JP2021111445A - Lead-acid battery - Google Patents

Abstract

To provide a novel lead-acid battery which can be expected to achieve both the suppression of a dendrite short circuit when being used in a partial state of charge and the suppression of a decrease in water in an electrolyte during overcharge at high temperatures.SOLUTION: A lead-acid battery includes a cell chamber and an electrode plate group stored in the cell chamber together with an electrolyte, the electrode plate group including a laminate comprising a negative electrode plate and a positive electrode plate alternately arranged therein and a separator arranged between the negative electrode plate and the positive electrode plate. The positive electrode plate comprises a collector and a positive electrode mixture held on a lattice substrate of the collector. The density of the positive electrode mixture is 4.3 g/cm3 or more. The electrolyte contains at least one of aluminum ions and lithium ions, and a polymer surfactant. The total concentration of aluminum ions and lithium ions is 0.01 mol/L or more and 0.30 mol/L or less, and the concentration of the polymer surfactant is 0.002% by mass or more.SELECTED DRAWING: None

Description

The present invention relates to a lead storage battery.

In recent years, the electrification of vehicles has been rapidly progressing in order to reduce the environmental load. Although idling stop vehicles, micro hybrid vehicles, and mild hybrid vehicles are inferior in fuel efficiency to strong hybrid vehicles, they are popular because they can be purchased at a relatively low price by users, and automobile manufacturers are also focusing on development.
Lead-acid batteries installed in idling stop vehicles, micro-hybrid vehicles, and mild hybrid vehicles are used in harsher environments than before. For example, lead-acid batteries are required to have higher durability and charge acceptability, such as an increase in the number of engine starts, power supply to electrical components during idling stop, and regenerative charging by a brake.

In order to improve the durability of the lead storage battery, it is effective to improve the active material density of the positive electrode. This is because the positive electrode active material of the lead storage battery becomes coarse due to charging and discharging, and the binding of the active material particles gradually decreases. It is a well-known fact that this phenomenon called softening can be suppressed to some extent by increasing the density of active material. It is also a well-known fact that the specific surface area is increased by increasing the amount of conductive carbon in the negative electrode in order to improve charge acceptability.
However, in recent years, there has been a movement to further increase the electric power taken out from the lead-acid battery to improve fuel efficiency, and the lead-acid battery needs to be further improved in durability and charge acceptability. Therefore, a lead-acid battery containing aluminum ions or lithium ions in the electrolytic solution by increasing the density of the active material of the positive electrode has been put into practical use. A lead-acid battery containing aluminum ions or lithium ions in the electrolytic solution is described in Patent Document 1 and Patent Document 2.

On the other hand, by suppressing the decrease in water content in the electrolytic solution, it is possible to reduce the frequency of maintenance for replenishing water in the battery case of the lead storage battery. The decrease in water content in the electrolytic solution is more likely to occur at higher temperatures. Therefore, it is expected that micro-hybrid vehicles and mild hybrid vehicles will rapidly spread in Southeast Asia, which is a high-temperature region, and the ability to suppress the decrease in water content in the electrolyte is important for lead-acid batteries for idling stop vehicles. It can be said that it is one of the excellent performances.
Patent Document 3 describes a liquid-type lead-acid battery in which a lattice of Pb—Ca alloy is used for the positive electrode and the negative electrode for the purpose of suppressing a decrease in water content in the electrolytic solution.

In addition, since lead-acid batteries for idling stop are usually used in a partial state of charge (PSOC), dendrite shorts (lead dendritic deposits (dendrite) grow from the electrodes) when charged after being left for a long period of time. Therefore, there is a high possibility that a short circuit will occur by breaking through the separator. As a method for preventing this dendrite short circuit, for example, Patent Document 4 proposes a structure in which the separator has a structure that suppresses the penetration of dendrites in the entire microporous film.
However, Patent Documents 1 to 4 do not describe suppressing both the decrease in water content and the dendrite short circuit during high-temperature overcharging.

