JP6728772B2 - Electrode, lead-acid battery and manufacturing method thereof - Google Patents

Description

The present invention relates to a phenolic resin, a resin composition, an electrode, a lead storage battery, and a method for manufacturing these.

Lead-acid batteries for automobiles are widely used for starting an engine and supplying electric power to electric components. In recent years, as an effort to protect the environment and improve fuel efficiency, an idling stop system (hereinafter referred to as "ISS") that stops an engine when a vehicle is temporarily stopped and restarts it when starting is started. In the lead storage battery used in the ISS, the engine is frequently started and stopped repeatedly, so that the number of times of large current discharge at the time of engine start increases, which overlaps with the use of electrical components and the discharge load increases.

Charging of lead acid batteries for automobiles is constant voltage charging by an alternator. In recent years, the set value of the alternator voltage has been decreasing for the purpose of suppressing a decrease in the electrolytic solution due to water decomposition during charging. In addition, in recent years, in addition to adopting such a low charging voltage, by controlling charging by an alternator during running called a power generation control system according to the running state of the vehicle and the charging state of the lead storage battery, , The engine load is reduced, the fuel efficiency is improved, and the CO _{2 is} reduced”. In such a system, it is difficult for the lead storage battery to be charged, and it is difficult for the lead storage battery to be fully charged. Under such usage conditions, lead-acid batteries are often not fully charged and used with excessive discharge.

If the lead storage battery is not completely charged and the state of low charge continues, a phenomenon (sulfation) in which lead sulfate, which is an inactive discharge product, accumulates on electrodes (electrode plate etc.) may occur. In such a situation, it is known that the electrode active material is in a state of being less likely to be reduced (less likely to be charged), so that battery performance such as cycle characteristics is deteriorated.

Further, when it is difficult to completely charge the battery, a stratification phenomenon occurs in which a difference in concentration of dilute sulfuric acid as an electrolytic solution occurs between an upper portion and a lower portion of an electrode (electrode plate or the like) in a lead storage battery. In this case, the concentration of dilute sulfuric acid in the lower part of the electrode becomes high and sulfation occurs. Therefore, the reactivity of the lower part of the electrode is lowered, and only the upper part of the electrode reacts intensively. As a result, deterioration such as weakening of the connection between the electrode active materials progresses, and the electrode active material peels off from the current collector (for example, current collector grid) supporting the electrode active material at the upper part of the electrode, resulting in cycle characteristics. Battery performance such as

On the other hand, as a means for improving cycle characteristics and the like, Patent Document 1 below discloses a technique relating to a negative electrode for a lead storage battery obtained by using a negative electrode active material and a condensate of phenols, aminobenzenesulfonic acid and formaldehyde. It is disclosed.

International Publication No. 1997/37393

By the way, it is required for lead-acid batteries to further improve battery performance such as cycle characteristics.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a phenolic resin having excellent cycle characteristics in a lead storage battery and a method for producing the same. Another object of the present invention is to provide a resin composition containing the phenolic resin. A further object of the present invention is to provide an electrode containing the phenolic resin and a method for manufacturing the same. An object of the present invention is to provide a lead storage battery including the electrode and a method for manufacturing the same.

As a result of intensive studies by the present inventors, it has been clarified that sufficient cycle characteristics cannot be obtained when the negative electrode for a lead storage battery described in Patent Document 1 is used. On the other hand, the present inventors have found that at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives, at least one selected from the group consisting of urea and urea derivatives, and the group consisting of formaldehyde and formaldehyde derivatives. It has been found that the above problems can be solved by using a phenolic resin obtained by reacting with at least one selected.

That is, the phenolic resin according to the present invention includes (a) at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives, and (b) at least one selected from the group consisting of urea and urea derivatives, c) It has a structural unit derived from the reaction of at least one selected from the group consisting of formaldehyde and formaldehyde derivatives.

The phenolic resin according to the present invention makes it possible to obtain excellent cycle characteristics in a lead storage battery. Moreover, according to the phenolic resin of the present invention, excellent battery performance such as charge acceptability, discharge characteristics and cycle characteristics can be achieved.

As to the factor of obtaining excellent cycle characteristics as described above, in the lead storage battery obtained by using the phenolic resin according to the present invention, it is suppressed that the reaction product generated in the electrode reaction of the lead storage battery is coarsened. It is speculated that this is because the specific surface area of the electrode is kept high. However, the factor is not limited to this.

The weight average molecular weight of the phenolic resin according to the present invention is preferably 500 to 100,000. In this case, cycle characteristics are likely to be improved.

The resin composition according to the present invention contains the phenolic resin according to the present invention. Also in the resin composition according to the present invention, excellent cycle characteristics can be obtained.

The pH of the resin composition according to the present invention is preferably 6.0 to 14.0.

The electrode according to the present invention includes an electrode active material and the phenolic resin according to the present invention. The lead acid battery according to the present invention includes the electrode according to the present invention. Also in these cases, excellent cycle characteristics can be obtained.

The method for producing a phenolic resin according to the present invention comprises (a) at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives, and (b) at least one selected from the group consisting of urea and urea derivatives, (C) A step of reacting with at least one selected from the group consisting of formaldehyde and a formaldehyde derivative.

According to the method for producing a phenolic resin according to the present invention, it is possible to obtain a phenolic resin having excellent cycle characteristics in a lead storage battery. Further, according to the method for producing a phenolic resin according to the present invention, it is possible to obtain a phenolic resin capable of satisfying both battery performance such as excellent charge acceptability, discharge characteristics and cycle characteristics.

