WO2006115342A1 - Circuit and chip for protecting battery, method of manufacturing the same and battery pack having the same - Google Patents

Circuit and chip for protecting battery, method of manufacturing the same and battery pack having the same Download PDF

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Publication number
WO2006115342A1
WO2006115342A1 PCT/KR2006/001287 KR2006001287W WO2006115342A1 WO 2006115342 A1 WO2006115342 A1 WO 2006115342A1 KR 2006001287 W KR2006001287 W KR 2006001287W WO 2006115342 A1 WO2006115342 A1 WO 2006115342A1
Authority
WO
WIPO (PCT)
Prior art keywords
battery
voltage
resistor
transistor
external electrode
Prior art date
Application number
PCT/KR2006/001287
Other languages
French (fr)
Inventor
Woo Sik Um
Young Keun Chung
Bong Jun Kim
Original Assignee
U-Nisum Technology Co., Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from KR1020050029414A external-priority patent/KR100782101B1/en
Priority claimed from KR1020050072305A external-priority patent/KR100728812B1/en
Application filed by U-Nisum Technology Co., Ltd filed Critical U-Nisum Technology Co., Ltd
Priority to CN2006800114114A priority Critical patent/CN101164216B/en
Publication of WO2006115342A1 publication Critical patent/WO2006115342A1/en

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Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/44Methods for charging or discharging
    • H01M10/443Methods for charging or discharging in response to temperature
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • H01M10/486Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte for measuring temperature
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/42Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/425Structural combination with electronic components, e.g. electronic circuits integrated to the outside of the casing
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/60Heating or cooling; Temperature control
    • H01M10/61Types of temperature control
    • H01M10/613Cooling or keeping cold
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00Secondary cells; Manufacture thereof
    • H01M10/60Heating or cooling; Temperature control
    • H01M10/63Control systems
    • H01M10/637Control systems characterised by the use of reversible temperature-sensitive devices, e.g. NTC, PTC or bimetal devices; characterised by control of the internal current flowing through the cells, e.g. by switching
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2200/00Safety devices for primary or secondary batteries
    • H01M2200/10Temperature sensitive devices
    • H01M2200/105NTC
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2200/00Safety devices for primary or secondary batteries
    • H01M2200/10Temperature sensitive devices
    • H01M2200/106PTC
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01MPROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M2200/00Safety devices for primary or secondary batteries
    • H01M2200/10Temperature sensitive devices
    • H01M2200/108Normal resistors
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02EREDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10Energy storage using batteries

Definitions

  • the present invention relates to a protection circuit and a battery pack having the same, and more particularly, to a battery pack having a protection device capable of protecting a battery against overcharge and overcurrent and ensuring thermal stability under all the conditions of use of the battery.
  • a battery comprises positive and negative electrode plates and electrolyte and refers to a device for generating direct current electromotive force through a chemical reaction to use the generated force as electrical power.
  • chemical energy of a chemical material contained therein is converted to electrical energy through an electrochemical oxidation-reduction reaction.
  • the battery may be classified into a primary battery that cannot be recharged after use and a secondary battery that can be recharged and reused when its voltage drops below to a predetermined voltage range.
  • the aforementioned battery will be operated, as follows.
  • the negative electrode of the battery is made of a material that is oxidized by losing electrons, whereas the positive electrode is made of a material that is reduced by accepting electrons.
  • an external device e.g., a lamp or an electronic appliance
  • two electrodes are changed into electrochemically different states, respectively.
  • electrical circuitry is formed in the electrolyte by means of the mass transfer of anions and cations toward the negative and positive electrodes.
  • a primary battery cannot be recharged because a reverse reaction is not produced, whereas a secondary battery can be charged and returned to an original chemical state.
  • a secondary battery can be reused and easily manufactured to have a small size and weight.
  • oxygen gas may be generated at the positive electrode, a lithium metal may be deposited on the negative electrode, and the electrolyte may be decomposed into gas.
  • these continued reactions may lead to explosion or fire.
  • the temperature in a lithium battery (lithium-ion battery or lithium-polymer battery), which is used as a secondary battery rapidly rises due to the external mechanical impact, the change in thermal environment, the electrical connection and the like caused by instable materials of the battery, so that the expansion, explosion and the like of the battery are produced.
  • a protection circuit such as a protection circuit module (PCM) is employed in most of the secondary batteries.
  • PCM protection circuit module
  • the PCM is used to perform the functions of protecting the battery against the overcurrent, the overcharge, overdischarge, and short circuit when the battery is charged.
  • the PCM is composed of active elements such as an integrated circuit (IC) or field effect transistor (FET), and passive elements such as a resistor and capacitor.
  • Korean Patent Laid-Open Publication No. 10-2004-13354 In Korean Patent No. 10-301346, a PCM with an integrated circuit is used to protect a secondary battery, but the integrated circuit is expensive and complex. Further, in Korean Patent Laid-Open Publication No.10-2004-13354, a PCM with a plurality of sensors and a discharging unit is used to protect a secondary battery. That is, a control unit controls a protection c ircuit and a charging/discharging unit based on a value inputted from a voltage or temperature sensor. In this case, the production costs are increased due to the use of the voltage or temperature sensor, and the circuit becomes complicated since the discharging unit should discharge the overcurrent based on the value inputted from the sensor. In a case where this battery is to be actually implemented, the total production costs of the battery are increased.
  • a temperature sensing device in which an overcurrent blocking element or a PTC (positive temperature coefficient) element is connected in series with an NTC (negative temperature coefficient) element prevents the overcurrent from flowing into the NTC element such that the NTC element cannot be damaged.
  • the temperature sensing device of the patent is only to protect the NTC element when a temperature sensing terminal with the NTC element connected thereto is connected with a hot-side terminal.
  • the temperature sensing device cannot be directly used to control the secondary battery.
  • Additional FET and adjuster IC are essentially used to detect the change of the NTC element and to protect the secondary battery.
  • the circuit is complicated and the production costs of the secondary battery are increased as described above.
  • the PCM is a circuit formed with active and passive elements as previously described, the characteristic variations between individual elements has an effect on overall circuit characteristics. For example, packaged transistors have different operation voltages. Even though the packaged transistors are manufactured from the same wafer, they have a minor difference in their operation voltages. Furthermore, the NTC elements exhibit different changes in temperature-dependent resistance. Therefore, if such a plurality of PCM circuits are manufactured using these circuit elements and mounted for the purpose of battery protection, the variation between the individual circuit elements leads to characteristic variations between the PCM circuits. Accordingly, since some of the PCM circuits do not operate under a desired condition, the life span of the battery may be shortened and the performance thereof can also be deteriorated. In addition, the expansion or explosion of the battery cannot be prevented. Disclosure of Invention Technical Problem
  • an object of the present invention is to provide a battery protection circuit and chip capable of simplifying a control module including a temperature sensor and a switching device operating with a predetermined voltage change into a single chip to thereby significantly reduce its production costs, of preventing the overcharge, controlling the overcurrent and ensuring the thermal stability, of adjusting characteristic variations between a plurality of control modules within a certain range for their mass production, and of preventing the malfunction and failure of the control module; a method of manufacturing the same; and a battery pack having the same.
  • a battery protection chip comprising first and second external electrode terminals; a switching unit for selectively connecting the first and second external electrode terminals according to a control voltage; a control voltage generator for dividing a voltage between the first and second external electrode terminals according to a temperature to generate the control voltage; and a body for packaging the switching unit and the control voltage generator.
  • the switching unit includes a transistor which has a collector and an emitter connected to the first and second external electrode terminals, respectively, and operates according to the control voltage.
  • the battery protection chip may further comprise a resistor connected between the first external electrode terminal and the collector of the transistor or between the second external electrode terminal and the emitter of the transistor, wherein the resistor is connected to the first or second external electrode terminal.
  • the control voltage generator comprises a first voltage dividing means connected between the first external electrode terminal and a control voltage node; and a second voltage dividing means connected between the second external electrode terminal and the control voltage node.
  • each of the first and second voltage dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a voltage dividing resistor element, a varistor, and a Zener diode, each having a temperature-dependent resistance characteristic.
  • a method of manufacturing a battery protection chip comprising the steps of (a) providing a switching device, a voltage dividing element, and first and second external electrode terminals; (b) electrically connecting and packaging the switching device, the voltage dividing element and the first and second external electrode terminals with one another such that a voltage between the first and second external electrode terminals is divided according to a temperature and the first and second external electrode terminals is selectively connected with each other according to the divided voltage; and (c) testing the packaged and electrically connected circuit elements to detect failure.
  • the switching device is a transistor and the voltage dividing element is at least one selected from the group consisting of an NTC element, a PTC element and a voltage dividing resistor element, each having a temperature-dependent resistance characteristic.
  • the step (b) comprises the steps of connecting the voltage dividing element and the switching device between the first and second external electrode terminals through wires and connecting one end of the voltage dividing element and the switching device through a wire; and packaging the voltage dividing element and the switching device.
  • the step (b) comprises the steps of preparing upper and lower bodies; arranging the switching device and the voltage dividing element within the lower body and disposing first and second external electrode terminals onto both ends of the lower body, respectively; connecting the switching device, the voltage dividing element and the first and second external electrode terminals through wires; and sealingly coupling the upper body onto the lower body with the wire-connected switching device and voltage dividing element arranged thereon.
  • the step (b) comprises the steps of preparing upper and lower bodies; forming pads to be connected with the switching device and the voltage dividing element on the lower body and then electrically connecting the pads; connecting the switching device and the voltage dividing element to the pads to be electrically connected to the first and second external electrode terminals; and coupling the upper body onto the lower body to package the switching device and the voltage dividing element.
