JP6766504B2 - Lead-acid battery - Google Patents

Description

The present invention relates to a lead storage battery.

Lead-acid batteries are used for various purposes such as in-vehicle use and industrial use. The lead-acid 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 (lead spongy or lead sulfate) whose capacity is developed by a redox reaction. In the negative electrode plate, the reduction reaction of lead sulfate proceeds during charging, but lead sulfate is difficult to be reduced to spongy lead. Therefore, sulfation in which lead sulfate crystals gradually grow progresses. Further, during charging, the sulfuric acid concentration of the electrolytic solution around the electrode plate becomes high, and the partially high-concentration sulfuric acid solution tends to settle in the lower part of the battery. Since these phenomena reduce the discharge performance and life performance of lead-acid batteries, various measures are being studied as follows.

Patent Document 1 teaches that a bisphenol condensate is contained in a negative electrode material as an organic shrinkage proofing agent.

Patent Document 2 proposes that the porosity of the negative electrode active material is 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 a negative electrode plate.

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

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

Although various improvement techniques have been tried as described above, it is becoming increasingly difficult to further improve the discharge performance of lead-acid batteries.

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, and the negative electrode plate includes a negative electrode current collector and a negative electrode. The negative electrode material includes an electrode material, the negative electrode material contains an organic shrinkage proofing agent, a non-woven mat is interposed between the positive electrode plate and the separator, and the void ratio of the negative electrode material is 0.22 cm. ^It relates to a lead storage battery which is ³ / g or more and 0.27 cm ³ / g or less.

According to the present invention, the discharge performance of the lead storage battery can be improved, and the low rate discharge capacity can be increased.

It is an exploded perspective view which cut out a part which shows the appearance and the internal structure of the lead storage battery which concerns on one Embodiment of this invention. It is a figure which shows the relationship between the content of the sulfur element in the organic shrinkage-proofing agent, and the amount of falling off of a positive electrode material. It is a figure which shows the relationship between the content of the sulfur element in the organic shrinkage-proofing 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 the presence or absence of a non-woven fabric mat, and the 5-hour rate discharge duration (0.2CA discharge duration). It is a figure which shows the relationship between the void ratio of the negative electrode electrode material, and the 5 hour rate discharge duration (0.2CA discharge duration). It is a figure which shows the relationship between the presence or absence of a non-woven fabric mat, the void ratio of a negative electrode material, and the 5-hour rate discharge duration (0.2CA discharge duration). It is a figure which shows the relationship between the content of the sulfur element in an organic shrink-proofing agent, and the 5-hour rate discharge duration (0.2CA discharge duration) when the contact angle of the electrolytic solution with respect to the non-woven fabric mat is changed. ..

The lead-acid 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, the negative electrode material contains an organic shrinkage proofing agent, and the void ratio of the negative electrode material is 0.22 cm ³ / g or more and 0.27 cm ³ / g. It is as follows. Further, a non-woven fabric mat is interposed between the positive electrode plate and the separator. It is preferable that the non-woven fabric mat is not integrated with the positive electrode plate and is arranged in contact with the positive electrode plate.
As an embodiment of the present invention, a liquid type (vent type) lead storage battery is more suitable than a control valve type (sealed type) lead storage battery.

With interposing a non-woven mat between the positive electrode plate and the separator, the void ratio of the negative electrode material 0.22 cm ³ / g or more, by the following 0.27 cm ³ / g, the low rate discharge performance of lead-acid battery improves. Above all, when the content of the sulfur element in the organic shrink-proofing agent is 4000 to 8000 μmol / g (more preferably 6000 to 8000 μmol / g), the discharge performance is remarkably improved. The negative electrode material having a void ratio of 0.22 to 0.27 cm ³ / g has a large contact area with the electrolytic solution, has a high utilization rate, and has a specific resistance of the negative electrode material due to the action of the organic shrinkage proofing agent. Is considered to be low. In addition, the presence of the non-woven fabric mat between the positive electrode plate and the separator makes the diffusion of sulfate ions around the electrode plate uniform, and discharge tends to occur uniformly regardless of the top and bottom of the electrode plate. It is thought that the utilization rate will improve.

