JP2022085750A - Control valve type lead acid battery - Google Patents

Abstract

To provide a lead acid battery having a low internal resistance and a good discharge retention rate at high rate discharge.SOLUTION: A control valve type lead acid battery includes an electrode plate group 11, an electrolyte, and a battery case 10 that houses the electrode plate group and the electrolyte, the electrode plate group includes a positive electrode plate 3, a negative electrode plate 2, and an AGM separator 4 interposed between the positive electrode plate and the negative electrode plate, the pressure applied in the stacking direction of the positive electrode plate and the negative electrode plate to the electrode plate group in the electric tank is 10 kPa or more and 40 kPa or less, and the density of the AGM separator when compression force of 20 kPa is applied in the thickness direction is 0.14 g/cm3 or more and 0.20 g/cm3 or less, the negative electrode plate contains a negative electrode material, the negative electrode material contains a polymer compound, and the polymer compound has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1H-NMR spectrum measured using heavy chloroform as a solvent.SELECTED DRAWING: Figure 1

Description

The present invention relates to a control valve type lead acid battery.

Lead-acid batteries are used in various applications such as in-vehicle use and industrial use. Lead-acid batteries include a negative electrode plate, a positive electrode plate, a separator (or mat), an electrolytic solution, and the like. Each electrode plate comprises a current collector and an electrode material. Additives may be added to the constituent members of the lead-acid battery from the viewpoint of imparting various functions.

Patent Document 1 describes a group of electrode plates in which a negative electrode plate in which a negative electrode active material is filled in a negative electrode current collector and a positive electrode plate in which a positive electrode active material is filled in a positive electrode current collector are laminated via a separator. , A lead storage battery having a structure housed in an electric tank together with an electrolytic solution, wherein the negative electrode active material contains scaly graphite and sodium bisphenol A aminobenzenesulfonate represented by a predetermined chemical structural formula in the negative electrode active material. It contains a formaldehyde condensate of a salt, the molecular weight of the formaldehyde condensate of the sodium bisphenol A aminobenzene sulfonic acid salt is 15,000 to 20,000, and the sulfur content in the compound is 6 to 10% by mass. , A lead storage battery characterized in that the average primary particle size of the scaly graphite is 100 μm or more and 220 μm or less is described.

In Patent Document 2, an aqueous emulsion of silicone is impregnated into an electrode obtained by filling a support with a kneaded product of an active material in which a dispersion of a fluororesin is added and kneaded to form fluororesin fibers. A method for manufacturing an electrode for a lead storage battery, which comprises a step and a step of drying next, is described.

In Patent Document 3, a polyoxyperfluoroethylenephenylamine represented by a predetermined chemical formula is used as the shrink-proofing agent in a negative electrode plate for a lead storage battery in which a paste-type active material containing a shrinkage-proofing agent is filled in a current collector. A negative electrode plate for a lead storage battery is described, wherein the polyoxyperfluoroethylene phenylamine is contained in an amount of 0.005 to 3% by weight based on the paste-type active material.

Patent Document 4 comprises a microporous sheet containing a heavy metal adsorbent made of a rare earth compound having a high heavy metal adsorbing ability in a neutral region and a low heavy metal adsorbing ability in an acidic region. A separator for a lead storage battery, characterized in that the heavy metal adsorbent is unevenly distributed to form a layer containing the heavy metal adsorbent extending in the horizontal direction of the sheet and a layer substantially non-containing the heavy metal adsorbent. Have been described.

In Patent Document 5, in a control valve type lead-acid battery in which a group of electrode plates having a separator interposed between the positive and negative electrode plates is housed in an electric tank and an electrolytic solution is held in the electrode plate group and the separator, the separator is used. Described is a control valve type lead-acid battery, which is a mixed paper mat of glass fiber and organic fiber, and the electrolytic solution is a silica sol to which silica is added.

In Patent Document 6, a group of electrode plates including a positive electrode plate, a negative electrode plate, and a separator is a method for manufacturing a control valve type lead-acid battery arranged in an electric tank, and lead powder and lead are used as raw materials for a positive electrode active material. In the step of producing a positive electrode plate using lead-acid having a tanning rate of 20% by mass to 80% by mass, and in the electric tank so that a pressing force of 9.8 to 34.3 kPa is applied to the electrode plate group. A method for manufacturing a control valve type lead-acid battery, which comprises a step of arranging and a step of arranging the lead-acid battery, is described.

Japanese Unexamined Patent Publication No. 2013-41848 Japanese Unexamined Patent Publication No. 58-1863 Japanese Unexamined Patent Publication No. 9-147874 Japanese Unexamined Patent Publication No. 2007-31133 Japanese Unexamined Patent Publication No. 2008-204638 Japanese Unexamined Patent Publication No. 2009-124333

Liquid reduction is the main life mode of the control valve type lead acid battery (VRLA). As the liquid reduction progresses, the AGM separator contracts and the contact resistance between the electrode plate and the AGM separator (or electrolytic solution) increases. In addition, the specific gravity of the electrolytic solution increases, and the lattice corrosion of the positive electrode is likely to proceed. As a result, the internal resistance of the battery increases, and the capacity retention rate at high rate discharge decreases.

One aspect of the present invention includes a electrode plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution, and the electrode plate group includes a positive electrode plate, a negative electrode plate, and a positive electrode plate. An AGM separator interposed between the positive electrode plate and the negative electrode plate is provided, and the pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa. The density of the AGM separator when a compression force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less, and the negative electrode plate is a negative electrode material. The negative electrode material contains a polymer compound, and the polymer compound is in the range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of ¹ H-NMR spectrum measured using heavy chloroform as a solvent. It relates to a control valve type lead storage battery having a peak.

Another aspect of the present invention includes a electrode plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution, and the electrode plate group includes a positive electrode plate, a negative electrode plate, and a positive electrode. An AGM separator interposed between the plate and the negative electrode plate is provided, and the pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa. The density of the AGM separator when a compression force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less, and the negative electrode plate is a negative electrode material. The negative electrode material comprises a polymer compound, wherein the polymer compound relates to a control valve type lead storage battery having a repeating structure of an _{oxyC 2-4} alkylene unit.

Provided is a control valve type lead acid battery having an excellent capacity retention rate at high rate discharge.

It is sectional drawing which shows typically the structure of the control valve type lead-acid battery which concerns on one Embodiment.

The control valve type lead-acid battery (VRLA) according to the embodiment of the present invention includes a plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution. The electrode plate group includes a positive electrode plate, a negative electrode plate, and an AGM separator interposed between the positive electrode plate and the negative electrode plate. The AGM (Absorbed Glass Mat) separator is a non-woven fabric containing glass fiber.

The negative electrode plate contains a negative electrode material. The positive electrode plate contains a positive electrode material. Each electrode material of the negative electrode material and the positive electrode material is usually held in the current collector. The electrode material is a plate from which the current collector is removed. Members such as mats and pacing papers may be attached to the electrode plate. Since such a member (also referred to as a sticking member) is used integrally with the plate, it is included in the plate. When the electrode plate includes a sticking member (mat, pacing paper, etc.), the electrode material excludes the current collector and the sticking member.

The negative electrode material contains a polymer compound. The polymer compound has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent. Alternatively, the polymer compound may have a repeating structure of _{oxyC 2-4} alkylene units. In the above 1H-NMR spectrum, the peak appearing in the chemical shift range of 3.2 ppm or more and 3.8 ppm or less is derived from the oxyC _2-4 alkylene unit.

By including the polymer compound in the negative electrode material, it is possible to suppress the progress of liquid reduction, which is the main life mode of VRLA. It is considered that the reason why the liquid decrease can be suppressed is as follows. First, the polymer compound tends to have a linear structure, and the lead surface in the negative electrode electrode material is thinly and widely covered with the polymer compound. Since the polymer compound contained in the negative electrode electrode material is present in the vicinity of lead, it is considered that the _{oxyC 2-4} alkylene unit exhibits a high adsorptive action on lead. By covering a wide area of the lead surface with the polymer compound, the hydrogen overvoltage rises, and hydrogen generation is less likely to occur during overcharging. Therefore, the liquid reduction can be reduced. As described above, in order to effectively exert the effect of the polymer compound, the negative electrode electrode material contains the polymer compound regardless of whether or not the lead storage battery component other than the negative electrode material contains the polymer compound. It is important to be.

On the other hand, a part of the polymer compound adsorbed on the lead surface is eluted into the electrolytic solution due to the volume change of the negative electrode material due to charge and discharge and the external force due to the generation of hydrogen gas. The polymer compound eluted in the electrolytic solution moves to the positive electrode plate and is oxidatively decomposed. Therefore, the self-discharge of the positive electrode plate is promoted, and the charging current at the time of float charging increases. As a result, corrosion of the positive electrode plate (particularly the positive electrode current collector) progresses, the internal resistance of the battery increases, and the high-rate discharge capacity decreases. That is, it was found that although the liquid reduction can be suppressed by including the polymer compound in the negative electrode material, the positive electrode plate derived from the polymer compound is corroded, and eventually the capacity retention rate at high rate discharge is lowered. did.

On the other hand, the pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate (hereinafter, also referred to as “tension pressure”) is set to 10 kPa or more and 40 kPa or less, and When the density of the AGM separator (hereinafter, also referred to as "20 kPa density") when a compressive force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less, the negative electrode. Even when the electrode material contains a polymer compound, the decrease in the capacity retention rate due to high-rate discharge is suppressed.

First, it is considered that by setting the tension pressure on the electrode plates in the battery case within the above range, the adsorption force of the polymer compound to the negative electrode electrode material is improved, and the polymer compound is less likely to elute into the electrolytic solution. Be done. Secondly, by setting the above range, the fluidity of the electrolytic solution is suppressed, the movement of the polymer compound eluted in the electrolytic solution to the positive electrode plate is suppressed, and the polymer compound is less likely to be oxidatively decomposed by the positive electrode plate. It is considered that the self-discharge of the positive electrode is suppressed. Thirdly, it is considered that the polymer compound is less likely to elute from the negative electrode plate, so that the effect of suppressing the liquid reduction is enhanced, the specific gravity of the electrolytic solution is less likely to increase, and the corrosion of the positive electrode plate is less likely to proceed. Be done.

