JP2010063198A - Power supply unit and method for charging power storage means - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply unit and a method for charging power storage means, enabling highly efficiently full charging by switching the charging from constant current to constant voltage while avoiding overcharging for each of the power storage means even if variation exists in the charging state of each of the power storage means. <P>SOLUTION: The power supply unit includes: semiconductor elements T which are connected in parallel for each of the plurality of power storage means and can be energized only in the charging direction; a voltage detecting means for detecting a terminal voltage Vi of each of the power storage means in charging; and a control means for controlling a resistance value of the semiconductor elements T based on the detection value from the voltage detecting means. The control means 12 maintains the semiconductor elements T in an OFF state from the start of charging to perform charging control, then performs first control for controlling the resistance value of each of the semiconductor elements connected to the power storage means in parallel so as to successively perform constant voltage charging for the power storage means in which the detection value of the voltage detecting means has reached a predetermined voltage set in advance, and performs second control for controlling a charging current from an external power supply 13 so as to apply a predetermined voltage to the final power storage means in which the detection value has reached the predetermined voltage. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply device and a method for charging power storage means, and in particular, a power supply device that performs charging with a plurality of power storage means connected in series, and charging of the power storage means that charges a plurality of power storage means using the power supply device Regarding the method.

As a conventional power supply device, for example, a voltage equalization device for a power storage device disclosed in Patent Document 1 and a power storage system including the device are known.
In this power storage system, as shown in FIG. 5, the power storage device is configured by further connecting a plurality of module batteries configured by connecting a plurality of cells (secondary batteries) 21 </ b> A and 21 </ b> B in series. .
The voltage equalization device 20 of the power storage device is connected in parallel to the plurality of cells (secondary batteries) 21A and 21B in a one-to-one correspondence.
A voltage dividing resistor R3 and VR are connected in parallel with the cell 21A, and a midpoint of the voltage dividing resistor is connected to a reference terminal R of the shunt regulator 23.
The anode terminal A of the shunt regulator 23 is connected to the negative side of the cell 21A, and the cathode terminal K is connected to the positive side of the cell 21A via series resistors R1 and R2.
The middle points of the resistors R1 and R2 are connected to the base terminal B of the collector-grounded bipolar transistor 24, the emitter terminal E is connected to the plus side of the cell 21A, and the collector terminal C is connected to the minus side of the cell 21A.

In the voltage equalization device 20 of the power storage device, when charging progresses and the terminal voltage of the cell 21A reaches the full charge voltage, the full charge voltage is divided by the voltage dividing resistors R3 and VR and applied to the reference terminal R of the shunt regulator 23. Applied.
The shunt regulator 23 becomes conductive, and a current flows from the cathode terminal K to the anode terminal A.
As a result, a voltage difference is generated between both ends of the resistor R1, a potential difference is generated between the emitter terminal E and the base terminal B of the bipolar transistor 24, and the bipolar transistor 24, which has been turned off until now, is activated.
As a result, a bypass current path Q through the bipolar transistor 24 is formed, and the charging current flowing through the bypass current path Q is supplied to the cell 21B.
Since the charging current flows via the bypass current path Q when each cell reaches the full charge voltage, overcharging can be prevented in the cell that has reached the full charge state, and The cells that have not reached can be continuously charged. As a result, even if there is a variation in the state of charge of the cells constituting the power storage device, it is possible to ensure that all the cells are fully charged.
JP 2003-289629 A

The conventional technique disclosed in Patent Document 1 only includes an overcharge prevention bypass circuit connected in parallel to each cell, and even if there is a variation in the charge state of each cell, the constant current charge to the constant voltage. The charging control to switch to charging is not performed.
Further, in the conventional technique, each cell having a variation in the charging state can be charged with the full charge voltage. However, in the voltage equalizing apparatus, the resistance value of the bipolar transistor is changed to change the current value of the bypass current path Q. Therefore, the loss for each voltage equalizing device is large.

  The present invention has been made in view of the above-described problems, and the object of the present invention is to avoid constant overcharge for each power storage means even when there is a variation in the charge state of each power storage means, and from constant current charging to constant voltage. In addition to enabling efficient full charging by switching to charging, the present invention provides a power supply device and a method for charging power storage means that can reduce power loss due to loss during charging as compared with the prior art.

