CN110754010A - Lead-acid battery - Google Patents

Abstract

A lead storage battery includes a negative electrode plate, a positive electrode plate, and an electrolyte. The negative electrode plate contains a negative electrode material containing a carbon material and an organic shrinkage inhibitor, and the carbon material includes a1 st carbon material having a particle size of 32 [ mu ] m or more and a2 nd carbon material having a particle size of less than 32 [ mu ] m. The ratio R2/R1 between the powder resistance R2 of the 2 nd carbon material and the powder resistance R1 of the 1 st carbon material is 15 to 155. The organic shrink-proofing agent comprises a1 st organic shrink-proofing agent having an aromatic ring and a2 nd organic shrink-proofing agent having an aromatic ring. The content of the sulfur element in the 1 st organic shrink-proof agent is more than 4000 mu mol/g, and the content of the sulfur element in the 2 nd organic shrink-proof agent is less than 2000 mu mol/g.

Description

Lead-acid battery

Technical Field

The present invention relates to a lead storage battery.

Background

Lead storage batteries can be used for various purposes other than vehicle use and industrial use. The lead storage battery includes a negative plate, a positive plate, and an electrolyte. The negative electrode plate contains a current collector and a negative electrode material. An organic shrink-proof agent is added to the negative electrode material. For example, patent document 1 proposes adding sodium lignin sulfonate to the negative electrode plate. Patent document 2 proposes adding a bisphenol sulfonic acid polymer and sodium lignosulfonate to a negative electrode plate.

Documents of the prior art

Patent document

Patent document 1 International publication No. 2015/087749 booklet

Patent document 2 International publication No. 2012/017702 booklet

Disclosure of Invention

Lead storage batteries are sometimes used in an undercharged state called a partial state of charge (PSOC). For example, in charge control and Idle Start Stop (ISS), the lead-acid battery is used under PSOC. Therefore, lead storage batteries are required to have excellent life performance in a cycle test under PSOC conditions (hereinafter referred to as PSOC life performance). For such improvement of the life performance, it is effective to increase the amount of carbon black added to the negative electrode material. However, since lignin (including lignosulfonic acid or its salt, etc.) of the organic shrinkproof agent is adsorbed by carbon black, if a large amount of carbon black is added, the negative electrode material shrinks, and the low-temperature high-rate performance after high-temperature cycles is degraded.

One aspect of the present invention relates to a lead-acid battery in which,

the lead storage battery comprises a negative electrode plate, a positive electrode plate and an electrolyte,

the negative electrode plate contains a negative electrode material containing a carbon material and an organic shrinkproof agent,

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 organic shrink-proofing agent comprises a1 st organic shrink-proofing agent having an aromatic ring and a2 nd organic shrink-proofing agent having an aromatic ring,

the content of sulfur element in the No. 1 organic shrink-proof agent is more than 4000 mu mol/g,

the content of sulfur element in the No. 2 organic shrink-proofing agent is less than 2000 mu mol/g.

Effects of the invention

In a lead-acid battery, high PSOC life performance is ensured, and low-temperature high-rate performance after high-temperature cycling is improved.

Drawings

Fig. 1 is an exploded perspective view partially cut away to show 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, a positive electrode plate, and an electrolyte. The negative electrode plate contains a negative electrode material containing a carbon material and an organic shrinkproof agent. The carbon material includes a carbon material (1 st carbon material) having a particle diameter of 32 μm or more and a carbon material (2 nd carbon material) having a particle diameter of less than 32 μm. 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 organic shrink proofing agent comprises a1 st organic shrink proofing agent having an aromatic ring and a2 nd organic shrink proofing agent having an aromatic ring. The content of sulfur element in the No. 1 organic shrink-proof agent is more than 4000 mu mol/g, and the content of sulfur element in the No. 2 organic shrink-proof agent is less than 2000 mu mol/g.

In the present specification, the content of the sulfur element in the organic shrinkproof agent of X. mu. mol/g means that the content of the sulfur element in 1g of the organic shrinkproof agent is X. mu. mol.

In general, carbon black is added to the negative electrode material from the viewpoint of improving conductivity. However, it is known that carbon black is easily aggregated in a negative electrode material and hardly forms a conductive network, and thus it is difficult to obtain sufficient PSOC life performance. Therefore, it has been conventionally considered that it is advantageous to increase the amount of carbon black to be added from the viewpoint of improving the PSOC life performance. On the other hand, conventionally, lignin has been commonly used as an organic shrinkproof agent in negative electrode materials. However, in this case, since the carbon black adsorbs lignin, if the amount of carbon black added is increased, the shrinkage of the negative electrode material accompanying the adsorption of lignin becomes remarkable, and as a result, the low-temperature high-rate performance after high-temperature cycles is remarkably lowered. In addition, synthetic organic shrinkproof agents are sometimes used in conventional negative electrode materials. However, it is known that when carbon black is added to a negative electrode material using a synthetic shrinkproof agent, the synthetic organic shrinkproof agent flows out during high-temperature cycles, and the pore structure of the negative electrode material cannot be maintained, thereby degrading PSOC life performance.

Unlike the above-described aspects of the present invention, when the 2 nd organic shrink preventing agent is used alone, it is difficult to improve the low-temperature high-rate performance after high-temperature cycles even if a large amount of the 2 nd organic shrink preventing agent is added to the negative electrode material. This is because the No. 2 organic shrink-proofing agent easily flows out from the negative electrode material at the time of high-temperature cycle. In addition, if the 1 st organic shrink proofing agent is used, the liquid reduction amount of the electrolyte after circulation is increased, so from the viewpoint of suppressing the liquid reduction amount to be low, it is generally difficult to increase the amount of the 1 st organic shrink proofing agent used. Therefore, even if the 1 st organic shrink preventing agent is used alone in an amount in which the liquid reducing amount is not significant, it is difficult to sufficiently improve the PSOC life performance. Further, when two kinds of organic shrinkproof agents are used in combination, when an organic shrinkproof agent having a sulfur element content of 2000. mu. mol/g or less and an organic shrinkproof agent having a sulfur element content of more than 2000. mu. mol/g and less than 4000. mu. mol/g are used, the effect of improving the low-temperature high-rate performance after high-temperature cycles is insufficient. The detailed reason is not clear, but it is presumed that in this case, the organic shrinkage preventing agent easily flows out from the negative electrode material during high-temperature cycles, and it is difficult to maintain the pore structure of the negative electrode material.

In addition, 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 sense, it is considered that the powder resistance of the carbon material and the resistance of the negative plate have no direct relationship, and have no influence on the PSOC life performance and the low-temperature high-rate performance after high-temperature cycling.

In contrast, according to the above aspect of the present invention, the 1 st organic shrink preventing agent having an elemental sulfur content of 4000. mu. mol/g or more and the 2 nd organic shrink preventing agent having an elemental sulfur content of 2000. mu. mol/g or less are combined, and the 1 st carbon material and the 2 nd carbon material are used. The 1 st carbon material and the 2 nd carbon material have different particle diameters, and the powder resistance ratio R2/R1 is in the range of 15 to 155. In this manner, in the above-described side surface, by combining the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent, and combining the 1 st carbon material and the 2 nd carbon material, the low-temperature high-rate performance after the battery is repeatedly charged and discharged at a high temperature (after high-temperature cycles) can be improved. This is considered to be because the 2 nd organic shrinkproof agent is inhibited from significantly adsorbing to the 2 nd carbon material. In addition, it is considered that the low-temperature high-rate performance is also improved by suppressing the outflow of the organic shrinkage-preventing agent from the negative electrode material during high-temperature cycles, and maintaining the pore structure of the negative electrode material. This is presumed to be because the combination of the 1 st organic shrinkproof agent having a sulfur element content of 4000. mu. mol/g or more with the 2 nd organic shrinkproof agent facilitates formation of colloidal particles of the 1 st organic shrinkproof agent having an appropriate particle diameter, and the outflow of the organic shrinkproof agent as a whole can be suppressed.

In the above aspect of the present invention, the powder resistance ratio R2/R1 between the 1 st carbon material and the 2 nd carbon material contained in the negative electrode plate is controlled to be in the range of 15 to 155, whereby high PSOC life performance can be obtained. This is presumed to be for 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. In addition, the organic shrinkage-preventing agent can be inhibited from flowing out of the negative electrode material during high-temperature cycling, so that the effect of the organic shrinkage-preventing agent can be sufficiently exerted, and the pore structure of the negative electrode material can be maintained. Thus, the formed conductive network is easily maintained even if the PSOC cycle is performed. That is, by combining the 1 st carbon material and the 2 nd carbon material with the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent in the powder resistance ratio as described above, the effect of these organic shrinkproof agents can be improved.