Japanese Unexamined Patent Publication No. 2013-134957 Japanese Patent No. 4799560 Japanese Patent No. 4857894 WO2016 / 59739 Pamphlet

An object of the present invention is to provide a novel lead-acid battery that can be expected to suppress both dendrite short-circuiting when used in a partially charged state and suppression of water reduction in an electrolytic solution during high-temperature overcharging.

In order to solve the above problems, the lead storage battery of one aspect of the present invention has the following configurations (1) to (3).
(1) A cell chamber, a group of plates housed in the cell chamber, and an electrolytic solution injected into the cell chamber are provided. The electrode plate group is a lead-acid battery having a laminated body composed of alternately arranged negative electrode plates and positive electrode plates and separators arranged between the negative electrode plates and the positive electrode plates. The positive electrode plate is composed of a current collector and a positive electrode mixture held on a grid-like substrate of the current collector.
(2) The density of the positive electrode mixture is 4.3 g / cm ³ or more.
(3) The electrolytic solution contains at least one of aluminum ions and lithium ions, and a polymer surfactant. The total concentration of aluminum ions and lithium ions is 0.01 mol / L or more and 0.30 mol / L or less, and the concentration of the polymer surfactant is 0.002% by mass or more.

The lead-acid battery of the present invention is a novel lead-acid battery, and according to the lead-acid battery of the present invention, it suppresses dendrite short circuit when used in a partially charged state and suppresses the decrease in water content in the electrolytic solution during high temperature overcharging. Both can be expected.

[Discussion]
As a result of various studies by the present inventors, it was concluded that one of the causes of the increase in the amount of water reduction in the lead storage battery containing aluminum ions and lithium ions in the electrolytic solution may be the presence of aluminum ions and lithium ions. It came to. It is speculated that aluminum ions and lithium ions suppress the overvoltage of the negative electrode during charging, and the amount of water reduction is increasing.
In addition, the reason why lead-acid batteries for idling stop, which contain aluminum ions and lithium ions in the electrolyte and have a high density of positive electrode active material, is prone to dendrite short-circuit after being left for a long period of time is because the amount of active material per amount of electrolyte is large. In addition to the tendency for dendrite shorts to occur, it is speculated that aluminum ions and lithium ions may be one of the causes. That is, it is considered that aluminum ions and lithium ions improve the solubility of lead sulfate crystals in an electrolytic solution by irregularizing and microcrystallizing lead sulfate crystals, and improve charge acceptability. However, it is considered that lead sulfate tends to grow into a dendrite shape by charging after being left for a long period of time due to the fact that lead sulfate crystals are easily dissolved in the electrolytic solution.

Then, in the lead-acid battery satisfying the above configurations (1) and (2), the electrolytic solution contains at least one of aluminum ions and lithium ions at a total concentration of 0.01 mol / L or more of aluminum ions and lithium ions. By containing a polymer surfactant at a concentration of 0.002% by mass or more in the electrolyte of a lead-acid battery containing 30 mol / L or less, the effect of suppressing dendrite shorts and high-temperature overcharging when used in a partially charged state are achieved. It was found that both the effects of suppressing the decrease in water content in the electrolytic solution at that time can be expected.
Considering the reason why the amount of water reduction (water reduction amount) during high-temperature overcharging is suppressed, the solubility of the added polymer surfactant rapidly increases at high temperature, and adsorption of aluminum ions and lithium ions to the negative electrode. It is presumed that by inhibiting the above, the overvoltage suppression effect of the negative electrode by these ions is inhibited (the hydrogen generation potential is shifted to the base side at high temperature). Therefore, it is considered that the amount of water reduction during high-temperature overcharging may be suppressed.

Next, considering the reason why dendrite shorts are suppressed, it is considered that the edge portion of lead sulfate irregularized and microcrystallized by these ions becomes the growth point of dendrite, but it is irregularized and microcrystallized. Lead sulfate has more edges than normal lead sulfate, and it is thought that dendrites are likely to occur. Then, it is speculated that the polymer surfactant is adsorbed on the irregular and microcrystallized lead sulfate edge portion, so that the dendrite growth from the edge portion is suppressed.

