JP6908052B2 - Liquid lead-acid battery - Google Patents

Description

The present invention relates to a liquid lead-acid battery.

Lead-acid batteries are widely used in industry, for example, in automobile batteries, backup power supplies, and main power supplies for electric vehicles. In recent years, automobiles have adopted an idling stop and start system (hereinafter referred to as "ISS") that stops the engine when controlling power generation, waiting for a signal, etc., for the purpose of carbon dioxide emission regulation measures, fuel efficiency, etc. It has become so.

Since the alternator does not generate electricity during idling stop, all the power to the electric equipment is supplied from the lead-acid battery, and the lead-acid battery is charged deeper than before. In addition, since the alternator's power generation is controlled even during driving, the battery becomes insufficiently charged.

When deep discharge and insufficient charging are repeated in a lead-acid battery, stratification of the electrolytic solution occurs, which has become apparent as a factor of shortening the life of the lead-acid battery. Here, the stratification by repeated charge and discharge, sulfate ions in the electrolyte (SO 4 ^_2-) and hydrogen sulfate ion (HSO 4 _-) ^{(hereinafter,} these are collectively referred to as "sulfate ions") sedimentation Then, it refers to a phenomenon in which the specific gravity of the electrolytic solution differs between the upper and lower parts of the electric tank. In particular, lead-acid batteries for ISS vehicles are used in an intermediate charged state in which it is difficult to obtain the stirring effect of the electrolytic solution, so that suppression of stratification is an important issue.

In response to such a problem, Patent Document 1 describes a technique relating to a separator for a liquid lead-acid battery, which comprises laminating an acid-resistant microporous resin film sheet and an acid-resistant non-woven fabric sheet. There is. The acid-resistant non-woven fabric sheet is characterized in that wool-like glass fibers having a fiber diameter of 2 to 4.5 μm are composed of 50% by mass or more and have an average pore diameter of 20 to 100 μm.

Japanese Unexamined Patent Publication No. 2013-206571

However, since the acid-resistant non-woven fabric sheet described in Patent Document 1 has an average pore diameter of 20 to 100 μm, a large amount of sulfate ions are generated in the vicinity of the electrode plate during charging, especially when the battery size (width dimension) is large. May slip through the pores and settle, causing the electrolyte to stratify.

Therefore, an object of the present invention is to suppress stratification of an electrolytic solution and improve durability in a liquid lead-acid battery having a predetermined size.

According to the study by the present inventors, the water generated at the time of discharge promotes the mixing of the electrolytic solution in the vicinity of the positive electrode, so that the effect of stratification is small, but in the vicinity of the negative electrode, there is no such effect. Stratification is likely to occur. Further, stratification occurs more remarkably as the size of the lead storage battery becomes larger. Therefore, as a result of further studies, the present inventors have provided a film body having pores between the negative electrode and the separator in a liquid lead-acid battery having a predetermined width dimension, and the average pore diameter of the film body. It has been found that when the thickness is 15 μm or less and the porosity is 93% or less, it is possible to suppress the stratification of the electrolytic solution and improve the durability.

That is, in one embodiment, the present invention comprises a positive electrode plate, a negative electrode plate, a separator arranged between the positive electrode plate and the negative electrode plate, a film body arranged between the negative electrode plate and the separator, and an electrolytic solution. A liquid lead-acid battery having a positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank for accommodating an electrolytic solution, and having a width dimension of D or more in the category specified in JIS D5301. Is a liquid lead-acid battery having pores with an average pore diameter of 15 μm or less and a pore ratio of a film body of 93% or less.

In another aspect, the present invention comprises a positive electrode plate, a negative electrode plate, a separator arranged between the positive electrode plate and the negative electrode plate, a film body arranged between the negative electrode plate and the separator, and an electrolytic solution. A liquid lead having a positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank for accommodating an electrolytic solution, and having a width dimension of LBN0 to 6 or LN0 to 6 in the classification specified in EN 50342-2. A storage battery, which is a liquid lead-acid battery having an average pore diameter of 15 μm or less and a pore ratio of 93% or less.

In one aspect, the porosity of the membrane is 80% or more.

In one embodiment, the film body has the following thickness and ^30g / ^{m 2 ~50g} / m 2 basis weight 0.3 mm.

In one embodiment, the film body comprises a base material and a hydrophilic film formed on the base material, and the base material is at least one selected from an organic woven fabric, an organic non-woven fabric and a porous film, and is hydrophilic. The coating comprises at least one hydrophilic material selected from alumina and silica and at least one holding material selected from acrylamide, silica sol and silane coupling agents.

In one embodiment, the hydrophilic material comprises elemental alumina, elemental silica or a mixture of alumina and silica.

In one embodiment, the thickness of the hydrophilic coating is 10 nm to 1000 nm.

In one aspect, the membrane comprises an inorganic non-woven fabric.

In one embodiment, the surface of the separator on the negative electrode plate side contains at least one hydrophilic material selected from alumina and silica and at least one holding material selected from acrylamide, silica sol and a silane coupling agent. A hydrophilic film is formed.

