JP2017224483A - Lead storage battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead storage battery which has a good discharge performance and which has a satisfying life property even if it is operated in such a standby use that it is discharged with a discharge depth of about 30% at intervals of several months.SOLUTION: A lead storage battery according to the present invention is operated in a state of charge of 95-100% to 100% of the state of full charge. The lead storage battery comprises: a positive electrode plate; a negative electrode plate; a glass nonwoven fabric provided between the positive electrode plate and the negative electrode plate; and an electrolyte solution including aluminum ions. The glass nonwoven fabric includes 55-70 pts.mass of glass fibers of 1.0 μm or smaller in fiber diameter to a total mass of 100 pts.mass of glass fibers constituting the glass nonwoven fabric.SELECTED DRAWING: None

Description

  The present invention relates to a lead storage battery operated for standby use.

  Lead acid batteries are secondary batteries excellent in cost, safety, and reliability, and are used in various applications. One example of the operation of a lead storage battery is an emergency power supply for a DC power supply of a telephone switch for general lines. In this operation example, a type of battery called a control valve type lead-acid battery is used, and a charging method such as trickle charging or float charging that always maintains a charged state is employed. In these charging methods, since the charged state is maintained for the purpose of compensating for the storage battery capacity loss due to self-discharge, the battery deterioration proceeds mainly due to corrosion of the electrode current collector. Conventionally, by using a Pb—Sn—Ca-based alloy as a positive electrode current collector, both excellent corrosion resistance and high strength have been achieved.

  In recent years, a control valve type lead battery operated in a standby use may be discharged at a depth of discharge (DOD) of about 30% every several months in order to ensure the soundness of power supply equipment. It has been confirmed that when such a discharge is performed, a capacity reduction not caused by corrosion of the positive electrode current collector can occur. This decrease in capacity occurs because sulfate, which is a nonconductor, is selectively generated at the interface between the positive electrode current collector and the positive electrode active material.

  The Pb—Sn—Ca-based alloy described above is excellent in corrosion resistance and therefore has poor adhesion with the positive electrode active material. For this reason, a process called aging is performed in the process of manufacturing the positive electrode plate. In general, aging corrodes the positive electrode current collector in an atmosphere in which the temperature and humidity are controlled, thereby bringing the positive electrode active material and the positive electrode current collector into close contact with each other. In Patent Document 1, aging is performed under predetermined conditions to generate tetrabasic lead sulfate in the unactivated active material, so that the active material expands through the aging step and the chemical conversion step, and thus, the paste type electrode It is disclosed that the electrode plate itself has a state like that when a strengthening pressure is applied, which contributes to improvement of cycle life performance (see paragraph [0028] of Patent Document 1).

JP 2000-260426 A

  The invention described in Patent Document 1 is effective even in the case of an active material having a high specific surface area of the positive electrode active material, and is also effective in standby use in which discharge is performed at a discharge depth of about 30% every several months. However, a higher level of performance is required for standby use batteries than ever before. Moreover, since the specific surface area of the active material derived from tetrabasic lead sulfate (after chemical conversion) is likely to be lower than that of acid-based lead sulfate, the invention described in Patent Document 1 is likely to have insufficient discharge performance. There was room for improvement.

  An object of the present invention is to provide a lead-acid battery having good discharge performance and having good life characteristics even when operated for standby use in which discharge is performed at a discharge depth of about 30% every several months.

  The lead storage battery according to the present invention is operated in a state of charge (SOC) of 95 to 100% assuming that the fully charged state is 100%, and includes a positive electrode plate, a negative electrode plate, a positive electrode plate, A glass nonwoven fabric provided between the negative electrode plate and an electrolyte containing aluminum ions is provided, and the glass nonwoven fabric contains glass fibers of 1.0 μm or less. According to the lead storage battery having this configuration, both the discharge performance and the life characteristic can be achieved at a sufficiently high level.

  The said glass nonwoven fabric contains 55-70 mass parts of glass fibers with a fiber diameter of 1.0 micrometer or less with respect to 100 mass parts of total mass of the glass fiber which comprises the said glass nonwoven fabric. By adopting such a configuration, the above-described effect can be further enhanced and ensured. From the same viewpoint, the aluminum ion concentration of the electrolytic solution is preferably 0.002 to 0.2 mol / L.

