WO2004088816A1

WO2004088816A1 - Non-contact battery pack equipped with battery information processing unit

Info

Publication number: WO2004088816A1
Application number: PCT/KR2003/002685
Authority: WO
Inventors: Chun-Kil Jung; Yoon-Sang Kook
Original assignee: Hanrim Postech Co., Ltd.
Priority date: 2003-04-04
Filing date: 2003-12-08
Publication date: 2004-10-14
Also published as: KR20040087037A; AU2003304023A1; KR100505484B1

Abstract

Disclosed herein is a non-contact battery pack equipped with a battery information processing unit. The battery pack contains the secondary side of a transformer receiving power in a non-contact manner and a battery charged with the power. The non-contact battery pack includes a rectifier circuit, a charging circuit, a protection circuit and a control circuit. The rectifier circuit converts the power into direct current. The charging circuit supplies the power to the battery. The protection circuit determines the state of the battery and determines whether to supply the power to the battery. The control circuit measures voltage and current of the battery, provides information and corrects charge and discharge capacity.

Description

NON-CONTACT BATTERY PACK EQUIPPED WITH BATTERY

INFORMATION PROCESSING UNIT

Technical Field

The present invention relates generally to a non-contact battery pack equipped with a battery information processing unit and, more particularly, to a non-contact battery pack equipped with a battery information processing unit, which controls information about the spent time and remaining available time of the battery and transmits the information to a mobile terminal, so that the problems that a contact type charging method has, including undesirable charge, a reduction in the life span of the battery, a reduction in the performance of a system, the malfunction of the mobile terminal and the complete discharge of the battery, environmental pollution and economic losses can be prevented because various kinds of mobile terminals or a plurality of mobile terminals can be charged by a single charger, and the life span of the battery can be increased and the stability of performance can be secured because the battery pack controls the charge and discharge of the battery.

Background Art

In general, with the development of communications and information processing technology, the use of personal terminals, such as mobile phones, camcorders and notebook computers, which are convenient to carry, tends to gradually increase. As technology develops, new model terminals are becoming more popular.

Mobile terminals are each equipped with a small-sized battery pack on the outside of a mobile terminal or in the inside of a mobile terminal to allow the mobile terminal to be conveniently carried. A contact type charger used to charge the battery of the battery pack provides charge current to the battery pack of the mobile terminal while being in contact with a commercial power source. In order for the contact type charger to provide the charge current, the charging body of the contact type charger must be electrically comiected to the battery of the mobile terminal. The charging body and the mobile terminal are each provided with contact terminals so as to selectively connect the charging body to the battery of the mobile phone when necessary. The battery pack and the contact type charger for charging the battery pack are fabricated to fit the characteristics and appearance of the mobile terminal.

The contact type charger has the following problems that must be overcome. First, undesirable charge occurs and the life span of the battery is reduced due to the undesirable contact of the contact terminals.

Second, the performance of a system is reduced in the case where the charger or the mobile terminal is exposed to moisture or dust.

Third, the malfunction of the mobile terminal occurs due to static electricity that is produced when the contact terminals exposed to the outside come in contact with the clothes of a user and, therefore, the reliability of a product may be deteriorated.

Fourth, short circuit occurs on the contact terminals due to the carelessness of the user and, therefore, the battery can be completely discharged. Fifth, since the conventional battery pack is constructed to be charged only when the contact terminals thereof come in contact with the contact terminals of the charger, only a charger suitable for the battery pack of the mobile terminal can be used to charge the battery.

Accordingly, the user having purchased a new mobile terminal must use a specific charger suitable for the battery pack of the new mobile terminal. As a result, the user cannot use the battery pack of an old mobile terminal and an old charger, but must purchase a specific charger suitable for the new mobile terminal, thus increasing costs. Additionally, most of battery packs and chargers unfit for use must be discarded, thus causing serious environmental pollution and economic losses.

In order to solve the above-described problem, there was proposed a method of electrically connecting the battery of a mobile terminal to a charging body in a non-contact manner and charging the battery with the energy of the charging body. In this method, the primary circuit of a transformer operating at high frequency is constructed in the charging body and a secondary circuit is constructed in the battery, that is, in the mobile terminal, thus providing the current, that is, energy, of the charging body to the battery of the mobile terminal. A non-contact charging method using magnetic coupling has been applied to some application fields (for example, electrical toothbrushes and electrical razors).

