JP5299672B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a lead-acid battery.

In a lead-acid battery including a positive electrode plate produced using a positive electrode active material material containing lead (Pb ₃ O ₄ ), the utilization rate of the positive electrode active material can be improved, and thereby the active capacity required for the same capacity can be improved. It is known that the amount of substance used can be reduced and a battery having a high discharge capacity can be obtained with the same amount of active material.

However, when adding a general lead tan (high lead tan conversion rate lead tan with a lead tan conversion rate of 98 mass% or more, hereinafter simply referred to as “high lead tan conversion rate lead tan”) to the positive electrode active material raw material, There is a problem that the bond between the active material particles is weakened, and the active material is likely to soften and fall off due to repeated charge and discharge, resulting in an early life.
Therefore, in order to solve such a problem, a lead storage battery in which a lead tanning rate of 90% by mass or less is added to a positive electrode active material material has been proposed (see Patent Document 1).

    The lead tanning rate used in the invention described in Patent Document 1 is 90 mass% or less, and the lead tanning rate generally used as a positive electrode active material raw material for lead-acid batteries is 98 mass% or more. Compared with the high lead oxidation rate, there is much PbO that plays an important role in the bonding between the positive electrode active material particles.

  Therefore, according to the method described in Patent Document 1, the bonding between the active material particles is strengthened more than the positive electrode active material produced by adding the high lead oxidation rate, and the active material is softened and dropped off. Since it is difficult, the life performance can be improved.

  However, compared with a lead storage battery including a positive electrode plate made by using only lead powder without adding a lead component, the lead storage battery described in Patent Document 1 tends to soften the active material and has a short life. The life performance was not sufficient.

On the other hand, as a means for suppressing softening of the active material, a lead-acid battery including a positive electrode plate manufactured using a positive electrode active material material obtained by adding an antimony compound to a positive electrode active material has been proposed (see Patent Document 2).
Japanese Patent Publication No. 8-15081 JP-A-10-112111

The present inventors have studied a lead storage battery including a positive electrode plate manufactured using a positive electrode active material material obtained by adding an antimony compound to a positive electrode active material.
As a result, in a lead storage battery including a positive electrode plate manufactured using an active material material to which an antimony compound is added, softening of the active material can be suppressed, but there is a problem that initial capacity is reduced (details) See Example Group 1).

  This invention is completed based on the above situations, Comprising: It aims at providing the lead acid battery which can suppress softening of an active material, without reducing an initial stage capacity | capacitance.

  As a result of intensive studies to solve the above problems, the present inventors have found that the lead active material material has a low lead oxidation rate of 30% by mass to 80% by mass, and an antimony compound. It was found that the addition of the active material can suppress softening of the active material without reducing the initial capacity of the battery.

  That is, the present invention provides a positive electrode plate produced using a positive electrode active material material containing lead powder, a low lead tanning rate of 30 to 80% by mass and an antimony compound. It is the lead acid battery characterized by having provided.

  According to the present invention, the initial capacity of the battery is reduced because the lead active material material is added with a low lead tanning rate of 30% by mass to 80% by mass and an antimony compound. The softening of the active material can be suppressed without causing it to occur.

In the present invention, when the antimony compound is added at a ratio of 0.01 parts by mass or more and 0.2 parts by mass or less as the amount of antimony atoms with respect to 100 parts by mass of the positive electrode active material in terms of PbO ₂ , The capacity is remarkably improved, and the effect of suppressing softening of the active material is increased, which is preferable.
In the present invention, the “mass of the positive electrode active material in terms of PbO ₂ ” refers to the mass determined on the assumption that all of the lead powder and low lead tanning lead used as the positive electrode active material have been oxidized to PbO _2. Say.

  ADVANTAGE OF THE INVENTION According to this invention, the lead acid battery which can suppress softening of an active material, without reducing initial capacity can be provided.

  The lead storage battery (hereinafter also referred to as “battery”) of the present invention includes an electrode plate group including a positive electrode plate, a negative electrode plate, and a separator. In this invention, a well-known thing can be used as a negative electrode plate and a separator.

In this invention, a positive electrode plate is produced using the positive electrode active material raw material containing lead powder, a low lead tanning rate red lead, and an antimony compound.
Although there is no limitation in particular as lead powder used in this invention, For example, what was manufactured by the ball mill method etc. are used.

