JP2000333381A - Storage battery charging method and charging device - Google Patents

Abstract

(57) [Problem] An object to be solved by the present invention is to provide a storage battery using a Pb-Sb-based alloy lattice having a property that a battery voltage gradually rises gradually by repeated charging and discharging. Another object of the present invention is to provide a charging method and a charging device capable of reliably detecting a switching voltage and enabling constant current charging in which the charging current is gradually reduced. SOLUTION: In order to solve the above problem, primary constant current charging is performed with a predetermined current value, and when the battery voltage reaches a switching voltage, primary constant current charging is continued for an extended time, and the extension is performed. After a lapse of time, the operation shifts to secondary constant current charging with a current value lower than the primary constant current charging. First
It is desirable that the extension time for continuing the next constant current charging be shorter as the battery temperature is higher, and that the second charging time for executing the second constant current charging be shorter as the battery temperature is higher.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging method and an apparatus for charging a storage battery, particularly a lead storage battery, while gradually reducing a charging current.

[0002]

2. Description of the Related Art Conventionally, as a method for charging a lead storage battery used for a cycle service such as an electric vehicle, a transportation vehicle, a golf cart, etc., a two-stage constant current charging which can be charged in a short time has been performed.

In this two-stage constant current charging, charging is performed with a large current until the storage battery voltage reaches a preset switching voltage, and at the moment when the switching voltage is reached, switching to small current charging is performed, and the charge amount is reduced. For example, the charging is continued for a predetermined time until it reaches 120%.

However, in this type of charging method, in order to shorten the charging time, it is necessary to make the primary charging period performed with a large current as long as possible. To this end, the switching voltage must be set high. become. However, if the switching voltage is set high, if the storage battery voltage does not reach the switching voltage even if the primary charging is continued, control becomes impossible and overcharging occurs. For this reason, the switching voltage must be set low in view of the margin, and the time for the primary charging is shortened. For this reason, the amount of electricity in the primary charging is reduced and the secondary charging makes up for it, so that the conventional charging method has a problem that the charging time cannot be sufficiently reduced.

[0005] In recent years, sealed lead-acid batteries that do not require water refilling have become widespread. In this sealed lead-acid battery, oxygen gas generated at the positive electrode during charging is converted into a charged active material (P) at the negative electrode.
The battery is hermetically sealed by a method called a negative electrode absorption type in which hydrogen gas generation from the negative electrode is suppressed by reacting with b) and absorbing oxygen gas. As a grid for the positive electrode of this sealed lead-acid battery, a Pb-Ca alloy grid is generally adopted. However, when the storage battery is used under extreme conditions such as high temperature and deep discharge, PbSO There is a drawback that an early capacity reduction (hereinafter referred to as PCL) phenomenon occurs in which the passive layer ₄ is formed and the capacity is reduced promptly, resulting in a short life. Since this PCL phenomenon is peculiar to a battery using a Pb-Ca alloy lattice for the positive electrode, it is also possible to use a Pb-Sb-based alloy lattice generally used in a liquid type battery also for the positive electrode of a sealed storage battery. Conceivable.

[0006] However, a storage battery using a Pb-Sb-based alloy lattice has a property that, when charging and discharging are repeated, the rise in battery voltage accompanying charging becomes gradually slower. For this reason, in the above-described charging method in which the switching voltage is detected and controlled, the battery voltage does not reach the set switching voltage even when the charging proceeds, so that control becomes impossible and overcharging is caused.
Electrolysis of water in the electrolyte occurs. However, the sealed lead-acid battery contains only a minimum amount of the electrolytic solution. Therefore, when water is consumed, the battery quickly runs out of water and becomes unusable. Because of this, Pb-S without PCL phenomenon
A sealed lead-acid battery using a b-based alloy grid as the grid for the positive electrode has not been put to practical use because of the bottleneck of the charging device.

[0007]

Therefore, the first aspect of the present invention
It is an object of the present invention to provide a charging method and a charging device that can shorten the charging time even when the switching voltage is set low when performing constant current charging by gradually lowering the charging current. Further, a second object of the present invention is to reliably detect a switching voltage even in a storage battery using a Pb-Sb-based alloy lattice, which has a property that the battery voltage gradually rises gradually by repeated charging and discharging. It is an object of the present invention to provide a charging method and a charging device that can perform constant current charging by lowering the charging current step by step.

[0008]

According to a first aspect of the present invention, there is provided a method for charging a storage battery, comprising: performing primary constant current charging at a predetermined current value; When the voltage is reached, the primary constant current charging is continued for a predetermined extension time, and after the predetermined extension time has elapsed, the secondary constant current charging with a current value lower than the primary constant current charging is performed. It is characterized by shifting.