Korean Unexamined Pat. Publication No. 2002-0035242 entitled "Non- contact charging apparatus for battery of mobile terminal using induction coupling" discloses the technique of charging a battery through wireless communications between a battery pack and a charging apparatus using a magnetic core. The secondary side of a transformer fabricated using the magnetic core is mounted inside of the mobile terminal. Accordingly, the non-contact charging apparatus is disadvantageous in that the size of the mobile terminal is increased and the shape of the mobile terminal is limited because the size of the magnetic core is excessively large, the mechanical strength of an application system may be reduced due to the weight of the magnetic core, and the radio frequency of a wireless communication device may influence the transformer and may reduce the reliability of the mobile terminal because the wireless communication device has to be provided to transmit information on the battery to a control and protection circuit.

In order to overcome the problems of the magnetic core, there was disclosed Korean Unexamined Pat. Publication No. 2002-0057469 entitled "Coreless ultra-thin printed circuit board transformer and non-contact battery charger using the same," which employs a transformer in which winding is formed on a Printed Circuit Board (PCB). This battery charger can overcome the problems of the magnetic core. However, this battery charger has the following problems. That is, this battery charger is problematic in that the overcharge and overheating of a battery cannot be prevented because a protection circuit is not mounted in a battery pack, so that the overcharge causes the life span of a Li-ion battery to be reduced. Additionally, most of batteries have to be completely discharged at regular intervals. However, a control and monitoring circuit monitors the voltage of the battery and provides simple information about the charge and discharge states of the battery, so that it cannot provide information about the spent time and remaining available time of the battery, thus rapidly reducing the life span of the battery.

Disclosure of the Invention

Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a non-contact battery pack equipped with a battery information processing unit, which charges a battery contained in the battery pack in a non- contact manner, controls information about the spent time and remaining available time of the battery, and transmits the information to a mobile terminal.

In order to accomplish the above object, the present invention provides a non-contact battery pack equipped with a battery information processing unit, the battery pack containing a secondary side of a transformer receiving power from a charger in a non-contact manner and a battery charged with the power supplied from the secondary side of the transformer, including a rectifier circuit for converting the power supplied from the secondary side of the transformer into direct current; a charging circuit for supplying the power converted in the rectifier circuit to the battery; a protection circuit for determining a state of the battery and determining whether to supply or cut off the power supplied from the charging circuit to the battery; and a control circuit for measuring voltage and current of the battery, providing information about spent time and charge capacity and correcting charge and discharge capacity by accumulating the provided information.

Brief Description of the Drawings

The above and other objects, features and other advantages of the present invention will be more clearly understood from the following detailed description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a block diagram of a non-contact battery pack equipped with a battery information processing unit in accordance with the present invention; FIG. 2 is an internal circuit diagram of the fuel gauge control block of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention;

FIG. 3 is a flowchart showing the information processing of the non- contact battery pack equipped with the battery information processing unit in accordance with the present invention;

FIG. 4 is a flowchart showing the charge of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention;

FIG. 5 is a charge graph for the charge of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention; and

FIG. 6 is an internal circuit diagram of the charge block of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention.

Best Mode for Carrying Out the Invention

A preferred embodiment of the present invention is described with reference to the accompanying drawings below. In the drawings, the same reference numerals are used throughout the different drawings to designate the same or similar components.

FIG. 1 is a block diagram of a non-contact battery pack equipped with a battery information processing unit in accordance with the present invention. High-frequency electromotive force induced to the secondary side winding of a transformer T contained in the battery pack is converted into direct current through the Schottky diode and hyper capacitor of a rectifier circuit 4, and the converted direct current is applied to a charging circuit 2 and charges a battery B. A charge management block having a CC/CV charging function that provides charge state and charge blocking function, Field Effect Transistors (FETs) for integrated power, a current detector and a high precision current and voltage controller, are provided in the charging circuit 2. The transformer is fabricated in a thin form, can be modified to allow the size and shape thereof to fit application devices, and is preferably made of material that is inexpensive and has high mechanical strength.

