JP3583626B2 - Charge / discharge device - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a charge / discharge device for charging and discharging a secondary battery, and more particularly to an improvement in a voltage detection method for a secondary battery during charging and discharging.
[0002]
[Prior art]
Various types of secondary batteries are known, such as a lead battery, a nickel-cadmium battery, a lithium-ion battery, and a nickel-metal hydride battery. The charge / discharge device is used to acquire various characteristic data such as charge characteristics, discharge characteristics, charge / discharge repetition characteristics, etc. necessary for research and development of these various secondary batteries and ensuring product reliability. .
[0003]
FIG. 3 is a configuration example of a conventional charge / discharge device. This charge / discharge device includes a charge / discharge unit 1 and a control unit 20. In the charging / discharging unit 1, a charging DC power supply 3 and a discharging circuit 4 are switched by a switch (SW) 5 and connected to test terminals 6 and 7. The test terminal 6 is a positive electrode (+), and the test terminal 7 is a negative electrode (-). A secondary battery 9 is connected between the test terminals 6 and 7 via a load line 8.
[0004]
In the control unit 20, the input terminal of the voltage measurement circuit 10 is connected to the measurement terminals 12, 13. The measurement terminal 12 is a positive electrode (+), and the measurement terminal 13 is a negative electrode (-). A secondary battery 9 is connected between the measurement terminals 12 and 13 via a voltage detection line 14. An output terminal of the voltage measurement circuit 10 is connected to a voltage monitoring circuit 21, and a control signal is output from the voltage monitoring circuit 21 to the charge / discharge unit 1.
[0005]
In the above configuration, the basic operation of the charge / discharge device is roughly as follows. When charging the secondary battery 9, the DC power supply 3 is connected to the test terminals 6 and 7 by switching the switch SW5 to the charging side. Charging of the secondary battery 9 is started according to a predetermined method. The charging voltage of the secondary battery 9 is detected by the voltage measuring circuit 10 and reported to the voltage monitoring circuit 21 one by one. The voltage monitoring circuit 21 outputs a charge end signal to the charge / discharge unit 1 when the detected charging voltage has reached a predetermined voltage or when the charging time has reached a predetermined time. Thereby, the charging / discharging unit 1 disconnects the connection between the DC power supply 3 and the test terminals 6 and 7 and ends the operation of charging the secondary battery 9.
[0006]
When the secondary battery 9 is to be discharged, the switch SW5 is switched to the discharge side, and the discharge circuit 4 is connected to the test terminals 6 and 7. Discharge of the secondary battery 9 is started according to a predetermined method. The discharge voltage of the secondary battery 9 is detected one by one by the voltage measurement circuit 10 and reported to the voltage monitoring circuit 21. The voltage monitoring circuit 21 outputs a discharge end signal to the charge / discharge unit 1 when the detected discharge voltage reaches a predetermined voltage or when the discharge time reaches a predetermined time. Thereby, the charge / discharge unit 1 disconnects the connection between the discharge circuit 4 and the test terminals 6 and 7 and ends the discharge operation of the secondary battery 9. In addition, the control unit 20 detects the battery current in the charging / discharging control process as described above and reflects the detected battery current in the control operation.
[0007]
The secondary battery 9 to be tested is not always located in the vicinity of the charging / discharging device and is often located at a considerable distance, so that the load line 8 and the voltage detection line 14 are A length (one line is several meters to 20 meters) is prepared. In order to reduce the measurement error, a low-resistance copper wire having the following resistance is selected and used for the load line 8 and the voltage detection line 14.
[0008]
(1) Regarding the load line 8: In the charge / discharge device, the voltage drop Vd of the load line 8 is a problem. This voltage drop Vd is usually set to about Vd = 0 V to 2 V in line reciprocation. And a maximum charge-discharge current I _max of the voltage drop Vd and discharge device, the resistance value R _L of the load line 8 is selected to satisfy the relationship of R _L <Vd ÷ I _max.
[0009]
(2) Regarding the voltage detection line 14: If the resistance value of the voltage detection line 14 is R _LS , the input impedance of the voltage measurement circuit 10 is R _IN , and the maximum charge / discharge current of the charge / discharge device is V _max , the voltage measurement error is , Equation (1).
Voltage measurement error = R _LS (V _max / (R _IN + R _LS )) (1)
The resistance value R _LS of the voltage detection line 14 is selected such that the influence on the voltage measurement error is sufficiently small. Usually, assuming that R _IN > 1 MΩ, the resistance value R _LS is several Ω or less.
