JP2018018802A - Lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead-acid battery excellent in durability of a positive electrode plate and excellent in life performance.SOLUTION: A lead-acid battery 1 includes a negative electrode plate 2, a positive electrode plate 3, a separator 4s interposed between the negative electrode plate 2 and the positive electrode plate 3, and an electrolyte. The negative electrode plate 2 includes a negative electrode collector and a negative electrode material. The negative electrode material contains an organic shrink-proofing agent. Nonwoven fabric mats 4a and 4c are interposed between the negative electrode plate 2 and the separator 4s and between the positive electrode plate 3 and the separator 4s, respectively. A service life is improved when a void ratio of the negative electrode material is 0.15-0.22 cm/g, or low-rate discharge performance is improved when the void ratio is 0.22-0.27 cm/g.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are used in various applications in addition to in-vehicle and industrial applications. The lead storage battery includes a positive electrode plate, a negative electrode plate, a separator interposed between the positive electrode plate and the negative electrode plate, and an electrolytic solution containing sulfuric acid. The negative electrode plate includes a negative electrode current collector and a negative electrode material, and the positive electrode plate includes a positive electrode current collector and a positive electrode material.

  The negative electrode material contains an active material (cavernous lead or lead sulfate) that develops capacity by an oxidation-reduction reaction. In the negative electrode plate, the lead sulfate reduction reaction proceeds during charging, but lead sulfate is difficult to be reduced to spongy lead. Therefore, sulfation in which lead sulfate crystals grow gradually proceeds. Further, at the time of charging, the sulfuric acid concentration in the electrolyte around the electrode plate is high, and the sulfuric acid solution having a partially high concentration tends to settle to the lower part of the battery. Since these phenomena reduce the life performance of lead-acid batteries, various countermeasures have been studied as follows.

  Patent Document 1 teaches that a negative electrode material contains a bisphenol condensate as an organic shrinking agent.

  Patent Document 2 proposes that the porosity of the negative electrode active material be 0.22 mL / g or more and 0.4 mL / g or less.

  Patent Document 3 proposes that a non-woven fabric made of fibers of a material such as glass is brought into contact with the negative electrode plate.

Patent Document 4 discloses that in a sealed lead-acid battery, the maximum pore diameter of a porous electrolyte holder mainly composed of acid-resistant inorganic powder and glass fiber is set to less than 30 μm, or the specific surface area is 5 to 80 m ² / g. It is proposed that The contact angle of the electrolytic solution holder with respect to dilute sulfuric acid is 30 to 70 degrees.

International Publication No. 2015/181865 Pamphlet JP 2014-123525 A International Publication No. 2012/157311 Pamphlet Japanese Patent Laid-Open No. 3-122966

  Some of the organic shrinking agent added to the negative electrode plate tends to elute into the electrolyte and soften the positive electrode material. When the positive electrode material is softened, the durability of the positive electrode plate is lowered, and the positive electrode material is easily dropped from the positive electrode current collector. Such deterioration of the positive electrode plate decreases the life performance of the lead storage battery.

  One aspect of the present invention includes a negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the positive electrode plate, and an electrolyte solution. The negative electrode plate includes a negative electrode current collector, a negative electrode, An electrode material, and the negative electrode material contains an organic shrinkage agent, and a nonwoven fabric mat is interposed between the negative electrode plate and the separator and between the positive electrode plate and the separator, It relates to a lead-acid battery.

  ADVANTAGE OF THE INVENTION According to this invention, the lead storage battery excellent in lifetime performance can be provided because durability of a positive electrode plate improves.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an exploded perspective view of a lead-acid battery according to an embodiment of the present invention, showing an appearance and an internal structure, with a part cut away. It is a figure which shows the relationship between content of the sulfur (S) element in an organic shrunk | reducing agent, and the amount of falling-off of positive electrode material. It is a figure which shows the relationship between content of the elemental sulfur in an organic shrinking agent, and the amount of lead sulfate accumulation in the lower part of a negative electrode plate. It is a figure which shows the relationship between content of the elemental sulfur in an organic preshrink agent, and the number of life cycles. It is a figure which shows the relationship between the presence or absence of a nonwoven fabric mat, and the number of life cycles. It is a figure which shows the relationship between the space | gap ratio of negative electrode material, and the number of life cycles. It is a figure which shows the relationship between content of the sulfur element in an organic shrinking agent, and a 5-hour rate (0.2CA) discharge duration. It is a figure which shows the relationship between the presence or absence of a nonwoven fabric mat, and 5 hour rate discharge duration. It is a figure which shows the relationship between the space | gap ratio of negative electrode material, and 5 hour rate discharge duration. It is a figure which shows the relationship between content of the sulfur element in an organic contraction agent when changing the contact angle of the electrolyte solution with respect to a nonwoven fabric mat, and a lifetime cycle number. It is a figure which shows the relationship between content of the sulfur element in an organic shrinkage | condensation agent when changing the contact angle of the electrolyte solution with respect to a nonwoven fabric mat, and 5 hour rate discharge duration.

A lead storage battery according to one aspect of the present invention includes a negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the 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 includes an organic anti-shrink agent. Nonwoven fabric mats are interposed between the negative electrode plate and the separator and between the positive electrode plate and the separator, respectively. It is preferable that the nonwoven fabric mat is not integrated with the positive electrode plate and the negative electrode plate and is disposed in contact with the positive electrode plate and the negative electrode plate, respectively.
As an embodiment of the present invention, a liquid (vented) lead acid battery is more suitable than a control valve (sealed) lead acid battery.