Further, in the method of charging a storage battery according to the second aspect of the present invention, in the first aspect of the invention, the duration of the first constant current charging continued after the switching voltage is reached is set to Next, in the battery charging device according to the third aspect of the present invention, a constant current charging circuit for charging the storage battery with a predetermined current, and a battery voltage of the storage battery during charging. A voltage detection circuit, a timer means for measuring the time from when the battery voltage detected by the voltage detection circuit reaches a predetermined switching voltage and detecting that a predetermined extension time has been reached, In response to the operation, the constant current charging circuit performs primary constant current charging with a predetermined current value, and the timer operation is performed on condition that the battery voltage detected by the voltage detection circuit reaches a predetermined switching voltage. The first constant current charging is continued until the time measured by the stage reaches the extension time, and after the extension time has elapsed, the constant current charging circuit uses a lower current value than the first constant current charging. Charge control means for executing the second constant current charging.

Next, in a battery charging device according to a fourth aspect of the present invention, in the third aspect of the present invention, a temperature sensor for substantially detecting a battery temperature and a temperature detected by the temperature sensor are provided. An extension time setting means for setting the extension time to be shorter as the height is higher.

Next, in the battery charging device according to the fifth aspect of the present invention, in the third aspect of the present invention, the charging control means stops the time counting from the start of the second constant current charging. Time timer means, wherein the charging control means terminates the secondary constant current charging when the end time timer means has counted a predetermined secondary charging time.

Next, in the battery charging device according to the present invention, the temperature sensor for substantially detecting the battery temperature and the temperature detected by the temperature sensor are the same. Secondary charging time setting means for setting the secondary charging time to be shorter as the charging time is higher.

[0013] Next, according to a seventh aspect of the present invention, in the method for charging a storage battery according to the first or second aspect, the storage battery is a lead storage battery.

Next, in the battery charging device according to the present invention, the storage battery is a lead storage battery in the invention according to any one of the third, fourth, fifth, and sixth aspects.

Further, in the charging device for a sealed lead-acid battery using the Pb-Sb-based alloy grid as the grid for the positive electrode according to the ninth aspect of the present invention, a constant current charging circuit for charging with a predetermined current; A voltage detection circuit for detecting the battery voltage of the lead-acid battery, and measuring the time from when the battery voltage detected by the voltage detection circuit reaches a predetermined switching voltage to detect that a predetermined extension time has been reached. Timer means and a constant current charging circuit performs primary constant current charging with a predetermined current value in response to a charging start operation, and determines that the battery voltage detected by the voltage detection circuit has reached a predetermined switching voltage. The primary constant current charging is continued until the time measured by the timer means reaches the extension time in the condition,
And charging control means for causing the constant current charging circuit to execute secondary constant current charging with a lower current value than the primary constant current charging after the elapse of the extension time.

Next, the Pb-Sb according to the tenth aspect of the present invention will be described.
In a charging device for a sealed lead-acid battery using a system alloy grid as a grid for a positive electrode, in the invention according to claim 9, a temperature sensor for substantially detecting a battery temperature and a temperature detected by the temperature sensor are high. An extension time setting means for setting the extension time to be shorter.

Next, the Pb-Sb of the invention according to claim 11 is described.
In the charging device for a sealed lead-acid battery using a system alloy grid as the grid for the positive electrode, the charging control means according to the ninth aspect of the present invention, wherein the charging control means measures the time from the start of the secondary constant current charging. Time charging means, wherein the charging control means terminates the secondary constant current charging when the end time timer measures a predetermined secondary charging time.

The Pb-S of the invention described in claim 12
In a charging device for a sealed lead-acid battery using a b-based alloy grid as a grid for a positive electrode, the invention according to claim 11,
A temperature sensor for substantially detecting a battery temperature, and secondary charging time setting means for setting the secondary charging time longer as the temperature detected by the temperature sensor becomes higher.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below, but the present invention is not limited to the following description.

The method and the apparatus for charging a storage battery according to the present invention perform primary constant current charging at a predetermined current value, and when the battery voltage reaches a predetermined switching voltage, the primary constant current is charged for a predetermined extension time. The charging is continued, and after the elapse of the extended time, a second current value lower than the primary constant current charging is applied.
The feature is that it shifts to the next constant current charging.

