WO2016121327A1

WO2016121327A1 - Lead storage cell

Info

Publication number: WO2016121327A1
Application number: PCT/JP2016/000223
Authority: WO
Inventors: 武澤　秀治; 森川　有紀
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2015-01-30
Filing date: 2016-01-18
Publication date: 2016-08-04
Also published as: JP6729397B2; JPWO2016121327A1

Abstract

To provide a lead storage cell having high charge acceptance and in which the decrease in the negative electrode utilization rate is minimized. The lead storage cell 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 electrolyte further contains titanium ions and aluminum ions. The titanium ion concentration in the electrolyte is less than 1.00 mmol/L and the aluminum ion concentration in the electrolyte is less than 10.0 mmol/L. The lead storage cell may also contain a solid titanium compound disposed so as to be in contact with the electrolyte.

Description

Lead acid battery

The present invention relates to lead-acid batteries, and particularly to improvements in electrolytes.

Lead-acid batteries are inexpensive, have a relatively high battery voltage, and provide high power, so they are used in various applications in addition to 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 mid-charging states where the state of charge (SOC) is about 90% to 70%, such as being exposed to an idle stop state. If the battery continues to be used in such a half-charged state, the charge acceptability decreases due to the deactivation of the negative electrode active material called sulfation, and the deterioration of the battery accelerates. 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 negative electrode charging reaction increases. When the charge acceptability of the negative electrode is reduced, the charge capacity (charge efficiency) in a limited charge time is reduced, and the SOC is difficult to recover. Therefore, the halfway charge state continues, the SOC decreases further, and the battery deteriorates.

Therefore, various improvements have been attempted to suppress the deactivation of the negative electrode active material by improving the charge acceptance of the negative electrode or increasing the charging efficiency.
Patent Document 1 discloses that charging efficiency is improved by adding a predetermined concentration of aluminum ion, selenium ion, titanium ion or the like to the electrolyte, and deterioration of the active material is suppressed. In Patent Document 1, the concentration of aluminum ions in the electrolyte is 10 mmol / L to 300 mmol / L, and the concentration of titanium ions is 1 mmol / L to 100 mmol / L.

International Publication No. 2007/036979 Pamphlet

It is considered that when aluminum ions, titanium ions or the like are added to the electrolyte as in Patent Document 1, it acts on the negative electrode and high charge acceptability can be obtained. However, when an electrolyte containing aluminum ions at a concentration as in Patent Document 1 is used, it is becoming clear that the utilization factor of the negative electrode is lowered. Further, even if titanium ions are added to the electrolyte so as to have the concentration described in Patent Document 1, the effect of improving charge acceptability commensurate with the amount added cannot be obtained, and the utilization factor of the negative electrode also decreases.

An object of the present invention is to provide a lead-acid battery that has high charge acceptability and suppresses a decrease in the utilization factor of the negative electrode.

One aspect of the present invention is a lead acid battery including a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid,
The electrolyte further includes titanium ions and aluminum ions,
The concentration of the titanium ions in the electrolyte is less than 1.00 mmol / L;
The concentration of the aluminum ions in the electrolyte relates to a lead-acid battery that is less than 10.0 mmol / L.

According to the present invention, in the lead storage battery, it is possible to suppress a decrease in the utilization factor of the negative electrode while ensuring high charge acceptability.

It is the schematic perspective view which notched some lead acid batteries concerning one embodiment of the present invention. It is a front view of the positive electrode plate in the lead acid battery of FIG. It is a front view of the negative electrode plate in the lead acid battery of FIG.

The lead storage battery according to the 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. Here, the electrolyte further contains titanium ions and aluminum ions, the concentration of titanium ions in the electrolyte is less than 1.00 mmol / L, and the concentration of aluminum ions in the electrolyte is less than 10.0 mmol / L. .

