JPH11307134A - Charging method of alkaline aqueous solution secondary battery for backup - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging method of an alkaline aqueous solution secondary battery not affected by the variations in ambient temperature or the deterioration state of the battery. SOLUTION: This charging method of an alkaline aqueous solution secondary battery leaves the alkaline aqueous solution secondary battery for a backup until the voltage of the battery drops and reaches a predetermined voltage value V1 after it is fully charged, and the charging of the battery is resumed when its voltage reaches the predetermined voltage value V1. In this case, a pause period R1 is set every time a predetermined number (n) of pulses are counted and the charging by the repetition of pulse charging and pause is continuously performed until the voltage at the time of termination of the pause period R1 reaches a value not less than a predetermined voltage value V2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a backup alkaline aqueous solution secondary battery (various alkaline electrolyte secondary batteries for backup, installed in various devices for the purpose of operating when commercial power is stopped, and The battery pack)
The present invention relates to an improvement of a charging method of the present invention.

[0002]

2. Description of the Related Art In recent years, demands for batteries have been increasing due to miniaturization, high performance, and portableness of various electronic devices. In response, battery improvements and developments are becoming more active. Also, new application areas of batteries are expanding.

[0003] With the spread of batteries, there is an increasing demand for improved reliability of batteries mounted on various electronic devices.
In particular, conventional lead batteries and nickel cadmium batteries (hereinafter
Nickel-metal hydride batteries (hereinafter referred to as Ni / MH batteries) and lithium-ion batteries, which have significantly higher energy densities than those of Ni / Cd batteries, and the degree of damage due to accidents can be more serious, so reliability is high. Is an important issue.

[0004] One of the reliability factors is the extension of battery life. In particular, secondary batteries and battery packs (hereinafter collectively referred to as “batteries”) used for backup purposes during power outages are usually less likely to use batteries. When this occurs, there is a risk that the battery cannot be used and a serious situation may occur. In addition, if the battery life is short, frequent replacement is required, and labor and maintenance costs rise, which is not preferable.

[0005] The life of a secondary battery is attributable to a reduction in capacity due to a chemical deterioration of the battery constituent material with time or an electrochemical deterioration due to a charge / discharge cycle or the like.

Although it is hard to say that the cause of the chemical deterioration has been completely clarified, deterioration of the material of the separator and deterioration of the monomer of the starting material contained in the binder of the polymer compound constituting the electrode are not considered. It is considered the main factor. Also,
Lead, lead sulfate, nickel compound, hydrogen storage alloy,
Alternatively, it has been pointed out that the active material such as cadmium or the occlusion material of the active material is consumed or structurally changed.

In order to suppress chemical deterioration, it is necessary to remove impurities that can easily deteriorate from the constituent materials of the electrodes and the electrolyte,
The problem is dealt with by suppressing a chemical reaction of a side reaction that can occur with charge and discharge.

On the other hand, regarding the electrochemical deterioration, the change in density due to the structural change of the electrode active material due to charge and discharge in the cycle repeatedly causes the electrode to swell and shrink, resulting in mechanical deterioration, and the active material changed by discharge. May not be completely restored to the original structure or compound by charging, or may become overcharged or overdischarged due to improper upper limit of charge or lower limit voltage of discharge, and electrochemical decomposition of electrolyte etc. may occur as a side reaction. Is considered to be the main factor.

In order to suppress electrochemical deterioration, selection of a strong binder that can withstand expansion and contraction of the electrode, selection of an active material having a small change in density due to charge / discharge cycles and high reaction reversibility, and overcharge resistance This is addressed by adopting additives to improve the overdischarge resistance, optimizing the composition of the electrode and electrolyte materials, and optimizing the balance of the active materials of the positive and negative electrodes.

[0010] In a battery for backup use, most of the standby state is kept in a charged state, so that the degree of chemical deterioration and electrochemical deterioration due to overcharge mainly affect the battery life.
As the electrochemical deterioration due to overcharging, in an alkaline aqueous battery, a negative electrode active material (cadmium, hydrogen) due to a treatment reaction of oxygen generated at the end of charging is exemplified. With respect to electrochemical deterioration due to overcharge, a method of improving the overcharge resistance by mixing an additive into an electrode constituent material or performing appropriate metal plating is generally adopted.