  • a battery pack comprising a battery body having positive and negative electrodes; and a battery protection chip operating to selectively connect the positive and negative electrodes according to a temperature.
  • a battery pack comprising a battery body having positive and negative electrodes; a voltage dividing means for dividing a voltage from the battery body; and a control module including a switching means operating to establish a current path between the positive and negative electrodes according to the voltage divided by the voltage dividing means.
  • the voltage dividing means comprises at least two dividing means between the positive and negative electrodes connected in series with each other, and the dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a varistor, a Zener diode, a dividing resistor element.
  • the switching means includes a transistor which has a collector connected to the positive electrode and an emitter connected to the negative electrode and operates with the voltage dividing means.
  • the battery pack of the present invention may further comprises a current control resistor connected between the emitter of the transistor and the negative electrode or between a collector of the transistor and the positive electrode; and a temperature control switch brought into physical contact with the current control resistor to control a current path through the negative or positive electrode.
  • a battery pack comprising: a battery body having positive and negative electrodes; and a PTC element and a heating element connected in parallel with each other on the positive electrode.
  • control module is composed of a voltage dividing means and a switching means, the circuit thereof can be simplified. [30] Furthermore, the production costs can be significantly reduced by simplifying a control module including a temperature sensor and a switching device operating with a predetermined voltage change into a single chip. [31] In addition, since characteristic variations between a plurality of battery protection chips can be adjusted within a certain range, it is possible to mass produce the chips and to prevent the malfunction and failure of the chips.
  • Fig. 1 is a conceptual diagram of a battery pack according to a first embodiment of the present invention.
  • Fig. 2 is a graph illustrating a temperature-resistance characteristic of an NTC element.
  • Fig. 3 is a graph illustrating a temperature-resistance characteristic of a PTC element.
  • Figs. 4 to 6 are conceptual diagrams illustrating the arrangement of a control module according to a first embodiment of the present invention.
  • Fig. 7 is a conceptual diagram of a battery pack according to a second embodiment of the present invention.
  • Figs. 8 and 9 are conceptual diagrams illustrating a battery pack according to a third embodiment of the present invention.
  • Figs. 1 is a conceptual diagram of a battery pack according to a first embodiment of the present invention.
  • Fig. 2 is a graph illustrating a temperature-resistance characteristic of an NTC element.
  • Fig. 3 is a graph illustrating a temperature-resistance characteristic of a PTC element.
  • FIG. 10 and 11 are conceptual diagrams illustrating a battery pack according to a fourth embodiment of the present invention.
  • Fig. 12 is a conceptual diagram illustrating a battery pack according to a fifth embodiment of the present invention.
  • Fig. 13 is a conceptual diagram illustrating a battery pack according to a sixth embodiment of the present invention.
  • Fig. 14 is a conceptual diagram illustrating a battery pack according to a seventh embodiment of the present invention.
  • Fig. 15 is a conceptual diagram of a battery protection chip according to the seventh embodiment of the present invention.
  • Figs. 16 to 18 are views illustrating processes of manufacturing the battery protection chip according to the seventh embodiment of the present invention.
  • Fig. 19 is a conceptual diagram of a battery pack according to a first modification of the seventh embodiment of the present invention.
  • Fig. 20 is a conceptual diagram of a battery pack according to a second modification of the seventh embodiment of the present invention.
  • Figs. 21 and 22 are conceptual diagrams of a battery pack according to a third mod- ification of the seventh embodiment of the present invention.
  • FIGs. 23 and 24 are conceptual diagrams of a battery pack according to a fourth modification of the seventh embodiment of the present invention.
  • FIG. 25 is a conceptual diagram of a battery pack according to a fifth modification of the seventh embodiment of the present invention. Best Mode for Carrying Out the Invention
  • FIG. 1 is a conceptual diagram of a battery pack according to a first embodiment of the present invention.
  • a battery pack 100 includes a battery body 10 having positive and negative electrodes 11 and 12, and a control module 20 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature.
  • the battery pack 100 may further include a PTC element 30 connected to the negative electrode 12 to block external current according to the temperature.
  • the battery may be any battery including a secondary battery or a fuel cell.
  • the secondary battery may be a lead-acid battery, an alkaline battery, a gas battery, a lithium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a polymer battery or the like.
  • a small-sized secondary battery has been shifted from a nickel- cadmium battery to a nickel-hydrogen battery and a lithium-ion battery.
  • a lithium polymer battery has been used which is obtained by replacing an electrolyte with a polymer in the lithium-ion battery.
  • the fuel cell may be a molten carbonate fuel cell using an alkaline solution as an electrolyte, a solid electrolyte fuel cell, a phosphoric acid electrolyte fuel cell or the like.
  • the electrolyte may be pure hydrogen and oxygen.
  • the electrolyte may be gas fuel using fossil fuel such as methane and natural gas other than hydrogen or may be liquid fuel such as methanol and hydrazine.
  • the control module 20 includes a transistor 22 with a collector connected to the positive electrode, an NTC element 21 connected between a base of the transistor 22 and the positive electrode 11, a first resistor 23 connected between the base of the transistor 22 and the negative electrode 12, and a second resistor 24 connected between an emitter of the transistor 22 and the negative electrode 12.
  • the first resistor 23 may be connected between the base and emitter of the transistor.
  • An additional capacitor may be provided between the positive and negative electrodes 11 and 12.
  • the battery pack 100 may further include a capacitor connected in parallel with the NTC element 21.
  • the battery pack 100 may further include a capacitor connected in parallel with the first resistor 23.
  • an NPN transistor is used as the transistor 22.
  • a turn-on voltage of the transistor is within a range of 0.3 to 0.7V
  • the first resistor 23 has a resistance of 0.5 to 2D
  • the second resistor 24 has a resistance of 10 to 50 ⁇ .
  • a PNP transistor may be used as the transistor 22.
  • a digital transistor with the transistor 22 and the first resistor 23 integrated into a single chip may be employed.
  • the transistor 22 may be a BJT or MOS transistor. Characteristics of the individual elements constituting the control module 20 of the present invention are not limited to the aforementioned values but may be variously changed according to voltage and current generated in the battery body. That is, an NTC or PTC element may be used as the first resistor 23, whereas a resistor may be substituted for the NTC element 21.
  • Fig. 2 is a graph illustrating a temperature-resistance characteristic of an NTC element
  • Fig. 3 is a graph illustrating a temperature-resistance characteristic of a PTC element.
  • the resistance of the NTC element 21 decreases nonlinearly as the temperature rises.
  • the resistance of the NTC element 21 is about IOOD at room temperature but decreases rapidly to about 7.4D at a temperature of 100 0 C.
  • the NTC element 21 preferably has a resistance of 90 to 150D at a temperature of 18 to 3O 0 C and a resistance of 4 to 1OD at a temperature of 90 to 12O 0 C.
  • the characteristic of the NTC element of the present invention is not limited thereto, but the characteristic values of the NTC element may be changed according to characteristics of the first resistor and the transistor.
  • the PTC element 30 is an element of which resistance is maintained constant at a given temperature but rapidly increases when a temperature exceeds a certain value. That is, the PTC element 30 has a resistance of a few to several tens ohms at room temperature. However, when a temperature exceeds a given temperature, the PTC element 30 has a resistance of several hundreds ohms enough to substantially operate as a nonconductor. [59] In this embodiment, the PTC element 30 is disposed on the negative electrode 12 to control the negative electrode to be short-circuited according to the temperature.
  • a first negative electrode extending from the battery body is connected to one terminal of the PTC element 30, and a second negative electrode exposed to the outside of the battery pack is connected to the other terminal of the PTC element 30.
  • the PTC element 30 is preferably brought into physical contact with the second resistor 24. Accordingly, if the battery temperature is increased when the battery is charged, the second resistor 24 is heated and the PTC element 30 brought into physical contact with the second resistor 24 is also heated, so that the external current can be blocked.
  • the second resistor 24 is preferably manufactured to have a maximum physical contact area with the PTC element 30. That is, the second resistor 24 is preferably formed into a plate shape to come into contact with top, side and bottom surfaces of the PTC element 30.
  • the transistor 22 will be turned off.
  • the predetermined temperature may be an additionally set temperature or a temperature immediately before the battery pack 100 explodes.
  • the temperature can be set by adjusting the characteristic of the NTC element 21, the driving voltage of the transistor 22 or the resistance of the first resistor 23.
  • the predetermined temperature is set to 100 0 C and that the control module 20 starts to operate at this temperature.
  • the resistance of the NTC element 21 drops to about 7.4D and a voltage of 3.7V is applied across the NTC element 21.
  • a voltage (operation voltage) of 0.5V is applied across the first resistor 23 and the transistor 22 is then turned on. That is, a path along which the transistor 22 and the second resistor 24 are connected in series with each other is established between the positive and negative electrodes 11 and 12.
  • the battery is electrically short-circuited and the battery is changed from a high energy state to a low energy state to thereby prevent the battery from being expanded and exploded.
  • the transistor 22 is turned on, electrical current flows rapidly from the battery but is suppressed by the second resistor 24.
  • control module 20 operates to cause the battery to be forcibly discharged such that the battery is in a low energy state to thereby prevent the battery from being expanded and exploded.
  • the present invention is not limited thereto. That is, a variety of elements with temperature-dependent resistance may be used.
  • the element with temperature-dependent resistance may be a PTC, a CTR or the like.
  • the element is not limited to the transistor, but a variety of elements for performing switching operation according to the voltage change may be used. That is, in this embodiment, a transistor serving as a switching device is controlled to be turned on and off according to the voltage division by a resistance difference between the NTC element and the first resistor. Therefore, an element of which resistance decreases as the temperature rises is preferably used as the NTC element, while an element of which resistance increases as the temperature rises is preferably used as the first resistor.
