JPWO2018105060A1 - Liquid lead-acid battery - Google Patents

Abstract

An object of the present invention is to suppress stratification of an electrolyte and improve durability in a liquid lead-acid battery having a predetermined size. In one aspect, the present invention provides a positive plate (10), a negative plate (9), a separator (11) disposed between the positive plate (10) and the negative plate (9), and a negative plate (9). ) And the separator (11), the membrane body (14), the electrolytic solution, the positive electrode plate (10), the negative electrode plate (9), the separator (11), the membrane body (14) and the electrolytic solution. A liquid lead-acid battery having a width dimension equal to or larger than D in a section defined in JIS D5301 and having a mean pore diameter of 15 μm or less. And the liquid lead acid battery whose porosity of a film body (14) is 93% or less is provided.

Description

  The present invention relates to a liquid 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, waiting for a signal, or the like is employed for the purpose of carbon dioxide emission regulation measures, fuel efficiency reduction, and the like. It has become so.

  Since no power is generated by the alternator 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. Moreover, since the power generation of the alternator is controlled even during traveling, the battery is in a state of insufficient charging.

When deep discharge and insufficient charging are repeated in a lead storage battery, stratification of the electrolyte occurs, which has become apparent as a cause of shortening the life of the lead storage battery. Here, stratification means that sulfate ions (SO ₄ ²⁻ ) and hydrogen sulfate ions (HSO ₄ ⁻ ) (hereinafter collectively referred to as “sulfate ions”) in the electrolytic solution are precipitated by repeated charge and discharge. A phenomenon in which a difference in the specific gravity of the electrolyte occurs between the top and bottom of the battery case. In particular, in a lead storage battery for an ISS vehicle, suppression of stratification is an important issue because it is used in an intermediate charging state in which the effect of stirring the electrolyte is difficult to obtain.

  For such a problem, Patent Document 1 describes a technique related to a separator for a liquid lead-acid battery, characterized in that an acid-resistant microporous resin film sheet and an acid-resistant nonwoven fabric sheet are laminated. Yes. The acid-resistant nonwoven 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 an average pore diameter is 20 to 100 μm.

JP 2013-206571 A

  However, in the acid-resistant non-woven fabric sheet described in Patent Document 1, since the average pore diameter is 20 to 100 μm, particularly when the battery size (width dimension) is large, sulfate ions generated in large quantities near the electrode plate during charging. May slip through the pores and settle, and the electrolyte may stratify.

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

  According to the study by the present inventors, water generated at the time of discharge promotes mixing of the electrolyte solution in the vicinity of the positive electrode, so that the effect of stratification is small, while there is no such effect in the vicinity of the negative electrode. Stratification is likely to occur. Further, stratification becomes more prominent as the size of the lead storage battery is larger. Therefore, as a result of repeated 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 Has been found to be possible to suppress the stratification of the electrolytic solution and improve the durability when the porosity is 93 μm or less and the porosity is 93% or less.

  That is, in one aspect, the present invention provides a positive electrode plate, a negative electrode plate, a separator disposed between the positive electrode plate and the negative electrode plate, a film body disposed between the negative electrode plate and the separator, and an electrolytic solution. A liquid-type lead-acid battery having a width dimension equal to or greater than D in a section defined in JIS D5301, and a battery body containing a positive electrode plate, a negative electrode plate, a separator, a film body, and an electrolytic solution Is a liquid lead-acid battery having pores with an average pore diameter of 15 μm or less and a membrane body porosity of 93% or less.

  In another aspect, the present invention provides a positive electrode plate, a negative electrode plate, a separator disposed between the positive electrode plate and the negative electrode plate, a film body disposed between the negative electrode plate and the separator, and an electrolytic solution. And a battery lead containing a positive electrode plate, a negative electrode plate, a separator, a film body, and an electrolytic solution, and liquid lead having a width dimension of LBN0 to 6 or LN0 to 6 in a section defined in EN 50342-2 The storage battery is a liquid lead storage battery in which the film body has pores having an average pore diameter of 15 μm or less, and the porosity of the film body is 93% or less.

  In one embodiment, the porosity of the film body 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 includes 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 membrane. The coating includes 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.

  In one aspect, the hydrophilic material comprises alumina alone, silica alone or a mixture of alumina and silica.

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

  In one embodiment, the film body includes an inorganic nonwoven fabric.