However, even if these measures are taken, deterioration due to overvoltage at the end of charging is unavoidable due to the battery reaction mechanism. For this reason, various charging methods have been proposed, particularly with the aim of reducing deterioration due to overvoltage.

As a conventional charging method for an alkaline aqueous secondary battery for backup, a method of charging with a constant current value has been most commonly used. The most prevalent method is to disconnect the battery from the load.
There is known a trickle charging method in which charging is performed with a very small current of 1 CmA or less. The major feature of this method is that devices and parts related to charging are simple and inexpensive. However, the charging voltage of the battery greatly changes depending on the environmental temperature and the degree of deterioration, and the deterioration of the battery due to overcharging was extremely serious.

On the other hand, there has been proposed an intermittent charging method in which charging is performed for a certain period of time, then the battery is left to stand, and when the voltage drops to a certain voltage, charging is performed again. According to this charging method, once the battery is fully charged, the battery is left to a preset voltage, and when the voltage drops due to self-discharge or the like and reaches this set value, the battery is charged again with a constant current for a certain period of time. The capacity is maintained by repeating recharging. Alternatively, a method has been proposed in which recharging is not time, but a voltage at the end of charging is set, and between the two set voltage values, standing and recharging are repeated. Instead of setting the voltage, there is also a method of simply setting the time for leaving and recharging and repeating this with time.

However, in this method, although the chances of being exposed to overcharging are slightly improved as compared with the above-described method of simply continuing charging, the charging voltage also changes in this method depending on the environmental temperature and the state of deterioration of the battery. Problems were not solved, and fundamental electrochemical degradation could not be suppressed.

Apart from the above, there has also been proposed a method in which charging is not performed with a constant current but is performed by supplying a charging current as a pulse having a certain time width. In this method, the pause between the current pulses is smaller than the constant current value, so the chances of being exposed to overcharging are reduced as compared with charging with a constant current. However, the problem that the charging voltage changes depending on the state of deterioration cannot be solved, and fundamental electrochemical deterioration cannot be suppressed.

[0016]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method of charging an alkaline aqueous secondary battery for backup which is not affected by changes in environmental temperature or deterioration of the battery. Aim.

[0017]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides a backup alkaline aqueous solution secondary battery which is fully charged and then left until the battery voltage drops to and reaches a preset voltage value V1. This is a method for charging a backup alkaline aqueous solution secondary battery that recharges when the voltage value V1 is reached. A pause time R1 is provided for each predetermined number n of pulses to perform charging by repeating this pulse charging and pause. The operation is continuously performed until the voltage at the end of the pause time R1 becomes equal to or higher than the voltage value V2 set in advance.

The peak current value of the pulse charging is 0.1
It is not less than CmA and not more than 0.2 CmA.
The pause time R1 is a time that is not more than one time the total of the pulse charging time (including the pulse OFF time) performed during the previous pause time.

The average current value of the total charging time including the pause time R1 is not less than 0.033 CmA and not more than 0.1 CmA. When the voltage value V1 is 1.25 V
/ Cell or more and 1.3 V / cell or less, and the voltage value V2
Is not less than 1.3 V / cell and not more than 1.35 V / cell,
The voltage difference between the voltage values V1 and V2 is 0.5 V / cell or more.

[0020] The alkaline aqueous secondary battery for backup is a battery pack. The method for charging a backup alkaline aqueous solution secondary battery according to the present invention can suppress side reactions and overvoltage electrochemical degradation caused by charging by leaving a period of time for charging, and perform charging by two predetermined appropriate values. By performing the operation at a proper voltage value, the period during which the battery is exposed to overcharge is eliminated, and the capacity required for use is secured. In addition, there is a great advantage that charging by pulse can eliminate insufficient charging. In addition, the charging method according to the present invention basically does not need to change conditions according to changes in environmental temperature,
There is no need for a temperature monitor.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a diagram showing the concept of an embodiment of the present invention, and shows the change over time in battery voltage and current value during use.

In the charging method of the alkaline aqueous secondary battery for backup according to the present invention, the charging performed first after the battery is installed before reaching the state shown in FIG. 1 is a conventional charging method. Thus, the battery can be fully charged with a constant current, or can be fully charged by performing rapid charging with a large current of 1 CmA or more to a certain voltage before full charging, and then lowering the current value to continue charging.

