JP2012074279A - Lead acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a lead acid battery having the same number of positive electrode plate as a negative electrode plate and an electrolyte containing an Al ion of 0.02 to 0.2 mol/L and a Li ion of 0.02 to 0.2 mol/L.SOLUTION: The lead acid battery which maintains high rate discharge performance with acceptance of regenerative charging to be improved is provided.

Description

  The present invention relates to a lead storage battery, and more particularly, to a lead storage battery for automobiles or the like in which the same number of positive and negative electrode plates are arranged and used in PSOC (Partial State of Charge).

  A lead storage battery in which the same number of positive and negative electrode plates are arranged for the purpose of improving energy density or reducing the weight is known. Patent Document 1 points out that in such a lead storage battery, the polarization of the negative electrode becomes significant during charging, and the regenerative charge acceptability decreases. And in patent document 1 (JP2009-104914A), it proposes preventing the life fall by insufficient charge by optimizing the amount of carbon and the amount of barium sulfate in a negative electrode active material, and optimizing the size of a positive electrode and a negative electrode. Yes.

  Patent Document 2 (JP3713947B) discloses that the characteristics change depending on whether the positive electrode plate or the negative electrode plate is arranged on the side wall side of the battery case when the number of the negative electrode plate and the positive electrode plate is the same. . And it discloses disposing the positive electrode plate which is easily influenced by the external temperature on the side far from the side wall.

  In Patent Document 3 (JP2008-243487A), in a normal lead-acid battery having one negative electrode plate larger than the positive electrode plate, 0.005 to 0.14 mol / L of Li ion is added to the electrolyte, and 0.01 to 0.3 mol / L of Al ion is added. L is disclosed. Patent Document 3 discloses that the positive electrode utilization rate is increased by Li ions, and sulfation can be prevented by Al ions. Patent Document 4 (JPS52-136332A) is similar to Patent Document 3. It discloses that sulfation can be prevented by Al ions.

  The inventor studied to improve the regenerative charge acceptability with an additive to the electrolytic solution for lead storage batteries having the same number of positive and negative electrode plates, and reached the present invention.

JP2009-104914A JP3713947B JP2008-243487A JPS52-136332A

  An object of the present invention is to improve regenerative charge acceptance and maintain a high rate discharge performance by using an additive to an electrolytic solution for a lead storage battery having the same number of positive and negative electrode plates.

  The present invention relates to a lead storage battery in which an electrode plate group composed of the same number of positive and negative electrode plates is immersed in a dilute sulfuric acid electrolyte solution, wherein the electrolyte solution is 0.02 to 0.2 mol / L Al ions, It contains 0.02 to 0.2 mol / L Li ion.

  Table 1 shows the results when the number of the negative plates and the positive plates in the example is the same, and Table 2 shows the results when the number of the negative plates is one more than that of the positive plates. In any case, Al ions improve the regenerative charging performance and reduce the high rate discharge performance, but when the negative electrode plate is more than the positive electrode plate, the improvement of the regenerative charging performance by Al ions is slight. On the other hand, when the number of the negative electrode plates and the positive electrode plates is the same, the regenerative charging performance is significantly improved by Al ions. This shows that Al ions in the electrolyte are extremely effective when the negative electrode plate and the positive electrode plate are made to have the same number and the polarization of the negative electrode advances and the regenerative charge acceptance decreases. Yes. Even when the number of the positive and negative electrode plates is the same or when the number of the negative electrode plates is one, the Al ions in the electrolytic solution deteriorate the high rate discharge characteristics. On the other hand, when Li ions are added in addition to Al ions, the high rate discharge performance can be maintained at or above the allowable value.

  As shown in Table 1 and FIG. 2, the effect of Al ions on regenerative charge acceptability becomes significant at 0.02 mol / L or more. On the other hand, the high rate discharge performance is significantly reduced when Al ions are added in excess of 0.2 mol / L. Therefore, the Al ion concentration is 0.02 mol / L or more and 0.2 mol / L or less. Further, as shown in Table 1 and FIG. 3, the effect of Li ions on the high rate discharge performance becomes remarkable at 0.02 mol / L or more. On the other hand, regenerative charge performance is significantly reduced when Li ion is added in excess of 0.2 mol / L. Therefore, the Li ion concentration is also 0.02 mol / L or more and 0.2 mol / L or less. As described above, according to the present invention, in a lead storage battery having the same number of positive and negative electrode plates, high regenerative charge acceptance can be achieved, and high rate discharge performance can be set within a permissible range.

In this specification, the concentration of Al ions and Li ions is expressed as the concentration of Al ions and Li ions per mol of electrolyte (mol / L). One mole of Al ions corresponds to 171.05 g of aluminum sulfate (Al ₂ (SO ₄ ) ₃ ). The composition of the active material is shown excluding water, sulfuric acid, and impurities. In principle, the concentration range includes an upper limit and a lower limit. For example, 0.02 to 0.2 mol / L means 0.02 mol / L or more and 0.2 mol / L or less.

