JP6750376B2 - Lead acid battery - Google Patents

Description

The present invention relates to a lead storage battery.

Lead acid batteries are used in various applications such as in-vehicle and industrial applications. The lead storage battery includes a negative electrode plate, a positive electrode plate, and an electrolytic solution. A separator is arranged between the negative electrode plate and the positive electrode plate. The positive electrode plate includes a positive electrode current collector and a positive electrode electrode material, and the negative electrode plate includes a negative electrode current collector and a negative electrode electrode material.

The negative electrode material contains an active material (lead or lead sulfate) that exhibits a capacity by a redox reaction, and various additives. For example, the discharge performance of the lead storage battery can be improved by adding an organic shrinkage preventive agent to the negative electrode material. As organic shrinkage inhibitors, it has been proposed to use synthetic organic shrinkage inhibitors in addition to lignin or lignosulfonic acid derived from natural products.

In Patent Document 1, a negative electrode material contains a bisphenol condensate as a synthetic organic shrink-proofing agent.

Patent Document 2 uses a negative electrode active material containing lignin. In Patent Document 2, a separator having a base and ribs and having a thickness of 0.7 mm or more and 1.7 mm or less is used.

On the other hand, Patent Document 3 discloses a lead/sulfuric acid battery having a total thickness of about 1 to about 3.75 mm, preferably about 1.5 to 2.5 mm, and a microporous plastic or glass-fiber or A separator composed of both of them is arranged.

International Publication No. 2015-181865 Pamphlet JP, 2015-88379, A JP-A-5-89868

Addition of the organic anti-shrink agent to the negative electrode material reduces the specific resistance of the negative electrode material and improves the high rate discharge performance of the lead storage battery at low temperatures. Above all, when a synthetic organic shrinkproofing agent is used, the specific resistance is remarkably reduced. However, on the other hand, the heavy load life performance of the lead storage battery may be reduced.

One embodiment of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolytic solution, the negative electrode plate includes a negative electrode current collector, and a negative electrode material, and the negative electrode material is synthetic organic shrink-proof. And a distance between the negative electrode plate and the positive electrode plate of 0.9 mm or more and 2 mm or less.

Another aspect of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolytic solution, the negative electrode plate includes a negative electrode current collector and a negative electrode material, and the negative electrode material is an organic shrink-proof material. The present invention relates to a lead storage battery, which contains an agent, has a distance between the negative electrode plate and the positive electrode plate of 0.9 mm or more and 2 mm or less, and contains the element sulfur of 3000 μmol/g or more.

According to the present invention, it is possible to provide a lead storage battery having excellent heavy load life performance.

FIG. 1 is an exploded perspective view with a part cut away showing an external appearance and an internal structure of a lead storage battery according to an embodiment of the present invention. It is a figure which shows the relationship between electrode gap and the amount of fall of positive electrode material. It is a figure which shows the relationship between the content of the organic anti-shrink agent in a negative electrode material, and the amount of omission of a positive electrode material. It is a figure which shows the relationship between the distance between poles and the number of heavy load life cycles when changing the content of the sulfur element in an organic anti-shrink agent. It is a figure which shows the relationship between the sulfur (S) element content in an organic shrinkage agent, and low temperature high rate (low temperature HR) discharge performance. It is a figure which shows the relationship between the sulfur (S) element content in an organic shrinkage agent, and the elution amount of an organic shrinkage agent. It is a figure which shows the relationship between the density of a negative electrode material, and heavy load life performance when changing the sulfur element content in an organic shrink-proofing agent.

A lead-acid battery according to an aspect of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolytic solution, the negative electrode plate includes a negative electrode current collector, and a negative electrode material, and the negative electrode material is synthetic organic shrink-proof. The distance between the negative electrode plate and the positive electrode plate including the agent is 0.9 mm or more and 2 mm or less, and preferably 1 mm or more and 1.8 mm or less.

Further, a lead storage battery according to another aspect of the present invention includes a negative electrode plate, a positive electrode plate, and an electrolytic solution, the negative electrode plate includes a negative electrode current collector and a negative electrode material, the negative electrode material, The organic anti-shrink agent contains an organic anti-shrink agent, and the distance between the negative electrode plate and the positive electrode plate is 0.9 mm or more and 2 mm or less, preferably 1 mm or more and 1.8 mm or less. g or more, and preferably 4000 μmol/g or more.

The lead acid battery may be a liquid type (vent type) lead acid battery or a control valve type (sealed type) lead acid battery, but a liquid type lead acid battery is suitable as an embodiment of the present invention.

If the organic shrink-proofing agent is contained in the negative electrode material, the heavy load life performance may decrease. It is considered that the reason why the heavy load life performance is deteriorated is that the organic shrinkage preventer eluted from the negative electrode plate into the electrolytic solution softens the positive electrode material.

