JP3384251B2 - Battery charge / discharge control circuit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery mounted on an electric vehicle or the like, which is charged by a charger or discharged by a power controller. The present invention relates to a charge / discharge control circuit for a battery (hereinafter, simply referred to as a “charge / discharge control circuit”) used in such a case. 2. Description of the Related Art There is a battery mounted on an electric vehicle or the like that is detachable from an electric vehicle or the like by storing the battery in a case with a handle. This battery unit is detached from the electric vehicle or the like and connected to a charger. When charging is completed, the battery unit is mounted on the electric vehicle or the like and connected to the power controller. A charging or discharging terminal is provided on an outer surface of the battery unit. Since these terminals are exposed, there is a possibility that a short circuit may occur if a metal piece or the like touches the terminals. Therefore, there is an improvement in which a charge / discharge control circuit including a relay or the like is attached to a battery so that the terminal is turned on for the first time when the terminal is connected to a charger or a power controller. FIG. 12 is a circuit diagram showing a case where a battery unit is connected to a charger in such a conventional charge / discharge control circuit. Hereinafter, description will be made based on this drawing. A conventional charge / discharge control circuit 80 includes a charge / discharge terminal 82, a control terminal 84, a common terminal 88 connected to a negative electrode 86m of a battery 86, and a charge / discharge terminal 82 and a positive electrode 86p of the battery 86. A normally open contact 90 inserted in
An electromagnetic coil 92 inserted between the charge / discharge terminal 82 and the control terminal 84 to close the normally open contact 90 when a predetermined voltage is applied between the charge / discharge terminal 82 and the control terminal 84; I have. The normally open contact 90 and the electromagnetic coil 92 are one electromagnetic relay 93. The charge / discharge control circuit 80 and the battery 86 are housed in a battery unit 94. The normally open contact 90 is connected to the positive electrode 86p of the battery 86 and the charge / discharge terminal 8
2, the charge / discharge terminal 82 and the control terminal 8
4 and any two of the common terminals 88 at the same time,
There is no potential difference between them. A charger 96 converts an AC voltage obtained from a commercial power outlet 98 into a DC charging voltage, and outputs this charging voltage from a positive terminal 96p and a negative terminal 96m.
The charging terminal 100 is connected to the positive terminal 96p, and the control terminal 102 and the common terminal 104 are connected to the negative terminal 96m. Charger 96, charging terminal 100, control terminal 1
02 and the common terminal 104 are housed in the charger unit 106. The battery unit 94 is connected to the charger unit 1
06, the charging / discharging terminal 82 and the charging terminal 100,
The control terminal 84 is connected to the control terminal 102, and the common terminal 88 is connected to the common terminal 104. Then, the battery 86
Alternatively, when a predetermined voltage is applied to the electromagnetic coil 92 from the charger 96, the normally open contact 90 is closed. Therefore, when the charge / discharge terminal 82 and the positive electrode 86p of the battery 86 conduct, the battery 96 is charged from the charger 96. [0007] However, the conventional charge / discharge control circuit 80 has the following problem when the battery 86 tends to be over-discharged. In this case, although the electromagnetic relay 93 operates simultaneously with the start of charging, an excessive charging current flows to the battery 86. Then, the charger 96
Immediately drops, and this causes the electromagnetic relay 93 to return. Here, when the electromagnetic relay 93 returns, the charging current stops flowing and the charging voltage increases. Then, the electromagnetic relay 93 operates again, and the above operation is repeated. As described above, when the battery 86 tends to be over-discharged, chattering occurs in the electromagnetic relay 93, so that not only the normally-open contact 92 is damaged but also charging becomes impossible. If the battery 86 is to be used at, for example, 24 V, the electromagnetic relay 93 is of 24 V specification. Generally, the operating voltage (voltage that can be turned on) of an electromagnetic relay is about ± 20% of a standard value. Therefore, if the voltage is 19 V or less, the electromagnetic relay 93 cannot be turned on, and charging cannot be performed. This voltage is an open-circuit voltage in a completely discharged state, which reaches immediately if left undischarged. Further, in the charging completion period, the electromagnetic relay 93 may be damaged by applying an overvoltage to the electromagnetic relay 93. The overvoltage referred to here is specifically the standard value of 20
