JP2003023736A - Charger for combined battery pack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a protection circuit which is integrated with a combined battery pack. SOLUTION: A battery case 110 is provided with terminals 21A to 25A, connecting to each of cells 101 to 104. Charging voltage is individually applied to the cells 101 to 104 via charging terminals 21B to 25B from charging circuits 41 to 44, having charge control portions 10 of a charger 3 for charging the batteries. At this time, constant-current, constant-voltage control is exercised at the charge control portions 10 of the charging circuits 41 to 44, respectively.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a battery pack charging device.

[0002]

2. Description of the Related Art At present, storage batteries are widely used in all kinds of electric equipment such as power supplies for portable electric equipment such as laptop computers and mobile phones to power supplies for uninterruptible power supplies. Normally,
It is handled as an assembled battery in which a plurality of cells are connected in series according to the size of the load. As a method of charging such an assembled battery, conventionally, charging is generally performed by applying a voltage to both electrodes of the assembled battery. However, if the batteries were simply charged through the electrodes at both ends, differences in charging voltage due to variations in capacity and internal impedance appeared among the cells, and some cells were overcharged and overcharged. The unit cell may deteriorate. Therefore,
Conventionally, a protection circuit for preventing each unit cell from being overcharged and an assembled battery are inseparably housed in a battery pack, and the assembled battery is charged under the supervision of the protection circuit. I have decided. The protection circuit is provided with a circuit for monitoring the charging voltage of each unit cell, and has the function of ending the charging of all unit cells when it is detected that any unit cell is fully charged. There is. In this case, the fully charged single cells and the non-fully charged single cells coexist, resulting in an imbalance of the charge capacities between the individual single cells. For leveling, a balancer circuit that discharges a fully charged single cell or charges only an insufficiently charged single cell may be provided.

[0003]

However, in the above configuration, since the charging voltage is monitored for each unit cell, a voltage detection circuit must be provided for each unit cell, and the protection integrated with the assembled battery is required. There was a problem that the circuit became complicated. Further, when the balancer circuit is provided in addition to the voltage detection circuit for each unit cell, the protection circuit becomes more complicated. Since such a protection circuit is integrated in the battery pack, it hinders weight reduction and size reduction of the battery pack.
When the battery is replaced, it is wasted because it is discarded together with the assembled battery.

The present invention has been made in view of the above circumstances, and an object thereof is to provide an assembled battery charging device capable of simplifying a protection circuit integrated with the assembled battery as much as possible.

[0005]

According to a first aspect of the present invention, there is provided a battery pack charging apparatus for charging a battery pack in which a plurality of unit cells are connected in series, wherein a positive electrode and a negative electrode of the unit battery are provided. A plurality of pairs of charging terminals connected to each of the terminals connected to each other are provided, and the voltage between the charging terminals that form the pair and the unit cell charging circuit that charges each of the cells between the charging terminals that form the pair are detected to detect the voltage. A charging control unit for controlling the charging operation of the unit cell charging circuit is provided, and each unit cell charging circuit is characterized by being connected in parallel to a common power source.

According to a second aspect of the present invention, in the first aspect, a terminal voltage monitoring means for monitoring the voltage between the charging terminals connected to the unit cell is provided, and the terminal voltage monitoring means is provided between the charging terminals. Is characterized in that the charging operation of the unit cell charging circuit is performed under the condition that a voltage is applied to.

[0007]

According to the charging device of claim 1,
The charging control unit and the unit battery charging circuit are provided between paired charging terminals, and when the terminals connected to the positive and negative electrodes of each unit battery are connected to each charging terminal, the unit battery is charged by each unit battery charging circuit. It will be possible. Since each unit cell charging circuit is controlled by the charging control unit that detects the voltage of each unit cell, each unit cell can be individually charged to be fully charged. In this way, since each unit cell of the assembled battery is charged while being individually controlled by the unit battery charging circuit and the charge control circuit provided on the charging device side, it is not necessary to provide a protection circuit on the assembled battery side, Alternatively, even if it is provided, the configuration is extremely simple. Therefore, even when the battery pack and the protection circuit are integrated into a battery pack, the battery pack can be made smaller and lighter and can be manufactured at low cost. The fact that the battery pack can be made smaller and lighter is extremely rational considering that the battery pack is attached to the electronic device side and carried. In addition, the fact that the battery pack can be made inexpensive means that waste is reduced in consideration of the situation in which the battery pack is replaced when the life of the battery pack is exhausted.