The content of the 1 st organic shrink preventing agent in the negative electrode material is preferably 0.02 to 0.12 mass%. The content of the No. 2 organic shrinkproof agent in the negative electrode material is preferably 0.05 to 0.7 mass%. When the content of each organic shrinkproof agent is in such a range, the effect of improving the PSOC life performance and the low-temperature high-rate performance after high-temperature cycle can be further increased. This is considered to be because the pore structure of the negative electrode material can be maintained by effectively suppressing the shrinkage of the negative electrode material.

The content of the organic shrinkage-preventing agent contained in the negative electrode material is a content in the negative electrode material collected from the lead-acid battery in a fully charged state after the formation by a method described later.

Ratio of specific surface area s2 of the 2 nd carbon material to specific surface area s1 of the 1 st carbon material: s2/s1 is preferably 20 to 240. When the specific surface area ratio s2/s1 is 20 or more, the reduction reaction of lead sulfate is easily performed, and therefore, the reduction of regeneration acceptability can be suppressed while securing high PSOC lifetime performance. When the specific surface area ratio s2/s1 is 240 or less, the specific surface area of each carbon material is in an appropriate range, and adsorption of the organic shrinkproof agent can be further suppressed. As a result, higher low-temperature high-rate performance can be ensured. Further, the increase in the amount of electrolyte reduction after circulation can be reduced, but the detailed reason is not clear.

The average aspect ratio of the 1 st carbon material is preferably 1.5 to 35. In this case, excellent PSOC life performance is easily obtained, and the low-temperature high-power property after high-temperature cycle is easily further improved. 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.

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

A negative electrode plate may be attached with a member such as a pad or a water absorbing paper (blotting 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. Wherein, the thickness of the electrode plate is the thickness containing the pad. When the spacer is attached with the mat, the thickness of the mat is included in the thickness of the spacer.

The negative electrode material 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 metallic lead, but an unformed negative electrode plate is generally produced using lead powder. The negative electrode material contains a carbon material and an organic shrinkproof agent. The negative electrode material may further contain barium sulfate or the like, and may contain other additives as needed.

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.

The method for determining the amount of barium sulfate contained in the negative electrode material is described below. Before quantitative analysis, the lead-acid battery after formation is fully charged and then 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 without pulverization.

The initial sample 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 into lead nitrate. Next, the solution containing lead nitrate was filtered to remove solid components such as carbonaceous materials and barium sulfate.

After the obtained solid component 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 in 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 was put in a crucible together with a membrane filter, and was incinerated at 700 ℃ or higher. The residue remained as barium oxide. The mass (B) of barium sulfate was determined by converting the mass of barium oxide into the mass of barium sulfate.

(organic shrinkproof agent)

In the present embodiment, the organic shrink proofing agent includes a1 st organic shrink proofing agent having an aromatic ring and a2 nd organic shrink proofing agent having an aromatic ring. The content of sulfur element in the No. 1 organic shrink-proof agent is more than 4000 mu mol/g, and the content of sulfur element in the No. 2 organic shrink-proof agent is less than 2000 mu mol/g. Each organic shrink-proof agent is an organic polymer containing sulfur element. Each organic anti-shrink agent may contain 1 aromatic ring in the molecule, but preferably contains a plurality of aromatic rings.

The organic shrinkproof agent preferably contains elemental sulfur as a sulfur-containing group. Among the sulfur-containing groups, sulfonic acid groups or sulfonyl groups in a stable form are preferable. The sulfonic acid group may be present in an acid form or a salt form as in the case of Na salt.

The 1 st organic shrinkproof agent is preferably a synthetic organic shrinkproof agent obtained by synthesis, which is different from lignin. The 1 st organic shrink proofing agent may be used singly or in combination of two or more. The 1 st organic shrink proofing agent is preferably a condensate of an aldehyde compound of a compound having an aromatic ring. Further, a condensate of a polymer (ATBS (registered trademark) polymer) using acrylamide/sodium tert-butyl sulfonate and N, N' - (sulfonyldi-4, 1-phenylene) bis (1,2,3, 4-tetrahydro-6-methyl-2, 4-dioxopyrimidine-5-sulfonamide) may be used as the 1 st organic shrink inhibitor.

The compound having an aromatic ring may have a plurality of aromatic rings. Examples of the aromatic ring include a benzene ring and a naphthalene ring. When the compound having an aromatic ring has a plurality of aromatic rings, the plurality of aromatic rings may be directly bonded or may be linked via a linking group (e.g., alkylene, sulfo, or the like). Examples of such a structure include biphenyl, diphenylalkane, and diphenylsulfone. Examples of the compound having an aromatic ring include compounds having the above aromatic ring and a hydroxyl group, an amino group, and/or a sulfonic acid group. The hydroxyl group, amino group or sulfonic acid group may be bonded directly to the aromatic ring or may be bonded as an alkyl chain having a hydroxyl group, amino group or sulfonic acid group. As the compound having an aromatic ring, a bisphenol compound, a hydroxybiphenyl compound, a hydroxynaphthalene compound, a phenol compound, benzenesulfonic acid, naphthalenesulfonic acid, and the like are preferable. The compound having an aromatic ring may further have a substituent. The organic shrink proofing agent may contain one or more of the residues of these compounds.

Among the compounds having an aromatic ring, bisphenol compounds and naphthalenesulfonic acid are particularly preferable. Examples of the bisphenol compound include "bisphenol a", "bisphenol S", "bisphenol F", "bisphenol AP", "bisphenol AF", "bisphenol B", "bisphenol BP", "bisphenol C", "bisphenol E", "bisphenol G", "bisphenol M", "bisphenol P", "bisphenol PH", "bisphenol TMC" and "bisphenol Z". Wherein "bisphenol S" has a sulfonyl group (-SO)₂-) so that the content of elemental sulfur is easily increased. Since the condensate of a bisphenol compound does not impair the starting performance at low temperatures even when the condensate is exposed to an environment higher than normal temperature, the condensate is suitable for a lead-acid battery placed in an environment higher than normal temperature. Further, the condensate of naphthalenesulfonic acid is less likely to have a smaller polarization than the condensate of bisphenols, and therefore is suitable for a lead-acid battery in which the liquid-reducing property is important

The aldehyde compound condensed with the compound having an aromatic ring is not particularly limited. As the aldehyde compound, for example, in addition to formaldehyde, paraformaldehyde, tris (hydroxymethyl) phosphonium chloride is included

Aldehyde condensates such as alkanes and tetrapolyoxymethylenes. The aldehyde compound may be used singly or in combinationTwo or more. From the viewpoint of high reactivity with a compound having an aromatic ring, formaldehyde is preferable.

The sulfur-containing group may be directly bonded to an aromatic ring contained in the compound, or may be bonded to an aromatic ring as an alkyl chain having a sulfur-containing group, for example. Further, for example, a monocyclic aromatic compound such as aminobenzenesulfonic acid or alkylaminobenzenesulfonic acid may be condensed with the above-mentioned compound having an aromatic ring together with an aldehyde compound. A sulfonic acid group (sulfo group) may be further introduced into a condensation product of a compound having an aromatic ring and an aldehyde compound. The introduction of a sulfonic acid group can increase the sulfur content in the 1 st organic shrinkproof agent. The sulfur element may be contained in the form of a sulfonic acid group or a sulfonyl group.

As the 1 st organic anti-shrinking agent, a formaldehyde condensate of "bisphenol A" into which a sulfonic acid group has been introduced, a formaldehyde condensate of "bisphenol S" into which a sulfonic acid group has been introduced, and a formaldehyde condensate of β -naphthalenesulfonic acid (trade name "DEMOL" of Kao corporation) can be preferably used₂-) sulfur element of structure.

The content of the sulfur element in the 1 st organic shrinkproof agent is preferably 4000. mu. mol/g or more, and from the viewpoint of obtaining higher PSOC life performance, 6000. mu. mol/g or more is preferable. The sulfur content in the 1 st organic shrink preventive is, for example, preferably 9000. mu. mol/g or less, and more preferably 8000. mu. mol/g or less, from the viewpoint of reducing the amount of liquid loss of the electrolyte after the circulation. These lower limit value and upper limit value may be arbitrarily combined. The content of the sulfur element in the 1 st organic shrink-proofing agent can be, for example, 4000 to 9000. mu. mol/g, 4000 to 8000. mu. mol/g, 6000 to 9000. mu. mol/g or 6000 to 8000. mu. mol/g.

