JP2020057541A - Lead acid battery - Google Patents

Abstract

To suppress the detachment of additives in a negative electrode and to improve the life of a lead acid battery in a low temperature environment.SOLUTION: A lead acid battery according to an embodiment of the present invention includes a positive electrode, a negative electrode, and a separator, and the negative electrode includes a current collector and a negative electrode active material held by the current collector, and the negative electrode active material includes a resin having a first structural unit derived from bisphenol A, and a second structural unit derived from bisphenol S, and lignin sulfonic acid or a salt thereof.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lead storage battery.

  Various additives are added to a negative electrode of a lead-acid battery used for a battery of an automobile, a backup power supply, a main power supply of an electric vehicle, or the like, depending on required characteristics. For example, Patent Document 1 discloses that a bisphenol A / sulfonic acid / formaldehyde condensate, lignin, or the like is added to a negative electrode in order to further improve the discharge performance of the negative electrode.

JP 2012-43594 A

  By the way, the manufacturing process of a lead storage battery includes a process called a chemical conversion treatment. The chemical conversion treatment is performed, for example, by applying a current while the positive electrode, the negative electrode, and the separator are immersed in an electrolytic solution (dilute sulfuric acid). According to the study of the present inventors, it has been found that when a negative electrode as disclosed in Patent Document 1 is used, the additive may be detached from the negative electrode by the chemical conversion treatment. From the viewpoint of efficiently using the additive, it is desirable to suppress the elimination of such an additive as much as possible. On the other hand, it was also found that changing the composition of the additive so as not to be easily desorbed may adversely affect the life of the lead storage battery in a low-temperature environment.

  Therefore, an object of the present invention is to suppress the desorption of additives from a negative electrode and to improve the life of a lead storage battery in a low-temperature environment.

  One embodiment of the present invention includes a positive electrode, a negative electrode, and a separator, the negative electrode includes a current collector, and a negative electrode active material held by the current collector, and the negative electrode active material is derived from bisphenol A. A lead storage battery comprising: a resin having a first structural unit and a second structural unit derived from bisphenol S; and ligninsulfonic acid or a salt thereof.

  Each of the first structural unit and the second structural unit may have a group derived from aminobenzenesulfonic acid or a derivative thereof, and may have a group derived from formaldehyde or a derivative thereof.

  ADVANTAGE OF THE INVENTION According to this invention, while the desorption of the additive in a negative electrode can be suppressed, the life of the lead storage battery in a low temperature environment can be improved.

It is a perspective view showing the whole composition and internal structure of the lead storage battery concerning one embodiment. FIG. 2 is a perspective view showing an electrode group of the lead storage battery shown in FIG. 1.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

  FIG. 1 is a perspective view showing an overall configuration and an internal structure of a lead storage battery according to one embodiment. As shown in FIG. 1, a lead storage battery 1 is a liquid lead storage battery including a battery case 2 having an open upper surface and a lid 3 for closing the opening of the battery case 2. The battery case 2 and the lid 3 are formed of, for example, polypropylene. The lid 3 is provided with a negative electrode terminal 4, a positive electrode terminal 5, and a liquid port plug 6 for closing a liquid injection port provided on the lid 3.

  Inside the container 2, an electrode group 7, a negative pole 8 connecting the electrode group 7 to the negative terminal 4, a positive pole (not shown) connecting the electrode group 7 to the positive terminal 5, Is housed.

  The electrolyte contains diluted sulfuric acid. The diluted sulfuric acid may be, for example, diluted sulfuric acid having a specific gravity (20 ° C.) after chemical formation of 1.25 to 1.33. The electrolytic solution may further contain aluminum ions. Aluminum ions can be contained in the electrolytic solution by dissolving aluminum sulfate, sulfite, carbonate, bicarbonate, phosphate, borate, metalate, and the like in dilute sulfuric acid. The concentration of aluminum ions in the electrolyte may be, for example, not less than 0.005 mol / L and not more than 0.4 mol / L.

  FIG. 2 is a perspective view showing the electrode group 7. As shown in FIG. 2, the electrode group 7 includes a plate-shaped negative electrode 9, a plate-shaped positive electrode 10, and a separator 11 disposed between the negative electrode 9 and the positive electrode 10. The negative electrode 9 has a negative electrode current collector 12 and a negative electrode active material 13 held on the negative electrode current collector 12. The positive electrode 10 has a positive electrode current collector 14 and a positive electrode active material 15 held on the positive electrode current collector 14. In the present specification, the negative electrode after the formation of the negative electrode without the negative electrode current collector is defined as a “negative electrode active material”, and the negative electrode after the formation without the positive electrode current collector is defined as “positive electrode active material”.

