JP2017016782A - Lead acid storage battery - Google Patents

Abstract

CONSTITUTION: In a lead acid storage battery, a negative electrode material contains an organic shrink-proofing agent, the organic shrink-proofing agent concentration of the negative electrode material has a distribution along the vertical direction of a negative electrode plate, and the average concentration in 1/3 of a lower part of the negative electrode plate is higher than that in 1/3 of an upper part.EFFECT: In a lead acid storage battery, the deterioration in high-rate discharge performance due to vibration and impact after repeated light charge/discharge or after being left for a long period of time can be reduced while sulfation in a negative electrode plate is suppressed.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a lead-acid battery, and more particularly to improvement of a negative electrode material.

  Conventionally, it has been required that the negative electrode plate of a lead storage battery is less susceptible to sulfation. As a countermeasure against this, it is known that a negative electrode electrode material contains a bisphenol sulfonic acid polymer. Here, sulfation is a phenomenon in which lead sulfate, which is difficult to reduce, accumulates in the negative electrode material.

  Related prior art is shown. Patent Document 1 (JP2008-277244) discloses that a naphthalene sulfonic acid polymer is contained in a negative electrode plate and a bisphenol sulfonic acid polymer is contained in a surface layer. According to Patent Document 1, high-rate discharge performance is improved by including a bisphenol sulfonic acid polymer in the surface layer of the negative electrode plate, and charge acceptance performance is improved by including a naphthalene sulfonic acid polymer inside.

  Patent Document 2 (JPH11-250913) discloses that a negative electrode material contains a mixture of a bisphenol sulfonic acid polymer and lignin sulfonic acid. According to Patent Document 2, the bisphenol sulfonic acid polymer prevents a decrease in surface area and shrinkage of the negative electrode material, and lignin sulfonic acid suppresses a decrease in discharge capacity at low temperatures.

JP2008-277244 JPH11-250913

The object of the present invention is to improve the life performance of lead-acid batteries used in PSOC (undercharged state), such as for idling stop cars, by suppressing sulfation of the lower part of the negative electrode plate without impairing the charge acceptability of the upper part of the negative electrode plate There is.
The object of the present invention is to suppress sulfation of the negative electrode plate, and to maintain high rate discharge performance within a practical range even after experiencing repeated vibrations and shocks after repeated shallow charge / discharge or prolonged standing. Is to make it.

  In the lead storage battery of the present invention, the negative electrode material contains an organic shrunk agent, and the organic shrunk agent concentration of the negative electrode material has a distribution along the vertical direction of the negative electrode plate. The density is higher than the average density in the upper 1/3.

  Further, in the lead storage battery of the present invention, the negative electrode material contains a plurality of types of organic shrinkage agents, and the total concentration of the organic shrinkage agents of the negative electrode material has a distribution along the vertical direction of the negative electrode plate, and the lower part of the negative electrode plate The average total concentration of the organic shrinkage agent in 1/3 is higher than the average total concentration of the organic shrinkage agent in the upper 1/3.

  In the lead storage battery of the present invention, the negative electrode material contains lignin sulfonic acid and a synthetic organic shrinkage agent, and the total concentration of the organic shrinkage agent of the negative electrode material has a distribution along the vertical direction of the negative electrode plate. The average total concentration of lignin sulfonic acid and synthetic organic shrinkage agent in the lower 1/3 of the board is higher than the average total concentration of lignin sulfonic acid and synthetic organic shrinkage agent in the upper 1/3 .

  In the present invention, the negative electrode material contains an organic shrinkage agent, and the organic shrinkage agent concentration of the negative electrode material has a distribution along the vertical direction of the negative electrode plate, and the average concentration in the lower third of the negative electrode plate is It is also on the negative electrode plate, which is higher than the average concentration in the upper third. And also in this case, the negative electrode material contains a plurality of organic shrinkage agents, and the average total concentration of the organic shrinkage agents in the lower 1/3 of the negative electrode plate is the average total concentration of the organic shrinkage agents in the upper 1/3 Higher than that. Also, the negative electrode material contains lignin sulfonic acid and a synthetic organic shrinkage agent, and the average total concentration of lignin sulfonic acid and synthetic organic shrinkage agent in the lower 1/3 of the negative electrode plate is lignin sulfone in the upper 1/3. It is particularly preferred that the concentration is higher than the average total concentration of the acid and the synthetic organic shrinking agent.

