JPH09115554A - Residual service life estimating method of negative electrode absorbing type sealed lead-acid battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily and accurately estimate its residual service life in a short time by judging a degraded condition of a storage battery from a discharge voltage variation in the storage battery and a voltage variation found from the product of internal resistance and an electric current. SOLUTION: First, internal resistance of a storage battery is detected, and next, the storage battery is discharged for a short time with a prescribed current intensity. At this time, a variation from pre-discharge voltage of discharge voltage when a prescribed time passes after discharge is started and a voltage variation by subtracting a voltage drop quantity by internal resistance from this variation are found, and the degradation of the storage battery is judged from a value of this voltage variation. The residual service life of the storage battery is estimated from the correlation (in J3 , a voltage variation is less than a judging point, and in J2 , a voltage variation is not less than a judging point) between previously found internal resistance and the residual service life of the storage battery in this degraded condition. Therefore, detection of a degraded condition of the storage battery and estimation of the residual service life can be accurately and easily performed in a short time.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a cathode absorption type sealed lead acid battery, which is discharged at a predetermined current for a short time,
The present invention relates to a method for estimating the remaining life of a cathode absorption sealed lead-acid battery.

[0002]

2. Description of the Related Art Conventionally, as a method for estimating the remaining life of a cathode absorption sealed lead-acid battery, a method of carrying out a capacity test has been generally used. This is a disadvantage that it takes a long time because the lead storage battery is once discharged and then returned to the charged state. Therefore, as a method of solving this drawback and simply detecting the deterioration state in a short time, a method of detecting the remaining capacity from the correlation between the internal resistance of the lead storage battery and the battery capacity has been proposed.

This method takes advantage of the fact that the internal resistance of a lead storage battery correlates with the battery capacity. The internal resistance of the cathode absorption sealed lead-acid battery increases as the deterioration progresses, and the time until the discharge voltage droops to reach the final voltage is shortened, and the battery capacity decreases.

[0004]

However, in these methods, first, the remaining capacity is detected, and then the remaining life is estimated from the relationship between the capacity and the usage period, and the capacity during the usage period becomes the end of life. If the lead battery is at the end of its life, it will not be known that the remaining life will be short. However, since the same one is always used regardless of the deterioration state, there is a problem that the remaining life cannot be accurately estimated.

[0005]

The present invention has been made under the background described above, and discharges a discharge voltage when a predetermined time has elapsed after the start of discharge when a storage battery is discharged at a predetermined current. From the change amount from the previous voltage and the value of the voltage change amount of the difference between the internal resistance and the product of the predetermined current, determine the deterioration state of the storage battery, and in this deterioration state, from the relationship between the internal resistance of the storage battery and the remaining life. By estimating the remaining life of the storage battery, the above-mentioned problems can be solved, and the accurate detection of the deterioration state and estimation of the remaining life of the cathode absorption sealed lead-acid storage battery can be performed easily in a short time. Another object of the present invention is to provide a method for estimating the remaining life of a cathode absorption type sealed lead-acid battery.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the method for estimating the remaining life of a cathode absorption type sealed lead-acid battery of the present invention, the change amount of the discharge voltage from the pre-discharge voltage at a predetermined time after the start of discharge, the internal resistance and the predetermined current The difference with the product, that is, the value of the amount of voltage change obtained by subtracting the voltage drop due to internal resistance from the amount of change from the voltage before discharge, indicates the ease of diffusion of the electrolytic solution in this cathode absorption sealed lead-acid battery. However, when the electrolytic solution cannot be easily diffused into the active material that is a porous body, such as when the electrolytic solution is reduced or the pressing force of the element group is poor, it becomes significantly large. This difference in the ease of diffusion becomes more apparent when the constant current discharge is performed, due to the difference in the drooping degree of the discharge voltage at the end of discharge.
If the diffusion cannot be performed easily, the drooping degree of the discharge voltage becomes larger, the time until the final voltage is reached becomes shorter, and the battery capacity decreases.