[0010]
[Problems to be solved by the invention]
By the way, the connection between the voltage detection line 14 and the secondary battery 9 depends on a clip, a connector, or the like. However, the connection may be disconnected for some reason, and if there is a poor connection, the state is equivalent to the disconnection. . When such a connection abnormality between the voltage detection line 14 and the secondary battery 9 occurs, the charge voltage and the discharge voltage cannot be measured, so that the control unit 2 cannot control the charge / discharge unit 1 and overcharge or overdischarge occurs. Then, the secondary battery 9 may be damaged.
[0011]
In the conventional charging / discharging device, the voltage measuring circuit 10 sets a lower limit value / upper limit value of the measured voltage, and measures can be taken such as stopping the test when a voltage exceeding the limited voltage is measured. ing. However, this measure is for the case where the connection between the voltage detection line 14 and the secondary battery 9 is normal, and does not function when the connection is abnormal, so a measure is desired.
[0012]
The present invention has been made to solve such a problem, and an object of the present invention is to stop charging / discharging operation and stop overcharging or overcharging when a connection abnormality occurs between a voltage detection line and a secondary battery. An object of the present invention is to provide a charging / discharging device including means capable of preventing the occurrence of a discharge beforehand and reporting the occurrence of a connection abnormality to the outside.
[0015]
The charging / discharging device according to the first aspect of the present invention includes a charging / discharging unit configured to charge / discharge a secondary battery connected to a load line, and a voltage detected by a voltage detection line connected to the secondary battery. A charge / discharge device including a control unit that monitors a charge state / discharge state of a secondary battery and controls a charge / discharge operation performed by the charge / discharge unit, wherein the charge / discharge device flows between the load line and the voltage detection line. A current loop is formed using a dedicated power supply, and a detection circuit that detects an abnormality in connection between a voltage detection line and the secondary battery by detecting opening of the current loop, the control unit includes: When the detection circuit detects a connection abnormality, the operation of the charge / discharge unit is stopped.
[0016]
In the charge / discharge device according to the second aspect of the present invention, in the charge / discharge device according to the first aspect , when the detection circuit detects a connection abnormality, the control unit notifies the outside of the connection abnormality. Features.
[0019]
(Action)
According to the first aspect of the invention, when a connection abnormality occurs, the detection circuit detects the abnormality and the control unit stops the operation of the charge / discharge unit. This can prevent the secondary battery from being overcharged or overdischarged.
According to the invention described in claim 2 , when a connection error occurs, the control unit notifies that the connection error has occurred and the measurement has been stopped. Thereby, when a connection abnormality occurs, appropriate measures such as inspection and repair of the abnormal part can be quickly taken.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a configuration example of a charge / discharge device that is a premise of the embodiment . 1, the same components as those of the conventional example (FIG. 3) are denoted by the same reference numerals and names.
[0021]
In FIG. 1, the load line 8 and the voltage detection line 14 are connected by resistors Ra and Rb, respectively. The load line 8 indicates a connection line from the switching output terminal of the SW 5 to the secondary battery 9, and the voltage detection line 14 indicates a connection line from the measurement input terminal of the voltage measurement circuit 10 to the secondary battery 9. In the charging / discharging device which is a premise of the embodiment , the charging / discharging unit 1 and the control unit 2 are arranged adjacent to each other, so that the resistors Ra and Rb are connected to the test terminals 6 and 7 from the switching output terminal of SW5 in the device. It is provided between the middle of the load line 8 and the middle of the voltage detection line 14 from the measurement input terminal of the voltage measurement circuit 10 to the measurement terminals 12 and 13. Of course, a configuration in which the test terminal 6 and the measurement terminal 12 are connected by a resistor Ra, and the test terminal 7 and the measurement terminal 13 are connected by a resistor Rb may be employed.
[0022]
A disconnection detection circuit 15 is provided between the load line 8 and the voltage detection line 14, that is, between the charge / discharge unit 1 and the control unit 2. The negative terminal of the power supply E1 is connected to a voltage detection line 14 connected to the positive measuring terminal 12. The positive terminal of the power supply E1 is connected to one end of the resistor R1, and the other end of the resistor R1 is connected to the cathode of the light emitting diode of the photocoupler PC1. The anode of the light emitting diode of the photocoupler PC1 is connected to the load line 8 connected to the positive test terminal 6. Then, the collector and the emitter of the phototransistor of the photocoupler PC1 are connected to the voltage monitoring circuit 11.
