JP6203472B2 - Lead acid battery - Google Patents

Description

  The present invention relates to a lead storage battery.

For the purpose of improving the fuel efficiency of automobiles, automobiles equipped with a charge control function for controlling charging of a storage battery or an idling stop function for stopping an engine when stopped are becoming widespread. In such an automobile, since it is used in a state where charging is insufficient, lead storage batteries tend to have a short life due to sulfation in which lead sulfate accumulates on the negative electrode. On the other hand, the inventor reduced the density of the electrolytic solution to, for example, 1.265 g / cm ³ or less, and contained lead sulfate in the negative electrode by containing a predetermined amount of aluminum ions and lithium ions in the electrolytic solution. It has been found that the low temperature HR performance can be improved with a particularly small amount. The low temperature HR performance represents the performance of the storage battery when starting the engine at a low temperature, and can be evaluated by, for example, the low temperature HR capacity.

As for related prior art, Patent Document 1 (WO2007 / 36979) is superior in idling stop life and battery capacity (5-hour rate capacity) by containing aluminum ions and lithium ions in the electrolytic solution. It discloses that a lead-acid battery is obtained. However, the influence of the density of the electrolytic solution has not been studied, and only mentions a storage battery in which the negative electrode contains carbon black and contains an aluminum ion and has a density of 1.28 g / cm ³ .

WO2007 / 36979

A basic object of the present invention is to provide a lead storage battery that has low accumulation of lead sulfate and improved low-temperature HR performance on the basis of a lead storage battery having the same electrolyte density .

The present invention relates to a lead-acid battery in which an electrode plate group in which a separator is interposed between a positive electrode plate and a negative electrode plate is accommodated in a battery case, and the electrolyte solution is held in the battery case. The density in the fully charged state at ℃ is 1.265 g / cm ³ or less 1.200 g / cm ³ or more , aluminum ions 0.02 mol / L or more and 0.2 mol / L or less, lithium ions 0.02 mol / L or more and 0.2 mol / L L or less is contained.

Most preferably, the density in a fully charged state at 20 ° C. is 1.260 g / cm ³ or less and 1.230 g / cm ³ or more. The fully charged state refers to a state in which the charging rate is substantially 100%. For example, a full charged state can be obtained by charging about 150% of the rated capacity with a 10 hour rate current. The type of the lead storage battery may be a control valve type lead storage battery in addition to the liquid lead storage battery of the embodiment. Hereinafter, the density of the electrolytic solution represents the density in a fully charged state at 20 ° C.

The effect of aluminum ions and lithium ions on the electrolyte of lead-acid batteries changes at the electrolyte density of 1.265 g / cm ³ . That is, the difference between the electrolytic solution containing neither aluminum ions nor lithium ions and the electrolytic solution containing aluminum ions and lithium ions is particularly large when the density of the electrolytic solution is 1.265 g / cm ³ or less. When the density of the electrolytic solution is 1.265 g / cm ³ or less, the accumulation of lead sulfate is particularly reduced by containing aluminum ions and lithium ions. For this reason, the idling stop life performance can be further improved.

When the density of the electrolytic solution is reduced, discharge performance at a large current generally decreases, and in the case of a lead storage battery for automobiles, a decrease in low-temperature HR performance becomes a problem. However, in an electrolyte containing appropriate amounts of aluminum ions and lithium ions , low-temperature HR is based on the case where the electrolyte has the same density but contains neither aluminum ions nor lithium ions , even though the density of the electrolyte is reduced. Performance can be improved. This is because when the density of the electrolytic solution is small, the combination of aluminum ions and lithium ions significantly improves the low temperature HR performance.

