JPWO2019021691A1 - Lead acid battery - Google Patents

Abstract

The lead storage battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution. The negative electrode plate includes a negative electrode electrode material containing a carbon material, and the carbon material includes a first carbon material having a particle diameter of 32 μm or more and a second carbon material having a particle diameter of less than 32 μm. The ratio R2/R1 of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material is 15 or more and 155 or less. A porous layer is arranged between the negative electrode plate and the positive electrode plate.

Description

  The present invention relates to a lead storage battery.

  Lead acid batteries are used in various applications such as in-vehicle and industrial applications. The lead acid battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution. The negative electrode plate includes a negative electrode material. A carbon material is added to the negative electrode material.

Lead-acid batteries are sometimes used in a state of insufficient charge called a partial charge state (PSOC). For example, in charge control and idling stop start (ISS), a lead acid battery is used in PSOC. Therefore, the lead storage battery is required to have excellent life performance (hereinafter, PSOC life performance) in a charge/discharge cycle under PSOC conditions.
Patent Document 1 proposes to add carbon black as a carbon material to the negative electrode plate in order to improve the PSOC life performance.

International publication 2013/005733 pamphlet

However, since carbon black easily aggregates in the negative electrode material and a conductive network is difficult to be formed, the improvement of PSOC life performance is still insufficient.
In addition, when charging and discharging are repeated under PSOC conditions, lead is dissolved in the electrolytic solution, a component containing lead permeates into the separator, and a dendrite of metallic lead grows from the negative electrode plate to the positive electrode plate. Short circuit (osmotic short circuit) may occur.

One aspect of the present invention is a lead acid battery,
The lead acid battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution,
The negative electrode plate includes a negative electrode material containing a carbon material,
The carbon material includes a first carbon material having a particle diameter of 32 μm or more and a second carbon material having a particle diameter of less than 32 μm,
A ratio of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material: R2/R1 is 15 or more and 155 or less,
The present invention relates to a lead storage battery in which a porous layer is arranged between the negative electrode plate and the positive electrode plate.

  In a lead acid battery, it is possible to suppress permeation short circuit and improve the PSOC life performance.

FIG. 1 is an exploded perspective view with a part cut away showing an external appearance and an internal structure of a lead storage battery according to an embodiment of the present invention.

  One aspect of the present invention is a lead storage battery, which includes a negative electrode plate, a positive electrode plate, and an electrolytic solution. The negative electrode plate includes a negative electrode electrode material containing a carbon material, and the carbon material includes a first carbon material having a particle diameter of 32 μm or more and a second carbon material having a particle diameter of less than 32 μm. The ratio R2/R1 of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material is 15 or more and 155 or less. A porous layer is arranged between the negative electrode plate and the positive electrode plate.

  When the above configuration is satisfied, permeation short circuit caused by the growth of dendrite of metallic lead is suppressed, and PSOC life performance is improved.

  Carbon materials having various powder resistances are known. It is known that the powder resistance of the powder material changes depending on the shape of the particles, the particle diameter, the internal structure of the particles, and/or the crystallinity of the particles. According to the conventional common general knowledge, the powder resistance of the carbon material is not directly related to the resistance of the negative electrode plate and is not considered to affect the PSOC life performance.

  On the other hand, in the above aspect of the present invention, the first carbon material and the second carbon material having different particle sizes are used in combination, and the powder resistance ratio R2/R1 of the first carbon material and the second carbon material is 15 to By controlling in the range of 155, high PSOC life performance can be obtained. It is presumed that this is because by controlling the powder resistance ratio R2/R1 within the above range, a conductive network is easily formed in the negative electrode material, and the formed conductive network is easily maintained. ..

  When a conductive network is formed in the negative electrode material, the negative electrode active material is easily oxidized at the time of discharging in the low resistance portion (near the carbon material) of the negative electrode plate, and at the time of charging, the surface of the negative electrode plate. At this point, lead ions contained in the electrolytic solution are reduced, metallic lead is easily deposited, and metallic lead dendrites are easily grown.

  Therefore, in the above aspect of the present invention, the porous layer is arranged between the negative electrode plate and the positive electrode plate. This suppresses permeation short circuit caused by the growth of metallic lead dendrites. However, arranging the porous layer increases the internal resistance. Therefore, it is considered that the PSOC life performance is deteriorated when the porous layer is arranged according to the conventional technical common sense.

  On the other hand, in the above aspect of the present invention, by using the first carbon material and the second carbon material while controlling their powder resistance ratio R2/R1 within the range of 15 to 155, the negative electrode plate and the positive electrode plate are used. Even if a porous layer is arranged between the two, the deterioration of PSOC life performance is suppressed. It is speculated that this is because the use of the first carbon material and the second carbon material in combination facilitates the formation of a conductive network in the negative electrode material. Further, when the porous layer is arranged, stratification of the electrolytic solution is suppressed. It is presumed that this is also one of the factors that suppress the deterioration of PSOC life performance.

  Further, when the porous layer is arranged between the negative electrode plate and the positive electrode plate, while controlling the powder resistance ratio R2/R1 in the range of 15 to 155, the specific surface area ratio S2/S1 and the porous layer described later are controlled. The charge acceptance performance can also be improved by adjusting the thickness of the battery.

(Porous layer)
A woven fabric or a non-woven fabric can be used for the porous layer. Nonwoven fabric is a mat in which fibers are intertwined without being woven. Woven or non-woven fabrics are mainly composed of fibers. For example, 60% by mass or more of the porous layer is formed of fibers. As the fibers constituting the woven or non-woven fabric, glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers such as polyethylene terephthalate fibers, etc.), pulp fibers and the like can be used. Of these, glass fibers (for example, non-woven fabric containing glass fibers) are preferable. In the case of glass fiber (for example, non-woven fabric containing glass fiber), the effect of improving the PSOC life performance and the effect of suppressing permeation short circuit can be obtained in good balance. Further, the non-woven fabric containing the glass fiber has the same electric resistance and density as the non-woven fabric containing the polyethylene fiber, is relatively inexpensive, and is easy to manufacture. The woven or non-woven fabric may contain components other than fibers, for example, acid-resistant inorganic powder, a polymer as a binder, and the like.

