JPH06215801A - Charging/discharging device for storage battery - Google Patents

Abstract

PURPOSE:To prevent an excessive charging current or discharging current from flowing in a storage battery at the time of a mode transition in a charging/ discharging device switching the current control, voltage control, and power control modes for the charge/discharge control of the storage battery. CONSTITUTION:The constant-current, constant-voltage, and constant-power modes are switched by a control amplifier circuit 7 and a control circuit 6 to charge a storage battery BAT with a charger 4 or to discharge it with a discharger 5, and the charging/discharging current is limited by current limiting circuits 711, 712. The current immediately before a mode transition is stored in a memory circuit 716 to limit the current, the current stored prior to the mode transition is used as a current limit set value, and the occurrence of an excessive current is prevented at the time of the mode transition.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging / discharging device for a storage battery, which is used for various tests and a power source of the storage battery, and more particularly to a charging / discharging control device.

[0002]

2. Description of the Related Art FIG. 4 shows a conventional storage battery charging / discharging device for a storage battery test. The main circuit rectifies and smoothes the AC power of the AC power supply 1 with the rectifier 2 and the smoothing capacitor 3, obtains a DC output with current / voltage / power control by the charger 4, and charges the storage battery BAT to be tested with this DC output. . The discharger 5 serves as a load on the storage battery BAT, and
Performs direct current absorption with voltage / power control.

The control device includes a control circuit 6 for controlling the charging / discharging current / voltage / power amount by pulse control or analog control for on / off control of control elements (transistors etc.) of the charger 4 and the discharger 5, A control amplifier circuit 7 for obtaining a control signal for this control and detectors 8 and 9 for detecting the charging / discharging current / voltage of the storage battery BAT are provided.

As a mode for charging / discharging the storage battery BAT, generally, (1) constant current charging ... charging the storage battery with a constant current (2) constant power charging ... charging the storage battery with constant power (3) constant voltage charging ... storage battery voltage (4) Constant current discharge: Discharge the storage battery with a constant current (5) Constant power discharge: Discharge the storage battery with a constant power (6) Constant voltage discharge: Six types of discharge with a constant storage battery voltage Then, the control device performs automatic control according to each mode.

For the constant voltage charge / discharge control, the control amplifier circuit 7 is used.
The relay 7 ₁ is closed and the voltage control amplifier 7 ₂ obtains a voltage control signal by comparing the detection signal of the voltage detector 9 and the set value of the voltage setter 7 ₃ , and the control circuit 6 outputs the charging output of the charger 4. Control or automatically control the discharge output of the discharger 5.

For constant current charge / discharge control, the relay 7 ₄ is closed, and the current control signal is obtained by comparing the detection signal of the current detector 8 and the set value of the current setter 7 _{6 in} the current control amplifier 7 ₅ . The circuit 6 automatically controls the output of the charger 4 or the discharger 5.

For constant power charge / discharge control, a power detection signal is obtained by multiplying the detected current and voltage by a multiplier 7 ₇ .
The relay 7 ₈ is closed, the power control amplifier 7 ₉ compares the power detection signal with the set value of the power setter 7 ₁₀ to obtain a power control signal, and the control circuit 6 automatically controls the output of the charger 4 or the discharger 5. To do.

The amplifier 7 ₁₁ obtains a current limit signal according to the deviation between the set value of the limit current setter 7 ₁₂ and the detected current of the current detector 8, and the control circuit 6 charges and discharges the charger 4 or the discharger 5. Limit current control.

The set value of the setter 7 ₁₂ is set to the rated current value or the maximum allowable value of the charger 4 or the discharger 5 to protect them, and the charge / discharge current of the storage battery BAT is set by the setter 7 ₆ . These controlled amplifiers 7 ₁₁ and setters 7 ₁₂ form a current limiting circuit.

[0010]

Since a recent storage battery is expected to undergo severe charge / discharge when used as a power source of an electric vehicle, various conventional test modes are randomly combined for the test. To be taken care of.

For example, one test content includes switching from constant power charging to constant voltage charging and switching to constant current discharging.

There is a problem that an excessive current flows through the storage battery when the test mode is switched as described above.

For example, when the mode is shifted from constant power charging to constant voltage charging, the constant power charging power P ₁ is

[0014]

## EQU1 ## P ₁ = charging current i × storage battery voltage v, and current i = i ₁ at the time of transition to constant voltage charging, voltage v
= V ₁ and the set value E ₁ for constant voltage charging is

[0015]

[Equation 2] If E ₁ = v ₁ , the current i ₁ at the time of transition does not change, but it is difficult to estimate the voltage v ₁ under this condition. For this reason,

[0016]

[Equation 3] When E ₁ > v ₁ , the charging current i is calculated from i ₁

[0017]

## EQU4 ## i = (E ₁ −v ₁ ) / r However, r increases to the internal resistance of the storage battery.

This increase in current becomes remarkable in proportion to the difference between the voltages E ₁ and v _1, and its maximum value rises to the set value of the setter 7 ₁₂ .

However, since the set value of the setter 7 ₁₂ does not correspond to the rating of the storage battery and is set according to the device capacity, when testing a storage battery of a small capacity with a large device, the storage battery exceeds the allowable current. Current flows, which deteriorates the test accuracy and deteriorates the storage battery.

An object of the present invention is to provide a charging / discharging device which prevents an excessive charging current or discharging current from flowing through the storage battery when the mode is changed.

[0021]

In order to solve the above-mentioned problems, the present invention provides a charging / discharging device for switching between current control mode, voltage control mode, and power control mode for charging / discharging control of a storage battery. A storage circuit for storing a charge or discharge current of the storage battery and a current limiting circuit for limiting the current stored in the storage circuit at the time of the mode transition are provided.