The content of the sulfur element in the organic shrink-proofing agent is X μmol / g, which means that the content of the sulfur element contained in 1 g of the organic shrink-proofing agent is X μmol.

Void ratio of the negative electrode material is 0.22 cm ³ / g or more, when the 0.27 cm ³ / g or less, the density of the negative electrode material is roughly 3.2g / cm ³ ~2.5g / cm ³ order (i.e. low Density). At this time, the median value of the volume-based pore size distribution is preferably, for example, 0.1 μm to 10 μm.

In general, organic shrinkage proofing agents can be expected to improve the high-rate discharge performance of lead-acid batteries at low temperatures and the charge acceptance performance of negative electrode plates. However, it is becoming clear that some of the organic shrink-proofing agents added to the negative electrode plate tend to elute into the electrolytic solution 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 likely to fall off from the positive electrode current collector. Then, the loss of the positive electrode material tends to occur more easily as the content of the sulfur element in the organic shrink-proofing agent increases.

It is preferable that the non-woven fabric mat interposed between the positive electrode plate and the separator is not integrated with the positive electrode plate and is arranged in contact with the positive electrode plate. As a result, it is considered that the non-woven fabric mat also has an effect of remarkably suppressing the falling off of the positive electrode material. For example, even when the content of the sulfur element in the organic shrink-proofing agent is 4000 to 8000 μmol / g, the content of the sulfur element in the organic shrinkage-proofing agent is about 600 μmol / g, which is the same level as when the non-woven fabric mat is not used. It is possible to suppress the falling off of the positive electrode material. When a non-woven fabric mat is interposed between the positive electrode plate and the separator, contact between the positive electrode material and the gas is physically suppressed even if gas is generated. Therefore, it is considered that the positive electrode material is less likely to be affected by gas generation and is less likely to fall off. Further, it is considered that the non-woven fabric mat also has an effect of suppressing the precipitation of sulfate ions and suppressing the stratification of the electrolytic solution.

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

As a specific example of the organic shrink-proofing agent, a condensation product of a compound having a sulfur-containing group and having one or more, preferably two or more aromatic rings, made of formaldehyde 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 a general term for compounds having a bisphenol skeleton, a biphenyl skeleton and a naphthalene skeleton, respectively, and each may have a substituent. These may be contained alone in the organic shrink proofing agent, or may contain a plurality of kinds. As the bisphenol, bisphenol A, bisphenol S, bisphenol F and the like are preferable. Above all, since bisphenol S has a sulfonyl group (−SO ₂₋ ) in the bisphenol skeleton, it is easy to increase the content of sulfur element.

Condensates of bisphenols do not impair their performance at low temperatures even if they experience a temperature environment higher than room temperature, so they can be used for lead-acid batteries (such as liquid lead-acid batteries for automobiles) that are placed in a temperature environment higher than room temperature. Are suitable. The naphthalene sulfonic acid condensate is less likely to have a smaller polarization than the bisphenol condensate, and is therefore suitable for lead-acid batteries in which liquid-reducing properties are important.

The sulfur-containing group may be directly bonded to an aromatic ring of bisphenols, biphenyls, naphthalenes, etc., and may be bonded to the aromatic ring as an alkyl chain having a sulfur-containing group, for example. Further, 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.

Organic condensate of N, N'-(sulfonyldi-4,1-phenylene) bis (1,2,3,4-tetrahydro-6-methyl-2,4-dioxopyrimidine-5-sulfonamide) It may be used as a shrink-proofing agent.

The content of the organic shrink-proofing agent contained in the negative electrode electrode material does not significantly affect the action of the organic shrinkage-proofing agent within a general range. The content of the organic shrink-proofing agent contained in the negative electrode 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. It is preferably 0% by mass or less, more preferably 0.8% by mass or less, still more preferably 0.3% by mass or less. Here, the content of the organic shrinkage-proofing agent contained in the negative electrode material is the content in the negative electrode material collected by the method described later from a prefabricated lead-acid battery in a fully charged state.

