JP2019003838A - Liquid-type lead storage battery - Google Patents

Abstract

To achieve both of the suppression of stratification of electrolyte solution and the enhancement of an output performance of a lead storage battery.SOLUTION: A liquid-type lead storage battery comprises: a positive electrode plate 10; a negative electrode plate 9; a separator 11 disposed between the positive electrode plate 10 and the negative electrode plate 9; a film body 14 including a fiber and disposed between the negative electrode plate 9 and the separator 11; an electrolyte solution; and a battery case which contains the positive electrode plate 10, the negative electrode plate 9, the separator 11, the film body 14 and the electrolyte solution. The film body 14 has pores of 20 μm or less in average pore diameter. The film body 14 has a porosity of 60% or more. Of the fiber included in the film body 14, the fiber of 5 μm or more in fiber diameter accounts for 10% or more.SELECTED DRAWING: Figure 3

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 discharges 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 has become apparent as a factor in 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. This stratification becomes more pronounced as the ratio of the remaining capacity to the full charge capacity of the lead storage battery becomes smaller. Therefore, in the lead storage battery for an ISS vehicle used in an intermediate charge state in which the stirring effect of the electrolyte is difficult to be obtained, stratification is performed. Suppression is an important issue. In addition, in an ISS vehicle, high output performance is also required because the engine is frequently started and the power is supplied while the engine is stopped. That is, in an ISS vehicle, it is required to achieve both suppression of stratification and output performance.

  For such a problem, Patent Document 1 discloses a liquid lead that can maintain liquid retention and increase the life of a lead-acid battery by being included in a porous resin layer containing butyl rubber or the like on the electrode surface. A storage battery is described.

JP 2003-223890 A

  However, in the lead storage battery as described in Patent Document 1, there is still room for improvement in terms of coexistence of suppression of stratification of the electrolyte and output performance of the battery.

  Accordingly, an object of the present invention is to achieve both suppression of stratification of the electrolytic solution and improvement of the output performance of the battery.

  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. Therefore, as a result of further studies, the present inventors have obtained a membrane having pores having an average pore diameter of 20 μm or less, a porosity of 60% or more, and a fiber diameter of 5 μm or more. It was found that when a film body having a ratio of 10% or more is provided between the negative electrode and the separator, stratification of the electrolyte is suppressed and high output performance is obtained.

  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 containing fibers. A positive electrode plate, a negative electrode plate, a separator, a membrane body, and a battery case containing the electrolyte solution, and the membrane body has pores having an average pore diameter of 20 μm or less, and the porosity of the membrane body Is a liquid type lead-acid battery in which the proportion of fibers having a fiber diameter of 5 μm or more in the fibers contained in the film body is 10% or more.

  In one embodiment, the film body includes a nonwoven fabric containing organic fibers, a nonwoven fabric containing inorganic fibers, or a nonwoven fabric containing organic fibers and inorganic fibers.

  In one embodiment, the proportion of fibers having a fiber diameter of less than 5 μm in the fibers is 60% or more. In one embodiment, the proportion of fibers having a fiber diameter of 5 μm or more and 10 μm or less in the fibers is 10% or more.

  In one embodiment, the separator is a bag-shaped separator, and the negative electrode plate and the film body are accommodated in the separator.

  In one embodiment, the thickness of the film body is 0.3 mm or less.

  According to the present invention, it is possible to achieve both suppression of stratification of the electrolytic solution and improvement of the output performance of the battery.

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.

  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-acid battery 1 may have 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 may have 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 may have 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.

  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.

The separator 11 is formed in a bag shape, for example, and the negative electrode plate 9 and the film body 14 are accommodated in the separator 11. 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 or more and 0.5 mm or less, more preferably 0.2 mm or more and 0.3 mm or less. 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.

  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.

The film body 14 includes fibers. The film body 14 includes, for example, a nonwoven fabric. The nonwoven fabric may be a nonwoven fabric containing organic fibers, a nonwoven fabric containing inorganic fibers, or an organic / inorganic mixed nonwoven fabric containing organic fibers and inorganic fibers as fibers. Examples of the organic fiber include synthetic fibers such as polyethylene, polypropylene, polyester, nylon, and aramid. Examples of inorganic fibers include SiO ₂ fibers (glass fibers). The organic / inorganic mixed nonwoven fabric may further contain inorganic powder formed of SiO ₂ or the like.

  The film body 14 includes a plurality of types of fibers having different fiber diameters. It is considered that fine fibers having a fiber diameter of less than 5 μm (particularly about 1 μm or more and 2 μm or less) have an effect of suppressing the precipitation of sulfuric acid by increasing the specific surface area of the film body 14. A thick fiber having a fiber diameter of 5 μm or more (particularly about 5 μm or more and 10 μm or less) has the effect of increasing the diffusion coefficient of sulfuric acid by ensuring the strength of the film body 14 and increasing the space of the film body 14. Conceivable. The fiber diameter of the thick fiber is preferably at least 2.5 times the fiber diameter of the thin fiber. Thus, it is thought that coexistence with stratification suppression and output performance is attained because the film body 14 contains two or more types of a thin fiber and a thick fiber.

