JP3303857B2 - Charging method for sealed nickel-metal hydride battery - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging system for a sealed nickel-metal hydride battery, and more particularly to a charging system suitable for rapid charging of a plurality of batteries having a stacked electrode group and trickle charging.

[0002]

2. Description of the Related Art In recent years, sealed nickel-metal hydride storage batteries have been in the spotlight because of their high capacity and elimination of Cd. However, a charging method equivalent to a sealed nickel-cadmium storage battery is often used as a charging method for the sealed nickel-metal hydride storage battery. This is because the charging voltage behaviors of the sealed nickel-metal hydride storage battery and the sealed alkaline storage battery are similar. However, there are two major differences in the charging characteristics of these batteries. First, the first different point will be described below. In the case of a sealed nickel cadmium storage battery, the battery internal pressure increases during overcharge. This is mainly due to oxygen generated from the positive electrode during overcharge. Oxygen is absorbed by the negative electrode and the increase in battery internal pressure is suppressed, but this reaction is accelerated as the battery temperature increases. Therefore, in the sealed nickel cadmium storage battery, when overcharged, the battery internal pressure decreases as the battery temperature increases. On the other hand, in a sealed nickel-metal hydride storage battery, the battery internal pressure increases at a low temperature for the same reason, but even at a high temperature, the hydrogen dissociation equilibrium pressure of the hydrogen storage alloy used for the negative electrode increases and the battery internal pressure increases.

A second difference is that when trickle charging is performed at a low temperature for a long time, the Cd electrode does not change but the hydrogen storage electrode is inactivated. Therefore, when trickle charging is performed in the same manner as in the sealed nickel-cadmium storage battery, the sealed nickel-metal hydride storage battery cannot be discharged.

[0004]

When the same charging method is applied due to the difference in behavior at the time of charging as described above, the following problems 1 to 4 occur.

The first problem is that in a sealed nickel-metal hydride storage battery using a hydrogen storage alloy for the negative electrode, the hydrogen storage equilibrium pressure of the alloy increases at high temperatures. Therefore, at the time of overcharging in rapid charging, the battery internal pressure increases as the battery temperature increases. Therefore, if the same charging method as that of a sealed nickel cadmium storage battery in which the battery internal pressure decreases as the temperature increases during overcharging is used, the battery internal pressure increases, and the closed system is broken, resulting in a problem of shortening the service life. For example, there is a method of charging a sealed nickel cadmium storage battery that detects a rising speed of a battery temperature and attenuates a charging current. As a feature, a constant amount of charged electricity is obtained from a low temperature to a high temperature. Therefore, when used in a sealed nickel-metal hydride battery, the internal pressure increases at high temperatures.
As other methods, a charging method using a difference between the ambient temperature and the battery temperature, detection of a maximum value of a charging voltage (hereinafter referred to as "V peak detection"), and reduction of a charging voltage (hereinafter referred to as "minus delta V detection"). There are similar results. On the other hand, there is a battery temperature detector, but it works as a safety device when charging control does not work well.
The purpose is to prevent the battery components from being thermally degraded due to abnormal temperature rise of the battery. Therefore, many of them operate at 60 ° C. to 80 ° C., and control accuracy is insufficient because a thermal fuse or a bimetal method is used for the detector. As described above, when the conventional charging method of the sealed nickel-cadmium storage battery is used for the sealed nickel-metal hydride storage battery, the internal pressure of the sealed nickel cadmium storage battery cannot be sufficiently prevented from increasing due to a rise in temperature. The above is the first problem.

[0006] The second problem is that when charging is started again immediately after rapid charging is completed with a charger based on these conventional charging methods, the temperature of the sealed nickel cadmium storage battery has already risen. Therefore, the internal pressure of the battery does not increase so much, but in the case of a sealed nickel-metal hydride storage battery, the internal pressure increases.

A third problem is that, when a plurality of batteries are conventionally charged, the voltage of the entire battery group is detected to detect the charging voltage of the batteries. This is a problem that the battery is overcharged with a large current before the charge control is activated. In the case of a sealed nickel-cadmium storage battery, even when deep overcharging is started, the absorption of oxygen gas is promoted by the heat generated by the battery, and the internal pressure of the battery does not increase much. However, in the case of the sealed nickel-metal hydride storage battery, the internal pressure of the battery increases with the heat generation.

A fourth problem is a decrease in discharge voltage after low-temperature overcharge. Conventionally, a method of continuously supplying a charging current corresponding to 1 / 30C to 0.2C in order to compensate for self-discharge after rapid charging is often employed. In the case of a sealed nickel-metal hydride storage battery, unlike a sealed nickel cadmium storage battery, if the amount of overcharged electricity at a low temperature is large, for example, if the battery is overcharged by 500% or more with respect to the standard capacity of the battery in an ambient temperature of 0 ° C. It is inactivated and the discharge voltage drops.

