KR101181859B1 - Charge and discharge apparatus for secondary cell and driving method thereof - Google Patents

Abstract

The secondary battery charging and discharging device includes a charge and discharge driver for generating a charge and discharge current for charging and discharging a secondary battery, and measuring the magnetism generated by the charge and discharge current flowing between the secondary battery and the charge and discharge driver. A magnetic sensor for measuring a discharge current amount and generating a feedback signal indicating the measured charge / discharge current amount, and receiving the feedback signal and comparing the measured set value of the charge / discharge current amount with the charge / discharge current amount, It includes a control unit for controlling. In the charge / discharge process of the secondary battery, the charge / discharge current amount can be controlled more precisely.

Description

Charging and discharging apparatus for secondary cell and driving method

The present invention relates to a secondary battery charging and discharging device and a driving method thereof, and more particularly, to a secondary battery charging and discharging device for sensing the amount of charge and discharge current of the secondary battery and a driving method thereof.

Recently, the use of portable devices such as mobile phones, personal digital assistants (PDAs), netbooks, and notebook computers is increasing. The portable device is supplied with power using a secondary battery capable of charging and discharging due to its use characteristics. Secondary batteries used in portable devices need to be increased in size and weight with increased charging capacity.

In the manufacturing process of the secondary battery, a charge and discharge process is performed to increase the charge capacity of the secondary battery. The charge and discharge process of the secondary battery is a process of increasing the charge capacity of the secondary battery by repeating the charging and discharging of the secondary battery. In the charge and discharge process of the secondary battery, it is most important how precisely the current value can be continuously charged and discharged. To this end, it is important to accurately sense and control the amount of charge and discharge current of the secondary battery in the charge and discharge process of the secondary battery.

In a typical secondary battery charge / discharge device, a shunt resistor is connected in series between a charge and discharge circuit and a secondary battery to measure a charge / discharge current amount, and a voltage difference between both ends of the shunt resistor varies according to the amount of current. As the shunt resistor is connected in series between the charge / discharge circuit and the secondary battery, a voltage drop caused by the shunt resistor is generated, which causes a loss of the charge / discharge device. The temperature of the shunt resistor is changed by the loss caused by the shunt resistor, and the resistance value of the shunt resistor is changed. As a result, the voltage value measured by the shunt resistor varies with temperature, and a measurement error of the actual charge / discharge current amount of the secondary battery occurs. That is, there exists a problem that the measurement precision of the charge / discharge current amount of the secondary battery which is the most important in a charge / discharge process falls.

In order to minimize this problem, a shunt resistor having a very small resistance change with temperature is used. This shunt resistor is very expensive and causes a price increase of the charge / discharge device. Alternatively, a separate heat sink or fan may be attached to the shunt resistor to minimize the temperature of the shunt resistor, or a method of correcting the measured voltage value according to the temperature of the shunt resistor may be used. It does not solve the problem fundamentally. In particular, in the case of the high output charge / discharge device required for charging and discharging a high capacity secondary battery, the problem caused by the shunt resistance may become more serious because the amount of current to be charged and discharged is quite large.

An object of the present invention is to provide a secondary battery charging and discharging device and a driving method thereof that can improve the measurement accuracy of the charge and discharge current amount of the secondary battery.

The secondary battery charging and discharging device according to an embodiment of the present invention by the charge and discharge driver for generating a charge and discharge current for charge and discharge of the secondary battery, by the charge and discharge current flowing between the secondary battery and the charge and discharge driver A magnetic sensor for measuring the amount of charge / discharge current generated by measuring the generated magnetism, and generating a feedback signal indicating the measured amount of charge / discharge current; and a set value of the measured amount of charge / discharge current and the amount of charge / discharge current received from the feedback signal. Comprising a control unit for controlling the charge-discharge drive unit.