In FIG. 1, the battery is fully charged, left to stand, and then charged again when the battery voltage reaches a preset voltage value V1. This charging is performed by repeating a current pulse of a peak current Ip for a certain number of times. Is a repetition,
A pause is provided after the pulse charging, and a method in which the pulse charging and the pause are repeated as one cycle is adopted. In the set of pulse charging and pause, the pulse width and pause time are adjusted in advance so that the difference between the charge start voltage Vs and the pause termination voltage Ve per cycle is repeated for a prescribed cycle. In the last cycle of the pulse charging and rest cycle repeated in this manner, the rest termination voltage Vee reaches the preset voltage V2, or
If this is exceeded, the charging is terminated and the battery is again left unattended until the voltage drops to a preset voltage V1.

In the method of charging an alkaline aqueous secondary battery for backup according to one embodiment of the present invention, the peak current value Ip of a pulse related to charging is set to 0.1 CmA or more and 0.2 CmA or more.
It is effective to make it CmA or less. If it is less than 0.1 CmA, the charge amount cannot correspond to the self-discharge rate particularly in a high-temperature environment, and there is a high possibility that charging failure will occur.
If the current value is larger than 2 CmA, the battery is overcharged, the battery is deteriorated, and the effect of the present invention is impaired.

In the method of charging an alkaline aqueous secondary battery for backup according to an embodiment of the present invention, the pause time R1 set for each predetermined number of charging pulses during the charging period is set between the previous pause and the pause. It is effective that the time is one time or less of the total pulse charging time (including the pulse OFF time). If the pause is longer than one time,
Particularly, in a high-temperature environment, the self-discharge amount exceeds the charge amount, which may result in poor charging, which is not preferable.

Further, in the charging method of the alkaline aqueous secondary battery for backup according to one embodiment of the present invention,
It is effective that the value obtained by dividing the amount of pulsed charging electricity by the total time of the pulsed charging and the pause time in each charging, that is, the average charging current value is 0.033 CmA or more and 0.1 CmA or less. When the average current value is less than 0.033 CmA, insufficient charging in a high-temperature environment becomes serious. On the other hand, when the average current value is greater than 0.1 CmA, overcharging tends to occur in a low-temperature environment, which is not preferable.

Further, in the method of charging the alkaline aqueous secondary battery for backup according to the embodiment of the present invention, the recharging by the current pulse having the pause is performed by changing the termination voltage of the pause from the preset voltage V1 separately. Until the set voltage V2 is reached or exceeded,
The set voltage value is such that V1 is 1.25 V / cell (in the case of series connection, the same applies hereinafter) or more and 1.3 V / cell or less, V2 is 1.3 V / cell or more and 1.35 V / cell or less, and It is effective that the difference between the two voltages V1 and V2 is 0.5 V / cell or more. When V1 is a voltage lower than 1.25 V / cell, the capacity when used is reduced by 10% or more, and there is a possibility that the use time which is specified in the device at the end of the battery life may not be satisfied. . Also,
If V1 is set to a voltage higher than 1.3 V / cell, there is almost no dwell time, and overcharge deterioration that is not much different from continuous charge may occur, which is not preferable. On the other hand, with respect to the value of V2, which is another set voltage, if V2 is lower than 1.3 V / cell, charging cannot be performed sufficiently and the capacity decreases, and if V2 is higher than 1.35 V / cell. Overcharge deterioration progresses to shorten the battery life, which is not preferable.

The voltage difference between the set voltages V1 and V2 is 0.5 V
If it is smaller than / cell, a so-called memory effect may be caused, and the output is lowered due to a decrease in discharge voltage, which is not preferable. More preferably, with respect to the method of charging the alkaline aqueous secondary battery for backup in one embodiment of the present invention, the pulse charging and the pause are defined as one charge cycle,
It is effective to adjust the difference between the charge start voltage and the pause termination voltage in the charge cycle so that this cycle is repeated five times or more. If the difference between the charge start voltage and the pause termination voltage is set so as to be at the end of the five cycles, the pause termination voltage Vee in the final cycle will end up greatly exceeding the preset voltage V2, and the overcharge deterioration may become serious. Is not preferred.

According to the method of charging an alkaline aqueous secondary battery for backup in one embodiment of the present invention, when the method is specifically used, the device power supply unit is configured as a charge control circuit having a configuration capable of satisfying the functions described above. Or a charging control circuit having a configuration capable of satisfying the above functions is housed in a battery pack together with a battery to be controlled.

