JPWO2015146919A1 - Lead acid battery - Google Patents

Abstract

The present invention provides a lead-acid battery capable of suppressing the stratification of the electrolyte and suppressing the deterioration of the high rate discharge performance. A lead-acid battery according to the present invention comprises a positive electrode plate (7) containing lead dioxide, a negative electrode plate (5) containing metal lead, and a separator (6) disposed between the positive electrode plate (7) and the negative electrode plate (5). ), A dilute sulfuric acid, and an electrolytic solution in which an electrode plate group including the positive electrode plate (7), the negative electrode plate (5), and the separator (6) is immersed, and a battery case for storing the electrode plate group and the electrolyte solution And an organic nonwoven fabric or porous membrane (8) provided around the negative electrode plate (5). A hydrophilic film (9) is formed on the surface of the organic nonwoven fabric or porous film (8). The hydrophilic film (9) is made of Al2O3 or a hydrophilic material (10) made of Al2O3 and SiO2, and an inorganic material or an organic material. It is comprised from the support body material (11) which consists of polymeric materials.

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are widely used for industrial purposes, and are used, for example, for automobile batteries, backup power supplies, and main power supplies for electric vehicles. In recent automobiles, an idling stop-and-start system (hereinafter referred to as “ISS”) that stops the engine during power generation control or when waiting for a signal has been adopted for the purpose of reducing CO2 emissions and reducing fuel consumption. It came to be. Since power generation by the alternator is not performed during idling stop, all electric power to the electric equipment is supplied from the lead storage battery, and the lead storage battery is charged deeper than before. Further, during running, the power generation of the alternator is controlled, so that the charging is insufficient.

  For this reason, in lead storage batteries, deep discharge and insufficient charge are repeated, and stratification of the electrolyte (a phenomenon in which the specific gravity of the electrolyte varies in the upper and lower portions of the battery due to repeated charge and discharge) is a short life of the lead storage battery. It has become apparent as a factor in the transformation. In the positive electrode of a lead-acid battery, water generated during discharge stirs the electrolyte solution, so the effect of stratification is small. However, in the negative electrode, since there is no such effect, stratification is likely to occur.

  In addition to extending the life of the ISS lead-acid battery by suppressing the stratification of the electrolyte, it is also necessary to improve battery performance such as high-rate discharge performance, internal resistance, and charge acceptance, which are engine startability. It is. In particular, extending the life and improving battery performance are indispensable for improving the performance of lead storage batteries for ISS used in harsh environments.

  Patent Document 1 discloses a sealed type in which an inorganic powder such as silica, titania, or alumina is contained in a bag-like separator made of a nonwoven fabric sheet mainly composed of fine glass, and at least one of a positive electrode and a negative electrode is accommodated in this separator. A lead acid battery is disclosed.

  Patent Document 2 discloses a lead storage battery in which a negative electrode is accommodated by a microporous polyethylene bag-shaped separator and an electrolytic solution containing Al ions and Li ions is used.

JP 2009-245901 A JP2012-077942A

  Patent Document 1 discloses a sealed lead-acid battery separator that has good electrolyte compatibility, mechanical strength, and short-circuit resistance, and also discloses that stratification of the electrolyte can be suppressed. Patent Document 2 discloses a lead acid battery that is excellent in low-temperature high-rate performance and has little lead sulfate accumulation associated with charge control and idling stop. However, the conventional techniques including the techniques described in Patent Documents 1 and 2 have not established a method for achieving both suppression of stratification of the electrolytic solution and suppression of deterioration of the high rate discharge performance.

  An object of this invention is to provide the lead acid battery which can suppress stratification of electrolyte solution and suppression of the fall of high rate discharge performance.

The lead acid battery according to the present invention has the following characteristics. A positive electrode plate containing lead dioxide, a negative electrode plate containing metallic lead, a separator disposed between the positive electrode plate and the negative electrode plate, and dilute sulfuric acid. From the positive electrode plate, the negative electrode plate, and the separator An electrolyte solution in which the electrode plate group is immersed, a battery case for storing the electrode plate group and the electrolyte solution, and an organic nonwoven fabric or a porous film provided around the negative electrode plate. A hydrophilic film is formed on the surface of the organic nonwoven fabric or porous film, and the hydrophilic film is made of Al ₂ O ₃ or a hydrophilic material made of Al ₂ O ₃ and SiO ₂ , an inorganic material, or an organic polymer material. It is comprised from the support body material which consists of.

  The lead storage battery by this invention can implement | achieve suppression of stratification of electrolyte solution, and suppression of the fall of high rate discharge performance.

It is a figure which shows the structure of the lead acid battery by the Example of this invention. 1 is a schematic cross-sectional view of an electrode plate group of a lead storage battery according to an embodiment of the present invention. It is the structure schematic of the electrode plate of the lead acid battery by the Example of this invention. It is a figure which shows the partial structure of the electrode group of the lead acid battery by the Example of this invention, especially the structure around a negative electrode plate.