In addition, a control circuit 1 provided with a fuel gauge control block for monitoring current and voltage between battery terminals B AT+ and BAT- and between battery pack terminals PACK+ and PACK- to determine the charge and discharge states of the battery B and providing information about the state of the battery B to a mobile terminal, and a protection circuit 3 for preventing the overcharge and overheating of the battery B are provided between the battery B and the charging circuit 2.

The protection circuit 3 are comprised of a protection controller block, FETs having a switching function, resistors and a capacitor. In the case where the protection circuit 3 performs the operation of preventing overcharge, the protection circuit 3 detects the voltage of the battery B being charged, and cuts off charge current by inputting terminal CO voltage with HIGH switched to LOW if the detected voltage exceeds limit voltage (4.325 V). In the case where the protection circuit 3 performs the operation of preventing overdischarge, the protection circuit 3 detects the voltage of the battery B, and prevents discharge by outputting terminal DO voltage with HIGH switched to LOW if the detected voltage is lower than limit voltage (2.4 V).

In that case, the FET is ultra-thin SI6968EDQ, but is not limited to this.

In the case of a Li-ion battery, the present invention prevents the risks of the leakage, overheating and explosion of the battery at the time of overcharge, rapid reductions in the charge efficiency and life span of the battery at the time of overdischarge, and the serious damage of the battery at the time when excessive current is discharged due to short circuit caused by an external terminal or loader, so that the function and life span of the battery are secured by protecting the battery from an unexpected external environment and consumers are protected from the explosion of the battery.

The hyper capacitor provided in the rectifier circuit 4 is an electric double- layer capacitor. The hyper capacitor can perform high speed charge and discharge, and has a super large capacitance value. In the rectifier circuit 4, in order to convert induced electromotive force into low DC voltage, a bridge is formed of Schottky diodes and a hyper capacitor is connected in parallel, so that the available time of a mobile phone can be lengthened. In that case, the Schottky diodes are DG1H3A, but is not limited to this.

It is apparent that the construction of the rectifier circuit 4 is limited to a particular one, provided that it can achieve its purpose in the present invention.

The rectifier circuit 2 functions to charge the battery B. In the charge management block, the battery B is charged in three intervals, that is, a pre-charge interval, a constant current interval and a constant voltage interval, a charge operation is terminated by a least current, and the charge management block is provided with a charge timer (which controls operating times for operating intervals) therein so that the charge operation is stably terminated.

The battery B automatically starts to be charged when a voltage is lowered less than a lower limit value. In the case where power is not applied, a sleep mode is automatically established, thus preventing problems due to overdischarge, such as reductions in the charge efficiency and life span of the battery in the case of a Li-ion battery.

Additionally, the temperature of the battery pack is detected, and the changing and discharge of the battery B are controlled according to the detected temperature. Permission and prohibition with respect to a processor and permission to and prohibition against fast charge and the termination of charge can be controlled.

In this case, the charge current of the battery B is as follows: lout = (Vset x Kset)/Rset where lout is charge current, Vset is a charge current set voltage, and Kset is 315-355 V when lout is 50-1000 mA.

STAT1 and STAT2 are ON and OFF, respectively, during the charge of the battery B, and OFF and ON at the time of the end of charge.

The control circuit 1 provides information about the available time and capacity of the battery B. The control circuit 1 is connected in series with the battery B, monitors a voltage drop to determine the charge and discharge states of the battery B, applies temperature compensation, the amount of self-discharge and a discharge rate to a charge counter, and provides information about discharge and charge times every minute. The capacity of the battery B is automatically corrected during a discharge cycle ranging from FULL to EMPTY.

Additionally, a load of communication due to information transmission is reduced because information about charge time, discharge time, cell temperature, voltage and current is provided to a mobile terminal through one-wire bidirectional serial communications, a voltage regulator is not necessary- because an operation is performed using the power of the battery B, and a high precision voltage to frequency converter is used for charge and discharge counting.

FIG. 2 is an internal circuit diagram of the fuel gauge control block of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention. Analog data on voltage VBAT detected in the battery B and analog data on measured temperature detected in a temperature sensor unit 15 are input to a multiplexer (MUX) 14, and these data are converted into digital data through an Analog Digital Converter (ADC) 14' and thereafter stored in a temporary storage unit 12.