  The electrode group 7 has a structure in which a plurality of negative electrodes 9 and positive electrodes 10 are alternately stacked in a direction substantially parallel to the opening surface of the battery case 2 via a separator 11. That is, the negative electrode 9 and the positive electrode 10 are arranged such that their main surfaces extend in a direction perpendicular to the opening surface of the battery case 2. In the electrode group 7, the negative electrode ears 12 a of each negative electrode current collector 12 in the plurality of negative electrodes 9 are collectively welded to each other by the negative electrode strap 16. Similarly, the positive electrode lugs 14 a of the respective positive electrode current collectors 14 in the plurality of positive electrodes 10 are collectively welded by the positive electrode strap 17. The negative electrode strap 16 and the positive electrode strap 17 are connected to the negative terminal 4 and the positive terminal 5 via the negative pole 8 and the positive pole, respectively.

The separator 11 is formed in a bag shape, for example, and accommodates the negative electrode 9. The separator 11 is formed of, for example, polyethylene (PE), polypropylene (PP), or the like. The separator 11 may be formed by attaching inorganic particles such as SiO ₂ and Al ₂ O ₃ to a woven fabric, a nonwoven fabric, a porous film, or the like made of these materials.

  The negative electrode current collector 12 and the positive electrode current collector 14 are each formed of a lead alloy. The lead alloy may be an alloy containing Sn, Ca, Sb, Se, Ag, Bi, etc. in addition to Pb, and specifically, for example, an alloy containing Pb, Sn and Ca (Pb-Sn -Ca-based alloy).

The positive electrode active material 15 contains at least PbO ₂ as a Pb component, and may further contain a Pb component other than PbO ₂ (for example, PbSO ₄ ) as necessary. The content of the Pb component may be 90% by mass or more or 95% by mass or more, and may be 99% by mass or less or 98% by mass or less based on the total mass of the positive electrode active material.

  The positive electrode active material 15 may further include a carbon material, a reinforcing short fiber, and the like. Examples of the carbon material include carbon black and graphite. Examples of the carbon black include furnace black, channel black, acetylene black, thermal black, and Ketjen black. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, and polyethylene terephthalate fibers.

The negative electrode active material 13 contains at least Pb (simple substance) as a Pb component, and may further contain a Pb component other than Pb (for example, PbSO ₄ ) as necessary. The negative electrode active material 13 preferably contains porous spongy lead as a Pb component. The content of the Pb component may be 90% by mass or more or 95% by mass or more, and may be 99% by mass or less or 98% by mass or less based on the total mass of the negative electrode active material.

  The negative electrode active material 13 includes a first structural unit derived from bisphenol A (2,2-bis (4-hydroxyphenyl) propane) and a second structural unit derived from bisphenol S (bis (4-hydroxyphenyl) sulfone). (Hereinafter also referred to as “bisphenol-based resin”).

  In the bisphenol-based resin, each of the first structural unit and the second structural unit has a group derived from aminobenzenesulfonic acid or a derivative thereof (hereinafter, these are collectively referred to as “aminobenzenesulfonic acid group”). You may.

  Examples of the aminobenzenesulfonic acid include 2-aminobenzenesulfonic acid (also known as orthonilic acid), 3-aminobenzenesulfonic acid (also known as metanilic acid), and 4-aminobenzenesulfonic acid (also known as sulfanilic acid).

Examples of the derivative of aminobenzenesulfonic acid include a compound in which some hydrogen atoms of aminobenzenesulfonic acid are substituted with an alkyl group (for example, an alkyl group having 1 to 5 carbon atoms), a sulfo group of aminobenzenesulfonic acid (-SO Compounds in which the hydrogen atom of ₃ H) is substituted with an alkali metal (for example, sodium and potassium). Examples of the compound in which some hydrogen atoms of aminobenzenesulfonic acid are substituted with an alkyl group include 4- (methylamino) benzenesulfonic acid, 3-methyl-4-aminobenzenesulfonic acid, and 3-amino-4-methylbenzene. Sulfonic acid, 4- (ethylamino) benzenesulfonic acid, 3- (ethylamino) -4-methylbenzenesulfonic acid and the like can be mentioned. Compounds in which the hydrogen atom of the sulfo group of aminobenzenesulfonic acid is substituted with an alkali metal include sodium 2-aminobenzenesulfonate, sodium 3-aminobenzenesulfonate, sodium 4-aminobenzenesulfonate, and 2-aminobenzenesulfone. And potassium 3-aminobenzenesulfonate, potassium 4-aminobenzenesulfonate, and the like.