From the viewpoint of reducing the specific resistance of the negative electrode material, increasing the utilization rate of the electrode material, and improving the low-rate discharge capacity, the content of the sulfur element in the organic shrink-proofing agent is preferably 2000 μmol / g or more, and 3000 μmol / g. It is more preferably g or more, further preferably 4000 μmol / g or more, and particularly preferably 6000 μmol / g or more.

It is difficult to make the content of sulfur elements in the organic shrink proofing agent excessively high. The content of the sulfur element in the organic shrink proofing agent may be 10,000 μmol / g or less, more preferably 9000 μmol / g or less, and further preferably 8000 μmol / g or less.

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described for each of the main constituent requirements, but the present invention is not limited to the following embodiments.
(Negative electrode plate)
The negative electrode plate of the lead storage battery includes a negative electrode current collector and a negative electrode material. The negative electrode material is held in 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 in the negative electrode current collector may be any of Pb-Sb-based alloys, Pb-Ca-based alloys, and Pb-Ca-Sn-based alloys. These leads or lead alloys 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 may have a plurality of lead alloy layers.

The negative electrode electrode material contains a negative electrode active material (lead or lead sulfate) whose capacity is developed by a redox reaction and the synthetic organic shrink-proofing agent described above in a predetermined content. The negative electrode material may further contain a carbonaceous material such as carbon black, barium sulfate, and the like, and may also contain other additives, if necessary.

The negative electrode active material in the charged state is spongy lead, but the unchemicald 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 prepare an unchemicald negative electrode plate, and then forming an unchemicald negative electrode plate. The negative electrode paste is prepared by adding water and sulfuric acid to lead powder, an organic shrink-proofing agent, and various additives and kneading them. At this time, it is preferable to ripen at a temperature higher than room temperature and high humidity.

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

(Positive electrode)
The positive electrode plate of a 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 in 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 a lead alloy sheet.
The clad type positive electrode has a plurality of porous tubes, a core metal inserted in each tube, a positive electrode material filled in the tube into which the core metal is inserted, and a collective punishment for connecting the plurality of tubes. Equipped.

As the lead alloy used for the positive electrode current collector, Pb-Ca-based alloys, Pb-Ca-Sn-based alloys and the like are preferable 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-based alloy for the core metal.

The positive electrode material contains a positive electrode active material (lead oxide or lead sulfate) whose capacity is developed by a redox reaction. The positive electrode material may contain additives such as tin sulfate and lead tan, if necessary, in addition to the positive electrode active material.

The unchemical 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 is prepared by kneading lead powder, additives, water, and sulfuric acid. Then, an unchemical positive electrode plate is formed. The clad-type 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 connecting a plurality of tubes in a collective punishment.

(Electrolytic solution)
The electrolytic solution is an aqueous solution containing sulfuric acid, and may be gelled if necessary. The degree of gelation is not particularly limited. A gel-like electrolyte solution from a sol having fluidity may be used, or a gel-state electrolyte solution having no fluidity may be used. The specific gravity of the electrolytic solution in the fully charged lead-acid battery at 20 ° C. is, for example, 1.10 to 1.35 g / cm ³ , and preferably 1.20 to 1.35 g / cm ³ .

(Non-woven mat)
The non-woven fabric mat is a sheet in which a fiber material insoluble in an electrolytic solution is entwined without weaving. As the fiber material, glass fiber, polymer fiber, pulp fiber and the like can be used. Among the polymer fibers, polyolefin fibers are preferable. The non-woven fabric mat may contain components other than the fiber material, and may contain, 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 and the like can be used. However, from the viewpoint of uniformly diffusing the abundant electrolytic solution in the pores of the non-woven fabric mat, 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.

The average fiber diameter of the fiber material constituting the non-woven fabric mat is, for example, 0.1 μm to 25 μm. The average particle size of the inorganic powder constituting the non-woven fabric mat is, for example, 1 μm to 100 nm. These average values can be obtained from an enlarged photograph of 10 or more fibers or 10 or more particles arbitrarily selected and selected fibers. The particle diameter of the particles is the diameter of a corresponding circle having the same area as the projected area of the particles that can be confirmed in the enlarged photograph.