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

(1) Stratification of electrolyte solution Stratification of the electrolyte solution is a phenomenon in which sulfate ions and hydrogen sulfate ions in the electrolyte solution are settled and a difference in the specific gravity of the electrolyte solution occurs above and below the battery case. Hereinafter, sulfate ions (SO ₄ ²⁻ ) and hydrogen sulfate ions (HSO ₄ ⁻ ) are collectively referred to as “sulfate ions”. By providing an organic nonwoven fabric or a porous membrane around the negative electrode plate and providing a physical barrier that inhibits the precipitation of sulfate ions, stratification of the electrolyte can be greatly suppressed. The organic non-woven fabric or porous film provided around the negative electrode plate can prevent the sulfate ions from being settled and can keep the concentration of sulfate ions inside the battery case uniform.

(2) High rate discharge performance The high rate discharge performance was better when the hydrophilic film was provided on the organic nonwoven fabric or porous film described in (1) than when the hydrophilic film was not provided. This is thought to be due to a chemical interaction between sulfate ions and the hydrophilic membrane. _On the surface of SiO ₂ or Al ₂ O ₃ used for the hydrophilic film, —OH groups are generated. The —OH group on the surface of the hydrophilic membrane exists in the form of —OH ²⁺ as a result of protonation in an aqueous sulfuric acid solution that is an electrolytic solution. It is considered that sulfate ions (SO ₄ ²⁻ and HSO ₄ ⁻ ) are attracted to this —OH ²⁺ to cause a chemical interaction. That is, it is considered that the hydrophilic membrane provided on the organic nonwoven fabric or the porous membrane generates an interaction with sulfate ions, adsorbs and collects sulfate ions, and supplies them to the electrode. For this reason, it is considered that the supply efficiency of sulfate ions from the hydrophilic film to the electrode determines the high rate discharge performance. Therefore, the material of the hydrophilic film was examined based on the following two points.

  The first point is the number of interaction points generated on the surface of the hydrophilic film and causing interaction with sulfate ions. In the present invention, the material of the hydrophilic film was examined in consideration of the number of —OH groups serving as interaction points with sulfate ions as the number of interaction points. The second point is the strength of the interaction (adsorption energy, etc.) acting between sulfate ions and the hydrophilic film. Hereinafter, a case where adsorption energy is taken as an example of an interaction index will be described. If the adsorption energy is too weak, the chemical interaction between sulfate ions and the hydrophilic film is weakened, the number of sulfate ions adsorbed on the hydrophilic film is reduced, and the supply efficiency of sulfate ions to the electrode is reduced. On the other hand, if the adsorption energy is too strong, the sulfate ions remain adsorbed on the hydrophilic film, and the supply efficiency of sulfate ions to the electrode also decreases. That is, it is preferable that the adsorption energy acting between the sulfate ion and the hydrophilic film is an appropriate value.

  In the lead storage battery according to the present invention, an organic nonwoven fabric or a porous film is provided around the negative electrode plate, and a hydrophilic film is formed on the organic nonwoven fabric or the porous film.

The hydrophilic film is composed of a hydrophilic material and a support material, and a hydrophilic coating obtained by diluting a mixed solution of the hydrophilic material and the support material with a water-soluble solvent (for example, an alcohol solvent or water) It is formed by applying to the surface of a nonwoven fabric or porous membrane. In consideration of the adsorption energy acting between the sulfate ion and the hydrophilic film, the hydrophilic material includes at least one of Al ₂ O ₃ , a mixture of Al ₂ O ₃ and SiO ₂ , BaSO ₄ , and TiO _2. It is preferable to use it. In particular, it is preferable to use Al ₂ O ₃ or a mixture of Al ₂ O ₃ and SiO ₂ as the hydrophilic material. When Al ₂ O ₃ is used, a hydrophilic alumina sol can be used as the hydrophilic material. When a mixture of Al ₂ O ₃ and SiO ₂ is used, a mixture of alumina sol and colloidal silica is used as the hydrophilic material. Can be used. As the support material, an inorganic material or an organic polymer material can be used. For example, silica sol, acrylamide, or alkoxysilane can be used.

  The thickness of the organic nonwoven fabric or porous membrane is preferably 0.03 mm to 0.1 mm in consideration of the ability to prevent the precipitation of sulfate ions, the influence on the battery reaction, the strength, and the like. Depending on the fibers, when a porous membrane is used, it can be determined according to the pore diameter and material of the porous membrane. Since the organic nonwoven fabric has the advantage that it is easier to manufacture than the inorganic nonwoven fabric, the organic nonwoven fabric is adopted as the nonwoven fabric in the lead storage battery according to the present invention. The porous film has pores of 100 nm to 1 μm, and the pore structure may be a regular structure or an irregular structure such as an organic nonwoven fabric.