  The bisphenol-based resin is obtained, for example, by reacting bisphenol A and bisphenol S. Preferably, in addition to bisphenol A and bisphenol S, aminobenzenesulfonic acid or a derivative thereof, and / or formaldehyde or a derivative thereof Is further reacted (for example, by a known method described in WO 2016/088836). That is, each of the first structural unit and the second structural unit in the bisphenol-based resin preferably further has a group derived from formaldehyde or a derivative thereof (hereinafter, also referred to as “formaldehyde group”). The derivative of formaldehyde may be, for example, paraformaldehyde, hexamethylenetetramine, trioxane and the like.

式中、Ｙ^１１及びＹ^１２は、それぞれ独立に、置換又は無置換のフェニレン基を表し、Ｒ^１１、Ｒ^１２、Ｒ^１３、Ｒ^１４、Ｒ^１５及びＲ^１６は、それぞれ独立に、アルカリ金属原子又は水素原子を表し、ｎ１１及びｎ１２は、それぞれ独立に、０又は１を表す。 The first structural unit is, for example, a structural unit represented by the following formula (1-1) or (1-2).

In the formula, Y ¹¹ and Y ¹² each independently represent a substituted or unsubstituted phenylene group, and R ¹¹ , R ¹² , R ¹³ , R ¹⁴ , R ¹⁵ and R ¹⁶ each independently represent an alkali metal atom. Or n represents a hydrogen atom, and n11 and n12 each independently represent 0 or 1.

式中、Ｙ^２１及びＹ^２２は、それぞれ独立に、置換又は無置換のフェニレン基を表し、Ｒ^２１、Ｒ^２２、Ｒ^２３、Ｒ^２４、Ｒ^２５及びＲ^２６は、それぞれ独立に、アルカリ金属原子又は水素原子を表し、ｎ２１及びｎ２２は、それぞれ独立に、０又は１を表す。 The second structural unit is, for example, a structural unit represented by the following formula (2-1) or (2-2).

In the formula, Y ²¹ and Y ²² each independently represent a substituted or unsubstituted phenylene group, and R ²¹ , R ²² , R ²³ , R ²⁴ , R ²⁵ and R ²⁶ each independently represent an alkali metal atom. Or n represents a hydrogen atom, and n21 and n22 each independently represent 0 or 1.

The substituted phenylene group represented by Y ¹¹ , Y ¹² , Y ²¹ or Y ²² is, for example, a hydrogen atom directly bonded to a carbon atom constituting a phenyl ring substituted with an alkyl group having 1 to 5 carbon atoms. Or a phenyl group. The alkali metal atom represented by R ^{11 to} R ¹⁶ or R ^{21 to} R ²⁶ may be, for example, a sodium atom or a potassium atom.

  The content of the first structural unit is 0.5 mol or more, 0.55 mol or more, and 0.6 mol or more with respect to a total of 1 mol of the content of the first structural unit and the content of the second structural unit. It may be at least mol, at least 0.65 mol, or at least 0.7 mol, and at most 0.9 mol, at most 0.85 mol, or at most 0.8 mol.

  The content of the second structural unit is 0.1 mol or more, 0.15 mol or more, or 0.1 mol or more based on 1 mol of the total of the content of the first structural unit and the content of the second structural unit. It may be at least 2 mol, and may be at most 0.5 mol, at most 0.45 mol, at most 0.4 mol, at most 0.35 mol, or at most 0.3 mol.

  The content of the aminobenzenesulfonic acid group is 0.6 mol or more, 0.65 mol or more, 0.7 mol or more, based on the total of 1 mol of the content of the first structural unit and the content of the second structural unit. It may be at least mol, or at least 0.75 mol, and may be at most 1 mol, at most 0.95 mol, at most 0.9 mol, or at most 0.85 mol. The content of the aminobenzenesulfonic acid group means the total content of all the aminobenzenesulfonic acid groups contained in the bisphenol-based resin, and the aminobenzenesulfonic acid group is contained in any structural unit. You may.

