lead-acid battery

Abstract

DEPCT63 A lead-acid battery consists of a negative electrode plate and a positive electrode plate; the negative electrode plate... It consists of a negative electrode and negative electrode material combined with carbon material. This carbon consists of first-carbon material with a particle size greater than or equal to 32. Micrometer and second carbon material with particle size less than 32 micrometers, ratio of powder. The resistance R2 of the second carbon material is connected to the resistance R1 of the first carbon material: R2 / R1. Greater than or equal to 15, less than or equal to 155, the negative terminal of the electrolytic capacitor. Contains a Pb alloy incorporating more than 0.06% Ca by mass less than or equal to... 0.15% by mass and Sn greater than or equal to 0.10% by mass less than or equal to 0.80% by mass. mass The image chosen is image 1. -----------------------------------------------------------

Description

lead acid battery

[0001] The present invention relates to a lead-acid battery.

[0002] Lead-acid batteries are used in a variety of applications, including automotive and industrial applications. A lead-acid battery includes a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate includes a current collector (such as a grid-shaped current collector) and a negative electrode material. Lead or a lead alloy is used for the current collector. The negative electrode material includes a negative electrode active material, a carbon material, and the like.

[0003] Patent Document 1 proposes the use of a negative electrode current collector made of a Pb—Ca—Sn alloy in a valve-regulated lead-acid battery. Patent Document 2 proposes the use of a negative electrode grid made of a Pb—Ca—Sn alloy that is substantially free of Sb in a lead-acid battery. Patent Document 2 also describes the addition of acetylene black and expanded graphite to the negative electrode active material.

[0004] JP 2016-177909 A JP 2010-277941 A

[0005] In lead-acid batteries, the end of the negative electrode current collector is formed with a lug for collecting current from the negative electrode plate and connecting it to the battery's external terminal. In lead-acid batteries for idle-stop systems, the negative electrode lug can corrode and break during charging and discharging. This is thought to be because the lead contained in the negative electrode lug is oxidized during discharging during the charge-discharge cycle but is not completely reduced to lead during charging. This repetition gradually causes corrosion inside the lug. Even in flooded lead-acid batteries and valve-regulated lead-acid batteries, corrosion can occur when the lug reaches a specific potential.

[0006] One aspect of the present invention relates to a lead-acid battery comprising: a negative electrode plate; and a positive electrode plate; the negative electrode plate comprises a negative electrode current collector and 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 powder resistance R2 of the second carbon material to powder resistance R1 of the first carbon material: R2 / R1 is 15 or more and 155 or less; and the negative electrode current collector is made of a Pb alloy containing more than 0.06 mass % and 0.15 mass % or less of Ca and 0.10 mass % or more and 0.80 mass % or less of Sn.

[0007] According to the above aspect of the present invention, corrosion of the lug portion of the negative electrode plate in a lead-acid battery can be suppressed.

[0008] 1 is a partially cutaway exploded perspective view showing the appearance and internal structure of a lead-acid battery according to an embodiment of the present invention.

[0009] A lead-acid battery according to one aspect of the present invention includes a negative electrode plate and a positive electrode plate. The negative electrode plate includes a negative electrode current collector and 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. 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 negative electrode current collector is made of a Pb alloy containing more than 0.06 mass% but not more than 0.15 mass% Ca and 0.10 mass% or more and not more than 0.80 mass% Sn.

[0010] The ear of the negative electrode plate is made of Pb and PbSO ４ It is known that repeated exposure to specific potentials near the equilibrium potential with the negative electrode (specifically, a potential near +40 mV during discharge and a potential near −80 mV during charge) accelerates corrosion of the lug. Conventionally, attempts have been made to suppress the corrosion of the lug by changing the alloy composition of the negative electrode current collector.

[0011] The inventors discovered that the potential of the lug of a negative electrode plate is affected by the composition of the negative electrode material. For example, when the carbon material contained in the negative electrode material is carbon black, the potential of the lug of the negative electrode plate is likely to fall within the specific potential range where corrosion is likely to occur. Furthermore, they found that when carbon black is used as the carbon material, changing the alloy composition of the negative electrode current collector does not significantly suppress the corrosion of the lug. Through trial and error, the inventors discovered that by using two types of carbon materials (a first carbon material and a second carbon material) with different particle sizes as the negative electrode carbon material and adjusting the powder resistance ratio R2 / R1 of these carbon materials, the corrosion suppression effect achieved by controlling the alloy composition of the negative electrode current collector can be more easily achieved, and corrosion of the lug of the negative electrode plate can be significantly suppressed.

[0012] In the above aspect of the present invention, the negative electrode material includes a first carbon material and a second carbon material having a powder resistivity ratio R2 / R1 of 15 or more and 155 or less, and the negative electrode current collector is formed of a Pb alloy containing more than 0.06 mass% to 0.15 mass% Ca and 0.10 mass% to 0.80 mass% Sn. This configuration significantly suppresses corrosion of the negative electrode plate lug. While the details of the mechanism by which lug corrosion is suppressed are unknown, it is presumed that setting the powder resistivity ratio R2 / R1 of the carbon material in the negative electrode material within the above range changes the polarization characteristics of the negative electrode plate, thereby shifting the potential of the lug during charge and discharge away from the specific potential at which corrosion progresses, thereby reducing corrosion of the negative electrode lug. Furthermore, when the powder resistivity ratio R2 / R1 is within the above range, it is possible to suppress the accumulation of lead sulfate and achieve high low-temperature high-rate performance. This is thought to be because a conductive network is easily formed in the negative electrode material and corrosion of the lug is suppressed, maintaining a secure conductive path in the lug and improving conductivity throughout the negative plate.The reason for the reduction in lead sulfate accumulation is thought to be because the improved conductivity throughout the negative plate makes it easier for the reduction reaction of lead sulfate to proceed.

[0013] Carbon materials are generally known to have various powder resistances. It is known that the powder resistance of a powder material varies depending on the particle shape, particle diameter, internal structure, and / or crystallinity of the particles. Conventional common knowledge does not consider that the powder resistance of a carbon material affects corrosion of the lug of a negative electrode plate.

[0014] 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 and 240 or less. When the specific surface area ratio S2 / S1 is in this range, high low-temperature high-rate performance can be ensured. Negative electrode materials usually contain an organic shrinkage inhibitor, and when the specific surface area ratio S2 / S1 is in the above range, adsorption of the organic shrinkage inhibitor to the carbon material is suppressed, thereby exhibiting a shrinkage-preventing effect, which is thought to improve low-temperature high-rate performance.