  ADVANTAGE OF THE INVENTION According to this invention, while having favorable discharge performance, even if it is operated by the standby use which discharges about 30% of discharge depth every several months, the lead storage battery which has a favorable lifetime characteristic is provided.

It is a perspective view showing one embodiment of a lead acid battery concerning the present invention.

  Hereinafter, embodiments of the present invention will be described. The present invention is not limited to the following embodiments. The materials exemplified below may be used alone or in combination of two or more unless otherwise specified. The content of each component in the composition means the total amount of the plurality of substances present in the composition unless there is a specific notice when there are a plurality of substances corresponding to each component in the composition. The numerical range indicated by using “to” indicates a range including the numerical values described before and after “to” as the minimum value and the maximum value, respectively. In the numerical ranges described stepwise in the present specification, the upper limit value or lower limit value of a numerical range of a certain step may be replaced with the upper limit value or lower limit value of the numerical range of another step. In the numerical range described in this specification, the upper limit value or the lower limit value of the numerical range may be replaced with the values shown in the examples.

<Lead battery>
A lead storage battery 1 shown in FIG. 1 includes a plurality of positive plates 2, a plurality of negative plates 3, a plurality of separators 4 (glass nonwoven fabric) provided between the positive plates 2 and the negative plates 3, and a battery case 5. , And a lid 6, and an electrode group in which the positive electrode plate 2, the separator 4, and the negative electrode plate 3 are alternately stacked is accommodated in the battery case 5. As for the some positive electrode plate 2, each ear | edge part 2a is electrically connected through the strap 2b. As for the some negative electrode plate 3, each ear | edge part 3a is electrically connected through the strap 3b. After the electrode plate group is accommodated in the battery case 5 and closed with the lid body 6, the lead storage battery 1 is manufactured by injecting a predetermined amount of electrolyte and performing battery case formation.

  The lead storage battery 1 is operated in a state of charge (SOC) of 95 to 100% (preferably 98 to 100%), assuming that the fully charged state is 100%. When lead acid battery 1 is a control valve type lead acid battery, a control valve for discharging excess gas, which has not been absorbed by the gas absorption reaction of the negative electrode, out of battery case 5 out of the oxygen gas generated at the positive electrode during charging 7 is further provided with the lead storage battery 1. The control valve type lead storage battery is used as an uninterruptible power supply, an emergency power supply, or the like. The control valve type lead-acid battery has the advantage that there is no flowing free electrolyte inside the battery and the electrolyte does not spill even when the battery is placed sideways. In addition, even if water electrolysis occurs during charging, it suppresses the generation of hydrogen gas, and the generated oxygen gas also has the action of reducing it back to the original water by a chemical reaction on the negative electrode plate surface. There is also an advantage that moisture is not easily lost, and liquid amount inspection and water replenishment are unnecessary.

  When the lead storage battery 1 is used as an uninterruptible power supply or an emergency power supply, it is preferable that the battery is fully charged in the standby state. However, if the battery is stored for a long time in a fully charged state, the amount of electricity stored during use is reduced by self-discharge or the like, so that the rated performance may not be exhibited or used. In order to prevent this, trickle charging to compensate for self-discharge may be performed. When trickle charging is performed, the state of charge of the control valve type lead-acid battery may be 95 to 100%, but is preferably 98 to 100% from the viewpoint of life performance. Trickle charging is preferably performed at a constant voltage by applying a voltage slightly higher than the nominal voltage to the electrodes of the control valve type lead-acid battery. Trickle charging naturally reduces the charging current when it approaches the fully charged state, and has the effect of preventing overcharging. The battery voltage can be prevented from being shortened by an excessive current by appropriately setting the charging voltage to prevent overcharging or by providing a current limiting circuit.

  The lead storage battery 1 is operated for standby use, and discharge at a discharge depth of about 30% may be performed every few months from the viewpoint of battery life determination.