The porous layer may be arranged on the surface of the negative electrode plate or the positive electrode plate, but is preferably arranged on the surface of the negative electrode plate from the viewpoint of suppressing dendrite growth.
As a method for disposing the porous layer, for example, a woven cloth or a non-woven cloth is laid on the surface of the negative electrode plate or the positive electrode plate, or a bag body made of the woven cloth or the non-woven cloth is prepared, and the negative electrode plate or the positive electrode plate is bagged It can be stored in. A woven fabric or a non-woven fabric may be attached to the separator described later.

  One surface of the porous layer faces one surface of the negative electrode plate or the positive electrode plate, and the other surface of the porous layer faces one surface of the separator described later. When the porous layer is composed of a woven or non-woven fabric and the separator is composed of a microporous film described later, the other surface of the porous layer and one surface of the separator described later are porous in a region facing each other. The holes in the layer and the holes in the separator do not communicate with each other. Therefore, even in this region, the growth of dendrites from the negative electrode plate to the positive electrode plate is suppressed.

  The porous layer may be composed of one piece of woven cloth or non-woven cloth, or may be composed of a plurality of woven cloth or non-woven cloth stacked on each other. The thickness of the porous layer is, for example, 5 μm or more and less than 600 μm. The thickness of the porous layer is the thickness at a pressure of 19.6 KPa in a dry state containing no electrolytic solution.

The thickness of the porous layer is obtained by the following procedure.
The lead acid battery is disassembled, the porous layer is taken out, the sulfuric acid is removed by washing with water, and then dried. Then, 10 porous layers each having a size of 50 mm×50 mm are stacked to form a laminated body, and the thickness T of the laminated body under a pressure of 19.6 KPa is measured. The value of T/10 is the porous layer. Is calculated as the thickness per sheet.

From the viewpoint of suppressing permeation short circuit, the thickness of the porous layer is preferably 10 μm or more and 500 μm or less. When the thickness of the porous layer is 10 μm or more, the effect of suppressing the permeation short circuit due to the provision of the porous layer is further enhanced. When the thickness of the porous layer is 500 μm or less, an increase in internal resistance due to the arrangement of the porous layer and a decrease in battery performance (PSOC life performance, charge acceptance performance, etc.) due to it are suppressed. Further, when the thickness of the porous layer is 500 μm or less, a sufficient space for disposing the porous layer can be secured between the negative electrode plate and the positive electrode plate.
The thickness of the porous layer is more preferably 100 μm or more and 500 μm or less from the viewpoint of further suppressing the permeation short circuit while maintaining a high PSOC life performance.

The electric resistance of the porous layer is, for example, less than 0.0015 Ω·dm ² /sheet. The density of the porous layer is, for example, 0.15 to 1.5 g/cm ³ . The average fiber diameter of the glass fibers is, for example, about 10 to 20 μm.

(Carbon material)
The carbon material includes a first carbon material having a particle size of 32 μm or more and a second carbon material having a particle size of less than 32 μm. The first carbon material and the second carbon material are separated and distinguished by the procedure described below.

  Examples of each carbon material include carbon black, graphite, hard carbon, and soft carbon. Examples of carbon black include acetylene black, Ketjen black, furnace black, and lamp black. The graphite may be any carbon material having a graphite type crystal structure, and may be either artificial graphite or natural graphite.

The intensity of a peak appearing in 1300 cm ^-1 or 1350 cm ^-1 or less in the range of the Raman spectrum (D band) and 1550 cm ^-1 or 1600 cm ^-1 peak appearing in the range (G band) of the first carbon material Graphite has a ratio I _D /I _G of 0 or more and 0.9 or less.

  The ratio of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material: R2/R1 is 15 or more and 155 or less. The powder resistance ratio R2/R1 can be adjusted by changing the type, particle diameter, specific surface area, and/or aspect ratio of each carbon material used for producing the negative electrode material. As the first carbon material, for example, at least one selected from the group consisting of graphite, hard carbon, and soft carbon is preferable. In particular, the first carbon material preferably contains at least graphite. The second carbon material preferably contains at least carbon black. Using these carbon materials makes it easy to adjust the powder resistance ratio R2/R1.

  The powder resistance ratio R2/R1 is preferably 15 or more and 85 or less. In this case, while maintaining the high PSOC life performance, the charge acceptance performance is further improved, and the occurrence of penetration short circuit is further suppressed.

  The ratio S2/S1 of the specific surface area S2 of the second carbon material to the specific surface area S1 of the first carbon material is, for example, 10 or more and 400 or less. The specific surface area ratio S2/S1 is preferably 20 or more, more preferably 110 or more. Further, it is preferably 240 or less. These upper and lower limits can be arbitrarily combined. When the specific surface area ratio S2/S1 is 20 or more, many contact points between the carbon material and the negative electrode active material can be secured, and the charge acceptance performance can be improved even when the porous layer is arranged. When the specific surface area ratio S2/S1 is 20 or more and 240 or less, in the production of the negative electrode plate, a negative electrode paste having good properties is obtained, the filling property of the negative electrode paste into the negative electrode current collector is improved, and the negative electrode plate ( The reliability of the battery) can be improved. From the viewpoint of further improving the charge acceptance performance, the specific surface area ratio S2/S1 is more preferably 110 or more and 240 or less.

  The average aspect ratio of the first carbon material is, for example, 1 or more and 200 or less. The average aspect ratio of the first carbon material is preferably 1 or more, more preferably 1.5 or more. Further, it is preferably 100 or less, and more preferably 30 or less. These upper and lower limits can be arbitrarily combined. When the average aspect ratio of the first carbon material is 1.5 or more and 30 or less, PSOC life performance is further enhanced. It is considered that this is because when the average aspect ratio is in such a range, the conductive network is easily formed in the negative electrode material and the formed conductive network is easily maintained.

  Further, when the average aspect ratio of the first carbon material is 1.5 or more, outflow of the carbon material into the electrolytic solution due to repeated charging/discharging is suppressed, so that the effect of improving the PSOC life performance is further enhanced. be able to. Further, when the average aspect ratio of the first carbon material is 30 or less, it becomes easy to secure the adhesion between the active material particles, so that the occurrence of cracks in the negative electrode plate is suppressed and the deterioration of PSOC life performance can be suppressed. .