When the titanium ion concentration and / or the aluminum ion concentration in the electrolyte is higher than the above range, the effect of improving the charge acceptability corresponding to the concentration cannot be obtained, and the utilization factor of the negative electrode decreases. On the other hand, in the present embodiment, the concentration of titanium ions and aluminum ions in the electrolyte is within the above ranges, so that the crystal growth (that is, sulfation) of lead sulfate is suppressed and the solubility of lead ions in the electrolyte is suppressed. Therefore, a decrease in the utilization factor of the negative electrode can be suppressed. In addition, since the deactivation of the negative electrode active material due to sulfation can be suppressed, high charge acceptability of the negative electrode can be ensured.

The concentration of titanium ions in the electrolyte may be less than 1.00 mmol / L, preferably 0.97 mmol / L or less, and more preferably 0.95 mmol / L or less. The concentration of titanium ions in the electrolyte is preferably 0.08 mmol / L or more or 0.10 mmol / L or more, and may be 0.50 mmol / L or more from the viewpoint of further improving charge acceptance. These lower limit values and upper limit values can be arbitrarily combined. The concentration of titanium ions in the electrolyte may be, for example, 0.08 mmol / L to 0.97 mmol / L, or 0.10 mmol / L to 0.95 mmol / L.

The concentration of aluminum ions in the electrolyte may be less than 10.0 mmol / L, preferably 9.7 mmol / L or less, and more preferably 9.5 mmol / L or less. The concentration of aluminum ions in the electrolyte is preferably 0.8 mmol / L or more or 1.0 mmol / L or more. These lower limit values and upper limit values can be arbitrarily combined. The concentration of aluminum ions in the electrolyte may be, for example, 0.8 mmol / L to 9.7 mmol / L, or 1.0 mmol / L to 9.5 mmol / L.

In addition, the density | concentration of the titanium ion in an electrolyte and the density | concentration of aluminum ion can be made into the value in 20 degreeC, for example. The respective concentrations of titanium ions and aluminum ions are preferably concentrations in the electrolyte of the lead-acid battery in the initial state (for example, a lead-acid battery at the time of shipment or sale after break-in / discharge).

Hereinafter, the lead storage battery according to the embodiment of the present invention will be described in more detail with reference to the drawings as appropriate. (Positive electrode)
A positive electrode of a lead storage battery generally includes a positive electrode lattice (such as an expanded lattice or a cast lattice) and a positive electrode active material (or positive electrode mixture) held on the positive electrode lattice. Since the positive electrode is generally plate-shaped, it is also called a positive electrode plate.

The lead grid material is exemplified by lead or a lead alloy. The lead alloy may include, for example, Ba, Ag, Ca, Al, Bi, Sb, and / or Sn. From the viewpoint of easily obtaining high corrosion resistance and mechanical strength, it is preferable to use a lead alloy containing Ca and / or Sn. In the lead alloy, the Ca content may be 0.01% by mass to 0.10% by mass, and the Sn content may be 0.05% by mass to 3.00% by mass.

Lead oxide (PbO ₂ ) is used as the positive electrode active material. When producing a positive electrode, you may use the lead powder containing lead oxide as a positive electrode active material.
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) in addition to the positive electrode active material. The positive electrode may contain a known additive as required.

The positive electrode can be formed by filling or applying a positive electrode paste (a paste containing a positive electrode active material or a positive electrode mixture paste) to a positive electrode grid, and drying to produce an unformed positive electrode, followed by chemical conversion treatment. The positive electrode paste contains sulfuric acid and / or water as a dispersion medium in addition to the components of the positive electrode active material or the positive electrode mixture. The drying step may be an aging drying step that dries at a temperature and humidity higher than room temperature. The chemical conversion treatment can be performed by charging in a state where the positive electrode and the negative electrode before conversion are immersed in an electrolyte containing sulfuric acid in the battery case of the lead storage battery.

(Negative electrode)
A negative electrode of a lead storage battery generally includes a negative electrode lattice (such as an expanded lattice or a cast lattice) and a negative electrode active material (or a negative electrode mixture) held by the negative electrode lattice. Since the negative electrode is generally plate-shaped, it is also called a negative electrode plate.