The concentration of the polymer surfactant in the electrolytic solution is 0.002% by mass or more. If it is less than 0.002% by mass, no effect is exhibited. The upper limit is not particularly determined, but if it exceeds 0.5% by mass, the PSOC durability is lowered, so that the preferable range is 0.002% by mass or more and 0.5% by mass or less. It is presumed that the reason why the PSOC durability is lowered when the amount of the polymer surfactant is too large is that the polymer surfactant causes steric hindrance and hinders the movement of sulfate ions and the like.
Polymer surfactants that can be used are anionic surfactants such as perfluorosulfonate, lignin sulfonate, lauryl sulfate, amphoteric surfactants such as polyasparaginate, and cations such as alkyltrimethylammonium chloride. It is a sexual surfactant and is an ionic surfactant.

As a result of species studies by the present inventors, it was found that when the polymer surfactant is a cationic polymer surfactant or an amphoteric polymer surfactant, the amount of water reduction during high-temperature overcharging is further suppressed. .. It is presumed that the reason for this is that in the case of cationic polymer surfactants and amphoteric polymer surfactants, they are more strongly adsorbed on the negative electrode in the overcharged state and the action is exhibited. It is presumed that the cationic polymer surfactant and the amphoteric polymer surfactant exhibit the same effect because the amphoteric surfactant exhibits cationicity in the acidic region.

In addition, as a result of species studies by the present inventors, it was found that when the polymer surfactant is an anionic polymer surfactant, dendrite shorts after being left for a long period of time are further suppressed. The reason for this is considered as follows. At the moment of charging after being left over-discharged, a water-soluble anionic polymer surfactant is adsorbed on the irregularized and microcrystallized lead sulfate, and this surfactant adsorbs lead ions. Elution of lead ions from the vicinity of the electrode into the electrolytic solution can be suppressed. From this, it is considered that dendrite growth in charging after being left over-discharged may be suppressed.

As a result of further studies by the present inventors, it was found that dendrite short-circuiting is further suppressed when the sodium ion concentration in the electrolytic solution is 50 ppm or more and 10000 ppm or less. It was a well-known fact that sodium ions suppress dendrite shorts, but it was found that when a polymer surfactant is contained in the electrolytic solution, the effect of suppressing dendrite shorts is exhibited with a small amount of sodium ions. .. There is also a report that sodium ions suppress dendrites but inhibit charge acceptability (GS Yuasa Technical Report Vol. 8, No. 2, 2011, p.22-28), so it is preferable to have less sodium ions. it is obvious.

[Embodiment]
Hereinafter, embodiments of the present invention will be described, but the present invention is not limited to the embodiments shown below. In the embodiments shown below, technically preferable limitations are made for carrying out the present invention, but these limitations are not essential requirements of the present invention.

[Constitution]
The lead-acid battery of this embodiment has a monoblock type battery case, a lid, and a group of six plates. The battery case is divided into six cell chambers by a partition wall. The six cell chambers are arranged along the longitudinal direction of the battery case. One electrode plate group is arranged in each cell chamber. An electrolytic solution is injected into each cell chamber.
Each electrode plate group has a laminate composed of a plurality of alternately arranged positive electrode plates and negative electrode plates, and separators arranged between the positive electrode plates and the negative electrode plates.

The positive electrode plate is made of a lead alloy, and a positive electrode mixture (a mixture containing a positive electrode active material) is held on a lattice-like substrate of a current collector having a lattice-like substrate and an ear portion protruding upward from the lattice-like substrate. It is a thing. The negative electrode plate is made of a lead alloy, and a negative electrode mixture (a mixture containing a negative electrode active material) is held on a lattice-like substrate of a current collector having a lattice-like substrate and an ear portion protruding upward from the lattice-like substrate. It is a thing. A plurality of positive electrode plates and negative electrode plates are alternately arranged via a separator. The number of negative electrode plates constituting the laminate may be one more than the number of positive electrode plates, or may be the same.
The density of the positive electrode mixture is 4.3 g / cm ³ or more and 4.7 g / cm ³ or less.