  The battery case 5 may be divided into a plurality of cell chambers. In this case, electrode plate groups are accommodated in each cell chamber, and straps having opposite polarities to the electrode plate groups accommodated in the adjacent cell chambers are mutually connected. By connecting to, a lead storage battery having a predetermined rated voltage and rated capacity is configured. On the other hand, in the case of a single cell battery case, a battery having a predetermined voltage or capacity can be configured by connecting terminals of a plurality of lead storage batteries in parallel or in series using a conductive plate.

(Separator)
The separator 4 is a glass nonwoven fabric (a mat-like separator made of glass fibers). The separator 4 is provided between the positive electrode plate 2 and the negative electrode plate 3, and plays a role of holding the sulfuric acid electrolyte necessary for charging and discharging and isolating both electrodes. The glass fiber which comprises a glass nonwoven fabric contains 55-70 mass parts of glass fibers with a fiber diameter of 1.0 micrometer or less with respect to 100 mass parts of the total mass of the glass fiber which comprises the said glass nonwoven fabric. This numerical range may be 57 to 69 parts by mass, or 59 to 67 parts by mass. When the content of the glass fiber having a fiber diameter of 1.0 μm or less is 55% by mass or more, both strength and liquid retaining property sufficient as a glass nonwoven fabric tend to be obtained. In addition, all of the liquid retention and the cycle characteristics can be made sufficiently high in a balanced manner. The fiber diameter of the glass fiber can be determined, for example, by direct observation using a dynamic image analysis method, a laser scanning method (for example, conforming to JIS L1081), a scanning electron microscope, or the like. Specifically, these methods may be used to observe about 400 fibers and obtain the fiber diameter ratio.

  Since the glass fiber uses dilute sulfuric acid for the electrolytic solution, those having acid resistance such as alkali glass, ECR glass, Advantech glass and the like are preferable.

The basis weight of the glass fiber in the separator 4 is that the decrease in drainage at the time of manufacture is suppressed, so that the concentration distribution of the material is suppressed, so that the internal structure of the separator may become non-uniform. From the viewpoint of being suppressed, the pressure is preferably 0.5 g / cm ³ or less at 20 kPa pressurization, more preferably 0.3 g / cm ³ or less at 20 kPa pressurization, and 0. More preferably, it is 2 g / cm ³ or less. The basis weight of the glass fiber in the separator 4 is 0.1 g / cm ³ or more at the time of 20 kPa pressurization from the viewpoint of easily suppressing a short circuit by suppressing an excessive decrease in the thickness of the separator 4. More preferably, it is 0.15 g / cm ³ or more at a pressure of 20 kPa, and more preferably 0.17 g / cm ³ or more at a pressure of 20 kPa.

The density of the separator 4 is 0.10 to 0.20 g / cm ³ at a pressure of 20 kPa from the viewpoint of further excellent battery characteristics (output characteristics, battery capacity, etc.) and easy drying during production. Preferably, it is 0.11 to 0.20 g / cm ³ , more preferably 0.12 to 0.20 g / cm ³ . The content of the glass fiber in the separator 4 is preferably 70% by mass or more, more preferably 80 to 99% by mass, and more preferably 90 to 99% by mass with respect to the total amount of the separator, from the viewpoint of excellent balance between water absorption and mechanical strength. Is more preferable. In addition, as components other than the glass fiber in the separator 4, resin fiber, pulp, a flocculant, a binder, etc. are mentioned.

(Electrolyte)
The electrolyte solution of the lead storage battery 1 contains aluminum ions. The aluminum ion concentration of the electrolytic solution is preferably 0.002 to 0.2 mol / L, based on the total amount of the electrolytic solution, from the viewpoint of further improving charge acceptance and cycle characteristics, and 0.003 to 0.1 mol / L. Is more preferable, and 0.005-0.08 mol / L is still more preferable. The concentration of aluminum ions in the electrolytic solution can also be measured by, for example, ICP emission spectroscopy (high frequency inductively coupled plasma emission spectroscopy). In addition, electrolyte solution is contained not only in the separator 4 which consists of glass nonwoven fabrics but in a positive electrode plate and a negative electrode plate.

