JP6939565B2 - Lead-acid battery - Google Patents

Description

The present invention relates to a lead storage battery.

Lead-acid batteries are inexpensive, have a relatively high battery voltage, and can obtain a large amount of electric power. Therefore, lead-acid batteries are used in various applications other than cell starters for automobiles. The lead-acid battery includes a positive electrode containing lead dioxide, a negative electrode containing lead, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid.

In recent automobile applications, lead-acid batteries are often used in a state of charge (SOC) of about 90 to 70%, such as being exposed to an idle stop state. If the battery is continuously used in such a half-charged state, the charge acceptability is lowered due to the deactivation of the negative electrode active material called sulfation, and the deterioration of the battery is accelerated. This is because lead sulfate gradually crystallizes and loses electrochemical activity in a chronic undercharged state. Since crystalline lead sulfate is difficult to dissolve in the electrolyte, the polarization of the charging reaction of the negative electrode increases. By reducing the charge acceptability of the negative electrode, the charge capacity (charging efficiency) in a limited charging time becomes small, and it becomes difficult to recover the SOC. Therefore, the state of being charged halfway continues, the SOC further decreases, and the battery deteriorates.

Therefore, various improvements have been attempted to suppress the deactivation of the negative electrode active material by improving the charge acceptability of the negative electrode.
In Patent Document 1, in order to improve the charge acceptability of the negative electrode of a lead-acid battery, synthetic lignin (bisphenol sulfonic acid polymer condensate) having a molecular weight of 17,000 to 20,000 and carbon black are used as additives for the negative electrode. It has been proposed to use and. For the same purpose, in Patent Document 2, a formaldehyde condensate of scaly graphite and a sodium salt of bisphenol A aminobenzenesulfonic acid having a molecular weight of 15,000 to 20,000 and a sulfur content of 6 to 10% by mass is used. It has been proposed to be used for the negative electrode.

Japanese Unexamined Patent Publication No. 2006-196191 Japanese Unexamined Patent Publication No. 2013-41848

The formaldehyde condensate of bisphenol aminobenzenesulfonic acid and its sodium salt added to the negative electrode in Patent Document 1 and Patent Document 2 has a high molecular weight of 15,000 or more and 17,000 or more. When such a condensate is used, the surface of lead sulfate precipitated on the surface of the negative electrode is covered with the high molecular weight condensate, and the effective surface area of lead sulfate is reduced. Therefore, it is prevented that lead ions are eluted from lead sulfate into the electrolyte. Further, the surface of lead is covered with the condensate, the number of charge reaction sites on the negative electrode is reduced, and the charge acceptability is lowered. Charge acceptability tends to decrease as the temperature decreases.

An object of the present invention is to suppress a decrease in charge acceptability in a lead storage battery.
One aspect of the present invention includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid.
The negative electrode contains a condensate of bisphenols, aminobenzenesulfonic acids and formaldehyde, and a negative electrode active material.
The weight average molecular weight of the condensate is 5,000 to 13,000.
The electrolyte relates to a lead-acid battery comprising at least one selected from the group consisting of aluminum ions and titanium ions.

According to the above aspect of the present invention, it is possible to provide a lead storage battery in which a decrease in charge acceptability is suppressed.

Although the novel features of the present invention are described in the appended claims, the present invention is further described in the following detailed description with reference to the drawings, in combination with other objects and features of the present invention, both in terms of structure and content. It will be well understood.

It is a perspective view which cut out a part of the lead storage battery which concerns on one Embodiment of this invention. It is a front view of the positive electrode in the lead storage battery of FIG. It is a front view of the negative electrode in the lead storage battery of FIG.

The lead-acid battery according to an embodiment of the present invention includes a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid. The negative electrode contains a condensate of bisphenols, aminobenzenesulfonic acids and formaldehyde, and a negative electrode active material. The weight average molecular weight of this condensate is 5,000 to 13,000. The electrolyte further comprises at least one selected from the group consisting of aluminum ions and titanium ions.