The contact angle θm of the electrolytic solution with respect to the non-woven fabric mat is preferably 0 ° to 40 °, more preferably less than 30 °, and even 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 non-woven fabric mat is improved, and it becomes easier to improve the life performance and the low rate discharge performance. Above all, when the content of the sulfur element in the organic shrink-proofing 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 Discharge performance is significantly improved.

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

The thickness of the non-woven 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 the like, and may be selected from, for example, the range of 0.1 mm to 2 mm.

(Separator)
A microporous membrane is used as the separator. The microporous membrane is a sheet mainly composed of materials other than fiber materials. For example, a composition containing polymer powder, silica powder and oil is extruded into a sheet, and then the oil is extracted to form pores. can get. The polymer component constituting the separator is preferably one having acid resistance, and preferably a polyolefin such as polyethylene or polypropylene. The microporous membrane may contain a small amount of fiber material, but 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-acid battery, the thickness of the positive electrode plate and the negative electrode plate, and the like, and may be selected from, for example, a thickness of 0.4 to 1.3 m. When the separator has irregularities on the surface, the thickness of the portion having the convex portions may be within the above 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 thereof, the total thickness of the base and the ribs may be within the above range. Further, two or more layers of separators may be laminated and used, or two or more layers of separators may be adhered and integrated.

Next, the analysis method of each physical property will be described.
(1) Void ratio of negative electrode material The electrolytic solution in the negative electrode plate is removed by fully charging the battery after chemical conversion, disassembling the battery, and washing and drying the obtained negative electrode plate with water. Next, the negative electrode material is separated from the negative electrode plate to obtain an unground measurement sample. The measurement sample is degassed under reduced pressure using a vacuum pump, 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. The volume of water that has entered the void inside the measurement sample can be determined from the difference in mass of the measurement sample before and after immersion and the value of the true density of water. 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 supplementary charging conditions for making the lead-acid battery fully charged are as follows.
In the case of a liquid battery, constant current charging is performed at 25 ° C. in a water tank at 0.2 CA until it reaches 2.5 V / cell, and then constant current charging is performed at 0.2 CA for 2 hours.
In the case of a VRLA battery (control valve type lead-acid battery), 0.2CA, 2.23V / cell constant current constant voltage charging was performed at 25 ° C. in the air tank, and the charging current during constant voltage charging became 1 mCA or less. Charging ends at that point.
In this specification, 1CA is a current value for discharging the nominal capacity of the battery in 1 hour. For example, in the case of a battery having a nominal capacity of 30Ah, 1CA is 30A and 1mCA is 30mA.

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 then disassembled, and the obtained negative electrode plate is washed with water and dried to remove the electrolytic solution in the negative electrode plate. Next, the negative electrode material is separated from the negative electrode plate to obtain an unground measurement sample. After the sample is placed in the measuring container and evacuated, the bulk volume of the negative electrode material is measured by filling mercury at a pressure of 0.5 to 0.55 psia, and the mass of the measurement sample is divided by the bulk volume. , Obtain the bulk density of the negative electrode material. The volume obtained by subtracting the mercury injection volume from the volume of the measuring container is defined as the bulk volume.

(2) Contact angle of electrolytic solution with respect to the non-woven fabric mat In the same manner as described above, the non-woven fabric mat is taken out from the lead storage battery fully charged after chemical conversion, washed, dried, and a sample piece of the non-woven fabric 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. was dropped onto the horizontal plane of the collected sample piece as a standard electrolytic solution, and the image of the formed droplets 2 seconds later was analyzed. Then, the contact angle is measured by the θ / 2 method.

(3) Analysis of organic shrink-proofing agent First, the lead-acid battery fully charged after chemical conversion is disassembled, the negative electrode plate is taken out, sulfuric acid is removed by washing with water, and the battery is dried. Next, the 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) Qualitativeity of Organic Shrink-Proof Agent in Negative Electrode Material The initial sample is immersed in a 1 mol / L NaOH aqueous solution to extract the organic shrink-proof agent. Next, the insoluble component is removed by filtration from the extracted aqueous NaOH solution containing the organic shrink-proofing agent, the obtained filtrate is desalted, concentrated, and dried. Desalination may be carried out by placing the filtrate in a dialysis tube and immersing it in distilled water. As a result, a powder sample of the organic shrink proofing agent can be obtained.

