JP2006114417A - Lead-acid storage battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that Sb is eluted from a negative electrode at over-discharging a battery when a material which has lower hydrogen overvoltage than Pb such as Sb is added to the negative electrode for the purpose of improving charge receiving property in the negative electrode, and that Sb is eluted from the negative electrode and a negative electrode edge is corroded by re-precipitating on the negative electrode edge, and that the service life is deteriorated. <P>SOLUTION: Pb or Pb alloy which does not contain Sb in lattices of a positive electrode and the negative electrode and a connecting member is used, and Sb and Bi which have lower hydrogen overvoltage than Pb are contained in negative electrode active materials, and weight ratio (NAM/PAM) of the negative electrode active materials (NAM) and positive electrode active materials (PAM) constituting a unit cell is made to be 0.7 to 1.3, preferably 0.82 to 1.08. Furthermore, it is preferable that concentration of Sb or Bi in the negative electrode active materials is made to be 0.0004 to 0.006 wt%. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a lead-acid battery.

  Lead-acid batteries are used for vehicle engine start-up and backup power supplies. Among them, the lead acid battery for start-up supplies power to various electric / electronic devices mounted on the vehicle as well as power supply to the engine start cell motor. After the engine is started, the lead storage battery is charged by an alternator. Here, the output voltage and output current of the alternator are set so that charging and discharging of the lead storage battery are balanced and the SOC (charged state) of the lead storage battery is maintained at 90 to 100%.

  In recent years, improvement in fuel efficiency of vehicles has been studied from the viewpoint of environmental conservation. For example, an idle stop vehicle that stops the engine while the vehicle is temporarily stopped, a charge control system that suppresses the amount of power generated by the alternator during acceleration and improves the engine efficiency, and the vehicle's kinetic energy is converted into electric energy. A regenerative braking system that converts this into electrical energy and stores this electrical energy has been put into practical use.

  In a vehicle equipped with a system as described above, the lead storage battery is not charged during idle stop or during alternator power generation suppression. Deepen. Further, in a vehicle equipped with a regenerative braking system, in order to store electric energy during regeneration, it is necessary to control the SOC of the lead storage battery to be about 50 to 90% lower than before, and at the same time, charging and discharging frequently occur. Will be repeated. In addition to being used at low SOC as described above, lead-acid batteries are increasingly discharged due to long-term stopping due to the electrification of vehicle parts, and there are increasing cases of overdischarge. .

  Therefore, in order to adapt to a vehicle equipped with these systems, the lead storage battery is required to have a life characteristic when deep discharge is performed and charge and discharge are frequently repeated. The deterioration factors of lead-acid batteries in such a deep discharge life are the deterioration of the active material in the positive electrode due to the deep discharge and the increase in impedance due to the formation of the high resistance layer at the active material-lattice interface and the decrease in charge acceptance of the negative electrode active material. It was the Lord.

  Since the vehicle charging system is based on constant voltage control, the current droops because the negative electrode potential shifts to the base and the voltage rises to the charge control constant voltage value at an early stage of charging due to the negative charge acceptability decline. To do. Therefore, the lead storage battery cannot secure a sufficient amount of charge electricity, becomes insufficiently charged and has a short life.

  In order to suppress this deterioration, for example, Patent Document 1 discloses that a lead alloy layer containing tin and antimony is formed on the surface of a positive electrode lattice of a lead-calcium-tin alloy. Tin and antimony present on the surface of the positive electrode lattice have an effect of suppressing deterioration of the active material and formation of a high resistance layer at the active material-lattice interface.

  In particular, a part of antimony disposed on the surface of the positive electrode lattice is trapped by the positive electrode active material, but a small amount of the other part elutes in the electrolytic solution and is deposited on the negative electrode plate. Antimony deposited on the negative electrode active material has a function of lowering the charging voltage by preciously shifting the charging potential of the negative electrode. As described above, the reduction of the charging voltage in the constant voltage charging control increases the charging current. As a result, the amount of charged electricity in the positive electrode was secured, and the deterioration of the positive electrode due to insufficient charging and the short life of the lead storage battery due to this were suppressed.