[0022]

The current immediately before the transition to the mode is stored in the memory circuit at the time of the mode transition, and is limited to the stored current during the mode transition to prevent the overcurrent of the storage battery at the mode transition.

[0023]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention. 4 is different from FIG. 4 in that the control amplifier circuit 7 is provided with circuit elements 7 _{14 to} 7 ₁₆ .

The relay 7 ₁₄ is opened is closed current detection signal constantly uptake, mode transition period only. The changeover switch 7 ₁₅ is normally set to the setter 7 ₁₂ side, and is changed over to the memory circuit 7 ₁₆ side only during the mode transition period.

The memory circuit 7 ₁₆ receives the charge / discharge current detection signal of the storage battery BAT through the relay 7 _{14 at} all times, stores and updates the current detection signal, and opens the relay 7 ₁₄ during the mode transition period to open the mode. The current detection signal immediately before the shift is kept stored, and the set value to the amplifier 7 ₁₁ is continuously given as the current detection signal immediately before the mode shift in place of the set value of the setter 7 ₁₂ by switching the changeover switch 7 ₁₆ .

In the present embodiment, for example, when the storage battery BAT is switched from the constant power charging mode to the constant voltage charging mode, constant power charging limited to the current limit value set in the setter 7 ₁₂ is performed during the constant power charging period. The current value during charging is stored and updated in the storage circuit 7 ₁₆ .

When the mode is changed from the constant power charging to the constant voltage charging, the relay 7 ₁₄ is opened, and the charging current value immediately before that is held as the stored value of the storage circuit 7 ₁₆ . Then, the changeover switch 7 ₁₅ is switched to the side of the memory circuit 7 ₁₆ so that the current limit value becomes a value stored in the memory circuit 7 _16, and the current limit for constant voltage charging is performed with this value.

Due to this current limitation, the voltage E ₁ during constant voltage charging becomes higher than the voltage v ₁ during constant power charging E ₁ >> v ₁
However, the current limit value can prevent the charging current from rapidly increasing.

After the transition to the constant voltage charging mode is completed, the storage battery B is controlled by the voltage control by the voltage control amplifier 7 _2.
When the AT voltage rises and enters a stable state where there is no risk of overcurrent, the changeover switch 7 ₁₅ is returned to the setting device 7 ₁₂ side, the relay 7 ₁₄ is also closed, and thereafter the current limit is set by the set value 7 _12. Constant voltage charging is carried out and current memory update is started.

When shifting between other charging / discharging modes, the current limiting value is limited to the current value of the mode before shifting by the same action to shift to a new mode to prevent the occurrence of overcurrent.

FIG. 2 shows a circuit diagram of the memory circuit. This circuit constitutes the sample-and-hold circuit with an operational amplifier OP, the charge voltage of the capacitor C is changed according to the voltage of the current detection signal, after the circuit of the relay 7 ₁₄ continues to output the charging voltage of the capacitor C as a memory voltage .

FIG. 3 shows another current limiting circuit diagram. The memory circuit 7 ₁₆ has a set voltage V _S of the setter 7 ₁₂ and a current detection signal Vf.
The voltage obtained by adding and is stored in the capacitor C and updated, and this output is closed by the relay 7 _{17 in} place of the switching relay 7 ₁₅ when the mode is changed to be one addition input of the adder 7 ₁₈ , and the output of the setter 7 ₁₂ . The value is added together with the set value V _S and the detected current signal Vf and is input to the amplifier 7 ₁₁ .

In the embodiment, the current detection signal is stored once before the mode is changed, and the same effect can be obtained.

The present invention is not limited to the case of performing constant current control / constant voltage control / constant power control of charge / discharge in each mode of a storage battery, but is also applicable to a device for program control of current / voltage / power in each mode. Of course, it can be applied.

Further, the present invention shows the case of a charging / discharging device for which a storage battery has been tested, but can be applied to mode switching control of a storage battery used as a power source such as a storage battery used as a power source of an electric vehicle.

[0036]

As described above, according to the present invention, when the charging / discharging of the storage battery is switched to each mode of the current / voltage / power control, the current value immediately before the mode transition is stored and the memory value is stored at the time of the mode transition. Since charging or discharging is limited to the current value to be performed, there is an effect that an overcurrent of the storage battery current at the time of mode transition is prevented, an adverse effect on the storage battery is eliminated, and a stable mode transition is achieved.

[Brief description of drawings]

FIG. 1 is a device configuration diagram showing an embodiment of the present invention.

FIG. 2 is a memory circuit diagram of an embodiment.

FIG. 3 is another current limiting circuit diagram.

FIG. 4 is a configuration diagram of a conventional device.

[Explanation of symbols]

BAT ... Storage battery 4 ... Charger 5 ... Discharger 6 ... Control circuit 7 ... Control amplifier circuit 7 ₂ ... Voltage control amplifier 7 ₅ ... Current control amplifier 7 ₇ ... Multiplier 7 ₉ ... Power control amplifier 7 ₁₁ ... Amplifier 7 ₁₂ ... Limiting current setting device 7 ₁₄ ... Relay 7 ₁₅ ... Changeover switch 7 ₁₆ ... Memory circuit

Claims (1)

[Claims] 1. A charging / discharging device for switching between current control mode, voltage control mode and power control mode for charging / discharging control of a storage battery, comprising: a storage circuit for storing the charging or discharging current of the storage battery immediately before the mode transition; A charging / discharging device for a storage battery, comprising: a current limiting circuit that limits the current stored in the storage circuit.