  Since the organic shrunk agent reduces the specific resistance of the negative electrode material, it can be expected to improve the high-rate discharge performance of the lead-acid battery at a low temperature and the charge acceptance performance of the negative electrode plate.

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

As a specific example of the organic shrinking agent, a condensate of formaldehyde with a compound having a sulfur-containing group and one or more, preferably two or more aromatic rings is preferable. As the compound having two or more aromatic rings, bisphenols, biphenyls, naphthalenes and the like are preferably used. Bisphenols, biphenyls and naphthalenes are generic names for compounds having a bisphenol skeleton, biphenyl skeleton and naphthalene skeleton, respectively, and each may have a substituent. These may be contained alone in the organic shrinking agent, or a plurality of types may be contained. As bisphenol, bisphenol A, bisphenol S, bisphenol F and the like are preferable. Among them, since bisphenol S has a sulfonyl group (—SO ₂ —) in the bisphenol skeleton, it is easy to increase the content of elemental sulfur.

  Even if the condensate of bisphenols experiences a temperature environment higher than normal temperature, its performance at low temperature is not impaired, so it can be used for lead-acid batteries (such as liquid lead-acid batteries for automobiles) placed in a temperature environment higher than normal temperature. Is suitable. The condensate of naphthalene sulfonic acid is less likely to have a smaller polarization than the condensate of bisphenols, and is therefore suitable for a lead storage battery in which liquid reduction characteristics are important.

  The sulfur-containing group may be directly bonded to an aromatic ring such as bisphenols, biphenyls, and naphthalenes. For example, the sulfur-containing group may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group. A monocyclic compound such as aminobenzenesulfonic acid or alkylaminobenzenesulfonic acid may be condensed with formaldehyde together with a compound having two or more aromatic rings.

  Condensates of N, N ′-(sulfonyldi-4,1-phenylene) bis (1,2,3,4-tetrahydro-6-methyl-2,4-dioxopyrimidine-5-sulfonamide) and the like are organic It may be used as an anti-shrink agent.

  If the content of the organic shrunk agent contained in the negative electrode material is within a general range, the action of the organic shrunk agent does not greatly influence. The content of the organic shrinking 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, still more preferably 0.05% by mass or more, while 1.0% % By mass or less is preferred, 0.8% by mass or less is more preferred, and 0.3% by mass or less is still more preferred. Here, the content of the organic shrinking agent contained in the negative electrode material is a content in the negative electrode material collected by a method described later from a lead-acid battery in a fully formed state.

  From the viewpoint of reducing the specific resistance of the negative electrode material, increasing the utilization of the electrode material, and enhancing the effect of improving the low rate discharge capacity, the content of the sulfur element in the organic shrinkage agent is preferably 2000 μmol / g or more. More preferably, it is 3000 μmol / g or more, more preferably 4000 μmol / g or more, and particularly preferably 6000 μmol / g or more. However, it is difficult to excessively increase the content of elemental sulfur in the organic shrinking agent. The content of elemental sulfur in the organic shrinking agent may be 10000 μmol / g or less, preferably 9000 μmol / g or less, and more preferably 8000 μmol / g or less. In addition, the content of the elemental sulfur in the organic shrinking agent being X μmol / g means that the content of the elemental sulfur contained in 1 g of the organic shrinking agent is X μmol.

  On the other hand, a part of the organic anti-shrink agent tends to elute into the electrolyte and soften the positive electrode material. The amount of dropping from the positive electrode current collector due to the softening of the positive electrode material is more likely to increase as the content of the elemental sulfur in the organic anti-shrink agent increases.

  On the other hand, when a nonwoven fabric mat is interposed between the negative electrode plate and the separator and between the positive electrode plate and the separator, the falling of the positive electrode material from the positive electrode current collector is remarkably suppressed. One reason why the positive electrode material is prevented from falling off is considered to be that the non-woven mat interposed between the positive electrode plate and the separator makes the positive electrode material less susceptible to gas generation. For example, the nonwoven fabric mat physically suppresses the generated gas from contacting the positive electrode material. Thereby, softening of the positive electrode material is suppressed.

  Here, although the reason is not clear, the effect of suppressing the loss of the positive electrode material is notable between the positive electrode plate and the separator, but also by interposing the nonwoven fabric mat between the negative electrode plate and the separator. Enhanced. On the other hand, for the same reason, although the reason is not clear, even if a non-woven mat is interposed only between the negative electrode plate and the separator, the effect of suppressing the loss of the positive electrode material is hardly obtained.

  The nonwoven fabric mat interposed between the negative electrode plate and the separator not only enhances the effect of suppressing the detachment of the positive electrode material, but also suppresses the precipitation of sulfate ions generated during charging from the negative electrode plate, thereby stratifying the electrolyte. It is also considered to have an inhibitory effect. Thereby, the charge acceptance performance in the lower part of a negative electrode plate improves, and sulfation is suppressed. It is considered that the life performance of the lead storage battery is remarkably improved by the synergistic action of these effects.