Schematic diagram of the lead storage battery of the example Characteristic diagram showing the effect of Al ion concentration on regenerative charge acceptance and high rate discharge performance when Li ion concentration in electrolyte is fixed at 0.1 mol / L or 0.2 mol / L Characteristic diagram showing the effect of Li ion concentration on regenerative charge acceptance and high rate discharge performance when Al ion concentration in electrolyte is fixed at 0.1 mol / L or 0.2 mol / L

  Hereinafter, an optimum embodiment of the present invention will be described. In carrying out the present invention, the embodiments can be appropriately changed in accordance with common sense of those skilled in the art and disclosure of prior art.

Best practice

Manufacture of lead-acid batteries
A lead-acid battery of 55B24 type with the same number of positive and negative plates was manufactured in accordance with JIS D5301. The nominal voltage is 12V, and the 5 hour rate rated capacity is 36Ah. The positive electrode lattice contains 0.07 mass% Ca, 1.5 mass% Sn and unavoidable impurities, and the balance is Pb. The negative electrode lattice contains 0.05 mass% Ca, 0.5 mass% Sn, and inevitable impurities, and the remainder is Pb. Each grid has a height of 115 mm, a width of 100 mm, and a thickness of 1 mm, and may be an expanded grid or a cast grid.

  0.1 mass% of acrylic fiber as a reinforcing agent was added to the lead powder produced by the ball mill method (total of 100 mass% with the lead powder). 100 mass% of this mixture was mixed with 13 mass% of water and 10 mass% of dilute sulfuric acid having a specific gravity of 1.40 at 20 ° C. to obtain a positive electrode active material paste. The reinforcing agent is not limited to acrylic fiber, and any reinforcing agent may not be added. Acrylic fibers of lignin 0.15 mass%, carbon black 0.2 mass%, barium sulfate 0.5 mass%, and 0.1 mass% were added to the lead powder produced by the ball mill method, and the total with the lead powder was 100 mass%. 11 mass% of water and 7 mass% of dilute sulfuric acid having a specific gravity of 1.40 at 20 ° C. were mixed with 100 mass% of this mixture to obtain a negative electrode active material paste. The lead powder is not limited to the ball mill method, but may be produced by a Burton method or the like, and the composition of the positive electrode active material paste and the negative electrode active material paste is arbitrary.

  Each of the positive electrode plate and the negative electrode plate was filled with 50 g of each active material paste, aged at 50 ° C. and 50% relative humidity for 48 hours, and then dried in a dry atmosphere at 50 ° C. for 24 hours. The negative electrode plate was accommodated in a bag-like polyethylene separator, the positive electrode plate and the negative electrode plate were alternately arranged, and the ears of the same polarity electrode plate were welded together to form an electrode plate group. Six obtained electrode plate groups are housed in a polypropylene battery case, welded so as to be connected in series at the strap portion, and a predetermined amount of Al sulfate and Li sulfate are added to dilute sulfuric acid with a specific gravity of 1.23 at 20 ° C. Was added, and a battery case was formed in a water bath at 25 ° C. to obtain a 55B24 type lead acid battery. Al ion source and Li ion source are optional, for example, Al ion source can be added in any form such as metal Al, aluminum hydroxide, aluminum sulfate, etc., Li ion source can be added in any form such as lithium hydroxide, lithium sulfate, lithium carbonate, etc. .

  A lead storage battery is schematically shown in FIG. 1, wherein 2 is an electrode plate group and includes the same number of positive electrode plates 4 and negative electrode plates 6, and 8 encloses the negative electrode plate 6 with a separator, but the positive electrode plate 4 may be encapsulated. . For example, the seven positive plates 4 are electrically connected to each other by the strap 10, and similarly, the seven negative plates 6 are also electrically connected to each other by the strap 12. Further, a separator that separates the positive electrode plate 4a at the end from the side wall of the battery case may be provided. The electrode plate group 2 is immersed in a dilute sulfuric acid electrolyte solution in a battery case, and a plurality of electrode plate groups are connected in series to constitute a lead storage battery. Here, “dilute sulfuric acid type” means that Al ions, Li ions, etc. are dissolved in dilute sulfuric acid.

  A lead storage battery of Example 1-16 was produced in the same manner except that the Al ion concentration and the Li ion concentration were changed. Further, the lead ion battery of Comparative Example 1-9 was prepared in the same manner as in the example except that the Al ion concentration or the Li ion concentration was excluded from the range of the example. Further, a lead storage battery of Comparative Example 10-17 was prepared in the same manner as in the Example except that the number of the positive electrode plates was 7 and the number of the negative electrode plates was 8, and the Al ion concentration and the Li ion concentration were changed.