  With respect to the organic shrinking agent, the average concentration in the lower 1/3 of the negative electrode plate being higher than the average concentration in the upper 1/3 is preferably higher than 0.05 mass%. The organic anti-shrinking agent is a natural polymer sulfonic acid compound such as lignin sulfonic acid, and a synthetic polymer sulfonic acid compound such as bisphenol sulfonic acid or naphthalene sulfonic acid polymer, particularly those having an aromatic ring in the skeleton, It is arbitrary whether a sulfone group is an acid type or a salt type. The concentration of the organic shrunk agent is an average concentration in each part when the negative electrode material is divided into three parts in the upper, middle, and lower parts. For example, a plurality of electrode materials are collected from each part in the upper, middle, and lower parts, and the average concentration is determined. taking measurement.

  Consider increasing the concentration of lignin sulfonic acid (hereinafter “lignin”) throughout the negative electrode plate. Lignin has an effect of preventing agglomeration of the negative electrode active material (metal lead) and coarsening (sulfation) of lead sulfate when charging and discharging are repeated, and maintaining a specific surface area. However, if the amount added is large (the concentration in the active material is high), the charge acceptance is reduced. For this reason, when the lignin concentration is simply increased, the charging efficiency of the upper part of the negative electrode plate having a higher current density than that of the lower part is lowered. For this reason, in an automobile idling stop battery or the like that is charged in a short time with a large current, the life performance is not improved even if the lignin concentration is increased.

  When the SOC during charging / discharging is low, the sulfation under the negative electrode plate due to the stratification of the electrolyte causes the life. Note that SOC means a state of charge. When fully charged, the SOC becomes 100%. When discharged, the SOC becomes lower. However, increasing the lignin concentration suppresses sulfation, and the capacity can be recovered with SOC recovery charge. On the other hand, since the lignin concentration is increased, the charge acceptance performance at the upper part of the negative electrode plate is lowered and the idling stop life is not so increased. Therefore, if the amount of lignin in the lower part is increased and the lignin concentration in the upper part, where the charging efficiency is likely to be reduced, is deferred or somewhat reduced, the high rate charge acceptability is improved and the decrease in SOC is suppressed, and high rate charge is repeated. The service life is improved.

  The same is true when using synthetic organic shrinkage agents such as bisphenol sulfonic acid condensates instead of lignin. By increasing the concentration at the bottom of the negative electrode plate above the concentration at the top, the power receiving capability at the top of the negative electrode plate is improved. At the same time, the sulfation under the negative electrode plate is suppressed, and the life performance such as idling stop is improved. Note that the optimum concentration of the synthetic organic anti-shrink agent is slightly lower than that of lignin.

  In the present invention, the charge acceptability of the upper part of the negative electrode plate is not impaired, the sulfation of the lower part of the negative electrode plate is suppressed, and the life performance of the lead storage battery used in PSOC (undercharged state) is improved, such as for an idling stop vehicle. it can.

In the lead acid battery of the present invention, the negative electrode material contains lignin and a synthetic aromatic sulfonic acid polymer,
The average concentration of lignin of the negative electrode material is 0.1 mass% or more and 0.3 mass% or less,
There is a distribution along the vertical direction in the synthetic aromatic sulfonic acid polymer concentration of the negative electrode material,
The average concentration in the upper third of the negative electrode plate is 0 or more and 0.15 mass% or less,
The average concentration in the central 1/3 is 0 or more and 0.25 mass% or less, more than the concentration in the upper 1/3, and less than the concentration in the lower 1/3,
The average density in the lower 1/3 is 0.1 mass% or more and 0.25 mass% or less, and the average density in the lower 1/3 is 0.05 mass% or more higher than the average density in the upper 1/3.

That is, the feature of the present invention is in the negative electrode plate of the lead storage battery, the negative electrode material contains lignin and a synthetic aromatic sulfonic acid polymer,
The average concentration of lignin of the negative electrode material is 0.1 mass% or more and 0.3 mass% or less,
There is a distribution along the vertical direction in the synthetic aromatic sulfonic acid polymer concentration of the negative electrode material,
The average concentration in the upper third of the negative electrode plate is 0 or more and 0.15 mass% or less,
The average concentration in the central 1/3 is 0 or more and 0.25 mass% or less, more than the concentration in the upper 1/3, and less than the concentration in the lower 1/3,
The average density in the lower 1/3 is 0.1 mass% or more and 0.25 mass% or less, and the average density in the lower 1/3 is 0.05 mass% or more higher than the average density in the upper 1/3.

  Explaining the concentration of lignin, even if this concentration is less than 0.1 mass% or more than 0.3 mass%, the high-rate discharge performance deteriorates due to repeated shallow charge / discharge or vibration and impact after standing for a long time, or deep charge / discharge As a result, the high rate discharge performance decreases. Therefore, the average concentration of lignin is preferably 0.1 mass% or more and 0.3 mass% or less.