The controller converts the feedback signal into a digital signal, a memory in which the set value of the charge / discharge current amount is recorded, and the charge generated in the charge / discharge driver by comparing the set value of the digital signal with the charge / discharge current amount. It may include a calculation processor for generating a charge-discharge control signal for adjusting the amount of discharge current and transmits the charge-discharge control signal to the charge-discharge driving unit.

The charge and discharge driver may include a conversion circuit for generating the charge and discharge current for charge and discharge of the secondary battery, and a drive circuit for controlling the amount of current converted in the conversion circuit according to the charge and discharge control signal.

The power supply unit may further include a power supply unit configured to receive an AC voltage supplied from an external source and rectify the DC voltage required to generate the charge / discharge current in the charge / discharge driver.

The power supply unit may maintain the DC voltage constant and change the amount of current according to the state of charge of the secondary battery.

The conversion circuit may be a bidirectional DC-DC converter for converting a voltage between the DC voltage of the power supply unit and the DC voltage generating the charge / discharge current.

The charging and discharging driving unit may further include a jig unit connected to the positive charging and discharging line and the negative charging and discharging line and fastened to the secondary battery.

The magnetic sensor may be installed at a predetermined distance from one of the positive charge and discharge lines and the negative charge and discharge lines.

The feedback signal may be a current generated according to the magnitude and direction of the magnetic lines of magnetic force. The feedback signal may be a current having the same magnitude as the charge / discharge current.

The magnetic sensor may be at least one of a Hall element, a MR (MagnetroResistance effect) element, and a Josephson device.

According to another aspect of the present invention, there is provided a method of driving a secondary battery charge / discharge device, by measuring magnetism generated by a charge / discharge current for charging or discharging a secondary battery, measuring the amount of charge / discharge current of the secondary battery, Comparing the measured charge and discharge current amount with a set value, and adjusting the charge and discharge current amount of the secondary battery according to a comparison result between the measured charge and discharge current amount and the set value.

The method may further include generating a feedback signal corresponding to the measured charge / discharge current amount.

The feedback signal may be a current generated according to the magnitude and direction of the magnetic lines of magnetic force. The feedback signal may be generated with a current amount equal to the current amount of the charge / discharge current.

The method may further include converting the feedback signal into a digital signal.

In the charging and discharging process of the secondary battery, no additional device for cooling the shunt resistor is required, and an additional process of correcting the measured voltage value according to the temperature change of the shunt resistor can be reduced, and the charge and discharge according to the temperature change of the shunt resistor can be reduced. The problem that the measurement accuracy of the amount of current falls is solved. In the charge / discharge process of the secondary battery, the charge / discharge current amount can be controlled more precisely.

1 is a block diagram schematically showing the configuration of a secondary battery charge / discharge device according to an embodiment of the present invention.
2 is a flowchart illustrating a method of driving a secondary battery charge / discharge device according to an embodiment of the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may be embodied in many different forms and is not limited to the embodiments described herein.

In addition, in the various embodiments, components having the same configuration are represented by the same reference symbols in the first embodiment. In the other embodiments, only components different from those in the first embodiment will be described .

In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

Throughout the specification, when a part is referred to as being "connected" to another part, it includes not only "directly connected" but also "electrically connected" with another part in between . Also, when an element is referred to as "comprising ", it means that it can include other elements as well, without departing from the other elements unless specifically stated otherwise.

1 is a block diagram schematically showing the configuration of a secondary battery charge / discharge device according to an embodiment of the present invention.

Referring to FIG. 1, the secondary battery charge / discharge device includes a power supply unit 10, a charge / discharge driver 20, a controller 30, a magnetic sensor 40, and a jig unit 50. The charge / discharge driver 20 includes a conversion circuit 21 and a drive circuit 22. The controller 30 includes a memory 31, an arithmetic processor 32, and an A / D converter 33.

The secondary battery charging and discharging apparatus performs a secondary battery charging and discharging process which repeatedly performs a charging drive for charging the secondary battery 60 and a discharge driving for discharging the secondary battery 60.