When the positive electrode plate is corroded due to overcharge, the internal resistance increases with the progress of deterioration due to a decrease in the electrical conductivity due to the thinning and breakage of the grid as the current collector, but due to the decrease in the electrolytic solution. It also increases when the contact area between the electrode plate filled with the active material and the separator holding the electrolytic solution is reduced. It is known that there is a correlation between the increase in the internal resistance and the remaining life. In the former case, the component that causes the life is the positive electrode plate, and in the latter case, the electrolytic solution. In general, the storage battery in which the deterioration as in the latter case is recognized is more bad in the usage environment than the former case, and the remaining life is more likely to be shorter than that estimated from the expected life.

From the above, in the method for estimating the remaining life of the cathode absorption type seal lead acid battery according to the present invention, the deterioration state of the cathode absorption type seal lead acid battery is previously determined from the ease of diffusion of the electrolyte solution. Is it due to the decrease of
It is more accurate because the correlation between the internal resistance and the remaining life is determined by determining whether it is caused by the corrosion of the positive electrode plate and not by using the same correlation. The remaining life can be estimated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows an example of discharge voltage characteristics when a cathode absorption type sealed lead-acid battery is discharged at a constant current. In FIG. 1, 1 is the discharge characteristic of a new cathode absorption type sealed lead acid battery, and 2 is the discharge characteristic of a cathode absorption type sealed lead acid battery that has deteriorated due to a decrease in the electrolyte. Further, 3 is the discharge characteristic of the cathode absorption type seal lead acid battery in which the positive electrode plate is corroded and deteriorated. The discharge characteristic 2 is different from the discharge characteristic 3 in that due to the decrease in the electrolytic solution, the diffusion of the sulfate ions in the electrolytic solution into the active material cannot be easily performed, and thus the drooping degree of the discharge voltage at the final stage of the discharge becomes larger. Therefore, the time required to reach the final voltage is shortened, and the battery capacity is further reduced.

FIG. 2 shows the cathode absorption type sealed lead-acid battery (1, 2, 3) shown in FIG. 1 at a predetermined current (I = 0.15C).
It is an example of the amount of change in the discharge voltage from the pre-discharge voltage when a predetermined time has elapsed (T = 5 sec) after the start of discharge when the discharge is performed for a short time in A). Here, the cathode absorption type sealed lead-acid battery is in a fully charged state in any deteriorated state. R ₁ is the internal resistance of a new cathode absorption type sealed lead acid battery, and R ₂ is the internal resistance of the cathode absorption type sealed lead acid battery that has deteriorated due to a decrease in the electrolytic solution. Internal resistance R ₂
Is larger than the internal resistance R ₁ because the contact area between the electrode plate filled with the active material and the separator holding the electrolytic solution is reduced. Further, R ₃ is an internal resistance of the cathode absorption type seal lead acid battery in which the positive electrode plate is corroded and deteriorated. In this example, the internal resistance R ₃ increased by the thinning and breakage of the current collector grid is larger than the internal resistance R ₂ .

In FIG. 2, Δ (IR ₁ ) is the product of the predetermined current I and the internal resistance R ₁ , and is the voltage change amount,
V ₁ is a change amount Δ (I of the discharge voltage after the start of discharge at the time T of the new cathode absorption type sealed lead-acid battery.
R ₁ ) The amount of change in voltage after the change. Also, Δ (I
R ₂ ) is the product of the predetermined current I and the internal resistance R ₂ , and is the amount of voltage change, and ΔV ₂ is the discharge at the time T of the cathodic absorption sealed lead-acid battery in which the electrolyte solution has deteriorated and deteriorated. It is the voltage change amount after the discharge voltage changes by the voltage change amount Δ (IR ₂ ) after the start. Further, Δ (IR ₃ ) is the product of the predetermined current I and the internal resistance R ₃ , and is the voltage change amount,
ΔV ₃ is the voltage change amount after the discharge voltage changes by the voltage change amount Δ (IR ₃ ) after the start of discharge at the time T of the cathode absorption type seal lead acid battery in which the positive electrode plate is corroded and deteriorated.