When the tension pressure is 10 kPa or more, it is considered that the elution of the polymer compound into the electrolytic solution is less likely to proceed and the effect of suppressing the liquid reduction is greater than when the tension pressure is less than 10 kPa. This suppresses an increase in contact resistance between the electrode plate and the AGM separator, especially in VRLA. Further, when the tension pressure is 10 kPa or more, the polymer compound is less likely to move to the positive electrode plate, is less likely to be oxidatively decomposed, and the progress of self-discharge of the positive electrode plate is limited as compared with the case where the tension pressure is less than 10 kPa. Therefore, the charging current during float charging is unlikely to increase, the progress of corrosion of the positive electrode plate (particularly the positive electrode current collector) and the increase in the internal resistance of the battery are suppressed, and the capacity retention rate in high-rate discharge is improved. Further, when the tension pressure is 40 kPa or less, a free electrolytic solution that is not absorbed by the AGM separator is unlikely to be generated, and the amount of liquid reduction is suppressed. On the other hand, when the tension pressure is less than 10 kPa, the elution of the polymer compound into the electrolytic solution is more likely to proceed and the effect of suppressing the liquid reduction is more likely to be reduced as compared with the case where the tension pressure is 10 kPa or more. Especially in VRLA, the contact resistance between the electrode plate and the AGM separator tends to increase. Further, when the tension pressure is less than 10 kPa, the polymer compound moves to the positive electrode plate and is easily oxidatively decomposed as compared with the case where the tension pressure is 10 kPa or more, and the self-discharge of the positive electrode plate is likely to proceed. As a result, the charging current during float charging increases, the corrosion of the positive electrode plate (particularly the positive electrode current collector) progresses, the internal resistance of the battery increases, and the capacity retention rate in high-rate discharge decreases. When the tension pressure exceeds 40 kPa, the amount of liquid reduction starts to increase slightly, which is considered to be because the amount of free electrolytic solution that is not absorbed by the AGM separator increases.

However, in order to suppress the movement of the eluted polymer compound to the positive electrode plate, it is necessary to set the 20 kPa density of the AGM separator within the above range. When the density of the AGM separator is within the above range, the physical obstacles caused by the glass fibers constituting the AGM separator become large, the fluidity of the electrolytic solution decreases, and the particles move from the surface of the negative electrode plate to the surface of the positive electrode plate via the AGM separator. The flow path of the electrolytic solution becomes long. Further, when the 20 kPa density of the AGM separator is in the above range, the distance between the glass fibers becomes short and the surface tension becomes large. As a result, the electrolytic solution existing between the glass fibers tends to stay in place. Therefore, it is considered that the polymer compound eluted in the electrolytic solution is more difficult to reach the positive electrode plate.

When the 20 kPa density of the AGM separator is 0.14 g / cm ³ or more, the polymer compound is less likely to move to the positive electrode plate and is less likely to be oxidatively decomposed because there is sufficient physical damage due to the glass fiber. Therefore, the self-discharge of the positive electrode is suppressed, and the capacity retention rate in high-rate discharge is improved. Further, when the 20 kPa density of the AGM separator is 0.20 g / cm ³ or less, the free electrolytic solution is reduced, so that it becomes difficult to reduce the solution, the increase in the specific gravity of the electrolytic solution is suppressed, and the corrosion of the positive electrode plate and the battery are suppressed. The increase in internal resistance is also suppressed. As a result, the capacity retention rate in high-rate discharge is improved. On the other hand, if the 20 kPa density of the AGM separator is less than 0.14 g / cm ³ , the physical damage caused by the glass fiber is not sufficient, and the polymer compound moves to the positive electrode plate and is easily oxidatively decomposed. Therefore, self-discharge of the positive electrode progresses, and the capacity retention rate in high-rate discharge decreases. Further, when the 20 kPa density of the AGM separator exceeds 0.20 g / cm ³ , the amount of free electrolytic solution increases, so that the amount of reduced liquid decreases, the specific gravity of the electrolytic solution increases, and the corrosion of the positive electrode plate progresses. Therefore, the internal resistance of the battery increases, and the capacity retention rate at high rate discharge decreases.

In the present specification, the tension on the electrode plate group in the battery case, the 20 kPa density of the AGM separator, the content of the organic fiber in the AGM separator, and the content of the polymer compound in the negative electrode electrode material are respectively the lead in a fully charged state. It is required for the electrode plate group, the AGM separator and the negative electrode plate taken out from the storage battery.

<Fully charged state>
The fully charged state of the control valve type lead-acid battery is a current (A) that is 0.2 times the value (value with Ah as the unit) described in the rated capacity in an air tank at 25 ° C ± 2 ° C. When constant current and constant voltage charging of .23V / cell is performed and the charging current during constant voltage charging becomes 0.005 times the value (A) described in the rated capacity (value with Ah as the unit). It is in a state where charging has been completed. A fully charged lead-acid battery is a fully charged lead-acid battery. The lead-acid battery may be fully charged after the chemical conversion, immediately after the chemical conversion, or after a lapse of time from the chemical conversion (for example, after the chemical conversion, the lead-acid battery in use (preferably at the initial stage of use) is fully charged. May be). An initial use battery is a battery that has not been used for a long time and has hardly deteriorated.

<Tension>
The tension on the electrode plates in the battery case can be measured by the following method. First, the electrode plates taken out from the fully charged lead-acid battery are sandwiched between a pair of resin plates from both sides in the stacking direction of the positive electrode plate and the negative electrode plate while still containing the electrolytic solution. Next, the electrode plate group is compressed to the dimension D in the stacking direction of the cell chamber in the electric tank containing the electrode plate group, and the pressure applied to the electrode plate group at that time is used as a tension pressure sensor. Measure with.

<Extreme distance G>
In the electrode plate group compressed in the stacking direction to the dimension D when measuring the tension pressure, the distance between the positive electrode plate and the negative electrode plate (hereinafter referred to as the electrode distance G) is, for example, 1.0. It may be mm or more, 1.5 mm or more, 2.0 mm or more, or 2.5 mm or more. However, the distance G between the poles is preferably 2.5 mm or less from the viewpoint of suppressing the internal resistance of the battery. For the distance between the poles, the thickness of the positive electrode plate, the thickness of the negative electrode plate, and the thickness of the AGM separator contained in the compressed electrode plate group are measured at the centers in the respective height directions, and the thickness and the number of the plates and the number of the AGM separators are measured. It can be calculated from the dimension D in the stacking direction of the cell chamber.

<20 kPa density>
The 20 kPa density of the AGM separator can be measured by the following method based on 7.2.3 of SBA S 0406: 2017. First, the thickness of the AGM separator is measured. Specifically, the AGM separator taken out from the fully charged lead-acid battery is washed with water and dried. After washing with water and drying, the AGM separator is cut into a size of 10 cm × 10 cm. Ten AGM separators having a size of 10 cm × 10 cm are stacked on a flat surface of a resin plate having flat surfaces on both sides, and the resin plate is further stacked on the AGM separator. Next, a weight of 20 kg is placed on the resin plate, and a load of 20 kg / dm ² is applied. The total thickness of 10 AGM separators is measured 30 seconds after the weight is placed. The thickness per AGM separator is calculated as 1/10 of the total thickness of 10 AGM separators. Next, the mass of the AGM separator is measured. Specifically, the mass of each of the 10 10 cm × 10 cm size AGM separators produced above is measured one by one, and the average mass is obtained. Then, from the thickness t (cm) per AGM separator obtained above and the average mass W (g) of the AGM separator, the 20 kPa density (D) is calculated by the formula: D = W / (10 × 10 × t). ).

The thickness t of the AGM separator obtained above may be, for example, 0.15 cm (1.5 mm) or more, or 0.20 cm (2.0 mm) or more, from the viewpoint of absorbing a sufficient electrolytic solution. It may be 0.25 cm (2.5 mm) or more. However, the thickness t of the AGM separator is preferably 0.30 cm (3.0) mm or less from the viewpoint of suppressing the internal resistance of the battery. The thickness t of the AGM separator is appropriately selected according to the distance between poles G, but is preferably larger than the distance between poles G. Specifically, it is desirable that the t / G ratio satisfies 1.05 ≦ t / G ≦ 1.4, and 1.1 ≦ t / G ≦ 1.3 may be satisfied.

When the lead-acid battery has two or more plate groups, at least one plate group may satisfy the above conditions. However, it is preferable that 50% or more (more preferably 80% or more or 90% or more) of the number of electrode plates contained in the lead storage battery satisfies the above conditions. Among the electrode plate groups contained in the lead storage battery, the ratio of the electrode plate group satisfying the above conditions is 100% or less. It is preferable that all of the electrode plates included in the lead-acid battery satisfy the above conditions.

Hereinafter, the lead storage battery according to the embodiment of the present invention will be described for each of the main constituent requirements, but the present invention is not limited to the following embodiments.

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

The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group. The formation produces spongy lead.

(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 processing and punching processing. It is preferable to use a grid-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

The lead alloy used for the negative electrode current collector may be any of Pb—Sb based alloy, Pb—Ca based alloy, and Pb—Ca—Sn based alloy. These leads or lead alloys may further contain, as an additive element, at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like. The negative electrode current collector may include 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 selvage portion of the negative electrode current collector. The surface layer of the selvage portion may contain Sn or a Sn alloy.