According to the present invention, in a liquid lead-acid battery having a predetermined size, stratification of an electrolytic solution can be suppressed and durability can be improved.

It is a perspective view which shows the overall structure and the internal structure of the lead storage battery which concerns on one Embodiment. It is a perspective view which shows the electrode group of the lead storage battery which concerns on one Embodiment. It is a schematic cross-sectional view which shows the cross-sectional view taken along the line I-I in FIG. It is a top view which shows the negative electrode plate which concerns on one Embodiment. (A) is a plan view of a main part showing a part P of the negative electrode plate of FIG. 4, and (b) is a cross-sectional view of a main part of the film body.

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

FIG. 1 is a perspective view showing the overall configuration and internal structure of the liquid lead-acid battery (hereinafter, also simply referred to as “lead-acid battery”) according to the embodiment. As shown in FIG. 1, the lead-acid battery 1 according to the present embodiment includes an electric tank 2 having an open upper surface and a lid 3 for closing the opening of the electric tank 2. The battery case 2 and the lid 3 are made of polypropylene, for example. The lid 3 is provided with a negative electrode terminal 4, a positive electrode terminal 5, and a liquid port plug 6 for closing the liquid injection port provided in the lid 3.

Inside the battery case 2, an electrode group 7, a negative electrode column 8 connecting the electrode group 7 to the negative electrode terminal 4, a positive electrode column (not shown) connecting the electrode group 7 to the positive electrode terminal 5, dilute sulfuric acid, etc. Electrolyte and is stored.

In one embodiment, the lead-acid battery 1 has a width dimension of D or more in the category specified in JIS D5301. The width dimension of the lead storage battery 1 may be, for example, D, E, F, G or H in the classification defined in JIS D5301.

In one embodiment, the lead-acid battery 1 has a width dimension of LBN0 or more or LN0 or more in the category specified in EN 50342-2. The width dimension of the lead-acid battery 1 may be, for example, LBN0 to 6 or LN0 to 6 in the classification specified in EN 50342-2.

The lead-acid battery 1 has a width dimension of 170 mm or more in one embodiment. The width dimension of the lead storage battery 1 may be, for example, 175 mm or more or 180 mm or more, or 280 mm or less or 225 mm or less.

FIG. 2 is a perspective view showing the electrode group 7. As shown in FIG. 2, the electrode group 7 includes a plate-shaped negative electrode plate 9 containing metal lead (Pb) as an active material, a plate-shaped positive electrode _{plate 10 containing lead dioxide (PbO 2} ) as an active material, and a negative electrode. A separator 11 arranged between the plate 9 and the positive electrode plate 10 is provided. The electrode group 7 has a structure in which a plurality of negative electrode plates 9 and positive electrode plates 10 are alternately laminated in a direction substantially parallel to the opening surface of the battery case 2 via a separator 11. That is, the negative electrode plate 9 and the positive electrode plate 10 are arranged so that their main surfaces extend in the direction perpendicular to the opening surface of the battery case 2.

The separator 11 is formed in a bag shape so as to accommodate, for example, the negative electrode plate 9. Examples of the material forming the separator 11 include polyethylene (PE), polypropylene (PP) and the like. The separator 11 may be one in which inorganic particles _{such as SiO 2} and Al ₂ O ₃ are attached to a woven fabric, a non-woven fabric, a porous film or the like formed of these materials.

The thickness of the separator 11 is preferably 0.1 mm to 0.5 mm, more preferably 0.2 mm to 0.3 mm. When the thickness of the separator 11 is 0.1 mm or more, the strength of the separator can be ensured. When the thickness of the separator 11 is 0.5 mm or less, an increase in the internal resistance of the battery can be suppressed.

The average pore size of the separator 11 is preferably 10 nm to 500 nm, more preferably 30 nm to 200 nm. When the average pore size of the separator 11 is 10 nm or more, sulfate ions can be suitably passed through and the diffusion rate of sulfate ions can be ensured. When the average pore diameter of the separator 11 is 500 nm or less, the growth of lead dendrites is suppressed and short circuits are less likely to occur.

The ears 9a of the plurality of negative electrode plates 9 are collectively welded by the negative electrode side strap 12. Similarly, the ears 10a of the plurality of positive electrode plates 10 are collectively welded by the positive electrode side strap 13. Then, the negative electrode side strap 12 and the positive electrode side strap 13 are connected to the negative electrode terminal 4 and the positive electrode terminal 5 via the negative electrode column 8 and the positive electrode column, respectively.

FIG. 3 is a schematic cross-sectional view showing a cross section seen along the line I-I in FIG. As shown in FIG. 3, a film body 14 is provided between the negative electrode plate 9 and the separator 11. In the present embodiment, the film body 14 is provided in close contact with the negative electrode plate 9 so as to cover the surface of the negative electrode plate 9.