[0015] The average aspect ratio of the first carbon material is preferably 1.5 or more and 30 or less. In this case, a conductive network is easily formed in the negative electrode material, thereby obtaining high low-temperature high-rate performance. Furthermore, the formation of many conductive networks facilitates the progress of the reduction reaction of lead sulfate, thereby reducing the accumulation of lead sulfate.

[0016] The content of the first carbon material in the negative electrode material is 0.03% by mass or more and 3.0% by mass or less, and more preferably 2.5% by mass or less. The content of the second carbon material is 0.03% by mass or more and 1.5% by mass or less, and preferably 0.05% by mass or more. In this case, a conductive network is easily formed in the negative electrode material while suppressing corrosion of the edge portions, thereby improving low-temperature high-rate performance and reducing the accumulation of lead sulfate.

[0017] Lead-acid batteries according to embodiments of the present invention will be described below by their main components, but the present invention is not limited to the following embodiments. (Negative Electrode Plate) The negative electrode plate of a lead-acid battery includes a negative electrode material and a negative current collector. The negative electrode material is the negative electrode plate excluding the negative current collector. The negative electrode plate may have a mat, pasting paper, or other member attached thereto. When the negative electrode plate includes such a member (attaching member), the negative electrode material is the negative electrode material excluding the negative current collector and the attaching member. However, the thickness of the electrode plate includes the thickness of the mat. When a mat is attached to the separator, the thickness of the mat is included in the thickness of the separator.

[0018] The negative electrode material contains a negative electrode active material (lead or lead sulfate) that develops capacity through an oxidation-reduction reaction. The negative electrode active material in a charged state is spongy metallic lead, but unformed negative electrodes are usually made using lead powder. The negative electrode material also contains a carbon material. The negative electrode material may further contain an organic shrinkage inhibitor, barium sulfate, etc., and may also contain other additives as needed.

[0019] (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. The first carbon material and the second carbon material are separated and distinguished by the procedure described below.

[0020] Examples of the carbon materials include carbon black, graphite, hard carbon, soft carbon, etc. Examples of carbon black include acetylene black, ketjen black, furnace black, lamp black, etc. The graphite may be any carbon material containing a graphite-type crystal structure, and may be either artificial graphite or natural graphite.

[0021] In addition, among the first carbon materials, the Raman spectrum of 1300 cm －１ 1350cm or more －１ The peaks appearing in the following range (D band) and 1550 cm －１ More than 1600cm －１ Intensity ratio I to the peak (G band) appearing in the following range Ｄ / IＧ A carbon material having a value of 0 or more and 0.9 or less is called graphite.

[0022] The type, specific surface area, and / or aspect ratio of the carbon material used to prepare the negative electrode material may be selected or adjusted so that 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. In addition to these factors, the particle size of the carbon material used may also be adjusted. By selecting or adjusting these factors, the powder resistance of each of the first carbon material and the second carbon material can be adjusted, and as a result, the powder resistance ratio R2 / R1 can be adjusted.

[0023] The first carbon material is preferably at least one selected from the group consisting of graphite, hard carbon, and soft carbon. In particular, the first carbon material preferably contains at least graphite. The second carbon material preferably contains at least carbon black. Use of these carbon materials makes it easy to adjust the powder resistance ratio R2 / R1.

[0024] The powder resistance ratio R2 / R1 may be 15 or more and 155 or less, and may be 15 or more and 152 or less. In a lead-acid battery according to one aspect of the present invention, when the powder resistance ratio of the first carbon material and the second carbon material in the negative electrode material is within this range, corrosion of the lug of the negative electrode plate can be suppressed. This is thought to be because, by setting the powder resistance ratio R2 / R1 within the above range, the polarization characteristics of the negative electrode plate change, and the potential of the lug during charge and discharge falls outside the potential range in which corrosion progresses. Furthermore, when the powder resistance ratio is within the above range, accumulation of lead sulfate can be suppressed and high low-temperature high-rate performance can be achieved. This is thought to be because, by setting the powder resistance ratio R2 / R1 within the above range, a conductive network can be easily formed in the negative electrode material. On the other hand, even when the negative electrode current collector is made of a Pb alloy having the above-mentioned composition, unlike the present invention, when the powder resistance ratio R2 / R1 is less than 15 or exceeds 155, almost no corrosion suppression effect of the lug of the negative electrode plate is obtained. Furthermore, if the powder resistance ratio R2 / R1 is less than 15 or exceeds 155, it is difficult to obtain the effect of reducing the amount of lead sulfate accumulation and / or the effect of improving low-temperature high-rate performance.

[0025] In a lead-acid battery according to one aspect of the present invention, 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 500 or less, and preferably 20 or more. It is also preferably 400 or less, and more preferably 240 or less. These upper and lower limits can be arbitrarily combined. From the viewpoint of easily exerting the shrinkage-preventing effect of the organic shrinkage preventer and obtaining high low-temperature high-rate performance, the specific surface area ratio S2 / S1 is preferably 20 or more and 240 or less. Even when the specific surface area ratio S2 / S1 is within this range, high corrosion resistance of the edge portion of the negative electrode plate is ensured.

[0026] The average aspect ratio of the first carbon material is, for example, 1 or more and 100 or less, and preferably 1.5 or more. It is preferably 35 or less, and more preferably 30 or less. These upper and lower limits can be combined arbitrarily. When the average aspect ratio of the first carbon material is 1.5 or more and 30 or less, a conductive network is more easily formed in the negative electrode material, and lead sulfate is more easily reduced, thereby improving low-temperature high-rate performance and reducing the accumulation of lead sulfate. Furthermore, from the viewpoint of high dispersibility of the first carbon material in the negative electrode material, the average aspect ratio of the first carbon material is preferably 1 or more and 35 or less, or 1.5 or more and 30 or less.

[0027] The total content of the first carbon material and the second carbon material in the negative electrode material is, for example, 0.1 mass% or more and 3.5 mass% or less, preferably 0.3 mass% or more and more preferably 0.5 mass% or more. It is also preferably 2.5 mass% or less and more preferably 2 mass% or less. These upper and lower limits can be arbitrarily combined. When the total content of the first carbon material and the second carbon material is within this range, a conductive network is easily formed, further enhancing the effect of improving low-temperature rate performance.