  Such a configuration as disclosed in Patent Document 1 is very effective in a start-up lead-acid battery used in a charged state in which the SOC exceeds 90%, and dramatically improves the life characteristics.

  However, in the above-described idle stop vehicle, charge control system, vehicle equipped with a regenerative brake system, that is, in a use environment with a deeper discharge depth and a higher charge / discharge frequency, only the configuration as in Patent Document 1 is used. In the lead storage battery of this type, although the life of the positive electrode can be ensured, there has been a problem that corrosion proceeds at the negative electrode ear. As a result, the thickness of the negative electrode ear is reduced, the current collection efficiency in the negative electrode is lowered, and the life is shortened.

  Conventionally, with regard to the corrosion of the negative electrode ear, the negative electrode shelf and the negative electrode ear are exposed from the electrolyte solution and exposed to oxygen in the atmosphere, so that the welded portion between the negative electrode shelf and the negative electrode corrodes and breaks at this part. Was known. However, even when the negative electrode shelf and the negative electrode ear are immersed in the electrolyte, Sb contained in the lead alloy connecting member such as Sb arranged on the positive electrode grid, the positive electrode shelf, the positive electrode column, and the positive electrode connector is contained in the electrolyte. It has been found that the negative electrode ears are corroded by being eluted in a small amount and precipitated on the surface of the negative electrode ears.

In Patent Document 2, the positive electrode lattice excluding the negative electrode lattice bone, the positive electrode connection member, the negative electrode lattice ear, and the negative electrode connection member are made of Pb or Pb alloy not containing Sb, and either the negative electrode lattice bone or the negative electrode active material is used. A lead storage battery containing a small amount of Sb that does not affect the amount of liquid reduction has been proposed. Such a configuration suppresses the elution of Sb from the positive electrode and the precipitation of Sb on the negative electrode ear, and improves the battery charge acceptance and deep discharge life by including Sb in the negative electrode active material. Has been.
JP-A-3-37962 JP 2003-346888 A

  The lead storage battery having the configuration of Patent Document 2 as described above can suppress Sb precipitation at the negative electrode ear and negative electrode ear corrosion caused thereby. However, it has been found that Sb in the negative electrode active material is re-eluted into the electrolytic solution and deposited on the negative electrode ears and corrodes the negative electrode ears in a charge / discharge cycle in which overdischarge or rapid discharge is repeated. It was.

  The present invention drastically improves the life characteristics by improving the deterioration of the positive electrode and the charge acceptability at the negative electrode in a use environment with a deep discharge depth and a high charge / discharge frequency as described above, and overdischarge. Afterwards, by preventing the antimony from moving to the negative electrode ear, and suppressing corrosion in the negative electrode ear, it is suitable for highly reliable idle stop vehicles, charge control systems, vehicles with regenerative brake systems, etc. It aims at providing lead acid battery.

  The invention according to claim 1 of the present invention for solving the above-described problem includes a negative electrode lattice comprising a negative electrode lattice ear and a negative electrode lattice bone, and a negative electrode plate comprising a negative electrode active material filled in the negative electrode lattice bone, A positive electrode shelf comprising a positive electrode lattice comprising a positive electrode lattice ear and a positive electrode lattice bone, and a positive electrode plate comprising a positive electrode active material filled in the positive electrode lattice bone, and a positive electrode shelf that collectively welds the positive electrode lattice ear and a positive electrode derived from the positive electrode shelf In a lead storage battery comprising a negative electrode connecting member comprising a positive electrode connecting member comprising a column or a positive electrode connecting body, a negative electrode shelf for collectively welding negative electrode grid ears, and a negative electrode pillar or negative electrode connecting body derived from the negative electrode shelf, The positive electrode grid and the positive electrode connection member are made of lead or a lead alloy not containing Sb, the negative electrode grid and the negative electrode connection member are made of lead or a lead alloy not containing Sb, and hydrogen is contained in the negative electrode active material rather than Pb. A material having a low voltage is included in the negative electrode active material, and the mass ratio (NAM / PAM) of the negative electrode active material (NAM) and the positive electrode active material (PAM) constituting the unit cell is 0.7 to 1.3. The lead acid battery characterized by this is shown.