<Manufacturing method of separator>
There is no restriction | limiting in particular in the manufacturing method of the glass nonwoven fabric which makes the separator 4, For example, wet papermaking, dry papermaking, etc. are mentioned. In the present embodiment, among these, it is preferable to employ a papermaking method based on a wet method (wet papermaking). This production method includes a step of preparing a slurry prepared by mixing glass fiber and, if necessary, a resin or the like with water, a step of papermaking the slurry to prepare a papermaking product, and a papermaking product using a pressure machine In the thickness direction, and a manufacturing method through a step of heat-treating the compression body at a temperature equal to or higher than the softening point of the resin as necessary.

(Process for preparing slurry)
In this step, a slurry is prepared by dispersing glass fiber and, if necessary, resin, pulp and the like in a predetermined dispersion medium. The slurry can be prepared using, for example, a mixer, a ball mill, a pulper, or the like. Note that water is generally used as the dispersion medium. What is necessary is just to adjust content of each raw material component in a slurry so that content of each raw material component in the separator obtained may become the range mentioned above. However, from the viewpoint of ensuring good papermaking properties, it is preferable that the raw material component in the slurry is 100% and the glass fiber is 70 to 99% by mass. This is because if the amount is less than 70% by mass, a sufficient electrolyte solution cannot be retained for charging and discharging.

  The slurry may contain polymer particles as organic fibers or a binder as necessary. Organic fibers and polymer particles may be used alone or in admixture of two or more. Organic fibers and polymer particles include those sulfonated. By including these, there exists an effect that the mechanical strength of a glass nonwoven fabric becomes high.

  The slurry may contain a surfactant. When the slurry contains the surfactant, the raw material components are easily dispersed when the separator is manufactured. The surfactant may be decomposed in a subsequent heat treatment. As the surfactant, any of a silane coupling agent, a cationic surfactant, an anionic surfactant, and a nonionic surfactant may be used. The content of the surfactant is preferably 0.01 to 5% by mass with 100% of the raw material components in the slurry. If the amount is less than 0.01% by mass, a sufficient effect cannot be obtained. If the amount is more than 5% by mass, the control valve type lead-acid battery is eluted into the electrolytic solution, thereby promoting battery deterioration.

  The slurry may contain a flocculant. The yield of the separator manufactured by including a flocculant can be improved. The flocculant may be either a cationic polymer flocculant or an anionic polymer flocculant, and both may be used together. The content of the flocculant is preferably 0.001 to 0.5 mass% with the raw material component in the slurry as 100%. When the amount is less than 0.001% by mass, a sufficient effect cannot be obtained, and when the amount is more than 0.5% by mass, the control valve type lead-acid battery is eluted into the electrolyte solution to promote battery deterioration.

(Process from making paper making to compression)
In these processes, the slurry is paper-made using a general paper machine to produce a paper-making body, and then the paper-making body is further compressed in the thickness direction using a pressure machine. In order to obtain a desired thickness and density, the papermaking body is preferably compressed at 1 to 30 MPa for 1 to 5 minutes.

(Step of heat treatment after compression)
Although this process is not necessarily a process to perform, it is performed as needed according to the material structure of a retainer (glass nonwoven fabric). By heat-treating the compression body at a temperature equal to or higher than the softening point of the resin in this step, the resin is softened and the glass fibers can be bonded to each other, or the clay mineral can be reliably adhered to the glass fibers. The retainer can be provided with flexibility by coating a part or all of the surface of a viscous mineral or the like with a resin. Furthermore, the resin can be partially decomposed to improve the electrolyte retention.

  The treatment temperature is not necessarily limited because it depends on the softening point of the resin, but it is preferably performed at 100 to 200 ° C. By setting the treatment temperature to 100 ° C. or higher, glass fibers, viscous minerals and the like tend to be bound to each other, and by setting the processing temperature to 200 ° C. or lower, the manufacturing process is easily simplified. In addition, you may perform heat processing, pressing suitably according to the constituent material of a retainer, combining with the pressurization process mentioned above.

