CN110462899B

CN110462899B - Lead-acid battery

Info

Publication number: CN110462899B
Application number: CN201880022389.6A
Authority: CN
Inventors: 小山洁
Original assignee: GS Yuasa International Ltd
Current assignee: GS Yuasa International Ltd
Priority date: 2017-04-28
Filing date: 2018-04-26
Publication date: 2022-06-03
Anticipated expiration: 2038-04-26
Also published as: WO2018199242A1; JPWO2018199242A1; CN110462899A; JP7180591B2

Abstract

A lead-acid battery includes a negative electrode plate and a positive electrode plate. The negative electrode plate contains a negative electrode material containing a carbon material and barium sulfate. The carbon material contains a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m, and the ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material, that is, R2/R1 exceeds 15 and is less than 230. The content of barium sulfate in the negative electrode material is 0.2 to 0.7 mass%. The density of the negative electrode material is 3.8g/cm³The above.

Description

Lead-acid battery

Technical Field

The present invention relates to a lead storage battery.

Background

Lead storage batteries are used for various purposes other than vehicle use and industrial use. The lead storage battery comprises a negative electrode plate, a positive electrode plate and an electrolyte. The negative electrode plate contains a current collector and a negative electrode material. The negative electrode material contains a carbon material, barium sulfate, and the like. Patent document 1 proposes a negative electrode material containing graphite or carbon fiber, carbon black, and barium sulfate and having a density of 3.6 to 4.0g/cm³. Patent document 2 proposes a negative electrode material containing less than 0.6 mass% of barium sulfate and having a density of more than 3.6g/cm³. Patent document 2 describes that the carbon content of the negative electrode material is 0.2 mass% or less, and acetylene black is used as carbon.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2016-152131

Patent document 2: japanese patent laid-open publication No. 2016 & 189260

Disclosure of Invention

Generally, if the density of the negative electrode material is increased, the cycle life is increased. However, when forming a negative electrode plate having a high density of the negative electrode material, if carbon black is added to the negative electrode material, the coating property with respect to the current collector is lowered. Further, depending on the composition of the negative electrode material, it may become difficult to charge after deep discharge, and the cycle life may be reduced.

The invention aims to facilitate the production of a negative electrode plate and improve the cycle life performance of a lead storage battery when deep discharge is performed.

One aspect of the present invention relates to a lead storage battery,

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

the negative electrode plate contains a negative electrode material containing a carbon material and barium sulfate,

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

the ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material, that is, R2/R1 is more than 15 and less than 230,

the content of barium sulfate in the negative electrode material is 0.2 to 0.7 mass%,

the density of the negative electrode material is 3.8g/cm³The above.

According to the above aspect of the present invention, the negative electrode plate can be easily produced, and high cycle life performance of the lead-acid battery can be obtained even when deep discharge is performed.

Drawings

Fig. 1 is a perspective view schematically showing a state where a cover of a lead-acid battery according to an aspect of the present invention is removed.

Fig. 2A is a front view of the lead acid battery of fig. 1.

Fig. 2B is a sectional view of the lead-acid battery shown in fig. 2A, as viewed in the direction of the arrows along line IIB-IIB.

Fig. 3 is a graph showing the relationship between the cycle life performance and the density of the negative electrode material obtained by evaluating lead storage batteries a1 to A8 and B1 to B8.

Fig. 4 is a graph showing the relationship between the cycle life performance obtained by evaluating lead-acid batteries A3, a11 to a16, B3, and B11 to B16 and the content of barium sulfate in the negative electrode material.

Detailed Description

A lead-acid battery according to one aspect of the present invention includes a negative electrode plate and a positive electrode plate. The negative electrode plate contains a negative electrode material containing a carbon material and barium sulfate. The carbon material contains a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m. The ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material, namely R2/R1, is more than 15 and less than 230. The content of barium sulfate in the negative electrode material is 0.2-0.7 mass%, and the density of the negative electrode material is 3.8g/cm³The above.

It is generally known that if the density of a negative electrode material is increased in a negative electrode plate of a lead-acid battery, the conductivity of the negative electrode material is increased, and the distance between negative electrode active materials contained in the negative electrode material is shortened, thereby leading to Pb²⁺The diffusion rate of ions increases, and the charge reaction rate increases. Therefore, when the density of the negative electrode material is high, accumulation of lead sulfate in the negative electrode plate is suppressed, and cycle life performance is considered to be improved.

On the other hand, conventionally, carbon black has been added to the negative electrode material from the viewpoint of improving conductivity. The negative electrode plate can be produced using a paste containing a negative electrode material, but a large amount of the solvent contained in the paste is adsorbed by carbon black. Therefore, in the conventional paste containing carbon black, the fluidity and spreadability of the paste are greatly reduced, and the applicability of the paste to the current collector becomes extremely low. In general, from the viewpoint of uniformly applying the negative electrode material to the current collector, application by a device such as a special purpose filling machine (coater) using the coating paste is employed. However, when the density of the negative electrode material is increased, the solid content of the paste increases, and thus the applicability of the paste in particular decreases. For example, if carbon black is added alone to the negative electrodeWhen the content of carbon black in the negative electrode material is 0.6 mass%, the upper limit of the density at which the coating by machine can be performed is approximately 3.6g/cm³. Therefore, when carbon black is used alone, it is in excess of 3.6g/cm³On the other hand, when the density of the negative electrode material is high, mechanical coating is more difficult than in the conventional case. When machine-based application of paste is difficult, it is difficult to industrially produce a negative electrode plate.

The inventors noticed that the density of the electrode material at the negative electrode was 3.6g/cm³In the following cases, the cycle life performance was almost unchanged regardless of whether the 1 st carbon material or the 2 nd carbon material was used alone or in combination. In general, the higher the density of the negative electrode material, the higher the cycle life performance and the charge acceptance performance, and the capacity reduction can be suppressed even in the charge-discharge cycle including deep discharge. However, in the results of the studies by the present inventors, it was found that: in the case of using the 1 st carbon material alone, even if the density of the anode electrode material is increased, an additional effect of improving the cycle life is hardly seen.

It is generally known that carbon materials have various powder resistances. It is known that the powder resistance of a powder material varies depending on the shape, particle size, internal structure of the particles, crystallinity of the particles, and the like. According to conventional technical common knowledge, the powder resistance of the carbon material and the resistance of the negative electrode plate of the lead-acid battery do not have a direct relationship, and is not considered to have an influence on cycle life performance.

In addition, for the purpose of suppressing a penetration short circuit or suppressing aggregation of lead sulfate accumulated in a negative electrode plate, it has been conventionally studied to add barium sulfate to a negative electrode material of a lead storage battery. However, since barium sulfate is a nonconductor, depending on the composition of the negative electrode material, even if the density of the negative electrode material is increased, charging may not be performed during a charge-discharge cycle including deep discharge. In this case, the cycle life performance is also reduced.