The effect of improving the life performance is that a nonwoven fabric mat is interposed between the negative electrode plate and the separator and between the positive electrode plate and the separator, respectively, and the void ratio of the negative electrode material is 0.15 cm ³ / g or more and 0.22 cm. ^It can be further increased by setting it to ³ / g or less. In this case, the density of the negative electrode material is approximately 4.0g / cm ³ ~3.2g / cm ³ order. Among these, when the content of the elemental sulfur in the organic shrinking agent is 4000 to 8000 μmol / g (more preferably 6000 to 8000 μmol / g), the life performance is remarkably improved. The negative electrode material having a void ratio of 0.15 to 0.22 cm ³ / g has a lower specific resistance, and the specific resistance of the negative electrode material is also reduced by the action of the organic shrinking agent. Therefore, it is considered that the life performance is easily improved.

On the other hand, the void ratio of the negative electrode material 0.22 cm ³ / g or more, in the case of below 0.27 cm ³ / g, the low-rate discharge performance (such as discharge duration at 5 hour rate) is significantly improved . In this case, the density of the negative electrode material is approximately 3.2g / cm ³ ~2.5g / cm ³ order. In particular, when the content of the elemental sulfur in the organic shrinking agent is 4000 to 8000 μmol / g (more preferably 6000 to 8000 μmol / g), the low rate discharge performance is particularly remarkably improved. Since the high-porosity negative electrode material has a high utilization factor, the low-rate discharge performance is improved, and the specific resistance of the negative electrode material is also lowered by the action of the organic shrinking agent. Thereby, it is considered that the low-rate discharge performance is easily improved.

Void ratio of the negative electrode material is 0.15 cm ³ / g or more, when following 0.27 cm ³ / g, median pore diameter distribution based on volume is preferably, for example, 0.1 m to 10 m.

Hereinafter, although the lead storage battery which concerns on embodiment of this invention is demonstrated for every main component requirement, this 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 additive element. The negative electrode current collector may have lead alloy layers having different compositions, and a plurality of lead alloy layers may be provided.

  The negative electrode material contains a predetermined amount of a negative electrode active material (lead or lead sulfate) that develops capacity by an oxidation-reduction reaction, and the above-described synthetic organic shrinkage agent or an organic shrinkage agent containing 4000 μmol / g or more of elemental sulfur. Include in quantity. The negative electrode material may further contain a carbonaceous material such as carbon black, barium sulfate, and the like, and may contain other additives as necessary.

  The negative electrode active material in a charged state is spongy lead, but the unformed negative electrode plate is usually produced using lead powder as a raw material for 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. The negative electrode paste is prepared by adding and kneading water and sulfuric acid to lead powder, an organic anti-shrink agent, and various additives. At this time, it is preferable to age at room temperature and high humidity.

  The chemical conversion can be performed by charging the electrode plate group in a state in which the electrode plate group including the unformed negative electrode plate is immersed in an electrolytic solution containing sulfuric acid in the battery case of the lead storage battery. However, the chemical conversion may be performed before the assembly of the lead storage battery or the electrode plate group. Sponge-like lead is generated by chemical conversion.

(Positive electrode)
The positive electrode plate of the lead storage battery can be classified into a paste type, a clad type and the like.
The paste type positive electrode plate generally includes a positive electrode current collector and a positive electrode material. The positive electrode material is held by the positive electrode current collector. The positive electrode current collector may be formed in the same manner as the negative electrode current collector, and can be formed by casting lead or a lead alloy or processing a lead or lead alloy sheet.
The clad 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 joint that connects the plurality of tubes. It has.

  As a lead alloy used for the positive electrode current collector, a Pb—Ca alloy, a Pb—Ca—Sn alloy, or the like is preferable in terms of corrosion resistance and mechanical strength. The positive electrode current collector may have lead alloy layers having different compositions, and a plurality of lead alloy layers may be provided. It is preferable to use a Pb—Sb alloy for the cored bar.

  The positive electrode material includes a positive electrode active material (lead oxide or lead sulfate) that develops capacity by an oxidation-reduction reaction. In addition to the positive electrode active material, the positive electrode material may include additives such as tin sulfate and red lead as necessary.

  The unformed paste-type positive electrode plate is obtained by filling a positive electrode current collector with a positive electrode paste, aging and drying in the same manner as in the case of the negative electrode plate. Thereafter, an unformed positive electrode plate is formed. The positive electrode paste is prepared by kneading lead powder, additives, water, and sulfuric acid. The clad positive electrode plate is formed by filling a porous tube into which a core metal is inserted with lead powder or slurry-like lead powder, and joining a plurality of tubes together.

(Electrolyte)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled as necessary. The degree of gelation is not particularly limited. A gel electrolyte may be used from a fluid sol, or a gel electrolyte without fluid may be used. The specific gravity at 20 ° C. of the electrolyte in a fully charged lead-acid battery is, for example, 1.10 to 1.35 g / cm ³ , and preferably 1.20 to 1.35 g / cm ³ .

(Nonwoven fabric mat)
The nonwoven fabric mat is a sheet in which fiber materials that are insoluble in the electrolytic solution are intertwined without being woven. As the fiber material, glass fiber, polymer fiber, pulp fiber, or the like can be used. Of the polymer fibers, polyolefin fibers are preferred. The nonwoven fabric mat may contain components other than the fiber material, for example, an acid-resistant inorganic powder, a polymer as a binder, and the like. As the inorganic powder, silica powder, glass powder, diatomaceous earth, or the like can be used. However, the content of the fiber material is preferably 5% by mass or more, more preferably 10% by mass or more, or 30% by mass or more from the viewpoint of uniformly diffusing an abundant electrolyte in the pores of the nonwoven fabric mat.