<Production of control valve type lead acid battery>
The positive electrode active material is lead powder containing lead monoxide as a main component, added with red lead, and mixed with a predetermined amount of water and dilute sulfuric acid. After filling, aging and drying are performed under predetermined conditions. Here, by changing the addition amount of water and dilute sulfuric acid, aging and drying conditions, the surface area of the active material of the positive electrode plate in the fully charged state can be adjusted within a certain target range after the formation.

  The negative electrode active material is a powder of lead alloy containing lead powder containing lead monoxide as a main component, mixed with an additive, and mixed with a predetermined amount of water and dilute sulfuric acid. After filling, aging and drying are performed under predetermined conditions. Here, the surface area of the active material of the negative electrode plate in the fully charged state can be adjusted within a certain range after the chemical conversion by changing the addition amount of the additive, water and dilute sulfuric acid, aging and drying conditions. It is possible to adjust the surface area of the positive and negative electrode active materials by changing the chemical conversion conditions. Further, the amount of the positive and negative electrode active materials can be adjusted by changing the amount of the paste-like active material filled in the lead alloy current collector.

  As the additive added to the paste-like negative electrode active material, an acid-resistant fiber for reinforcement, a lead sulfate crystal growth inhibiting additive, and a shrinkage preventing agent are used. As the acid-resistant fiber for reinforcement, acrylic fiber, polyester fiber, polyethylene terephthalate (PET) fiber or the like can be used, and it is desirable to use PET fiber from the viewpoint of price and acid resistance. By using the acid-resistant fiber for reinforcement, when the active material is filled into the lattice substrate, it is possible to prevent the active material from coming off and falling off. In general, barium sulfate is used as a lead sulfate crystal growth inhibiting additive. When barium sulfate is used, it does not dissolve in the electrolytic solution and remains in the active material, so that it becomes a crystal nucleus of lead sulfate generated at the time of discharge and fine lead sulfate can be formed. Lignin sulfonate is used as the anti-shrinking agent, and lignin sulfonate includes synthetic lignin and natural lignin derived from trees. desirable. By adding lignin, it is possible to prevent the negative electrode active material from being changed in shape during charge and discharge and to be aggregated, and to maintain the surface area of the active material.

  As an additive added to the paste-like positive electrode active material, acid-resistant fibers for reinforcement and red lead are used. As the acid-resistant fiber for reinforcement, acrylic fiber, polyester fiber, PET fiber or the like can be used, and it is desirable to use PET fiber from the viewpoint of price and acid resistance. By using the acid-resistant fiber for reinforcement, when the active material is filled into the lattice substrate, it is possible to prevent the active material from coming off and falling off. The red lead contributes to the improvement of the chemical conversion at the time of battery case formation, and also contributes to increasing the surface area of the positive electrode active material and increasing the utilization rate of the positive electrode active material. In order to achieve both the chemical conversion of the active material and the durability of the active material, it is desirable to add 5 to 25% by mass of red lead with respect to the lead powder. When the amount of lead is less than 5%, the effect of the lead is not sufficiently exhibited, and when it is 25% or more, the durability of the active material is remarkably lowered.

  The lead alloy for forming the positive electrode current collector is made of a lead-calcium-tin alloy. By making calcium content and tin content calcium: 0.08 mass% and tin: 1.6 mass% with respect to lead, the alloy composition becomes dense and a positive electrode current collector excellent in corrosion resistance is formed. It becomes possible to do.

  The lead alloy for forming the negative electrode current collector is not particularly limited, but it is common to use pure lead, calcium-tin alloy, antimony alloy, and from the viewpoint of life performance and ease of manufacturing. It is desirable to use a calcium-tin alloy.

  The positive and negative electrode plates are obtained by filling each of the paste-like active materials described above into a current collector, aging and drying. The current collector can be produced by an expanding method, a casting method, a forging method, or the like.

  In the control valve type lead storage battery of the present embodiment, for example, as shown in FIG. 1, a lead storage battery is assembled, and a predetermined amount of electrolyte is injected to form a battery case. When a plurality of cell chambers are provided in the battery case, electrode plate groups are accommodated in each cell chamber, and a predetermined polarity is obtained by mutually connecting between the electrode plate groups accommodated in the adjacent cell chambers and the opposite polarity straps. A lead storage battery having a rated voltage and a rated capacity may be configured. In the case of a single-cell battery case, terminals of a plurality of lead storage batteries can be connected in parallel or in series using a conductive plate to constitute a battery having a predetermined voltage and capacity.