  In one embodiment, the surface of the separator on the negative electrode plate side includes 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.

  ADVANTAGE OF THE INVENTION According to this invention, in the liquid lead acid battery which has a predetermined magnitude | size, stratification of electrolyte solution can be suppressed and durability can be improved.

It is a perspective view showing the whole lead-acid battery composition and internal structure concerning 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 section which shows the arrow cross section along the II line | wire in FIG. It is a top view which shows the negative electrode plate which concerns on one Embodiment. (A) is a principal part top view which shows a part P of the negative electrode plate of FIG. 4, (b) is principal part sectional drawing of a film | membrane 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 an overall configuration and an internal structure of a liquid lead acid battery (hereinafter also simply referred to as “lead acid battery”) according to an embodiment. As shown in FIG. 1, the lead storage battery 1 according to the present embodiment includes a battery case 2 having an upper surface opened and a lid 3 for closing the opening of the battery case 2. The battery case 2 and the lid 3 are made of, for example, polypropylene. The lid 3 is provided with a negative electrode terminal 4, a positive electrode terminal 5, and a liquid port plug 6 that closes a liquid injection port provided in the lid 3.

  Inside the battery case 2 are an electrode group 7, a negative pole 8 connecting the electrode group 7 to the negative terminal 4, a positive pole (not shown) connecting the electrode group 7 to the positive terminal 5, dilute sulfuric acid, etc. The electrolyte solution is accommodated.

  In one embodiment, the lead storage battery 1 has a width dimension equal to or greater than D in a section defined in JIS D5301. The width dimension of the lead storage battery 1 may be D, E, F, G, or H, for example, as defined in JIS D5301.

  In one embodiment, the lead storage battery 1 has a width dimension of LBN0 or more or LN0 or more in a section defined in EN 50342-2. The width dimension of the lead storage battery 1 may be LBN0-6 or LN0-6, for example, as defined in EN 50342-2.

  In one embodiment, the lead storage battery 1 has a width dimension of 170 mm or more. 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-like negative electrode plate 9 containing metallic lead (Pb) as an active material, a plate-like positive electrode plate 10 containing lead dioxide (PbO ₂ ) as an active material, and a negative electrode A separator 11 disposed 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 stacked in a direction substantially parallel to the opening surface of the battery case 2 via separators 11. That is, the negative electrode plate 9 and the positive electrode plate 10 are arranged so that their main surfaces extend in a direction perpendicular to the opening surface of the battery case 2.

For example, the separator 11 is formed in a bag shape so as to accommodate the negative electrode plate 9. Examples of the material forming the separator 11 include polyethylene (PE) and polypropylene (PP). 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 nonwoven 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 secured. 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 diameter of the separator 11 is preferably 10 nm to 500 nm, more preferably 30 nm to 200 nm. When the average pore diameter of the separator 11 is 10 nm or more, sulfate ions can be suitably passed, 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 dendrite is suppressed, and a short circuit hardly occurs.

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

  FIG. 3 is a schematic cross-sectional view showing a cross-section taken along the line II 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, for example, a sheet shape or a bag shape. When the film body 14 has a sheet shape, 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 accommodated 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, and has 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. Ears 9a projecting 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 where the ear 9a of the negative electrode plate 9 is provided) is preferably 120 mm or more, more preferably 130 mm or more, from the viewpoint of further suppressing stratification of the electrolyte. Preferably it is 140 mm or more.

The film body 14 preferably includes an inorganic nonwoven fabric, an organic woven fabric, an organic nonwoven fabric, or a membrane body having a pore of a porous membrane (porous membrane body). The film body 14 preferably has hydrophilicity. Examples of the material for forming the inorganic nonwoven fabric include materials capable of forming hydrophilic groups such as —OH groups in the electrolytic solution, and specifically include SiO _{2 and the} like. When such an inorganic nonwoven fabric is used, hydrophilic treatment is not necessary.

  When an organic woven fabric, an organic nonwoven fabric or a porous membrane is used, a hydrophilic film is preferably formed on these surfaces. Examples of the material forming the organic woven fabric, the organic nonwoven fabric or the porous membrane include polypropylene, cellulose, polyethylene, nylon, aramid, polyester and the like. The organic woven fabric, the organic nonwoven fabric or the porous membrane is subjected to a hydrophilic treatment (hydrophilic treatment different from the treatment for providing a hydrophilic film to be described later) even if it is untreated (no surface treatment). However, an untreated one is preferably used from the viewpoint of shortening the process.