  • FIGs. 4 to 6 are conceptual diagrams illustrating the arrangement of the control module according to the first embodiment of the present invention.
  • the control module 20 of the present invention is preferably arranged between the internal positive/negative electrodes of the battery body 10 and the positive/negative electrodes 11 and 12 of the battery pack 100. As shown in Fig. 4, the control module 20 may be disposed in a given area of a PCM panel 40 which includes an active element such as a microprocessor or FET and some passive elements to perform the functions of protecting the battery against the overcurrent, overcharge, overdischarge, and short circuit when the battery body 10 is charged.
  • an active element such as a microprocessor or FET and some passive elements to perform the functions of protecting the battery against the overcurrent, overcharge, overdischarge, and short circuit when the battery body 10 is charged.
  • the NTC 21, the transistor 22 and the resistors 23 and 24 are disposed in an empty space of a printed circuit board for the PCM 40 and then electrically connected to one another such that the battery protection function of the PCM 40 can be provided and the explosion of the battery pack due to heating can also be prevented.
  • an individual control module panel 20 is formed to include the aforementioned control circuit therein and then arranged between the positive and negative electrodes 11 and 12.
  • the battery pack 100 may further include the PCM panel 40.
  • only the individual control module panel 20 may be provided in the battery pack 100.
  • control module 20 can be brought into contact with a portion of the battery body to immediately sense the temperature change of the battery body 10. That is, the control module 20 is mounted on the printed circuit board or they are connected with each other using a separate wire as described above, and the NTC element 21 is then brought into physical contact with the battery body 10.
  • the control module 20 can be operated sensitively according to the temperature change of the battery body 10, a more stable battery pack 100 can be obtained.
  • the control module into which the aforementioned structures of Figs. 4 to 6 are combined may be arranged in the battery pack 100 of the present invention.
  • the battery pack of the present invention may include a control circuit capable of protecting the battery against the overcharge and overcurrent and ensuring the thermal stability.
  • a second embodiment of the present invention will be described with reference to the accompanying drawing. A description of the second embodiment which overlaps that of the first embodiment will be omitted herein. The second embodiment may be applied to the first embodiment.
  • Fig. 7 is a conceptual diagram of a battery pack according to the second embodiment of the present invention.
  • the battery pack 100 includes a battery body 10 which has positive and negative electrodes 11 and 12 and can be charged and discharged, a control module 120 for connecting the positive and negative electrodes 11 and 12 according to a change in current and/or voltage from the battery body 10, and a PTC element 130 which is physically connected to a portion of the control module 120 to block an external current according to the temperature.
  • the aforementioned control module 120 includes a transistor 122 with a collector connected to the positive electrode 11, a first resistor 121 connected between a base of the transistor 122 and the positive electrode 11, a second resistor 123 connected between the base and emitter of the transistor 122, and a third resistor 124 connected between the emitter of the transistor 122 and the negative electrode 12.
  • an NPN transistor is used as the transistor 122.
  • a turn-on voltage of the transistor is within a range of 0.3 to 0.7V
  • the first resistor 121 has a resistance of 250 to 350D
  • the second resistor 123 has a resistance of 10 to 9OD
  • the third resistor 124 has a resistance of 10 to 50 ⁇ .
  • Characteristics of the individual elements constituting the control module 120 of this embodiment are not limited to the aforementioned values but may be variously changed according to voltage and current of the battery body 10 when the battery body 10 is charged.
  • the first resistor of this embodiment may be an element such as a varistor (chip varistor) or a Zener diode of which resistance is rapidly changed according to the voltage applied thereto instead of an element with the constant resistance.
  • the transistor 122 Since the transistor 122 is turned on, a current path is established between the positive and negative electrodes 11 and 12 of the battery pack 100 to cause the battery body 10 to be forcibly discharged. In this manner, the battery current is discharged to drop the battery voltage. At this time, if the transistor 122 is turned on, the third resistor 124 controls the rapid current flow. Further, since the temperature of the third resistor 124 rapidly rises, the resistance of the PTC element 130 physically contact to the third resistor 124 also increases rapidly to block the current path toward the terminal of the external charger 200 such that the battery cannot be charged any longer.
  • the voltage of the battery pack 100 is 4.3V or less due to the normal charge, it is divided by the first, second and third resistors 121, 123 and 124 such that a voltage of 3.799V or less is applied across the first resistor 121, a voltage of 0.499V or less is applied across the second resistor 123, and a voltage of 0.0003V or less is applied across the third resistor 124. That is, since a voltage of 0.5V or less is applied across the second resistor 123 connected between the emitter and base of the transistor 122, the transistor 122 is turned off.
  • control module of the present invention may be configured as a single module into which the control modules according to the first and second embodiments are combined.
  • a third embodiment of the present invention will be described with reference to the accompanying drawings. A description of the third embodiment which overlaps those of the first and second embodiments will be omitted herein. The third embodiment may be applied to the first and second embodiments.
  • FIGs. 8 and 9 are conceptual diagrams illustrating a battery pack according to the third embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a first transistor 222 for dividing a voltage of the battery pack 100 by a first resistor 223 and an NTC element 221 of which resistance varies with the temperature of the battery body 10 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, a second transistor 226 for dividing the voltage of the battery pack 100 by third and fourth resistors 225 and 227 and then establishing a current path between the positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, second and fifth resistors 224 and 228 connected respectively between the first transistor 222 and the negative electrode 12 and between the second transistor 226 and the negative electrode 12, and a PTC element 210 physically connected to the second and fifth resistors 224 and 228 to control current flowing through the negative electrode 12.
  • the second and fifth resistors 224 and 228 may be replaced with a single resistor. That is, as shown in Fig. 9, a sixth resistor 229 may be connected between the bases of the first and second transistors 222 and 226 and the negative electrode 12.
  • the module capable of protecting the battery against the overcharge and overcurrent in the battery pack and the module capable of ensuring the thermal stability of battery can be manufactured into a single package or separate package.
  • the battery stability can be enhanced and the production costs of the battery pack can also be reduced as compared to a conventional PCM module.
  • the circuit for ensuring the thermal stability and the circuit for protecting the battery against the overcharge and overcurrent may be incorporated into a single switching device.
  • a fourth embodiment of the present invention will be described with reference to the accompanying drawings. A description of the fourth embodiment which overlaps those of the first to third embodiments will be omitted herein. The fourth embodiment may be applied to the first to third embodiments.
  • FIGs. 10 and 11 are conceptual diagrams illustrating a battery pack according to the fourth embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a transistor 325 for dividing a voltage of the battery pack 100 according to a parallel resistance value of a first resistor 322 and an NTC element 321 of which resistance varies with the temperature of the battery body 10 and a parallel resistance value of a second resistor 323 and a third resistor 324 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage.
  • the battery pack of this embodiment may further include a resistor which is connected between a base of the transistor 325 and the negative terminal 12 and a PTC element which is physically connected to the resistor to control the current flowing through the negative terminal.
  • the second and third resistors 323 and 324 may be replaced with a single resistor.
  • a single resistor having a parallel resistance value of the second and third resistors 323 and 324 may be employed.
  • the transistor 325 operates through the voltage division between the positive and negative electrodes 11 and 12 according to the parallel resistance value of the NTC element 321 and the first resistor 322 and the parallel resistance value of the second and third resistors 323 and 324. That is, as previously described in the second embodiment, since a voltage sufficient to turn on the transistor 325 is not applied across the second and third resistors 323 and 324 in a normal voltage state, the battery body 10 can be freely charged and discharged.
  • a voltage sufficient to turn on the transistor 325 is applied across the second and third resistors 323 and 324, the transistor 325 is turned on such that a current path is forcibly established between the positive and negative electrodes 11 and 12 to thereby prevent the overcharge and overcurrent.
  • the resistance of the NTC element 321 rapidly decreases such that the parallel resistance value of the NTC element 321 and the first resistor 322 decreases. Accordingly, a voltage sufficient to turn on the transistor 325 is applied across the second and third resistors 323 and 324 such that the current path can be forcibly established between the positive and negative electrodes 11 and 12 of the battery to thereby prevent the explosion of the battery.
  • the PTC element may be arranged on the positive terminal. That is, the
  • PTC element may be arranged not only on the negative terminal of the battery body but also on the positive terminal to control the current flowing through the positive terminal.
  • FIG. 12 is a conceptual diagram illustrating a battery pack according to the fifth embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a transistor
  • a voltage of the battery pack 100 for dividing a voltage of the battery pack 100 by a first resistor 423 and an NTC element 421 of which resistance varies with the temperature of the battery body 10 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, a second resistor 424 connected between a collector of the transistor 422 and the positive electrode 11, and a PTC element 410 physically connected to the second resistor 424 to control the current flowing through the positive electrode 11.
  • the PTC element 410 is arranged on the positive electrode 11 to allow the battery to be electrically disconnected from the external circuit when the overheating/overcharge/overcurrent are produced in the battery.
  • the battery can be electrically disconnected from the external circuit only by the PTC element and the heating element.
  • Such a sixth embodiment of the present invention will be described with reference to the accompanying drawing. A description of the sixth embodiment which overlaps those of the aforementioned first to fifth embodiments will be omitted herein. The sixth embodiment may be applied to the first to fifth embodiments.
  • FIG. 13 is a conceptual diagram illustrating a battery pack according to the sixth embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a battery body
  • the PTC element 510 and the resistor 521 may be connected in parallel with each other on a negative electrode 12.
  • the PTC element 510 and the resistor 521 may be connected in parallel with each other on both the positive and negative electrodes 11 and 12.