%, For example, 29.0 V or more in the case of a 24 V specification. In the 24V specification, application of 30V or more is usually performed. SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide a charging / discharging method that does not cause a short circuit even when a terminal on the outer surface of a battery unit is touched and that can be charged even when the battery is likely to be overdischarged. It is to provide a control circuit. A charge / discharge control circuit according to the present invention comprises a charge terminal, a discharge terminal, a control terminal, a common terminal connected to a second pole of a battery, and the charge terminal. A first electrode of the battery, a diode interposed between the discharge terminal and the first pole of the battery, and a diode interposed between the discharge terminal and the first pole of the battery. A contact control inserted between a pole or a second pole and the control terminal and closing the normally open contact when a predetermined voltage is applied between the first pole or the second pole and the control terminal. Part, between the first electrode of the battery and the discharge terminal
And a set resistor . The first electrode may be a positive electrode and the second electrode may be a negative electrode. Conversely, the first electrode may be a negative electrode and the second electrode may be a positive electrode. It is preferable that the normally open contact and the contact control unit are electromagnetic relays in terms of performance and cost. When nothing is connected to the charge / discharge control circuit, even if any two of the charge terminal, the discharge terminal, the control terminal and the common terminal are touched at the same time, there is no potential difference that allows a large current to flow therethrough. This is because the charging terminal is disconnected from the first electrode of the battery by the diode, the discharging terminal is disconnected by the normally open contact, and the control terminal is disconnected by the internal resistance of the contact control unit. Even when the battery is about to be overdischarged, normal charging can be performed regardless of the discharge state of the battery as long as a forward voltage is applied to the diode. In addition, discharge terminals that are not used during charging are detected by voltage detection.
, The voltage detection terminal can be omitted. FIG. 1 to FIG. 5 are the premise of the present invention.
That indicates a first reference example of the charge and discharge control circuit, FIG. 1 is a circuit diagram showing a case of connecting the battery unit to the charger, Figure 2 is a circuit diagram showing a case of connecting the battery unit to the power controller, Fig. 3 Is an external view showing the internal structure of the battery unit, FIG. 4 is an external view when the battery unit is connected to a charger, and FIG. 5 is an external view when the battery unit is connected to a power controller. Hereinafter, description will be made based on these drawings. However, the same parts as those in FIG. The charge / discharge control circuit 10 includes a charge terminal 12,
A discharging terminal 14, a control terminal 16, a common terminal 18 connected to the negative electrode 86m of the battery 86, a diode 20 connected to the charging terminal 12 for conducting only the charging current to the battery 86, and a positive electrode of the diode 20 and the battery 86 86p, a normally open contact 24 interposed between the discharge terminal 14 and the positive electrode 86p of the battery 86, a positive electrode 86p of the battery 86 and the control terminal 1
6 and an electromagnetic coil 26 as a contact control unit that opens the normally closed contact 22 and closes the normally open contact 24 when a predetermined voltage is applied between the positive electrode 86p and the control terminal 16. , Is provided. The normally closed contact 22 may be omitted. In this case, the diode 20 is connected to the positive electrode 8 of the battery 86.
Connect directly to 6p. Normally closed contact 22 and normally open contact 24
May be constituted by transfer contacts. The normally closed contact 22, the normally open contact 24 and the electromagnetic coil 26 are one electromagnetic relay 28. The charge / discharge control circuit 10 and the battery 86 are housed in the battery unit 30. When nothing is connected to the charge / discharge control circuit 10, the charge terminal 12, the discharge terminal 14, the control terminal 16, and the common terminal 18 are exposed from the battery unit 30. Here, even if any two of these terminals are touched at the same time, no potential difference occurs between them. This is because the charge terminal 12 is disconnected from the positive electrode 86p of the battery 86 by the diode 20, the discharge terminal 14 is disconnected by the normally open contact 24, and the control terminal 16 is disconnected by the internal resistance of the electromagnetic coil 26. The battery 86 includes two batteries 861 and 862 (FIG. 3), and is, for example, a sealed lead battery. Next, the charger Uni the battery unit 30
The connection to the socket 106 will be described with reference to FIGS. When the battery unit 30 is fitted to the charger unit 106, the charging terminals 12 and 100,
The common terminal 18 and the common terminal 104 are connected respectively.