  When the average aspect ratio of the first carbon material is 1.5 or more, the larger the average aspect ratio of the first carbon material, the more likely the permeation short circuit will occur. This is because the larger the average aspect ratio of the first carbon material, the larger the area ratio of the first carbon material exposed on the surface of the negative electrode plate, and the dendrite of metallic lead grows in the vicinity of the low resistance first carbon material. It is presumed that this is because it becomes easier. Therefore, when the average aspect ratio of the first carbon material is 1.5 or more, the effect of suppressing the permeation short circuit by providing the porous layer is remarkably obtained.

  The content of the first carbon material in the negative electrode material is, for example, 0.05% by mass or more and 3.0% by mass or less. It is preferably 0.1% by mass or more. Further, it is preferably 2.0% by mass or less, and more preferably 1.5% by mass or less. These upper and lower limits can be arbitrarily combined. When the content of the first carbon material is 0.05% by mass or more, the effect of improving the PSOC life performance can be further enhanced. When the content of the first carbon material is 3.0% by mass or less, it becomes easy to secure the adhesion between the active material particles, so that the generation of cracks in the negative electrode plate is suppressed and the high PSOC life performance is further secured. It will be easier.

The content of the second carbon material in the negative electrode material is, for example, 0.03 mass% or more and 3.0 mass% or less. It is preferably 0.05% by mass or more. Further, it is preferably 1.0% by mass or less, and more preferably 0.5% by mass or less. These upper and lower limits can be arbitrarily combined. When the content of the second carbon material in the negative electrode material is 0.03 mass% or more and 3.0 mass% or less, PSOC life performance can be further improved.
The content of each carbon material in the negative electrode material is determined by the procedure (A-1) described later.

The method for determining or analyzing the physical properties of the carbon material will be described below.
(A) Analysis of carbon material (A-1) Separation of carbon material An existing fully-charged lead-acid battery was disassembled, the negative electrode plate was taken out, sulfuric acid was removed by washing with water, and vacuum drying (under a pressure lower than atmospheric pressure). To dry). Next, the negative electrode material is collected from the dried negative electrode plate and crushed. To 5 g of the ground sample, 30 mL of a 60 mass% concentration nitric acid aqueous solution is added and heated at 70°C. To this mixture are further added 10 g of disodium ethylenediaminetetraacetate, 30 mL of 28 mass% ammonia water, and 100 mL of water, and heating is continued to dissolve soluble components. The sample thus pretreated is collected by filtration. The collected sample is passed through a sieve with an opening of 500 μm to remove components having a large size, such as a reinforcing material, and the components that have passed through the sieve are collected as a carbon material.

  When the recovered carbon material is wet-sieved using a sieve having openings of 32 μm, the material remaining on the sieve is passed through the sieve without passing through the sieve eyes as the first carbon material. Let the thing be a 2nd carbon material. That is, the particle size of each carbon material is based on the size of the openings of the sieve. For wet sieving, JIS Z8815:1994 can be referred to.

  Specifically, the carbon material is placed on a sieve having openings of 32 μm, and the sieve is gently shaken for 5 minutes while sieving with ion-exchanged water. The first carbon material remaining on the sieve is collected from the sieve by pouring ion-exchanged water and separated from the ion-exchanged water by filtration. The second carbon material that has passed through the sieve is collected by filtration using a nitrocellulose membrane filter (opening 0.1 μm). The recovered first carbon material and second carbon material are each dried at a temperature of 110° C. for 2 hours. As the sieve having a mesh of 32 μm, a sieve having a sieve mesh having a nominal mesh of 32 μm, which is defined in JIS Z 8801-1:2006, is used.

  The content of each carbon material in the negative electrode material is determined by measuring the mass of each carbon material separated in the above procedure and calculating the ratio (mass %) of this mass in 5 g of the ground sample. Ask.

In the present specification, the fully charged state of the lead storage battery means, in the case of a liquid type battery, after performing constant current charging at a current of 0.2 CA until reaching 2.5 V/cell in a water tank at 25° C., Further, it is a state in which constant current charging is performed at 0.2 CA for 2 hours. Further, in the case of a control valve type battery, the fully charged state means constant current constant voltage charging of 2.23 V/cell at 0.2 CA in a 25° C. air chamber, and charging current during constant voltage charging. Is a state in which charging is completed when is less than 1 mCA.
In addition, in this specification, 1 CA is a current value (A) having the same numerical value as the nominal capacity (Ah) of the battery. For example, if the battery has a nominal capacity of 30 Ah, 1 CA is 30 A and 1 mCA is 30 mA.

(A-2) Powder Resistance of Carbon Material The powder resistance R1 of the first carbon material and the powder resistance R2 of the second carbon material are the first carbon material and the first carbon material separated in the procedure of (A-1) above. For each of the two carbon materials, 0.5 g of the sample was put into a powder resistance measuring system (MCP-PD51 type manufactured by Mitsubishi Chemical Analytech Co., Ltd.), and the pressure was 3.18 MPa, and JIS K 7194:1994 was specified. It is a value measured by the four-point probe method using a compliant low resistance resistivity meter (Loresta-GX MCP-T700, manufactured by Mitsubishi Chemical Analytech Co., Ltd.).

(A-3) Specific Surface Area of Carbon Material The specific surface area s1 of the first carbon material and the specific surface area s2 of the second carbon material are the respective BET specific surface areas of the first carbon material and the second carbon material. The BET specific surface area is obtained by the gas adsorption method using the BET formula using each of the first carbon material and the second carbon material separated in the procedure (A-1). Each carbon material is pretreated by heating at a temperature of 150° C. for 1 hour in a nitrogen flow. Using the pretreated carbon material, the BET specific surface area of each carbon material is determined by the following apparatus under the following conditions.
Measuring device: TriStar 3000 manufactured by Micromeritics
Adsorption gas: Nitrogen gas with a purity of 99.99% or more Adsorption temperature: Liquid nitrogen boiling point temperature (77K)
Calculation method of BET specific surface area: conforming to 7.2 of JIS Z 8830:2013

(A-4) Average Aspect Ratio of First Carbon Material The first carbon material separated by the procedure of (A-1) above is observed with an optical microscope or an electron microscope, and 10 or more arbitrary particles are selected. , Take a magnified picture of it. Next, the photograph of each particle is subjected to image processing to obtain the maximum diameter d1 of the particle and the maximum diameter D2 in the direction orthogonal to this maximum diameter d1, and by dividing d1 by d2, the aspect ratio of each particle is obtained. Ask. The average aspect ratio is calculated by averaging the obtained aspect ratios.