In the method for producing a phenolic resin according to the present invention, the blending amount of the component (b) is 0.50 to 5.00 mol relative to 1.00 mol of the component (a), and the blending amount of the component (c) is A preferred mode is 1.50 to 9.00 mol in terms of formaldehyde with respect to 1.00 mol of the component (a). In this case, more excellent cycle characteristics can be obtained.

The method for producing an electrode according to the present invention includes a step of producing an electrode using the phenolic resin obtained by the method for producing a phenolic resin according to the present invention. A method of manufacturing a lead storage battery according to the present invention includes a step of obtaining an electrode by the method of manufacturing an electrode according to the present invention. Also in these cases, excellent cycle characteristics can be obtained.

According to the present invention, excellent cycle characteristics can be obtained in a lead storage battery. Further, according to the present invention, it is possible to achieve both excellent battery acceptability, discharge characteristics, cycle characteristics, and other battery performance. According to the present invention, it is possible to provide an application of a phenolic resin to a lead storage battery and an application of a resin composition containing a phenolic resin to a lead storage battery.

Particularly, according to the present invention, excellent characteristics can be obtained in a lead storage battery having a negative electrode containing the phenolic resin. According to the present invention, it is possible to provide an application of a phenolic resin to a negative electrode of a lead storage battery and an application of a resin composition containing a phenolic resin to a negative electrode of a lead storage battery.

According to the present invention, it is possible to provide an application of a phenolic resin to a lead storage battery in an automobile, and an application of a resin composition containing a phenolic resin to a lead storage battery in an automobile. Further, according to the present invention, since the decrease in charging capacity is extremely small, it is possible to provide a lead storage battery that is sufficiently satisfactory for use in an ISS vehicle used in a harsh environment. According to the present invention, it is possible to provide an application of a phenolic resin to a lead storage battery in an ISS vehicle, and an application of a resin composition containing a phenolic resin to a lead storage battery in an ISS vehicle. According to the present invention, it is possible to provide the application of the lead storage battery to the ISS vehicle.

FIG. 1 is a perspective view showing an example of a lead storage battery. FIG. 2 is a diagram showing a part of the internal structure of the lead storage battery shown in FIG. 1. FIG. 3 is a perspective view showing an example of the electrode plate group. FIG. 4 is a diagram showing measurement results of ¹ H-NMR spectrum.

In the present specification, the numerical range indicated by using "to" indicates a range including the numerical values before and after "to" as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present specification, the upper limit value or the lower limit value of the numerical range of one stage may be replaced with the upper limit value or the lower limit value of the numerical range of another stage. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the value shown in the examples. “A or B” may include either one of A and B, or may include both. Unless otherwise specified, the materials exemplified in the present specification can be used alone or in combination of two or more kinds. In the present specification, the content of each component in the composition is the total amount of the plurality of substances present in the composition, unless a plurality of substances corresponding to each component are present in the composition. Means

Hereinafter, embodiments of the present invention will be described in detail.

<Phenolic resin, resin composition and production method thereof>
The phenolic resin according to the present embodiment includes (a) at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives (hereinafter, sometimes referred to as “(a) component”), and (b) urea and urea. At least one selected from the group consisting of derivatives (hereinafter sometimes referred to as "(b) component") and at least one selected from the group consisting of (c) formaldehyde and formaldehyde derivatives (hereinafter sometimes referred to as "(c) component") , And a structural unit derived from the reaction of the components (a), (b) and (c). The resin composition according to this embodiment contains the phenolic resin according to this embodiment. The resin composition according to this embodiment is a liquid resin solution at 25° C., for example. Hereinafter, components for obtaining the phenolic resin, constituent components of the resin composition, and the like will be described.

(Component (a): phenolsulfonic acid and phenolsulfonic acid derivative)
Phenolsulfonic acid is a compound having a hydroxyl group bonded to the benzene ring (phenolic hydroxyl groups) and a sulfo group (-SO 3 _H). A plurality of each of the hydroxyl group and the sulfo group may be bonded to the benzene ring.

Examples of the phenolsulfonic acid include 4-hydroxybenzenesulfonic acid, 2-hydroxybenzenesulfonic acid, 2,5-dihydroxybenzenesulfonic acid, and 4,5-dihydroxybenzene-1,3-disulfonic acid. As the phenolsulfonic acid, at least one selected from the group consisting of 4-hydroxybenzenesulfonic acid and 2-hydroxybenzenesulfonic acid is preferable, and 4-hydroxybenzenesulfonic acid is more preferable, from the viewpoint of further excellent discharge characteristics and cycle characteristics. ..

Examples of the phenolsulfonic acid derivative include a compound in which at least one hydrogen atom of the benzene ring of phenolsulfonic acid is substituted, and a hydrogen atom of at least one sulfo group of phenolsulfonic acid (4-hydroxybenzenesulfonic acid, etc.) Examples thereof include metal salts in which is substituted with an alkali metal (monoalkali metal salt or the like) or an alkaline earth metal.

Examples of the substituent that substitutes the hydrogen atom of the benzene ring include an alkoxy group (methoxy group and the like) and a carboxy group. Examples of the compound in which the hydrogen atom of the benzene ring of phenolsulfonic acid is substituted include 4-hydroxy-3-methoxybenzenesulfonic acid and 2-hydroxy-5-sulfobenzoic acid.