According to the above aspect of the invention, the density of the electrode material at the negative electrode is up to 3.8g/cm³In the above case, the 1 st carbon material having a powder resistance ratio R2/R1 of more than 15 and less than 230 is different in particle sizeThe feedstock and the 2 nd carbon material are combined. This increases the spreadability of the paste containing the negative electrode material (hereinafter also referred to as negative electrode paste), and improves the coatability, so that the negative electrode paste can be mechanically coated even when the negative electrode paste is prepared, despite the high density of the negative electrode material, and the negative electrode plate can be easily produced. As described above, according to the above aspect of the present invention, the negative electrode plate can be easily produced even when the density of the negative electrode material is high. It is considered that the reason why the coating property of the negative electrode paste is improved when the powder resistance ratio R2/R1 is in the above range is that when the powder resistance ratio R2/R1 is in the above range, the surface state of each carbon material is optimized and the adsorption of the solvent can be appropriately suppressed.

In the present specification, the excellent applicability of the negative electrode paste means that the negative electrode paste can be applied to the negative electrode current collector by a machine (specifically, a Paster).

In addition, according to the above aspect of the present invention, by combining the 1 st carbon material and the 2 nd carbon material, the 1 st carbon material and the 2 nd carbon material can be more uniformly filled into the layer of the negative electrode material having a high density. Therefore, many conductive networks are easily formed in the anode electrode material. Increasing the density of the negative electrode material results in the formation of a dense conductive network and a charging reaction field containing metallic lead particles, and the rate of the charging reaction in the negative electrode material increases, leading to improved cycle life performance.

Further, by setting the content of barium sulfate in the negative electrode material to 0.2 to 0.7 mass%, charge and discharge can be repeated even when a charge and discharge cycle involving deep discharge is performed. Therefore, even in the case of deep discharge, the cycle life performance of the lead-acid battery can be suppressed from being degraded. From the viewpoint of further improving the effect of improving the cycle life performance, the content of barium sulfate in the negative electrode material is preferably 0.2 to 0.6 mass%.

The density of the negative electrode material is preferably 4.1g/cm³The above. Even when the density of the negative electrode material is high, the coating property of the negative electrode plate is high, and therefore, a uniform layer of the negative electrode material is easily formed. In addition, since many leads are formedElectrical networks, and therefore cycle life performance can be further improved.

In general, when the density of the negative electrode material is increased, the amount of dilute sulfuric acid used in preparing the paste is decreased and/or the concentration of sulfuric acid in the dilute sulfuric acid is decreased in order to maintain the coating property of the paste. As a result, the amount of sulfate in the negative electrode material decreases. If the amount of sulfate is reduced, the spreadability of the paste is generally enhanced, while the amount of lead sulfate in the negative electrode material in the obtained negative electrode plate is reduced. It is known that when such a negative electrode plate (non-chemically converted negative electrode plate) is stored in the atmosphere, the content of lead carbonate in the negative electrode material increases. It is found that if the content of lead carbonate in the negative electrode material is increased, the negative electrode material may fall off and the initial capacity of the negative electrode plate may be reduced. For example, if a non-chemically converted negative electrode plate containing lead carbonate in an amount of approximately 20 mass% or more in the negative electrode material is chemically converted, the negative electrode material may fall off and the initial capacity of the negative electrode plate may be reduced. That is, the storage performance of the negative electrode plate that has not been chemically converted is lowered. From the viewpoint of suppressing the deterioration of the preservation performance of the negative electrode plate that has not been chemically converted, a conventionally employed method includes, for example, a method in which the negative electrode plate after coating with a paste is brought into contact with dilute sulfuric acid to cause sulfate to penetrate into the surface of the negative electrode plate. However, even by such a method, it is not possible to supply sulfate radicals that sufficiently maintain storage properties.

In the above aspect of the present invention, if the density of the negative electrode material is too high, it may be difficult to obtain high storage performance. Therefore, from the viewpoint of securing high storage stability of the non-chemically-converted negative electrode plate, it is preferable to make the density of the negative electrode material less than 4.7g/cm³。

In the preparation of the anode paste, it is preferable to add a carbon material which does not lower the spreadability and storage property of the anode paste so as not to decrease the sulfate radical amount. As such a carbon material, it is preferable to use a1 st carbon material and a1 st carbon material having a specific surface area S1 ratio of S2 of the 2 nd carbon material to S1 of the 1 st carbon material, that is, S2/S1 of 350 or less2 carbon material. The 1 st carbon material and the 2 nd carbon material showing such S2/S1 ratio are effective particularly in the case where the density of the negative electrode material is less than 4.7g/cm³Is apparent. When the specific surface area ratio S2/S1 is 350 or less, the applicability of the anode paste is improved.

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

(negative plate)

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

A member such as a spacer or coated paper may be attached to the negative electrode plate. When the negative electrode plate includes such a member (attached member), the negative electrode material is obtained by removing the negative electrode current collector and the attached member. However, the thickness of the electrode plate is the thickness including the gasket. In the case where the spacer is attached to the spacer, the thickness of the spacer is also included in the thickness of the spacer.

The negative electrode material contains a negative electrode active material (lead or lead sulfate) that develops capacity by an oxidation-reduction reaction. The negative electrode active material in a charged state is spongy metallic lead, but a negative electrode plate that has not been chemically converted can be generally produced using lead powder. The negative electrode material contains a carbon material and barium sulfate. The negative electrode material may further contain an organic shrinkproof agent or the like, and may contain other additives as necessary.

(carbon Material)

The carbon material contains a1 st carbon material having a particle diameter of 32 [ mu ] m or more and a2 nd carbon material having a particle diameter of less than 32 [ mu ] m. The 1 st carbon material and the 2 nd carbon material are separated 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, furnace black, and lamp black. The graphite may be any carbon material as long as it has a graphite-type crystal structure, and may be either artificial graphite or natural graphite.

The Raman spectrum of the 1 st carbon material was measured at 1300cm^-1～1350cm^-1Peak (D band) and 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.

The kind, specific surface area, aspect ratio, and the like of the carbon materials used for preparing the negative electrode material may be selected or adjusted so that the ratio of the powder resistance R2 of the 2 nd carbon material to the powder resistance R1 of the 1 st carbon material, that is, R2/R1 exceeds 15 and is less than 230. 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 1 st carbon material and the 2 nd carbon material 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. In particular, the 1 st carbon material preferably contains at least graphite. The 2 nd carbon material preferably contains at least carbon black. When these carbon materials are used, the powder resistance ratio R2/R1 can be easily adjusted.