The low lead tanning rate used in the present invention is usually produced by firing at 350 to 450 ° C., and the lead tanning rate is adjusted by adjusting conditions such as temperature and time during firing. be able to.
As the low lead oxidation rate lead used in the present invention, for example, a powder obtained by firing the lead powder produced by the above ball mill method at 420 ° C. until reaching a predetermined lead oxidation rate can be used.

In this specification, the lead tanning rate refers to the ratio (mass%) of Pb ₃ O ₄ in the baked product when lead powder is baked and lead tanned, and specifically in the baked product. It is represented by a value obtained by multiplying the value obtained by dividing the mass of Pb ₃ O _{4 by} the mass of the fired product by 100.

The lead oxidation rate, that is, the content (% by mass) of Pb ₃ O ₄ in the fired product can be quantified by the following titration operation.
First, an acetic acid-ammonium acetate solution and a 0.1N sodium thiosulfate solution are added to a measurement sample and stirred to be completely dissolved.
Next, a starch solution is added to this sample solution, and a 0.1N iodine solution is dropped, and the sodium thiosulfate ions remaining in the solution are taken as the end point when a purple color is exhibited by the iodine starch reaction. Titrate. A blank experiment is performed in the same manner, and the Pb ₃ O ₄ content (% by mass) is calculated from the amount of the iodine solution used for the titration using the following formula.
Pb ₃ O ₄ content (% by mass) = [0.3428 × (b′−b) × f] / S × 100
b ′: Amount of iodine solution consumed during titration in the blank experiment (ml)
b: Amount of iodine solution consumed for titration of sample (ml)
f: Factor of iodine solution S: Amount of sample (g)

In the present invention, a lead lead having a lead lead conversion rate of 30% by mass or more and 80% by mass or less is used as the low lead oxidation rate. This is because the use of lead tans having a low lead tanning rate in the above range can suppress softening of the active material without reducing the initial capacity of the battery even when an antimony compound is used in combination. .
Although details of the reason why the softening of the active material can be suppressed without reducing the initial capacity of the battery in the present invention are unknown, it is considered as follows.

When a lead tanning rate of 30 to 80% by weight is added to the cathode active material raw material, antimony atoms are incorporated into the active material crystal, thereby reducing the amount of lead tanning. Promotes the bond between conversion rate lead and lead powder (PbO), and a strong network is formed. As a result, the discharge distribution of the active material is improved, and the utilization factor of the active material is improved. Therefore, it is considered that the initial capacity did not decrease.
In addition, it is considered that the softening of the active material is suppressed because the strong conductive network formed by the incorporation of antimony atoms into the active material crystal delays the bond reduction (softening) of the active material due to charge and discharge.

  By the way, the said patent document 1 describes that an initial operating characteristic will improve, if the addition amount of a general lead tan (high lead tan formation rate lead tan of 98 mass% or more) increases. . From this, it is considered that the initial capacity is improved by using a lead having a high lead oxidation rate than using a lead having a low lead oxidation rate in a battery having no antimony compound added and adding a red lead. Then, even when an antimony compound and a red lead are added, it is estimated that the initial capacity is improved by adding a red lead having a high lead oxidation rate than adding a red lead having a low lead oxidation rate.

  However, as a result of studies by the present inventors, in a battery using an antimony compound and a lead tan having a lead oxidation rate of 30% by mass or more and 80% by mass or less, the antimony compound and a high lead saponification having a lead oxidation rate of 98% by mass or more are obtained. Since the initial capacity was higher than the battery using the lead conversion rate, and the knowledge that the effect of suppressing the softening of the active material was higher than the battery using the high lead formation rate lead was obtained. is there.

Although the details of the reason for obtaining the above knowledge are unknown, it is considered as follows.
A low lead tanning rate lead tan with a lead tanning rate of 30% by mass or more and 80% by mass or less contains more PbO that plays an important role in bonding between positive electrode active material particles than a high lead tanning rate. Yes. When this low lead oxidation rate lead oxide and antimony compound are added to the cathode active material raw material, antimony atoms are incorporated into the active material crystal, thereby promoting the bonding between the low lead oxidation rate lead oxide and lead powder. A strong network is formed. When this network is formed, as described above, the discharge distribution of the active material becomes good, and the utilization factor of the active material is improved, so that an initial capacity higher than that of a battery using a high lead tantalum conversion rate is obtained. It is thought. In addition, the strong conductive network formed by the incorporation of antimony atoms into the active material crystal delays the softening of the active material due to charge and discharge, and thus the effect of suppressing the softening of the active material is considered to have increased.