Examples of alkali metals include sodium and potassium. Examples of alkaline earth metals include magnesium and calcium. The metal salt is preferably at least one selected from the group consisting of sodium salt and potassium salt, and more preferably sodium salt, from the viewpoint of well-balanced improvement in charge acceptability, discharge characteristics and cycle characteristics.

The phenolsulfonic acid and the phenolsulfonic acid derivative may be hydrates. As the component (a), one type can be used alone, or two or more types can be used in combination. You may use together phenol sulfonic acid and a phenol sulfonic acid derivative.

(Component (b): urea and urea derivative)
Examples of the urea derivative include monomethylol urea, dimethylol urea, alkoxymethylene urea, N-alkoxymethylene urea, and methylene diurea. As the component (b), one type can be used alone, or two or more types can be used in combination. You may use together urea and a urea derivative. As the component (b), at least one selected from the group consisting of urea, monomethylol urea, and dimethylol urea is preferable, and urea is more preferable, from the viewpoint of further excellent discharge characteristics and cycle characteristics.

The blending amount of the component (b) for obtaining the phenolic resin is 0.30 mol or more with respect to 1.00 mol of the component (a) from the viewpoint of well-balanced improvement in charge acceptability, discharge characteristics and cycle characteristics. Is preferable, 0.40 mol or more is more preferable, and 0.50 mol or more is further preferable. The blending amount of the component (b) may be 1.00 mol or more, 1.50 mol or more, or 2.00 mol or more with respect to 1.00 mol of the component (a). Or 2.50 mol or more. The blending amount of the component (b) is preferably 7.00 mol or less, and 6.50 mol, relative to 1.00 mol of the component (a), from the viewpoint of well-balanced improvement in charge acceptability, discharge characteristics and cycle characteristics. The following is more preferable, 6.00 mol or less is still more preferable, 5.50 mol or less is particularly preferable, 5.00 mol or less is extremely preferable, 4.50 mol or less is very preferable, and 4.00 mol or less is still more preferable. preferable.

(Component (c): formaldehyde and formaldehyde derivative)
As the formaldehyde, formaldehyde in formalin (for example, a 37% by mass formaldehyde aqueous solution) may be used. Examples of formaldehyde derivatives include paraformaldehyde, hexamethylenetetramine, and trioxane. As the component (c), one type can be used alone, or two or more types can be used in combination. You may use formaldehyde and a formaldehyde derivative together.

As the component (c), a formaldehyde derivative is preferable, and paraformaldehyde is more preferable, from the viewpoint of easily obtaining excellent cycle characteristics. Paraformaldehyde has, for example, a structure represented by the following general formula (I).
HO(CH ₂ O) _n1 H (I)
[In Formula (I), n1 shows the integer of 2-100. ]

From the viewpoint of improving the reactivity of the component (b), the compounding amount of the component (c) in terms of formaldehyde for obtaining the phenolic resin is 1.50 mol or more relative to 1.00 mol of the component (a). It is preferably 2.00 mol or more, more preferably 2.20 mol or more, still more preferably 2.40 mol or more, particularly preferably 2.50 mol or more, and most preferably 2.60 mol or more. The amount of component (c) converted to formaldehyde may be 3.00 mol or more, or 4.00 mol or more, and 5.00 mol with respect to 1.00 mol of component (a). It may be more than. From the viewpoint of excellent solubility of the resulting phenolic resin in a solvent, the amount of component (c) converted to formaldehyde is preferably 10.50 mol or less relative to 1.00 mol of component (a), and 10. It is more preferably not more than 00 mol, further preferably not more than 9.50 mol, particularly preferably not more than 9.00 mol, very preferably not more than 8.00 mol, very preferably not more than 7.00 mol, very preferably not more than 6.00 mol Even more preferable.

The phenolic resin preferably has, for example, a structural unit represented by the following formula (II).

［式（ＩＩ）中、Ｒ^２１は、アルカリ金属又は水素原子を示す。Ｒ^２２及びＲ^２３は、メチロール基（−ＣＨ_２ＯＨ）又は水素原子を示し、互いに同一であっても異なってもよい。Ｒ^２４は、アルカリ金属又は水素原子を示す。ｎ２１は、１〜２００の整数を示し、ｎ２２は、１〜１０００の整数を示し、ｎ２３は、１〜３の整数を示す。］

[In the formula (II), R ²¹ represents an alkali metal or a hydrogen atom. R ²² and R ²³ represent a methylol group (—CH ₂ OH) or a hydrogen atom, and may be the same or different from each other. R ²⁴ represents an alkali metal or hydrogen atom. n21 shows the integer of 1-200, n22 shows the integer of 1-1000, and n23 shows the integer of 1-3. ]

Examples of the alkali metal for R ²¹ and R ²⁴ include sodium and potassium. n21 is preferably an integer of 5 to 100 from the viewpoint of further excellent cycle characteristics and solubility in a solvent. n22 is preferably an integer of 1 to 500 from the viewpoint of further excellent cycle characteristics and the excellent storage stability of the resin. n23 varies depending on manufacturing conditions, but is preferably 1 or 2.

The weight average molecular weight of the phenolic resin is preferably 500 or more, more preferably 750 or more, and more preferably 1000 or more from the viewpoint that cycle characteristics are easily improved by suppressing the phenolic resin from eluting from the electrode into the electrolytic solution in the lead storage battery. The above is more preferable. The weight average molecular weight of the phenolic resin is preferably 100,000 or less, more preferably 75,000 or less, from the viewpoint that cycle characteristics are easily improved by suppressing a decrease in the adsorptivity to the electrode active material and a decrease in the dispersibility. It is more preferably 50,000 or less.