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 more than 15 and less than 230. When the powder resistance ratio is in such a range, the negative electrode paste can have high coatability and can have improved cycle life performance. From the viewpoint of obtaining higher cycle life performance, the powder resistance ratio R2/R1 is preferably 80 or more. From the same viewpoint, the powder resistance ratio R2/R1 is preferably 220 or less. From the viewpoint of ensuring high storage stability of the non-chemically converted negative electrode plate, the powder resistance ratio R2/R1 is preferably less than 160, and more preferably 150 or less. These lower and upper limits may be arbitrarily combined. The powder resistance ratio R2/R1 is, for example, more than 15 and 220 or less (or 160 or 150 or less), 80 or more and less than 230 (or 220 or less, 160 or 150 or less).

Specific surface area S2 phase of No. 2 carbon MaterialThe specific surface area S1 ratio of the No. 1 carbon material, S2/S1, is preferably 350 or less. When the specific surface area ratio S2/S1 is in such a range, the applicability of the anode paste can be further improved even when the density of the anode electrode material is increased. In addition, when the 1 st carbon material and the 2 nd carbon material having an S2/S1 ratio of 350 or less are used, high storage performance of the negative electrode plate that is not chemically converted can be ensured. The effect of storage property based on the S2/S1 ratio is particularly in the case where the density of the negative electrode material is less than 4.7g/cm³(preferably 4.6 g/cm)³Hereinafter, more preferably 4.5g/cm³Below) appears.

The average aspect ratio of the 1 st carbon material may be 1 to 200, 1.5 to 100, or 1.5 to 35.

The total content of the 1 st carbon material and the 2 nd carbon material in the negative electrode material is, for example, 0.1 mass% or more, preferably 0.2 mass% or more, and preferably 0.3 mass% or more from the viewpoint of further improving the effect of improving the cycle life performance. The upper limit of the total content of the 1 st carbon material and the 2 nd carbon material also depends on the density of the negative electrode material, the type of each carbon material, and the like, and may be, for example, 1.5 mass% or less.

Among the above carbon materials, the content of the 1 st carbon material in the negative electrode material is, for example, 0.05% by mass or more, and preferably 0.1% by mass or more or 0.2% by mass or more from the viewpoint of high applicability of the negative electrode paste and high cycle life improvement effect. The upper limit of the content of the 1 st carbon material in the negative electrode material depends on the density of the negative electrode material, the kind of the carbon material, and the like, and is, for example, 1.5 mass% or less, and the total content of the 1 st carbon material and the 2 nd carbon material may be adjusted to the above range.

The content of the 2 nd carbon material in the negative electrode material is, for example, 0.03 mass% or more, and is preferably 0.1 mass% or more, and may be 0.2 mass% or more, from the viewpoint of easily forming a conductive network in the negative electrode material. The upper limit of the content of the 2 nd carbon material in the negative electrode material depends on the density of the negative electrode material, the kind of the carbon material, and the like, and is, for example, 1 mass% or less, preferably 0.6 mass% or less, and more preferably 0.4 mass% or less. The content of the 2 nd carbon material may be adjusted so that the total content of the 1 st carbon material and the 2 nd carbon material is in the above range. The content of the 2 nd carbon material may be, for example, 0.03 to 1 mass% (or 0.6 to 0.4 mass%), 0.1 to 1 mass% (or 0.6 to 0.4 mass%), or 0.2 to 1 mass% (or 0.6 to 0.4 mass%).

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

(A) Analysis of carbon Material

(A-1) separation of carbon Material

The lead storage battery in a fully charged state, which has been chemically converted, 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 soluble components. The sample thus pretreated was collected by filtration. The collected sample was passed through a sieve having a mesh opening 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 was wet-sieved using a sieve having a mesh size of 32 μm, the material that did not pass through the mesh size and remained on the sieve was defined as the 1 st carbon material, and the material that passed through the mesh size was defined as the 2 nd carbon material. That is, the particle size of each carbon material is based on the mesh size of the sieve. Wet sieving can 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 while spraying ion-exchanged water, thereby performing sieving. The 1 st carbon material remaining on the sieve is recovered from the sieve by washing the ion-exchanged water, and is separated from the ion-exchanged water by filtration. The 2 nd carbon material passing through the sieve was recovered by filtration using a membrane filter (mesh size 0.1 μm) made of nitrocellulose. The recovered 1 st carbon material and 2 nd carbon material were dried at a temperature of 110 ℃ for 2 hours, respectively. As a sieve having a mesh size of 32 μm, a sieve having a mesh size of JIS Z8801-1: a sieve with a mesh having a nominal (nominal) mesh size of 32 μm as specified 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 procedure and calculating the ratio (% by mass) of the mass in 5g of the pulverized sample.

In the present specification, in the case of a flooded battery, the fully charged state of the lead acid battery refers to a state in which the lead acid battery is charged in a water tank at 25 ℃ for 2 hours at 0.2CA after being charged at a constant current until reaching 2.5V/cell and then at 0.2CA for 2 hours. In the case of a valve-regulated battery, the fully charged state refers to a state in which constant-current constant-voltage charging of 2.23V/cell is performed at 0.2CA in an air tank at 25 ℃, and charging is terminated when the charging current during constant-voltage charging is 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, as long as the battery has a nominal capacity of 30Ah, 1CA is 30A and 1mCA is 30 mA.

(A-2) powder resistance of carbon Material

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

(A-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 using the BET formula using the 1 st carbon material and the 2 nd carbon material separated in the step (a-1) by a gas adsorption method. Each carbon material was pretreated by heating at a temperature of 150 ℃ for 1 hour in a nitrogen stream. The BET specific surface area of each carbon material was determined using the pretreated carbon material under the following conditions using the following apparatus.

A measuring device: TriStar3000 manufactured by Micromeritics

Adsorbing gas: nitrogen with purity over 99.99 percent

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

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

(A-4) average aspect ratio of the 1 st carbon Material

The 1 st carbon material separated in the above-described step (A-1) was observed with an optical microscope or an electron microscope, and 10 or more arbitrary particles were selected and a magnified photograph thereof was taken. Next, the image of each particle was processed to obtain the maximum diameter d1 of the particle and the maximum diameter d2 in the direction orthogonal to the maximum diameter d1, and the aspect ratio of each particle was obtained by dividing d1 by d 2. The obtained aspect ratios were averaged to calculate an average aspect ratio.

(barium sulfate)

The content of barium sulfate contained in the negative electrode material may be 0.2 to 0.7 mass%. When the content of barium sulfate is within such a range, the electron conductivity between the metallic lead particles is not inhibited, and therefore lead sulfate is easily reduced during charging even when deep discharge is performed. This makes it difficult to suppress charging during a charge-discharge cycle associated with deep discharge. Therefore, even in a charge-discharge cycle involving deep discharge, charge and discharge can be repeated, and the reduction in cycle life performance is suppressed. From the viewpoint of further improving the effect of improving the cycle life performance, it is preferably 0.2 to 0.6 mass%.

A method for determining the content of barium sulfate contained in the negative electrode material will be described below.