[0028] The content of the first carbon material in the negative electrode material is, for example, 0.03 mass% or more and 3.0 mass% or less, preferably 2.5 mass% or less, and more preferably 2.0 mass% or less. It is also preferably 0.05 mass% or more, and more preferably 0.1 mass% or more. These upper and lower limits can be combined arbitrarily. When the content of the first carbon material is within this range, a conductive network is easily formed in the negative electrode material, thereby improving low-temperature high-rate performance and reducing lead sulfate accumulation.

[0029] The content of the second carbon material in the negative electrode material is, for example, 0.03% by mass or more and 1.5% by mass or less, preferably 0.05% by mass or more, and more preferably 0.1% by mass or more. It is also preferably 1.0% by mass or less, and more preferably 0.7% by mass or less. These upper and lower limits can be arbitrarily combined. When the content of the second carbon material is 0.05% by mass or more, a conductive network is easily formed in the negative electrode material. When the content of the second carbon material is 1.5% by mass or less, the effect of controlling the alloy composition of the negative electrode current collector is easily achieved, and the corrosion suppression effect of the lug portion can be further enhanced.

[0030] The methods for determining or analyzing the physical properties of carbon materials are described below. (A) Analysis of Carbon Materials (A-1) Separation of Carbon Materials: A fully charged lead-acid battery prepared using chemical synthesis was disassembled, the negative electrode plate was removed, washed with water to remove sulfuric acid, and vacuum dried (dried under a pressure lower than atmospheric pressure). Next, the negative electrode material was collected from the dried negative electrode plate and pulverized. 30 mL of a 60% by weight aqueous nitric acid solution was added to 5 g of the pulverized sample and heated to 70°C. 10 g of disodium ethylenediaminetetraacetate, 30 mL of a 28% by weight aqueous ammonia, and 100 mL of water were added to this mixture, and heating was continued to dissolve the soluble components. The pretreated sample was then recovered by filtration. The recovered sample was passed through a 500 μm sieve to remove large components such as reinforcing materials, and the components that passed through the sieve were recovered as carbon material.

[0031] When the recovered carbon material is wet sieved using a sieve with 32 μm openings, the material that does not pass through the sieve and remains on the sieve is called the first carbon material, and the material that passes through the sieve is called the second carbon material. In other words, the particle size of each carbon material is based on the size of the sieve openings. For wet sieving, JIS Z8815:1994 can be referenced.

[0032] Specifically, the carbon material is placed on a sieve with 32 μm mesh size, and sieved by gently shaking the sieve for 5 minutes while spraying ion-exchanged water. The first carbon material remaining on the sieve is recovered from the sieve by pouring ion-exchanged water over it, and separated from the ion-exchanged water by filtration. The second carbon material that passed through the sieve is recovered by filtration using a nitrocellulose membrane filter (0.1 μm mesh size). The recovered first carbon material and second carbon material are each dried at a temperature of 110°C for 2 hours. The 32 μm mesh size sieve used is one equipped with a sieve mesh with a nominal mesh size of 32 μm, as specified in JIS Z 8801-1:2006.

[0033] The content of each carbon material in the negative electrode material is determined by measuring the mass of each carbon material separated by the above procedure and calculating the proportion (mass %) of this mass in 5 g of the pulverized sample.

[0034] In this specification, the fully charged state of a lead-acid battery refers to a state in which, for a flooded battery, the battery is charged in a water tank at 25°C at a constant current of 0.2 CA until a voltage of 2.5 V / cell is reached, followed by a further constant current charge of 0.2 CA for 2 hours. For a valve-regulated battery, the fully charged state refers to a state in which the battery is charged in an air tank at 25°C at a constant current and constant voltage of 0.2 CA to a voltage of 2.23 V / cell, and charging is terminated when the charging current during constant voltage charging drops to 1 mCA or less. Note that, in this specification, 1 CA is the current value (A) that is the same as the nominal capacity (Ah) of the battery. For example, for a battery with a nominal capacity of 30 Ah, 1 CA is 30 A, and 1 mCA is 30 mA.

[0035] (A-2) Powder Resistivity of Carbon Materials The powder resistance R1 of the first carbon material and the powder resistance R2 of the second carbon material are values ​​measured by the four-probe method for each of the first carbon material and the second carbon material separated by the procedure in (A-1) above, by putting 0.5 g of a sample into a powder resistance measurement system (MCP-PD51 model, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) and using a low-resistance resistivity meter (Loresta-GX MCP-T700, manufactured by Mitsubishi Chemical Analytech Co., Ltd.) in accordance with JIS K 7194:1994 under a pressure of 3.18 MPa.

[0036] (A-3) Specific Surface Area of ​​Carbon Materials The specific surface area S1 of the first carbon material and the specific surface area S2 of the second carbon material are the BET specific surface areas of the first carbon material and the second carbon material, respectively. The BET specific surface area is determined by a gas adsorption method using the BET equation, using each of the first carbon material and the second carbon material separated by the procedure (A-1) above. 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 using the following apparatus and under the following conditions. Measuring apparatus: TriStar 3000 manufactured by Micromeritics, Inc. Adsorption gas: nitrogen gas with a purity of 99.99% or higher Adsorption temperature: boiling point of liquid nitrogen (77K) Calculation method of BET specific surface area: in accordance with 7.2 of JIS Z 8830:2013

[0037] (A-4) Average aspect ratio of the first carbon material The first carbon material separated by the procedure (A-1) above is observed with an optical microscope or an electron microscope, and 10 or more particles are randomly selected and enlarged photographs are taken. Next, the photographs of each particle are subjected to image processing to determine the maximum particle diameter d1 and the maximum particle diameter d2 in a direction perpendicular to the maximum diameter d1, and the aspect ratio of each particle is determined by dividing d1 by d2. The obtained aspect ratios are averaged to calculate the average aspect ratio.

[0038] (Organic Shrinkage-Preventing Agent) The organic shrinkage-preventing agent contained in the negative electrode material is an organic polymer containing sulfur element, and generally contains one or more, preferably multiple, aromatic rings in the molecule, and also contains sulfur element as a sulfur-containing group. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group, which are stable, is preferred. The sulfonic acid group may exist in an acid form or in a salt form such as a Na salt.