  If the average concentration of the synthetic aromatic sulfonic acid polymer in the lower third of the negative electrode plate exceeds 0.25 mass%, high-rate discharge performance decreases due to vibration and impact after repeated shallow charge / discharge or prolonged exposure. . Further, when the average concentration of the synthetic aromatic sulfonic acid polymer in the lower third of the negative electrode plate is less than 0.1 mass%, sulfation is likely to proceed, and the high rate discharge performance decreases due to deep charge / discharge. Therefore, the average concentration of the synthetic aromatic sulfonic acid polymer in the lower 1/3 is limited to 0.1 mass% or more and 0.25 mass% or less.

  If the average concentration of the synthetic aromatic sulfonic acid polymer in the upper third of the negative electrode plate exceeds 0.15 mass%, the high-rate discharge performance decreases due to vibration and impact after repeated shallow charge / discharge or prolonged standing. . The concentration in the upper 1/3 may be 0. And even if the difference between the average concentration of the synthetic aromatic sulfonic acid polymer in the lower 1/3 and the average concentration in the upper 1/3 is less than 0.05 mass%, vibration after repeated shallow charge / discharge or prolonged standing And high-rate discharge performance is reduced by impact. If the average concentration of the synthetic aromatic sulfonic acid polymer in the middle part 1/3 is higher than that in the lower part 1/3, the high-rate discharge performance decreases due to repeated charge / discharge or vibration and impact after standing for a long time. To do. When the average concentration of the synthetic aromatic sulfonic acid polymer in the middle part 1/3 is lower than that in the upper part 1/3, the high rate discharge performance is deteriorated by repeated deep charge / discharge.

  And when all of the above conditions are satisfied, high rate discharge performance can be maintained even when experiencing repeated vibrations and impacts after repeated shallow charge / discharge or prolonged standing, while suppressing sulfation of the negative electrode plate. .

  The synthetic aromatic sulfonic acid polymer is, for example, a bisphenol sulfonic acid polymer or a naphthalene sulfonic acid polymer, and a bisphenol sulfonic acid polymer is preferable.

  Preferably, the average concentration of the synthetic aromatic sulfonic acid polymer in the upper third of the negative electrode plate is 0 or more and 0.1 mass% or less. If the concentration at the upper 1/3 is 0.1 mass% or less, high rate discharge performance can be more reliably maintained even after experiencing repeated charging / discharging or vibration and impact after standing for a long time.

The present invention also removes sulfuric acid by washing the negative electrode plate taken out from the lead acid battery,
From the negative electrode plate from which the sulfuric acid content was removed, the negative electrode material in the upper 1/3 of the negative electrode plate and the negative electrode material in the lower 1/3 were collected,
Immerse each collected negative electrode material in 1 mol / l NaOH aqueous solution,
After desalting the solution from which insoluble components have been removed by filtration, the mass ratio between the powder sample obtained by concentration and drying and the collected negative electrode material is lower in the lower 1/3 of the negative electrode plate than in the upper 1/3 It exists in the lead acid battery and negative electrode plate which are characterized by being high.

  The powder obtained by the above procedure is almost all organic shrinkage agents such as lignin and synthetic organic shrinkage agents in practical lead storage batteries, and most of them are organic shrinkage agents even if not almost all. By the above procedure, the concentration ratio of the organic anti-shrink agent in the negative electrode material and the concentration ratio at the top and bottom of the negative electrode plate are obtained. And by making the mass ratio of the above powder sample and the collected negative electrode material higher in the lower 1/3 of the negative electrode plate than in the upper part 1/3, the charge acceptance at the upper part of the negative electrode plate is not impaired, and the lower part of the negative electrode plate Sulfation can be suppressed, and the life performance of lead-acid batteries used in PSOC (undercharged state), such as for idling stop vehicles, can be improved.