  On the other hand, when a red lead having a lead oxidation rate higher than 80% by mass is used, the proportion of the red lead having a weak binding force with the lead powder increases. However, a strong network is not formed. As a result, softening of the active material is likely to occur, and the initial capacity is not improved more than that using a lead tan having a lead tan rate of 30% by mass to 80% by mass.

  In addition, when a lead tanning rate uses a lead tan with a lead tanning rate of less than 30% by mass, the proportion of PbO having a strong binding force with lead powder increases, and antimony atoms are incorporated into the active material crystal. This makes it difficult to form a strong conductive network. As a result, softening of the active material is likely to occur, and the initial capacity is not improved more than that using a lead tan having a lead tan rate of 30% by mass to 80% by mass.

Examples of the antimony compound used in the present invention include Sb ₂ O ₃ and Sb ₂ (SO ₄ ) ₃ .
In the present invention, when the antimony compound is added at a ratio of 0.01 parts by mass or more and 0.2 parts by mass or less as the amount of antimony atoms with respect to 100 parts by mass of the positive electrode active material in terms of PbO ₂ , an initial capacity is obtained. Is significantly improved and the effect of suppressing softening of the active material is enhanced, which is preferable.

Next, the manufacturing method of the lead acid battery of this invention is demonstrated concretely.
First, a positive electrode plate is prepared using lead powder, a lead tanning rate of 30% by mass to 80% by mass, and an antimony compound as a positive electrode active material material. Specifically, lead powder and low lead tanning rate are mixed, antimony compound and reinforcing material such as acrylic fiber are mixed, water and sulfuric acid are added and kneaded, and positive electrode active material paste After filling this positive electrode active material paste into a lead alloy lattice, it is aged and dried to produce an unformed positive electrode plate.

  Next, the positive electrode plate and the negative electrode plate produced by a conventional method are alternately combined through a separator to produce an unformed electrode plate group. Next, after the unformed electrode plate group is inserted into the battery case, the electrode plate group is welded, the cells are connected, the lid is bonded, the terminal is welded, and the assembly is completed. By forming the tank, the lead storage battery of the present invention is obtained.

<Example>
Examples to which the present invention is specifically applied will be described below.
(1) Production of positive electrode plate for lead-acid battery Lead powder and lead powder produced by ball milling are mixed at 420 ° C until a predetermined lead tanning rate is reached. Mixed raw materials were prepared.
To this lead powder / lead oxide mixed raw material, 0.3% by mass of acrylic fiber and a predetermined amount of antimony compound [Sb ₂ O ₃ or Sb ₂ (SO _{4 3} ) was dry-mixed, and a predetermined amount of water and dilute sulfuric acid were added and kneaded to prepare a positive electrode active material paste. This positive electrode active material paste was filled in an expanded lattice made of a Pb-0.07% Ca-1.5% Sn alloy, and then aged and dried to produce an unformed positive electrode plate. Here, the mass of the positive electrode paste filled in the expanded lattice is measured (measurement value A).

  For comparison, a positive electrode plate (test No. 1) to which no antimony compound and red lead are added, and a positive electrode to which high lead lead conversion rate lead (b) having a lead lead conversion rate of 98% by mass or more is added without adding an antimony compound. Plate (Test No. 2), positive electrode plate with no antimony compound added and added with 50% by weight of lead tanning (Test No. 3), positive electrode plate with no antimony added and antimony compound added (Test No.) 4) The positive electrode plate (test number 5) which added the high lead tanning rate lead tan (b) and the antimony compound was produced.

  In addition, the kind of lead tan used when making the positive electrode plate, the lead tanning rate, the blending ratio of lead powder and lead oxide (lead tan) in the lead powder / lead oxide mixed raw material, the kind and addition of antimony compounds Details such as the amount are shown in each example group.

