阅读说明：本技术 铅蓄电池 (Lead-acid battery ) 是由 国泽刚志 松村朋子 于 2018-04-25 设计创作，主要内容包括：铅蓄电池具备负极板和正极板,负极板包含负极电极材料,所述负极电极材料含有碳材料和油。碳材料包含具有32μm以上的粒径的第1碳材料和具有小于32μm的粒径的第2碳材料,第2碳材料的粉体电阻R2与第1碳材料的粉体电阻R1的比：R2/R1为15～155。负极电极材料中的油的含量为0.05质量％～1质量％。(The lead storage battery includes a negative electrode plate and a positive electrode plate, wherein the negative electrode plate includes a negative electrode material containing a carbon material and oil. The carbon material includes a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m, and a ratio of a powder resistance R2 of the 2 nd carbon material to a powder resistance R1 of the 1 st carbon material: R2/R1 is 15 to 155. The content of oil in the negative electrode material is 0.05 to 1 mass%.)

1. A lead-acid battery is provided,

The lead storage battery comprises a negative electrode plate and a positive electrode plate,

The negative electrode plate includes a negative electrode material containing a carbon material and oil,

the carbon material comprises a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m,

A ratio of powder resistance R2 of the 2 nd carbon material to powder resistance R1 of the 1 st carbon material: R2/R1 is 15 to 155,

The content of the oil in the negative electrode material is 0.05 to 1 mass%.

2. The lead storage battery according to claim 1, wherein a ratio of a specific surface area S2 of the 2 nd carbon material to a specific surface area S1 of the 1 st carbon material: S2/S1 is 20 or more.

3. The lead storage battery according to claim 1 or 2, wherein a ratio of a specific surface area S2 of the 2 nd carbon material to a specific surface area S1 of the 1 st carbon material: S2/S1 is 240 or less.

4. A lead storage battery according to any one of claims 1 to 3, wherein the 1 st carbon material has an average aspect ratio of 1.5 or more.

5. The lead-acid battery according to any one of claims 1 to 4, wherein the 1 st carbon material has an average aspect ratio of 30 or less.

6. The lead-acid battery according to any one of claims 1 to 5, wherein the content of the 1 st carbon material in the negative electrode material is 0.05 mass% or more.

7. The lead-acid battery according to any one of claims 1 to 6, wherein the content of the 1 st carbon material in the negative electrode material is 3.0 mass% or less.

8. The lead-acid battery according to any one of claims 1 to 7, wherein the content of the 2 nd carbon material in the negative electrode material is 0.03 mass% or more.

9. The lead-acid battery according to any one of claims 1 to 8, wherein the content of the 2 nd carbon material in the negative electrode material is 1.0 mass% or less.

10. The lead storage battery according to any one of claims 1 to 9, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

Technical Field

The present invention relates to a lead storage battery.

Background

Lead storage batteries are used in various applications, in addition to vehicles and industries. The lead-acid battery includes a negative electrode plate containing a negative electrode material. The manufacturing process of the lead storage battery includes, for example, the following steps: the non-chemically converted negative electrode plate is chemically converted, and then washed with water and dried to obtain a chemically converted (charged) negative electrode plate (negative electrode active material). However, during a period from the production of a chemically converted negative electrode plate to the assembly of a lead-acid battery using the negative electrode plate and the injection of an electrolyte into the lead-acid battery, a negative electrode active material contained in a negative electrode material is oxidized and deteriorated. In particular, in a lead-acid battery of a ready-to-use type in which chemically converted positive and negative electrode plates are stored in a dry state in a battery case during storage of the battery and an electrolyte is injected during use of the battery, the negative electrode plate is exposed to the atmosphere for a long time, and therefore, oxidative degradation of the negative electrode active material is likely to proceed. The initial discharge performance of the lead-acid battery is reduced by oxidative deterioration of the negative electrode active material. Therefore, in order to prevent oxidation of the negative electrode active material, oil is contained in the negative electrode material (patent document 1).