The negative electrode mixture has the same structure as the conventional product. Specifically, it contains lead, which is a negative electrode active material, and reinforcing fibers.
The negative electrode plate is housed in a bag-shaped separator. Then, by alternately stacking the bag-shaped separator containing the negative electrode plate and the positive electrode plate, the separator is arranged between the positive electrode plate and the negative electrode plate. The positive electrode plate may be stored in the bag-shaped separator and alternately stacked with the negative electrode plate.

Further, each electrode plate group includes a positive electrode strap and a negative electrode strap that connect the positive electrode plate and the negative electrode plate of the laminated body at different positions in the width direction, and a positive electrode intermediate pole column and a negative electrode intermediate pole that rise from the positive electrode strap and the negative electrode strap, respectively. Has columns. The positive electrode strap and the negative electrode strap connect the ears of the positive electrode plate and the negative electrode plate, respectively. The positive electrode strap and the negative electrode strap arranged in the cell chambers at both ends in the cell arrangement direction are formed with positive electrode pole columns and negative electrode pole columns serving as external terminals, respectively, via small pieces.
The electrolytic solution is a sulfuric acid aqueous solution containing at least one of aluminum ions and lithium ions, sodium ions and lignin sulfonate (anionic polymer surfactant), and the total concentration of aluminum ions and lithium ions is 0. It is 01 mol / L or more and 0.30 mol / L or less, the sodium ion concentration is 50 ppm or more and 10000 ppm or less, and the concentration of the water-soluble polymer surfactant is 0.002% by mass or more and 0.5% by mass or less.

[Manufacturing method]
The lead-acid battery of the embodiment can be manufactured by, for example, the following method. A conventionally known method can be adopted other than the method for manufacturing the positive electrode plate.
First, as a kneaded product used when producing a positive electrode plate before chemical conversion, a kneaded product (wet paste) containing lead powder, dilute sulfuric acid, bismuth oxide, and water is produced. At that time, the density of the wet paste is adjusted to a value such that the density of the positive electrode mixture is 4.3 g / cm ³ or more and 4.7 g / cm ^{3 or less after chemical conversion.} The amount of bismuth oxide added is 0.03 parts by mass or more and 0.10 parts by mass or less with respect to 100 parts by mass of lead powder.
Next, the produced kneaded product is filled in a grid-like substrate of a current collector, aged, and then dried.
The density of the positive electrode mixture can also be adjusted by adjusting the mass of the solid content in the wet paste, the aging temperature of the wet paste, the filling amount of the wet paste in the grid-like substrate, and the like.
The above is the process of obtaining the positive electrode plate before chemical conversion.

Next, a laminate before chemical conversion is produced by using the obtained positive electrode plate before chemical conversion, the negative electrode plate before chemical conversion produced by a usual method, and a separator.
Next, a COS (cast-on-strap) casting device was used to form the pre-chemical laminate to form a positive electrode strap connecting the ears of the positive electrode plates and a negative electrode strap connecting the ears of the negative electrode plates. A positive electrode intermediate pole column, a negative electrode intermediate pole column, a positive electrode pole column, and a negative electrode pole column are formed. After forming them, the laminate is placed in each cell chamber of the battery case.
Next, by resistance welding the positive electrode intermediate pole columns or the negative electrode intermediate pole columns of the adjacent cell chambers, the adjacent cells are electrically connected in series. Next, the upper surface of the electric tank and the lower surface of the lid are melted by heat, the lid is placed on the electric tank, and the lid is fixed to the electric tank by heat welding. When the lid is placed on the battery case, the positive electrode pole and the negative electrode pole are passed through the through holes of the bushing insert-molded in the lid. After that, the positive electrode pole and the negative electrode pole pillar in a state of protruding from the through hole of the bushing are heated by a burner or the like and integrated with the bushing to form the positive electrode terminal and the negative electrode terminal.