Characteristic diagram showing the effect of the bisphenol sulfonic acid polymer concentration in the upper 1/3 when the lignin concentration is fixed at 0.2 mass% and the bisphenol sulfonic acid polymer concentration in the lower 1/3 is fixed at 0.2 mass% Characteristic diagram showing the effect of the bisphenol sulfonic acid polymer concentration in the upper 1/3 when the lignin concentration is fixed at 0.05 mass% and the bisphenol sulfonic acid polymer concentration in the lower 1/3 is fixed at 0.2 mass% Characteristic chart showing the effect of bisphenol sulfonic acid polymer concentration in the upper 1/3 when the lignin concentration is fixed at 0.2 mass% and the bisphenol sulfonic acid polymer concentration in the lower 1/3 is fixed at 0.3 mass% When the lignin concentration was fixed at 0.2 mass% and the bisphenol sulfonic acid polymer concentration at the upper 1/3 and middle 1/3 was fixed at 0.05 mass%, the bisphenol sulfonic acid polymer concentration at the lower 1/3 Characteristic diagram showing impact When the lignin concentration was fixed at 0.2 mass% and the bisphenol sulfonic acid polymer concentration at the middle 1/3 and lower 1/3 was fixed at 0.2 mass%, the bisphenol sulfonic acid polymer concentration at the upper 1/3 Characteristic diagram showing impact When the lignin concentration is fixed at 0.2 mass% and the bisphenol sulfonic acid polymer concentration at the upper 1/3 and middle 1/3 is fixed at 0.2 mass%, the bisphenol sulfonic acid polymer concentration at the lower 1/3 Characteristic diagram showing impact Schematic diagram of a negative electrode plate with an expanded lattice having an upper frame and a lower frame Schematic diagram of a negative electrode plate with an expanded lattice without a lower frame Schematic diagram of a negative electrode plate with a grid with top, bottom, left and right frames

  Hereinafter, an optimum embodiment of the present invention will be described. In carrying out the present invention, the embodiments can be appropriately changed in accordance with common sense of those skilled in the art and disclosure of prior art. In Examples, the negative electrode material may be referred to as a negative electrode active material, and the positive electrode material may be referred to as a positive electrode active material. The negative electrode plate comprises a negative electrode current collector (negative electrode lattice) and a negative electrode material (negative electrode active material), and the positive electrode plate comprises a positive electrode current collector (positive electrode lattice) and a positive electrode material (positive electrode active material). The solid components other than the current collector belong to the electrode material.

  7 to 9 show the negative electrode plate of the example. In the negative electrode plate 2 of FIG. 7, the expanded lattice 4 includes an upper edge 5, a lower edge 6, ears 7, and crosspieces 8, and a negative electrode active material (negative electrode electrode material) is held in a square surrounded by the crosspieces 8. Yes. The negative electrode active material is held between the bottom surface of the upper edge 4 and the upper surface of the lower edge 6, and the boundary line along the bottom surface of the upper edge 4 is denoted by H1, and the boundary line along the upper surface of the lower edge 6 is denoted by H4. The bisector that divides the height H1 and the height H4 into three equal parts in the vertical direction is denoted by H2 and H3. The negative active material 11 in the upper part 1/3 between the lines H1 and H2, the negative active material 12 in the middle 1/3 between the lines H2 and H3, and the negative active material 13 in the lower 1/3 between the lines H3 and H4. Yes. The negative electrode plate 2 has the side with the ears 7 as the upper side and the side with the lower edge 6 as the lower side. When calculating the average concentration of the organic pre-shrinking agent, avoid the grids that intersect with the bisectors H2 and H3, for example, the upper, middle, and lower parts from the hatched grids in FIG. 7, FIG. 8, and FIG. A plurality of grids are selected for each, and the average density at the plurality of grids is measured.

  In the negative electrode plate 22 of FIG. 8, the expanded lattice 4 ′ has no lower edge, and defines the lines H1 to H4 as in FIG. 7, and the negative active material between the lines H1 and H2 is similarly defined as the negative active material in the upper 1/3. 11, the negative electrode active material between the lines H2 and H3 is the negative electrode active material 12 of the middle 1/3, and the negative electrode active material between the lines H3 and H4 is the negative electrode active material 13 of the lower 1/3.

  In the negative electrode plate 32 of FIG. 9, a grid 34 having a frame around four circumferences such as a cast grid and a punched grid is used, vertical frames 35 and 36 are added, and a bar 38 extending vertically is used instead of the diagonal bar 8. ing. Also in this case, lines H1 to H4 are defined in the same manner as in FIG. 7, and the negative electrode active material between the lines H1 and H2 is defined as the negative electrode active material 11 in the upper part, and the negative electrode active material between the lines H2 and H3 is the middle. The negative electrode active material 12 is 1/3, and the negative electrode active material between the lines H3 and H4 is the negative electrode active material 13 of the lower 1/3.

  In addition, when the negative electrode plate has no grid and the negative electrode plate extends in the vertical direction, the negative electrode active material is divided into three equal parts in the height direction, the upper 1/3 negative electrode active material, and the middle 1/3 negative electrode active material. The negative active material for the lower third is defined.

Manufacture of lead acid battery Bisphenol formaldehyde condensate and lignin were used as organic shrinkage agents. The bisphenol formaldehyde condensate contains a sulfonic acid group, and may contain a sulfonyl group in addition to this. The type of bisphenol may be any of A type, F type, and S type, and the type of condensing agent is arbitrary. The sulfonic acid group may be directly bonded to the bisphenol skeleton, or may be bonded to a phenyl group or the like different from the skeleton. The S element content contained in the used bisphenol formaldehyde condensate is about 5000 μmol / g, but the S element content is arbitrary, for example, in the range of 2000 to 8000 μmol / g. Furthermore, lignin may be added in acid form instead of salt form. Then, along the height direction of the negative electrode plate, the composition and concentration of the organic anti-shrink agent were changed in the upper part 1/3, the middle part 1/3, and the lower part 1/3.

