JP6520249B2 - Method of manufacturing lead storage battery - Google Patents

Description

  The present invention relates to a lead-acid battery for starting an automobile.

  The positive electrode plate and the negative electrode plate, which are the power generation elements of the lead storage battery, are each composed of a positive electrode grid and a positive electrode active material, and a negative electrode grid and a negative electrode active material. As a practical means of manufacturing the positive electrode grid and the negative electrode grid, in addition to a casting method (including a continuous casting method) in which a molten alloy of lead alloy is cast, the lead alloy sheet is cut and then spread in the width direction of the sheet. Finally, there is an expanding method (including both the reciprocation method and the rotary method) of cutting into the shape of the electrode plate.

  On the other hand, in order to enhance the productivity of the positive electrode grid and the negative electrode grid, practical application of a punching method in which holes are formed in a lead alloy sheet and finally cut into the shape of an electrode plate is being attempted. In Patent Document 1, as an effective method for any of a casting method, an expanding method and a punching method, a lead alloy containing an appropriate amount of bismuth together with other elements is used as a starting material of a positive electrode grid for the purpose of increasing strength. It is shown. Patent Document 1 also shows that calcium contained in a lead alloy used as a starting material of the positive electrode grid should be 100 ppm or less in order to suppress corrosion.

Japanese Patent Publication No. 2010-522275

  Even when an element such as bismuth is added as in Patent Document 1, the lead alloy is relatively soft. Therefore, when the punching method is introduced without sufficiently examining the composition of the lead alloy, when drilling a hole in the lead alloy sheet, the sink marks due to the upper and lower sides of the punching blade (the shape of the portion of the sheet contacting the blade rises in the vertical direction) Will occur. This sinkage not only affects productivity by preventing smooth punching, but when a lead-acid battery is configured using a positive grid or negative grid with excess sinks, the separator separating the two is broken and internal short circuit occurs. It can also cause

  The present invention has been made in view of the above problems, and an object of the present invention is to construct and provide a highly reliable lead-acid battery using a positive electrode grid or a negative electrode grid according to a punching method with high productivity.

The method for producing a lead storage battery according to the present invention comprises laminating a positive electrode plate comprising a positive electrode grid and a positive electrode active material, a negative electrode plate comprising a negative electrode grid and a negative electrode active material, a positive electrode plate and a negative electrode plate via a separator. A manufacturing method of a lead storage battery comprising: an electrode plate group; a battery case having a plurality of cell chambers for storing the electrode plate group and an electrolytic solution; and a lid for sealing the opening of the battery case , At least one of the lattice or the negative electrode lattice is manufactured by a punching method in which a lead alloy sheet containing 1 ppm to 300 ppm bismuth and 700 ppm to 1000 ppm calcium is punched.

In a preferred embodiment, the negative electrode grid is manufactured by a punching method in which a lead alloy sheet containing 1 ppm to 300 ppm bismuth and 700 ppm to 1000 ppm calcium is punched.

  In a preferred embodiment, the electrolyte contains 0.02 mol / L or more and 0.2 mol / L or less of aluminum ions.

  In one preferred embodiment, the bag-like separator contains a negative electrode plate.

  According to the present invention, a highly reliable lead-acid battery can be configured and provided using a positive electrode grid or a negative electrode grid according to a punching method with high productivity.

An outline view schematically showing the lead storage battery of the present invention The figure which showed an example of the principal part of the lead storage battery of this invention

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

  FIG. 1 is an outline view schematically showing a lead storage battery of the present invention, and FIG. 2 is a view showing an example of a negative electrode plate which is a main part of the lead storage battery of the present invention. The plurality of electrode plate groups 4 in which the positive electrode plate 1 and the negative electrode plate 2 are stacked via the separator 3 are housed in a battery case 5 having a plurality of cell chambers 5 a together with an electrolytic solution (not shown). The opening is sealed by the lid 6. The positive electrode plate 1 is made of a positive electrode grid 1a and a positive electrode active material 1b, and the negative electrode plate 2 is made of a negative electrode grid 2a and a negative electrode active material 2b.

  The features of the present invention are twofold. First, at least one of the positive electrode grid 1a and the negative electrode grid 2a is manufactured by a punching method in which a hole is formed in a lead alloy sheet (in this embodiment, as shown in FIG. 2, the negative electrode grid 2a is a punching method) Were produced by Second, the lead alloy sheet contains 1 ppm to 300 ppm bismuth and 400 ppm to 1000 ppm calcium.