The effect of aluminum ions and lithium ions when the electrolyte density is 1.265 g / cm ³ or less will be described. When lithium ions of 0.02 mol / L or more and 0.2 mol / L or less are contained, the effect of aluminum ions becomes significant at a concentration of 0.02 mol / L or more. Lead accumulation can be significantly reduced. Also, if the aluminum ion concentration exceeds 0.2 mol / L, lead sulfate accumulation may increase rather, and the low-temperature HR performance will also deteriorate. When aluminum ions of 0.02 mol / L or more and 0.2 mol / L or less are included, increasing the lithium ion concentration from 0.01 mol / L to 0.02 mol / L significantly improves the low-temperature HR performance and reduces the amount of lead sulfate accumulation To do. Even if the lithium ion concentration exceeds 0.2 mol / L, the performance is not improved and the amount of lead sulfate accumulation may increase. And lithium resources are limited, and overuse is not preferable.

If the density of the electrolyte is less than 1.200 g / cm ^3, since such a shortage of low-temperature HR performance, the density of the electrolyte solution is preferably 1.200 g / cm ³ or more, particularly 1.230g / cm ³ or more. The improvement in low-temperature HR performance due to the combination of aluminum ions and lithium ions, based on the case of containing no aluminum ions and lithium ions, is greater at 1.250 g / cm ³ than at 1.265 g / cm ^3. Is preferably 1.260 g / cm ³ or less and most preferably 1.230 g / cm ³ or more.

Characteristic chart showing the density in a fully charged state at 20 ° C, the low-temperature HR capacity, and the amount of lead sulfate accumulated after an idling stop life test in an electrolyte containing 0.1 mol / L lithium ions and 0.05 mol / L aluminum ions

  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.

  Synthetic resin fibers are added to the lead powder produced by the ball mill method, and water and dilute sulfuric acid are added to make a paste. The Pb-Ca-Sn positive electrode lattice is filled with aging and drying, and the unformed positive electrode plate It was. Synthetic resin fibers, barium sulfate, carbon black and lignin are added to the lead powder produced by the ball mill method, and water and dilute sulfuric acid are added to form a paste, which is then filled into a Pb-Ca-Sn negative electrode lattice and aged and dried. To give an unformed negative electrode plate. The unformed negative electrode plate was wrapped with a microporous, bag-like polyethylene separator, and 8 unformed negative electrode plates and 7 unformed positive electrode plates were accommodated in a battery case.

Aluminum sulfate and lithium sulfate are added so that the aluminum ion content and the lithium ion content are 0 to 0.3 mol / L, respectively, and the density at 20 ° C. is 1.290 to 1.200 g in a fully charged state after chemical conversion. Dilute sulfuric acid having a density changed so as to be / cm ³ was prepared. This dilute sulfuric acid was poured into a battery case, and a battery case was formed in a 25 ° C. water tank to obtain a D23 size lead-acid battery. The material and manufacturing method of the positive and negative grids are arbitrary, and the lead powder is not limited to the one based on the ball mill method, but may be one based on the Barton method or the like, and the content of the lead tan is arbitrary. Further, the amount and type of additives to the lead powder, the content of impurities, etc. are arbitrary. The kind of compound for containing aluminum ion and lithium ion is arbitrary. Each sample was manufactured under the same conditions except for the density of the electrolytic solution, the aluminum ion content, and the lithium ion content.

  Prepare three storage batteries with the same density and composition of the electrolyte, conduct a low-temperature HR discharge test (9.5.3b of JIS D 5301: 2006), and the terminal voltage drops to 6V when discharged at -15 ° C and 300A. The discharge duration until it was measured was measured. After the low-temperature HR discharge test, the storage battery was fully charged and an idling stop life test was conducted at 50 ° C. According to the Battery Industry Association Standard, the idling stop life test was repeated at 45 ° C for 59 seconds at 25 ° C, 300 A for 1 second, and charged and discharged for 60 seconds at 14 V for 40 to 48 hours every 3600 cycles. The storage battery is left unattended (SBA S 0101: 2006). Here, the ambient temperature was changed to 50 ° C. for the test. This is because low-density electrolytes tend to accumulate lead sulfate at high temperatures and, depending on the season and region, the temperature in the engine compartment of an automobile can be over 50 ° C. Then, charging / discharging in the idling stop life test was stopped at 25200 cycles, the storage battery was disassembled, and the amount of lead sulfate accumulation in the negative electrode was measured.