Accordingly, an object of the present invention is to suppress the rise in internal pressure of a sealed nickel-metal hydride battery at the end of charging when charging a plurality of sealed nickel-metal hydride batteries, particularly batteries having a stacked electrode group, and to optimize the battery pressure thereafter. It is an object of the present invention to provide a charging method that solves the four problems by performing a trickle charge, makes full use of the battery capacity, and achieves a long life.

[0010]

In order to achieve the above object, a charging method for a sealed nickel-metal hydride battery according to the present invention comprises: a positive electrode mainly composed of nickel oxide; a negative electrode mainly composed of a hydrogen storage alloy; A charging method for a sealed nickel-metal hydride storage battery using a separator and an alkaline electrolyte as a power generation element, and measures a temperature and a temperature rising rate of a specific portion of the battery,
When one or both of them exceeds a preset value, the initial charging current 10C to 0.1C is stopped or shifted to a current lower than the former and within a range of 0.2C or less once or more. .

The temperature as the set value is 45 ° C. to 60 ° C.
And the rate of temperature rise is preferably in the range of 0.05 to 2 deg / min.

A temperature sensor for detecting the temperature of a specific part of the battery is embedded in the electrode terminal of the battery, installed on the surface of the electrode terminal of the battery and provided with a heat insulating layer so as to cover the electrode terminal, or It is preferably provided in a polypropylene tube placed in a battery case.

The reduction of the charging current may be a discontinuous change or a continuous change. In addition, the amount of charge in the charging area after the decay of the charging current is 6 at a battery temperature of 10 ° C to 20 ° C.
00% or less, 500% or less at 0 ° C to 10 ° C, 0%
When the temperature is lower than 400 ° C., it is preferable to regulate the temperature to 400% or lower.

[0014] As a method of regulating the amount of charged electricity, it is preferable to use a timer for regulating the charging time.

When charging a sealed nickel-metal hydride storage battery having a battery capacity of 10 Ah or more, the total charged amount of electricity is 15
It is preferable to regulate it to 0% or less. Also in this case, it is preferable to use a timer for regulating the charging time as a method of regulating the amount of charged electricity.

When charging a plurality of sealed nickel-metal hydride batteries connected in series, the batteries are divided into one or more groups connected in series, and one or more temperature sensors are arranged for each group. If one of the detected values exceeds the set value, the initial charging current 10C to 0.1C
Is preferably stopped or shifted once or more to a current lower than the former and in the range of 0.2 C or less.

In addition to the temperature detection, it is preferable that charging is stopped when the battery charging voltage exceeds a voltage set in advance corresponding to the temperature of a specific part of the battery. In this case, the voltage setting value is 0 per cell.
1.7V to 1.9V below 0 ° C, 1.6V to above 0 ° C
It is preferably in the range of 1.8V.

Further, the charging method of the sealed nickel-metal hydride storage battery of the present invention comprises a positive electrode mainly composed of nickel oxide;
This is a charging method for a sealed nickel-metal hydride storage battery using a negative electrode having a hydrogen storage alloy as a main material, a separator and an alkaline electrolyte as a power generation element. The ambient temperature is measured, and either or both of the temperature difference between the two or the temperature of a specific part of the battery exceeds a preset value, so that the initial charging current 10C to 0.1C is stopped or lower than the former. In addition, the current is shifted at least once to a current in a range of 0.2 C or less.

The temperature as the set value is 45 ° C. to 60 ° C.
Is preferably in the range of 10 ° C. to 30 ° C.

In the measurement of the environmental temperature, a heat insulating layer is provided between the measurement site and the battery, and the battery is housed in a container having a ventilation port and a thin portion between the measurement site and the outside air. Is preferably measured.

A temperature sensor for detecting the temperature of a specific portion of the battery is preferably provided on the surface of the electrode terminal of the battery, and a heat insulating layer is preferably provided so as to cover the electrode terminal.

The reduction of the charging current may be a discontinuous change or a continuous change. Further, the amount of charge in the charge area after the charge current decay is 6 at a battery temperature of 10 ° C to 20 ° C.
00% or less, 500% or less at 0 ° C to 10 ° C, 0%
When the temperature is lower than 400 ° C., it is preferable to regulate the temperature to 400% or lower.

As a method of regulating the amount of charged electricity, it is preferable to use a timer for regulating the charging time.

Further, when charging a sealed nickel-metal hydride storage battery having a battery capacity of 10 Ah or more, the total charged amount of electricity is 15
It is preferable to regulate it to 0% or less. Also in this case, it is preferable to use a timer for regulating the charging time as a method of regulating the amount of charged electricity.

When charging a plurality of sealed nickel-metal hydride batteries connected in series, a battery group is connected in series.
One or more temperature sensors are arranged for each group, and if any one of the detected values exceeds the set value, the initial charging current 10C to 0.1C is stopped or lower than the former. In addition, it is preferable to shift the current to a current in the range of 0.2 C or less once or more.