  Fig.5 (a) is a principal part top view which shows the part P of the negative electrode plate 9 of FIG. 4, and has shown the case where the film body 14 contains an organic nonwoven fabric. In this case, as shown in FIG. 5A, the film body 14 has a configuration in which thread-like fibers are irregularly entangled, thereby forming pores.

  FIG. 5B is a cross-sectional view of the main part of the film body 14 of FIG. As shown in FIG. 5B, when the film body 14 includes an organic nonwoven fabric (or organic woven cloth or porous film), the film body 14 further includes a hydrophilic film 17 including a hydrophilic material 15 and a holding material 16. The hydrophilic coating 17 is formed on a substrate 18 that is an organic nonwoven fabric (or organic woven fabric or porous membrane).

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

  Here, the hydrophilic film 17 is formed in order 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 an obstacle may reduce the diffusion rate of sulfate ions and increase the internal resistance of the lead acid battery. The hydrophilic coating 17 supplies sulfate ions collected by adsorption to the electrode, and the supply efficiency of sulfate ions from the hydrophilic coating to the electrode is considered to affect battery performance such as high rate discharge performance and charge acceptance. . Therefore, in addition to the stratification of the electrolytic solution, 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.

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

  The hydrophilic material 15 is preferably made of silica alone, alumina alone, 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 mixed together to easily 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., manufactured by Nissan Chemical Industries, Ltd. Alumina sol AS-200 etc. are 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, the particle diameter 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, the dimensions (vertical, horizontal and height) are, for example, about 10 nm × 10 nm × 100 nm.

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

  Among these, from the viewpoint of excellent long-term stability in an acidic aqueous solution, the support 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 functional groups constituting the silane coupling agent and can easily control the orientation of the support material depending on the type of the functional group (details will be described later).

  Specific examples of the silica sol include Colcoat Co., Ltd. Colcoat PX. The silane coupling agent may be a silane coupling agent commercially available from Shin-Etsu Chemical Co., Ltd. In addition, although silane coupling agents are actually many substances classified as organic materials, in this specification, they are described as inorganic materials because they are used to impart hydrophilic functional groups to the film body. .

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

  On the other hand, when the base material 18 is subjected to a hydrophilic treatment, it is considered that many hydrophilic functional groups such as a hydroxyl group (—OH group), a carboxyl group, and an amino group are present on the surface of the base material 18. In that case, when a silane coupling agent (support material) having an amino group, an epoxy group, or the like is selected, the amino group, epoxy group, etc. react with the functional group on the surface of the substrate 18, resulting in hydrolysis. It is considered that the silanol group is oriented on the side opposite to the surface of the substrate 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 of the hydrophilic film.

  Thus, by selecting the support material 16 according to the type of the functional group on the surface of the base material 18, the orientation of the functional group in the support material can be controlled, and the outermost surface of the hydrophilic film (in contact with the electrolyte) A silanol group can be arranged 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 sulfuric acid concentration gradient in the battery case 2, and the supply rate of sulfate ions to the electrode can be improved.

  Among the combinations as described above, the combination of the untreated substrate 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 substrate 18. Therefore, the process can be shortened, so that it is particularly preferably used.

The contact angle of the hydrophilic film 17 with respect to water or sulfuric acid is, for example, 10 ° or less. However, in the case of using a hydrophilic material having a high sulfate ion adsorbing power, such as Al ₂ O ₃ , if the hydrophilicity at a level where the contact angle is about 30 ° is obtained, the sulfate ion adsorption and Therefore, the contact angle is not necessarily 10 ° or less.

  The hydrophilic film 17 can be obtained, for example, by applying a hydrophilic paint on the film body and heating and thermally curing it. The hydrophilic paint contains, for example, the above hydrophilic material, the above support material, and a solvent.

