Lead-acid battery

Abstract

A lead-acid battery includes a separator retaining an electrolyte solution, a positive electrode plate, a negative electrode plate, and a container. A negative electrode material contains bisphenols condensate, and a theoretical capacity ratio of the negative electrode material to a positive electrode material is 0.85 or more and 1.2 or less.

Claims

1. A lead-acid battery comprising a separator retaining an electrolyte solution, a positive electrode plate, a negative electrode plate, and a container, wherein a negative electrode material of the negative electrode plate contains bisphenols condensate, a theoretical capacity ratio B/A of a theoretical capacity B of the negative electrode material to a theoretical capacity A of a positive electrode material of the positive electrode plate is 0.85 or more and 1.2 or less, the separator is a nonwoven fabric-like or mat-like separator made of glass fibers or synthetic resin fibers, and a median pore size of the nonwoven fabric-like or mat-like separator is 3 m or more and 8 m or less in a state in which a compression force of 30 to 50 kg/dm.sup.2 is applied to the nonwoven fabric-like or mat-like separator retaining the electrolyte solution in the container.

2. The lead-acid battery according to claim 1, wherein the negative electrode material further contains carbon black.

3. The lead-acid battery according to claim 2, wherein the negative electrode material contains the carbon black in an amount of 0.1% by mass or more and 1.5% by mass or less.

4. The lead-acid battery according to claim 1, wherein the lead-acid battery is a retainer type lead-acid battery.

5. The lead-acid battery according to claim 1, wherein the negative electrode material contains the bisphenols condensate in an amount of 0.05% by mass or more and 0.25% by mass or less.

6. The lead-acid battery according to claim 1, wherein the bisphenols condensate is bisphenols formaldehyde condensate.

7. The lead-acid battery according to claim 1, wherein the negative electrode plate retains 15% by mass or more of a total amount of the electrolyte solution.

8. The lead-acid battery according to claim 1, wherein the negative electrode plate retains 15% by mass or more and 25% by mass or less of a total amount of the electrolyte solution.

9. The lead-acid battery according to claim 1, wherein the theoretical capacity ratio B/A is 0.9 or more and 1.2 or less.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) FIG. 1 is a side view of a main part of a retainer type lead-acid battery of Examples.

MODE FOR CARRYING OUT THE INVENTION

(2) Hereinafter, an optimum example of the present invention will be described. In embodying the present invention, the example can be appropriately modified according to common sense of those skilled in the art and disclosure of the prior art.

Examples

(3) A negative electrode material containing a lead powder, bisphenols condensate (formaldehyde condensate of bisphenol A having a sulfone group introduced therein), carbon black, barium sulfate and synthetic resin fibers was formed into a paste with sulfuric acid, and the resulting paste was filled into a negative current collector made of a PbCaSn-based expanded grid, dried and cured to form an unformed negative electrode plate. Similarly, a positive electrode material containing a lead powder and synthetic resin fibers was formed into a paste with sulfuric acid, and the resulting paste was filled into a positive current collector made of a PbCaSn-based expanded grid, dried and cured to form an unformed positive electrode plate. Further, a total thickness of the positive electrode plate and the negative electrode plate was kept constant, and the theoretical capacity ratio of the negative electrode material to the positive electrode material was varied in a range of 0.8 to 1.25 by adjusting the amounts of the positive active material and the negative active material so as to be an intended theoretical capacity ratio.

(4) Four kinds of mat-like separators, whose medians of the pore size distribution were 1 m or more and less than 3 m, 3 m or more and less than 5 m, 5 m or more and less than 8 m, and 8 m or more in a state in which compression was applied, were prepared. The pore size was adjusted by varying a density of the glass fiber or the synthetic resin fiber to be used for a separator.

(5) Using four negative electrode plates and five positive electrode plates, the mat-like separator was sandwiched between the plates and housed in a container in a state in which compression was applied, and sulfuric acid having a specific gravity of 1.25 was added to perform formation in container to produce a retainer type lead-acid battery. A structure of the retainer type lead-acid battery is schematically shown in FIG. 1, and a reference numeral 2 indicates a negative electrode plate, 4 indicates a positive electrode plate, and 6 indicates a separator.