  The ratio of fibers having a fiber diameter of 5 μm or more in the total fibers contained in the membrane body 14 is 10% or more, and from the viewpoint of further increasing the diffusion coefficient of sulfuric acid, it is preferably 5% or more, more preferably 7%. Or more, more preferably 9% or more, particularly preferably 10% or more, and preferably 90% or less, more preferably 85% or less, still more preferably 80% or less, from the viewpoint of further suppressing the precipitation of sulfuric acid. Particularly preferably, it is 75% or less. The proportion of fibers having a fiber diameter of 5 μm or more and 10 μm or less is preferably in the above range.

  The proportion of fibers with a fiber diameter of less than 5 μm in the total fibers contained in the membrane body 14 is preferably 60% or more, more preferably 65% or more, and even more preferably 70%, from the viewpoint of further suppressing sulfuric acid settling. From the viewpoint of further increasing the diffusion coefficient of sulfuric acid, it is preferably 95% or less, more preferably 90% or less, still more preferably 85% or less, particularly preferably 80% or less. It is. The proportion of fibers having a fiber diameter of 1 μm or more and 2 μm or less is preferably in the above range.

  The ratio of fibers having a predetermined fiber diameter to the fibers contained in the film body is measured based on an SEM image obtained with a scanning electron microscope (for example, manufactured by Hitachi High-Technologies Corporation). Specifically, the diameter (length in the short direction of the fiber in the SEM image (shortest distance)) of 100 fibers in the SEM image is measured, and the fiber diameter distribution is obtained. Next, the ratio of the number of fibers having a predetermined fiber diameter to the total number of fibers measured is calculated.

  The film body 14 has pores. The average pore diameter of the membrane body 14 is 20 μm or less, and from the viewpoint of further suppressing the stratification of the electrolytic solution, preferably 19 μm or less, 18 μm or less, 17 μm or less, 16 μm or less, 15 μm or less, 14 μm or less, 13 μm or less, It is 12 μm or less, 11 μm or less, or 10 μm or less. The average pore diameter of the film body 14 is preferably 1 μm or more, 2 μm or more, or 3 μm or more from the viewpoint of further improving the output of the battery.

  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.

  By providing the film body 14 as described above between the negative electrode plate 9 and the separator 11, accumulation of high-concentration sulfuric acid 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, and the battery reaction can be prevented from being unevenly distributed, so that the life of the lead storage battery 1 can be improved. Become. 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 higher. An inhibitory effect is obtained.

The porosity of the film body 14 is 60% or more, and from the viewpoint of further ensuring the diffusibility of sulfate ions and further increasing the space for holding sulfate ions, it is preferably 65% or more, more preferably It is 70% or more, more preferably 75% or more, and particularly preferably 80% or more. The porosity of the film body is calculated from the actual volume and the apparent volume according to the following formulas (3) to (5) for a sample cut from the film body into a rectangular parallelepiped having an appropriate size.
Porosity (%) = {1− (actual volume / apparent volume)} × 100 (3)
Actual volume (cm ³ ) = actual value of weight (g) / density (g / cm ³ ) (4)
Apparent volume (cm ³ ) = length (cm) × width (cm) × thickness (cm) (5)
Note that measured values are used for the length, width, and thickness of the sample when calculating the apparent volume.

  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 viewpoints of sulfuric acid precipitation prevention ability, influence on battery reaction, strength, and the like. In the case where the film body 14 includes a nonwoven fabric, the thickness of the film body 14 is determined according to the thickness of the fibers constituting the nonwoven fabric.

  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).

<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. The fibers constituting the inorganic nonwoven fabric include two types of fibers A and B, a fiber A having a fiber diameter of 1 μm to 2 μm and a fiber B having a fiber diameter of 5 μm to 10 μm. The ratio is shown in Table 1. As the separator, a bag-like polyethylene separator having a thickness of 0.25 mm and an average pore diameter of 30 nm to 200 nm was used, and the negative electrode plate and the film body were accommodated in the separator. D size using dilute sulfuric acid as electrolyte (JIS D5301, width: 173 mm, box height: 204 mm, negative plate width: 145 mm, negative plate height (including upper frame)) : 113 mm.) A lead storage battery with a rated capacity of 60 Ah 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).

(Calculation of fiber diameter)
The fiber diameter of the fiber contained in the film body was measured based on an SEM image obtained with a scanning electron microscope manufactured by Hitachi High-Technologies Corporation. Specifically, the diameter (length in the short direction of the fiber (shortest distance) of the fiber in the SEM image) of 100 fibers in the SEM image was measured, and the fiber diameter distribution was obtained. Subsequently, the ratio of the number of fibers A having a fiber diameter of 1 μm or more and 2 μm or less and the number of fibers B having a fiber diameter of 5 μm or more and 10 μm or less to the total number of measured fibers was calculated.