  When a grid is manufactured by punching method, a punched blade is moved up and down to make a hole in a lead alloy sheet having a predetermined composition, as shown in FIG. It is possible to obtain a grid such as a casting system that is surrounded by a rigid frame and four rounds while having a production rate such as an expanding system. However, if the punching method is introduced without sufficiently examining the composition of the relatively soft lead alloy, when drilling a hole in the lead alloy sheet, the upper and lower portions of the punching blade may cause sink marks. As a result of intensive investigations by the inventors, it was found that this problem is solved by containing calcium in the range of 400 ppm to 1000 ppm in the lead alloy sheet.

  By containing calcium in an amount of 400 ppm or more, the lead alloy sheet can be given adequate rigidity, so that it becomes difficult to cause sink marks when drilling holes. However, when the content of calcium exceeds 1000 ppm, part of calcium forms an intermetallic compound with bismuth. This is not preferable because the special effects of bismuth described below will not be exhibited.

  The determination of the proper content of bismuth will be described in detail below together with the reason for utilizing the present invention for the negative electrode grid 2a preferentially.

  In recent years, an increasing number of vehicles are performing both idling stop control (ISS) and charge control whose SOC is less than 100%. In a lead storage battery mounted in such a car, while charge and discharge are repeated under an environment where the SOC is less than 100%, the concentration of sulfate ions in the electrolyte of the upper layer is higher than the concentration of sulfate ions in the electrolyte of the lower layer. A phenomenon called "stratification" occurs, which is lowered. As a result, the upper layer relatively depleted in the concentration of sulfate ions is less likely to produce lead sulfate as a discharge product (discharge becomes difficult), while the lower region relatively enriched in concentration of sulfate ions is sulfuric acid Unbalance occurs, which makes it difficult to separate sulfate ions from lead (does not allow charging), and excess lead sulfate in the lower layer precipitates, resulting in overall slowing of the discharge reaction, resulting in cycle life characteristics. Decreases. This stratification is eliminated by agitating the electrolyte that is generated during hydrolysis (gas generation) of the electrolyte that occurs at the end of charge. However, in an environment where the SOC is intentionally controlled to be less than 100%, the end of charging can not be reached, so the above-described effects can not be expected.

  Here, the presence of an appropriate amount of bismuth in the negative electrode grid 2a lowers the hydrogen overvoltage, and hydrogen gas is easily generated even if the SOC is less than 100%, and the diffusion of the electrolytic solution tends to occur, resulting in Stratification will be eliminated. In order to obtain this effect, it is necessary to add 1 ppm or more of bismuth to the negative electrode grid 2a, but if it is included more than 300 ppm, the hydrogen overvoltage drops too much and hydrolysis of the electrolytic solution occurs excessively, resulting in electrolytic solution The rapid decrease accelerates the corrosion of the current collectors (ears) of the positive electrode plate 1 and the negative electrode plate 2 exposed from the electrolytic solution. Further, as the amount of overcharged electricity increases, the corrosion of the positive electrode grid 1a is also accelerated. As a result, the cycle life characteristics are rather reduced.

  In addition, when using this invention for the lead storage battery mounted in the motor vehicle which performs both charge control with less than 100% of ISS and SOC, it is more preferable to use at least one of the following two structures together.

  Lead storage batteries installed in vehicles that perform ISS are required to have higher chargeability (recovery of SOC in a short time) than conventional lead storage batteries. In such a case, by containing aluminum in an amount of 0.02 mol / L or more in the electrolytic solution, high charge acceptance can be realized. On the other hand, since the charge acceptance becomes insufficient even if the content of aluminum is excessive, the upper limit of the content of aluminum is preferably 0.2 mol / L.

  By including the negative electrode plate 2 in the bag-like separator 3, the cycle life characteristics can be further enhanced. If hydrogen gas is easily generated by containing an appropriate amount of bismuth in the negative electrode grid 2a, the electrolytic solution is easily diffused, but it also promotes the separation of the negative electrode active material 2b from the negative electrode plate 2. The problem that the negative electrode active material 2b is dropped from the negative electrode plate 2 occurs when the layer of the negative electrode active material 2b continues to drop gradually from the lowermost portion of the negative electrode plate 2. Therefore, the inventors who have found that the trigger of this problem is the failure mode that "the negative electrode active material 2b drops out from the lowermost part of the negative electrode plate 2 first", as a result of intensive studies, found that the negative electrode plate 2 has a bag shape. By placing the lower part of the negative electrode plate 2 on the bound lower side of the bag-like separator 3 by enclosing it in the separator 3, the trigger of the above-mentioned failure is eliminated and the cycle life characteristic is further enhanced. .

