JP2006318659A - Lead-acid battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead-acid battery suitable for a business-use car such as a bus or a truck, or a cycle service-use car by improving deep discharge life characteristics. <P>SOLUTION: The lead-acid battery is equipped with an electrode plate group comprising a negative plate, a positive plate having a positive electrode grid containing at least Sb, and a separator whose main component is glass fibers having a diameter of 5.0 μm or less, and the positive plate and the negative plate are immersed in an electrolyte. Preferably, the pressure applied to the electrode plate group ia set to 4.9-29.4 kPa and the diameter of the glass fibers is set to 0.5-1.5 μm. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lead-acid battery.

  A lead acid battery is a battery that uses lead dioxide as a positive electrode active material, lead as a negative electrode active material, and dilute sulfuric acid as an electrolyte. It has a long history, and is the most widely used secondary battery such as automobile power supplies, power storage power supplies, large and small mobile power supplies, and communication power supplies.

  In particular, the liquid lead-acid battery is configured in a state in which dilute sulfuric acid, which is an electrolytic solution, is completely immersed in the positive electrode plate, the negative electrode plate, and the separator. In such a liquid lead-acid battery, the electrolytic solution decreases during use due to the decomposition reaction of water in the electrolytic solution.

  Such a water decomposition reaction rate is greatly influenced by the hydrogen overvoltage of the negative electrode plate. In particular, Sb contained in Pb lowers the hydrogen overvoltage of the negative electrode plate. Decrease.

  In order to suppress such a decrease in the electrolytic solution, a battery using a Pb—Ca alloy as a positive / negative bipolar grid is also widely used (see Patent Document 1). However, Sb contained in the positive electrode lattice improves the bonding force between the lattice and the active material and between the active material particles (see Patent Document 2). In addition, Sb contained in the negative electrode lattice decreases the hydrogen overvoltage and increases the amount of charge electricity at the time of constant voltage charging, so that the charge / discharge cycle life including particularly deep discharge is improved.

Such lead-acid batteries containing Sb in the grid have the disadvantage that the liquid reducing performance is inferior and the frequency of water replenishment is high, but the life in deep discharge such as for buses, trucks, taxis or cycle services Used in fields where characteristics are required.
JP-A-6-267544 JP-A-4-132167

  The present invention provides a lead storage battery using a Pb—Sb alloy for the positive electrode as described above, and further provides a lead storage battery with excellent deep discharge life characteristics, and suppresses a decrease in capacity even if the electrolyte level is slightly reduced. An object of the present invention is to provide a lead acid battery.

  In order to solve the above-described problems, the invention according to claim 1 of the present invention includes a negative electrode plate, a positive electrode plate provided with a positive electrode lattice made of at least a Pb—Sb alloy, and glass fibers having a fiber diameter of 5.0 μm or less. A lead storage battery comprising an electrode plate group including a mat-like separator as a main component, wherein the positive electrode plate and the negative electrode plate are immersed in an electrolytic solution.

  Further, the invention according to claim 2 of the present invention is characterized in that, in the lead storage battery of claim 1, a group pressure applied to the electrode plate group is set to 4.9 kPa to 29.4 kPa.

  The invention according to claim 3 of the present invention is characterized in that, in the lead-acid battery of claim 1 or 2, the fiber diameter of the glass fiber is set to 0.5 μm to 1.5 μm.

  The lead storage battery of the present invention having the above-described configuration has a deep discharge life characteristic superior to that of the conventional one, and can suppress a decrease in discharge capacity even by a decrease in the electrolyte surface.

  Hereinafter, a lead storage battery according to an embodiment of the present invention will be described with reference to the drawings.

  As shown in FIG. 1, the lead storage battery 1 of the present invention is mainly composed of a positive electrode plate 2 having a positive electrode lattice containing Sb such as a Pb—Sb alloy, a negative electrode plate 3, and a glass fiber having a fiber diameter of 5.0 μm or less. An electrode plate group 9 including a mat-like separator 4 is provided.

  Furthermore, the lead storage battery 1 of the present invention has an electrolytic solution 5 that immerses the electrode plate surfaces of the positive electrode plate 2 and the negative electrode plate 3.