  The hydrophilic film is preferably formed on the surface of the organic nonwoven fabric or porous film with a thickness of 10 nm to 1000 nm. If it is thinner than 10 nm, the effect of adsorbing and holding sulfate ions is reduced, and if it is thicker than 1000 nm, the internal resistance of the battery is increased.

  By providing an organic non-woven fabric or porous film with a hydrophilic film formed around the negative electrode plate, it is possible to suppress stratification of the electrolyte solution and decrease in high-rate discharge performance in the lead-acid battery. In particular, in the lead-acid battery according to the present invention, when an organic nonwoven fabric or porous membrane having a hydrophilic film formed thereon is provided around the negative electrode plate separately from the separator, the organic nonwoven fabric or porous membrane is disposed in a state of closer contact with the negative electrode plate. Therefore, the effect of suppressing stratification is higher than when the separator is provided with an effect of suppressing stratification.

FIG. 1A is a diagram showing a configuration of a lead storage battery according to an embodiment of the present invention, FIG. 1B is a schematic cross-sectional view of an electrode plate group of the lead storage battery according to this embodiment, and FIG. 1C is a lead according to this embodiment. It is a structure schematic diagram of the electrode plate of a storage battery. The lead acid battery according to this embodiment includes a battery case 1 and a terminal 2 as an exterior part. Inside the battery case 1, a pole column 3 and a plate group 4 are provided. The pole 3 connects the electrode plate group 4 and the terminal 2. The electrode plate group 4 is disposed between a negative electrode plate 5 containing metal lead (Pb) as an active material, a positive electrode plate 7 containing lead dioxide (PbO ₂ ) as an active material, and the negative electrode plate 5 and the positive electrode plate 7. The separator 6 is provided. The negative electrode plate 5 and the positive electrode plate 7 are plate-like, and the negative electrode plate 5 and the positive electrode plate 7 are alternately stacked via the separator 6 to constitute an electrode plate group (electrode group) 4. The electrode plate group 4 is immersed in an electrolytic solution made of dilute sulfuric acid and accommodated in the battery case 1 to constitute a lead storage battery.

  FIG. 2 is a diagram showing a partial structure of the electrode plate group 4 of the lead-acid battery according to the embodiment of the present invention, particularly the structure around the negative electrode plate 5. An organic nonwoven fabric or porous film 8 is provided around the negative electrode plate 5. The separator 6 may be plate-shaped or bag-shaped, and is disposed between the organic nonwoven fabric or porous film 8 provided around the negative electrode plate 5 and the positive electrode plate 7. When the separator 6 is bag-shaped, the separator 6 houses the negative electrode plate 5 and the organic nonwoven fabric or porous membrane 8. A hydrophilic film 9 is formed on the surface of the organic nonwoven fabric or porous film 8. The hydrophilic film 9 includes a hydrophilic material 10 and a holder material 11.

  The organic nonwoven fabric or porous membrane 8 is provided so as to face at least the surface of the negative electrode plate 5 facing the separator 6 and the surface of the negative electrode plate 5 opposite to this surface. Furthermore, the organic nonwoven fabric or the porous film 8 may be provided so as to face a surface other than these surfaces among the side surfaces of the negative electrode plate 5, or may be provided so as to face the bottom surface of the negative electrode plate 5. For example, the organic nonwoven fabric or the porous film 8 can be provided around the negative electrode plate 5 by being wound around the negative electrode plate 5.

  In the example shown in FIG. 2, the organic nonwoven fabric or porous film 8 faces the bottom surface and two side surfaces (a surface facing the separator 6 and a surface opposite to this surface) of the negative electrode plate 5. 5 is provided.

  The organic nonwoven fabric or the porous membrane 8 may be a bag and may accommodate the negative electrode plate 5. The hydrophilic film 9 may be formed on the surface of the separator 6 in addition to the organic nonwoven fabric or the porous film 8. Further, the hydrophilic film 9 may be formed on the surface of the separator 6 without providing the organic nonwoven fabric or the porous film 8 around the negative electrode plate 5.

  Hereinafter, the lead acid battery according to the present embodiment will be described.

[1] Organic nonwoven fabric or porous membrane Examples of materials used for the organic nonwoven fabric or porous membrane on which a hydrophilic membrane is formed include polypropylene, cellulose, polyethylene, nylon, aramid, and polyester. A hydrophilic film described below can be applied to an organic nonwoven fabric or porous membrane, and heated and thermally cured to form a hydrophilic membrane on the surface of the organic nonwoven fabric or porous membrane.

[2] Hydrophilic paint The hydrophilic paint for forming the hydrophilic film is composed of (a) a hydrophilic material, (b) a support material, and (c) a solvent. In both the hydrophilic material and the support material, solid components are present in the dispersion medium at a constant concentration. The weight ratio of the solid component of the hydrophilic material and the solid component of the holding material is preferably 90:10 to 70:30. When the weight ratio of the solid component is within this range, it is suitable for preparing a hydrophilic paint by mixing the hydrophilic material and the support material. After mixing the dispersion containing the hydrophilic material and the dispersion containing the holding material, the total concentration of the solid components of the hydrophilic material and the holding material is 0.5 wt% to 5 wt% with respect to the dilution solvent. The mixture is diluted with a solvent so that If the concentration of the solid component is less than 0.5 wt%, the thickness of the hydrophilic film becomes non-uniform, and if it is more than 5 wt%, it is difficult to form the hydrophilic film, which is not preferable.