The connection structure between the terminals may be any structure such as a slide contact type or a connector type. Thereby, the diode 20
Is applied, the charging terminal 12 and the positive electrode 86p of the battery 86 conduct through the diode 20 and the normally closed contact 22. Thus, the battery 86 is charged from the charger 96. Also, when the battery 86 is about to be over-discharged, the electromagnetic relay is not operated with the output voltage of the battery 86 or the charging voltage of the charger 96 unlike the conventional case, and therefore, regardless of the discharge state of the battery 86. Charging can be performed normally. Next, a case where the battery unit 30 is connected to the power controller 32 will be described with reference to FIGS. The power controller 32 is provided, for example, in the electric tricycle 34 and supplies the power of the battery 86 to the load 36. The discharge terminal 38 is connected to the positive terminal 32p of the power controller 32. Negative electrode terminal 3 of power controller 32
A control terminal 42 and a common terminal 44 are connected to 2 m via a main switch 40.
The power controller 32, the discharge terminal 38, the control terminal 42, and the common terminal 44 are housed in a power controller unit 46. Here, when the battery unit 30 is fitted to the power controller unit 46, the discharge terminals 14 and 38, the control terminals 16 and 42, the common terminals 18 and 4
4 are respectively connected. The connection structure between the terminals may be any structure such as a slide contact type or a connector type. Subsequently, when the main switch 40 of the electric tricycle 34 is closed, the battery 86 is connected to the electromagnetic coil 26 via the common terminals 18 and 44, the main switch 40 and the control terminals 16 and 42.
Is applied. Then, the electromagnetic coil 26 opens the normally closed contact 22 and closes the normally open contact 24, whereby the discharge terminal 14 and the positive electrode 86 p of the battery 86 conduct through the normally open contact 24. Thus, discharging from the battery 86 to the power controller 32 is performed. [0017] FIGS. 6 to 8 show a second reference example of the premise becomes the charge and discharge control circuit of the present invention, FIG. 6 is a circuit diagram showing a case of connecting the battery unit to the charger, 7 a battery unit FIG. 8 is an equivalent circuit diagram showing a case where the battery unit is connected to a charger, and FIG. 8 is a circuit diagram showing a case where the battery unit is connected to a power controller. Hereinafter, description will be made based on these drawings. However, the same parts as those in FIGS. 1 to 5 are denoted by the same reference numerals, and redundant description will be omitted. The charge / discharge control circuit 50 of the present embodiment has a first reference
In addition to the configuration of the charge / discharge control circuit 10 (FIG. 1) of the present invention, a thermistor 52 as a temperature detecting element for converting the temperature of the battery 86 into an electric signal, and a temperature detecting terminal for outputting the electric signal converted by the thermistor 52 54, a resistor 56 connected to the positive electrode 86p of the battery 86, and a voltage detection terminal 58 connected to the resistor 56. of course,
Only one of the thermistor 52 and the temperature detection terminal 54 and the resistor 56 and the voltage detection terminal 58 may be provided. The charger 60 used in this embodiment is a first charger.
In addition to the configuration of the charger 96 (FIG. 1) used in the reference example ,
A temperature signal input terminal 601 and a voltage signal input terminal 602 are provided. The charger unit 106 is provided with a temperature detection terminal 603 connected to the temperature signal input terminal 601 and a voltage detection terminal 604 connected to the voltage signal input terminal 602. As shown in FIG. 7, the charger 60 includes a CPU 621, an AC / DC converter 622,
Switching circuit 623 and resistor 62 for voltage detection
4,625, capacitor 626 and diode 627
And a resistor 628 and a capacitor 629 for temperature detection. Next, the battery unit 30 is
Will be described with reference to FIGS. 6 and 7. When the battery unit 30 is fitted to the charger unit 106, the charging terminals 12 and 100, the common terminal 1
8 and the common terminal 104, the voltage detection terminal 58 and the voltage detection terminal 604, and the temperature detection terminal 54 and the temperature detection terminal 603, respectively. As a result, a forward voltage is applied to the diode 20, so that the charging terminal 12 and the positive electrode 86p of the battery 86 conduct through the diode 20 and the normally closed contact 22. Thus, the battery 86
Is charged. Further, the temperature of the battery 86 is detected as the resistance value of the thermistor 52 and the temperature detection terminal 5
4, and is output to the charger 60. The output voltage of the battery 86 is determined by the resistor 56 and the voltage detection terminal 58,
Output to the charger 60 via 604. CPU62
1 executes a charge control according to a program by outputting a control signal to the switching circuit 623 based on information on the temperature and the output voltage of the battery 86. Charge / discharge control circuit 10 of the first reference example (FIG. 1)
Then, since the output voltage of the battery 86 is detected via the charging terminals 12 and 100, the influence of errors such as a voltage drop due to a charging current at a wiring (conductor resistance) and a terminal (contact resistance), a forward voltage of the diode 20, and the like. Receive. In contrast, the book
In the charge / discharge control circuit 50 of the reference example , since almost no current flows through the resistor 56 and the voltage detection terminals 58 and 604, the influence of the above-described error is not exerted. Next, a case where the battery unit 30 is connected to the power controller 64 will be described with reference to FIG.