(B) Analysis of barium sulfate

(B-1) The ground sample was taken out of the lead-acid battery in the same manner as in (A-1), and about 5g of the sample was taken out of the lead-acid battery, and the mass m1(g) was accurately weighed. The weighed sample was charged into a 10 mass% nitric acid aqueous solution of 30cm³In (5), the solution is dissolved by heating. After the resulting mixture was cooled, deionized water was added until the volume became 100cm³After standing for 30 minutes, the supernatant was collected into another beaker. Adding ammonium acetate 20g and water 30cm into the rest precipitate³And heating for dissolution. The obtained solution was added to the supernatant liquid, boiled, heated for 5 minutes in this state, and then left to stand for 1 hour. The resulting mixture was filtered through a membrane filter of known mass, and the filtrate was recovered. The components remaining on the membrane filter were thoroughly washed with water. The membrane filter used was dried at 110 ℃ for 2 hours, and the mass after drying was measured. The initial mass of the membrane filter was subtracted from the measured value to determine the insoluble residue mass m 2. And (4) putting the dried membrane filter into a porcelain crucible with known quality, and burning and ashing the membrane filter. Next, the crucible was cooled to room temperature in a dryer to measure the mass, and the initial mass of the crucible was subtracted from the mass to obtain the mass m3 of the burned residue.

(B-2) taking the filtrate recovered in (B-1) above into a volumetric flask, adding deionized water until the volume is 250cm³. Using Air-C by atomic absorption₂H₂The flame was measured by selecting a line of 553.6nm as the atomic absorbance of the resulting solution. The atomic absorbance was measured using an atomic absorption spectrophotometer (AA 7000F, manufactured by shimadzu corporation). The concentration of barium element in the solution was determined from the atomic absorbance based on a calibration curve prepared by separately using a standard concentration Ba salt solution, and the mass m4(mg) of barium element contained in the filtrate was determined. Then, the content c1 (mass%) of soluble barium sulfate contained in the negative electrode material was determined by the following formula.

c1＝100×(M1/M2)×(m4/m1)

Here, M1 is barium sulfate (BaSO)₄) M2 is the atomic weight of barium (Ba). A value of M1/M2 ═ 1.699 was used.

(B-3) the content c2 (mass%) of insoluble barium sulfate contained in the negative electrode material was calculated from the mass m3 of the burned residue of (B-1) by the following formula.

c2＝100×m3/m1

Then, the content (mass%) of barium sulfate contained in the chemically converted and fully charged negative electrode material was determined by summing c1 and c 2.

(organic shrinkproof agent)

The organic shrinkproof agent contained in the negative electrode material is an organic polymer containing a sulfur element, and usually contains 1 or more, preferably a plurality of, aromatic rings in the molecule and also contains a sulfur element as a sulfur-containing group. Among the sulfur-containing groups, a sulfonic acid group or a sulfonyl group which is a stable form is preferable. The sulfonic acid group may be present in an acid form or a salt form as in the case of Na salt.

Examples of the organic shrinkproof agent include lignin-based organic shrinkproof agents and synthetic organic shrinkproof agents. As the synthetic organic anti-shrink agent, a condensate of an aromatic compound having a sulfur-containing group and formaldehyde can be used. Examples of the lignin include lignin, lignin sulfonic acid or a lignin derivative such as a salt thereof (e.g., an alkali metal salt such as a sodium salt). The organic shrink-proofing agent can be used singly or in combination of two or more. For example, a lignin-based condensate of an aromatic compound having a sulfur-containing group and formaldehyde may be used in combination. As the aromatic compound, bisphenols, biphenyls, naphthalenes, and the like are preferably used.

The content of the organic shrink preventing agent contained in the negative electrode material is, for example, 0.01 to 1.0 mass%, and preferably 0.02 to 0.8 mass% or less.

Hereinafter, a method for determining the organic shrinkproof agent contained in the negative electrode material is described. Before quantitative analysis, the lead-acid battery after chemical conversion is fully charged and then disassembled to obtain a negative electrode plate as an analysis object. 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.

[ organic shrinkproof agent ]

The organic shrinkproof agent was extracted by pulverizing an initial sample which had not been pulverized, and immersing the pulverized initial sample in a 1mol/L aqueous NaOH solution. Insoluble components were removed by filtration from the aqueous NaOH solution containing the extracted organic shrinkproofing agent. The obtained filtrate (hereinafter, also referred to as an analysis target filtrate) is desalted, concentrated, and dried to obtain powder of the organic anti-shrinking agent (hereinafter, also referred to as an analysis target powder). Desalting can be performed by filling the filtrate in a dialysis tube and immersing the tube in distilled water.

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

The ultraviolet-visible absorption spectrum of the filtrate to be analyzed was measured. The content of the organic shrink-proofing agent in the negative electrode material was quantified using the spectral intensity and a calibration curve prepared in advance. In the case where the structural formula of the organic shrinkproof agent to be analyzed cannot be strictly determined and the calibration curve of the same organic shrinkproof agent cannot be used, the calibration curve is prepared using an available organic shrinkproof agent showing an ultraviolet-visible absorption spectrum, an infrared spectroscopic spectrum, an NMR spectrum, or the like similar to the organic shrinkproof agent to be analyzed.

(Density of negative electrode Material)

The density of the negative electrode material is only 3.8g/cm³The concentration of the above-mentioned solvent is preferably 4.1g/cm³The above. Even in the case of such a large density, high coatability and excellent cycle life performance can be obtained in the present invention. In addition, the storage performance of the non-chemically-converted negative electrode plate can be improved. The density of the negative electrode material is, for example, 4.7g/cm³The following. From the viewpoint of easily ensuring high storage stability of the non-chemically converted negative electrode plate, it is preferably less than 4.7g/cm³More preferably 4.6g/cm³Below or 4.5g/cm³The following. These lower and upper limits may be arbitrarily combined. Negative electrodeThe density of the electrode material is, for example, 3.8g/cm³～4.7g/cm³(alternatively less than 4.7 g/cm)³、4.6g/cm³Below or 4.5g/cm³Below), 4.1g/cm³～4.7g/cm³(alternatively less than 4.7 g/cm)³、4.6g/cm³Below or 4.5g/cm³Below).

The density of the negative electrode material is a value of the bulk density of the negative electrode material in a fully charged state after chemical conversion, and is measured as follows. The battery after chemical conversion is fully charged and then disassembled, and the obtained negative electrode plate is washed with water and dried, thereby removing the electrolyte in the negative electrode plate. Next, the negative electrode material was separated from the negative electrode plate to obtain an unpulverized measurement sample. The bulk density of the negative electrode material is determined by charging a sample into a measuring vessel, evacuating the vessel, filling the vessel with mercury at a pressure of 0.5 to 0.55psia (. apprxeq.3.45 to 3.79kPa), measuring the bulk volume of the negative electrode material, and dividing the mass of the measured sample by the bulk volume. Note that the volume obtained by subtracting the injection volume of mercury from the volume of the measurement container is defined as the deposition volume. The density of the negative electrode material was measured by using an automatic mercury porosimeter (AutoPore IV9505) manufactured by shimadzu corporation.