The weight average molecular weight of the phenolic resin can be measured, for example, by gel permeation chromatography (hereinafter, referred to as “GPC”) under the following conditions.
(GPC condition)
Device: High Performance Liquid Chromatograph LC-2200 Plus (manufactured by JASCO Corporation)
Pump: PU-2080
Differential Refractometer: RI-2031
Detector: UV-visible absorptiometer UV-2075 (λ: 254 nm)
Column oven: CO-2065
Column: GF-1G7B+GF-7MHQ×2 (manufactured by Showa Denko KK)
Column temperature: 40°C
Eluent: solution containing LiBr (20 mM) and triethylamine (400 mM) in a mixture of methanol and pure water so that the content of methanol was 40% by volume 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: 1.06×10 ² ; manufactured by Kishida Chemical Co., Ltd.), dibutylhydroxytoluene (molecular weight: 2.20×10 ² ; (Manufactured by Kishida Chemical Co., Ltd.)

The method for producing a phenolic resin according to this embodiment includes, for example, a resin production step of reacting the components (a), (b) and (c) to obtain a phenolic resin. The resin composition according to the present embodiment may be a composition obtained in the resin manufacturing process, or may be a composition obtained by mixing the phenolic resin and other components after the resin manufacturing process.

The phenolic resin can be obtained, for example, by reacting the components (a), (b) and (c) in a reaction solvent. The reaction solvent is preferably water (for example, ion-exchanged water). An organic solvent, a catalyst, an additive or the like may be used to accelerate the reaction.

In the resin production process, from the viewpoint of further improving the cycle characteristics, the blending amount of the component (b) is 0.30 to 7.00 mol with respect to 1.00 mol of the component (a), and the component (c). It is preferable that the compounding amount is 1.50 to 10.50 mol in terms of formaldehyde with respect to 1.00 mol of the component (a). The preferred blending amounts of the component (b) and the component (c) are in the ranges described above for the blending amounts of the component (b) and the component (c), respectively.

The phenolic resin is preferably obtained by reacting the components (a), (b) and (c) under basic conditions (alkaline conditions) from the viewpoint of easily obtaining a sufficient amount of phenolic resin. A basic compound may be used to adjust to basic conditions. Examples of the basic compound include sodium hydroxide, potassium hydroxide and calcium hydroxide. The basic compounds may be used alone or in combination of two or more. Among the basic compounds, at least one selected from the group consisting of sodium hydroxide and potassium hydroxide is preferable from the viewpoint of excellent reactivity.

When the reaction solution containing the component (a), the component (b) and the component (c) is neutral (pH=7.0) at the start of the reaction, the production reaction of the phenolic resin may be difficult to proceed. When the reaction solution is acidic (pH<7.0), a side reaction may proceed. Therefore, the pH of the reaction solution at the start of the reaction is preferably alkaline (exceeds 7.0) from the viewpoint of suppressing the progress of the side reaction while promoting the reaction of forming the phenolic resin. 1 or more is more preferable, 7.5 or more is further preferable, and 8.0 or more is particularly preferable. The pH of the reaction solution is preferably 12.0 or less, more preferably 11.0 or less, and 10.0 or less from the viewpoint of suppressing the progress of the hydrolysis of the group derived from the component (b) of the phenolic resin. Is more preferable. The pH of the reaction solution can be measured, for example, by Twin pH manufactured by As One Co., Ltd. pH is defined as the pH at 25°C.

Since it is easy to adjust the pH as described above, the amount of the strongly basic compound is preferably 1.03 mol or more, and 1.05 mol, relative to 1.00 mol of the sulfo group contained in the component (a). The above is more preferable, and 1.10 mol or more is still more preferable. Examples of the strongly basic compound include sodium hydroxide and potassium hydroxide.

The synthesis reaction of the phenolic resin may be carried out by reacting the components (a), (b) and (c) to obtain the phenolic resin, and for example, the components (a), (b) and (c). The components may be reacted at the same time, or two components out of the components (a), (b) and (c) may be reacted and then the remaining one component may be reacted.

The synthesis reaction of the phenolic resin is preferably performed as follows. After charging a solvent (water and the like) and a basic compound (for example, a strongly basic compound), the mixture is stirred at room temperature for 5 to 30 minutes. The component (c) is added thereto, and the mixture is stirred at room temperature for 5 to 30 minutes until the mixture becomes a transparent homogeneous system. A phenol resin is obtained by adding the component (a) and the component (b) to the mixture and conducting a condensation reaction. The temperature of the reaction system is preferably 80° C. or higher, more preferably 85° C. or higher, still more preferably 95° C. or higher, from the viewpoint of excellent reactivity of the components (a), (b) and (c). The temperature of the reaction system is preferably 120° C. or lower, more preferably 115° C. or lower, from the viewpoint of suppressing the evaporation of the reaction solvent (for example, water). The reaction time is, for example, 1 to 8 hours.

The reaction product thus obtained can be dried to remove the solvent (such as water) and the unreacted component (c). Examples of the drying method include freeze drying, vacuum drying, spray drying and heat drying. As a drying method, from the viewpoint of treating a large amount of phenolic resin quickly, heat drying and spray drying are preferable, from the viewpoint of reducing heat stress, and maintaining the shape of the dried phenolic resin in a highly fluid spherical shape. From the viewpoint, spray drying is more preferable.

