JP4904686B2 - Lead acid battery - Google Patents

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, idle stop vehicles that stop the engine while the vehicle is temporarily stopped, and regenerative braking systems that convert the vehicle's kinetic energy into electrical energy and store this electrical energy when the vehicle decelerates are put into practical use. ing.

  For example, in a vehicle equipped with an idle stop system, the lead storage battery is not charged during idle stop. On the other hand, in order to supply electric power to the on-board equipment, the SOC is inevitably lower than that of a conventional lead-acid battery for starting a vehicle. Further, in a vehicle equipped with a regenerative brake system, it is necessary to control the SOC of the lead storage battery to be lower and about 50 to 90% in order to store electric energy during regeneration.

  Moreover, in any system, charging / discharging is repeated more frequently than before. Moreover, not only charging / discharging is performed at a low SOC, but also due to an increase in dark current accompanying the electrification of vehicle parts, lead-acid batteries discharge during a long-term stop, resulting in overdischarge. It is coming.

  Therefore, in order to adapt to a vehicle equipped with these systems, the lead storage battery used in this system is required to have a life characteristic when charging and discharging are frequently repeated in a region where the SOC is lower. The main cause of deterioration of the lead storage battery in such a use mode is insufficient charge due to a decrease in charge acceptance of the lead storage battery.

  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 shows that a lead alloy layer containing tin and antimony is formed on the surface of the 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. The antimony deposited on the negative electrode active material has the effect of lowering the charging voltage and improving the charge acceptability of the lead storage battery by preciously shifting the charging potential of the negative electrode. As a result, insufficient charging during the charge / discharge cycle 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, when mounted on an idle stop vehicle as described above or a vehicle equipped with a regenerative braking system, that is, when used in a usage environment with a higher charge / discharge frequency in a region where the SOC is low, In the lead storage battery having only the configuration as in 1, the charge acceptability can be secured, but there has been a problem that the corrosion proceeds at the negative electrode grid ear. As a result, the thickness of the negative electrode lattice lugs was reduced, the current collection efficiency in the negative electrode was lowered, and the life was shortened.

  Moreover, the decrease in the thickness of the negative electrode grid ears causes a decrease in the strength of the negative electrode grid ears as well as a decrease in current collection efficiency. In particular, since a battery mounted on a vehicle is constantly subjected to vibration and impact while the vehicle is running, the negative electrode lattice ear may be deformed to cause a displacement of the negative electrode plate, thereby causing an internal short circuit with the positive electrode plate.

  Conventionally, regarding the corrosion of the negative electrode grid ear, the negative electrode shelf and the negative electrode grid ear are exposed from the electrolyte and exposed to oxygen in the atmosphere, so that the welded portion between the negative electrode shelf and the negative electrode grid ear is corroded and disconnected. It was known. However, even when the negative electrode shelf and the negative electrode grid ear are immersed in the electrolyte, Sb contained in the lead alloy connection member such as Sb arranged on the positive electrode lattice or the positive electrode shelf, the positive electrode column, and the positive electrode connector is electrolyzed. It has been found that the negative electrode lattice ear is corroded by being eluted into the liquid and deposited in a small amount on the surface of the negative electrode lattice ear.

In Patent Document 2, the positive electrode grid, the positive electrode connection member, the negative electrode grid ear, and the negative electrode connection member are made of Pb or Pb alloy that does not contain Sb, and either the negative electrode lattice bone or the negative electrode active material affects the amount of liquid reduction. A lead storage battery containing a small amount of Sb is not proposed. With such a configuration, the elution of Sb from the positive electrode and the precipitation of Sb on the negative electrode lattice ear are suppressed, and by including Sb in the negative electrode active material, the charge acceptability and deep discharge life of the battery are improved to some extent. It has been shown.
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 lattice ears and the negative electrode lattice ear corrosion caused thereby. However, in a use mode in which the battery is overdischarged or the charge / discharge is frequently repeated in a low SOC region, Sb in the negative electrode active material is re-eluted into the electrolyte solution and deposited in the negative electrode lattice ear. It has been found that the lattice ears are corroded.