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

(Polymer compound)
The polymer compound satisfies at least one of the following conditions (i) and (ii).
Condition (i)
The polymer compound has a peak in the range of 3.2 ppm or more and 3.8 ppm or less in the chemical shift of the 1H-NMR spectrum measured using deuterated chloroform as a solvent.
Condition (ii)
The polymer compound comprises a repeating structure of _{oxyC 2-4} alkylene units. The oxy-C _2-4 alkylene unit is a unit represented by -O-R1- (R1 represents a C _2-4 alkylene group).

In condition (i), the peak of 3.2 ppm or more and 3.8 ppm or less is derived from the oxyC _2-4 alkylene unit. That is, the polymer compound satisfying the condition (ii) is also a polymer compound satisfying the condition (i). However, the polymer compound satisfying the condition (i) may contain a repeating structure of a monomer unit other than the _{oxyC 2-4} alkylene unit, and may have a certain molecular weight. The polymer compound satisfying the above (i) or (ii) may have a number average molecular weight (Mn) of, for example, 300 or more.

The polymer compound may contain an oxygen atom attached to a terminal group and an -CH ₂ -group and / or -CH <group attached to the oxygen atom. ¹ In the H-NMR spectrum, the integrated value of the peak of 3.2 ppm to 3.8 ppm, the integrated value of this peak, the integrated value of the peak of the _-CH2 -group hydrogen atom bonded to the oxygen atom, and the oxygen atom. The ratio to the total of the integrated value of the peak of the hydrogen atom of -CH <group bonded to is, for example, 50% or more, 80% or more, 85% or more, or 90% or more. Such polymer compounds contain a large amount of _{oxyC 2-4} alkylene unit in the molecule. Therefore, it is considered that the polymer compound is more likely to have a linear structure and is easier to cover the lead surface thinly. Therefore, the liquid reduction can be reduced more effectively. Further, since the lead surface is thinly covered, the charge acceptability is less likely to decrease and lead sulfate is less likely to accumulate, so that the increase in resistance during discharge is suppressed. Therefore, it becomes easy to secure the capacity retention rate in high-rate discharge. For example, if the polymer compound has a -OH group at the end and has a -CH _2- group or -CH <group bonded to the oxygen atom of this -OH group, the -CH _2- group or -CH 2- group in the 1H-NMR spectrum. The peak of the hydrogen atom of the -CH <group has a chemical shift in the range of more than 3.8 ppm and 4.0 ppm or less.

The polymer compound preferably contains a repeating structure of _{oxyC 2-4} alkylene units. When a polymer compound containing a repeating structure of an _{oxyC 2-4} alkylene unit is used, it is considered that the polymer compound is more easily adsorbed to lead and easily has a linear structure, so that the lead surface can be easily covered thinly. The repeating structure may contain one type of oxyC _{2-4 alkylene unit, or may contain two or more types of oxy C 2-4 alkylene} unit. Polymer compounds having a repeating structure of _{oxyC 2-4} alkylene units also include those classified as surfactants (eg, nonionic surfactants).

The oxyC _2-4 alkylene unit includes an oxyethylene unit, an oxypropylene unit, an oxytrimethylene unit, an oxy2-methyl-1,3-propylene unit, an oxy1,4-butylene unit, and an oxy1,3-butylene unit. And so on. The polymer compound may have one kind of such oxyC _2-4 alkylene unit, or may have two or more kinds.

The oxyC _2-4 alkylene unit may be, for example, an oxypropylene unit (-O-CH (-CH ₃ ) -CH _2- ). That is, the polymer compound may contain a repeating structure of oxypropylene units. Such polymer compounds have high adsorptivity to lead, but do not adhere excessively to the lead surface. Therefore, the liquid reduction can be effectively reduced, the charge acceptability is less likely to decrease, and lead sulfate is less likely to accumulate, so that the increase in resistance during discharge is likely to be suppressed.

The oxyC _2-4 alkylene unit may be, for example, an oxyethylene unit (-O-CH ₂ -CH _2- ). That is, the polymer compound may contain a repeating structure of oxyethylene units. Since the repeating structure of the oxyethylene unit has high hydrophilicity, it can be selectively adsorbed to lead. Therefore, it becomes easy to control the adsorptivity of the polymer compound to lead.

The polymer compound is at least selected from the group consisting of a hydroxy compound having a repeating structure of an _{oxyC 2-4} alkylene unit (hereinafter, also referred to as hydroxy compound C), an etherified product of the hydroxy compound C, and an esterified product of the hydroxy compound C. It may contain one kind.

Here, the hydroxy compound C is selected from the group consisting of a poly C _2-4 alkylene glycol, a copolymer containing a repeating structure of an oxy C _2-4 alkylene unit, and a poly C _2-4 alkylene oxide adduct of a polyol. It may be at least one kind. When such a polymer compound is used, liquid reduction can be suppressed more effectively.

Examples of the copolymer containing the repeating structure of the oxy C _2-4 alkylene unit include a copolymer containing different oxy C _2-4 alkylene units, a poly C _2-4 alkylene glycol alkyl ether, and a carboxylic acid poly C _2-4 . Examples thereof include alkylene glycol esters. The copolymer may be a block copolymer.

Examples of the polyol constituting the poly C _2-4 alkylene oxide adduct of the polyol include an aliphatic polyol, an alicyclic polyol, an aromatic polyol, and a heterocyclic polyol. Aliphatic polyols, alicyclic polyols (for example, polyhydroxycyclohexane, polyhydroxynorbornane, etc.) and the like are preferable, and aliphatic polyols are particularly preferable because the polymer compound is thin and easily spreads on the lead surface. Examples of the aliphatic polyol include an aliphatic diol, a polyol having a triol or higher (for example, glycerin, trimethylolpropane, pentaerythritol, sugar or a sugar alcohol, etc.). Examples of the aliphatic diol include alkylene glycols having 5 or more carbon atoms. The alkylene glycol may be, for example, C _5-14 alkylene glycol or C _5-10 alkylene glycol. Examples of the sugar or sugar alcohol include sucrose, erythritol, xylitol, mannitol, sorbitol and the like. The sugar or sugar alcohol may have either a chain structure or a cyclic structure.

In the polyalkylene oxide adduct of the polyol, the alkylene oxide corresponds to the _{oxyC 2-4} alkylene unit of the polymer compound and comprises at least C _2-4 alkylene oxide. From the viewpoint that the polymer compound tends to have a linear structure, the polyol is preferably a diol.

In the etherified product of hydroxy compound C, -OH groups (-OH groups composed of a hydrogen atom of the terminal group and an oxygen atom bonded to this hydrogen atom) at least a part of the terminal of hydroxy compound C are etherified. -Has an OR2 group (in the formula, R2 is an organic group). Of the ends of the polymer compound, some ends may be etherified, or all ends may be etherified. For example, one end of the main chain of the linear polymer compound may be a —OH group and the other end may be a —OR2 group.

The esterified product of hydroxy compound C has an —OC (= O) -R3 group in which the —OH group at at least a part of the terminal of hydroxy compound C is esterified (in the formula, R3 is an organic group. ). Of the ends of the polymer compound, some ends may be esterified or all ends may be esterified. For example, one end of the main chain of the linear polymer compound may be an —OH group and the other end may be an —OC (= O) -R3 group.

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

Examples of the aromatic hydrocarbon group include an aromatic hydrocarbon group having 6 or more and 24 or less carbon atoms. The number of carbon atoms of the aromatic hydrocarbon group may be 20 or less, and may be 14 or less or 12 or less. Examples of the aromatic hydrocarbon group include an aryl group and a bisaryl group. Examples of the aryl group include a phenyl group and a naphthyl group. Examples of the bisaryl group include a monovalent group corresponding to bisarene. Examples of the bisarene include biphenyl and bisarylalkane (for example, _bisC 6-10aryl C _1-4 alkane (for example, 2,2-bisphenylpropane)).

Examples of the alicyclic hydrocarbon group include an alicyclic hydrocarbon group having 16 or less carbon atoms. The alicyclic hydrocarbon group may be a crosslinked cyclic hydrocarbon group. The alicyclic hydrocarbon group may have 10 or less or 8 or less carbon atoms. The alicyclic hydrocarbon group has, for example, 5 or more carbon atoms, and may be 6 or more carbon atoms.

Examples of the alicyclic hydrocarbon group include a cycloalkyl group (cyclopentyl group, cyclohexyl group, cyclooctyl group, etc.), a cycloalkenyl group (cyclohexenyl group, cyclooctenyl group, etc.) and the like. The alicyclic hydrocarbon group also includes hydrogenated additives of aromatic hydrocarbon groups.

Of the hydrocarbon groups, an aliphatic hydrocarbon group is preferable from the viewpoint that the polymer compound is thin and easily adheres to the lead surface. Aliphatic hydrocarbon groups may be saturated or unsaturated. Examples of the aliphatic hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, a dienyl group having two carbon-carbon double bonds, and a trienyl group having three carbon-carbon double bonds. The aliphatic hydrocarbon group may be linear or branched.

The aliphatic hydrocarbon group may have, for example, 30 or less, 26 or less or 22 or less, 20 or less or 16 or less, 14 or less or 10 or less. It may be 8 or less or 6 or less. The lower limit of the number of carbon atoms is 1 or more for an alkyl group, 2 or more for an alkenyl group and an alkynyl group, 3 or more for a dienyl group, and 4 or more for a trienyl group, depending on the type of the aliphatic hydrocarbon group. Alkyl groups and alkenyl groups are particularly preferable because the polymer compound is thin and easily adheres to the lead surface.

Specific examples of the alkyl group include methyl, ethyl, n-propyl, i-propyl, n-butyl, i-butyl, s-butyl, t-butyl, n-pentyl, neopentyl, i-pentyl, and s-pentyl. 3-Pentyl, t-Pentyl, n-hexyl, 2-ethylhexyl, n-octyl, n-nonyl, n-decyl, i-decyl, undecyl, lauryl (dodecyl), tridecyl, myristyl, pentadecyl, cetyl, heptadecyl, stearyl. , Ikosil, Henikosil, Behenil and the like.