  Lead powder, organic shrinkage agent, barium sulfate and synthetic fiber reinforcing material were kneaded with water and sulfuric acid to obtain a negative electrode active material paste. 1 mass% of barium sulfate and 0.1 mass% of the synthetic fiber reinforcing material were contained in the negative electrode active material after conversion (strictly, the negative electrode material). The preferable content ranges of these components are 0.2 mass% or more and 2.0 mass% or less for barium sulfate, 0.05 mass% or more and 0.2 mass% or less for the synthetic fiber reinforcing material, and may further contain carbon or the like. The negative electrode active material paste was filled in a negative electrode lattice made of a Pb-0.09 mass% Ca-0.7 mass% Sn alloy, dried and aged to obtain an unformed negative electrode plate. The kind of lead powder, manufacturing conditions, etc. are arbitrary, and the negative electrode active material may contain components other than those described above.

Lead powder and a synthetic fiber reinforcing material (0.1 mass% with respect to the formed positive electrode active material) were kneaded with water and sulfuric acid to obtain a positive electrode active material paste. This paste was filled in a positive electrode grid made of an alloy of Pb-0.06 mass% Ca-1.3 mass% Sn, dried and aged to obtain an unformed positive electrode plate. The unformed negative electrode plate is accommodated in a bag-shaped separator made of microporous polyethylene, and 5 unformed positive electrode plates and 6 unformed negative electrode plates per cell are placed facing each other and electrolyzed. Liquid was added to form a battery case, and a liquid lead acid battery with 12V output was produced. The density of the negative electrode active material after chemical conversion was set to the usual 3.6 g / cm ³ , but even if a negative active material with a low density of 2.9 g / cm ³ was used, the influence of the concentration distribution of the organic shrinkage agent was 3.6 g / cm 3. It was the same as the case of ³ . The lead-acid battery may be a control valve type, and the type and composition of the lattice are arbitrary. Further, a cored bar such as a Pb—Sb—As alloy may be used for the current collector of the positive electrode instead of the lattice.

Measuring method Identification of the organic anti-shrink agent species in the negative electrode active material is performed as follows. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove sulfuric acid, and dried. Extract the active material from the negative electrode plate, immerse the active material in 1 mol / l NaOH aqueous solution to extract the organic anti-shrink agent, desalinate the solution from which the insoluble components have been removed by filtration, concentrate and dry the powder sample Get. A powder sample is diluted with distilled water, and an organic-shrinking agent species is specified by an ultraviolet-visible absorption spectrum obtained by an ultraviolet-visible absorbance meter. If the UV-visible absorption spectrum is insufficient, prepare a powder sample obtained by concentration and drying, and use other analytical instruments that can analyze the structure, such as infrared spectroscopy (IR) and NMR. Use.

  The content of the organic shrinking agent in the negative electrode active material is measured as follows. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove sulfuric acid, and dried. The negative electrode active material of the negative electrode plate is divided into three equal parts in the vertical direction as shown in FIGS. 7 to 9, avoiding the cells intersecting with the bisectors H2 and H3, a plurality of cells from each portion, for example 3 The negative electrode active material is collected for each square and mixed for each of the upper, middle, and lower portions. In this way, a sample in which the concentration of the organic shrinking agent is averaged in the upper, middle and lower portions is collected. For each of the upper, middle and lower parts, 10 g of the active material sample is immersed in 30 ml of 1 mol / l NaOH aqueous solution to extract the organic anti-shrink agent, and after removing insoluble components in the solution by filtration, the UV-visible absorption spectrum is measured. The content of the organic shrinking agent in the active material is measured using a calibration curve prepared in advance.

  When a plurality of organic shrinking agents are mixed, they are separated by the following method to identify the organic shrinking agent species. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove sulfuric acid, and dried. Extract the active material from the negative electrode plate, immerse the active material in a 1 mol / l NaOH aqueous solution to extract the organic anti-shrink agent, and remove the insoluble components by filtration. The solution is desalted and fractionated using a gel column or the like. Separate each component. The UV-visible absorption spectrum of each separated sample is measured to identify the organic shrinking agent species. If the UV-visible absorption spectrum is insufficient, the sample separated for each component is concentrated and dried to form a powder sample, then other analytical instruments that can analyze the structure, such as infrared spectroscopy (IR), NMR Etc. are used to identify the structure.