In addition to the temperature detection, it is preferable that charging is stopped when the battery charging voltage exceeds a voltage set in advance corresponding to the temperature of a specific portion of the battery. In this case, the voltage setting value is 0 per cell.
1.7V to 1.9V below 0 ° C, 1.6V to above 0 ° C
It is preferably in the range of 1.8V.

The charging method of the sealed nickel-metal hydride storage battery according to the present invention comprises a positive electrode mainly made of nickel oxide, a negative electrode mainly made of a hydrogen storage alloy, and a sealed type using a separator and an alkaline electrolyte as power generating elements. A method of charging a nickel-metal hydride storage battery, in which the temperature of a specific portion of the battery before the start of charging and during charging is measured, and a preset value is set for each of them. When one or both of the temperatures exceed
It is characterized in that the initial charging current 10C to 0.1C is stopped or shifted to a current lower than the former and 0.2C or less once or more.

The set value of the temperature difference between before and after charging the battery is in the range of 10 to 30 ° C., and the set value of the battery temperature during charging is 4
Preferably it is in the range of 5-60 ° C.

A temperature sensor for detecting the temperature of a specific part of the battery is embedded in the electrode terminal of the battery, installed on the surface of the electrode terminal of the battery and provided with a heat insulating layer so as to cover the electrode terminal, or It is preferably provided in a polypropylene tube placed in a battery case.

The reduction of the charging current may be a discontinuous change or a continuous change. Further, the amount of charge in the charge area after the charge current decay is 6 at a battery temperature of 10 ° C to 20 ° C.
00% or less, 500% or less at 0 ° C to 10 ° C, 0%
When the temperature is lower than 400 ° C., it is preferable to regulate the temperature to 400% or lower.

As a method of regulating the amount of charged electricity, it is preferable to use a timer for regulating the charging time.

When charging a sealed nickel-metal hydride battery having a battery capacity of 10 Ah or more, the total amount of charge
It is preferable to regulate it to 0% or less. Also in this case, it is preferable to use a timer for regulating the charging time as a method of regulating the amount of charged electricity.

When charging a plurality of sealed nickel-metal hydride batteries connected in series, the battery group is divided into one or more groups connected in series, and one or more temperature sensors are arranged for each group. If any one of the detected values exceeds the set value, the initial charging current 10C to 0.1
It is preferable that C is stopped or shifted at least once to a current lower than the former and in the range of 0.2 C or less.

In addition to the temperature detection, it is preferable to stop charging when the battery charging voltage exceeds a voltage set in advance corresponding to the temperature of a specific part of the battery. In this case, the voltage setting value is 0 per cell.
1.7V to 1.9V below 0 ° C, 1.6V to above 0 ° C
It is preferably in the range of 1.8V.

The charging method of the sealed nickel-metal hydride storage battery according to the present invention comprises a positive electrode mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy, and a sealed element using a separator and an alkaline electrolyte as power generating elements. A method of charging a nickel-metal hydride storage battery, in which the temperature of a specific part of the battery being charged and the minimum temperature thereof are measured, and the difference between the minimum temperature and the temperature during charging of the battery, one of the battery temperatures or When both of them exceed a preset value for each, the initial charging current 10C to 0.1C is stopped or shifted to a current lower than the former and within a range of 0.2C or less once or more. .

The set value of the difference between the battery minimum temperature and the temperature during charging is preferably in the range of 10 to 30 ° C., and the set value of the battery temperature during charging is preferably in the range of 45 to 60 ° C.

A temperature sensor for detecting the temperature of a specific part of the battery is embedded in the electrode terminal of the battery, installed on the surface of the electrode terminal of the battery and provided with a heat insulating layer so as to cover the electrode terminal, or It is preferably provided in a polypropylene tube placed in a battery case.

The reduction of the charging current may be a discontinuous change or a continuous change. Further, the amount of charge in the charge area after the charge current decay is 6 at a battery temperature of 10 ° C to 20 ° C.
00% or less, 500% or less at 0 ° C to 10 ° C, 0%
When the temperature is lower than 400 ° C., it is preferable to regulate the temperature to 400% or lower.

As a method of regulating the amount of charged electricity, it is preferable to use a timer for regulating the charging time.

When charging a sealed nickel-metal hydride storage battery having a battery capacity of 10 Ah or more, the total amount of charge is 15
It is preferable to regulate it to 0% or less. Also in this case, it is preferable to use a timer for regulating the charging time as a method of regulating the amount of charged electricity.

In order to charge a plurality of sealed nickel-metal hydride storage batteries connected in series, the battery group is divided into one or more groups connected in series, and one or more temperature sensors are arranged for each group. If any one of the detected values exceeds the set value, the initial charging current 10C to 0.1C
It is preferable that C is stopped or shifted at least once to a current lower than the former and in the range of 0.2 C or less.