As the material of the negative electrode grid, lead or a lead alloy exemplified for the positive electrode grid can be exemplified. Among these, a lead alloy containing Ca and / or Sn is preferable, and a lead alloy containing at least Ca is also preferable from the viewpoint of mechanical strength. In the lead alloy, the Ca content may be 0.01% by mass to 0.10% by mass, and the Sn content may be 0.20% by mass to 0.60% by mass.

Lead is used as the negative electrode active material. In producing the negative electrode, lead powder can be used, and the lead powder may contain lead oxide. The negative electrode mixture may contain a shrinkage-preventing agent (such as lignin and / or barium sulfate), a conductive agent (such as a conductive carbonaceous material such as carbon black), and / or a binder (such as a polymer). Examples of lignin include synthetic lignin such as natural lignin and bisphenol sulfonic acid condensate.
The negative electrode may contain other known additives as necessary.
The negative electrode can be formed according to the case of the positive electrode.

(Separator)
Examples of the separator include a microporous membrane or a fiber sheet (or mat). As a polymer material which comprises a microporous film or a fiber sheet, what has acid resistance is preferable, and polyolefin, such as polyethylene and a polypropylene, can be illustrated. The fiber sheet may be formed of polymer fibers (fibers formed of the polymer material) and / or inorganic fibers such as glass fibers.
The separator may contain an additive such as a filler and / or carbon, if necessary.

(Electrolytes)
The electrolyte is based on a sulfuric acid aqueous solution, and further contains titanium ions and aluminum ions.
The electrolyte can be prepared by adding a titanium ion source (such as a titanium compound) and an aluminum ion source (such as an aluminum compound or aluminum) to an aqueous sulfuric acid solution and dissolving the titanium ions and aluminum ions. As the titanium ion source and the aluminum ion source, those that at least partially dissolve in an aqueous sulfuric acid solution to generate titanium ions and aluminum ions can be used.

Examples of the titanium compound as a titanium ion source include inorganic salts of titanium (sulfates such as dititanium sulfate, sulfites, carbonates, bicarbonates, phosphates, borates, etc.) and titanium. Oxides, titanic acid hydrates (TiO ₂ .xH ₂ O (0 <x <1)), titanic acids (such as metatitanic acid (H ₂ TiO ₃ )), and titanates (such as metatitanates) Can be mentioned. The metatitanic acid salt, typically a metal salt (Li _₂ TiO _3, K ₂ alkali metal salts such as TiO _3; such as _{_{_{PbTiO 3, ZnTiO 3; MgTiO 3}}} , CaTiO 3, SrTiO alkaline earth metal salts such as _3); FeTiO ₃ , transition metal salts such as CoTiO ₃ and MnTiO ₃ can be exemplified. These titanium compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

Of the titanium compounds, the inorganic acid salt of titanium (first titanium compound) is highly soluble in sulfuric acid aqueous solution (or dissociation of titanium ions) and can easily adjust the titanium ion concentration. For this reason, it is preferable to use at least a first titanium compound (particularly, sulfate or the like) as the titanium compound. Further, a titanium compound other than the first titanium compound (oxide containing titanium, titanic acid hydrate, titanic acid, and titanate; hereinafter also referred to as a second titanium compound) may be used.

The lead acid battery may include a solid titanium compound that is placed in contact with the electrolyte. Especially, the 2nd titanium compound has low solubility with respect to sulfuric acid aqueous solution compared with a 1st titanium compound. When such a second titanium compound is disposed in the lead acid battery so as to be in contact with the electrolyte in a solid state, a part of the solid second titanium compound becomes titanium ions and dissolves in the electrolyte. Therefore, when charging and discharging are repeated, titanium ions are continuously replenished into the electrolyte from the solid second titanium compound, and the decrease in titanium ions in the electrolyte can be suppressed. The decrease can also be suppressed. As the second titanium compound, metatitanic acid, titanic acid hydrate and / or titanate are preferable, and among these, metatitanic acid is preferable.