  The invention according to claim 2 of the present invention is characterized in that, in the lead storage battery of claim 1, the mass ratio (NAM / PAM) is set to 0.82 to 1.08.

  Furthermore, the invention according to claim 3 of the present invention is the lead-acid battery according to claim 1 or 2, wherein the substance having a low hydrogen overvoltage is a substance containing Sb, and the Sb concentration in the negative electrode active material is set to 0. It is characterized by being 0004 to 0.006 mass%.

  According to a fourth aspect of the present invention, in the lead storage battery according to the first or second aspect, the substance having a low hydrogen overvoltage is a substance containing Bi, and the Bi concentration in the negative electrode active material is set at 0. 0. It is characterized by being 0004 to 0.006 mass%.

  According to the lead storage battery of the present invention, the life characteristics are dramatically improved by improving the deterioration of the positive electrode and the charge acceptability at the negative electrode in a use environment with a deep discharge depth and a high charge / discharge frequency. By suppressing the corrosion in the ear portion, it is possible to provide a lead storage battery suitable for a highly reliable idle stop vehicle, a charge control system, a regenerative brake system mounted vehicle, and the like.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  As shown in FIG. 2, the positive electrode plate 2 has a configuration in which a positive electrode active material 24 is filled in a positive electrode lattice 21 including positive electrode lattice ears 22 and positive electrode lattice bones 23. On the other hand, as shown in FIG. 3, the negative electrode plate 3 has a configuration in which a negative electrode active material 34 is filled in a negative electrode lattice 31 composed of negative electrode lattice ears 32 and negative electrode lattice bones 33.

  The lead storage battery 1 of the present invention combines a predetermined number of separators 4, positive electrode plates 2 and negative electrode plates 3, and collectively welds the same polarity ears of the positive electrode grid ears 22 and the negative electrode grid ears 32, respectively. A shelf 6 is formed. The positive electrode shelf 5 is formed with a positive electrode connector 7 or a positive electrode pole column (not shown), and the negative electrode shelf 6 is formed with a negative electrode connector (not shown) or a negative electrode column 8. The example shown in FIG. 1 shows an example in which the positive electrode shelf 5 is provided with the positive electrode connection body 7 and the negative electrode shelf 6 is provided with the negative electrode column 8, but if necessary, the positive electrode connection body 7 and the negative electrode column 8 can be replaced with the positive electrode. The column and the negative electrode connector are joined to the positive electrode shelf 5 and the negative electrode shelf 6, respectively.

  For example, a starting lead storage battery having a nominal voltage of 12 V in which 6 cells are connected in series generally has a positive electrode shelf 5 as shown in FIG. 1 in the electrode plate group constituting the sixth end cell from the positive terminal side. The positive electrode connector 7 is connected to the negative electrode shelf 6, and the negative electrode column 8 is connected to the negative electrode shelf 6. Further, in the electrode plate group constituting the first end cell from the positive electrode terminal side, the positive electrode column is connected to the positive electrode shelf 5 and the negative electrode connector is connected to the negative electrode shelf 6. And the electrode plate group which comprises the intermediate | middle cell located between these end cells takes the structure by which the connection body was connected to both the positive electrode shelf 5 and the negative electrode shelf 6. FIG.

  In the present invention, the positive electrode shelf 5, the positive electrode connection body 7, and / or the positive electrode connection member 9 and the positive electrode lattice 21 formed of the positive electrode column are formed of Pb or Pb alloy not containing Sb. As a Pb alloy not containing Sb, in consideration of corrosion resistance and mechanical strength, a Pb—Sn alloy containing about 0.05 to 3.0 mass% of Sn, or about 0.01 to 0.10 mass%. A Pb—Ca alloy containing Ca or a ternary alloy thereof (Pb—Ca—Sn alloy) can be used.

