JP2005268061A - Lead storage cell - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lead storage cell having a proper cycle life time suitable for automobiles, introducing an idling stop system, and having an overcharge-preventing system or the like. <P>SOLUTION: The lead storage cell is such that includes 0.005 to 0.1 weight parts (weight parts per 100 weight parts of a negative electrode active material) of Zn when metal converted on a negative electrode plate, and 2 to 50 g/liter of Al when sulfate converted in electrolyte solution. Also, the lead storage cell contains 0.06 to 1.4 g/liter of Zn when metal converted, and 2 to 50 g/liter of Al when sulfate converted in the electrolyte solution. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  In particular, the present invention relates to a lead-acid battery excellent in cycle life, which is suitable for an automobile (new system introduction vehicle) in which a new system such as an idle stop system or an overcharge prevention system is introduced.

  Lead-acid batteries for automobiles, as called SLI batteries, are mainly used for starter start-up, lighting, and ignition at start-up, and are also used for the power supply of more than 100 motors in luxury cars. In addition to starting the starter at the time of starting, the engine drives the generator to supply power, so that the lead-acid battery was not discharged so deeply. Further, since the lead storage battery is charged by a generator, it is often placed in a fully charged state and has been required to be resistant to overcharging.

  However, in recent years, automobiles are strongly required to improve fuel consumption and exhaust emissions, and new systems such as an idle stop system and an overcharge prevention system have been introduced accordingly.

The idling stop system is a system that mainly stops exhaust gas by stopping the engine when a vehicle is stopped by a signal or the like, and starting the engine quickly when starting.
However, in this system, when the engine is stopped, power is supplied from the lead storage battery because the supply from the generator is interrupted, and therefore the lead storage battery is deeply discharged as compared with the conventional case.

The overcharge prevention system is a system that terminates charging before overcharging and saves charging energy. According to this system, the load on the generator, the decrease in electrolyte due to overcharging, the corrosion of the positive grid, etc. Is also improved.
However, in this system, a lead storage battery whose charging efficiency has been lowered is used in a state of insufficient charging (so-called PSOC) for a long period of time.

  In this way, in the new system introduction vehicle, the lead-acid battery is used in a deep discharge and chronic undercharged state, so the battery life is remarkably shortened. In particular, long-term use in an insufficiently charged state is likely to cause sulfation (a phenomenon in which lead sulfate is densely crystallized on the negative electrode surface), resulting in a vicious circle in which the charging efficiency of the negative electrode is reduced and the charging shortage further proceeds. Become.

  As a sulfation prevention measure, there has been proposed a method (Non-patent Document 1, Patent Document 1) in which a large amount of carbon is added to the negative electrode plate, and the carbon penetrates into the gap between the lead sulfates to form a conductive path.

Journal of Power Sources Vol.59 (1996) 153-157 JP-A-7-201331

However, even with the method of adding a large amount of carbon, the lead-acid battery has not been able to obtain a sufficient life improvement effect in the new system introduction vehicle.
For this reason, the present inventors have studied the improvement of the life of lead-acid batteries in vehicles equipped with the new system. Lead-acid batteries containing Zn (zinc) and Al (aluminum) in the negative electrode plate or electrolyte solution have reduced sulfation. As a result, the inventors have found that a sufficiently long life can be obtained even when the vehicle is introduced into a new system, and have further advanced research to complete the present invention.

  An object of the present invention is to provide a lead-acid battery having a long life even when used in a vehicle incorporating a new system.

  According to the first aspect of the present invention, Zn is contained in the negative electrode plate in an amount of 0.005 to 0.1 parts by weight in terms of metal (parts by weight per 100 parts by weight of the negative electrode active material), and Al in the electrolyte is 2 to 2 in terms of sulfate. It is a lead storage battery characterized by containing 50 g / liter.

  The invention according to claim 2 is a lead storage battery characterized in that the electrolyte contains 0.06 to 1.4 g / liter of Zn in terms of metal and 2 to 50 g / liter of Al in terms of sulfate. is there.

  According to a third aspect of the invention, the negative electrode plate contains 0.005 to 0.1 parts by weight of Zn in terms of metal (parts by weight per 100 parts by weight of the negative electrode active material), and the electrolyte contains 0.06 in terms of metal. A lead acid battery containing ˜1.4 g / liter and containing 2 to 50 g / liter of Al in terms of sulfate.

  A fourth aspect of the present invention is the lead acid battery according to any one of the first to third aspects, wherein the electrolytic solution is a sulfuric acid aqueous solution having a specific gravity at 20 ° C. of 1.250 to 1.320.

Since the lead storage battery of the present invention contains an appropriate amount of Zn in the negative electrode plate and / or electrolyte and an appropriate amount of Al in the electrolyte, sulfation is suppressed by the synergistic effect of Zn and Al, deep discharge and chronic Even if it is used for a vehicle with a new system that is used in a state of insufficient charging, a sufficiently long life can be obtained.
When the sulfuric acid aqueous solution having a specific gravity of 1.250 to 1.320 at 20 ° C. is used as the electrolytic solution, the lead storage battery of the present invention has good battery characteristics and a stable synergistic effect of Zn and Al. It is done.