  The present invention drastically improves the life characteristics by improving the charge acceptance of the lead storage battery in the use mode as described above, and the negative electrode even when the overdischarge and the SOC are repeated in a low SOC region. Lead that is suitable for highly reliable idle-stop cars, charging control systems, cars with regenerative braking systems, etc., by preventing antimony migration to the grid ears and suppressing corrosion at the negative grid ears An object is to provide a storage 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. Comprises Sb voltage as low material 0.0002 wt% to 0.007 wt%, and a synthetic resin sheet containing silica 40 wt% to 85 wt%, or a fiber mat containing silica from 10 to 40 wt% as a separator The lead acid battery characterized by having provided is shown.

Further, the invention according to claim 2 of the present invention, in the lead acid battery of claim 1, is characterized in that the Sb concentration of the negative electrode active material and from 0.0004 to 0.006 wt%.

  According to the lead storage battery of the present invention, the life characteristics are dramatically improved by improving the charge acceptance in an environment where overdischarge or charge / discharge is repeated more frequently in a region where the SOC is relatively low. While improving and suppressing the corrosion in a negative electrode grating | lattice ear | edge, the long life lead storage battery with high reliability can be obtained.

  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.

  In the lead storage battery 1 of the present invention, a predetermined number of separators 4, a positive electrode plate 2 and a negative electrode plate 3 are combined, and the same polarity ears of the positive electrode grid ear 22 and the negative electrode grid ear 32 are collectively welded to the positive electrode shelf 5 and the negative electrode respectively. A shelf 6 is formed. A positive pole 7 or a positive electrode connection body (not shown) is formed on the positive electrode shelf 5, and a negative electrode connection body 8 or a negative electrode pillar (not shown) is formed on the negative electrode shelf 6. In the example shown in FIG. 1, an example is shown in which the positive electrode column 5 is provided on the positive electrode shelf 5, and the negative electrode connector 8 is provided on the negative electrode shelf 6. The connection body and the negative electrode column 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 first end cell from the positive electrode terminal side. The negative pole connecting body 8 is connected to the negative pole shelf 6. In the electrode plate group constituting the sixth end cell from the positive electrode terminal side, the positive electrode connector is connected to the positive electrode shelf 5, and the negative electrode pole column is connected to the negative electrode shelf 6. And the electrode group which comprises the intermediate | middle cell located between these end cells takes the structure by which the connection body of the positive electrode and the negative electrode was connected to the positive electrode shelf 5 and the negative electrode shelf 6, respectively.

  In the present invention, the positive electrode shelf 5, the positive electrode column 7, and / or the positive electrode connecting member 9 and the positive electrode lattice 21 configured by the positive electrode connecting body are configured by 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. Further, since the oxidation resistance is not required for the negative electrode as compared with the positive electrode, pure Pb can 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-described composition, in order to suppress the disappearance of Ca from the molten lead alloy, the addition of about 0.001 to 0.05% by mass of Al is inevitable. The presence of about 0.0005 to 0.005 mass% Bi as an impurity does not impair the effects of the present invention 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. The substance having a hydrogen overvoltage lower than that of Pb is Sb or a compound thereof (antimony oxide, sulfate, antimonate, etc.) . The Sb-containing concentration in the negative electrode active material is 0.0002 mass% to 0.007 mass%, more preferably 0.0004 to 0.006 mass% .

  The addition of Sb to the negative electrode active material may be performed by adding Sb or a material containing Sb as described above to the negative electrode active material paste. Further, instead of directly adding Sb or an Sb compound into the negative electrode active material, the negative electrode plate is immersed in an electrolyte containing Sb ions, for example, a dilute sulfuric acid electrolyte containing antimony sulfate or antimonate, and by electroplating, Sb can also be electrodeposited on the negative electrode active material.