In the vicinity of the surface of lead sulfate precipitated on the negative electrode, hard crystals are likely to be formed by sulfation, and the formation of hard crystals hinders the redissolution of lead sulfate. When a condensate of bisphenols, aminobenzenesulfonic acids and formaldehyde is added to the negative electrode, the precipitated lead sulfate is coated with the condensate to suppress sulfation. However, when the condensate has a high molecular weight such as 15,000 or more or 17,000 or more, most of the surface of lead sulfate is covered by the condensate, so that the effective surface area of lead sulfate becomes small. .. In addition, the presence of a high molecular weight condensate on the surface of the negative electrode also covers the surface of active lead, reducing the effective surface area of lead. As a result, the elution of lead ions from lead sulfate is hindered, and the number of reaction sites responsible for the charging reaction on the negative electrode is reduced, so that the charging acceptability is lowered.

In the present invention, a condensate having a relatively low molecular weight having a weight average molecular weight of 5,000 to 13,000 is used, and the electrolyte contains at least one cation selected from the group consisting of aluminum ions and titanium ions, thereby causing a negative electrode. The surface of the lead sulfate precipitated above is appropriately covered with the condensate, the effective surface area of the lead sulfate can be increased as compared with the conventional case, and sulfation can be suppressed. Therefore, it is possible to maintain a state in which lead ions are easily eluted from lead sulfate. Further, since the effective surface area of lead on the negative electrode can be increased as compared with the conventional case, the charging reaction site can be maintained. Therefore, the charge acceptability can be improved.

Sulfation of lead sulfate is suppressed by including at least one cation selected from the group consisting of aluminum ions and titanium ions in the electrolyte. The reason is not clear, but it is suppressed that cations are adsorbed on the surface of lead sulfate precipitated on the negative electrode and the particle size of lead sulfate becomes excessively large, and crystallization on the surface of lead sulfate is suppressed. it is conceivable that. It is considered that the above cation does not inhibit the elution of lead ions. By using a condensate having a relatively small molecular weight, the effective surface area of lead sulfate is increased, and the chance of contact between the above-mentioned cation and lead sulfate is increased. Therefore, more cations are adsorbed on lead sulfate, and the effect of suppressing the sulfation of the above cations on lead sulfate becomes stronger.

By interacting with lead ions, the condensate inhibits the movement of lead ions during charging. It is speculated that this interaction between the condensate and lead ions occurs between the aroma ring near the end of the condensate near the exposed lead sulfate and the lead ions. Here, since the cation has a strong action with the condensate, it is possible to suppress the inhibition of the movement of the lead ion by the action of the condensate and the lead ion. As the molecular weight of the condensate decreases, the condensate covers the lead sulfate surface more uniformly, thus increasing the exposure ratio of the aromatic ring that acts with the cation. As a result, the action of the condensate and the cation is strengthened, the action of the condensate and the lead ion is weakened, and the lead ion is easily transferred, so that the charge acceptability can be improved.
The charge acceptability tends to decrease at a low temperature as compared with the room temperature, but in the present invention, high charge acceptability can be ensured not only at room temperature but also at low temperature.

In the present specification, the room temperature means, for example, a temperature of 20 ° C. to 35 ° C. Further, the low temperature means a temperature of 5 ° C. or lower or 0 ° C. or lower (for example, −20 ° C. to + 5 ° C., or −20 ° C. to 0 ° C.).

Hereinafter, the lead-acid battery according to the embodiment of the present invention will be described in more detail with reference to the drawings as appropriate.
(Negative electrode)
The negative electrode of a lead-acid battery generally includes a negative electrode grid (such as an expanded grid or a cast grid) and a negative electrode mixture held in the negative electrode grid. The negative electrode active material and the above condensate are usually contained in this negative electrode mixture. Since the negative electrode is generally plate-shaped, it is also called a negative electrode plate.