The film body 14 may be in the form of a sheet or a bag, for example. When the film body 14 is in the form of a sheet, the film body 14 covers the surface of the negative electrode plate 9 so as to be wound around the negative electrode plate 9. When the film body 14 has a bag shape, the negative electrode plate 9 is housed in the film body 14.

FIG. 4 is a plan view showing the negative electrode plate 9. As shown in FIG. 4, the negative electrode plate 9 has a substantially rectangular planar shape, a lattice body 9b formed of a lead alloy, and a substantially rectangular planar shape, and the negative electrode plate 9 is formed from one side of the lattice body 9b. It is provided with an ear portion 9a protruding outward, an active material (not shown) filled in the lattice body 9b, and a film body 14 provided on the surface of the negative electrode plate 9 so as to cover the active material.

The width W of the negative electrode plate 9 (the length of the side of the negative electrode plate 9 where the selvage portion 9a is provided) is preferably 120 mm or more, more preferably 130 mm or more, and further, from the viewpoint of further suppressing stratification of the electrolytic solution. It is preferably 140 mm or more.

The film body 14 preferably includes a film body having pores of an inorganic non-woven fabric, an organic woven fabric, an organic non-woven fabric, or a porous film (porous film body). The film body 14 is preferably hydrophilic. Examples of the material for forming the inorganic non-woven fabric include a material capable of forming a hydrophilic group such as a −OH group in the electrolytic solution, and specific examples thereof include SiO ₂ . When such an inorganic non-woven fabric is used, hydrophilic treatment becomes unnecessary.

When an organic woven fabric, an organic non-woven fabric or a porous film is used, a hydrophilic film is preferably formed on these surfaces. Examples of materials for forming an organic woven fabric, an organic non-woven fabric or a porous film include polypropylene, cellulose, polyethylene, nylon, aramid, polyester and the like. The organic woven fabric, the organic non-woven fabric, or the porous film is subjected to a hydrophilic treatment (a hydrophilic treatment different from the treatment for providing the hydrophilic film described later) even if it is untreated (the one not surface-treated). However, from the viewpoint of shortening the process, untreated one is preferably used.

FIG. 5A is a plan view of a main part showing a part P of the negative electrode plate 9 of FIG. 4, and shows a case where the film body 14 contains an organic non-woven fabric. In this case, as shown in FIG. 5A, the membrane body 14 has a structure in which filamentous fibers are irregularly entangled, thereby forming pores.

FIG. 5B is a cross-sectional view of a main part of the film body 14 of FIG. 5A. As shown in FIG. 5B, when the film body 14 contains an organic non-woven fabric (or an organic woven fabric or a porous film), the film body 14 further includes a hydrophilic film 17 containing a hydrophilic material 15 and a holding body material 16. The hydrophilic coating 17 is formed on a base material 18 which is an organic non-woven fabric (or an organic woven fabric or a porous film).

The mass ratio of the hydrophilic material 15 to the holding material 16 (hydrophilic material: holding material) is preferably 90:10 to 70:30 in terms of solid content when the hydrophilic material 15 is silica, more preferably. Is 86:14 to 74:26, more preferably 82:18 to 78:22. When the hydrophilic material 15 is alumina, the mass ratio (hydrophilic material: retention resistant material) is preferably 96: 4 to 84:16, more preferably 93: 7 to 87:13, and further preferably 91: 9. ~ 89:11.

Here, the hydrophilic coating 17 is formed to increase the interaction with sulfate ions and further suppress the stratification of the electrolytic solution, but it can also be an obstacle that inhibits the behavior of sulfate ions. Such obstacles can reduce the diffusion rate of sulfate ions and increase the internal resistance of lead-acid batteries. Further, it is considered that the hydrophilic film 17 supplies the sulfate ions collected by adsorption to the electrode, and the efficiency of supplying the sulfate ions from the hydrophilic film to the electrode affects the battery performance such as high rate discharge performance and charge acceptability. .. Therefore, it is preferable to select the configuration of the hydrophilic coating 17 as described later from the viewpoint of excellent other battery performance such as internal resistance of the lead storage battery in addition to stratification of the electrolytic solution.

The hydrophilic material 15 is preferably an inorganic material because it does not dissolve even when immersed in an acidic aqueous solution and maintains hydrophilicity for a long period of time due to a chemical interaction with sulfate ions. Examples of such an inorganic material include silica (SiO _{2 ) such as hydrophilic silica particles (coloidal silica), alumina (Al 2} O ₃ ) such as hydrophilic alumina sol, BaSO ₄ , TiO _{2, and the} like.

The hydrophilic material 15 preferably comprises a simple substance of silica, a simple substance of alumina, or a mixture of silica and alumina. Since colloidal silica uses alcohol as a dispersion medium and alumina sol uses water as a dispersion medium, these can be easily mixed to obtain a mixture. More specific examples of these inorganic materials include colloidal silica IPA-ST-UP, IPA-ST, ST-OXS, ST-K2 and LSS-35 manufactured by Nissan Chemical Industries, Ltd., and manufactured by Nissan Chemical Industries, Ltd. Alumina sol AS-200 and the like can be mentioned.