Specific examples of the alkenyl group include vinyl, 1-propenyl, allyl, cis-9-heptadecene-1-yl, palmitrail, oleyl and the like. The alkenyl group may be, for example, a C _2-30 alkenyl group or a C _2-26 alkenyl group, a C _2-22 alkenyl group or a C _2-20 alkenyl group, or a C _10-20 alkenyl group.

Among the polymer compounds, at least one selected from the group consisting of an etherified product of hydroxy compound C and an esterified product of hydroxy compound C is preferable, and these polymer compounds have a repeating structure of an oxypropylene unit or a repeating structure of an oxyethylene unit. It is preferable to have.

The polymer compound may have one or more hydrophobic groups. Examples of the hydrophobic group include aromatic hydrocarbon groups, alicyclic hydrocarbon groups, long-chain aliphatic hydrocarbon groups and the like among the hydrocarbon groups exemplified as the organic group R2 or R3. At least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The action of such hydrophobic groups suppresses excessive coating of the polymer compound on the lead surface. By the balance between the hydrophobic group and the hydrophilic group, it is possible to control the balance between the suppression of liquid reduction and the resistance at the time of discharge.

Examples of the long-chain aliphatic hydrocarbon group include those having 8 or more carbon atoms among alkyl groups and alkenyl groups, preferably 12 or more, and more preferably 16 or more. Polymer compounds with long-chain aliphatic hydrocarbon groups are less likely to cause excessive adsorption to lead, are less likely to reduce charge acceptability, and are less likely to accumulate lead sulfate, so they have the effect of suppressing an increase in resistance during discharge. It will be further enhanced. At least one of the hydrophobic groups may be a long-chain aliphatic hydrocarbon group. The carbon number of the long-chain aliphatic hydrocarbon group may be 30 or less, 26 or less, or 22 or less.

A polymer compound having a hydrophilic group and a hydrophobic group corresponds to a nonionic surfactant. The hydrophilic group may have a repeating structure of oxyethylene units. The repeating structure of the oxyethylene unit has high hydrophilicity. The balance between the hydrophobic group and the repeating structure of the oxyethylene unit makes it possible to suppress excessive coverage of the lead surface while selectively adsorbing to lead. Examples of the polymer compound corresponding to such a nonionic surfactant include a polyoxypropylene-polyoxyethylene block copolymer, an etherified product of a hydroxy compound having a repeating structure of an oxyethylene unit, and a repeating structure of an oxyethylene unit. Examples thereof include esterified products of hydroxy compounds. These can ensure high adsorptivity to lead even at a relatively low molecular weight (for example, Mn of 300 or more or 400 or more and 1000 or less). In polyoxypropylene-polyoxyethylene block copolymers and the like, the repeating structure of the oxyethylene unit corresponds to a hydrophilic group, and the repeating structure of the oxypropylene unit corresponds to a hydrophobic group.

Examples of the polymer compound corresponding to the nonionic surfactant include an etherified product of polyethylene glycol (alkyl ether, etc.), an esterified product of polyethylene glycol (carboxylic acid ester, etc.), and an etherified product of the polyethylene oxide adduct of the above polyol (alkyl ether, etc.). An esterified product (carboxylic acid ester or the like) of the polyethylene oxide adduct of the above-mentioned polyol may be used. More specific examples 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, and polyoxy. Examples thereof include, but are not limited to, ethylene lauryl ether, polyoxyethylene tetradecyl ether, and polyoxyethylene cetyl ether.

The HLB of the polymer compound classified as a surfactant is preferably 4 or more, and more preferably 4.3 or more, in that it is easy to further reduce the decrease in the electrolytic solution. From the viewpoint of suppressing an increase in resistance during discharge, the HLB of the polymer compound is preferably 18 or less, more preferably 10 or less or 9 or less, and even more preferably 8.5 or less.

It is also preferable that the repeating structure of Oxy C _2-4 alkylene contains at least the repeating structure of the oxypropylene unit. Polymer compounds containing oxypropylene units have peaks from -CH <and -CH _2- of the oxypropylene units in the range of 3.2 ppm to 3.8 ppm in the chemical shift of the 1H-NMR spectrum. Since the electron densities around the nuclei of hydrogen atoms in these groups are different, the peaks are split. Such a polymer compound has peaks in the chemical shift of ¹ H-NMR spectrum, for example, in the range of 3.2 ppm or more and 3.42 ppm or less, and in the range of 3.42 ppm or more and 3.8 ppm or less. Peaks in the range of 3.2 ppm or more and 3.42 ppm or less are derived from -CH _2- , and peaks in the range of more than 3.42 ppm and 3.8 ppm or less are derived from -CH <and -CH _2- .

Examples of the polymer compound containing the repeating structure of the oxypropylene unit include polypropylene glycol, a copolymer containing the repeating structure of the oxypropylene unit, a polypropylene oxide adduct of the above-mentioned polyol, an etherified product or an esterified product thereof. Examples of the copolymer include an oxypropylene-oxyalkylene copolymer (however, the oxyalkylene is C _2-4 alkylene other than oxypropylene). Examples of the oxypropylene-oxyalkylene copolymer include an oxypropylene-oxyethylene copolymer and an oxypropylene-oxytrimethylene copolymer. The oxypropylene-oxyalkylene copolymer may be referred to as a polyoxypropylene-polyoxyalkylene copolymer (for example, a polyoxypropylene-polyoxyethylene copolymer). The oxypropylene-oxyalkylene copolymer may be a block copolymer (for example, a polyoxypropylene-polyoxyethylene block copolymer). Examples of the etherified product include polypropylene glycol alkyl ether, alkyl ether of an oxypropylene-oxyalkylene copolymer (alkyl ether of a polyoxypropylene-polyoxyethylene copolymer, etc.) and the like. Examples of the esterified product include a polypropylene glycol ester of a carboxylic acid and a carboxylic acid ester of an oxypropylene-oxyalkylene copolymer (such as a carboxylic acid ester of a polyoxypropylene-polyoxyethylene copolymer).

Examples of the polymer compound containing the repeating structure of the oxypropylene unit include polypropylene glycol, polyoxypropylene-polyoxyethylene copolymer (polyoxypropylene-polyoxyethylene block copolymer, etc.), and polyoxyethylene-polyoxypropylene. Alkyl ether (such as alkyl ether (such as butyl ether) in which R2 is an alkyl having 10 or less carbon atoms (or 8 or less or 6 or less)), polypropylene glycol carboxylate (R3 is 10 or less carbon atoms (or 8 or less or 6 or less)). ), Polypropylene glycol carboxylate (polypropylene glycol acetate, etc.), etc.), polypropylene oxide adducts of triol or higher polyols (polypropylene oxide adducts of glycerin, etc.), but are not limited thereto.

In the polymer compound, the proportion of the oxypropylene unit is, for example, 5 mol% or more, and may be 10 mol% or more or 20 mol% or more. The proportion of the oxypropylene unit is, for example, 100 mol% or less. In the above copolymer, the proportion of the oxypropylene unit may be 90 mol% or less, 75 mol% or less, or 60 mol% or less.

From the viewpoint of suppressing an increase in resistance during discharge, the content of the polymer compound in the negative electrode electrode material is preferably 500 ppm or less on a mass basis. Further, from the viewpoint of further suppressing the liquid reduction, the content of the polymer compound in the negative electrode electrode material is preferably 30 ppm or more on a mass basis.

The content (mass basis) of the polymer compound in the negative electrode material is 30 ppm or more and 500 ppm or less, 30 ppm or more and 400 ppm or less, 30 ppm or more and 200 ppm or less, 50 ppm or more and 500 ppm or less, 50 ppm or more and 400 ppm or less, 50 ppm or more and 200 ppm or less, 80 ppm or more and 500 ppm or less. , 80 ppm or more and 400 ppm or less, or 80 ppm or more and 200 ppm or less.

The polymer compound preferably contains a compound having a number average molecular weight (Mn) of 10,000 or less. In this case, the thickness of the film of the polymer compound covering the surfaces of lead and lead sulfate can be further reduced. Therefore, the charge acceptability is less likely to decrease and lead sulfate is less likely to accumulate, so that the increase in resistance during discharge is further suppressed.

The polymer compound preferably contains a polymer compound having Mn of 500 or more. In this case, higher adsorptivity to lead can be ensured, and the lead surface can be easily covered with the polymer compound. The amount of overcharged electricity can be further reduced. Therefore, the effect of suppressing the progress of liquid reduction is enhanced.

The negative electrode material may contain one kind of polymer compound, or may contain two or more kinds. Further, as the negative electrode electrode material, two or more kinds of polymer compounds having different Mns may be used. That is, the molecular weight distribution of the polymer compound may have a plurality of Mn peaks.

The Mn of the polymer compound is 500 or more (or 1000 or more) 10000 or less, 500 or more (or 1000 or more) 5000 or less, 500 or more (or 1000 or more) 4000 or less, 500 or more (or 1000 or more) 3000 or less, or 500 or more. It may be 2500 or less (or 1000 or more).

<Number average molecular weight>
The number average molecular weight (Mn) is determined by gel permeation chromatography (GPC). The standard substance used to determine Mn is polyethylene glycol.

(Organic shrinkage agent)
The organic shrink-proofing agent refers to an organic compound among compounds having a function of suppressing the shrinkage of lead, which is a negative electrode active material, when the lead storage battery is repeatedly charged and discharged. As the organic shrinkage proofing agent, for example, at least one selected from the group consisting of a lignin compound and a synthetic organic shrinkage proofing agent may be used.

Examples of the lignin compound include lignin and lignin derivatives. Examples of the lignin derivative include lignin sulfonic acid or a salt thereof (alkali metal salt (sodium salt, etc.), etc.).