The particle size of the phenolic resin (phenolic resin or the like obtained by spray drying) is preferably in the following range. The particle size of the phenol resin is from the viewpoint of easily scattering and being electrostatically charged during handling and suppressing the adhesion to the surroundings, and from the viewpoint of suppressing the occurrence of mamako when dissolved in water and improving the handleability. 1 μm or more is preferable, 10 μm or more is more preferable, and 20 μm or more is further preferable. The particle size of the phenolic resin is preferably 1000 μm or less, more preferably 500 μm or less, still more preferably 250 μm or less, from the viewpoint of ensuring sufficient solubility in water. From these viewpoints, the particle size of the phenolic resin is preferably 1 to 1000 μm, more preferably 100 to 500 μm, still more preferably 20 to 250 μm. When the particle diameter of the phenolic resin is 20 to 250 μm, the handleability when kneading with the lead powder is excellent.

The content of the phenolic resin in the electrode layer is preferably 0.01 to 2.0 mass%, more preferably 0.05 to 1.0 mass%, and 0.1 to 2.0 mass% based on the total mass of the electrode active material. 0.5% by mass is more preferable.

The resin composition according to this embodiment may further contain a solvent. Examples of the solvent include water (for example, ion-exchanged water) and an organic solvent. The solvent contained in the resin composition may be the reaction solvent used to obtain the phenolic resin.

The resin composition according to the present embodiment may further contain a natural resin or a synthetic resin other than the phenol resin.

The content of the phenolic resin in the resin composition according to the present embodiment is 80% by mass based on the total mass of the non-volatile components in the resin composition from the viewpoint that charge acceptability, discharge characteristics and cycle characteristics are improved in a well-balanced manner. The above is preferable, 85 mass% or more is more preferable, and 90 mass% or more is still more preferable.

The content of the unreacted component (c) (residual (c) component) in the resin composition according to the present embodiment is 1.0 based on the total mass of the resin composition from the viewpoint of further improving cycle characteristics. It is preferably at most% by mass, more preferably at most 0.9% by mass, still more preferably at most 0.8% by mass. The content of the unreacted component (c) can be reduced, for example, by drying the resin composition. The content of the unreacted component (c) can be measured, for example, by gas chromatography.

From the viewpoint of excellent quality control and operability, the water content of the resin composition according to the present embodiment is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and further preferably 1.0% by mass or more. preferable. From the same viewpoint, the water content is preferably 10.0% by mass or less, more preferably 8.0% by mass or less, and further preferably 5.0% by mass or less. The water content can be measured, for example, by Karl Fischer titration.

The pH of the resin composition is excellent in the solubility of the phenolic resin in the solvent (water, etc.) and the wettability of the resin composition with the electrode active material (lead, lead oxide, etc.) in the battery manufacturing process described later. From the viewpoint of superiority, 6.0 or higher is preferable, 7.0 or higher is more preferable, and 7.0 or higher is further preferable. The pH of the resin composition is preferably 6.0 or more from the viewpoint of further excellent solubility of the phenolic resin in a solvent (water or the like). The pH of the resin composition is preferably 6.0 or more from the viewpoint of further excellent wettability of the resin composition with electrode active materials (lead, lead oxide, etc.). The pH of the resin composition is preferably 14.0 or less, more preferably 13.0 or less, still more preferably 12.0 or less, from the viewpoint of reducing the hydrolysis of the group derived from the component (b) of the phenolic resin. 11.0 or less is particularly preferable. The pH of the resin composition is preferably 11.0 or less from the viewpoint of further excellent wettability of the resin composition with electrode active materials (lead, lead oxide, etc.). In particular, the pH of an aqueous solution containing 5% by mass of a phenolic resin (for example, an aqueous solution containing ion-exchanged water) is preferably within the above range. When the composition obtained in the resin production process is used as the resin composition, the pH of the resin composition is preferably in the above range. The pH of the resin composition can be measured by, for example, Twin pH manufactured by AS ONE CORPORATION. pH is defined as the pH at 25°C. The pH of the resin composition can be adjusted using, for example, a 10 mass% sodium hydroxide aqueous solution.

<Electrodes, lead-acid batteries and manufacturing methods thereof>
The electrode according to the present embodiment is manufactured using the phenolic resin according to the present embodiment, and includes the electrode active material and the phenolic resin according to the present embodiment. Further, the electrode according to this embodiment may be manufactured using the resin composition containing the phenolic resin according to this embodiment. The method of manufacturing an electrode according to this embodiment includes a step of manufacturing an electrode using the phenolic resin obtained by the method of manufacturing a phenolic resin according to this embodiment.

When the electrode is unformed, the electrode has, for example, an electrode layer containing a raw material of an electrode active material (a negative electrode active material or a positive electrode active material) and a current collector supporting the electrode layer. The electrode after chemical formation has, for example, an electrode layer containing an electrode active material (negative electrode active material or positive electrode active material) and the like, and a current collector supporting the electrode layer. The electrode is, for example, a negative electrode (negative electrode plate or the like) for a lead storage battery.

The negative electrode active material can be obtained by aging and drying a negative electrode paste containing a raw material of the negative electrode active material to obtain an unformed negative electrode active material and then forming the unformed negative electrode active material. The negative electrode active material after chemical conversion preferably contains porous spongy lead. The positive electrode active material can be obtained by aging and drying a positive electrode paste containing a raw material of the positive electrode active material to obtain an unformed positive electrode active material and then forming the unformed positive electrode active material. The positive electrode active material after chemical conversion contains lead dioxide, for example.