(Organic shrinkproofing agent)
The organic anti-shrink agent contained in the negative electrode material is an organic polymer containing a sulfur element, and generally contains one or more, preferably a plurality of aromatic rings in the molecule and contains a sulfur element as a sulfur-containing group. There is. Among the sulfur-containing groups, a stable form of a sulfonic acid group or a sulfonyl group is preferable. The sulfonic acid group may be present in an acid form or in a salt form such as Na salt.

  As the organic anti-shrink agent, for example, lignins may be used, or a synthetic organic anti-shrink agent may be used. As the synthetic organic shrinkproofing agent, a condensation product of an aromatic compound having a sulfur-containing group with formaldehyde may be used. Examples of the lignins include lignin, lignin derivatives such as ligninsulfonic acid or salts thereof (such as alkali metal salts such as sodium salts). The organic anti-shrink agent may be used alone or in combination of two or more kinds. For example, lignins may be used in combination with a condensation product of an aromatic compound having a sulfur-containing group with formaldehyde. As the aromatic compound, it is preferable to use bisphenols, biphenyls, naphthalene and the like.

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described for each main constituent element, but the present invention is not limited to the following embodiment.
(Negative electrode plate)
The negative electrode plate of the lead storage battery includes a negative electrode material. The negative electrode plate can usually be composed of a negative electrode current collector (negative electrode grid) and a negative electrode material. In addition, the negative electrode material is obtained by removing the negative electrode current collector from the negative electrode plate.
Members such as a mat and pasting paper may be attached to the negative electrode plate. When the negative electrode plate includes such a member (sticking member), the negative electrode material excludes the negative electrode current collector and the sticking member. However, the thickness of the electrode plate is a thickness including the mat. When the mat is attached to the separator, the thickness of the mat is included in the thickness of the separator.

  The negative electrode material contains a negative electrode active material (lead or lead sulfate) that exhibits a capacity by a redox reaction. The negative electrode active material in the charged state is spongy lead, but the unformed negative electrode plate is usually produced by using lead powder. The negative electrode material contains a carbon material. The negative electrode material may contain other additives such as an organic shrinkage inhibitor and barium sulfate, if necessary.

  The content of the organic anti-shrink agent contained in the negative electrode material is, for example, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, still more preferably 0.05% by mass or more. On the other hand, 1.0 mass% or less is preferable, 0.8 mass% or less is more preferable, and 0.5 mass% or less is further preferable. The lower limit value and the upper limit value can be arbitrarily combined. Here, the content of the organic anti-shrink agent contained in the negative electrode material is the content in the negative electrode material obtained by the method described below from the already-formed fully charged lead storage battery.

The content of barium sulfate in the negative electrode material is, for example, preferably 0.1 mass% or more, more preferably 0.2 mass% or more, 0.5 mass% or more, 1.0 mass% or more, It may be 1.3% by mass or more. On the other hand, 3.0 mass% or less is preferable, 2.5 mass% or less is more preferable, and 2 mass% or less is further preferable. The lower limit value and the upper limit value can be arbitrarily combined.

  Hereinafter, the organic shrinkproof agent contained in the negative electrode material and the method for quantifying barium sulfate will be described. Prior to quantitative analysis, the lead-acid battery after chemical formation should be fully charged and then disassembled to obtain the negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water and dried to remove the electrolytic solution in the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an uncrushed initial sample.

[Organic shrink proofing agent]
The uncrushed initial sample is crushed, and the crushed initial sample is immersed in a 1 mol/L NaOH aqueous solution to extract the organic shrinkage preventive agent. Insoluble components are removed by filtration from the extracted aqueous NaOH solution containing the organic shrinkage inhibitor. The obtained filtrate (hereinafter, also referred to as an analysis target filtrate) is desalted, then concentrated and dried to obtain a powder of an organic shrinkage inhibitor (hereinafter, also referred to as an analysis target powder). For desalting, the filtrate may be placed in a dialysis tube and immersed in distilled water.

  Infrared spectrum of the analysis target powder, UV-visible absorption spectrum of the solution obtained by dissolving the analysis target powder in distilled water, NMR spectrum of the solution obtained by dissolving the analysis target powder in a solvent such as heavy water, the substance By obtaining information from thermal decomposition GC-MS or the like, which can obtain information on individual constituent compounds, the organic anti-shrink agent is specified.

  The ultraviolet-visible absorption spectrum of the analysis target filtrate is measured. The content of the organic anti-shrink agent in the negative electrode material is quantified using the spectral intensity and the calibration curve prepared in advance. If it is not possible to strictly specify the structural formula of the organic shrinkage agent to be analyzed, and the calibration curve of the same organic shrinkage agent cannot be used, a UV-visible absorption spectrum similar to the organic shrinkage agent to be analyzed, an infrared spectrum, A calibration curve is prepared by using an organic shrinking agent that is available and shows an NMR spectrum and the like.

[Barium sulfate]
An unpulverized initial sample is pulverized, and 50 ml of (1+2) nitric acid is added to 10 g of the pulverized initial sample and heated for about 20 minutes to dissolve the lead component as lead nitrate. Next, the solution containing lead nitrate is filtered to separate solids such as carbonaceous material and barium sulfate.

  The obtained solid content is dispersed in water to obtain a dispersion liquid, and then components other than the carbonaceous material and barium sulfate (for example, a reinforcing material) are removed from the dispersion liquid by using a sieve. Next, the dispersion liquid is subjected to suction filtration using a membrane filter whose mass has been measured in advance, and the membrane filter is dried with a 110° C. drier together with the filtered sample. The sample filtered out is a mixed sample of carbonaceous material and barium sulfate. The mass (A) of the mixed sample is measured by subtracting the mass of the membrane filter from the total mass of the dried mixed sample and the membrane filter. Then, the dried mixed sample is put in a crucible together with a membrane filter, and is burnt at a temperature of 700° C. or higher. The remaining residue is barium oxide. The mass of barium oxide is converted into the mass of barium sulfate to obtain the mass (B) of barium sulfate.

  The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead or lead alloy sheet. Examples of the processing method include expanding processing and punching processing.

  The lead alloy used for the negative electrode current collector may be any of a Pb-Sb alloy, a Pb-Ca alloy, and a Pb-Ca-Sn alloy. These lead or lead alloy may further contain at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like as an additional element.