Obtained from the infrared spectroscopic spectrum measured using the powder sample of the organic shrink-proofing agent thus obtained, and the ultraviolet-visible absorption spectrum and NMR spectrum measured by an ultraviolet-visible absorbance meter by dissolving the powder sample in an appropriate solvent. The information is used in combination to identify the species of organic shrink-proofing agent.

(3-2) Quantification of the content of the organic shrink-proofing agent in the negative electrode material In the same manner as in (3-1) above, after obtaining a filtrate of the NaOH aqueous solution containing the organic shrinkage-proofing agent, the ultraviolet-visible absorption spectrum of the filtrate is measured. To do. The content of the organic shrink-proofing agent in the negative electrode electrode material can be quantified using the spectral intensity and the calibration curve prepared in advance.
When the battery is obtained and the content of the organic shrink-proof agent is measured, if the same organic shrink-proof agent cannot be used on the calibration curve because the structural formula of the organic shrink-proof agent cannot be specified exactly, the negative electrode of the battery is used. By creating a calibration curve using a separately available organic shrink-proofing agent that has a similar shape to the organic shrink-proofing agent extracted from UV-visible absorption spectrum, infrared spectroscopic spectrum, NMR spectrum, etc., UV-visible The content of the organic shrink-proofing agent is measured using the absorption spectrum.

(3-3) Sulfur element content in organic shrink-proofing agent In the same manner as in (3-1) above, after obtaining a powder sample of organic shrink-proofing agent, in 0.1 g of organic shrinkage-proofing agent by the oxygen combustion flask method. Converts the sulfur element of 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 can be obtained. Next, the content (C1) of the sulfur element in 0.1 g of the organic shrink-proofing agent is determined by titrating the eluate with barium perchlorate using thorin as an indicator. Next, C1 is multiplied by 10 to calculate the content of sulfur element (μmol / g) in the organic shrink-proofing agent per 1 g.

FIG. 1 shows the appearance of an example of a lead storage battery according to an embodiment of the present invention.
The lead-acid battery 1 includes an electric tank 12 that houses a electrode plate group 11 and an electrolytic solution (not shown). The inside of the electric tank 12 is partitioned into a plurality of cell chambers 14 by a partition wall 13. 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 spout 18 for each cell chamber. At the time of rehydration, the liquid spout 18 is removed and the rehydration liquid is replenished. The liquid spout 18 may have a function of discharging the gas generated in the cell chamber 14 to the outside of the battery.

The electrode plate group 11 is formed by laminating a plurality of negative electrode plates 2 and positive electrode plates 3 via a separator 4s, respectively. The positive electrode plate 3 is sandwiched between a pair of non-woven fabric mats 4c. The non-woven fabric mat 4c is attached to both sides of the positive electrode plate 3. Here, the bag-shaped separator 4 accommodating the negative electrode plate 2 is shown, but the form of the separator is not particularly limited. In the cell chamber 14 located at one end of the battery case 12, a negative electrode shelf 6 for connecting a plurality of negative electrode plates 2 in parallel is connected to a through connecting body 8, and a positive electrode shelf 5 for connecting a plurality of positive electrode plates 3 in parallel is provided. It is connected to the positive electrode column 7. The positive electrode column 7 is connected to the positive electrode terminal 17 outside the lid 15. In the cell chamber 14 located at the other end of the battery case 12, the negative electrode column 9 is connected to the negative electrode shelf 6, and the through connector 8 is connected to the positive electrode shelf 5. The negative electrode column 9 is connected to the negative electrode terminal 16 outside the lid 15. Each through-connecting body 8 passes through a through-hole provided in the partition wall 13 and connects the electrode plates 11 of the adjacent cell chambers 14 in series.

