0087] Considering the balance between the effect of improving the battery capacity and the high-temperature cycle life performance, the density of the positive electrode material is preferably 3.2 g / cm ３ or more. From the viewpoint of the battery capacity, the density of the positive electrode material is, for example, 4.0 g / cm ３ or less, may be 3.8 g / cm ３ or less, may be 3.6 g / cm ３ or less, may be 3.5 g / cm ３ or less, may be 3.4 g / cm ３ or less.

[0088] The density of the positive electrode material is the bulk density of the positive electrode material (unit: g / cm ３ ). The bulk density is obtained by dividing the mass of the positive electrode material (unit: g) by the bulk volume of the positive electrode material (unit: cm ３ ). The bulk volume is obtained by the mercury intrusion method. The bulk density is obtained for a sample of the unground positive electrode material collected from the positive electrode plate taken out from the fully charged lead storage battery. The unground sample is collected from near the center in the plane direction of the positive electrode plate.

[0089] (Analysis of the positive electrode material) The positive electrode material is collected from the positive electrode plate taken out from the fully charged lead storage battery.

[0090] (Sb content) First, a fully charged lead-acid battery is disassembled to obtain the positive electrode plate to be analyzed. The obtained positive electrode plate is washed with water for 3 to 4 hours to remove the electrolyte from the positive electrode plate. The washed positive electrode plate is dried in a constant temperature bath at 60°C ± 5°C for 5 hours or more. After drying, an appropriate amount of positive electrode material is taken and the mass of the sample is measured. Next, the entire sample is dissolved in a mixed aqueous solution containing tartaric acid, nitric acid, and hydrogen peroxide. The solution obtained by total dissolution is diluted with deionized water as needed to a fixed volume, and then the emission intensity of Sb in the solution is measured by inductively coupled plasma (ICP) emission spectroscopy. Then, the mass of Sb contained in the solution is determined using a calibration curve prepared in advance. The ratio of this Sb mass to the mass of the positive electrode material sample subjected to analysis is determined as the Sb content.

[0091] (Density of positive electrode material) Similarly to the above, an appropriate amount of dried positive electrode material is taken, and its density (bulk density) is determined by the mercury intrusion method using a mercury porosimeter. More specifically, first, a predetermined amount of unground sample is taken and its mass is measured. This sample is placed in the measuring container of the mercury porosimeter, evacuated under reduced pressure, and then filled with mercury at a pressure of 0.5 psia to 0.55 psia (≒ 3.45 kPa to 3.79 kPa). The bulk volume of the sample is measured, and the density of the positive electrode material is determined by dividing the measured mass of the sample by the bulk volume. The bulk volume is defined as the volume of the measuring container minus the volume of mercury injected. As the mercury porosimeter, an automatic porosimeter (Autopore IV9505) manufactured by Shimadzu Corporation can be used. If the electrode plate group includes one positive electrode plate, the density of the positive electrode material is determined for the positive electrode material taken from that positive electrode plate. If the electrode group includes two positive electrodes, the density of the positive electrode material is the average value obtained from the positive electrode material sampled from each of the two positive electrodes. If the electrode group includes three positive electrodes, the density is the value obtained from the positive electrode material sampled from the central positive electrode. If the electrode group includes four or more positive electrodes, the density of the positive electrode material is the average value obtained from the positive electrode material sampled from any two positive electrodes other than the two end electrodes of the electrode group.

[0092] The porous tube only needs to be able to house a core metal inside and hold the positive electrode material. The porous tube is usually a tubular fiber assembly. As the tubular fiber assembly, a fiber assembly made by weaving fibers into a tube shape may be used, or a tubular nonwoven or woven fabric may be used. Examples of fibers include inorganic fibers (such as glass fibers) and resin fibers. However, the fibers are not limited to these. The porous tube may be heat-treated as needed. The tubular fiber assembly may be impregnated with resin.