  Hereinafter, the effects of the present invention will be described using examples.

(1) Preparation of Lead Acid Battery The lead acid battery produced in this example is a lead acid battery of D26 L type size defined in JIS D5301. In each cell chamber 5a, seven positive electrode plates 1 and eight negative electrode plates 2 are accommodated, and the negative electrode plate 2 is accommodated in a bag-like separator 3 made of polyethylene.

  The positive electrode plate 1 is prepared by mixing lead oxide powder with sulfuric acid and purified water and filling the paste, which is a precursor of the positive electrode active material 1b, into a positive electrode grid 1a (expanded grid) formed of a lead alloy sheet containing calcium. Made.

  The negative electrode plate 2 shows a paste, which is a precursor of the negative electrode active material 2b prepared by adding carbon and an organic additive to lead oxide powder and kneading with sulfuric acid and purified water, as shown in Table 1 It manufactured filling the negative electrode grid 2a of the punching system which pierced the hole with the punching blade in the lead alloy sheet which has a composition.

  After ripening and drying the produced positive electrode plate 1 and negative electrode plate 2, the negative electrode plate 2 is accommodated in a polyethylene bag-like separator 3 (a part is sandwiched by the plate-like separator 3), and alternately stacked with the positive electrode plate 1 An electrode plate group 4 was produced in which seven positive electrode plates 1 and eight negative electrode plates 2 were stacked via a separator 3. The electrode plate group 4 was respectively accommodated in the cell chamber 5a divided into six, and the six cells were directly connected, and then the opening of the battery case 5 was sealed by the lid 6.

Further, an electrolytic solution consisting of dilute sulfuric acid having a density of 1.28 g / cm ³ was added to form a lead, and a lead storage battery was obtained. At this time, the amount of aluminum ions contained in the electrolytic solution after formation was appropriately adjusted to be the value of (Table 1).

(2) Lifetime characteristics The SOC of the produced lead-acid battery was 90%, and the evaluation was made according to the following procedure.
A. B. discharge for 45 seconds at 45A. Discharge for 1 second at 300 A C.I. 14.0 V constant voltage charge for 60 seconds under limiting current 100 A conditions D. After repeating the charge / discharge cycle of performing A, B, and C in order of 3600 times, as a refresh charge for 30 minutes, 14.0 V constant voltage charge with a limiting current of 50 A E. After leaving for 48 hours, adjust SOC to 90% again. While repeating the procedures of A to E described above, it is judged that the life has been reached when the discharge voltage falls below 7.2 V, and in accordance with this judgment, 3600 It was decided whether to continue the test every cycle. The number of cycles for which test continuation was abandoned is described in Table 1 together with the construction conditions.

(3) Processability of punching type negative electrode grid 2a When producing 100 negative electrode grids 2a by punching method, the condition that the vertical movement of the punching blade stopped even by 1 degree due to the occurrence of sink marks is "x" for short circuit "△" is the condition under which visual observation was not made although clear sink marks (0.2 times to 0.4 times the thickness of the negative electrode grid 2a) could be observed visually, but there is no problem in visual observation, but The conditions under which the thickness of 2a was confirmed to be 0.05 times or more and less than 0.2 times) were identified as “○”, and the conditions not corresponding to any of these were described as “◎” in (Table 1).

(4) Charge Acceptability The charge acceptability test described in JIS D5301 was carried out for each of the batteries of the invention example and the comparative example. Specifically, after performing discharge at a constant current for 5 hours in a 25 ° C. atmosphere for 2.5 hours, leaving at rest for 12 hours or more in a 0 ° C. atmosphere, 14.4 V constant voltage at a 0 ° C. atmosphere Charging (maximum current 100 A) was performed for 10 minutes. The 10-minute current value at this time is also described in Table 1 as an indicator of chargeability.