[0039] As the organic shrink-proofing agent, for example, lignins may be used, or synthetic organic shrink-proofing agents may be used. As the synthetic organic shrink-proofing agent, a condensation product of an aromatic compound having a sulfur-containing group with formaldehyde may be used. Examples of lignins include lignin, lignin derivatives such as lignin sulfonic acid or its salts (e.g., alkali metal salts such as sodium salts). One type of organic shrink-proofing agent may be used alone, or two or more types may be used in combination. For example, a lignin may be used in combination with a condensation product of an aromatic compound having a sulfur-containing group with formaldehyde. As the aromatic compound, bisphenols, biphenyls, naphthalenes, etc. are preferably used.

[0040] The content of the organic shrinkage inhibitor in the negative electrode material is, for example, 0.01% by mass or more and 1.0% by mass or less, preferably 0.02% by mass or more and 0.8% by mass or less. These upper and lower limits can be combined arbitrarily.

[0041] The method for quantifying the organic shrinkage inhibitor contained in the negative electrode material is described below. Prior to quantitative analysis, a lead-acid battery after chemical formation is fully charged and then disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water and dried to remove the electrolyte from the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an unpulverized initial sample.

[0042] [Organic shrink-proof agent] An unpulverized initial sample is pulverized, and the pulverized initial sample is immersed in a 1 mol / L NaOH aqueous solution to extract the organic shrink-proof agent. Insoluble components are removed by filtration from the NaOH aqueous solution containing the extracted organic shrink-proof agent. The obtained filtrate (hereinafter also referred to as the filtrate to be analyzed) is desalted, concentrated, and dried to obtain a powder of the organic shrink-proof agent (hereinafter also referred to as the powder to be analyzed). Desalting can be performed by placing the filtrate in a dialysis tube and immersing it in distilled water.

[0043] The organic shrinkage inhibitor is identified by obtaining information from the infrared spectrum of the powder to be analyzed, the ultraviolet-visible absorption spectrum of a solution obtained by dissolving the powder to be analyzed in distilled water or the like, the NMR spectrum of a solution obtained by dissolving the powder to be analyzed in a solvent such as heavy water, and pyrolysis GC-MS, which can obtain information on the individual compounds that make up the substance.

[0044] The ultraviolet-visible absorption spectrum of the filtrate to be analyzed is measured. The content of the organic shrink-preventing agent in the negative electrode material is quantified using the spectral intensity and a previously prepared calibration curve. If the structural formula of the organic shrink-preventing agent to be analyzed cannot be precisely identified and a calibration curve for the same organic shrink-preventing agent cannot be used, a calibration curve is prepared using an available organic shrink-preventing agent that exhibits a similar ultraviolet-visible absorption spectrum, infrared spectrum, NMR spectrum, etc. to the organic shrink-preventing agent to be analyzed.

[0045] (Negative electrode current collector) The lead alloy constituting the negative electrode current collector contains Ca and Sn and may be a Pb-Ca-Sn ternary alloy, or a quaternary or quinary Pb alloy containing Ca, Sn, and an additive element.

[0046] The Ca content in the Pb alloy is greater than 0.06% by mass, preferably greater than 0.065% by mass, and more preferably greater than 0.070% by mass. The Ca content in the Pb alloy is 0.15% by mass or less, preferably 0.12% by mass or less. These lower and upper limits can be arbitrarily combined. The Ca content in the Pb alloy may be, for example, greater than 0.06% by mass and less than 0.12% by mass, 0.065% by mass to 0.15% by mass, 0.065% by mass to 0.12% by mass, 0.070% by mass to 0.15% by mass, or 0.070% by mass to 0.12% by mass. When the Ca content is within this range, corrosion of the edge of the negative electrode plate can be suppressed. This is thought to be because the metal structure is more likely to become finer, slowing down the progression of corrosion. Furthermore, when the Ca content is within this range, corrosion of the lug portions is suppressed and the conductive path can be maintained. By maintaining high conductivity of the lug portions and forming a conductive network in the negative electrode material due to the powder resistivity ratio R2 / R1, the conductivity of the entire negative electrode plate is increased, making it easier to achieve the effects of suppressing lead sulfate accumulation and improving low-temperature high-rate performance. Note that when the Ca content exceeds 0.15% by mass, the lattice strength decreases.

[0047] The Sn content in the Pb alloy may be 0.10% by mass or more and 0.80% by mass or less, and preferably 0.10% by mass or more and 0.75% by mass or less. When the Sn content is within this range, corrosion of the lug of the negative electrode plate can be suppressed for the same reasons as the Ca content. By maintaining high conductivity of the lug and forming a conductive network in the negative electrode material due to the powder resistance ratio R2 / R1, the conductivity of the entire negative electrode is improved, making it easier to achieve the effects of reducing the amount of lead sulfate accumulation and improving low-temperature high-rate performance. If the Sn content is less than 0.10% by mass, crosspiece breakage is likely to occur. In particular, when forming a negative electrode current collector by casting, if the Sn content is less than 0.10% by mass, crosspiece breakage is likely to occur due to reduced melt flow.

[0048] Examples of additive elements in Pb alloys include at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, and Cu. The content of the additive elements in the Pb alloy is, for example, 0.01% by mass or less, and preferably 0.001% by mass or less. In addition to Pb, Ca, Sn, and the above additive elements, the Pb alloy may inevitably contain impurities. The content of the impurities in the Pb alloy is preferably 0.001% by mass or less.

[0049] The content of elements contained in the Pb alloy constituting the negative electrode current collector is determined by performing ICP optical emission spectroscopy on a solution obtained by dissolving the negative electrode current collector in nitric acid using an inductively coupled plasma (ICP) optical emission spectrometer (ICPS-8000, manufactured by Shimadzu Corporation). When analyzing the content of elements in the negative electrode current collector of the negative electrode plate removed from the prepared lead-acid battery, the negative electrode plate is washed with water, dried, and vibrated to remove the negative electrode material from the negative electrode current collector. The negative electrode current collector is then rubbed with a brush or the like to remove all of the negative electrode material, and the negative electrode current collector is used.

[0050] The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or by processing a sheet obtained by rolling a lead or lead alloy slab. Examples of processing methods include expanding and punching.

[0051] (Other) A negative electrode plate can be formed by filling a negative electrode current collector with a negative electrode paste, aging and drying it to produce an unformed negative electrode plate, and then chemically forming the unformed negative electrode plate. The negative electrode paste is produced by adding water and sulfuric acid to lead powder, a carbon material, and, if necessary, an organic shrinkage inhibitor and / or various additives, and kneading them. When aging, it is preferable to age the unformed negative electrode plate at a temperature higher than room temperature and at a high humidity.