In addition to the temperature detection, it is preferable to stop charging when the battery charging voltage exceeds a voltage set in advance corresponding to the temperature of a specific part of the battery. In this case, the voltage setting value is 0 per cell.
1.7V to 1.9V below 0 ° C, 1.6V to above 0 ° C
It is preferably in the range of 1.8V.

Further, the charging method of the sealed nickel-metal hydride storage battery of the present invention comprises a positive electrode mainly composed of nickel oxide,
This is a charging method for a sealed nickel-metal hydride storage battery that uses a hydrogen storage alloy as a main material, a separator and an alkaline electrolyte as a power generation element, and measures the temperature and charging voltage of a specific part of the battery, and is provided in advance. The first determination condition is that the battery temperature exceeds the set value, and that the time derivative of the charging voltage changes from positive to 0 or negative, or that the value falls below a predetermined value from positive to negative, A second determination condition is obtained by combining at least one of a decrease in the charging voltage from a maximum value of the voltage to a value equal to or more than a preset value, and the initial charging current 10C is set according to one or both of the two determination conditions.停止 0.1 C is stopped or the current is shifted at least once to a current lower than the former and 0.2 C or less.

The set value of the temperature is preferably in the range of 45 ° C. to 60 ° C. In addition, a temperature sensor that detects the temperature of a specific part of the battery is embedded in the electrode terminal of the battery,
It is preferable to provide a heat insulating layer so as to cover the electrode terminal surface of the battery and cover it, or to provide it in a polypropylene tube arranged in a battery case of the battery.

The reduction of the charging current may be a discontinuous change or a continuous change. Further, the amount of charge in the charge area after the charge current decay is 6 at a battery temperature of 10 ° C to 20 ° C.
00% or less, 500% or less at 0 ° C to 10 ° C, 0%
When the temperature is lower than 400 ° C., it is preferable to regulate the temperature to 400% or lower.

As a method of regulating the amount of charged electricity, it is preferable to use a timer for regulating the charging time.

When charging a sealed nickel-metal hydride storage battery having a battery capacity of 10 Ah or more, the total charged amount of electricity is 15
It is preferable to regulate it to 0% or less. Also in this case, it is preferable to use a timer for regulating the charging time as a method of regulating the amount of charged electricity.

In order to charge a plurality of sealed nickel-metal hydride storage batteries connected in series, the battery group is divided into one or more groups connected in series, and one or more temperature sensors are arranged for each group. When one of the detected values exceeds the set value, it is preferable to stop the initial charging current 10C to 0.1C or shift it to a current lower than the former and 0.2C or less once or more.

In addition to the above-mentioned charge control, it is preferable to stop charging when the battery charging voltage exceeds a voltage set in advance corresponding to the temperature of a specific part of the battery. In this case, the voltage setting value is 0 per cell.
1.7V to 1.9V below 0 ° C, 1.6V to above 0 ° C
It is preferably in the range of 1.8V.

Further, the charging method of the sealed nickel-metal hydride storage battery of the present invention comprises a positive electrode mainly composed of nickel oxide,
This is a charging method for a sealed nickel-metal hydride storage battery using a negative electrode mainly composed of a hydrogen storage alloy as a main material, a separator and an alkaline electrolyte as a power generation element, and has a charging current of 10 C.
When charging is performed at 0.1 C for several seconds to several minutes and the charging voltage is higher than a predetermined value, the initial charging current 10 C to 0.1 C is stopped or reduced to a current lower than the former and 0.2 C or less.
The feature is to shift more than once.

In measuring the charging voltage, it is preferable that the charging current is cut off and the battery voltage after several μsec to several tens of msec is measured.

In the case of charging a battery group in which a plurality of sealed nickel-metal hydride batteries are connected in series, the battery group is divided into blocks corresponding to the number of power supplies by using a plurality of power supplies, and the divided battery groups are charged. It is preferable to detect the charging voltage for each of the same or smaller number of batteries.

The charging method of the sealed nickel-metal hydride storage battery of the present invention is equivalent to the number of power supplies using one or a plurality of power supplies when charging a battery group in which a plurality of sealed nickel-metal hydride storage batteries are connected in series. The battery group is divided into blocks to be charged and charged, and the divided battery group is divided into small blocks for each number of batteries equal to or smaller than the divided battery group, and the charge voltage is detected. When the spread of the charging voltage distribution of the small block is detected and is larger than a predetermined value, the charging current is changed to a current value of 0.2 C or less and lower than the previous charging current.

The charging method of the sealed nickel-metal hydride storage battery according to the present invention, when charging a battery group in which a sealed nickel-metal hydride storage battery having a plurality of stacked electrode groups is connected in series, requires charging between the individual batteries. A plurality of battery groups are sandwiched between plates having good thermal conductivity in the electrode plate stacking direction, and charging is performed while applying pressure from both sides.

The heat conductive plate preferably has a hole penetrating at right angles to the pressing direction and parallel to the direction of gravity.

Further, it is preferable that the heat conductive plate has a hole penetrating at right angles to the pressurizing direction, and a refrigerant is allowed to flow therein during charging.