[0093] The length of the tube should be selected according to the length of the core. The outer diameter and thickness of the tube should be selected, for example, according to the shape of the core or the application of the lead-acid battery. The tube contains an oxygen-containing organic compound (P). The method of impregnating the tube with the oxygen-containing organic compound (P) is not particularly limited. For example, the tube may be impregnated with the oxygen-containing organic compound (P) by impregnation, immersion, vapor deposition, spraying, coating, etc. Specifically, a concentrated solution of the oxygen-containing organic compound (P) may be sprayed onto the surface of the tube and dried to coat the surface with the oxygen-containing organic compound (P). Alternatively, the tube may be immersed in a concentrated solution of the oxygen-containing organic compound (P). Furthermore, fibers containing the oxygen-containing organic compound (P) may be used when manufacturing the tube. The concentration of the concentrated solution of the oxygen-containing organic compound (P) may be, for example, 30% to 90% by mass. Organic solvents such as chloroform, hexane, acetone, and ethanol may be used as solvents.

[0094] (Negative electrode plate) The negative electrode plate comprises a negative electrode current collector and a negative electrode material. The negative electrode material is held by the negative electrode current collector. The negative electrode material is the portion of the negative electrode plate excluding the negative electrode current collector. Note that adhesive members such as conductive layers, mats, and pasting paper may be attached to the negative electrode plate. The adhesive members are included as components of the negative electrode plate. When the negative electrode plate includes adhesive members, the negative electrode material is the portion of the negative electrode plate excluding the negative electrode current collector and the adhesive members.

[0095] The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or by processing a lead or lead alloy sheet. The processing method may be expansion or punching. Using a grid-like current collector as the negative electrode current collector makes it easier to support the negative electrode material.

[0096] The lead alloy used for the negative electrode current collector may be any of the following: a Pb-Sb alloy, a Pb-Ca alloy, or a Pb-Ca-Sn alloy. The lead alloy used for the negative electrode current collector may also contain at least one additive element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu, etc. The negative electrode current collector may have metal layers of different compositions, and the metal layers may be one layer or multiple layers.

[0097] The negative electrode material contains a negative electrode active material that exhibits capacity through an oxidation-reduction reaction. The negative electrode active material includes lead, lead sulfate, and the like.

[0098] The negative electrode material may contain additives as needed. Such additives may include organic shrinkage inhibitors, carbonaceous materials, barium sulfate, and the like.

[0099] Organic shrinkage inhibitors that can be used include lignin, lignin derivatives, and synthetic organic shrinkage inhibitors (such as formaldehyde condensates of phenol compounds). Examples of lignin derivatives include lignin sulfonic acid or its salts (such as alkali metal salts). The negative electrode material may contain one organic shrinkage inhibitor or two or more.

[0100] The content of the organic shrinkage inhibitor in the negative electrode material is, for example, 0.01% by mass or more and 1% by mass or less, and may be 0.03% by mass or less and 0.6% by mass or less.

[0101] As the formaldehyde condensate of the phenol compound, a condensate of a bisphenol compound with at least one selected from the group consisting of sulfite compounds and amino acid compounds and an aldehyde compound is preferred.

[0102] Carbonaceous materials that can be used include carbon black, artificial graphite, natural graphite, hard carbon, and soft carbon. A single carbonaceous material may be used, or two or more may be used in combination.

[0103] The carbonaceous material content in the negative electrode material is, for example, 0.1% by mass or more and 3% by mass or less.

[0104] The barium sulfate content in the negative electrode material is, for example, 0.1% by mass or more and 3% by mass or less.

[0105] The negative electrode plate is obtained by chemically converting an unconverted negative electrode plate. The unconverted negative electrode plate is obtained by filling a negative electrode current collector with negative electrode paste, allowing it to mature, and drying. The negative electrode paste is prepared by kneading a mixture containing lead powder, water, and sulfuric acid. The negative electrode paste may optionally contain organic shrinkage inhibitors, carbonaceous materials, barium sulfate, etc.

[0106] The chemical treatment may be carried out by immersing the electrode plate group, including the untreated negative electrode plate, in an electrolyte containing sulfuric acid in the lead-acid battery case, thereby charging the electrode plate group. The chemical treatment may also be carried out before the assembly of the lead-acid battery or the electrode plate group. The charged negative electrode active material contains spongy lead.

[0107] (Separator) A separator may be placed between the negative electrode plate and the positive electrode plate. As the separator, at least one selected from nonwoven fabric and microporous membrane can be used.