The circuit for detecting the voltage of each unit cell is
Conventionally, it is provided on the assembled battery side, but since it is provided on the charging device side in the present invention, there is a concern that the manufacturing cost on the charging device side will increase. However, such concerns prove to be melancholy for the following reasons. That is, the individual cells that form the assembled battery are individually charged by the individual cell charging circuits and the charging control units of the charging device, and the individual cell charging circuits are connected in parallel to a common power source. It is a composition. This means that each unit cell charging circuit and charge control unit can have a common circuit configuration for each unit cell. Therefore, even when manufacturing charging devices of various specifications for various assembled batteries having different numbers of unit cells, the basic circuit can be the same and the number of combinations can be made different. For this reason,
By mass producing the basic circuit, the manufacturing cost of the entire charging device can be reduced.

According to the second aspect of the invention, the terminal voltage monitoring means is provided between the charging terminals. The voltage between charging terminals is measured by this terminal voltage monitoring means, and when the voltage is not applied, the voltage application from the charging device is prohibited,
When the voltage is applied, it is determined that the terminals of the assembled battery are connected, and the charging operation is started. As a result, if the battery pack is not connected to the charging device, the charging operation is not performed.Therefore, start charging when the charging terminal is short-circuited by a foreign object, or carelessly handle the charging terminal when voltage is applied. You can prevent touching and electric shock.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. <First Embodiment> A battery pack charging apparatus according to a first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The present embodiment relates to a charging device that charges an assembled battery of lithium ion batteries. Battery pack 1 is battery case 1
It is housed in 10, for example, four unit cells 101 to 101.
104 are connected in series. Further, the battery case 110 is provided with a battery side connector 2A, and the battery side connector 2A is provided with five terminals 21A to 25A. Terminal 21
A is connected to the positive electrode of the unit cell 101, and the terminal 25A is connected to the negative electrode of the unit cell 104. The terminal 22A is connected to the negative electrode of the unit cell 101 and the positive electrode of the unit cell 102, and the terminals 23A and 24A are similarly connected as illustrated.

The charging device 3 is provided with a charger side connector 2B which can be connected to the battery side connector 2A, and charging terminals 21B to 25B are provided therein. Also,
Corresponding to the four unit cells 101 to 104, a total of four unit cell charging circuits 41 to 44 (hereinafter simply referred to as charging circuits 41 to 44).
Is said to be provided. The charging circuits 41 to 44 are connected to the commercial power source 7 via the main relay switch 5A and the line filter 6, and the charging circuits 41 to 44 are connected in parallel to the commercial power source 7, respectively. On the other hand, on the output side of the charging circuit 41, the positive side output (+) is connected to the charging terminal 21B, and the negative side output (-) is connected to the positive side output (+) of the charging circuit 42 so that the charging terminal 22B. , The output of the other charging circuit is also in the connected state as shown in the figure, and eventually the unit cell 1
01 to 104 have a circuit configuration in which the voltages of the charging circuits 41 to 44 are individually applied.

As shown in FIG. 2, a switching regulator is used for each of the charging circuits 41 to 44, and the rectifier 8,
It is composed of an insulating type step-down chopper 9 and a charge control unit 10, and has the same structure. For example, taking the charging circuit 41 for charging the unit cell 101 as an example, the input AC power from the commercial power supply 7 is rectified by the rectifier 8, and then the duty factor of the switching element is changed by the insulating step-down chopper 9. After adjusting and stepping down, it is taken out as DC output. The charging control unit 10 detects the output voltage and output current of the insulation type step-down chopper 9 to detect the unit cell 1
The insulated step-down chopper 9 is controlled so that 01 is charged with a constant current and a constant voltage. In the initial charging, the battery is charged with a constant current, and when the battery voltage reaches a predetermined voltage, it is switched to the constant voltage charging control.

A relay switch 51 is provided in series between the charging terminal 21B and the positive electrode output of the charging circuit 41. Similarly, the relay switch 52 is also provided for the charging terminals 22B to 24B.
~ 54 are provided. The opening / closing operation of the relay switches 51 to 54 is performed by the relay 50. An FET 12A is connected in series to the relay 50, and an output port 13A of a temperature / voltage monitoring circuit 13 (hereinafter simply referred to as a monitoring circuit 13) corresponding to a terminal voltage monitoring means performs a switching operation of the FET 12A. One overvoltage detection circuit 14 is connected between the positive and negative outputs of the charging circuits 41 to 44, and the output thereof performs the switching operation of the FET 12B. In addition,
The main relay switch 5A is opened and closed by the relay 5B, and the relay 5B is controlled by the output port 13B of the monitoring circuit 13 via the FET 12C.