  The average fiber diameter of the fiber material which comprises a nonwoven fabric mat is 0.1 micrometer-25 micrometers, for example. The average particle diameter of the inorganic powder constituting the nonwoven fabric mat is, for example, 1 μm to 100 nm. These average values can be obtained from an enlarged photograph of the selected fiber by arbitrarily selecting 10 or more fibers or 10 or more particles. The particle diameter of the particle is the diameter of an equivalent circle having the same area as the projected area of the particle that can be confirmed by an enlarged photograph.

  The contact angle θm of the electrolyte solution with respect to the nonwoven fabric mat is preferably 0 ° to 40 °, more preferably less than 30 °, and still more preferably 25 ° or less. By setting the contact angle θm to 40 ° or less, the diffusibility of the electrolytic solution into the pores of the nonwoven fabric mat is improved, and the life performance and the low rate discharge performance are more easily improved. In particular, when the content of the elemental sulfur in the organic shrinking agent is 4000 to 8000 μmol / g (more preferably 6000 to 8000 μmol / g), the contact angle θm is set to 0 ° to 40 °, so that the life performance and the low rate are achieved. Discharge performance is significantly improved.

  The contact angle θm can be controlled by surface treatment of the nonwoven fabric mat. For example, the contact angle θm can be reduced to 40 ° or less by hydrophilizing the surface of the nonwoven fabric mat. Examples of the hydrophilization treatment include applying a coating to the surface of the non-woven mat or plasma-treating the surface of the non-woven mat.

  The thickness of the nonwoven fabric mat may be appropriately selected according to the size of the lead storage battery, the thickness of the positive electrode plate and the negative electrode plate, and may be selected from a range of 0.1 mm to 2 mm, for example.

(Separator)
A microporous membrane is used for the separator. The microporous membrane is a sheet mainly composed of materials other than the fiber material, for example, by extruding a composition containing polymer powder, silica powder and oil into a sheet shape, and then extracting the oil to form pores. can get. The polymer component constituting the separator preferably has acid resistance, and polyolefins such as polyethylene and polypropylene are preferred. Although a trace amount of fiber material may be included in the microporous membrane, the content of the fiber material is preferably 20% by mass or less.

  The thickness of the separator may be appropriately selected according to the size of the lead storage battery, the thickness of the positive electrode plate and the negative electrode plate, and may be selected from a range of thickness of 0.4 mm to 1.3 mm, for example. In addition, when a separator has an unevenness | corrugation on the surface, the thickness of the part which has a convex part should just be in the said range. For example, in the case of a separator having a base having a uniform thickness and a plurality of ribs protruding from the main surface, the total thickness of the base and ribs may be within the above range. Two or more separators may be laminated and used, or two or more separators may be bonded and integrated.

Next, a method for analyzing each physical property will be described.
(1) Void ratio of negative electrode material The battery after chemical conversion is fully charged and disassembled, and the obtained negative electrode plate is washed with water and dried to remove the electrolyte in the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an unground measurement sample. The measurement sample is degassed using a vacuum pump, and the mass of the measurement sample is measured with an electronic balance and then immersed in ion-exchanged water and / or distilled water stabilized at 20 ° C. ± 0.1 ° C. From the difference in mass of the measurement sample before and after immersion and the value of the true density of water, the volume of water that has entered the void inside the measurement sample can be determined. The void ratio of the negative electrode material is obtained by dividing the volume of the obtained water by the mass of the measurement sample before immersion.

The auxiliary charging conditions for fully charging the lead storage battery are as follows.
In the case of a liquid battery, constant current charging is performed until reaching 2.5 V / cell at 0.2 CA in a water bath at 25 ° C., and then constant current charging is further performed at 0.2 CA for 2 hours.
In the case of a VRLA battery (control valve type lead-acid battery), constant current / constant voltage charging at 25 ° C., 0.2 CA, 2.23 V / cell in an air tank was performed, and the charging current during constant voltage charging became 1 mCA or less. End charging at that time.
1CA in this specification is a current value for discharging the nominal capacity of the battery in one hour. For example, if the battery has a nominal capacity of 30 Ah, 1CA is 30 A, and 1 mCA is 30 mA.

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 conversion is fully charged and disassembled, and the obtained negative electrode plate is washed with water and dried to remove the electrolyte in the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an unground measurement sample. After putting the sample into the measurement 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 obtained. The volume obtained by subtracting the injection volume of mercury from the volume of the measurement container is defined as the bulk volume.

(2) Contact angle of electrolyte solution to non-woven mat In the same manner as described above, a non-woven mat is taken out from a fully charged lead-acid battery, washed and dried, and a sample piece of the non-woven mat is collected. Next, 2 μL of a sulfuric acid aqueous solution having a specific gravity of 1.28 g / cm ³ at 20 ° C. is dropped as a standard electrolyte on the horizontal surface of the collected sample piece, and the image of the formed droplet after 2 seconds is analyzed. Then, the contact angle is measured by the θ / 2 method.

(3) Analysis of Organic Shrinkage Agent First, an already formed lead-acid battery in a fully charged state is disassembled, the 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. Hereinafter, the initial sample is analyzed by the following method.