[0052] The formation of the negative plates can be carried out by immersing the plate assembly including the unformed negative plates in an electrolyte containing sulfuric acid in a lead-acid battery container and then charging the plate assembly. However, the formation can also be carried out before assembling the lead-acid battery or the plate assembly. The formation produces spongy metallic lead.

[0053] (Positive Electrode Plate) Positive electrode plates for lead-acid batteries are classified into paste type and clad type. Paste type positive electrode plates include a positive electrode current collector and a positive electrode material. The positive electrode material is held by the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and can be formed by casting lead or a lead alloy or processing a lead or lead alloy sheet.

[0054] A clad positive electrode plate includes multiple porous tubes, a metal core inserted into each tube, a current collector connecting the metal cores, a positive electrode material filled into the tubes with the metal cores inserted, and a connecting seat connecting the multiple tubes. The metal cores and the current collector connecting the metal cores are collectively called the positive electrode current collector.

[0055] The lead alloy used for the positive electrode current collector is preferably a Pb—Ca alloy, a Pb—Sb alloy, or a Pb—Ca—Sn alloy from the viewpoints of corrosion resistance and mechanical strength. The positive electrode current collector may have lead alloy layers of different compositions, or may have multiple alloy layers.

[0056] The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that generates capacity through an oxidation-reduction reaction. The positive electrode material may contain other additives as needed.

[0057] Unformed paste-type positive plates are obtained by filling a positive current collector with a positive electrode paste, aging it, and drying it, similar to the case of negative plates. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid.

[0058] The clad type positive electrode plate is formed by filling a tube with lead powder or lead powder slurry into a core metal inserted into the tube, and then joining a plurality of the tubes together with a connecting member.

[0059] The unformed positive plate is then formed. Formation produces lead dioxide. Formation of the positive plate may be performed prior to assembly of the lead-acid battery or plate group.

[0060] (Separator) A separator is usually placed between the negative electrode plate and the positive electrode plate. Nonwoven fabrics, microporous membranes, etc. are used as the separator. The thickness and number of separators to be interposed between the negative electrode plate and the positive electrode plate may be selected according to the inter-electrode distance. Nonwoven fabrics are mats in which fibers are intertwined without being woven, and are primarily composed of fibers. For example, 60% or more by mass of the separator is formed from fibers. Examples of fibers that can be used include glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers such as polyethylene terephthalate fibers), and pulp fibers. Among these, glass fibers are preferred. The nonwoven fabric may contain components other than fibers, such as acid-resistant inorganic powders and polymers as binders.

[0061] On the other hand, a microporous membrane is a porous sheet mainly composed of components other than fiber components, and can be obtained, for example, by extruding a composition containing a pore-forming agent (such as a polymer powder and / or oil) into a sheet, and then removing the pore-forming agent to form pores. Microporous membranes are preferably made of acid-resistant materials, and are preferably composed mainly of polymer components. The polymer component is preferably a polyolefin such as polyethylene or polypropylene.

[0062] The separator may be made of, for example, only a nonwoven fabric or only a microporous membrane. Furthermore, the separator may be a laminate of a nonwoven fabric and a microporous membrane, a laminate of different or the same materials, or a laminate of different or the same materials with recesses and protrusions interlocked, as needed.

[0063] (Electrolyte) The electrolyte is an aqueous solution containing sulfuric acid, and may be gelled as necessary. The specific gravity of the electrolyte at 20°C in a lead-acid battery in a fully charged state after formation is, for example, 1.10 g / cm 3 1.35g / cm or more 3 or less, and 1.20 g / cm 3 1.35g / cm or more 3 It is preferable that:

[0064] FIG. 1 shows the external appearance of an example of a lead-acid battery according to an embodiment of the present invention. The lead-acid battery 1 includes a battery case 12 that contains a plate pack 11 and an electrolyte (not shown). The battery case 12 is divided into multiple cell chambers 14 by partition walls 13. Each cell chamber 14 contains one plate pack 11. The opening of the battery case 12 is sealed with a lid 15 that includes a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a vent plug 18 for each cell chamber. When rehydrating, the vent plug 18 is removed and rehydration solution is added. The vent plug 18 may have the function of venting gas generated in the cell chambers 14 to the outside of the battery.

[0065] Each electrode plate group 11 is formed by stacking a plurality of negative electrode plates 2 and positive electrode plates 3 with separators 4 interposed therebetween. Here, a pouch-shaped separator 4 is shown housing the negative electrode plates 2, but the shape of the separator is not particularly limited. In a cell chamber 14 located at one end of the battery case 12, a negative electrode shelf 6 that connects the ears 2 a of the plurality of negative electrode plates 2 in parallel is connected to a through-connector 8, and a positive electrode shelf 5 that connects the ears 3 a of the plurality of positive electrode plates 3 in parallel is connected to a positive electrode pole 7. The positive electrode pole 7 is connected to a positive electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, a negative electrode pole 9 is connected to the negative electrode shelf 6, and a through-connector 8 is connected to the positive electrode shelf 5. The negative electrode pole 9 is connected to a negative electrode terminal 16 outside the lid 15. Each of the through-connectors 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plate assemblies 11 of adjacent cell chambers 14 in series.

[0066] A lead-acid battery according to one aspect of the present invention is summarized below. (1) One aspect of the present invention is a lead-acid battery comprising: a negative electrode plate and a positive electrode plate; the negative electrode plate comprises a negative electrode current collector and a negative electrode material containing a carbon material; the carbon material comprises 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 powder resistance R2 of the second carbon material to powder resistance R1 of the first carbon material: R2 / R1 is 15 or more and 155 or less; and the negative electrode current collector is made of a Pb alloy containing more than 0.06 mass % but not more than 0.15 mass % Ca and 0.10 mass % but not more than 0.80 mass % Sn.

[0067] (2) In the above (1), it is preferable that 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 20 or more and 240 or less.

[0068] (3) In the above (1) or (2), the average aspect ratio of the first carbon material is preferably 1.5 or more and 30 or less.

[0069] (4) In any one of (1) to (3) above, it is preferable that the content of the first carbon material in the negative electrode material is 0.03 mass% or more and 2.5 mass% or less, and the content of the second carbon material is 0.05 mass% or more and 1.5 mass% or less.