  Each of the hydrophilic material and the holding material is present in a state where the solid component is dispersed in the dispersion medium at a constant concentration. From the viewpoint of suitably producing a hydrophilic coating, the hydrophilic ratio is such that the mass ratio of the solid component of the hydrophilic material to the solid component of the support material (hydrophilic material: support material) is 90:10 to 70:30. It is preferable to mix the dispersion liquid containing the material and the dispersion liquid containing the support material. Next, after the dispersion containing the hydrophilic material and the dispersion containing the holding material are mixed, the total concentration of the solid components of the hydrophilic material and the holding material is mixed to obtain a dispersion (mixed dispersion). Liquid) The mixed dispersion is diluted with a solvent so as to be 0.5 mass% to 5 mass% with respect to the total amount. When the concentration of the solid component in the mixed dispersion is 0.5% by mass or more, the thickness of the hydrophilic film can be made uniform. A hydrophilic film can be suitably formed as the density | concentration of the solid component in a mixed dispersion is 5 mass% or less.

  The solvent used for diluting the mixed dispersion of the hydrophilic material and the support material is preferably good in dispersibility and compatibility of the hydrophilic material and the support material, and volatilizes during the heat curing. Easy solvent. Considering the heat resistance of the film body, the boiling point of the solvent is preferably 100 ° C. or lower. As the solvent satisfying these conditions, alcohol solvents, water and the like are preferable, and water, methanol, ethanol and isopropyl alcohol are more preferable.

  In the above embodiment, the hydrophilic film 17 is formed by wet hydrophilic treatment to impart hydrophilicity to the membrane body 14. However, in other embodiments, the membrane 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 nonwoven fabric or an organic woven fabric, an organic nonwoven fabric or a porous membrane imparted with hydrophilicity by a wet hydrophilic treatment.

  The thickness of the hydrophilic film 17 is preferably 10 nm to 1000 nm, more preferably 10 nm to 500 nm, and still more preferably 100 nm to 400 nm. When the thickness of the hydrophilic film is 10 nm or more, the hydrophilic film is easily formed uniformly, and the effect of adsorbing and holding sulfate ions is further increased. When the thickness of the hydrophilic coating 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 with an SEM. The thickness of the hydrophilic coating can be adjusted by adjusting the concentration of the hydrophilic coating, or by adjusting the pressure when removing the extra coating after applying the hydrophilic coating on the substrate.

  In the film body 14 having the 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 film body 14 may be, for example, 1 μm or more.

  The average pore diameter of the membrane body is an X corresponding to an intermediate 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 cumulative 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 diameter of the membrane can be measured with, for example, Autopore IV 9500 manufactured by Shimadzu Corporation.

From the viewpoint of suppressing stratification, the porosity of the film body 14 is 93% or less, preferably 92% or less, more preferably 91% or less, and still more preferably 90% or less. The porosity of the membrane body 14 is preferably 80% or more, more preferably 82% or more, and still more preferably 84% or more, from the viewpoint of ensuring the diffusibility of sulfate ions and increasing the space for holding sulfate ions. Especially preferably, it is 85% or more. The porosity of the film body is calculated from the actual volume and the apparent volume according to the following formulas (1) to (3) for a sample cut from the film body into a rectangular parallelepiped having an appropriate size.
Porosity (%) = {1− (actual volume / apparent volume)} × 100 (1)
Actual volume (cm ³ ) = actual value of weight (g) / density (g / cm ³ ) (2)
Apparent volume (cm ³ ) = length (cm) × width (cm) × thickness (cm) (3)
Note that 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, accumulation of sulfate ions in the lower part of the battery case 2 can be suppressed, and stratification of the electrolytic solution can be suppressed. In other words, by providing the film body 14, the concentration of sulfate ions inside the battery case 2 can be kept uniform. By providing such a film body 14 in the vicinity of the negative electrode plate 9 rather than the separator 11 separately from the separator 11, for example, compared with the case where the separator 11 is subjected to a treatment for suppressing stratification, the stratification is further suppressed. An 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, an aggregate of sulfate ions generated by the charging reaction is divided by the pores of the film body 14 to become high-concentration particles and slowly settles in the electrolytic solution. When the film 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 film 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 that occurs between fibers of an organic woven fabric, for example, or an irregular structure that occurs between fibers and fibers of an organic nonwoven fabric, for example. It may be a structure.

  When charging with a large current as in an ISS vehicle application, a large amount of sulfate ions are released from the electrode plate. When the film body 14 includes an inorganic nonwoven fabric, an organic woven fabric, or an organic nonwoven 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 is increased and the space for holding sulfate ions can be increased. Therefore, the ability of the membrane body 14 to retain sulfate ions can be further improved. it can. The fiber diameter is preferably 1 μm or more from the viewpoint of suppressing fiber breakage, tearing of the film body, etc., 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 film 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 nonwoven fabric, an organic woven fabric, or an organic nonwoven fabric, the thickness of the film body 14 is determined according to the thickness of the fiber which comprises them. When the film body 14 includes a porous film, the thickness of the film body 14 is determined according to the pore diameter, material, and the like of the porous film.