(3-1) Qualitative property of organic shrinkage agent in negative electrode material The initial sample is immersed in a 1 mol / L NaOH aqueous solution to extract the organic shrinkage agent. Next, insoluble components are removed by filtration from the extracted aqueous NaOH solution containing the organic shrinking agent, and the resulting filtrate is desalted and then concentrated and dried. Desalting may be performed by placing the filtrate in a dialysis tube and immersing it in distilled water. Thereby, a powder sample of the organic shrinking agent is obtained.

  Obtained from the infrared spectroscopic spectrum measured using a powder sample of the organic shrinkage agent thus obtained, and the UV-visible absorption spectrum and NMR spectrum measured with an ultraviolet-visible absorptiometer after the powder sample was dissolved in an appropriate solvent. Information is used in combination to identify the organic pre-shrinking agent species.

(3-2) Quantification of Content of Organic Shrinkage Agent in Negative Electrode Material After obtaining a filtrate of NaOH aqueous solution containing organic shrinkage agent as in (3-1) above, the UV-visible absorption spectrum of the filtrate is measured. To do. Using the spectrum intensity and a calibration curve prepared in advance, the content of the organic shrinking agent in the negative electrode material can be quantified.
When obtaining the battery and measuring the content of the organic shrinkage agent, if the same organic shrinkage agent cannot be used in the calibration curve because the structural formula of the organic shrinkage agent cannot be strictly specified, the negative electrode of the battery By creating a calibration curve using a separately available organic shrinkage agent that shows similar shapes in the UV-visible absorption spectrum, infrared spectrum, and NMR spectrum of the organic shrinkage agent extracted from The content of the organic shrinking agent is measured using the absorption spectrum.

(3-3) Content of Sulfur Element in Organic Shrinkage Agent In the same manner as in (3-1) above, after obtaining a powder sample of the organic shrunk agent, 0.1 g of the organic shrunk agent was obtained by the oxygen combustion flask method The elemental sulfur is converted to sulfuric acid. At this time, an eluate in which sulfate ions are dissolved in the adsorbent is obtained by burning the powder sample in the flask containing the adsorbent. Next, the eluate is titrated with barium perchlorate using thorin as an indicator to determine the content (C1) of elemental sulfur in 0.1 g of the organic shrinking agent. Next, C1 is multiplied by 10, and the content (μmol / g) of elemental sulfur in the organic shrinkage agent per gram is calculated.

In FIG. 1, the external appearance of an example of the lead acid battery which concerns on embodiment of this invention is shown.
The lead storage battery 1 includes a battery case 12 that houses an electrode plate group 11 and an electrolytic solution (not shown). The battery case 12 is partitioned into a plurality of cell chambers 14 by partition walls 13. Each cell chamber 14 accommodates one electrode group 11. 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 plug 18 for each cell chamber. At the time of refilling, the refilling liquid is replenished by removing the liquid stopper 18. The liquid spout 18 may have a function of discharging 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 with a separator 4s, a negative electrode-side nonwoven fabric mat 4a, and a positive electrode-side nonwoven fabric mat 4c, respectively. The negative electrode side nonwoven fabric mat 4 a is attached to both surfaces of the negative electrode plate 2, and the positive electrode side nonwoven fabric mat 4 c is attached to both surfaces of the positive electrode plate 3. Here, although the bag-shaped separator 4 which accommodates the negative electrode plate 2 is shown, the form of a separator is not specifically limited. In the cell chamber 14 located at one end of the battery case 12, the negative electrode shelf 6 connecting the plurality of negative electrode plates 2 in parallel is connected to the through connection body 8, and the positive electrode shelf 5 connecting the plurality of positive electrode plates 3 in parallel is provided. 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 electrode column 9 is connected to the negative electrode shelf 6, and the through connector 8 is connected to the positive electrode shelf 5. The negative pole 9 is connected to the negative terminal 16 outside the lid 15. Each through-connector 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.

  EXAMPLES Hereinafter, although this invention is demonstrated further more concretely based on an Example and a comparative example, this invention is not limited to a following example.

Example 1
(1) Production of negative electrode plate The raw material lead powder, barium sulfate, carbon black, and organic anti-shrink 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 a network part of an expanded lattice made of a Pb—Ca—Sn alloy and aged and dried to obtain an unformed negative electrode plate.

The organic shrunk agent was blended in the negative electrode paste so that the content of the organic shrunk agent in the negative electrode material of the lead-acid battery fully charged after chemical conversion was 0.10% by mass. In addition, the amount of water and sulfuric acid to be mixed in the negative electrode paste is adjusted so that the void ratio of the negative electrode material of the lead-acid battery fully charged after chemical conversion is 0.22 cm ³ / g (median value of volume-based pore diameter distribution is 2 μm). Controlled.

  As the organic shrinking agent, a condensate of bisphenols introduced with lignin or sulfonic acid groups 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 organic shrinking agent was 2000 to 8000 μmol / g. The content of sulfur element in lignin was 600 μmol / g.

(2) Production of positive electrode plate The raw material lead powder and sulfuric acid aqueous solution were mixed to obtain a positive electrode paste. The positive electrode paste was filled in a network part of an expanded lattice made of a Pb—Ca—Sn alloy and aged and dried to obtain an unformed positive electrode plate.

(3) Nonwoven fabric mat As the nonwoven fabric mat, a sheet (thickness 0.5 mm) in which glass fibers (average fiber diameter 0.5 μm) and silica powder (average particle diameter 5 nm) were mixed was used. The contact angle of the electrolyte solution with respect to the nonwoven fabric mat was controlled to 20 ° by a hydrophilic treatment.