In order to achieve the above object, the present invention provides a power supply apparatus that performs charging by supplying a charging current from an external power supply in a state where a plurality of power storage means are connected in series, and is connected in parallel for each power storage means, and only in the charging direction. A semiconductor element that can be energized, a voltage detection means that detects a terminal voltage of each power storage means during charging, and a control means that controls a resistance value of the semiconductor element based on a detection value from the voltage detection means, The control unit performs charge control by maintaining the semiconductor element in an off state from the start of the charging process, and then stores power in which the detection value of the voltage detection unit reaches a preset predetermined voltage in the power storage unit. The first control is performed to control the resistance values of the semiconductor elements connected in parallel to the power storage means so that constant voltage charging is sequentially performed on the means, and the last power storage means that has reached a predetermined voltage is applied to the last power storage means. And performing a second control that controls the charging current from the external power source so that a voltage is applied.
Note that the power storage means here may mean a rechargeable secondary battery and a capacitor, or may mean a battery module composed of a plurality of secondary batteries.

According to the power supply device and the charging method of the power storage device according to the present invention, the plurality of power storage devices are charged in a state of being connected in series.
The control means performs charge control by maintaining the semiconductor element in the off state from the start of the charging process.
The terminal voltage is detected by the voltage detection means of each power storage means at the time of charging, and when the power storage means reaches a predetermined voltage in order, the control means is connected in parallel to the power storage means that has reached the predetermined voltage so as to perform constant voltage charging sequentially. First control for controlling the resistance values of the semiconductor elements is performed.
Furthermore, the control means performs a second control for controlling the charging current from the external power supply so that the predetermined voltage is applied to the last power storage means that has reached the predetermined voltage.
In the present invention, since two types of control such as the first control and the second control are performed, even if there is a variation in the charging state of each power storage unit, overcharging is avoided for each power storage unit and constant current charging is performed. Switching to constant voltage charging enables efficient full charging.

  According to the present invention, in the power supply device described above, the first control is configured to control a resistance value of the semiconductor element and generate a predetermined voltage in the semiconductor element, whereby the terminal voltage of the power storage unit is set to the predetermined voltage. The second control is controlled by the first control in a state in which the semiconductor element connected in parallel with the power storage unit that has finally reached a predetermined voltage is maintained in an off state. The terminal voltage of the power storage means that has finally reached a predetermined voltage using the semiconductor element may be controlled to be maintained at a predetermined voltage.

In this case, the resistance value of the semiconductor element connected in parallel with the power storage means that receives the first control is controlled, and the terminal voltage of the power storage means is generated by generating a predetermined voltage in the semiconductor element by controlling the resistance value of the semiconductor element. Is maintained at a predetermined voltage.
The current passing through the semiconductor element is used for charging other power storage means that has not reached the predetermined voltage, and loss due to energization occurs in the semiconductor element.
Further, the energization of the semiconductor element connected in parallel with the power storage means that receives the second control is cut off, and the terminal voltage of the power storage means is maintained at a predetermined voltage by constant voltage charging in a state where the energization of the semiconductor element is cut off.
Therefore, since the energization of the semiconductor element connected in parallel with the power storage means that receives the second control is cut off, no loss occurs in the semiconductor element, and almost no power loss occurs in the charging of the power storage means that receives the second control. Does not occur.
In addition, since the last power storage means that has reached a predetermined voltage maintains a predetermined voltage by constant voltage charging without generating a loss, compared with a conventional power supply device that generates a loss for each charging of each power storage means Shortening the charging time can be expected.

According to the present invention, in the power supply device described above, the control unit may end the charge control of all the power storage units after a predetermined time has elapsed after starting the second control.
In this case, since charging control of all the power storage means is finished when a predetermined time has elapsed after the start of the second control, charging of each power storage means can be finished simultaneously in a fully charged state.