The monitoring circuit 13 is provided with a CPU, for example, and its input port 13C is provided with a measuring point on the charging terminal 21B side of the relay switch 51, and a voltage applied between the charging terminal 21B and the charging terminal 25B. To measure. When this voltage is 0 volt, it is determined that the battery side connector 2A is not connected, so the logical output of the output port 13A is kept at the low level (L) and the relay switch 5
Leave 1 to 54 open. When the voltage is applied, it is determined that the battery side connector 2A is connected, so the logical output of the output port 13A is set to the high level (H) and the relay switches 51 to 54 are closed. This is to determine the connection state between the charger side connector 2B and the battery side connector 2A and prevent the charging voltage from being applied to the charger side connector 2B in the non-connected state.

The input port 13D is connected to the relay switch 51.
A measurement point is provided on the output side of the charging circuit 41, and the voltage applied to the charging terminal 21B and the charging terminal 25B is measured.
When the relay switches 51 to 54 are closed,
The voltage of the battery pack 1 is applied to the input port 13D. Here, the reference voltage value is set in advance, and the output port 13B is changed by comparing the reference voltage value and the applied voltage value with the monitoring device 13. The reference voltage value is set to a voltage value at which there is no risk of inrush current due to over-discharged cells. When the applied voltage is lower than the reference voltage value, the FET 12C is kept in the OFF state and the main relay switch 5A is opened. When the applied voltage is higher than the reference voltage value, the FET 12C is turned on and the main relay switch 5A is closed.

The input port 13E is connected to, for example, a temperature measuring circuit 15 provided near the charging terminal 21B and determines whether the measured temperature value is within a predetermined temperature range. If it is within the specified temperature range, output port 13
When the output states of A and 13B are not inverted and are not within the predetermined temperature range, the output ports 13A and 13B are set to the low level (L) so that charging is impossible.

Now, the operation of the above configuration will be described.
For example, when the charging device 3 is previously connected to the commercial power source 7, the battery side connector 2A is connected to the charger side connector 2B.
Is not connected, no voltage is applied to the input port 13C, so the FET 12A is in the OFF state, so the relay 50 is not energized and the relay switches 51 to 5 are not energized.
4 remains open. Here, the battery side connector 2A
Is connected to the charger side connector 2B, the input port 13
Since the voltage of the assembled battery 1 is applied to C, the FET 12A is turned on.
The N state is entered, the relay 50 is excited, and the relay switch 5
1-54 are closed.

When the relay switches 51 to 54 are closed, the voltage of the battery pack 1 is applied to the input port 13D. If this voltage is below the reference voltage value, turn off the FET 12C.
As a result, power is not supplied to the charging circuits 41 to 44 by leaving the main relay switch 5A in the open state. When the voltage is equal to or higher than the reference voltage value, the FET 12C is turned on and the main relay switch 5A is closed to perform charging. The unit cell 1
The charging characteristics of 01 to 104 change depending on the temperature,
When the temperature value input to the input port 13E is within the preset temperature range, the charging is continued, and when the temperature value is out of the temperature range, the main relay switch 5A is opened to stop the charging.

The cells 101 to 104 are charging circuits 41 to 41, respectively.
The constant current / constant voltage charging control is individually performed by 44. As charging progresses, each cell 101-1
At 04, variation in charging capacity occurs due to difference in capacity and internal impedance. Therefore, the unit cells 101 to 104 are sequentially switched from the constant current charging control to the constant voltage charging control from the one having a predetermined voltage. Since the constant voltage control is performed, the charging current that gradually flows into the unit cell gradually decreases as the battery approaches full charge, and when the battery is fully charged, the charging current stops flowing and the charging naturally ends. For example, even if the unit cell 101 is initially fully charged and the charging current does not flow, if the other unit cells 102 to 104 are not fully charged, the charging circuits 42 to 44 do not charge them. If the unit cells 103 are fully charged next, for example, only the remaining unit cells 102 and 104 are continuously charged, and finally all the unit cells 101 to 104 are fully charged.

Further, for example, when the unit cell 103 becomes overvoltage during charging due to a control error of the charge control unit 10 of the charging circuit 43, the output signal of the overvoltage detection circuit 14 which detects the overvoltage is inverted to a high level (H). . Then, FET1
2A is turned off, and the relay switches 51 to 54 are opened in accordance with the disconnection of the relay 50, and all of the single power sources 101 to 1
The charging of 04 is interrupted. Since the overcharge detection circuit 14 monitors the double charging voltage,
The risk of overvoltage and deterioration of the entire battery pack 1 is further reduced.

