WO2022102422A1

WO2022102422A1 - Lead storage battery and method for producing negative electrode plate for lead storage battery

Info

Publication number: WO2022102422A1
Application number: PCT/JP2021/039780
Authority: WO
Inventors: 圭祐熊澤; 悦子伊藤; 和成安藤
Original assignee: 株式会社Ｇｓユアサ
Priority date: 2020-11-13
Filing date: 2021-10-28
Publication date: 2022-05-19

Abstract

A lead storage battery according to the present invention comprises at least one cell which is provided with an electrode plate group and an electrolyte. The electrode plate group is provided with a positive electrode plate, a negative electrode plate, and a separator which is interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate is provided with a negative electrode material which contains barium sulfate particles. When the lead storage battery is fully charged and then discharged at the 5 hour rate current to a 50% charged state, the full width at half maximum of the peak corresponding to the [211] plane of lead sulfate in an X-ray-diffraction spectrum of the negative electrode material is not less than 0.137°.

Description

Manufacturing method of lead-acid battery and negative electrode plate for lead-acid battery

The present invention relates to a lead storage battery and a method for manufacturing a negative electrode plate for a lead storage battery.

Lead-acid batteries are used for various purposes such as in-vehicle use, industrial use, and so on. The lead-acid battery includes a positive electrode plate and a negative electrode plate, a separator interposed therein, and an electrolytic solution.

The negative electrode plate for a lead storage battery includes a negative electrode material and a negative electrode collector that holds the negative electrode material. For the negative electrode plate, for example, a negative electrode paste containing a powder containing a lead oxide as a main component is filled in a negative electrode current collector and dried to produce an unchemical negative electrode plate, and the unchemical negative electrode plate is formed. It is formed by. The negative electrode paste is prepared, for example, by mixing a powder containing lead oxide as a main component, an additive if necessary, and an aqueous sulfuric acid solution. Organic shrink-proofing agents, barium sulfate and the like are used as additives. Barium sulphate has low solubility in water or aqueous sulfuric acid and is commonly used in the preparation of negative electrode pastes in powder form. Barium sulfate powder has high cohesiveness, and it is difficult to disperse it uniformly in the negative electrode paste.

Patent Document 1 is characterized in that a coagulated powder of barium sulfate is crushed in a solution containing a surfactant, and the obtained barium sulfate suspension is used as an additive for a negative electrode active material to produce a negative electrode paste for a lead storage battery. We are proposing a method for manufacturing negative electrode paste for lead-acid batteries.

Patent Document 2 prepares a reaction solution in which barium sulfate is precipitated by the reaction of barium ion and sulfate ion, a reaction solution in which the reaction solution is concentrated, or a slurry-like barium sulfate reaction solution separated by filtration thereof. Next, we propose a method for manufacturing a negative electrode plate of a lead storage battery, which comprises a process of adding this at the time of preparing a negative electrode active material paste and kneading it to prepare a negative electrode active material paste.

Japanese Patent Application Laid-Open No. 2003-257432 Japanese Unexamined Patent Publication No. 2001-332252

Barium sulfate particles become crystal nuclei of lead sulfate generated when the lead storage battery is discharged, and have the effect of suppressing the coarsening of lead sulfate. Therefore, when barium sulfate is used for the negative electrode plate, the reduction reaction from lead sulfate to lead is likely to occur during charging, so that the charge acceptability is improved and the regenerative acceptability tends to be enhanced. On the other hand, when barium sulfate is used, the lead content is relatively reduced, so that the discharge capacity tends to decrease. From the viewpoint of ensuring high regenerative acceptability while ensuring high discharge capacity, it is advantageous to uniformly disperse barium sulfate particles having a small particle size in the negative electrode electrode material. However, the smaller the particle size of the barium sulfate particles, the higher the cohesiveness. Therefore, it is actually difficult to disperse barium sulfate particles having a small particle size in a more uniform state in the negative electrode material, and the effect of sufficiently improving the regenerative acceptability has not yet been obtained.

The first aspect of the present invention is a lead storage battery.
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The half-value full width of the peak corresponding to the [211] plane of lead sulfate in the X-ray diffraction spectrum of the negative electrode material when the lead-acid battery is fully charged and then discharged to a 50% charged state with a 5-hour rate current is It relates to a lead-acid battery having a temperature of 0.137 ° or higher.

The second aspect of the present invention is a lead storage battery.
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The number of pixels of the image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron probe microanalyzer on the cross section parallel to the thickness direction of the negative electrode plate is assigned to the characteristic X-ray of Ba in the region of 200 × 400 in the X direction. Of the portion showing the intensity equal to or higher than the threshold value when the intensity of R of RGB is adjusted to the maximum value and the binarization process is performed with the intensity of 1/2 of the maximum value as the threshold value, 0.05% of the area. The present invention relates to a lead storage battery in which the number of islands having the above area ratio is one or less.

The third aspect of the present invention is a method for manufacturing a negative electrode plate for a lead storage battery.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size of the barium sulfate powder is 1 μm or less, and the average particle size is 1 μm or less.
The liquid relates to a method for manufacturing a negative electrode plate for a lead storage battery, which is an aqueous solution of sulfuric acid.

The fourth aspect of the present invention is a method for manufacturing a negative electrode plate for a lead storage battery.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size of the barium sulfate powder is 0.4 μm or less, and the average particle size is 0.4 μm or less.
The liquid relates to a method for manufacturing a negative electrode plate for a lead storage battery, which is pure water.

The regenerative acceptance of lead-acid batteries can be improved. Alternatively, it is possible to provide a negative electrode plate capable of improving the regenerative acceptance of the lead storage battery.

It is a partially cutaway perspective view which shows the appearance and the internal structure of the lead storage battery provided with the negative electrode plate obtained by the manufacturing method which concerns on one Embodiment of this invention. It is a scanning electron microscope image of the negative electrode plate when the charge state of the lead storage battery E15 of an Example is 50%. It is a scanning electron microscope image of the negative electrode plate when the charge state of the lead storage battery C5 of the comparative example is 50%. It is a process drawing for demonstrating the manufacturing method of the negative electrode plate for a lead storage battery which concerns on one Embodiment of this disclosure.

Although the novel features of the invention are described in the appended claims, the invention is further described in detail with respect to both configuration and content, in conjunction with other objects and features of the invention, with reference to the drawings below. It will be well understood.

From the viewpoint of ensuring high regenerative acceptance of lead-acid batteries, it is advantageous that barium sulfate particles having a small particle size are uniformly dispersed in the negative electrode material. However, when the particle size of the barium sulfate powder used for preparing the negative electrode slurry becomes small, it is easily affected by the interaction between the particles and easily aggregates. Even if a barium sulfate powder having a small average particle size is mixed with other components to prepare a negative electrode slurry, it is dispersed in an aggregated state. Therefore, the effect of reducing the particle size of lead sulfate generated during discharge can hardly be obtained, and it is difficult to sufficiently bring out the effect of improving the regenerative acceptability.

When barium sulfate is crushed in a solution containing a component having a surface-active action that functions as a dispersant as in Patent Document 1, the dispersibility of barium sulfate particles is improved and high regenerative acceptability can be obtained. Is expected. However, in this case, in reality, the effect of improving the regenerative acceptability is hardly obtained. It is considered that this is because the effect of improving the dispersibility of the barium sulfate particles is insufficient. In addition, since the surface of the barium sulfate particles is covered with a component having a surface-active action, the reactivity with lead ions and sulfate ions is lowered, and the lead sulfate having the barium sulfate particles as the nucleus is reduced. Inhibition of production is also considered to be a factor. In particular, when the particle size of the barium sulfate particles is small, the surface area of the barium sulfate particles covered with the surface-active component becomes relatively large, which has an effect of inhibiting the production of lead sulfate during discharge. It becomes apparent. Further, since the barium sulfate particles in the reaction solution obtained by the method of Patent Document 2 have a large variation in particle size, it is difficult to improve the regenerative acceptability even if a negative electrode plate is formed by using the reaction solution.

In view of such findings, the lead-acid battery according to each of the first aspect and the second aspect of the present invention includes at least one cell including a plate group and an electrolytic solution. The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate. The negative electrode plate comprises a negative electrode material containing barium sulfate particles.

On the first aspect, the lead sulfate [211] in the X-ray diffraction (XRD: X-ray diffraction) spectrum of the negative electrode material when the lead-acid battery is fully charged and then discharged to a 50% charge state at a 5-hour rate current. ] The half-value full width of the peak corresponding to the surface is 0.137 ° or more (hereinafter, may be referred to as condition (a)). A negative electrode plate when a lead-acid battery is fully charged and then discharged to a 50% charge state (SOC: State of charge) at a 5-hour rate current may be simply referred to as a negative electrode plate at 50% SOC.

In the lead storage battery on the second side, the number of pixels of an image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron probe microanalyzer (EPMA) in a cross section parallel to the thickness direction of the negative electrode plate is 200 × in the X direction. In the region of 400 in the Y direction (hereinafter, may be referred to as region A), the intensity of R of RGB attributed to the characteristic X-ray of Ba is adjusted to the maximum value, and the intensity of 1/2 of the maximum value is used as a threshold value. The number of islands having an area ratio of 0.05% or more of the region A is one or less among the portions showing the intensity equal to or higher than the threshold value when the binarization treatment is performed (hereinafter, referred to as condition (b)). be). An island having such an area ratio corresponds to agglomerated particles of barium sulfate particles. According to the condition (b), since the number ratio of the aggregated particles is small, the effect of suppressing the coarsening of lead sulfate during discharge is further enhanced. The area ratio of one island is, for example, 0.5% or less, and may be 0.3% or less or 0.1% or less. Islands with larger area ratios are preferably not observed (or not included) in region A. In the EPMA image, the point where the signal intensity is the highest is red (R), and as the signal intensity decreases from that point, the color shifts to a cool color system.

The negative electrode plate may satisfy both the condition (a) and the condition (b).

