JPH10164765A - Battery driver, and battery managing device, and controller for external apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a battery from overdischarge or the like and extend the life of the battery, by receiving the discharge inhibition signal sent out by the discharge inhibition state of the battery, and inhibiting the operation of an external apparatus. SOLUTION: A discharge inhibition judging means 52 outputs a discharge inhibition signal a to a power line 30 through an external communication circuit 38 when a charge judging part 50 judges it to be in charge of when the battery voltage V during charge drops to a specified value or under, and a demodulation circuit 24 demodulates the discharge inhibition signal a. A CPU 26 judges the situation of the battery 18 by the demodulated discharge inhibition signal A, and controls a bridge circuit 28, based on an external signal B. The CPU 26 controls the drive voltage and current of a motor 10 by changing the duty of the bridge circuit 28 continuously, based on the external signal B at normal operation, and zeros the duty of the bridge circuit 28 if it should inhibit the discharge, based on the discharge inhibition signal A, and stops the supply of current and voltage to the motor 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery driving device for driving an external device using a battery provided with a battery management device for monitoring a charge / discharge state as a power supply.

[0002]

2. Description of the Related Art Nickel-cadmium batteries (Ni-Cd
For a rechargeable battery (secondary battery) such as a battery, it is necessary to select an optimal charging method depending on various conditions such as the type of battery, discharge state, ambient temperature, number of times of charge and discharge, and the like. In addition, it is necessary to monitor the amount of discharge, determine the remaining capacity as accurately as possible, and notify the user.

[0003] A CP for managing the charging and discharging of such a battery.
A battery management device has been proposed in which a U (microprocessor) is provided in a battery so that the battery can be used under optimum use conditions (for example, Japanese Patent Application Laid-Open No. Hei 6-81425).

Conventionally, when a battery with a battery management device is used by being connected to an external device, the controller of the external device determines whether the battery has been discharged. For example, when the output voltage of the battery falls below a specified value, the discharge is stopped.

[0005]

In this case, since the state of the battery cannot be accurately determined on the external device side, other battery conditions cannot be used as the data for judging discharge prohibition. For example, the remaining capacity of the battery and the minimum discharge voltage vary depending on the usage history of the battery, and the battery temperature also varies depending on the charging method and the ambient temperature. Since the temperature and the like cannot be detected, there is a problem that such unique data different for each battery cannot be used.

For this reason, there has been a problem that it is not possible to accurately determine when to prohibit discharge. Therefore, there is also a problem that the battery is over-discharged to damage the battery and shorten its life.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the foregoing circumstances, and accurately determines a discharge prohibition time in consideration of conditions unique to each battery, protects the battery from overdischarge and the like, and provides a battery life. It is an object of the present invention to provide an electric drive device capable of increasing the length of the electric drive.

Another object of the present invention is to provide a battery management device and a controller for an external device used in the battery driving device.

[0009]

According to the present invention, it is an object of the present invention to provide a battery driving device for driving an external device by using a battery with a battery management device for monitoring a charging / discharging state as a power source. Discharge prohibition determining means for determining and outputting a discharge prohibition signal, and signal sending means for outputting the discharge prohibition signal to a controller of the external device,
The controller of the external device includes a demodulation circuit that receives the discharge inhibition signal, and an external device CPU that inhibits operation of the external device because the demodulation circuit receives the discharge inhibition signal. This is achieved by a battery drive.

[0010] Here, it is desirable that the discharge prohibition signal be sent on a power line for supplying the battery output to an external device. The discharge prohibition determining means may be configured to detect that the remaining battery capacity, the battery voltage, and the battery temperature of the battery are outside the specified ranges, and output a discharge prohibition signal. In addition, it is preferable to output a discharge prohibition signal also during charging.

In the battery management device used in the battery driving device, a battery CPU for determining whether the battery is in a discharge-prohibited state is provided.
And a signal transmitting means for transmitting a discharge prohibition signal to the control unit of the external device when the battery CPU determines the discharge prohibition state.

Further, a controller of an external device used in the battery driving device includes a demodulation circuit for receiving a discharge inhibition signal sent from the battery management device, and an operation of the external device when the demodulation circuit receives the discharge inhibition signal. And a CPU for an external device that prohibits the operation.

[0013]

FIG. 1 is an overall schematic view of an embodiment of the present invention.
FIG. 2 is a block diagram mainly showing the functions of the CPU.

1 and 2, reference numeral 10 denotes a motor, 12
Is a controller, 14 is a battery management device, and 16 is a charger. The battery management device 14 includes a battery 18. The alternating current supplied from the alternating current power supply 20 is rectified by the charger 16 and passes through the diode 22 in a predetermined charging mode.
Charge 8.

The controller 12 supplies a predetermined current and voltage to the motor 10 using the battery 18 as a power source, and
Drive 0. For example, when the motor 10 is a DC motor, the controller 12 may be of a chopper type that controls on / off of the output voltage of the battery 18 at a predetermined duty.