(A) Hydrophilic material An inorganic material that does not dissolve even when immersed in an acidic aqueous solution is preferable as a hydrophilic material because it can maintain hydrophilicity for a long period of time. Examples of such inorganic materials include hydrophilic silica particles and hydrophilic alumina sol. Specifically, colloidal silica IPA-ST-UP, IPA-ST, ST-OXS, ST-K2, and LSS-35 manufactured by Nissan Chemical Industries, Ltd., and alumina sol AS-200 manufactured by Nissan Chemical Industries, Ltd. Is mentioned. Since colloidal silica uses alcohol as a dispersion medium and alumina sol uses water as a dispersion medium, they can be easily mixed together.

Colloidal silica has a specific surface area preferably used particles is 130m ² / g~1000m ² / g approximately. Assuming that the shape of the colloidal silica is spherical, the particle diameter of the colloidal silica having a specific surface area within this range is 2 nm to 20 nm. Alumina sol, preferably the specific surface area of the contained alumina particles to use those which are 200m ² / g~400m ² / g approximately. Assuming that the shape of the alumina particles is plate-like, for example, an alumina sol containing alumina particles whose dimensions (length, width, and height) are 10 nm × 10 nm × 100 nm can be used.

Table 1 is a table showing a calculation example of the number of interaction points (-OH groups) generated on the surface of the hydrophilic film and causing interaction with sulfate ions when colloidal silica and alumina sol are used as the hydrophilic material. It is. In Table 1, (1) is a case where hydrophilic silica particles (SiO ₂ ) are used as the hydrophilic material, and the weight ratio of the solid component of the hydrophilic material to the support material is 80:20. (2) is the case where hydrophilic silica particles (SiO ₂ ) are used as the hydrophilic material and the weight ratio of the solid component of the hydrophilic material and the support material is 80:20. However, the specific surface area of the silica particles is about 7.7 times that of the silica particles of (1). (3) is a case where alumina sol (Al ₂ O ₃ ) is used as the hydrophilic material and the weight ratio of the solid component of the hydrophilic material to the support material is 90:10.

Table 1 shows, for each of (1) to (3), the shape, particle size (nm), specific surface area (m ² / g), number of interaction points per particle of hydrophilic material (pieces / piece) Particles), the number of interaction points per gram of hydrophilic material (number / g), and the number of interaction points per gram of hydrophilic film (number / g). However, in (1) and (2), the size of the particle is assumed to be a spherical shape, and in (3) the particle size is assumed to be a plate shape in (3) (vertical, horizontal, And height).

In calculating the number of interaction points with sulfate ions in each hydrophilic material, the following calculation formula was used.
(E) = (A) × (D)
= (A) × {(B) / (C)}
However,
(A) is the number of interaction points of sulfate ions per particle of hydrophilic material,
(B) is the volume of hydrophilic material per gram of hydrophilic material or hydrophilic film,
(C) is the volume per particle of the hydrophilic material,
(D) is the number of particles of hydrophilic material or hydrophilic material contained per gram of hydrophilic material,
(E) is the number of interaction points of sulfate ions per gram of hydrophilic material or hydrophilic membrane,
It is.

According to Table 1, the number of interaction points is 4-6 in the case of (3) using Al ₂ O ₃ as the hydrophilic material than in the cases of (1) and (2) using SiO _2. An order of magnitude larger. From this, it can be seen that the use of Al ₂ O ₃ as the hydrophilic material can greatly increase the number of interaction points with sulfate ions.

In addition to using Al ₂ O ₃ alone as a hydrophilic material, it is also possible to use a mixture of Al ₂ O ₃ and SiO ₂ . When this mixture is used, the number of interaction points with sulfate ions is increased by Al ₂ O ₃ , and an appropriate interaction between sulfate ions and a hydrophilic film can be realized by SiO ₂ . When a mixture of Al ₂ O ₃ and SiO ₂ is used as the hydrophilic material, 10 wt% or more of Al ₂ O ₃ is included in the hydrophilic material. When Al ₂ O ₃ is less than 10 wt%, the number of interaction points with sulfate ions cannot be effectively increased.