(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.

(Evaluation of output performance)
The output performance was evaluated according to the VDA standard. That is, after measuring the initial performance of the lead-acid battery, it was recharged to a fully charged state over 2 to 96 hours, and then the following sequence test was performed. The following (1) to (5) are one unit, and the output performance was evaluated based on how many times the unit can be repeated until the voltage at the time of discharging (2) below falls below 7.2V. Table 1 shows relative values with the output performance set to 100 when no film body is provided (Comparative Example 1). When the film body is provided, the diffusion of sulfuric acid is delayed as compared with the case where the film body is not provided, and thus the output is reduced.
(1) Discharge at 45 A for 59 seconds.
(2) Discharge at 300 A for 1 second.
(3) Charge at 14.0 V for 60 seconds (maximum current value: 100 A).
(4) The above sequence tests (1) to (3) are repeated 3600 times.
(5) Pause for 48 hours.

  If the difference in specific gravity between the upper and lower parts is less than 70 and the output is 90 or more, it can be said that both suppression of stratification of the electrolyte and improvement of the output performance of the battery can be achieved. The upper / lower specific gravity difference is preferably less than 50. The output is preferably 95 or more.

(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) Charging 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) Discharge at 3 A (20 hour rate current ± 1.0%).
It was discharged until the final voltage reached 10.5 ± 0.1 V, and the capacity of the lead storage battery was confirmed, and it was confirmed that the capacity reduction rate was smaller than 5%.
(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.

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

<Examples 7 and 8>
Each example except that an organic / inorganic mixed nonwoven fabric (nonwoven fabric composed of mixed fibers containing porous sheet, pulp, glass fiber and silica powder) as shown in Table 1 was used as the film body instead of the inorganic nonwoven fabric. The lead acid battery was produced and evaluated in the same manner as in Example 1.

<Example 9>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that an organic nonwoven fabric (made of polypropylene) as shown in Table 1 was used instead of the inorganic nonwoven fabric as the film body.

<Example 10>
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 plate height (including upper frame): 100 mm) A lead-acid battery was produced and evaluated in the same manner as in Example 4 except that the change was made.

<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 Example 2>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that an inorganic nonwoven fabric (main component: SiO ₂ ) as shown in Table 1 was used as the film body.

<Comparative Example 3>
A lead-acid battery was prepared and evaluated in the same manner as in Example 1 except that an organic nonwoven fabric (made of polypropylene) as shown in Table 1 was used as the film body.

  From the above results, in the examples in which the average pore diameter of the film body provided between the negative electrode and the separator is 20 μm or less, the porosity is 60% or more, and the ratio of the fibers B is 10% or more, stratification suppression and output It can be seen that the performance is compatible. On the other hand, in Comparative Example 1 in which no film body is provided and in Comparative Example 3 in which the average pore diameter of the film body is 40 μm, stratification is not suppressed, and in addition, the ISS life (durability) is less than 1500, which is compared with the Example. And the service life was significantly shortened. In Comparative Example 2 in which the average pore diameter of the membrane was 1 μm and the ratio of fiber B was 5%, the output performance was less than 90. In Comparative Example 4 in which the porosity of the film body was 50%, the output performance was less than 90.

  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.

Claims (8)

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 including fibers;
An electrolyte,
A positive electrode plate, the negative electrode plate, the separator, the membrane body, and a battery case containing the electrolytic solution,
The membrane body has pores having an average pore diameter of 20 μm or less,
The porosity of the film body is 60% or more,
A liquid lead-acid battery in which the proportion of fibers having a fiber diameter of 5 μm or more in the fibers is 10% or more.   The liquid lead acid battery according to claim 1, wherein a ratio of fibers having a fiber diameter of less than 5 μm in the fibers is 60% or more.   The liquid lead acid battery according to claim 1 or 2, wherein a ratio of fibers having a fiber diameter of 5 µm to 10 µm in the fibers is 10% or more.   The lead acid battery as described in any one of Claims 1-3 with which the said film body is provided with the nonwoven fabric containing an organic fiber.   The liquid lead acid battery as described in any one of Claims 1-3 with which the said film body is provided with the nonwoven fabric containing an inorganic fiber.   The liquid lead acid battery as described in any one of Claims 1-3 with which the said film body is provided with the nonwoven fabric containing an organic fiber and an inorganic fiber.   The liquid lead acid battery according to any one of claims 1 to 6, wherein the separator is a bag-shaped separator, and the negative electrode plate and the film body are accommodated in the separator.   The liquid lead acid battery according to any one of claims 1 to 7, wherein the film body has a thickness of 0.3 mm or less.

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