After that, the total concentration of aluminum ions and lithium ions is 0.01 mol / L or more and 0.30 mol / L or less, and the sodium ion concentration is 50 ppm or more and 10000 ppm or less in the cell chamber through the liquid injection hole provided as a hole penetrating the lid. After injecting the sulfuric acid aqueous solution, the lead-acid battery assembly is completed by performing a normal step such as closing the injection hole. Then, after carrying out the electric tank chemical formation under normal conditions, lignin sulfonate is added to the electrolytic solution in a range of 0.002% by mass or more and 0.5% by mass or less. As a result, the lead storage battery of the present embodiment can be obtained.
Due to this battery formation, the lead powder held in the current collector is changed to the positive electrode active material, and the density of the positive electrode mixture becomes 4.3 g / cm ³ or more and 4.7 g / cm ³ or less.

[Action, effect]
According to the lead-acid battery of the present embodiment, the density of the positive electrode mixture is 4.3 g / cm ³ or more and 4.7 g / cm ³ or less, and the electrolytic solution contains at least one of aluminum ions and lithium ions, and aluminum ions and The electrolyte of a lead-acid battery containing 0.01 mol / L or more and 0.30 mol / L or less in total lithium ion concentration contains lignin sulfonate at a concentration of 0.002% by mass or more, and sodium of 50 ppm or more and 10,000 ppm or less. By containing ions, both the effect of suppressing dendrite short-circuit when used in a partially charged state and the effect of suppressing the decrease in water content in the electrolytic solution during high-temperature overcharging can be expected.
Further, since the density of the positive electrode mixture is 4.3 g / cm ³ or more and 4.7 g / cm ³ or less, the durability (life performance) of the positive electrode plate is high and the utilization efficiency (discharge capacity) of the active material is high. Can be compatible. When the density of the positive electrode mixture is 4.8 g / cm ³ or more, it is advantageous in terms of durability (life performance), but is disadvantageous in terms of utilization efficiency (discharge capacity) of the active material.

[Preparation of test battery]
As lead-acid batteries having the same structure as the lead-acid batteries of the embodiment, the lead-acid batteries of Samples No. 1-1 to No. 1-48 and No. 2-1 to No. 2-6 are conventionally known as described in the embodiments. It was prepared by the method of. Specifically, a Q-85 type lead-acid battery having a 20HR capacity of 61Ah and an operating voltage of 12V was produced.

[Preparation of positive electrode plate (before chemical conversion)]
<No.1-1 to No.1-14>
First, lead powder for storage batteries (a mixed powder of lead and lead oxide having a particle size of several μm to 30 μm, and the mixing ratio by mass ratio is lead: lead oxide = about 25:75) and polyester fiber. Tetron (registered trademark) and bismuth oxide were mixed to obtain a dry mixture.
Water was added to the obtained dry mixture and kneaded, and then dilute sulfuric acid was added and kneaded again to prepare a paste for forming a positive electrode mixture (wet paste). At that time, the amount of water to be added was adjusted so that the density of the wet paste was about 4.2 g / cm ³ . The value of the wet paste density was obtained by filling a stainless steel container having a known internal volume with the wet paste and dividing the mass of the filled wet paste by the volume of the container.

Next, this wet paste was filled in a grid-like substrate of a D size battery current collector (gravity cast substrate, 47 g / sheet, thickness about 1.3 mm) made of a Pb—Sn-based lead alloy, and dilute sulfuric acid was added. Was uniformly sprayed onto the surface filled with the wet paste at a pressure of 0.1 MPa, and then the current collector was passed through a preheat drying furnace to increase the water content of the wet paste after preheating and drying by about 10 mass. Adjusted to%.
Next, the current collector is left in an environment of a temperature of 40 ° C. ± 5 ° C. and a humidity of 95% ± 5% for 30 hours to mature the preheated wet paste, and then an environment of a temperature of 60 ° C. ± 5 ° C. The paste was dried by holding underneath for 8 hours. As a result, a positive electrode plate before chemical conversion was obtained.