The voltage change amount ΔV ₃ is almost the same as the voltage change amount ΔV _1, and the sulfate ions in the electrolytic solution are easily diffused into the active material. The drooping degree is almost the same as the discharge characteristic 1. However, the amount of voltage change ΔV ₂
Is due to the fact that due to the decrease of the electrolyte solution, the diffusion of sulfate ions in the electrolyte solution into the active material is not easily performed,
It is larger than the voltage change amount ΔV ₁ .

FIG. 3 shows the liquid reduction rate of the separator and the voltage change amount Δ.
It is a figure showing the relation of V, and is a figure for explaining the judgment means of the deterioration state of the cathode absorption type seal lead acid battery. In FIG. 3, ΔV is the product of the internal resistance and the predetermined current I and the amount of change in the discharge voltage from the pre-discharge voltage at time T when the cathode absorption sealed lead-acid battery is discharged at the predetermined current I. The difference is the amount of voltage change. Here, the liquid reduction rate of the separator is expressed by the ratio of the reduced liquid amount to the electrolytic solution holding amount of the separator of the new cathode absorption type sealed lead acid battery. When the liquid reduction rate of the separator exceeds about 10 vol%, the electrolytic solution cannot be easily diffused and the voltage change amount ΔV becomes large. A point where the liquid reduction rate of the separator exceeds 10 vol% is set as a determination point, and the voltage change amount ΔV at that time is set to 40 mV.

When the voltage change amount ΔV is 40 mV or more, the electrolytic solution cannot be easily diffused due to the decrease of the electrolytic solution. When the amount of voltage change ΔV is less than 40 mV, the electrolyte is easily diffused. If such an increase in internal resistance is observed in such a cathode absorption type sealed lead storage battery, this cathode absorption type Lead acid batteries have deteriorated due to corrosion of the positive electrode plate.

FIG. 4 shows an example of the correlation between the internal resistance and the battery capacity of the cathode absorption type sealed lead-acid battery in which the diffusion of the electrolytic solution is easy and the case where it is not.
In FIG. 4, K ₃ is a correlation between the internal resistance and the battery capacity when the voltage change amount ΔV is less than the determination point, and K ₂ is when the voltage change amount ΔV is not less than the determination point. Is the correlation between the internal resistance and the battery capacity. The correlation K ₂ has a greater rate of decrease in battery capacity than the correlation K ₃ because the drooping degree of the discharge voltage at the end of discharge is larger. Here, the battery capacity is expressed as a ratio with the rated capacity as 100, and the internal resistance is expressed as a ratio with the initial value as 100.

FIG. 5 shows an example of the use period of the cathode absorption type sealed lead-acid battery shown in FIG. 1 and changes in battery capacity and internal resistance. In FIG. 5, Y ₂ shows the capacity transition of the cathode absorption type sealed lead-acid battery which deteriorated due to the decrease of the electrolytic solution, and Z ₂ shows the internal resistance transition of this cathode absorption type sealed lead-acid battery. is there. Y ₃ shows the capacity transition of the cathode absorption type sealed lead acid battery in which the positive electrode plate has corroded and deteriorated, and Z ₃ shows the internal resistance transition of this cathode absorption type sealed lead acid battery. Conventionally, the deterioration state has been determined by comparing the battery capacity obtained from the capacity test or the correlation K ₂ or K ₃ with the capacity transition Y ₂ or Y ₃ .

In FIG. 5, A is a point in the initial stage of deterioration. At time point A, almost no deterioration has occurred yet. Further, B is at the time of the middle stage of deterioration, and at time B, the decrease of the battery capacity is not yet recognized, but the deterioration surely progresses according to the usage period. However, in the conventional deterioration determination method, the deterioration state of the cathode absorption type sealed lead-acid battery is determined by measuring or estimating the battery capacity, although the remaining life is obviously different at the time points A and B.
The cathode absorption type seal lead acid battery of the time point B in which almost no decrease in battery capacity was observed was often regarded as the same deteriorated state as the cathode absorption type seal lead acid battery of the time point A.

Further, in FIG. 5, b ₂ shows the period from when the decrease in the battery capacity of the cathode absorption type lead-acid storage battery, which is deteriorated due to the decrease in the electrolyte solution, to the end of its life. The component that contributes to life is the electrolyte. b ₃ indicates the period from the time when the decrease in the battery capacity of the cathode absorption type seal lead acid battery in which the positive electrode plate is corroded and deteriorated is recognized to the end of its life. In this case, the component that contributes to the life is the positive plate.