On the other hand, when the distance between the negative electrode plate and the positive electrode plate (hereinafter, also referred to as inter-electrode distance) is set to 0.9 mm or more, preferably 1 mm or more, excellent heavy load life performance is obtained. .. It is considered that by setting the distance between the electrodes to be 0.9 mm or more, it becomes difficult for the organic anti-shrink agent dissolved in the electrolytic solution to act on the positive electrode material. As a result, it is considered that the amount of the positive electrode material dropped off and the deterioration of the positive electrode plate being suppressed are largely related to the improvement of the heavy load life performance.

When using lignin derived from a natural product, there is no tendency to suppress softening of the positive electrode material even if the distance between the electrodes is 0.9 mm or more. Deterioration of the positive electrode plate is suppressed by setting the distance between the electrodes to 0.9 mm or more because it is a unique phenomenon when a synthetic organic shrinkage inhibitor or an organic shrinkage inhibitor with a sulfur element content of 3000 μmol/g or more is used. It is believed that there is.

The elution of the synthetic organic shrink-proofing agent becomes remarkable when the content of the elemental sulfur in the synthetic organic shrink-proofing agent is 3000 μmol/g or less, and becomes more remarkable when it is 2500 μmol/g or less. In this case, the distance between the poles has a large influence on the heavy load life performance, so it is more important to set the distance between the poles to 0.9 mm or more.

On the other hand, when the content of elemental sulfur in the organic anti-shrink agent is 3000 μmol/g or more or exceeds 3000 μmol/g, the organic anti-shrink agent is difficult to elute from the negative electrode plate into the electrolytic solution, and the heavy load life performance of the organic anti-shrink agent is improved. The effect of making it extremely large. Moreover, the effect of improving the low temperature high rate discharge performance is also large. Therefore, by setting the inter-electrode distance to be 0.9 mm or more, the low temperature high rate discharge performance and the heavy load life performance can be compatible at a more excellent level. Above all, when the content of the elemental sulfur in the organic anti-shrink agent is 4000 μmol/g or more, the elution amount of the organic anti-shrink agent becomes very small and the heavy load discharge performance should be stabilized at a very high level. You can

From the viewpoint of obtaining good heavy load life performance, the larger the inter-electrode distance, the better. Specifically, the distance between the electrodes is preferably more than 1 mm, more preferably 1.2 mm or more, further preferably 1.4 mm or more. It should be noted that when an organic shrinkage inhibitor is added to the negative electrode material, the specific resistance of the negative electrode material decreases and the high rate discharge performance at low temperature of the lead storage battery improves, but if the inter-electrode distance is too large, low temperature high rate discharge will occur. Performance improvement is suppressed. Therefore, the distance between the electrodes is preferably 2.0 mm or less, and preferably 1.8 mm or less.

The synthetic organic anti-shrink agent can increase the content of elemental sulfur as compared with conventional lignin or lignosulfonic acid derived from a natural product (hereinafter referred to as lignin). Therefore, when a synthetic organic shrink proofing agent is used instead of lignin, it is possible to greatly improve the low temperature high rate discharge performance and the heavy load discharge performance of the lead storage battery.

From the viewpoint of enhancing the effect of improving low-temperature high-rate discharge performance and heavy load life performance, the content of the elemental sulfur in the organic anti-shrink agent is preferably 3000 μmol/g or more, more preferably 4000 μmol/g or more, and 5000 μmol/g The above is more preferable. On the other hand, there is a limit in increasing the content of elemental sulfur in the organic shrink-proofing agent. Therefore, the content of elemental sulfur in the organic anti-shrink agent is preferably 10,000 μmol/g or less, more preferably 9000 μmol/g or less, and further preferably 8000 μmol/g or less. The content of elemental sulfur contained in the lignin is usually 500 to 600 μmol/g.

Here, the content of the elemental sulfur in the organic anti-shrink agent is X μmol/g means that the content of the elemental sulfur contained in 1 g of the organic anti-shrink agent is X μmol.

The organic anti-shrink agent is an organic polymer containing elemental sulfur, and generally contains one or more, preferably a plurality of aromatic rings in the molecule, and contains elemental sulfur as a sulfur-containing group. Among the sulfur-containing groups, sulfonic acid groups or sulfonyl groups, which are stable forms, are preferable. The sulfonic acid group may be present in an acid form or in a salt form such as Na salt.

As a specific example of the organic anti-shrink agent, a condensate of formaldehyde with a compound having a sulfur-containing group and having one or more, preferably two or more aromatic rings is preferable. As the compound having two or more aromatic rings, it is preferable to use bisphenols, biphenyls, naphthalenes and the like. Bisphenols, biphenyls, and naphthalenes are generic terms for compounds having a bisphenol skeleton, a biphenyl skeleton, and a naphthalene skeleton, and each may have a substituent. These may be contained alone or in plural kinds in the organic anti-shrink agent. As the bisphenol, bisphenol A, bisphenol S, bisphenol F and the like are preferable. Among them, bisphenol S is a sulfonyl group in the bisphenol skeleton (-SO ₂ -) because they have, it is easy to increase the content of the sulfur element.