  The lead storage battery of the present invention having the above-described configuration has excellent deep discharge life characteristics. In addition, particularly excellent life characteristics can be obtained by setting the group pressure applied to the electrode plate group to 4.9 kPa to 29.4 kPa. Further, when the fiber diameter of the glass fiber is 0.5 μm to 1.5 μm, further excellent life characteristics can be obtained. Further, even when the electrolytic solution surface 5a is lowered, it is possible to suppress the reduction in the 5-hour rate discharge capacity.

  The positive electrode lattice used in the lead storage battery of the present invention contains Sb necessary for obtaining a good bonding force between the positive electrode active materials and between the positive electrode active material and the lattice. For example, a Pb—Sb alloy containing about 1.0 to 5.0% by mass of Sb can be used as the positive electrode lattice. Further, a Pb alloy such as a Pb—Ca alloy or a Pb—Ba alloy that does not contain Sb as a base material is used as a positive electrode lattice, and an Sb or Pb—Sb alloy layer is formed on the surface of the positive electrode lattice in contact with the active material. May be.

  In the present invention, the negative electrode lattice is not particularly limited, but conventionally used Pb—Sb alloy, Pb—Ca alloy, Pb—Sn alloy, and Pb—Ba alloy can be used. Moreover, the Pb-Sb alloy and the Pb-Sn alloy which are conventionally used can also be used for the strap 6 that collectively welds the electrode plates having the same polarity.

  The lead storage battery 1 of the present invention has a path 7 in the battery exterior 8 for releasing oxygen / hydrogen gas generated inside the battery to the outside of the battery. As a method of forming the path 7, a configuration in which an exhaust plug having an exhaust hole is attached to a liquid port provided on a battery lid or the like, as in a conventional lead storage battery, can be applied. In addition, since it is sufficient that oxygen / hydrogen gas can be released outside the battery and an abnormal increase in battery internal pressure can be suppressed, a valve mechanism having a valve opening pressure lower than the battery internal pressure allowable from the pressure resistance strength of the battery exterior 8 is provided on the path 7. It may be provided.

  Hereinafter, the features and effects of the lead storage battery of the present invention will be described in detail.

  The following batteries of the present invention and comparative batteries were prepared, and the number of life cycles and initial discharge capacity of each battery were measured.

(Battery A1 to Battery A25)
Battery A1 to Battery A25 (hereinafter collectively referred to as battery group A). Is a battery using a cast lattice body made of a Pb—Sb alloy containing 2.5% by mass of Sb as a positive electrode lattice and a separator made of a glass fiber mat.

The positive electrode grid is filled with an active material paste for positive electrode obtained by kneading lead powder containing lead monoxide, metallic lead and red lead (Pb ₃ O ₄ ) with water and dilute sulfuric acid, and aged and dried. A positive electrode plate in an unformed state was prepared.

  The negative electrode plate is obtained by adding barium sulfate, lignin and carbon to lead powder containing lead monoxide and metal lead as a component in a cast grid made of a Pb—Ca alloy containing 0.07% by mass of Ca. The negative electrode active material paste obtained by kneading with sulfuric acid was filled and aged and dried to prepare an unformed negative electrode plate.

  A 55D23 type (12V48Ah) battery defined by JIS D5301 (lead storage battery for starting) was prepared using the above-described five positive electrode plates and six negative electrode plates. A glass fiber mat separator having a thickness of 1.0 mm when pressed with 19.6 kPa was used.

  In the battery group A, as shown in Table 1, the fiber diameter of the glass fiber mat was changed to 0.2 μm to 15 μm, and the group pressure was changed from 0 kPa to 39.2 kPa. The group pressure of 0 kPa is a state in which the positive electrode plate and the negative electrode plate are in contact with the separator.

In addition, the Pb-2.5 mass% Sn alloy which does not contain antimony was used for the strap of a positive electrode and a negative electrode. After assembling the battery, dilute sulfuric acid with a density of 1.200 g / cm ³ (when converted to 20 ° C.) is added from the liquid port provided on the battery lid to form a battery case. The electrolyte surface was adjusted to a position of 25.0 mm upward from the upper surfaces of the positive and negative electrode straps at 280 g / cm ³ (when converted to 20 ° C.).