The number of interaction points with sulfate ions is 1 × 10 ²¹ to 1 × 10 ²⁴ per g for Al ₂ O _{3 and} 1 × 10 ¹⁷ to 1 × 10 ²⁰ per g for SiO _2. It is possible to obtain excellent high rate discharge performance by forming a hydrophilic film. Therefore, when the hydrophilic material is made of Al ₂ O ₃ , the number of interaction points is preferably 1 × 10 ²¹ to 1 × 10 ²⁴ per gram of Al ₂ O ₃ , and the hydrophilic material is Al ₂ When composed of O ₃ and SiO ₂ , the number of interaction points is 1 × 10 ²¹ to 1 × 10 ²⁴ per g of Al ₂ O ₃ , and 1 × 10 ¹⁷ per g of SiO _2. It is preferably ˜1 × 10 ²⁰ pieces.

For towards the number of interaction points _Al 2 _{O 3} is larger than SiO _2, when using the mixture of _Al 2 _{O 3} and SiO ₂ as the hydrophilic material, the interaction point in an amount of _Al 2 _{O 3} The number of is considered to be determined. For this reason, even when Al ₂ O ₃ is used as a hydrophilic material for forming the hydrophilic film or when a mixture of Al ₂ O ₃ and SiO ₂ is used, the number of interaction points is 1 × per 1 g of the hydrophilic film. If it is 10 ²¹ pieces-1x10 ²⁴ pieces, since the fall of high rate discharge performance can be suppressed especially, it is preferable.

(B) Holder material An organic polymer material or an inorganic material can be used for the holder material. Examples of the organic polymer material used for the holding material include a polymer obtained by heating polyethylene glycol, polyvinyl alcohol, or the like. Examples of the inorganic material used for the holder material include a material that becomes a holder by heating, such as silica sol. Among them, acrylamide and silica sol are excellent in long-term stability in an acidic aqueous solution. Specific examples of the silica sol include Colcoat PX manufactured by Colcoat.

(C) Solvent The solvent used for diluting the liquid mixture of the hydrophilic material and the support material is preferably a solvent that has good dispersibility and compatibility with the hydrophilic material and the support material, and is likely to volatilize during thermosetting. . As a solvent satisfying these conditions, an alcohol solvent or water is preferable. Furthermore, when the heat resistance of the organic nonwoven fabric or the porous membrane is taken into consideration, the boiling point is more preferably 100 ° C. or lower. Specific examples of the solvent include water, methanol, ethanol, and isopropyl alcohol.

Table 2 is a table showing the configuration of the lead storage battery according to the example of the present invention, the evaluation of the effect of suppressing the stratification of the electrolytic solution, and the evaluation of the high rate discharge performance. The structure of the lead-acid battery includes the material and thickness of the organic nonwoven fabric (mm), the thickness of the hydrophilic film (nm), the number of interaction points per 1 g of the hydrophilic film (pieces / g), and the hydrophilic material of the hydrophilic film. The body material and the weight ratio of these solid components are shown. The material of the organic nonwoven fabric was represented by “PP” for polypropylene and “PE” for polyethylene. When the mixture of alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) is used as the hydrophilic material, the number of interaction points per 1 g of hydrophilic film is the total number of interaction points of alumina sol and colloidal silica. Show. Table 2 also shows a lead storage battery manufactured as a comparative example. Hereinafter, each example and each comparative example will be described. In the following examples and comparative examples, an organic nonwoven fabric was provided around the negative electrode plate 5.

  As shown in FIG. 2, the lead storage battery according to Example 1 is provided with an organic nonwoven fabric 8 on which a hydrophilic film 9 is formed around the negative electrode plate 5. A hydrophilic film 9 was formed on the surface of the organic nonwoven fabric 8 as follows.

  The organic nonwoven fabric 8 made of polypropylene and having a thickness of 0.1 mm was used.

Alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) were used as the hydrophilic material 10, and silica sol was used as the support material 11. Specifically, the alumina sol AS-200 manufactured by Nissan Chemical Industries, Ltd. was used as the alumina sol, the colloidal silica IPA-ST-UP manufactured by Nissan Chemical Industries, Ltd. was used as the colloidal silica, and the Colcoat PX manufactured by Colcoat was used as the silica sol. . In the hydrophilic material 10, the weight ratio of alumina sol to colloidal silica was 80:20. That is, the hydrophilic material 10 contains 80 wt% alumina sol (Al ₂ O ₃ ).

  The hydrophilic material 10 and the support material 11 were mixed so that the weight ratio (X: Y) of the solid component of the hydrophilic material 10 (X) and the support material 11 (Y) was 80:20. A hydrophilic paint was prepared by diluting this mixed solution with ethanol so that the concentration of the solid component was 5 wt%.

After the organic nonwoven fabric 8 was immersed in this hydrophilic paint, the organic nonwoven fabric 8 was pulled up at a speed of 156 mm / min. The organic nonwoven fabric 8 is sandwiched between paper wipers and the roller is rolled from above to remove excess hydrophilic paint adhering to the organic nonwoven fabric 8, and then the organic nonwoven fabric 8 is placed in a constant temperature bath heated to 60 ° C. for 1 hour. The solvent was removed. In this way, a hydrophilic film 9 was formed on the surface of the organic nonwoven fabric 8. The hydrophilic film 9 has a thickness of 50 nm, and the number of interaction points per 1 g is 1.0 × 10 ²³ .