  The content of the formaldehyde group is 2 mol or more, 2.1 mol or more, or 2.2 mol or more based on 1 mol of the total of the content of the first structural unit and the content of the second structural unit. And may be up to 3.5 moles, up to 3.2 moles, or up to 3 moles. The content of the formaldehyde group means the sum of the content of all the formaldehyde groups contained in the bisphenol-based resin, and the formaldehyde group may be contained in any structural unit.

  The content of the first structural unit, the content of the second structural unit, the content of the aminobenzenesulfonic acid group, and the content of the formaldehyde group described above are determined, for example, by using bisphenol A when synthesizing a bisphenol-based resin. By adjusting the amounts of phenol, bisphenol S, aminobenzenesulfonic acid or a derivative thereof, and formaldehyde or a derivative thereof, the above ranges can be achieved.

  The bisphenol-based resin may include only the first structural unit and the second structural unit, and may further include a structural unit other than the first structural unit and the second structural unit. The other structural unit may be, for example, a structural unit derived from a phenol compound other than bisphenol A and bisphenol S (which may or may not have an aminobenzenesulfonic acid group).

  Phenol compounds other than bisphenol A and bisphenol S include, for example, bis (4-hydroxyphenyl) methane, 1,1-bis (4-hydroxyphenyl) ethane, 2,2-bis (4-hydroxyphenyl) hexafluoropropane 1,1-bis (4-hydroxyphenyl) -1-phenylethane, 2,2-bis (4-hydroxyphenyl) butane, bis (4-hydroxyphenyl) diphenylmethane, 1,1-bis (4-hydroxyphenyl) ) Cyclohexane, 1,1-bis (4-hydroxyphenyl) -3,3,5-trimethylcyclohexane and the like.

  The sum of the content of the first structural unit and the content of the second structural unit is, for example, 90 mol% or more, 95 mol% or more, or 98 mol% based on all the structural units contained in the bisphenol-based resin. That is all. When the bisphenol-based resin further contains other structural units, the content of the other structural units may be, for example, 1 mol% or more, and 10 mol% or less, based on all the structural units contained in the bisphenol-based resin. 5 mol% or less, or 2 mol% or less.

  The weight average molecular weight of the bisphenol-based resin may be 20,000 or more, 30,000 or more, 40,000 or more, or 50,000 or more, and may be 80,000 or less, 70,000 or less, or 60,000 or less.

The weight average molecular weight of the bisphenol-based resin can be measured, for example, by gel permeation chromatography (hereinafter, referred to as “GPC”) under the following conditions.
(GPC conditions)
Apparatus: High-performance liquid chromatograph LC-2200 Plus (manufactured by JASCO Corporation)
Pump: PU-2080
Differential refractometer: RI-2031
Detector: UV-visible absorption spectrophotometer UV-2075 (λ: 254 nm)
Column oven: CO-2065
Column: TSKgel SuperAW (4000), TSKgel SuperAW (3000), TSKgel SuperAW (2500) (manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Eluent: methanol solution containing LiBr (10 mM) and triethylamine (200 mM) Flow rate: 0.6 mL / min Molecular weight standard sample: polyethylene glycol (molecular weight: 1.10 × 10 ⁶ , 5.80 × 10 ⁵ , 2.55 × 10 ⁵ , 1.46 × 10 ⁵ , 1.01 × 10 ⁵ , 4.49 × 10 ⁴ , 2.70 × 10 ⁴ , 2.10 × 10 ⁴ ; manufactured by Tosoh Corporation; diethylene glycol (molecular weight: 1) 0.06 × 10 ² ; manufactured by Kishida Chemical Co., Ltd.), dibutylhydroxytoluene (molecular weight: 2.20 × 10 ² ; manufactured by Kishida Chemical Co., Ltd.)

  The content of the bisphenol-based resin may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more based on the total mass of the negative electrode active material, 2% by mass or less, 1% by mass % Or 0.5% by mass or less.

The negative electrode active material 13 further includes lignin sulfonic acid or a salt thereof (hereinafter, also referred to as “lignin sulfonic acid (salt)”). Lignin sulfonic acid (salt) is lignin sulfonic acid or a salt thereof in which a part of the lignin degradation product is sulfonated. Lignin sulfonic acid (salt) has a structural unit derived from lignin as a structural unit derived from a phenolic compound, and has a sulfonic acid group or a sulfonic acid group. Lignin sulfonic acid (salt) has, for example, a structure in which a sulfonic acid group or a sulfonate group is bonded to a carbon atom at the α-position adjacent to a phenylene group. Lignin sulfonic acid (salt) has, for example, a structure represented by the following formula (3).