The power supply unit 10 receives the commercial power of the AC voltage supplied from the outside to rectify the DC voltage and charges the DC voltage from the charge / discharge drive unit 20 when the secondary battery 60 is charged and driven. Is converted to a predetermined voltage required to generate a current required for charging) and output. In addition, the power supply unit 10 receives a predetermined voltage of DC from the charge / discharge driving unit 20 to generate an alternating current voltage and regenerates the commercial power when driving the secondary battery 60. For example, the AC voltage of the commercial power source may be AD 220V, and the predetermined voltage required to generate a current required for charging the secondary battery 60 in the charge / discharge drive unit 20 or the power supply unit in the charge / discharge drive unit 20. The predetermined voltage applied to 10 may be DC 380V. The voltage output from the power supply unit 10 to the charge / discharge drive unit 20 or the voltage output from the charge / discharge drive unit 20 to the power supply unit 10 is kept constant (for example, DC 380V), and the amount of current is charged. It varies depending on the discharge state and the state of the secondary battery.

The charging and discharging driving unit 20 is connected to the power supply unit 10 and receives a predetermined DC voltage from the power supply unit 10 during the secondary battery charge driving, and applies the predetermined DC voltage to the power supply unit during the secondary battery discharge driving. Output to 10). The charging / discharging driving unit 20 converts the DC voltage applied from the power supply unit 10 to the current (or voltage) set for charging the secondary battery 60 using the conversion circuit 21 during the secondary battery charging driving. To the secondary battery 60. The charging / discharging driving unit 20 discharges a current (or voltage) set in the secondary battery 60 by using the conversion circuit 21 during the secondary battery discharge driving so as to generate a predetermined DC voltage (for example, DC 380V). It generates and delivers to the power supply (10). That is, the charge / discharge driver 20 may be a bidirectional DC-DC converter that converts a voltage between the DC voltage of the power supply unit 10 and the DC voltage to generate the charge / discharge current for charge / discharge of the secondary battery. The charge / discharge driver 20 functions as a bidirectional DC-DC converter having a charging function and a discharging function to generate a current (or voltage) required for charging and discharging the secondary battery 60. The conversion circuit 21 generates a charge / discharge current set for charge / discharge of the secondary battery. The amount of current (or voltage) converted by the conversion circuit 21 of the charge / discharge drive unit 20 is controlled by the drive circuit 22. The driving circuit 22 controls the amount of current (or voltage) converted by the conversion circuit 21 according to the charge / discharge control signal transmitted from the controller 30.

The jig unit 50 is connected to the charge / discharge driver 20 and the positive charge / discharge line 71a and the negative charge / discharge line 71b, and is coupled to the secondary battery 60 to be output from the charge / discharge drive unit 20. The secondary battery 60 is fixed so that the current is smoothly transferred to both terminals (+) and the negative terminal (−) of the secondary battery 60. The jig unit 50 has an optimized contact area between both terminals (+) and the negative terminal (−) of the secondary battery 60 so that the secondary battery 60 can be easily charged and discharged.

The magnetic sensor 40 flows from the charge / discharge driver 20 to the charge / discharge drive unit 20 when the secondary battery charge is driven, and the amount of current flowing from the charge / discharge drive unit 20 to the secondary battery 60. Measure the amount of current. That is, the magnetic sensor 40 can measure both the amount of current during the secondary battery charge driving and the amount of current during the secondary battery discharge driving.

Hereinafter, the current flowing through the positive charging / discharging line 71a or the negative charging / discharging line 71b at the time of secondary battery charge driving or discharge driving is called charge / discharge current, and the amount of current is called charge / discharge current amount.