  The negative electrode plate can be formed by filling a negative electrode current collector with a negative electrode paste, aging and drying to produce an unformed negative electrode plate, and then forming an unformed negative electrode plate. The negative electrode paste is prepared by adding water and sulfuric acid to lead powder, a carbon material, and various additives as necessary, and kneading the mixture.

  When a reinforcing material is added, synthetic fiber or the like can be used. From the viewpoint of acid resistance and mechanical strength, fibers of polyolefin type, polyacrylic type, polyester type, and the like can be used, and shapes such as linear shape, curved shape, and curled shape can be used. It is preferable to use fibers having a fiber length of 0.5 to 20 mm. The fiber diameter is preferably 10 to 50 μm, more preferably 10 to 35 μm. It is preferable that the electrode material contains 0.01 to 2 mass%.

  The formation can be performed by charging the unformed negative electrode plate immersed in an electrolytic solution containing sulfuric acid. The formation may be performed in the battery case after the lead storage battery is assembled, or may be performed before the formation of the lead storage battery or the electrode plate group by separately preparing a formation tank containing the electrolytic solution.

(Positive plate)
There are a paste type and a clad type in the positive electrode plate of the lead storage battery.
The paste-type positive electrode plate includes a positive electrode current collector and a positive electrode material. The positive electrode material is held on the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and may be formed by casting lead or a lead alloy or processing a lead or lead alloy sheet.

  The clad-type positive electrode plate is composed of a plurality of porous tubes, a core metal inserted into each tube, a current collector that connects the core metals, and a positive electrode material filled in the tube into which the core metal is inserted. And a connecting seat that connects a plurality of tubes. The cored bar and the current collector that connects the cored bar are collectively referred to as a positive electrode current collector.

  Examples of the lead alloy used for the positive electrode current collector include Pb-Ca-based alloys, Pb-Sb-based alloys, Pb-Ca-Sn-based alloys, and the like. The lead alloy may further contain, as an additional element, at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, and Cu. The positive electrode current collector may have lead alloy layers having different compositions, and may have a plurality of alloy layers. For the core metal, a Pb-Ca-based alloy, a Pb-Sb-based alloy, or the like is used.

  The positive electrode material contains a positive electrode active material (lead dioxide, lead sulfate, lead monoxide) that exhibits a capacity by a redox reaction. The positive electrode material may contain other additives as needed.

  The unformed paste-type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste prepared by adding lead powder, various additives, water, and sulfuric acid, aging, and drying. At the time of aging, it is preferable to age the unformed positive electrode plate at a temperature higher than room temperature and a high humidity. Then, an unformed positive electrode plate is formed.

  The clad-type positive electrode plate is formed by filling a tube in which a core metal is inserted with lead powder or slurry-like lead powder, and connecting a plurality of tubes with a seat.

(Separator)
A separator is usually arranged between the negative electrode plate and the positive electrode plate.
A microporous film can be used for the separator. The microporous membrane is a porous sheet mainly containing a fiber component, and for example, a composition containing a pore-forming agent (polymer powder and/or oil, etc.) is extruded into a sheet shape, and then the pore-forming agent is added. It is obtained by removing and forming pores. The microporous membrane is preferably composed of a material having acid resistance, and is preferably composed mainly of a polymer component. As the polymer component, polyolefins such as polyethylene and polypropylene are preferable.

The electric resistance of the separator (microporous film) is, for example, 0.0015 Ω·dm ² /sheet or more, and preferably 0.0015 to 0.0035 Ω·dm ² /sheet, for example.

  The separator may be composed of one microporous film, or may be composed of a plurality of microporous films stacked together. The thickness (total thickness) of the separator (microporous film) is, for example, 0.2 to 1.5 mm. The average pore diameter of the microporous membrane is, for example, 30 μm or less.

(Electrolyte)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The specific gravity at 20° C. of the electrolytic solution in the lead storage battery in a fully charged state after formation is, for example, 1.10 to 1.35 g/cm ³ , and preferably 1.20 to 1.35 g/cm ³ .

FIG. 1 shows an external appearance of an example of a lead storage battery according to an embodiment of the present invention.
The lead-acid battery 1 includes a battery case 12 that contains an electrode plate group 11 and an electrolytic solution (not shown). The inside of the battery case 12 is partitioned into a plurality of cell chambers 14 by partition walls 13. One electrode plate group 11 is housed in each cell chamber 14. The opening of the battery case 12 is sealed with a lid 15 having a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a liquid port plug 18 for each cell chamber. When replenishing water, the liquid port plug 18 is removed to replenish the replenishing water. The liquid port plug 18 may have a function of discharging the gas generated in the cell chamber 14 to the outside of the battery.

  The electrode plate group 11 is configured by laminating a plurality of negative electrode plates 2 and a plurality of positive electrode plates 3 with a separator 4 in between. Here, the bag-shaped separator 4 that accommodates the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. Further, a porous layer (not shown) is arranged between the negative electrode plate 2 or the positive electrode plate 3 and the separator 4. In the cell chamber 14 located at one end of the battery case 12, the negative electrode shelf 6 that connects the ears 2 a of the plurality of negative electrode plates 2 in parallel is connected to the through-connecting body 8, and the ears of the plurality of positive electrode plates 3 are connected. A positive pole shelf 5 that connects 3 a in parallel is connected to a positive pole 7. The positive pole 7 is connected to a positive terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative pole 9 is connected to the negative shelf 6 and the through-connector 8 is connected to the positive shelf 5. The negative pole 9 is connected to a negative terminal 16 outside the lid 15. Each through connection body 8 passes through a through hole provided in the partition wall 13 and connects the electrode plate groups 11 of the adjacent cell chambers 14 in series.

The lead-acid batteries according to one aspect of the present invention are collectively described below.
(1) One aspect of the present invention is a lead acid battery,
The lead acid battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution,
The negative electrode plate includes a negative electrode material containing a carbon material,
The carbon material includes a first carbon material having a particle diameter of 32 μm or more and a second carbon material having a particle diameter of less than 32 μm,
A ratio of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material: R2/R1 is 15 or more and 155 or less,
It is a lead storage battery in which a porous layer is arranged between the negative electrode plate and the positive electrode plate.

  (2) In the above (1), the ratio of the specific surface area S2 of the second carbon material to the specific surface area S1 of the first carbon material: S2/S1 is preferably 20 or more.