Disclosure of Invention

Lead storage batteries are sometimes used in an undercharged state called a partial state of charge (PSOC). For example, lead storage batteries are often used in a PSOC state when used as a starting power source for automobiles and motorcycles such as charge control vehicles and Idle Stop (IS) vehicles, or as an industrial power storage device for storing natural energy such as sunlight and wind power. Therefore, high life performance in the PSOC cycle is required for the lead storage battery.

In such improvement of the life performance, it is effective to increase the amount of carbon black added to the negative electrode material. However, since the oil is adsorbed by the carbon black, if a large amount of carbon black is added, oxidative deterioration of the negative electrode active material contained in the negative electrode material is likely to occur, and the initial discharge performance is lowered. In order to suppress the decrease in the initial discharge performance, it is considered to increase the amount of oil. However, if the oil is added in a large amount, the charge acceptance performance is lowered.

Thus, it is difficult to improve the life performance in the PSOC cycle without impairing the initial discharge performance and the charge acceptance performance.

One aspect of the present invention is a lead-acid battery including a negative electrode plate and a positive electrode plate, the negative electrode plate including a negative electrode material containing a carbon material and oil, the carbon material including a1 st carbon material having a particle diameter of 32 μm or more and a2 nd carbon material having a particle diameter of less than 32 μm, a ratio of a powder resistance R2 of the 2 nd carbon material to a powder resistance R1 of the 1 st carbon material: 15-155% of R2/R1, and the content of the oil in the negative electrode material is 0.05-1% by mass.

According to the present invention, in a lead-acid battery, the life performance in the PSOC cycle can be improved without impairing the initial discharge performance and the charge acceptance performance.

drawings

Fig. 1 is an exploded perspective view partially cut away showing the external appearance and internal structure of a lead-acid battery according to an embodiment of the present invention.

Detailed Description

One aspect of the present invention is a lead-acid battery including a negative electrode plate and a positive electrode plate, the negative electrode plate including a negative electrode material containing a carbon material and oil. The negative electrode material contains a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m. Ratio of powder resistance R2 of the 2 nd carbon material to powder resistance R1 of the 1 st carbon material: R2/R1 is 15 to 155. The content of oil in the negative electrode material is 0.05 to 1 mass%.

By using 2 carbon materials having different particle diameters and a specific powder resistance ratio in a specific range together with a small amount of oil, the life performance in the PSOC cycle (hereinafter also referred to as PSOC life performance) can be improved. By using 2 kinds of carbon materials having different particle diameters and a powder resistance ratio within a specific range in combination, oxidation of the negative electrode active material can be sufficiently suppressed even when the amount of oil added is small, i.e., 0.05 to 1 mass%, and high initial discharge performance can be obtained. Since the amount of the oil added is small, i.e., 1 mass% or less, a decrease in charge acceptance due to an increase in the amount of the oil added can be avoided.

Among carbon materials, carbon materials having various powder resistances are known. It is known that the powder resistance of a powder material varies depending on the shape, particle diameter, internal structure of particles, crystallinity of particles, and the like. In the conventional technical common knowledge, the powder resistance of the carbon material and the resistance of the negative electrode plate have no direct relationship, and the influence on the PSOC life performance and the initial discharge performance is not considered.

In contrast, according to the above aspect of the present invention, the 1 st carbon material and the 2 nd carbon material having different particle diameters and having a powder resistance ratio in a specific range are used in combination with a small amount of oil, whereby the initial discharge performance can be improved. This is considered to be because the adsorption of oil to the 2 nd carbon material can be suppressed to be remarkable, and even if the amount of oil is small, the effect of oil can be sufficiently exhibited.

In the above aspect of the present invention, by controlling the powder resistance ratio R2/R1 of the 2 nd carbon material to the 1 st carbon material contained in the negative electrode plate to be in the range of 15 to 155, high PSOC life performance can be obtained. This is presumed to be due to the following reason. First, by controlling the powder resistance ratio R2/R1 in the above range, a conductive network is easily formed in the negative electrode material. Further, by controlling the oil content to 0.05 to 1 mass%, the oxidation of the negative electrode active material can be suppressed without adversely affecting the formation of the conductive network. Since oxidation of the negative electrode active material is suppressed, the function of the conductive network can be sufficiently exhibited. In addition, since the amount of oil is small, the formation of the conductive network is not adversely affected, and the formed conductive network is easily maintained even when the PSOC cycle is performed.