<No.1-15 to No.1-34, No.2-1 to No.2-6>
By adjusting the amount of water to be added, the density of the wet paste was adjusted to about 4.3 g / cm ^3, and the water content of the wet paste after preheating and drying was adjusted to about 9.5% by mass. Except for this, the positive electrode plate before chemical conversion was obtained by the same method as No. 1-1 to No. 1-14.
<No.1-35 to No.1-48>
By adjusting the amount of water to be added, the density of the wet paste was adjusted to about 4.5 g / cm ^3, and the water content of the wet paste after preheating and drying was adjusted to about 8.5% by mass. Except for this, the positive electrode plate before chemical conversion was obtained by the same method as No. 1-1 to No. 1-14.

[Manufacturing of negative electrode plate (before chemical conversion)]
A paste for forming a negative electrode mixture prepared by a usual method is used as a grid-like substrate for a D size battery current collector (continuously cast substrate, 40 g / sheet, thickness: about 0.8 mm) made of a Pb—Sn-based lead alloy. The current collector was passed through a preheating and drying furnace under normal conditions. Next, the current collector is left in an environment of a temperature of 40 ° C. ± 5 ° C. and a humidity of 95% ± 5% for 30 hours to mature the filled paste, and then in an environment of a temperature of 60 ° C. ± 5 ° C. The paste was dried by holding in. As a result, a negative electrode plate before chemical conversion was obtained.

[Assembly of lead-acid battery]
First, in order to prepare a group of electrode plates for each lead-acid battery, 42 (7 × 6 cells) pre-chemical positive electrode plates produced by the above method and a pre-chemical negative electrode plate produced by the above method are produced. 2592 sheets (8 sheets x 6 cells x (48 + 6) sets) and the same number of bag-shaped separators as the negative electrode plates before chemical conversion were prepared.
Next, the negative electrode plate before chemical conversion is housed in a bag-shaped separator, and eight separators containing the negative electrode plate before chemical conversion and seven positive electrode plates before chemical conversion are alternately laminated to form seven positive electrode plates before chemical conversion. Six laminated bodies having eight negative electrode plates before chemical conversion were obtained for each sample.

Next, for each sample No., the obtained six laminates were used with a COS (cast-on-strap) casting device to supply molten metal (lead alloy) into the cavity, and the ears were placed on the lower side. By inserting the selvages of the laminated body in a state of facing toward, first, a positive electrode strap and a negative electrode strap for connecting the selvages were formed. Subsequently, small pieces and polar columns are formed on the negative electrode straps and the positive electrode straps arranged in the cell chambers at both ends in the arrangement direction, and the positive electrode intermediate pole columns and the negative electrode intermediate pole columns are formed on the other positive electrode straps and the negative electrode straps, respectively. Was formed. Next, they were placed in each of the six cell chambers of a polypropylene monoblock type battery case of the outer shape division M of "SBA S 0101".

Next, the positive electrode intermediate pole pillar and the negative electrode intermediate pole pillar facing each other with the partition wall partitioning the cell chambers of the battery case from each other were connected by resistance welding at the portion of the through hole provided in the partition wall. In this state, a group of electrode plates before chemical conversion is arranged in each cell of the battery case. The compression force of the electrode plate group was about 10 kPa.
By heat-welding the battery case and lid in this state by the method described in the embodiment, before the chemical formation of No. 1-1 to No. 1-48 and No. 2-1 to No. 2-6. Obtained a lead-acid battery.

Next, for the lead-acid batteries of No. 1-1 to No. 1-48 before chemical conversion, aluminum sulfate and / or aluminum sulfate and / or so as to have the ion concentrations shown in Tables 1 and 2 for each sample No. A dilute sulfuric acid electrolytic solution to which lithium sulfate was added was injected into each cell chamber of the battery case through the injection hole of the lid of the lead-acid battery before each chemical conversion. Then, after chemical conversion of the battery under normal conditions, sodium lignin sulfonate (water-soluble polymer surfactant) was added so as to have the concentrations shown in Tables 1 and 2, and No. 1 to No. 1 to No. Each .48 lead-acid battery was obtained.