According to the present invention, in the power supply device described above, the control unit determines whether or not the power storage unit that has reached a predetermined voltage is the last power storage unit, and if it is determined that the power storage unit is not the last power storage unit, Each semiconductor element may be controlled to start the second control when the control is started and it is determined as the last power storage means.
In this case, the control means can determine, for example, whether the power storage means that has reached the predetermined voltage is the power storage means that has finally reached the predetermined voltage using software. Compared with the configuration provided with the element to be determined, the circuit configuration of the power supply device can be simplified.

In the present invention, in the above power supply apparatus, the power storage unit may be a lithium ion battery, and the predetermined voltage may be an upper limit voltage of the lithium ion battery.
In this case, even if a lithium ion battery that strictly requires management of the upper limit voltage during charging is used, charging can be performed without greatly exceeding the upper limit voltage of each lithium ion battery.

Further, the present invention provides a charging method for power storage means that performs charging by supplying a charging current from an external power source in a state where a plurality of power storage means are connected in series, and performs constant current control at the start of the charging process and First, the terminal voltage of each storage means is detected, and constant voltage charging is sequentially started with respect to the storage means whose detected value has reached a predetermined voltage set in advance, and the terminal voltages of the storage means are respectively maintained at a predetermined voltage. And performing a second control for controlling a charging current from the external power source so that the predetermined voltage is applied to the last power storage means that has reached the predetermined voltage.
According to the present invention, even when there is a variation in the charging state of each power storage means, the full charge can be efficiently performed by switching from constant current charging to constant voltage charging while avoiding overcharging for each power storage means.
Moreover, the power loss due to the loss during charging can be reduced as compared with the conventional case.

  According to the present invention, even when there is a variation in the state of charge of each power storage means, it is possible to efficiently perform full charge by switching from constant current charge to constant voltage charge while avoiding overcharge for each power storage means. It is possible to provide a power supply device and a method for charging the power storage means that can reduce power loss due to time loss as compared with the conventional case.

Hereinafter, a power supply device according to an embodiment of the present invention will be described with reference to FIGS.
FIG. 1 is a circuit diagram showing a configuration of a power supply device according to an embodiment of the present invention, FIG. 2 is a flowchart showing a charging procedure used in the power supply device, and FIG. 3 is a first control in the power supply device. FIG. 4 is a circuit diagram for explaining a second control in the power supply device.
3 and 4 show only a portion to be energized in the power supply device for convenience.
The power supply device according to this embodiment will be described as a power supply device mounted on a vehicle.

As shown in FIG. 1, the power supply device includes a connection circuit 10 that connects three battery modules BT (BT1 to BT3) in series.
The battery module BT is configured by connecting three single batteries (secondary batteries) 11 in parallel.
In this embodiment, the battery module BT corresponds to a power storage unit.
The cell 11 of this embodiment is a rechargeable lithium ion battery.
A terminal of the connection circuit 10 is connected to an electric motor (not shown) for driving as a load via an inverter (not shown) during discharging.
As shown in FIG. 1, the terminal of the connection circuit 10 is connected to an external power supply 13 for charging via a converter 15 provided in the power supply device during charging.

The terminal of each battery module BT is connected to a control circuit 12 installed separately from the connection circuit 10, and the terminal voltage Vi (V1 to V3) of each battery module BT is detected by the control circuit 12.
The control circuit 12 has a function as a voltage detection means for detecting the terminal voltages V1 to V3, and also has a function as a timer means.
Further, the control circuit 12 controls the external power supply 13 by controlling the converter 15 as control means.

The power supply device includes semiconductor elements T (T1 to T3) connected in parallel for each battery module BT.
The semiconductor element T is a semiconductor element that can be energized only in one direction, and in this embodiment, an IGBT (insulated gate bipolar transistor) 14 is used.
The semiconductor element T is disposed in such a direction that it is not energized when the battery module BT is discharged, and the semiconductor element T can be energized during charging.

In the semiconductor element T connected in parallel with the battery module BT, the emitter terminal Ei (E1 to E3) of the IGBT 14 is connected to the negative electrode of the battery module BT.
The collector terminals Ci (C1 to C3) of each IGBT 14 are connected to the positive electrode of the battery module BT, and the respective gate terminals Gi (G1 to G3) are connected to the control circuit 12.
The gate terminals G1 to G3 are energized from the control circuit 12 to enable energization from the collector terminal C to the emitter terminal E.
That is, the control circuit 12 has a function of controlling energization of the semiconductor element T as control means.