The synthetic organic shrinkage proofing agent used in a lead storage battery is usually an organic condensate (hereinafter, simply referred to as a condensate). The condensate is a synthetic product that can be obtained by utilizing a condensation reaction. The condensate may contain a unit of an aromatic compound (hereinafter, also referred to as an aromatic compound unit). The aromatic compound unit refers to a unit derived from an aromatic compound incorporated in a condensate. That is, the aromatic compound unit is a residue of the aromatic compound. The condensate may contain one unit of the aromatic compound, or may contain two or more units.

Examples of the condensate include a condensate made of an aldehyde compound of an aromatic compound. Such a condensate can be synthesized by reacting an aromatic compound with an aldehyde compound. Here, the sulfur element is contained by carrying out the reaction between the aromatic compound and the aldehyde compound in the presence of a sulfite, or by using an aromatic compound containing a sulfur element (for example, bisphenol S) as the aromatic compound. A condensate can be obtained. For example, the sulfur element content in the condensate can be adjusted by adjusting at least one of the amount of sulfites and the amount of aromatic compounds containing sulfur elements. When other raw materials are used, this method may be followed. The aromatic compound to be condensed to obtain a condensate may be one kind or two or more kinds. The aldehyde compound may be an aldehyde (for example, formaldehyde), a condensate (or a polymer) of an aldehyde, or the like. Examples of the aldehyde condensate (or polymer) include paraformaldehyde, trioxane, tetraoxymethylene and the like. As the aldehyde compound, one kind may be used alone, or two or more kinds may be used in combination. Formaldehyde is preferable from the viewpoint of high reactivity with aromatic compounds.

The aromatic compound may have a sulfur-containing group. That is, the condensate may be an organic polymer containing a plurality of aromatic rings in the molecule and also containing a sulfur element as a sulfur-containing group. The sulfur-containing group may be directly bonded to the aromatic ring of the aromatic compound, or may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group, which is a stable form, is preferable. The sulfonic acid group may be present in acid form or may be present in salt form such as Na salt.

Examples of the aromatic ring contained in the aromatic compound include a benzene ring and a naphthalene ring. When the aromatic compound has a plurality of aromatic rings, the plurality of aromatic rings may be directly bonded or linked by a linking group (for example, an alkylene group (including an alkylidene group), a sulfone group) or the like. Examples of such a structure include a bisarene structure (biphenyl, bisphenylalkane, bisphenylsulfone, etc.).

Examples of the aromatic compound include the above-mentioned aromatic ring and a compound having a functional group (hydroxy group, amino group, etc.). The functional group may be directly bonded to the aromatic ring, or may be bonded as an alkyl chain having a functional group. The hydroxy group also includes a salt of the hydroxy group (-OMe). Amino groups also include salts of amino groups (salts with anions). Examples of Me include alkali metals (Li, K, Na, etc.), Group 2 metals of the periodic table (Ca, Mg, etc.) and the like. The aromatic compound may have a sulfur-containing group and a substituent other than the above functional groups (for example, an alkyl group and an alkoxy group) in the aromatic ring.

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

Examples of the bis-alene compound include a bisphenol compound, a hydroxybiphenyl compound, and a bis-alene compound having an amino group (a bisarylalkane compound having an amino group, a bisarylsulfone compound having an amino group, a biphenyl compound having an amino group, and the like). Of these, bisphenol compounds are preferable.

As the bisphenol compound, bisphenol A, bisphenol S, bisphenol F and the like are preferable. For example, the bisphenol compound may contain at least one selected from the group consisting of bisphenol A and bisphenol S. By using bisphenol A or bisphenol S, an excellent shrinkage-proofing effect on the negative electrode material can be obtained.

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

As the monocyclic aromatic compound, a hydroxymonoarene compound, an aminomonoarene compound and the like are preferable. Of these, hydroxymonoarene compounds are preferable.

Examples of the hydroxymonoarene compound include hydroxynaphthalene compounds and phenol compounds. For example, it is preferable to use a phenol sulfonic acid compound which is a phenol compound (such as phenol sulfonic acid or a substitute thereof). As already described, the phenolic hydroxy group also includes a salt (-OMe) of the phenolic hydroxy group.

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

The content of the organic shrinkage barrier in the negative electrode electrode material is preferably 0.005% by mass or more, for example. On the other hand, from the viewpoint of suppressing the deterioration of charge acceptability, the content of the organic shrinkage barrier in the negative electrode electrode material is preferably 0.3% by mass or less.

(Carbonaceous material)
As the carbonaceous material contained in the negative electrode electrode material, carbon black, graphite, hard carbon, soft carbon and the like can be used. Examples of carbon black include acetylene black, furnace black, and lamp black. Furness Black also includes Ketjen Black (trade name). The graphite may be any carbonaceous material containing a graphite-type crystal structure, and may be either artificial graphite or natural graphite. The negative electrode material may contain one kind of carbonaceous material, or may contain two or more kinds of carbonaceous material.

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

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

≪Analysis≫
The method for analyzing the polymer compound and the additive contained in the negative electrode material will be described below. Prior to measurement or analysis, a fully charged lead-acid battery is disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water to remove sulfuric acid from the negative electrode plate. Wash with water by pressing the pH test paper against the surface of the negative electrode plate washed with water until it is confirmed that the color of the test paper does not change. However, the time for washing with water shall be within 2 hours. The negative electrode plate washed with water is dried at 60 ± 5 ° C. for about 6 hours in a reduced pressure environment. If the negative electrode plate contains a sticking member, the sticking member is removed as necessary. Next, a sample (hereinafter referred to as sample A) is obtained by separating the negative electrode material from the negative electrode plate. Sample A is pulverized as needed and subjected to analysis.

(1) Analysis of polymer compound (1-1) Qualitative analysis of polymer compound (a) Analysis of oxyC _2-4 alkylene unit Crushed 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 polymer compound. Then, the solid content is removed by filtration. Chloroform solution in which the polymer compound obtained by extraction is dissolved or the polymer compound obtained by drying the chloroform solution is, for example, infrared spectroscopic spectrum, ultraviolet visible absorption spectrum, NMR spectrum, LC-MS and thermal decomposition GC-MS. The polymer compound is identified by obtaining information from at least one selected from.

Chloroform-soluble components are recovered from the chloroform solution in which the polymer compound obtained by extraction is dissolved by distilling off chloroform under reduced pressure. The chloroform-soluble component is dissolved in deuterated chloroform, and the ¹ H-NMR spectrum is measured under the following conditions. From this ¹ H-NMR spectrum, a peak with a chemical shift in the range of 3.2 ppm or more and 3.8 ppm or less is confirmed. Further, the type of _{oxyC 2-4} alkylene unit is specified from the peak in this range.

Device: AL400 type nuclear magnetic resonance device manufactured by JEOL Ltd. Observation frequency: 395.88 MHz
Pulse width: 6.30 μs
Pulse repetition time: 74.1411 seconds Total number of times: 32
Measurement temperature: Room temperature (20-35 ° C)
Criteria: 7.24 ppm
Sample tube diameter: 5 mm

¹ From the 1 H-NMR spectrum, the integral value (V1) of the peaks in which the chemical shift exists in the range of 3.2 ppm or more and 3.8 ppm or less is obtained. Further, for each of the hydrogen atoms of -CH ₂ -group and -CH <group bonded to the oxygen atom bonded to the terminal group of the polymer compound, the total of the integrated values (V2) of the peaks in the ¹ H-NMR spectrum is calculated. Ask. Then, from V1 and V2, the ratio of V1 to the total of V1 and V2 (= V1 / (V1 + V2) × 100 (%)) is obtained.

In the qualitative analysis, when the integral value of the peak in the ¹ H-NMR spectrum is obtained, two points in the ¹ H-NMR spectrum having no significant signal so as to sandwich the corresponding peak are determined, and these two points are determined. Each integrated value is calculated using the straight line connecting the intervals as the baseline. For example, for a peak in which the chemical shift is in the range of 3.2 ppm to 3.8 ppm, the straight line connecting the two points of 3.2 ppm and 3.8 ppm in the spectrum is used as the baseline. For example, for a peak in which the chemical shift exceeds 3.8 ppm and exists in the range of 4.0 ppm or less, the straight line connecting the two points of 3.8 ppm and 4.0 ppm in the spectrum is used as the baseline.

(B) Analysis of hydrophobic group in esterified product When the polymer compound is an esterified product of a hydroxy compound, the polymer compound obtained by drying a chloroform solution in which the polymer compound obtained by extraction is dissolved in the above (a). Is collected in a predetermined amount, and an aqueous potassium hydroxide solution is added. As a result, the esterified product is saponified to form a potassium fatty acid salt and a hydroxy compound. The above water-soluble potassium aqueous solution is added until saponification is completed. A solution of methanol and boron trifluoride is added to the resulting mixture and mixed to convert the potassium fatty acid salt into a fatty acid methyl ester. The obtained mixture is analyzed by thermal decomposition GC-MS under the following conditions to identify the hydrophobic group contained in the esterified product.
Analyzer: High-performance general-purpose gas chromatogram GC-2014 manufactured by Shimadzu Corporation
Column: DEGS (diethylene glycol succinate) 2.1m
Oven temperature: 180-120 ° C
Injection port temperature: 240 ° C
Detector temperature: 240 ° C
Carrier gas: He (flow rate: 50 mL / min)
Injection volume: 1 μL to 2 μL

(C) Analysis of hydrophobic group in etherified product When the polymer compound is an etherified product of a hydroxy compound, the polymer compound obtained by drying a chloroform solution in which the polymer compound obtained by extraction is dissolved in the above (a). , And add hydrogen iodide. As a result, an iodide (R ³ I) corresponding to the organic group (R ³ above) of the ether portion of the polymer compound is produced, and a diiodo C _2-4 alkane corresponding to the oxy C _2-4 alkylene unit is produced. do. The above hydrogen iodide is added in an amount sufficient to complete the conversion of the etherified iodide to the diiodo C _2-4 alkane. By analyzing the obtained mixture by thermal decomposition GC-MS under the same conditions as in (b) above, the hydrophobic group contained in the etherified product is identified.