(oil)

Examples of the oil include paraffin-based oil, naphthene-based oil, olefin-based oil, aromatic-based oil, and silicone-based oil. Commercially available oils contain various additives such as antioxidants. Oils containing appropriate amounts of various additives within the range generally used may be used.

The content of oil in the negative electrode material is 0.05 to 1 mass%. In this case, excellent PSOC life performance, initial discharge performance, and charge acceptance performance can be obtained. When the content of the oil in the negative electrode material is less than 0.05 mass%, the initial discharge performance is lowered. When the content of the oil in the negative electrode material exceeds 1 mass%, the charge acceptance is lowered. The content of the oil in the negative electrode material is preferably 0.05 to 0.5 mass%. At this time, the PSOC life performance and the charge acceptance performance are further improved.

The content of the oil in the negative electrode material is a mass ratio of the oil in the negative electrode material contained in the chemically converted negative electrode plate (before the electrolyte is injected into the lead-acid battery) after the steps of chemical conversion, washing with water, and drying. In the case of a lead-acid battery, the oil content in the negative electrode material during storage of the battery is referred to.

Hereinafter, measurement of the oil content in the negative electrode material will be described.

(A) Determination of the oil content

The negative electrode material is separated from the chemically converted negative electrode plate after the steps of chemical conversion, washing with water, and drying. Alternatively, the lead-acid battery before the electrolyte is injected is decomposed to take out a chemically converted negative electrode plate, and the negative electrode material is separated from the negative electrode plate. The negative electrode material was pulverized to obtain a sample powder having a mass Ma. N-hexane was added to the sample powder to obtain a sample liquid. The sample solution was heated at 65 ℃ for 1 hour. Thereafter, the sample solution was filtered to obtain a filtrate. The filtrate was heated at 65 ℃ for 1 hour to give a residue. The residue is weighed and taken as the mass Mb of the oil. The oil content in the negative electrode material was determined from the following equation using Ma and Mb described above.

The content (%) of oil in the negative electrode material was (mass Mb/mass Ma) × 100

Even in the case of a lead-acid battery (other than a ready-to-use lead-acid battery) into which an electrolyte is injected, the oil content in the negative electrode material is determined by the following procedure in the case of an unused lead-acid battery.

The negative electrode plate was taken out from the lead-acid battery containing the electrolyte, washed with water to remove the sulfuric acid component, and vacuum-dried (dried under a pressure lower than atmospheric pressure). Thereafter, the negative electrode material was separated from the negative electrode plate, and the oil content in the negative electrode material was determined by the above-described method.

In the above-described unused battery, the oil in the negative electrode plate hardly flows out into the electrolytic solution. However, when the battery is left for a long time, the state of the battery (negative electrode plate) may change, and therefore, the above-described unused battery is a battery immediately after production (within 1 month from production).

(carbon Material)

The carbon material includes a1 st carbon material having a particle diameter of 32 μm or more and a2 nd carbon material having a particle diameter of less than 32 μm. The 1 st carbon material and the 2 nd carbon material are separated and distinguished by the steps described later.

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

The carbon material 1 has an intensity ratio ID/IG of 0 to 0.9 between a peak (D band) appearing in a range of 1300cm-1 to 1350cm-1 in a Raman spectrum and a peak (G band) appearing in a range of 1550cm-1 to 1600cm-1 as graphite.

The carbon material 1 and the carbon material 2 are each a carbon material having a powder resistance R2 of the carbon material 2 and a powder resistance R1 of the carbon material 1 in a ratio of: the type of each carbon material may be selected so that R2/R1 is 15 to 155, or the particle size, specific surface area, aspect ratio, or the like of each carbon material may be adjusted.

The 1 st carbon material is preferably at least one selected from graphite, hard carbon, and soft carbon, for example. In particular, the 1 st carbon material preferably contains at least graphite. The 2 nd carbon material preferably contains at least carbon black. When these carbon materials are used, the powder resistance ratio R2/R1 can be easily adjusted.