The 1 st organic shrink proofing agent has a weight average molecular weight (Mw) of, for example, 4000 or more, preferably 7000 or more. The 1 st organic shrink proofing agent may have a weight average molecular weight of, for example, 100000 or less and 20000 or less.

In the present specification, the weight average molecular weight is a value determined by Gel Permeation Chromatography (GPC). The standard substance used for determining the weight average molecular weight was sodium polystyrene sulfonate.

The weight average molecular weight was measured using the following apparatus under the following conditions.

GPC apparatus: BUILG-UP GPC System SD-8022/DP-8020/AS-8020/CO-8020/UV-8020(TOSOH Co., Ltd.)

Column: TSKgel G4000SWXL, G2000SWXL (7.8mm I.D.. times.30 cm) (manufactured by TOSOH Co., Ltd.)

A detector: UV detector,. lambda.210 nm

Eluent: 1mol/L NaCl: acetonitrile (volume ratio 7: 3)

Flow rate: 1mL/min.

Concentration: 10mg/mL

Injection amount: 10 μ L

Standard substance: polystyrene sodium sulfonate (Mw ═ 275000, 35000, 12500, 7500, 5200, 1680)

As the 1 st organic shrink proofing agent, a shrink proofing agent synthesized by a known method may be used, or a commercially available one may be used. The condensate of a bisphenol compound is obtained, for example, by reacting a bisphenol compound with an aldehyde compound. For example, the organic shrinkproof agent containing a sulfur element can be obtained by carrying out the reaction in the presence of a sulfite or by using a bisphenol compound containing a sulfur element ("bisphenol S" or the like). The content of the sulfur element in the 1 st organic shrinkproof agent can be adjusted by adjusting the amount of the sulfite and/or the amount of the bisphenol compound containing the sulfur element. When other raw materials are used, they can be obtained by the method.

The 2 nd organic shrink-proofing agent may be a synthetic organic shrink-proofing agent obtained by synthesis, or may be a lignin. The synthetic organic shrinkproof agent may be selected from the organic shrinkproof agents described in the 1 st organic shrinkproof agent, except that the content of sulfur element is different. Examples of the lignin include lignin, lignin sulfonic acid, and lignin derivatives such as salts thereof (alkali metal salts such as sodium salts).

The content of sulfur in the No. 2 organic anti-shrinkage agent may be 2000. mu. mol/g or less, and from the viewpoint of increasing the effect of suppressing the liquid loss after the cycle, it is preferably 1000. mu. mol/g or less, and more preferably 800. mu. mol/g or less. The lower limit of the sulfur element content in the No. 2 organic shrinkproof agent is not particularly limited, but is preferably 400. mu. mol/g or more from the viewpoint of increasing the effect of improving the PSOC life performance.

The weight average molecular weight (Mw) of the No. 2 organic shrink-proofing agent is, for example, 3000 to 20000, preferably 4000 to 10000, and may be 4000 or more and less than 7000.

From the viewpoint of obtaining a higher PSOC life, the content of the 1 st organic shrink inhibitor in the negative electrode material is preferably 0.02 mass% or more. From the viewpoint of further improving the low-temperature high-rate performance after high-temperature cycles, the content of the 1 st organic shrink preventing agent in the negative electrode material is preferably 0.05% by mass or more, and more preferably 0.08% by mass or more. The content of the 1 st organic shrink preventing agent in the negative electrode material is, for example, 0.12% by mass or less, and preferably 0.10% by mass or less from the viewpoint of increasing the effect of reducing the liquid-off amount after the cycle. These lower limit value and upper limit value may be arbitrarily combined. The content of the 1 st organic shrink preventing agent in the negative electrode material may be, for example, 0.02 to 0.12% by mass, 0.05 to 0.12% by mass, or 0.08 to 0.12% by mass, and in these ranges, the upper limit value may be set to 0.10% by mass or less in order to reduce the amount of liquid reduction after the cycle.

The content of the 2 nd organic shrink preventing agent in the negative electrode material may be 0.02 mass% or more, and is preferably 0.05 mass% or more from the viewpoint of further increasing the effect of improving the PSOC lifetime performance. The content of the 2 nd organic shrink preventing agent in the negative electrode material is, for example, 0.7% by mass or less, and is preferably 0.5% by mass or less, and more preferably 0.3% by mass or less, from the viewpoint of easily obtaining excellent regeneration acceptability. These lower limit value and upper limit value may be arbitrarily combined. The content of the 2 nd organic shrink preventing agent in the negative electrode material may be, for example, 0.02 to 0.7% by mass, 0.02 to 0.5% by mass, 0.02 to 0.3% by mass, 0.05 to 0.7% by mass, 0.05 to 0.5% by mass, or 0.05 to 0.3% by mass.

By adjusting the content of the 1 st organic shrinkproof agent and the content of the 2 nd organic shrinkproof agent in the anode electrode material as described above, the improvement effect of PSOC life performance and low-temperature high-rate performance after high-temperature cycle can be further increased.

In the organic shrink-proofing agent contained in the negative electrode material, the total amount of the 1 st organic shrink-proofing agent and the 2 nd organic shrink-proofing agent is preferably 90 mass% or more, and more preferably 95 mass% or more.

The method of analyzing the organic shrinkproof agent and the method of determining the physical properties will be described below.

(A) Analysis of organic shrink-proofing Agents

(A-1) specifying the kind of organic shrinkproof agent

The kind of the organic shrinkproof agent in the negative electrode material was specified as follows.

The fully charged lead-acid battery was decomposed, and the negative electrode plate was taken out, washed with water to remove the sulfuric acid component, and vacuum-dried (dried under a pressure lower than atmospheric pressure). The negative electrode material containing the active material was separated from the negative electrode plate, and the negative electrode material was immersed in a 1mol/L aqueous NaOH solution to extract the organic anti-shrinkage agent. Then, the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent are separated from the extract. The insoluble components were removed from the separated products containing the respective organic shrinkproof agents by filtration, and the obtained solutions were desalted, concentrated and freeze-dried (lyophilized) to obtain powder samples. Desalting column and ion exchange membrane are used for desalting. The kind of the organic shrinkproof agent is determined from information obtained from an infrared spectrum and an NMR spectrum measured from a powder sample using the organic shrinkproof agent thus obtained, and an ultraviolet-visible absorption spectrum obtained by diluting the powder sample with distilled water and measuring the diluted powder sample with an ultraviolet-visible absorption spectrometer.

The step of separating the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent from the extract is performed as follows. First, the presence or absence of various organic shrinkproof agents is judged by measuring the above extract by infrared spectroscopy, NMR and/or GC-MS. Next, molecular weight distribution was measured by GPC analysis of the above extract, and if a plurality of organic shrink inhibitors could be separated by molecular weight, the organic shrink inhibitors were separated by column chromatography based on the difference in molecular weight. When it is difficult to perform separation by utilizing the difference in molecular weight, one of the organic shrinkproof agents is separated by a precipitation separation method based on the difference in solubility due to the difference in the kind of functional group and/or the amount of functional group of the organic shrinkproof agent. Specifically, an aqueous sulfuric acid solution was added dropwise to a mixture obtained by dissolving the above extract in an aqueous NaOH solution, and the pH of the mixture was adjusted to coagulate and separate one of the organic shrinkproof agents. Insoluble components were removed from the solution obtained by redissolving the separated product in an aqueous NaOH solution by filtration as described above. In addition, the remaining solution after the separation of one organic shrinkproof agent was concentrated. The resulting concentrate contains the other organic shrink proofing agent and insoluble components are removed from the concentrate by filtration as described above.

In the present specification, in the case of a liquid battery, the fully charged state of a lead acid battery is a state in which the lead acid battery is subjected to constant current charging at a current of 0.2CA in a 25 ℃ water tank until the battery reaches 2.5V/Cell, and then is subjected to constant current charging at 0.2CA for 2 hours. In the case of a valve-regulated battery, the fully charged state is a state in which constant-current constant-voltage charging of 2.23V/Cell is performed at 0.2CA in a gas tank at 25 ℃, and the charging is terminated when the charging current in constant-voltage charging becomes 1mCA or less.

In the present specification, 1CA means a current value (a) having the same value as the nominal capacity (Ah) of the battery. For example, if the battery is a battery with a nominal capacity of 30Ah, 1CA is 30A and 1mCA is 30 mA.

(A-2) measurement of content of organic shrinkproof agent

The content of the organic shrinkproof agent in the negative electrode material was measured as follows.