(1-2) Quantitative analysis of polymer compound The appropriate amount of the above chloroform-soluble component was dissolved in deuterated chloroform together with mr (g) tetrachloroethane (TCE) measured with ^an accuracy of ± 0.0001 g, and 1H- Measure the NMR spectrum. The integral value (Sa) of the peak in which the chemical shift is in the range of 3.2 to 3.8 ppm and the integral value (Sr) of the peak derived from TCE are obtained, and the mass of the polymer compound in the negative electrode electrode material is obtained from the following formula. The standard content Cn (ppm) is determined.

Cn = Sa / Sr × Nr / Na × Ma / Mr × mr / m × 1000000
(In the formula, Ma is the molecular weight of the structure in which the chemical shift peaks in the range of 3.2 to 3.8 ppm (more specifically, the molecular weight of the oxyC _2-4 alkylene unit), and Na is the molecular weight of the repeating structure. It is the number of hydrogen atoms bonded to the carbon atom of the main chain. Nr and Mr are the number of hydrogen contained in the molecule of the reference substance and the molecular weight of the reference substance, respectively, and m (g) is the negative electrode material used for extraction. It is a mass.)
Since the reference substance in this analysis is TCE, Nr = 2 and Mr = 168. Moreover, m = 100.

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

In the quantitative analysis, the integrated value of the peak in the ¹ H-NMR spectrum is obtained by using the data processing software "ALICE" manufactured by JEOL Ltd.

(1-3) Mn measurement of polymer compound Using the above chloroform-soluble component, GPC measurement of the polymer compound is performed using the following equipment under the following conditions. Separately, a calibration curve (calibration curve) is created from the plot of Mn of the standard material and the elution time. Based on this calibration curve and the GPC measurement result of the polymer compound, Mn of the polymer compound is calculated. However, the esterified product or the etherified product may be in a decomposed state in the chloroform-soluble component.

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

(2) Analysis of organic shrinkage proofing agent (2-1) Qualitative analysis of organic shrinkage proofing agent in negative electrode material The crushed sample A is immersed in a 1 mol / L sodium hydroxide aqueous solution to extract the organic shrinkage proofing agent. The insoluble components are then filtered off the extract, the resulting solution is desalted, then concentrated and dried. Desalination is performed using a desalting column, by passing the solution through an ion exchange membrane, or by placing the solution in a dialysis tube and immersing it in distilled water. By drying this, a powder sample of an organic shrinkage proofing agent (hereinafter referred to as sample B) can be obtained.

The infrared spectroscopic spectrum measured using the sample B of the organic shrinkage proofing agent thus obtained, the ultraviolet visible absorption spectrum measured by diluting the sample B with distilled water or the like, and the sample B being used as heavy water or the like. Combining the NMR spectrum of the solution obtained by dissolving in a predetermined solvent or the information obtained from thermal decomposition GC-MS or the like capable of obtaining information on the individual compounds constituting the substance, the organic shrinkage proofing agent Identify the type.

(2-2) Quantification of the content of the organic shrinkage proofing agent in the negative electrode electrode material In the same manner as in (2-1) above, a solution is obtained after removing insoluble components from the extract by filtration. The ultraviolet-visible absorption spectrum is measured for each of the obtained solutions. The content of the organic shrinkage proofing agent in the negative electrode electrode material is determined by using the peak intensity characteristic of each organic shrinkage proofing agent and the calibration curve prepared in advance.

When a lead-acid battery having an unknown content of the organic shrinkage proof is obtained and the content of the organic shrinkage proofing agent is measured, the structural formula of the organic shrinkage proofing agent cannot be specified exactly, so that the same organic shrinkage proofing is applied to the calibration curve. The agent may not be available. In this case, calibration is performed using an organic shrink-proofing agent extracted from the negative electrode of the battery and a separately available organic polymer having a similar shape in the ultraviolet-visible absorption spectrum, infrared spectroscopic spectrum, NMR spectrum, and the like. By creating a line, the content of the organic shrink-proofing agent shall be measured using the ultraviolet-visible absorption spectrum.

(3) Quantification of carbonaceous material and barium sulfate To 10 g of crushed sample A, 50 ml of nitric acid having a concentration of 20% by mass is added and heated for about 20 minutes to dissolve the lead component as lead ions. The obtained solution is filtered to filter out solids such as carbonaceous materials and barium sulfate.

After the obtained solid content is dispersed in water to form a dispersion liquid, a carbonaceous material and components other than barium sulfate (for example, a reinforcing material) are removed from the dispersion liquid using a sieve. Next, the dispersion liquid is suction-filtered using a membrane filter whose mass has been measured in advance, and the membrane filter is dried together with the filtered sample in a dryer at 110 ° C. ± 5 ° C. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. The mass (Mm) of the sample C is measured by subtracting the mass of the membrane filter from the total mass of the dried mixed sample (hereinafter referred to as sample C) and the membrane filter. Then, the sample C is put into a crucible together with a membrane filter and incinerated at 1300 ° C. or higher. The remaining residue is barium oxide. The mass of barium oxide is converted into the mass of barium sulfate to obtain the mass (MB) of barium sulfate. The mass of the carbonaceous material is calculated by subtracting the mass MB from the mass Mm.

[Positive plate]
The positive electrode plate includes a positive electrode material and a positive current collector. The positive electrode plate can be formed by applying or filling a positive electrode paste to a positive electrode current collector, aging and drying to produce an unchemical positive electrode plate, and then forming an unchemical positive electrode plate. The positive electrode paste is prepared, for example, by kneading lead powder, an additive if necessary, and water and sulfuric acid (or an aqueous solution of sulfuric acid). The unchemical negative electrode plate may be aged at a temperature higher than room temperature and a high humidity.

The chemical conversion can be carried out by charging the electrode plate group in a state where the electrode plate group including the unchemical positive electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group.

(Positive current collector)
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 processing and punching processing. It is preferable to use a grid-shaped current collector as the positive electrode current collector because it is easy to support the positive electrode material.

As the lead alloy used for the positive electrode current collector, Pb—Sb based alloys, Pb—Ca based alloys, and Pb—Ca—Sn based alloys are preferable. The positive electrode current collector may include a surface layer. The composition of the surface layer and the inner layer of the positive electrode current collector may be different. The surface layer may be formed on a part of the positive electrode current collector. The surface layer may be formed only on the lattice portion of the positive electrode current collector, only the ear portion, or only the frame bone portion.

(Positive electrode material)
The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that develops a capacity by a redox reaction. The positive electrode material may contain additives, if necessary.

(AGM separator)
An AGM separator is arranged between the negative electrode plate and the positive electrode plate. The AGM separator is, for example, a non-woven fabric obtained by molding glass fibers into a sheet. Nonwoven fabric is a mat that is entwined without weaving fibers. The entire AGM separator may be made of glass fiber, or the AGM separator may contain glass fiber as a main component. The AGM separator may contain components other than glass fiber, for example, organic fiber, acid-resistant inorganic powder, polymer as a binder, and the like. When the main component of the AGM separator is glass fiber, the content of the glass fiber may be, for example, 60% by mass or more, or 70% by mass or more.

The average fiber diameter of the glass fiber may be, for example, 0.1 μm or more and 30 μm or less, or 0.5 μm or more and 15 μm or less. The average fiber diameter of the glass fiber may be obtained as the average value of 100 numerical values by obtaining the maximum diameter of an arbitrary cross section perpendicular to the length direction of any 100 fibers.

(Organic fiber)
The AGM separator may contain organic fibers. Polymer compounds are more likely to adsorb to organic fibers than hydrophilic glass fibers containing hydroxyl groups (-OH). Therefore, the polymer compound eluted from the negative electrode material into the electrolytic solution tends to be preferentially adsorbed to the organic fiber and stay in the AGM separator. As a result, it becomes more difficult for the polymer compound eluted in the electrolytic solution to reach the positive electrode plate. The AGM separator may contain organic fibers in an amount of, for example, 5% by mass or more and 20% by mass or less.

The content of the organic fiber contained in the AGM separator can be measured from the mass difference before and after the AGM separator is heated strongly in a muffle furnace. By igniting the AGM separator in a muffle furnace, the organic fibers are burned down. Therefore, the decrease in mass can be regarded as the mass of the organic fiber.

The organic fiber may be, for example, a resin fiber, a pulp fiber, or the like. Resins constituting the resin fibers include acrylic resins containing polyacrylonitrile units, acrylic acid units, methacrylic acid units, acrylic acid ester units, methacrylic acid ester units, polyester resins such as polyethylene terephthalate, and polyolefin resins such as polyethylene and polypropylene. Etc., but are not particularly limited.

The average fiber diameter of the organic fiber may be, for example, 1 μm or more and 15 μm or less, or 5 μm or more and 10 μm or less. The average fiber diameter of the organic fiber may be obtained as the average value of 100 numerical values by obtaining the maximum diameter of an arbitrary cross section perpendicular to the length direction of any 100 fibers.

(Ceramic powder)
The AGM separator may further contain a ceramic powder such as silica powder.

[Electrolytic solution]
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The above polymer compound may be contained in the electrolytic solution.

The electrolyte may optionally contain cations (eg, metal cations) and / or anions (eg, anions other than sulfate anions (such as phosphate ions)). Examples of the metal cation include at least one selected from the group consisting of Na ion, Li ion, Mg ion, and Al ion.

The specific gravity of the electrolytic solution in the fully charged lead storage battery at 20 ° C. is, for example, 1.20 or more, and may be 1.25 or more. The specific gravity of the electrolytic solution at 20 ° C. is 1.35 or less, preferably 1.32 or less.

The specific gravity of the electrolytic solution 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. ..