  • the resistor 521 and the PTC element 510 are physically connected with each other. That is, when the current flowing into the positive electrode 11 and/or the negative electrode 12 of the battery increases due to external factors, the resistor 521 is heated and the temperature thereof increases. If the temperature of the resistor 521 exceeds a predetermined temperature, the resistance of the PTC element 510 increases to cause the positive electrode 11 and/or negative electrode 12 to be electrically short- circuited. Of course, the battery pack 100 may be heated to change the resistance of the PTC element 510 such that both terminals can be short-circuited.
  • the resistance of the PTC element 510 again decreases and thus the battery can operate in a normal state.
  • the control module is not limited to the use in the battery pack according to the previous embodiments but may be arrange between input and output ends of a given circuit to prevent the circuit from being overheated or undergoing the extraordinary change in input power and thus to perform the stable circuit operation. In other words, it is possible to ensure the circuitry stability against the thermal change by installing the control module in electronic equipment such as a camcorder, a cellular phone or a computer.
  • Fig. 14 is a conceptual diagram illustrating a battery pack according to the seventh embodiment of the present invention
  • Fig. 15 is a conceptual diagram of a battery protection chip according to the seventh embodiment of the present invention.
  • a battery pack 100 includes a battery body 10 having positive and negative electrodes 11 and 12, and a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature.
  • the battery pack 100 may further include a PTC element (not shown) connected to the negative electrode 12 to block external current according to the temperature.
  • the battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200, a switching unit 2300 for electrically connecting the first and second external electrode terminals 2100 and 2200 in response to a control voltage, a control voltage generator 2400 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 according to the temperature to generate the control voltage, and a body 2500 for packaging the switching unit 2300 and the control voltage generator 2400.
  • a transistor 2310 is used in the switching unit 2300.
  • the control voltage generator 2400 includes an NTC element 2420 connected between the first external electrode terminal 2100 and a control voltage node Ql and having temperature-dependent resistance, and a resistor 2440 connected between the second external electrode terminal 2200 and the control voltage node Ql.
  • the transistor 2310 serving as the switching unit 2300 has a collector connected to the first external electrode terminal 2100, a base connected to the control voltage node Ql between the NTC element 2420 and the resistor 2440, and an emitter connected to the second external electrode terminal 2200.
  • the aforementioned battery protection chip 2000 operates at a temperature of 70 to 100 0 C to have a current of about ImA to 2OA.
  • the battery protection chip 2000 does not operate when the internal temperature of the battery pack 100 is lower than the temperature within the operation range. If the internal temperature of the battery rapidly rises to the operation temperature range due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, however, a current path from the first external electrode terminal 2100 to the second external electrode terminal 2200 is established to thereby prevent the overcharge, control the overcurrent and ensure the thermal stability.
  • an operation time point of the switching device when the current path is established between the positive and negative terminals of the battery using the voltage division between the fixed resistor and the variable resistor whose resistance varies with the temperature of the battery pack is controlled to protect the battery pack.
  • a portion of the body of the battery protection chip 2000 is brought contact with the battery body 10 such that a temperature change in the battery body 10 can be immediately sensed.
  • the characteristics of the respective elements constituting the battery protection chip 2000 of the present invention are not limited to the aforementioned value, and the value may be variously changed according to the voltage and current generated in the battery body 10.
  • the aforementioned battery protection chip may be fabricated in various ways.
  • Figs. 16 to 18 illustrate processes of manufacturing the battery protection chip according to the seventh embodiment of the present invention.
  • a transistor 2310, an NTC element 2420 and a resistor 2440 are prepared.
  • the transistor 2310 is a bare chip element that is not wire bonded. That is, a transistor 2310 in which additional electrodes for connecting a base, an emitter and a collector of the transistor to the outside are not formed and the base, emitter and collector of the transistor are directly exposed to the outside is used.
  • the NTC element 2420 and the resistor 2440 are chip type elements.
  • a first external electrode terminal 2100 is connected to one terminal of the NTC element 2420, and a second external electrode terminal 2200 is connected to one terminal of the resistor 2440.
  • the transistor 2310, the NTC element 2420 and the resistor 2440 are connected to each other using wires 2301 to 2304.
  • the collector of the transistor 2310 and the one terminal of the NTC element 2420 connected to the first external electrode terminal 2100 are connected through the first wire 2301.
  • the base of the transistor 2310 and the other terminal of the NTC element 2420 are connected through the second wire 2302, and the base of the transistor 2310 and the terminal of the resistor 2440 are connected through the third wire 2303.
  • the emitter of the transistor 2310 and the one terminal of the resistor 2440 connected to the second external electrode terminal 2200 are connected through the fourth wire 2304.
  • a predetermined packaging process of manufacturing the battery protection chip 2000 is performed by forming the body 2500 for protecting the transistor 2310, the NTC element 2420 and the resistor 2440.
  • the transistor 2310, the NTC element 2420 and the resistor 2440 connected to each other through wires are disposed at the center of a given frame, portions of the first and second external electrode terminals 2100 and 2200 are exposed to the outside of the frame, and a liquefied epoxy or plastic material is poured into the frame and then cured to manufacture the body 2500. That is, the body 2500 may be manufactured by using any one of positive, flash, injection and semi-positive molds.
  • the body 2500 may be manufactured into an upper body and a lower body. Such a modification will be described with reference to the accompanying drawings. A description of the modification of this embodiment which overlaps those of the previous embodiments will be omitted herein.
  • the transistor 2310, the NTC element 2420 and the resistor 2440 are connected to one another through the wires 2301, 2302, 2303 and 2304 to form a predetermined protection circuit.
  • the collector of the transistor 2310 is connected to the one terminal of the NTC element 2420 through the first wire 2301
  • the emitter of the transistor 2310 is connected to the one terminal of the resistor 2440 through the fourth wire 2304
  • the other terminal of the NTC element 2420 is connected to the other terminal of the resistor 2440 through the second wire 2302
  • the second wire 2302 is connected to the base of the transistor 2310 through the third wire 2303.
  • the transistor 2310, the NTC element 2420 and the resistor 2440 connected through the wires 2301, 2302, 2303 and 2304 are disposed on the lower body 2510 and then connected to the first and second external electrode terminals 2100 and 2200.
  • the first wire 2301 is connected to the first external electrode terminal 2100 through a fifth wire 2305
  • the fourth wire 2304 is connected to the second external electrode terminal 2200 through a sixth wire 2306.
  • the first and second external electrode terminals 2100 and 2200 extend to bend from a top surface of the lower body.
  • the upper body 2520 is coupled onto the top surface of the lower body 2510 on which the transistor 2310, the NTC element 2420 and the resistor 2440 are formed, to thereby complete the battery protection chip 2000.
  • the battery protection chip of the present invention is not limited thereto, and it may be manufactured in various ways. That is, the transistor 2310, the NTC element 2420 and the resistor 2440 may be disposed on the lower body 2510, connected to one another through the wires or metal lines, connected to the first and second external electrode terminals, and then covered with the upper body for the packaging.
  • the transistor, the NTC element and the resistor may be connected to one another through additional pads and metal lines.
  • a bump may be used as the pad.
  • the transistor 2310, the NTC element 2420, the resistor 2440, the lower body 2510, and the upper body 2520 are prepared.
  • a plurality of bumps 2601 to 2607 which will be connected to the transistor 2310, the NTC element 2420 and the resistor 2440 are formed on the lower body 2510, and metal lines 2701 to 2706 are then formed to connect the bump 2601 to 2607 to one another.
  • the first to third bumps 2601, 2602 and 2603 which will be connected respectively to the collector, base and emitter of the transistor 2310 are formed on the lower body 2510
  • the fourth and fifth bumps 2604 and 2605 which will be connected respectively to terminals of the NTC element 2420 are formed
  • the sixth and seventh bumps 2606 and 2607 which will be connected respectively to terminals of the resistor 2440 are formed.
  • first metal line 2701 for connection between the first and fourth bumps 2601 and 2604
  • second metal line 2702 for connection between the second and fifth bumps 2602 and 2605
  • third metal line 2703 for connection between the second and seventh bumps 2602 and 2607
  • fourth metal line 2704 for connection between the third and sixth bumps 2603 and 2606
  • fifth metal line 2705 extending from the fourth bump 2604 to one end of the lower body 2510 for connection with the first external electrode terminal 2100
  • sixth metal line 2706 extending from the sixth bump 2606 to the other end of the lower body 2510 for connection with the second external electrode terminal 2200.
  • the collector, base and emitter of the transistor 2310 are connected to the first to third bumps 2601, 2602 and 2603, respectively; the NTC element 2420 is connected to the fourth and fifth bumps 2604 and 2605; and the resistor 2440 is connected to the sixth and seventh bumps 2606 and 2607.
  • the first and second external electrode terminals 2100 and 2200 are connected to the fifth and sixth metal lines 2705 and 2706, respectively. Accordingly, the protection circuit shown in Fig. 15 can be manufactured and obtained.
  • the lower body 2510 is then packaged onto the upper body 2520 to thereby complete the battery protection chip 2000 as shown in Fig. 18 (c).
  • a portion of each of the first and second external electrode terminals 2100 and 2200 protrudes to the outside of the body 2500 in the form of a straight line.
  • a process of manufacturing a battery protection chip is not limited to the above description and may be implemented in various ways.
  • Metal pads may be formed on the lower body instead of the bumps, and the transistor, the NTC element and the resistor may be soldered to the metal pads.
  • the protection circuit including the transistor, the NTC element and the resistor may be first formed on an additional PCB, packaged and then connected to the external electrode terminals, to thereby manufacture the battery protection chip.
  • circuit elements including a transistor, an NTC element and a resistor may be formed on a wafer through a semiconductor manufacturing process, and then, a plurality of dies with the elements electrically connected to each other are made, packaged and connected to the external electrode terminals to thereby manufacture a battery protection chip.