The colloidal silica, the specific surface area is preferably used particles is 130m ² / g~1000m ² / g. Assuming that the shape of such colloidal silica is spherical, its particle size is 2 nm to 20 nm. The alumina sol, specific surface area is preferably used particles is 200m ² / g~400m ² / g. Assuming that the shape of such alumina particles is plate-like, their dimensions (length, width and height) are, for example, about 10 nm × 10 nm × 100 nm.

As the holder material 16, an organic material or an inorganic material can be used. Examples of the organic material include an organic low molecular weight material such as acrylamide, and an organic polymer material such as polyethylene glycol and polyvinyl alcohol. Examples of inorganic materials include materials that can retain hydrophilic materials by heating, such as acrylamide, silica sol or silane coupling agents.

Among these, from the viewpoint of excellent long-term stability in an acidic aqueous solution, the retainer material is preferably acrylamide, silica sol or a silane coupling agent. The silane coupling agent is particularly preferably used because it has a high degree of freedom in selecting the functional groups constituting the silane coupling agent and the orientation of the retainer material can be easily controlled by the type of the functional group (details will be described later).

Specific examples of the silica sol include Corcourt PX of Corcote Co., Ltd. The silane coupling agent may be a silane coupling agent commercially available from Shin-Etsu Chemical Co., Ltd. or the like. Many silane coupling agents are actually classified as organic materials, but in this specification, they are described as inorganic materials because they are used to impart hydrophilic functional groups to the membrane body. ..

The retainer material 16 is selected, for example, as follows, depending on the type of functional group present on the surface of the base material 18. When the base material 18 is untreated (not surface-treated), it is considered that many hydrophobic functional groups such as methyl group and methylene group are present on the surface of the base material 18. In that case, if a silane coupling agent (retaining material) having a functional group such as a vinyl group, a methacryloyl group, an acryloyl group, or a styryl group is selected, a vinyl group, a methacryloyl group, an acryloyl group, a styryl group or the like is used as a base material. It is considered that the silanol groups generated by the hydrolysis reaction are oriented toward the surface side of the base material 18 and are oriented toward the surface opposite to the base material 18.

On the other hand, when the base material 18 is treated with hydrophilicity, it is considered that many hydrophilic functional groups such as hydroxyl groups (−OH groups), carboxyl groups and amino groups are present on the surface of the base material 18. In that case, if a silane coupling agent (retaining material) having an amino group, an epoxy group, etc. is selected, the amino group, the epoxy group, etc. react with the functional group on the surface of the base material 18, which is generated by hydrolysis. It is considered that the silanol group is oriented on the side opposite to the surface of the base material 18. The amino group is particularly preferably used because it easily forms a hydrogen bond with the hydroxyl group and easily orients the silanol group toward the outermost surface side of the hydrophilic film.

By selecting the retainer material 16 according to the type of functional group on the surface of the base material 18 in this way, the orientation of the functional group in the retainer material can be controlled, and the outermost surface of the hydrophilic film (in contact with the electrolytic solution) can be controlled. A silanol group can be placed on the surface).

As a result, the amount of hydrophilic functional groups such as -OH groups present on the surface of the hydrophilic film 17 is large, and the hydrophilicity of the hydrophilic film 17 is increased, so that the interaction between the hydrophilic film 17 and sulfate ions works greatly. It becomes easier to eliminate the occurrence of the concentration gradient of sulfuric acid in the electric tank 2, and it is also possible to improve the supply rate of sulfate ions to the electrode.

Among the above combinations, the combination of the untreated base material 18 and the silane coupling agent having a functional group such as a vinyl group, a methacryloyl group, an acryloyl group, or a styryl group does not require the hydrophilic treatment of the base material 18. Therefore, it is particularly preferably used because the process can be shortened.

The contact angle of the hydrophilic coating 17 with water or sulfuric acid is, for example, 10 ° or less. However, when a hydrophilic material having a high adsorption power for sulfate ions such as Al ₂ O ₃ is used, if a level of hydrophilicity having a contact angle of about 30 ° is obtained, the adsorption of sulfate ions can be performed. The contact angle does not necessarily have to be 10 ° or less because the synergistic effect of

The hydrophilic film 17 can be obtained, for example, by applying a hydrophilic paint on a film body, heating the film, and thermosetting the film. The hydrophilic coating material contains, for example, the above-mentioned hydrophilic material, the above-mentioned holder material, and a solvent.

The hydrophilic material and the retainer material each exist in a state in which solid components are dispersed in a dispersion medium at a constant concentration. From the viewpoint of being able to suitably produce a hydrophilic paint, the hydrophilicity is such that the mass ratio of the solid component of the hydrophilic material to the solid component of the holder material (hydrophilic material: holder material) is 90: 10 to 70:30. It is preferable to mix the dispersion containing the material and the dispersion containing the holding material. Next, after mixing the dispersion liquid containing the hydrophilic material and the dispersion liquid containing the retainer material, the total concentration of the solid components of the hydrophilic material and the retainer material is the dispersion obtained by mixing (mixed dispersion). Liquid) The mixed dispersion is diluted with a solvent so that the total amount is 0.5% by mass to 5% by mass. When the concentration of the solid component in the mixed dispersion is 0.5% by mass or more, the thickness of the hydrophilic coating can be made uniform. When the concentration of the solid component in the mixed dispersion is 5% by mass or less, a hydrophilic film can be suitably formed.