FIG. 2 shows an example of a block concept of a charge control circuit satisfying the function of the charging method according to the present invention. In FIG. 2, reference numeral 1 denotes a charge control circuit showing the charging method of the present invention as a specific function, 2 denotes a battery to be subjected to charge control, and 3 denotes a charge in the present invention mounted on the charge control circuit 1. A charge control microcomputer for performing charge control based on the method, 4 is a microcomputer for controlling electric power supplied from terminals 10 and 11 from a commercial power supply or the apparatus main body side, and 5 is a charge control microcomputer 3 A thermistor 6 for detecting a temperature abnormality in the circuit, and sends a detection of an output abnormality by the charge control microcomputer 3 including the temperature abnormality to the main body via a terminal 7. . The charging control circuit 1 on which these components are mounted is connected to the battery 2 to be controlled by terminals 8 and 9.

FIG. 2 shows a concept of a charge control circuit for implementing the charging method of the present invention, but the present invention is not limited to this as long as the charging method of the present invention can be realized.

The backup alkaline aqueous secondary battery to be controlled by the charging method according to the present invention is a battery using an alkaline aqueous solution as an electrolytic solution.
A d battery and a Ni / MH battery are conceivable, but other batteries can also be controlled if the above conditions are met.

In the method of charging an alkaline aqueous secondary battery for backup according to the present invention, a device requiring particularly high reliability can be considered, and the charging method realizes a necessary use time and a long battery life. By doing so, the operation at the time of power failure is ensured. However, there is no problem in using the device in which the alkaline aqueous solution secondary battery is mounted as a backup battery, and the use time and the long life can be realized more than before.

[0034]

EXAMPLES The method of charging an alkaline aqueous secondary battery for backup in the present invention will be described below with reference to specific examples, but the present invention is not limited to these examples.

Example 1 In order to use an AA trickle Ni / Cd battery (nominal capacity 600 mAh) as a test battery, the first full charge was performed in advance at 0.2 CmA for 15 hours, and the battery was recharged after standing. Charge start voltage V1 is 1.25
V, the voltage V2 for determining the end of charging is set to 1.35 V, and the peak current value of the charging pulse is set to 0.2 Cm.
A, a pulse width of 1 sec, a pulse interval of 2 sec, a ratio of a pulse charging time to a rest time thereafter is set to 1/1, a rest time is set to 10 minutes, and a charging average current is 0.033 CmA.
A charge control circuit having a structure shown in FIG. 2 equipped with a charge control microcomputer for controlling charge so as to satisfy the following condition was prepared and used for the test.

The test battery was connected to the terminals 8 and 9 of the charge control circuit, and the terminals 10 and 11 on the power supply side were connected to a charging / discharging device to be used for measuring battery characteristics. Before connecting the test battery to the charge control circuit, a capacity confirmation test was performed to determine an initial capacity in advance. That is, the test battery was directly connected to a higher-order charging / discharging device, first charged for 15 hours at 25 ° C. and a charging current of 0.1 CmA (60 mA), and then charged at 1.0 V at 25 ° C. and a discharging current of 0.2 CmA.
The charge / discharge was repeated three cycles, and the discharge capacity at the third cycle, 652 mAh, was determined, and this was defined as the initial capacity.

Next, a charge control circuit for controlling according to the charging method of the present invention connected to a test battery is installed in a 55 ° C. constant temperature bath and connected to the charge / discharge device, and the charge current value of the charge / discharge device is measured. 120 mA (0.2 CmA), charging period 28
On the day, a trickle life test was performed with a discharge current value of 600 mA (1.0 CmA) and a cut-off voltage of 1.1 V.

For comparison, the same type of AA type trickle Ni
/ Cd battery was placed in a 55 ° C. constant temperature bath and connected directly to the charging / discharging device, and the charging current was 20 mA (0.033 Cm
A), charging period 28 days, discharge current value 600 mA (1.0
CmA) and a final voltage of 1.1 V, and a trickle charge test was performed.

FIG. 3 shows the results. FIG. 3 is a diagram showing a change in the discharge capacity of the test battery for each cycle. In FIG. 3, reference numeral 31 denotes a curve showing a change in the capacity of the test battery that has been controlled according to the charging method of the present invention, and reference numeral 32 represents a change in the capacity of the test battery that has been subjected to trickle charging by the conventional method as a comparative example. FIG.