The negative electrode plate included in each of the lead storage batteries on the first side surface and the second side surface is mainly composed of the first step of mixing barium sulfate powder and a liquid to prepare a dispersion liquid and the dispersion liquid and lead oxide. It can be produced by a production method comprising a second step of mixing with powder to prepare a negative electrode paste. An aqueous sulfuric acid solution is used as the liquid, and the average particle size of the barium sulfate powder at this time is 1 μm or less. Pure water is used as the liquid, and the average particle size of the barium sulfate powder at this time is 0.4 μm or less.

The method for manufacturing a negative electrode plate for a lead storage battery according to the third aspect of the present invention includes a first step of mixing barium sulfate powder and a liquid to prepare a dispersion, and a powder containing the dispersion and a lead oxide as main components. A second step of mixing and preparing a negative electrode paste is provided. The average particle size of barium sulfate powder is 1 μm or less. The liquid is an aqueous sulfuric acid solution.

In the method for manufacturing a negative electrode plate for a lead storage battery according to the fourth aspect of the present invention, a first step of mixing barium sulfate powder and a liquid to prepare a dispersion liquid and a powder containing lead oxide as a main component are mixed. The second step of preparing the negative electrode paste is provided. The average particle size of barium sulfate powder is 0.4 μm or less. The liquid is pure water.

In the lead-acid battery on the first side, the crystallinity of lead sulfate generated during discharge in the negative electrode material is low. This indicates that barium sulfate particles having a small particle size are dispersed in the negative electrode material with high dispersibility. In the lead-acid battery on the second side, barium sulfate particles having a small particle size are dispersed in the negative electrode material with high dispersibility, and the ratio of aggregated particles is small. Further, according to the above-mentioned manufacturing method (manufacturing method of the third side surface and the fourth side surface, etc.), a dispersion liquid is prepared by using a sulfuric acid aqueous solution or pure water for barium sulfate powder, and this dispersion liquid is used as a negative electrode paste. Used for preparation. Barium sulfate has a high affinity for aqueous sulfuric acid. Therefore, even if barium sulfate powder having a small average particle size is added to an aqueous sulfuric acid solution and stirred, the barium sulfate particles are charged, and the van der Waals force reduces aggregation, resulting in a more uniform state in the aqueous sulfuric acid solution. Finely dispersed. By using this dispersion for preparing the negative electrode paste, it is possible to form a negative electrode plate in which barium sulfate particles having a small particle size are dispersed in the negative electrode material with high dispersibility. Therefore, in a lead-acid battery using such a negative electrode plate (lead-acid batteries on the first side surface and the second side surface, etc.), lead sulfate crystal grows on the negative electrode plate with barium sulfate particles having a small particle size as nuclei during discharge. , The coarsening of lead sulfate is suppressed. Therefore, the reduction reaction from lead sulfate to lead is likely to occur during charging, which improves charge acceptability. As a result, regenerative acceptability can be improved. In addition, since barium sulfate particles having a small particle size can be dispersed in the negative electrode material with high dispersibility, high regenerative acceptability is achieved even if the barium sulfate content per unit volume of lead, which is the negative electrode active material, is relatively low. can get. Since the ratio of lead in the negative electrode electrode material can be relatively increased, a high discharge capacity can be ensured.

Even when pure water is used to prepare the dispersion, if the average particle size of the barium sulfate powder is 0.4 μm or less, the same effect as that of the aqueous sulfuric acid solution can be obtained. It is considered that even when the barium sulfate powder is dispersed in pure water, the agglomeration of the barium sulfate particles is reduced by the van der Waals force, and the particles are finely dispersed in the sulfuric acid aqueous solution in a more uniform state.

In the above production method, unlike the case where barium sulfate powder is dispersed in a solution containing a component having a surface-active action, the surface of barium sulfate particles in the dispersion is covered with a component that inhibits the crystal growth of lead sulfate. You won't be struck. Therefore, in a lead-acid battery using a negative electrode plate obtained by the above manufacturing method (lead-acid battery on the first side surface and the second side surface, etc.), the crystal growth of lead sulfate having barium sulfate particles as nuclei is inhibited at the time of discharge. This is suppressed, and high charge acceptability can be ensured. From this point as well, high regenerative acceptance can be ensured.

In the negative electrode plate obtained by the above manufacturing method, the crystallinity of lead sulfate produced during discharge in the negative electrode electrode material is low, as described for the lead storage battery on the first side surface. Further, in the negative electrode plate obtained by the above manufacturing method, as described for the lead storage battery on the second side surface, barium sulfate particles having a small particle size are dispersed in the negative electrode electrode material with high dispersibility, and aggregated particles. The ratio of is small. The crystallinity of lead sulfate generated during discharge in the negative electrode material can be evaluated, for example, by the half-value full width of the peak corresponding to the [211] plane of lead sulfate in the X-ray diffraction spectrum. Further, the fact that the aggregation of barium sulfate particles is reduced in the negative electrode electrode material and the particles are dispersed with high dispersibility means that, for example, the characteristic X of Ba in the Ba distribution of the image obtained by analyzing the cross section of the negative electrode plate with an electron probe microanalyzer. It can be evaluated based on the strength of the line.

More specifically, in the above production method, when the preparation conditions of the dispersion liquid are changed, among the main peaks caused by lead sulfate in the XRD spectrum of the negative electrode material, the peak corresponding to the [211] plane. There is a change in the full width at half maximum of the peak, and there is no significant change in the full width at half maximum of the peak corresponding to the other planes. It was clarified that the regenerative acceptability of the lead storage battery changes according to the change in the full width at half maximum of the peak corresponding to the [211] plane, and is related to the crystallinity of lead sulfate produced during discharge. The peak corresponding to the [211] plane is observed in the range where 2θ is 28.5 ° or more and 30.5 ° or less (usually around 29.6 °).

Under the condition (a), the full width at half maximum is preferably 0.139 ° or more. In this case, since the crystallinity of lead sulfate is low, the charge acceptability is further improved, and higher regenerative acceptability can be ensured.

Under the condition (a), the full width at half maximum is preferably 0.2 ° or less. In this case, the reaction from lead to lead sulfate at the time of discharge tends to proceed smoothly, and high discharge performance can be easily obtained.

From the viewpoint of ensuring higher regenerative acceptability, the ratio of the portion exhibiting the strength equal to or higher than the threshold value to the region A is preferably 2.8% or less. In this case, the barium sulfate particles are dispersed in the negative electrode material with higher dispersibility, and the charge acceptability is enhanced, so that high regenerative acceptability can be obtained.

The content of barium sulfate particles in the negative electrode electrode material is preferably 0.5% by mass or more. In this case, the decrease in dispersibility due to the aggregation of barium sulfate particles tends to become apparent. Even in such a case, high dispersibility of barium sulfate in the negative electrode material can be ensured. Therefore, higher regenerative acceptability can be ensured.

The content of barium sulfate particles in the negative electrode electrode material is preferably 7.5% by mass or less. In this case, it is possible to secure a higher initial capacity while ensuring high regenerative acceptability.

In the negative electrode material, the average particle size of barium sulfate particles is preferably 1 μm or less. When the average particle size is in this range, the regenerative acceptability is usually likely to decrease due to the aggregation of barium sulfate particles. Even in such a case, high dispersibility of barium sulfate particles can be obtained in the negative electrode material, and high regenerative acceptability can be ensured.

In the negative electrode material, the average particle size of barium sulfate particles is, for example, 0.01 μm or more. Even when the average particle size is small as described above, barium sulfate particles can be dispersed in the negative electrode material with high dispersibility, and high regenerative acceptability can be ensured.

On the third and fourth aspects, the dispersion usually does not contain at least one selected from the group consisting of organic shrink proofing agents and surfactants. The organic shrink proofing agent has a hydrophilic portion and a hydrophobic portion, and has a surface-active action. Since the dispersion liquid does not contain a component having a surfactant action such as an organic shrinkage proofing agent or a surfactant, high charge acceptability can be obtained and high regenerative acceptability can be ensured. In addition, the organic shrink-proofing agent adhering to the surface of the barium sulfate particles at the stage of the dispersion liquid no longer has a surface-active effect when preparing the negative electrode paste, and the lead fine particles in the negative electrode electrode material are present. It is difficult to ensure high discharge performance because the effect of keeping the holes small cannot be exhibited.

In the third aspect, the density of the aqueous sulfuric acid solution at 20 ° C. is preferably 1.03 g / cm ³ or more. As the density increases, the barium sulfate particles are further charged, and the dispersibility of the barium sulfate particles in the dispersion is further improved. Therefore, higher regenerative acceptability can be ensured.

The average particle size of barium sulfate powder is, for example, 0.01 μm or more. Even when the average particle size is small as described above, barium sulfate particles can be dispersed in the dispersion liquid with high dispersibility, and high regenerative acceptability can be ensured.

The amount of barium sulfate powder is preferably 0.5 parts by mass or more with respect to 100 parts by mass of the powder containing lead oxide as a main component. In this case, the decrease in dispersibility due to the aggregation of barium sulfate particles tends to become apparent. Even in such a case, high dispersibility of barium sulfate particles can be ensured by preparing a dispersion liquid in advance using an aqueous sulfuric acid solution or pure water. Therefore, higher regenerative acceptability can be ensured.

The amount of barium sulfate powder is preferably 7 parts by mass or less with respect to 100 parts by mass of the powder containing lead oxide as a main component. In this case, it is possible to secure a higher initial capacity while ensuring high regenerative acceptability.

The content of barium sulfate in the dispersion is preferably 55% by mass or less. In this case, the dispersibility of the barium sulfate particles in the dispersion liquid is further enhanced, so that the dispersibility of the barium sulfate particles in the negative electrode paste can be further enhanced.

The lead-acid battery may be either a control valve type (sealed type) lead-acid battery or a liquid type (vent type) lead-acid battery. The control valve type lead-acid battery is also referred to as a VRLA type lead-acid battery (Valve-regulated lead-acid battery).