Examples of the material of the negative electrode lattice include lead or a lead alloy. The lead alloy may contain, for example, Ba, Ag, Ca, Al, Bi, Sb, and / or Sn. Among them, a lead alloy containing Ca and / or Sn is preferable, and from the viewpoint of mechanical strength and the like, it is also preferable to use a lead alloy containing at least Ca. In the lead alloy, the Ca content may be 0.03 to 0.10% by mass, and the Sn content may be 0.2 to 0.6% by mass. The negative electrode lattice may have a plurality of lead alloy layers having different compositions, if necessary.

The negative electrode active material develops its capacity by a redox reaction. Lead (such as spongy lead) is used as the negative electrode active material. The negative electrode active material in the charged state is spongy lead, but the unchemicald negative electrode is usually produced by using lead powder. When preparing the negative electrode, the lead powder may contain lead oxide.

The bisphenols constituting the condensate are not particularly limited as long as they have a structure in which two phenol units are linked. Examples of bisphenols include, in addition to biphenol, compounds having a skeleton in which two phenol units such as bisphenol A, bisphenol F, and bisphenol S are linked via a linking group. Examples of the linking group include an alkylene group (or an alkylidene group) such as methylene, ethylene and dimethylmethylene group; a sulfonyl group and the like. Substituents may be further added to the phenol unit or the linking group. The condensate contains units derived from bisphenols. As the condensate, one kind of bisphenols may be used, or two or more kinds of bisphenols may be used.

Examples of the aminobenzene sulfonic acids constituting the condensate include aminobenzene sulfonic acids and salts thereof. In the aminobenzenesulfonic acid, the positions of the amino group and the sulfonic acid group may be any of the o-position, the m-position or the p-position, but the p-position is preferable. Examples of the aminobenzenesulfonic acid salt include alkali metal salts such as sodium salt and potassium salt, and ammonium salt. The condensate contains units derived from aminobenzene sulfonic acids. As the condensate, one kind of aminobenzene sulfonic acid may be used, or two or more kinds of aminobenzene sulfonic acid may be used.

In the condensate, the molar ratio of the unit derived from bisphenols to the unit derived from aminobenzene sulfonic acids is, for example, 1.0: 0.3 to 1.0: 0.7, 1.0: It may be 0.3 to 1.0: 0.6.

The condensate contains a sulfonic acid group derived from aminobenzene sulfonic acids or a derivative group thereof (including a salt; hereinafter, a derivative group derived from the sulfonic acid group is simply referred to as a sulfonic acid group). The sulfonic acid group easily traps lead ions eluted from lead sulfate during charging and inhibits the movement of lead ions. From this point of view, it is preferable that the content of the sulfonic acid group in the condensate is small. The content of the sulfonic acid group can be confirmed by the sulfur content in the condensate. The sulfur content in the condensate is preferably 8% by mass or less, and may be 3 to 6% by mass or 3 to 5.5% by mass. When the weight average molecular weight of the condensate is 5,000 to 13,000 and the sulfur content is in the above range, the dispersibility of the condensate is particularly improved, and the lead sulfate surface is uniformly covered with the condensate, so that charging is possible. Great effect of improving acceptability.

In lead-acid batteries, the sulfur content in the condensate is determined using ICP emission spectrometry and ion chromatography. More specifically, first, the negative electrode is taken out from the lead storage battery, the negative electrode mixture is scraped off and washed with water, and the washed liquid is recovered. The negative electrode active material is obtained by vacuum drying this liquid, and the mass of the negative electrode active material is measured. The concentrations of S, Pb, and Ba in the negative electrode active material are determined by ICP emission analysis, and the concentrations of PbSO ₄ and BaSO ₄ are calculated. The negative electrode active material is dissolved in a predetermined amount of water, and the concentration of _{SO 4 is calculated by ion chromatography.} The concentration of the SO ₄ corresponds to the total concentration of H ₂ SO _4, PbSO ₄ and BaSO _4. From _{the concentration of SO 4,} the concentration of PbSO ₄ and BaSO ₄ calculated above, and the mass of the negative electrode active material measured above, the total of _{H 2} SO ₄ , PbSO ₄ and BaSO _{4 contained in the negative electrode active material.} The mass is obtained, and the mass of the condensate is obtained by subtracting this total mass from the mass of the negative electrode active material. _{By subtracting the concentration of SO 4} obtained by ion chromatography from the concentration of S element obtained by ICP emission spectrometry, the concentration of S element in the condensate was obtained, and from this concentration and the mass of the condensate, the concentration in the condensate was obtained. The sulfur content of is determined.