  (3) In the above (1) or (2), the ratio of the specific surface area S2 of the second carbon material to the specific surface area S1 of the first carbon material: S2/S1 is preferably 240 or less.

  (4) In any one of the above (1) to (3), the average aspect ratio of the first carbon material is preferably 1.5 or more.

  (5) In any one of the above (1) to (4), the average aspect ratio of the first carbon material is preferably 30 or less.

(6) In any one of the above (1) to (5), the thickness of the porous layer is preferably 10 μm or more.
(7) In any one of the above (1) to (6), the thickness of the porous layer is preferably 500 μm or less.

(8) In any one of the above (1) to (7), the content of the first carbon material in the negative electrode material is preferably 0.05% by mass or more.
(9) In any one of the above (1) to (8), the content of the first carbon material in the negative electrode material is preferably 3.0% by mass or less.
(10) In any one of the above (1) to (9), the content of the second carbon material in the negative electrode material is preferably 0.03 mass% or more.
(11) In any one of the above (1) to (10), the content of the second carbon material in the negative electrode material is preferably 1.0% by mass or less.
(12) In any one of the above (1) to (11), it is preferable that the first carbon material contains at least graphite and the second carbon material contains at least carbon black.

  Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

<<Lead storage battery A1>>
(1) Preparation of Negative Electrode Plate Lead powder, water, sulfuric acid, barium sulfate, a carbon material, an organic shrink proofing agent, and a reinforcing material are mixed to obtain a negative electrode paste. The negative electrode paste is filled into the mesh portion of the expanded lattice made of Pb-Ca-Sn alloy, aged and dried to obtain an unformed negative electrode plate. Carbon black (average particle diameter D ₅₀ : 40 nm) and graphite (average particle diameter D ₅₀ : 110 μm) are used as the carbon material.

  The amount of the organic anti-shrinking agent added to the negative electrode paste is adjusted so that the amount of the organic anti-shrinking agent contained in 100% by mass of the negative electrode material after full formation in the already formed chemical composition is 0.2% by mass. As the organic anti-shrink agent, sodium lignin sulfonate is used. The amount of barium sulfate added to the negative electrode paste is adjusted so that the amount of barium sulfate contained in 100% by mass of the negative electrode material after full formation in the already formed composition is 0.8% by mass. The amount of the reinforcing material to be added to the negative electrode paste is adjusted so that the amount of the reinforcing material contained in 100% by mass of the negative electrode material after fully formed and fully charged is 0.1% by mass. Synthetic fibers are used as the reinforcing material.

(2) Production of Positive Electrode Plate Lead powder, water, sulfuric acid, and a reinforcing material are mixed to obtain a positive electrode paste. The positive electrode paste is filled in the mesh portion of the expanded lattice made of Pb-Ca-Sn alloy, aged and dried to obtain an unformed positive electrode plate. The amount of the reinforcing material to be added to the positive electrode paste is adjusted so that the amount of the reinforcing material contained in 100% by mass of the positive electrode material after full formation in the existing formation is 0.1% by mass. Synthetic fibers are used as the reinforcing material.

(3) Production of lead-acid battery Porous layers are arranged on both surfaces of the unformed negative electrode plate. More specifically, a non-woven fabric made of glass fiber (fiber diameter 16 μm, density 0.16 g/cm ³ , thickness 400 μm, electric resistance 0.0010 Ω·dm ² ) was used for the porous layer, and 1 was used on each side of the negative electrode plate. Overlap one by one.
An unformed negative electrode plate with a porous layer on both sides is housed in a bag-shaped separator made of a polyethylene microporous film (average pore diameter 25 μm, thickness 0.25 mm, electric resistance 0.0025 Ω·dm ² ). Then, an electrode plate group is formed by 7 unformed negative electrode plates and 6 unformed positive electrode plates per cell.

  The group of 6 plates is inserted into a polypropylene battery case, connected in series, and a lid is attached to the opening of the battery case. The electrolyte is injected from the injection port provided in the lid, a liquid port plug is attached to the injection port, and chemical formation is performed in the battery case. In this way, the liquid lead storage battery A1 is manufactured. The nominal voltage of the lead storage battery is 12V. The nominal capacity of the lead storage battery is 28 Ah (5-hour rate). The specific gravity of the electrolytic solution injected into the battery case is adjusted so that the specific gravity of the electrolytic solution after formation is 1.285.

In the present lead acid battery, the content of the first carbon material is 1.0% by mass and the content of the second carbon material is 0.3% by mass. However, these values are obtained when the negative electrode plate of the manufactured lead storage battery is taken out and the carbon material contained in the negative electrode material is separated into the first carbon material and the second carbon material by the procedure described above. It is a value obtained as the content of each carbon material contained in the electrode material (100% by mass).
The powder resistance ratio R2/R1 is 155. The powder resistance ratio R2/R1 is obtained from the lead storage battery manufactured by the procedure described above. Further, the specific surface area ratio S2/S1 obtained by the procedure described above is 112. The average aspect ratio of the first carbon material obtained by the procedure described above is 16. The thickness of the porous layer (nonwoven fabric made of glass fiber) obtained by the procedure described above is 400 μm.

The following evaluation is performed on the lead storage battery manufactured above.
[Evaluation 1: PSOC life test]
A PSOC life test is conducted under the conditions shown in Table 1 in a 40° C. air tank. The number of cycles until the terminal voltage reaches 1.2 V per unit cell is used as an index of PSOC life performance. It is expressed as a ratio when the result of the lead storage battery X2 described below is 100. When the PSOC life performance is 115 or more, it is evaluated that the PSOC life performance is improved.

[Evaluation 2: Penetration short circuit acceleration test]
An osmotic short circuit promotion test is performed under the conditions shown in Table 2 in a water tank at 25°C. After the test, disassemble the lead acid battery and inspect for short circuits. Specifically, a test is performed on 20 lead storage batteries, and the proportion of lead storage batteries in which a short circuit has occurred is checked among the 20 lead storage batteries. When the occurrence rate of osmotic short circuit is 25% or less, it is evaluated that the osmotic short circuit is suppressed. In addition, this test is a test performed under a condition where an osmotic short circuit easily occurs, and the osmotic short circuit occurrence rate obtained under the test condition is significantly higher than that under the actual use condition of the lead storage battery. The resistance left in Table 2 means that the lead storage battery is left with a resistance of 10Ω connected between the terminals.