As the material of the heat conductive plate, Al, M
g, Cu, Ag, Ti or any of these 2-5
It is preferable to use a single metal plate mainly composed of a mixture of species or a plate made by combining members made of these materials.

The charging method of the sealed nickel-metal hydride storage battery according to the present invention includes a positive electrode having a nominal capacity of 10 Ah or more and mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy, a separator and an alkaline electrolyte. A method of charging a sealed nickel-metal hydride storage battery using liquid as a power generation element, wherein the time derivative of the charging voltage changes from positive to 0 or negative, or falls below a predetermined positive to negative value. It is characterized by stopping charging.

The batteries may be a plurality of batteries connected in series. Further, the charging method of the sealed nickel-metal hydride storage battery of the present invention includes a positive electrode mainly composed of nickel oxide, a negative electrode mainly composed of a hydrogen storage alloy, and a sealed nickel nickel battery having a separator and an alkaline electrolyte as power generating elements. A method for charging a hydrogen storage battery, wherein an initial charging current is 10 C
0.1C is stopped or lower than the former and 0.1C.
In transitioning to a current in the range of 2C or less, an amount of electricity of 5% or less of the nominal capacity of the battery is discharged.

[0060]

According to the charging method of the sealed nickel-metal hydride storage battery of the present invention, the first problem described in the above-mentioned problem to be solved is solved by a conventional method for detecting an increase in the internal pressure of the battery, The battery temperature detection is combined with the temperature speed detection, the battery temperature rise detection, the detection of the flat portion of the charging voltage or the detection of the decay of the charging voltage. The former detects an increase in internal pressure due to oxygen generated from the positive electrode at the end of charging, and the latter detects an increase in hydrogen absorption equilibrium pressure due to a temperature increase and a corresponding increase in battery internal pressure, thereby suppressing an increase in battery internal pressure. Therefore, in order to more accurately measure the temperature of the battery, a temperature sensor is attached to the surface of the battery terminal and a heat insulating layer is provided on it to make it less affected by the ambient temperature, and the temperature sensor is embedded inside the battery terminal. , For example, in a polypropylene tube placed in a battery case. In addition, when the connection between the battery terminal and the lead wire is screwed, conductive powder or liquid is applied to the screw part to reduce the contact resistance, suppress the generation of Joule heat during charging, and measure the battery temperature. Improve accuracy. In addition, the battery being charged is cooled to suppress an increase in battery internal pressure. When charging a plurality of batteries formed by laminating a large number of electrodes, charging has been conventionally performed while pressing with a plate in order to prevent the electrode group from expanding in the stacking direction. Is made of a heat conductive material, and efficient cooling can be performed by passing a hole or a cooling air or cooling medium through the inside of the plate. In the case of a battery having a nominal capacity of 10 Ah or more, it may be difficult to detect the temperature inside the battery. In such a case, it is effective to detect the maximum value or decrease of the charging voltage. When such a detection occurs, the internal pressure of the battery is increased. However, if a very small amount of electricity is discharged, the hydrogen concentration on the negative electrode surface decreases, the hydrogen absorption reaction is accelerated, and the internal pressure of the battery is reduced.

The energy converted into heat is supplied by charging but does not contribute to discharging. Such an increase in internal pressure can also be achieved by not supplying excessive charging energy. In particular, in a battery having a nominal capacity exceeding 10 Ah, overcharging of 150% or more is not preferable in terms of energy efficiency.

For the second problem, the state of charge of the battery is determined based on the charging voltage at the start of charging, the charging current is reduced, and the rise in battery internal pressure is suppressed. At this time, the charging voltage of the battery fluctuates due to the internal resistance of the battery.
It is more accurate to measure the battery voltage after scc to several tens of mscc.

For the third problem, the battery group to be charged is divided and the charging current is controlled in accordance with the battery group having the highest charging voltage among the individual battery groups. When the variation width of the charging voltage is large, it is determined that batteries having different charging states are mixed, and the charging current is controlled to suppress an increase in battery internal pressure of a battery having a large amount of charged electricity.

For the fourth problem, the temperature of the battery is measured at the time of trickle charging, and the lower the temperature, the smaller the amount of overcharged electricity.
At 20 ° C. or higher, by not regulating the amount of charge, self-discharge at a high temperature is compensated, and inactivation of the negative electrode at a low temperature is suppressed.

[0065]

Embodiments of the present invention will be described below. (Example 1) First, a sealed nickel-metal hydride storage battery as shown in FIG. 1A and a sealed nickel cadmium storage battery as shown in FIG. 1B were prepared as follows.