(4) Separator The separator is a microporous membrane (having ribs) formed by extruding a composition containing polyethylene powder, silica powder and oil into a sheet having a plurality of ribs and then extracting the oil to form pores. Part thickness 0.5 mm) was used. Here, the microporous membrane was folded in two, and two sides intersecting with the crease were welded to produce a bag-shaped separator.

(5) Preparation of lead acid battery The nonwoven fabric mat was affixed on both surfaces of the negative electrode plate, and was further accommodated in a bag-like separator. Moreover, the nonwoven fabric mat was affixed on both surfaces of the positive electrode plate. An electrode plate group was formed by five negative electrode plates and four positive electrode plates.

The electrode plate group was accommodated in a polypropylene battery case together with the electrolytic solution, and chemical conversion was performed in the battery case. Thus, a plurality of types of liquid lead-acid batteries for automobiles having different contents of elemental sulfur in the organic shrinking agent were assembled. The output of the lead storage battery is 12V, and the rated 5-hour rate capacity is 25 Ah. The specific gravity of the electrolytic solution after the formation was 1.28 g / cm ³ .

<< Comparative Example 1 >>
In the same manner as in Example 1, except that the nonwoven fabric mat was not attached to either the positive electrode plate or the negative electrode plate, a plurality of types of lead storage batteries having different sulfur element contents in the organic antishrink agent were assembled.

<< Comparative Example 2 >>
A plurality of types of lead-acid batteries having different sulfur element contents in the organic anti-shrink agent, as in Example 1, except that the nonwoven fabric mat was attached only to both surfaces of the positive electrode plate and the nonwoven fabric mat was not attached to the negative electrode plate. Assembled.

<< Comparative Example 3 >>
A plurality of types of lead-acid batteries having different sulfur element contents in the organic anti-shrink agent, as in Example 1, except that the nonwoven fabric mat was attached only to both surfaces of the negative electrode plate and the nonwoven fabric mat was not attached to the positive electrode plate. Assembled.

[Evaluation 1]
About the lead acid battery of Example 1 and Comparative Examples 1-3, IS life test was done on condition of the following.
<Cycle conditions>
An idling stop (IS) life test defined in SBA S 0101: 2006 was conducted. That is, after discharging for 59 seconds at 45 A from the fully charged state, and further discharging for 1 second at 300 A, a charge / discharge cycle in which the upper limit current was 100 A and constant voltage charging at 14 V for 60 seconds was repeated. In addition, every 3600 cycles, the lead storage battery was suspended by leaving it for 40 to 48 hours. The test was terminated when the voltage after 1 second at 300 A discharge became less than 7.20V.

As described below, the amount of the positive electrode material falling off at the time of 200 cycles was measured. First, a fully charged lead storage battery after initial chemical conversion was disassembled, the positive electrode plate was taken out, sulfuric acid was removed by washing with water, 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 IS life test, and the mass B thereof was determined in the same manner. From the difference between A and B, the amount of the positive electrode material (active material) falling off was calculated from the following formula. It can be said that the more the amount of the positive electrode material dropped off at the 200th cycle, the more the positive electrode material is softened and the positive electrode plate is deteriorated.
Dropout amount of positive electrode material (%) = {(A−B) / A} × 100

  Moreover, the negative electrode plate was taken out from the lead storage battery after 200 cycles of the IS life test, the negative electrode material was collected from the lower part of the negative electrode plate, and the amount of lead sulfate accumulation was measured. First, the collected negative electrode material was washed with water, dried and pulverized. Next, the content of sulfur element in the pulverized negative electrode material (ground sample) was measured using a sulfur element analyzer (for example, S-200 type manufactured by LECO). Next, the content of elemental sulfur in lead sulfate accumulated in the negative electrode material was determined according to the following formula.

Content of elemental sulfur in lead sulfate = (content of elemental sulfur obtained by elemental sulfur analyzer)-(mass of crushed sample (g) x content of organic shrinkage agent (g / g) x organic shrinkage agent Elemental sulfur content (g / g))

  Next, the content of elemental sulfur in the lead sulfate was converted to the amount of lead sulfate, and the lead sulfate concentration (% by mass) per unit mass of the pulverized sample was determined to obtain the lead sulfate accumulation amount. It can be said that sulfation and stratification of electrolyte progressed as the amount of lead sulfate accumulation increased.

  Regarding Example 1 and Comparative Examples 1 to 3, the relationship between the content of the elemental sulfur in the organic shrinking agent and the amount of the positive electrode material falling off from the positive electrode plate is shown in Table 1 and FIG. Table 2 and FIG. 3 show the relationship between the content of elemental sulfur in the organic shrinking agent and the amount of lead sulfate accumulated in the lower part of the negative electrode plate.

  FIG. 2 shows that the larger the content of the elemental sulfur in the organic shrinking agent, the more the positive electrode material is dropped. On the other hand, FIG. 3 shows that the amount of lead sulfate accumulation decreases as the content of sulfur element in the organic shrinkage agent increases. And in Example 1 which stuck the nonwoven fabric mat on both surfaces of the negative electrode plate, and further stuck the nonwoven fabric mat on both surfaces of the positive electrode plate, Comparative Example 1 where no nonwoven fabric mat was stuck on at least one of the positive electrode plate and the negative electrode plate It can be understood that the falling of the positive electrode material is remarkably suppressed and the accumulation of lead sulfate in the lower part of the negative electrode plate is suppressed as compared with ˜3.