Hereinafter, the present invention will be described in more detail 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 A negative electrode paste was obtained by mixing lead powder as a raw material, barium sulfate, carbon black, and an organic shrink proofing agent with an appropriate amount of an aqueous sulfuric acid solution. The negative electrode paste was filled in the mesh portion of the expanded lattice made of Pb-Ca—Sn alloy and aged and dried to obtain an unchemicald negative electrode plate.

The organic shrinkage proofing agent was blended in the negative electrode paste so that the content of the organic shrinkage proofing agent in the negative electrode electrode material of the lead storage battery fully charged after chemical conversion was 0.1% by mass. In addition, the amount of water and sulfuric acid to be added to the negative electrode paste should be 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 of volume-based pore size distribution 2 μm). Controlled.

As the organic shrinkage proofing agent, a condensate of lignin or a bisphenol having a sulfonic acid group introduced by formaldehyde was used. Here, the amount of the sulfonic acid group to be introduced was controlled so that the content of the sulfur element in the organic shrinkage proofing agent was 2000 to 8000 μmol / g. The sulfur element content of lignin was 600 μmol / g.

(2) Preparation of Positive Electrode Plate The lead powder as a raw material was mixed with an aqueous sulfuric acid 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 and aged and dried to obtain an unchemicald positive electrode plate.

(3) Non-woven fabric mat As the non-woven fabric mat, a sheet (thickness 0.5 mm) obtained by mixing glass fiber (average fiber diameter 0.5 μm) and silica powder (average particle diameter 5 nm) was used. The contact angle of the electrolytic solution with respect to the non-woven fabric mat was controlled to 20 ° by the hydrophilic treatment.

(4) Separator The separator is a microporous membrane (having ribs) in which a composition containing polyethylene powder, silica powder and oil is extruded into a sheet having a plurality of ribs, and then the oil is extracted to form pores. The thickness of the portion (0.5 mm) was used. Here, the microporous membrane was folded in half and the two sides intersecting the creases were welded to prepare a bag-shaped separator.

(5) Preparation of lead-acid battery The negative electrode plate was housed in a bag-shaped separator. On the other hand, non-woven fabric mats were attached to both sides of the positive electrode plate. A group of electrode plates was formed by five negative electrode plates and four positive electrode plates.

The electrode plates were housed in a polypropylene electric tank together with the electrolytic solution, and chemical conversion was performed in the electric tank. In this way, a plurality of types of liquid lead-acid batteries for automobiles having different sulfur element contents in the organic shrinkage proofing agent were assembled. The output of the lead-acid battery is 12V, and the rated 5-hour rate capacity is 25Ah. The specific gravity of the electrolytic solution after chemical conversion was 1.28 g / cm ³ .

<< Comparative Example 1 >>
Similar to Example 1, a plurality of types of lead-acid batteries having different sulfur element contents in the organic shrink-proofing agent were assembled, except that the non-woven fabric mats were not attached to both sides of the positive electrode plate.

<< Comparative Example 2 >>
Similar to Example 1, a plurality of types of lead-acid batteries having different sulfur element contents in the organic shrink-proofing agent, except that the non-woven fabric mats are attached to both sides of the negative electrode plate and the non-woven fabric mats are not attached to both sides of the positive electrode plate. Assembled.

[Evaluation 1]
The lead-acid batteries of Example 1 and Comparative Examples 1 and 2 were subjected to an IS life test under the following conditions.
<Cycle conditions>
The idling stop (IS) life test specified in SBA S 0101: 2006 was performed. That is, after discharging from a fully charged state at 45 A for 59 seconds, further discharging at 300 A for 1 second, a charge / discharge cycle of constant voltage charging at 14 V for 60 seconds with an upper limit current of 100 A was repeated. In addition, the lead-acid battery was allowed to rest for 40 to 48 hours every 3600 cycles. The test was terminated when the voltage after 1 second of 300 A discharge became less than 7.20 V.

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

Further, 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 accumulated was measured. First, the collected negative electrode material was washed with water, dried, and then pulverized. Next, the content of sulfur element in the pulverized negative electrode material (crushed sample) was measured using an elemental sulfur analyzer (for example, S-200 type manufactured by LECO). Next, the content of sulfur element in lead sulfate accumulated in the negative electrode material was determined according to the following formula.