From a technical point of view, it is difficult not to make the positive electrode plate a life factor, but the electrolyte is usually designed so as not to become a life factor in a normal use environment. Therefore, when the electrolyte is a factor of life and the cathode absorption type lead-acid battery reaches the end of its life, it is being used in an extremely hot and dry place, or it is being charged at a charging voltage much higher than the proper charging voltage. It was often used in an environment that promotes deterioration of the cathode absorption type sealed lead acid battery, and for this reason, the period b ₂ is shorter than the period b ₃ and the cathode absorption type sealed lead acid battery The remaining life is shortened.

FIG. 6 shows an example of the correlation between the internal resistance and the remaining life of the cathode absorption type sealed lead-acid battery, in which the positive electrode plate is the life factor and the electrolyte is the life factor. It is a thing. In FIG. 6, J ₃ is a correlation between the internal resistance and the remaining life when the voltage change amount ΔV is less than the determination point and the corrosion of the positive electrode plate is a life factor,
J ₂ is the correlation between the internal resistance and the remaining life when the voltage change amount ΔV is equal to or higher than the determination point and the decrease of the electrolyte is a life factor.

As described above, if the correlation between the internal resistance and the remaining life is utilized depending on the deteriorated component, the remaining life can be predicted with higher accuracy. Further, if the residual life is estimated from the increase rate of the internal resistance by using the correlation J ₂ or J ₃ , the internal resistance increases due to the increase of the internal resistance even in the case of the cathode absorption type sealed lead acid battery at the time point B in FIG. Since the state in the middle stage of deterioration is detected, it is possible to solve the problem that is confused with the deterioration state at time A as in the conventional deterioration determination method.

[0023]

As described above, according to the method for detecting the deterioration state of the cathode absorption type sealed lead acid battery according to the present invention, when the cathode absorption type sealed lead acid battery is discharged at a predetermined current,
Deterioration state determined in advance by determining the deterioration state from the difference between the change amount of the discharge voltage from the pre-discharge voltage after the lapse of a predetermined time after the start of discharge and the product of the internal resistance and the predetermined current, and obtained by the detection means. Since the remaining life is estimated from the relationship between the internal resistance and the remaining life, the remaining life will not be known until the end of the life, and it is not possible to prepare a replacement battery or due to different life factors. It is possible to solve the problem that the estimation cannot be performed accurately, and to accurately and accurately detect the deterioration state and estimate the remaining life of the cathode absorption type sealed lead acid battery in a short time. Therefore, its industrial value is extremely large.

[Brief description of the drawings]

FIG. 1 is a diagram comparing discharge voltage characteristics when a cathode absorption type sealed lead acid battery is discharged at constant current.

FIG. 2 is a diagram comparing the amount of change in the discharge voltage from the pre-discharge voltage after a lapse of a predetermined time after the start of discharge when the cathode absorption sealed lead-acid battery shown in FIG. 1 is discharged at a predetermined current for a short time.

FIG. 3 is a diagram showing a relationship between a liquid reduction amount of a separator and a voltage change amount ΔV.

FIG. 4 is a diagram comparing the correlation between internal resistance and battery capacity.

[FIG. 5] A diagram comparing changes in battery capacity and internal resistance with a period of use.

FIG. 6 is a diagram comparing the correlation between internal resistance and remaining life.

Claims (1)

[Claims] 1. First, the internal resistance of the storage battery is detected, and then
When the storage battery is discharged at a predetermined current for a short time, the amount of change in the discharge voltage from the pre-discharge voltage at a predetermined time after the start of discharge, and the amount of voltage change of the difference between the internal resistance and the product of the predetermined current. Then, the deterioration state of the storage battery is determined from the value of the voltage change amount, and the remaining life of the storage battery is estimated from the correlation between the internal resistance and the remaining life of the storage battery, which are obtained in advance in the deterioration state. Method of estimating the remaining life of a cathode absorption sealed lead-acid battery characterized by.