(others)

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

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 alloys may further contain at least 1 kind selected from Ba, Ag, Al, Bi, As, Se, Cu, and the like As an additive element. Among them, a Pb-Sb alloy is preferable, and the alloy may further contain at least 1 kind selected from Ag, Al, As, Se, and the like As an additive element.

The negative electrode plate can be formed by filling a negative electrode paste in a negative electrode current collector, aging and drying the negative electrode paste to produce a non-chemically-converted negative electrode plate, and then chemically converting the non-chemically-converted negative electrode plate. The negative electrode paste is prepared by adding water and dilute sulfuric acid to lead powder, a carbon material, and, if necessary, an organic shrinkage inhibitor and/or various additives, and kneading them. At the time of aging, the negative electrode plate that has not been chemically converted is preferably aged at a temperature higher than room temperature and at a high humidity.

The chemical conversion of the negative electrode plate can be performed by charging the electrode plate group including the non-chemically converted negative electrode plate in a state in which the electrode plate group is immersed in an electrolytic solution containing sulfuric acid in a cell of the lead-acid battery. Alternatively, the chemical conversion may be performed prior to assembly of the lead-acid battery or the plate package. The sponge-like metallic lead is produced by chemical conversion.

(Positive plate)

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

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

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

Examples of the lead alloy used for the positive electrode current collector include a Pb — Ca alloy, a Pb — Sb alloy, and a Pb — Ca — Sn alloy. Among them, Pb-Sb alloys are preferably used.

The positive electrode material contains a positive electrode active material (lead dioxide or lead sulfate) having a capacity due to an oxidation-reduction reaction. The positive electrode material may contain other additives as needed.

The paste-type positive electrode plate that is not chemically converted is obtained by filling a positive electrode collector with a positive electrode paste, curing the paste, and drying the paste, depending on the case of the negative electrode plate. 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 is inserted with lead powder or slurry-like lead powder, and connecting the tubes with a connecting seat.

The formed non-chemically transformed positive plate is further chemically transformed. Lead dioxide is generated by chemical conversion. The chemical conversion of the positive plates can be carried out before the assembly of the lead accumulator or of the plate group.

(spacer)

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

The non-woven fabric is a mat made of non-woven fibers by complexing, and the non-woven fabric takes the fibers as a main body. 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, for example, 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 is obtained by, for example, 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, or the like.

(electrolyte)

The electrolyte is an aqueous solution containing sulfuric acid, and is used in chemical conversionThe specific gravity of the electrolyte in the lead-acid battery in a fully charged state after conversion at 20 ℃ is, for example, 1.10g/cm³～1.35g/cm³Preferably 1.10g/cm³～1.30g/cm³Or 1.20g/cm³～1.30g/cm³。

Fig. 1 is a perspective view schematically showing an example in which a cover of a lead-acid battery according to an embodiment of the present invention is removed. Fig. 2A is a front view of the lead-acid battery of fig. 1, and fig. 2B is a sectional view of the lead-acid battery shown by an arrow on line IIB-IIB of fig. 2A.

The lead storage battery 1 includes a cell 10 that houses an electrode group 11 and an electrolyte 12. 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 negative electrode plate 2 is covered with the bag-shaped separator 4, but the form of the separator is not particularly limited.

A current collecting lug (not shown) projecting upward is provided on each of the plurality of negative electrode plates 2. A current collecting lug (not shown) projecting upward is also provided at the upper portion of each of the plurality of positive electrode plates 3. The lug portions of the negative electrode plate 2 are connected and integrated by a negative electrode bus bar 5 a. Similarly, the lug portions of the positive electrode plate 3 are also connected and integrated by the positive electrode bus bar 5 b. The lower end of the negative post 6a is fixed to the upper portion of the negative bus bar 5a, and the lower end of the positive post 6b is fixed to the upper portion of the positive bus bar 5 b.

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 storage battery,

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

the density of the negative electrode material is 3.8g/cm³The above.

(2) In the above (1), the above ratio, R2/R1, is preferably 80 or more and less than 230.

(3) In the above (1) or (2), the ratio R2/R1 is preferably 80 to 220.

(4) In any one of the above (1) to (3), the negative electrode material preferably has a density of 4.1g/cm³The above.

(5) In any one of the above (1) to (4), the negative electrode material preferably has a density of less than 4.7g/cm³。

(6) In the above (5), the 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, i.e., S2/S1, is preferably 350 or less.

(7) In any one of the above (1) to (6), the content of barium sulfate in the negative electrode material is preferably 0.2 to 0.6% by mass.

(8) In any of the above (1) to (7), the above ratio, i.e., R2/R1, is preferably 80 or more and less than 160.

(9) In any one of the above (1) to (8), the ratio R2/R1 is preferably 80 to 150.

(10) In the above item (6), the negative electrode material preferably has a density of 4.6g/cm³Below or 4.5g/cm³The following.

(11) In any one of the above (1) to (10), the content of the 1 st carbon material in the negative electrode material is preferably 0.05% by mass or more.

(12) In any one of the above (1) to (11), the content of the 1 st carbon material in the negative electrode material is, for example, 1.5% by mass or less.

(13) In any one of the above (1) to (12), the content of the 2 nd carbon material in the negative electrode material is preferably 0.1 mass% or more.

(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 0.6% by mass or less.

(15) In any one of the above items (1) to (14), it is preferable that the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

[ examples ]

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

Lead accumulator A1

A lead-acid battery a1 for forklift (forklifts) having a nominal capacity of 200Ah, in which the positive electrode plates were provided with 3 sheets of clad-type electrode plates and the negative electrode plates were provided with 4 sheets of paste-type electrode plates, was prepared in the following manner.

(1) Production of negative electrode plate

The negative electrode plate was produced by applying a negative electrode paste to a plate-like and grid-like negative electrode collector (length of long side 271mm, length of short side 142mm, thickness 2.8mm to 3.7 mm). At this time, the thicknesses of the negative electrode current collector and the paste coating layer were adjusted so that the mass of the negative electrode material after chemical conversion was 465 ± 6g per 1 negative electrode plate and the density of the negative electrode material was the design value in table 1. The negative electrode paste was applied using a Paster (manufactured by Winkel) so that the grid holes of the current collector were not removed. However, when the negative electrode paste cannot be applied by the Paster, the application is performed manually by using a trowel.

The negative electrode paste was prepared by mixing lead powder, water, dilute sulfuric acid, barium sulfate, a carbon material, and an organic shrinkproof agent with a mixer (manufactured by DALTON).