  When a plurality of organic shrinking agents are mixed, the content is calculated by the following method. The fully charged lead acid battery is disassembled, the negative electrode plate is taken out, washed with water to remove sulfuric acid, and dried. The negative electrode active material of the negative electrode plate is divided into three equal parts vertically as shown in FIGS. 7 to 9, and a plurality of squares from each part, for example 3 The negative electrode active material is collected for each square and mixed for each of the upper, middle, and lower portions. In this way, a sample in which the concentration of the organic shrinking agent is averaged in the upper, middle and lower portions is collected. For each of the upper, middle and lower parts, 10 g of active material sample is immersed in 30 ml of 1 mol / l NaOH aqueous solution to extract the organic anti-shrink agent, and the NaOH aqueous solution from which insoluble components have been removed by filtration is used for the gel column whose yield has been determined in advance. Desalinate and fractionate using ingredients to separate each component. Measure the UV-visible absorption spectrum of each separated sample, calculate the content using a calibration curve prepared in advance, and calculate the content of the organic shrinking agent in the active material from the calculated content and the column yield. calculate.

Performance test 1: Idling stop life Lead-acid battery is discharged at 10A up to a final voltage of 10.2V at 25 ° C and charged three times as much as 1.3 times the discharge electricity at 10A. The capacity. According to the standard of battery industry association (SBA) battery for idling stop car, 45A x 59sec discharge, 300A x 1sec discharge, and 14.0V (limit current 100A) x 60sec charge cycle, The life was determined when the voltage was 300A discharged and the voltage at 1 sec was lower than 7.2V.

  Table 1 shows the idling stop life (IS life) when the concentration of lignin was changed between the upper, middle, and lower sides of the negative electrode plate without using a synthetic organic shrinkage agent. Increasing the amount of lignin in the lower part of the conventional example (lignin 0.2 mass%) and deferring the lignin concentration in the upper part, where the charging efficiency is likely to be lowered, or reducing it slightly improves high-rate charge acceptance and lowers the SOC (charged state) Was suppressed, and the idling stop life was improved (Table 1).

  Table 2 shows the results when using synthetic organic shrinkage agents (bisphenols) instead of lignin. As in the case of lignin, the idling stop life was improved by making the upper concentration lower than the lower concentration. However, the optimum value of the anti-shrinkage agent concentration was lower than that of lignin, and it was more effective to reduce the upper concentration than to increase the lower concentration.

Performance Test 2: High Rate Discharge Performance In both the case of lignin and the synthetic organic shrinkage agent, the idling stop life could be improved by making the concentration of the shrinkage preventing agent at the upper part of the negative electrode plate lower than the concentration of the lowering agent. Therefore, we studied to further improve the high rate discharge performance by using lignin and synthetic organic shrinkage agent in combination.

The initial 5-hour rate capacity and high rate discharge capacity of the lead acid battery were measured. Next, with a discharge depth (DOD) where the 5-hour rate capacity (C ₅ ) is 100%, 10% discharge and 120% charge are performed at 40 ° C for 5000 cycles, and after 5000 cycles, 10 ° C, 1.5C _After discharging at ₅ A, the terminal voltage at 5 seconds was measured. This test is called test L and is used as an index of durability of high rate discharge performance against shallow charge / discharge. For some batteries, after initial performance measurement, after leaving at 40 ° C for 240 days, add 2.5G vibration for 2h up and down, and then discharge at 10 ° C and 1.5 C ₅ A for 5 second terminal voltage The test which measures was performed. Since the result of the test in which vibration was applied after being left for a long time showed a high correlation with the result of test L, the vibration test after being left for a long time was omitted. The cause of the performance deterioration in Test L was the shrinkage of the negative electrode active material and the peeling from the lattice.

A lead-acid battery after initial performance measurement, which is different from the one used for test L, was subjected to 700 cycles of DOD 70% deep discharge and 115% charge discharge at 40 ° C and 700 cycles after 10 cycles. After discharging at 1.5 C ₅ A, the terminal voltage at 5 seconds was measured. This test is referred to as test H. The cause of the performance deterioration in Test H was sulfation of the negative electrode active material.

Test Results Tables 3 to 12 and FIGS. 1 to 6 show the test results regarding the high rate discharge performance when using plural kinds of organic shrinking agents. The organic shrinkage agent A represents lignin, the organic shrinkage agent B represents a bisphenol formaldehyde condensate, the organic shrinkage agent C represents a naphthalene sulfonic acid formaldehyde condensate, and the unit of content is mass%. The test results are shown as relative values with the first conventional product in Table 3 as 100%. Table 3 shows representative results, and neither bisphenol formaldehyde condensate nor lignin alone could achieve durability in both tests L and H. When the concentration of the bisphenol formaldehyde condensate in the upper part of the negative electrode plate was made lower than that in the lower part, in both Test L and Test H, high high rate discharge performance could be maintained. Further, when the concentration of the bisphenol formaldehyde condensate in the lower third was 0.3 mass%, the high rate discharge performance after the test L was insufficient.