[0108] Nonwoven fabrics are mats made by intertwining fibers without weaving, and are primarily composed of fibers. For example, nonwoven fabrics are made up of 60% or more by mass of fibers. As fibers, glass fibers, oxygen-containing organic fibers (polyolefin fibers, acrylic fibers, polyester fibers (polyethylene terephthalate fibers, etc.), etc.), pulp fibers, etc. may be used. Among these, glass fibers are preferred. Nonwoven fabrics may also contain components other than fibers (for example, acid-resistant inorganic powders, binders, etc.).

[0109] On the other hand, a microporous membrane is a porous sheet mainly composed of components other than fibers, 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. Microporous membranes are preferably composed of acid-resistant materials, and microporous membranes mainly composed of oxygen-containing organic components are preferred. As the oxygen-containing organic component, polyolefins (polyethylene, polypropylene, etc.) are preferred. As the pore-forming agent, at least one selected from the group consisting of oxygen-containing organic powders and oils can be mentioned.

[0110] The separator may be composed of, for example, only a nonwoven fabric, or only a microporous membrane. Alternatively, the separator may be a laminate of a nonwoven fabric and a microporous membrane, if necessary.

[0111] (Electrolyte) The electrolyte is an aqueous solution containing sulfuric acid, which may be gelled if necessary. The electrolyte may optionally contain cations (e.g., metal cations) and / or anions (e.g., anions other than sulfate anions (e.g., phosphate ions)). Examples of metal cations include at least one selected from the group consisting of Na ions, Li ions, Mg ions, and Al ions.

[0112] The density of the electrolyte in a fully charged lead-acid battery at 20°C is, for example, 1.20 g / cm³. ３ The above is 1.25 g / cm³. ３ The above may also be acceptable. The density of the electrolyte at 20°C is, for example, 1.35 g / cm³. ３ The following is the value: 1.32 g / cm³ ３ The following is preferable:

[0113] Furthermore, simply adding an appropriate amount of oxygen-containing organic compound (P) to the electrolyte in a quantity that does not affect battery performance will not produce the same effect as when the oxygen-containing organic compound (P) is included in the tube. In that case, the oxygen-containing organic compound (P) will not be detectable in the tube, or if it is detected, it will be in a very small amount. If the ratio of the mass of the oxygen-containing organic compound contained in the tube to the mass of the electrolyte is, for example, less than 0.01% by mass (and even less than 0.005% by mass), the separator cannot be said to substantially contain the oxygen-containing organic compound (P).

[0114] Figure 1 is a schematic perspective view showing an example of a lead-acid battery according to an embodiment of the present invention with the lid removed. Figure 2A is a front view of the lead-acid battery of Figure 1, and Figure 2B is a schematic cross-sectional view of the cross section along the line IIB-IIB in Figure 2A, viewed from the direction of the arrow. Figure 2C is an enlarged view of a part of Figure 2B.

[0115] The lead-acid battery 1 comprises a battery case 10 that houses an electrode plate group 11 and an electrolyte 12. The electrode plate group 11 is composed of multiple negative electrode plates 2 and clad-type positive electrode plates 3 stacked together with separators 4 in between. The negative electrode plates 2 are enclosed within the separators 4, which are formed in a cylindrical shape.

[0116] Each of the multiple negative electrode plates 2 has an upwardly protruding current-collecting tab (not shown) on its upper part. Each of the multiple clad-type positive electrode plates 3 also has an upwardly protruding current-collecting tab (not shown) on its upper part. The tabs of the negative electrode plates 2 are connected and integrated by a negative electrode strap 5a. Similarly, the tabs of the clad-type positive electrode plates 3 are connected and integrated by a positive electrode strap 5b. The lower end of the negative electrode column 6a is fixed to the upper part of the negative electrode strap 5a, and the lower end of the positive electrode column 6b is fixed to the upper part of the positive electrode strap 5b.

[0117] Figure 3A is a schematic top view showing a clad positive electrode plate 3 according to an embodiment of the present invention. Figure 3B is a side view of the clad positive electrode plate 3 of Figure 3A, viewed from the side opposite to the lug portion 34a. Figure 3C is a schematic cross-sectional view of the cross section along line II-II of Figure 3A, viewed from the direction of the arrow.