Carbon black (ketjen black (registered trademark)) and graphite (flaky graphite, average particle diameter D) were used as carbon materials₅₀: 110 μm). Sodium lignosulfonate was used as the organic shrink preventing agent, and the amount of the sodium lignosulfonate was adjusted so that the content of 100 mass% of the negative electrode material became 0.1 mass%, and the sodium lignosulfonate was mixed in the negative electrode paste. The content (design value) of barium sulfate contained in 100 mass% of the negative electrode material was 0.6 mass%. When the anode paste was prepared, the amounts of water and dilute sulfuric acid added to the anode paste were adjusted so that the density of the anode electrode material after having been chemically converted and fully charged became the design values shown in table 1. As already stated, the same shall applyThe described procedure is to disassemble the battery in a fully charged state after chemical conversion, and the density (measured value) of the negative electrode material obtained from the collected measurement sample is almost not different from the designed value.

(2) Production of Positive plate

As the positive electrode plate, a clad plate obtained by filling 14 tubes having an outer diameter of 10mm with a positive electrode material was used. The amount of the positive electrode material applied was adjusted so that the mass of the positive electrode material after chemical conversion was 792 ± 8g per 1 positive electrode plate.

(3) Lead storage battery assembly

The obtained negative and positive electrode plates were immersed in dilute sulfuric acid having a concentration of 7 mass%, and in this state, tank chemical conversion (タンク formation) was performed. The negative electrode plate and the positive electrode plate after the chemical conversion are laminated with a separator interposed therebetween, thereby producing an electrode plate group. Placing the obtained electrode plate group in an electric tank, and injecting into 2000cm³And (3) dilute sulfuric acid having a specific gravity of 1.28 at 20 ℃ to prepare a lead storage battery A1. Similarly, a total of 4 lead-acid batteries a1 were produced.

In the lead-acid battery, the content of the 1 st carbon material contained in the negative electrode material was 0.4 mass%, and the content of the 2 nd carbon material was 0.2 mass%. The powder resistance ratio R2/R1 was 100. The 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) was 350. However, these values are obtained as the contents of the respective carbon materials contained in the negative electrode material (100 mass%) when the negative electrode plate of the manufactured lead-acid storage battery is taken out and the carbon materials contained in the negative electrode material are separated into the 1 st carbon material and the 2 nd carbon material according to the above procedure. The powder resistances R1 and R2, the powder resistance ratio R2/R1, and the specific surface area ratio S2/S1 of the respective carbon materials were also determined from the lead-acid battery produced in accordance with the above procedure.

Lead accumulator A2-A8

The amounts of water and dilute sulfuric acid added to the anode paste were adjusted in such a manner that the design value of the density of the anode electrode material that had been chemically converted became the value shown in table 1. Except for this, a negative electrode plate was produced and the obtained negative electrode plate was used in the same manner as in the case of the lead storage battery a1, and the lead storage batteries a2 to A8 were assembled in the same manner as in the lead storage battery a 1.

Lead accumulator B1-B8

As the carbon material, only carbon black (ketjen black (registered trademark)) was used. In the lead-acid battery, the content of the 2 nd carbon material was 0.6 mass%. Except for this, a negative electrode plate was formed in the same manner as in lead storage battery a 1. A lead storage battery B1 was assembled in the same manner as the lead storage battery a1 except that the obtained negative electrode plate was used.

The amounts of water and dilute sulfuric acid added to the anode paste were adjusted in such a manner that the design value of the density of the anode electrode material that had been chemically converted became the value shown in table 1. Except for this, lead storage batteries B2 to B8 were assembled in the same manner as in the lead storage battery B1, except that a negative electrode plate was produced and the obtained negative electrode plate was used in the same manner as in the case of the lead storage battery B1.

Lead storage batteries D1 and D2

The negative electrode plate was produced without using a carbon material, and the amounts of water and dilute sulfuric acid added to the negative electrode paste were adjusted so that the design value of the density of the chemically converted negative electrode material became the value shown in table 1. Except for this, a negative electrode plate was formed in the same manner as in lead storage battery a 1. Except for using the obtained negative electrode plates, lead storage batteries D1 and D2 were assembled in the same manner as the lead storage battery a 1.

Lead storage batteries E1 and E2

As the carbon material, only carbon black (ketjen black (registered trademark)) was used. In the lead-acid battery, the content of the 2 nd carbon material was 0.2 mass%. Except for this, a negative electrode plate was formed in the same manner as in lead storage battery D1. A lead storage battery E1 was assembled in the same manner as the lead storage battery a1 except that the obtained negative electrode plate was used.

A negative electrode plate was formed in the same manner as in lead storage battery E1, except that the content of the 2 nd carbon material was changed to 0.4 mass%. A lead storage battery E2 was assembled in the same manner as the lead storage battery a1 except that the obtained negative electrode plate was used.

Lead accumulator E3

As the carbon material, only carbon black (ketjen black (registered trademark)) is used. In the lead-acid battery, the content of the 2 nd carbon material was 0.4 mass%. Except for this, a negative electrode plate was formed in the same manner as in lead storage battery D2. A lead storage battery E3 was assembled in the same manner as the lead storage battery a1 except that the obtained negative electrode plate was used.

[ evaluation 1: coating Property)

The components of the negative electrode material were mixed by a mixer (manufactured by DALTON corporation) to prepare a negative electrode paste. Then, the negative electrode paste was applied to a current collector using a Paster (manufactured by Winkel). The state of the coating was evaluated according to the following criteria.

A: the current collector obtained by applying the negative electrode paste in a state where the paste does not fall off from the grid holes of the current collector was obtained at a production rate of 15 sheets/min or more.

B: it is impossible to obtain a current collector obtained by applying the negative electrode paste in a state where the paste is not dropped from the grid holes of the current collector at a production rate of 15 sheets per minute or more.

[ evaluation 2: storage Property of negative plate not chemically converted ]

The content of lead carbonate contained in the negative electrode material when the non-chemically-converted negative electrode plate was stored was determined in accordance with the following procedure.

First, the non-chemically transformed negative electrode plate was aged at 35 ℃ and 90% relative humidity for 2 days, dried at 60 ℃ for 6 hours, and then stored in the atmosphere for 3 weeks. About 5g of the negative electrode material was collected from the negative electrode plate after storage, and the mass W was measured and pulverized. The pulverized sample was immediately put into 50mL of a 20 mass% aqueous perchloric acid solution at room temperature (25 ℃ C.) and left to stand for 10 minutes. The total mass m5 of the sample and the aqueous perchloric acid solution to be put in and the total mass m6 of the sample and the aqueous perchloric acid solution after leaving for 10 minutes were measured. The amount of mass decrease Δ W at this time was determined to be m6-m5, and the content of lead carbonate in the negative electrode material c3 (mass%) was calculated by the following formula.

c3＝ΔW×((M3/M4)/W)×100

Here, M3 is lead carbonate (PbCO)₃) M4 is carbon dioxide(CO₂) Molecular weight of (2). A value of M3/M4 ═ 6.07 was used.