The solid titanium compound (such as the second titanium compound) may be contained in, for example, the positive electrode, the negative electrode, and / or the separator, but is contained in the electrolyte (specifically, immersed in the electrolyte). Preferably). A solid titanium compound may be dispersed in the electrolyte. The form of the solid titanium compound is not particularly limited, but may be powder, granule, pellet, or the like. A first titanium compound and an aluminum ion source (such as an aluminum compound) may be added in advance to a sulfuric acid aqueous solution and dissolved, and then a solid second titanium compound having low solubility may be added.

The amount of the second titanium compound can be adjusted as appropriate so that the concentration of titanium ions in the electrolyte during charging and discharging falls within the above range. When the second titanium compound is immersed in the electrolyte, the amount of the second titanium compound per liter of the electrolyte is, for example, 0.1 mmol to 50 mmol, and preferably 1 mmol to 40 mmol.

Examples of the aluminum compound that is an aluminum ion source include inorganic acid salts and hydroxides exemplified for the titanium compound. Further, aluminum may be used as the aluminum ion source. An aluminum ion source may be used alone or in combination of two or more. From the viewpoint of easily adjusting the aluminum ion concentration, it is preferable to use an inorganic acid salt, particularly a sulfate, among the aluminum ion sources.

The concentration of titanium ions in the electrolyte depends on the amount of titanium compound added, the type of titanium compound, the physical properties of the titanium compound (surface area, particle size, etc.), the form of the titanium compound, and / or the density of the electrolyte (or aqueous sulfuric acid used in the electrolyte) The density can be adjusted. Similarly to the case of titanium ions, the concentration of aluminum ions in the electrolyte can be adjusted by the addition amount, type, physical properties, form, and / or density of the electrolyte (or sulfuric acid aqueous solution). it can.

The density of the electrolyte is, for example, 1.10 g / cm ³ to 1.35 g / cm ³ , and preferably 1.25 g / cm ³ to 1.30 g / cm ³ . When the density of the electrolyte is in such a range, the concentration of titanium ions and aluminum ions in the electrolyte is easily maintained in an appropriate range. In this specification, the density of the electrolyte is a density at 20 ° C. The density of the electrolyte in the fully charged battery is preferably in the above range. Moreover, you may set the density (density in 20 degreeC) of sulfuric acid aqueous solution in the said range described as the density of electrolyte.

A lead-acid battery can be produced by housing an electrode plate group and an electrolyte in a battery case (battery case). 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 are alternately arranged with a separator interposed therebetween. The separator may be disposed so as to be interposed between the positive electrode and the negative electrode, and a bag-shaped separator is used, or a sheet-shaped separator is folded in half (U-shaped), and one electrode is sandwiched between the other. You may overlap with an electrode. A plurality of electrode plate groups may be accommodated in the battery case.

FIG. 1 is a partially cutaway perspective view schematically showing a lead storage battery according to an embodiment of the present invention. 2 is a front view of the positive electrode plate of FIG. 1, and FIG. 3 is a front view of the negative electrode plate of FIG.
The lead storage battery 1 includes an electrode plate group 11 and an electrolyte (not shown), which are accommodated in a battery case 12. More specifically, the battery case 12 is partitioned into a plurality of cell chambers 14 by partition walls 13, and each cell chamber 14 stores one electrode plate group 11 and also stores an electrolyte. The electrode plate group 11 is configured by laminating a plurality of positive electrode plates 2 and negative electrode plates 3 with a separator 4 interposed therebetween.