  An organic nonwoven fabric 8 on which a hydrophilic film 9 was formed was placed around the negative electrode plate 5, and a dilute sulfuric acid was used as an electrolytic solution to produce a lead storage battery as shown in FIG.

This lead storage battery was subjected to a cycle test, and first, the effect of suppressing the stratification of the electrolyte was evaluated. In the cycle test, the lead-acid battery is placed in an atmosphere of 25 ° C.
(I) Discharge at a discharge current of 45 A for 59 seconds,
(Ii) Discharge at a discharge current of 300 A for 1 second,
(Iii) constant current and constant voltage charging at a charging voltage of 14.0 V (limit current of 100 A) for 60 seconds;
(I), (ii), and (iii) are taken as one cycle, and this cycle is repeated 3600 times (from Battery Industry Association Standard SBA S0101). The difference in specific gravity of the electrolyte solution between the upper part and the lower part in the battery case in the initial cycle (3600th) in which the stratification of the electrolyte solution is noticeable was used as an index for stratification. That is, in the 3600th cycle, the specific gravity of the electrolyte in the lower part of the battery case and the specific gravity of the electrolyte in the upper part are measured, and the difference between these specific gravities is obtained. The effect was evaluated. The upper part in the battery case is a position 1 cm above the upper end of the electrode plate group 4, and the lower part in the battery case is a position 1 cm above the lower end of the electrode plate group 4. Specific evaluation criteria are “A” when the specific gravity difference is 0.02 or less, “B” when 0.02 or more and 0.04 or less, and “B” or more than 0.04 and 0.07 or less. The case where “C” was greater than 0.07 was designated “D”. In this evaluation standard, stratification is suppressed in the order of A, B, C, and D.

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed.

  Next, the high rate discharge performance of the lead storage battery was evaluated. The high rate discharge performance was measured in accordance with the JIS standard with a discharge current of 150 A and a final voltage of 6 V after the lead storage battery was allowed to stand for 16 hours under a temperature condition of −15 ° C. In general, it is known that when an organic nonwoven fabric or a porous membrane 8 is installed inside a lead-acid battery, high-rate discharge performance is degraded. Therefore, when the high-rate discharge performance when the organic nonwoven fabric or the porous membrane 8 is not installed around the negative electrode plate 5 is 100, the decrease rate of the high-rate discharge performance is small (when the high-rate discharge performance is close to 100). It was evaluated as a case where a decrease in high rate discharge performance could be suppressed. Specific evaluation criteria were high rate discharge performance of 100 or less and 95 or more as “A”, less than 95 or 91 or more as “B”, less than 91 or 87 or more as “C”, and less than 87 as “D”. In this evaluation standard, a decrease in the high rate discharge performance is suppressed in the order of A, B, C, and D.

  The lead storage battery according to the present example has an evaluation A of high-rate discharge performance of 95, and it has been found that the decrease rate of the high-rate discharge performance is extremely small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 2 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, only the alumina sol (Al ₂ O ₃ ) was used as the hydrophilic material 10 and no colloidal silica (SiO ₂ ) was used. That is, the hydrophilic material 10 contains 100 wt% alumina sol (Al ₂ O ₃ ). The weight ratio (X: Y) of the solid component of the hydrophilic material 10 (X) and the holding material 11 (Y) is 90:10. The number of interaction points per 1 g of the hydrophilic film 9 is 1.3 × 10 ²³ .

  The lead acid battery according to this example has a small specific gravity difference of 0.04, which is evaluated as B, indicating that stratification is suppressed. In addition, the lead storage battery according to this example has a high-rate discharge performance of 93 and an evaluation B, which indicates that the reduction rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 3 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) were used as the hydrophilic material 10, and the weight ratio of alumina sol to colloidal silica was 70:30. That is, the hydrophilic material 10 includes 70 wt% alumina sol (Al ₂ O ₃ ). The number of interaction points per 1 g of the hydrophilic film 9 is 9.1 × 10 ²² .

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed. In addition, the lead storage battery according to this example had a high rate discharge performance of 96, which was evaluated as A, and it was found that the decrease rate of the high rate discharge performance was small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 4 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, the organic nonwoven fabric 8 was made of polyethylene.
The thickness of the hydrophilic film 9 is 10 nm.

  The lead acid battery according to this example has a small specific gravity difference of 0.04, which is evaluated as B, indicating that stratification is suppressed. In addition, the lead storage battery according to this example has a high-rate discharge performance of 94, which is evaluated as B, and it has been found that the decrease rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 5 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, only the alumina sol (Al ₂ O ₃ ) was used as the hydrophilic material 10 and no colloidal silica (SiO ₂ ) was used. That is, the hydrophilic material 10 contains 100 wt% alumina sol (Al ₂ O ₃ ). Acrylamide was used as the holder material 11. The hydrophilic film 9 has a thickness of 100 nm and the number of interaction points per 1 g is 1.3 × 10 ²³ .