The same procedure as in (A-1) was carried out to obtain solutions in which insoluble components were removed from the separated products containing the respective organic shrinkproofing agents by filtration. The ultraviolet-visible absorption spectrum of each solution obtained was measured. Then, based on the ultraviolet-visible absorption spectrum, the content of the 1 st organic shrinkproof agent and the content of the 2 nd organic shrinkproof agent in the negative electrode material were measured using calibration curves prepared in advance.

When a battery manufactured by another company is obtained and the content of the synthetic shrinkproof agent is measured, since the structural formula of the organic shrinkproof agent cannot be specified precisely, in the case where the same organic shrinkproof agent cannot be used as a calibration curve, the content of each organic shrinkproof agent is measured by using an ultraviolet-visible absorption spectrum, an infrared spectrum, an NMR spectrum, or the like, which shows a shape similar to that of the organic shrinkproof agent extracted from the negative electrode of the battery and can be obtained by another route to prepare a calibration curve.

(A-3) measurement of elemental Sulfur content in organic shrinkproof agent

0.1g of each of the powder samples of the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent separated in the same manner as in the above (A-1) was taken to obtain an eluent obtained by converting the S element in the powder samples into sulfuric acid by the oxygen bottle combustion method. Then, the eluate was titrated with barium perchlorate using a thorium reagent as an indicator to determine the sulfur content in 0.1g of the powder sample. The sulfur content was converted to an amount of 1g per unit, and used as the sulfur content in each organic shrinkproof agent.

(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 of artificial graphite and natural graphite as long as it is a carbon material having a graphite-type crystal structure.

In addition, in the 1 st carbon material, 1300cm in Raman spectrum^-1～1350cm^-1Peak (D band) in the range of (1) and at 1550cm^-1～1600cm^-1Intensity ratio I of the peak (G band) appearing in the range of (1)_D/I_GThe carbon material of 0 to 0.9 is called graphite.

Regarding the 1 st carbon material and the 2 nd carbon material, the ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material may be: the ratio R2/R1 is 15 to 155, and the type, specific surface area and/or aspect ratio of the carbon material used for the preparation of the negative electrode material are selected or adjusted. In addition to these elements, the particle size of the carbon material to be used may be further adjusted. By selecting or adjusting these elements, the powder resistance of each of the carbon materials 1 st and 2 nd carbon materials can be adjusted, and as a result, the powder resistance ratio R2/R1 can be adjusted.

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

The ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material (powder resistance ratio R2/R1) may be 15 to 155. From the viewpoint of further improving the low-temperature high-rate performance after high-temperature cycles, the powder resistance ratio R2/R1 is preferably 30 or more, and may be 50 or more. From the same viewpoint, it is also preferable that the powder resistance ratio R2/R1 is 130 or less. These lower limit value and upper limit value may be arbitrarily combined. The powder resistance ratio R2/R1 may be 30-155, 30-130, 50-155, 50-130 or 15-130. When the powder resistance ratio R2/R1 is in such a range, excellent PSOC life performance can be ensured.

Ratio of specific surface area s2 of the 2 nd carbon material to specific surface area s1 of the 1 st carbon material: s2/s1 is, for example, 10 or more and 500 or less. From the viewpoint of ensuring high low-temperature high-rate performance and high PSOC life performance after high-temperature cycling, and suppressing a decrease in regeneration acceptability and a significant increase in the amount of liquid to be reduced after cycling, the specific surface area ratio s2/s1 is preferably 20 or more and 240 or less. From the viewpoint of obtaining higher regeneration acceptability, the specific surface area ratio s2/s1 is preferably 30 or more, and may be 40 or more. From the viewpoint of further improving the low-temperature high-rate performance after high-temperature cycle and reducing the amount of liquid reduction after cycle, the specific surface area ratio s2/s1 is preferably 240 or less, and more preferably 120 or less. These lower limit value and upper limit value may be arbitrarily combined. The specific surface area ratio s2/s1 may be, for example, 30 to 500, 30 to 400, 30 to 240, 30 to 120, 40 to 500, 40 to 400, 40 to 240, 40 to 120, 10 to 240, 20 to 240, 10 to 120, or 20 to 120.

The average aspect ratio of the 1 st carbon material is, for example, 1 or more and 200 or less. The average aspect ratio of the 1 st carbon material is preferably 1.5 to 100 from the viewpoint of easily ensuring high PSOC lifetime performance. The carbon material 1 preferably has an average aspect ratio of 1.5 to 35, and may be 5 to 35 or 5 to 30, from the viewpoint of easily ensuring high-temperature cycle performance at low temperature and high rate. When the average aspect ratio of the 1 st carbon material is 1.5 or more, a conductive network is easily formed in the negative electrode material, and the effect of improving the PSOC lifetime performance can be further increased. 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 electrode plate can be suppressed, and high PSOC life performance is easily ensured.

The content of the 1 st carbon material in the negative electrode material is, for example, 0.05 to 3.0% by mass, preferably 0.1 to 2.0% by mass, and more preferably 0.1 to 1.5% by mass. When the content of the 1 st carbon 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 is 3.0 mass% or less, the adhesion between the active material particles is easily ensured, so that 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 1.0 mass%, preferably 0.05 to 0.5 mass%, and more preferably 0.05 to 0.3 mass%. When the content of the 2 nd carbon material is 0.03 mass% or more, the effect of improving the PSOC lifetime performance can be further increased. When the content of the 2 nd carbon material is 1.0 mass% or less, adsorption of the organic shrinkproof agent can be further suppressed, and the low-temperature high-rate performance can be further improved.

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

The fully charged lead-acid battery thus formed is decomposed, and the negative electrode plate is taken out, washed with water to remove sulfuric acid, and vacuum-dried (dried under a pressure lower than atmospheric pressure). 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 ℃. To the mixture were further added 10g of disodium ethylenediaminetetraacetate, 30mL of 28 mass% aqueous ammonia and 100mL of water, and heating was continued to dissolve the 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 for 5 minutes to perform sieving while dispersing ion-exchanged water. The carbon material 1 left on the screen was collected from the screen by passing ion-exchanged water therethrough, and separated from the ion-exchanged water by filtration. The 2 nd carbon material having passed through the screen was collected 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 are values measured by: for each of the carbon material 1 and the carbon material 2 separated in the above-described step (B-1), 0.5g of a sample was put into a powder resistance measurement system (MCP-PD 51, manufactured by Mitsubishi Chemical Analytech corporation) and the mixture was subjected to a pressure of 3.18MPa using a pressure based on 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 area s1 of the 1 st carbon material and the specific surface area s2 of 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 respective 1 st carbon material and 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 by the following apparatus under the following conditions.

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: based on 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 10 or more particles were 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 orthogonal to the maximum particle diameter d1, and the d1 was divided by d2 to determine the aspect ratio of each particle. The average aspect ratio was calculated by averaging the obtained aspect ratios.

(others)

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

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 a negative electrode current collector with a negative electrode paste, aging and drying the negative electrode paste to produce an unformed negative electrode plate, and then forming the unformed negative electrode plate into a negative electrode. The negative electrode paste is prepared by adding water and sulfuric acid to lead powder, an organic shrinkproof agent, a carbon material, and, if necessary, various additives, and kneading them. In the aging, the non-formed negative electrode plate is preferably aged at a temperature higher than room temperature and at a high humidity.

The formation of the negative electrode plate can be performed by charging an electrode plate group including an unformed negative electrode plate in a state where the electrode plate group is immersed in an electrolyte containing sulfuric acid in a battery case of a lead-acid battery. The formation may be performed before the lead-acid battery or the electrode plate group is assembled. The metallic lead is formed into a sponge.

(Positive plate)

The positive plate of the lead storage battery has a pasted type and a clad 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 connected to the core rod, a positive electrode material filled into the tubes into which the core rod is inserted, and a connection base 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.

As the lead alloy used for the positive electrode current collector, a Pb — Ca alloy, a Pb — Sb alloy, and a Pb — Ca — Sn alloy are preferable from the viewpoint 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.

The positive electrode material contains a positive 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.

In the case of the negative electrode plate, the unformed pasted positive electrode plate can be obtained by filling the positive electrode current collector with the positive electrode paste, aging, and drying. The positive electrode paste is prepared by kneading lead powder, an additive, water, and sulfuric acid.

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

And (4) forming the formed unformed positive plate. Lead dioxide is generated through chemical conversion. The formation of the positive electrode plate may be performed before the assembly of the lead-acid battery or the electrode plate group.

(spacer)

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

The nonwoven fabric is a mat formed by winding fibers without weaving, and mainly includes 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 components 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 embedded therein, or the like, as required.