[0118] The clad positive electrode plate 3 comprises a plurality of porous tubes 31, a core metal 32 housed within the tubes 31, a positive electrode material 33 housed within the tubes 31, and a current collector 34 connecting the plurality of core metals 32. Each tube 31 houses one core metal 32, and the plurality of core metals 32 are arranged in a line, with one end in the longitudinal direction connected by the current collector 34. With the core metals 32 housed within the tubes 31, the plurality of tubes 31 are arranged in a line perpendicular to the longitudinal direction of the tubes 31 and along the longitudinal direction of the current collector 34. The current collector 34 and one end of the plurality of tubes 31 on the current collector 34 side are covered by an upper connecting seat 35. The opening of the tube 31 on the current collector 34 side is sealed by the one end of the core metal 32 on the current collector 34 side and the upper connecting seat 35. An ear portion 34a for collecting current from the clad positive electrode plate 3 is formed at one end in the longitudinal direction of the current collector 34. The ear portion 34a protrudes outward from the upper connecting seat 35. The other ends of the multiple tubes 31 in the longitudinal direction are connected by the lower connecting seat 36.

[0119] The core metal 32 comprises a tapered portion 322 formed at one end in the longitudinal direction of the core metal 32, and a rod-shaped portion 323 connected to the tapered portion 322 and extending toward the opposite side of the tapered portion 322. The core metal 32 is housed in the tube 31 such that the tapered portion 322 is on the side of the current collection portion 34 and the rod-shaped portion 323 is on the opposite side of the current collection portion 34. The diameter of the tapered portion 322 decreases from the side of the current collection portion 34 toward the opposite side, and the rod-shaped portion 323 extends from the end of the tapered portion 322 opposite to the current collection portion 34. The core metal 32 has a columnar portion 321 with a cylindrical cross-section between the tapered portion 322 and the current collection portion 34. The area around the current collection portion 34 and the columnar portion 321 of the core metal 32 is covered by the upper connecting seat 35.

[0120] [Examples] The present invention will be described in detail below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0121] (Evaluation) Initial capacity and high-temperature and room-temperature cycle life performance will be evaluated using the following test batteries. Note that 0.2 CA (5-hour rate current I ５) refers to a current (A) that is 1 / 5 of the Ah value listed in the rated capacity. The value listed as the rated capacity is a value in Ah (ampere-hour). The unit of the current set based on the value listed as the rated capacity is A (ampere).

[0122] <Test Battery> VGD165 (Nominal voltage 2V, rated 5-hour rate capacity 165Ah, 3 positive plates / 4 negative plates) Height of positive and negative plates: 285 mm Density of electrolyte at 20°C: 1.280 g / cm³

[0123] <Cycle Life Performance> Temperature Environment: Room temperature (30°C) or high temperature (60°C) Discharge: 1.25 × 5-hour rate current I ５ , 3 hours (DOD75%) Charging: 0.9 x I ５ 5.42 hours (discharge capacity ratio 130%) every 100 cycles ５ Discharge capacity test performed at (0.2 CA) 0.2 CA discharge (I ５ ): F.V. 1.7V The device is deemed to have reached the end of its lifespan when the discharge end voltage falls below 1.7V, or when the 0.2CA discharge time falls below 4 hours.

[0124] <Initial Capacity> The 10th cycle was measured under the following conditions for charging and discharging: ５ The discharge capacity is set as the initial capacity. 1CA discharge (I ５ ): F.V. 1.7V Charging: 1 x I ５ (Discharge capacity ratio 135%)

[0125] There was no addition of oxygen-containing organic compounds (P) to the tube, no Sb source was added to the positive electrode material, and the positive electrode material density was 3.6 g / cm³. ３ The initial I of the lead-acid battery (reference battery (battery R4)) ５ The capacity retention rate is calculated as the percentage of the discharge capacity of each lead-acid battery after 200 cycles, with the initial discharge capacity set to 100%. Capacity retention rate = (Discharge capacity after 200 cycles / Initial I of the reference battery) ５ discharge capacity)×100

[0126] Lead-acid batteries R1 to R126: Clad lead-acid batteries with a nominal voltage of 2V, a rated capacity of 165Ah, three positive plates, four negative plates, and a negative plate height of 285mm are manufactured according to the following procedure.