The sulfur-containing group may be directly bonded to an aromatic ring such as bisphenols, biphenyls and naphthalene, and may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group. Alternatively, a monocyclic aromatic compound such as aminobenzenesulfonic acid or alkylaminobenzenesulfonic acid may be condensed with formaldehyde together with a compound having two or more aromatic rings. The bisphenol condensate is suitable for a lead storage battery that is exposed to a temperature environment higher than room temperature because the performance at a low temperature is not impaired even if it experiences a temperature environment higher than room temperature. Compared to condensates of bisphenols, the condensate of naphthalene sulfonic acid is less likely to have a smaller polarization, so it is suitable for lead acid batteries where liquid reduction characteristics are important.

Organic compounds such as N,N'-(sulfonyldi-4,1-phenylene)bis(1,2,3,4-tetrahydro-6-methyl-2,4-dioxopyrimidine-5-sulfonamide) condensate You may use as a shrinkproofing agent.

The content of the organic anti-shrink agent contained in the negative electrode material does not greatly affect the action of the organic anti-shrink agent within the general range. The content of the organic anti-shrink agent contained in the negative electrode material is, for example, preferably 0.01% by mass or more, more preferably 0.02% by mass or more, further preferably 0.05% by mass or more, while 1.0 The content is preferably not more than mass%, more preferably not more than 0.8 mass%, further preferably not more than 0.3 mass%. Here, the content of the organic anti-shrink agent contained in the negative electrode material is the content in the negative electrode material obtained by the method described later from the already-formed fully charged lead storage battery.

The density of the negative electrode material, from the viewpoint of weight reduction of the lead-acid battery, for example, preferably 2.5~4.0g / cm ^3, more preferably 2.5~3.8g / cm ^3, 2.5~3 0.5 g/cm ³ is more preferable, and 2.5 to 3.0 g/cm ³ is particularly preferable. However, when the negative electrode material has a low density as described above and the content of the sulfur element in the organic shrink proofing agent is 3000 μmol/g or less, the heavy load life performance is likely to deteriorate. From the viewpoint of suppressing deterioration of heavy load life performance, when the density of the negative electrode material is 2.5 to 4.0 g/cm ³ , the content of the sulfur element in the organic shrink proofing agent exceeds 3000 μmol/g. It is preferably 4000 μmol/g or more, more preferably 5000 μmol/g or more.

Next, a method of analyzing each physical property will be described.
(1) Density of Negative Electrode Material The density of the negative electrode material means the value of the bulk density of the negative electrode material after chemical conversion, and is measured as follows. The battery after chemical formation is fully charged and then disassembled, and the obtained negative electrode plate is washed with water and dried to remove the electrolytic solution in the negative electrode plate. Then, the negative electrode material is separated from the negative plate to obtain an uncrushed measurement sample. After charging the sample into the measuring container and evacuating it, filling the mercury with a pressure of 0.5 to 0.55 psia, measuring the bulk volume of the negative electrode material, and dividing the mass of the measurement sample by the bulk volume. The bulk density of the negative electrode material is determined. The volume obtained by subtracting the volume of mercury injected from the volume of the measurement container is the bulk volume.

The auxiliary charging conditions for fully charging the lead storage battery are as follows.
In the case of a liquid lead-acid battery, constant current charging is performed at 25° C. in a water tank at a rate current of 5 hours until reaching 2.5 V/cell, and then at a rate current of 5 hours for 2 hours. Further, in the case of a control valve type lead-acid battery, constant-current constant-voltage charging of 2.23 V/cell is performed at 25° C. in a gas tank in a 5-hour rate current, and the charging current during constant-voltage charging becomes 1 mCA or less. Charging is terminated when
The 5-hour rate current in this specification is a current value at which the battery nominal capacity is discharged in 5 hours. For example, in the case of a battery having a nominal capacity of 30 Ah, the 5-hour rate current is 6 A and 1 mCA is 30 mA.

(2) Analysis of Organic Shrinkproof Agent First, a lead storage battery which has been fully charged after formation is decomposed, a negative electrode plate is taken out, sulfuric acid is removed by washing with water, and dried. Next, a negative electrode material (initial sample) is collected from the dried negative electrode plate, and the initial sample is analyzed by the following method.

(2-1) Qualitative determination of organic shrinkage inhibitor in negative electrode material An initial sample is immersed in a 1 mol/L NaOH aqueous solution to extract the organic shrinkage inhibitor. Next, insoluble components are removed by filtration from the extracted NaOH aqueous solution containing an organic shrinkage inhibitor, and the obtained filtrate is desalted, then concentrated and dried. Desalting may be performed by putting the filtrate in a dialysis tube and immersing it in distilled water. This gives a powder sample of the organic shrink proofing agent.

Infrared spectrum measured using a powder sample, UV-visible absorption spectrum measured with an ultraviolet-visible photometer by dissolving the powder sample with distilled water, etc., a solution obtained by dissolving the powder sample with a predetermined solvent such as heavy water It is possible to specify the organic anti-shrink agent by combining the information obtained from the NMR spectrum of the above.