  Table 4 shows the influence of the concentration of bisphenol formaldehyde condensate when the concentration of lignin is fixed at 0.2 mass%. Good results were obtained by increasing the concentration of bisphenol formaldehyde condensate in the lower 1/3 higher by 0.05 mass% than in the upper 1/3. However, when the concentration in the lower 1/3 was 0.3 mass%, the high-rate discharge performance was lowered by the test L that repeated shallow charge and discharge.

  Table 5 shows additional results when the lignin concentration was fixed at 0.2 mass%. When the concentration of the bisphenol formaldehyde condensate was the same in the upper 1/3 and the lower 1/3, and the concentration of the bisphenol formaldehyde condensate was uniform, good results were not obtained. It was also found that the concentration in the lower 1/3 must be higher than that in the upper 1/3 and the concentration in the lower 1/3 should be less than 0.3 mass%. Furthermore, it was found that the concentration of the middle 1/3 may be equal to the upper 1/3 or the lower 1/3.

  Tables 6 and 7 show the results when the lignin concentration was changed to 0.1 mass% or 0.3 mass%. The results were similar to Table 3.

  Summarizing the results in Tables 3 to 7, to obtain good results for both L and H tests, the bisphenol formaldehyde condensate requires a top and bottom concentration distribution, with the lower 1/3 concentration being the upper It was found that it was necessary to make it higher by 0.05 mass% than the concentration of 1/3. It was also found that the concentration in the lower 1/3 should be less than 0.3 mass% and greater than 0.05 mass%. From this, the concentration of the lower 1/3 was set to 0.1 mass% or more and 0.25 mass% or less. Further, it was found that the concentration of the upper 1/3 should be 0 or more and 0.15 mass%, preferably 0 or more and 0.1 mass% or less. It was also found that the concentration in the middle 1/3 must be higher than the upper concentration and lower than the lower concentration.

  Table 8 shows the results when the concentration of lignin was fixed at 0.4 mass%. Even if the concentration of the bisphenol formaldehyde condensate was changed variously, good results were not obtained.

  The concentration of lignin was fixed at 0.2 mass%, and the main results were extracted from Tables 4 and 5 and shown in Table 9 and FIG. It can be seen that good results are obtained when the concentration of the bisphenol formaldehyde condensate in the upper third is 0.05 mass% and 0.1 mass%, but good results cannot be obtained when the concentration is 0.2 mass% or more. For this reason, the concentration of the bisphenol formaldehyde condensate in the upper part 1/3 is set to 0.15 mass% or less, preferably 0.1 mass% or less.

  The results when the concentration of lignin was fixed at 0.05 mass% are shown in Table 10 and FIG. Even if the concentration of the bisphenol formaldehyde condensate was changed variously, good results were not obtained.

  As described above, good results were not obtained when the concentration of lignin was 0.05 mass% or 0.4 mass%, but good results were obtained at 0.1 mass% to 0.3 mass%. Therefore, the concentration of lignin was set to 0.1 mass% or more and 0.3 mass%.

  From Table 3, Table 4, and Table 5, data in which the concentration of the bisphenol formaldehyde condensate in the lower third is 0.3 mass% is extracted and shown in Table 11 and FIG. 3 together with the additional results. The concentration of lignin was fixed at 0.2 mass%. It can be seen that good results cannot be obtained by variously changing the concentration of the bisphenol formaldehyde condensate in the upper 1/3 and the middle 1/3.

  Table 12 shows a comparison between a bisphenol formaldehyde condensate and a naphthalenesulfonic acid formaldehyde condensate. It has been found that naphthalenesulfonic acid formaldehyde condensate may be used in place of the bisphenol formaldehyde condensate. However, the performance was slightly inferior to the bisphenol formaldehyde condensate.

  FIG. 4 shows that lignin is uniformly contained in the negative electrode active material in an amount of 0.2 mass% regardless of whether it is upper, middle, or lower, the content of bisphenols in the upper 1/3 is 0.05 mass%, and the content in the middle 1/3 is also 0.05 mass. The results when the content of the lower part 1/3 is changed are shown extracted from each table. Good results were obtained for Test L when the content of bisphenols in the lower 1/3 was 0.1 mass% and 0.2 mass%, and the results for Test L were reduced at 0.3 mass%.