  The results are shown in Table 1 with the average values of the three storage batteries. The results are shown when the aluminum ion content is fixed at 0.05 mol / L and the lithium ion content is fixed at 0.1 mol / L, and the density of the electrolyte is changed. It is shown in 1. The results are shown as relative values with the comparative example having the same density of the electrolytic solution and containing neither aluminum ions nor lithium ions as 100. When both the aluminum ion content and the lithium ion content are 0, the lower the electrolyte density, the lower the amount of lead sulfate accumulated and the lower the low-temperature HR performance.

The main results are shown in FIG. In electrolytes containing both aluminum ions and lithium ions, if the density is reduced from 1.280 g / cm ³ to 1.265 g / cm ³ , the accumulation of lead sulfate is significantly reduced, and even if the density of the electrolyte is further reduced, The accumulation of lead sulfate is almost the same. With low-temperature HR capacity, the effect of aluminum ions and lithium ions increases as the electrolyte density decreases until the density reaches 1.230 g / cm ^3, improving low-temperature HR performance based on the case where these ions are not contained. To do.

When the density of the electrolyte is fixed at 1.265 g / cm ³ , which is a typical condition in the examples, the lithium ion concentration is fixed at 0.1 mol / L, and the aluminum ion concentration is changed, 0.01 mol / L and 0.02 The amount of lead sulfate accumulation changes rapidly between mol / L. And the accumulated amount of lead sulfate decreases with aluminum ion concentration up to 0.2 mol / L, but conversely increases at 0.3 mol / L. The low-temperature HR capacity decreases greatly when the aluminum ion concentration is increased from 0.2 mol / L to 0.3 mol / L. Therefore, the aluminum ion concentration is set to 0.02 mol / L to 0.2 mol / L. In these respects, the same tendency is shown when the density of the electrolytic solution is fixed at 1.230 g / cm ³ .

The density of the electrolyte was fixed to 1.265 g / cm ^3, to fix the aluminum ion concentration to 0.05 mol / L, when changing the lithium ion concentration, up to 0.05 mol / L is accumulation of lead sulfate with lithium ion concentration Although it decreases, it increases conversely at 0.2 mol / L or more. The low-temperature HR capacity reaches its maximum at a lithium ion concentration of 0.05 mol / L, and does not improve even if the lithium ion concentration is increased further. Therefore, the lithium ion concentration is changed from 0.02 mol / L to 0.2 mol / L. When the density of the electrolyte is fixed at 1.230 g / cm ³ and the aluminum ion concentration is fixed at 0.05 mol / L, the performance of the storage battery improves with the lithium ion concentration up to 0.2 mol / L. Therefore, the lithium ion concentration is set to 0.02 mol / L to 0.2 mol / L.

Even in storage batteries with an electrolyte density of 1.250 g / cm ³ or 1.200 g / cm ³ , the lithium ion concentration is 0.02 mol / L or more and 0.2 mol / L or less, and the aluminum ion concentration is 0.02 mol / L or more and 0.2 mol / L. Below L, similar results are obtained.

Claims (1)

A lead-acid battery for an automobile having an idling stop function in which an electrode plate group in which a separator is interposed between a positive electrode plate and a negative electrode plate is accommodated in the battery case, and an electrolytic solution is held in the battery case. In
The electrolyte has a density of 1.265 g / cm ³ or less and 1.200 g / cm ³ or more in a fully charged state at 20 ° C., 0.02 mol / L to 0.2 mol / L of aluminum ions, and 0.02 mol / L of lithium ions. The lead acid battery characterized by containing 0.2 mol / L or less above.

Images