  • the individual elements are formed, connected to one another through the wires or metal lines and then packaged to manufacture a battery protection chip.
  • the present invention is not limited thereto. That is, the elements constituting the battery protection chip may be formed on a single wafer, electrically connected to one another in a wafer level and connected to the outside through the bonding pads.
  • the transistor is formed on the wafer, and the resistor and NTC element which will be connected respectively to the base, emitter and collector of the transistor are then formed on the wafer. They are passivated, and the bonding pads serving as external electrode terminals connected to the outside are then formed. Next, the wafer is cut into die chips which in turn are packaged to manufacture a battery protection chip.
  • the package is determined to be successful in the test. That is, the package is mounted in a device whose internal temperature can be adjusted, and current is applied to both terminals of the package. If the current flowing through the package is 5D or less at a temperature of 25 0 C and several hundreds rnA or more at 8O 0 C, the package is determined to be successful in the test. More specifically, the package is determined to be successful in the test, when the current is greater than 100mA at a temperature of 8O 0 C. This is because a current of 5D or less should flow through the battery protection chip of the present invention in a normal operation such that no leakage current can be produced and a current should flow well at a temperature of 8O 0 C or more.
  • Fig. 19 is a conceptual diagram of a battery pack according to a first modification of the seventh embodiment of the present invention.
  • a battery pack 100 according to this modification of the seventh embodiment includes a battery body 10 having positive and negative electrodes 11 and 12, and a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature.
  • the battery pack 100 further includes a PTC element 30 disposed on the negative electrode 12 to block external current according to the temperature.
  • the battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200, a switching unit 2300 for selectively connecting the first and second external electrode terminals 2100 and 2200 of the chip in response to a control voltage, a control voltage generator 2400 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 according to the temperature to generate the control voltage, and a body for packaging the switching unit 2300 and the control voltage generator 2400.
  • the control voltage generator 2400 includes an NTC element 2420 and a first resistor 2440 connected between the first and second external electrode terminals 2100 and 2200.
  • the switching unit 2300 includes a transistor 2310 and a second resistor 2320 connected between the first and second external electrode terminals 2100 and 2200.
  • An internal circuit of the battery protection chip 2000 includes a transistor 2310 of which collector is connected to the first external electrode terminal 2100, an NTC element 2420 connected between the base of the transistor 2310 and the first external electrode terminal 2100, a first resistor 2440 connected between the base of the transistor 2310 and the second external electrode terminal 2200, and a second resistor 2320 connected between the emitter of the transistor 2310 and the second external electrode terminal 2200.
  • the first resistor 2440 may be connected between the base and emitter of the transistor.
  • the battery protection chip 2000 may further include an additional capacitor between the first and second external electrode terminals 2100 and 2200.
  • the battery protection chip 2000 may further include a capacitor connected in parallel with the NTC element 2420.
  • the battery protection chip 2000 may further include a capacitor connected in parallel with the first resistor 2440.
  • the first resistor 2440 has a resistance of 0.5 ⁇ to 2D and the second resistor 2320 has a resistance of 10 to 50 ⁇ .
  • a digital transistor in which the transistor 2310 and the second resistor 2320 are installed in a single chip may be employed.
  • the second resistor 2320 may be physically connected to the second external electrode terminal 2200 which in turn is physically connected to the PTC element 30. Accordingly, when current flows through the switching unit 2300, i.e. when current flows due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, the temperature of the second resistor 2320 physically connected to the PTC element 30 rises and resultant heat is applied to the PTC element 30. Therefore, the battery body can be electrically disconnected from the outside. [140] The operation of the battery pack according to this embodiment having the aforementioned structure and characteristics will be described.
  • the transistor 2310 will be turned off.
  • the predetermined temperature may be an additionally set temperature or a temperature immediately before the battery pack 100 explodes. The temperature can be set by adjusting the characteristic of the NTC element 2420, the driving voltage of the transistor 2310 or the resistance of the first resistor 2440.
  • the predetermined temperature is set to 100 0 C and thus the battery protection chip 2000 starts to operate at this temperature.
  • the resistance of the NTC element 2420 drops to about 7.4D and a voltage of 3.7V is applied across the NTC element 2420.
  • a voltage (operation voltage) of 0.5 V is applied across the first resistor 2440 and the transistor 2310 is then turned on. That is, a path along which the transistor 2310 and the second resistor 2320 are connected in series with each other is established between the positive and negative electrodes 11 and 12.
  • the battery is electrically short-circuited and the battery is thus changed from a high energy state to a low energy state to thereby prevent the battery from being expanded and exploded.
  • the transistor 2310 is turned on, electrical current flows rapidly from the battery but is suppressed by the second resistor 2320.
  • the battery protection chip 200 operates to cause the battery to be forcibly discharged such that the battery is in a low energy state to thereby prevent the battery from being expanded and exploded.
  • the present invention is not limited thereto. That is, a variety of elements with temperature-dependent resistance may be employed.
  • the element with temperature-dependent resistance may be a PTC, a CTR or the like.
  • the element is not limited to the use in the transistor 2310, but a variety of elements for performing switching operation according to the voltage change may be employed. That is, in this embodiment, a transistor 2310 serving as a switching device is controlled to be turned on and off according to the voltage division by a resistance difference between the NTC element 2420 and the first resistor 2440. Therefore, an element of which resistance decreases as the temperature rises is preferably used as the NTC element 2420, while an element of which resistance increases as the temperature rises is preferably used as the first resistor 2440.
  • the battery pack of the present invention may include a chip capable of protecting the battery against the overcharge and overcurrent as well as ensuring the thermal stability.
  • FIG. 20 is a conceptual diagram of a battery pack according to a second modification of the seventh embodiment of the present invention.
  • a battery pack 100 includes a battery body 10 which has positive and negative electrodes 11 and 12 and can be charged and discharged, a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the change in current/voltage from the battery body 10, and a PTC element 30 physically connected to a portion of the battery protection chip 2000 to block external current according to the temperature.
  • the battery protection chip 2000 includes a switching unit 2300 and a control voltage generator 2400.
  • the battery protection chip 2000 includes first and second external terminal electrodes 2100 and 2200 connected respectively to the positive and negative electrodes 11 and 12.
  • the battery protection chip 2000 includes a transistor 2310 of which collector is connected to the first external terminal electrode 2100, a third resistor 2460 connected between a base of the transistor 2310 and the first external terminal electrode 2100, a fourth resistor 2480 connected between the base and emitter of the transistor 2310, and a second resistor 2320 connected between the emitter of the transistor 2310 and the second external terminal electrode 2200.
  • the transistor 2310 Since the transistor 2310 is turned on, a current path is established between the positive and negative terminals 11 and 12 of the battery pack 100 to cause the battery body 10 to be forcibly discharged. In this manner, the battery current is discharged to drop the battery voltage. At this time, if the transistor 2310 of the battery protection chip 2000 is turned on, the second resistor 2320 controls the rapid current flow. Further, since the temperature of the second resistor 2320 rapidly rises, the resistance of the PTC 30 physically connected to the second resistor 2320 rapidly increases to block a current path toward the terminal of the external charger 40 such that the battery cannot be charged any longer.
  • the voltage of the battery pack 100 is 4.3V or less due to the normal charge, it is divided by the second, third and fourth resistors 2320, 2460 and 2480 such that a voltage of 3.799V or less is applied across the third resistor 2460, a voltage of 0.499V or less is applied across the fourth resistor 2480 and a voltage of 0.0003V or less is applied across the second resistor 2320. That is, since a voltage of 0.5V or less is applied across the fourth resistor 2480 connected between the emitter and base of the transistor 2310, the transistor 2310 is turned off.
  • the battery protection chip of this modification may be configured as a single chip into which the chips according to the first and second modifications are combined.
  • a third modification of the seventh embodiment of the present invention will be described with reference to the accompanying drawings. A description of the third modification which overlaps those of the previous embodiments and modifications will be omitted herein.
  • Figs. 21 and 22 are conceptual diagrams of a battery pack according to the third modification of the seventh embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
  • the battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively.
  • the battery protection chip 2000 further includes a first transistor 2310a for dividing a voltage between the first and second external electrode terminals 2100 and 2200 by a first resistor 2440 and an NTC element 2420 of which resistance varies with the temperature and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage; a second transistor 2310b for dividing the voltage between the first and second external electrode terminals 2100 and 2200 by third and fourth resistors 2460 and 2480 and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage; and second resistors 2320a and 2320b connected between the first transistor 2310a and the second external electrode terminal 2200 and between the second transistor 2310b and the second external electrode terminal 2200, respectively.
  • the second resistors 2320a and 2320b may be replaced with a single resistor. That is, as shown in Fig. 22, the battery protection chip 2000 may include a second resistor 2310 connected between the bases of the first and second transistors 2310a and 2310b and the second external electrode terminal 2200.
  • the circuit for ensuring the thermal stability and the circuit for protecting the battery against the overcharge and overcurrent may be incorporated into a single switching device.
  • Such a fourth modification of the seventh embodiment according to the present invention will be described with reference to the accompanying drawings. A description of the fourth modification which overlaps those of the previous embodiments and modifications will be omitted herein.
  • FIGs. 23 and 24 are conceptual diagrams of a battery pack according to the fourth modification of the seventh embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
  • the battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively. Further, the battery protection chip 2000 includes a transistor 2310 for establishing a current path between the first and second external electrode terminals 2100 and 2000 according to a parallel resistance value of a third resistor 2460 and an NTC element 2420 of which resistance varies with the temperature and a parallel resistance value of first resistor and fourth resistors 2440 and 2480.