The magnetic sensor 40 is installed at a predetermined distance apart from the positive charge / discharge line 71a or the negative charge / discharge line 71b, and is applied to the charge / discharge current flowing through the positive charge / discharge line 71a or the negative charge / discharge line 71b. The amount of charge and discharge current of the secondary battery is measured by measuring the magnetism generated by the secondary battery. For example, the magnetic sensor 40 is installed on the positive charge / discharge line 71a in a non-contact manner to be spaced apart by a predetermined distance to measure the magnetism generated by the charge / discharge current flowing through the positive charge / discharge line 71a. Measure the amount of charge and discharge current.

The magnetic sensor 40 generates a current according to the magnitude and direction of the magnetic force line to be measured, and transmits the generated current to the controller 30 as a feedback signal. Since the magnitude of the current generated by the magnetic sensor 40 depends on the magnitude and direction of the magnetic field or magnetic field to be measured, the feedback signal indicates the amount of charge / discharge current flowing through the positive charge / discharge line 71a or the negative charge / discharge line 71b. Instruct.

The feedback signal may be a current having the same magnitude as that flowing through the positive charge / discharge line 71a or the negative charge / discharge line 71b. That is, the magnetic sensor 40 may measure the magnitude and direction of the magnetic force line to generate a current having the same magnitude as the charge / discharge current and transmit it to the controller 30. At this time, as the amount of current transmitted as the feedback signal from the magnetic sensor 40 is closer to the actual amount of charge / discharge current that charges / discharges the secondary battery 60, a more precise charge / discharge process of the secondary battery may be performed.

MR (MagnetroResistance effect) using the magnetoresistance effect of increasing the electric resistance under the influence of the Hall element or the magnetic field using the Hall effect that generates a voltage when the magnetic field is vertically applied to the current flowing through the semiconductor by the magnetic sensor 40 A device, a Josephson device using a superconductor, or the like can be employed.

The controller 30 compares the charge / discharge current amount with the set value of the charge / discharge current amount by using the feedback signal transmitted from the magnetic sensor 40. That is, the controller 30 calculates the difference between the amount of current flowing from the charge / discharge driver 20 to the secondary battery 60 or the amount of current flowing from the secondary battery 60 to the charge / discharge driver 20 and a preset current amount. In addition, a charge / discharge control signal for controlling an operation of the charge / discharge driver 20 is generated and transmitted to the driving circuit 22 so that the measured charge / discharge current amount and the set value of the charge / discharge current amount are the same.

To this end, the controller 30 may include an A / D converter 33 for converting an analog feedback signal transmitted from the magnetic sensor 40 into a digital signal, a memory 31 in which a set value of charge / discharge current amount is recorded, and a charge / discharge current. Comprising an operation processor 32 for generating a charge-discharge control signal for adjusting the amount of charge and discharge current generated by the charge-discharge driver 20 by comparing the set value and the digital signal converted by the A / D converter 33. In the memory 31, the set value of the charge / discharge current amount of the secondary battery determined according to the type and characteristics of the secondary battery or the user setting is recorded. The operation processor 32 transmits the charge / discharge control signal to the drive circuit 22, and the drive circuit 22 supplies the charge / discharge current amount (or voltage) converted by the conversion circuit 21 according to the transmitted charge / discharge control signal. To control.

2 is a flowchart illustrating a method of driving a secondary battery charge / discharge device according to an embodiment of the present invention.

Referring to FIG. 2, the secondary battery charging / discharging device using the magnetic sensor 40 has a positive charge / discharge line 71a or a negative charge / discharge line by charge / discharge current for charging or discharging the secondary battery 60. The magnetism generated in 71b) is measured to measure the amount of charge and discharge current of the secondary battery 60 (S110).