(2-2) Quantification of Content of Organic Strain Retardant in Negative Electrode Material In the same manner as in (2-1) above, after obtaining a filtrate of an aqueous NaOH solution containing an organic strain suppressor, an ultraviolet-visible absorption spectrum of the filtrate was measured. To do. The content of the organic anti-shrinking agent in the negative electrode material can be quantified using the spectral intensity and the calibration curve prepared in advance.
When obtaining the battery and measuring the content of the organic strain suppressor, if the same organic strain suppressor cannot be used in the calibration curve because the structural formula of the organic strain suppressor cannot be rigorously specified, the negative electrode of the battery By preparing a calibration curve using an organic shrinkage agent extracted from the above-mentioned organic shrinkage agent, which has a similar shape to the UV-visible absorption spectrum, infrared spectrum, and NMR spectrum, etc. The content of the organic shrink proofing agent is measured using the absorption spectrum.

(2-3) Content of elemental sulfur in organic strain suppressor As in (2-1) above, after obtaining a powder sample of the organic strain suppressor, the content of 0.1 g of the organic strain suppressor was measured by the oxygen combustion flask method. The elemental sulfur is converted to sulfuric acid. At this time, by burning the powder sample in the flask containing the adsorbent, an eluate in which sulfate ions are dissolved in the adsorbent is obtained. Next, the eluate is titrated with barium perchlorate using thorin as an indicator to determine the content (C1) of the elemental sulfur in 0.1 g of the organic shrink proofing agent. Next, C1 is multiplied by 10 to calculate the content (μmol/g) of the elemental sulfur in the organic shrink-proofing agent per 1 g.

(3) Measurement (calculation) of distance between poles
As the inter-electrode distance, a CT image or an X-ray photograph of a lead storage battery that has been fully charged after formation is taken, and the distance between the negative electrode plate and the positive electrode plate at the center of the height direction of the negative electrode plate and the positive electrode plate adjacent to each other Just ask. Generally, a lead-acid battery includes a plurality of negative electrode plates and a plurality of positive electrode plates, respectively. Therefore, it is preferable that the above-mentioned distances between a plurality of pairs (preferably three or more pairs) of the negative electrode plate and the positive electrode plate adjacent to each other be obtained, and the average value thereof be set as the inter-electrode distance.

The distance between the poles may be calculated. Lead-acid batteries generally include an electrode plate group in which a plurality of negative electrode plates and a plurality of positive electrode plates are alternately stacked with a separator interposed therebetween. Here, the plurality of negative electrode plates are connected to each other in parallel by the shelf-shaped connecting members, and the plurality of positive electrode plates are similarly connected to each other in parallel to each other by the shelf-shaped connecting members. Therefore, the arrangement of the negative electrode plate and the positive electrode plate in the lead storage battery is regulated by the shelf-shaped connecting member, and the thickness of the electrode plate group is also determined. In addition, the thickness of the electrode plate group may be restricted by the space in which the electrode plate group is housed. In any case, if the number and thickness of each of the negative electrode plate and the positive electrode plate are determined, the distance between the electrodes is also determined. For example, in the case of a liquid lead-acid battery, it is possible to uniquely calculate the inter-electrode distance from the thickness of the electrode plate group and the number and thickness of each of the negative electrode plate and the positive electrode plate. In the case of a control valve type lead storage battery, the distance between the electrodes is uniquely determined from the thickness of the electrode plate group or the size of the space in which the electrode plate group is housed and the number and thickness of each of the negative electrode plate and the positive electrode plate. Can be calculated.

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described for each main constituent element, but the present invention is not limited to the following embodiment.
(Negative electrode plate)
A negative electrode plate of a lead storage battery includes a negative electrode current collector and a negative electrode material. The negative electrode material is held on the 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 or lead alloy sheet. Examples of the processing method include expanding processing and punching.

The lead alloy used for the negative electrode current collector may be any of a Pb-Sb alloy, a Pb-Ca alloy, and a Pb-Ca-Sn alloy. These lead or lead alloy may further contain at least one element selected from the group consisting of Ba, Ag, Al, Bi, As, Se, Cu and the like as an additional element. The negative electrode current collector may have lead alloy layers having different compositions, and may have a plurality of lead alloy layers.

The negative electrode material contains a predetermined amount of a negative electrode active material (lead or lead sulfate) that develops a capacity by an oxidation-reduction reaction, and the above-mentioned synthetic organic shrink proof agent or an organic shrink proof agent containing 3000 μmol/g or more of sulfur element. Include in quantity. The negative electrode material may further contain a carbonaceous material such as carbon black, barium sulfate or the like as an inorganic shrink-proofing agent, and may further contain other additives as required.

The negative electrode active material in the charged state is spongy lead, but the unformed negative electrode plate is usually produced by using lead powder which is a raw material of the negative electrode active material.