  After adjusting the electrolyte density and the liquid level, an exhaust plug was attached to the liquid port. The exhaust plug is provided with an exhaust hole for discharging oxygen / hydrogen gas generated in the battery to the outside of the battery.

(Battery B1 to Battery B25)
Battery B1 to Battery B25 (hereinafter collectively referred to as battery group B). Is a battery using a cast lattice body made of a Pb—Sn—Ca alloy containing 1.2 mass% Sn and 0.07 mass% Ca instead of the positive electrode grid of the Pb—Sb alloy used in the battery group A. Other configurations are the same as those of the battery group A. When the Sb quantitative analysis in this positive electrode lattice alloy was conducted, it was less than 0.0001 mass% which is a detection limit as Sb density | concentration in Pb alloy, and Sb was not included substantially.

  Similar to the battery group A, as shown in Table 2, for the battery group B, the fiber diameter of the glass fiber mat was changed from 0.2 μm to 15 μm, and the group pressure was changed from 0 kPa to 39.2 kPa. The group pressure of 0 kPa is a state in which the positive electrode plate and the negative electrode plate are in contact with the separator.

(Batteries C1 to C6)
Batteries C1 to C6 (hereinafter collectively referred to as battery group C) are batteries using polyethylene sheet separators having micropores of 0.1 μm to 5 μm instead of the glass fiber mat separator used in battery group A. Other configurations are the same as those of the battery group A.

  The thickness of the polyethylene sheet separator is 0.5 mm, and a plurality of strip ribs having a height of 0.5 mm are provided on the surface facing the positive electrode plate in parallel in the vertical direction of the electrode plate at intervals of 7.0 mm. Therefore, the total thickness of this separator is 1.0 mm.

  Similar to the battery group A, as shown in Table 3, for the battery group C, the group pressure was changed from 0 kPa to 39.2 kPa. In the case of the group pressure of 0 kPa, the positive electrode plate and the negative electrode plate are in contact with the tips of the ribs provided on the separator.

(Batteries D1 to D6)
The batteries D1 to D6 (hereinafter collectively referred to as the battery group D) are replaced with the positive electrode lattice of the Pb—Sb alloy used in the battery group C, 1.2 mass% Sn and 0.07 mass%. The battery uses a cast lattice body made of a Pb—Sn—Ca alloy containing Ca, and the other configuration is the same as that of the battery group C.

  As with the battery group C, as shown in Table 4, the group pressure of the battery group D was changed from 0 kPa to 39.2 kPa. In the case of the group pressure of 0 kPa, the positive electrode plate and the negative electrode plate are in contact with the tips of the ribs provided on the separator.

  About each battery of above-mentioned battery group AD, the heavy load life test (40 degreeC) prescribed | regulated by JISD5301 and the 5-hour rate discharge capacity test were done. Each test condition is shown below.

(Heavy load life test)
(1) Discharge 20A, 1 hour (2) Charge 5A, 5 hours (3) Capacity check Discharge-charge of the above (1) and (2) every 25 times, 20A discharge
(End voltage 10.2V)
(4) Charging after capacity confirmation Charge 5A and charge the battery until the terminal voltage of the storage battery measured every 15 minutes reaches a constant value three times continuously. (5) Life judgment The discharge capacity in (3) is The point of time when the pressure drops to 24 Ah is defined as the life.

(5-hour rate discharge capacity test)
(1) Discharge 9.6A (end voltage 10.5V)
The 5-hour rate discharge capacity is obtained from the product of the discharge current and the discharge time.

  For the 5-hour rate discharge capacity test, the electrolyte surface is in an initial state where the electrolyte surface is 25.0 mm above the upper surface of the positive and negative straps (“liquid surface normal” state), and the moisture in the electrolyte solution Was intentionally evaporated to measure the state in which the upper part of the negative electrode plate was exposed to the electrolyte (“liquid level lowered” state).