The primary constant current charging raises the battery voltage, and after reaching a predetermined switching voltage, the primary constant current charging is continued for a predetermined extension time. Therefore,
Even if the switching voltage is set lower than in the prior art so that the voltage rise can be detected with certainty, instead of immediately switching to the second constant current charging having a low current value, the primary current having a large current value is not changed. After the constant-current charging is continued for the extended time, the mode shifts to the second constant-current charging, so that a larger amount of electricity can be charged, and the charging time can be shortened.

In this case, if the duration of the primary constant current charging, which is continued after the battery voltage reaches the switching voltage, is shortened as the battery temperature becomes higher, an appropriate charge amount is obtained and overcharging is prevented. it can.

[0023] Such a charging method and an apparatus employing the method are suitable for a lead-acid battery, particularly a sealed lead-acid battery using a Pb-Sb alloy lattice as a positive electrode lattice. The practical use of storage batteries has become possible. A storage battery using a Pb-Sb alloy grid as the grid for the positive electrode has a property that the battery voltage increases gradually with charging when charging and discharging are repeated.
According to the present invention, since the switching voltage can be set low, it is possible to reliably detect an increase in the battery voltage. This means that the primary constant current charging performed with a large current is surely completed and
This means that it is possible to shift to the next constant current charging, and that overcharging can be reliably prevented. The fact that there is no fear of overcharging means that even when used for charging a sealed lead-acid battery having an extremely low electrolyte content, no liquid dying occurs, and as a result, the Pb-Sb alloy lattice It becomes possible to commercialize and extend the service life of a sealed lead-acid battery using a lithium alloy as a grid for a positive electrode, and its utility is extremely high in severe applications such as electric vehicles.

[0024]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments.

First, 1.2% by weight of antimony-0.05% by weight of selenium-0.1% by weight of tin-0.2% by weight of arsenic
-A sealed lead-acid battery having a 3-hour rate capacity of 30 Ah was prepared in accordance with a conventional method using a positive electrode grid made of an alloy of the remainder of lead.

On the other hand, the configuration of the charging device is as shown in FIG. A constant current charging circuit 2 is connected to the lead-acid battery 1 manufactured as described above, and charges the lead-acid battery 1 with a constant current of a value instructed based on a signal from the CPU 3.
A voltage detection circuit 4 is also connected to the lead storage battery 1, and a signal corresponding to the detected battery voltage is given to the CPU 3.

A temperature sensor 5 attached to the lead storage battery 1 is connected to the CPU 3, and a signal corresponding to the temperature of the lead storage battery 1 is given to the CPU 3. The CPU 3 has an extended time timer circuit 6 and a secondary charge timer circuit 7.
Are connected, and each of the timer circuits 6 and 7 starts the time counting operation in response to the start signal Ss from the CPU 3, and the extended time timer circuit 6 sends the signal to the CPU 3 when the preset “extended time t _a ” is reached. The secondary charge timer circuit 7 outputs the time-up signal Su, and the secondary-charge timer circuit 7 outputs the time-up signal Su when the set “secondary charge time t ₂ ” has elapsed from the start.
Is output. The CPU 3 is equivalent to a charge control means, and gives a current command value to the constant current charging circuit 2 at a timing corresponding to the battery voltage by a required software configuration to perform primary constant current charging and secondary constant current charging. In addition to having a function of sequentially executing charging and charging, it also functions as an extended time setting unit and a secondary charging time setting unit for setting the “extended time t _a ” and the “secondary charging time t ₂ ”.

Now, the lead storage battery 1 is charged to 50% (15 A
h) After the discharge, as shown in FIG.
The secondary constant current charging and the secondary constant current charging with a charging current of 1.5 A were sequentially performed. Switching from the primary to the second Tsugijo current charging, the battery voltage from a switching voltage Vc = 2.35V / cell was performed where the extension time t _a has passed.

Particularly in this embodiment, the extended time t _a
Is calculated in CPU3 according to the following formula, as the temperature T is high, extra time t _a is defined to be shorter.

T _a = ab-ln (T + c) (1) In the first equation, a, b, and c are coefficients having positive values,
It is set in consideration of the rated capacity of the battery, the configuration of the battery, the operating conditions, the current value of the primary constant current charging, the predetermined voltage switching value, and the like. In this embodiment, a = 137 and b = 3
1, c = 8. The unit of the temperature T in the first equation Celsius, the unit of t _a is "minute". The “secondary charging time t ₂ ”, which is the time during which the secondary constant current charging is performed, is also calculated by the CPU 3 according to the following equation, and the temperature T ₂ is also calculated.
, The secondary charging time t ₂ is determined to be shorter.