(6) Retainer type lead-acid batteries (theoretical capacity ratio: 1.0 and 0.85) of comparative examples were produced in the same manner as in examples described above except for preparing a negative active material paste which contains lignin in place of bisphenols condensate, contains carbon black, barium sulfate and synthetic resin fibers, and is predominantly composed of a lead powder.

(7) On three of each type of the lead-acid battery, a life cycle test composed of a cycle of 4 minutes discharge at 1 CA and 10 minutes charge at a constant voltage of 2.47 V (maximum current 1 CA) was performed according to JIS D 5302, and the number of life cycles was measured using one of tested storage batteries. Another one storage battery was fully charged after a lapse of 7200 cycles, and disassembled, and a ratio in which the lead in the negative active material was changed to lead sulfate and the amount of the electrolyte solution decrease were measured. In addition, if a life cycle was shorter than 7200 cycles, measurement was performed at the time of the life. Moreover, remaining one storage battery was fully charged and disassembled before a life test, and based on the masses of the positive electrode plate, the negative electrode plate and the mat-like separator measured before water washing and drying and the masses of the positive electrode, the negative electrode plate and the mat-like separator measured after water washing and drying, rates of the electrolyte solutions retained in them were determined.

(8) These measurement results are shown in Table 1 to Table 9. The accumulation amount of lead sulfate could be reduced significantly by using the bisphenols condensate in place of lignin. Then, when the theoretical capacity ratio of the negative electrode material to the positive electrode material was 0.85 or more and 1.2 or less, preferably 0.9 or more and 1.2 or less, the accumulation of lead sulfate could be suppressed and the amount of the electrolyte solution decrease could be reduced. Moreover, when the median pore size of the mat-like separator was 3 m or more and 8 m or less, a rate at which the negative electrode plate retains the electrolyte solution can be increased, and the number of life cycles was remarkably increased. Further, when the negative electrode plate retains 15% by mass or more of the total amount of an electrolyte solution, the number of life cycles increased remarkably. By using bisphenols condensate, adjusting the theoretical capacity ratio of the negative electrode material to the positive electrode material appropriately, and adjusting the median pore size of the mat-like separator to 3 m or more and 8 m or less, a retainer type lead-acid battery was obtained in which accumulation of the lead sulfate was low, an amount of the electrolyte solution decrease was small, and the number of cycles repeated until reaching a life was large.

(9) TABLE-US-00001 TABLE 1 Expander, carbon Lignin 0.2% + Lignin 0.2% + Bisphenols 0.2% + Carbon 0.3% Carbon 1.0% Carbon 0.3% Separator Pore Size at the 1-3 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 0.85 1.00 Lead Sulfate Amount in 35 28 25 25 24 24 28 37* 35* Negative Electrode/% Amount of Electrolyte 24 22 20 20 21 23 30 35* 32* Solution Decrease/% Distribution of Positive 30 28 26 Electrolyte Electrode Solution Separator 60 60 60 Amount Negative 10 12 14 Electrode Number of Life Cycles 5760 6240 7200 8160 7680 7200 5760 4800 5760 *If a life cycle is shorter than 7200 cycles, a value at the time of the life is shown.

(10) TABLE-US-00002 TABLE 2 Expander, carbon Lignin 0.2% + Lignin 0.2% + Bisphenols 0.2% + Carbon 0.3% Carbon 1.0% Carbon 0.3% Separator Pore Size at the 3-5 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 0.85 1.00 Lead Sulfate Amount in 23 19 16 15 15 16 20 38* 35* Negative Electrode/% Amount of Electrolyte 18 16 16 15 16 16 18 34* 35* Solution Decrease/% Distribution of Positive 40 38 36 Electrolyte Electrode Solution Separator 45 45 45 Amount Negative 15 17 19 Electrode Number of Life Cycles 10560 12480 13920 14400 14400 13920 12480 5280 6240