The controller 12 has a demodulation circuit 24, an external device CPU 26, and a semiconductor bridge circuit 28, as shown in FIG. The demodulation circuit 24 demodulates the discharge inhibition signal a sent from the battery management device 14 on the power line 30 as described later. The CPU 26 determines the state of the battery 18 based on the demodulated discharge inhibition signal A, and controls the bridge circuit 28 based on the external signal B.

That is, the CPU 26 controls the drive voltage and current of the motor 10 by continuously changing the duty of the bridge circuit 28 based on the external signal B during normal operation. If the discharge is to be prohibited based on the demodulated discharge prohibition signal A, the CPU 26 sets the duty of the bridge circuit 28 to 0. That is, the supply of the voltage and current to the motor 10 is stopped, and the fact is displayed on the display device 32.

Reference numeral 34 denotes a battery CPU (microprocessor). Its function will be described later. Reference numeral 36 denotes a power supply circuit (FIG. 2), and the voltage of the battery 18 (for example, 24 V)
To a predetermined voltage (for example, 5 V).

Reference numeral 38 denotes an external communication circuit (communication interface) as signal transmission means, 40 denotes current detection means, 42
Denotes voltage detecting means. The external communication circuit 38 inputs and outputs data to and from the controller 12, the charger 16, and other external devices. For example, the external communication circuit 38
4 outputs a signal indicating the result of determining the state of the battery 18 to the controller 12 via the power line 30.

The current detector 40 detects the charge / discharge current I of the battery 18 and converts it into a voltage that can be input to the CPU.
4 is input. The voltage detector 40 converts the voltage of the positive electrode voltage V of the battery 18 and inputs the converted voltage to the CPU 34. The voltage detector 40 monitors the voltage V even during discharging.

Reference numeral 44 denotes a battery temperature detecting section comprising a thermistor provided on the battery 18. More specifically, a current change of the thermistor 44, which changes according to the battery temperature θ, is amplified and converted into a voltage and input to the CPU 34.

In FIG. 2, reference numeral 46 denotes an EEPROM (Electrically
Erasable / Programmable Read Only Memory). E
The EPROM 46 stores various data used in the calculation by the CPU 34, for example, the type of the battery 18 and its characteristic data, a capacity reduction characteristic due to the battery temperature θ, and also stores data during the calculation and a remaining capacity as a calculation result.

Next, the function of the CPU 34 will be described. CPU
When an activation command comes from the controller 12 or the charger 16, the initialization is performed. Although the CPU 34 operates by software, its function is shown in a block diagram in FIG.

The CPU 34 first determines whether or not charging is being performed by the charger 16 using the charging determination unit 50. This determination is to convert the voltage V _c of the power lines 30A between the diode 22 and the charger 16 to a voltage suitable for CPU and input to CPU 34, and during charging if the voltage V _c is a positive predetermined voltage or more to decide.

Reference numeral 52 denotes discharge prohibition determining means, which outputs a discharge prohibition signal a when the charging determination section 50 determines that charging is being performed or when the battery voltage V during discharging drops below a predetermined value. This discharge prohibition signal a is output from the external communication circuit 38 (communication I /
The signal is output to the power line 30 via F). During charging, the CPU 34 calculates the amount of charge by the remaining capacity calculating unit 54 (FIG. 2). That is, the charge amount is determined by the product (ampere hour) of the current I detected by the battery current detection unit 40 and the charging time.

On the other hand, the CPU 34 obtains electric power from the product of the voltage and the current during charging in the electric power integrating section 56, and corrects the charged amount according to the magnitude of the electric power. This correction is performed in consideration of the fact that the charging efficiency changes depending on the magnitude of the charging current and the charging method, and is performed by the remaining capacity correction unit 58. The result is E
The data is stored in the EPROM 46 and sent to the controller 12 via the communication interface 38 as necessary.
It is displayed on the display device 32.

The CPU 34 determines whether or not the battery is discharging from the flow direction of the battery current I.
U34 calculates the amount of discharge. That is, the amount of discharge (ampere hours) is obtained by integrating time with the discharge current detected by the battery current detection unit 40. The CPU 34 converts this into the EEPROM4
The current value of the remaining capacity is obtained by subtracting from the remaining capacity stored in 6.

It is a matter of course that the remaining capacity correction unit 58 may add a correction based on a change in power to the present value. The corrected remaining capacity is stored in the EEPROM 46.
The result is sent to the controller 12 via the communication interface 38 and displayed on the display device 32.

When a state where neither charging nor discharging is performed, that is, a standing state continues for a predetermined time (for example, 30 minutes), the CPU
34 determines that the vehicle is being left, and enters a low power consumption mode. In this mode, peripheral devices such as the current detection unit 40, the voltage detection unit 42, the battery temperature detection unit (thermistor 44), and the display device 32 are stopped. The CPU 34 is driven by a low-speed clock pulse.

In this low power consumption mode, the communication interface 38 is in operation, and
When an external interrupt command from a charging or discharging command comes from the controller, the normal operation mode is entered and peripheral devices are started.