(2) Production of negative electrode plate Lignin, carbon, barium compound and acrylic fiber were dry-mixed with lead powder, and a predetermined amount of water and dilute sulfuric acid were added and kneaded to prepare a negative electrode active material paste. This negative electrode active material paste was filled in an expanded lattice made of a Pb-0.05% Ca-0.5% Sn alloy, and then aged and dried to produce an unformed negative electrode plate.

(3) Production of battery The polyethylene resin separator produced by the extrusion molding method was folded in half, and both sides were sealed with a mechanical seal to produce a bag-like separator. The unformed negative electrode plate produced in (2) Stowed.
After inserting the unformed electrode plate group obtained by alternately laminating 4 unformed positive electrode plates prepared in (1) and 5 unformed negative electrode plates housed in a bag-shaped separator into the battery case, After the cells were connected by welding, a lid was welded to produce an unformed battery.
Dilute sulfuric acid having a specific gravity of 1.230 (20 ° C.) was poured into the non-chemical battery, and the battery was formed in a 25 ° C. water tank and formed into a 38B19 size lead storage battery (nominal voltage: 12V, specified in JIS D 5301). Rated capacity: 28 Ah) was produced.

<Battery performance evaluation test>
About the battery produced by said method, the battery performance test was done in the following procedures.
(1) Initial capacity test (reserved capacity)
In accordance with JIS D 5301, each battery was measured in a water bath at 25 ° C. with a discharge current of 25 A until a discharge end voltage of 10.5 V was reached.
The test results for each battery are shown in Tables 1 to 3 as initial capacity ratios when the initial capacity test result of the battery having the positive electrode plate of test number 1 (Comparative Example 1) is 100. The larger the initial capacity ratio is, the higher the initial capacity is. If the initial capacity ratio is 100 or more and 105 or less, it is determined that the initial capacity has not decreased, and if the initial capacity ratio is 106 or more, the initial capacity is determined to be improved. , 110 or more, it was determined that the initial capacity was significantly improved.

(2) Life performance test In accordance with JIS D 5301, the battery is discharged for 4 minutes at a discharge current of 25 A in a water bath at a temperature of 75 ° C. and charged for 10 minutes at a charge voltage of 14.8 V and a charge limiting current of 25 A. This was regarded as one cycle, and a 960 cycle repeated life test was conducted.
The positive electrode plate was taken out from the battery after the life test, washed with water and dried, and the electrode plate mass (lattice + residual active material) was measured (measurement value B).

Next, the residual active material was removed from the electrode plate, and the mass of the lattice was measured (measured value C).
The amount of active material falling off is calculated from the following formula (1), and the ratio (referred to as the degree of softening of the active material) when the amount of active material falling off of the battery (Comparative Example 1) provided with the positive electrode plate of test number 1 is taken as 100. As shown in Tables 1 to 3. The smaller the degree of softening of the active material, the higher the effect of suppressing the softening of the active material.
Active material shedding amount = (A × 0.9) − (B−C) (1)
In formula (1), A, B, and C mean measured value A, measured value B, and measured value C, respectively.
Here, A is multiplied by 0.9 because the amount of the active material becomes about 0.9 times the amount of the positive electrode paste at the time of filling through the chemical conversion step.

<Example group 1>
Investigate the effect of antimony compound addition, red lead (high and low lead oxidation), and the type of lead added on initial capacity and life performance Therefore, the batteries of Comparative Examples 1 to 5 below and the battery of Example 1 were manufactured and subjected to an evaluation test.

Comparative Example 1: Battery provided with a positive electrode plate (Test No. 1) to which neither an antimony compound nor a red lead is added. Comparative Example 2: a high lead red lead rate of 98% by mass or higher without adding an antimony compound. Battery provided with positive electrode plate (test number 2) to which b) was added Comparative example 3: Battery provided with positive electrode plate (test number 3) to which a lead tanning rate of 50 mass% was added without adding an antimony compound Comparative example 4: Battery provided with a positive electrode plate (Test No. 4) to which an antimony compound was added without adding a red lead Comparative Example 5: Positive electrode plate (Test No. 5) to which a high lead tantalization rate lead lead (b) and an antimony compound were added Example 1: A battery provided with a positive electrode plate (test number 6) to which a lead tanning rate of 50% by mass and an antimony compound were added.