  The lead storage battery of the present invention makes the lead sulfate crystallized on the negative electrode plate finer or unstable due to the synergistic effect of Zn contained in the negative electrode plate and / or electrolyte and Al contained in the electrolyte. It suppresses sulfation, thereby improving the charge / discharge efficiency of the negative electrode.

  In the first aspect of the present invention, the amount of Zn contained in the negative electrode plate is regulated to 0.005 to 0.1 parts by weight (parts by weight per 100 parts by weight of the negative electrode active material) in terms of metal, and Al contained in the electrolytic solution The reason for prescribing the amount of 2 to 50 g / liter in terms of sulfate is that the sulfation cannot be sufficiently suppressed no matter which is below the lower limit, and the effect is saturated and the cost is saturated even if any exceeds the upper limit. This is because it is disadvantageous. Further, excess Zn causes a decrease in hydrogen overvoltage and an increase in self-discharge, and excess Al causes a decrease in conductivity of the electrolyte (increase in internal resistance), resulting in a decrease in battery capacity.

  In the invention according to claim 2, the reason why the content of Zn to be contained in the electrolytic solution is specified to be 0.06 to 1.4 g / liter in terms of metal is that sulfation cannot be sufficiently suppressed even if the content falls below the lower limit value. This is because even if the value exceeds the upper limit, the effect is saturated. The reason why the content of Al is regulated to 2 to 50 g / liter in terms of sulfate is the same as that of the first aspect of the present invention.

  The invention described in claim 3 is a lead storage battery in which Zn is contained in an appropriate amount in the negative electrode plate and the electrolyte solution, and Al is contained in the electrolyte solution in an appropriate amount. Same as in the description invention.

  In the present invention, in order to contain Al in the electrolytic solution, in addition to the method of previously dissolving in the electrolytic solution, for example, a method of containing Al sulfate in the negative electrode plate and dissolving it at the time of injecting the electrolytic solution can be applied. .

  In the present invention, the negative electrode plate may contain carbon, lignin, barium sulfate or the like as necessary. The amount thereof is suitably 0.05 to 3 parts by weight, 0.1 to 1 part by weight, and 0.5 to 5 parts by weight, respectively, per 100 parts by weight of the negative electrode active material. The effect cannot be sufficiently obtained, and even if the content exceeds the upper limit, the effect is saturated and disadvantageous in cost.

  In the present invention, it is desirable to use an aqueous sulfuric acid solution having a specific gravity at 20 ° C. of 1.250 to 1.320 as the electrolytic solution. The reason is that when the specific gravity is less than the lower limit (1.250), the amount of sulfate ions is insufficient, and when the specific gravity exceeds the upper limit (1.320), the charging efficiency is lowered, and in any case, the capacity is insufficient. This is because if the upper limit is exceeded, gas is generated and the electrolytic solution tends to decrease.

  Even if the lead storage battery of the present invention is used for power storage, stationary backup, etc., the same long life effect as described above can be obtained. Further, even if the present invention is applied to a sealed lead-acid battery, a long life effect can be obtained.

  Hereinafter, the present invention will be specifically described by way of examples.

  The required number of unformed negative electrode plates and unformed positive electrode plates are alternately laminated with a polyethylene separator interposed therebetween, and the electrode plates of this laminate are welded together by the COS method to form an electrode plate group. Put the lid into the battery case, heat-seal, inject an electrolyte containing various amounts of Al sulfate into a sulfuric acid aqueous solution with a specific gravity of 1.10 from the liquid port of the lid, and then put the battery case into a 40 ° C. water tank The battery is overcharged by 200% of the theoretical capacity to form a battery case, and then the specific gravity of the electrolyte is adjusted to the range of 1.250 to 1.320, and then fully charged at 25 ° C. for 5 hours with a current. A 2V lead acid battery was manufactured. The 5-hour rate capacity of this battery was 50 Ah. The amount of Al sulfate was changed within the specified range of the present invention.

The unformed negative electrode plate is obtained by adding predetermined amounts of Zn oxide powder having an average particle diameter of 1 μm, acetylene black (carbon) powder and barium sulfate powder having a specific surface area of 70 m ² / g to lead oxide prepared by a ball mill method. A predetermined amount of an aqueous solution in which lignin is dissolved is added to the obtained mixed powder, and a negative electrode active material paste is prepared by kneading while adding a predetermined amount of ion-exchanged water. This paste is cast into a Pb-Ca alloy. A substrate was filled, and this was aged in an atmosphere of a temperature of 40 ° C. and a humidity of 95% for 24 hours and then dried.

The added amount of the Zn oxide powder was variously changed within the specified value of the present invention.
The carbon powder, barium sulfate powder, and lignin were added at 0.5, 0.5, and 1.0 parts by weight per 100 parts by weight of the negative electrode active material, respectively. About 10 parts by weight of the ion-exchanged water was added to 100 parts by weight of the lead oxide, and 10 parts by weight of diluted sulfuric acid was added. The ion exchange water was added so that the cup density of the negative electrode active material paste was about 140 g / 2 in ³ .