[Evaluation 3: Charge acceptability test]
A charge acceptability test is performed under the conditions shown in Table 3 in a water tank at 25°C or in a gas tank at 0°C. The current value at the time when 10 minutes of CV charging in step 3 in Table 3 has elapsed is used as an index of the charge acceptance performance. It is expressed as a ratio when the result of the lead storage battery X2 described below is 100.

<<Lead storage batteries A2-A7>>
The powder resistance ratio R2/R1 is set to the value shown in Table 4 by adjusting the average particle diameter D ₅₀ of each carbon material used, the specific surface area, and the average aspect ratio of the first carbon material. The specific surface area ratio S2/S1 determined by the procedure described above is within the range of 20 to 240. The average aspect ratio of the first carbon material obtained by the procedure described above is within the range of 1.5 to 30. Lead storage batteries A2 to A7 are prepared and evaluated in the same manner as the lead storage battery A1 except for the above.

<<Lead storage battery X1>>
A lead storage battery X1 was produced in the same manner as the lead storage battery A1 except that only carbon black (average particle diameter D ₅₀ : 40 nm) was used as the carbon material and the content of the second carbon material was 0.3 mass %. And evaluate.

<<Lead storage batteries B1 to B5>>
The average particle diameter D ₅₀ of each carbon material _used, by adjusting the specific surface area and an average aspect ratio of the first carbon material, the powder resistance ratio R2 / R1 and the values shown in Table 2. No porous layer is arranged on both sides of the negative electrode plate. The specific surface area ratio S2/S1 determined by the procedure described above is within the range of 20 to 240. The average aspect ratio of the first carbon material obtained by the procedure described above is within the range of 1.5 to 30. Lead storage batteries B1 to B5 are prepared and evaluated in the same manner as the lead storage battery A1 except for the above.

<<Lead storage battery X2>>
Only carbon black (average particle diameter D ₅₀ : 40 nm) is used as the carbon material, and the content of the second carbon material is 0.3 mass %. No porous layer is arranged on both sides of the negative electrode plate. A lead storage battery X2 is prepared and evaluated in the same manner as the lead storage battery A1 except for the above.
Table 4 shows the evaluation results of the lead storage batteries A1 to A7, B1 to B5, and X1 to X2.

  In the lead storage batteries B2 and B3 in which the first carbon material and the second carbon material are used as the carbon material and the powder resistance ratio R2/R1 is 15 to 155, the lead storage batteries X2 using only carbon black as the carbon material are compared. , PSOC life performance is improved, but permeation short circuit is likely to occur. In the lead storage batteries B1, B4, B5, the improvement in PSOC life performance is insufficient.

In the lead storage batteries A1 to A3 in which the first carbon material and the second carbon material are used as the carbon material and the powder resistance ratio R2/R1 is 15 to 155, the permeation short circuit is suppressed by disposing the porous layer. ..
In the lead storage batteries A1 to A3 in which the first carbon material and the second carbon material are used as the carbon material and the powder resistance ratio R2/R1 is 15 to 155, even if the porous layer is arranged, high PSOC life performance is improved. The effect is obtained. Further, in the lead storage batteries A1 to A3, the charge acceptance performance is also improved.

When the lead storage batteries X1 and X2 using only carbon black as the carbon material are compared, the reduction rate of the PSOC life performance due to the arrangement of the porous layer of the lead storage battery X1 with respect to the lead storage battery X2 is 10%. The rate of decrease in the PSOC life performance is calculated by the following formula.
Reduction rate of PSOC life performance (%)=(N _X2 −N _X1 )/N _X2 ×100
N _X1 and N _X2 in the above equation are the PSOC life performance of the lead storage batteries X1 and X2, respectively.

On the other hand, when the lead storage batteries A1 and B2 in which the first carbon material and the second carbon material are used as the carbon material and the powder resistance ratio R2/R1 is 155 are compared, the lead storage battery A1 is porous relative to the lead storage battery B2. The reduction rate of the PSOC life performance due to the arrangement of the layers is reduced to about 3.8%.
When the lead storage batteries A2 and B3 using the first carbon material and the second carbon material as the carbon material and the powder resistance ratio R2/R1 of 83 are compared, the PSOC due to the arrangement of the porous layer of the lead storage battery A2 with respect to the lead storage battery B3. The reduction rate of the life performance is reduced to about 3.6%. As described above, when the first carbon material and the second carbon material are used as the carbon material and the powder resistance ratio R2/R1 is set to 15 to 155, the porous material is more porous than the case where only the carbon black is used as the carbon material. Degradation of PSOC life performance due to layer placement is suppressed.

<<Lead storage batteries C1 to C6>>
By adjusting the specific surface area of each carbon material to be used, the specific surface area ratio S2/S1 obtained by the procedure described above is set to the value shown in Table 5. The powder resistance ratio R2/R1 obtained by the procedure described above is set to 15 to 155. The average aspect ratio of the first carbon material obtained by the procedure described above is 1.5 to 30. The lead storage batteries C1 to C6 are manufactured and evaluated in the same manner as the lead storage battery A1 except for the above.

<<Lead storage batteries D1 to D5>>
By adjusting the specific surface area of each carbon material to be used, the specific surface area ratio S2/S1 obtained by the procedure described above is set to the value shown in Table 5. No porous layer is arranged on both sides of the negative electrode plate. The powder resistance ratio R2/R1 obtained by the procedure described above is set to 15 to 155. The average aspect ratio of the first carbon material obtained by the procedure described above is 1.5 to 30. Lead storage batteries D1 to D5 are prepared and evaluated in the same manner as the lead storage battery A1 except for the above.
Table 5 shows the evaluation results of the lead storage batteries C1 to C6 and D1 to D5.

In the lead storage batteries D1 to D5 in which R2/R1 is in the range of 15 to 155 and the porous layer is not arranged, the penetration short circuit occurrence rate is as high as 30% or more.
In the lead storage batteries C1 to C6 in which R2/R1 is in the range of 15 to 155 and the porous layer is arranged, the PSOC life performance is 115 or higher and the penetration short circuit occurrence rate is 25% or lower. In the lead storage batteries C1 to C4 having the specific surface area ratio S2/S1 of 20 or more, high charge acceptance performance can be obtained even when the porous layer is arranged. Among them, in the lead storage batteries C2 to C4 having the specific surface area ratio S2/S1 of 20 or more and 240 or less, the property of the negative electrode paste used for producing the negative electrode plate is good, and the filling property of the negative electrode paste into the negative electrode current collector is improved. To do. Therefore, the negative electrode material is in good contact with the negative electrode current collector, and the conduction between the negative electrode material and the negative electrode current collector is good. Therefore, high PSOC life performance and charge acceptance performance can be obtained in good balance.