Ears 22 are provided on the positive electrode grid of the positive electrode plate 2, and the positive electrode plate 2 is connected to the positive electrode connecting member 10 via the ears 22. The positive electrode connection member 10 includes a positive electrode shelf 6 connected to the ears 22 of the positive electrode lattice, and a positive electrode connector 8 or a positive electrode column provided on the positive electrode shelf 6. Similarly, the negative electrode lattice of the negative electrode plate 3 is provided with ears 32, and the negative electrode plate 3 is connected to the negative electrode connection member 9 via the ears 32. The negative electrode connection member 9 includes a negative electrode shelf 5 connected to the ear 32 of the negative electrode lattice, and a negative electrode column 7 or a negative electrode connector provided on the negative electrode shelf 5. In the illustrated example, a positive electrode connector 8 is connected to the positive electrode shelf 6 at one end of the battery case 12, and a negative electrode column 7 is connected to the negative electrode shelf 5. At the other end of the battery case 12, a positive pole is connected to the positive electrode shelf 6, and a negative electrode connector is connected to the negative electrode shelf 5.

In each cell, the entire positive electrode shelf, negative electrode shelf, and electrode plate group are immersed in an 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 connection body 8 is connected to a negative electrode connection body connected to the negative electrode shelf of the electrode plate group 11 in the adjacent cell chamber 14 through a through hole provided in the partition wall 13. Thereby, 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 pole 7 is connected to the negative terminal 17, and at the other end, the positive pole is connected to the positive terminal 16. An exhaust plug 18 having an exhaust port for discharging gas generated inside the battery to the outside of the battery is attached to the liquid injection port provided in the lid 15.

The positive electrode plate 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 grid 21 is an expanded grid composed of an expanded mesh 25 that holds the positive active material layer 24, a frame bone 23 provided at the upper end of the expanded mesh 25, and ears 22 connected to the frame bone 23.

Similarly, the negative electrode plate 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 expanded lattice composed of an expanded mesh 35 that holds the negative electrode active material layer 34, a frame bone 33 provided at the upper end of the expanded mesh 35, and an ear 32 connected to the frame bone 33.

EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example and a comparative example, this invention is not limited to a following example.
Example 1
(1) Production of positive electrode plate A positive electrode plate 2 shown in FIG. 2 was produced by the following procedure.
A raw material powder (mixture of lead and lead oxide), water and dilute sulfuric acid (density 1.40 g / cm ³ ) were mixed at a mass ratio of 100: 15: 5 to obtain a positive electrode paste.

A base material sheet made of a Pb-0.06 mass% Ca-1.6 mass% Sn alloy obtained by a casting method and a lead alloy foil containing Sb were rolled and rolled. Thereby, the lead alloy foil was pressure-bonded on the base material sheet, and a composite sheet having a lead alloy layer containing Sb having a thickness of 20 μm on one surface of the base material layer having a thickness of 1.1 mm was obtained. The lead alloy foil is crimped to the base material sheet only at the part where the expanded mesh is formed in the later-described expanding process, and the center part of the base material sheet where the ears 22 and the frame bone 23 are formed is lead. The alloy foil was not crimped.

After forming a predetermined slit in the composite sheet, this slit was developed to form an expanded mesh 25 to obtain an expanded lattice. In addition, the expanding process was not performed on the portions forming the ears 22 and the frame bones 23 of the positive electrode lattice described later.

The expanded mesh 25 was filled with a positive electrode paste, and cut into an electrode plate shape having positive electrode grid ears 22. This was aged and dried to obtain an unformed positive electrode plate (vertical: 115.0 mm, horizontal: 137.5 mm). And the positive electrode plate 2 by which the positive electrode active material layer 24 was hold | maintained at the positive electrode grid 21 was obtained by forming in a battery case mentioned later.

(2) Production of Negative Electrode Plate A negative electrode plate 3 shown in FIG. 3 was produced by the following procedure.
Raw material lead powder, water, dilute sulfuric acid (density 1.40 g / cm ³ ), lignin and barium sulfate as a shrinkage preventive agent, and carbon black as a conductive material in a mass ratio of 100.0: 12.0: 7.0: 1. A negative electrode paste was obtained by mixing at a ratio of 0: 0.1.