  On the other hand, with respect to the negative electrode, the negative electrode connection member 10 constituted by the negative electrode shelf 6, the negative electrode connection body 8, and / or the negative electrode pole column, and the negative electrode lattice 31 are made of Pb or Pb alloy substantially free of Sb, like the positive electrode. . As a Pb alloy not containing Sb, in consideration of corrosion resistance and mechanical strength, a Pb—Sn alloy containing about 0.05 to 3.0 mass% of Sn, or about 0.01 to 0.10 mass%. A Pb—Ca alloy containing Ca or a ternary alloy thereof (Pb—Ca—Sn alloy) can be used. Moreover, since the frequency of oxidative corrosion is low in the negative electrode, pure Pb can also be used.

  In addition, addition of an element such as about 0.01 to 0.08 mass% Ba or 0.001 to 0.05 mass% Ag is also preferable for improving the durability of the positive electrode grid. In addition, in manufacturing the lattice body and the connection member having the above composition, in order to suppress the disappearance of Ca oxidation from the molten lead alloy, the addition of about 0.001 to 0.05% by mass of Al It does not impair the effect and is acceptable.

  In the present invention, the negative electrode active material 34 includes a material having a hydrogen overvoltage lower than that of Pb. As the substance having a hydrogen overvoltage lower than Pb, Sb or a compound thereof (Sb oxide, salt such as sulfate) or Bi or a compound thereof (Bi oxide, salt such as sulfate) can be selected. . The appropriate concentration of each of the negative electrode active materials is 0.004 to 0.006% by mass when Sb or a compound thereof is added, and Bi or the compound is added when Bi or a compound thereof is added. A density | concentration shall be 0.0004-0.006 mass%.

  The addition of Sb or Bi to the negative electrode active material may be performed by adding Sb, Bi or a compound thereof to the negative electrode active material paste. Alternatively, the negative electrode plate can be immersed in an electrolyte containing Sb or Bi, for example, a dilute sulfuric acid electrolyte containing Sb ions or Bi ions, and Sb or Bi can be electrodeposited on the negative electrode active material by electrolytic plating.

  By adding it to the negative electrode active material of Sb or Bi, the chargeability of the negative electrode active material is remarkably improved and the life characteristics are improved. In particular, the life characteristics are remarkably improved in the region where the content of Sb or Bi is 0.0004% by mass or more. On the other hand, in the region where the Sb or Bi content exceeds 0.006% by mass, the corrosion of the negative electrode ears gradually begins to progress, so the content concentration is more preferably 0.006% by mass or less.

  And in the lead acid battery of this invention, the mass ratio (NAM / PAM) of the negative electrode active material 34 (NAM) and the positive electrode active material 24 (PAM) which comprises a unit cell, ie, comprises an electrode group, is 0.7-. 1.3, preferably 0.82 to 1.08.

  The lead storage battery of the present invention can be obtained by assembling a lead storage battery using the above electrode group and thereafter immersing the electrode group in an electrolyte according to a conventional method. In the present invention, since the negative electrode active material includes a material having a hydrogen overvoltage lower than Pb, such as Sb and Bi, it is not applied to a control valve type lead-acid battery. This is because when applied to a control valve type lead-acid battery, the control valve is opened due to the generation of a small amount of gas, and air flows into the battery and oxidizes the negative electrode.

  Since the lead storage battery having the above-described configuration of the present invention contains Sb and Bi only in the negative electrode active material, corrosion of the negative electrode ear can be suppressed without Sb from the positive electrode moving to the negative electrode. Sb and Bi contained in the negative electrode lower the overvoltage of the negative electrode, improve charge acceptability, and improve the life characteristics of the lead storage battery.