The negative electrode plate can be formed by filling a negative electrode current collector with a negative electrode paste, aging and drying to produce an unformed negative electrode plate, and then forming an unformed negative electrode plate. It is preferable that the unformed negative electrode plate is aged and dried at a temperature higher than room temperature and a high humidity. The negative electrode paste may be prepared by adding water and sulfuric acid to lead powder, an organic shrink proofing agent, and various additives, and kneading the mixture.

The formation can be performed by charging the electrode plate group in a state where the electrode plate group including the unformed negative electrode plate is immersed in the electrolytic solution containing sulfuric acid in the battery case of the lead storage battery. However, the formation may be performed before the lead storage battery or the electrode plate group is assembled. By formation, spongy lead is produced.

(Positive electrode)
The positive electrode plate of the lead storage battery can be classified into a paste type and a clad type.
The paste-type positive electrode plate includes a positive electrode current collector and a positive electrode material. The positive electrode material is held on the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and may be formed by casting lead or a lead alloy or processing a lead or lead alloy sheet.
The clad type positive electrode includes a plurality of porous tubes, a core metal inserted into each tube, a positive electrode material filled in the tube in which the core metal is inserted, and a connecting plate connecting the plurality of tubes. To have.

The lead alloy used for the positive electrode current collector is preferably a Pb-Ca-based alloy, a Pb-Ca-Sn-based alloy, or the like, in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have lead alloy layers having different compositions, and may have a plurality of lead alloy layers. It is preferable to use a Pb-Sb alloy for the core metal.

The positive electrode material contains a positive electrode active material (lead oxide or lead sulfate) that exhibits a capacity by a redox reaction. In addition to the positive electrode active material, the positive electrode material may contain an additive such as tin sulfate or red lead if necessary.

The unformed paste-type positive electrode plate is obtained by filling the positive electrode current collector with the positive electrode paste, aging and drying, as in the case of the negative electrode plate. The positive electrode paste may be prepared by kneading lead powder, an additive, water and sulfuric acid. After that, an unformed positive electrode plate is formed. The clad-type positive electrode plate is formed by filling a porous glass tube in which a core metal is inserted with lead powder or slurry-like lead powder, and connecting a plurality of tubes with a seat.

(Separator)
A nonwoven fabric sheet, a microporous membrane, or the like is used as the separator. The thickness and the number of separators interposed between the negative electrode plate and the positive electrode plate may be appropriately selected according to the distance between the electrodes. The non-woven sheet is a sheet mainly composed of polymer fibers and/or glass fibers, and for example, 60% by mass or more is formed of a fiber component. On the other hand, the microporous membrane is a sheet mainly composed of components other than fiber components, for example, a composition containing polymer powder, silica powder and oil is extruded into a sheet shape, and then oil is extracted to form pores. It is obtained by The material forming the separator is preferably acid resistant, and the polymer component is preferably polyolefin such as polyethylene or polypropylene.

(Electrolyte)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The degree of gelation is not particularly limited. An electrolytic solution in the gel state from a sol having fluidity may be used, or an electrolyte in the gel state having no fluidity may be used. The specific gravity of the electrolytic solution in the fully charged lead storage battery at 20° C. is, for example, 1.1 to 1.35 g/cm ³ , and preferably 1.2 to 1.35 g/cm ³ .

FIG. 1 shows an external appearance of an example of a lead storage battery according to an embodiment of the present invention.
The lead storage battery 1 includes a battery case 12 that contains an electrode plate group 11 and an electrolytic solution (not shown). The inside of the battery case 12 is partitioned into a plurality of cell chambers 14 by partition walls 13. One electrode plate group 11 is housed in each cell chamber 14. The opening of the battery case 12 is sealed with a lid 15 having a negative electrode terminal 16 and a positive electrode terminal 17. The lid 15 is provided with a liquid port plug 18 for each cell chamber. When replenishing water, the liquid port plug 18 is removed to replenish the replenishing water. The liquid port plug 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 a plurality of positive electrode plates 3 with a separator 4 in between. Here, the bag-shaped separator 4 that accommodates 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 6 that connects the plurality of negative electrode plates 2 in parallel is connected to the through-connecting body 8, and the positive electrode shelf 5 that connects the plurality of positive electrode plates 3 in parallel. It is connected to the positive pole 7. The positive pole 7 is connected to a positive terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative pole 6 is connected to the negative pole 9, and the positive pole 5 is connected to the through connection body 8. The negative pole 9 is connected to a negative terminal 16 outside the lid 15. Each penetrating body 8 passes through a through hole provided in the partition wall 13 and connects the electrode plate groups 11 of the adjacent cell chambers 14 in series.

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

<<Example 1>>
(1) Preparation of Negative Electrode Plate Raw material lead powder, barium sulfate, carbon black, and a predetermined amount of a synthetic organic shrink proof agent were mixed with an appropriate amount of sulfuric acid aqueous solution to obtain a negative electrode paste. 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 unformed negative electrode plate.