Next, charging of the battery module BT using the power supply device according to the embodiment of the present invention will be described with reference to FIGS.
While the electric motor is in a driving stop state, the key switch of the vehicle is kept on, the external power supply 13 for charging is connected to the power supply device, and the battery modules BT are charged.
FIG. 2 is a flowchart showing a charging process procedure for each battery module BT using the power supply device.

First, constant current charging (referred to as “CC charging” in FIG. 2) is performed in a state where the battery modules BT1 to BT3 are connected in series (see S1 in FIG. 2).
In the constant current charging, the charging current flowing through the connection circuit 10 is constant, and the terminal voltage Vi of each battery module BT increases with the charging time.
In a state where each battery module BT does not reach the upper limit voltage Vup as a predetermined voltage set in advance, no voltage is applied to the gate terminal Gi of the semiconductor element T, and all the semiconductor elements T are in an off state in which no current is supplied (FIG. (See S2 in 2).

The control circuit 12 detects the terminal voltage Vi of each battery module BT that is being charged by constant current charging.
Specifically, the control circuit 12 receives the program control and detects the terminal voltage Vi at a predetermined timing.
The terminal voltage Vi of the battery module BT reaches the upper limit voltage Vup in a relatively short time after starting constant current charging. For example, if the deterioration state of each battery module BT is different, the terminal voltage Vi becomes the upper limit voltage Vup for each battery module BT. The time to reach is different.

In this embodiment, the control circuit 12 determines whether there is a battery module BT having a terminal voltage Vi that has reached a preset upper limit voltage Vup (see S3 in FIG. 2).
When the terminal voltage Vi that reaches the upper limit voltage Vup does not exist, all the semiconductor elements T are turned off and constant current charging is continued.

  When there is a terminal voltage Vi that has reached the upper limit voltage Vup, the battery module BT of that terminal voltage Vi is the battery module BT that has reached the upper limit voltage Vup in order at a timing other than the last (first or second in this embodiment). The control circuit 12 determines whether the battery module BT has reached the upper limit voltage Vup at the end (third) (see S4 in FIG. 2).

When the control circuit 12 determines that the battery module BT having the terminal voltage Vi that has reached the upper limit voltage Vup is the battery module BT that has sequentially reached the upper limit voltage Vup at a timing other than the last, the control circuit 12 A voltage is applied to the gate terminal Gi of the semiconductor element T connected in parallel with the battery module BT so that the terminal voltage Vi of the BT becomes the upper limit voltage Vup, thereby controlling the current flowing through the semiconductor element T (FIG. 2). See S6).
The resistance value of the semiconductor element T varies depending on the voltage applied to the gate terminal Gi, a current corresponding to the resistance value passes through the semiconductor element T, and the semiconductor element T is turned on.
The upper limit voltage Vup is generated in the semiconductor element T, whereby the terminal voltage Vi is maintained at the upper limit voltage Vup for the battery modules BT that sequentially reach the upper limit voltage Vup at timings other than the last, and charging related to constant voltage charging is performed. Control begins.
The control by the control circuit 12 that maintains the terminal voltage Vi at the upper limit voltage Vup for the battery module BT corresponds to the first control.
Furthermore, the first control is a predetermined value in which the detection value of the control circuit 12 is set in advance in the battery module BT after the charge control is performed by maintaining the semiconductor element T in the OFF state from the start of the charging process. In this control, the resistance values of the semiconductor elements T connected in parallel to the battery modules BT are controlled so that the battery modules BT having reached the voltage are sequentially charged at a constant voltage.

By the first control, overcharging of the battery module BT having the terminal voltage Vi that has reached the upper limit voltage Vup is avoided, and the battery module BT is charged with constant current charging by charging control related to constant voltage charging. A small charging current flows.
In addition, most of the current that does not flow through the battery module BT is used to charge other battery modules BT that have not reached the upper limit voltage Vup through the semiconductor element T in the on state.
The control circuit 12 determines whether or not the charging is finished (see S8 in FIG. 2).
When the charging is not finished, the semiconductor element T is continuously energized by applying a voltage to the gate terminal Gi. When the charging is finished, the charging process is finished.