[0023]
The negative terminal of the power supply E2 is connected to a voltage detection line 14 connected to the negative measuring terminal 13. The positive terminal of the power supply E2 is connected to one end of the resistor R2, and the other end of the resistor R2 is connected to the cathode of the light emitting diode of the photocoupler PC2. The anode of the light emitting diode of the photocoupler PC2 is connected to a load line 8 connected to the negative test terminal 7. The collector and the emitter of the phototransistor of the photocoupler PC2 are connected to the voltage monitoring circuit 11. Then, the voltage monitoring circuit 11 outputs an alarm signal indicating a connection abnormality from the output states of the photocouplers PC1 and PC2.
[0025]
Next, the operation of the charging / discharging device as a premise of the embodiment will be described with reference to FIG. In FIG. 1, both ends of a secondary battery 9 are connected to a measurement input terminal of a voltage measurement circuit 10 via a voltage detection line 14 and resistors Ra and Rb.
Therefore, for example, when the connection between the voltage detection line 14 and the secondary battery 9 is disconnected for some reason, the voltage across the secondary battery 9 is applied to the measurement input terminal of the voltage measurement circuit 10 via the resistors Ra and Rb. Therefore, the voltage of the secondary battery 9 can be measured by the voltage detection circuit 10. Thereby, the control unit 2 can control the charging / discharging operation of the charging / discharging unit 1 based on the detection voltage of the voltage detection circuit 10, so that it is possible to prevent the secondary battery 9 from being overcharged or overdischarged.
[0026]
At this time, in order to reduce a measurement error in a normal state in a state where the resistors Ra and Rb are connected, the resistance value R of the resistors Ra and Rb is determined by setting the resistance value of the voltage detection line 14 to R _LS , the input impedance if _{R iN,} selected so as to satisfy the relation R iN »R»R _LS.
When the connection between the voltage detection line 14 and the secondary battery 9 is disconnected, the measurement is performed including the voltage drop due to the resistance value _RL of the load line 8. The battery voltage of the secondary battery 9 becomes lower than the detection voltage by the charging current I × the resistance value _RL . This is the measurement error during charging. In the constant voltage charging, since the charging current I decreases, the error decreases as the charging time increases. At the time of discharging in a detached state, the battery voltage of the secondary battery 9 becomes higher than the detection voltage by the charging current I × the resistance value _RL . This is the measurement error at the time of discharge.
[0027]
As described above, the measurement can be continued even when the connection is disconnected, but there is a measurement error. By simply adding the resistors Ra and Rb, the user continues the measurement without knowing the occurrence of the connection abnormality, so that data with reduced accuracy is obtained. Therefore, it is necessary to take measures for notifying the user of the occurrence of the connection abnormality and entrusting the decision whether to continue or stop the measurement. This means is realized by the entirety of the disconnection detection circuit 15 and the voltage monitoring circuit 11.
[0028]
At the time of normal connection, the circuit of the power supply E1, the resistor R1, and the photocoupler PC1 can form a loop current from the positive load line 8 → the positive voltage detection line 14 → the positive load line 8, so that the phototransistor of the photocoupler PC1 is Turn on. Similarly, the circuit of the power supply E2, the resistor R2 and the photocoupler PC2 can form a loop current from the negative load line 8 → the negative voltage detection line 14 → the negative load line 8, and the phototransistor of the photocoupler PC2 is turned on. The output states of the photocouplers PC1 and PC2 are given to the voltage monitoring circuit 11, and it is detected that the connection is normal. Since this loop current does not flow through the secondary battery 9, it does not affect the charging / discharging operation / measurement. However, since the loop current causes a voltage drop in each of the load line 8 and the voltage detection line 14, the voltage measurement circuit 10 includes an error in the measured value.
[0029]
This measurement error is obtained by assuming that the resistance value of the load line 8 is R _L , the resistance value of the voltage detection line 14 is R _LS , the resistance value of the resistor R1 (R2) is R _E , and the voltage of the power supply E1 (E2) is E. For example, R _LS × E / ( _RL + _RE + R _LS ) becomes a measurement error. Therefore, the measurement error is reduced by selecting R _E ≫R _LS .