[0127] (1) Production of the positive electrode plate Each of the 15 core metals, each with one end in the longitudinal direction integrated with the current collector equipped with lugs, is housed in 15 tubes. An upper resin joint is formed by covering the current collector and one end in the longitudinal direction of the tube on the current collector side with resin so that the lugs are exposed. The material of the core metals and current collector is a Pb-Sb alloy (Sb content 5.0 mass%), and the length of each core metal is 280.5 mm. As for the tubes, porous glass fiber tubes with a length of 286 mm and an outer diameter of 9.6 mm are used.

[0128] A positive electrode slurry prepared by kneading lead powder (containing 80% by mass of lead oxide and 20% by mass of metallic lead), red lead, water, and dilute sulfuric acid is filled into the tube through the opening at the other end in the longitudinal direction. Then, the opening at the other end of the tube is sealed with a lower joint and dried. In this way, an unformed clad positive electrode plate is produced. The width of the produced positive electrode plate is 147 mm. The mass ratio of lead powder to red lead is 9:1. At this time, the positive electrode slurry is adjusted so that the density (Dp) of the positive electrode material in a fully charged, preformed lead-acid battery is the same as that in Tables 1A to 1C.

[0129] (2) The lead powder, barium sulfate, carbon black, and sodium ligninsulfonate, which are the raw materials for making the negative electrode plate, 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 barium sulfate content in the negative electrode material of a fully charged lead-acid battery that has already been chemically processed is 1.74% by mass, the carbon black content is 0.35% by mass, and the organic shrinkage inhibitor content is 0.12% by mass. The negative electrode paste is filled into the mesh of a cast grid of a Pb-Sb alloy (Sb content 3.0% by mass), which is the negative electrode current collector, and is aged and dried to obtain an unchemically processed negative electrode plate.

[0130] (3) A microporous membrane containing polyethylene and silica particles is used as the separator. The base of the separator is 0.4 mm thick, and ribs with a height of 0.1 mm are provided only on the surface on the positive electrode side, along the vertical direction of the lead-acid battery. The total thickness of the separator is 0.5 mm. The rib width is 0.8 mm, and the rib pitch is 9.0 mm.

[0131] (4) Preparation of the electrolyte A sulfuric acid aqueous solution is prepared as the electrolyte. The density of the electrolyte after chemical conversion is 1.28 g / cm³ ３ That is the case.

[0132] (5) Manufacturing of a lead-acid battery A lead-acid battery (LA) that satisfies the various parameters shown in Table 1 is manufactured. Specifically, an electrode plate group is formed using four unformed negative electrode plates and three unformed positive electrode plates enclosed in a cylindrical separator. The tabs of the positive electrode plates and the tabs of the negative electrode plates are welded to the positive electrode strap and negative electrode strap, respectively, using the cast-on-strap (COS) method. The electrode plate group is inserted into a polypropylene battery case, electrolyte is poured in, and the batteries are reformed inside the battery case to assemble a liquid lead-acid battery with a nominal voltage of 2V and a rated 5-hour rate capacity of 165Ah as described above.

[0133] (6) Evaluation The prepared lead-acid battery is fully charged, and its cycle life performance at room temperature (30°C) or high temperature (60°C) and its initial capacity at 30°C are evaluated using the method described above. The results are shown in Tables 1A to 1C.

[0134]

[0135]

[0136]

[0137] Tables 1A to 1C show that in conventional configurations without oxygen-containing organic compounds (P), adding an Sb source to the positive electrode material improves the room-temperature cycle life, but significantly reduces the high-temperature cycle life. Furthermore, it can be seen that batteries with lower positive electrode material density show improved initial capacity, but decreased cycle life.

[0138] 《Lead-acid batteries B1-B6》 The positive electrode tube is immersed in an ethanol solution of the oxygen-containing organic compound listed in Table 2 and dried to impregnate the tube with the oxygen-containing organic compound. The ratio of the amount of oxygen-containing organic compound contained in the tube to the mass of the electrolyte (PR (mass%)) shall be 0.10 mass%. In addition, antimony trioxide (Sb) is added to the positive electrode slurry. ２ O ３The positive electrode material contains 0.10 mass% of Sb element, and is otherwise the same as described above, with a density (Dp) of 3.40 g / cm³ of the positive electrode material. ３ A positive electrode plate is fabricated. A lead-acid battery is then fabricated and evaluated in the same manner as described above, except that the obtained positive electrode plate is used.