As is apparent from the results shown in FIG. 3, the discharge capacity of the battery whose charging is controlled according to the charging method of the present invention is larger than the discharge capacity of the battery that has been trickle-charged by the conventional method in the same cycle. In addition, the capacity is less reduced in each cycle, and an excellent life expectancy can be expected.

Example 2 AA type trickle Ni / Cd battery (nominal capacity: 600 mAh) was selected as a test battery, and a capacity confirmation test was first performed under the same conditions and method as in Example 1 to obtain an initial capacity, 667 mAh. Was. Next, a charge control circuit of the concept shown in FIG. 2 equipped with a charge control microcomputer for performing the charge control of the test battery under the same conditions as shown in Example 1 according to the charging method of the present invention was prepared. A capacity test was performed in the same manner as in Example 1, except that the test battery was connected to a test battery, and the test battery and the control circuit were installed in thermostats at different temperatures.

Next, a charge control circuit for controlling according to the charging method of the present invention connected to a test battery is installed in a constant temperature bath set at different temperatures from -20 ° C. to 60 ° C., and the charge / discharge device is mounted on the charge / discharge device. After charging, the charging current value of the charging / discharging device was 120 mA (0.2 CmA) and charging was performed for a charging period of 28 days.
(0.2 CmA) and a temperature characteristic test for performing discharge at a final voltage of 1.0 V was performed.

For comparison, the same type of AA type trickle Ni
/ Cd batteries were placed in the same constant temperature bath set at each temperature and connected directly to the charging / discharging device, and the charging current was 20 m
A (0.033 CmA), after charging for 28 days, the discharge current value was 120 mA (0.2 C
mA), a temperature characteristic test was performed in which discharge was performed with the final voltage set to 1.0 V.

FIG. 4 shows the results. FIG. 4 is a diagram in which the discharge capacity after 28 days of charging is plotted against each temperature, in which 41 is a curve showing the discharge capacity after 28 days of charging by the charging method of the present invention, and 42 Is a curve showing the discharge capacity after 28 days of charging by conventional trickle charging as a comparative example.

As is apparent from FIG. 4, when charging is performed by the charging method of the present invention, the effect of the capacity decrease due to temperature is smaller than that of the conventional trickle charging method, and it is understood that the charging method is superior.

[Embodiment 3] First full charge is 0.2 Cm
A, which is performed in 15 hours, the recharge start voltage V1 after standing is set to 1.25 V, the voltage V2 for judging the charge end is set to 1.35 V, respectively, the pulse width is 1 sec, the pulse interval is 1 sec, and the pulse charge is performed. The ratio between the time and the rest time is set to 2/1, and the rest time is set to 10 minutes. A mounted charge control circuit having the structure shown in FIG. 2 was manufactured and used for the test.

As a test battery, single-type trickle Ni / Cd
A battery (nominal capacity: 1800 mAh) was selected, connected to a charge control circuit in the same manner as in Example 1, installed in a 55 ° C. constant temperature bath, and connected to a charge / discharge test apparatus.

The charging / discharging test apparatus has a charging current of 360 mA.
(0.2 CmA), charge period 28 days, discharge current 1800
The battery was charged and discharged at a set current of 1.0 mA (1.0 CmA) and a discharge end voltage of 1.1 V.

The results are shown in FIGS. FIG. 5 is a diagram showing a change in capacity of each test battery connected to a charge control circuit set to a different peak current value with a cycle.

In FIG. 5, reference numeral 51 denotes a peak current value of 0.05 CmA, and 52 denotes a peak current value of 0.1 CmA.
In addition, 53 is a curve showing the change in capacity of the test battery connected to the charge control circuit set to a peak current value of 0.2 CmA and 54 to a peak current value of 0.25 CmA.

FIG. 6 shows the relationship between the peak current value (CmA) and the peak current value.
It is a characteristic view which shows the nominal capacity ratio (%) of the cycle. FIG.
From FIG. 6 and FIG. 6, the peak current value is set to 0.1 CmA or more and 0.2
It was clarified that, when it was set to CmA or less, the capacity was small and excellent characteristics were exhibited as compared with the case of other conditions.

[Embodiment 4] First full charge is 0.2 Cm
A, 15 hours, the recharge start voltage V1 after standing is set to 1.25 V, the voltage V2 for judging the end of charge is set to 1.35 V, and the peak current value of the charge pulse is set to 0.2 CmA. , Pulse width 1 sec, pulse interval 1 s
ec, pulse charging time (including pulse OFF time)
Made several charge control microcomputers with different pause times so that the ratio between the pulse charge time and the rest time was different for the charge control microcomputer that sets the charge to 10 minutes. Then, a charge control circuit equipped with this was manufactured and subjected to a test.