  Furthermore, from FIG. 2, in Comparative Example 2 in which the nonwoven fabric mat is attached only to the positive electrode plate, there is a certain effect of suppressing the falling off of the positive electrode material, but Comparative Example 3 in which the nonwoven fabric mat is attached only to the negative electrode plate. Therefore, it can be understood that the effect of suppressing the dropping of the positive electrode material is hardly obtained. On the other hand, it can be understood that the effect of suppressing the loss of the positive electrode material is significantly increased with respect to Comparative Example 2 by pasting the nonwoven fabric mat on both the negative electrode plate and the positive electrode plate.

Example 2
Except that the void ratio of the negative electrode material of lead-acid battery fully charged to after chemical conversion was varied in the range of 0.14cm ³ /g~0.30cm ³ / g, in the same manner as in Example 1, the sulfur in the organic expander agent Several types of lead acid batteries with different element contents were assembled. The contact angle of the electrolyte solution with respect to the nonwoven fabric mat was unified to 20 °.

<< Comparative Example 4 >>
Similar to Comparative Example 1, the content of elemental sulfur in the organic shrinkage agent, except that the void ratio of the negative electrode material of the lead-acid battery fully charged after the formation was 0.20 cm ³ / g or 0.24 cm ³ / g We assembled several types of lead acid batteries.

<< Comparative Example 5 >>
Similar to Comparative Example 2, the content of elemental sulfur in the organic shrinkage agent, except that the void ratio of the negative electrode material of the lead-acid battery fully charged after conversion was 0.20 cm ³ / g or 0.24 cm ³ / g We assembled several types of lead acid batteries.

<< Comparative Example 6 >>
Similar to Comparative Example 3, the content of elemental sulfur in the organic shrinkage agent, except that the void ratio of the negative electrode material of the lead-acid battery fully charged after conversion was 0.20 cm ³ / g or 0.24 cm ³ / g We assembled several types of lead acid batteries.

[Evaluation 2]
Regarding the lead storage batteries prepared in Example 2 and Comparative Examples 4 to 6, the IS life cycle number was measured under the same conditions as described above.

In Table 3 and FIG. 4, regarding Example 2, the relationship between the content of elemental sulfur in the organic shrinking agent and the number of life cycles is shown. Table 4 and FIG. 5 show the relationship between the presence / absence of the nonwoven fabric mat and the number of life cycles when the void ratio of the negative electrode material is 0.20 cm ³ / g. FIG. 6 shows the relationship between the void ratio of the negative electrode material and the number of life cycles.

FIG. 4 shows that from the viewpoint of improving the life performance of the lead-acid battery, it is advantageous to increase the organic shrinkage agent having a small void ratio in the negative electrode material and a large sulfur element content. In particular, it can be seen that when an organic shrinkage agent having a sulfur element content of 4000 μmol / g or more is used, more excellent life performance can be obtained. However, when the void ratio is reduced to 0.14 cm ³ / g, the superiority in the case of low porosity is impaired, so the void ratio is preferably 0.15 cm ³ / g or more.

  FIG. 5 shows that the effect of improving the life performance of lead-acid batteries tends to be particularly high when nonwoven mats are present both between the negative electrode plate and the separator and between the positive electrode plate and the separator. Show. Moreover, the tendency is remarkable when using an organic shrinkage | condensation agent whose content of a sulfur element is 4000 micromol / g or more.

6, when the void ratio of the negative electrode material is 0.15cm ³ /g~0.22cm ³ / g, and the content of sulfur element in the organic expander agent is 4000μmol / g~8000μmol / g The superiority in life performance is shown more prominently.

[Evaluation 3]
Regarding the lead storage batteries prepared in Example 2 and Comparative Examples 4 to 6, the 5-hour rate (0.2 CA) discharge duration was measured under the following conditions.
The 5-hour rate capacity test specified in JIS D5301 (SBA S 0101: 2006) was conducted. That is, after confirming that the temperature of the electrolyte in the central cell chamber is 25 ° C. ± 2 ° C., the terminal voltage is reduced to 10.50 V ± 0.05 V at a current rate of 5 hours (0.2 CA). The battery was discharged, the discharge duration (t) was recorded, and the capacity was determined.

In Table 5 and FIG. 7, regarding Example 2, the relationship between the content of elemental sulfur in the organic shrinking agent and the 0.2CA discharge duration is shown. Table 6 and FIG. 8 show the relationship between the presence / absence of the nonwoven fabric mat and the 0.2CA discharge duration when the void ratio of the negative electrode material is 0.24 cm ³ / g. Further, FIG. 9 shows the relationship between the void ratio of the negative electrode material and the 0.2 CA discharge duration.

FIG. 7 shows that, from the viewpoint of improving the low rate discharge performance (0.2 CA discharge duration) of the lead storage battery, the organic shrinkage agent having a large void ratio in the negative electrode material and a large sulfur element content is increased. Is advantageous. In particular, it can be seen that when an organic shrinking agent having a sulfur element content of 4000 μmol / g or more is used, more excellent low-rate discharge performance can be obtained. However, when the void ratio is increased to 0.30 cm ³ / g, the superiority in the case of high porosity is impaired, so the void ratio is preferably 0.27 cm ³ / g or less.

