JP2003217677A - Charging/discharging control device for nickel hydrogen battery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging/discharging control device for a nickel hydrogen battery, capable of detecting performance deterioration of the nickel hydrogen battery by discriminating the performance deterioration due to memory effect and that due to another factor. <P>SOLUTION: A controller 5 performs refreshing for recovering a chargeable capacity of the nickel hydrogen battery 2 decreased due to the memory effect. At the completion of refreshing, the nickel hydrogen battery 2 is determined to be deteriorated due to a factor other than the memory effect when the integrated value of a discharging current from the start of discharging from the nickel hydrogen battery 2 to a running motor 9 until the discharged depth of the nickel hydrogen battery 2 reaches a designated discharge stop level becomes smaller than a designated deterioration value, and information to urging replacement of the nickel hydrogen battery 2 is given. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nickel-hydrogen battery charge / discharge control device for detecting performance deterioration of a nickel-hydrogen battery.

[0002]

2. Description of the Related Art For example, a nickel hydrogen battery is used as a driving power source for an electric vehicle. Then, in the electric vehicle, the integrated value of the discharge current from the time when the discharge to the load such as the traveling motor is started in the fully charged state until the output voltage of the nickel-hydrogen battery reaches the predetermined discharge stop level is When the integrated value falls below a predetermined value,
When it is judged that the performance of the nickel-hydrogen battery has deteriorated, a notification prompting replacement of the nickel-hydrogen battery is given.

However, the nickel-metal hydride battery has a low SOC (State Of Cha) at a point where the temperature of the nickel-metal hydride battery starts to rise during charging when charging is repeated at high temperature.
rge) side to the side (so-called memory effect). Then, in the charging process of the nickel-hydrogen battery, it is common to determine that the nickel-hydrogen battery is fully charged when the temperature increase rate of the nickel-hydrogen battery reaches a predetermined level after the start of charging, and terminate the charging process. Is.

Therefore, when the starting point of the temperature rise of the nickel-hydrogen battery shifts to the low SOC side due to the memory effect, the nickel-hydrogen battery is actually in a fully charged state (SOC10).
The temperature rise rate of the nickel-metal hydride battery reaches the predetermined level before the charging process ends before it becomes 0%), and in this case, the chargeable capacity of the nickel-metal hydride battery decreases.

As a result, the integrated value of the discharge current of the nickel-hydrogen battery from the time when the discharge to the load is started after the charging is completed until the output voltage of the nickel-hydrogen battery reaches the discharge stop level, It is determined that the performance of the nickel-hydrogen battery has deteriorated, and the above-mentioned notification prompting the replacement of the nickel-hydrogen battery is performed.

However, the state in which the chargeable capacity of the nickel-hydrogen battery has decreased due to the memory effect described above can be resolved by a process such as overcharging the nickel-hydrogen battery. Therefore, the performance deterioration of the nickel-hydrogen battery due to the memory effect and the performance deterioration of the nickel-hydrogen battery due to factors other than the memory effect are detected separately, and only when the performance deterioration of the nickel-hydrogen battery occurs due to the factors other than the memory effect. It is desirable to be informed that the nickel hydrogen battery should be replaced.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above background, and can detect the performance deterioration of a nickel hydrogen battery due to the memory effect separately from the performance deterioration due to other factors. It is an object of the present invention to provide a charge / discharge control device of

[0008]

The present invention has been made in order to achieve the above-mentioned object, and has an electric vehicle having a nickel-hydrogen battery and using the nickel-hydrogen battery as a driving power source. Alternatively, the present invention relates to an improvement of a charge / discharge control device for a nickel hydrogen battery that supplies current to an electric load of a hybrid vehicle and charges the nickel hydrogen battery.

Then, a discharge depth grasping means for grasping the discharge depth of the nickel-hydrogen battery, a charging means for performing a capacity recovery charge for recovering the chargeable capacity of the nickel-hydrogen battery, and a state in which the capacity recovery charge is completed. When the integrated value of the discharge current from the start of the discharge from the nickel-hydrogen battery to the load until the depth of discharge of the nickel-hydrogen battery reaches a predetermined discharge stop level is less than a predetermined integrated value, A deterioration detecting unit that determines that the nickel-hydrogen battery has deteriorated is provided.