  By adding Sb to the negative electrode active material, 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 Sb concentration is 0.0004 mass% or more. On the other hand, in the region where the Sb content concentration exceeds 0.006% by mass, the corrosion of the negative electrode lattice 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, what contains a silica is used as a separator which isolates a positive electrode and a negative electrode. As this separator, a synthetic resin sheet such as polyethylene containing silica can be used. When using the separator of a polyethylene resin sheet, it is preferable that the content concentration (silica mass x 100 / mass of polyethylene resin sheet containing silica) in the silica separator is 40 mass% to 85 mass%.

  Moreover, it can replace with the above-mentioned polyethylene resin sheet and can use fiber mats, such as a glass fiber mat containing a silica. When using a glass fiber mat, it is preferable that the silica content density | concentration (silica mass x100 / fiber mat mass containing a silica) in a glass fiber mat shall be 10-40 mass%. As silica, porous silica having pores with an average pore diameter of 20 μm or less can be used.

  The lead storage battery of the present invention is obtained by assembling a lead storage battery in which the electrode group is immersed in an electrolytic solution according to a conventional method, using the above electrode group. In the present invention, since the negative electrode active material includes a material having a hydrogen overvoltage lower than Pb, such as Sb, it is not applied to a control valve type lead-acid battery. When applied to a control valve type lead storage battery, the internal pressure of the battery increases due to the generation of a small amount of gas, and the control valve is opened for a long time. As a result, air flows into the battery and the negative electrode is oxidized.

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

  On the other hand, even when Sb is eluted from the negative electrode active material by over-discharging the lead storage battery or by frequently repeating charge and discharge in the low SOC region, this silica adsorbs Sb, so that the Sb negative electrode lattice ear And the corrosion of the negative electrode lattice ear due to this can be suppressed.

When the content concentration of silica described above is 40% by mass or less in the separator of the polyethylene resin sheet and 10% by mass or less in the separator of the glass fiber mat, the negative electrode lattice ear corrosion inhibitory effect of the present invention is slightly reduced. The silica concentration is preferably 40% by mass or more and 10% by mass or more, respectively. Further, in order to further adsorb Sb to the silica surface, as the silica (SiO ₂₎ using, it is preferable to use the (200m ² / g, for example) having a large specific surface area by having a porosity.

  On the other hand, when the silica content in the separator of the polyethylene resin sheet exceeds 85% by mass, the separator becomes fragile, easily cracks or perforates, and easily causes an internal short circuit of the battery. In the sheet separator, the silica concentration is preferably 85% by mass or less.

  Further, when the silica content concentration exceeds 40 mass% in the separator of the glass fiber mat, the separator strength decreases or the battery internal resistance increases due to a decrease in the bonding strength between the glass fibers, and the discharge voltage characteristics of the battery Decreases. Therefore, the silica concentration in the glass fiber mat is preferably 40% by mass or less.

  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 base material. 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, when 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.

  By preparing lead storage battery members such as the following positive electrode plate, negative electrode plate, separator, alloy for connecting member, etc., by combining these members, a battery according to the present invention example and a comparative example is prepared, and a life test is performed to prepare the negative electrode Evaluation of lattice ear corrosion and battery life characteristics was performed.

(1) Positive electrode plate 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 slab was rolled in stages to form an alloy sheet, which was then expanded to form a positive grid. 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. When Sb quantitative analysis contained in a positive electrode active material was performed, Sb density | concentration was less than the detection limit (0.0001 mass%).

(2) Negative Electrode Plate After rolling a slab of Pb-0.07 mass% Ca-0.25 mass% Sn alloy, an expansion process was performed to create a negative electrode lattice. In addition, when Sb quantitative analysis contained in this negative 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), 0.0002, respectively. Negative electrode plates with mass%, 0.0004 mass%, 0.006 mass%, and 0.007 mass% were prepared.

  In this example, natural lignin (Vanilex N manufactured by Nippon Paper Chemicals Co., Ltd.) was used as the expander. Co., Ltd. Vispers P215) may be used.

(3) Separator-Separator made of synthetic resin sheet As a separator made of synthetic resin sheet (hereinafter referred to as separator A), a polyethylene sheet having a maximum pore diameter of 10 to 50 µm and having a thickness of 0.3 mm or less is folded in a U-shape. And the both sides were heat-sealed and the bag-shaped separator which only the upper part opened was produced. The silica-containing concentration in the separator A was 0% by mass, 35% by mass, 40% by mass, 65% by mass, and 85% by mass. As the silica, a porous one having pores with an average pore diameter of 20 μm or less was used.