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed. In addition, the lead storage battery according to the present example has a high rate discharge performance of 92 and an evaluation B, and it was found that the decrease rate of the high rate discharge performance was small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 6 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

  In the lead storage battery according to this example, acrylamide was used as the support material 11. The thickness of the hydrophilic film 9 is 60 nm.

  The lead acid battery according to this example has a small specific gravity difference of 0.04, which is evaluated as B, indicating that stratification is suppressed. In addition, the lead storage battery according to this example has a high-rate discharge performance of 94, which is evaluated as B, and it has been found that the decrease rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 7 has the same configuration as the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, the organic nonwoven fabric 8 made of polyethylene and having a thickness of 0.05 mm was used. As the hydrophilic material 10, alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) were used, and the weight ratio of the alumina sol and colloidal silica was 70:30. That is, the hydrophilic material 10 includes 70 wt% alumina sol (Al ₂ O ₃ ). Acrylamide was used as the support material 1. The number of interaction points per 1 g of the hydrophilic film 9 is 9.1 × 10 ²² .

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed. In addition, the lead storage battery according to this example has an evaluation A of high-rate discharge performance of 95, and it has been found that the decrease rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead-acid battery according to Example 8 has the same configuration as the lead-acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, the organic nonwoven fabric 8 having a thickness of 0.03 mm was used. Alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) were used as the hydrophilic material 10, and the weight ratio of alumina sol to colloidal silica was 10:90. That is, the hydrophilic material 10 contains 10 wt% alumina sol (Al ₂ O ₃ ). The weight ratio (X: Y) of the solid component of the hydrophilic material 10 (X) and the holding material 11 (Y) is 90:10. The number of interaction points per 1 g of the hydrophilic film 9 is 1.2 × 10 ²² .

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed. In addition, the lead storage battery according to this example has a high-rate discharge performance of 94, which is evaluated as B, and it has been found that the decrease rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

  The lead acid battery according to Example 9 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

In the lead storage battery according to this example, alumina sol (Al ₂ O ₃ ) and colloidal silica (SiO ₂ ) were used as the hydrophilic material 10, and the weight ratio of alumina sol to colloidal silica was 20:80. That is, the hydrophilic material 10 contains 20 wt% alumina sol (Al ₂ O ₃ ). The weight ratio (X: Y) of the solid component of the hydrophilic material 10 (X) and the holding material 11 (Y) is 70:30. The hydrophilic film 9 has a thickness of 60 nm, and the number of interaction points per gram is 2.2 × 10 ²² .

  The lead acid battery according to this example had a small specific gravity difference of 0.03 as the electrolytic solution, and was evaluated as B, indicating that stratification was suppressed. In addition, the lead storage battery according to this example has a high-rate discharge performance of 94, which is evaluated as B, and it has been found that the decrease rate of the high-rate discharge performance is small. That is, it was found that the lead storage battery according to the present example can suppress a decrease in high rate discharge performance.

[Comparative Example 1]
The lead acid battery according to Comparative Example 1 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

  In the lead storage battery according to this comparative example, the organic nonwoven fabric or the porous film 8 was not provided around the negative electrode plate 5.

  The lead acid battery according to this comparative example has an extremely large specific gravity difference of 0.08, which is evaluated as D, and it was found that stratification cannot be suppressed. Moreover, since the lead acid battery by this comparative example does not provide the organic nonwoven fabric or the porous film 8 around the negative electrode plate 5, high-rate discharge performance is 100 of an evaluation reference value.

  By providing the organic nonwoven fabric or the porous membrane 8 around the negative electrode plate 5 according to this comparative example and Examples 1 to 9, the specific gravity difference of the electrolytic solution can be reduced, and the stratification of the electrolytic solution can be suppressed. It could be confirmed.

[Comparative Example 2]
The lead acid battery according to Comparative Example 2 has the same configuration as that of the lead acid battery according to Example 1, except for the following points. Only the differences will be described below.

  In the lead storage battery according to this comparative example, the organic nonwoven fabric 8 made of polypropylene and having a thickness of 0.1 mm is provided around the negative electrode plate 5, but the hydrophilic film 9 is not formed on the organic nonwoven fabric 8.

  The lead acid battery according to this comparative example was evaluated B when the specific gravity difference of the electrolyte was 0.04, and the high-rate discharge performance was rated B at 92.

  The lead acid batteries of Examples 1 to 9 have the largest difference in specific gravity of the electrolytes in the lead acid batteries of Examples 2, 4, and 6. Even in the lead acid batteries of these Examples, the difference in specific gravity of the electrolyte is 0.04. It is. However, in the lead storage batteries of these examples, the high rate discharge performances are 93, 94, and 94, respectively, and the reduction rate of the high rate discharge performance is smaller than that of the lead storage battery according to this comparative example. That is, the lead acid battery according to this comparative example has the same specific gravity difference in the electrolyte solution as the lead acid batteries of Examples 2, 4, and 6, but the reduction rate of the high rate discharge performance is large.