  On the other hand, even when deep discharge is repeated or overdischarged, the mass ratio (NAM / PAM) of the negative electrode active material (NAM) to the positive electrode active material (PAM) is 0.7 to 1.3, preferably 0.82. By setting it to ˜1.08, elution of Sb and Bi from the negative electrode active material can be suppressed, and reprecipitation to the negative electrode ear and corrosion of the negative electrode ear due to this can be suppressed.

  When the ratio of the mass ratio (NAM / PAM) is less than 0.7, elution of Sb or Bi from the negative electrode active material proceeds when the battery is deeply discharged or overdischarged, and re-deposits on the negative electrode ear. Since the corrosion of the negative electrode ear proceeds rapidly, it is not preferable. In the region of 0.7 or more and less than 0.82, corrosion of the negative electrode ear proceeds, but the degree thereof is moderate. The region of 0.82 or more is most preferable because negative electrode ear corrosion hardly occurs.

  Further, in a region where the mass ratio (NAM / PAM) exceeds 1.08, when the battery is overdischarged, the positive electrode is further deteriorated, and the cycle life characteristics after overdischarge are lowered. Further, in a region where this ratio exceeds 1.3, the cycle life characteristics after overdischarge are further deteriorated, and the excess negative electrode active material increases the weight of the battery, which is not practical. Accordingly, in the present invention, the mass ratio (NAM / PAM) is set to 0.7 to 1.3, preferably 0.82 to 1.08.

  Furthermore, in the present invention, a layer containing Sn having a higher concentration than that of the positive electrode lattice bone is formed on at least a part of the surface of the positive electrode lattice bone in contact with the positive electrode active material. The life characteristics can be improved. This Sn-containing layer suppresses the formation of a high-resistance layer at the positive electrode active material-lattice interface by Sn. Therefore, in order to obtain the effect, the Sn-containing layer contains at least a higher concentration of Sn than the positive electrode lattice matrix. It is necessary. For example, when the positive electrode lattice includes 1.6% by mass of Sn, the Sn amount is at least at a concentration exceeding 1.6% by mass, and is 3.0 to 6.0% by mass. Obviously, if the concentration is lower than that of the positive electrode lattice base material, the Sn concentration on the surface of the lattice is lowered, which is not preferable.

  Create lead-acid battery members such as the positive electrode plate shown below, combine these members to create batteries according to the present invention and comparative examples, and perform life tests to evaluate corrosion of the negative electrode ears and battery life characteristics. went.

1) Positive electrode plate A positive electrode plate was prepared by preparing one type of positive electrode lattice and filling it with a positive electrode active material. The positive electrode lattice uses a Pb—Ca—Sn alloy, and the alloy composition is Pb—0.07 mass% Ca—1.3 mass% Sn. The alloy was rolled in stages to form an alloy sheet, and then expanded to form a positive electrode lattice. In addition, when Sb quantitative analysis in this positive electrode lattice was performed, Sb density | concentration was less than the detection limit (0.0001 mass%).

  By mixing lead powder (mixed powder of metallic lead, lead monoxide and red lead) with water and dilute sulfuric acid to make a positive electrode active material paste, filling the above-mentioned positive electrode lattice in a predetermined amount, and then aging and drying A positive electrode plate was produced.

2) Negative electrode plate A Pb-0.07 mass% Ca-0.25 mass% Sn alloy was rolled in the same manner as the positive electrode, and then subjected to expansion processing to prepare a negative electrode lattice. In addition, when Sb quantitative analysis contained in this positive electrode lattice alloy was performed, Sb density | concentration was less than the detection limit (0.0001 mass%).