As a test battery, single-type trickle Ni / Cd
A battery (nominal capacity: 1800 mAh) was selected, connected to a charge control circuit in the same manner as in Example 3, installed in a 55 ° C. constant temperature bath, connected to a charge / discharge test device, and tested in the same manner as in Example 3. .

The results are shown in FIG. 7 and FIG. FIG. 7 is a diagram illustrating a change in capacity of each test battery connected to the charge control circuit set at different pause times with the cycle.

In FIG. 7, reference numeral 61 denotes a pause time of 5 minutes, 62 denotes a pause time of 10 minutes, and 63 denotes a pause time of 1 minute.
It is a curve which showed the change of the capacity of the test battery connected to the charge control circuit set up at 5 minutes.

FIG. 8 is a characteristic diagram showing the nominal capacity ratio (%) at the fifth cycle with respect to the pause time (minutes). 7 and 8
From the ratio of the pulse charging time to the rest time
When set to 1 or less, preferably 1/2, this is set to 1 /
Compared to the case where the value is set to a value larger than 1, it is clear that the capacity decrease is small and excellent characteristics are exhibited.

[Embodiment 5] First full charge is 0.2 Cm
A, 15 hours, the recharge start voltage V1 after standing is set to 1.25 V, the voltage V2 for judging the end of charge is set to 1.35 V, and the peak current value of the charge pulse is set to 0.2 CmA. The pulse width and the pulse width of the microcomputer for controlling the charging by setting the ratio between the pulse charging time and the rest time to 2/1, and setting the rest time to 10 minutes,
Several charge control microcomputers with different pulse intervals and different average charge current values were fabricated.
A charge control circuit on which this was mounted was manufactured and subjected to a test.

An A-type Ni / MH battery (nominal capacity: 2300 mAh) was selected as a test battery, connected to a charge control circuit in the same manner as in Example 3, installed in a 45 ° C. constant temperature bath, and connected to a charge / discharge test apparatus. .

The charging / discharging test apparatus has a charging current of 460 mA.
(0.2 CmA), charge period 28 days, discharge current 2300
The battery was charged and discharged at a set current of 1.0 mA (1.0 CmA) and a discharge end voltage of 1.1 V.

The results are shown in FIGS. 9 and 10. FIG. 9 is a diagram showing a change in capacity of each test battery connected to a charge control circuit set to a different average current value with a cycle.

In FIG. 9, reference numeral 71 denotes a test battery connected to a charge control circuit having a charging pulse width (time) of 1 sec, an interval between pulses of 4 sec, and an average current value of 0.027 CmA (61.3 mA). Capacity change, 72
Sets the charging pulse width (time) to 1 sec, sets the interval between pulses to 3 sec, and sets the average current value to 0.033 CmA (7
6.7 mA), a change in the capacity of the test battery connected to the charge control circuit set to 6.7 mA, 73 indicates a charge pulse width (time) of 1 second.
c, the inter-pulse interval was 1 sec, the average current value was set to 0.067 CmA (154 mA), and the change in capacity of the test battery connected to the charge control circuit was 74. The charging pulse width (time) was set to 4 sec. It is a curve which showed the capacity change of the test battery connected to the charge control circuit which set the average current value to 0.107 CmA (245 mA) at intervals of 1 sec.

FIG. 10 is a characteristic diagram showing the fifth cycle nominal capacity ratio (%) with respect to the pulse width (sec) / pulse interval (sec). 9 and 10, when the average charging current value of the pulse charging is set to 0.033 CmA or more and 0.1 CmA or less, it is compared with the case where the average charging current value is set to be smaller than 0.033 CmA or set to a value larger than 0.1 CmA. As a result, it was found that the capacity was small and excellent characteristics were exhibited.

[Embodiment 6] First full charge is 0.2 Cm
A, which is performed in 15 hours, the voltage V2 for determining the end of recharging after standing is set to 1.35 V, the peak current value of the charging pulse is set to 0.2 CmA, and the charging pulse width (time) is set to 1 sec. The charge control microcomputer that controls the charge by setting the interval between the pulses to 1 sec, setting the ratio of the pulse charging time to the resting time to 2/1, and setting the resting time to 10 minutes. Several charge control microcomputers having different voltages V1 were produced, and charge control circuits equipped with the microcomputers were produced and subjected to tests.