Then, the storage performance of the non-chemically-converted negative electrode plate was evaluated based on the value of the carbonate content c3 in accordance with the following criteria. Note that a small carbonate content M means excellent storage performance.

A: the carbonate content c3 is less than 20 mass%.

B: the carbonate content c3 is 20 mass% or more.

[ evaluation 3: cycle life Property

Cycle life tests were performed on 3 of the 4 fabricated lead-acid batteries. Cycle life test the following cycles of discharging and charging were repeated in a water tank at 35 ℃. At this time, the discharge capacity was determined by discharging the discharge mixture at 30 ℃ to a final voltage of 1.70V at a current of 40A for 100 cycles.

Discharging: discharge at a current of 50A for 3 hours.

Charging: the charge was carried out for 5 hours at a current of 37.5A.

The average discharge capacity was determined from the discharge capacities of 3 lead-acid batteries measured per 100 cycles. The cycle life performance was evaluated by the number of cycles T determined in the following manner at the time T when the average discharge capacity was less than 75% of the nominal capacity 200Ah (i.e., 150 Ah). The case where the number of cycles T is 1450 or more was judged to obtain high cycle life performance.

The number of cycles T was determined from the average discharge capacity Q1 at the time T when the average discharge capacity was first less than 150Ah and the average discharge capacity Q2 at the time of a discharge test before 100 cycles thereof, by the following formula.

T＝t-(150-Q1)/(Q2-Q1)×100

The results of the lead-acid batteries a1 to A8, B1 to B8, D1 to D2, and E1 to E3 are shown in table 1. The results of the cycle life performance among the results of A1 to A8 and B1 to B8 in Table 1 are shown in FIG. 3.

[ Table 1]

As shown in Table 1 and FIG. 3, the density of the negative electrode material was less than 3.8g/cm³In the case of using the 2 nd carbon material alone and the two carbon materials having a powder resistance ratio in a specific range in combination, the cycle life was not substantially changed but was less than 1450 cycles, which was not sufficient (a1, a7, A8, B1, B7, and B8). In contrast, the density of the negative electrode material was 3.8g/cm³In the case of the combination of the 1 st carbon material and the 2 nd carbon material having a powder resistance ratio within the specific range, cycle life performance (a2 to a6) comparable to the case of using the 2 nd carbon material alone (B2 to B6) can be obtained although the content of the 2 nd carbon material is small. It is considered that this is because many conductive networks are easily formed in the anode electrode material by combining the 1 st carbon material and the 2 nd carbon material.

In addition, as shown in Table 1, in the case of using the 2 nd carbon material alone, if the density of the negative electrode material becomes high (specifically, 3.7 g/cm)³Above, 3.8g/cm³In the above case), the negative electrode paste cannot be applied by machine (B1 to B6). In batteries B1 to B6, the storage performance of the negative electrode plate that has not been chemically converted is low. On the other hand, by using the 1 st carbon material and the 2 nd carbon material having a powder resistance ratio in a specific range in combination, the density of the negative electrode material was 3.7g/cm³Above, 3.8g/cm³In the above case, the coating can be performed by a machine (a1 to a 6). This is considered to be because the surface state of each carbon material was optimized by satisfying the specific powder resistance ratio R2/R1 in the batteries a1 to a5, and the adsorption of the solvent was appropriately suppressed. In battery a6, the storage performance of the negative electrode plate that had not been chemically converted was reduced. The density of the negative electrode material is preferably less than 4.7g/cm from the viewpoint of suppressing the deterioration of the storage property³。

Lead accumulator A11-A16

The amount of barium sulfate added was adjusted so that the content of barium sulfate in the anode electrode material that had been chemically converted became the design value shown in table 2. Otherwise, a negative electrode plate was produced and the obtained negative electrode plate was used in the same manner as in the case of the lead storage battery A3, and assembly was performed in the same manner as in the case of the lead storage battery a1Lead storage batteries A11-A16. The density of the negative electrode material in these lead-acid batteries and lead-acid battery A3 was designed to be 4.1g/cm³。

Lead accumulator B11-B16

The amount of addition of barium sulfate was adjusted so that the content of barium sulfate in the anode electrode material that had been chemically converted became the design value shown in table 2. Except for this, lead-acid batteries B11 to B16 were assembled in the same manner as in lead-acid battery a1, except that a negative electrode plate was produced and the obtained negative electrode plate was used in the same manner as in the case of lead-acid battery B3. The designed value of the density of the negative electrode material in these lead-acid batteries and lead-acid battery B3 was 4.1g/cm³。

The lead storage batteries a11 to a16 and B11 to B16 were evaluated in the same manner as the lead storage battery a 1. In addition, the content of barium sulfate in the negative electrode material was measured according to the above procedure. The evaluation results are shown in table 2. The results of the lead acid batteries a3 and B3 are also shown in table 2. The results of the cycle life performance of table 2 are shown in fig. 4.

[ Table 2]

As shown in table 2 and fig. 4, when the content of barium sulfate in the negative electrode material was 0.2 mass% to 0.7 mass% and the 1 st carbon material and the 2 nd carbon material were combined in a specific range of powder resistance ratio, high cycle life performance (a12 to a15, A3) equivalent to that of the 2 nd carbon material alone (B12 to B15, B3) and equal to or higher than 1450 cycles could be obtained, although the content of the 2 nd carbon material was small. The reason why high cycle life performance can be obtained in these batteries is considered to be: by combining the 1 st carbon material and the 2 nd carbon material and setting the barium sulfate content of the negative electrode material to an appropriate range, the electron conductivity between the metallic lead particles of the negative electrode plate is not hindered, and even when deep discharge is performed, lead sulfate is easily reduced during charging, and charging is not hindered. The content of barium sulfate is preferably 0.2 to 0.6% by mass from the viewpoint of obtaining higher cycle life performance.

In lead-acid batteries B11 to B16 and B3, the coating property was evaluated as B, and when the constituent components of the negative electrode material were mixed, the coating could not be performed by machine. The coating properties were markedly improved in the lead secondary batteries a11 to a16 and A3 as compared with these batteries.

Lead accumulator A21-A34

Adjusting the amount, specific surface area and/or average aspect ratio of each carbon material used, and further adjusting the average particle diameter D of each carbon material as necessary₅₀. Acetylene black was used in lead acid battery a27 instead of ketjen black, and activated carbon was used in lead acid batteries a33 and a 34. The powder resistance ratio R2/R1 was changed as shown in Table 3. Except for this, a negative electrode plate was produced in the same manner as in lead storage battery a 3. The lead storage batteries a21 to a34 were assembled in the same manner as the lead storage battery a1 except that the obtained negative electrode plate was used. The design value of the density of the negative electrode material in these lead-acid batteries was 4.1g/cm in the same manner as in lead-acid battery A3³。

Lead accumulator A41-A43

Adjusting the amount, specific surface area and/or average aspect ratio of each carbon material used, and further adjusting the average particle diameter D of each carbon material as necessary₅₀. In the lead secondary battery a43, acetylene black was used instead of ketjen black. The powder resistance ratio R2/R1 was changed as shown in Table 3. Except for this, a negative electrode plate was produced in the same manner as in the lead storage battery a1, and lead storage batteries a41 to a43 were assembled in the same manner as in the lead storage battery a 1. However, the design value of the density of the negative electrode material in these lead-acid batteries was 4.7g/cm in the same manner as in lead-acid battery A6³。

The lead storage batteries a21 to a34 and a41 to a43 were evaluated in the same manner as the lead storage battery a1 for evaluation 1 and evaluation 2. The evaluation results are shown in table 3. The results of the lead acid batteries A3 and a6 are shown together in table 3.