[0070] (5) In any one of the above (1) to (4), it is preferable that the total content of the first carbon material and the second carbon material in the negative electrode material is 0.1 mass % or more and 3.5 mass % or less.

[0071] (6) In any one of the above (1) to (5), the Ca content in the Pb alloy is preferably 0.065% by mass or more and 0.15% by mass or less, more preferably 0.070% by mass or more, and even more preferably 0.12% by mass or less.

[0072] (7) In any one of the above (1) to (6), the Sn content in the Pb alloy is preferably 0.10 mass % or more and 0.75 mass % or less.

[0073] (8) In any one of the above (1) to (7), it is preferable that the first carbon material contains at least graphite, and the second carbon material contains at least carbon black.

[0074] (9) In any one of the above (1) to (8), the ratio R2 / R1 is preferably 15 or more and 152 or less.

[0075] (10) In the above (2), the negative electrode material may further contain an organic shrinkage preventer.

[0076] EXAMPLES The present invention will be specifically described below based on examples and comparative examples, but the present invention is not limited to the following examples.

[0077] Lead acid battery A1 (1) Preparation of negative electrode plate: Lead powder, water, dilute sulfuric acid, a carbon material, and an organic shrinkage preventer are mixed to obtain a negative electrode paste. The negative electrode paste is filled into the mesh portion of an expanded lattice made of a Pb—Ca—Sn alloy as a negative electrode current collector, and the mixture is aged and dried to obtain an unformed negative electrode plate. The Ca content of the Pb—Ca—Sn alloy is 0.09% by mass, and the Sn content is 0.35% by mass.

[0078] As the carbon material, carbon black (average particle diameter D ５０ : 40 nm) and graphite (average particle diameter D ５０ As the organic shrinkage preventive agent, sodium lignin sulfonate is used, and the amount added is adjusted so that the content in 100% by mass of the negative electrode material is 0.05% by mass, and the negative electrode paste is blended with the sodium lignin sulfonate.

[0079] (2) Preparation of Positive Electrode Plate: Lead powder, water, and sulfuric acid are mixed to prepare a positive electrode paste. The positive electrode paste is filled into the mesh of an expanded lattice made of a Pb—Ca—Sn alloy, and the mixture is aged and dried to obtain an unformed positive electrode plate.

[0080] (3) Preparation of lead-acid battery Unformed negative electrode plates were housed in a pouch-shaped separator made of a microporous polyethylene film, and five unformed negative electrode plates and four unformed positive electrode plates per cell formed an electrode plate group.

[0081] The electrode plate group is inserted into a polypropylene battery case, an electrolyte is poured into the battery case, and chemical formation is performed inside the battery case to assemble a flooded lead-acid battery A1 having a nominal voltage of 12 V and a nominal capacity of 30 Ah (5-hour rate).

[0082] In this lead-acid battery, the content of the first carbon material in the negative electrode material is 1.5 mass %, and the content of the second carbon material is 0.3 mass %. The powder resistivity ratio R2 / R1 is 15. The average aspect ratio of the first carbon material is 1.5. 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 20. These values ​​are determined as the content of each carbon material in the negative electrode material (100 mass %) when the negative electrode plate of the fabricated lead-acid battery is removed and the carbon material contained in the negative electrode material is separated into the first carbon material and the second carbon material using the procedure described above. The powder resistivities R1 and R2 of each carbon material, the powder resistivity ratio R2 / R1, the average aspect ratio of the first carbon material, and the specific surface area ratio S2 / S1 are also determined from the fabricated lead-acid battery using the procedure described above.

[0083] <<Lead-acid batteries A2 to A6>> The specific surface area of ​​each carbon material used, the average aspect ratio of the first carbon material, and, if necessary, the average particle diameter D of each carbon material ５０ By adjusting the ratio, the powder resistance ratio R2 / R1 is changed as shown in Table 1. Aside from this, a negative electrode plate is produced in the same manner as for the lead-acid battery A1, and lead-acid batteries A2 to A6 are assembled in the same manner as for the lead-acid battery A1, except that the obtained negative electrode plate is used.

[0084] Lead-acid battery B1: Carbon black (average particle diameter D ５０ Only a Pb-Ca-Sn alloy (40 nm) is used. The Ca content in the Pb-Ca-Sn alloy of the negative electrode current collector is set to 0.06 mass %, and the Sn content is set to 1.00 mass %. Aside from these, a negative electrode plate is formed in the same manner as for the lead-acid battery A1. A lead-acid battery B1 is assembled in the same manner as for the lead-acid battery A1, except for using the obtained negative electrode plate.

[0085] Lead-acid battery B2: Carbon black (average particle diameter D ５０ Only the negative electrode plate (40 nm) is used. A negative electrode plate is formed in the same manner as in the lead-acid battery A1 except for this. A lead-acid battery B2 is assembled in the same manner as in the lead-acid battery A1 except for using the obtained negative electrode plate.

[0086] Lead-acid batteries C1 to C5, D1 to D5, E1 to E5, F1 to F5, G1 to G5, and H1 to H5: The Ca and Sn contents in the Pb-Ca-Sn alloy of the negative electrode current collector are set to the values ​​shown in Table 1. A negative electrode plate is otherwise formed in the same manner as for lead-acid battery A2. Lead-acid batteries C1 to C5, D1 to D5, E1 to E5, F1 to F5, G1 to G5, and H1 to H5 are assembled in the same manner as for lead-acid battery A1, except for using the resulting negative electrode plate.

[0087] Lead-acid batteries J1 to J6: The Pb-Ca-Sn alloy of the negative electrode current collector contains 0.06% Ca and 1.00% Sn by mass. A negative electrode plate is formed in the same manner as for the lead-acid batteries A1 to A6. The lead-acid batteries J1 to J6 are assembled in the same manner as for the lead-acid battery A1, except for using the resulting negative electrode plate.

[0088] Lead-acid battery K1: The Ca content of the Pb—Ca—Sn alloy of the negative electrode current collector is 0.10% by mass, and the Sn content is 1.00% by mass. A negative electrode plate is formed in the same manner as for the lead-acid battery A5. A lead-acid battery K1 is assembled in the same manner as for the lead-acid battery A1, except for using the resulting negative electrode plate.

[0089] Lead-acid battery K2: The Pb-Ca-Sn alloy of the negative electrode current collector contains 0.10% by mass of Ca and 1.00% by mass of Sn. A negative electrode plate is formed in the same manner as for the lead-acid battery A6. A lead-acid battery K2 is assembled in the same manner as for the lead-acid battery A1, except for using the resulting negative electrode plate.