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

Next, the content of the sulfur element in lead sulfate was converted into the amount of lead sulfate, and the lead sulfate concentration (mass%) per unit mass of the crushed sample was obtained and used as the lead sulfate accumulation amount. It can be said that the greater the amount of lead sulfate accumulated, the more the sulfation and the stratification of the electrolytic solution progress.

Table 1 and FIG. 2 show the relationship between the content of the sulfur element in the organic shrink-proofing agent and the amount of the positive electrode material falling off from the positive electrode plate with respect to Example 1 and Comparative Examples 1 and 2. Tables 2 and 3 show the relationship between the content of the sulfur element in the organic shrinkage proofing 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 sulfur element in the organic shrink-proofing agent, the larger the amount of the positive electrode material that falls off. However, in Example 1 in which the non-woven fabric mats are attached to both sides of the positive electrode plate, the deterioration of the positive electrode plate is remarkably suppressed.

FIG. 3 shows that the larger the content of sulfur element in the organic shrink proofing agent, the smaller the amount of lead sulfate accumulated. This suggests that the higher the sulfur element content, the more the stratification of the electrolytic solution is suppressed.

<< 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 Multiple types of lead-acid batteries with different element contents were assembled. The contact angle of the electrolytic solution with respect to the non-woven fabric mat was unified to 20 °.

<< Comparative Example 3 >>
Similar to Comparative Example 1, a plurality of types of lead-acid batteries having different sulfur element contents in the organic shrinkage-proofing agent, except that the void ratio of the negative electrode material of the lead-acid battery fully charged after chemical conversion was 0.24 cm ³ / g. Assembled.

<< Comparative Example 4 >>
Similar to Comparative Example 2, a plurality of types of lead-acid batteries having different sulfur element contents in the organic shrinkage-proofing agent, except that the void ratio of the negative electrode material of the lead-acid battery fully charged after chemical conversion was 0.24 cm ³ / g. Assembled.

[Evaluation 2]
With respect to the lead-acid batteries produced in Example 2 and Comparative Examples 3 to 4, the 5-hour rate (0.2CA) discharge duration was measured under the following conditions.
A 5-hour rate capacity test specified in JIS D5301 (SBA S 0101: 2006) was performed. That is, after confirming that the electrolyte temperature in the central cell chamber is 25 ° C ± 2 ° C, use a 5-hour rate current (0.2CA) until the terminal voltage drops to 10.50V ± 0.05V. The discharge was performed, the discharge duration (t) was recorded, and the capacity was determined.

Tables 3 and 4 show the relationship between the presence or absence of the non-woven fabric mat and the 0.2CA discharge duration when the void ratio of the negative electrode material is 0.24 cm ³ / g. Table 4 and FIG. 5 show the relationship between the void ratio of the negative electrode material and the 0.2CA discharge duration.

FIG. 4 shows that the discharge performance of the lead storage battery tends to be improved when the non-woven fabric mats are attached to both sides of the positive electrode plate.

5, 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 discharge performance is shown more prominently. Specifically, in the graph in which the content of the sulfur element in the organic shrink proofing agent is 4000 μmol / g to 8000 μmol / g, there is a change point not seen in the graph of 600 μmol / g to 2000 μmol / g. The increase in 0.2CA discharge duration accompanied by such a change point is a tendency peculiar to the case where the content of the sulfur element in the organic shrinkage proofing agent is 4000 μmol / g to 8000 μmol / g.

<< Comparative Example 5 >>
The content of elemental sulfur in the organic expander agent in the 6000μmol / g, was a void ratio of negative electrode material of lead-acid battery fully charged to after conversion varied between 0.14cm ³ /g~0.30cm ³ / g Except for the above, the lead storage battery was assembled in the same manner as in Comparative Example 1.

<< Comparative Example 6 >>
The content of elemental sulfur in the organic expander agent in the 6000μmol / g, was a void ratio of negative electrode material of lead-acid battery fully charged to after conversion varied between 0.14cm ³ /g~0.30cm ³ / g Except for this, a lead storage battery was assembled in the same manner as in Comparative Example 2.