[0139]

[0140] Table 2 shows that the initial capacity and high-temperature cycle life are significantly improved only when the tube contains an oxygen-containing organic compound (P) having the aforementioned characteristics (A) to (D).

[0141] <Oxygen-containing organic compound>

[0142] (a) POE / TDE (Polyoxyethylene Tridecyl Ether) (Oxygen-containing Organic Compound (P)) Number of carbon atoms in the terminal alkyl group = 13 Number of oxyethylene units N = 5 to 22 Number of peaks in the m / z region = 400 to 1200 = 18 Peak interval (m / z) = 20 to 25 or 40 to 50 Oxygen content (PO) = 0.309

[0143] (b) POE / STE (Polyoxyethylene cetyl ether) (Oxygen-containing organic compound (P)) Number of carbon atoms in the terminal alkyl group = 16 Number of oxyethylene units N = 6 to 33 Number of peaks in the m / z range = 400 to 1200 = 45 Peak interval (m / z) = 20 to 25 or 40 to 50 Oxygen content (PO) = 0.318

[0144] (c) POE / OLE (Polyoxyethylene Oleyl Ether) Number of carbon atoms in terminal alkylene group = 18 Number of oxyethylene units N = 5-20 Number of peaks in the m / z range = 400-1200 = 32 Peak interval (m / z) = 20-25 or 40-50 Oxygen content (PO) = 0.209

[0145] (d) PEG (polyoxyethylene glycol) Peak interval (m / z) = 44 Oxygen content (PO) = 0.371

[0146] (e) Oleic acid oxygen content (PO) = 0.113

[0147] (f) PPG (Polyoxypropylene Glycol) Peak interval (m / z) = 58 Oxygen content (PO) = 0.283

[0148] (g) PEG oleate (polyoxyethylene oleyl ester) Peak interval (m / z) = 44 Oxygen content (PO) = 0.240

[0149] (h) PEG distearate (polyoxyethylene distearate) Peak interval (m / z) = 44 Oxygen content (PO) = 0.345

[0150] (i) POE lauryl ether (polyoxyethylene laurate) Peak interval (m / z) = 22, 44 Oxygen content (PO) = 0.320

[0151] 《Lead-acid batteries C1 to C42》 The positive electrode tube is immersed in a POE / TDE ethanol solution and dried to impregnate the tube with POE / TDE. The ratio of the amount of oxygen-containing organic compound (P) contained in the tube to the mass of the electrolyte (PR (mass%)) shall be 0.03 mass%. In addition, antimony trioxide (Sb) is added to the positive electrode slurry. ２ O ３ The positive electrode material is made to contain Sb element at the concentration shown in Table 3A. Except for these points, a positive electrode plate is fabricated in the same manner as above, comprising a positive electrode material with the density shown in Table 3A. Except for using the obtained positive electrode plate, a lead-acid battery is fabricated and evaluated in the same manner as above.

[0152]

[0153] From Table 3A, when the PR (mass%) of oxygen-containing organic compounds (P) is 0.03 mass%, the positive electrode material contains 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm³. ３ In the above cases, it can be seen that the high-temperature cycle life is significantly improved.

[0154] For lead-acid batteries D1 to D42, a positive electrode plate is prepared in the same manner as above, except that the ratio of the amount of oxygen-containing organic compound contained in the tube to the mass of the electrolyte (PR (mass%)) is set to 0.10 mass%, using the positive electrode material with the density described in Table 3B. A lead-acid battery is then prepared and evaluated in the same manner as above, except that the obtained positive electrode plate is used.

[0155]

[0156] From Table 3B, when the PR (mass%) of oxygen-containing organic compounds (P) is 0.10 mass%, the positive electrode material contains 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm³. ３ In the above cases, it can be seen that the high-temperature cycle life is significantly improved.

[0157] For lead-acid batteries E1 to E42, a positive electrode plate is prepared in the same manner as above, except that the ratio of the amount of oxygen-containing organic compound contained in the tube to the mass of the electrolyte (PR (mass%)) is set to 0.50 mass%, using the positive electrode material with the density described in Table 3C. A lead-acid battery is then prepared and evaluated in the same manner as above, except that the obtained positive electrode plate is used.