When the powder resistance ratio R2/R1 is 15 to 155, excellent PSOC life performance, initial discharge performance and charge acceptance performance can be obtained. The powder resistance ratio R2/R1 is preferably 55 to 155, more preferably 55 to 130. In this case, excellent PSOC life performance, initial performance, and charge acceptance performance can be obtained in a more balanced manner.

Ratio of specific surface area S2 of the 2 nd carbon material to specific surface area S1 of the 1 st carbon material: the S2/S1 is, for example, 10 to 550. The specific surface area ratio S2/S1 is preferably 20 to 240. In this case, excellent PSOC life performance, initial discharge performance, and charge acceptance performance can be obtained in a well-balanced manner. When the ratio of S2/S1 is 20 or more, the specific surface area of each carbon material is in an appropriate range, whereby the adsorption of oil can be further suppressed. As a result, the initial discharge performance is further improved. When S2/S1 is 240 or less, since the reduction reaction of lead sulfate is easily progressed, high PSOC life performance can be ensured and the charge acceptance performance is further improved.

The carbon material 1 has an average aspect ratio of, for example, 1 to 200. The average aspect ratio of the carbon material 1 is preferably 1 or more, and more preferably 1.5 or more. Further, it is preferably 100 or less, more preferably 35 or less, and further preferably 30 or less. These upper and lower limits may be arbitrarily combined.

When the average aspect ratio of the 1 st carbon material is 1.5 to 30, the PSOC lifetime performance can be further improved while maintaining good initial discharge performance and charge acceptance performance. This is considered to be because when the average aspect ratio is in such a range, a conductive network is easily formed in the negative electrode material, and the formed conductive network is easily maintained.

When the average aspect ratio of the 1 st carbon material is 1.5 or more, the carbon material can be inhibited from flowing out into the electrolyte solution with repeated charge and discharge, and therefore the effect of improving the PSOC lifetime performance can be further increased. In addition, when the average aspect ratio of the 1 st carbon material is 30 or less, the adhesion between the active material particles is easily ensured, and therefore, the occurrence of cracks in the negative electrode plate can be suppressed, and the reduction in lifetime performance can be suppressed.

The average aspect ratio of the carbon number 1 is more preferably 5 to 30, and still more preferably 10 to 30, from the viewpoint of obtaining excellent PSOC life performance, initial discharge performance, and charge acceptance performance in a well-balanced manner.

The content of the 1 st carbon material in the negative electrode material is, for example, 0.05 to 3.0 mass%. Preferably 0.1% by mass or more, and more preferably 0.4% by mass or more. Further, it is preferably 2.0% by mass or less, and more preferably 2.0% by mass or less. These upper and lower limits may be arbitrarily combined. When the content of the 1 st carbon material in the negative electrode material is 0.05 mass% or more, the effect of improving the PSOC lifetime performance can be further increased. When the content of the 1 st carbon material in the negative electrode material is 3.0 mass% or less, the adhesion between the active material particles is easily ensured, and therefore, the occurrence of cracks in the negative electrode plate can be suppressed, and high PSOC life performance can be more easily ensured.

The content of the 2 nd carbon material in the negative electrode material is, for example, 0.03 to 3.0 mass%. Preferably 0.05 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 may be arbitrarily combined. When the content of the 2 nd carbon material in the negative electrode material is 0.03 mass% or more, the PSOC life performance can be further improved. When the content of the 2 nd carbon material in the negative electrode material is 3.0 mass% or less, the adsorption of oil can be further suppressed, and the initial discharge performance can be further improved.

The content of each carbon material in the negative electrode material was determined by the procedure (B-1) described later.

The method of determining the physical properties of the carbon material or the method of analyzing the same will be described below.

(B) Analysis of carbon Material

(B-1) separation of carbon Material

in the case of a lead-acid battery having chemically converted positive and negative electrode plates before the electrolyte is injected, the battery is disassembled and the chemically converted negative electrode plate in a dry state is taken out. In the case of an unused lead acid battery including chemically converted positive and negative electrode plates and having an electrolyte injected therein immediately after production (within 1 month from production), the lead acid battery is disassembled, the chemically converted negative electrode plate is taken out, sulfuric acid is removed by washing with water, and vacuum drying (drying at a pressure lower than atmospheric pressure) is performed. Next, the negative electrode material is collected from the dried negative electrode plate and pulverized. 30mL of a 60 mass% nitric acid aqueous solution was added to 5g of the pulverized sample, and the mixture was heated at 70 ℃. Further, 10g of disodium ethylenediaminetetraacetate, 30mL of 28 mass% aqueous ammonia and 100mL of water were added thereto, and heating was continued to dissolve soluble substances. The sample thus pretreated was collected by filtration. The collected sample was passed through a sieve having a mesh size of 500 μm to remove large-sized components such as reinforcing materials, and the components passing through the sieve were collected as a carbon material.