(electrolyte)

The electrolyte is an aqueous solution containing sulfuric acid, and can be gelled as necessary. The specific gravity of the electrolyte in the fully charged lead-acid battery after formation at 20 ℃ is, for example, 1.10g/cm³～1.35g/cm³Preferably 1.20g/cm³～1.35g/cm³。

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 divided into a plurality of battery cell chambers 14 by partitions 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 replenished, the liquid port plug 18 is opened to replenish the replenishing 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 is 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 a battery cell chamber 14 located at one end of the battery case 12, a negative electrode housing portion 6 in which the lug portions 2a of the plurality of negative electrode plates 2 are connected in parallel is connected to the penetration connector 8, and a positive electrode housing portion 5 in which the lug portions 3a of the plurality of positive electrode plates 3 are connected in parallel is connected to the positive electrode post 7. The positive post 7 is connected to a positive terminal 17 on the outside of the cover 15. In the battery cell chamber 14 located at the other end of the battery container 12, the negative electrode housing portion 6 is connected to the negative electrode post 9, and the positive electrode housing portion 5 is connected to the penetration connector 8. The negative electrode tab 9 is connected to a negative electrode terminal 16 on the outside of the cover 15. Each of the through-connectors 8 connects the electrode groups 11 of the adjacent battery cell chambers 14 in series through-holes provided in the partition walls 13.

The 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 in which,

the lead storage battery comprises a negative electrode plate, a positive electrode plate and an electrolyte,

the negative electrode plate contains a negative electrode material containing a carbon material and an organic shrinkproof agent,

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 organic shrink-proofing agent comprises a1 st organic shrink-proofing agent having an aromatic ring and having a sulfur element content of 4000 mu mol/g or more and a2 nd organic shrink-proofing agent having an aromatic ring and having a sulfur element content of 2000 mu mol/g or less.

(2) In the above (1), the content of the 1 st organic shrink preventing agent in the negative electrode material is preferably 0.02 to 0.12 mass%, and the content of the 2 nd organic shrink preventing agent is preferably 0.05 to 0.7 mass%.

(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 20 to 240.

(4) In any one of the above (1) to (3), the 1 st carbon material preferably has an average aspect ratio of 1.5 to 35.

(5) In any of the above (1) to (4), the content of the sulfur element in the 1 st organic anti-shrinkage agent is preferably 9000. mu. mol/g or less.

(6) In any of the above (1) to (5), the content of the sulfur element in the 1 st organic shrinkproof agent is preferably 6000. mu. mol/g or more.

(7) In any of the above (1) to (6), the content of sulfur element in the 2 nd organic shrinkproof agent is preferably 1000. mu. mol/g or less.

(8) In any of the above (1) to (7), the content of sulfur element in the 2 nd organic shrinkproof agent is preferably 400. mu. mol/g or more.

(9) In any one of the above (1) to (8), the content of the 1 st organic shrink preventing agent in the negative electrode material is preferably 0.05% by mass or more.

(10) In any one of the above (1) to (9), the content of the 1 st organic shrink preventing agent in the negative electrode material is preferably 0.10% by mass or less.

(11) In any one of the above (1) to (10), the content of the 2 nd organic shrink preventing agent in the negative electrode material is preferably 0.5% by mass or less.

(12) In any one of the above (1) to (11), the content of the 1 st carbon material in the negative electrode material is preferably 0.05% by mass or more.

(13) In any one of the above (1) to (12), the content of the 1 st carbon material in the negative electrode material is preferably 3.0% by mass or less.

(14) In any one of the above (1) to (13), the content of the 2 nd carbon material in the negative electrode material is preferably 0.03 mass% or more.

(15) In any one of the above (1) to (14), the content of the 2 nd carbon material in the negative electrode material is preferably 1.0 mass% or less.

(16) In any one of the above (1) to (15), the ratio: R2/R1 is preferably 30 or more.

(17) In any one of the above (1) to (16), the ratio: R2/R1 are preferably 130 or less.

(18) In any one of the above (1) to (17), the ratio: s2/s1 is preferably 30 or more.

(19) In any one of the above (1) to (18), the ratio: s2/s1 is preferably 120 or less.

(20) In any one of the above (1) to (19), the 1 st carbon material preferably has an average aspect ratio of 5 or more.

(21) In any one of the above (1) to (20), the 1 st carbon material preferably has an average aspect ratio of 30 or less.

(22) In any one of the above (1) to (21), it is preferable that the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

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.

Lead accumulator A1

(1) Production of negative electrode plate

Lead powder, water, dilute sulfuric acid, barium sulfate, a carbon material, a formaldehyde condensate of a bisphenol compound having a sulfonic acid group introduced thereto (1 st organic shrinkproof agent, sulfur content: 6000 μmol/g, Mw: 7500), and lignin (2 nd organic shrinkproof agent, sulfur content: 600 μmol/g, Mw: 5500) were mixed to obtain a negative electrode paste. The negative electrode paste was filled into the mesh part of a expanded grid made of a Pb-Ca-Sn alloy, and the mixture was aged and dried to obtain an unformed negative electrode plate. Carbon black (average particle diameter D) was used as the carbon material₅₀: 40nm) and graphite (average particle diameter D)₅₀：110μm)。

The sulfur content (μmol/g) in each organic shrinkproof agent was substantially not different from the value measured by extracting each organic shrinkproof agent from a lead-acid battery after disassembling the negative electrode material. Therefore, the values obtained for the respective organic shrinkproofing agents before the preparation of the negative electrode material are described below as the sulfur element content in the respective organic shrinkproofing agents described for the respective batteries.

The amount of the 1 st organic shrink preventing agent contained in 100 mass% of the fully charged negative electrode material after formation was adjusted to 0.05 mass% and the amount of the 2 nd organic shrink preventing agent was adjusted to 0.1 mass%, and the organic shrink preventing agents were mixed in the negative electrode paste.

(2) Production of Positive plate

The lead powder, water and sulfuric acid were mixed to prepare a positive electrode paste. The positive electrode paste was filled into the mesh part of a seine grid made of a Pb-Ca-Sn alloy, and the mixture was cured and dried to obtain an unformed positive electrode plate.

(3) Production of lead-acid battery

The unformed negative electrode plate was housed in a bag-like separator formed of a microporous film made of polyethylene, and an electrode group was formed from unformed negative electrode plate 5 pieces and unformed positive electrode plate 4 pieces in each cell.

The electrode plate group was inserted into a cell container made of polypropylene, and an electrolyte was injected into the cell container to carry out formation, thereby assembling a flooded lead acid battery a1 having a nominal voltage of 12V and a nominal capacity of 30Ah (5 hours rate).

The content (c1 (mass%) of each organic shrinkproof agent contained in the negative electrode material (100 mass%) extracted from the negative electrode plate was determined in accordance with the above procedure for 1 lead-acid battery produced. The content of each organic shrinkproof agent determined in this way is a value slightly different from the content (c2 (mass%) of each organic shrinkproof agent in the negative electrode material (100 mass%) prepared at the time of manufacturing a lead-acid battery. Therefore, a ratio R (c 1/c2) between the contents c1 and c2 is determined in advance, and the content c2 of each organic shrink-proofing agent is adjusted so that the content c1 of each organic shrink-proofing agent becomes a predetermined value by the ratio R. For each battery, the ratio R was determined for the sulfur element content of each organic shrink-proofing agent used, and the content c2 of the organic shrink-proofing agent was adjusted based on the determined ratio R for the negative electrode material using the organic shrink-proofing agent having the same sulfur element content.

In the lead-acid battery, the content of the 1 st carbon material was set to 1.0 mass%, and the content of the 2 nd carbon material was set to 0.5 mass%. The powder resistance ratio R2/R1 was set to 15. The average aspect ratio of the 1 st carbon material was 1.5. These values are values obtained by: when the negative electrode plate of the manufactured lead-acid battery was taken out and the carbon material contained in the negative electrode material was separated into the 1 st carbon material and the 2 nd carbon material according to the above-described procedure, the values were obtained as the contents of the respective carbon materials contained in the negative electrode material (100 mass%). The powder resistances R1 and R2, the powder resistance ratio R2/R1, and the average aspect ratio of the 1 st carbon material of each carbon material were also determined from the lead-acid battery after production according to the procedures described above.

Lead accumulator A2-A9

By adjusting the average particle diameter D of each carbon material used₅₀The specific surface area and the average aspect ratio of the 1 st carbon material were changed as shown in Table 2, based on the powder resistance ratio R2/R1. Except for this, a negative electrode plate was produced in the same manner as in lead storage battery A1 except thatLead acid batteries a2 to a9 were assembled in the same manner as the lead acid battery a1 except for the obtained negative electrode plate.