T_Two= D−e · ln (T + f) (2) In the second equation, d, e, and f are coefficients having positive values,
Battery rated capacity, battery configuration, operating conditions, primary constant current
Charging current value, predetermined voltage switching value, secondary constant current charging
It is set in consideration of the current value, etc.
Then, d = 571, e = 91, and f = 8. In addition,
In the second equation, the unit of the temperature T is Celsius, t _TwoIs in minutes
It is. <Comparative Example> In a comparative example not implementing the present invention,
Indicates an extended time in the CPU 3 for comparison with the embodiment.
Invalidating the setting means and the secondary charging time setting means, and_a
= 24 minutes, t_Two= Fixed for 4 hours. <Examination of results> The charging in the examples and comparative examples was 5
C., 30 ° C., and 50 ° C., as shown in Table 1.
Results of charging amount and life cycle

[0032]

[Table 1]

As shown in the present invention. Point A on curve A
-1, A-2, and A-3 show changes in the amount of charge (rated capacity ratio%) for the examples at 5 ° C., 30 ° C., and 50 ° C., and the solid line in FIG. The points B-1, B-2, and B-3 on the curve B indicate the amount of charge at each temperature at the time when the first constant current charging is completed. Points C-1, C-2, and C-3 on the curve C indicate the amount of charge at each temperature at the time when the secondary constant current charging ends. Here, the curve A in the figure decreases to the left due to the property of the sealed lead-acid battery that the charging voltage value depends on the temperature. Accordingly, in the comparative example in which an extended time t _a and the secondary charging time t ₂ is constant, the charge amount at the time the first Tsugijo current charging is finished curve D shown by a chain line, the second Tsugijo current The charge amount at the time of completion of the charge is as shown by a curve E indicated by a two-dot chain line, and the charge amount tends to decrease at low temperatures. On the other hand, in the embodiment, the charge amount at the time of completion of the charge is as shown by the straight line C, and is constant regardless of the temperature.

This affects the cycle life. 5 ° C. by the charging method of the comparative example in which t _a and t ₂ were kept constant.
When the battery was charged, the life of the battery was exhausted due to accumulation of lead sulfate of the negative electrode active material due to insufficient charging. Also, when the battery at a temperature of 50 ° C. was charged by the charging method of the comparative example in which t _a and t ₂ were also kept constant, the electrode group was dry, and the loss of water due to an excessive charge amount was a cause. Battery life has expired. On the other hand, in the embodiment, the above phenomenon does not occur, and the cycle life is long. However, even with the charging method of the comparative example, as described above,
It can be used for cycle charging of a sealed lead-acid battery using a Pb-Sb-based alloy grid as a grid for the positive electrode. Sufficient performance can be exhibited unless it is used especially in cold regions or high-temperature conditions.

In order to detect the battery temperature, it is preferable to attach the temperature sensor 5 to the storage battery 1 as in the above embodiment, but when the charging device is configured as an external charging device separate from the storage battery, The ambient temperature may be detected, and the battery temperature may be estimated and calculated from the ambient temperature. In many cases, at least the battery temperature at the start of charging is substantially equal to the ambient temperature, so that the ambient temperature can be estimated substantially as the battery temperature at the start of charging. Also, although the battery temperature rises with the progress of charging, if the temperature at the start of charging is known, it is possible to empirically estimate what temperature rise curve will be drawn according to the charge amount. Can be calculated and determined with a certain degree of accuracy from the atmospheric temperature at the start of charging.

Further, in the above-described embodiment, an example of the charging device for charging a sealed lead-acid battery using a Pb-Sb-based alloy grating as a positive electrode grating has been described. Also, the present invention can be applied to a lead-acid battery using a Pb-Ca-based alloy lattice as a positive electrode lattice. In the case of a lead-acid battery using a Pb-Ca-based alloy grid as the grid for the positive electrode, the secondary constant current charging can be terminated by detecting that the battery voltage has reached a predetermined voltage.

In the above-described embodiment, the two-stage constant current charging in which charging is performed with two types of current values is performed. However, the present invention is not limited to this, and charging is performed with three types of current values that are gradually reduced. The present invention can also be applied to three-stage constant current charging. In this case, the tertiary constant current charging with a smaller current value may be performed after the completion of the secondary constant current charging in the above embodiment. Further, in the above-described embodiment, a so-called hardware timer is configured by using the extended time timer circuit 6 and the secondary charge timer circuit 7, but the present invention is not limited to this, and the software of the CPU 3 is used to implement the timer. A timer may be configured.

Further, in the above embodiment, the example of the lead storage battery is described. However, as long as the storage battery is other than the lead storage battery, the effects of the present invention can be obtained.