In the formula (3), R ¹ represents a metal atom or a hydrogen atom. The metal atom is, for example, a sodium atom, a potassium atom, a magnesium atom or a calcium atom.

  Lignin sulfonic acid (salt) is obtained by, for example, neutralizing black liquor remaining after digesting wood chips to remove cellulose with sodium hydroxide, potassium hydroxide, calcium hydroxide, magnesium hydroxide, or the like. Can be.

  The weight average molecular weight of lignin sulfonic acid (salt) is preferably 3,000 or more, more preferably 7000 or more, still more preferably 8,000 or more, preferably 70,000 or less, more preferably 50,000 or less, further preferably 40,000 or less, and particularly preferably. Is 30,000 or less, very preferably 20,000 or less. The weight average molecular weight of ligninsulfonic acid (salt) can be measured by GPC under the same conditions as those described for the bisphenol-based resin described above.

  The content of lignin sulfonic acid (salt) may be 0.01% by mass or more, 0.05% by mass or more, or 0.1% by mass or more, based on the total mass of the negative electrode active material, and may be 2% by mass. Hereinafter, it may be 1% by mass or less, or 0.5% by mass or less.

  The negative electrode active material 13 may further include a carbon material. The carbon material may be, for example, carbon black, graphite, or the like. Examples of the carbon black include furnace black, channel black, acetylene black, thermal black, and Ketjen black. The content of the carbon material may be 0.1% by mass or more, based on the total mass of the negative electrode active material, and may be 3.5% by mass or less, 3.0% by mass or less, 2.5% by mass or less, or 2% by mass or less. 0.0% by mass or less.

  The negative electrode active material 13 may further include barium sulfate, reinforcing short fibers, and the like. Examples of the reinforcing short fibers include acrylic fibers, polyethylene fibers, polypropylene fibers, and polyethylene terephthalate fibers. The content of barium sulfate may be, for example, 0.5% by mass or more and 3.0% by mass or less based on the total mass of the negative electrode active material. The content of the reinforcing short fiber may be, for example, 0.05% by mass or more and 0.3% by mass or less based on the total mass of the negative electrode active material.

  The lead storage battery 1 described above is suitably used as a lead storage battery for an idling stop system (Start-Stop System) vehicle or a micro hybrid vehicle. That is, one embodiment of the present invention is an application of the above-described lead-acid battery 1 to an idling stop system (Start-Stop System) vehicle or a micro hybrid vehicle.

  The lead storage battery 1 is manufactured by, for example, a manufacturing method including an electrode manufacturing process for obtaining electrodes (a negative electrode and a positive electrode) and an assembly process for obtaining a lead storage battery 1 by assembling components including electrodes.

  In the electrode manufacturing process, for example, after holding the negative electrode active material paste on the negative electrode current collector 12, aging and drying are performed to obtain an unformed negative electrode, and the positive electrode current collector 14 holds the positive electrode active material paste. After that, aging and drying are performed under the above-mentioned conditions to obtain an unformed positive electrode.

  The negative electrode active material paste includes, for example, lead powder, bisphenol-based resin, lignin sulfonic acid (salt), the above-mentioned other components added as needed, a solvent (eg, water or an organic solvent), and sulfuric acid (eg, dilute sulfuric acid). Contains. The negative electrode active material paste is obtained by, for example, obtaining a mixture by mixing lead powder and each component, and then adding a solvent and sulfuric acid to the mixture and kneading the mixture.

The positive electrode active material paste contains, for example, lead powder, the above-mentioned other components added as necessary, a solvent (for example, water or an organic solvent), and sulfuric acid (for example, diluted sulfuric acid). The positive electrode active material paste may further contain lead red (Pb ₃ O ₄ ) from the viewpoint of shortening the formation time.

  As the lead powder, for example, lead powder produced by a ball mill type lead powder production machine or a barton pot type lead powder production machine (in a ball mill type lead powder production machine, a mixture of a main component PbO powder and flaky metal lead) ).

  The aging may be performed in an atmosphere at a temperature of 35 to 85 ° C and a humidity of 50 to 98 RH% for 15 to 60 hours. Drying may be performed at a temperature of 45-80 ° C for 15-30 hours.