As described above, according to the present embodiment, each of the unit cells 101 to 104 is provided with one charging circuit 41 to 44, and each charging circuit 41 to 44 is connected to the commercial power source 7 which is a power supply source. The cells are connected in parallel, and the individual cells 101 to 104 are individually charged by the charging circuits 41 to 44. Further, since the charging voltage is controlled by the charging control unit 10 provided in each charging circuit 41 to 44, the protection circuit on the assembled battery 1 side can be omitted. Than this,
The battery pack can be made smaller and lighter, which is especially convenient when it is attached to an electronic device and carried. In addition, since it is only necessary to replace the assembled battery when exchanging the assembled battery, it is possible to eliminate the waste of discarding the protection circuit that can be used.

The input port 13C has a charging terminal 21B.
The voltage applied between the charging terminals 25B is monitored, and when the voltage applied to the input port 13C is 0 volt, the output port 13A is set to low level (L) to close the relay switches 51 to 54. The applied voltage of 0 volt means that the charger side connector 2B and the battery side connector 2A are not connected, and in this case, the charging voltage is not applied. As a result, it is possible to prevent charging from being started in a state where the charger side connector 2B is short-circuited due to a foreign substance, or a part of the human body coming into contact with the charging terminals 21B to 25B and receiving an electric shock due to the applied voltage. Further, the voltage of the battery pack 1 connected through the input port 13D is measured, and if the voltage is equal to or lower than the reference voltage, the main relay switch 5A is opened. Therefore, when the voltage of the battery pack 1 is lower than that, a large current is temporarily applied. Can be prevented from flowing.

<Second Embodiment> A second embodiment of the present invention will be described with reference to FIG. In the present embodiment, the number of unit cells of the first embodiment is set to 7, and the same portions are denoted by the same reference numerals and duplicate description will be omitted. That is, the seven charging circuits 41 corresponding to the seven cells 101 to 107.
To 47, overvoltage detection circuit 14, relay switches 51 to 5
7, each of the cells 101 to 107 can be charged independently. As described above, if the charging circuit, the overvoltage detection circuit, and the relay switches are provided according to the number of the unit cells, the charging device can function as a protection device that does not require a protection circuit.

As described above, the charging circuits 41 to 4 which are the constituent parts of the charging device 3 of the first embodiment and the present embodiment.
7 and the overvoltage detection circuit 14 can have a common circuit configuration for each unit cell. Therefore, when manufacturing a charging device corresponding to various assembled batteries having different numbers of constituent cells, the number of combinations of these constituent parts can be changed so that the constituent parts can be replaced. Mass production can reduce the manufacturing cost of the entire charging device.

<Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings. For example, the following embodiments are also included in the technical scope of the present invention. In addition to the above, various modifications can be made without departing from the scope of the invention. (1) In the present embodiment, the case where the unit cell unit cell is a lithium ion battery is shown, but the present invention is not limited to this, and may be various storage batteries such as a lead storage battery or a nickel-cadmium secondary battery.

[Brief description of drawings]

FIG. 1 is a circuit diagram of a charging device according to a first embodiment of the present invention.

FIG. 2 is a circuit diagram of a single battery charging circuit according to the first embodiment.

FIG. 3 is a circuit diagram of a charging device according to a second embodiment.

[Explanation of symbols]

1 ... Battery pack 2A ... Battery side connector 2B ... Connector on charger side 41-44 ... Single battery charging circuit 10 ... Charge control unit 13 ... Temperature / voltage monitoring circuit

Claims (2)

[Claims] 1. A charging device for an assembled battery for charging an assembled battery comprising a plurality of unit cells connected in series, wherein a plurality of pairs of charging devices are connected to respective terminals connected to a positive electrode and a negative electrode of the unit battery. A charging device that has a terminal and detects the voltage between the unit battery charging circuit that charges each of the unit cells between the pair of charging terminals and the pair of charging terminals and controls the charging operation of the unit battery charging circuit. And a control unit, wherein each of the unit battery charging circuits is connected in parallel to a common power source. 2. A unit voltage monitoring unit for monitoring a voltage between charging terminals connected to the unit cell is provided, and the unit cell charging is performed on condition that a voltage is applied between the charging terminals by the terminal voltage monitoring unit. The battery pack charging apparatus according to claim 1, wherein the charging operation of the circuit is performed.