  Examples of the present invention will be described below. In the following examples and comparative examples, a positive electrode plate and a negative electrode plate described below were used in common.

<Preparation of positive electrode plate>
A lead-calcium-tin alloy (calcium content: 0.08%, tin content: 1.6% mass ratio) is melted and length: 116.0 mm, width: 58.0 mm, thickness, depending on the casting method : A 4.05 mm grid (current collector) was produced. Obtained by kneading with 0.15% PET fiber, 16% water, and 17% dilute sulfuric acid with a specific gravity of 1.280 for 100% lead powder containing lead monoxide as a main component. The obtained paste-like active material was filled into a lattice. After filling the lattice body with the paste-like active material, a positive electrode unformed plate was produced through the following aging and drying conditions.
Aging condition 1: temperature: 80 ° C., humidity: 98%, time: 10 hours Aging condition 2: temperature: 65 ° C., humidity: 75%, time: 13 hours Aging condition 3: temperature: 40 ° C., humidity: 65% Time: 40 hours Drying conditions: Temperature: 60 ° C, Time: 24 hours

<Preparation of negative electrode plate>
A lead-calcium-tin alloy (calcium content: 0.1%, tin content: 0.2% mass ratio) is melted and length: 116.0 mm, width: 58.0 mm, thickness, depending on the casting method : A 2.5 mm grid (current collector) was produced. 10% concentration of 0.03% PET fiber, 1.0% barium sulfate, 10% water, and lignin sulfonate dissolved in water for 100% lead powder containing lead monoxide as the main component After adding dilute sulfuric acid having an aqueous solution of 0.2% and a specific gravity of 1.280 at a mass ratio of 14%, a paste-like active material prepared by kneading was filled in the lattice. After the paste body was filled with the paste-like active material, it was aged and dried under the following conditions to produce a negative electrode unformed plate.
Aging condition: Temperature: 40 ° C., Humidity: 98%, Time: 40 hours Drying condition: Temperature: 60 ° C., Time: 24 hours

<Production of retainer>
With reference to Table 1, the retainer (glass nonwoven fabric) which concerns on an Example and a comparative example is demonstrated. Glass fiber having a fiber diameter of 1.0 μm or less is 50% by mass to 75% by mass, glass fiber having a fiber diameter of more than 1.0 μm and 4.0 μm or less is 25% by mass to 50% by mass, and aggregates with respect to the total glass fiber mass. 3% by mass of aluminum sulfate as an agent and 5% by mass of a polypropylene emulsion resin as a binder were added to make a glass nonwoven fabric having a basis weight of 2.3 g / m ² .

<Production of battery>
Three prepared unformed positive electrode plates and four unformed negative electrode plates were alternately laminated through the produced glass nonwoven fabric to prepare an electrode plate group. The prepared electrode plate group was inserted into the battery case, and after the positive electrode terminal and the negative electrode terminal were welded to the electrode plate group, the battery case was sealed. Next, an electrolytic solution containing dilute sulfuric acid having an aluminum ion concentration of 0 to 0.25 mol / L as a main component was injected from the exhaust plug port, and then a battery case was formed. Thereby, the control valve type lead acid battery was obtained. The battery tank formation conditions were as follows: water temperature: 40 ° C., amount of electricity applied: 250% of the theoretical amount of electricity generated by the positive electrode active material, and time: 60 hours.

(Discharge test)
The rated capacity confirmation test was conducted at 0.05 CA. That is, after the fully-charged control valve type lead storage battery was allowed to stand at 25 ° C. for 24 hours, it was discharged at 0.05 CA to a final voltage of 1.75 V, and the discharge capacity at that time was measured. After that, constant current-constant voltage charging is performed for 16 hours at a constant current charge of 2.45V at a current value of 0.1 CA and constant voltage charge at 2.45V at an ambient temperature of 25 ° C. It was.