In the present specification, the EPMA analysis is performed on the negative electrode plate taken out from the fully charged lead-acid battery. The content and average particle size of the barium sulfate particles in the negative electrode electrode material are obtained for the negative electrode plate taken out from the lead storage battery in a fully charged state. The XRD spectrum is measured for the negative electrode material of the negative electrode plate taken out from the lead storage battery in the state of being discharged from the fully charged state to the charged state of 50% with a 5-hour rate current (SOC 50%).

(Explanation of terms)
(Electrode material)
Each electrode material of the negative electrode material and the positive electrode material is usually held in the current collector. The electrode material is a portion of the electrode plate excluding the current collector. Members such as mats and pacing papers may be attached to the electrode plate. Since such a member (also referred to as a sticking member) is used integrally with the plate, it is included in the plate. When the electrode plate includes a sticking member (mat, pacing paper, etc.), the electrode material is a portion of the electrode plate excluding the current collector and the sticking member.

Among the positive electrode plates, the clad type positive electrode plate has a plurality of porous tubes, a core metal inserted in each tube, a current collecting portion for connecting the plurality of core metals, and a core metal inserted. It is provided with a positive electrode material filled in a tube and a collective punishment for connecting a plurality of tubes. In the clad type positive electrode plate, the positive electrode electrode material is a portion of the electrode plate excluding the tube, the core metal, the current collector, and the collective punishment. In the clad type positive electrode plate, the core metal and the current collector may be collectively referred to as a positive electrode current collector.

(Average particle size of barium sulfate particles and barium sulfate powder)
The average particle size of the barium sulfate particles and the average particle size of the barium sulfate powder are both the average particle size of the primary particles of the barium sulfate particles. The average particle size of barium sulfate particles and barium sulfate powder is the particle size corresponding to 50% of the integrated value (median size (D50)) in the volume-based particle size distribution measured by a laser diffraction or scattering type particle size distribution measuring device. ).

(Pure water)
Pure water is water having an electrical resistivity of 0.1 MΩ · cm or more and 1.5 MΩ · cm or less. Pure water includes, for example, water obtained by at least one treatment selected from the group consisting of ion exchange, distillation, and reverse osmosis membrane filtration.

(Fully charged)
The fully charged state of a liquid lead-acid battery is defined by the definition of JIS D 5301: 2019. More specifically, in a water tank at 25 ° C ± 2 ° C, charging is performed every 15 minutes with a current (A) 0.2 times the value described as the rated capacity (value whose unit is Ah). The state in which the lead-acid battery is charged is regarded as a fully charged state until the terminal voltage (V) of No. 1 or the electrolyte density converted into temperature at 20 ° C. shows a constant value with three valid digits three times in a row. In the case of a control valve type lead-acid battery, the fully charged state is 0.2 times the current (value with Ah as the unit) described in the rated capacity in the air tank at 25 ° C ± 2 ° C (the unit is Ah). In A), constant current constant voltage charging of 2.23 V / cell is performed, and the charging current at the time of constant voltage charging is 0.005 times the value (value with the unit being Ah) described in the rated capacity (A). When it becomes, charging is completed.

A fully charged lead-acid battery is a fully charged lead-acid battery. The lead-acid battery may be fully charged after the chemical conversion, immediately after the chemical conversion, or after a lapse of time from the chemical conversion (for example, after the chemical conversion, the lead-acid battery in use (preferably at the initial stage of use) is fully charged. May be).

Batteries in the early stages of use are batteries that have not been used for a long time and have hardly deteriorated.

Hereinafter, reference is made to a drawing regarding a method for manufacturing a negative electrode plate for a lead storage battery according to an embodiment of the present invention, a negative electrode plate obtained by this manufacturing method, and a lead storage battery provided with the negative electrode plate or a lead storage battery according to an embodiment of the present invention. I will explain more specifically while doing so. However, the present invention is not limited to the following embodiments.

[Lead-acid battery]
Lead-acid batteries include at least one cell with a group of plates and an electrolyte. The electrode plate group includes a negative electrode plate, a positive electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.

(Negative electrode plate)
The negative electrode plate comprises a negative electrode material containing barium sulfate particles. The negative electrode plate usually includes a negative electrode current collector in addition to the negative electrode material.

For the negative electrode plate at SOC 50%, the full width at half maximum of the peak corresponding to the [211] plane of lead sulfate in the XRD spectrum of the negative electrode material may be 0.137 ° or more. Barium sulfate particles having a small particle size are dispersed in the negative electrode material with high dispersibility, so that the crystallinity of lead sulfate generated during discharge is lowered. As a result, the reduction reaction from lead sulfate to lead easily proceeds during charging, and the charge acceptability is improved, so that high regenerative acceptability can be obtained. From the viewpoint of ensuring higher regenerative acceptability, the full width at half maximum of the peak is preferably 0.139 ° or more. From the viewpoint that the reaction from lead to lead sulfate during discharge easily proceeds smoothly and high discharge performance can be easily ensured, the full width at half maximum of the above peak is preferably 0.2 ° or less, and 0.19 ° or less. More preferred.

The full width at half maximum of the peak may be 0.137 ° or more (or 0.139 ° or more) 0.2 ° or less, or 0.137 ° or more (or 0.139 ° or more) 0.19 ° or less. ..

Regarding the condition (b), in the image showing the Ba distribution of EPMA, the number of islands having an area ratio of 0.05% or more of the region A among the portions showing the intensity equal to or higher than the threshold value is 1 or less, and 1 It is preferably less than the number. Since the number ratio of the agglomerated particles is small, the effect of suppressing the coarsening of lead sulfate during discharge is further enhanced. Since the reduction reaction from lead sulfate to lead easily proceeds during charging, charge acceptability is improved, so that high regenerative acceptability can be obtained.

From the viewpoint of ensuring higher regenerative acceptability, the ratio of the portion exhibiting the intensity equal to or higher than the threshold value to the region A is preferably 2.8% or less, and more preferably 2.5% or less. , 1.0% or less is more preferable. In this case, the barium sulfate particles are dispersed in the negative electrode material with higher dispersibility, and the charge acceptability is enhanced, so that high regenerative acceptability can be obtained.

(Negative electrode current collector)
The negative electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding processing and punching processing. It is preferable to use a grid-shaped current collector as the negative electrode current collector because it is easy to support the negative electrode material.

The lead alloy used for the negative electrode current collector may be any of Pb—Sb-based alloys, Pb-Ca-based alloys, and Pb-Ca—Sn-based alloys. The lead or lead alloy may further contain, as an additive element, at least one selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like. The negative electrode current collector may include a surface layer. The composition of the surface layer and the inner layer of the negative electrode current collector may be different. The surface layer may be formed on a part of the negative electrode current collector. The surface layer may be formed on the selvage portion of the negative electrode current collector. The surface layer of the selvage may contain Sn or Sn alloy.

(Negative electrode material)
In addition to barium sulfate particles, the negative electrode electrode material further contains a negative electrode active material (specifically, lead or lead sulfate) that develops a capacity by a redox reaction. The negative electrode active material in the charged state is spongy lead. The negative electrode material may contain other additives. Other additives include carbonaceous materials, organic shrink proofing agents, reinforcing materials, and other known additives.

In the negative electrode material, the average particle diameter (D50) of the barium sulfate particles is 1 μm or less, may be 0.7 μm or less or 0.6 μm or less, and may be 0.4 μm or less or 0.3 μm or less. good. When the average particle size is such a small size, the barium sulfate particles are usually likely to aggregate and the regenerative acceptability is likely to decrease. However, even in such a case, the barium sulfate particles can be dispersed in the negative electrode material with high dispersibility, so that high regenerative acceptability can be obtained. The lower limit of the average particle size of barium sulfate particles is not particularly limited. The average particle size of barium sulfate particles is, for example, 0.01 μm or more.

From the viewpoint of ensuring higher regenerative acceptability, the maximum particle size of barium sulfate particles is, for example, 2.5 μm or less, preferably 2 μm or less. The maximum particle size of the barium sulfate particles is the maximum value of the primary particle size of the barium sulfate particles contained in the negative electrode electrode material.

The content of barium sulfate particles in the negative electrode electrode material is, for example, 0.1% by mass or more, preferably 0.5% by mass or more or 1% by mass or more. When the content of the barium sulfate particles is 0.5% by mass or more, the decrease in dispersibility due to the aggregation of the barium sulfate particles is usually likely to become apparent, but even in this case, the negative electrode plate is formed by using the dispersion liquid. By manufacturing, high dispersibility of barium sulfate particles in the negative electrode electrode material can be ensured. The content of barium sulfate particles in the negative electrode electrode material is, for example, 7.5% by mass or less, preferably 5.3% by mass or less. In this case, a high initial capacity can be secured.

The content of barium sulfate particles in the negative electrode electrode material is 0.1% by mass or more and 7.5% by mass or less (or 5.3% by mass or less), 0.5% by mass or more and 7.5% by mass or less (or 5). It may be 1.3% by mass or less), or 1% by mass or more and 7.5% by mass or less (or 5.3% by mass or less).

Examples of carbonaceous materials include carbon black, graphite (artificial graphite, natural graphite, etc.), hard carbon, soft carbon, and the like. The negative electrode material may contain one kind of carbonaceous material, or may contain two or more kinds of carbonaceous material.

The content of the carbonaceous material in the negative electrode material is, for example, 0.1% by mass or more. The content of the carbonaceous material in the negative electrode material is, for example, 3.5% by mass or less.

Examples of the organic shrinkage proofing agent include lignin, lignin sulfonic acid or a salt thereof, and a synthetic organic shrinkage proofing agent (formaldehyde condensate of phenol compound, etc.). The negative electrode electrode material may contain one kind of organic shrinkage proofing agent, or may contain two or more kinds of organic shrinkage proofing agents.

The content of the organic shrinkage proofing agent in the negative electrode electrode material is, for example, 0.01% by mass or more. The content of the organic shrinkage barrier in the negative electrode electrode material is, for example, 1.2% by mass or less.

Examples of the reinforcing material include fibers (inorganic fibers, organic fibers, etc.). Examples of the resin constituting the organic fiber include at least one selected from the group consisting of an acrylic resin, a polyolefin resin, a polyester resin, and a cellulose compound (cellulose, rayon, etc.).