A LaNi ₅ hydrogen storage alloy known as a negative electrode (hydrogen dissociation pressure at 45 ° C. H / M = 1/0; about 6 × 1
0 ⁴ Pa) in an inert gas to obtain a powder having a particle size of 300 mesh or less. A polymer binder was added to the alloy powder, and the foamed metal porous body of the electrode support was filled and pressed to obtain a hydrogen storage electrode 1. Similarly, oxidized cadmium electrode 2 was prepared using commercially available oxygen cadmium powder. On the other hand, a known nickel electrode 3 is used as a positive electrode, and a nickel lead plate 4 is welded to these electrodes 1, 2, 3 to form a bag-shaped separator 5.
Inserted inside. In the sealed nickel-metal hydride battery, two nickel electrodes 3 as a positive electrode and three hydrogen storage electrodes 1 as a negative electrode are alternately stacked and welded to a pole 6 for current collection, and inserted into a battery case 7 made of polypropylene. Then, a cover plate 8 made of polypropylene was welded from above. In the sealed nickel cadmium storage battery, two nickel electrodes 3 each as a positive electrode and three cadmium oxide electrodes 2 each as a negative electrode are alternately stacked and welded to a pole 6 for current collection. And a lid plate 8 made of polypropylene was welded from above. Then, in both batteries, a sealing O-ring 11 and a washer 12 were set on the pole 6 as shown in FIG.
Further, about 100 cc of a KOH aqueous solution was injected, and a safety valve 10 was attached to produce a sealed nickel-metal hydride storage battery having a nominal capacity of 40 Ah and a sealed nickel cadmium storage battery having a nominal capacity of 30 Ah.

Next, chargers A to L shown in Table 1 were prepared by combining a commercially available constant current charger, a temperature measuring device, a voltage measuring device, and a control device.

[0068]

[Table 1]

Each charging terminal and voltage detecting terminal were connected to the pole of the battery with a cable and fixed with a nut. In addition, a hole having a depth of 20 mm and a diameter of 2φ was formed in the pole and the temperature sensor was inserted therein. The chargers A to H were connected to sealed nickel-metal hydride batteries, and the chargers I to L were connected to sealed nickel cadmium storage batteries. Environmental temperature 0 ℃ and 35 ℃ with the above configuration
A life test was performed. The results are shown in FIGS. 5A and 5B. In conducting the life test, charging was performed for 5 hours, and discharging was performed at a constant current of 5 hours of the nominal capacity, and the battery was stopped when the battery voltage fell below 1V. As shown, the chargers A to A according to the present invention.
D showed good results at both 0 ° C. and 35 ° C.
~ H deteriorated at 35 ° C. This is presumably because the initial charge amount was too large, and the closed system was destroyed. However, the sealed nickel cadmium storage battery is a conventional charger I ~
No deterioration occurred even when L was used. As described above, particularly at high temperatures, when the charging method according to the present invention is used, the internal pressure rise of the sealed nickel-metal hydride storage battery is suppressed, and the life characteristics are improved. In the case of the chargers B and F, the installation position of the temperature sensor that measures the environmental temperature difference affects the accuracy of detecting the completion of charging. In this study, measurements were taken sufficiently away from the battery, but if such a configuration could not be obtained, some measures such as providing a heat insulating layer between the battery and the battery would be necessary. Further, better results were obtained by using a charger having the same configuration as that of the charger D and discharging 0.5 Ah after detecting the V peak. (Embodiment 2) Two types of a sealed nickel-metal hydride storage battery prepared in Embodiment 1 and a temperature sensor installed using a charger having the same specifications as the charger A based on the present invention, and one type of a conventional example Was configured. First, as shown in FIG. 2A, when fixing the lead 13 of the pole 6, the pole 6 and the lead 1 are fixed.
3. A commercially available silver paste 14 was applied to the surface in contact with the nut 9. Thereafter, a hole 15 having a depth of 20 mm and a diameter of 3φ was formed in the center of the pole 6, and silicone grease was applied to a commercially available thermocouple 16 having a thickness of 1 mm as a temperature sensor, and inserted and fixed. This charger is designated as M. Next, as shown in FIG. 2 (B), a thermocouple 16 was fixed with an adhesive 17 on the upper part of the pole 6 to which the lead 13 was similarly fixed with the nut 9, and a heat insulating material 18 was further bonded thereon. . This charger is designated as N. Further, as a conventional example, as shown in FIG. 2C, a thermocouple 14 was similarly fixed with an adhesive 17 on the upper part of the pole 6 to which the lead 11 was fixed without using a silver paste. This charger is designated as O. The battery life test was performed at room temperature (in an environment fluctuating at 20 ° C. ± 5) using the chargers M to O described above. In conducting the life test, charging was performed for 5 hours, and discharging was performed at a constant current of 5 hours of the nominal capacity. FIG. 6 shows the results. As shown in the figure, the chargers M and N according to the present invention secure a stable discharge capacity, but in the conventional example O, the charge is quickly cut off or not cut off and the capacity is not stable. When charging / discharging of about 200 cycles was completed, salting was observed in the O sealed nickel-metal hydride battery near the safety valve. Thus, in an environment where the temperature fluctuates,
It can be seen that if the temperature sensor is simply adhered to the surface of the battery, a control malfunction may occur due to a change in environmental temperature. According to the present invention, such effects can be prevented by embedding the temperature sensor in the pole or bonding the temperature sensor to the pole surface and covering with a heat insulating material. Further, the one coated with silver paste was also effective in improving the discharge voltage. (Embodiment 3) The sealed nickel-metal hydride storage battery and the sealed nickel cadmium storage battery prepared in Example 1 were discharged by the chargers P to R having the specifications shown in (Table 2) which were also configured with the equipment used in Example 1. A life test was performed.