Lead accumulator B1-B9

The amount of the 1 st organic shrink-proofing agent added was adjusted so that the content of the 1 st organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became 0.1 mass%, and the resultant was mixed in the negative electrode paste. Except for this, the negative electrode plate was formed in the same manner as in the lead storage batteries a1 to a 9. Lead acid batteries B1 to B9 were assembled in the same manner as lead acid battery a1 except that the obtained negative electrode plate was used.

Lead accumulator C1-C9

The amount of the sulfonic acid group introduced into the formaldehyde condensate of a bisphenol compound was adjusted so that the sulfur content of the 1 st organic shrinkproof agent became 4000. mu. mol/g. A negative electrode plate was formed in the same manner as in lead storage batteries B1 to B9, except that the organic shrinkproof agent (Mw 9500) having a sulfur element content of 4000 μmol/g was used. A lead acid battery was assembled in the same manner as the lead acid battery a1, except that the obtained negative electrode plate was used.

Lead storage batteries D1-D9

The amount of the sulfonic acid group introduced into the formaldehyde condensate of a bisphenol compound was adjusted so that the sulfur content of the 1 st organic anti-shrinkage agent was 8000. mu. mol/g. A negative electrode plate was formed in the same manner as in lead storage batteries B1 to B9, except that the organic shrinkproof agent (Mw 9500) having a sulfur element content of 8000 μmol/g was used. Lead storage batteries D1 to D9 were assembled in the same manner as lead storage battery a1, except that the obtained negative electrode plate was used.

Lead accumulator E1-E9

The amount of the 2 nd organic shrinkage inhibitor added was adjusted so that the content of the 2 nd organic shrinkage inhibitor contained in 100 mass% of the fully charged negative electrode material after formation became 0.5 mass%, and the organic shrinkage inhibitor was added to the negative electrode paste. Except for this, the negative electrode plate is formed in the same manner as in the lead storage batteries B1 to B9. Lead acid batteries E1 to E9 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used.

Lead accumulator Z1

As the carbon material, only carbon black (average particle diameter D) was used₅₀: 40nm), and as the organic shrinkproof agent, only lignin (No. 2 organic shrinkproof agent, sulfur element content: 600 μmol/g, Mw 5500). In the lead-acid battery, the content of the 2 nd carbon material was set to 0.3 mass%. Except for these, the negative electrode plate was formed in the same manner as in the lead storage battery a 1. A lead acid battery Z1 was assembled in the same manner as the lead acid battery a1, except that the obtained negative electrode plate was used.

Lead accumulator Z2

A negative electrode plate was formed in the same manner as in lead storage battery Z1, except that the content of the 2 nd carbon material was 1.5 mass%. A lead acid battery Z2 was assembled in the same manner as the lead acid battery a1, except that the obtained negative electrode plate was used.

Lead accumulator Z3 and Z4

The amount of the 2 nd organic anti-shrinkage agent added was adjusted so that the content of the 2 nd organic anti-shrinkage agent contained in 100 mass% of the fully charged negative electrode material after formation became 0.5 mass% (lead acid battery Z3) and 0.8 mass% (lead acid battery Z4), respectively, and the adjusted organic anti-shrinkage agent was added to the negative electrode paste. Except for this, the negative electrode plate was formed in the same manner as in lead storage battery Z2. Lead acid batteries Z3 and Z4 were each assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used.

Lead accumulator Z5-Z7

As the carbon material, only carbon black (average particle diameter D) was used₅₀: 40nm) and as the organic shrinkproof agent, only a formaldehyde condensate of a bisphenol compound having a sulfonic acid group introduced thereto (No. 1 organic shrinkproof agent, sulfur element content: 6000 μmol/g, Mw 9500). In the lead-acid battery, the content of the 2 nd carbon material was 1.5% by mass. The 1 st organic anti-shrinkage agent was added to the negative electrode paste in such an amount that the content of the 1 st organic anti-shrinkage agent contained in 100 mass% of the fully charged negative electrode material after formation became 0.05 mass% (lead acid battery Z5), 0.1 mass% (lead acid battery Z6), and 0.12 mass% (lead acid battery Z7), respectively. Except for these, the negative electrode plate was formed in the same manner as in the lead storage battery a 1. Lead acid batteries Z5 to Z7 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used.

Lead accumulator Z8

As the carbon material, only carbon black (average particle diameter D) was used₅₀: 40 nm). In this embodiment, the content of the 2 nd carbon material is 1.5% by mass. Except for these, a negative electrode plate was formed in the same manner as in lead storage battery B1. A lead acid battery Z8 was assembled in the same manner as the lead acid battery a1, except that the obtained negative electrode plate was used.

[ evaluation 1: PSOC lifetime Performance and post-cycle fluid loss

Charging and discharging were performed in the mode shown in table 1. The number of cycles at which the terminal voltage reaches 1.2V per unit cell was taken as an indicator of PSOC life performance. The results of the lead-acid battery Z1 were expressed as a ratio of 100.

[ Table 1]

Constant current discharge (CC discharge)

CV charging, constant voltage charging

The mass of the lead-acid battery after evaluation of the PSOC life performance was measured, and the mass was subtracted from the mass before evaluation to determine the amount of electrolyte reduction after the circulation. The liquid-reduced amount in the lead-acid battery Z1 was expressed by a ratio of 100.

[ evaluation 2: low temperature high rate Performance after high temperature cycling ]

In JIS D5301: under the conditions of the light load life test specified in 2006, 480 cycles of charge and discharge were performed. In the light load life test, specifically, constant current discharge was performed at 25A for 240 seconds in a water tank at 40 ℃, and constant voltage charge was performed at 2.47V per unit cell and at a maximum current of 25A for 600 seconds. Next, by JIS D5301: the discharge current (150A) defined in 2006 was discharged at-15 ℃ until the terminal voltage reached 1V per unit cell, and the discharge time at that time was determined. The discharge time was used as an index of low-temperature high-rate performance after high-temperature cycle. The results of the lead-acid battery Z1 were expressed as a ratio of 100.

[ evaluation 3: acceptability for regeneration)

After discharging only 10% of the nominal capacity at 0.2CA at 25 ℃, the fully charged lead-acid battery was left at room temperature for 12 hours. Then, constant voltage charging was performed at 2.42V per unit cell, and the electric energy in the first 10 seconds at this time was obtained as an index for evaluating the regeneration acceptability. The results of the lead-acid battery Z1 were expressed as a ratio of 100.

The results of the lead-acid batteries a1 to a9, B1 to B9, C1 to C9, D1 to D9, E1 to E9, and Z1 to Z8 are shown in table 2.

[ Table 2]

As shown in table 2, even when the 1 st organic anti-shrinkage agent and the 2 nd organic anti-shrinkage agent were used in combination in the lead-acid battery using only the 2 nd carbon material, the effect of improving the low-temperature high-rate performance after the high-temperature cycle was low (Z1). This is because the adsorption of the 2 nd organic shrinkproof agent to the 2 nd carbon material becomes remarkable. On the other hand, when the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent are used in combination and the 1 st carbon material and the 2 nd carbon material are combined, adsorption of the 2 nd organic shrinkproof agent to the 2 nd carbon material is suppressed, whereby low-temperature high-rate performance after high-temperature cycles is improved (a1 to a9, B1 to B9, C1 to C9, D1 to D9, and E2 to E9). In addition, in the lead-acid battery having an R2/R1 ratio in the range of 15 to 155, a conductive network is easily formed in the negative electrode material, and the effect of the organic anti-shrinkage agent is sufficiently exerted, and the conductive network can be maintained, so that high PSOC life performance can be ensured (a1 to a7, B1 to B7, C1 to C7, D1 to D7, and E2 to E7).

Lead storage battery F1-F5

The amount of the sulfonic acid group introduced into the formaldehyde condensate of a bisphenol compound was adjusted so that the sulfur content of the 1 st organic shrinkproof agent became the value shown in Table 3. A negative electrode plate was formed in the same manner as in lead storage battery a1, except that the obtained 1 st organic shrinkproof agent was used. Lead acid batteries F1 to F5 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. Lead acid battery F2 using the 1 st organic shrinkproof agent having a sulfur element content of 6000. mu. mol/g was the same as lead acid battery A1. The Mw of the 1 st organic shrinkproof agent was 9500.