  The degree of exposure of the upper part of the negative electrode plate was such that the upper part 30 mm was exposed from the electrolyte with respect to the height dimension 110 mm of the negative electrode plate surface. Here, the battery with the liquid spigot removed was heated in a constant temperature and humidity chamber with a temperature setting of 50 ° C. and a humidity setting of 0 RH% to evaporate water in the electrolyte.

  Tables 5 to 8 show the heavy load life test results and 5-hour rate discharge capacity test results of the respective batteries described above.

(Heavy load life test results)
From the results shown in Table 1, the number of life cycles varies significantly depending on the fiber diameter of the glass fiber, and excellent life characteristics can be obtained in the range of the fiber diameter of 5.0 μm or less, particularly 0.5 μm to 1.5 μm. A particularly excellent life characteristic can be obtained within a range.

  In particular, even better life characteristics can be obtained with a group pressure of 4.9 kPa to 29.4 kPa. When an appropriate group pressure is applied to the fiber mat, dropping of the positive electrode active material is suppressed, and good deep discharge life characteristics are obtained.

  However, when the group pressure is 39.2 kPa, the life cycle number slightly decreases. This is because, due to the group pressure, the pore volume in the separator and the size of the pores are reduced, and ion diffusion in the electrolytic solution is slightly inhibited.

  When the fiber diameter is 0.2 μm, the life characteristics tend to be slightly lower than when the fiber diameter is 0.5 μm. When the fiber diameter is 0.2 μm, it is considered that the pore size in the separator is reduced even at a relatively low group pressure, the electrical resistance is increased, and as a result, the life is slightly reduced.

  When the fiber diameter is 15 μm, even if the group pressure is changed, the positive electrode active material drop-off suppressing effect by the glass fiber mat is hardly obtained. It is presumed that the size of the pores formed by the glass fibers is increased, and the glass fibers are in a state in which the active material particles cannot be effectively prevented from falling off. If the pore size is too large with respect to the active material particle diameter, it is considered that the holding effect of the active material particles by the glass fiber mat is extremely lowered.

  On the other hand, from the results shown in Table 2, the battery group B in which the positive electrode lattice alloy does not contain Sb and is a Pb—Sn—Ca alloy does not greatly affect the life characteristics even if the glass fiber diameter or the group pressure is changed. In addition, inferior life characteristics were obtained even when compared with the battery of the present invention.

  From the results shown in Table 7 and Table 8, the battery group C and the battery group D using the polyethylene sheet separator were compared with the battery group A and the battery group B using the glass fiber mat. It was not affected and only a life cycle number of about 220 to 270 cycles could be obtained.

  From these, in order to significantly improve the life characteristics in the heavy load life test, that is, the deep discharge life characteristics, a glass fiber mat separator containing Sb as a positive electrode lattice alloy and having a fiber diameter in a specific range is used. It is necessary to satisfy the configuration used at the same time. The life improvement effect of the present invention is synergistic because the effect of maintaining the positive electrode active material by the glass fiber mat and the effect of maintaining the lattice-active material interface in a good state by Sb in the positive electrode lattice are obtained at the same time. It is considered to be an effect.

(5 hour rate discharge capacity test results)
Regarding the 5-hour rate discharge capacity, in a state where the liquid level is normal, the characteristics satisfying the standard (48 Ah) were obtained for all the batteries. However, the batteries belonging to the battery group C and the battery group D using the polyethylene sheet separator have a lower liquid level than the batteries belonging to the battery group A and the battery group B using the glass fiber mat as a separator. There is a tendency for the discharge capacity to decrease significantly.

  Such a tendency is particularly remarkable in the battery group C in which the positive electrode lattice alloy contains Sb. When the electrode plate is exposed from the electrolytic solution, Sb in the positive electrode lattice alloy moves to the negative electrode, and the negative electrode is more oxidized. It seems that the situation was easy.