[0158]

[0159] From Table 3C, when the PR (mass%) of oxygen-containing organic compounds (P) is 0.50 mass%, the positive electrode material contains 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm³. ３ In the above cases, it can be seen that the high-temperature cycle life is significantly improved.

[0160] For lead-acid batteries F1 to F42, a positive electrode plate is prepared in the same manner as above, except that the ratio of the amount of oxygen-containing organic compound contained in the tube to the mass of the electrolyte (PR (mass%)) is set to 0.60 mass%, using the positive electrode material with the density described in Table 3D. A lead-acid battery is then prepared and evaluated in the same manner as above, except that the obtained positive electrode plate is used.

[0161]

[0162] From Table 3D, when the PR (mass%) of oxygen-containing organic compounds (P) is 0.60 mass%, the positive electrode material contains 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm³. ３ In the above cases, it can be seen that the high-temperature cycle life is improved.

[0163] 《Lead-acid batteries I1-I42, J1-J42》 The positive electrode tube is immersed in an ethanol solution of an oxygen-containing organic compound and dried to impregnate the tube with the oxygen-containing organic compound. The ratio of the amount of oxygen-containing organic compound (P) contained in the tube to the mass of the electrolyte (PR (mass%)) shall be 0.10 mass%. In addition, antimony trioxide (Sb) is added to the positive electrode slurry. ２ O ３ The positive electrode material is made to contain Sb element in the proportions shown in Tables 3E and 3F, by adding ( ). Except that the oxygen-containing organic compound to be included in the tube relative to the mass of the electrolyte is POE / SE (polyoxyethylene cetyl ether) in Table 3E and POE / STE + POE / OLE in Table 3F, a positive electrode plate is prepared in the same manner as above, with the positive electrode material having the density shown in Tables 3E and 3F. A lead-acid battery is prepared and evaluated in the same manner as above, except that the obtained positive electrode plate is used.

[0164]

[0165] From Tables 3E and 3F, when the PR (mass%) of the oxygen-containing organic compound (P) is 0.10 mass%, even when the oxygen-containing organic compound (P) is POE / STE (polyoxyethylene cetyl ether) or POE / STE + POE / OLE, the positive electrode material contains 0.03 mass% or more of Sb, and the density of the positive electrode material is 3.2 g / cm³, similar to POE / TDE (polyoxyethylene tridecyl ether). ３ In the above cases, it can be seen that the high-temperature cycle life is significantly improved.

[0166] 《Lead-acid battery G1》 Instead of applying POE / TDE to the tube, POE / TDE is applied to the separator. The ratio of the amount of oxygen-containing organic compound contained in the separator to the mass of the electrolyte is set to 0.10% by mass. The Sb content in the positive electrode material is set to 0.10% by mass, and the density of the positive electrode material is set to 3.4 g / cm³. ３ This is the case. Aside from these points, a lead-acid battery will be fabricated and evaluated in the same manner as battery D15. The results are shown in Table 4.

[0167] Lead-acid battery G2: Instead of adding POE / TDE to the tube, POE / TDE is added to the negative electrode material. The POE / TDE content in the negative electrode material is set to 0.10 mass%. The Sb content in the positive electrode material is set to 0.10 mass%, and the density of the positive electrode material is set to 3.4 g / cm³. ３ This is the case. Aside from these points, a lead-acid battery will be fabricated and evaluated in the same manner as battery D15. The results are shown in Table 4.

[0168]

[0169] Table 4 shows that initial capacity and high-temperature cycle life are improved only when oxygen-containing organic compounds (P) are included in the positive electrode tube, and that sufficient effects cannot be obtained by including a predetermined amount of oxygen-containing organic compounds (P) in the separator or negative electrode material.

[0170] Lead-acid batteries H1-H4: Lead-acid batteries were manufactured and evaluated in the same manner as battery D15, except that the positive electrode current collector contained Sn at the concentrations shown in Table 5. The results are shown in Table 5.

[0171]

[0172] Table 5 shows that by including Sn in the positive electrode current collector at a predetermined concentration, the initial capacity can be improved and the high-temperature cycle life can be extended.

[0173] The lead-acid battery according to the present invention is suitable, for example, as an industrial lead-acid battery or a lead-acid battery for electric vehicles (such as forklifts), but its application is not particularly limited.