The power controller 64 used in this embodiment has a temperature signal input terminal 641 in addition to the configuration of the power controller 32 (FIG. 2) used in the first embodiment . The power controller unit 46 has a temperature detection terminal 642 connected to the temperature signal input terminal 641. Here, when the battery unit 30 is fitted to the power controller unit 46, the discharge terminal 14 and the discharge terminal 38, and the control terminal 16 and the control terminal 4
2. The common terminal 18 is connected to the common terminal 44, and the temperature detection terminal 54 is connected to the temperature detection terminal 642. Subsequently, when the main switch 40 is closed, the output voltage of the battery 86 is applied to the electromagnetic coil 26 via the common terminals 18 and 44, the main switch 40, and the control terminals 16 and 42. Then, the electromagnetic coil 26 opens the normally closed contact 22 and closes the normally open contact 24, whereby the discharge terminal 14 and the positive electrode 86 p of the battery 86 conduct through the normally open contact 24. Thus, discharging from the battery 86 to the power controller 32 is performed. Further, the temperature of the battery 86 is detected as the resistance value of the thermistor 52, and the temperature detection terminals 54, 6
The signal is output to the power controller 64 through the power controller 42. A CPU (not shown) built in the power controller 64 executes discharge control according to a program based on information on the temperature of the battery 86. 9 to 11 show an embodiment of a charge / discharge control circuit according to the present invention. FIG. 9 is a circuit diagram showing a case where a battery unit is connected to a charger. FIG. FIG. 1 is an equivalent circuit diagram showing the case of connection.
1 is a circuit diagram showing a case where a battery unit is connected to a power controller. Hereinafter, description will be made based on these drawings. However, the same parts as those in FIGS. 6 to 8 are denoted by the same reference numerals, and redundant description will be omitted. The charge / discharge control circuit 70 according to the present embodiment is characterized in that a resistor 72 is provided between the positive electrode 86p of the battery 86 and the discharge terminal 14. That is, the charge / discharge control circuit 70 is obtained by removing the resistor 56 and the voltage detection terminal 58 (FIG. 6) from the charge / discharge control circuit 50 (FIG. 6) of the second reference example and adding a resistor 72. . According to the charge / discharge control circuit 70, the charge / discharge control circuit 50
The number of terminals is reduced by one by using the discharge terminals 14 not used during charging for voltage detection. Next, the battery unit 30 is
9 is different from the second reference example in the case where
This will be described with reference to FIG. When the battery unit 30 is fitted to the charger unit 106, the charging terminal 12 and the charging terminal 100, the common terminal 18 and the common terminal 104, the discharging terminal 14 and the voltage detecting terminal 604, and the temperature detecting terminal 54 and the temperature detecting terminal 603 are respectively connected. Is done. Thus, the battery 86 is charged from the charger 60. The output voltage of the battery 86 is output to the charger 60 via the resistor 72, the discharge terminal 14, and the voltage detection terminal 604. Next, the case where the battery unit 30 is connected to the power controller 64 will be described with reference to FIG. When the battery unit 30 is fitted to the power controller unit 46, the discharge terminal 14 and the discharge terminal 38, the control terminal 16 and the control terminal 42, and the common terminal 18
And the common terminal 44, the temperature detection terminal 54 and the temperature detection terminal 64
2 are connected respectively. At this time, the resistor 72 and the discharge terminals 14 and 38 are supplied from the battery 86 to the voltage controller 64.
The resistance of the resistor 72 is set so that no leak current flows through the resistor 72. Subsequently, when the main switch 40 is closed, the output voltage of the battery 86 is applied to the electromagnetic coil 26 via the common terminals 18 and 44, the main switch 40, and the control terminals 16 and 42. Then, the electromagnetic coil 26 opens the normally closed contact 22 and closes the normally open contact 24, whereby the discharge terminal 14 and the positive electrode 8 of the battery 86 are closed.