The solvent used to dilute the mixed dispersion of the hydrophilic material and the retainer material preferably has good dispersibility and compatibility of the hydrophilic material and the retainer material and volatilizes during thermal curing. It is an easy solvent. Considering the heat resistance of the film body, the boiling point of the solvent is preferably 100 ° C. or lower. Examples of the solvent satisfying these conditions include alcohol-based solvents, water and the like, and more preferably water, methanol, ethanol and isopropyl alcohol.

In the above embodiment, the hydrophilic film 17 is formed by wet hydrophilic treatment to impart hydrophilicity to the film body 14, but in other embodiments, the film body 14 is subjected to dry hydrophilic treatment such as sulfonation treatment and fluorine treatment. Hydrophilicity may be imparted. From the viewpoint of maintaining the hydrophilicity of the film body 14, it is preferable to use an inorganic non-woven fabric, or an organic woven fabric, an organic non-woven fabric or a porous film to which hydrophilicity has been imparted by a wet hydrophilic treatment.

The thickness of the hydrophilic coating 17 is preferably 10 nm to 1000 nm, more preferably 10 nm to 500 nm, and even more preferably 100 nm to 400 nm. When the thickness of the hydrophilic film is 10 nm or more, the hydrophilic film is likely to be formed uniformly, and the effect of adsorbing and retaining sulfate ions is further enhanced. When the thickness of the hydrophilic film is 1000 nm or less, the internal resistance of the battery can be suppressed. The thickness of the hydrophilic film is calculated by observing the cross section of the hydrophilic film by SEM. The thickness of the hydrophilic coating can be adjusted by adjusting the concentration of the hydrophilic coating material or by adjusting the pressure for removing the excess coating material after applying the hydrophilic coating material on the substrate.

In the film body 14 having pores as described above, the average pore diameter is 15 μm or less from the viewpoint of suppressing the stratification of the electrolytic solution. The average pore diameter of the film body 14 is preferably 12 μm or less, 10 μm or less, 7 μm or less, 5 μm or less, 3 μm or less, or 2 μm or less from the viewpoint of further suppressing the stratification of the electrolytic solution. The average pore diameter of the membrane body 14 may be, for example, 1 μm or more.

The average pore diameter of the membrane is X corresponding to the median value between the minimum value and the maximum value on the Y axis (pore volume or pore specific surface area) of the distribution curve in the integrated pore diameter distribution measured by the mercury intrusion method. It is calculated as the median diameter, which is the value of the axis (pore diameter). The average pore size of the membrane can be measured by, for example, Autopore IV 9500 manufactured by Shimadzu Corporation.

The porosity of the film body 14 is 93% or less, preferably 92% or less, more preferably 91% or less, still more preferably 90% or less, from the viewpoint of suppressing stratification. The porosity of the membrane body 14 is preferably 80% or more, more preferably 82% or more, still more preferably 84% or more, from the viewpoint of ensuring the diffusibility of sulfate ions and increasing the space for retaining sulfate ions. , Especially preferably 85% or more. The porosity of the membrane body is calculated from the actual volume and the apparent volume of a sample cut into a rectangular parallelepiped shape of an appropriate size from the membrane body according to the following formulas (1) to (3).
Porosity (%) = {1- (actual volume / apparent volume)} x 100 ... (1)
Actual volume (cm ³ ) = measured weight (g) / density (g / cm ³ ) ... (2)
Apparent volume (cm ³ ) = length (cm) x width (cm) x thickness (cm) ... (3)
The measured values are used for the length, width, and thickness of the sample when calculating the apparent volume.

By providing the film body 14 as described above between the negative electrode plate 9 and the separator 11, the accumulation of sulfate ions in the lower part of the electric tank 2 can be suppressed, and the stratification of the electrolytic solution can be suppressed. In other words, by providing the membrane body 14, the concentration of sulfate ions inside the electric tank 2 can be kept uniform. By providing such a film body 14 separately from the separator 11 in the vicinity of the negative electrode plate 9 than the separator 11, for example, a higher degree of suppression of stratification is achieved as compared with the case where the separator 11 is subjected to a treatment for suppressing stratification. The effect is obtained.

The present inventors consider the reason why the stratification of the electrolytic solution is suppressed by providing the film body 14 as follows. That is, the aggregate of sulfate ions generated in the charging reaction becomes high-concentration particles while being divided by the pores of the membrane body 14, and slowly precipitates in the electrolytic solution. When the membrane body 14 having a specific average pore diameter and porosity is provided, the sedimentation rate of sulfate ions is reduced as compared with the case where the membrane body 14 is not provided, so that stratification can be suppressed.