Fiber Separator Separator A fiber mat separator (hereinafter referred to as Separator B) having silica supported in a glass fiber mat was used. The silica-containing concentration contained in the separator B was 0% by mass, 5% by mass, 10% by mass, 40% by mass, and 50% by mass. As the silica, a porous one having pores with an average pore diameter of 20 μm or less was used.

(4) Lead alloy for positive electrode connection member and alloy for negative electrode connection member As an alloy 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
The positive electrode plate, the negative electrode plate, and the separator A are used in the combinations shown in Tables 1 and 2, and the combinations shown in Tables 1 and 2 are used. The electrode is composed of 5 positive plates and 6 negative plates per cell. A liquid type 55D23 type starting lead-acid battery (12V48Ah) having a plate group and having all electrode plates immersed in an electrolytic solution was produced. In addition, it was set as the structure which accommodated the negative electrode plate in the bag-shaped separator A. FIG.

  Each battery shown in Table 1 and Table 2 was subjected to a cycle life test after overdischarge. The test conditions were as follows. First, in a 25 ° C. atmosphere, the test battery is discharged at a constant current of 10 A until the battery voltage reaches 10.5V. Thereafter, a 12 W light bulb was connected between the battery terminals and left for 48 hours to overdischarge the test battery. Thereafter, the test battery was charged at a constant voltage of 14.5 V (maximum current 25 A) for 8 hours to perform a cycle life test.

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 is reduced to 7.0 V every 7200 cycles of charge / discharge is defined as the life cycle number. Normally, a light load life test defined in JIS D5301 for a start-up lead-acid battery is composed of a cycle of 25 A discharge for 4 minutes and a constant current charge of 10 minutes with a maximum current of 25 A. The test conditions were such that charging and discharging were frequently performed in a state where the SOC was lower than in the load life test.

The calculation method of the life cycle number was 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. In addition, the negative electrode lattice ear cross-sectional area in the initial state before the test is S, the negative electrode lattice 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 Ear corrosion rate. The cross-sectional area of the negative electrode grid ear in the initial state before the test is (width) 13.0 mm × (thickness) 0.7 mm = 9.1 mm ^{2. When} the ear corrosion rate is 50%, the cross-sectional area is 4. This corresponds to a reduction of 55 mm ² .

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

  From the results shown in Table 4, for the battery using a lead alloy containing Sb (alloy B: Pb-2.5 mass% Sb) for the positive electrode and negative electrode connecting members, the negative electrode grid ear corrosion is remarkable. Then, due to the significant decrease in the cross-sectional area of the negative electrode grid ears, the discharge voltage was remarkably lowered, and the life was completed after 20000 to 30000 cycles. This is considered to be because Sb contained in the connecting member on the positive electrode side or the negative electrode side elutes in the electrolytic solution and re-deposits on the negative electrode lattice ear. When these test batteries were disassembled and quantitative analysis of Sb in the negative electrode lattice ear was performed, the presence of about 0.0006 mass% Sb in the negative electrode lattice ear was confirmed.

  From the results shown in Table 3, a lead alloy containing no Sb (alloy A: Pb-2.5 mass% Sn) was used for the positive electrode and negative electrode connecting members, and in the battery containing Sb in the negative electrode active material, polyethylene was used. In the separator A made of a resin sheet, the battery of the present invention example including silica has a very good life cycle number while suppressing the negative electrode grid ear corrosion as compared with the batteries of other comparative examples. . The effect of improving the life characteristics is considered to be due to the improvement in charge acceptance of the negative electrode plate by Sb in the negative electrode active material. In addition, when these test batteries were disassembled and quantitative analysis of Sb in the negative electrode lattice ear was performed, Sb in an amount exceeding the detection limit (0.0001 mass%) could not be detected from the negative electrode lattice ear.