6p is conducted through the normally open contact 24. Thus,
Discharge is performed from the battery 86 to the power controller 32. According to the charge / discharge control circuit of the present invention ,
When nothing is connected to the charge / discharge control circuit, the charge terminal is disconnected from the first pole of the battery by the diode, the discharge terminal is disconnected by the normally open contact, and the control terminal is disconnected from the first pole of the battery by the internal resistance of the contact control unit. A short circuit can be prevented by touching any two of the terminals at the same time. In addition, since the electromagnetic relay is not operated with the output voltage of the battery or the charging voltage of the charger as in the conventional case, even if the battery is about to be over-discharged, as long as the forward voltage is applied to the diode, the battery is not charged. Normal charging can be performed regardless of the discharging state, and inconvenience caused by application of overvoltage to the electromagnetic relay during the charging completion period can be avoided. [0028] Further , by providing a resistor interposed between the first pole of the battery and the discharge terminal, a voltage detection terminal is provided by using a discharge terminal not used during charging for voltage detection. Therefore, an accurate battery output voltage that is not affected by the charging current can be detected.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a first reference of a charge / discharge control circuit which is a premise of the present invention.
FIG. 4 is a circuit diagram showing a case where a battery unit is connected to a charger in an example . FIG. 2 is a first reference of a charge / discharge control circuit which is a premise of the present invention.
FIG. 4 is a circuit diagram showing a case where a battery unit is connected to a power controller in an example . FIG. 3 is a first reference of a charge / discharge control circuit which is a premise of the present invention.
In an example , it is an outline view showing an internal structure of a battery unit. FIG. 4 is a first reference of a charge / discharge control circuit which is a premise of the present invention.
In an example , it is an outline view when a battery unit is connected to a charger. FIG. 5 is a first reference of a charge / discharge control circuit which is a premise of the present invention.
In an example , it is an outline view when a battery unit is connected to a power controller. FIG. 6 is a second reference of a charge / discharge control circuit which is a premise of the present invention.
FIG. 4 is a circuit diagram showing a case where a battery unit is connected to a charger in an example . FIG. 7 is a second reference of a charge / discharge control circuit which is a premise of the present invention.
In an example , it is an equivalent circuit diagram showing a case where a battery unit is connected to a charger. FIG. 8 is a second reference of a charge / discharge control circuit which is a premise of the present invention.
FIG. 4 is a circuit diagram showing a case where a battery unit is connected to a power controller in an example . FIG. 9 is a circuit diagram showing a case where a battery unit is connected to a charger in one embodiment of the charge / discharge control circuit according to the present invention. FIG. 10 is an equivalent circuit diagram showing a case where a battery unit is connected to a charger in one embodiment of the charge / discharge control circuit according to the present invention. FIG. 11 is a circuit diagram showing a case where a battery unit is connected to a power controller in one embodiment of the charge / discharge control circuit according to the present invention. FIG. 12 is a circuit diagram showing a case where a battery unit is connected to a charger in a conventional charge / discharge control circuit. [Description of Signs] 10, 50, 70 Charge / discharge control circuit 12 Charging terminal 14 Discharging terminal 16 Control terminal 18 Common terminal 20 Diode 22 Normally closed contact 24 Normally open contact 26 Electromagnetic coil (contact control unit) 52 Thermistor (Temperature detecting element) 54) Temperature detection terminals 56, 72 Resistor 58 Voltage detection terminal 86 Battery 86m Battery negative electrode 86p Battery positive electrode

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H02J 7/00 B60L 11/18 H01M 10/44

Claims (1)

(57) [Claim 1] A charging terminal, a discharging terminal, a control terminal,
A common terminal connected to the second pole of the battery, a diode interposed between the charging terminal and the first pole of the battery to conduct only the charging current for the battery, and the discharge terminal and the first pole of the battery. A normally open contact inserted between
The normally open contact is inserted between the first pole or the second pole of the battery and the control terminal, and when a predetermined voltage is applied between the first pole or the second pole and the control terminal. A contact control unit to be closed, between the first electrode of the battery and the discharge terminal
A charge / discharge control circuit for a battery , comprising: an interposed resistor .