Lead accumulator G1-G5

The amount of the 1 st organic shrink-proofing agent added was adjusted so that the content of the 1 st organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became 0.1 mass%, and the 1 st organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate is formed in the same manner as in the lead storage batteries F1 to F5. Lead acid batteries G1 to G5 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. The lead acid battery G2 using the 1 st organic shrinkproof agent having a sulfur element content of 6000. mu. mol/G was the same as the lead acid battery B1.

Lead accumulator H1-H5

The amount of the sulfonic acid group introduced into the formaldehyde condensate of a bisphenol compound was adjusted so that the sulfur content of the 1 st organic shrinkproof agent became a value shown in Table 3. A negative electrode plate was formed in the same manner as in lead storage battery a7, except that the obtained 1 st organic shrinkproof agent was used. Lead acid batteries H1 to H5 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. The lead secondary battery H2 using the 1 st organic shrinkproof agent having a sulfur element content of 6000. mu. mol/g was the same as the lead secondary battery A7.

Lead accumulator J1-J5

The amount of the 1 st organic shrink-proofing agent added was adjusted so that the content of the 1 st organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became 0.1 mass%, and the 1 st organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate is formed in the same manner as in the lead storage batteries H1 to H5. Lead acid batteries J1 to J5 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. Lead acid battery J2 using the 1 st organic shrinkproof agent having a sulfur element content of 6000. mu. mol/g was the same as lead acid battery B7.

Similar to the lead acid battery a1, the lead acid batteries F1 to F5, G1 to G5, H1 to H5, and J1 to J5 were evaluated 1 to 3. The evaluation results are shown in table 3.

[ Table 3]

As shown in Table 3, when the organic shrinkproof agent having a sulfur element content of 3000. mu. mol/G was used in combination with the No. 2 organic shrinkproof agent, the effect of improving the low-temperature high-rate performance after high-temperature cycles was reduced (F5, G5, H5, J5). This is presumably because the organic shrinkproof agent having a sulfur element content of 3000. mu. mol/g is likely to flow out during high-temperature cycles, and it is difficult to maintain the pore structure of the negative electrode material. On the other hand, when the 1 st organic shrinkproof agent and the 2 nd organic shrinkproof agent having a sulfur element content of 4000. mu. mol/G or more are used in combination, high PSOC life performance can be secured, and high low-temperature high-rate performance after high-temperature cycle can be obtained (F1 to F4, G1 to G4, H1 to H4, J1 to J4). The reason why high low-temperature high-rate performance is obtained is considered to be that the use of the 1 st organic shrink preventing agent suppresses the outflow of the organic shrink preventing agent during high-temperature cycles, and ensures the pore structure of the negative electrode material.

Lead accumulator K1-K6

The amount of the 1 st organic shrink-proofing agent added was adjusted so that the content of the 1 st organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became the value shown in table 4, and the organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate was formed in the same manner as in lead storage battery a 1. Lead acid batteries K1 to K6 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. Lead acid battery K2 containing 0.05 mass% of the No. 1 organic shrinkproof agent was the same as lead acid battery A1.

Lead accumulator L1-L6

The amount of the 1 st organic shrink-proofing agent added was adjusted so that the content of the 1 st organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became the value shown in table 4, and the organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate was formed in the same manner as in lead storage battery a 7. Lead acid batteries L1 to L6 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. Lead acid battery L2 having a content of the 1 st organic shrinkproof agent of 0.05 mass% was the same as lead acid battery A7.

Lead storage battery M1-M7

The amount of the 2 nd organic shrink-proofing agent added was adjusted so that the content of the 2 nd organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became the value shown in table 4, and the adjusted organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate was formed in the same manner as in lead storage battery a 7. Lead storage batteries M1 to M7 were assembled in the same manner as the lead storage battery a1, except that the obtained negative electrode plate was used. The lead acid battery M3 having a content of the No. 2 organic shrinkproof agent of 0.1 mass% was the same as the lead acid battery A7.

Lead accumulator N1-N7

The amount of the 2 nd organic shrink-proofing agent added was adjusted so that the content of the 2 nd organic shrink-proofing agent contained in 100 mass% of the fully charged negative electrode material after formation became the value shown in table 4, and the adjusted organic shrink-proofing agent was added to the negative electrode paste. Except for this, the negative electrode plate is formed in the same manner as in lead storage battery B7. Lead acid batteries N1 to N7 were assembled in the same manner as lead acid battery a1, except that the obtained negative electrode plate was used. Lead acid battery N3 containing 0.1 mass% of the No. 2 organic shrinkproof agent was the same as lead acid battery B7.

Similar to lead storage battery a1, evaluation 1 to evaluation 3 were performed for lead storage batteries K1 to K6, L1 to L6, M1 to M7, and N1 to N7. The evaluation results are shown in table 4.

[ Table 4]

As shown in Table 4, when the content of the 1 st organic anti-shrinking agent is 0.02 mass% or more, a high PSOC life (K1-K5, L1-L5) can be obtained. When the content of the No. 2 organic shrink-proofing agent is 0.02 mass% or more, a high PSOC life (M1-M6, N1-N6) can be obtained. In these cases, it is presumed that the effect of suppressing shrinkage of the negative electrode material is enhanced, and the pore structure of the negative electrode material is maintained.

When the content of the 1 st organic anti-shrinking agent is 0.05 mass% or more or 0.08 mass% or more, the low-temperature high-rate performance after high-temperature cycles is further improved (K2 to K5, L2 to L5). When the content of the 2 nd organic shrink proofing agent is 0.05 mass% or more, the PSOC life performance and the low-temperature high-rate performance after high-temperature cycle (M2 to M6, N2 to N6) can be further ensured. This is because the fine structure in the pore structure of the negative electrode material can be sufficiently maintained even in these cases. When the content of the 1 st organic shrinkproof agent is 0.10% by mass or less, the effect of reducing the amount of liquid to be reduced after the circulation is high (K1 to K4, K6, L1 to L4, and L6). When the content of the 2 nd organic shrinkproof agent is 0.5% by mass or less or 0.3% by mass or less, excellent regeneration acceptability can be obtained (M1 to M5, M7, N1 to N5, N7).

Lead accumulator O1-O7

The specific surface area ratio s2/s1 obtained in accordance with the above procedure was adjusted to the value shown in table 5 by adjusting the specific surface area of each carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery a7, and lead storage batteries O1 to O7 were assembled in the same manner as in lead storage battery a1, except that the obtained negative electrode plates were used.

Lead accumulator P1-P7

The specific surface area ratio s2/s1 obtained in accordance with the above procedure was adjusted to the value shown in table 5 by adjusting the specific surface area of each carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery B7, and lead storage batteries P1 to P7 were assembled in the same manner as in lead storage battery a1, except that the obtained negative electrode plates were used. The lead secondary battery P3 having a specific surface area ratio s2/s1 of 33 is the same as the lead secondary battery B7.

Lead accumulator Q1-Q7

The specific surface area ratio s2/s1 obtained in accordance with the above procedure was adjusted to the value shown in table 5 by adjusting the specific surface area of each carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery C7, and lead storage batteries Q1 to Q7 were assembled in the same manner as in lead storage battery a1, except that the obtained negative electrode plates were used. The lead secondary battery Q3 having a specific surface area ratio s2/s1 of 33 was the same as the lead secondary battery C7.

Lead storage battery S1-S7

The specific surface area ratio s2/s1 obtained in accordance with the above procedure was adjusted to the value shown in table 5 by adjusting the specific surface area of each carbon material used. Except for this, a negative electrode plate was produced in the same manner as in the lead storage battery D7, and a lead storage battery was assembled in the same manner as in the lead storage battery a1 except that the obtained negative electrode plate was used. The lead secondary battery S3 having a specific surface area ratio S2/S1 of 33 was the same as that of the lead secondary battery D7.

Lead accumulator T1-T7

The specific surface area ratio s2/s1 obtained in accordance with the above procedure was adjusted to the value shown in table 5 by adjusting the specific surface area of each carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery B1, and lead storage batteries T1 to T7 were assembled in the same manner as in lead storage battery a1 except that the obtained negative electrode plates were used. Lead acid battery T3 having a specific surface area ratio s2/s1 of 28 was the same as lead acid battery B1.

Similar to lead storage battery a1, evaluation 1 to evaluation 3 were performed for lead storage batteries O1 to O7, P1 to P7, Q1 to Q7, S1 to S7, and T1 to T7. The evaluation results are shown in table 5.