  Moreover, the lead-acid battery of Example 5 has the smallest high-rate discharge performance among the lead-acid batteries of Examples 1 to 9 (the reduction rate of the high-rate discharge performance is large), and the lead-acid battery of Example 5 also has a high rate. The discharge performance is 92. However, in the lead storage battery of Example 5, the specific gravity difference of the electrolytic solution is as small as 0.03. That is, the lead storage battery according to this comparative example has the same degree of decrease in the high rate discharge performance as compared with the lead storage battery of Example 5, but the specific gravity difference of the electrolyte is large.

  From the above results, it was found that the lead storage battery according to this comparative example cannot achieve both suppression of stratification and suppression of deterioration of high-rate discharge performance. Furthermore, by this comparative example and Examples 1-9, it has confirmed that the fall of high rate discharge performance could be suppressed by forming the hydrophilic film 9 in the organic nonwoven fabric 8. FIG.

  In addition, this invention is not limited to said Example, Various modifications are included. For example, the above-described embodiments are described in detail for easy understanding of the present invention, and the present invention is not necessarily limited to an aspect including all the configurations described.

  DESCRIPTION OF SYMBOLS 1 ... Battery case, 2 ... Terminal, 3 ... Polar pole, 4 ... Electrode plate group, 5 ... Negative electrode plate, 6 ... Separator, 7 ... Positive electrode plate, 8 ... Organic nonwoven fabric or porous membrane, 9 ... Hydrophilic membrane, 10 ... Hydrophilic material, 11 ... holder material.

Claims (10)

A positive electrode plate containing lead dioxide;
A negative electrode plate containing metallic lead;
A separator disposed between the positive electrode plate and the negative electrode plate;
An electrolytic solution made of dilute sulfuric acid, in which an electrode plate group consisting of the positive electrode plate, the negative electrode plate, and the separator is immersed;
A battery case for storing the electrode plate group and the electrolytic solution;
An organic nonwoven fabric or a porous film provided around the negative electrode plate,
A hydrophilic film is formed on the surface of the organic nonwoven fabric or porous film,
The hydrophilic film, lead-acid batteries, characterized in that it is composed of a hydrophilic material consisting of from consisting or Al ₂ O ₃ and SiO ₂ Metropolitan Al ₂ O _3, and support material made of an inorganic material or an organic polymer material . The lead acid battery according to claim 1, wherein the hydrophilic film includes 10 wt% or more of Al ₂ O ₃ in the hydrophilic material. 3. The lead acid battery according to claim 2, wherein the number of —OH groups generated on the surface of the hydrophilic material is 1 × 10 ²¹ to 1 × 10 ²⁴ per 1 g of the hydrophilic film. The hydrophilic membrane, when said hydrophilic material is made of _Al 2 _{O 3} is _Al 2 _O The number of -OH groups that are generated on the surface of _3, Al 2 _{O 3} of 1 × ^{10 21} cells to 1 per 1g The lead acid battery according to claim 2, wherein the number is × 10 ²⁴ . The hydrophilic membrane, when said hydrophilic material consists of _Al 2 _{O 3} and SiO ₂ Metropolitan, _Al 2 number of -OH groups that are generated on the surface of the _{O 3 is,} Al 2 _O 1 g per 1 × 10 ₃ The number of —OH groups generated on the surface of SiO ₂ is ²¹ × 1 × 10 ²⁴ and 1 × 10 ¹⁷ to 1 × 10 ²⁰ per 1 g of SiO ₂ . Lead acid battery.   The lead acid battery according to claim 2, wherein the hydrophilic film has a solid component weight ratio of 90:10 to 70:30 of the hydrophilic material and the support material.   The lead acid battery according to claim 2, wherein the hydrophilic film has a thickness of 10 nm to 1000 nm.   The lead acid battery according to claim 2, wherein the organic nonwoven fabric or the porous membrane has a thickness of 0.03 mm to 0.1 mm.   The lead acid battery according to claim 2, wherein the hydrophilic film is formed on a surface of the separator. A positive electrode plate containing lead dioxide;
A negative electrode plate containing metallic lead;
A separator disposed between the positive electrode plate and the negative electrode plate;
An electrolytic solution made of dilute sulfuric acid, in which an electrode plate group consisting of the positive electrode plate, the negative electrode plate, and the separator is immersed;
A battery case for storing the electrode plate group and the electrolytic solution;
A hydrophilic film is formed on the surface of the separator,
The hydrophilic film, lead-acid batteries, characterized in that it is composed of a hydrophilic material consisting of from consisting or Al ₂ O ₃ and SiO ₂ Metropolitan Al ₂ O _3, and support material made of an inorganic material or an organic polymer material .

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