  In this example group, lead powder and lead oxide [(b) lead dan (high lead tan) or (B) low lead tan) are mixed at the ratio shown in Table 1. Thus, a mixed powder of lead powder and lead oxide was prepared. Table 1 shows lead powder and lead oxide [(b) lead tan (high lead tanning ratio lead tan) relative to the total mass of lead powder and lead oxide (mass of lead powder / lead oxide mixed raw material). ) Or (B) low lead oxidation rate of lead] is shown as a percentage (mass%).

Further, in this embodiment groups, when preparation of the positive electrode plate of Test No. 4-6, using Sb ₂ O ₃ as the antimony compound. The amount of Sb ₂ O ₃ used was 0.05 parts by mass in terms of antimony atoms with respect to 100 parts by mass obtained assuming that all of the lead powder / lead oxide mixed raw material was oxidized to PbO ₂ . .
Table 1 also shows the lead tanning rate of the (B) lead tanning rate used in the production of the positive electrode plate and the results of the evaluation test.

  As is apparent from Table 1, the battery of the present invention comprising a positive electrode plate prepared by mixing a lead tanning rate of 50 mass% with a lead tanning rate and an antimony compound in a positive electrode active material material (Example) In 1), an initial capacity ratio of 110 and an active material softening degree of 95 were obtained. That is, in the battery of Example 1, the initial capacity was remarkably improved and the effect of suppressing the softening of the active material was high.

Although details of the reason why such a result was obtained are unknown, it is considered as follows.
The low lead oxidation rate red lead used in Example 1 contains more metals Pb and PbO that play an important role in the bonding between the positive electrode active material particles than the high lead oxidation rate lead red. When this low lead oxidation rate lead oxide and antimony compound are added to the cathode active material raw material, antimony atoms are incorporated into the active material crystal, thereby promoting the bonding between the low lead oxidation rate lead oxide and lead powder. A strong network is formed. As a result, in the battery of Example 1, the discharge distribution of the active material was improved, the utilization factor of the active material was improved, and the initial capacity was considered to be significantly improved.

  Further, in the battery of Example 1, antimony atoms are incorporated into the active material crystal to promote the bonding between the low lead tanning rate and the lead powder, thereby forming a strong network. Since it delays the decrease (softening) of the active material due to charge / discharge, it is considered that the effect of suppressing the softening of the active material was high.

  In the same manner as in Example 1, a red lead and an antimony compound were added. However, in the battery of Comparative Example 5 using a high red lead rate of red lead as a red lead, Comparative Example 1 in which no red lead and no antimony compound were added. Although the initial capacity was higher than that of the battery of Example 1, the initial capacity was not significantly improved as compared with the battery of Example 1.

  This is because, in the high lead oxidation rate used in Comparative Example 5, the proportion of the red lead having a weak binding force with the lead powder (PbO) increases, so the bond between the lead lead and the lead powder possessed by the antimony atom. Even if it has the effect of promoting the above, since a strong network is not formed, it is considered that the remarkable initial capacity improvement effect was not obtained as in Example 1.

  In the battery of Comparative Example 5, the softening degree of the active material was large. In Comparative Example 5, since a high lead tanning rate is used, the bond between the active material particles is weakened, and it is considered that the softening of the active material is likely to occur due to repeated charge and discharge.

  Furthermore, in a battery (Comparative Example 2 and Comparative Example 3) provided with a positive electrode plate to which a red lead (a high lead tan or red lead tan) was added without adding an antimony compound, Both the initial capacity ratio and the softening degree of the active material were larger than those of the battery of Comparative Example 1 to which no antimony compound was added. From this result, it was found that, when only the lead tan was added, the initial capacity was improved but the effect of suppressing the softening of the active material was lower than that without the tan.

  On the other hand, in the battery (Comparative Example 4) including the positive electrode plate to which only the antimony compound was added, the softening degree of the active material was smaller than that of the battery of Comparative Example 1 to which no lead oxide and antimony compound were added, but the initial capacity ratio was small. . From this result, it was found that when only the antimony compound was added, the effect of suppressing the softening of the active material was high, but the initial capacity was reduced.