When the collected carbon material is wet-sieved using a sieve having a mesh size of 32 μm, the carbon material that does not pass through the mesh size of the sieve and remains on the sieve is referred to as a1 st carbon material, and the carbon material that passes through the mesh size of the sieve is referred to as a2 nd carbon material. That is, the particle diameter of each carbon material is based on the size of the mesh of the sieve. Wet screening may be performed according to JIS Z8815: 1994.

Specifically, the carbon material was placed on a sieve having a mesh size of 32 μm, and the sieve was gently shaken while spraying ion exchange water for 5 minutes to perform sieving. The carbon material 1 left on the screen washes the ion-exchanged water to recover it from the screen, and separates it from the ion-exchanged water by filtration. The 2 nd carbon material having passed through the sieve was recovered by filtration using a membrane filter (mesh size: 0.1 μm) made of nitrocellulose. The recovered 1 st carbon material and 2 nd carbon material were dried at a temperature of 110 ℃ for 2 hours, respectively. As a sieve having a mesh size of 32 μm, a sieve having a mesh size of JIS Z8801-1: a sieve having a mesh with a nominal mesh size of 32 μm as defined in 2006.

The content of each carbon material in the negative electrode material was determined by measuring the mass of each carbon material separated in the above-described step and calculating the ratio (% by mass) of the mass to 5g of the pulverized sample.

(B-2) powder resistance of carbon Material

The powder resistance R1 of the 1 st carbon material and the powder resistance R2 of the 2 nd carbon material were measured by charging 0.5g of a sample into each of the 1 st carbon material and the 2 nd carbon material separated in the step (B-1) in a powder resistance measuring system (MCP-PD 51, manufactured by Mitsubishi Chemical Analytech) under a pressure of 3.18MPa in accordance with JIS K7194: 1994 (manufactured by Mitsubishi Chemical Analytech, Loresta GX MCP-T700), by the four-probe method.

(B-3) specific surface area of carbon Material

the specific surface areas S1 and S2 of the 1 st carbon material and the 2 nd carbon material are BET specific surface areas of the 1 st carbon material and the 2 nd carbon material, respectively. The BET specific surface area was determined by the BET formula using the 1 st carbon material and the 2 nd carbon material separated in the above-described step (B-1) by a gas adsorption method. Each carbon material was pretreated by heating at 150 ℃ for 1 hour in a nitrogen stream. Using the pretreated carbon material, the BET specific surface area of each carbon material was determined under the following conditions using the following apparatus.

A measuring device: TriStar3000 manufactured by Micromeritics

Adsorbing gas: nitrogen with purity over 99.99 percent

Adsorption temperature: boiling point temperature of liquid nitrogen (77K)

Method for calculating BET specific surface area: according to JIS Z8830: 2013 7.2

(B-4) average aspect ratio of carbon Material 1

The 1 st carbon material separated in the step (B-1) was observed with an optical microscope or an electron microscope, and any particle having 10 or more particles was selected and a magnified photograph thereof was taken. Next, the image of each particle was processed to determine the maximum particle diameter d1 of the particle and the maximum particle diameter d2 in the direction perpendicular to the maximum particle diameter d1, and the aspect ratio of each particle was determined by dividing d1 by d 2. The average aspect ratio was calculated by averaging the obtained aspect ratios.

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described with respect to the main constituent elements, but the present invention is not limited to the following embodiment.

(negative plate)

The negative plate of the lead storage battery comprises a negative electrode material. The negative electrode plate may be generally composed of a negative electrode grid (negative electrode collector) and a negative electrode material. The negative electrode material is obtained by removing the negative current collector from the negative electrode plate.