  • the first and fourth resistors 2440 and 2480 may be replaced with a single resistor. That is, the battery protection chip 2000 may include a fifth resistor 2490 with the parallel resistance value of the first and fourth resistors 2440 and 2480.
  • a PTC element may be arranged on the positive terminal.
  • Fig. 25 is a conceptual diagram of a battery pack according to the fifth modification of the seventh embodiment of the present invention.
  • a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
  • the battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively. Further, the battery protection chip 2000 includes a transistor 2310 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 by a first resistor 2440 and an NTC element 2420 of which resistance varies with the temperature and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage, and a second resistor 2320 connected between a collector of the transistor 2310 and the first external electrode terminal 2100.
  • the battery pack 100 includes a PTC element 30 physically connected to the first external electrode terminal 2100 to control the current flowing through the positive terminal 11. In this manner, when the overheating/overcharge/overcurrent is produced in the battery, the battery can be electrically disconnected from an external circuit connected thereto by arranging the PTC element 30 on the positive terminal 11.
  • a swelling test and a hot box test were performed on a battery pack including the battery protection chip according to the first modification of the seventh embodiment.
  • a lithium- ion battery with an operating voltage of 4.2V and a current capacity of 100OmAh was used as the battery body.
  • a 1.24W-2.5V P-channel MOFET with a threshold voltage of 0.45V was used as the transistor.
  • the first resistor has a resistance of 2OD
  • the second resistor has a resistance of 10 ⁇
  • the NTC element has a resistance of 875D at 25 0 C and a resistance of 76.2D at 85 0 C.
  • Table 1 shows test results obtained from the swelling test and the hot box test conducted on the battery pack including the battery protection chip.
  • the battery pack temperature is increased from the room temperature to 85 0 C at a rate of about 5°C/min and kept for about four hours, and then decreased to the room temperature at a rate of about 5°C/min. Throughout seven tests, it has been measured that the rates of change before and after the tests are conducted are all 3% or less, as shown in Table 1.
  • the temperature is increased from the room temperature to 15O 0 C at a rate of about 5°C/min and kept for about 10 minutes, and then decreased to the room temperature at a rate of about 5°C/min. At this time, it is determined whether the battery pack has been burnt. It can be seen that the battery packs according to the present invention were not burnt at all.
  • the current is 4.5 to 5D at the room temperature (about 25 0 C), i.e. the current does not substantially flow, whereas the current is increased to 113 to 150mA at about 85 0 C.

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Abstract

The present invention relates to a battery protection chip, a method of manufacturing the battery protection chip and a battery pack including the battery protection chip. The battery protection chip of the present invention comprises first and second external electrode terminals, a switching unit for selectively connecting the first and second external electrode terminals according to a control voltage, a control voltage generator for dividing a voltage between the first and second external electrode terminals according to a temperature to generate the control voltage, and a body for packaging the switching unit and the control voltage generator. The method of manufacturing the battery protection chip so configured and the battery pack including the same are also provided. According to the present invention, the production costs can be significantly reduced by simplifying a battery protection chip including a temperature sensor and a switching device operating with a predetermined voltage change into a single chip; the overcharge can be prevented, the overcurrent can be controlled and the thermal stability can also be ensured; of the mass production can be made and the malfunction and failure can also be prevented by adjusting characteristic variations between a plurality of the battery protection chips within a certain range.

Description

Description
CIRCUIT AND CHIP FOR PROTECTING BATTERY, METHOD OF MANUFACTURING THE SAME AND BATTERY PACK
HAVING THE SAME
Technical Field
[1] The present invention relates to a protection circuit and a battery pack having the same, and more particularly, to a battery pack having a protection device capable of protecting a battery against overcharge and overcurrent and ensuring thermal stability under all the conditions of use of the battery. Background Art
[2] In general, a battery comprises positive and negative electrode plates and electrolyte and refers to a device for generating direct current electromotive force through a chemical reaction to use the generated force as electrical power. In the battery, chemical energy of a chemical material contained therein is converted to electrical energy through an electrochemical oxidation-reduction reaction.
[3] The battery may be classified into a primary battery that cannot be recharged after use and a secondary battery that can be recharged and reused when its voltage drops below to a predetermined voltage range.
[4] The aforementioned battery will be operated, as follows. The negative electrode of the battery is made of a material that is oxidized by losing electrons, whereas the positive electrode is made of a material that is reduced by accepting electrons. When the battery connected to an external device (e.g., a lamp or an electronic appliance) works, i.e. the discharging reaction of the battery is performed, two electrodes are changed into electrochemically different states, respectively. At this time, electrical circuitry is formed in the electrolyte by means of the mass transfer of anions and cations toward the negative and positive electrodes.
[5] A primary battery cannot be recharged because a reverse reaction is not produced, whereas a secondary battery can be charged and returned to an original chemical state.
[6] Accordingly, a secondary battery can be reused and easily manufactured to have a small size and weight. However, if the secondary battery is overcharged, oxygen gas may be generated at the positive electrode, a lithium metal may be deposited on the negative electrode, and the electrolyte may be decomposed into gas. These continued reactions may lead to explosion or fire. Particularly, the temperature in a lithium battery (lithium-ion battery or lithium-polymer battery), which is used as a secondary battery, rapidly rises due to the external mechanical impact, the change in thermal environment, the electrical connection and the like caused by instable materials of the battery, so that the expansion, explosion and the like of the battery are produced.
[7] To prevent the aforementioned problems, a protection circuit such as a protection circuit module (PCM) is employed in most of the secondary batteries.
[8] The PCM is used to perform the functions of protecting the battery against the overcurrent, the overcharge, overdischarge, and short circuit when the battery is charged. To this end, the PCM is composed of active elements such as an integrated circuit (IC) or field effect transistor (FET), and passive elements such as a resistor and capacitor.
[9] Such a PCM is disclosed in Korean Patent Nos. 10-301346 and 10-422758 and
Korean Patent Laid-Open Publication No. 10-2004-13354. In Korean Patent No. 10-301346, a PCM with an integrated circuit is used to protect a secondary battery, but the integrated circuit is expensive and complex. Further, in Korean Patent Laid-Open Publication No.10-2004-13354, a PCM with a plurality of sensors and a discharging unit is used to protect a secondary battery. That is, a control unit controls a protection c ircuit and a charging/discharging unit based on a value inputted from a voltage or temperature sensor. In this case, the production costs are increased due to the use of the voltage or temperature sensor, and the circuit becomes complicated since the discharging unit should discharge the overcurrent based on the value inputted from the sensor. In a case where this battery is to be actually implemented, the total production costs of the battery are increased.
[10] In Korean Patent No. 10-422758, a temperature sensing device in which an overcurrent blocking element or a PTC (positive temperature coefficient) element is connected in series with an NTC (negative temperature coefficient) element prevents the overcurrent from flowing into the NTC element such that the NTC element cannot be damaged. The temperature sensing device of the patent is only to protect the NTC element when a temperature sensing terminal with the NTC element connected thereto is connected with a hot-side terminal. However, the temperature sensing device cannot be directly used to control the secondary battery. Additional FET and adjuster IC are essentially used to detect the change of the NTC element and to protect the secondary battery. However, if the temperature sensed by the external NTC element is adjusted using the adjuster IC and the FET, the circuit is complicated and the production costs of the secondary battery are increased as described above.
[11] In addition, elements constructing a conventional PCM consume considerable current, which may lower an open circuit voltage (OCV) together with leakage current of a battery. Further, the life span of the battery is shortened due to the power consumption of the PCM itself. Even though the PCM serves to control the overcharge, overcurrent and the like in order to ensure the stability of battery when the battery is charged, it is difficult to ensure the stability of battery in a typical condition of use except a charging condition.
[12] Further, since the PCM is a circuit formed with active and passive elements as previously described, the characteristic variations between individual elements has an effect on overall circuit characteristics. For example, packaged transistors have different operation voltages. Even though the packaged transistors are manufactured from the same wafer, they have a minor difference in their operation voltages. Furthermore, the NTC elements exhibit different changes in temperature-dependent resistance. Therefore, if such a plurality of PCM circuits are manufactured using these circuit elements and mounted for the purpose of battery protection, the variation between the individual circuit elements leads to characteristic variations between the PCM circuits. Accordingly, since some of the PCM circuits do not operate under a desired condition, the life span of the battery may be shortened and the performance thereof can also be deteriorated. In addition, the expansion or explosion of the battery cannot be prevented. Disclosure of Invention Technical Problem
[13] The present invention is conceived to solve the aforementioned problems. Accordingly, an object of the present invention is to provide a battery protection circuit and chip capable of simplifying a control module including a temperature sensor and a switching device operating with a predetermined voltage change into a single chip to thereby significantly reduce its production costs, of preventing the overcharge, controlling the overcurrent and ensuring the thermal stability, of adjusting characteristic variations between a plurality of control modules within a certain range for their mass production, and of preventing the malfunction and failure of the control module; a method of manufacturing the same; and a battery pack having the same. Technical Solution
[14] According to an aspect of the present invention for achieving the object, there is provided a battery protection chip, comprising first and second external electrode terminals; a switching unit for selectively connecting the first and second external electrode terminals according to a control voltage; a control voltage generator for dividing a voltage between the first and second external electrode terminals according to a temperature to generate the control voltage; and a body for packaging the switching unit and the control voltage generator.
[15] Preferably, the switching unit includes a transistor which has a collector and an emitter connected to the first and second external electrode terminals, respectively, and operates according to the control voltage. The battery protection chip may further comprise a resistor connected between the first external electrode terminal and the collector of the transistor or between the second external electrode terminal and the emitter of the transistor, wherein the resistor is connected to the first or second external electrode terminal.