[ Table 3]

As shown in table 3, when the powder resistance ratio R2/R1 exceeds 15 and is less than 230, high cycle life performance can be obtained. When the amount is less than 230, the coating property of the anode paste is high. The reason why the powder resistance ratio in such a range can provide high cycle life performance is considered to be: a plurality of conductive networks are formed in the negative electrode material. The reason why the coating property of the anode paste is improved is considered to be that: when the powder resistance ratio R2/R1 is in the above range, the surface state of each carbon material is optimized, and adsorption of the solvent can be appropriately suppressed. From the viewpoint of obtaining higher cycle life performance, the ratio R2/R1 is preferably 80 or more and less than 230 or 80 to 220. From the viewpoint of improving the storage property of the non-chemically converted negative electrode plate, the density of the negative electrode material is preferably less than 4.7g/cm³Further, the specific surface area ratio S2/S1 is preferably 350 or less. The reason for this is that: when the specific surface area ratio S2/S1 exceeds 350, the amount of solvent adsorbed on the surface of the carbon material becomes larger depending on the surface state of the carbon material mixed in the paste, and the amount of sulfate must be reduced to ensure coatability.

Industrial applicability

The lead acid battery according to one aspect of the present invention can be used for valve-regulated and liquid-regulated lead acid batteries, and can be suitably used as a power source for starting of automobiles, motorcycles, and the like, a storage of natural energy, an industrial power storage device such as an electric vehicle (e.g., a forklift), and the like.

Description of the symbols

1: lead-acid battery

2: negative plate

3: positive plate

4: spacer

5 a: bus bar for negative electrode

5 b: bus bar for positive electrode

6 a: negative pole

6 b: positive pole

10: electric tank

11: pole plate group

12: electrolyte solution

Claims

1. A lead-acid battery comprising a negative electrode plate and a positive electrode plate,

the carbon material contains carbon particles having a carbon number of 32μA1 st carbon material having a particle diameter of m or more and a carbon material having a particle diameter of less than 32μA2 nd carbon material having a particle diameter of m,

the content of barium sulfate in the negative electrode material is 0.2-0.7 mass%,

the density of the negative electrode material is 4.1g/cm³The above.

2. The lead-acid battery according to claim 1, wherein the ratio, R2/R1, is 80 or more and less than 230.

3. The lead-acid battery according to claim 1, wherein the ratio R2/R1 is 80 to 220.

4. A lead-acid battery according to claim 1 or 2, wherein the negative electrode material has a density of less than 4.7g/cm³。

5. The lead storage battery according to claim 3, wherein the negative electrode material has a density of less than 4.7g/cm³。

6. The lead-acid battery according to claim 4, wherein the 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, that is, S2/S1, is 350 or less.

7. The lead-acid battery according to claim 5, wherein the 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, that is, S2/S1, is 350 or less.

8. The lead-acid battery according to any one of claims 1 to 3 and 5 to 7, wherein the content of barium sulfate in the negative electrode material is 0.2 to 0.6 mass%.

9. The lead-acid battery according to claim 4, wherein the content of barium sulfate in the negative electrode material is 0.2 to 0.6 mass%.

10. The lead-acid battery according to any one of claims 1 to 3, 5 to 7 and 9, wherein the content of the 1 st carbon material in the negative electrode material is 0.05 mass% or more.

11. The lead-acid battery according to claim 4, wherein the content of the 1 st carbon material in the negative electrode material is 0.05 mass% or more.

12. The lead-acid battery according to claim 8, 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 3, 5 to 7, 9, 11 and 12, wherein the content of the 1 st carbon material in the negative electrode material is 1.5% by mass or less.

14. The lead-acid battery according to claim 4, wherein the content of the 1 st carbon material in the negative electrode material is 1.5% by mass or less.

15. The lead-acid battery according to claim 8, wherein the content of the 1 st carbon material in the negative electrode material is 1.5% by mass or less.

16. The lead-acid battery according to claim 10, wherein the content of the 1 st carbon material in the negative electrode material is 1.5% by mass or less.

17. A lead-acid battery according to any one of claims 1 to 3, 5 to 7, 9, 11, 12 and 14 to 16, wherein the content of the 2 nd carbon material in the negative electrode material is 0.1 mass% or more.

18. The lead-acid battery according to claim 4, wherein the content of the 2 nd carbon material in the negative electrode material is 0.1 mass% or more.

19. The lead-acid battery according to claim 8, wherein the content of the 2 nd carbon material in the negative electrode material is 0.1 mass% or more.

20. The lead-acid battery according to claim 10, wherein the content of the 2 nd carbon material in the negative electrode material is 0.1 mass% or more.

21. The lead-acid battery according to claim 13, wherein a content of the 2 nd carbon material in the negative electrode material is 0.1 mass% or more.

22. A lead storage battery according to any one of claims 1 to 3, 5 to 7, 9, 11, 12, 14 to 16 and 18 to 21, wherein the content of the 2 nd carbon material in the negative electrode material is 0.6% by mass or less.

23. The lead-acid battery according to claim 4, wherein the content of the 2 nd carbon material in the negative electrode material is 0.6 mass% or less.

24. The lead-acid battery according to claim 8, wherein a content of the 2 nd carbon material in the negative electrode material is 0.6 mass% or less.

25. The lead-acid battery according to claim 10, wherein a content of the 2 nd carbon material in the negative electrode material is 0.6 mass% or less.

26. The lead-acid battery according to claim 13, wherein a content of the 2 nd carbon material in the negative electrode material is 0.6 mass% or less.

27. The lead-acid battery according to claim 17, wherein a content of the 2 nd carbon material in the negative electrode material is 0.6 mass% or less.

28. A lead storage battery according to any one of claims 1 to 3, 5 to 7, 9, 11, 12, 14 to 16, 18 to 21 and 23 to 27, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

29. The lead-acid battery according to claim 4, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

30. The lead-acid battery according to claim 8, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

31. The lead-acid battery according to claim 10, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

32. The lead-acid battery according to claim 13, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

33. The lead-acid battery according to claim 17, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.

34. The lead-acid battery according to claim 22, wherein the 1 st carbon material contains at least graphite, and the 2 nd carbon material contains at least carbon black.