The negative electrode plate may be attached with a member such as a spacer or a pasting paper. When the negative electrode plate includes such a member (attached member), the negative electrode material refers to a portion other than the negative electrode current collector and the attached member. However, the thickness of the electrode plate is the thickness including the gasket. When the spacer is attached with the spacer, the thickness of the spacer is included in the thickness of the spacer.

The negative electrode material preferably contains a negative active material (lead or lead sulfate) that exhibits capacity by an oxidation-reduction reaction. The negative electrode active material in a charged state is spongy lead, but a negative electrode plate that is not chemically converted is generally made using lead powder. The negative electrode material comprises the carbon material and oil already described. The negative electrode material may further contain an organic shrink inhibitor, barium sulfate, or the like, and may also contain other additives as necessary. As the organic shrink preventive, lignin (lignin sulfonic acid or a salt thereof) or the like can be used.

The content of the organic shrink preventing agent contained in the negative electrode material is, for example, preferably 0.01 mass% or more, more preferably 0.02 mass% or more, and still more preferably 0.05 mass% or more. On the other hand, it is preferably 1.0% by mass or less, more preferably 0.8% by mass or less, and still more preferably 0.5% by mass or less. These lower limit value and upper limit value may be arbitrarily combined. Here, the content of the organic shrinkproof agent contained in the negative electrode material refers to the content of the negative electrode material collected from the lead-acid battery in a chemically converted fully charged state by the method described later.

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, and may be 0.5 mass% or more, may be 1.0 mass% or more, and may be 1.3 mass% or more. On the other hand, it is preferably 3.0% by mass or less, more preferably 2.5% by mass or less, and further preferably 2% by mass or less. These lower limit value and upper limit value may be arbitrarily combined.

Hereinafter, a method for determining the organic shrinkage inhibitor and barium sulfate contained in the negative electrode material will be described. Before quantitative analysis, the lead-acid battery after chemical conversion is fully charged and disassembled to obtain a negative electrode plate to be analyzed. The obtained negative electrode plate was washed with water and dried to remove the electrolyte from the negative electrode plate. Next, the negative electrode material was separated from the negative electrode plate to obtain an initial sample that was not pulverized.

[ organic shrinkproof agent ]

The non-pulverized initial sample was pulverized, and the pulverized initial sample was immersed in a 1mol/L NaOH aqueous solution to extract the organic anti-shrinking agent. Insoluble components were removed from the aqueous NaOH solution containing the extracted organic anti-shrink agent by filtration. The filtrate thus obtained (hereinafter also referred to as filtrate to be analyzed) is desalted and then concentrated and dried to obtain powder of the organic anti-shrinking agent (hereinafter also referred to as powder to be analyzed). Desalting is carried out by filling the filtrate in a dialysis tube and immersing the tube in distilled water.

The organic shrink preventive is identified by obtaining information from an infrared spectrum of a powder to be analyzed, an ultraviolet-visible absorption spectrum of a solution obtained by dissolving the powder to be analyzed in distilled water or the like, an NMR spectrum of a solution obtained by dissolving the powder to be analyzed in a solvent such as heavy water, or thermal cracking GC-MS or the like from which information on each compound constituting the substance can be obtained.

The ultraviolet-visible absorption spectrum of the filtrate to be analyzed was measured. The content of the organic shrinkproof agent in the negative electrode material was quantified using the spectral intensity and a calibration curve prepared in advance. When the structural formula of the organic shrinkproof agent to be analyzed cannot be determined precisely and a calibration curve of the same organic shrinkproof agent cannot be used, a calibration curve is prepared using an organic shrinkproof agent that can be obtained and shows an ultraviolet-visible absorption spectrum, an infrared spectrum, an NMR spectrum, or the like similar to that of the organic shrinkproof agent to be analyzed.

[ barium sulfate ]

The initial sample which had not been pulverized was pulverized, and 50ml of (1+2) nitric acid was added to 10g of the pulverized initial sample, and the mixture was heated for about 20 minutes to dissolve the lead component as lead nitrate. Next, the solution containing lead nitrate is filtered to remove solid components such as carbonaceous materials and barium sulfate.