The structure of the pores in the film body 14 may be a regular structure, for example, between the fibers of the organic woven fabric, or an irregular structure, for example, between the fibers of the organic non-woven fabric. It may be a structure.

When charging with a large current as in ISS vehicle applications, a large amount of sulfate ions are released from the electrode plate, so the higher the sulfate ion retention capacity of the membrane body 14, the more preferable. When the film body 14 contains an inorganic non-woven fabric, an organic woven fabric, or an organic non-woven fabric, the fiber diameter of the fibers constituting them is preferably 10 μm or less, more preferably 5 μm or less. When the fiber diameter is 10 μm or less, the specific surface area of the membrane body 14 becomes large and the space for holding sulfate ions can be increased, so that the sulfate ion holding capacity of the membrane body 14 can be further improved. can. The fiber diameter is preferably 1 μm or more from the viewpoint of suppressing fiber breakage, tearing of the film body, and ensuring durability.

The thickness of the film body 14 is preferably 0.3 mm or less, more preferably 0.25 mm or less, still more preferably 0.2 mm or less, and particularly preferably 0.15 mm or less, from the viewpoint of suppressing an increase in internal resistance. .. The thickness of the membrane body 14 is, for example, 0.03 mm or more from the viewpoint of the ability to prevent the precipitation of sulfate ions, the influence on the battery reaction, the strength, and the like. When the film body 14 contains an inorganic non-woven fabric, an organic woven fabric, or an organic non-woven fabric, the thickness of the film body 14 is determined according to the thickness of the fibers constituting them. When the membrane body 14 includes a porous membrane, the thickness of the membrane body 14 is determined according to the pore size, material, and the like of the porous membrane.

Basis weight of the film body 14, from the viewpoint of compatibility between the suppression of stratification suppressing the internal resistance increase, preferably ^{30g / m 2 ~50g / m 2} , more preferably ^{35g / m 2 ~50g / m 2} , more preferably is a ^{40g / m 2 ~50g / m 2} . The basis weight is calculated as the mass per unit area of the film body 14.

In the above embodiment, the film body 14 covers all of the main surface (the surface facing the separator 11), the side surface, and the bottom surface of the negative electrode plate 9 and is provided so as to be in contact with the surfaces thereof (in close contact with each other). However, in another embodiment, the film body may be provided between the negative electrode plate 9 and the separator 11 so as to be separated from the negative electrode plate 9. In this case, the film body 14 may be provided, for example, on the surface of the separator 11 on the negative electrode side. From the viewpoint of further suppressing the stratification of the electrolytic solution, it is preferable that the film body 14 is provided so as to be in contact with (in close contact with) the surface of the negative electrode plate 9.

In the above embodiment, the film body 14 covers all of the main surface (the surface facing the separator 11), the side surface, and the bottom surface of the negative electrode plate 9, but in other embodiments, the film body is the main surface of the negative electrode plate 9. It may be provided so as to cover only the surface (the surface facing the separator 11).

In one embodiment, a hydrophilic film having the same structure as the hydrophilic film 17 contained in the film body 14 may be further formed on the surface of the separator 11 on the negative electrode plate 9 side.

<Example 1>
A paste-type plate was used in which a lead alloy lattice was filled with a paste prepared by kneading lead powder containing lead monoxide as a main component with dilute sulfuric acid. After that, an unmodified electrode plate was obtained through aging and drying steps. Incidentally, the positive electrode plate and the negative electrode plate which was not chemically converted is composed both divalent lead monoxide is lead compound (PbO), a mixture of such tribasic dilute lead sulfate _{(3PbO · PbSO 4 · H 2} O) ing. By chemical conversion, the unmodified substance of _{the positive electrode plate is oxidized to lead dioxide (PbO 2} ), and the unmodified substance of the negative electrode plate is reduced to spongy lead (Pb) to obtain an existing electrode plate (positive electrode plate, negative electrode plate). Was done.

An inorganic non-woven fabric (main component: SiO ₂ ) as shown in Table 1 was used as the film body and arranged on the negative electrode plate. A separator having a thickness of 0.25 mm and an average pore diameter of 30 nm to 200 nm is used as the separator, and dilute sulfuric acid is used as the electrolytic solution, and D size (JIS D5301; width: 173 mm, box) that is difficult to suppress stratification is used. A lead-acid battery having a rated capacity of 60 (Ah) having a height of 204 mm, a width of the negative electrode plate of 145 mm, and a height of the negative electrode plate (including the upper frame): 113 mm was produced.

(Calculation of average pore diameter)
The average pore size of the membrane was measured with Autopore IV 9500 manufactured by Shimadzu Corporation. The average pore diameter of the membrane is X corresponding to the median value between the minimum value and the maximum value on the Y axis (pore volume or pore specific surface area) of the distribution curve in the integrated pore diameter distribution measured by the mercury intrusion method. It was calculated as the median diameter, which is the value of the shaft (pore diameter).