[16] Preferably, the control voltage generator comprises a first voltage dividing means connected between the first external electrode terminal and a control voltage node; and a second voltage dividing means connected between the second external electrode terminal and the control voltage node. More preferably, each of the first and second voltage dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a voltage dividing resistor element, a varistor, and a Zener diode, each having a temperature-dependent resistance characteristic.
[17] According to another aspect of the present invention, there is provide a method of manufacturing a battery protection chip, comprising the steps of (a) providing a switching device, a voltage dividing element, and first and second external electrode terminals; (b) electrically connecting and packaging the switching device, the voltage dividing element and the first and second external electrode terminals with one another such that a voltage between the first and second external electrode terminals is divided according to a temperature and the first and second external electrode terminals is selectively connected with each other according to the divided voltage; and (c) testing the packaged and electrically connected circuit elements to detect failure.
[18] Preferably, the switching device is a transistor and the voltage dividing element is at least one selected from the group consisting of an NTC element, a PTC element and a voltage dividing resistor element, each having a temperature-dependent resistance characteristic.
[19] Preferably, the step (b) comprises the steps of connecting the voltage dividing element and the switching device between the first and second external electrode terminals through wires and connecting one end of the voltage dividing element and the switching device through a wire; and packaging the voltage dividing element and the switching device.
[20] Preferably, the step (b) comprises the steps of preparing upper and lower bodies; arranging the switching device and the voltage dividing element within the lower body and disposing first and second external electrode terminals onto both ends of the lower body, respectively; connecting the switching device, the voltage dividing element and the first and second external electrode terminals through wires; and sealingly coupling the upper body onto the lower body with the wire-connected switching device and voltage dividing element arranged thereon.
[21] Preferably, the step (b) comprises the steps of preparing upper and lower bodies; forming pads to be connected with the switching device and the voltage dividing element on the lower body and then electrically connecting the pads; connecting the switching device and the voltage dividing element to the pads to be electrically connected to the first and second external electrode terminals; and coupling the upper body onto the lower body to package the switching device and the voltage dividing element.
[22] According to a further aspect of the present invention, there is provided a battery pack, comprising a battery body having positive and negative electrodes; and a battery protection chip operating to selectively connect the positive and negative electrodes according to a temperature.
[23] According to a still further aspect of the present invention, there is provided a battery pack, comprising a battery body having positive and negative electrodes; a voltage dividing means for dividing a voltage from the battery body; and a control module including a switching means operating to establish a current path between the positive and negative electrodes according to the voltage divided by the voltage dividing means.
[24] Preferably, the voltage dividing means comprises at least two dividing means between the positive and negative electrodes connected in series with each other, and the dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a varistor, a Zener diode, a dividing resistor element.
[25] Preferably, the switching means includes a transistor which has a collector connected to the positive electrode and an emitter connected to the negative electrode and operates with the voltage dividing means. The battery pack of the present invention may further comprises a current control resistor connected between the emitter of the transistor and the negative electrode or between a collector of the transistor and the positive electrode; and a temperature control switch brought into physical contact with the current control resistor to control a current path through the negative or positive electrode.
[26] According to a still further aspect of the present invention, there is provided a battery pack, comprising: a battery body having positive and negative electrodes; and a PTC element and a heating element connected in parallel with each other on the positive electrode.
[27]
Advantageous Effects
[28] According to the present invention as described above, it is possible to prevent the overcharge, control the overcurrent and to ensure the thermal stability through a control module capable of detecting a change in temperature, voltage and current of a battery pack and causing the battery to be discharged according to the detected result.
[29] Further, since the control module is composed of a voltage dividing means and a switching means, the circuit thereof can be simplified. [30] Furthermore, the production costs can be significantly reduced by simplifying a control module including a temperature sensor and a switching device operating with a predetermined voltage change into a single chip. [31] In addition, since characteristic variations between a plurality of battery protection chips can be adjusted within a certain range, it is possible to mass produce the chips and to prevent the malfunction and failure of the chips.
Brief Description of the Drawings [32] Fig. 1 is a conceptual diagram of a battery pack according to a first embodiment of the present invention. [33] Fig. 2 is a graph illustrating a temperature-resistance characteristic of an NTC element. [34] Fig. 3 is a graph illustrating a temperature-resistance characteristic of a PTC element. [35] Figs. 4 to 6 are conceptual diagrams illustrating the arrangement of a control module according to a first embodiment of the present invention. [36] Fig. 7 is a conceptual diagram of a battery pack according to a second embodiment of the present invention. [37] Figs. 8 and 9 are conceptual diagrams illustrating a battery pack according to a third embodiment of the present invention. [38] Figs. 10 and 11 are conceptual diagrams illustrating a battery pack according to a fourth embodiment of the present invention. [39] Fig. 12 is a conceptual diagram illustrating a battery pack according to a fifth embodiment of the present invention. [40] Fig. 13 is a conceptual diagram illustrating a battery pack according to a sixth embodiment of the present invention. [41] Fig. 14 is a conceptual diagram illustrating a battery pack according to a seventh embodiment of the present invention. [42] Fig. 15 is a conceptual diagram of a battery protection chip according to the seventh embodiment of the present invention. [43] Figs. 16 to 18 are views illustrating processes of manufacturing the battery protection chip according to the seventh embodiment of the present invention. [44] Fig. 19 is a conceptual diagram of a battery pack according to a first modification of the seventh embodiment of the present invention.
[45] Fig. 20 is a conceptual diagram of a battery pack according to a second modification of the seventh embodiment of the present invention. [46] Figs. 21 and 22 are conceptual diagrams of a battery pack according to a third mod- ification of the seventh embodiment of the present invention.
[47] Figs. 23 and 24 are conceptual diagrams of a battery pack according to a fourth modification of the seventh embodiment of the present invention.
[48] Fig. 25 is a conceptual diagram of a battery pack according to a fifth modification of the seventh embodiment of the present invention. Best Mode for Carrying Out the Invention
[49] Hereinafter, preferred embodiments of the present invention will be described in more detail with reference to the accompanying drawings. However, the present invention is not limited to the preferred embodiments thereof set forth herein but can be implemented in different forms. Rather, the preferred embodiments are merely provided to allow the present invention to be completely described herein and to fully convey the scope of the invention to those skilled in the art. In the drawings, like elements are designated by like reference numerals.
[50] Fig. 1 is a conceptual diagram of a battery pack according to a first embodiment of the present invention.
[51] Referring to Fig. 1, a battery pack 100 according to this embodiment includes a battery body 10 having positive and negative electrodes 11 and 12, and a control module 20 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature. The battery pack 100 may further include a PTC element 30 connected to the negative electrode 12 to block external current according to the temperature.
[52] The battery may be any battery including a secondary battery or a fuel cell. The secondary battery may be a lead-acid battery, an alkaline battery, a gas battery, a lithium-ion battery, a nickel-hydrogen battery, a nickel-cadmium battery, a polymer battery or the like. A small-sized secondary battery has been shifted from a nickel- cadmium battery to a nickel-hydrogen battery and a lithium-ion battery. A lithium polymer battery has been used which is obtained by replacing an electrolyte with a polymer in the lithium-ion battery. Further, the fuel cell may be a molten carbonate fuel cell using an alkaline solution as an electrolyte, a solid electrolyte fuel cell, a phosphoric acid electrolyte fuel cell or the like. In this case, the electrolyte may be pure hydrogen and oxygen. The electrolyte may be gas fuel using fossil fuel such as methane and natural gas other than hydrogen or may be liquid fuel such as methanol and hydrazine.
[53] The control module 20 includes a transistor 22 with a collector connected to the positive electrode, an NTC element 21 connected between a base of the transistor 22 and the positive electrode 11, a first resistor 23 connected between the base of the transistor 22 and the negative electrode 12, and a second resistor 24 connected between an emitter of the transistor 22 and the negative electrode 12. Although it has been illustrated in Fig. 1 that the first resistor 23 is connected between the transistor base and the negative electrode 12, the present invention is not limited thereto. The first resistor 23 may be connected between the base and emitter of the transistor. An additional capacitor may be provided between the positive and negative electrodes 11 and 12. The battery pack 100 may further include a capacitor connected in parallel with the NTC element 21. The battery pack 100 may further include a capacitor connected in parallel with the first resistor 23.
[54] Preferably, an NPN transistor is used as the transistor 22. Preferably, a turn-on voltage of the transistor is within a range of 0.3 to 0.7V, the first resistor 23 has a resistance of 0.5 to 2D and the second resistor 24 has a resistance of 10 to 50Ω. In this case, a PNP transistor may be used as the transistor 22. Further, a digital transistor with the transistor 22 and the first resistor 23 integrated into a single chip may be employed. Preferably, the transistor 22 may be a BJT or MOS transistor. Characteristics of the individual elements constituting the control module 20 of the present invention are not limited to the aforementioned values but may be variously changed according to voltage and current generated in the battery body. That is, an NTC or PTC element may be used as the first resistor 23, whereas a resistor may be substituted for the NTC element 21.
[55] Hereinafter, characteristics of the NTC and PTC elements according to the present invention will be described.
[56] Fig. 2 is a graph illustrating a temperature-resistance characteristic of an NTC element, and Fig. 3 is a graph illustrating a temperature-resistance characteristic of a PTC element.
[57] Referring to Fig. 2, the resistance of the NTC element 21 decreases nonlinearly as the temperature rises. For example, the resistance of the NTC element 21 is about IOOD at room temperature but decreases rapidly to about 7.4D at a temperature of 1000C. In this embodiment, the NTC element 21 preferably has a resistance of 90 to 150D at a temperature of 18 to 3O0C and a resistance of 4 to 1OD at a temperature of 90 to 12O0C. Of course, the characteristic of the NTC element of the present invention is not limited thereto, but the characteristic values of the NTC element may be changed according to characteristics of the first resistor and the transistor.