  The batteries A-1 to A-7 are compared. In the battery A-1 in which calcium contained in the negative electrode grid 2a is less than 400 ppm, the processability by the punching method is significantly reduced. On the other hand, in the battery A-7 in which calcium contained in the negative electrode grid 2a exceeds 1000 ppm, the cycle life characteristics are deteriorated. When the battery A-7 was disassembled, it was confirmed that the stratification of the electrolytic solution was remarkable. Further, analysis of the negative electrode grid 2a of the battery A-7 showed that lead and bismuth hardly coexisted, and instead, an intermetallic compound consisting of calcium and bismuth was confirmed. From this, it can be estimated that bismuth was substantially spent on the formation of the intermetallic compound with calcium, so that the original effect could not be exhibited. Therefore, it is understood that the appropriate range of calcium contained in the negative electrode grid 2a is 400 ppm or more and 1000 ppm or less.

  The batteries B-1 to B-9 are compared. Both the battery B-1 in which the amount of bismuth in the negative electrode grid 2a is less than 1 ppm and the battery B-9 in which the amount of bismuth exceeds 300 ppm have degraded cycle life characteristics. When the respective batteries were disassembled, it was confirmed that the stratification of the electrolyte was remarkable in the battery B-1 and the electrolyte decreased extremely in the battery B-9. Therefore, it is understood that the appropriate range of bismuth contained in the negative electrode grid 2a is 1 ppm or more and 300 ppm or less.

  Considering the evaluation results of the batteries A-1 to A-8 and the evaluation results of the batteries B-1 to B-9 together, both the amount of bismuth and the amount of calcium to be contained in the negative electrode grid 2a should be in appropriate ranges I understand.

  The batteries C-1 to C-7 are compared. Both the battery C-1 in which the aluminum ion in the electrolytic solution is less than 0.02 mol / L and the battery C-7 in which the aluminum ion exceeds 0.2 mol / L have a slight decrease in chargeability. Therefore, it is understood that the aluminum ion contained in the electrolytic solution is preferably 0.02 mol / L or more and 0.2 mol / L or less.

  Battery D and battery A-4 are compared. Battery D is configured in the same manner as battery A-4 except that the lower side of the polyethylene separator 3 is not bound to the battery A-4 but is formed into two flat plates, but the cycle life characteristic is It is slightly decreasing. When the battery D was disassembled, it could be confirmed that the negative electrode active material 2b peeled off from the negative electrode plate 2 and removed from the conductive network was deposited on the bottom of each cell chamber 5a. Therefore, it is understood that it is preferable to enclose the negative electrode plate 2 in the bag-like separator 3.

  Although the present invention has been described above by the preferred embodiments, such description is not a limitation and, of course, various modifications are possible. For example, similarly to the negative electrode grid 2a, the positive electrode grid 1a may be produced by a punching method in which holes are formed in a lead alloy sheet containing 1 ppm to 300 ppm bismuth and 400 ppm to 1000 ppm calcium, Needless to say.

  The present invention is useful in a lead-acid battery used for an automobile that performs idling stop control.

DESCRIPTION OF SYMBOLS 1 positive electrode plate 1a positive electrode grid 1b positive electrode active material 2 negative electrode plate 2a negative electrode grid 2b negative electrode active material 3 separator 4 electrode plate group 5 battery case 5a cell chamber 6 lid

Claims (4)

A positive electrode plate comprising a positive electrode grid and a positive electrode active material;
A negative electrode plate comprising a negative electrode grid and a negative electrode active material;
An electrode plate group in which a positive electrode plate and a negative electrode plate are laminated via a separator;
A battery case having a plurality of cell chambers for storing the electrode plate group and the electrolytic solution;
And a lid for sealing the opening of the battery case.
The positive electrode grid or at least one of said negative electrode grid, Ru is produced by punching system drilling a hole in the lead alloy sheet containing 300ppm or less of bismuth and 700 ppm or 1000ppm or less of calcium than 1 ppm, the manufacturing method of the lead-acid battery. The method for producing a lead-acid battery according to claim 1, wherein the negative electrode grid is manufactured by a punching method in which a hole is formed in a lead alloy sheet containing 1 ppm to 300 ppm bismuth and 700 ppm to 1000 ppm calcium . The electrolyte comprises the following aluminum ion 0.02 mol / L or more 0.2 mol / L, the manufacturing method of the lead-acid battery according to claim 1 or 2. The method of manufacturing a lead storage battery according to any one of claims 1 to 3 , wherein the bag-like separator encloses the negative electrode plate.

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