  On the other hand, it can be presumed that the negative electrode lattice lug suppressing effect of the present invention is obtained by capturing Sb ions eluted in the electrolyte solution in silica contained in the separator. As a result of the trapping of Sb ions by silica, it can be assumed that diffusion of Sb ions to the vicinity of the negative electrode lattice ear is suppressed, and reprecipitation to the negative electrode lattice ear is suppressed.

  The Sb ions adsorbed on the silica surface are re-deposited on the negative electrode active material surface close to the separator surface when the battery is charged, so that the effect of improving the charge acceptability of the negative electrode is continuously obtained.

  In this example, when the separator A does not contain silica and Sb is contained in the negative electrode active material, the negative electrode lattice ear corrosion progresses remarkably, and due to the decrease in current collecting property, the life ends in less than 30000 cycles. did. It can be presumed that Sb eluted from the negative electrode due to overdischarge before the life test corroded on the negative electrode lattice ear and corroded the negative electrode lattice ear through the charge / discharge cycle.

  On the other hand, the battery of the comparative example containing the silica in the separator A and not containing Sb in the negative electrode active material had a reduced life cycle although the corrosion of the negative electrode lattice ear hardly proceeded. When the batteries after the end of their life were disassembled, lead sulfate, which is a discharge product, was accumulated on both the positive and negative plates. Comparison was made due to the decrease in battery charge acceptance during the charge / discharge cycle and the resulting lack of charge. It is thought that the life was over in a short period of time.

  Regarding the Sb concentration in the negative electrode active material, there is an effect of improving the life characteristics at 0.0002% by mass or more, but by setting it to 0.0004% by mass or more, high life characteristics can be obtained more stably. . In addition, when the Sb content is 0.007% by mass, the negative electrode lattice ear corrosion rate increases, so the Sb content is preferably 0.006% by mass or less. For these reasons, the Sb content in the negative electrode active material is more preferably 0.0004 to 0.006% by mass in order to achieve both the effect of improving the life characteristics and the effect of suppressing the negative electrode lattice ear corrosion.

  Moreover, regarding the silica content concentration in the separator A, a battery having 35% by mass added exhibits a remarkable life improvement effect and an effect of suppressing negative electrode lattice ear corrosion, but is extremely in the region of 40% by mass to 85% by mass. Significant lifetime improvement effect and corrosion suppression effect were obtained. In addition, when the silica content concentration exceeds 85% by mass, the effect of the present invention can be obtained. However, since the separator strength is lowered and the handling property in the manufacturing process is inferior, Is preferably in the range of 40% by mass to 85% by mass.

(Example 2)
The same positive electrode plate, negative electrode plate and connecting member alloy as in Example 1 above, and separator B described above as a separator were used in the combinations shown in Tables 5 and 6, and the positive electrode plate per cell as in Example 1. A liquid type 55D23 type lead acid battery for start-up (12V48Ah) was prepared, which was provided with an electrode plate group consisting of five sheets and six negative electrode plates, and the electrode plate surfaces were all immersed in the electrolyte.

  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 8, the battery of the comparative example using the alloy B containing Sb as the joining member of the positive electrode and the negative electrode had a life of less than about 30000 cycles, and the corrosion at the negative electrode lattice ear was also progressing. This is considered to be due to the fact that Sb contained in the positive electrode and negative electrode bonding members elutes into the electrolytic solution and re-deposits on the negative electrode grid edges, as in Example 1. When these test batteries were disassembled and quantitative analysis of Sb in the negative electrode lattice ear was performed, the presence of about 0.0005 mass% Sb in the negative electrode lattice ear was confirmed.

  On the other hand, the lead storage battery of the present invention, which contains Sb in the negative electrode active material, does not contain Sb in the positive and negative electrode bonding members and the grid, and contains silica in the fiber mat separator, is another comparative example. Compared with the lead storage battery of this type, the negative electrode lattice ear corrosion is suppressed and it has a good life cycle number. In addition, when these test batteries were disassembled and quantitative analysis of Sb in the negative electrode lattice ear was performed, Sb in an amount exceeding the detection limit (0.0001 mass%) could not be detected from the negative electrode lattice ear.