<Example group 2>
In order to investigate the effects of the lead tanning rate and the low lead tanning rate on the initial capacity and life performance, A positive electrode plate mixed at a ratio was prepared, and an evaluation test was conducted in the same manner as in Example Group 1.

In this example group, the lead powder and the low lead tanning rate lead tan are selected so that the total amount of lead tan relative to the mass of the lead powder / lead oxide mixed raw material is 10% by mass, 5% by mass, and 20% by mass. Were mixed.
Specifically, a lead tanning rate of 20% by mass, 30% by mass, 40% by mass, 50% by mass, 60% by mass, 70% by mass, 80% by mass, 90% by mass, A lead powder and a lead oxide mixed lead material were mixed at a ratio shown in Table 2 to produce a lead powder / lead oxide mixed raw material. In addition, in Table 2, the combination of lead powder and lead oxide [(B) low lead tanning ratio lead tan] to the total mass of lead powder and lead oxide (mass of lead powder / lead oxide mixed raw material) The ratio was shown in percentage (mass%).

Moreover, in the present Example group, 0.05 mass in terms of antimony atoms was converted to 100 mass parts of the lead powder / lead oxide mixed raw material converted to PbO ₂ as the antimony compound in producing the positive plates of test numbers 7 to 29. Part of Sb ₂ O ₃ was used.

  In Table 2, (B) the lead tanning rate of the low lead tanning rate used in the production of the positive electrode plate, the total amount of lead tanning (mass%) relative to the mass of the lead powder / lead oxide mixed raw material, and The results of the evaluation test are also shown, and the results of the evaluation test of the battery of Example 1 manufactured in Example Group 1 and the battery of Comparative Example 1 are also shown.

As apparent from Table 2, in the batteries (Examples 1 to 18) having a lead tanning rate of 30% by mass or more and 80% by mass or less, the softening degree of the active material was 100 or less regardless of the total amount of lead tan. . On the other hand, a battery (Comparative Examples 6, 8, and 10) including a positive electrode plate to which a lead tanning rate of 20% by mass is added, and a low tanning rate of 90% by mass. In the battery (Comparative Examples 7, 9, and 11) including the positive electrode plate to which the rate of red lead was added, the active material softening degree was 110 or more.
From this result, in the battery of the present invention produced using a lead tan having a lead tanning rate of 30% by mass or more and 80% by mass or less, the active material is softened more than the battery using the red tan outside the scope of the present invention. It was found that the suppression effect is high.

Moreover, the initial capacity ratios of the batteries prepared in this example group (Comparative Examples 6 to 11 and Examples 2 to 18) and the battery of Example 1 were 102 or more. From this result, it was found that the initial capacity does not decrease in a battery to which an antimony compound and a lead oxide having a lead oxidation rate of 20 to 90% by mass are added.
Among these, in each battery of Examples 6-8, Examples 10-12, and Comparative Examples 7 and 10, the initial capacity is improved, Examples 1 to 5, Example 9, Examples 13 to 18, and Comparative Examples. It was found that the initial capacity was remarkably improved in each of the 11 batteries.

When comparing the initial capacity ratios of batteries (for example, Comparative Example 6, Examples 1 to 6, and Comparative Example 7) provided with positive electrode plates having the same total amount of lead, a battery using a lead having a lead tanning rate of 20% by mass. The initial capacity ratio of the battery is smaller than the initial capacity ratio of the battery using the lead tanning rate of 30% by mass to 80% by mass, and the initial stage of the battery using the lead tanning rate of 90% by mass of the lead tanning rate. The capacity ratio was equal to or less than the initial capacity ratio of a battery using a lead tan having a lead tan rate of 30% by mass to 80% by mass.
That is, in a battery having the same total lead content, in a battery using a red lead having a lead oxidation rate of 30% by mass or more and 80% by mass or less, a battery using a red lead having a lead oxidation rate of 20% by mass and lead It was found that an initial capacity higher than that of a battery using a lead tan having a tanning ratio of 90% by mass can be obtained, and the active material softening degree is small as described above, which is preferable.

<Example group 3>
In order to investigate the effect of the type and amount of the antimony compound on the initial capacity and life performance, positive electrode plates in which two types of antimony compounds were mixed at various ratios were prepared, and an evaluation test was conducted in the same manner as in Example Group 1. It was.