The content of the condensate in the negative electrode is, for example, 0.01 to 2 parts by mass, 0.05 to 1.5 parts by mass, or 0.05 to 1 part by mass with respect to 100 parts by mass of the negative electrode active material (lead). It is preferably parts by mass. When the content of the condensate is in such a range, the effect of improving charge acceptability can be easily obtained.

The negative electrode (particularly the negative electrode mixture) may further contain a shrink-proofing agent (such as barium sulfate), a conductive agent (such as a conductive carbonaceous material such as carbon black), and / or a binder (such as a polymer binder). good. Further, the negative electrode may contain other known additives, if necessary.

The negative electrode can be formed by filling or applying a negative electrode mixture paste to a negative electrode lattice and drying it to prepare an unchemicald negative electrode, and further performing a chemical conversion treatment. The negative electrode mixture paste contains sulfuric acid and / or water as a dispersion medium in addition to the constituent components of the negative electrode mixture (such as the negative electrode active material and the above-mentioned condensate).

The drying step may be an aging drying step of drying at a temperature and humidity higher than room temperature. The drying step can be performed under known conditions.
The chemical conversion treatment can be carried out by charging the lead-acid battery in the battery case with the positive electrode and the negative electrode before chemical conversion immersed in an electrolyte containing sulfuric acid. If necessary, the chemical conversion treatment can be performed before assembling the battery or the electrode plate group.

(Positive electrode)
The positive electrode of a lead-acid battery generally includes a positive electrode grid (such as an expanded grid or a cast grid) and a positive electrode active material (or a positive electrode mixture) held in the positive electrode grid. Since the positive electrode is generally plate-shaped, it is also called a positive electrode plate.

As the material of the positive electrode lattice, lead or a lead alloy exemplified for the negative electrode lattice can be exemplified. From the viewpoint that high corrosion resistance and mechanical strength can be easily obtained, it is preferable to use a lead alloy containing Ca and / or Sn. In the lead alloy, the Ca content may be 0.01 to 0.1% by mass, and the Sn content may be 0.05 to 3% by mass. The positive electrode lattice may have a plurality of lead alloy layers having different compositions, if necessary. For example, it is preferable to form a lead alloy layer containing Sb in the portion that holds the positive electrode active material from the viewpoint of suppressing deterioration of the positive electrode active material. The content of Sb in the positive electrode lattice may be, for example, 0.001 to 0.002% by mass.

The positive electrode active material develops its capacity by a redox reaction. _{Lead oxide (PbO 2} ) is used as the positive electrode active material. The positive electrode active material is usually used in powder form.
The positive electrode mixture may contain a conductive agent (such as a conductive carbonaceous material such as carbon black) and / or a binder (such as a polymer binder) in addition to the positive electrode active material. The positive electrode may contain a known additive, if necessary.
The positive electrode can be formed according to the case of the negative electrode.

(Separator)
Examples of the separator include a microporous membrane or a fiber sheet (or mat). As the polymer material constituting the microporous membrane or the fiber sheet, one having acid resistance is preferable, and polyolefins such as polyethylene and polypropylene can be exemplified. The fiber sheet may be formed of polymer fibers (fibers formed of the above-mentioned polymer material) and / or inorganic fibers such as glass fibers.
The separator may optionally contain a filler and / or an additive such as carbon.

(Electrolytes)
The electrolyte contains sulfuric acid and further contains at least one cation selected from the group consisting of aluminum ions and titanium ions. Of these cations, aluminum ions are preferred.