The content of the reinforcing material in the negative electrode electrode material is, for example, 0.03% by mass or more. The content of the reinforcing material in the negative electrode electrode material is, for example, 0.6% by mass or less.

(Analysis of negative electrode plate, negative electrode material, or its constituents)
Hereinafter, procedures for measuring the XRD spectrum and EPMA analysis of the negative electrode material, measuring and quantitatively analyzing the particle size of barium sulfate particles in the negative electrode material, and quantitatively analyzing the organic shrinkage proofing agent, carbonaceous material, and reinforcing material will be described. The XRD spectrum is performed using a negative electrode material taken from a negative electrode plate taken out from a lead storage battery in a state of being discharged to SOC 50% at a rate current of 5 hours from a fully charged state. Analysis or measurement other than the XRD spectrum is performed using a negative electrode plate taken out from a fully charged lead-acid battery or a negative electrode electrode material taken from this negative electrode plate.

《Sample preparation》
(Sample A)
A fully charged lead-acid battery is discharged to SOC 50% at a 5-hour rate current as defined in JIS D5301: 2019. Dismantle the lead-acid battery immediately after discharge to obtain the negative electrode plate to be analyzed. The obtained negative electrode plate is washed with water, and the electrolytic solution is removed from the negative electrode plate. Wash with water by pressing the pH test paper against the surface of the negative electrode plate washed with water until it is confirmed that the color of the test paper does not change. However, the time for washing with water shall be within 2 hours. The negative electrode plate washed with water is dried at 60 ± 5 ° C. for about 6 hours in a reduced pressure environment. If the negative electrode plate contains a sticking member after drying, the sticking member is removed from the negative electrode plate by peeling. Next, by separating the negative electrode material from the negative electrode plate, a sample for XRD spectrum measurement (hereinafter referred to as sample A) is obtained.

(Sample B)
Disassemble the fully charged lead-acid battery to obtain the negative electrode plate to be analyzed. The negative electrode plate is washed with water and dried in the same manner as in the procedure of sample A except that the obtained negative electrode plate is used. If the negative electrode plate contains a sticking member after drying, the sticking member is removed from the negative electrode plate by peeling. The entire obtained negative electrode plate is impregnated with epoxy resin and cured. In the cured state, a predetermined portion is cut in the thickness direction of the negative electrode plate, and the cut cross section (cross section parallel to the thickness direction) is polished. In this way, sample B for EPMA analysis is prepared.

(Sample C)
Disassemble the fully charged lead-acid battery to obtain the negative electrode plate to be analyzed. Sample C is obtained by the same procedure as in the case of sample A except that the obtained negative electrode plate is used. Sample C is pulverized as needed and subjected to analysis.

<< XRD spectrum measurement >>
Using the pulverized sample A, the XRD spectrum of the negative electrode material is measured under the following conditions, and the full width at half maximum (°) of the peak corresponding to the [211] plane of lead sulfate is obtained.
Equipment used: Fully automatic multipurpose X-ray diffractometer manufactured by RIGAKU Smart Lab (horizontal goniometer θ-θ type, Cu-Kα ray)
Analysis software: Integrated powder X-ray analysis software PDXL2 manufactured by RIGAKU
Applied voltage: 40kV
Applied current: 30mA
Sample holder: Circular holder with a diameter of 18 mm Standard material: Silicon

<< EPMA analysis >>
Using sample B, the distribution of Ba in a cross section parallel to the thickness direction of the negative electrode plate is analyzed by EPMA (electron microanalyzer EPMA-1600 manufactured by Shimadzu Corporation) to obtain an image having a resolution of 250 dpi or more and 350 dpi or less. In the region (region A) where the number of pixels of the obtained image is 200 in the X direction × 400 in the Y direction, the intensity of RGB R attributed to the characteristic X-ray of Ba is adjusted to the maximum value (specifically, 255). Then, the binarization process is performed by the image processing software with the intensity of 1/2 of the maximum value (= 255/2 ≈128) as a threshold value. In the binarized image, the ratio (%) of the portion showing the intensity equal to or higher than the threshold value in the region A is obtained. This ratio is the ratio (%) of the area of the portion showing the intensity equal to or higher than the threshold value to the area of the region A. Further, the number of islands having an area ratio of 0.05% or more of the region A is measured in the binarized image. JTrim (ver. 1.53c) is used as the image processing software.

<< Quantification of organic shrinkage agent >>
The pulverized sample C is immersed in a 1 mol / L NaOH aqueous solution to extract an organic shrinkage proofing agent. The insoluble component is removed by filtration from the extracted NaOH aqueous solution containing the organic shrinkage proofing agent, and the filtrate (hereinafter, also referred to as filtrate D) is recovered.

A predetermined amount of the filtrate D is measured, desalted, concentrated, and dried to obtain an organic shrink-proofing agent powder (hereinafter, also referred to as sample E). Desalting is performed using a desalting column, by passing the filtrate D through an ion exchange membrane, or by placing the filtrate D in a dialysis tube and immersing it in distilled water.

It constitutes an infrared spectral spectrum of sample E, an ultraviolet visible absorption spectrum of a solution obtained by dissolving sample E in distilled water or the like, an NMR spectrum of a solution obtained by dissolving sample E in a solvent such as heavy water, or a substance. The organic shrink-proofing agent is specified by combining the information obtained from the thermal decomposition GC-MS or the like which can obtain the information of the individual compounds.

Measure the ultraviolet-visible absorption spectrum of the filtrate D. The content of the organic shrinkage barrier in the negative electrode material is quantified from the spectral intensity, the calibration curve prepared in advance, the measured amount of the filtrate D, and the mass of the sample C. If the structural formula of the organic shrinkage proofing agent to be analyzed cannot be specified exactly and the calibration curve of the same organic shrinkage proofing agent cannot be used, an ultraviolet-visible absorption spectrum or an infrared spectroscopic spectrum similar to that of the organic shrinkage proofing agent to be analyzed, A calibration curve is prepared using an available organic shrink-proofing agent showing an NMR spectrum or the like.

<< Quantification of carbonaceous materials, barium sulfate, and reinforcing materials >>
To 10 g of the crushed sample C, 50 mL of nitric acid having a concentration of 20% by mass is added and heated for about 20 minutes to dissolve the lead component as lead ions. Next, the obtained solution is filtered to separate solids such as carbonaceous material and barium sulfate.

After the obtained solid content is dispersed in water to form a dispersion liquid, the reinforcing material is recovered from the dispersion liquid using a sieve. The reinforcing material is washed with water and dried, and the mass is measured. The ratio (percentage) of the mass of the dried product to the mass of the sample C is obtained. This ratio corresponds to the amount of reinforcing material in the negative electrode material.

After removing the reinforcing material, the dispersion liquid is suction-filtered using a membrane filter whose mass has been measured in advance, and the membrane filter is dried together with the filtered sample in a dryer at 110 ° C. ± 5 ° C. The obtained sample is a mixed sample of a carbonaceous material and barium sulfate (hereinafter, also referred to as sample F). The mass of the sample F (M _m ) is measured by subtracting the mass of the membrane filter from the total mass of the sample F and the membrane filter after drying. Then, the dried sample F is placed in a crucible together with a membrane filter and incinerated at 1300 ° C. or higher. The remaining residue is barium oxide. The mass of barium oxide is converted into the mass of barium sulfate to obtain the mass of barium sulfate ( _MB ). The mass of the carbonaceous material is calculated by subtracting the mass MB from the mass _M _m .

<< Particle size of barium sulfate particles >>
A predetermined amount of sample F is placed in a crucible and heated at 500 ° C. in an oxygen atmosphere to convert the carbonaceous material into carbon dioxide and remove it. As a result, barium sulfate is recovered as a residue. The recovered barium sulfate (sample G) is used to measure the average particle size and the maximum particle size of the barium sulfate particles. The average particle size and the maximum particle size of the barium sulfate particles are measured by a laser diffraction type particle size distribution measuring device. As the laser diffraction type particle size distribution measuring device, a master sizer 3000 manufactured by Malvern Panasonic is used. The average particle size of barium sulfate particles was obtained by adding sample G to an aqueous solution of sodium hexametaphosphate (NaHMP) (NaHMP concentration: 0.05% by mass) and performing ultrasonic dispersion for 1 minute. Is measured using.

(Manufacturing method of negative electrode plate)
Hereinafter, a method for manufacturing a negative electrode plate for a lead storage battery will be described more specifically. The negative electrode plate (for example, a negative electrode plate satisfying at least one of the conditions (a) and (b)) can be manufactured by using a dispersion liquid in which barium sulfate powder is dispersed in a specific liquid in advance.

The method for manufacturing a negative electrode plate for a lead storage battery includes a first step of preparing a dispersion liquid and a second step of preparing a negative electrode paste. The manufacturing method usually further includes a third step of manufacturing a negative electrode plate using a negative electrode paste. Hereinafter, each step will be described in more detail.

(First step)
In the first step, barium sulfate powder and a liquid are mixed to prepare a dispersion. As the liquid, an aqueous sulfuric acid solution or pure water is used.

The average particle size (D50) of the barium sulfate powder is 1 μm or less, may be 0.7 μm or less or 0.6 μm or less, and may be 0.4 μm or less or 0.3 μm or less. When an aqueous sulfuric acid solution is used as the liquid, if the average particle size of the barium sulfate powder is 1 μm or less, the effect of improving the regenerative acceptability can be obtained. When pure water is used as the liquid, if the average particle size of the barium sulfate powder is 0.4 μm or less, the effect of improving the regenerative acceptability can be obtained. The lower limit of the average particle size of barium sulfate powder is not particularly limited. The average particle size of barium sulfate powder is, for example, 0.01 μm or more. The average particle size of barium sulfate powder is the average particle size of barium sulfate powder as a raw material used for preparing a dispersion.

From the viewpoint of ensuring higher regenerative acceptability, the maximum particle size of barium sulfate powder is, for example, 2.5 μm or less, preferably 2 μm or less. The maximum particle size of barium sulfate powder is the maximum value of the primary particle size of barium sulfate powder as a raw material used for preparing a dispersion.