When charging the secondary battery, the power supply unit 10 is supplied with a commercial power source of an alternating voltage and converted into a predetermined DC voltage necessary to generate a current required for charging the secondary battery 60 to be charged to the charge / discharge driver 20. To pass. The power supply unit 10 maintains a constant voltage of approximately DC 380V and varies the amount of current according to the state of charge of the secondary battery. The charge / discharge drive unit 20 converts the DC voltage transmitted from the power supply unit 10 into a current (or voltage) set for charging the secondary battery 60 and transmits it to the secondary battery 60. At this time, the positive charge is transferred to the positive terminal (+) of the secondary battery 60 through the positive charge and discharge line (71a), the negative charge (negative terminal) of the secondary battery 60 through the negative charge and discharge line (71b) -) Is passed. Accordingly, magnetism is formed around the positive charge / discharge line 71a and the negative charge / discharge line 71b. The magnitude of the magnetic force line of the magnetism is proportional to the amount of current flowing through the positive charge / discharge line 71a and the negative charge / discharge line 71b.

In the discharge driving of the secondary battery, the charge / discharge driving unit 20 discharges the current (or voltage) set in the secondary battery 60. In this case, positive charges emitted from both terminals (+) of the secondary battery 60 are transferred to the charge / discharge driving unit 20 through the positive charge / discharge line 71a and the negative terminal (−) of the secondary battery 60. The negative charges emitted from the charges are transferred to the charge and discharge driver 20 through the negative charge and discharge lines 71b. As a result, magnetism is formed around the positive charge / discharge line 71a and the negative charge / discharge line 71b. The magnetic force line direction is opposite to the magnetic force line direction generated during the charging operation of the secondary battery.

The magnetic sensor 40 measures the magnitude and direction of the magnetic force lines of the magnetic force generated in any one of the positive charge and discharge lines 71a and the negative charge and discharge lines 71b. Since the direction of the magnetic field of magnetic force generated during the charging operation of the secondary battery and the discharge driving of the secondary battery is reversed, the magnetic sensor 40 uses the direction of the magnetic field to be measured to perform the charging and discharging driving of the secondary battery. Can be distinguished. In addition, the magnetic sensor 40 may measure the amount of current flowing in the positive charge / discharge line 71a and the negative charge / discharge line 71b from the magnitude of the magnetic force line of the magnetic sensor 40.

The magnetic sensor 40 transmits the measured charge / discharge current amount to the controller 30, and the controller 30 compares the measured charge / discharge current amount with a set value (S120). The magnetic sensor 40 generates a current in accordance with the magnitude and direction of the magnetic lines of magnetic force, and transmits the generated current to the controller 30 as a feedback signal. That is, the magnetic sensor 40 generates a feedback signal corresponding to the measured charge / discharge current amount. The magnetic sensor 40 may generate a feedback signal with a current amount equal to the charge / discharge current amount. The control unit 30 converts the feedback signal into a digital signal using the A / D converter 33 and compares the converted digital signal with a set value of the charge / discharge current recorded in the memory 31.

The charge / discharge driver 20 adjusts the charge / discharge current amount of the secondary battery according to a result of comparing the measured charge / discharge current amount with the set value (S130). The controller 30 compares the digital signal with the charge / discharge set value, and transmits a charge / discharge control signal for controlling the amount of charge / discharge current output from the charge / discharge driver 20 to reduce the difference, to the charge / discharge driver 20. The charge / discharge driver 20 adjusts the charge / discharge current amount according to the charge / discharge control signal.

The process of measuring the charge and discharge current amount of the secondary battery using the magnetic sensor 30 (S110), the process of comparing the measured charge and discharge current amount and the set value (S120) and the process of adjusting the secondary charge and discharge current amount according to the comparison result (S130) ) Is performed repeatedly. Accordingly, the charge / discharge current amount of the secondary battery can be adjusted and maintained in the same manner as the set value.

Therefore, the secondary battery charge / discharge device according to the present invention can precisely and continuously perform charging and discharging of the secondary battery according to the set value of the charge / discharge current amount. In addition, compared with the conventional secondary battery charge and discharge process using a shunt resistor, the secondary battery charge and discharge device according to the present invention does not require an additional device for cooling the shunt resistance, and according to the temperature change of the shunt resistor The problem that the measurement accuracy of the charge / discharge current amount decreases can be solved.