  FIG. 8 shows that the effect of improving the low rate discharge performance of the lead-acid battery tends to be particularly high when the nonwoven fabric mat is present both between the negative electrode plate and the separator and between the positive electrode plate and the separator. It is shown that. In addition, this tendency is remarkable when an organic shrinkage agent having a sulfur element content of 4000 μmol / g or more is used.

9, when the gap ratio of negative electrode material is 0.22cm ³ /g~0.27cm ³ / g, and the content of sulfur element in the organic expander agent is 4000μmol / g~8000μmol / g The superiority in low rate discharge performance is shown more remarkably. Specifically, in the graph in which the content of the elemental sulfur in the organic shrinking agent is 4000 μmol / g to 8000 μmol / g, there is a change point that is not found in the graph of 600 μmol / g to 2000 μmol / g. The increase in the 0.2CA discharge duration accompanied by such a change point is a characteristic tendency when the content of elemental sulfur in the organic shrinking agent is 4000 μmol / g to 8000 μmol / g.

Example 3
Similar to Example 1 except that the contact angle of the electrolyte solution to the nonwoven fabric mat was changed in the range of 10 ° to 80 ° by changing the surface treatment conditions of the nonwoven fabric mat. Plural kinds of lead storage batteries having different contents were assembled and evaluated in the same manner as in the above evaluations 2 and 3. However, the void ratio of the negative electrode material was unified at 0.22 cm ³ / g.

  Regarding Example 3, Table 7 and FIG. 10 show the relationship between the content of elemental sulfur in the organic anti-shrink agent and the number of life cycles when the contact angle of the electrolytic solution with respect to the nonwoven fabric mat is changed. Table 8 and FIG. 11 show the relationship between the content of sulfur element in the organic shrinkage agent and the 0.2CA discharge duration when the contact angle of the electrolytic solution with respect to the nonwoven fabric mat is changed.

  FIG. 10 shows that from the viewpoint of improving the life performance of the lead-acid battery, it is advantageous to increase the contact angle of the electrolytic solution with respect to the nonwoven fabric mat to 40 ° or less and to increase the organic shrinkage agent having a large sulfur element content. Is shown. Moreover, FIG. 11 has shown that it is advantageous to make the contact angle of the electrolyte solution with respect to a nonwoven fabric mat into 40 degrees or less also from a viewpoint of improving the low rate discharge performance of a lead acid battery. In particular, when the content of elemental sulfur in the organic anti-shrinkage agent is 4000 μmol / g to 8000 μmol / g, it can be seen that the life performance is significantly improved by setting the contact angle to 40 ° or less.

Example 4
A lead-acid battery fully charged after chemical conversion was formed in the same manner as in Example 1 except that a condensate of naphthalene having a content of elemental sulfur of 6000 μmol / g with formaldehyde (a naphthalene-based organic preservative) was used as the organic preservative. A negative electrode plate having a void ratio of the negative electrode material of 0.22 cm ³ / g was produced, and a lead storage battery was assembled.

[Evaluation 4]
Regarding the lead storage battery prepared in Example 3 and the lead storage battery using the formaldehyde condensate of bisphenols (bisphenol-based organic shrinking agent) having a content of elemental sulfur of 6000 μmol / g prepared in Example 1, Evaluation 2, Similarly to 3, the number of IS life cycles and the 5-hour rate (0.2 CA) discharge duration were measured. The results are shown in Table 1.

  From Table 1, it can be understood that when the organic shrinkage agent is naphthalene-based, substantially the same results are obtained as when the organic shrinkage-proofing agent is bisphenol-based.

  The present invention is applicable to, for example, a liquid lead-acid battery, and is suitably used as a power source for automobiles, motorcycles, electric vehicles (forklifts, etc.), and the like.

  1: lead storage battery, 2: negative electrode plate, 3: positive electrode plate, 4s: separator, 4a: negative electrode side non-woven fabric mat, 4c: positive electrode side non-woven fabric mat, 5: positive electrode shelf, 6: negative electrode shelf, 7: positive electrode column, 8: Through connection body, 9: negative pole, 11: electrode plate group, 12: battery case, 13: partition, 14: cell chamber, 15: lid, 16: negative terminal, 17: positive terminal, 18: liquid plug

Claims (6)

A negative electrode plate, a positive electrode plate, a separator interposed between the negative electrode plate and the positive electrode plate, and an electrolyte solution,
The negative electrode plate includes a negative electrode current collector and a negative electrode material,
The negative electrode material includes an organic shrinking agent,
The lead acid battery in which the nonwoven fabric mat is interposing between the said negative electrode plate and the said separator, and between the said positive electrode plate and the said separator, respectively. The space ratio of the negative electrode material, 0.15 cm ³ / g or more and 0.22 cm ³ / g or less, a lead acid battery according to claim 1. The space ratio of the negative electrode material, 0.22 cm ³ / g or more and 0.27 cm ³ / g or less, a lead acid battery according to claim 1.   The lead acid battery according to any one of claims 1 to 3, wherein the content of elemental sulfur in the organic shrink-preventing agent is 4000 µmol / g or more and 8000 µmol / g or less.   The lead acid battery of any one of Claims 1-4 whose contact angle of the said electrolyte solution with respect to the said nonwoven fabric mat is 0 degree or more and 40 degrees or less.   The lead acid battery of Claim 5 whose contact angle of the said electrolyte solution with respect to the said nonwoven fabric mat is 25 degrees or less.