  An expander (barium sulfate and lignin) and carbon were added to lead powder (mixed powder of metal lead and lead monoxide) and kneaded with water and dilute sulfuric acid to prepare a negative electrode active material paste. The negative electrode active material paste was filled in a negative electrode lattice, and then aged and dried to obtain a negative electrode plate. In this example, Sb sulfate was added to the negative electrode active material paste, and the Sb concentration in the negative electrode active material in the chemical conversion completed state was 0 (less than 0.0001% by mass, which is the detection limit), 0 Negative electrode plates with .0002 mass%, 0.0004 mass%, 0.006 mass%, and 0.007 mass% were prepared. Further, Bi is added as Bi oxide instead of Sb in the negative electrode active material paste, and the Bi concentration in the negative electrode active material in the chemical conversion completed state is 0 (less than 0.0001% by mass, which is the detection limit), 0. Negative electrode plates with 0002 mass%, 0.0004 mass%, 0.006 mass%, and 0.007 mass% were prepared.

3) Separator As a separator, a 0.3 mm thick microporous polyethylene sheet was folded in a U shape and both sides were heat-sealed to produce a bag-shaped separator with only the upper part opened. The microporous polyethylene sheet used had micropores with a maximum pore diameter of 10 μm. A positive electrode plate was accommodated in this bag-like separator.

4) Lead alloy for positive electrode connection member and alloy for negative electrode connection member As alloys for positive electrode connection member and negative electrode connection member, Pb-2.5 mass% Sn alloy (alloy A) and Pb-2.5 mass% Sb alloy (alloy) B) was prepared. In addition, when Sb quantitative analysis in the alloy A was performed, Sb density | concentration was less than the detection limit (0.0001 mass%).

Example 1
Using the above-described positive electrode plate, negative electrode plate, bag-shaped separator, and positive / negative electrode connection member alloy in combinations shown in Tables 1 and 2, an electrode plate group consisting of 5 positive electrode plates and 6 negative electrode plates per cell A liquid type 55D23 type lead acid battery for starting (12V48Ah) was prepared. In Example 1, the presence or absence of Sb in the negative electrode active material was examined.

  Each battery shown in Table 1 and Table 2 was subjected to a cycle life test after overdischarge. Overdischarge was performed under the following test conditions. That is, in a 25 ° C. atmosphere, the test battery is discharged at 10 A to 10.5 V. Thereafter, a 12 W bulb was connected between the battery terminals and left for 48 hours. Thereafter, each battery was charged at a constant voltage of 14.5 V (maximum current 25 A) for 8 hours, and the next cycle life test was performed.

The cycle life characteristics were measured under the following test conditions. In an atmosphere of 25 ° C., 25A discharge for 20 seconds and 14V constant voltage charge (maximum charging current 25A) for 40 seconds are repeated for 7200 cycles, and then the mass loss (W _L ) due to this cycle is measured. Thereafter, the battery is discharged at 300 A for 30 seconds, and the discharge voltage (V ₃₀ ) at 30 seconds is measured. Thereafter, the lead storage battery is replenished with water corresponding to the mass loss (W _L ). The number of charge / discharge cycles until V _{30 for} every 7200 cycles of charge / discharge drops to 7.0V was defined as the number of life cycles. Normally, in a lead acid battery for start-up, the light load life test specified in JIS D5301 is composed of a cycle of 25A discharge 4 minutes and a constant voltage charge 10 minutes with a maximum current 25A. The test conditions were such that the depth of discharge was increased by reducing the charge time / discharge time ratio frequently.

The method for calculating the number of life cycles is as follows. n-th on the measured V ₃₀ voltage (number of charge and discharge cycles 7200 × n), the first time V ₃₀ is equal to or less than 7.0 V, to the V ₃₀ and Vn. Then, last of V ₃₀ voltage of (n-1 time) is taken as Vn-1, the vertical axis V _30, the horizontal axis in the graph of the number of charge and discharge cycles, the coordinates (7200 (n-1), Vn- 1) and coordinates (7200n, Vn) are connected by a straight line L, and the value on the horizontal axis at the intersection of this straight line L and V ₃₀ = 7.0 is defined as the number of life cycles.