According to the present invention, from the start of discharge from the nickel-hydrogen battery to the load until the depth of discharge of the nickel-hydrogen battery reaches the discharge stop level, despite performing the capacity recovery charge. When the integrated value of the discharge current becomes smaller than the predetermined integrated value, it can be determined that it is impossible to recover the chargeable capacity of the nickel hydrogen battery. Therefore, in such a case, the deterioration detection unit determines that the nickel hydrogen battery has deteriorated. Thus, when recoverable deterioration occurs in the nickel-hydrogen battery, a process for recovering the chargeable capacity of the nickel-hydrogen battery by the capacity recovery charging is performed, and the unrecoverable deterioration occurs in the nickel-hydrogen battery. In this case, it is possible to perform a process for prompting the replacement of the nickel-hydrogen battery.

The charging / discharging control means includes a battery temperature sensor for detecting the temperature of the nickel-hydrogen battery, and when the temperature detected by the battery temperature sensor becomes equal to or lower than a predetermined capacity recovery charging start temperature, It is characterized by performing capacity recovery charging.

According to the present invention, when the temperature of the nickel-hydrogen battery falls below the capacity-recovery charge start temperature, the charge-discharge control means executes the capacity-recovery charge so that the nickel-hydrogen battery can be controlled. The effect of battery capacity recovery can be enhanced.

Further, cooling means for cooling the nickel-hydrogen battery, an outside air temperature sensor for detecting a temperature in the vicinity of the cooling means, and a temperature detected by the battery temperature sensor are higher than the capacity recovery charging start temperature, and A cooling control means for operating the cooling means to cool the nickel-hydrogen battery only when the temperature detected by the outside air temperature sensor is lower than the temperature detected by the battery temperature sensor by a predetermined temperature difference or more. Characterize.

According to the present invention, the cooling control means determines that the temperature in the vicinity of the cooling means is lower than the temperature of the nickel-hydrogen battery by the predetermined temperature difference or more, and the cooling effect on the nickel-hydrogen battery is high. The cooling means is activated only when possible. And this
It is possible to prevent the cooling means from operating unnecessarily when the cooling effect is low.

Further, the charging means supplies a constant charging current to the nickel-hydrogen battery and starts supplying the charging current to the nickel-hydrogen battery so that an integrated value of the charging current from the start is predetermined. The capacity recovery charging can be performed by repeating the process of stopping the supply of the charging current when the value becomes equal to or more than the charging stop value.

Further, a battery temperature detection sensor for detecting the temperature of the nickel-hydrogen battery is provided, and a constant charging current is supplied to the nickel-hydrogen battery, and the charging current is supplied to the nickel-hydrogen battery to start the charging. The charging means can also perform the capacity recovery charging by repeating the process of stopping the supply of the charging current when the rate of increase in the temperature detected by the battery temperature sensor becomes equal to or higher than the predetermined level.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is an overall configuration diagram of a charge / discharge control device for a nickel-hydrogen battery of the present invention, FIG. 2 is a flow chart of charge / discharge processing of a nickel-hydrogen battery by the charge-discharge control device shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a flowchart of a nickel-hydrogen battery charging process by the charge / discharge control device, and FIG. 4 is a flowchart of a nickel-hydrogen battery refresh charging process by the charge / discharge control device shown in FIG.

Referring to FIG. 1, a charge / discharge control device 1 for a nickel-hydrogen battery (hereinafter, simply referred to as charge / discharge control device 1).
Is installed in an electric vehicle or a hybrid vehicle that uses a nickel-hydrogen battery as a driving power source.
A battery box 3 in which (2a to 2h) are connected in series, a charging circuit 4 that charges the nickel hydrogen battery 2, a controller 5 that controls the operation of the charge / discharge control device 1, and a cooling system 6 that cools the nickel hydrogen battery 2 ( (Corresponding to the cooling means of the present invention), a battery temperature sensor 7 that detects the temperature of the nickel-hydrogen battery 2, an outside air temperature sensor 6 that detects the outside air temperature, and a DC voltage output from the battery box 3 for the traveling motor 9 (the book). Equivalent to the load of the electric vehicle of the invention)
Inverter 1 for converting into three-phase AC voltage for driving
0, a voltage sensor 11 that detects the output voltage of the battery box 3, and a current sensor 12 that detects the output current of the battery box 3.