A base material sheet made of a Pb-0.07 mass% Ca-0.25 mass% Sn alloy obtained by a casting method is rolled to a thickness of 0.7 mm, and the base material sheet is expanded by the same method as described above. did. The expanded mesh was filled with a negative electrode paste, and an unformed negative electrode plate (vertical: 115.0 mm, horizontal 137.5 mm) was obtained by the same method as described above. And the negative electrode plate 3 by which the negative electrode active material layer 34 was hold | maintained at the negative electrode lattice 31 was obtained by forming in the battery case mentioned later.

(3) Production of lead acid battery A lead acid battery 1 as shown in FIG. 1 was produced according to the following procedure.
By laminating the single negative electrode plate 3 obtained above with the separator 4 (1.0 mm thick glass fiber mat) sandwiched between the two positive electrode plates 2, the electrode plate group 11 is formed. Obtained. At this time, the separator 4 was folded in two and disposed so as to sandwich the negative electrode plate therebetween.

Next, the

ears

22 and 32 were collectively welded to form the positive electrode shelf 6 and the negative electrode shelf 5. The electrode plate group 11 was housed one by one in each of the six cell chambers 14 partitioned by the partition wall 13 of the battery case 12. By connecting the positive electrode connector 8 connected to the positive electrode shelf 6 to the negative electrode connector connected to the negative electrode shelf of the adjacent electrode plate group, the adjacent electrode plate groups were connected in series. In this example, the connection between the electrode plate groups was made through a through hole (not shown) provided in the partition wall 13. A Pb-2.5 mass% Sn alloy was used for the positive electrode connector and the negative electrode connector.

A positive electrode column was provided on one positive electrode shelf of the electrode plate group housed in the cell chambers 14 at both ends, and a negative electrode column 7 was provided on the other negative electrode shelf 5. The lid 15 was attached to the opening of the battery case 12, and the positive electrode terminal 16 and the negative electrode terminal 17 provided on the lid 15 were welded to the positive electrode column and the negative electrode column 7. Thereafter, a predetermined amount of electrolyte was injected from the injection port provided in the lid 15 and chemical conversion was performed in the battery case. After the formation, an exhaust plug 18 having an exhaust port for discharging the gas generated inside the battery to the outside of the battery was attached to the injection port, and a 55D23 type (12V-48Ah) lead storage battery defined in JIS D5301 was produced. . In addition, after the chemical conversion, the entire electrode plate group 11, the positive electrode shelf 6, and the negative electrode shelf 5 were immersed in the electrolyte.

As the electrolyte, a solution in which titanium sulfate and aluminum sulfate were dissolved in sulfuric acid (aqueous sulfuric acid solution, density 1.28 g / cm ³ ) was used. Titanium sulfate and aluminum sulfate were used in such amounts that the concentration of titanium ions in the electrolyte was 0.95 mmol / L and the concentration of aluminum ions was 9.5 mmol / L, respectively.

(4) Evaluation A test cell was prepared by the following procedure (a). The following (b) and (c) were evaluated using the produced test cell. Note that 1.0 C of the test cell was calculated from the theoretical capacity of each test cell.

(A) Production of test cell The positive electrode plate and the negative electrode plate produced in the above (1) and (2) were cut into a size of 60 mm in length and 40 mm in width, respectively, and one negative electrode plate and two positive electrode plates were obtained. Got ready. The negative electrode plate group was formed by laminating the negative electrode plate through a separator (polyethylene microporous film, thickness 0.2 mm, width 44 mm) sandwiched between two positive electrode plates. At this time, the separator 4 was disposed so as to sandwich the negative electrode plate while being folded in half.