(Evaluation of internal resistance)
The internal resistance of the lead-acid battery, which had been initially charged in advance, was evaluated using a 1 kHz AC mΩ meter. The specific evaluation criteria are shown by the value of the internal resistance when the internal resistance of the lead storage battery is 100 when the film body is not provided (Comparative Example 1). The value of the internal resistance is preferably less than 125, more preferably less than 120, and even more preferably less than 110. The results are shown in Table 1.

(DOD 17.5% life test (durability))
The DOD 17.5% life performance was measured as follows. First, the fully charged lead-acid battery was placed in a water tank in which the bath temperature was set to 25 ° C. ± 2 ° C. In the life test of DOD 17.5%, the following cycle units (a) to (g) were carried out in this order. In a 60 Ah lead-acid battery, the 20-hour rate current is 3 A. In addition, this test is a cycle test simulating how the lead-acid battery is used in the ISS vehicle, and it is judged that the life of the lead-acid battery has reached the end when the voltage of the lead-acid battery falls below 10.0V. The results are shown in Table 1.
(A) Discharge for 2.5 hours at 12A (corresponding to 4 times the 20-hour rate current).
The lower limit voltage for discharge was assumed to be larger than 10.0 V.
(B) Charge at 21A (equivalent to 7 times the 20-hour rate current) for 40 minutes.
The upper limit voltage for charging was 14.4 ± 0.05V.
(C) Discharge for 30 minutes at 21A (equivalent to 7 times the 20-hour rate current).
The lower limit voltage for discharge was assumed to be larger than 10.0 V.
(D) The above (b) and (c) are alternately repeated 85 times.
(E) Charge for 18 hours at 6A (equivalent to twice the 20-hour rate current).
CC (constant current) -CV (constant voltage) charging was performed, and the voltage during CV charging was 16.0V ± 0.05V.
(F) Discharge at 3A (20-hour rate current ± 1.0%) until the discharge end voltage reaches 10.5 ± 0.1V, check the capacity of the lead-acid battery, and the capacity reduction rate is smaller than 5%. It was confirmed.
(G) Charge for 24 hours at 15A (5 times the 20-hour rate current).
CC-CV charging was used, and the voltage during CV charging was 16.0V ± 0.05V.

(Evaluation of stratification suppression effect)
The effect of suppressing the stratification of the electrolytic solution was evaluated. Charging and discharging were repeated in the same manner as in the DOD 17.5% life test, and the difference in the vertical specific density of the electrolytic solution between the upper part and the lower part in the electric tank at the 255th cycle was used as an index of stratification. Specifically, the region from the upper end of the electrode group (upper end of the separator) to 1 cm above was defined as the upper part of the battery case, and the region from the lower end of the electrode group to 1 cm below was defined as the lower part of the battery case. The height of the electrode group (the length from the lower end of the electrode group to the upper end of the separator) was 116 mm. Then, the vertical specific density difference was calculated with the vertical specific density difference of the case where the film body was not provided (Comparative Example 1) as 100. The difference in relative density between the top and bottom is preferably less than 70, and more preferably less than 50. When the difference between the upper and lower specific densities was less than 70, it was judged that stratification was suppressed.

<Examples 2 to 6>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that the structure of the membrane was changed as shown in Table 1.

<Example 7>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that a film formed as follows was used instead of the inorganic non-woven fabric as the film.

First, an organic non-woven fabric made of untreated polypropylene (surface functional groups: -CH ₂ groups and -CH _{3 groups) was used as the base material of the film body.} Colloidal silica (SiO ₂ , IPA-ST-UP (manufactured by Nissan Chemical Industry Co., Ltd.)) and alumina sol (Al ₂ O ₃ , AS-200 (manufactured by Nissan Chemical Industry Co., Ltd.)) are used as hydrophilic materials. Silica sol (Colcoat PX (manufactured by Colcoat Co., Ltd.)) was used as the holder material.

Next, the mass ratio of the alumina sol to the colloidal silica in the hydrophilic material is 80:20 in terms of solid components (that is, 80% by mass of the alumina sol (Al) in the hydrophilic material. ₂O₃) Was included), the hydrophilic material and the retainer material were mixed. A hydrophilic coating material was prepared by diluting this mixed solution with ethanol so that the concentration of the solid component was 5% by mass.

After immersing the film body in this hydrophilic paint, the film body was pulled up at a speed of 156 mm / min. A film body coated with hydrophilic paint is sandwiched between Kim Towel (registered trademark), and the film body is heated to 60 ° C. after removing excess hydrophilic paint adhering to the film body by rolling the roller while applying pressure at about 5 kg from above. The solvent was removed by leaving it in a heated constant temperature bath for 1 hour. In this way, a hydrophilic film was formed on the film body. When the obtained hydrophilic film was observed by SEM, the film thickness was about 100 nm. Table 1 shows the average pore diameter, thickness, porosity and basis weight of the membrane.