The cooling system 6 has a circulation circuit 20 partially provided near the nickel-hydrogen battery 2 in the battery box 3, a pump 21 for circulating a refrigerant in the circulation circuit 20, and a circulation circuit. The circuit 20 includes a radiator 22 provided in the middle of the circuit 20, and a cooling fan 23 that blows air to the radiator 22 to cool the refrigerant passing through the radiator 22. The outside air temperature sensor 8 is provided in the vicinity of the radiator 22 and detects the ambient temperature of the radiator 22. When charging the nickel-hydrogen battery 3, the charging circuit 4 is connected to the AC power supply 25.

The controller 5 (including the functions of the discharge depth grasping means, the charging means, and the deterioration detecting means of the present invention) is C
An electronic unit composed of PU, RAM, etc.,
Detection signals from the battery temperature sensor 7, the outside air temperature sensor 8, the voltage sensor 11, and the current sensor 12 are input to the controller 5. Further, the control signal output from the controller 5 controls the operations of the charging circuit 4, the pump 21, and the cooling fan 23.

Next, the operation of the charge / discharge control device 1 will be described with reference to the flowcharts shown in FIGS.

In step 1 of FIG. 2, when the nickel-hydrogen battery 2 is completely charged and the driver of the electric vehicle operator turns on the ignition and starts running the electric vehicle in step 2, the inverter 10 is switched from the nickel-hydrogen battery 2 to the vehicle. Through this, the supply of electric current to the traveling motor 9 is started. And
In the subsequent STEP 3, the controller 5 causes the current sensor 12
The discharge current (Ibat) of the nickel-hydrogen battery 2 is detected based on the current detection signal from, and integration of the discharge current of the nickel-hydrogen battery 2 is started.

At the next STEP 4, the controller 5 detects the output voltage (Vbat) of the nickel-hydrogen battery 2 detected based on the voltage detection signal from the voltage sensor 11, and detects the output voltage (Vbat) from the nickel-hydrogen battery. The discharge depth of 2 is grasped, and when the discharge depth reaches the discharge stop level, the process proceeds to STEP 5 to stop the discharge of the nickel hydrogen battery 2. Then, in STEP 6, the controller 5 sets S
The integrated value of the discharge current until the discharge is stopped at TEP5 is compared with the deterioration determination value (corresponding to the predetermined integrated value of the present invention).

When the integrated value of the discharge current is equal to or higher than the deterioration determination value in STEP 6, the controller 5 determines that the chargeable capacity of the nickel-hydrogen battery 2 has not decreased, and proceeds to STEP 7 to proceed to the nickel-hydrogen battery. No. 2 temporary capacity drop flag (F
tem) is reset (Ftem = 0), and the charging process shown in FIG. 3 is executed in the next STEP8.

On the other hand, when the integrated value of the discharge current is smaller than the deterioration determination value in STEP 6, the controller 5
Judges that the chargeable capacity of the nickel-hydrogen battery 2 has temporarily decreased due to the so-called memory effect, and the STEP10
And the deterioration determination permission flag (Fj) is set (Fj =
1) Check whether it has been done.

Here, the deterioration determination permission flag (Fj) is
Nickel-metal hydride battery temporarily reduced due to memory effect 2
Is set when a refresh charge (described later in detail) performed to restore the chargeable capacity of the is executed for a predetermined cycle. Therefore, STEP1
When the deterioration determination permission flag (Fj) is set to 0, it is possible to determine that the chargeable capacity of the nickel-hydrogen battery 2 has not recovered despite refresh charging.

Therefore, in this case, it is determined that the nickel-hydrogen battery 2 is deteriorated due to factors other than the memory effect, and it is impossible to recover the chargeable capacity of the nickel-hydrogen battery 2, and the process branches from STEP 10 to STEP 15. The controller 5 displays the nickel-hydrogen battery 2 on the driver's seat display or the like.
Display to prompt replacement of.

On the other hand, in STEP 10, the deterioration determination flag (F
When j) is not set (Fj = 0), it can be determined that the charge amount of the nickel hydrogen battery 2 when the normal charging is completed is less than the deterioration determination value. Therefore, in this case, the controller 5 determines that the chargeable capacity of the nickel-hydrogen battery 2 has temporarily decreased due to the memory effect, and the controller 5 sets the temporary capacity decrease flag (Fj) in STEP 11 (Fj = 1). Then, in STEP 8, refresh charging is executed for a predetermined cycle.