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 a mass per unit area of the film body 14.

  In the above embodiment, the film body 14 is provided so as to cover 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 to be in contact with (in close contact with) the surfaces. 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 on the surface of the separator 11 on the negative electrode side, for example. From the viewpoint of further suppressing the stratification of the electrolytic solution, the film body 14 is preferably 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. 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 configuration as the hydrophilic film 17 included 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 electrode plate in which a lead alloy lattice filled with a paste prepared by kneading lead powder mainly composed of lead monoxide with dilute sulfuric acid was used. Thereafter, an unformed electrode plate was obtained through aging and drying steps. The unformed positive electrode plate and negative electrode plate are both composed of a mixture of divalent lead compounds such as lead monoxide (PbO) and tribasic dilute lead sulfate (3PbO · PbSO ₄ · H ₂ O). ing. As a result of the conversion, the unformed material of the positive electrode plate is oxidized to lead dioxide (PbO ₂ ), and the unformed material of the negative electrode plate is reduced to spongy lead (Pb) to obtain an already formed electrode plate (positive electrode plate, negative electrode plate). It was.

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

(Calculation of average pore diameter)
The average pore diameter of the membrane was measured with Autopore IV 9500 manufactured by Shimadzu Corporation. The average pore diameter of the membrane body is an X corresponding to an intermediate 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 cumulative pore diameter distribution measured by the mercury intrusion method. The median diameter was calculated as the value of the axis (pore diameter).

(Evaluation of internal resistance)
The internal resistance of the lead-acid battery that had been initially charged in advance was evaluated using a 1 kHz AC mΩ meter. The specific evaluation criteria are indicated by the value of the internal resistance when the internal resistance of the lead storage battery when the film body is not provided (Comparative Example 1) is 100. 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 lead-acid battery that had been fully charged was placed in a water tank whose hot water 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 was a cycle test simulating the use of a lead storage battery in an ISS car, and it was determined that the life was reached when the voltage of the lead storage battery fell below 10.0V. The results are shown in Table 1.
(A) Discharge for 2.5 hours at 12 A (corresponding to 4 times the 20-hour current).
The discharge lower limit voltage was greater than 10.0V.
(B) Charging for 40 minutes at 21A (equivalent to 7 times the 20-hour current).
The charge upper limit voltage was 14.4 ± 0.05V.
(C) Discharge for 30 minutes at 21 A (corresponding to 7 times the 20 hour current).
The discharge lower limit voltage was greater than 10.0V.
(D) The above (b) and (c) are repeated 85 times alternately.
(E) Charged for 18 hours at 6A (equivalent to twice the 20 hour rate current).
CC (constant current) -CV (constant voltage) charging was used, and the voltage during CV charging was 16.0 V ± 0.05 V.
(F) 3A (20 hour rate current ± 1.0%) is discharged until the end-of-discharge voltage reaches 10.5 ± 0.1 V to confirm the capacity of the lead storage battery, and the capacity reduction rate is smaller than 5% It was confirmed.
(G) Charged for 24 hours at 15A (5 times the 20 hour current).
CC-CV charging was used, and the voltage during CV charging was 16.0 V ± 0.05 V.

(Evaluation of stratification control effect)
The effect of suppressing the stratification of the electrolyte was evaluated. Charging and discharging were repeated in the same manner as in the DOD 17.5% life test, and the difference in upper and lower specific gravity of the electrolyte solution at the upper and lower portions in the battery case at the 255th cycle was used as an index for stratification. Specifically, the region from the upper end of the electrode group (the upper end of the separator) to 1 cm above was the upper part in the battery case, and the region from the lower end of the electrode group to 1 cm below was the lower part in 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, when the film body was not provided (Comparative Example 1), the vertical specific gravity difference was calculated as 100, and the vertical specific gravity difference was calculated. The difference in specific gravity between the upper and lower sides is preferably less than 70, more preferably less than 50. When the difference in specific gravity between the upper and lower sides was less than 70, it was judged that stratification was suppressed.

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

<Example 7>
A lead storage battery was prepared and evaluated in the same manner as in Example 1 except that the film body prepared as follows was used in place of the inorganic nonwoven fabric as the film body.