A type Ni / MH battery (nominal capacity: 2300 mAh) was selected as a test battery, connected to a charge control circuit in the same manner as in Example 3, installed in a 45 ° C. constant temperature bath, and connected to a charge / discharge test apparatus. .

The charging / discharging test apparatus has a charging current of 460 mA.
(0.2 CmA), charge period 28 days, discharge current 2300
The battery was charged and discharged at a set current of 1.0 mA (1.0 CmA) and a discharge end voltage of 1.1 V.

The results are shown in FIG. 11 and FIG. FIG.
FIG. 4 is a diagram showing a change in capacity of each test battery connected to a charge control circuit set to a different recharge start voltage with a cycle.

In FIG. 11, reference numeral 81 denotes a change in the capacity of the test battery connected to the charge control circuit whose recharge start voltage is set to 1.2 V, and 82 denotes a charge control circuit whose recharge start voltage is set to 1.25 V Change of the test battery connected to
3 is a change in the capacity of the test battery connected to the charge control circuit whose recharge start voltage is set to 1.3 V, 84 is the capacity of the test battery connected to the charge control circuit whose recharge start voltage is set to 1.32 V It is a curve which showed a change.

FIG. 12 shows the relationship between the recharge starting voltage (V) and
It is a characteristic view which shows the nominal capacity ratio (%) of the cycle. FIG.
From FIG. 1 and FIG. 12, when the recharge start voltage is set to be 1.25 V or more and 1.3 V or less, the capacity decreases as compared with the case where the recharge start voltage is set lower than 1.25 V or higher than 1.3 V. It was clarified to show small and excellent characteristics. If it is set to a value lower than 1.25 V, the discharge starting voltage becomes extremely low, and the capacity often becomes small.
Frequent charging and resting in the voltage range smaller than V (self-discharge)
Are repeated, and a voltage drop which is regarded as a memory effect occurs, and the capacity drop is large.

[Embodiment 7] First full charge is 0.2 Cm
A, 15 hours, the recharge start voltage after standing is set to 1.25 V, the peak current value of the charge pulse is 0.2 CmA, the charge pulse width (time) is 1 sec,
The charge control microcomputer that controls the charging by setting the interval between the pulses to 1 sec, setting the ratio of the pulse charging time to the resting time to 2/1, and setting the resting time to 10 minutes, ends the recharging after the standing. Several charge control microcomputers were prepared in which the voltage V2 to be determined was set to a different value, and a charge control circuit equipped with the microcomputer was prepared and subjected to a test.

An AA Ni / MH battery (nominal capacity 1100 mAh) was selected as a test battery, connected to a charge control circuit in the same manner as in Example 3, installed in a thermostat at 0 ° C., and connected to a charge / discharge test apparatus. did.

The charging / discharging test apparatus has a charging current of 220 mA.
(0.2 CmA), charge period 28 days, discharge current 220 m
A (0.2 CmA) and the discharge end voltage were set to 1.0 V to perform charging and discharging.

The results are shown in FIGS. 13 and 14. FIG.
FIG. 3 is a diagram showing a change in capacity of each test battery connected to a charge control circuit in which a voltage V2 for determining recharge termination is set to a different value, according to a cycle.

In FIG. 13, reference numeral 91 denotes a change in the capacity of the test battery connected to the charge control circuit in which the voltage V2 is set to 1.28V, and reference numeral 92 denotes a connection to the charge control circuit in which the voltage V2 is set to 1.3V. The test battery capacity change, 93,
A change 94 in the capacity of the test battery connected to the charge control circuit in which the voltage V2 was set to 1.35 V, 94 indicates that the voltage V2 was 1.4.
5 is a curve showing a change in capacity of a test battery connected to a charge control circuit set to V.

FIG. 14 shows the voltage V2 (V) for recharge termination determination.
FIG. 9 is a characteristic diagram showing a nominal capacity ratio (%) at the fifth cycle with respect to FIG. From FIGS. 13 and 14, when the voltage V2 for judging the end of recharging is set to 1.3V or more and 1.35 or less, this is set to be lower than 1.3V or 1.35.
It was clarified that the capacity was small and the characteristics were excellent as compared with the case where the value was higher than V.