  In the assembling process, for example, the obtained unformed negative electrode and positive electrode are laminated via the separator 11, and the lugs 12 a and 14 a of the electrodes of the same polarity are welded with the straps 16 and 17 to obtain an electrode group. This electrode group is arranged in a battery case to produce an unformed lead-acid battery. Next, dilute sulfuric acid to which silica has been added is put into an unformed lead storage battery, and a direct current is applied to form a battery case. Subsequently, the lead storage battery 1 is obtained by adjusting the specific gravity (20 ° C.) of the sulfuric acid after the chemical formation to an appropriate specific gravity of the electrolytic solution. The specific gravity (20 ° C.) of the sulfuric acid used for the formation may be 1.15 to 1.25. The formation conditions can be adjusted according to the size of the electrode. The chemical conversion treatment may be performed in an assembly process or an electrode manufacturing process (tank formation).

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to only the following examples.

<Example 1>
(Preparation of positive electrode)
To the lead powder, 0.25% by mass of acrylic fiber (based on the total mass of the lead powder) was added as a reinforcing short fiber and dry-mixed. Next, 3 mass% of water and 30 mass% of dilute sulfuric acid (specific gravity 1.55) were added to the mixture containing the obtained lead powder, and the mixture was kneaded for 1 hour to prepare a positive electrode active material paste. In preparing the positive electrode active material paste, dilute sulfuric acid (specific gravity 1.55) was added stepwise to avoid a rapid temperature rise. The amounts of water and diluted sulfuric acid are based on the total mass of the lead powder and the reinforcing short fibers.

  The positive electrode active material paste was filled in an expandable current collector produced by subjecting a rolled sheet made of a lead alloy to an expanding process, and then aged at a temperature of 50 ° C. and a humidity of 98% for 24 hours. Thereafter, the resultant was dried at a temperature of 50 ° C. for 16 hours to prepare a positive electrode having an unformed positive electrode active material.

(Preparation of negative electrode)
The bisphenol-based resin includes a first structural unit derived from bisphenol A and a second structural unit derived from bisphenol S, wherein the first structural unit and the second structural unit are 4-aminobenzenesulfonic acid ( A bisphenol-based resin having a group derived from sulfanilic acid) and a group derived from paraformaldehyde was used. The content of the first structural unit is 0.8 mol, the content of the second structural unit is 0.2 mol, the content of the group derived from 4-aminobenzenesulfonic acid is 0.8 mol, and The derived group was 2.25 mol. After adding a mixture of this bisphenol resin, lignin sulfonic acid (salt) (trade name: Vanirex N, manufactured by Nippon Paper Industries Co., Ltd.) and furnace black (trade name: Vulcan XC, manufactured by Cabot Corporation) to lead powder Dry mixed. Next, water was added and kneaded. Subsequently, the mixture was kneaded while adding dilute sulfuric acid having a specific gravity of 1.280 little by little to prepare a negative electrode active material paste. The bisphenol-based resin content was 0.2% by mass, the ligninsulfonic acid (salt) content was 0.1% by mass, and the furnace black content was based on the total mass of the negative electrode active material after chemical formation. 0.2% by mass.

  This negative electrode active material paste was filled in an expandable current collector produced by subjecting a rolled sheet made of a lead alloy to expand processing, and then aged for 24 hours in an atmosphere at a temperature of 50 ° C and a humidity of 98%. Thereafter, drying was performed to produce a negative electrode having an unformed negative electrode active material.

(Battery assembly)
The unformed negative electrode was inserted into a bag-shaped polyethylene separator. Next, five unformed anodes and six unformed anodes inserted in the bag-like separator were alternately laminated. Subsequently, by using a cast-on-strap (COS) method, the lugs of the electrodes of the same polarity were welded to each other to produce an electrode group.

  Six electrode plates were prepared and inserted into a battery case to assemble a 12 V battery K-42 stipulated by the Battery Association of Japan standard SBA S0101. Thereafter, a sulfuric acid solution having a specific gravity of 1.230 was injected, and formation was performed at a constant current of 10.4 A for 20 hours. The specific gravity of the electrolytic solution (sulfuric acid solution) after chemical formation was adjusted to 1.28 (20 ° C.).

<Comparative Example 1>
A lead-acid battery was produced in the same manner as in Example 1, except that no bisphenol-based resin was used in producing the negative electrode.

