JP2006339030A - Method of recovering lead battery by electrical treatment - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method of recovering performance by electrical treatment and securing a long term durability life without disassembling a lead battery deteriorated in performance due to effect of lead sulfate (PbSO4) crystal solid generated on the surface of the electrode. <P>SOLUTION: In this revival method, the pulse current and charging current are flowed simultaneously, and the pulse current value is made 0.1-2 A and the charging current value is made 2-10 A in which the positive electrode (PbO2) and the negative electrode (Pb) being an active material of the electrode plate are not damaged even if they are kept flowing for a long time, thereby a durability life expected can be achieved. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

The present invention relates to a method for recovering performance of a lead battery with degraded performance by electrical treatment.

Lead batteries mounted on automobiles, forklifts, etc. discharge to operate lights, move forklift claws and run. After use, it is charged by a generator installed in a car. However, a lead sulfate (PbSO4) crystal film is formed on the surfaces of the anode (PbO2) and the cathode (Pb) of the battery while repeating these discharges and charges. This has a non-conductive nature and degrades performance without reaching a sufficient voltage when charged. As a method of reviving a battery in such a state, a method of supplying a charging current for charging while supplying a pulse current is often employed (see, for example, Patent Document 1). The pulse current is for decomposing and removing the lead sulfate crystal film, and the lead sulfate crystal film covering the electrode surface is destroyed and removed by the impact force of the pulse current.

JP 2004-134139 A

In the above patent documents, examples of charging current values of 10 to 50 A, pulse current values of 9 to 40 A and the like are described, and many other proposals have been made regarding these values. Various conditions such as a charging current value, a waveform of a pulse current other than the pulse current value, and a charging / discharging process having an interval have been proposed. However, batteries that have been revived under these conditions are used for electric forklifts when they are new and are considerably shorter than about 5 years. (In addition, there may be situations where charging to the full level is not possible after use in automobiles.) When revived under the above conditions, the lead sulfate crystal film covering the electrode surface is completely removed. In some cases, a part of the electrode tends to remain, and the unevenness of the electrode surface becomes severe, and a part of the hole opens and breaks. Under such circumstances, extension of the service life of the battery, complete removal of the lead sulfate crystal film on the electrode surface, and reduction of damage on the electrode surface are extremely important technical goals.

In a method for recovering the performance of a lead battery in which lead sulfate (PbSO4) crystals are generated on the electrode plate surface and the performance is deteriorated, the lead sulfate crystal film is decomposed and removed with a current of 2 to 10 A as a charging current value. A resuscitation method by electrical treatment of a lead battery characterized by simultaneously using a pulse current value of 0.1 to 2A.

In the present invention, by selecting a new value that is significantly different from the charging current value and the pulse current value that have been applied conventionally, the useful life of the battery after resuscitation reaches a level comparable to that of a new battery and the electrode It was possible to completely remove the lead sulfate crystal film on the surface and prevent damage to the electrode surface.

In order to achieve the above technical goal, the inventor systematically researched various combinations of both charging current value and pulse current value in a very wide range including the values that have been implemented so far. The optimal combination of both was determined as described.

First, the pulse current value for performing the decomposition removal of the lead sulfate crystal film covering the electrode surface was examined in detail. The lead battery (for forklift, rated capacity 500Ah / 5h) with deteriorated performance was processed at 100 hours by changing the pulse current value from 0.05 to 20A with the charging current fixed at 5A. The result is shown in FIG. FIG. 1 shows the result of visual observation and evaluation of the state of decomposition and removal of the lead sulfate crystal film on the electrode surface and the degree of electrode breakage with respect to changes in the pulse current value.

It has been found that the lead sulfate crystal film is hardly removed when the pulse current value is less than 0.1 A, but the removal starts rapidly when the pulse current value exceeds 0.1 A, and the removal progresses greatly as the current value increases.

Further, the degree of electrode damage investigated at the same time hardly occurred when the pulse current value was 2 A or less, but when it exceeded this, the result increased rapidly.

Based on the above results, it was found that the pulse current value should be 0.1 A or more for decomposing and removing the lead sulfate crystal film, while it is 2 A or less for preventing electrode damage. A range of 0.1-2A was determined. In addition, Preferably it is 0.5-1.5A.

The above research is for a charging current value of 5 A, but the results were almost the same even when other current values were adopted.

From the above knowledge, it can be interpreted that the impact force generated at a pulse current value of 0.1 A or more exceeds the strength of the lead sulfate crystal coating itself or the adhesion between the coating and the electrode. On the other hand, with regard to electrode breakage, the lead sulfate crystal film covering the electrode surface is not necessarily uniform in thickness, and the film removal progresses quickly in the thin part. It is considered to be. When the pulse current value exceeds 2A, the impact force is estimated to exceed the strength of PbO2 or Pb that is an electrode material.

Next, the current value of charging, which is the role of charging for resuscitation, was examined in detail. For a battery with degraded performance (for forklifts, rated capacity 500Ah / 5h), change the charging current value from 1A to 50A by fixing the optimum pulse current value range of 1.0A obtained in Example 1, and resuscitation time For 500 to 10 hours. The result is shown in FIG.

  FIG. 2 shows the results of evaluating the service life after resuscitation with respect to changes in the charging current value. As the charging current decreased, the service life increased rapidly, and it was possible to realize 4.5 years, which is approximately 5 years, which is the service life of a new battery, at 10 A or less. When the charging current is less than 2A, the increase in the service life is saturated.

Based on the above findings, the charging current value is set to 10 A or less in order to secure 4.5 years, which is close to the useful life of a new battery, about 5 years. On the other hand, when it becomes less than 2 A, the increase in the service life is saturated and constant. The range of optimal charging current values was determined to be 2 to 10 A by inducing the resuscitation time to satisfy the charging of the standard current amount. In addition, Preferably it is 4-8A.

In addition, as a performance recovery process of the resuscitation method using the charging current and the pulse current of the present invention at the same time, a process for discharging the amount of electricity of the battery to a limited capacity (discharge end voltage), that is, a discharging process can be performed. Thereby, the decomposition removal of the lead sulfate crystal film produced | generated on the electrode surface is accelerated | stimulated more.

Electrode plate damage and lead sulfate crystal removal status for each pulse current value with a fixed charging current value of 5A. The service life of each charging current value with a fixed pulse current value of 1.0A.

Explanation of symbols

1... Lead sulfate crystal removal on the right scale of the graph.
2 .... Shows the electrode plate breakage on the left scale of the graph.

Claims (1)

In a method for recovering the performance of a lead battery in which lead sulfate (PbSO4) crystals are generated on the electrode plate surface and the performance is deteriorated, the lead sulfate crystal film is decomposed and removed with a current of 2 to 10 A as a charging current value. A resuscitation method by electrical treatment of a lead battery characterized by simultaneously using a pulse current value of 0.1 to 2A.

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