Next, FIG. 3 shows a flow chart of a "charging process" subroutine for performing the normal charging process and the process for executing the refresh charging for a predetermined cycle.
In STEP 8, the "charging process" subroutine is called. In the "charging process" subroutine, the process of performing refresh charging a predetermined number of times corresponds to the capacity recovery charging of the present invention.

When the "charge process" subroutine is called, the controller 5 first confirms in STEP 21 of FIG. 3 whether the temporary capacity decrease flag (Fj) is set. Then, when the temporary capacity flag (Fj) is not set (Fj = 0), STEP30
Branch to and execute "normal charge". That is, a constant charging current is supplied to the nickel-hydrogen battery 2, and charging is performed when the rate of increase in the temperature (Tbat) of the nickel-hydrogen battery 2 detected from the detection signal of the battery temperature sensor 7 is equal to or higher than the charging completion level. The supply of electric current is stopped to complete the charging of the nickel hydrogen battery 2. Then, the process proceeds to STEP29 and returns from the "charging process" subroutine.

On the other hand, when the temporary capacity decrease flag (Fj) is set (Fj = 1), the controller 5 proceeds to STEP 23 to execute "normal charge", and then the controller 5
In STEP 24, "refresh charging" is executed for one cycle (details of refresh charging will be described later).
Then, the controller 5 counts up the refresh charge counter (Rc) in the subsequent STEP25, and the ST
Until the count value of the refresh counter (Rc) reaches a predetermined number of times in EP24, the process branches to STEP24 and "refresh charging" is repeatedly executed.

Then, when the count value of the refresh counter (Rc) reaches a predetermined number, the process proceeds to STEP 27, and the controller 5 causes the temporary capacity decrease flag (Fte
m) is reset (Ftem = 0), and in step 28, refresh charging is performed a predetermined number of times and the above-described ST of FIG.
In order to indicate that the deterioration determination of the nickel-hydrogen battery 2 in EP10 has become possible, the deterioration determination permission flag (F
j) is set (Fj = 1), and in STEP 29, the "charging process" subroutine is returned.

Next, FIG. 4 shows a flow chart of a "refresh charge processing" subroutine for executing one cycle of refresh charge, and the "refresh charge processing" subroutine is called in STEP23 of FIG.

When the "refresh charge processing" subroutine is called, the controller 5 firstly proceeds to STEP4.
In 1, the temperature (Tbat) of the nickel-hydrogen battery 2 is detected from the detection signal of the battery temperature sensor 7, and in STEP 42, it is confirmed whether or not the temperature (Tbat) of the nickel-hydrogen battery 2 is below the refresh charge start temperature (Tchst). To do.

Then, the temperature of the nickel-hydrogen battery 2 (Tba
When t) is equal to or lower than the refresh charge start temperature (Tchst), the process proceeds to STEP 43 to start supplying a constant charge current. In this way, the charging current is supplied to overcharge the nickel-hydrogen battery 2 in a state where the temperature (Tbat) of the nickel-hydrogen battery 2 is low, so that the chargeable capacity of the nickel-hydrogen battery 2 reduced by the memory effect is restored. The effect can be enhanced.

Then, the controller 5 moves to STEP44.
The rate of increase in the temperature detected by the nickel-hydrogen battery 2 (ΔT / Δ
When t) is equal to or higher than the refresh charge end level (Cend, which corresponds to the predetermined level of the present invention), STEP
In step 45, the supply of charging current is stopped, one cycle of refresh charging is completed, and in step 46, the "refresh charging process" subroutine is returned.

On the other hand, in STEP 42, the nickel hydrogen battery 2
Temperature (Tbat) is the refresh charge start temperature (Tchs
t) and the effect of recovering the chargeable capacity of the nickel-hydrogen battery 2 that has decreased due to the memory effect even if refresh charging is performed is low, the process branches to STEP50, and the controller 5 sends the battery temperature sensor 7 at STEP50.
The temperature (Tbat) of the nickel-hydrogen battery 2 is detected from the detection signal of 1 and the outside air temperature (Tamb) near the radiator 6 is detected from the temperature detected by the outside air temperature sensor 8 in STEP 51.