The synthetic organic shrink proofing agent was added to the negative electrode paste so that the content of the synthetic organic shrink proofing agent in the negative electrode material of the lead storage battery that had been fully charged after chemical formation was 0.2% by mass. Further, the amount of water and the amount of sulfuric acid blended in the negative electrode paste were controlled so that the density of the negative electrode material of the fully charged lead storage battery after formation was 3.3 g/cm ³ .
Here, the density of the negative electrode material was measured by the method described above after the lead storage battery after chemical formation was fully charged and then disassembled. As the measuring device, an automatic porosimeter, Autopore IV9505 manufactured by Shimadzu Corporation was used.

As the synthetic organic shrinkproofing agent, a condensate of bisphenols having sulfonic acid groups introduced therein with formaldehyde was used. Here, the amount of sulfonic acid groups to be introduced was controlled so that the content of elemental sulfur in the synthetic organic shrink-proofing agent was 4000 μmol/g.

(2) Preparation of positive electrode plate Lead oxide powder as a raw material was mixed with a sulfuric acid aqueous solution to obtain a positive electrode paste. 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 unformed positive electrode plate.

(3) Production of Lead Acid Battery An unformed negative electrode plate was housed in a bag-shaped separator formed of a polyethylene microporous film, and an electrode plate group was formed by 5 negative electrode plates and 4 positive electrode plates. However, a plurality of types of electrode plate groups having different inter-electrode distances were produced so that the inter-electrode distance in the fully charged lead-acid battery after formation was 0.4 mm to 1.8 mm and changed at 0.2 mm intervals. The distance between the electrodes was controlled by the pitch of each electrode plate connected to the positive electrode shelf and the negative electrode shelf.

The electrode plate group was housed in a polypropylene battery case together with the electrolytic solution and was subjected to chemical formation in the battery case to assemble a liquid lead acid battery for automobiles for each electrode plate group having a different distance between electrodes. The output of the lead storage battery is 12V, and the rated 5-hour rate capacity is 55Ah. In addition, the lead storage battery using the electrode plate group in which the distance between the electrodes is less than 1 mm is a reference example.

<<Comparative Example 1>>
A plurality of kinds of electrode plate groups having different distances between the electrodes were prepared in the same manner as in Example 1 except that lignin derived from a natural product and having a sulfur element content of 600 μmol/g was used in place of the synthetic organic shrink-proofing agent. Was prepared and a lead storage battery was assembled.

[Evaluation 1]
With respect to the lead storage batteries produced in Example 1 and Comparative Example 1, a heavy load life test was performed under the following conditions according to JIS D5301:2006.
<Cycle conditions>
Discharge: 20 A x 1 hour, charge: 5 A x 5 hours However, continuous discharge is performed every 25 cycles until the terminal voltage becomes 10.2V.

The amount of fall of the positive electrode material at the time of 200 cycles of the heavy load life test was measured as follows. First, an initial already formed fully charged lead storage battery was disassembled, the positive electrode plate was taken out, the sulfuric acid was removed by washing with water, and dried, and the mass A of the positive electrode plate was measured. On the other hand, the positive electrode plate was taken out from the lead storage battery after 200 cycles of the heavy load life test, and its mass B was similarly obtained. From the difference between A and B, the amount of fall of the positive electrode material (active material) was calculated by the following formula.
Dropping amount (%) of positive electrode material={(A−B)/A}×100

The relationship between the distance between the electrodes and the amount of fall of the positive electrode material is shown in Table 1 and FIG. It can be said that the larger the amount of the positive electrode material dropped out at the time of 200 cycles, the more the softening of the positive electrode material due to the organic shrink proofing agent eluted in the electrolytic solution progresses, and the more the positive electrode plate deteriorates.

In FIG. 2, when the synthetic organic shrink-proofing agent is used, the smaller the inter-electrode distance is less than 0.9 mm, the larger the amount of the positive electrode material dropped. Further, with the interelectrode distance of 0.9 mm as a boundary, a reversal phenomenon is observed between the synthetic organic shrink proofing agent and the lignin in the dependence of the amount of the positive electrode material dropped on the interelectrode distance. That is, when lignin is used, if the distance between the electrodes is set to 0.9 mm or more, the amount of the positive electrode material dropped tends to increase. From the above, it can be understood that the fact that the positive electrode material is frequently dropped is a phenomenon peculiar to the use of the synthetic organic shrink proofing agent, and that the phenomenon can be suppressed by setting the distance between the electrodes to 0.9 mm or more.

<<Example 2>>
In the lead-acid battery fully charged after formation, the inter-electrode distance was 1.2 mm and the density of the negative electrode material was 3.3 g/cm ³ , while the content of the synthetic organic shrink proofing agent in the negative electrode material was 0. It was changed in the range of 0.05% by mass to 0.3% by mass. Except for the above, an electrode plate group was prepared in the same manner as in Example 1, a lead storage battery was assembled, and the same evaluation as in Evaluation 1 was performed.