<<Lead storage batteries E1 to E5>>
By adjusting the average aspect ratio of the carbon material used, the average aspect ratio of the first carbon material obtained by the procedure described above is set to the value shown in Table 6. The powder resistance ratio R2/R1 obtained by the procedure described above is set to 15 to 155. The specific surface area ratio S2/S1 determined by the procedure described above is 20 to 240. Lead storage batteries E1 to E5 are prepared and evaluated in the same manner as the lead storage battery A1 except for the above.

<<Lead storage batteries F1 to F4>>
By adjusting the average aspect ratio of the carbon material to be used, the average aspect ratio obtained by the procedure described above is set to the value shown in Table 6. No porous layer is arranged on both sides of the negative electrode plate. The powder resistance ratio R2/R1 obtained by the procedure described above is set to 15 to 155. The specific surface area ratio S2/S1 determined by the procedure described above is 20 to 240. Lead storage batteries F1 to F4 are prepared and evaluated in the same manner as the lead storage battery A1 except for the above.
Table 6 shows the evaluation results of the lead storage batteries E1 to E5 and F1 to F4.

In the lead storage batteries F1 to F4 in which R2/R1 is in the range of 15 to 155 and the porous layer is not arranged, the penetration short circuit occurrence rate is as high as 30% or more.
In the lead storage batteries E1 to E5 in which R2/R1 is in the range of 15 to 155 and the porous layer is arranged, the PSOC life performance is 115 or higher and the penetration short circuit occurrence rate is 25% or lower. In particular, in the lead storage batteries E2 to E4 in which the aspect ratio of the first carbon material is 1.5 to 30, high PSOC life performance is obtained, and the penetration short circuit occurrence rate is significantly reduced to 15% or less.

<<Lead storage batteries G1 to G5>>
By adjusting the thickness of the non-woven fabric used for the porous layer, the thickness of the porous layer obtained by the procedure described above is set to the value shown in Table 7. The powder resistance ratio R2/R1 obtained by the above-described procedure is set to 15. The specific surface area ratio S2/S1 obtained by the procedure described above is 112. The average aspect ratio of the first carbon material obtained by the procedure described above is 16. The lead storage batteries G1 to G5 are manufactured and evaluated in the same manner as the lead storage battery A1 except for the above.

<<Lead storage battery X3>>
No porous layer is arranged on both sides of the negative electrode plate. The powder resistance ratio R2/R1 obtained by the above-described procedure is set to 15. The specific surface area ratio S2/S1 obtained by the procedure described above is 112. The average aspect ratio of the first carbon material obtained by the procedure described above is 16. A lead storage battery X3 is prepared and evaluated in the same manner as the lead storage battery A1 except for the above.
Table 7 shows the evaluation results of the lead storage batteries G1 to G5 and X3.

  In the lead storage batteries G1 to G5 in which R2/R1 is in the range of 15 to 155 and the porous layer is arranged, the PSOC life performance is 115 or higher and the penetration short circuit occurrence rate is 25% or lower. In particular, in the lead storage batteries G2 to G4 in which the thickness of the porous layer is 10 to 500 μm, the penetration short circuit occurrence rate is significantly reduced, and the decrease in charge acceptance performance is suppressed.

  INDUSTRIAL APPLICABILITY The lead storage battery according to one aspect of the present invention can be applied to control valve type and liquid type lead storage batteries, and is suitable as a power source for starting an automobile or a motorcycle, or as an industrial power storage device for storing natural energy. Available for

DESCRIPTION OF SYMBOLS 1 Lead acid battery 2 Negative electrode plate 2a Negative electrode plate ears 3 Positive electrode plate 3a Positive electrode plate ears 4 Separator 5 Positive electrode shelf 6 Negative shelf 7 Positive pole 8 Through plug 9 Negative pole 11 Pole plate group 12 Battery case 13 Partition wall 14 Cell chamber 15 Lid 16 Negative electrode terminal 17 Positive electrode terminal 18 Liquid stopper

Claims (12)

A lead acid battery,
The lead acid battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution,
The negative electrode plate includes a negative electrode material containing a carbon material,
The carbon material includes a first carbon material having a particle diameter of 32 μm or more and a second carbon material having a particle diameter of less than 32 μm,
A ratio of the powder resistance R2 of the second carbon material to the powder resistance R1 of the first carbon material: R2/R1 is 15 or more and 155 or less,
A lead storage battery in which a porous layer is disposed between the negative electrode plate and the positive electrode plate.   The lead storage battery according to claim 1, wherein a ratio S2/S1 of the specific surface area S2 of the second carbon material to the specific surface area S1 of the first carbon material is 20 or more.   The lead acid battery according to claim 1 or 2, wherein a ratio of the specific surface area S2 of the second carbon material to the specific surface area S1 of the first carbon material: S2/S1 is 240 or less.   The lead acid battery according to any one of claims 1 to 3, wherein an average aspect ratio of the first carbon material is 1.5 or more.   The lead acid battery according to any one of claims 1 to 4, wherein an average aspect ratio of the first carbon material is 30 or less.   The lead acid battery according to claim 1, wherein the thickness of the porous layer is 10 μm or more.   The lead storage battery according to claim 1, wherein the porous layer has a thickness of 500 μm or less.   The lead acid battery according to any one of claims 1 to 7, wherein a content of the first carbon material in the negative electrode material is 0.05% by mass or more.   The lead storage battery according to any one of claims 1 to 8, wherein a content of the first carbon material in the negative electrode material is 3.0% by mass or less.   The lead acid battery according to any one of claims 1 to 9, wherein a content of the second carbon material in the negative electrode material is 0.03 mass% or more.   The lead acid battery according to any one of claims 1 to 10, wherein a content of the second carbon material in the negative electrode material is 1.0% by mass or less.   The lead acid battery according to claim 1, wherein the first carbon material contains at least graphite, and the second carbon material contains at least carbon black.

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