The average particle size and maximum particle size of barium sulfate powder can be measured according to the case of the average particle size and maximum particle size of barium sulfate particles using barium sulfate powder as a raw material used for preparing a dispersion as a sample.

The density of the aqueous sulfuric acid solution may be larger than 1 g / cm ³ . The density of the aqueous sulfuric acid solution is preferably 1.03 g / cm ³ or more. In this case, as the density increases, the barium sulfate particles are further charged, and the dispersibility of the barium sulfate particles in the dispersion is further improved. Therefore, higher regenerative acceptability can be ensured. The higher the density of the aqueous sulfuric acid solution, the higher the regenerative acceptability tends to be. Therefore, the upper limit of the density of the aqueous sulfuric acid solution is not particularly limited, and may be, for example, 1.4 g / cm ³ or less. The density of the aqueous sulfuric acid solution is the density at 20 ° C.

The dispersion liquid is obtained by mixing barium sulfate powder and a liquid. The mixing method is not particularly limited. For example, a known stirrer or mixer may be used. Mixing may be performed using a crusher such as a ball mill. However, since the barium sulfate powder has a relatively high affinity for the aqueous sulfuric acid solution or pure water, the barium sulfate powder is relatively easy to disperse in the aqueous sulfuric acid solution or pure water. Therefore, barium sulfate particles can be dispersed in a sulfuric acid aqueous solution or pure water with high dispersibility by using a stirrer or a mixer without using a crusher or the like.

From the viewpoint of more effectively suppressing the coarsening of lead sulfate generated during discharge in a lead storage battery, the dispersion liquid obtained in the first step comprises a component having a surfactant action (organic shrink proofing agent and a surfactant). It is desirable not to include at least one selected from the group). In particular, it is desirable to mix the barium sulfate powder and the liquid in the absence of a component having a surface-active action. When a component having a surface-active action is added to the dispersion liquid prior to mixing with the powder containing lead oxide as a main component, and the obtained dispersion liquid is mixed with the powder containing lead oxide as a main component. Is not intended to be excluded. However, from the viewpoint of ensuring higher regenerative acceptability, when a component having a surfactant action is added to the negative electrode paste, it is preferable to add it separately from the dispersion liquid.

The barium sulfate powder and the liquid can be mixed at a temperature at which the liquid does not solidify, and may be performed at, for example, 10 ° C. or higher, or 20 ° C. or higher. The mixing can be carried out, for example, at a temperature of 60 ° C. or lower, and may be carried out at 40 ° C. or lower.

The barium sulfate powder and the liquid may be mixed at 10 ° C. or higher (or 20 ° C. or higher) at 60 ° C. or lower, or at 10 ° C. or higher (or 20 ° C. or higher) at 40 ° C. or lower.

The barium sulfate powder and the liquid may be mixed in an atmosphere of an inert gas (nitrogen gas, etc.) or in an atmospheric atmosphere.

The barium sulfate powder and the liquid may be mixed under reduced pressure or at atmospheric pressure.

The mixing time of barium sulfate powder and liquid is not particularly limited, and is adjusted according to the mixing scale, mixing method, and the like.

The content of barium sulfate (that is, barium sulfate particles) in the dispersion is preferably 55% by mass or less, more preferably 40% by mass or less, and may be 30% by mass or less or 25% by mass or less. When the content of barium sulfate is in such a range, the dispersibility of the barium sulfate particles in the dispersion liquid is further enhanced, so that the dispersibility of the barium sulfate particles in the negative electrode paste can be further enhanced. The content of barium sulfate in the dispersion is, for example, 0.1% by mass or more, and may be 1% by mass or more or 5% by mass or more.

The content of barium sulfate in the dispersion is 0.1% by mass or more and 55% by mass or less (or 40% by mass or less), 0.1% by mass or more and 30% by mass or less (or 25% by mass or less), 1% by mass. 55% by mass or less (or 40% by mass or less), 1% by mass or more and 30% by mass or less (or 25% by mass or less), 5% by mass or more and 55% by mass or less (or 40% by mass or less), or 5% by mass or more. It may be 30% by mass or less (or 25% by mass or less).

In the first step, additives may be used if necessary. However, it is preferable not to use the additive so that the additive does not adhere to the surface of the barium sulfate particles and inhibit the crystal formation of lead sulfate during discharge.

(Second step)
In the second step, a negative electrode paste is prepared by mixing the dispersion liquid and the powder containing lead oxide as a main component. If necessary, an additive may be mixed with the dispersion liquid and the powder containing lead oxide as a main component. Examples of the additive include other additives described for the negative electrode material. By adding an organic shrinkage proofing agent separately from the dispersion liquid, it is possible to reduce the hindrance of crystal growth of lead sulfate having barium sulfate particles as nuclei during discharge, and effectively exert the shrinkage proofing effect of the organic shrinkage proofing agent. Can be made to.

The order of mixing is not particularly limited. For example, all components may be mixed at once, some components may be mixed in advance, and the remaining components may be further mixed. For example, components other than the dispersion liquid (for example, a powder containing a lead oxide as a main component, a carbonaceous material, an organic shrink-proofing agent and a reinforcing material) may be mixed in advance, and the obtained mixture may be mixed with the dispersion liquid. In addition to the dispersion liquid, a liquid component (such as at least one of pure water and an aqueous sulfuric acid solution) may be used for mixing. For example, components other than the dispersion liquid may be mixed in advance, pure water may be added and further mixed, and a dispersion liquid using a sulfuric acid aqueous solution may be added and further mixed. Further, components other than the dispersion liquid may be mixed in advance, a dispersion liquid using pure water may be added and further mixed, and a sulfuric acid aqueous solution may be added and further mixed.

Mixing is not particularly limited and can be performed using, for example, a kneader.

Mixing can be performed at, for example, 10 ° C or higher, and may be performed at 20 ° C or higher. Mixing may be performed, for example, at 40 ° C. or lower.

Mixing can be done in an atmospheric atmosphere. Mixing is usually done under atmospheric pressure.

The powder containing lead oxide as the main component contains lead monoxide as lead oxide. The proportion of lead oxide in the powder containing lead oxide as a main component is more than 50% by mass, and usually 70% by mass or more. The powder containing lead oxide as a main component may contain only lead monoxide powder. Further, the powder containing lead oxide as a main component may contain other components such as lead powder in addition to the lead oxide powder. The ratio of other components to the powder containing lead oxide as a main component is usually 30% by mass or less. Powder containing lead oxide as a main component is also generally called "lead powder". As the powder containing lead oxide as a main component, general lead powder used for producing an electrode material for a lead storage battery may be used. The negative electrode active material in the charged state is spongy lead.

The mixing ratio of the dispersion liquid and the powder containing lead oxide as a main component is such that the amount of barium sulfate (or barium sulfate powder) is 0.1 part by mass with respect to 100 parts by mass of the powder containing lead oxide as a main component. As mentioned above, it is preferably adjusted to be 0.5 parts by mass or more or 1 part by mass or more. When the amount of barium sulfate is 0.5 parts by mass or more, the decrease in dispersibility due to the aggregation of barium sulfate particles is usually likely to become apparent, but even in this case, the negative electrode material can be obtained by using the dispersion liquid. High dispersibility of barium sulfate particles in the inside can be ensured. The mixing ratio of the dispersion liquid and the powder containing lead oxide as a main component is such that the amount of barium sulfate (or barium sulfate powder) is 7 parts by mass with respect to 100 parts by mass of the powder containing lead oxide as a main component. Hereinafter, it is preferably adjusted to be 5 parts by mass or less. In this case, a high initial capacity can be secured. The mixing ratio of the dispersion liquid and the powder containing lead oxide as a main component is adjusted so that the content of barium sulfate particles in the negative electrode electrode material is within the above range.

The amount of barium sulfate with respect to 100 parts by mass of the powder containing lead oxide as a main component is 0.1 part by mass or more and 7 parts by mass or less (or 5 parts by mass or less), and 0.5 parts by mass or more and 7 parts by mass or less (or 5). It may be 1 part by mass or less) or 1 part by mass or more and 7 parts by mass or less (or 5 parts by mass or less).

Examples of the carbonaceous material include carbonaceous materials exemplified for the negative electrode electrode material. The negative electrode paste may contain one kind of carbonaceous material, or may contain two or more kinds of carbonaceous materials.

The amount of the carbonaceous material is, for example, 0.1 part by mass or more with respect to 100 parts by mass of the powder containing lead oxide as a main component. The amount of the carbonaceous material is, for example, 3.5 parts by mass or less with respect to 100 parts by mass of the powder containing lead oxide as a main component.

Examples of the organic shrinkage proofing agent include the organic shrinkage proofing agent exemplified for the negative electrode electrode material. The negative electrode paste may contain one kind of organic shrinkage proofing agent, or may contain two or more kinds.

The amount of the organic shrinkage proofing agent is, for example, 0.01 part by mass or more with respect to 100 parts by mass of the powder containing lead oxide as a main component. The amount of the organic shrink proofing agent is, for example, 1.2 parts by mass or less with respect to 100 parts by mass of the powder containing lead oxide as a main component.

Examples of the reinforcing material include the reinforcing material exemplified for the negative electrode electrode material.

The amount of the reinforcing material is, for example, 0.03 part by mass or more with respect to 100 parts by mass of the powder containing lead oxide as a main component. The amount of the reinforcing material is, for example, 0.6 parts by mass or less with respect to 100 parts by mass of the powder containing lead oxide as a main component.

(Third step)
In the third step, a negative electrode plate is produced using the negative electrode paste prepared in the second step. More specifically, a negative electrode current collector is filled with a negative electrode paste, and aged and dried to produce an unchemicald negative electrode plate. Next, the negative electrode plate is formed by forming the unchemical negative electrode plate. The negative electrode plate to be formed includes a negative electrode material and a negative electrode current collector that holds the negative electrode material. For the negative electrode current collector, the description of the negative electrode plate of the lead storage battery can be referred to.