<<Comparative example 2>>
In the lead storage battery fully charged after formation, the distance between the electrodes was 1.2 mm and the density of the negative electrode material was 3.3 g/cm ³ , while the content of lignin in the negative electrode material was 0.05 mass. % To 0.3% by mass. Except for the above, an electrode plate group was prepared in the same manner as in Comparative Example 1, a lead storage battery was assembled, and the same evaluation as in Evaluation 1 was performed.

Regarding Example 2 and Comparative Example 2, Table 2 and FIG. 3 show the relationship between the content of the organic shrink-proofing agent in the negative electrode material and the falling amount of the positive electrode material. FIG. 3 shows that even if the content of the organic anti-shrink agent is changed within a predetermined range, the amount of the positive electrode material removed is not significantly affected.

<<Example 3>>
The content of elemental sulfur contained in the synthetic organic anti-shrink agent is 3000 μmol/g, 4000 μmol/g or 6000 μmol/g, and the inter-electrode distance of the lead storage battery fully charged after formation is finely changed within a range of 0.3 to 1.8 mm. Let Except for the above, in the same manner as in Example 1, a plurality of types of electrode plate groups having different inter-electrode distances were produced and a lead storage battery was assembled.

[Evaluation 2]
With respect to the lead-acid battery manufactured in Example 3, the same heavy load life test as described above was performed, and the cycle when the capacity when continuously discharged until the terminal voltage became 10.2 V became 50% of the 5-hour rate discharge capacity was cycled. The number was measured. The relationship between the distance between the electrodes and the number of cycles is shown in Table 3 and FIG.

From FIG. 4, it can be understood that the heavy load life performance tends to decrease as the inter-electrode distance decreases below 0.9 mm, regardless of the content of the elemental sulfur contained in the organic anti-shrink agent. However, this tendency becomes more remarkable as the content of the elemental sulfur contained in the organic shrink-proofing agent is smaller. On the other hand, when the distance between the electrodes is 0.9 mm or more (particularly 1.0 mm or more or 1.2 mm or more), the heavy load life performance is stabilized at a high level, and especially the content of the sulfur element contained in the organic shrink proofing agent. Is 3000 μmol/g or more, and further 4000 μmol/g or more, excellent heavy load life performance is obtained. In addition, it is considered that the reduction of the amount of the positive electrode material dropped greatly influences the improvement of the heavy load life performance. Therefore, regardless of the content of the elemental sulfur contained in the synthetic organic anti-shrink agent, the same tendency as in FIG. 2 or the phenomenon of reversal of lignin in the dependence of the amount of the positive electrode material dropped off on the inter-electrode distance occurs. Conceivable.

<<Example 4>>
In the lead-acid battery fully charged after formation, the distance between the electrodes was set to 1.0 mm and the density of the negative electrode material was unified to 3.3 g/cm ³ , while the content of elemental sulfur contained in the synthetic organic shrink proofing agent was changed. It was finely changed in the range of 3000 to 7500 μmol/g. Except for the above, in the same manner as in Example 1, a plurality of types of electrode plate groups having different sulfur element contents in the synthetic organic shrink proofing agent were prepared and a lead storage battery was assembled.

[Evaluation 3]
Regarding the lead-acid battery manufactured in Example 4, the lead-acid battery was discharged at a low-temperature high-rate (low-temperature HR) discharge duration at −15° C. under a discharge current of 150 A, and the inter-terminal voltage was reduced to 6.0 V. The number of seconds was measured. Table 4 and FIG. 5 show the relationship between the content of elemental sulfur in the organic anti-shrink agent and the low-temperature high-rate discharge duration.

From FIG. 5, it can be understood that in order to improve the low-temperature high-rate discharge performance, it is advantageous to set the content of the sulfur element in the organic anti-shrink agent to 3500 μmol/g or more, and further to 4000 μmol/g or more.

<<Example 5>>
In the lead-acid battery fully charged after formation, the distance between the electrodes was set to 1.0 mm and the density of the negative electrode material was unified to 3.3 g/cm ³ , while the content of elemental sulfur contained in the synthetic organic shrink proofing agent was changed. It was changed in the range of 500 to 8000 μmol/g. Except for the above, in the same manner as in Example 1, a plurality of kinds of electrode plate groups having different sulfur element contents of the synthetic organic shrink proofing agent were prepared and a lead storage battery was assembled.

[Evaluation 4]
With respect to the lead storage battery manufactured in Example 5, the amount of the organic shrinkproofing agent eluted from the negative electrode plate was measured. Here, the negative electrode plate was taken out from the lead-acid battery at the time of 200 cycles of the heavy load life test, the content C1 of the organic shrink proof agent in the negative electrode material was measured, and the organic shrink proof agent content C2 was compared with the initial content of the organic shrink proof agent. The elution amount of the shrinkproofing agent was calculated by the following formula. Table 5 and FIG. 6 show the relationship between the content of elemental sulfur in the organic anti-shrink agent and the elution amount of the organic anti-shrink agent.
Elution amount (%)={1-(C1/C2)}×100

According to FIG. 6, when the content of the elemental sulfur in the organic anti-shrink agent is 2000 μmol/g or more, further 3000 μmol/g or more, the elution amount of the organic anti-shrink agent is remarkably reduced, especially when it is 4000 μmol/g or more. It can be understood that is stabilized in a small amount.