[ Table 5]

As shown in table 5, when the specific surface area ratio S2/S1 is 20 or more, high PSOC lifetime performance can be maintained, low-temperature high-rate performance after high-temperature cycle is further improved, and high regeneration acceptability can be ensured to some extent (O2 to O7, P2 to P7, Q2 to Q7, S2 to S7, and T2 to T7). It is considered that the reason why high low-temperature high-rate performance is obtained is that the adsorption of the organic shrinkproof agent can be suppressed because the specific surface area of each carbon material is in an appropriate range. When the specific surface area ratio s2/s1 is 20 or more, the PSOC life performance is greatly improved as compared with the case where the specific surface area ratio s2/s1 is less than 20. This is considered to be because when the specific surface area ratio s2/s1 is 20 or more, the reduction reaction of lead sulfate is easily performed. When the specific surface area ratio S2/S1 is 240 or less, the increase in the amount of liquid reduction after the circulation can be suppressed (O1 to O6, P1 to P6, Q1 to Q6, S1 to S6, T1 to T6), but the detailed mechanism thereof is not yet determined.

Lead accumulator U1-U8

The average aspect ratio obtained in the above procedure was adjusted to the value shown in table 6 by adjusting the average aspect ratio of the carbon material used. Except for this, negative electrode plates were produced in the same manner as in the lead storage battery a7, and the lead storage batteries U1 to U8 were assembled in the same manner as in the lead storage battery a1, except that the obtained negative electrode plates were used.

Lead accumulator V1-V8

The average aspect ratio obtained in the above procedure was adjusted to the value shown in table 6 by adjusting the average aspect ratio of the carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery B7, and lead storage batteries V1 to V8 were assembled in the same manner as in lead storage battery a1, except that the obtained negative electrode plates were used.

Lead accumulator W1-W8

The average aspect ratio obtained in accordance with the procedure described above was adjusted to the value shown in table 6 by adjusting the average aspect ratio of the carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery C7, and lead storage batteries W1 to W8 were assembled in the same manner as in lead storage battery a1 except that the obtained negative electrode plates were used.

Lead accumulator X1-X8

The average aspect ratio obtained in accordance with the procedure described above was adjusted to the value shown in table 6 by adjusting the average aspect ratio of the carbon material used. Except for this, a negative electrode plate was produced in the same manner as in the lead storage battery D7, and the lead storage batteries X1 to X8 were assembled in the same manner as in the lead storage battery a1 except that the obtained negative electrode plate was used.

Lead accumulator Y1-Y8

The average aspect ratio obtained in the above procedure was adjusted to the value shown in table 6 by adjusting the average aspect ratio of the carbon material used. Except for this, negative electrode plates were produced in the same manner as in lead storage battery B2, and lead storage batteries Y1 to Y8 were assembled in the same manner as in lead storage battery a1, except that the obtained negative electrode plates were used.

Similar to lead storage battery a1, lead storage batteries U1 to U8, V1 to V8, W1 to W8, X1 to X8, and Y1 to Y8 were evaluated for PSOC life performance in evaluation 1 and evaluation 2. The evaluation results are shown in table 6. When the average aspect ratio of the 1 st carbon material was adjusted, the powder resistance ratio R2/R1 and the specific surface area ratio s2/s1 were also changed. These values are also shown in table 6.

[ Table 6]

As shown in Table 6, when the average aspect ratio of the first carbon material 1 is 1.5 or more, the PSOC life performance is further improved (U2-U8, V2-V8, W2-W8, X2-X8, Y2-Y8). This is considered to be because when the average aspect ratio is 1.5 or more, a conductive network is easily formed in the negative electrode material, and the formed conductive network is easily maintained by suppressing the outflow of the organic shrink-proofing agent during high-temperature cycling. On the other hand, it was observed that if the average aspect ratio of the 1 st carbon material becomes large, there is a tendency that the PSOC lifetime performance and the low-temperature high-rate performance are decreased (U8, V8, W8, X8, Y8). This is considered to be because cracks are likely to be generated on the surface of the negative electrode plate when the negative electrode plate is produced, and thus a conductive network is not likely to be formed. Therefore, from the viewpoint of further increasing the effect of improving PSOC lifetime performance and low-temperature high-rate performance after high-temperature cycles, the average aspect ratio of the 1 st carbon material is preferably 1.5 to 35(U2 to U7, V2 to V7, W2 to W7, X2 to X7, and Y2 to Y7).

Industrial applicability

The lead acid battery according to one aspect of the present invention is applicable to valve-regulated and liquid-regulated lead acid batteries, and can be suitably used as a power source for starting an automobile, a bicycle, or the like, a power source for storing natural energy, an industrial power storage device for an electric vehicle (a forklift, or the like), or the like.

Description of the symbols

1 lead accumulator

2 negative plate

2a negative electrode plate ear

3 Positive plate

4 spacer

5 positive electrode shed part

6 negative electrode shed part

7 positive pole

8-pass-through connector

9 negative pole column

11 polar plate group

12 Battery jar

13 bulkhead

14 cell compartment

15 cover

16 negative terminal

17 positive terminal

18 liquid port plug

Claims (22)

1. A lead-acid battery is provided,

the lead storage battery comprises a negative electrode plate, a positive electrode plate and an electrolyte,

the negative electrode plate contains a negative electrode material containing a carbon material and an organic shrinkproof agent,

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,

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

the organic shrink-proofing agent comprises a1 st organic shrink-proofing agent having an aromatic ring and a2 nd organic shrink-proofing agent having an aromatic ring,

the content of sulfur element in the No. 1 organic shrink-proof agent is more than 4000 mu mol/g,

the content of sulfur element in the No. 2 organic shrink-proof agent is less than 2000 mu mol/g.

2. The lead-acid battery according to claim 1, wherein the 1 st organic shrinkproof agent is contained in an amount of 0.02 to 0.12 mass% and the 2 nd organic shrinkproof agent is contained in an amount of 0.05 to 0.7 mass% in the negative electrode material.

3. The lead-acid battery according to claim 1 or 2, wherein a ratio s2/s1 of a specific surface area s2 of the 2 nd carbon material to a specific surface area s1 of the 1 st carbon material is 20 to 240.

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 to 35.

5. The lead storage battery according to any one of claims 1 to 4, wherein the content of elemental sulfur in the 1 st organic shrinkproof agent is 9000 μmol/g or less.

6. The lead-acid battery according to any one of claims 1 to 5, wherein the content of the sulfur element in the 1 st organic shrinkproof agent is 6000 μmol/g or more.

7. The lead-acid battery according to any one of claims 1 to 6, wherein the content of sulfur element in the No. 2 organic shrinkproof agent is 1000. mu. mol/g or less.

8. The lead-acid battery according to any one of claims 1 to 7, wherein the content of sulfur element in the No. 2 organic shrinkproof agent is 400. mu. mol/g or more.

9. The lead-acid battery according to any one of claims 1 to 8, wherein the content of the 1 st organic shrinkproof agent in the negative electrode material is 0.05 mass% or more.

10. The lead-acid battery according to any one of claims 1 to 9, wherein the content of the 1 st organic shrinkproof agent in the negative electrode material is 0.10% by mass or less.

11. The lead-acid battery according to any one of claims 1 to 10, wherein the content of the 2 nd organic shrinkproof agent in the negative electrode material is 0.5% by mass or less.

12. The lead-acid battery according to any one of claims 1 to 11, wherein the content of the 1 st carbon material in the negative electrode material is 0.05 mass% or more.

13. The lead-acid battery according to any one of claims 1 to 12, wherein the content of the 1 st carbon material in the negative electrode material is 3.0 mass% or less.

14. The lead-acid battery according to any one of claims 1 to 13, wherein the content of the 2 nd carbon material in the negative electrode material is 0.03 mass% or more.

15. The lead-acid battery according to any one of claims 1 to 14, wherein the content of the 2 nd carbon material in the negative electrode material is 1.0 mass% or less.

16. A lead storage battery according to any one of claims 1 to 15, wherein the ratio R2/R1 is 30 or more.

17. A lead storage battery according to any one of claims 1 to 16, wherein the ratio R2/R1 is 130 or less.

18. A lead storage battery according to any one of claims 1 to 17, wherein the ratio s2/s1 is 30 or more.

19. A lead storage battery according to any one of claims 1 to 18, wherein the ratio s2/s1 is 120 or less.

20. The lead-acid battery according to any one of claims 1 to 19, wherein the 1 st carbon material has an average aspect ratio of 5 or more.

21. The lead-acid battery according to any one of claims 1 to 20, wherein the 1 st carbon material has an average aspect ratio of 30 or less.

22. The lead-acid battery according to any one of claims 1 to 21, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

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