For the lead-acid batteries of No. 2-1 to No. 2-6 before chemical conversion, dilute sulfuric acid to which aluminum sulfate, lithium sulfate, and sodium sulfate were added so as to have the ion concentration shown in Table 3 The electrolytic solution was injected into each cell chamber of the battery case through the injection hole of the lid of the lead-acid battery before each chemical conversion. Then, after chemical conversion of the battery under normal conditions, sodium lignin sulfonate (water-soluble polymer surfactant) was added to the concentration shown in Table 3 to obtain No. 2-1 to No. Each lead-acid battery of 2-6 was obtained.
In other words, the lead-acid batteries No. 2-1 to No. 2-6 have the same positive electrode plate before chemical conversion as the lead-acid batteries No. 1-19, and sodium lignin sulfonate in the electrolytic solution added after chemical conversion. However, it differs from the lead-acid battery of No. 1-19 in that sodium sulfate is added to the electrolytic solution and the sodium ion concentration is as shown in Table 3.

[Measurement of density]
For the positive electrode plate of each lead-acid battery, the density of the positive electrode mixture was measured by the following method.
The positive electrode plate was taken out from each lead-acid battery after the conversion of the battery case, washed with water and dried, and then the positive electrode mixture was scraped off from the positive electrode plate to make a powder. The obtained powder was set in a mercury press-fitting porosimeter, and the median pore diameter and density of the positive electrode mixture were measured by the mercury press-fitting method.

[Dendrite short confirmation test]
A dendrite short-circuit confirmation test was conducted for each lead-acid battery according to the following procedure.
First, each lead-acid battery is placed in an environment of 25 ° C. and discharged with a current (0.05C) for 20 hours until the voltage reaches 10.5V. Next, each lead-acid battery is placed in an environment of 40 ° C., a resistor of 499 ohms is connected to each lead-acid battery, and the lead-acid battery is left for 14 hours. Next, each lead-acid battery is returned to an environment of 25 ° C. and charged at a constant voltage under the conditions of 150A and 15V.
Next, each lead-acid battery was disassembled, the electrode plates arranged in the first and third cell chambers were taken out and disassembled, and a total of 16 (8 × 2) separators were visually observed. The number of separators with dendrite shorts (with short marks) was examined. The ratio (%) of the total number of sheets (16) was defined as the dendrite short ratio. That is, when two of the 16 separators have short marks, the dendrite short ratio is 2/16 × 100 = 13%.

[Test to check the amount of water reduction (high temperature overcharge test)]
For each lead-acid battery, a high-temperature overcharge test was carried out according to the following procedure with reference to SAE standard J240.
Each lead-acid battery was placed in a water tank whose water temperature was controlled to 75 ° C. ± 3 ° C., and discharging and charging under the following conditions were repeated 1920 times, and then the mass of each lead-acid battery was measured.
Discharge condition: 25A ± 0.1A for 4 minutes ± 1 second Charging condition: 14.8V ± 0.03V (current limit 25A ± 0.1A) for 10 minutes ± 3 seconds

In addition, every time the number of repetitions becomes 480 times, it is left in a water tank for 60 to 72 hours after charging, and it is judged discharge at 440 A (discharge for checking that the end-of-discharge voltage after 30 seconds is 7.2 V or more). However, water was not replenished.
For each lead-acid battery, the mass difference obtained by subtracting the mass measurement value before the test from the mass measurement value after the test is defined as the water reduction amount of each lead-acid battery, and the water reduction amount of the No. 1-19 lead-acid battery is 100. The relative value of the amount of water reduction was calculated.

[PSOC life test]
An idling stop life test of "SBA S 0101 (2014 version)" was carried out for each lead-acid battery.
Specifically, each lead-acid battery was placed in an environment (gas phase space) controlled at 25 ° C ± 2 ° C, the wind speed in the vicinity of the battery was set to 2.0 m / s or less, and discharging and charging were repeated under the following conditions. ..
Discharge condition: 54.9A ± 1A for 59.0 seconds ± 0.2 seconds, then 300A ± 1A for 1.0 seconds ± 0.2 seconds Discharge Condition: 14.00V ± 0.03V (Limited) Charging for 60.0 seconds ± 0.3 seconds with a current of 100.0 A ± 0.5 A)

Every time the number of repetitions reached 3600, the battery was left for 40 to 48 hours after charging, and then the repetition of discharging and charging was restarted. Further, the test was terminated when the voltage after discharging at 300 A ± 1 A for 1.0 second ± 0.2 seconds became less than 7.2 V, and the time up to that point was taken as the life. In addition, water was not replenished until the number of repetitions reached 30,000.
These measurements and test results are shown in Tables 1 to 3 below, along with the composition of the electrolyte for each sample. The life is a relative value with the value of the lead storage battery of No. 1-19 as 100.