<<Example 6>>
In the lead-acid battery fully charged after formation, the inter-electrode distance is unified to 1 mm, and the content of the sulfur element contained in the synthetic organic shrink proof agent is unified to 3000 μmol/g, 4000 μmol/g or 8000 μmol/g, while The density of the negative electrode material was changed in the range of 2.5 to 4.0 g/cm ³ . Except for the above, in the same manner as in Example 1, a plurality of types of electrode plate groups having different negative electrode material densities were prepared, a lead storage battery was assembled, and the same evaluation as in Evaluation 2 was performed.

Regarding Example 6, the relationship between the density of the negative electrode material containing various organic shrink-proofing agents and the heavy load life performance is shown in Table 6 and FIG. 7.

In FIG. 7, when the content of the elemental sulfur in the organic anti-shrink agent is 3000 μmol/g, the lower the density of the negative electrode material, the lower the heavy load life performance. On the other hand, when the content of the elemental sulfur in the organic anti-shrink agent is 4000 μmol/g or more, even if the density of the negative electrode material becomes small, the heavy load life performance hardly deteriorates and the good performance is maintained. .. That is, when the content of the sulfur element in the organic anti-shrink agent is 4000 μmol/g or more, a remarkable difference is observed in the dependence of the heavy load life performance on the density of the negative electrode material, as compared with the case of 3000 μmol/g. .. The organic anti-shrink agent having a sulfur element content of 4000 μmol/g or more is particularly useful when trying to achieve good heavy load life performance with a low-density negative electrode material.

<<Example 7>>
As in Example 1, except that a condensate of naphthalene with formaldehyde having a content of elemental sulfur of 4000 μmol/g (naphthalene-based organic anti-shrink agent) was used as the organic anti-shrink agent, the electrode when fully charged after formation A lead storage battery was assembled with a negative electrode plate having a distance of 1 mm and a negative electrode material density of 3.3 g/cm ³ .

[Evaluation 4]
The lead acid battery prepared in Example 7 and the lead acid battery prepared in Example 1 using the condensate of bisphenol with formaldehyde (bisphenol organic shrinkage inhibitor) having a sulfur element content of 4000 μmol/g were evaluated 1, Similarly to 3, the heavy load life cycle number and the low temperature high rate discharge duration were measured. The results are shown in Table 1.

It can be understood from Table 1 that substantially the same results can be obtained even when the organic anti-shrink agent is a naphthalene type, when the organic anti-shrink agent is a bisphenol type.

INDUSTRIAL APPLICABILITY The present invention is applicable to both liquid type and control valve type lead storage batteries, and is suitably used as a power source for automobiles, motorcycles, electric vehicles (forklifts, etc.), and industrial power storage devices.

DESCRIPTION OF SYMBOLS 1 Lead acid battery, 2 negative electrode plate, 3 positive electrode plate, 4 separator, 5 positive electrode shelf, 6 negative electrode shelf, 7 positive electrode column, 8 through connection body, 9 negative electrode column, 11 electrode plate group, 12 battery case, 13 partition wall, 14 cell Chamber, 15 lid, 16 negative electrode terminal, 17 positive electrode terminal, 18 liquid stopper

Claims (5)

A negative electrode plate, a positive electrode plate, and an electrolytic solution,
The negative electrode plate includes a negative electrode current collector and a negative electrode material,
The negative electrode material contains a synthetic organic shrink proofing agent,
The synthetic organic shrink-proofing agent contains elemental sulfur of 3000 μmol/g or more,
Lead acid battery whose distance between the said negative electrode plate and the said positive electrode plate is 0.9 mm or more and 2 mm or less. The lead acid battery according to claim 1 , wherein the synthetic organic shrink-proofing agent contains elemental sulfur of 4000 μmol/g or more. A negative electrode plate, a positive electrode plate, and an electrolytic solution,
The negative electrode plate includes a negative electrode current collector and a negative electrode material,
The negative electrode material contains an organic shrink-proofing agent,
The distance between the negative electrode plate and the positive electrode plate is 0.9 mm or more and 2 mm or less,
The lead storage battery, wherein the organic anti-shrink agent contains elemental sulfur of 3000 μmol/g or more. The lead acid battery according to claim 3 , wherein the organic anti-shrink agent contains 4000 μmol/g or more of elemental sulfur. The density of the negative electrode material, 2.5 g / cm ³ or more and is 4.0 g / cm ³ or less, lead-acid battery according to any one of claims 1-4.

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