The unformed positive electrode plate was kneaded by adding 10 parts by weight of ion-exchanged water to 100 parts by weight of lead oxide, and subsequently adding 10 parts by weight of dilute sulfuric acid having a specific gravity of 1.27, and a paste for positive electrode having a cup density of 140 g / 2 in ³ The paste was filled in a Pb—Ca alloy cast substrate, then aged in an atmosphere of 40 ° C. and 95% humidity for 24 hours, and then dried.

  For each of the obtained lead storage batteries, after being fully charged at a temperature of 25 ° C. at a current rate of 5 hours, at the same atmospheric temperature, [60 A, constant current discharge for 60 seconds] → [60 A, 60 seconds, upper limit voltage 2.33 V Endurance acceleration test with a constant current / constant voltage charge] as one cycle, and the number of cycles at the time when the voltage during discharge fell below 1.6 V / cell was defined as the life. A cycle life number of 4900 or more was considered acceptable.

  Example 1 is the same as Example 1 except that an electrolytic solution in which various amounts of Al sulfate and Zn sulfate are dissolved in the sulfuric acid aqueous solution having a specific gravity of 1.10 is used, and the lead oxide does not contain Zn oxide powder. A lead storage battery was manufactured by the method, and the cycle life number was measured by the same method as in Example 1. The amount of Zn sulfate was within the specified value of the present invention.

  In Example 1, a lead storage battery was manufactured by the same method as in Example 1 except that various amounts of Al sulfate and Zn sulfate were dissolved in the sulfuric acid aqueous solution having a specific gravity of 1.10. Number was measured. The amount of Zn sulfate was within the specified value of the present invention.

  In Example 1, except that the specific gravity of the electrolyte was adjusted to 1.240 or 1.330, a lead storage battery was manufactured by the same method as in Example 1, and the cycle life number was measured by the same method as in Example 1.

  In Example 2, the lead acid battery was manufactured by the same method as Example 2 except having adjusted the specific gravity of electrolyte solution to 1.240 or 1.330, and the cycle life number was measured by the same method as Example 2. FIG.

(Comparative Example 1)
In Example 1, a lead storage battery was manufactured by the same method as in Example 1 except that the contents of Zn and Al were outside the specified values of the present invention, and the cycle life number was measured by the same method as in Example 1.

(Comparative Example 2)
In Example 2, a lead storage battery was manufactured by the same method as in Example 2 except that the contents of Zn and Al were outside the specified values of the present invention, and the cycle life number was measured by the same method as in Example 2.

The cycle life numbers of Examples 1 to 5 and Comparative Examples 1 and 2 are shown in Table 1.
Table 1 also shows the comprehensive evaluation results considering battery characteristics other than the cycle life.
Comprehensive evaluation is very excellent when the cycle life is 4900 times or more and there is no problem in characteristics other than the life (◎), and the cycle life is 4900 times or more but excellent in battery characteristics slightly (○) The cycle life of less than 4900 times was evaluated as inferior (x).

As is clear from Table 1, the lead storage batteries of Examples 1 to 5 of the inventive examples had a cycle life of 4900 times or more and a long life. This is because sulfation was suppressed by the synergistic effect of Zn and Al.
The synergistic effect of Zn and Al is, for example, No. 1 in Example 1 (example of the present invention). 3 and Comparative Example 1 It is clear when 30,33 are compared.
In Examples 4 and 5, since the specific gravity of the electrolyte was less than 1.250 or exceeded 1.320, at least one of a decrease in battery capacity and a decrease in electrolyte was observed. However, both were practically acceptable.

  On the other hand, in the lead acid batteries of Comparative Examples 1 and 2, since the Zn or Al content was outside the specified value of the present invention, sulfation was not suppressed and the cycle life was reduced. Further, No. with a large amount of Zn. Nos. 32 and 37 show a decrease in hydrogen overvoltage and an increase in self-discharge. In 35 and 40, the internal resistance of the battery increased.

  When the lead storage battery (Examples 1-5) of this invention was mounted in the new system introduction vehicle, it was confirmed that a battery life is remarkably excellent compared with the conventional lead storage battery.

Claims (4)

  Zn is contained in the negative electrode plate in an amount of 0.005 to 0.1 parts by weight in terms of metal (parts by weight per 100 parts by weight of the negative electrode active material), and Al is contained in the electrolyte in an amount of 2 to 50 g / liter in terms of sulfate. Lead acid battery characterized by that.   A lead storage battery characterized in that the electrolyte contains 0.06 to 1.4 g / liter of Zn in terms of metal and 2 to 50 g / liter of Al in terms of sulfate.   Zn is contained in the negative electrode plate in an amount of 0.005 to 0.1 parts by weight in terms of metal (parts by weight per 100 parts by weight of the negative electrode active material), and the electrolytic solution contains Zn in an amount of 0.06 to 1.4 g / liter in terms of metal. A lead-acid battery characterized in that Al is contained in an amount of 2 to 50 g / liter in terms of sulfate.   The lead acid battery according to any one of claims 1 to 3, wherein the electrolytic solution is a sulfuric acid aqueous solution having a specific gravity at 20 ° C of 1.250 to 1.320.