If a predetermined time (for example, 30 minutes) elapses without an external interrupt, the self-discharge amount is calculated.
PU 34 returns to the normal operation mode. The peripheral devices activated at this time include a battery temperature detecting unit 44 and a battery voltage detecting unit 42.
And the EEPROM 46. At this time, the CPU 34 operates by a high-speed clock pulse.

In this state, the CPU 34 calculates the amount of self-discharge. For this calculation, the decrease rate characteristic of the remaining capacity with respect to the battery temperature T stored in the EEPROM 46 is used.

In the CPU 34, the battery temperature θ is obtained by the temperature measuring section 60 based on the signal output from the thermistor 44, and the remaining capacity reduction rate is obtained from the stored remaining capacity characteristics. Then, the remaining capacity is corrected by integrating this remaining capacity reduction rate with the remaining capacity stored in the EEPROM 46 before the predetermined time. This result is stored in the EEPROM 46 and returns to the low power consumption mode again.

The discharge prohibition determining means 52 of the CPU 34 sends a discharge prohibition signal a to the controller 12 when the battery temperature θ detected by the battery temperature detector (thermistor 44) during charging and discharging falls outside a specified range. Also, when the battery voltage V falls below a predetermined value during the discharging or when the remaining capacity is out of the set range, the discharging prohibition signal a is similarly sent to the controller 12. Upon receiving the discharge prohibition signal a, the demodulation circuit 24 of the controller 12 demodulates the signal and sends it to the external device CPU 26 to stop the discharge.

In this embodiment, since the discharge prohibition signal a is carried on the power line 30, the number of connectors for the signal lines between the battery management device 14 and the controller 12 is reduced. Transmission and reception of signals between the charger 16 and the battery management device 14 may be similarly performed via the power line 30A. The present invention can of course be applied to an external device other than the motor 10, for example, a driving device such as a heater or a lamp.

[0036]

As described above, according to the first aspect of the present invention, it is determined whether or not the battery management device is in a dischargeable state, and a discharge prohibition signal is output. This signal is demodulated by the controller of the external device. Since the operation of the external device is stopped, discharge can be prohibited at an appropriate time in consideration of conditions such as the history and temperature of each battery. For this reason, the battery is not damaged by overdischarge or the like, and the battery life can be extended.

Here, if the discharge prohibition signal is sent to the controller of the external device via a power line for supplying power from the battery to the external device, the signal of the connector between the battery management device and the external device can be obtained. The number of terminals can be reduced (claim 2).

It is preferable that the discharge prohibition signal is output when it is determined that one of the remaining capacity of the battery, the battery voltage and the battery temperature is out of the specified range. In addition to the above, it is also possible to detect whether or not the battery is being charged and to output a discharge prohibition signal during charging.

According to the fifth aspect of the present invention, there is provided a battery management device used for implementing this device. According to the invention of claim 6, a controller for an external device used for implementing this apparatus is obtained.

[Brief description of the drawings]

FIG. 1 is an overall schematic diagram of an embodiment of the present invention.

FIG. 2 is a block diagram mainly showing functions of a CPU;

[Explanation of symbols]

Reference Signs List 10 Motor as external device 12 Controller 14 Battery management device 16 Charger 18 Battery 24 Demodulation circuit 26 CPU for external device 26 Bridge circuit 30, 30A Power line 32 Display device 34 Battery side CPU 38 External communication circuit as signal transmission means ( Communication I /
F) 40 Battery current detector 42 Battery voltage detector 44 Thermistor as battery temperature detector 46 Memory (EEPROM) 50 Charge determination unit 52 Discharge prohibition determination means 58 Remaining capacity correction unit 60 Temperature measurement unit

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H02J 7/04 H02J 7/04 AL

Claims (6)

[Claims] 1. A battery driving device for driving an external device by using a battery with a battery management device for monitoring a charge / discharge state as a power supply, wherein the battery management device determines a battery discharge prohibition state and outputs a discharge prohibition signal. And a signal transmission unit that outputs the discharge prohibition signal to a controller of the external device. The controller of the external device includes a demodulation circuit that receives the discharge prohibition signal, and the demodulation circuit discharges the signal. An external device CPU that prohibits the operation of the external device upon receiving a prohibition signal. 2. The battery driving device according to claim 1, wherein the signal transmission unit transmits the discharge inhibition signal through a power line that supplies an output of the battery to an external device. 3. The discharge prohibition judging means judges that one of the remaining capacity of the battery, the battery voltage, and the battery temperature is out of a specified range, and outputs a discharge prohibition signal.
Or the battery drive device of 2. 4. The battery driving device according to claim 3, wherein said discharge prohibition determining means further detects a charge state of said battery and outputs a discharge prohibition signal. 5. A battery management device for use in the battery driving device according to claim 1, wherein a battery CPU for determining a battery prohibition state and a controller of an external device when the battery CPU determines a discharge prohibition state. A battery management device comprising: signal transmission means for transmitting a discharge prohibition signal. 6. A controller for an external device used in the battery driving device according to claim 1, wherein the demodulation circuit receives a discharge inhibition signal sent from the battery management device, and the demodulation circuit receives the discharge inhibition signal. And a CPU for an external device for inhibiting the operation of the external device.