[0075]

As described above, when the backup secondary battery is charged and its capacity is maintained by using the charging method of the present invention, the influence of the environmental temperature is minimized and the deterioration of the battery is suppressed. And a very large contribution can be made in using a backup secondary battery.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing the concept of an embodiment of the present invention.

FIG. 2 is an explanatory diagram illustrating a configuration of a charge control circuit according to an embodiment of the present invention.

FIG. 3 is a characteristic diagram showing a nominal capacity ratio (%) with respect to the number of cycles in a test result in Example 1 of the present invention.

FIG. 4 is a characteristic diagram showing a relative capacity (%) with respect to a charging temperature (° C.) in a test result in Example 2 of the present invention.

FIG. 5 is a characteristic diagram showing a test result in Example 3 of the present invention and showing a nominal capacity ratio (%) to the number of cycles.

FIG. 6 is a characteristic diagram showing a test result in Example 3 of the present invention, showing a nominal capacity ratio (%) at the fifth cycle to a peak current value (CmA).

FIG. 7 is a characteristic diagram showing a test result in Example 4 of the present invention, showing a nominal capacity ratio (%) to the number of cycles.

FIG. 8 is a characteristic diagram showing a test result in Example 4 of the present invention, showing a nominal capacity ratio (%) at a fifth cycle with respect to a pause time (minutes).

FIG. 9 is a characteristic diagram showing a test result in Example 5 of the present invention, showing a nominal capacity ratio (%) with respect to the number of cycles.

FIG. 10 is a characteristic diagram showing a nominal capacity ratio (%) at a fifth cycle with respect to a pulse width (sec) / pulse interval (sec) in test results in Example 5 of the present invention.

FIG. 11 is a characteristic diagram showing a nominal capacity ratio (%) with respect to the number of cycles in test results in Example 6 of the present invention.

FIG. 12 is a characteristic diagram showing a nominal capacity ratio (%) at the seventh cycle with respect to a recharge starting voltage (V) in a test result in Example 6 of the present invention.

FIG. 13 is a characteristic diagram showing a nominal capacity ratio (%) with respect to the number of cycles in a test result in Example 7 of the present invention.

FIG. 14 is a characteristic diagram showing a nominal capacity ratio (%) at a fifth cycle with respect to a voltage V2 (V) for recharge termination determination in a test result in Example 7 of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Charge control circuit 2 Battery 3 Charge control microcomputer 4 Power supply microcomputer 5 Switch 6 Thermistor 7 Abnormal output detection terminal 8 Battery connection plus terminal 9 Battery connection minus terminal 10 Power supply plus terminal 11 Power supply minus terminal

Claims (6)

[Claims] 1. After fully charging an alkaline aqueous secondary battery for backup, leave it until the battery voltage drops to and reaches a preset voltage value V1, and when it reaches the voltage value V1, recharge the battery. A method of charging an alkaline aqueous solution secondary battery, wherein a pause R1 is provided for each predetermined number n of pulses, and charging by repeating this pulse charging and pause is performed by the pause R
The voltage at the end of step 1 is a predetermined voltage value V2
A method for charging a backup alkaline aqueous solution secondary battery, wherein the method is continuously performed until the above is reached. 2. The method according to claim 1, wherein a peak current value of the pulse charging is 0.1 C.
2. The method for charging a backup alkaline aqueous solution secondary battery according to claim 1, wherein the charge is not less than mA and not more than 0.2 CmA. 3. The pulse charging time (including the pulse OFF time) performed between the pause time R1 and the previous pause time.
2. The time is less than one time of the total.
A method for charging an alkaline aqueous solution secondary battery for backup as described in the above. 4. The method for charging an alkaline aqueous secondary battery for backup according to claim 1, wherein the average current value of the total charging time including the pause time R1 is not less than 0.033 CmA and not more than 0.1 CmA. . 5. A voltage value V1 is 1.25 V / cell or more and 1.3 V / cell or less, and a voltage value V2 is 1.3 V / cell.
2. The charging of the alkaline aqueous secondary battery for backup according to claim 1, wherein the voltage is not less than the cell and not more than 1.35 V / cell, and the voltage difference between the voltage values V1 and V2 is not less than 0.5 V / cell. Method. 6. The method for charging a backup alkaline aqueous secondary battery according to claim 1, wherein the backup alkaline aqueous secondary battery is a battery pack.