Tables 5 and 6 show the void ratio of the negative electrode material and the 0.2CA discharge duration when the content of the sulfur element in the organic shrink-proofing agent of Comparative Examples 5 and 6 and Example 2 was 6000 μmol / g. Show the relationship. In FIG. 6, a non-woven fabric mat is interposed between the positive electrode plate and the separator, and the void ratio of the negative electrode material is 0.22 to 0.27 cm ³ / g, so that the lead-acid battery has a 5-hour discharge duration. Is shown to be significantly improved.

Sulfur element content in organic shrink proofing agent: 6000 μmol / g

<< Example 3 >>
Similar to Example 1, the sulfur element in the organic shrink-proofing agent was changed, except that the contact angle of the electrolytic solution with respect to the non-woven fabric mat was changed in the range of 10 ° to 80 ° by changing the surface treatment conditions of the non-woven fabric mat. A plurality of types of lead-acid batteries having different contents were assembled and evaluated in the same manner as in Evaluation 2 above. However, the void ratio of the negative electrode material was unified to 0.22 cm ³ / g.

Table 6 and FIG. 7 show the relationship between the content of the sulfur element in the organic shrink-proofing agent and the 0.2CA discharge duration when the contact angle of the electrolytic solution with respect to the non-woven fabric mat was changed with respect to Example 3. FIG. 7 shows that it is advantageous to set the contact angle of the electrolytic solution with respect to the non-woven fabric mat to 40 ° or less (further, less than 30 °) from the viewpoint of improving the discharge performance of the lead storage battery. In particular, when the content of the sulfur element in the organic shrink-proofing agent is 4000 μmol / g to 8000 μmol / g, it can be seen that the discharge performance is remarkably improved by setting the contact angle to 40 ° or less.

<< Example 4 >>
As the organic shrinkage-proofing agent, the voids of the ready-made negative electrode material are the same as in Example 1 except that a condensate of naphthalenes having a sulfur element content of 6000 μmol / g with formaldehyde (naphthalene-based organic shrinkage-proofing agent) is used. A negative electrode plate having a ratio of 0.22 cm ³ / g was prepared, and a lead storage battery was assembled.

[Evaluation 3]
The lead-acid battery prepared in Example 3 and the lead-acid battery prepared in Example 1 using a formaldehyde-based condensate of bisphenols having a sulfur element content of 6000 μmol / g (bisphenol-based organic shrink-proofing agent) were evaluated as Evaluation 2. Similarly, the 5-hour rate (0.2CA) discharge duration was measured. The results are shown in Table 7.

From Table 1, it can be understood that substantially the same results can be obtained when the organic shrink-proofing agent is naphthalene-based as well as when the organic shrink-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-acid battery, 2: Negative electrode plate, 3: Positive electrode plate, 4s: Separator, 4c: Non-woven mat, 5: Positive electrode shelf, 6: Negative electrode shelf, 7: Positive electrode column, 8: Through connector, 9: Negative electrode column, 11: Electrode plate group, 12: Electric tank, 13: Partition, 14: Cell chamber, 15: Lid, 16: Negative terminal, 17: Positive terminal, 18: Liquid spout

Claims (4)

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 are provided.
It is a liquid type
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 and contains
A non-woven fabric mat is interposed between the positive electrode plate and the separator.
The space ratio of the negative electrode material, 0.22 cm ³ / g or more, or less 0.27 cm ³ / g, lead-acid batteries. 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 are provided.
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 and contains
A non-woven fabric mat is interposed between the positive electrode plate and the separator.
Void ratio of the negative electrode material, 0.22 cm ³ / g or more, or less 0.27 cm ³ / g,
A lead-acid battery in which the content of sulfur elements in the organic shrink-proofing agent is 4000 μmol / g or more and 8000 μmol / g or less. The lead-acid battery according to claim 1 or 2, wherein the contact angle of the electrolytic solution with respect to the non-woven fabric mat is 0 ° or more and 40 ° or less. The lead-acid battery according to claim 3, wherein the contact angle of the electrolytic solution with respect to the non-woven fabric mat is 25 ° or less.