The lead storage battery according to the present embodiment includes the electrode according to the present embodiment. Examples of the lead storage battery according to the present embodiment include a liquid lead storage battery and a sealed lead storage battery, and a liquid lead storage battery is preferable.

FIG. 1 is a perspective view showing an example of a lead storage battery. The lead storage battery 1 shown in FIG. 1 is a liquid lead storage battery. FIG. 2 is a diagram showing a part of the internal structure of the lead storage battery 1. The lead storage battery 1 is provided with a battery case 2 having an upper surface opened to accommodate a plurality of electrode plate groups 11, and a lid 3 closing the opening of the battery case 2. The lid 3 includes, for example, a positive electrode terminal 4, a negative electrode terminal 5, and a liquid port plug 6 that closes a liquid injection port provided in the lid 3. An electrolytic solution (not shown) is stored in the battery case 2.

The electrode plate group includes separators and positive electrode plates and negative electrode plates that are alternately stacked with the separators in between. FIG. 3 is a perspective view showing an example of the electrode plate group. As shown in FIGS. 2 and 3, the electrode plate group 11 includes, for example, a positive electrode plate 12, a negative electrode plate 13, a bag-shaped separator 14, a positive electrode side strap 15, a negative electrode side strap 16, and an inter-cell connection. It has a part 17 and a pole 18. On the upper peripheral portions of the positive electrode plate 12 and the negative electrode plate 13, current collecting portions 22 and 32 called ear portions are provided.

The method of manufacturing a lead storage battery according to the present embodiment includes, for example, an electrode manufacturing step of obtaining an electrode by the method of manufacturing an electrode according to the present embodiment, and an assembly step of assembling a component member including the electrode to obtain a lead storage battery. There is.

In the electrode manufacturing process, for example, after filling the current collector (for example, current collector grid) with the electrode paste, aging and drying are performed to obtain an unformed electrode. The electrode paste contains, for example, a resin composition containing a phenolic resin as a dispersant, and further contains a raw material of an electrode active material, additives and the like. When the electrode is a negative electrode, the raw material of the negative electrode active material is preferably lead powder (for example, a mixture of PbO powder and scaly metallic lead). Examples of the additive include barium sulfate, a carbon material, and reinforcing short fibers (acrylic fiber, polyethylene fiber, polypropylene fiber, polyethylene terephthalate fiber, carbon fiber, etc.). Examples of the carbon material include carbon black and graphite. Examples of carbon black include furnace black, channel black, acetylene black, thermal black and Ketjen black.

When the electrode according to the present embodiment is a negative electrode, the negative electrode paste is obtained, for example, by adding dilute sulfuric acid to a mixture obtained by adding an additive (phenolic resin or the like) to lead powder and kneading. You can

When barium sulfate, a carbon material or a phenolic resin is used in the negative electrode paste, the content of each component is preferably within the following range. The content of barium sulfate is preferably 0.01 to 1.0 mass% based on the total mass of the raw material (lead powder or the like) of the negative electrode active material. The content of the carbon material is preferably 0.2 to 1.4 mass% based on the total mass of the raw material (lead powder or the like) of the negative electrode active material. The content of the phenolic resin (resin solid content) according to the present embodiment is preferably 0.01 to 2.0 mass% based on the total mass of the raw materials (lead powder etc.) of the negative electrode active material, and 0.05 ˜1.0% by mass is more preferable, and 0.1 to 0.5% by mass is further preferable.

Examples of the material of the current collector include lead alloys such as lead-calcium-tin alloy and lead-antimony-arsenic alloy. Selenium, silver, bismuth, etc. may be added to the current collector as appropriate depending on the application. A current collector can be obtained by forming these lead alloys in a grid shape by a gravity casting method, an expanding method, a punching method or the like.

As aging conditions, a temperature of 35 to 85° C. and a humidity of 50 to 98 RH% for 15 to 60 hours are preferable. The drying conditions are preferably 45 to 80° C. and 15 to 30 hours.

The positive electrode (positive electrode plate or the like) for a lead storage battery can be obtained, for example, by the following method. First, short fibers for reinforcement are added to lead powder (PbO) which is a raw material of the electrode active material, and then water and dilute sulfuric acid are added. This is kneaded to produce a positive electrode paste. In producing the positive electrode paste, lead tin (Pb ₃ O ₄ ) may be added from the viewpoint of shortening the formation time. An unformed positive electrode is obtained by filling the current collector (current collector grid or the like) with this positive electrode paste and then aging and drying. In the positive electrode paste, the content of the reinforcing short fibers is preferably 0.005 to 0.3 mass% based on the total mass of the raw materials (lead powder or the like) of the positive electrode active material. The type of current collector, aging conditions and drying conditions are almost the same as those for the negative electrode.

In the assembly process, for example, the unformed negative electrodes and positive electrodes produced as described above are alternately laminated with separators interposed, and electrodes of the same polarity (electrode plates, etc.) are connected (welded, etc.) with straps to form electrodes. Obtain a group (electrode group, etc.). This electrode group is placed in a battery case to prepare an unformed battery. Next, a lead-acid battery is obtained by pouring dilute sulfuric acid into an unformed battery and then applying a direct current to carry out the formation. Alternatively, the electrolytic solution (dilute sulfuric acid) may be injected after the dilute sulfuric acid has been removed. The specific gravity (20° C. conversion) of the electrolytic solution (dilute sulfuric acid) is preferably 1.25 to 1.35.