  On the other hand, regarding the batteries A1 to A24 of the present invention and the batteries B1 to B24 of the comparative examples, the decrease in the discharge capacity due to the decrease in the liquid level was remarkably suppressed even when the negative electrode plate was exposed. In each battery belonging to the battery group C containing Sb in the positive electrode lattice alloy, the discharge capacity reduction at the time of liquid level reduction was significant compared to the battery group D using the positive electrode lattice alloy not containing Sb, and similarly In addition, the discharge capacity reduction at the time of liquid level reduction of the batteries A25 to A30 of the comparative example containing Sb in the positive electrode lattice alloy is remarkable as compared with the batteries B25 to B30 of the comparative example using the positive electrode lattice alloy not containing Sb. In view of this, it can be said that the effects of suppressing the decrease in the discharge capacity in the batteries A1 to A24 of the present invention are relatively remarkable in the batteries B1 to B24 of the non-comparative examples.

  Even when the negative electrode plate is exposed from the electrolyte surface, it is replenished to the electrode plate exposed from the electrolyte solution due to the capillary phenomenon of the glass fiber mat, and the replenished electrolyte solution contributes to the discharge reaction, and the electrolyte solution It is thought that the oxidation of the negative electrode was suppressed by covering the negative electrode surface.

  The battery A26 to battery A30 and the battery B26 to battery B30 in which the fiber diameter of the glass fiber is 15 μm have a large capacity drop when the liquid level is lowered. This is presumably because the capillary diameter did not act effectively because the fiber diameter was large, and the electrolyte solution was not sufficiently replenished to the exposed negative electrode plate.

  In addition, the batteries A1 to A6 and the batteries B1 to B6 having a glass fiber diameter of 0.2 μm have a slightly lower discharge capacity when the liquid level is lower than batteries having a glass fiber diameter of 0.5 μm to 5 μm. There is a tendency. This is considered to be due to the fact that the volume of electrolyte retained by decreasing the volume of pores in the separator was decreased, and that the size of the pores was reduced, and the diffusion of the electrolyte was slightly inhibited.

  Therefore, the capacity | capacitance fall at the time of a liquid level fall can be suppressed notably by setting a glass fiber diameter to 5.0 micrometers or less like this invention. In particular, as described above, the glass fiber diameter is preferably in the range of 0.5 μm to 5.0 μm.

  Furthermore, the capacity | capacitance fall can be suppressed more by making the group pressure added to a glass fiber mat into 29.4 kPa or less. When the group pressure is 39.2 kPa, the pore volume in the glass fiber mat is reduced, the amount of electrolyte retained in the pores is reduced, the size of the pores is reduced, and the degree of diffusion of the electrolyte Therefore, it is considered that the decrease in discharge capacity at the time of liquid level increase increases.

  As described above, it can be seen that the lead storage battery of the present invention has excellent deep discharge life characteristics. In particular, a liquid lead-acid battery may be used in a state where the liquid is reduced while the battery is in use and the electrolyte is not replenished. In the lead storage battery of the comparative example, the discharge capacity rapidly decreases in such a case, but in the lead storage battery of the present invention, it is possible to suppress such a rapid discharge capacity decrease due to the decrease in the electrolyte surface.

  The lead storage battery according to the present invention has excellent deep discharge life characteristics and excellent capacity maintenance characteristics when the electrolyte level is lowered. Therefore, the lead storage battery for business vehicles such as buses and trucks, and cycle service It is particularly suitable as a lead storage battery.

The figure which shows the principal part cross section of the lead acid battery of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lead acid battery 2 Positive electrode plate 3 Negative electrode plate 4 Separator 5 Electrolyte 5a Electrolyte surface 6 Strap 7 Path | route 8 Battery exterior 9 Electrode plate group

Claims (3)

A positive electrode plate group comprising a negative electrode plate, a positive electrode plate including a positive electrode lattice containing at least Sb, and a separator mainly composed of glass fibers having a fiber diameter of 5.0 μm or less, wherein the positive electrode plate and the negative electrode plate are used as an electrolyte solution; A lead-acid battery characterized by being immersed. The lead acid battery according to claim 1, wherein a group pressure applied to the electrode plate group is set to 4.9 kPa to 29.4 kPa. The lead acid battery according to claim 1 or 2, wherein a fiber diameter of the glass fiber is set to 0.5 µm to 1.5 µm.

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