When the control circuit 12 determines that the battery module BT having the terminal voltage Vi that has reached the upper limit voltage Vup sequentially starts the above control and is finally the battery module BT that has reached the upper limit voltage Vup, this battery The control circuit 12 controls the converter 15 to control the current of the external power supply 13 so that the terminal voltage Vi of the module BT becomes the upper limit voltage Vup (see S5 in FIG. 2).
The semiconductor element T in the on state controls the constant voltage charging of the corresponding parallel battery module BT, and the charging control of the battery module BT in parallel with the semiconductor element T in the off state (the battery module that has finally reached the upper limit voltage). I do.
The semiconductor element Ti connected in parallel with the battery module BT that finally reaches the upper limit voltage Vup is not energized in the off state.
The charging of the battery module BT at this time is constant voltage charging (denoted as “CV charging” in FIG. 2) in which the current value is controlled by the control circuit 12 and the terminal voltage Vi becomes a constant voltage value (Vup). is there.
In constant voltage charging, the current is reduced with time and the current value approaches zero.

The terminal voltage Vi of the battery module BT is maintained at the upper limit voltage Vup by constant voltage charging in a state where the energization of the semiconductor element T connected in parallel to the battery module BT is cut off.
The control by the control circuit 12 that maintains the terminal voltage Vi of the battery module BT at the upper limit voltage Vup by constant voltage charging in a state where the energization of the semiconductor element T connected in parallel with the battery module BT is cut off is the second control. Equivalent to.
Furthermore, the second control is a control for controlling the charging current from the external power source 13 so that the upper limit voltage Vup is applied to the last battery module BT that has reached the upper limit voltage Vup. The control is to maintain the terminal voltage Vi of the battery module BT that has finally reached the upper limit voltage Vup at the upper limit voltage Vup while the semiconductor element T connected in parallel with the battery module BT having reached the voltage Vup is maintained in the off state. .

In charging the battery module BT by constant voltage charging, the control circuit 12 determines whether a predetermined time (constant voltage charging time) set in advance has elapsed (see S7 in FIG. 2).
The predetermined time related to the constant voltage charging is a time for performing charging by constant voltage charging, and is a time set according to the type and performance of the battery modules BT1 to BT3.
If the predetermined time has not elapsed, the control circuit 12 continues to charge the BT by constant voltage charging.
When the predetermined time has elapsed, the control circuit 12 requests the end of charging (see S9 in FIG. 2).
Then, under the control of the control circuit 12, the supply of current from the external power supply 13 is stopped.
A series of steps S1 to S9 shown in FIG. 2 are processed in parallel for each battery module BT.

Here, a case where the upper limit voltage Vup is reached in the order of the terminal voltages V3, V2, and V1 will be described as a specific example of charging the battery modules BT1 to BT3.
When the terminal voltage V3 of the battery module BT3 first reaches the upper limit voltage Vup, the control circuit 12 performs the first control, applies a voltage to the gate terminal G3 of the semiconductor element T3 connected in parallel with the battery module BT3, and the semiconductor The element T3 is turned on.
At this time, the control circuit 12 controls the voltage applied to the gate terminal G3 so that the voltage of the semiconductor element T3 becomes the upper limit voltage Vup.
When the voltage of the semiconductor element T3 becomes the upper limit voltage Vup, the terminal voltage V3 of the battery module BT3 connected in parallel with the semiconductor element T3 becomes the upper limit voltage Vup.
That is, the control circuit 12 maintains the terminal voltage V3 at the upper limit voltage Vup for the battery module BT3 by the first control.
By applying a voltage to the gate terminal G3, a resistance value corresponding to the upper limit voltage Vup is generated in the semiconductor element T3, and a current corresponding to the resistance value passes through the semiconductor element T3.
The semiconductor element T3 has a loss during energization.
As shown in FIG. 3, the current passing through the semiconductor element T3 is used to charge the battery modules BT1 and BT2 that have not reached the upper limit voltage Vup.