It is to be understood that both the foregoing general description and the following detailed description of the present invention are illustrative and explanatory only and are intended to be illustrative of the invention and are not to be construed as limiting the scope of the invention as defined by the appended claims. It is not. Therefore, those skilled in the art will understand that various modifications and equivalent other embodiments are possible. Accordingly, the true scope of the present invention should be determined by the technical idea of the appended claims.

10: power supply
20: charge and discharge drive
30:
40: magnetic sensor
50: jig unit
60: secondary battery

Claims (16)

A charge / discharge driver for generating a charge / discharge current for charge / discharge of the secondary battery;
A magnetic sensor for measuring the amount of charge / discharge current by measuring the magnetism generated by the charge / discharge current flowing between the secondary battery and the charge / discharge driving unit, and generating a feedback signal indicating the measured amount of charge / discharge current; And
And a controller configured to control the charge / discharge driver by receiving the feedback signal and comparing the measured charge / discharge current amount with a set value of the charge / discharge current amount.
The charging / discharging driving unit includes a bidirectional DC-DC converter for converting a voltage between a DC voltage rectified from an AC voltage supplied from the outside and the DC voltage generating the charge / discharge current. The apparatus of claim 1, wherein the control unit
An A / D converter converting the feedback signal into a digital signal;
A memory in which the set value of the charge / discharge current amount is recorded; And
And a calculation processor for comparing the digital signal with the set value of the charge / discharge current amount and generating a charge / discharge control signal for controlling the charge / discharge current amount generated by the charge / discharge driver and transferring the charge / discharge control signal to the charge / discharge driver. Discharge device. The method of claim 2,
The charging and discharging driving unit further includes a driving circuit controlling the amount of current converted in the bidirectional DC-DC converter according to the charging and discharging control signal. The method of claim 3,
And a power supply unit configured to receive an AC voltage supplied from the outside and rectify the DC voltage necessary to generate the charge / discharge current in the charge / discharge driving unit. 5. The method of claim 4,
The power supply unit maintains the DC voltage constant and the secondary battery charging and discharging device to vary the amount of current according to the state of charge of the secondary battery. delete The method according to claim 1,
And a jig unit connected to the charge / discharge driving unit with a positive charge / discharge line and a negative charge / discharge line and coupled to the secondary battery. The method of claim 7, wherein
The magnetic sensor is a secondary battery charging and discharging device which is installed at a predetermined distance from any one of the positive charge and discharge line and the negative charge and discharge line. The method of claim 8,
The feedback signal is a secondary battery charging and discharging device is a current generated according to the size and direction of the magnetic field of the magnetic field. 10. The method of claim 9,
The feedback signal is a secondary battery charging and discharging device is a current of the same magnitude as the charge and discharge current. The method of claim 8,
The magnetic sensor may be at least one of a Hall element, a magnetoresistance effect (MR) element, and a Josephson device. When the secondary battery is charged, the DC voltage rectified from an externally supplied AC voltage is converted into a DC voltage for generating a charging current, and when the secondary battery is discharged, the DC voltage discharged from the secondary battery is converted into an AC voltage. Converting the DC voltage to produce;
Measuring the amount of charge and discharge current of the secondary battery by measuring magnetism generated by the charge and discharge current;
Comparing the measured charge and discharge current with a set value; And
And adjusting the charge / discharge current amount of the secondary battery according to the comparison result between the measured charge / discharge current amount and the set value. The method of claim 12,
And generating a feedback signal corresponding to the measured charge / discharge current amount. The method of claim 13,
The feedback signal is a driving method of a secondary battery charging and discharging device is a current generated according to the magnitude and direction of the magnetic field of the magnetic field. 15. The method of claim 14,
The feedback signal is a driving method of a secondary battery charging and discharging device is generated with a current amount equal to the current amount of the charge and discharge current. 15. The method of claim 14,
The method of claim 2, further comprising converting the feedback signal into a digital signal.

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