In the aging step, it is preferable to ripen the unchemical negative electrode plate at a temperature higher than room temperature (for example, 20 ° C. or higher and 35 ° C. or lower) and high humidity.

Chemical formation can be performed by charging the electrode plate group in a state where the electrode plate group including the unchemical negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group. The formation produces spongy lead.

(Positive plate)
As the positive electrode plate of the lead storage battery, either a paste type or a clad type positive electrode plate may be used. The paste type positive electrode plate includes a positive electrode current collector and a positive electrode material. The configuration of the clad type positive electrode plate is as described above.

The positive electrode current collector may be formed by casting lead (Pb) or a lead alloy, or may be formed by processing a lead sheet or a lead alloy sheet. Examples of the processing method include expanding processing and punching processing. It is preferable to use a grid-shaped current collector as the positive electrode current collector because it is easy to support the positive electrode material.

Examples of the lead alloy used for the positive electrode current collector include Pb-Sb-based alloys, Pb-Ca-based alloys, and Pb-Ca-Sn-based alloys. The positive electrode current collector may include a surface layer. The composition of the surface layer and the inner layer of the positive electrode current collector may be different. The surface layer may be formed on a part of the positive electrode current collector. The surface layer may be formed only on the lattice portion, the ear portion, or the frame bone portion of the positive electrode current collector.

The positive electrode material contained in the positive electrode plate contains a positive electrode active material (lead dioxide or lead sulfate) that develops a capacity by a redox reaction. The positive electrode material may contain other additives (reinforcing material, etc.), if necessary.

Examples of the reinforcing material for the additive include fibers (inorganic fibers, organic fibers (organic fibers formed of the resin exemplified for the reinforcing material of the negative electrode electrode material, etc.)).

The unchemical paste type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste, aging and drying. The positive electrode paste is prepared by kneading a powder containing lead oxide as a main component, an additive, water, and sulfuric acid. In the unchemical clad type positive electrode plate, a porous tube into which a core metal connected by a current collector is inserted is filled with a slurry containing components of a positive electrode material or a powder containing lead oxide as a main component. , Formed by joining multiple tubes in a collective punishment. Then, a positive electrode plate is obtained by forming these unchemical positive electrode plates. As the powder containing lead oxide as a main component, for example, the powder containing lead oxide as a main component described for the negative electrode paste is used.

Chemical formation can be performed by charging the electrode plate group in a state where the electrode plate group including the unchemical positive electrode plate is immersed in the electrolytic solution containing sulfuric acid in the electric tank of the lead storage battery. However, the chemical formation may be performed before assembling the lead-acid battery or the electrode plate group.

(Pole plate group)
The electrode plate group includes at least one positive electrode plate, at least one negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. When the electrode plate group includes two or more negative electrode plates, the negative electrode plate (or the negative electrode obtained by the above manufacturing method) in which at least one negative electrode plate satisfies at least one of the above conditions (a) and (b) is satisfied. It may be a board). From the viewpoint of easily ensuring higher regenerative acceptability, 50% or more (preferably 80% or more) of the number of negative electrode plates included in the electrode plate group satisfies at least one of the above conditions (a) and (b). It is preferable that the negative electrode plate is satisfied (or the negative electrode plate obtained by the above-mentioned manufacturing method). Among the negative electrode plates included in the electrode plate group, the ratio of the number of negative electrode plates (or negative electrode plates obtained by the above manufacturing method) satisfying at least one of the above conditions (a) and (b) is 100%. It is as follows. All of the negative electrode plates included in the electrode plate group may be negative electrode plates (or negative electrode plates obtained by the above manufacturing method) that satisfy at least one of the above conditions (a) and (b).

The lead-acid battery may be provided with one electrode plate group or two or more lead-acid batteries. When the lead storage battery includes two or more electrode plate groups, at least one electrode plate group is obtained by a negative electrode plate (or the above-mentioned manufacturing method) satisfying at least one of the above conditions (a) and (b). It suffices to have a negative electrode plate). From the viewpoint of facilitating higher regenerative acceptance, the electrode plate group has the above-mentioned conditions (a) and (b) in 50% or more (preferably 80% or more) of the number of electrode plate groups contained in the lead storage battery. ) Satisfying at least one of the negative electrode plates (or the negative electrode plate obtained by the above-mentioned manufacturing method) is preferably provided. Percentage of the electrode plate group including the negative electrode plate (or the negative electrode plate obtained by the above manufacturing method) satisfying at least one of the above conditions (a) and (b) among the electrode plate groups included in the lead storage battery. Is 100% or less. It is preferable that all of the electrode plates included in the lead storage battery include a negative electrode plate (or a negative electrode plate obtained by the above manufacturing method) that satisfies at least one of the above conditions (a) and (b). ..

(Electrolytic solution)
The electrolytic solution is an aqueous solution containing sulfuric acid. The electrolytic solution may further contain at least one selected from the group consisting of Na ion, Li ion, Mg ion, and Al ion. The electrolytic solution may be gelled if necessary.

The specific gravity of the electrolytic solution at 20 ° C. is, for example, 1.10 or more. The specific gravity of the electrolytic solution at 20 ° C. may be 1.35 or less. It should be noted that these specific gravities are values for the electrolytic solution of the lead-acid battery which has already been used and is in a fully charged state.

The methods for manufacturing the lead-acid battery according to the first side surface and the second side surface of the present invention and the negative electrode plate for the lead storage battery according to the third side surface and the fourth side surface are summarized below.

(1) Lead-acid battery
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The half-value full width of the peak corresponding to the [211] plane of lead sulfate in the X-ray diffraction spectrum of the negative electrode material when the lead-acid battery is fully charged and then discharged to a 50% charged state with a 5-hour rate current is A lead-acid battery having a temperature of 0.137 ° or higher (sometimes referred to as condition (a)).

(2) In the above (1), the full width at half maximum may be 0.139 ° or more.

(3) In the above (1) or (2), the full width at half maximum may be 0.2 ° or less or 0.19 ° or less.

(4) In any one of the above (1) to (3), the number of pixels of an image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron beam microanalyzer on a cross section parallel to the thickness direction of the negative electrode plate is X. When the intensity of R of RGB attributed to the characteristic X-rays of Ba is adjusted to the maximum value in the region of direction 200 × direction 400 and binarized with the intensity of 1/2 of the maximum value as a threshold value. The ratio of the portion exhibiting the intensity equal to or higher than the threshold value to the region may be 2.8% or less, 2.5% or less, or 1.0% or less.

(5) In the above (4), the number of islands having an area ratio of 0.05% or more of the region may be one or less (sometimes referred to as condition (b)) in the portion. ..

(6) Lead-acid battery
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The number of pixels of the image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron probe microanalyzer on the cross section parallel to the thickness direction of the negative electrode plate is assigned to the characteristic X-ray of Ba in the region of 200 × 400 in the X direction. Of the portion showing the intensity equal to or higher than the threshold value when the intensity of R of RGB is adjusted to the maximum value and the binarization process is performed with the intensity of 1/2 of the maximum value as the threshold value, 0.05% of the area. A lead storage battery in which the number of islands having the above area ratio is one or less (condition (b)).

(7) In the above (6), the ratio of the portion to the region may be 2.8% or less, 2.5% or less, or 1.0% or less.

(8) In any one of the above (5) to (7), the area ratio of one island may be 0.5% or less, 0.3% or less, or 0.1% or less.

(9) In any one of the above (5) to (8), the number of the islands may be less than one.

(10) In any one of the above (1) to (9), the content of the barium sulfate particles in the negative electrode electrode material is 0.1% by mass or more, 0.5% by mass or more, or 1% by mass. It may be% or more.

(11) In any one of the above (1) to (10), even if the content of the barium sulfate particles in the negative electrode electrode material is 7.5% by mass or less or 5.3% by mass or less. good.

(12) In any one of the above (1) to (11), the average particle diameter of the barium sulfate particles in the negative electrode material is 1 μm or less, 0.7 μm or less, 0.6 μm or less, 0.4 μm or less. , Or may be 0.3 μm or less.

(13) In any one of the above (1) to (12), the average particle size of the barium sulfate particles in the negative electrode material may be 0.01 μm or more.

(14) In any one of the above (1) to (13), the maximum particle size of the barium sulfate particles may be 2.5 μm or less, or 2 μm or less.

(15) In any one of the above (1) to (14), the negative electrode material may contain a carbonaceous material.

(16) In the above (15), the content of the carbonaceous material in the negative electrode material may be 0.1% by mass or more.

(17) In the above (15) or (16), the content of the carbonaceous material in the negative electrode material may be 3.5% by mass or less.

(18) In any one of the above (1) to (17), the negative electrode electrode material may contain an organic shrinkage proofing agent.

(19) In the above (18), the content of the organic shrinkage barrier in the negative electrode electrode material may be 0.01% by mass or more.

(20) In the above (18) or (19), the content of the organic shrinkage barrier in the negative electrode electrode material may be 1.2% by mass or less.

(21) In any one of the above (1) to (20), the negative electrode material may include a reinforcing material.

(22) In the above (21), the content of the reinforcing material in the negative electrode electrode material may be 0.03% by mass or more.

(23) In the above (21) or (22), the content of the reinforcing material in the negative electrode electrode material may be 0.6% by mass or less.

(24) In any one of the above (1) to (23), the specific gravity of the electrolytic solution at 20 ° C. may be 1.10 or more.

(25) In any one of the above (1) to (24), the specific gravity of the electrolytic solution at 20 ° C. may be 1.35 or less.

(26) In any one of the above (1) to (25), the electrode plate group of the lead storage battery includes at least one positive electrode plate, at least one negative electrode plate, and a separator interposed between the positive electrode plate and the negative electrode plate. May be provided.

(27) In the above (26), when the electrode plate group includes two or more negative electrode plates, at least one negative electrode plate is a negative electrode plate that satisfies at least one of the above conditions (a) and (b). There may be a negative electrode plate in which 50% or more or 80% or more of the number of negative electrode plates included in the electrode plate group satisfies at least one of the above conditions (a) and (b). All of the negative electrode plates included in the electrode plate group may be negative electrode plates satisfying at least one of the above conditions (a) and (b).