[0039]

As described above, the present invention provides a storage battery,
In particular, for sealed lead-acid batteries that use a Pb-Sb-based alloy grid as the grid for the positive electrode, appropriate charging is possible over a wide range of temperature conditions, and a longer battery life can be achieved. Its practical value is extremely large in cycle service applications such as golf carts.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a charging device of the present invention.

FIG. 2 is a diagram showing transition of current and voltage during charging in the present invention.

FIG. 3 is a diagram showing a change in a charge amount during charging in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Storage battery 2 Constant current charging circuit 3 CPU 4 Voltage detection circuit 5 Temperature sensor 6 Extended time timer circuit 7 Secondary charging timer circuit

Claims (12)

[Claims] 1. A first constant current charging with a predetermined current value is performed, and when the battery voltage reaches a predetermined switching voltage, the first constant current charging is continued for a predetermined extension time, and the predetermined constant current charging is performed. A method for charging a storage battery, wherein after a lapse of time, a transition is made to a secondary constant current charging with a current value lower than the primary constant current charging. 2. The method according to claim 1, further comprising the step of:
2. The method of charging a storage battery according to claim 1, wherein the duration of the next constant current charging is shortened as the battery temperature increases. 3. A constant current charging circuit for charging a storage battery with a predetermined current, a voltage detection circuit for detecting a battery voltage of the storage battery being charged, and a predetermined switching of the battery voltage detected by the voltage detection circuit. Timer means for measuring the time from when the voltage has been reached and detecting that a predetermined extended time has been reached; and performing the first constant current charging with a predetermined current value by the constant current charging circuit in response to a charging start operation. Performing the primary constant current charging until the time measured by the timer means reaches the extension time on condition that the battery voltage detected by the voltage detection circuit has reached a predetermined switching voltage; Charge control means for causing the constant current charging circuit to execute a second constant current charge with a lower current value than the first constant current charge after the elapse of the extension time. The charging device of the storage battery. 4. An apparatus according to claim 3, further comprising: a temperature sensor for substantially detecting a battery temperature; and an extension time setting means for shortening said extension time as the temperature detected by said temperature sensor increases. A charging device for a storage battery according to claim 1. 5. An end time timer means for measuring a time period after the charge control means starts secondary constant current charging, wherein the charge control means is configured so that the end time timer means has a predetermined secondary charge. 4. The battery charging device according to claim 3, wherein the secondary constant current charging is terminated when the charging time is measured. 6. A temperature sensor for substantially detecting a battery temperature, and secondary charging time setting means for setting the secondary charging time shorter as the temperature detected by the temperature sensor becomes higher. The storage battery charging device according to claim 5, wherein 7. The method for charging a storage battery according to claim 1, wherein the storage battery is a lead storage battery. 8. The charging device for a storage battery according to claim 3, wherein the storage battery is a lead storage battery. 9. A constant current charging circuit for charging with a predetermined current, a voltage detection circuit for detecting a battery voltage of a lead-acid battery being charged, and a battery voltage detected by the voltage detection circuit is set to a predetermined switching voltage. Timer means for measuring the time from the arrival and detecting that the predetermined extension time has been reached, and performing the first constant current charging with a predetermined current value by the constant current charging circuit in response to a charging start operation, The first constant current charging is continued until the time measured by the timer means reaches the extension time on condition that the battery voltage detected by the voltage detection circuit has reached a predetermined switching voltage. A Pb-Sb system comprising: charge control means for causing the constant current charging circuit to execute secondary constant current charging with a current value lower than the primary constant current charging after a lapse of time. A charging device for charging sealed lead-acid batteries using an alloy grid as the grid for the positive electrode. 10. A temperature sensor for substantially detecting a battery temperature, and an extension time setting means for setting the extension time to be shorter as the temperature detected by the temperature sensor becomes higher. A charging device for charging a sealed lead-acid battery using the Pb-Sb-based alloy grid as described above as a grid for a positive electrode. 11. An end time timer means for measuring a time from the start of said second constant current charging by said charge control means, said charge control means comprising: The charging device for charging a sealed lead-acid battery using a Pb-Sb-based alloy grid as a grid for a positive electrode according to claim 9, wherein the secondary constant current charging is terminated when a charging time is measured. 12. A temperature sensor for substantially detecting a battery temperature, and secondary charging time setting means for setting the secondary charging time longer as the temperature detected by the temperature sensor becomes higher. The Pb-Sb according to claim 11, characterized in that:
Charger for charging sealed lead-acid batteries using a system alloy grid as the grid for the positive electrode.