  As in Example 1, the Sb in the negative electrode active material improves the charge acceptability of the negative electrode plate, thereby significantly improving the battery life, and the Sb ions eluted in the electrolyte are separated from the separator. It is considered that the Sb reprecipitation on the negative electrode lattice ears and the corrosion of the negative electrode lattice ears due to the trapping by the silica therein was suppressed.

  In this example, when silica in the separator B was not included and Sb was included in the negative electrode active material, the negative electrode lattice ear corrosion progressed remarkably, and due to the decrease in the current collecting property, the life ended in less than 30000 cycles. . As in Example 1, it can be inferred that Sb eluted from the negative electrode due to overdischarge before the life test corroded on the negative electrode lattice ear and corroded the negative electrode lattice ear through the charge / discharge cycle.

  Even if the concentration of silica is 5% by mass, a remarkable life improvement effect and a negative electrode lattice ear corrosion effect can be obtained. However, when the silica content is 10% by mass to 40% by mass or more, a very remarkable life improvement effect and negative electrode lattice ear corrosion effect are obtained. Obtainable. In addition, the battery having a silica-containing concentration of 50% by mass has a life characteristic superior to that of the battery of the comparative example and the effect of suppressing the negative electrode lattice ear corrosion, but the life cycle number is slightly reduced, so the silica-containing concentration is 10% by mass. Most preferably, it is in the range of ˜40 mass%.

  In addition, compared with Example 1 using the separator A made of polyethylene sheet as described above, in Example 2 using the separator B of the glass fiber mat, even if the silica concentration is lower, the negative electrode lattice ear The effect of suppressing corrosion was obtained. This is because, in the separator made of polyethylene sheet, there is a portion where the surface of the silica is covered with polyethylene, whereas in the separator made of fiber mat, silica particles exist between the fibers. It can be considered that there are more surfaces that can adsorb ions.

  Moreover, the battery of the example of the present invention in Example 2 using the separator B of the glass fiber mat was superior to the battery of the example of the present invention in Example 1 using the separator A made of polyethylene sheet. Life characteristics were obtained. On the other hand, in the battery of the comparative example using the alloy A not containing Sb as the connecting member alloy of the positive electrode and the negative electrode, the glass fiber mat was compared with the battery of the comparative example in Example 1 using the separator A made of polyethylene sheet. The battery of the comparative example in Example 2 using the separator B had inferior life characteristics. It is not certain about the factor that the difference in the life characteristics due to the difference in the separator is opposite between the example of the present invention and the comparative example.

  Further, the Sb concentration in the negative electrode active material has an effect of improving the life characteristics at 0.0002% by mass or more, as in Example 1, but is more stable and high at 0.0004% by mass or more. Lifetime characteristics can be obtained. In addition, when the Sb content is 0.007% by mass, the negative electrode lattice ear corrosion rate increases, so the Sb content is preferably 0.006% by mass or less. For these reasons, the Sb content in the negative electrode active material is more preferably 0.0004 to 0.006% by mass in order to achieve both the effect of improving the life characteristics and the effect of suppressing the negative electrode lattice ear corrosion.

  As described above, it has been confirmed that the lead-acid 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 grid ear. .

  As described above, according to the lead-acid battery of the present invention, by improving the deterioration of the positive electrode in the deep discharge and the charge acceptability in the negative electrode, the deep discharge life characteristics are dramatically improved and the corrosion at the negative electrode grid 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 (2)

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, negative electrode grid and the negative electrode connecting member is made of lead or lead alloy containing no Sb, the Sb of the hydrogen overvoltage is less material than Pb in the negative electrode active material 0.0002 wt% to 0.007 The amount% including, and lead-acid battery which is characterized by comprising a synthetic resin sheet containing silica 40 wt% to 85 wt%, or a fiber mat containing silica from 10 to 40 wt% as a separator. The lead acid battery according to claim 1, wherein the Sb concentration in the negative electrode active material is 0.0004 to 0.006 mass%.

Images