[0090] [Evaluation 1: Corrosion Level] First, in accordance with SBA S 0101:2014, the lead-acid battery was charged and discharged under idle-stop conditions. Specifically, at 25°C, the following (a) to (c) were counted as one cycle and repeated up to 30,000 cycles. A 40-48 hour break was allowed after every 3,600 cycles. (a) Discharge 1: Discharge at a current of 45 A for 59 seconds. (b) Discharge 2: Discharge at a current of 300 A for 1 second. (c) Charge: Charge at a limited current of 100 A and a voltage of 14.0 V for 60 seconds.

[0091] The amount of corrosion of the negative electrode plate lug is evaluated based on the lug thickness. Specifically, first, the lug thickness (initial thickness) of the negative electrode plate before assembling the battery is measured with a vernier caliper. After the above charging and discharging cycles, the battery is disassembled to remove the negative electrode plate. The lug of the negative electrode plate is impregnated with resin, cut so that the cross section of the lug in the thickness direction is exposed, and the cross section is polished. The cross section of the lug is observed under a microscope, and the thickness of the lug at the most corroded location is measured. The lug thickness at this time is then subtracted from the initial thickness (thickness reduction), and the ratio (%) of this value to the initial thickness is taken as the amount of corrosion. Based on this amount of corrosion, the corrosion level is evaluated according to the following criteria. Note that if the lug thickness before assembly is unknown, a lead-acid battery can be obtained and the lug thickness before testing can be measured as a substitute for the lug thickness before assembly. Corrosion level 1: Less than 20% corrosion level Corrosion level 2: 20% to less than 40% corrosion level Corrosion level 3: 40% to less than 60% corrosion level Corrosion level 4: 60% to less than 80% corrosion level Corrosion level 5: 80% or more corrosion level

[0092] [Evaluation 2: Lead Sulfate Accumulation] A lead-acid battery is charged and discharged under the same conditions as in Evaluation 1. After charging and discharging, the negative electrode plate is removed from the lead-acid battery and the amount of lead sulfate accumulated at the bottom of the negative electrode plate (at a position 20% from the bottom of the height of the negative electrode plate) is measured.

[0093] To measure the amount of accumulated lead sulfate, first, the negative electrode plate is removed from the lead-acid battery, washed with water, and vacuum-dried (dried under a pressure lower than atmospheric pressure). The negative electrode material is collected from the bottom of the negative electrode plate and pulverized. Next, a sulfur elemental analyzer (S-200 model, manufactured by LECO Corporation) is used to measure the sulfur content in the pulverized negative electrode material (pulverized sample). The measured sulfur content is then converted to the amount of lead sulfate, and the lead sulfate concentration (mass %) per unit mass of the pulverized sample is calculated, which is used as the amount of accumulated lead sulfate. The amount of accumulated lead sulfate is expressed as a percentage (%), assuming that the amount of accumulated lead sulfate in the negative electrode plate of lead-acid battery B1 is 100.

[0094] [Evaluation 3: Low-Temperature High-Rate (HR) Performance] Charging and discharging of the lead-acid battery was performed under the same conditions as in Evaluation 1. The fully charged lead-acid battery was discharged at a discharge current of 2.6 A at −15° C. until the terminal voltage reached 1 V per cell, and the discharge time was determined. This discharge time was used as an index of low-temperature high-rate performance. The low-temperature high-rate performance was expressed as a percentage (%), with the low-temperature high-rate performance of lead-acid battery B1 being set at 100.

[0095] The results for lead-acid batteries A1 to A6, B1 to B2, C1 to C5, D1 to D5, E1 to E5, F1 to F5, G1 to G5, H1 to H5, J1 to J6, and K1 to K2 are shown in Table 1.

[0096]

[0097] A comparison of lead-acid batteries B1 and B2, in which only the second carbon material was used as the carbon material for the negative electrode plate, shows that when only the second carbon material was used, the corrosion level of the lug was only improved from 5 to 4, even when the composition of the Pb alloy in the negative electrode current collector was controlled. Even when the first carbon material and the second carbon material were used, if the powder resistivity ratio R2 / R1 was less than 15 or more than 155, the corrosion level of the lug was 5, and no corrosion suppression effect was obtained (K1, K2). Furthermore, if the powder resistivity ratio R2 / R1 was less than 15 or more than 155, the corrosion level of the lug was 4, and no significant corrosion suppression effect was obtained (A5, A6), even when the composition of the Pb alloy was controlled.

[0098] Even when the powder resistance ratio R2 / R1 is in the range of 15 to 155, when the Ca content in the Pb alloy is 0.06 mass% or less or exceeds 0.15 mass%, or when the Sn content is less than 0.10 mass% or exceeds 0.80 mass%, the corrosion level is high at 4 to 5 (C1 to C5, D1 to D5, E5, F5, G5, H5, J1 to J6).

[0099] In contrast to these results, when the composition of the Pb alloy is controlled within the powder resistance ratio R2 / R1 range of 15 to 155, the corrosion level of the lug is significantly improved to 2 (A1 to A4, E1 to E4, F1 to F4, G1 to G4, H1 to H4). This is thought to be because the polarization characteristics of the negative electrode plate change, causing the potential of the lug during charge and discharge to deviate from the specific potential at which corrosion progresses.

[0100] Furthermore, controlling the composition of the Pb alloy within the powder resistivity ratio R2 / R1 range of 15 to 155 reduces lead sulfate accumulation and improves low-temperature high-rate performance (A1 to A4, E1 to E4, F1 to F4, G1 to G4, H1 to H4). This is thought to be because controlling the composition of the Pb alloy suppresses corrosion of the negative electrode lug, and setting the powder resistivity ratio R2 / R1 to 15 to 155 facilitates the formation of numerous conductive networks within the negative electrode material, improving the overall conductivity of the negative electrode plate. However, even when the powder resistivity ratio R2 / R1 is within the range of 15 to 155, this effect cannot be achieved if the Ca content in the Pb alloy is 0.06 mass% or less. Furthermore, even when the composition of the Pb alloy is controlled, this effect cannot be achieved when the powder resistivity ratio R2 / R1 is less than 15 or greater than 155.