[0174] 1: Lead-acid battery 2: Negative electrode plate 3: Positive electrode plate 31: Tube 32: Core metal 321: Columnar part 322: Tapered part 323: Rod-shaped part 33: Positive electrode material 34: Current collector part 34a: Ear part of positive electrode plate 35: Upper connection seat 36: Lower connection seat 4: Separator 5a: Negative electrode strap 5b: Positive electrode strap 6a: Negative electrode column 6b: Positive electrode column 10: Battery case 11: Electrode group 12: Electrolyte

Claims

1. A lead-acid battery comprising a clad positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolyte, wherein the clad positive electrode plate comprises a plurality of porous tubes, a core metal housed within the tubes, a positive electrode material filled within the tubes, and a current collector connecting one end of the plurality of core metals arranged in a row in the longitudinal direction, wherein the positive electrode material contains 0.03% by mass or more of Sb, the density of the positive electrode material is 3.2 g / cm³ or more, the tubes contain an oxygen-containing organic compound, the LC / MS spectrum of the oxygen-containing organic compound measured with chloroform as the solvent has a plurality of peaks in the region where the m / z value is 400 or more and 2000 or less, the plurality of peaks are spaced apart with m / z values ​​of 20 or more and 25 or less, or 40 or more and 50 or less, and all oxygen atoms contained in the oxygen-containing organic compound are contained in at least one of an ether bond and a hydroxyl group. A lead-acid battery in which the ratio of the total mass of oxygen atoms contained in the oxygen-containing organic compound to the mass of the oxygen-containing organic compound is less than 0.320, and the mass of the oxygen-containing organic compound contained in the tube is 0.03% to 0.5% by mass of the mass of the electrolyte.

2. The lead-acid battery according to claim 1, wherein the density of the positive electrode material is 3.2 g / cm³ to 3.8 g / cm³.

3. The lead-acid battery according to claim 1, wherein the core metal and the current collector are made of a Pb-Sb alloy, and the Pb-Sb alloy contains 0.01% by mass to 0.1% by mass of Sn.

4. The lead-acid battery according to claim 1, wherein the positive electrode material contains 0.05% by mass to 0.4% by mass of Sb.

5. The lead-acid battery according to claim 1, wherein the mass of the oxygen-containing organic compound contained in the tube is 0.1% to 0.5% by mass of the mass of the electrolyte.

6. The lead-acid battery according to claim 1, wherein the mass of the oxygen-containing organic compound contained in the tube is 0.1% to 0.3% by mass of the mass of the electrolyte.

7. The lead-acid battery according to claim 1, wherein the height of the positive electrode plate and the negative electrode plate is 200 mm or more.

8. The lead-acid battery according to claim 1, wherein the positive electrode plate is of the clad type.

9. The lead-acid battery according to claim 1, wherein the LC / MS spectrum of the oxygen-containing organic compound measured with chloroform as a solvent has 10 or more peaks in the region where the m / z value is 400 or more and 1200 or less.

10. The lead-acid battery according to claim 1, wherein the oxygen-containing organic compound is an ether having a polyoxyethylene group and a terminal alkyl group or terminal alkenyl group.

11. The lead-acid battery according to claim 10, wherein the number of carbon atoms in the terminal alkyl group or terminal alkenyl group is 10 or more and 20 or less.

12. The lead-acid battery according to claim 10, wherein the number of carbon atoms in the terminal alkyl group or terminal alkenyl group is 13 or more and 18 or less.

13. The lead-acid battery according to claim 10, wherein the number of carbon atoms in the terminal alkyl group or terminal alkenyl group is 13 or more and 17 or less.

14. The lead-acid battery according to claim 10, wherein the number N of oxyethylene units in the polyoxyethylene group is 5 or more and 35 or less.

15. The lead-acid battery according to claim 10, wherein the number N of oxyethylene units in the polyoxyethylene group is 7 or more and 25 or less.

16. The lead-acid battery according to claim 10, wherein the number N of oxyethylene units in the polyoxyethylene group is 10 or more and 20 or less.

17. The lead-acid battery according to claim 10, wherein the oxygen-containing organic compound is at least one selected from the group consisting of polyoxyethylene oleyl ether, polyoxyethylene tridecyl ether, and polyoxyethylene cetyl ether.

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