The concentration of the above cation in the electrolyte is, for example, 1 to 50 mmol / L, preferably 5 to 50 mmol / L, and may be 10 to 40 mmol / L in the case of aluminum ions. In the case of titanium ions, it is 0.1 to 50 mmol / L, preferably 1 to 40 mmol / L, and may be 1 to 10 mmol / L. When the concentration of the cation is in such a range, the effect of suppressing sulfation is further enhanced.

The electrolyte may optionally contain a solid titanium compound. Titanium compounds include, for example, metatitanic acid, titanic acid hydrate and / or titanate.

The density of the electrolyte is, for example, 1.10 to 1.35 g / cm ³ , preferably 1.20 to 1.35 g / cm ^3. In the present specification, the density of the electrolyte is the density at 20 ° C. Regarding the density of the electrolyte in the battery, it is preferable that the density of the electrolyte in the fully charged battery (SOC is 99% or more) is in the above range. The fully charged battery is a ready-made, fully charged battery.

A lead-acid battery can be produced by accommodating a group of plates and an electrolyte in a battery case (battery). The electrode plate group can be produced by superimposing a plurality of positive electrodes and a plurality of negative electrodes so that the positive electrodes and the negative electrodes alternate with each other with a separator interposed therebetween. The separator may be arranged so as to be interposed between the positive electrode and the negative electrode, and a bag-shaped separator may be used, or a sheet-shaped separator may be folded in half (U-shaped) to sandwich one electrode and the other. It may be overlapped with the electrode. A plurality of electrode plates may be housed in the battery case.

FIG. 1 is a partially cutaway perspective view of a lead storage battery according to an embodiment of the present invention. FIG. 2 is a front view of the positive electrode of FIG. 1, and FIG. 3 is a front view of the negative electrode of FIG.
The lead-acid battery 1 contains a electrode plate group 11 and an electrolyte (not shown), which are housed in a battery case 12. More specifically, the electric tank 12 is divided into a plurality of cell chambers 14 by a partition wall 13, and each cell chamber 14 houses one electrode plate group 11 and also contains an electrolyte. The electrode plate group 11 is formed by laminating a plurality of positive electrodes 2 and 3 through a separator 4.

The positive electrode grid 21 of the positive electrode 2 is provided with ears 22, and the positive electrode 2 is connected to the positive electrode connecting member 10 via the ears 22. The positive electrode connecting member 10 includes a positive electrode shelf 6 connected to the ear 22 of the positive electrode lattice 21, and a positive electrode connecting body 8 or a positive electrode column provided on the positive electrode shelf 6. Similarly, the negative electrode lattice 31 of the negative electrode 3 is provided with an ear 32, and the negative electrode 3 is connected to the negative electrode connecting member 9 via the ear 32. The negative electrode connecting member 9 includes a negative electrode shelf 5 connected to the ear 32 of the negative electrode lattice 31, and a negative electrode column 7 or a negative electrode connecting body provided on the negative electrode shelf 5. In the illustrated example, the positive electrode connecting body 8 is connected to the positive electrode shelf 6 at one end of the electric tank 12, and the negative electrode column 7 is connected to the negative electrode shelf 5. At the other end of the battery case 12, the positive electrode shelf 6 is arranged so that the positive electrode column is connected, and the negative electrode shelf 5 is connected to the negative electrode connector.

In each cell, the positive electrode shelf, the negative electrode shelf, and the entire electrode plate group are immersed in the electrolyte.
A lid 15 provided with a positive electrode terminal 16 and a negative electrode terminal 17 is attached to the opening of the battery case 12. The positive electrode connecting body 8 is connected to the negative electrode connecting body connected to the negative electrode shelf 5 of the electrode plate group 11 in the adjacent cell chamber 14 through a through hole provided in the partition wall 13. As a result, the electrode plate group 11 is connected in series with the electrode plate group 11 in the adjacent cell chamber 14. At one end of the battery case 12, the negative electrode column 7 is connected to the negative electrode terminal 17, and at the other end, the positive electrode column is connected to the positive electrode terminal 16. An exhaust plug 18 having an exhaust port for discharging the gas generated inside the battery to the outside of the battery is attached to the liquid injection port provided on the lid 15.