FIG. 1 is a cross-sectional view schematically showing the structure of an example of a control valve type lead acid battery. In FIG. 1, the lead-acid battery 1 includes a battery case 10 for accommodating a plate group 11 and an electrolytic solution (not shown). The upper opening of the battery case 10 is sealed by the lid 12A. The electrode plate group 11 is configured by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via a separator 4, respectively.

At the upper part of each of the plurality of negative electrode plates 2, an ear portion (not shown) for collecting electricity is provided so as to project upward. An ear portion (not shown) for collecting electricity is also provided on the upper portion of each of the plurality of positive electrode plates 3 so as to project upward. The ears of the negative electrode plate 2 are connected and integrated by a negative electrode strap (not shown). Similarly, the selvage portions of the positive electrode plates 3 are also connected and integrated by a positive electrode strap (not shown). The negative electrode strap is connected to a negative electrode column (not shown) which is an external terminal, and the positive electrode strap is connected to a positive electrode column (not shown) which is an external terminal.

The electric tank 10 is divided into a plurality of (three in the illustrated example) cell chambers 10R independently of each other, and one electrode plate group 11 is housed in each cell chamber 10R. The lid 12 includes an independent exhaust valve 13 for each cell chamber 10R. When the internal pressure of the cell chamber 10R exceeds a predetermined upper limit value, the exhaust valve 13 opens and the gas is directly discharged from the cell chamber 10R to the outside. When the internal pressure of the cell chamber 10R is equal to or less than the upper limit, oxygen generated in the positive electrode plate 3 is reduced by the negative electrode plate 2 in the same cell chamber 10R to generate water.

The structure of the control valve type lead-acid battery is not limited to the above. For example, FIG. 1 shows the case of each cell exhaust type, but the lid has a collective exhaust chamber that communicates with each cell chamber, and the number of collective exhaust chambers is smaller than the number of cell chambers (for example, one). It may be a collective exhaust type provided with.

In the present specification, the liquid reduction amount and the capacity retention rate at high rate discharge are evaluated by the float life test according to the following procedures, respectively. The test battery used for the evaluation has a rated voltage of 2 V / cell and a rated 10-hour rate capacity of 50 Ah.

≪Float life test≫
Float charging is continued at a constant voltage of 2.23 V / cell in a water tank at 60 ° C ± 3 ° C, and every January (30 days), capacity measurement and battery mass measurement at high rate discharge are performed under the following conditions. To carry out.

(A) Liquid reduction amount The liquid reduction amount is calculated as follows from the reduction amount of the battery mass.
Liquid reduction amount (%) = 100 × (Wa-Wb) / Wa
Wa: Battery mass before the test Wb: Battery mass after the test for a predetermined period

(B) Capacity retention rate at high-rate discharge 150A (3C (1C means the current (A) of the numerical value (Ah) described as the rated capacity)) for high-rate discharge up to a discharge termination voltage of 1.0V / cell. Implement and determine the initial capacity. After that, 90% of the discharge capacity is charged at 10 A (0.2 C), and then 45% of the discharge capacity (135% in total) is charged at 2.5 A (0.05 C). After that, float charging is continued at a constant voltage of 2.23 V / cell. Then, every 30 days, the capacity is measured at the same high rate discharge, and the ratio of the obtained capacity to the initial capacity is obtained as a percentage.

The control valve type lead acid battery according to the present invention is collectively described below.

(1) A control valve type lead-acid battery.
A plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution are provided.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and an AGM separator interposed between the positive electrode plate and the negative electrode plate.
The pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa or less.
The density of the AGM separator when a compressive force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less.
The negative electrode plate contains a negative electrode material and contains a negative electrode material.
The negative electrode material contains a polymer compound and contains.
The polymer compound is a control valve type lead-acid battery having a peak in the range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent.

(2) The control valve type lead-acid battery according to (1) above, wherein the polymer compound has a repeating structure of an _{oxyC 2-4} alkylene unit.

(3) A control valve type lead-acid battery.
A plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution are provided.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and an AGM separator interposed between the positive electrode plate and the negative electrode plate.
The pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa or less.
The density of the AGM separator when a compressive force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less.
The negative electrode plate contains a negative electrode material and contains a negative electrode material.
The negative electrode material contains a polymer compound and contains.
The polymer compound is a control valve type lead acid battery having a repeating structure of an _{oxyC 2-4} alkylene unit.

(4) The above (2) or (3), wherein the polymer compound contains at least one selected from the group consisting of the hydroxy compound having the repeating structure, the etherified product of the hydroxy compound, and the esterified product of the hydroxy compound. The control valve type lead acid battery described.

(5) The hydroxy compound is selected from the group consisting of a poly C _2-4 alkylene glycol, a copolymer containing a repeating structure of an oxy C _2-4 alkylene unit, and a poly C _2-4 alkylene oxide adduct of a polyol. The control valve type lead-acid battery according to (4) above, which is at least one kind of lead-acid battery.

(6) The control valve type lead-acid battery according to any one of (2) to (5) above, wherein the oxyC _2-4 alkylene unit is an oxypropylene unit.

(7) The control valve type lead-acid battery according to any one of (2) to (5) above, wherein the oxyC _2-4 alkylene unit is an oxyethylene unit.

(8) The polymer compound contains an oxygen atom bonded to the terminal group and -CH ₂ -group and / or -CH <group bonded to the oxygen atom.
In the ¹ H-NMR spectrum, the integral value of the peak, the integral value of the peak of the _−CH2 − group hydrogen atom, and the integral value of the peak of the −CH <group hydrogen atom of the integral value of the peak. The control valve type lead storage battery according to any one of (1) to (8) above, wherein the ratio of the above to the total is 85% or more.

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

(10) The control valve type lead-acid battery according to any one of (1) to (9) above, wherein the content of the polymer compound in the negative electrode material is in the range of 30 ppm to 500 ppm on a mass basis.

(11) The control valve type lead-acid battery according to any one of (1) to (10) above, wherein the polymer compound contains a compound having a number average molecular weight of 10,000 or less.

(12) The control valve type lead-acid battery according to any one of (1) to (11) above, wherein the polymer compound contains a compound having a number average molecular weight of 500 or more.

(13) The control valve type lead-acid battery according to any one of (1) to (12) above, wherein the AGM separator contains organic fibers in an amount of 5% by mass or more and 20% by mass or less.

[Example]
Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<< Lead-acid batteries E1 to E6, R1 >>
(1) Preparation of lead-acid battery (a) Preparation of negative electrode plate A suitable amount of lead powder as a raw material, lignin as an organic shrinkage proofing agent, barium sulfate, carbon black, and polyethylene glycol (PEG) as a polymer compound. Mix with aqueous sulfuric acid to give a negative paste. The content of the polymer compound in the negative electrode electrode material obtained by the above procedure is as shown in Tables 1 and 2, the content of the organic shrinkage proofing agent is 0.1% by mass, and the content of barium sulfate is 0. Each component is mixed so that the content of 4% by mass and the content of carbon black is 0.2% by mass. The concentration and amount of the sulfuric acid aqueous solution are adjusted so that the density of the negative electrode material contained in the fully charged lead-acid battery after chemical conversion is 3.6 g / cm ³ . The negative electrode paste is filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy and aged and dried to obtain an unchemicald negative electrode plate.

The number average molecular weight Mn of the polymer compound (polyethylene glycol (PEG)) measured by the above-mentioned procedure is 500, and in the ¹ H-NMR spectrum of the polymer compound, a chemical of 3.2 ppm or more and 3.8 ppm or less. A peak derived from -CH _2- of the oxyethylene unit is observed in the shift range. Further, in the ¹ H-NMR spectrum, the integrated value of the peak derived from -CH _2- of the oxyethylene unit, the integrated value of this peak, and the -CH ₂ -group bonded to the oxygen atom bonded to the terminal group and / /. Alternatively, the ratio of the peak of the hydrogen atom of the -CH <group to the integrated value is 99%.

(B) Preparation of positive electrode plate The lead powder as a raw material is mixed with an aqueous sulfuric acid solution to obtain a positive electrode paste. The positive electrode paste is filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy and aged and dried to obtain an unchemicald positive electrode plate.

(C) Preparation of AGM Separator The 20 kPa density obtained by the above-mentioned method is 0.14 g / cm ³ , and the thickness t (cm) per AGM separator obtained by the above-mentioned method is 0.25 cm (that is,). Prepare an AGM separator (2.5 mm). 90% by mass of the AGM separator is glass fiber (average fiber diameter 0.8 μm), and 10% by mass is organic fiber.

(D) Preparation of test battery The test battery has a rated voltage of 2V and a rated 10-hour rate capacity of 50Ah. The electrode plate group of the test battery is composed of 5 positive electrode plates and 6 negative electrode plates. The positive electrode plate and the negative electrode plate are alternately laminated with the AGM separator interposed therebetween to form a group of electrode plates. A group of electrode plates is housed in a polypropylene electric tank together with an electrolytic solution (sulfuric acid aqueous solution) and chemically formed in the electric tank to produce a control valve type lead-acid battery. The tension required by the method described above is 10 kPa. The specific gravity of the electrolytic solution in a fully charged lead-acid battery at 20 ° C. is 1.28.

(2) Float life test A float life test is carried out by the method described above, and the amount of liquid reduction and the capacity retention rate at high rate discharge are determined every month. The results of the liquid reduction amount are shown in Table 1. Table 2 shows the capacity retention rate (HR capacity retention rate) in high-rate discharge.

From Table 1, it can be seen that when polyethylene glycol (PEG) is contained as the polymer compound in the negative electrode material, the larger the PEG content in the negative electrode material, the greater the effect of suppressing the liquid reduction. Further, it can be seen that when the PEG content is 30 ppm or more, the liquid reduction is suppressed more remarkably.