  In this example group, the ratio of the lead powder is 80% by mass and the ratio of the low lead tanning rate of 50% by mass is 50% by mass with respect to the mass of the lead powder / lead oxide mixed raw material. A lead powder / lead oxide mixed raw material was prepared by mixing so as to be mass%. In addition, in Table 3, the combination of lead powder and lead oxide [(B) low lead tanning rate lead tan] to the total mass of lead powder and lead oxide (mass of lead powder / lead oxide mixed raw material) The amount was expressed as a percentage (mass%).

Further, in this embodiment groups, positive Upon preparation of the electrode plate, 0.005 parts by antimony atom relative to PbO _2-converted lead powder, lead oxide mixed feed 100 parts by weight of antimony compounds of test numbers 30 to 35 ˜0.3 parts by mass of Sb ₂ O ₃ was used. In producing the positive plates of test numbers 36 to 40, 0.005 parts by mass to 0.3 parts by mass of Sb ₂ as antimony atoms with respect to 100 parts by mass of the lead powder / lead oxide mixed raw material converted to PbO ₂ as the antimony compound. (SO ₄ ) ₃ was used (see Table 3 for the amount of antimony compound added).

Table 3 shows the lead tanning rate of (B) lead tanning rate used in the production of the positive electrode plate, the type and addition amount of the antimony compound, and the results of the evaluation test. 1 also shows the results of evaluation tests of the battery of Example 1, the battery of Comparative Example 1, and the battery of Comparative Example 3 prepared in 1. The Sb compound addition amount (parts) in Table 3 means the addition amount (parts by mass) as antimony atoms with respect to 100 parts by mass of the lead powder / lead oxide mixed raw material converted to PbO ₂ .

  As is apparent from Table 3, in the battery of Example 1 and the batteries of Examples 19 to 29 in which the lead tanning rate was 50% by mass and the antimony compound was added, the initial capacity ratio Was 106 or more, and the initial capacity was improved.

In particular, a battery in which an antimony compound was added at a ratio of 0.01 parts by mass or more and 0.2 parts by mass or less as an amount of antimony atoms with respect to 100 parts by mass of lead powder / lead oxide mixed raw material converted to PbO ₂ (Example) 1, Examples 20 to 23 and Examples 26 to 28) had an initial capacity ratio of 110 or more, and the initial capacity was significantly improved.

  Moreover, in the battery (Example 1, Examples 20-23, Examples 26-28) which added the antimony compound in the ratio of 0.01 mass part or more and 0.2 mass part or less as the quantity of the antimony atom, active material softening degree Was 100 or less, and the effect of suppressing softening of the active material was high.

From these results, in the present invention, the addition amount of the antimony compound is 100 parts by mass of the mass of the lead powder / lead oxide mixed raw material converted to PbO ₂ (the total mass of the lead powder and the low lead tanning rate). It was found that the amount of antimony atoms is preferably 0.01 parts by mass or more and 0.2 parts by mass or less.

  In addition, the active material softening degree of the battery (Example 19, Example 25) in which the addition amount of the antimony compound is 0.005 parts by mass is smaller as the batteries of Example 1, Examples 20 to 23, and Example 28. Although it was not, it was smaller than the battery of the comparative example 3 which did not add an antimony compound and added 20 mass% of lead tan with 50 mass% of lead tanning. From this, it was found that the addition of even a very small amount of the antimony compound has a higher effect of suppressing the softening of the active material than the battery in which the antimony compound is not added and lead is added.

<Other embodiments>
The present invention is not limited to the embodiments described with reference to the above description and drawings. For example, the following embodiments are also included in the technical scope of the present invention.
In the above-described embodiment, the lead powder used is one obtained by firing the lead powder produced by the ball mill method at 420 ° C. until the predetermined lead tanning rate is reached, but the lead powder produced by another method such as the Barton method is used. It may be fired.

Claims (2)

Featuring a positive electrode plate made of a positive electrode active material containing lead powder, a low lead tanning rate of 30 to 80% by weight, and an antimony compound. Lead storage battery. The antimony compound is added in a proportion of 0.01 parts by mass or more and 0.2 parts by mass or less as an amount of antimony atoms with respect to 100 parts by mass of the positive electrode active material in terms of PbO _2. The lead acid battery according to 1.