The positive electrode 2 includes a positive electrode lattice 21 having ears 22 and a positive electrode active material layer (or positive electrode mixture layer) 24 held by the positive electrode lattice 21. The positive electrode lattice 21 is an expanding lattice consisting of an expanding mesh 25 holding the positive electrode active material layer 24, a frame bone 23 provided at the upper end of the expanding network 25, and an ear 22 connected to the frame bone 23.

Similarly, the negative electrode 3 includes a negative electrode lattice 31 having ears 32 and a negative electrode active material layer (or negative electrode mixture layer) 34 held by the negative electrode lattice 31. The negative electrode lattice 31 is an expanding lattice consisting of an expanding mesh 35 holding the negative electrode active material layer 34, a frame bone 33 provided at the upper end of the expanding network 35, and an ear 32 connected to the frame bone 33.

The positive electrode connecting member 10 can be formed of lead or a lead alloy exemplified as the material of the positive electrode lattice. The negative electrode connecting member 9 can be formed of lead or a lead alloy exemplified as the material of the negative electrode lattice.

Hereinafter, the present invention will be specifically described based on Examples and Comparative Examples, but the present invention is not limited to the following Examples.

Example 1
(1) Preparation of positive electrode A positive electrode as shown in FIG. 2 was prepared by the following procedure.
A positive electrode paste was obtained by mixing the raw material lead oxide powder, water and dilute sulfuric acid (density 1.40 g / cm ³ ) at a mass ratio of 100: 15: 5.

A base material sheet made of Pb-0.06% by mass Ca-1.6% by mass Sn alloy obtained by a casting method and a lead alloy foil containing Sb were overlaid and rolled. As a result, the lead alloy foil was pressure-bonded onto the base material sheet to obtain a composite sheet having a lead alloy layer containing Sb having a thickness of 20 μm on one side of the base material layer having a thickness of 1.1 mm. The part where the lead alloy foil is crimped to the base material sheet is only the part that forms the expanded mesh in the expand processing described later, and the central part that forms the ear 22 and the frame bone 23 of the positive electrode lattice 21 in the base material sheet. The lead alloy foil was not crimped.

After forming a predetermined slit in the composite sheet, the slit was expanded to form an expanded mesh 25, and an expanded lattice body was obtained (expanded processing). Since the central portion of the composite sheet is used for the portion forming the ear 22 and the frame bone 23 of the positive electrode lattice 21 described later, it was not expanded.

The expanded mesh 25 was filled with the positive electrode paste and cut into a plate shape having the ears 22 of the positive electrode lattice 21. This was aged and dried to obtain an unchemicald positive electrode (length: 115 mm, width: 137.5 mm).

(2) Preparation of Negative Electrode A negative electrode as shown in FIG. 3 was prepared by the following procedure.
Raw materials Lead powder, condensate of bisphenol A, sodium p-aminobenzenesulfonic acid and formaldehyde, water, dilute sulfuric acid (density 1.40 g / cm ³ ), shrink-proofing agent (barium sulfate), and conductive material (carbon black) Was mixed to obtain a negative mixture paste. The amounts of the condensate, water, dilute sulfuric acid, shrink proofing agent and conductive material were 0.1 parts by mass, 12 parts by mass and 7.0 parts by mass, respectively, with respect to 100 parts by mass of the negative electrode active material (Pb). It was set to 0 parts by mass and 0.1 parts by mass. The weight average molecular weight Mw of the condensate was 5,000, and the sulfur content was 5.1% by mass.

A base material sheet made of Pb-0.07% by mass Ca-0.25% by mass Sn alloy obtained by a casting method is rolled to a thickness of 0.7 mm, and this base material sheet is expanded by the same method as described above. bottom. The expanded mesh was filled with the negative electrode mixture paste, and an unchemicald negative electrode (length: 115 mm, width 137.5 mm) was obtained by the same method as described above.