<Examples 8 to 14>
A lead-acid battery was prepared and evaluated in the same manner as in Example 7 except that the structure of the film was changed as shown in Table 1.

<Example 15>
Inorganic non-woven fabric as shown in Table 1 is used as the film body, and the size of the lead storage battery is LN1 size (EN 50342-2. Width: 175 mm, box height: 190 mm. Negative electrode plate width: 143 mm, negative electrode. A lead-acid battery was produced and evaluated in the same manner as in Example 9 except that the height of the plate (including the upper frame) was changed to 100 mm.

<Examples 16 and 17>
A lead-acid battery was prepared and evaluated in the same manner as in Example 15 except that the inorganic non-woven fabric as shown in Table 1 was used as the film body.

<Example 18>
As the film body, instead of the inorganic non-woven fabric, a non-woven fabric (porous sheet; mixed fiber containing pulp, glass fiber and silica powder) composed of mixed fibers whose surfaces (both sides) are treated with fluorine gas is used. Made and evaluated a lead storage battery in the same manner as in Example 1.

<Comparative example 1>
A lead-acid battery was produced and evaluated in the same manner as in Example 1 except that the film body was not provided on the negative electrode plate.

<Comparative Examples 2 and 3>
A lead-acid battery was prepared and evaluated in the same manner as in Example 9 except that the inorganic non-woven fabric as shown in Table 2 was used as the film body.

<Comparative Examples 4 and 5>
A lead-acid battery was prepared and evaluated in the same manner as in Example 15 except that the inorganic non-woven fabric as shown in Table 2 was used as the film body.

<Reference Examples 1 to 3>
Inorganic non-woven fabric as shown in Table 2 is used as the film body, and the size of the lead-acid battery is mainly domestic B size (JIS D5301; width: 127 mm, box height: 203 mm. Negative plate width: 101 mm, negative electrode plate. A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that the height (including the upper frame) was changed to 103 mm.

From the above results, it was found that in the lead-acid battery having a predetermined width dimension, stratification was suppressed in the examples, whereas stratification was not suppressed in the comparative example. On the other hand, in the B size lead-acid batteries (Reference Examples 1 to 3), no significant difference was observed in the degree of suppression of stratification due to the porosity of the film body.

The present invention is not limited to the above examples, and includes various modifications. For example, the above-described embodiment has been described in detail in order to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to the embodiment including all the described configurations.

1 ... Lead-acid battery, 2 ... Battery, 9 ... Negative electrode plate, 10 ... Positive electrode plate, 11 ... Separator, 14 ... Membrane, 15 ... Hydrophilic material, 16 ... Holder material, 17 ... Hydrophilic coating, 18 ... Base material ..

Claims (6)

With the positive electrode plate
With the negative electrode plate
A separator arranged between the positive electrode plate and the negative electrode plate,
A film body arranged between the negative electrode plate and the separator,
With electrolyte
A positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank containing the electrolytic solution.
A liquid lead-acid battery having a width dimension of D or more in the category specified in JIS D5301.
The film body contains a base material and a hydrophilic film formed on the base material.
The base material is at least one selected from organic woven fabrics, organic non-woven fabrics and porous membranes.
The hydrophilic coating contains at least one hydrophilic material selected from alumina and silica and at least one holding material selected from acrylamide, silica sol and a silane coupling agent.
A liquid lead-acid battery having an average pore diameter of 15 μm or less and a porosity of 80% or more and 93% or less. With the positive electrode plate
With the negative electrode plate
A separator arranged between the positive electrode plate and the negative electrode plate,
A film body arranged between the negative electrode plate and the separator,
With electrolyte
A positive electrode plate, a negative electrode plate, a separator, a film body, and an electric tank containing the electrolytic solution.
A liquid lead-acid battery having a width dimension of LBN0 to 6 or LN0 to 6 in the category specified in EN 50342-2.
The film body contains a base material and a hydrophilic film formed on the base material.
The base material is at least one selected from organic woven fabrics, organic non-woven fabrics and porous membranes.
The hydrophilic coating contains at least one hydrophilic material selected from alumina and silica and at least one holding material selected from acrylamide, silica sol and a silane coupling agent.
A liquid lead-acid battery having an average pore diameter of 15 μm or less and a porosity of 80% or more and 93% or less. The film body has a less thickness and ^30g / ^{m 2 ~50g} / m 2 of basis weight 0.3 mm, liquid-type lead-acid battery according to claim 1 or 2. The liquid lead-acid battery according to any one of claims 1 to 3, wherein the hydrophilic material is a simple substance of alumina, a simple substance of silica, or a mixture of alumina and silica. The liquid lead-acid battery according to any one of claims 1 to 4, wherein the hydrophilic coating has a thickness of 10 nm to 1000 nm. A hydrophilic film containing at least one hydrophilic material selected from alumina and silica and at least one holding material selected from acrylamide, silica sol and a silane coupling agent is formed on the surface of the separator on the negative electrode plate side. The liquid lead-acid battery according to any one of claims 1 to 5 , which is further formed.

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