  The high rate discharge capacity confirmation test was conducted at 3.0 CA. That is, the control valve type lead-acid battery after being fully charged was allowed to stand at 25 ° C. for 24 hours, and then discharged to 3.0 V at a final voltage of 1.6 V, and the discharge capacity at that time was measured. Thereafter, a constant current charge to a set voltage of 2.45 V at a current value of 0.1 CA at an ambient temperature of 25 ° C., and a constant current-constant voltage charge at a constant voltage of 2.45 V were performed to obtain a fully charged state.

(Life test)
The control valve type lead-acid battery after full charge, which was allowed to stand for 24 hours at an ambient temperature of 25 ° C., was subjected to constant voltage charge of 2.275 V for 22 hours. After that, the battery was discharged at 0.2 CA to 40% of the rated capacity, charged to 0.275 V at 0.2 CA, and constant current-constant voltage charging was performed at a constant voltage of 2.275 V. The battery life was determined when the final discharge voltage when discharging to 40% of the rated capacity at 0.2 CA was 1.4V.

<Test results>
Table 2 shows the mass of the glass fiber having a fiber diameter of 1.0 μm or less, the rated capacity of the control valve type lead storage battery, the 3CA discharge capacity, and the life performance in the produced glass nonwoven fabric in ratios based on Comparative Example 1. From Table 2, both the rated capacity ratio, the 3CA discharge capacity ratio, and the life performance ratio were improved when the glass fiber number ratio of 1.0 μm or less was in the range of 55 to 70. This is considered to be because the glass surface area in the same volume increases as the glass fiber number ratio of 1.0 μm or less increases, and the number of hydroxyl groups in the glass surface increases, so that the electrolyte solution is delivered better. In addition, when the glass fiber number ratio is increased to 1.0 μm or less, the glass nonwoven fabric is loosened when the electrolytic solution is injected, and the pressurization of the electrode is sufficiently ensured. Moreover, when the glass fiber number ratio of 1.0 μm or less exceeds 70%, the structure of the glass nonwoven fabric becomes very fragile, the structure cannot be maintained due to gas generation and liquid diffusion during the formation of the battery case, the structure is destroyed, and the electrolysis It is thought that the battery characteristics were significantly deteriorated because the liquid could not be maintained.

  From Comparative Examples 1 and 2 in Table 2, the discharge performance declined when the aluminum ion concentration in the electrolyte solution after battery case formation was high, but in the range of 1.0 μm or less glass fiber number ratio 55 to 70, the discharge performance by aluminum ions The decrease was reduced. When the glass fiber number ratio is 1.0 μm or less, the glass surface area in the same volume increases, and the number of hydroxyl groups in the glass surface increases. Therefore, aluminum ions in the electrolytic solution are easily trapped on the glass fiber surface and inhibit the positive electrode reaction. It is thought to prevent. In addition, it is considered that the life performance is improved because the charging performance is improved as the concentration of aluminum ions is increased due to the effect of aluminum ions, and the generation of the lead sulfate layer generated at the interface between the current collector and the positive electrode active material is suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, while having favorable discharge performance, even if it is operated by the standby use which discharges about 30% of discharge depth every several months, the lead storage battery which has a favorable lifetime characteristic is provided.

DESCRIPTION OF SYMBOLS 1 ... Lead storage battery, 2 ... Positive electrode plate, 3 ... Negative electrode plate, 4 ... Separator, 5 ... Battery case, 6 ... Cover body.

Claims (2)

A positive electrode plate;
A negative electrode plate;
A glass nonwoven fabric provided between the positive electrode plate and the negative electrode plate;
An electrolyte containing aluminum ions;
With
The glass nonwoven fabric contains 55 to 70 parts by mass of glass fiber having a fiber diameter of 1.0 μm or less with respect to 100 parts by mass of the total mass of the glass fibers constituting the glass nonwoven fabric.
A lead-acid battery operated in a charged state of 95 to 100% when the fully charged state is 100%.   The lead acid battery of Claim 1 whose aluminum ion concentration of the said electrolyte solution is 0.002-0.2 mol / L.

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