(3) Preparation of cell A cell (test cell) was prepared by the following procedure.
The positive electrode and the negative electrode prepared in the above (1) and (2) were cut into a size of 60 mm in length × 40 mm in width, respectively, and one negative electrode and two positive electrodes were prepared. A group of electrode plates was formed by laminating the negative electrode in a state of being sandwiched between two positive electrodes via a separator (a microporous film made of polyethylene, a base thickness of 0.2 mm and a width of 44 mm). At this time, the separator was arranged so as to sandwich the negative electrode between the two folds.

The obtained electrode plate group was sandwiched between acrylic plates from both sides and fixed. Next, a lead rod was welded to each of the negative electrode and the two positive electrodes to obtain a negative electrode terminal and a positive electrode terminal, respectively. It was placed in a container made of acrylic resin, and a predetermined amount of a sulfuric acid aqueous solution having ^{a density of 1.20 g / cm 3 was injected to carry out chemical conversion.} The aqueous sulfuric acid solution in the cell used for the chemical conversion was removed, and a new aqueous sulfuric acid solution in which aluminum sulfate was dissolved was injected. At this time, the final density of the electrolyte in the cell ^{was adjusted to 1.28 g / cm 3} , and the final aluminum ion concentration was adjusted to the values shown in Table 1. In this way, a test cell (1.25Ah, 2V) was prepared.

(4) Evaluation The charge acceptability was evaluated using the test cell prepared in (3) above. The 1.0C of the test cell was calculated from the theoretical capacity of each test cell.
Under the following conditions, the SOC of the test cell after chemical conversion was adjusted and charged. Charge acceptability was compared by the amount of electricity for 10 seconds after the start of charging.
Discharge (SOC adjustment): Constant current, 0.2C, 30 minutes Pause: 12 hours Charging (charge acceptability): Constant current (3C) -Constant voltage (2.4V, maximum current 3C), 60 seconds Temperature: 25 ° C Or -10 ° C

Example 2
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 7,000, sulfur content 4.8% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Examples 3-5
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 9,000, sulfur content 5.0% by mass) was used. The negative electrode and the test cell were prepared in the same manner as in Example 1 except that the amount of the condensate was adjusted so as to be the amount shown in Table 1 with respect to 100 parts by mass of the negative electrode active material (lead). Then, the same evaluation as in Example 1 was performed.

Example 6
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 11,000, sulfur content 6.8% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Example 7
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 12,000, sulfur content 5.2% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Example 8
A test cell was prepared in the same manner as in Example 7 except that the final aluminum ion concentration in the electrolyte in the battery was adjusted to 40 mmol / L. Then, the same evaluation as in Example 1 was performed.

Example 9
The sulfuric acid aqueous solution in the cell used for chemical conversion was removed, and a new sulfuric acid aqueous solution in which titanium sulfate was dissolved was injected. The final density of the electrolyte in the cell was 1.28 g / cm ³ , and the final titanium. A test cell was prepared in the same manner as in Example 7 except that the ion concentration was adjusted to the value shown in Table 1. Then, the same evaluation as in Example 1 was performed.

Example 10
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 13,000, sulfur content 6.0% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Comparative Example 1
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 17,000, sulfur content 7.5% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Comparative Example 2
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 4,000, sulfur content 5.6% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Comparative Example 3
In (2) of Example 1, as a condensate, a condensate of bisphenol A, a sodium salt of p-aminobenzenesulfonic acid, and formaldehyde (weight average molecular weight Mw: 15,000, sulfur content 6.8% by mass) was used. A negative electrode and a test cell were prepared in the same manner as in Example 1 except that they were used. Then, the same evaluation as in Example 1 was performed.

Comparative Example 4
The sulfuric acid aqueous solution in the cell used for chemical conversion was removed, and a new sulfuric acid aqueous solution in which titanium sulfate was dissolved was injected. The final density of the electrolyte in the cell was 1.28 g / cm ³ , and the final titanium. A test cell was prepared in the same manner as in Comparative Example 1 except that the ion concentration was adjusted to the value shown in Table 1. Then, the same evaluation as in Example 1 was performed. The aluminum ion concentration of the electrolyte in the cell is 0 mmol / L.