(11) TABLE-US-00003 TABLE 3 Expander, carbon Lignin 0.2% + Lignin 0.2% + Bisphenols 0.2% + Carbon 0.3% Carbon 1.0% Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 0.85 1.00 Lead Sulfate Amount in 36 30 23 20 21 22 28 37* 38* Negative Electrode/% Amount of Electrolyte 23 21 19 18 18 23 25 36* 37* Solution Decrease/% Distribution of Positive 42 40 38 Electrolyte Electrode Solution Separator 40 40 40 Amount Negative 18 20 22 Electrode Number of Life Cycles 10080 12000 13440 13920 13920 13440 12000 5280 6240

(12) TABLE-US-00004 TABLE 4 Expander, carbon Lignin 0.2% + Lignin 0.2% + Bisphenols 0.2% + Carbon 0.3% Carbon 1.0% Carbon 0.3% Separator Pore Size at the 8-12 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 0.85 0.85 Lead Sulfate Amount in 40 35 26 24 25 28 30 38* 36* Negative Electrode/% Amount of Electrolyte 28 26 23 21 22 28 32 34* 34* Solution Decrease/% Distribution of Positive 50 49 48 Electrolyte Electrode Solution Separator 38 38 38 Amount Negative 12 13 14 Electrode Number of Life Cycles 5760 8640 10560 11040 10080 9120 6240 4800 4800

(13) While the content of the bisphenols condensate was 0.2% by mass in Table 1 to Table 4, the content was optional. The results shown in Table 5 to Table 11 were obtained in the same manner as in the above-mentioned Example except for varying the content of the bisphenols condensate. From these Tables, it is found that the content of the bisphenols condensate in the negative electrode material is preferably 0.05% by mass or more and 0.25% by mass or less.

(14) TABLE-US-00005 TABLE 5 Expander, carbon Bisphenols 0.03% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 40 34 28 24 25 27 33 Negative Electrode/% Amount of Electrolyte 22 20 18 17 18 21 24 Solution Decrease/% Number of Life Cycles 5760 7680 8160 9120 8640 7680 7200

(15) TABLE-US-00006 TABLE 6 Expander, carbon Bisphenols 0.05% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 36 30 23 20 21 22 28 Negative Electrode/% Amount of Electrolyte 27 25 23 22 22 26 30 Solution Decrease/% Number of Life Cycles 7200 8640 9120 10560 10080 9120 8640

(16) TABLE-US-00007 TABLE 7 Expander, carbon Bisphenols 0.1% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 37 32 24 21 22 24 29 Negative Electrode/% Amount of Electrolyte 23 21 18 18 17 23 25 Solution Decrease/% Number of Life Cycles 8640 10080 10560 11040 10080 10080 9120

(17) TABLE-US-00008 TABLE 8 Expander, carbon Bisphenols 0.2% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 36 30 23 20 21 22 28 Negative Electrode/% Amount of Electrolyte 23 21 19 18 18 23 25 Solution Decrease/% Number of Life Cycles 10080 12000 13440 13920 13920 13440 12000

(18) TABLE-US-00009 TABLE 9 Expander, carbon Bisphenols 0.25% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 35 29 23 19 20 22 27 Negative Electrode/% Amount of Electrolyte 24 22 20 19 20 25 27 Solution Decrease/% Number of Life Cycles 10080 12480 13440 14400 14400 13440 12480

(19) TABLE-US-00010 TABLE 10 Expander, carbon Bisphenols 0.30% + Carbon 0.3% Separator Pore Size at the 5-8 m Time of Compression /+Theoretical Capacity Ratio 0.80 0.85 0.90 1.00 1.10 1.20 1.25 Lead Sulfate Amount in 36 30 23 20 21 22 28 Negative Electrode/% Amount of Electrolyte 27 25 23 22 22 26 30 Solution Decrease/% Number of Life Cycles 7200 7680 8160 9120 8640 8640 7680

(20) The content of the carbon black in the negative electrode material is preferably 0.1% by mass or more and 1.5% by mass or less, and a kind of the carbon black is optional. The positive electrode material and the negative electrode material may contain additives other than the compounds of the lead-acid batteries shown in Tables 1-10, and may not contain barium sulfate and synthetic resin fibers. Moreover, composition, a structure and the like of the current collector are optional, and a kind of lead powder and conditions of formation are optional.

DESCRIPTION OF REFERENCE SIGNS

(21) 2 Negative electrode plate 4 Positive electrode plate 6 Mat-like separator