(28) In the above (27), the ratio of the number of negative electrode plates that satisfy at least one of the above conditions (a) and (b) among the negative electrode plates included in the electrode plate group is usually 100%. It is as follows.

(29) A method for manufacturing a negative electrode plate for a lead storage battery.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size (D50) of the barium sulfate powder is 1 μm or less.
A method for manufacturing a negative electrode plate for a lead storage battery, wherein the liquid is an aqueous solution of sulfuric acid.

(30) In the above (29), the density of the aqueous sulfuric acid solution at 20 ° C. may be, for example, larger than 1 g / cm ³ and 1.03 g / cm ³ or more.

(31) In the above (29) or (30), the density of the aqueous sulfuric acid solution at 20 ° C. may be 1.4 g / cm ³ or less.

(32) In any one of the above (29) to (31), the average particle size (D50) of the barium sulfate powder is 0.7 μm or less, 0.6 μm or less, 0.4 μm or less, or 0.3 μm. It may be as follows.

(33) A method for manufacturing a negative electrode plate for a lead storage battery.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size of the barium sulfate powder is 0.4 μm or less, and the average particle size is 0.4 μm or less.
A method for manufacturing a negative electrode plate for a lead storage battery, wherein the liquid is pure water.

(34) In the above (33), the electrical resistivity of the pure water may be 0.1 MΩ · cm or more.

(35) In the above (33) or (34), the electrical resistivity of the pure water may be 1.5 MΩ · cm or less.

(36) In any one of the above (33) to (35), the average particle size (D50) of the barium sulfate powder may be 0.3 μm or less.

(37) In any one of the above (29) to (36), the average particle size of the barium sulfate powder may be 0.01 μm or more.

(38) In any one of the above (29) to (37), the maximum particle size of the barium sulfate powder may be 2.5 μm or less, or 2 μm or less.

(39) In any one of the above (29) to (38), the content of barium sulfate in the dispersion is 55% by mass or less, 40% by mass or less, 30% by mass or less, or 25% by mass or less. May be.

(40) In any one of the above (29) to (39), the content of barium sulfate in the dispersion is 0.1% by mass or more, 1% by mass or more, or 5% by mass or more. May be good.

(41) In any one of the above (29) to (40), the barium sulfate powder and the liquid may be mixed at 10 ° C. or higher, or 20 ° C. or higher.

(42) In any one of the above (29) to (41), the barium sulfate powder and the liquid may be mixed at 60 ° C. or lower or 40 ° C. or lower.

(43) In any one of the above (29) to (42), the amount of the barium sulfate powder is 0.1 part by mass or more, 0.5 by mass with respect to 100 parts by mass of the powder containing the lead oxide as a main component. It may be 1 part by mass or more, or 1 part by mass or more.

(44) In any one of the above (29) to (43), the amount of the barium sulfate powder is 7 parts by mass or less or 5 parts by mass or less with respect to 100 parts by mass of the powder containing the lead oxide as a main component. May be.

(45) In any one of the above (29) to (44), the proportion of the lead oxide in the powder containing the lead oxide as a main component is, for example, more than 50% by mass and 70% by mass or more. May be.

(46) In any one of the above (29) to (45), the ratio of the other component (lead powder, etc.) to the powder containing the lead oxide as a main component is 30% by mass or less. May be good.

(47) In any one of the above (29) to (46), the carbonaceous material may be further mixed in the second step.

(48) In the above (47), the amount of the carbonaceous material may be 0.1 part by mass or more with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

(49) In the above (47) or (48), the amount of the carbonaceous material may be 3.5 parts by mass or less with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

(50) In any one of the above (29) to (49), an organic shrink-proofing agent may be further mixed in the second step.

(51) In the above (50), the amount of the organic shrink-proofing agent may be 0.01 part by mass or more with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

(52) In the above (50) or (51), the amount of the organic shrink-proofing agent may be 1.2 parts by mass or less with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

(53) In any one of the above (29) to (52), a reinforcing material may be further mixed in the second step.

(54) In the above (53), the amount of the reinforcing material may be 0.03 part by mass or more with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

(55) In the above (53) or (54), the amount of the reinforcing material may be 0.6 parts by mass or less with respect to 100 parts by mass of the powder containing the lead oxide as a main component.

FIG. 1 shows the appearance of an example of a lead storage battery.
The lead-acid battery 1 includes an electric tank 12 for accommodating a plate group 11 and an electrolytic solution (not shown). The inside of the electric tank 12 is partitioned into a plurality of cell chambers 14 by a partition wall 13. In each cell chamber 14, one electrode plate group 11 is housed. The opening of the battery case 12 is closed by a lid 15 including a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a liquid spout 18 for each cell chamber. At the time of refilling water, the liquid spout 18 is removed and the refilling liquid is replenished. The liquid spout 18 may have a function of discharging the gas generated in the cell chamber 14 to the outside of the battery.

The electrode plate group 11 is configured by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via a separator 4, respectively. Here, the bag-shaped separator 4 accommodating the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. In the cell chamber 14 located at one end of the battery case 12, the negative electrode shelf portion 6 for connecting the plurality of negative electrode plates 2 in parallel is connected to the through connection body 8, and the positive electrode shelf portion for connecting the plurality of positive electrode plates 3 in parallel is connected. 5 is connected to the positive electrode column 7. The positive electrode column 7 is connected to the positive electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative electrode column 9 is connected to the negative electrode shelf portion 6, and the penetration connecting body 8 is connected to the positive electrode shelf portion 5. The negative electrode column 9 is connected to the negative electrode terminal 16 outside the lid 15. Each through-connecting body 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plates 11 of the adjacent cell chambers 14 in series.

FIG. 4 is a process diagram for explaining a method for manufacturing a negative electrode plate for a lead storage battery according to an embodiment of the present disclosure. In the example of FIG. 4, first, a barium sulfate powder and a liquid are mixed to prepare a dispersion (S1). Next, the dispersion liquid and the powder containing lead oxide as a main component are mixed to prepare a negative electrode paste (S2). A dispersion medium is usually used to prepare the negative electrode paste. Then, a negative electrode plate is manufactured using the negative electrode paste (S3).

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

<< Batteries E1 to E26 and R1 to R2 >>
(1) Preparation of negative electrode plate Barium sulfate powder having the average particle size shown in the table and the liquid shown in the table are placed in a container and dispersed by mixing with a stirrer and a stirrer at 25 ° C. and an atmospheric atmosphere. The liquid was prepared. The content of barium sulfate particles in the dispersion was 9 to 23% by mass. Among the liquids, as the lignin aqueous solution, an aqueous solution (lignin concentration: 0.05% by mass) in which lignin (sodium lignin sulfonate) was dissolved in pure water was used.

Mixture A was obtained by mixing a powder containing lead oxide as a main component, carbon black, a reinforcing material (synthetic resin fiber), and lignin (sodium lignin sulfonate) as needed. Pure water, a dispersion using an aqueous lignin solution, or a dispersion using pure water was added to the mixture A and mixed to obtain a mixture B. When pure water was added to the mixture A, a dispersion liquid using an aqueous sulfuric acid solution was added to the mixture B and mixed. When the dispersion was added to the mixture A, an aqueous sulfuric acid solution was added to the mixture B and the mixture was mixed. In this way, the negative electrode paste was prepared. When a dispersion liquid using an aqueous lignin solution was used as the mixture B, lignin was not used in the preparation of the mixture A.

The negative electrode paste was filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy, aged and dried to obtain an unchemical negative electrode plate (width 100 mm, height 115 mm, thickness 1.2 mm). The amounts of carbon black, lignin and synthetic resin fibers were adjusted to be 0.3% by mass, 0.1% by mass and 0.1% by mass, respectively, when measured in a fully charged state. The amount of the dispersion liquid added was adjusted so that the amount of barium sulfate (parts by mass) with respect to 100 parts by mass of the powder containing lead oxide as a main component became the value shown in the table.

(2) Preparation of positive electrode plate A positive electrode paste was prepared by mixing powder containing lead oxide as a main component, a reinforcing material (synthetic resin fiber), water and sulfuric acid. The positive electrode paste was filled in the mesh portion of the expanded lattice made of Pb—Ca—Sn alloy, aged and dried to obtain an unchemical positive electrode plate (width 100 mm, height 115 mm, thickness 1.6 mm). ..

(3) Preparation of Lead-acid Battery The unchemical negative electrode plate was housed in a bag-shaped separator and laminated with the positive electrode plate to form a group of electrode plates with 7 unchemical negative electrode plates and 6 unchemical positive electrode plates. ..

The ears of the positive electrode plate and the ears of the negative electrode plate were welded to the positive electrode shelf and the negative electrode shelf, respectively. The electrode plate group is inserted into a polypropylene battery case, an electrolytic solution is injected, and chemical conversion is performed in the battery tank. The rated voltage is 12 V and the rated capacity is 30 Ah (5-hour rate capacity (Ah described in the rated capacity). The liquid lead-acid batteries E1 to E26 and R1 to R2 of the liquid type lead storage battery E1 to E26 and R1 to R2 of the liquid type lead storage battery (capacity when discharging with the current (A) of 1/5 of the value of (A)) were assembled. In the battery case, six electrode plates are connected in series.

A sulfuric acid aqueous solution was used as the electrolytic solution. The specific gravity of the electrolytic solution after chemical conversion at 20 ° C. was 1.285.

<< Lead-acid batteries C1 to C8 >>
Barium sulfate powder having the average particle size shown in the table, powder containing lead oxide as a main component, carbon black, lignin (sodium lignin sulfonate), and a reinforcing material (synthetic resin fiber) were mixed. Pure water was added to the mixture and mixed. An aqueous sulfuric acid solution was added to the obtained mixture and mixed to prepare a negative electrode paste. A negative electrode plate was produced and a lead storage battery was produced in the same manner as the lead storage batteries E1 to E26 except that the obtained negative electrode paste was used.