Comparative Example 5
A test cell was prepared in the same manner as in Example 7 except that the aqueous sulfuric acid solution was used as an electrolyte without adding aluminum sulfate. Then, the same evaluation as in Example 1 was performed. The aluminum ion concentration of the electrolyte in the cell is 0 mmol / L.

Comparative Example 6
A test cell was prepared in the same manner as in Comparative Example 1 except that the aqueous sulfuric acid solution was used as an electrolyte without adding aluminum sulfate. Then, the same evaluation as in Example 1 was performed. The aluminum ion concentration of the electrolyte in the cell is 0 mmol / L.

The results of Examples and Comparative Examples are shown in Table 1. Examples 1 to 10 are A1 to A10, and Comparative Examples 1 to 6 are B1 to B6. The Al ion concentration is the concentration of Al ions in the electrolyte in the cell. The Ti ion concentration is the Ti ion concentration in the electrolyte in the cell. The charge acceptability was expressed as a ratio when the value in Comparative Example 1 was set to 100.

As shown in Table 1, when the weight average molecular weight of the condensate is in the range of 5,000 to 13,000 and the electrolyte contains aluminum ions or titanium ions, the weight average molecular weight is 15,000 or 17,000. Compared with the case where a certain condensate is used or when the electrolyte does not contain aluminum ions or titanium ions, the charge acceptability is greatly improved. When the weight average molecular weight of the condensate is 12,000, the effect of aluminum ions and titanium ions is larger than that when the condensate having a weight average molecular weight of 17,000 is used, and a synergistic effect can be confirmed. Charge acceptability is improved not only at room temperature (25 ° C.) but also at low temperatures (-10 ° C.).

Although the present invention has described preferred embodiments at this time, such disclosures should not be construed in a limited way. Various modifications and modifications will undoubtedly become apparent to those skilled in the art belonging to the present invention by reading the above disclosure. Therefore, the appended claims should be construed to include all modifications and modifications without departing from the true spirit and scope of the invention.

The lead-acid battery according to the present invention has excellent charge acceptability, especially in a use mode in which charging and discharging are repeated in a half-charged state. Therefore, it is suitably used for vehicles equipped with an idle stop system and a regenerative braking system.

1 Lead storage battery, 2 positive electrode, 3 negative electrode, 4 separator, 5 negative electrode shelf, 6 positive electrode shelf, 7 negative electrode column, 8 positive electrode connecting body, 9 negative electrode connecting member, 10 positive electrode connecting member, 11 electrode group, 12 battery case, 13 Partition, 14 cell chamber, 15 lid, 16 positive electrode terminal, 17 negative electrode terminal, 18 exhaust plug, 21 positive electrode lattice, 22, 32 ears, 23, 33 frame bone, 24 positive electrode active material layer, 25, 35 expanded mesh, 31 negative electrode Lattice, 34 Negative electrode active material layer

Claims (4)

It contains a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid.
The negative electrode contains a condensate of bisphenols, aminobenzenesulfonic acids and formaldehyde, and a negative electrode active material.
The weight average molecular weight of the condensate is 5,000 to 13,000.
A lead-acid battery, wherein the electrolyte comprises at least one selected from the group consisting of aluminum ions and titanium ions. The bisphenols contain bisphenol A and
The lead storage battery according to claim 1, wherein the aminobenzenesulfonic acids are at least one selected from the group consisting of aminobenzenesulfonic acids and aminobenzenesulfonic acids. The lead-acid battery according to claim 1 or 2, wherein the sulfur content in the condensate is 3 to 6% by mass. The lead-acid battery according to any one of claims 1 to 3, wherein the content of the condensate in the negative electrode is 0.05 to 1 part by mass with respect to 100 parts by mass of the negative electrode active material.

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