After the obtained solid content was dispersed in water to prepare a dispersion, components (for example, a reinforcing material) other than the carbonaceous material and barium sulfate were removed from the dispersion by using a sieve. Next, the dispersion was subjected to suction filtration using a membrane filter whose mass was measured in advance, and the membrane filter was dried together with the filtered sample using a dryer at 110 ℃. The filtered sample is a mixed sample of carbonaceous material and barium sulfate. The mass (a) of the mixed sample was measured by subtracting the mass of the membrane filter from the total mass of the dried mixed sample and the membrane filter. Thereafter, the dried mixed sample is put into a crucible together with a membrane filter, and is subjected to burning ashing at 700 ℃ or higher. The residue remained as barium oxide. The mass of barium sulfate was determined by converting the mass of barium oxide to the mass of barium sulfate (B).

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 an expanding processing (expanding) and a Punching processing (Punching).

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 1 kind selected from Ba, Ag, Al, Bi, As, Se, Cu, and the like As an additive element.

The negative electrode plate can be formed by filling the negative electrode paste into the negative electrode current collector, aging and drying the negative electrode paste to produce a non-chemically-converted negative electrode plate, and then chemically converting the non-chemically-converted negative electrode plate. Sponge lead is generated through chemical conversion. The negative electrode paste is prepared by adding water and sulfuric acid to lead powder, an organic shrinkproof agent, and various additives as needed, and kneading them. In the aging, the negative electrode plate that has not been chemically converted is preferably aged at a temperature higher than room temperature and at a high humidity.

(Positive plate)

The positive electrode plate of the lead-acid battery has a paste type and a clad (cladding) type.

The paste-type positive electrode plate is provided with a positive electrode collector and a positive electrode material. The positive electrode material is held by the positive 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 a lead alloy sheet.

The clad positive electrode plate includes a plurality of porous tubes, a core rod inserted into each tube, a current collecting portion connecting the core rods, a positive electrode material filled in the tube into which the core rod is inserted, and a connecting seat connecting the plurality of tubes. The mandrel and the current collecting portion to which the mandrel is connected are collectively referred to as a positive electrode current collector.

The lead alloy used for the positive electrode current collector is preferably a Pb — Ca alloy or a Pb — Ca — Sn alloy in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have lead alloy layers having different compositions, and the number of the alloy layers may be plural. As the plug, a Pb-Ca alloy, a Pb-Sb alloy, or the like can be used.

the positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) that exhibits capacity by an oxidation-reduction reaction. The positive electrode material may contain other additives as needed.

The paste-type positive electrode plate that is not chemically converted can be obtained by filling a positive electrode paste into a positive electrode current collector, aging the positive electrode paste, and drying the cured positive electrode paste, depending on the case of the negative electrode plate. Thereafter, the positive electrode plate that has not been chemically converted is chemically converted. The positive electrode paste can be prepared by kneading lead powder, an additive, water, and sulfuric acid. In the aging, the chemically unconverted positive electrode plate is preferably aged at a temperature higher than room temperature and at a high humidity.

The clad positive electrode plate can be formed by filling a tube into which a core rod is inserted with lead powder or slurry-like lead powder and joining the plurality of tubes with a joint.

(spacer)

A separator is generally disposed between the negative electrode plate and the positive electrode plate. The separator may be a nonwoven fabric, a microporous film, or the like. The thickness and the number of the separators interposed between the negative electrode plate and the positive electrode plate may be selected according to the inter-electrode distance.

The nonwoven fabric is a mat formed by complexing nonwoven fibers, and mainly comprises fibers. For example, 60% by mass or more of the separator is formed of fibers. As the fibers, glass fibers, polymer fibers (polyolefin fibers, acrylic fibers, polyester fibers such as polyethylene terephthalate fibers, and the like), pulp fibers, and the like can be used. Among them, glass fiber is preferable. The nonwoven fabric may contain components other than fibers, such as acid-resistant inorganic powder, a polymer as a binder, and the like.

On the other hand, the microporous membrane is a porous sheet mainly composed of other than the fiber component, and can be obtained, for example, by extrusion-molding a composition containing a pore-forming agent (polymer powder, oil, or the like) into a sheet shape, and then removing the pore-forming agent to form pores. The microporous membrane is preferably made of a material having acid resistance, and preferably mainly contains a polymer component. As the polymer component, polyolefins such as polyethylene and polypropylene are preferable.