Moreover, about each battery which the lifetime test was complete | finished, the decomposition | disassembly investigation of the battery was conducted and the ear corrosion rate of the negative electrode was calculated | required. Note that the negative electrode ear cross-sectional area in the initial state before the test is S, the negative electrode ear cross-sectional area after the life test is SE, and the reduction rate of the ear cross-sectional area obtained as {100 × (S-SE) / S} is the ear corrosion. Rate. The cross-sectional area of the negative electrode ear in the initial state before the test was (width) 13.0 mm × (thickness) 0.7 mm = 9.1 mm ^{2. When} the ear corrosion rate was 50%, the cross-sectional area was 4.55 mm due to corrosion. ^This is equivalent to ² reductions.

  Tables 3 and 4 show the results of the negative electrode ear corrosion rate and the life cycle number in the cycle life test after these overdischarges.

  From Table 4, the negative electrode ear corrosion is remarkable for the battery using the lead alloy containing Sb (alloy B: Pb-2.5 mass% Sb) as the positive electrode and negative electrode connecting members. Then, due to a significant decrease in the cross-sectional area of the negative electrode ear, the discharge voltage was remarkably lowered, and the life was completed after 20000 to 30000 cycles.

  From Table 3, in a battery in which a lead alloy not containing Sb (alloy A: Pb—2.5 mass% Sn) is used for the positive electrode, the negative electrode lattice, and the connecting member, and the negative electrode active material contains Sb, The lead storage battery of the present invention in which the mass ratio (NAM / PAM) of the substance (NAM) to the positive electrode active material (PAM) is 0.7 to 1.3 is less than the lead storage battery of other comparative examples. Corrosion is suppressed and it has a good life cycle number.

  When the mass ratio (NAM / PAM) is 0.6, the negative electrode ear corrosion is remarkable due to the inclusion of Sb in the negative electrode active material, and due to the decrease in the current collecting property, the life ends at over 20000-30000 cycles. . It can be assumed that Sb eluted from the negative electrode due to overdischarge before the life test corroded on the negative electrode ear, and corroded the negative electrode ear through the charge / discharge cycle.

  On the other hand, when the mass ratio (NAM / PAM) was 1.35, the corrosion rate of the negative electrode ear was not so significant, but the life cycle number was 20000 to 40000 cycles. In the case of such a mass ratio, it can be presumed that the capacity of the positive electrode is significantly reduced due to overdischarge, and the cycle life is reduced. Therefore, in the present invention, the mass ratio (NAM / PAM) needs to be in the range of 0.7 to 1.3. Among them, by setting the mass ratio (NAM / PAM) to 0.82 to 1.08, it is possible to obtain a more remarkable life extension effect while more significantly suppressing negative electrode ear corrosion.

  Regarding the Sb concentration in the negative electrode active material, there is an effect of improving the cycle life at 0.0002% by mass or more, but by setting it to 0.0004% by mass or more, it is possible to obtain more stable and high cycle life characteristics. it can. In addition, when the Sb content is 0.007% by mass, the negative electrode ear corrosion rate increases, so the Sb content is preferably 0.006% by mass or less. Therefore, the amount of Sb in the negative electrode active material is more preferably 0.0004 to 0.006% by mass. It is considered that Sb in the negative electrode active material improved the charge acceptability and life characteristics of the negative electrode by making the charge potential of the negative electrode more noble.

(Example 2)
The positive electrode plate, the negative electrode plate, the bag-shaped separator, and the positive and negative electrode connecting member alloys were used in the combinations shown in Tables 5 and 6, and as in Example 1, five positive electrode plates and one negative electrode plate 6 per cell. A liquid type 55D23 type lead acid battery for start-up (12V48Ah) having a group of electrode plates was produced. In Example 2, the presence or absence of Bi in the negative electrode active material was examined.

  Each battery shown in Table 5 and Table 6 was subjected to a cycle life test after overdischarge under the same test conditions as in Example 1. The results are shown in Table 7 and Table 8.