Next, when a connection abnormality occurs, the above-described current loop is opened, so that both the phototransistors of the photocouplers PC1 and PC2 are turned off, and the occurrence of the connection abnormality is detected by the voltage monitoring circuit 11, and the outside is detected. An alarm signal is output. Based on this alarm signal, an error display (lamp), an error message display on a personal computer, and the like can be performed.
[0030]
This can prevent the user from continuing the test without noticing the occurrence of the abnormality. The user can also take measures to continue or stop the test. In other words, in applications where measurement accuracy is strictly required, measures can be taken to stop the measurement and repair abnormalities.In applications where measurement accuracy is not so important, the test cannot be continued and the data cannot be collected. You can select the measures to be taken.
[0031]
Figure 2 is a configuration example of a charging and discharging device of the embodiment type state corresponding to claim 1. Discharge device implementation form of this, the premise becomes rechargeable device of the embodiment resistor shown in (see FIG. 1) Ra, with the only detection circuit 15 off omit Rb, voltage monitoring In addition to the output of the alarm signal, the circuit 11 has a function of stopping the operation of the charging / discharging unit 1 in response to detection of disconnection.
The correspondence between the above configuration and the claims is as follows. The charging / discharging unit 1 corresponds to the charging / discharging unit. The control unit corresponds to the control unit. A load line 8 corresponds to the load line. The secondary battery 9 corresponds to the secondary battery. The voltage detection line 14 corresponds to the voltage detection line. The resistors Ra and Rb correspond to the resistors. The detachment detection circuit 15 corresponds to the detection circuit.
[0032]
The implementation form of this, as described in the rechargeable device which is a premise of the embodiment (see FIG. 1), a reduction in measurement accuracy due to the addition of detachment detecting circuit 15, the resistance value R of the resistor R1 (R2) _E is selected to be larger than the resistance value R _LS of the voltage detection line 14 in an effort to reduce it.
[0033]
When a connection abnormality occurs, the above-described current loop is opened, so that the phototransistors of the photocouplers PC1 and PC2 are both turned off. Then, in response to the occurrence of the connection abnormality, the voltage monitoring circuit 11 sends an operation stop command to the charge / discharge unit 1 to stop the charge / discharge operation. This can prevent the secondary battery from being overcharged or overdischarged. In addition, the voltage monitoring circuit 11 outputs an alarm signal to the outside to display an error display (lamp) or an error message on a personal computer, and notifies the user that the measurement has been stopped due to the occurrence of a connection error. It can promptly prompt you to take appropriate measures such as inspection and repair of abnormal points.
[0035]
【The invention's effect】
According to the invention described in 請 Motomeko 1, if the connection abnormality occurs, detects it, it is possible to stop the operation of the discharge portion, prevent the secondary battery is overcharged or over-discharge from occurring it can.
[0036]
According to the second aspect of the present invention, when a connection error occurs, it is possible to notify that the connection has occurred and the measurement has been stopped. Action can be taken promptly.
[Brief description of the drawings]
FIG. 1 is a configuration example of a charge / discharge device that is a premise of an embodiment .
2 is a configuration example of a charging and discharging device implementation forms.
FIG. 3 is a configuration example of a conventional charge / discharge device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Charge / discharge part 2 Control part 3 DC power supply 4 Discharge circuit 5 Switch (SW)
6, 7 Test terminal 8 Load line 9 Secondary battery 10 Voltage measurement circuit 11 Voltage monitoring circuit 12, 13 Measurement terminal 14 Voltage detection line 15 Detachment detection circuit Ra, Rb Resistors E1, E2 Power supplies R1, R2 Resistors PC1, PC2 Photo coupler

Claims (2)

A charge / discharge unit that performs charging / discharging of the secondary battery connected to the load line, and monitors a charge state / discharge state of the secondary battery based on a voltage detected by a voltage detection line connected to the secondary battery, A control unit that controls the charging / discharging operation performed by the charging / discharging unit.
A current loop flowing between the load line and the voltage detection line is formed using a dedicated power supply, and by detecting the opening of the current loop, a connection abnormality between the voltage detection line and the secondary battery is detected. It has a detection circuit to detect,
The charge / discharge device, wherein the control unit stops the operation of the charge / discharge unit when the detection circuit detects a connection abnormality. The charge / discharge device according to claim 1,
Before SL control unit when said detecting circuit detects an abnormal connection, connection error discharge apparatus characterized by notifying to the outside.

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