As shown in Tables 1 and 2, the constituent requirements of one aspect of the present invention are "the density of the positive electrode mixture is 4.3 g / cm ³ or more" and "the electrolyte is aluminum ion and lithium ion. It contains at least one and the total concentration of aluminum ions and lithium ions is 0.01 mol / L or more and 0.30 mol / L or less. ”And“ It contains a polymer surfactant and the concentration of the polymer surfactant is 0. Lead-acid batteries that satisfy all of ".002 mass% or more" (listed as "Examples" in the table) have a low dendrite short-circuit ratio of 6 and a low water reduction (relative value) of 106 or less. , The life (relative value) is as long as 98 or more.

On the other hand, lead-acid batteries that do not meet at least one of the above three constituent requirements (those described as "comparative examples" in the table) are judged to pass "dendrite short ratio of 6 or less" and " It does not satisfy either "the amount of water reduction (relative value) is 110 or less" or "the life (relative value) is 98 or more".
In addition, among the lead-acid batteries that satisfy all of the above three constituent requirements, the lead-acid batteries of No. 1-19 and No. 1-37, which differ only in the density of the positive electrode mixture, have a density of 4.5 g / cm ³ The lead-acid battery of No. 1-37 has a longer life than the lead-acid battery of No. 1-19 having a ^{density of 4.3 g / cm 3.}

Further, as shown in Table 3, in addition to the above three constituent requirements, a lead-acid battery satisfying "the sodium ion concentration of the electrolytic solution is 50 ppm or more and 10000 ppm" (listed as "preferable example" in the table). ), The dendrite short-circuit ratio is 0, the amount of water reduction (relative value) is as small as 102 or less, and the life (relative value) is 100 or more.
The lead-acid battery of No. 1-19 has the same composition as No. 2-1 to No. 2-6 except that sodium sulfate is not added to the electrolytic solution (therefore, the sodium ion concentration is about 10 ppm). Although it is a storage battery, its dendrite short-circuit ratio is the same value (6%) as that of the No. 2-1 lead-acid battery in which the sodium ion concentration of the electrolytic solution is 40 ppm. Further, when the sodium ion concentration of the electrolytic solution is 11000 ppm, the PSOC life is slightly shorter than when it is 10,000 ppm or less. Therefore, when the electrolytic solution contains sodium ions, it can be seen that the sodium ion concentration is preferably in the range of 50 ppm or more and 10000 ppm or less.

Claims (3)

A cell chamber and a group of electrode plates stored together with an electrolytic solution in the cell chamber are provided, and the electrode plate group is between the negative electrode plates and the positive electrode plates arranged alternately, and between the negative electrode plate and the positive electrode plate. A lead-acid battery having a laminate composed of a separator arranged in
The positive electrode plate is composed of a current collector and a positive electrode mixture held on a grid-like substrate of the current collector.
The density of the positive electrode mixture is 4.3 g / cm ³ or more, and
The electrolytic solution contains at least one of aluminum ions and lithium ions and a polymer surfactant, and the total concentration of aluminum ions and lithium ions is 0.01 mol / L or more and 0.30 mol / L or less, which is high. A lead-acid battery having a concentration of a molecular surfactant of 0.002% by mass or more. The lead-acid battery according to claim 1, wherein the sodium ion concentration of the electrolytic solution is 50 ppm or more and 10000 ppm or less. The lead-acid battery according to claim 1 or 2, wherein the polymer surfactant is a lignin sulfonate.