Performance test and results A regenerative charge test and a high rate discharge performance test (JIS D5301: 2006, 9.5.3b)) were conducted for each lead-acid battery. In the regenerative charge test, the battery was discharged from a fully charged state in a 25 ° C. tank for 30 minutes with a 5-hour rate current, and the state of charge (SOC) was 90%, and left for 12 hours. Next, constant voltage charging was performed for 10 seconds at 14.4 V (maximum current 100 A) in a 25 ° C. air tank, and the amount of electricity charged for 10 seconds was measured. In addition, in order to evaluate the high rate discharge performance, a high rate discharge characteristic test of JIS D5301 was conducted, and the discharge duration until the terminal voltage decreased to 6V was obtained. Table 1 shows the results when both the positive and negative electrode plates were used. Table 1 shows the results when the Li ion concentration was fixed at 0.1 mol / L or 0.2 mol / L and the Al ion concentration was changed. It is shown in 2. Fig. 3 shows the results when the Li ion concentration was changed with the Al ion concentration fixed at 0.1 mol / L or 0.2 mol / L.

  In Table 1 and the like, the results are shown as relative values with Comparative Example 1 in which neither Al ions nor Li ions are added as 100, the target value of regenerative charging performance is 115 or more, and the allowable value of high rate discharge performance is 95 or more. The number of samples is 3, and the results are shown as average values. Table 2 shows the results when 8 negative plates and 7 positive plates were used. Similarly, the number of samples is 3, and the results are shown as average values.

  As is apparent from Table 1 and FIG. 2, the addition of Al ions to the electrolyte significantly improves the regenerative charging performance, and there is a large difference between the addition amount 0 and the addition amount 0.02 mol / L. The regenerative charging performance still increases with the Al ion concentration, but if it exceeds 0.2 mol / L, the high rate discharge performance falls below the allowable lower limit. Moreover, Li ion recovers the high rate discharge performance that was lowered by the addition of Al ion, and already has a remarkable effect when 0.02 mol / L is added, and if it exceeds 0.2 mol / L, the regenerative charging performance decreases rapidly. The range in which good results are obtained in both regenerative charge performance and high rate discharge performance is 0.02 to 0.2 mol / L for Al ions and 0.02 to 0.2 mol / L for Li ions.

  Al ions are considered to improve regenerative charge acceptance by suppressing the polarization of the negative electrode during charging. Al ions are known to suppress sulfation of the negative electrode (Patent Documents 3 and 4), and are considered to facilitate the decomposition of lead sulfate at the negative electrode during charging and suppress the polarization of the negative electrode. However, when the number of positive plates and the number of negative plates is the same, the addition of Al ions has a particularly remarkable effect as compared with the case where the number of negative plates is one more than that of the positive plates. On the other hand, when only Al ions are added to dilute sulfuric acid, when sulfate ions and protons are consumed in the vicinity of the active material by high rate discharge, it is considered that the conductivity is insufficient in the vicinity of the electrolyte / active material interface. On the other hand, Li ions are ions with a small ionic radius and high electrical conductivity, and can move through the active material, thus suppressing a decrease in the conductivity of the electrolyte during high rate discharge and maintaining high rate discharge performance. It is thought that.

  The electrolytic solution may contain Na ions, K ions, and the like derived from the lignin of the negative electrode. The allowable ranges are 0.015 mol / L or less for Na ions and 0.01 mol / L or less for K ions. Furthermore, the electrolytic solution may contain Sn ions, Sb ions, etc. derived from the positive electrode plate and the negative electrode plate, phosphate ions, silica, and the like.

The embodiment has the following characteristics.
1) By containing 0.02 to 0.2 mol / L of Al ions, the regenerative charge acceptability in the lead storage battery having the same number of positive and negative electrode plates can be remarkably improved (Table 1). As a result, the performance of the lead storage battery in the PSOC state is improved, and a lead storage battery particularly suitable for an idling stop vehicle can be obtained.
2) On the other hand, when the number of negative electrode plates is one more than that of the positive electrode plates (Table 2), the improvement in regenerative charge acceptance by Al ions is slight. Is different.
3) When Al ions are added, the high rate discharge performance is lowered, but by containing 0.02 to 0.2 mol / L Li ions, the high rate discharge performance can be maintained within an allowable range.
4) By using the same number of positive and negative electrode plates, it is possible to improve energy density or reduce the weight of the storage battery.

2 Electrode plate group 4 Positive electrode plate 6 Negative electrode plate 8 Separator 10 Positive electrode strap 12 Negative electrode strap

Claims (1)

In a lead storage battery in which an electrode plate group composed of the same number of positive and negative electrode plates is immersed in a dilute sulfuric acid electrolyte,
The lead acid battery characterized by the said electrolyte solution containing 0.02-0.2 mol / L Al ion and 0.02-0.2 mol / L Li ion.