  Fig. 5 shows that lignin is uniformly contained in the negative electrode active material at 0.2 mass% regardless of the upper, middle, lower, the content of bisphenols in the middle part is 0.2 mass%, and the content in the lower part 1/3 is also 0.2 mass. The results when the content of the upper 1/3 is changed and fixed in% are extracted from each table and shown. Good results were obtained for Test L when the content of bisphenols in the upper 1/3 was 0.05 mass% and 0.1 mass%, and the results for Test L were decreased at 0.2 mass% or more.

  Fig. 6 shows that lignin is uniformly contained in the negative electrode active material in an amount of 0.2 mass% regardless of the upper, middle, lower, the content of bisphenols in the upper 1/3 is 0.2 mass%, and the content in the middle 1/3 is also 0.2 mass. The results when the content of the lower part 1/3 is changed are shown extracted from each table. When the content of bisphenols in the lower 1/3 was increased from 0.1 mass% and 0.2 mass% to 0.3 mass%, the result to Test H was improved, but the result to Test L was decreased. Moreover, since the density | concentration of the bisphenol of upper part and center part is too high, the result comparable to FIG. 4, FIG. 5 was not obtained.

  The concentration of lignin may be different between the upper and lower sides of the negative electrode plate, and the concentration of the upper third of the negative electrode plate is preferably lower than the lower one third. In that case, the average density is 0.1 mass% or more and 0.3 mass% or less, and preferably the average density of the upper 1/3, middle 1/3, and lower 1/3 is 0.1 mass% or more and 0.3 mass% or less.

2, 22, 32 Negative electrode plate 4, 4 'Expanded grid 5 Upper edge 6 Lower edge 7 Ear 8, 38 Cross 11 Upper 1/3 negative electrode active material 12 Middle 1/3 negative electrode active material 13 Lower 1/3 negative electrode Active material 34 lattice
35, 36 vertical frame
H2, H3 trisection

Claims (6)

The negative electrode material contains an organic shrunk agent, and the organic shrunk agent concentration of the negative electrode material has a distribution along the vertical direction of the negative electrode plate,
A lead acid battery characterized in that the average concentration in the lower third of the negative electrode plate is higher than the average concentration in the upper third. The negative electrode material contains a plurality of organic shrinkage agents, and the total concentration of the organic shrinkage agents of the negative electrode material has a distribution along the vertical direction of the negative electrode plate,
A lead acid battery, characterized in that the average total concentration of the organic shrinking agent in the lower 1/3 of the negative electrode plate is higher than the average total concentration of the organic shrinking agent in the upper 1/3. The negative electrode material contains lignin sulfonic acid and a synthetic organic shrinkage agent, and the total concentration of the organic shrinkage agent of the negative electrode material has a distribution along the vertical direction of the negative electrode plate,
The average total concentration of lignin sulfonic acid and synthetic organic shrinkage agent in the lower 1/3 of the negative electrode plate is higher than the average total concentration of lignin and synthetic organic shrinkage agent in the upper 1/3, Lead acid battery. The negative electrode material contains lignin sulfonic acid and a synthetic aromatic sulfonic acid polymer,
The average concentration of lignin sulfonic acid of the negative electrode material is 0.1 mass% or more and 0.3 mass% or less,
There is a distribution along the vertical direction in the synthetic aromatic sulfonic acid polymer concentration of the negative electrode material,
The average concentration in the upper third of the negative electrode plate is 0 or more and 0.15 mass% or less,
The average concentration in the central 1/3 is 0 or more and 0.25 mass% or less, more than the concentration in the upper 1/3, and less than the concentration in the lower 1/3,
The average density in the lower 1/3 is 0.1 mass% or more and 0.25 mass% or less, and the average density in the lower 1/3 is 0.05 mass% or more higher than the average density in the upper 1/3. Lead acid battery.   The lead acid battery according to claim 3 or 4, wherein the average concentration of the synthetic aromatic sulfonic acid polymer in the upper third of the negative electrode plate is 0 or more and 0.1 mass% or less. The negative electrode plate removed from the lead-acid battery was washed with water to remove the sulfuric acid,
From the negative electrode plate from which the sulfuric acid content was removed, the negative electrode material in the upper 1/3 of the negative electrode plate and the negative electrode material in the lower 1/3 were collected,
Immerse each collected negative electrode material in 1 mol / l NaOH aqueous solution,
After demineralizing the NaOH aqueous solution from which insoluble components have been removed by filtration, the mass ratio between the powder sample obtained by concentration and drying and the collected negative electrode material is 1/3 in the lower 1/3 of the negative electrode plate. Lead acid battery characterized by being higher than.