Examples of the material of the separator include polyethylene and glass fiber. The chemical conversion conditions and the specific gravity of the electrolytic solution (dilute sulfuric acid) can be adjusted according to the properties of the electrode active material, the size of the electrode, and the like. Further, the chemical conversion treatment is not limited to being performed in the assembly process, and may be performed in the electrode manufacturing process.

<Car>
The vehicle according to the present embodiment includes the lead storage battery according to the present embodiment. Examples of the automobile according to the present embodiment include an ISS vehicle.

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

<Preparation of negative electrode plate>
[Example 1]
After adding 4.8 parts by mass of sodium hydroxide and 279.5 parts by mass of pure water to a reaction vessel equipped with a Dimroth, a mechanical stirrer and a thermometer, the mixture was stirred at 150 rpm for 10 minutes to prepare an aqueous sodium hydroxide solution. To this aqueous solution was added 39.3 parts by mass of paraformaldehyde (in terms of formaldehyde), and the mixture was stirred for 10 minutes to dissolve paraformaldehyde and obtain a uniform aqueous solution. To this aqueous solution, 69.6 parts by mass of sodium 4-hydroxybenzenesulfonate dihydrate and 45.0 parts by mass of urea were added. Then, the temperature in the reaction system was set to 95° C. using an oil bath set to 115° C., and the mixture was stirred for 6 hours while heating. Thereby, a phenolic resin was obtained.

The pH at the start of the reaction immediately after adding urea was measured under the following measurement conditions.
(PH measurement conditions)
Testing machine: Twin pH (manufactured by As One Co., Ltd.)
Calibration solution: pH 6.86 (25°C), pH 4.01 (25°C)
Measurement temperature: 25°C
Measurement procedure: Two-point calibration was performed using a calibration solution. After washing the sensor part of the tester, the measurement solution was sucked with a dropper, and 0.1 to 0.3 mL was dropped on the sensor part. The pH when the indication of the end of measurement appeared on the screen was taken as the measured value.

The weight average molecular weight of the phenolic resin obtained in Example 1 was measured by GPC under the following conditions. The weight average molecular weight measured by GPC was 10,000.

(GPC condition)
Device: High Performance Liquid Chromatograph LC-2200 Plus (manufactured by JASCO Corporation)
Pump: PU-2080
Differential Refractometer: RI-2031
Detector: UV-visible absorptiometer UV-2075 (λ: 254 nm)
Column oven: CO-2065
Column: GF-1G7B+GF-7MHQ×2 (manufactured by Showa Denko KK)
Eluent: solution containing LiBr (20 mM) and triethylamine (400 mM) in a mixture of methanol and pure water so that the content of methanol was 40% by volume 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: 1.06×10 ² ; manufactured by Kishida Chemical Co., Ltd.), dibutylhydroxytoluene (molecular weight: 2.20×10 ² ; (Manufactured by Kishida Chemical Co., Ltd.)

The phenolic resin obtained in Example 1 was isolated by low temperature drying (40° C.) under reduced pressure, and ¹ H-NMR spectrum was measured under the following conditions. The measurement result of the ¹ H-NMR spectrum is shown in FIG. 4.
Device: ECX400II (made by JEOL RESONANCE Co., Ltd.)
Heavy solvent: D ₂ O

The pH of the aqueous solution containing 5% by mass of the phenolic resin obtained in Example 1 was measured under the same measurement conditions as the above-mentioned measurement conditions of pH at the start of the reaction.

Phenolic resin 0.2% by mass, furnace black 0.2% by mass, and barium sulfate 1.0% by mass were added to the lead powder and then dry-mixed (compounding amount standard: total mass of lead powder). ). Next, a negative electrode paste was prepared by kneading while adding dilute sulfuric acid (specific gravity 1.26 (converted at 20° C.)) and water. The negative electrode paste was filled in an expanded current collector (lead-calcium-tin alloy) having a thickness of 0.6 mm to prepare a negative electrode plate. The negative electrode plate was allowed to stand for 18 hours in an atmosphere of a temperature of 50° C. and a humidity of 95% according to a usual method to be aged, and then dried in an atmosphere of a temperature of 50° C. to obtain an unformed negative electrode plate.

[Examples 2 to 4]
A negative electrode plate was obtained in the same manner as in Example 1 except that the components for obtaining the phenolic resin were changed to those in Table 1. Further, as in Example 1, the weight average molecular weight of the phenolic resin, the pH at the start of the reaction, and the pH of the aqueous solution containing 5% by mass of the phenolic resin were measured. In addition, in Table 1, the blending amount of paraformaldehyde is a blending amount in terms of formaldehyde.

[Comparative Example 1]
A negative electrode plate was obtained in the same manner as in Example 1 except that the phenolic resin was not used.

[Comparative example 2]
A negative electrode plate was obtained in the same manner as in Example 1 except that the components for obtaining the phenolic resin were changed to those in Table 1. Further, as in Example 1, the weight average molecular weight of the phenolic resin, the pH at the start of the reaction, and the pH of the aqueous solution containing 5% by mass of the phenolic resin were measured. In Table 1, the compounding amount of 37 mass% formalin is a compounding amount in terms of formaldehyde.