The obtained electrode plate group was sandwiched between acrylic plates from both sides and fixed. Next, a lead bar was welded to each of the negative electrode plate and the two positive electrode plates to form a negative electrode terminal and a positive electrode terminal, respectively. It was placed in a polypropylene container, and a predetermined amount of sulfuric acid having a density of 1.20 g / cm ³ was injected to perform chemical conversion. The sulfuric acid in the cell used for chemical conversion was removed, and sulfuric acid having a predetermined composition described below was newly injected. In this way, a test cell (1.25 Ah, 2 V) was produced. As the electrolyte, the same one as used in (3) was used.

(B) Charge acceptance (initial charge acceptance)
Under the following conditions, the SOC of the test cell after conversion was adjusted and charged. The 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 Rest: 12 hours Charge (Charge acceptance): Constant current (3C)-Constant voltage (2.4V, maximum current 3C), 60 seconds Temperature: 25 ° C

(C) Utilization rate of negative electrode active material About the test cell after chemical conversion, constant current discharge was carried out at 0.2 C to the final voltage 1.7V, and the cell capacity at this time was measured. Based on this cell capacity, the negative electrode active material capacity (mAh / g) was determined. The negative electrode active material utilization rate was expressed as a ratio (%) of the negative electrode active material capacity (mAh / g) to the cell theoretical capacity, with 50% of the negative electrode active material of each cell being the theoretical capacity of the cell.

Examples 2 to 7 and Comparative Examples 1 to 14
A test cell was prepared and evaluated in the same manner as in Example 1 except that the amount of titanium sulfate and / or aluminum sulfate was changed so that the concentration of titanium ions in the electrolyte was the value shown in Table 1. .

Table 1 shows the results of Examples 1 to 7 and Comparative Examples 1 to 14. In addition, about charge acceptance, it represented with the ratio (charge acceptance ratio) when the initial stage electric current value of the comparative example 1 was set to 100%. About the negative electrode active material utilization factor, it represented with the ratio (negative electrode utilization factor ratio) when the negative electrode active material capacity | capacitance of the comparative example 1 was set to 100%. Examples 1 to 7 were designated as A1 to A7, and Comparative Examples 1 to 14 were designated as B1 to B14.

As shown in Table 1, in an example in which the concentration of titanium ions in the electrolyte is less than 1 mmol / L and the concentration of aluminum ions is less than 10 mmol / L, charging is performed while ensuring a high negative electrode utilization rate. The decline in acceptability is suppressed. In these examples, the charge acceptance is improved as compared with B1 to B5, B8 and B9 of comparative examples not containing titanium ions and / or aluminum ions.

In comparative examples B6, B7, and B10 to B14 in which the concentration of titanium ions or the concentration of aluminum ions is higher than that of the example, the charge acceptance is the same as or better than that of the example. However, even if the charge acceptance is improved, the degree of improvement in charge acceptance is not commensurate with the increase in concentration. Moreover, in these comparative examples, the negative electrode utilization factor is lower than that of the examples.

Example 8
An electrolyte was prepared by dissolving aluminum sulfate in sulfuric acid (aqueous sulfuric acid solution, density 1.28 g / cm ³ ), adding metatitanic acid powder (manufactured by Kishida Chemical Co., Ltd.), and stirring. Aluminum sulfate was used in such an amount that the concentration of aluminum ions in the electrolyte was 9.5 mmol / L, and the amount of metatitanic acid per liter of the electrolyte was 40 mmol. The electrolyte was in a state containing solid metatitanic acid. A test cell was prepared and evaluated in the same manner as in Example 1 except that the electrolyte thus obtained was used.

Example 8 was further evaluated as follows.
(Titanium ion concentration in the electrolyte)
The concentration of titanium ions in the electrolyte was quantified by the following procedure. First, the test cell was charged and discharged at 20 ° C. with a constant current of 0.2 C for 7.5 hours and then discharged to 1.7 V with a constant current of 0.2 C. Further, after charging for 7.5 hours at a constant current of 0.2 C, a predetermined amount of electrolyte was collected from the test cell, the solid titanium compound was removed by centrifugation, and the supernatant was filtered through a filter (pore size: 0.1 μm). . The filtrate was collected and diluted, and the amount of titanium was quantified by ICP emission spectroscopy to determine the titanium ion concentration of the electrolyte.