[0070]

[Table 2]

The test was conducted at an ambient temperature of 20 ° C. in the order of 5 hours of charging, 10 minutes of rest, 5 hours of charging, and discharging, and this cycle was repeated for about 200 cycles. The chargers P and Q were combined with a sealed nickel-metal hydride storage battery, and the charger R was combined with a sealed nickel-cadmium storage battery. FIG. 7 shows the life test results. Those using the charger P exhibited a stable discharge capacity from the initial stage to 200 cycles. Almost the same results were obtained for the charger R, but the one using the charger Q showed a sharp decrease in capacity.
Thus, the sealed nickel-metal hydride storage battery is more vulnerable to overcharge than the sealed nickel cadmium storage battery. The deterioration due to recharging can be prevented by examining whether or not recharging is performed at the beginning of charging with the charging voltage. (Embodiment 4) As shown in FIG. 4 (A), five sealed nickel-metal hydride storage batteries 20 prepared in Embodiment 1
Holes 1cm thick and 8mm in diameter at the top and bottom between cells and at both ends
9 are opened, and an aluminum plate 22 is tightened with a contact bolt 23 and a nut 24 to form a battery group AA. A total of 24 same battery groups AA are created, and the chargers S and T whose specifications are shown in (Table 3) and the charger U and FIG. 3 (B) as shown in FIG. Wiring as shown in (1). Note that FIG.
Medium 30 is a current line, 31 is a voltage line, 32 is a power control line, 3
3 is power supply,

[0072]

[Table 3]

Reference numeral 34 denotes a power supply control device. A life test was performed at room temperature using these chargers. The evaluation conditions were as follows: charging at room temperature for 2 days; O. C. 50%
This was performed as one cycle. The battery was completely discharged after charging for 2 days every 10 cycles, and the capacity was confirmed. The result is shown in FIG.
Shown in T has the least capacity deterioration, and the capacity deteriorates in the order of S and U. This is because each cell self-discharges after the completion of charging and the remaining capacity varies, but U cannot detect the difference and some cells are overcharged and the capacity is reduced. The detection accuracy of the variation in the remaining capacity of the battery is improved in the order of U, S, and T, and accordingly, the decrease in capacity is reduced. (Example 5) Using the sealed nickel-metal hydride battery prepared in Example 1, a capacity test was performed at ambient temperatures of 0 ° C and 35 ° C by controlling the charging of the chargers V, W and X shown in (Table 4). .

[0074]

[Table 4]

The charging was performed for one week, and thereafter, the discharge capacity at 0.2 C was confirmed. The results are shown in (Table 5).

[0076]

[Table 5]

Only in the charger X according to the present invention, the amount of discharged electricity exceeded 40 Ah under both the conditions of 0 ° C. and 35 ° C. It was found that the charger V without the trickle charge control caused inactivation of the negative electrode during low-temperature trickle charge. In addition, although the timer operated at the time of trickle charge did not inactivate at a low temperature, the trickle charge was cut off at a high temperature, and the capacity was reduced by self-discharge. Also, when such deep overcharging is performed, the battery generates significant heat. In the present embodiment, the heat is released by blowing air so that the battery temperature becomes equal to or lower than the environmental temperature plus 5 ° C. However, under the condition that the heat can not be sufficiently released, it is necessary to suppress the amount of overcharge electricity to 150% or less. Under the same conditions as in the present example and under the condition of insufficient heat radiation, valve operation was observed in the battery unless the charged amount of electricity was suppressed to 150% or less. (Embodiment 6) The sealed nickel-metal hydride storage batteries AA, AB, and AC having the configurations shown in FIGS. 4A, 4B, and 4C are created using the sealed nickel-metal hydride storage battery prepared in Example 1. I do. FIG. Instead of the perforated aluminum plate 22 shown in FIG. 4A, a hole is provided that penetrates at right angles to the tightening direction, and a refrigerant pipe 25 is inserted through the hole. 4C is used, and FIG.
A bakelite plate 28 was used in place of the perforated aluminum plate 21 in (A).

These battery groups were charged at a charging current of 40 A and 45 ° C.
Ambient temperature 35 using a temperature control + V peak control charger
A life test was performed at ℃. Charge time is 4 hours and discharge is 8
A was performed up to 1 V / cell. During charging, the battery group AB was cooled by supplying 1 liter of water at 20 ° C. per minute from a cooling supply pipe. FIG. 9 shows the results. It can be seen that the heat dissipated in this manner shows a higher capacity than the initial one and also has a good life performance.