From Table 2, when polyethylene glycol (PEG) is contained as a polymer compound in the negative electrode material, the tension of the electrode plates is 10 kPa or more and 40 kPa or less, and the 20 kPa density of the AGM separator is 0.14 g / cm. It can be understood that the decrease in the capacity retention rate in the high rate discharge is suppressed by setting the value to ³ or more and 0.20 g / cm ³ or less. Further, it can be seen that when the PEG content is 30 ppm or more and 600 ppm or less, the capacity retention rate in high-rate discharge is more remarkably improved.

<< Lead-acid batteries E7 to E9, R2 >>
A control valve type lead-acid battery is produced in the same manner as in Example E3 (PEG content 80 ppm) except that the tension required by the method described above is set to the values shown in Tables 3 and 4, and a float life test is carried out. The results of the liquid reduction amount are shown in Table 3. Table 4 shows the capacity retention rate in high-rate discharge.

From Table 3, it can be seen that even when polyethylene glycol (PEG) is contained as a polymer compound in the negative electrode electrode material, the effect of suppressing liquid reduction is small when the tension of the electrode plate group is less than 10 kPa. On the other hand, when the tension of the electrode plate group is 10 kPa or more, the effect of suppressing the liquid reduction is remarkable.

From Tables 4 and 2, regardless of whether polyethylene glycol (PEG) is contained as a polymer compound in the negative electrode material, when the tension of the electrode plate group is less than 10 kPa, the capacity retention rate in high-rate discharge is improved. It can be seen that there is almost no effect. On the other hand, when the tension of the electrode plate group is 10 kPa or more, the larger the tension, the higher the capacity retention rate in high-rate discharge.

<< Lead-acid batteries R3 to R7 >>
A control valve type lead-acid battery is produced in the same manner as in Comparative Example R1 (PEG content 0 ppm) except that the tension required by the method described above is set to the values shown in Tables 3 and 4, and a float life test is carried out. The results of the liquid reduction amount are shown in Table 5. Table 6 shows the capacity retention rate in high-rate discharge.

From Table 5, it can be seen that when the negative electrode material does not contain the polymer compound, the liquid reduction cannot be suppressed regardless of the tension of the electrode plate group.

From Table 6, it can be seen that when the negative electrode material does not contain the polymer compound, the capacity retention rate in high-rate discharge can hardly be improved regardless of the tension of the electrode plate group.

<< Lead-acid batteries E10-12, R8-9 >>
A control valve type lead-acid battery was produced in the same manner as in Example E3 (PEG content 80 ppm) except that the 20 kPa density of the AGM separator obtained by the above-mentioned method was set to the values shown in Tables 7 and 8, and a float life test was conducted. implement. The results of the liquid reduction amount are shown in Table 7. Table 8 shows the capacity retention rate in high-rate discharge.

From Table 7, it can be seen that when the 20 kPa density of the AGM separator exceeds 0.2 g / cm ³ , the effect of suppressing the liquid reduction becomes small. Therefore, the 20 kPa density of the AGM separator needs to be 0.2 g / cm ³ or less.

From Table 8, it can be seen that when the 20 kPa density of the AGM separator is less than 0.14 g / cm ³ , the capacity retention rate in high-rate discharge cannot be improved. Further, it can be seen that even if the 20 kPa density of the AGM separator exceeds 0.2 g / cm ³ , the capacity retention rate in high-rate discharge cannot be improved. Therefore, the 20 kPa density of the AGM separator needs to be 0.14 g / cm ³ or more and 0.2 g / cm ³ or less.

<< Lead-acid battery E13-17 >>
A control valve type lead-acid battery was produced in the same manner as in Example E3 (PEG content 80 ppm) except that the organic fiber content obtained by the above-mentioned method was set to the values shown in Tables 9 and 10, and a float life test was conducted. implement. The results of the liquid reduction amount are shown in Table 9. Table 10 shows the capacity retention rate in high-rate discharge.

From Table 9, it can be seen that when the AGM separator contains organic fibers, it is desirable that the content thereof is 20% by mass or less.

From Table 9, when the AGM separator contains organic fibers, it is desirable that the content is 5% by mass or more, and up to 20% by mass, the larger the content of organic fibers, the higher the capacity retention rate in high-rate discharge. It can be seen that it is advantageous for the improvement of.

<< Lead-acid battery E18-23, R10 >>
A control valve type lead-acid battery is prepared and a float life test is carried out in the same manner as in Tables 1 and 2, except that the polymer compound is changed from PEG to polyethylene glycol oleate which is an esterified product of PEG. The results of the liquid reduction amount are shown in Table 11. Table 12 shows the capacity retention rate in high-rate discharge.

<< Lead-acid batteries E24-29, R11 >>
A control valve type lead-acid battery is prepared and a float life test is carried out in the same manner as in Tables 1 and 2, except that the polymer compound is changed from PEG to polyethylene glycol dilaurate which is an esterified product of PEG. The results of the liquid reduction amount are shown in Table 13. Table 14 shows the capacity retention rate in high-rate discharge.

<< Lead-acid batteries E30-35, R12 >>
A control valve type lead-acid battery is prepared and a float life test is carried out in the same manner as in Tables 1 and 2, except that the polymer compound is changed from PEG to polyethylene glycol distearate which is an esterified product of PEG. The results of the liquid reduction amount are shown in Table 15. Table 16 shows the capacity retention rate in high-rate discharge.

<< Lead-acid batteries E36-41, R13 >>
A control valve type lead-acid battery is prepared and a float life test is carried out in the same manner as in Tables 1 and 2, except that the polymer compound is changed from PEG to polyethylene glycol dioleate which is an esterified product of PEG. The results of the liquid reduction amount are shown in Table 17. Table 18 shows the capacity retention rate in high-rate discharge.

The results shown in Tables 11 to 18 show that, as in the case of using polyethylene glycol (PEG) as the polymer compound, when the esterified product of PEG is used, the tension of the electrode plates is 10 kPa or more and 40 kPa or less, and It can be understood that by setting the 20 kPa density of the AGM separator to 0.14 g / cm ³ or more and 0.20 g / cm ³ or less, the decrease in the capacity retention rate at high rate discharge is suppressed while suppressing the liquid reduction. ..

The control valve type lead acid battery according to the present invention is suitable as a stationary control valve type lead acid battery such as an uninterruptible power supply (UPS), but its use is not particularly limited.

1: Control valve type lead acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 11: Electrode plate group 10: Electric tank 10R: Cell chamber 12: Cover 13: Exhaust valve

Claims (13)

A plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution are provided.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and an AGM separator interposed between the positive electrode plate and the negative electrode plate.
The pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa or less.
The density of the AGM separator when a compressive force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less.
The negative electrode plate contains a negative electrode material and contains a negative electrode material.
The negative electrode material contains a polymer compound and contains.
The polymer compound is a control valve type lead-acid battery having a peak in the range of 3.2 ppm or more and 3.8 ppm or less in a chemical shift of ¹ H-NMR spectrum measured using deuterated chloroform as a solvent. The control valve type lead-acid battery according to claim 1, wherein the polymer compound has a repeating structure of an _{oxyC 2-4} alkylene unit. A plate group, an electrolytic solution, and an electric tank for accommodating the electrode plate group and the electrolytic solution are provided.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and an AGM separator interposed between the positive electrode plate and the negative electrode plate.
The pressure applied to the electrode plate group in the electric tank in the stacking direction of the positive electrode plate and the negative electrode plate is 10 kPa or more and 40 kPa or less.
The density of the AGM separator when a compressive force of 20 kPa is applied in the thickness direction is 0.14 g / cm ³ or more and 0.20 g / cm ³ or less.
The negative electrode plate contains a negative electrode material and contains a negative electrode material.
The negative electrode material contains a polymer compound and contains.
The polymer compound is a control valve type lead acid battery having a repeating structure of an _{oxyC 2-4} alkylene unit. The control valve type lead according to claim 2 or 3, wherein the polymer compound comprises at least one selected from the group consisting of the hydroxy compound having the repeating structure, the etherified product of the hydroxy compound, and the esterified product of the hydroxy compound. Storage battery. The hydroxy compound is at least one selected from the group consisting of a poly C _2-4 alkylene glycol, a copolymer containing a repeating structure of an oxy C _2-4 alkylene unit, and a poly C _2-4 alkylene oxide adduct of a polyol. The control valve type lead-acid battery according to claim 4. The control valve type lead-acid battery according to any one of claims 2 to 5, wherein the oxyC _2-4 alkylene unit is an oxypropylene unit. The control valve type lead-acid battery according to any one of claims 2 to 5, wherein the oxyC _2-4 alkylene unit is an oxyethylene unit. The polymer compound comprises an oxygen atom attached to the terminal group and an -CH ₂ -group and / or -CH <group attached to the oxygen atom.
In the ¹ H-NMR spectrum, the integral value of the peak, the integral value of the peak of the _−CH2 − group hydrogen atom, and the integral value of the peak of the −CH <group hydrogen atom of the integral value of the peak. The control valve type lead storage battery according to any one of claims 1 to 7, wherein the ratio of the above to the total is 85% or more. The polymer compound has one or more hydrophobic groups and
The control valve type lead-acid battery according to any one of claims 1 to 8, wherein at least one of the hydrophobic groups is a long-chain aliphatic hydrocarbon group having 8 or more carbon atoms. The control valve type lead-acid battery according to any one of claims 1 to 9, wherein the content of the polymer compound in the negative electrode material is in the range of 30 ppm to 500 ppm on a mass basis. The control valve type lead-acid battery according to any one of claims 1 to 10, wherein the polymer compound contains a compound having a number average molecular weight of 10,000 or less. The control valve type lead-acid battery according to any one of claims 1 to 11, wherein the polymer compound contains a compound having a number average molecular weight of 400 or more. The control valve type lead-acid battery according to any one of claims 1 to 12, wherein the AGM separator contains organic fibers in an amount of 5% by mass or more and 20% by mass or less.

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