<Preparation of positive electrode plate>
0.01% by mass (reference: total mass of lead powder) of reinforcing short fibers (polyethylene fiber) was added to the lead powder and then dry mixed. Next, diluted sulfuric acid (specific gravity 1.26 (converted at 20° C.)) and water were added and kneaded to prepare a positive electrode paste. A positive electrode current collector (lead-calcium-tin alloy) composed of a cast grid was filled with the positive electrode paste, and the positive electrode plate was left standing for 18 hours in an atmosphere of a temperature of 50° C. and a humidity of 95%, followed by aging at a temperature of It was dried in an atmosphere of °C to obtain an unformed positive electrode plate.

<Battery assembly>
An unformed negative electrode plate was inserted into a polyethylene separator processed into a bag shape. Next, 6 unformed negative electrode plates and 5 unformed positive electrode plates are stacked so that the unformed positive electrode plates and the unformed negative electrode plates inserted in the bag-shaped separator are alternately laminated. Were laminated. Then, the ears of the polar plates having the same polarity were welded together by a cast-on-strap (COS) method to prepare a polar plate group. The electrode group was inserted into a battery case to assemble a 2V single cell battery. Dilute sulfuric acid (specific gravity: 1.28 (converted at 20° C.)) was poured into this battery, and then the mixture was subjected to chemical formation in a water tank at 50° C. for 15 hours at an energizing current of 1.0 A. Then, after discharging the dilute sulfuric acid, a dilute sulfuric acid having a specific gravity of 1.28 (converted at 20° C.) was injected again to obtain a lead storage battery.

<Evaluation of battery characteristics>
The charge acceptability, discharge characteristics and cycle characteristics of the above 2V single cell battery were measured as follows. The measurement results of the charge acceptability, discharge characteristics and cycle characteristics of Comparative Example 2 were set to 100, and the respective characteristics were relatively evaluated. The results are shown in Table 1.

(Charge acceptability)
In terms of charge acceptability, the state of charge (State of charge) of the battery is 90% (that is, at a 5-hour rate current value relative to the rated capacity, 10% of the battery capacity is discharged from the fully charged state). The battery was charged at a constant voltage of 25° C. and 2.333 V, and the current value was measured 5 seconds after the start of charging. It is evaluated that the larger the current value after 5 seconds, the higher the initial charge capacity and the higher the charge acceptability.

(Discharge characteristics)
As discharge characteristics, a battery in a fully charged state that has been left for 16 hours or more in an atmosphere of -15°C is discharged at a constant current at room temperature (25°C) at 5C, and the discharge duration until the battery voltage reaches 1.0V. Was measured. The longer the discharge duration is, the better the discharge characteristics of the battery are evaluated. The C is a relative representation of the magnitude of the current when the rated capacity is discharged with a constant current from the fully charged state. The C means “discharge current value (A)/battery capacity (Ah)”. For example, the current that can discharge the rated capacity in 1 hour is expressed as "1C", and the current that can be discharged in 2 hours is expressed as "0.5C".

(Cycle characteristics)
The cycle characteristics were evaluated by the method according to the Japanese Industrial Standard light load life test (JIS D 5301). It is evaluated that the higher the cycle number, the higher the durability of the battery.

In the example, it can be confirmed that the charge acceptability is greatly improved as compared with the comparative example 2. The discharge characteristics of the example remain at almost the same level as the comparative example 2, and in this case, it can be confirmed that the performance for, for example, ISS vehicle use can be sufficiently satisfied. It can be confirmed that the cycle characteristics of the example are significantly improved as compared with the comparative examples 1 and 2. As described above, it can be confirmed that excellent charge acceptability, discharge characteristics, and cycle characteristics are compatible in the examples.

According to the present invention, it is possible to provide a phenolic resin having excellent cycle characteristics in a lead storage battery and a method for producing the same. Moreover, according to this invention, the resin composition containing the said phenolic resin can be provided. Furthermore, according to the present invention, it is possible to provide an electrode containing the phenolic resin and a method for manufacturing the same. The present invention can provide a lead storage battery including the electrode and a method for manufacturing the same.

DESCRIPTION OF SYMBOLS 1... Lead storage battery, 2... Battery case, 3... Lid, 4... Positive electrode terminal, 5... Negative electrode terminal, 6... Liquid stopper, 11... Electrode plate group, 12... Positive electrode plate, 13... Negative electrode plate, 14... Separator, 15... Positive side straps, 16... Negative side straps, 17... Inter-cell connecting parts, 18... Polar columns, 22, 32... Current collecting parts.

Claims (6)

And the electrode active material, a phenol resin, only including,
The phenolic resin is (a) at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives, (b) at least one selected from the group consisting of urea and urea derivatives, and (c) formaldehyde and formaldehyde. An electrode having a structural unit derived from the reaction of at least one selected from the group consisting of derivatives . The electrode according to claim 1, wherein the phenolic resin has a weight average molecular weight of 500 to 100,000. Lead acid battery provided with the electrode of Claim 1 or 2 . (A) at least one selected from the group consisting of phenolsulfonic acid and phenolsulfonic acid derivatives, (b) at least one selected from the group consisting of urea and urea derivatives, and (c) selected from the group consisting of formaldehyde and formaldehyde derivatives A method for producing an electrode, comprising a step of producing an electrode using a phenolic resin obtained by reacting at least one of The blending amount of the component (b) is 0.30 to 7.00 mol based on 1.00 mol of the component (a), and the blending amount of the component (c) is 1.00 mol of the component (a). The method for producing an electrode according to claim 4, wherein the amount is 1.50 to 10.50 mol in terms of formaldehyde. A method of manufacturing a lead storage battery, comprising a step of obtaining an electrode by the method of manufacturing an electrode according to claim 4 .

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