Next, when the terminal voltage V2 of the battery module BT2 reaches the upper limit voltage Vup next to the battery module BT3, the control circuit 12 performs the first control.
The control circuit 12 applies a voltage to the gate terminal G2 of the semiconductor element T2 connected in parallel with the battery module BT2, thereby turning on the semiconductor element T2.
At this time, the control circuit 12 controls the voltage applied to the gate terminal G2 so that the voltage of the semiconductor element T2 becomes the upper limit voltage Vup.
When the voltage of the semiconductor element T2 becomes the upper limit voltage Vup, the terminal voltage V2 of the battery module BT2 connected in parallel with the semiconductor element T2 becomes the upper limit voltage Vup.
That is, the control circuit 12 maintains the terminal voltage V2 at the upper limit voltage Vup for the battery module BT2 by the first control.
The semiconductor element T2 generates a loss during energization.
The current passing through the semiconductor elements T2 and T3 is used for charging the battery module BT1 that has not reached the upper limit voltage Vup.

When the battery module BT1 finally reaches the upper limit voltage Vup, the control circuit 12 performs the second control, and controls the current so that the battery module BT1 has the upper limit voltage Vup.
The semiconductor element T1 connected in parallel with the battery module BT1 is in an off state and is not energized, and the battery module BT1 at this time is charged by constant voltage charging in which the terminal voltage V1 becomes a constant voltage value (Vup). .
As shown in FIG. 4, the control circuit 12 performs control to supply a charging current by constant voltage charging to the battery module BT1.
That is, the control circuit 12 maintains the terminal voltage V1 at the upper limit voltage Vup for the battery module BT1 by the second control.
Since the semiconductor element T1 is in the off state, no loss occurs when the semiconductor element T1 is energized.

Charging of the battery module BT1 by constant voltage charging is continued for a predetermined time set in advance.
At this time, in the battery modules BT2 and BT3, energization to the gate terminals G2 and G3 is continued so that the terminal voltages V2 and V3 become the upper limit voltage Vup.
When the predetermined time has elapsed, the supply of current from the external power supply 13 is stopped under the control of the control circuit 12, the first control and the second control by the control circuit 12 are canceled, and the battery modules BT1 to BT3 are charged. Ends.
When charging of battery modules BT1 to BT3 is completed, converter 15 and external power supply 13 are disconnected.
Incidentally, when the vehicle travels, the current of the battery modules BT1 to BT3 is supplied as a discharge current to the electric motor for travel driving via the inverter.

The compressor according to this embodiment has the following effects.
(1) Since two types of control such as the first control and the second control are performed, even when the charging state of each battery module BT varies, constant current charging is performed while avoiding overcharging for each battery module BT. Switching from constant voltage charging to constant voltage charging enables efficient full charging. Further, when switching from constant current charging to constant voltage charging, it is not necessary to switch the connection state of the battery module from series connection to parallel connection.
(2) In the semiconductor element T connected in parallel with the battery module BT subjected to the first control, a loss occurs when the semiconductor element T is energized. The terminal voltage Vi of the battery module BT is maintained at the upper limit voltage Vup by constant voltage charging. Therefore, since the energization of the semiconductor element T connected in parallel with the battery module BT subjected to the second control is cut off, no loss occurs in the semiconductor element T, and almost no power loss occurs in the second control.