  From the results shown in Table 7 and Table 8, it can be seen that the result of Example 2 in which Bi is added instead of Sb in the negative electrode active material in Example 1 is almost the same as that of Example 1. That is, the battery of the comparative example using the alloy B containing Sb as the bonding member of the positive electrode and the negative electrode has only a life of about 20000 to 30000 cycles, and the corrosion at the negative electrode ear has also progressed.

  On the other hand, the lattice of the positive and negative electrodes and the joining member of the present invention do not contain Sb, and the negative electrode active material contains Bi, and the mass ratio of the negative electrode active material (NAM) to the positive electrode active material (PAM) (NAM / PAM). ) Is 0.7 to 1.3, the lead acid battery of the present invention has a good life cycle number while suppressing negative electrode ear corrosion as compared with the lead acid batteries of other comparative examples.

  In particular, by making the mass ratio (NAM / PAM) 0.82 to 1.08 and the Bi concentration in the negative electrode active material 0.0004 to 0.006% by mass, the negative electrode ear corrosion becomes more prominent. It is possible to obtain a more prominent life extension effect while suppressing the above.

  As described above, it has been confirmed that the lead storage battery according to the configuration of the present invention has extremely good life characteristics even in the cycle life test after overdischarge and can significantly suppress the corrosion of the negative electrode ear.

  As described above, according to the lead-acid battery of the present invention, by improving the positive electrode deterioration in the deep discharge and the charge acceptability in the negative electrode, the deep discharge life characteristics are dramatically improved and the corrosion in the negative electrode ear is suppressed. Therefore, it is suitable for a highly reliable idle stop vehicle, a vehicle equipped with a regenerative brake system, and the like.

Partially broken view showing electrode plate configuration Diagram showing positive electrode plate Diagram showing the negative electrode plate

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Lead acid battery 2 Positive electrode plate 3 Negative electrode plate 4 Separator 5 Positive electrode shelf 6 Negative electrode shelf 7 Positive electrode pillar 8 Negative electrode connection body 9 Positive electrode connection member 10 Negative electrode connection member 21 Positive electrode lattice 22 Positive electrode lattice ear 23 Positive electrode lattice bone 24 Positive electrode active material 31 Negative electrode lattice 32 Negative electrode lattice ear 33 Negative electrode lattice bone 34 Negative electrode active material

Claims (4)

A negative electrode grid including a negative electrode lattice ear and a negative electrode lattice bone, a negative electrode plate including a negative electrode active material filled in the negative electrode lattice bone, a positive electrode lattice including a positive electrode lattice ear and a positive electrode lattice bone, and a positive electrode lattice bone A positive electrode connecting member having a positive electrode plate including a positive electrode active material and having a positive electrode shelf that collects and welds positive electrode grid ears, and a positive pole column or a positive electrode connection body derived from the positive electrode shelf, and the negative electrode grid ears are collectively welded. In a lead storage battery comprising a negative electrode connecting member comprising a negative electrode shelf and a negative electrode column or a negative electrode connecting body derived from the negative electrode shelf, the positive electrode grid and the positive electrode connecting member are made of lead or a lead alloy containing no Sb, The negative electrode grid and the negative electrode connecting member are made of lead or lead alloy not containing Sb, the negative electrode active material contains a substance having a hydrogen overvoltage lower than Pb in the negative electrode active material, and constitutes a unit cell. Lead-acid battery weight ratio of active material (NAM) and the positive electrode active material (PAM) (NAM / PAM) is characterized in that 0.7 to 1.3. The lead acid battery according to claim 1, wherein the mass ratio is 0.82 to 1.08. The lead acid battery according to claim 1 or 2, wherein the substance having a low hydrogen overvoltage is a substance containing Sb, and the Sb concentration in the negative electrode active material is set to 0.0004 to 0.006 mass%. The lead acid battery according to claim 1 or 2, wherein the substance having a low hydrogen overvoltage is a substance containing Bi, and a Bi concentration in the negative electrode active material is set to 0.0004 to 0.006 mass%.