Then, in step 52, when the battery cooling system is in the ON state (state in which the pump 21 and the cooling fan 23 are operating), the process branches to step 60, and the controller 5 sets the temperature (Tbat) of the nickel-hydrogen battery 2 and The difference from the outside air temperature (Tamb) is the second temperature difference (Tdef2)
When the cooling effect of the nickel hydrogen 2 is low even when the cooling system is turned on, the process proceeds to STEP 61, where the battery cooling system 6 is turned off (the pump 21 and the cooling fan 23 are stopped).

In STEP 60, the difference between the temperature (Tbat) of the nickel-hydrogen battery 2 and the outside air temperature (Tamb) is larger than the second temperature difference (Tdef2), and the nickel-hydrogen battery 2 is cooled by the battery cooling system 6. When the effect is high, the process branches to STEP 55, and the controller 5 maintains the battery cooling system 6 in the ON state.

Next, when the battery cooling system 6 is in the OFF state in STEP52, the process proceeds to STEP53, and the controller 5 causes the temperature of the nickel-hydrogen battery 2 (T
bat) and the outside air temperature (Tamb) are the first temperature difference (Tde
f1 (corresponding to the predetermined temperature difference of the present invention) and the effect of cooling the nickel-hydrogen battery 2 by the battery cooling system 6 is high, the process proceeds to STEP 54 and the battery cooling system 6 is turned on.

In STEP 53, the difference between the temperature (Tbat) of the nickel-hydrogen battery 2 and the outside air temperature (Tamb) is less than or equal to the first temperature difference (Tdef1, which corresponds to the predetermined temperature difference of the present invention), When the cooling effect of the nickel hydrogen battery 2 by the battery cooling system 6 is low, the process branches to STEP 55, and the controller 5 maintains the battery cooling system 6 in the OFF state.

In this way, STEP50 to STEP5
4 and the processing of STEP 60 to STEP 61, the outside air temperature (Ta) is higher than the temperature (Tbat) of the nickel hydrogen battery 2.
mb) is lower than the first temperature difference (Tdef 1) or more and the battery cooling system 6 is turned on only when the cooling effect on the nickel hydrogen battery 2 is high, so that the controller 5 causes the pump 21 and the cooling fan. The use of 23 prevents unnecessary power consumption.

The second temperature difference (Tdef2) is slightly smaller than the first temperature difference (Tdef1) in order to prevent the battery cooling system 6 from being frequently turned on / off by providing a hysteresis. It is set to a value.

Then, in STEP 55, the temperature (Tbat) of the nickel hydrogen battery 2 is set to the refresh charge start temperature (Tchs).
Until the time becomes equal to or less than t), the nickel-hydrogen battery 2 is cooled by branching from STEP 55 to STEP 50 and by forced cooling and natural cooling by the battery cooling system 6.

Then, in STEP 55, the temperature (Tbat) of the nickel hydrogen battery 2 is set to the refresh charge start temperature (Tchs).
t) or less, the process proceeds to STEP 56, and the controller 5 turns off the battery cooling system 6 and S
Returning to TEP 43, the controller 5 starts supplying the charging current to the nickel hydrogen battery 2.

In the present embodiment, S of FIG.
With TEP44, the temperature rise rate of the nickel-hydrogen battery 2 (ΔT
/ Δt) is equal to or higher than the refresh charge end level (Cend), the refresh charge is terminated and the nickel-hydrogen battery 2 is overcharged, but the charge current is integrated in STEP 43 after the charge current supply is started. When the value reaches a predetermined charge stop value, refresh charging may be terminated and the nickel hydrogen battery 2 may be overcharged.

Further, in this embodiment, the nickel-hydrogen battery 2 is forcibly cooled by the battery cooling system 6, but the nickel-hydrogen battery 2 is cooled only by natural cooling without the battery cooling system 6. Even in such a case, the effect of the present invention can be obtained.

Further, in the present embodiment, as the cooling means of the present invention, the water cooling type battery cooling system 6 for cooling the nickel hydrogen battery 2 by circulating the refrigerant in the cooling circuit 20 is shown. By nickel hydrogen battery 2
An air-cooled battery cooling system that directly cools the battery may be used.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram of a charge / discharge control device for a nickel hydrogen battery.