[0101] <Lead-acid batteries L1 to L5> The specific surface area of ​​each carbon material used is adjusted so that the specific surface area ratio S2 / S1 determined by the procedure described above becomes the value shown in Table 2. A negative electrode plate is otherwise prepared in the same manner as for lead-acid battery A2, and lead-acid batteries L1 to L5 are assembled in the same manner as for lead-acid battery A1, except that the obtained negative electrode plate is used. Lead-acid batteries L1 to L5 are evaluated according to Evaluations 1 to 3 in the same manner as for lead-acid battery A1. The evaluation results are shown in Table 2. Table 2 also shows the results for lead-acid battery A2.

[0102]

[0103] As shown in Table 2, when the specific surface area ratio S2 / S1 is in the range of 20 to 240, the low-temperature high-rate performance is significantly improved (A2, L2 to L4) compared to when the S2 / S1 ratio is outside this range (L1, L5). This is thought to be due to the sufficient shrinkage prevention effect of the organic shrinkage preventive agent. Furthermore, in these lead-acid batteries, the amount of lead sulfate accumulation is maintained at the same level as in the conventional lead-acid battery B1, and corrosion of the terminals is suppressed to level 2.

[0104] <Lead-acid batteries M1 to M5> The average aspect ratio of the carbon material used is adjusted so that the average aspect ratio determined by the procedure described above becomes the value shown in Table 3. A negative electrode plate is otherwise prepared in the same manner as for lead-acid battery L3, and lead-acid batteries M1 to M5 are assembled in the same manner as for lead-acid battery A1, except that the resulting negative electrode plate is used. Lead-acid batteries M1 to M5 are evaluated for Evaluations 1 to 3 in the same manner as for lead-acid battery A1. The evaluation results are shown in Table 3. Table 3 also shows the results for lead-acid battery L3.

[0105]

[0106] As shown in Table 3, when the average aspect ratio of the first carbon material is in the range of 1.5 to 30, the amount of lead sulfate accumulation is significantly reduced and the low-temperature high-rate performance is significantly improved (L3, M2 to M4) compared to when the average aspect ratio is outside this range (M1, M5). The improved low-temperature high-rate performance is believed to be due to the high dispersibility of the components in the negative electrode material, which facilitates the formation of a conductive network within the negative electrode material. The formation of a conductive network is believed to facilitate the reduction of lead sulfate, reducing the amount of lead sulfate accumulation. Furthermore, in these lead-acid batteries, the corrosion level of the ears was 2, demonstrating suppressed corrosion.

[0107] The lead-acid battery according to one aspect of the present invention is suitable for use in vehicles such as automobiles, including vehicles with idle-stop systems. Because corrosion of the lug of the negative electrode plate is suppressed, the battery can also be applied to valve-regulated and flooded lead-acid batteries, and can be used as a power source for starting automobiles or motorcycles, storing natural energy, and as a power source for industrial power storage devices such as electric vehicles (forklifts, etc.).

[0108] REFERENCE SIGNS LIST 1 Lead-acid battery 2 Negative electrode plate 2a Negative electrode plate lug 3 Positive electrode plate 4 Separator 5 Positive electrode shelf 6 Negative electrode shelf 7 Positive electrode column 8 Penetration connector 9 Negative electrode column 11 Electrode plate group 12 Battery case 13 Partition wall 14 Cell chamber 15 Lid 16 Negative electrode terminal 17 Positive electrode terminal 18 Vent plug

Claims

DEPCT631. A lead-acid battery which is a lead-acid battery consisting of an anode plate and a cathode plate. Such cathode plate consists of a cathode capacitor and cathode electrode material incorporated with carbon material. Such carbon material consists of a primary carbon material with a particle size greater than or equal to 32 micrometers and a secondary carbon material with a particle size less than 32 micrometers. The ratio of the resistor powder R2 of the secondary carbon material to the resistor powder R1 of the primary carbon material: R2 / R1 greater than or equal to 15, greater than or equal to 155. Such cathode capacitor consists of a Pb alloy incorporating Ca greater than 0.06% by mass, less than or equal to 0.15% by mass, and Sn greater than or equal to 0.10% by mass, less than or equal to 0.80% by mass.

2. A lead-acid battery specified in Relief 1 in which the ratio of the specific surface area S2 of such secondary carbon material to the specific surface area S1 of such primary carbon material: S2 / S1 greater than or equal to 20. 3.A lead-acid battery specified in Relief 1 or 2 where the ratio of the specific surface area S2 of such second carbon material to the specific surface area S1 of such first carbon material: S2 / S1 is less than or equal to 240. A lead-acid battery specified in any of Reliefs 1-3 where the ratio of the average width-to-length of such first carbon material is greater than or equal to 1.

55. A lead-acid battery specified in any of Reliefs 1-4 where the ratio of the average width-to-length of such first carbon material is less than or equal to 1.

55.

306. Any lead-acid battery specified in Reputations 1-5 in which the composition of such primary carbon material in the anion electrode material is greater than or equal to 0.03% by mass.

7. Any lead-acid battery specified in Reputations 1-6 in which the composition of such primary carbon material in the anion electrode material is less than or equal to 3.0% by mass.

8. Any lead-acid battery specified in Reputations 1-7 in which the composition of such secondary carbon material in the anion electrode material is greater than or equal to 0.03% by mass. 9.

10. Any lead-acid battery specified in any of the claims 1-8 in which the mixture of such secondary carbon material in the anion electrode material is less than or equal to 1.5% by mass; 11. Any lead-acid battery specified in any of the claims 1-9 in which the mixture of such primary and secondary carbon material in the anion electrode material combined is greater than or equal to 0.1% by mass and less than or equal to 3.5% by mass; 12. Any lead-acid battery specified in any of the claims 1-10 in which 12. Any lead-acid battery specified in claims 1-11 in which the Ca content in the Pb alloy is greater than or equal to 0.070% by mass.

13. Any lead-acid battery specified in claims 1-12 in which the Ca content in the Pb alloy is less than or equal to 0.12% by mass.

14. Any lead-acid battery specified in claims 1-13 in which the CaSn content in the Pb alloy is less than or equal to 0.75% by mass. 15.

16. Any lead-acid battery specified in Relief 1-15 where the first carbon electrode is at least composed of graphite and the second carbon electrode is at least composed of carbon black.

17. Any lead-acid battery specified in Relief 2 where the R2 / R1 ratio is less than or equal to 152.

18. Any lead-acid battery specified in Relief 2 where the negative electrode material is additionally composed of an organic anti-shrinkage agent.

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