As described above, according to the present invention, it is possible to obtain a sufficient amount of charged electricity and a sufficient battery life for charging a plurality of batteries, particularly those having an electrode group having a laminated structure.

[0080]

As described above, according to the charging method of the sealed nickel-metal hydride storage battery of the present invention, the conventional method for detecting an increase in the internal pressure of the battery, detecting the rate of temperature rise of the battery, detecting the temperature rise of the battery, and flattening the charging voltage. Accurate charge control can be performed by combining the detection of the unit or the detection of the decrease in the charging voltage with the battery temperature detection, and a high discharge capacity can be secured by combination with the optimal trickle charging method.

[Brief description of the drawings]

FIG. 1A is a partial cross-sectional view of a unit cell of a sealed nickel-metal hydride battery used for evaluation of a charger based on the present invention. FIG. 1B is a partial cross-sectional view of a unit cell of the sealed nickel-cadmium storage battery.

FIGS. 2A and 2B are explanatory diagrams each showing a mounting state of a temperature sensor according to the present invention; and FIG. 2C is an explanatory diagram showing a mounting state of a conventional temperature sensor.

FIG. 3 (A) is a battery charging circuit diagram according to the present invention, and (B) is a battery charging circuit diagram according to a conventional method.

4A and 4B are perspective views of a battery group according to the present invention, and FIG. 4C is a perspective view of a battery group according to a conventional method.

FIGS. 5 (A) and (B) show environmental temperatures of 0 ° C. and 35 ° C., respectively.
Characteristic diagram showing the result of battery life test at ℃

FIG. 6 is a characteristic diagram showing the results of a battery life test.

FIG. 7 is a characteristic diagram showing a result of a battery life test.

FIG. 8 is a characteristic diagram showing a result of a battery life test.

FIG. 9 is a characteristic diagram showing a result of a battery life test.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 hydrogen storage electrode 2 cadmium oxide electrode 3 nickel electrode 4 lead plate 5 separator 6 pole 7 battery case 8 lid plate 9 nut 10 safety valve 11 O-ring 12 washer 13 lead 14 paste 15 hole 16 thermocouple 17 adhesive 18 heat insulating material 21 Hole 22 Aluminum plate 23 Bolt 24 Nut 25 Refrigerant pipe 26 Refrigerant supply pipe 27 Aluminum plate 28 Bakelite plate 30 Current line 31 Voltage line 32 Power control line 33 Power supply 34 Current control line

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Hiroharu Takada 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (56) References JP-A-4-109828 (JP, A) JP-A-63- 157623 (JP, A) JP-A-4-208033 (JP, A) JP-A-4-217826 (JP, A) JP-A-47-40134 (JP, A) JP-A-3-54333 (JP, U) (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J ^7/ 00-7/12 H02J ⁷ /34-7/36 H01M 10/42-10/48 301

Claims (6)

(57) [Claims] 1. A divided with charges by dividing the cell group to the block corresponding to the power supply quantity using one or more of power per multiple sealed nickel-metal hydride storage battery to charge the battery group that has been connected in series is divided into small blocks every the same or even smaller cell number and cell group detects the charging voltage to charge at 10C~0.1C the initial charging, predetermined detect the spread of the distribution of the charging voltage of each small block Wherein the charging current is changed to a current value of 0.2 C or less and lower than the previous charging current when the value is larger than the value of the charging current. 2. A per a sealed nickel-metal hydride storage battery having an electrode group of the plurality of laminated structures <br/> to charge the cell group which is connected in series, the thermal conductivity in the electrode plate group laminating direction between the individual cells A method for charging a sealed nickel-metal hydride storage battery, comprising a plurality of battery groups sandwiched between plates having good properties and charging while applying pressure from both sides. 3. The charging method according to claim 2, wherein the heat conductive plate has a hole penetrating at right angles to the pressing direction and parallel to the direction of gravity. 4. The charging method according to claim 2 , wherein the heat conductive plate has a hole penetrating at right angles to the pressurizing direction, and the refrigerant flows into the inside of the hole during charging. 5. A heat conductive plate made of Al, Mg,
3. A metal plate containing one of Cu, Ag, and Ti or a mixture of 2 to 5 of them as a main component, or a plate formed by combining members made of these materials.
The charging method described. 6. A positive electrode mainly composed of nickel oxide,
This is a charging method for a sealed nickel-metal hydride storage battery using a negative electrode having a hydrogen storage alloy as a main material, a separator and an alkaline electrolyte as a power generating element, and has an initial charging current of 10 C to 0.1 C.
0 of nominal capacity per cell to migrate either stop C, or to the current in the low and 0.2C the range from former
Charging method of the sealed type nickel hydrogen storage battery, characterized in that the discharge% than the size rather than 5% of the quantity of electricity.