(3) Since the battery module BT that finally reached the upper limit voltage Vup maintains the upper limit voltage Vup by constant voltage charging without causing any loss, a conventional power source that generates a loss for each charging of each battery module BT Compared with the device, shortening of the charging time can be expected. In addition, a constant voltage charging current flows from the battery module BT that has reached the upper limit voltage Vup, and the charging time is shortened because the current gradually decreases and the battery module BT is fully charged. Can be planned.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the gist of the invention.
In the above-described embodiment, the IGBT is used as the semiconductor element energized in one direction. However, a bipolar transistor or MOSFET having a function of energizing in one direction may be used as the semiconductor element.
In the above embodiment, the battery module is a combination of a plurality of rechargeable lithium ion batteries as the power storage means, but the power storage means is a rechargeable single cell other than a lithium ion battery (for example, a nickel cadmium battery or a nickel metal hydride battery). The battery module which combined these may be sufficient. Alternatively, the unit cell itself may be used as the power storage means, and the capacitor may be used as the power storage means.
In the above embodiment, the power supply device is mounted on the vehicle. However, the power supply device may be mounted on a mobile body other than the vehicle, or the power supply device may be provided in a facility that is not a mobile body. .
In the above embodiment, the number of the single cells 11 or the battery modules is not limited, although the number of the single cells 11 or the battery modules constituting the battery module is three.
In the above embodiment, the control circuit has all the functions of the voltage detection means, the timer means and the control means. However, the voltage detection means, the timer means and the control means may be installed independently of each other.

It is a circuit diagram which shows the structure of the power supply device which concerns on embodiment of this invention. It is a flowchart which shows the procedure of the charging process of the battery module by a power supply device. It is a circuit diagram explaining the 1st control in a power unit. It is a circuit diagram explaining the 2nd control in a power supply device. It is a circuit diagram which shows the structure of the conventional power supply device.

Explanation of symbols

10 Connection Circuit 11 Cell 12 Control Circuit 13 External Power Supply 14 IGBT
15 Converter BT (BT1, BT2, BT3) Battery module T (T1, T2, T3) Semiconductor element Ci (C1-C3) Collector terminal Ei (E1-E3) Emitter terminal Gi (G1, G2, G3) Gate terminal Vi ( V1, V2, V3) Terminal voltage 20 for each battery module Voltage equalization devices 21A, 21B Cell 23 Shunt regulator 24 Bipolar transistors R1, R2, R3, RV Resistance

Claims (6)

In a power supply device that performs charging by supplying a charging current from an external power supply with a plurality of power storage means connected in series,
A semiconductor element connected in parallel for each power storage means and capable of energizing only in the charging direction;
Voltage detection means for detecting the terminal voltage of each power storage means during charging;
Control means for controlling the resistance value of the semiconductor element based on the detection value from the voltage detection means,
The control means performs charge control by maintaining the semiconductor element in an off state from the start of charge processing, and then the detection value of the voltage detection means reaches a preset predetermined voltage in the power storage means For the power storage means, a first control is performed to control the resistance values of the semiconductor elements connected in parallel to the power storage means so as to sequentially perform constant voltage charging,
A power supply apparatus that performs a second control for controlling a charging current from the external power supply so that a predetermined voltage is applied to the last power storage unit that has reached a predetermined voltage. The first control includes
Control the resistance value of the semiconductor element to generate a predetermined voltage in the semiconductor element, thereby maintaining the terminal voltage of the power storage means at the predetermined voltage;
The second control includes
The control is to maintain the terminal voltage of the power storage means that has finally reached the predetermined voltage at the predetermined voltage while the semiconductor element connected in parallel with the power storage means that has finally reached the predetermined voltage is maintained in the off state. The power supply device according to claim 1.   3. The power supply device according to claim 1, wherein the control unit terminates the charging control of all power storage units after a predetermined time has elapsed after starting the second control.   The control means determines whether or not the power storage means that has reached a predetermined voltage is the last power storage means. If it is determined that the power storage means is not the last power storage means, it starts the first control and determines that it is the last power storage means. 4. The power supply device according to claim 1, wherein each of the semiconductor elements is controlled to start the second control.   5. The power supply device according to claim 1, wherein the power storage unit is a lithium ion battery, and the predetermined voltage is an upper limit voltage of the lithium ion battery. In the charging method of the power storage means for performing charging by supplying a charging current from an external power source in a state where a plurality of power storage means are connected in series,
At the beginning of the charging process, while performing constant current control,
The terminal voltage of each power storage means is detected, and constant voltage charging is sequentially started for the power storage means whose detected value has reached a predetermined voltage, and the terminal voltage of the power storage means is maintained at the predetermined voltage. Perform the first control,
A method for charging power storage means, comprising: performing a second control for controlling a charging current from the external power supply so that a predetermined voltage is applied to the last power storage means that has reached a predetermined voltage.