"evaluation"
(1) Regenerative acceptance The lead storage battery produced above was fully charged according to the procedure described above, and the regenerative acceptance was evaluated at 25 ° C ± 2 ° C by the following procedure.
The lead-acid battery was discharged for 0.5 hours at the 5-hour rate current defined in JIS D5301: 2019 to adjust the SOC to 90%. Then, the lead storage battery was left (paused) for 12 hours. The lead-acid battery was charged at a constant voltage of 2.42 V / cell with a maximum current of 100 A. At this time, the amount of electricity charged in 10 seconds from the start of charging is obtained. Regenerative acceptability is evaluated based on this amount of electricity. The regenerative acceptability of each lead storage battery is shown as a relative value (%) when the value obtained by the lead storage battery C1 is taken as 100%.

(2) Measurement of XRD spectrum of negative electrode material In the procedure described above, the XRD spectrum of the negative electrode material collected from the negative electrode plate at 50% SOC was measured, and 2θ = 29 corresponding to the [211] plane of lead sulfate. The half-value full width of the peak near 6.6 ° was obtained.

(3) EPMA analysis According to the procedure described above, the EPMA analysis of the cross section of the negative electrode plate is performed, the intensity of R of RGB attributed to the characteristic X-ray of Ba is adjusted to the maximum value, and the intensity is halved of the maximum value. Was used as the threshold value, and the ratio of the portion showing the intensity equal to or higher than the threshold value to the region A when the binarization process was performed was determined. In addition, the number of islands having an area ratio of 0.05% or more of the region A among the portions showing strength equal to or higher than the threshold value was determined.

(4) Imaging with a scanning electron microscope For each of the lead storage batteries E15 and C5, a negative electrode plate before separating the negative electrode material in the process of preparing sample A by the procedure described above was obtained with a scanning electron microscope (SEM:). Photographed by Scanning Electron Microscope).

Tables 1 and 2 show the evaluation results of regenerative acceptance. The table also shows the specific gravity of the liquid used to prepare the dispersion.

As shown in Table 1, when barium sulfate powder is mixed with a powder containing lead oxide as a main component without preparing a dispersion in advance, if the average particle size of the barium sulfate powder becomes smaller, the regenerative acceptability Tends to decrease (C1 to C6). On the other hand, if a dispersion liquid in which barium sulfate powder is dispersed using pure water or an aqueous solution of sulfuric acid is prepared in advance, high regenerative acceptability can be obtained even if the average particle size of the barium sulfate powder is small (E1 to E18). ).

As shown in Table 2, when barium sulfate powder is mixed with a powder containing lead oxide as a main component without adjusting the dispersion in advance, the larger the amount of barium sulfate powder, the lower the regenerative acceptability. There is a tendency (C7, C5, and C8). On the other hand, if a dispersion liquid in which barium sulfate powder is dispersed using pure water or an aqueous solution of sulfuric acid is prepared in advance, the larger the amount of barium sulfate powder, the better the regenerative acceptability (C7, C5 and C8, and E12). Comparison with ~ E15 and E19 ~ E26). Further, the higher the density of the liquid used for preparing the dispersion liquid, the higher the regenerative acceptability can be obtained.

For lead-acid batteries C1, E2, C5, E12 to E15, and E26, the full width at half maximum of the peak corresponding to the [211] plane of lead sulfate in the XRD spectrum, and the ratio of the portion showing the intensity above the threshold in EPMA analysis to the region A. Table 3 shows the number of islands having an area ratio of 0.05% or more of the region A.

As shown in Table 3, when the negative electrode plate satisfies the condition (a) or the condition (b), high regenerative acceptability was obtained. From the viewpoint of ensuring higher regenerative acceptability, the ratio of the portion exhibiting the intensity above the threshold value to the region A is preferably 2.8 or less, more preferably 2.5 or less, and more preferably 1.0 or less. More preferred. Although Table 3 shows the results for some lead-acid batteries, the same or similar results as those shown in Table 3 can be obtained for other lead-acid batteries E1 to E11 and E16 to E25.

The SEM images of the negative electrode plates at 50% SOC of the lead-acid batteries E15 and C5 are shown in FIGS. 2 and 3, respectively. As shown in FIGS. 2 and 3, in the lead storage battery E15, the particle size of lead sulfate produced during discharge is smaller than that in the lead storage battery C5, and it can be seen that coarsening is suppressed.

Although the present invention has been described with respect to preferred embodiments at this time, such disclosure should not be construed in a limited way. Various modifications and modifications will undoubtedly become apparent to those skilled in the art belonging to the present invention by reading the above disclosure. Accordingly, the appended claims should be construed to include all modifications and modifications without departing from the true spirit and scope of the invention.

The lead-acid battery according to the first aspect and the second aspect of the present invention is suitable for applications requiring high regenerative acceptability. Similarly, the manufacturing method according to the third aspect and the fourth aspect of the present invention is suitable for manufacturing a negative electrode plate of a lead storage battery, which requires high regenerative acceptance. The lead-acid battery including the above-mentioned lead-acid battery and the negative electrode plate obtained by the above-mentioned manufacturing method can be used as a power source for starting a vehicle (automobile, motorcycle, etc.), an industrial power storage device (for example, a power source for an electric vehicle (forklift, etc.)), etc. Suitable for. However, the applications of lead-acid batteries and negative electrode plates are not limited to these.

1: Lead-acid battery 2: Negative electrode plate 3: Positive electrode plate 4: Separator 5: Positive electrode shelf part 6: Negative electrode shelf part 7: Positive electrode pillar 8: Through connection body 9: Negative electrode pillar 11: Electrode plate group 12: Electric tank 13: Bulk partition 14: Cell chamber 15: Lid 16: Negative electrode terminal 17: Positive electrode terminal 18: Liquid spout

Claims

It ’s a lead-acid battery.
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The half-value full width of the peak corresponding to the [211] plane of lead sulfate in the X-ray diffraction spectrum of the negative electrode material when the lead-acid battery is fully charged and then discharged to a 50% charged state with a 5-hour rate current is Lead-acid battery with a temperature of 0.137 ° or higher.
The lead-acid battery according to claim 1, wherein the full width at half maximum is 0.139 ° or more.
The lead-acid battery according to claim 1 or 2, wherein the full width at half maximum is 0.2 ° or less.
The number of pixels of the image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron probe microanalyzer on the cross section parallel to the thickness direction of the negative electrode plate is assigned to the characteristic X-ray of Ba in the region of 200 × 400 in the X direction. When the intensity of R of RGB is adjusted to the maximum value and the binarization process is performed with the intensity of 1/2 of the maximum value as the threshold value, the ratio of the portion showing the intensity equal to or higher than the threshold value to the region is 2.8. The lead storage battery according to any one of claims 1 to 3, which is% or less.
The lead-acid battery according to claim 4, wherein the number of islands having an area ratio of 0.05% or more in the area is 1 or less in the portion.
It ’s a lead-acid battery.
The lead-acid battery comprises at least one cell comprising a group of plates and an electrolyte.
The electrode plate group includes a positive electrode plate, a negative electrode plate, and a separator interposed between the negative electrode plate and the positive electrode plate.
The negative electrode plate comprises a negative electrode material containing barium sulfate particles.
The number of pixels of the image having a resolution of 250 dpi or more and 350 dpi or less analyzed by an electron probe microanalyzer on the cross section parallel to the thickness direction of the negative electrode plate is assigned to the characteristic X-ray of Ba in the region of 200 × 400 in the X direction. Of the portion showing the intensity equal to or higher than the threshold value when the intensity of R of RGB is adjusted to the maximum value and the binarization process is performed with the intensity of 1/2 of the maximum value as the threshold value, 0.05% of the area. A lead storage battery in which the number of islands having the above area ratio is one or less.
The lead-acid battery according to claim 6, wherein the ratio of the portion to the region is 2.8% or less.
The lead-acid battery according to any one of claims 1 to 7, wherein the content of the barium sulfate particles in the negative electrode electrode material is 0.5% by mass or more.
The lead-acid battery according to any one of claims 1 to 8, wherein the content of the barium sulfate particles in the negative electrode electrode material is 7.5% by mass or less.
The lead-acid battery according to any one of claims 1 to 9, wherein the barium sulfate particles have an average particle size of 1 μm or less in the negative electrode material.
The lead-acid battery according to any one of claims 1 to 10, wherein the barium sulfate particles have an average particle size of 0.01 μm or more in the negative electrode material.
A method for manufacturing negative electrode plates for lead-acid batteries.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size of the barium sulfate powder is 1 μm or less, and the average particle size is 1 μm or less.
A method for manufacturing a negative electrode plate for a lead storage battery, wherein the liquid is an aqueous solution of sulfuric acid.
The method for manufacturing a negative electrode plate for a lead storage battery according to claim 12, wherein the density of the aqueous sulfuric acid solution at 20 ° C. is 1.03 g / cm 3 or more.
A method for manufacturing negative electrode plates for lead-acid batteries.
The manufacturing method is
The first step of mixing barium sulfate powder and liquid to prepare a dispersion,
A second step of mixing the dispersion liquid and a powder containing a lead oxide as a main component to prepare a negative electrode paste is provided.
The average particle size of the barium sulfate powder is 0.4 μm or less, and the average particle size is 0.4 μm or less.
A method for manufacturing a negative electrode plate for a lead storage battery, wherein the liquid is pure water.
The method for manufacturing a negative electrode plate for a lead storage battery according to any one of claims 12 to 14, wherein the barium sulfate powder has an average particle size of 0.01 μm or more.
The negative electrode plate for a lead storage battery according to any one of claims 12 to 15, wherein the amount of the barium sulfate powder is 0.5 parts by mass or more with respect to 100 parts by mass of the powder containing the lead oxide as a main component. Production method.
The method for manufacturing a negative electrode plate for a lead storage battery according to any one of claims 12 to 16, wherein the amount of the barium sulfate powder is 7 parts by mass or less with respect to 100 parts by mass of the powder containing lead oxide as a main component. ..
The method for manufacturing a negative electrode plate for a lead storage battery according to any one of claims 12 to 17, wherein the content of barium sulfate in the dispersion is 55% by mass or less.