The temporary storage unit 12 transmits data (capacity efficiency for each battery pack, repeated capacity, a current-voltage conversion table, a charge capacity update data, etc.) and received data, along with compensation data (compensation data for the inside noise of a system), to a processing unit 11. After the processing unit 11 analyzes the transmitted data and produces information on charge capacity, charge time and life span, the processing unit 11 provides the produced information to a mobile terminal through the temporary storage unit 12 and an input/output unit 17. In that case, the temporary storage unit 12 is a Random Access Memory

(RAM). The temporary storage unit 12 is preferably an Electrically Erasable and

Programmable Read Only Memory (EEPROM) to prevent any corrections or deletions because data stored in a data storage unit 16 are basic, but is not limited to this.

The data stored in the data storage unit 16 include temperature compensation constants, discharge rate compensation constants, battery pack configuration values and charge termination taper current.

Clock signals, which determine data processing time, voltage or current detecting time, temperature detecting time and produced data transmitting time, are generated in a clock generating unit 13 and supplied to the processing unit 11, a compensation unit 12' and an analog to digital converter 14', and the clock generating unit 13 is provided with data for compensating for the change of a clock signal according to temperature from the temperature compensation unit 13'. Voltage input as VCC is supplied to a bias supply unit 18 that supplies biases, which are operating voltages, to the respective modules of an internal circuit.

FIG. 3 is a flowchart showing the information processing of the non- contact battery pack equipped with the battery information processing unit in accordance with the present invention. Average current is calculated by measuring the current of the battery B at regular intervals at step SI 01, and the voltage of the battery B and the internal temperature of the battery pack (or the temperature of the battery B) are measured at steps SI 03 and SI 04.

In that case, since the battery B is in a charge state if charge current I(CHG) is less than discharge current I(DIS), the amount of self-discharge of the battery B is calculated at step SI 06. If the number of calculations is larger than update setting time t(S) at step SI 07, data to be transmitted to a mobile terminal is produced at step S 110.

If the charge current I(CHG) is larger than the discharge current I(DIS) at step SI 05, the battery B is in a charge state, the remaining capacity of the battery B is calculated at step SI 08, full charge capacity is calculated at step SI 09, and data to be transmitted to a mobile terminal is produced at step SI 10.

In that case, for basic data used to produce the data, a table of temperature compensation constants, discharge rate compensation constants, battery pack configuration values and charge termination taper current stored in a storage medium, such as an EEPROM, is referred to.

FIG. 4 is a flowchart showing the charge of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention. FIG. 5 is a charge graph for the charge of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention. Supplied current VCC is compared with measured current VI(BAT) at step S201. The case where the measured voltage is larger than reference voltage indicates a charged state, while the case where the measured voltage is smaller than the reference voltage indicates a discharge state.

If the measured voltage is smaller than the supplied voltage, the measured voltage is compared with the reference voltage V(LOWV) at step S202. If the measured voltage is smaller than the reference voltage, a preliminary charge timer t(PRECHG) timer is operated at step S211 and a preliminary charge operation is performed at step S212.

While the preliminary charge operation is being performed, the measured voltage is repeatedly compared with the reference voltage at step S213. If the measured voltage is smaller than the reference voltage, the preliminary charge operation is continuously performed.

In that case, when the preliminary charge time t(PRECHG) elapses, the preliminary charge operation is stopped. If the measured voltage is larger than the reference voltage when the measured voltage is compared with the reference voltage at steps S202 and S213, the charge timer t(CHG) timer is operated at step S203 and a charge operation is performed at step S204.

If the charge time t(CHG) elapses while the charge operation is being performed, the charge operation is stopped. If the charge time does not elapse, the measured voltage is continuously compared with the reference time at step S206. If the measured voltage is smaller than the reference voltage, the preliminary charge operation and the charge operation are repeatedly performed.

The charge operation continues until the taper current I(TAPER) is detected at step S207 or the taper time {t(TAPER)} elapses at step S208. If the charge operation is completed, a charged state is displayed at step S209.

In FIG. 5, reference character CV represents constant voltage, CC represents constant current, RV represents regulation voltage, RI represents regulation current, and V(t) represents VI(BAT).