The separator may be composed of only a nonwoven fabric or only a microporous film, for example. The separator may be a laminate of a nonwoven fabric and a microporous film, a laminate of different types or the same type of materials with irregularities engaged therein, or the like, as required.

(electrolyte)

The electrolyte is an aqueous solution containing sulfuric acid, and may be gelled as necessary. The specific gravity of the electrolyte in the lead-acid battery in a fully charged state after chemical conversion at 20 ℃ is, for example, 1.10 to 1.35g/cm3, preferably 1.20 to 1.35g/cm 3.

Generally, an electrode plate group is formed by using positive and negative electrode plates that have not been chemically converted, and after the electrode plate group is stored in a battery case, an electrolyte is injected into the battery case to chemically convert the positive and negative electrode plates that have not been chemically converted. On the other hand, in the case of a lead-acid battery of the ready-to-use type, the electrode plate group is formed by using chemically converted positive and negative electrode plates and is accommodated in the battery case. Since the chemically converted positive and negative electrode plates are stored in a dry state in the battery case during storage of the battery, the electrolyte is injected into the battery case to use the battery. The oil contained in the negative electrode material can suppress oxidative deterioration of the negative electrode active material during storage until the electrolyte solution is injected.

Fig. 1 shows an external appearance of an example of a lead-acid battery according to an embodiment of the present invention.

The lead storage battery 1 includes a battery case 12 that accommodates an electrode group 11 and an electrolyte (not shown). The battery case 12 is partitioned into a plurality of battery cell chambers 14 by partition walls 13. Each cell chamber 14 accommodates 1 electrode group 11. The opening of the battery case 12 is sealed by a lid 15 provided with a negative electrode terminal 16 and a positive electrode terminal 17. A liquid port plug 18 is provided on the cover 15 for each cell chamber. When water is supplemented, the liquid opening plug 18 is taken down to supplement the water supplementing liquid. The liquid port plug 18 may have a function of discharging gas generated in the cell chamber 14 to the outside of the battery.

The electrode group 11 may be formed by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 with separators 4 interposed therebetween. Here, the bag-like separator 4 that houses the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. In battery cell chamber 14 located at one end of battery can 12, negative electrode holder 6, which connects lug portions 2a of negative electrode plates 2 in parallel, is connected to penetrating connector 8, and positive electrode holder 5, which connects lug portions 3a of positive electrode plates 3 in parallel, is connected to positive post 7. The positive post 7 is connected to a positive terminal 17 outside the cover 15. In battery cell chamber 14 located at the other end of battery container 12, negative pole column 9 is connected to negative pole frame portion 6, and through connector 8 is connected to positive pole frame portion 5. The negative electrode tab 9 is connected to a negative electrode terminal 16 on the outside of the cover 15. Each of the penetration connectors 8 connects the electrode plate groups 11 of the adjacent battery cell chambers 14 in series through the penetration holes provided in the partition walls 13.

The negative electrode plate for a lead-acid battery according to one aspect of the present invention is described below in summary.

(1) One aspect of the present invention is a lead-acid battery,

The lead-acid battery comprises a negative electrode plate and a positive electrode plate,

The negative electrode plate comprises a negative electrode material containing a carbon material and an oil,

The carbon material comprises a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m,

A ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material: R2/R1 is 15 to 155,

The content of the oil in the negative electrode material is 0.05 to 1 mass%.

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

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

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

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

(6) In any one of the above (1) to (5), the content of the 1 st carbon material in the negative electrode material is preferably 0.05% by mass or more.

(7) In any one of the above (1) to (6), the content of the 1 st carbon material in the negative electrode material is preferably 3.0% by mass or less.

(8) In any one of the above (1) to (7), the content of the 2 nd carbon material in the negative electrode material is preferably 0.03 mass% or more.

(9) In any one of the above (1) to (8), the content of the 2 nd carbon material in the negative electrode material is preferably 1.0 mass% or less.

(10) In any one of the above (1) to (9), it is preferable that the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.