(Charge acceptance after 360 cycles)
First, the SOC of the formed test cell was adjusted under the following conditions.
Charging (SOC adjustment): constant current, 0.2C, 7.5 hours Pause: 30 minutes Discharge (SOC adjustment): constant current, 0.2C, 30 minutes Pause: 12 hours Temperature: 25 ° C

Next, based on the idling stop (IS) life test (SBA S0101), charge and discharge under the following conditions where the deterioration of the negative electrode is easy to accelerate were repeated 360 cycles.
Charge (IS): constant current (2.25C) -constant voltage (2.4V, maximum current 2.25C), 0.1 hour Discharge (IS): constant current, 1.0C, 0.1 hour Temperature: 25 ℃
And the charge acceptance property after 360 cycles was evaluated on condition of the following.
Charging (charge acceptance): constant current (3C)-constant voltage (2.4V, maximum current 3C), 60 seconds Temperature: 25 ° C

Example 9
An electrolyte was prepared in the same manner as in Example 8 except that the amount of aluminum sulfate used was changed so that the concentration of aluminum ions in the electrolyte was 5.0 mmol / L. The electrolyte was in a state containing solid metatitanic acid. A test cell was prepared and evaluated in the same manner as in Example 1 except that the obtained electrolyte was used. The same evaluation as in Example 8 was also performed.

The results of Examples 8 to 9 are shown in Table 2. The charge acceptability was expressed as a ratio (charge acceptability ratio) when the initial current value of Comparative Example 1 was 100%. About the negative electrode active material utilization factor, it represented with the ratio (negative electrode utilization factor ratio) when the negative electrode active material capacity | capacitance of the comparative example 1 was set to 100%. Examples 8 to 9 are represented by A8 to A9. Table 2 also shows the results of the same evaluation as in Example 8 for Examples 4 and 5.

As shown in Table 2, in Examples A8 and A9, the initial charge acceptance was as high as A4 and A5, but the charge acceptance after 360 cycles was higher than that of A4 and A5. It was. In A8 and A9, the utilization rate of the negative electrode was high as in Examples A4 and A5.

The lead storage battery according to one embodiment of the present invention has high charge acceptability, and a decrease in the utilization factor of the negative electrode is suppressed. Therefore, it is easy to obtain an effect even in a use mode in which charging / discharging is repeated in the mid-charging state, and is particularly suitable for use in a vehicle equipped with an idle stop system or a regenerative braking system.

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

Claims

A lead-acid battery comprising a positive electrode, a negative electrode, a separator interposed between the positive electrode and the negative electrode, and an electrolyte containing sulfuric acid,
The electrolyte further includes titanium ions and aluminum ions,
The concentration of the titanium ions in the electrolyte is less than 1.00 mmol / L;
The lead acid battery, wherein the concentration of the aluminum ions in the electrolyte is less than 10.0 mmol / L.
The concentration of the titanium ions in the electrolyte is 0.08 mmol / L to 0.97 mmol / L,
The lead acid battery according to claim 1, wherein the concentration of the aluminum ions in the electrolyte is 0.8 mmol / L to 9.7 mmol / L.
The concentration of the titanium ions in the electrolyte is 0.10 mmol / L to 0.95 mmol / L,
The lead acid battery according to claim 1 or 2, wherein the concentration of the aluminum ions in the electrolyte is 1.0 mmol / L to 9.5 mmol / L.
The lead acid battery according to any one of claims 1 to 3, wherein the lead acid battery includes a solid titanium compound disposed so as to be in contact with the electrolyte.
The lead storage battery according to claim 4, wherein the titanium compound is immersed in the electrolyte.
The lead acid battery according to claim 4 or 5, wherein the titanium compound is at least one selected from the group consisting of metatitanic acid, titanic acid hydrate, and metatitanate.