<Comparative Example 2>
A lead-acid battery was produced in the same manner as in Example 1, except that ligninsulfonic acid (salt) was not used in producing the negative electrode.

<Comparative Example 3>
In producing the negative electrode, instead of the bisphenol-based resin, a structural unit derived from bisphenol A is included (not a structural unit derived from bisphenol S), and the structural unit is derived from 4-aminobenzenesulfonic acid (sulfanilic acid) A lead-acid battery was produced in the same manner as in Example 1 except that a resin having a group derived from paraformaldehyde and a resin derived from paraformaldehyde (trade name: Bispaz P215) was used.

<Comparative Example 4>
A lead-acid battery was produced in the same manner as in Comparative Example 3, except that ligninsulfonic acid (salt) was not used in producing the negative electrode.

[Evaluation of Desorption of Additive in Negative Electrode]
The lead storage battery before chemical formation was disassembled, the negative electrode was taken out, the negative electrode was washed with water for 1 hour, and then dried under vacuum. The negative electrode active material was separated from the dried negative electrode, and 2.0 g of the pulverized powder was added to 20 mL of a mixed solution of glacial acetic acid: hydrogen peroxide = 9: 1 (volume ratio) and dissolved for 1 hour until completely dissolved. The ultrasonic treatment was performed as described above. To this solution, 5 mL of sulfuric acid having a sulfuric acid concentration of 27.5% by mass was added, mixed, allowed to stand for 10 minutes, and then centrifuged. 2 mL of the supernatant was collected, and 10 mL of 5N-NaOH was added. A small amount of MnO ₂ was further added, stirred, and allowed to stand until foaming was completed, thereby removing the hydrogen peroxide solution to obtain a measurement sample.
About the obtained measurement sample, the absorbance was measured using a UV absorbance measuring device (trade name: UV-2450, manufactured by Shimadzu Corporation) under the following conditions, and the absorbance at a wavelength of 292 nm was obtained.
(conditions)
Wavelength range: 200 to 400 nm
Scan speed: Medium sampling pitch: 0.2 nm
Slit width: 1.0 nm
Light source switching wavelength: 360 nm
Measurement mode: single Regarding the negative electrode after chemical formation, a measurement sample was prepared in the same manner as above, and the absorbance at a wavelength of 292 nm was determined. Using the absorbance at 292 nm obtained for the negative electrodes before and after the chemical formation, the residual ratio of the additive was calculated according to the following formula.
Residual rate of additive (%) = (absorbance after chemical formation) / (absorbance before chemical formation) × 100
If the residual ratio of the additive exceeds 50%, it can be said that desorption of the additive can be suppressed. Table 1 shows the results.

[Life of lead-acid battery in low-temperature environment]
For Example 1 and Comparative Example 1 in which desorption of the additive could be suppressed, the life of the lead storage battery under a low-temperature environment was also evaluated according to the procedure of a sulfation acceleration test described below. Table 1 shows the results.

(Sulfation acceleration test)
Test temperature: 10 ° C
With the following (1) to (6) as one cycle, the time when the voltage became lower than 7.2 V was determined as the life.
(1) Constant voltage charge 14V Maximum current 50A 90 seconds (2) Constant current discharge 30A 45 seconds (3) Constant current discharge 250A 0.5 seconds (4) Constant voltage charge 12.85V Maximum current 50A 80 seconds (5) Constant Voltage charging 13.2V Maximum current 50A 40 seconds (6) Constant current discharging 0.2A 1 hour

  DESCRIPTION OF SYMBOLS 1 ... Lead storage battery, 9 ... Negative electrode, 10 ... Positive electrode, 11 ... Separator, 12 ... Negative electrode collector, 13 ... Negative electrode active material.

Claims (3)

Including a positive electrode, a negative electrode, and a separator,
The negative electrode has a current collector and a negative electrode active material held by the current collector,
The negative electrode active material,
A resin having a first structural unit derived from bisphenol A, and a second structural unit derived from bisphenol S;
And a lignin sulfonic acid or a salt thereof.   The lead-acid battery according to claim 1, wherein each of the first structural unit and the second structural unit has a group derived from aminobenzenesulfonic acid or a derivative thereof.   3. The lead-acid battery according to claim 1, wherein each of the first structural unit and the second structural unit has a group derived from formaldehyde or a derivative thereof. 4.

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