First, an organic nonwoven fabric made of untreated polypropylene (surface functional groups: —CH ₂ group and —CH ₃ group) was used as a base material of the film body. As the hydrophilic material, using colloidal silica _{(SiO 2, IPA-ST-} UP ( Nissan Chemical Industries, Ltd.)) and alumina sol _{(Al 2 O 3, AS-} 200 ( manufactured by Nissan Chemical Industries, Ltd.)), Silica sol (Colcoat PX (manufactured by Colcoat Co.)) was used as the support material.

  Next, the mass ratio of alumina sol to colloidal silica in the hydrophilic material is 80:20 in terms of solid components (that is, 80 mass% alumina sol (Al ₂O₃) So that the hydrophilic material and the carrier material were mixed. A hydrophilic paint 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. After sandwiching the film body coated with a hydrophilic paint on Kim Towel (registered trademark) and rolling the roller while pressing with about 5 kg from above, the excess hydrophilic paint adhering to the film body is removed, and then the film body is heated to 60 ° C. The solvent was removed by placing in a heated thermostat 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 produced and evaluated in the same manner as in Example 7 except that the configuration of the film body was changed as shown in Table 1.

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

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

<Example 18>
As the film body, a non-woven fabric (porous sheet, mixed fiber containing pulp, glass fiber, and silica powder) composed of mixed fibers whose surfaces (both sides) were treated with fluorine gas was used instead of the inorganic non-woven fabric. Produced and evaluated the 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 nonwoven fabric as shown in Table 2 was used as the film body.

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

<Reference Examples 1-3>
The inorganic non-woven fabric as shown in Table 2 is used as the film body, and the size of the lead storage battery is mainly B size for domestic use (JIS D5301. Width: 127 mm, Box height: 203 mm. The width of the negative electrode plate: 101 mm, A lead storage battery was produced and evaluated in the same manner as in Example 1 except that the height (including the upper frame portion: 103 mm) was changed.

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

  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 ... Lead storage battery, 2 ... Battery case, 9 ... Negative electrode plate, 10 ... Positive electrode plate, 11 ... Separator, 14 ... Film body, 16 ... Hydrophilic material, 16 ... Holding body material, 17 ... Hydrophilic film, 18 ... Base material .

Claims (9)

A positive electrode plate;
A negative electrode plate;
A separator disposed between the positive electrode plate and the negative electrode plate;
A film body disposed between the negative electrode plate and the separator;
An electrolyte,
A battery case containing the positive electrode plate, the negative electrode plate, the separator, the film body, and the electrolyte;
A liquid lead-acid battery having a width dimension equal to or greater than D in the category defined in JIS D5301
The liquid body lead-acid battery, wherein the film body has pores having an average pore diameter of 15 μm or less, and the porosity of the film body is 93% or less. A positive electrode plate;
A negative electrode plate;
A separator disposed between the positive electrode plate and the negative electrode plate;
A film body disposed between the negative electrode plate and the separator;
An electrolyte,
A battery case containing the positive electrode plate, the negative electrode plate, the separator, the film body, and the electrolyte;
A liquid lead-acid battery having a width dimension of LBN0-6 or LN0-6 in the category defined in EN 50342-2,
The liquid body lead-acid battery, wherein the film body has pores having an average pore diameter of 15 μm or less, and the porosity of the film body is 93% or less.   The liquid lead acid battery according to claim 1 or 2, wherein a porosity of the film body is 80% or more. 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 any one of claims 1-3. The film body includes a base material and a hydrophilic film formed on the base material,
The substrate is at least one selected from an organic woven fabric, an organic nonwoven fabric and a porous membrane,
5. The hydrophilic coating according to claim 1, comprising 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. Liquid lead-acid battery according to one item.   The liquid lead acid battery according to claim 5, wherein the hydrophilic material is composed of alumina alone, silica alone, or a mixture of alumina and silica.   The liquid lead acid battery according to claim 5 or 6, wherein the hydrophilic coating has a thickness of 10 nm to 1000 nm.   The liquid lead acid battery according to any one of claims 1 to 4, wherein the film body includes an inorganic nonwoven fabric.   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 silane coupling agent is formed on the surface of the separator on the negative electrode plate side. The liquid lead acid battery as described in any one of Claims 1-8 currently formed.

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