FIG. 2 is a flowchart of a charging / discharging process of a nickel hydrogen battery by the charging / discharging control device shown in FIG.

FIG. 3 is a flowchart of a charging process of a nickel-hydrogen battery by the charge / discharge control device shown in FIG.

FIG. 4 is a flowchart of a refresh charge process of a nickel hydrogen battery by the charge / discharge control device shown in FIG.

[Explanation of symbols]

1 ... Nickel-hydrogen battery charge / discharge control device, 2 ... Nickel-hydrogen battery, 3 ... Battery box, 4 ... Charging circuit, 5
... controller, 6 ... battery cooling system, 7 ... battery temperature sensor, 8 ... outside air temperature sensor

Front page continuation (51) Int.Cl. ⁷ Identification code FI theme code (reference) H02J 7/00 H02J 7/00 Y (72) Inventor Takashi Ishikura 1-4-1 Chuo, Wako-shi, Saitama Stock Association In-house Honda R & D Laboratories (72) Inventor Kazuhisa Okamoto 1-4-1 Chuo Wako, Saitama Stock Company Honda R & D Laboratories F-term (reference) 2G016 CA03 CB05 CB22 CB32 CC02 CC07 CC23 CC27 CC28 CF06 5G003 AA01 BA01 CA14 CB01 EA05 EA06 EA08 FA06 GB06 GC05 5H030 AA04 BB01 FF22 FF42 5H031 KK08

Claims (5)

[Claims] 1. A nickel which has a nickel-hydrogen battery and supplies a current from the nickel-hydrogen battery to an electric load of an electric vehicle or a hybrid vehicle using the nickel-hydrogen battery as a driving power source and charges the nickel-hydrogen battery. In a charge / discharge control device for a hydrogen battery, a depth-of-discharge grasping means for grasping the depth of discharge of the nickel-hydrogen battery, and a charge for performing capacity recovery charging for recovering the chargeable capacity of the nickel-hydrogen battery to charge the nickel-hydrogen battery An integrated value of the discharge current from the start of discharge from the nickel-hydrogen battery to the load in a state where the capacity recovery charging is completed until the depth of discharge of the nickel-hydrogen battery reaches a predetermined discharge stop level. And a deterioration detection unit that determines that the nickel-hydrogen battery has deteriorated when the value becomes smaller than a predetermined integrated value. Charge and discharge control device of the nickel hydrogen battery, characterized in that. 2. A battery temperature sensor for detecting the temperature of the nickel-hydrogen battery, wherein the charging means recovers the capacity when the temperature detected by the battery temperature sensor becomes equal to or lower than a predetermined capacity recovery charge start temperature. The charging / discharging control device for a nickel-hydrogen battery according to claim 1, which is charged. 3. A cooling means for cooling the nickel-hydrogen battery, an outside air temperature sensor for detecting a temperature in the vicinity of the cooling means, a temperature detected by the battery temperature sensor is higher than the capacity recovery charging start temperature, and A cooling control means for operating the cooling means to cool the nickel-hydrogen battery only when the temperature detected by the outside air temperature sensor is lower than the temperature detected by the battery temperature sensor by a predetermined temperature difference or more. The charge / discharge control device for a nickel-hydrogen battery according to claim 2. 4. The charging means supplies a constant charging current to the nickel-hydrogen battery and starts supplying the charging current to the nickel-hydrogen battery so that an integrated value of the charging current from the start is predetermined. 4. The nickel according to any one of claims 1 to 3, wherein the capacity recovery charging is performed by repeating a process of stopping the supply of the charging current when the charging stop value becomes equal to or more than the charging stop value. Charge / discharge control device for hydrogen batteries. 5. A battery temperature detection sensor for detecting a temperature of the nickel-hydrogen battery, wherein the charging means supplies a constant charging current to the nickel-hydrogen battery and supplies a charging current to the nickel-hydrogen battery. 2. The capacity recovery charging is performed by repeating the process of starting the charging and stopping the supply of the charging current when the rate of increase in the temperature detected by the battery temperature sensor becomes equal to or higher than a predetermined level. A nickel-hydrogen battery charge / discharge control device as described.