FIG. 6 is an internal circuit diagram of the charge block of the non-contact battery pack equipped with the battery information processing unit in accordance with the present invention. A comparison unit 22 performs comparison with respect to the measured voltage and transmits the comparison result RECHARGE, PRECHAGE, TAPER and TERM to a control unit 21. The control unit 21 transmits a control signal corresponding to the comparison result to an input/output unit 25 simultaneously with the operation of the switching unit 23.

Signals indicating charge and discharge states, which are output to the input/output unit 25, can be used as signals for controlling external elements, and activate light emitting diodes Dl and D2 to enable user to learn the charge and discharge states. The switching unit 23 functions to selectively form charge and discharge loops. A reverse blocking diode 24 is provided to prevent current, flowing the switching unit 23, from flowing through an input terminal.

Industrial Applicability

As described above, the present invention provides a non-contact battery pack equipped with a battery information processing unit, in which the problems that a contact type charging method has, including undesirable charge, a reduction in the life span of the battery, a reduction in the performance of a system, the malfunction of the mobile terminal and the complete discharge of the battery because the battery of the battery pack can be charged in non-contact manner, environmental pollution and economic losses can be prevented because various kinds of mobile terminals or a plurality of mobile terminals can be charged by a single charger, and the life span of the battery can be increased and the stability of performance can be secured because the battery pack controls information about the spent time and remaining available time of the battery, transmits the information to a mobile terminal the battery pack and controls the charge and discharge of the battery.

Although the preferred embodiments of the present invention have been disclosed for illustrative purposes, those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

Claims

1. A non-contact battery pack equipped with a battery information processing unit, the battery pack containing a secondary side (T) of a transformer receiving power from a charger in a non-contact manner and a battery (B) charged with the power supplied from the secondary side (T) of the transformer, comprising: a rectifier circuit (4) for converting the power supplied from the secondary side (T) of the transformer into direct current; a charging circuit (2) for supplying the power converted in the rectifier circuit (4) to the battery (B); a protection circuit (3) for determining a state of the battery (B) and determining whether to supply or cut off the power supplied from the charging circuit (2) to the battery (B); and a control circuit (1) for measuring voltage and current of the battery (B), providing information about spent time and charge capacity and correcting charge and discharge capacity by accumulating the provided information.

2. The non-contact battery pack according to claim 1, wherein the control circuit (1) comprises: a multiplexer (14) to which voltage detected in the battery (B) and measured temperature detected in a temperature sensor unit (15) are input; an analog to digital converter (14') for converting signals output from the multiplexer (14) into digital signals; a compensation unit (12') for compensating for the voltage detected in the battery (B); a data storage unit (16) for storing data including temperature compensation constants, discharge rate compensation constants, battery pack configuration values and charge termination taper current; a temporary storage unit (12) for receiving signals output from the analog to digital converter (14') and the data stored in the data storage unit (16); a processing unit (11) for receiving and analyzing the data received by the temporary storage unit (12), producing data on charge capacity, charge time and life span, and retransmitting the produced data to the temporary storage unit (12); an input/output unit (17) for transmitting the data produced in the processing unit (11) and transmitted to the . temporary storage unit (12) to an outside of the battery pack; a clock generating unit (13) for generating clock signals for determining data processing time, voltage or current detecting time, temperature detecting time and produced data transmitting time, and supplying the clock signals to the processing unit (11), the compensation unit (12') and the analog to digital converter (14'); a temperature compensation unit (13') for compensating for change of the clock signals generated in the clock generating unit (13) due to change of temperature; and a bias supply unit (18) for supplying biases, which are operational voltages, to respective modules of an internal circuit.

3. The non-contact battery pack according to claim 1, wherein the charging circuit (2) comprises: a comparison unit for receiving charged voltage, comparing the charged voltage with reference voltage, and outputting a control signal determining a charge or discharge operation; a control unit (21) for receiving the control signal output from the comparison unit (22) and outputting a control signal according to the charge or discharge operation; a switching unit (23) for receiving the control signal from the control unit

(21) and selectively forming charge and discharge loops; an input/output unit (25) for receiving the control signal from the control unit (21) and indicating a charge or discharge state; and a reverse blocking diode (24) installed in the switching unit (23) to prevent current from flowing through an input terminal.