[58] Referring to Fig. 3, the PTC element 30 is an element of which resistance is maintained constant at a given temperature but rapidly increases when a temperature exceeds a certain value. That is, the PTC element 30 has a resistance of a few to several tens ohms at room temperature. However, when a temperature exceeds a given temperature, the PTC element 30 has a resistance of several hundreds ohms enough to substantially operate as a nonconductor. [59] In this embodiment, the PTC element 30 is disposed on the negative electrode 12 to control the negative electrode to be short-circuited according to the temperature. That is, a first negative electrode extending from the battery body is connected to one terminal of the PTC element 30, and a second negative electrode exposed to the outside of the battery pack is connected to the other terminal of the PTC element 30. In this embodiment, the PTC element 30 is preferably brought into physical contact with the second resistor 24. Accordingly, if the battery temperature is increased when the battery is charged, the second resistor 24 is heated and the PTC element 30 brought into physical contact with the second resistor 24 is also heated, so that the external current can be blocked. At this time, the second resistor 24 is preferably manufactured to have a maximum physical contact area with the PTC element 30. That is, the second resistor 24 is preferably formed into a plate shape to come into contact with top, side and bottom surfaces of the PTC element 30.
[60] The operation of the battery pack having the aforementioned configuration and characteristics according to this embodiment will be described.
[61] In a normal operation, when a constant DC voltage is applied from the battery to the outside or when the positive and negative electrodes 11 and 12 are in a floating state, an internal temperature of the battery does not rise and the resistance of the NTC element 21 is much greater than those of the first and second resistors 23 and 24. Accordingly, even though the voltage from the battery body is divided by the NTC element 21, the first resistor 23 and the second resistor 24, most of the voltage is applied across the NTC element 21. Since a voltage across the first resistor 23 does not reach the turn-on voltage of the transistor 22, the transistor 22 is turned off. Accordingly, a current path is not established between the positive and negative electrodes 11 and 12. For example, if the voltage of the battery body is 4.2V, the internal temperature of the battery is 250C, the resistance of the NTC element 21 is 10OD, the resistance of the first resistor 23 is ID and the resistance of the second resistor 24 is 30Ω a voltage of about 4.16V is applied across the NTC element 21 and a voltage of 0.04V is applied between the base and emitter of the transistor 22, i.e. across the first resistor 23. Since a sufficient driving voltage is not applied between the base and emitter of the transistor 22, the transistor 22 will be turned off.
[62] On the other hand, in a case where the internal temperature of the battery rapidly rises due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, the resistance of the NTC element 21 decreases due to the temperature increase. Accordingly, the voltage across the NTC element 21 decreases and the voltage across the first resistor 23 increases.
[63] If the internal temperature of the battery rises to a given temperature and thus a voltage across the first resistor 23 increases to the driving voltage of the transistor 22, the transistor 22 is turned on and a current path is established from the collector to emitter of the transistor. Accordingly, a current path is established between the positive and negative electrodes 11 and 12 of the battery such that the battery can be automatically discharged to prevent the battery from being overheated and thus exploded due to this overheating. The predetermined temperature may be an additionally set temperature or a temperature immediately before the battery pack 100 explodes. The temperature can be set by adjusting the characteristic of the NTC element 21, the driving voltage of the transistor 22 or the resistance of the first resistor 23.
[64] Assume that the predetermined temperature is set to 1000C and that the control module 20 starts to operate at this temperature. When the internal temperature of the battery gradually rises from 250C to 1000C, the resistance of the NTC element 21 drops to about 7.4D and a voltage of 3.7V is applied across the NTC element 21. On the other hand, a voltage (operation voltage) of 0.5V is applied across the first resistor 23 and the transistor 22 is then turned on. That is, a path along which the transistor 22 and the second resistor 24 are connected in series with each other is established between the positive and negative electrodes 11 and 12. Accordingly, the battery is electrically short-circuited and the battery is changed from a high energy state to a low energy state to thereby prevent the battery from being expanded and exploded. At this time, if the transistor 22 is turned on, electrical current flows rapidly from the battery but is suppressed by the second resistor 24.
[65] Further, in a case where the temperature of the battery rises due to the overcharge while the battery pack 100 is charged from an external charger 200, the current flowing through the second resistor 24 increases the temperature of the second resistor 24. Accordingly, the resistance of the PTC element 30 increases rapidly, and a terminal of the charger 200 and the battery pack 100 (negative electrode) are short-circuited to thereby block the external current and prevent the overcharge.
[66] If the battery is stabilized and the battery temperature drops due to the discharge, the resistance of the NTC element 21 increases and thus the voltage across the first resistor 23 decreases to allow the transistor 22 to be turned off. Then, the battery pack 100 can be recharged and reused.
[67] In this manner, when the battery is in a high energy state due to external factors, the control module 20 operates to cause the battery to be forcibly discharged such that the battery is in a low energy state to thereby prevent the battery from being expanded and exploded.
[68] While the NTC element has been used in this embodiment, the present invention is not limited thereto. That is, a variety of elements with temperature-dependent resistance may be used. The element with temperature-dependent resistance may be a PTC, a CTR or the like. Further, the element is not limited to the transistor, but a variety of elements for performing switching operation according to the voltage change may be used. That is, in this embodiment, a transistor serving as a switching device is controlled to be turned on and off according to the voltage division by a resistance difference between the NTC element and the first resistor. Therefore, an element of which resistance decreases as the temperature rises is preferably used as the NTC element, while an element of which resistance increases as the temperature rises is preferably used as the first resistor.
[69] Figs. 4 to 6 are conceptual diagrams illustrating the arrangement of the control module according to the first embodiment of the present invention.
[70] The control module 20 of the present invention is preferably arranged between the internal positive/negative electrodes of the battery body 10 and the positive/negative electrodes 11 and 12 of the battery pack 100. As shown in Fig. 4, the control module 20 may be disposed in a given area of a PCM panel 40 which includes an active element such as a microprocessor or FET and some passive elements to perform the functions of protecting the battery against the overcurrent, overcharge, overdischarge, and short circuit when the battery body 10 is charged. That is, the NTC 21, the transistor 22 and the resistors 23 and 24 are disposed in an empty space of a printed circuit board for the PCM 40 and then electrically connected to one another such that the battery protection function of the PCM 40 can be provided and the explosion of the battery pack due to heating can also be prevented. As shown in Fig. 5, an individual control module panel 20 is formed to include the aforementioned control circuit therein and then arranged between the positive and negative electrodes 11 and 12. At this time, the battery pack 100 may further include the PCM panel 40. Alternatively, only the individual control module panel 20 may be provided in the battery pack 100. In this manner, the aforementioned elements are arranged on the separate printed circuit board and electrically connected to one another, and the printed circuit board is then electrically connected between the positive and negative electrodes 11 and 12. Consequently, the control circuit can be simply configured and the thermal stability of the battery pack can also be ensured without the PCM 40. Further, as shown in Fig. 6, the control module 20 can be brought into contact with a portion of the battery body to immediately sense the temperature change of the battery body 10. That is, the control module 20 is mounted on the printed circuit board or they are connected with each other using a separate wire as described above, and the NTC element 21 is then brought into physical contact with the battery body 10. Accordingly, since the control module 20 can be operated sensitively according to the temperature change of the battery body 10, a more stable battery pack 100 can be obtained. Further, the control module into which the aforementioned structures of Figs. 4 to 6 are combined may be arranged in the battery pack 100 of the present invention. [71] Further, the battery pack of the present invention may include a control circuit capable of protecting the battery against the overcharge and overcurrent and ensuring the thermal stability. A second embodiment of the present invention will be described with reference to the accompanying drawing. A description of the second embodiment which overlaps that of the first embodiment will be omitted herein. The second embodiment may be applied to the first embodiment.
[72] Fig. 7 is a conceptual diagram of a battery pack according to the second embodiment of the present invention.
[73] Referring to Fig. 7, the battery pack 100 includes a battery body 10 which has positive and negative electrodes 11 and 12 and can be charged and discharged, a control module 120 for connecting the positive and negative electrodes 11 and 12 according to a change in current and/or voltage from the battery body 10, and a PTC element 130 which is physically connected to a portion of the control module 120 to block an external current according to the temperature.
[74] The aforementioned control module 120 includes a transistor 122 with a collector connected to the positive electrode 11, a first resistor 121 connected between a base of the transistor 122 and the positive electrode 11, a second resistor 123 connected between the base and emitter of the transistor 122, and a third resistor 124 connected between the emitter of the transistor 122 and the negative electrode 12.
[75] The third resistor 124 and the PTC element 130 are brought into physical contact with each other.
[76] Preferably, an NPN transistor is used as the transistor 122. Preferably, a turn-on voltage of the transistor is within a range of 0.3 to 0.7V, the first resistor 121 has a resistance of 250 to 350D the second resistor 123 has a resistance of 10 to 9OD and the third resistor 124 has a resistance of 10 to 50Ω. Characteristics of the individual elements constituting the control module 120 of this embodiment are not limited to the aforementioned values but may be variously changed according to voltage and current of the battery body 10 when the battery body 10 is charged. The first resistor of this embodiment may be an element such as a varistor (chip varistor) or a Zener diode of which resistance is rapidly changed according to the voltage applied thereto instead of an element with the constant resistance.
[77] Hereinafter, the operation of the aforementioned battery pack will be described.
[78] When a voltage of the battery pack 100 is in a normal state by means of the general charge, the voltage is divided by the first and second resistors 121 and 123 and a voltage insufficient to drive the transistor 122 is then applied between the base and emitter of the transistor 122 to cause the transistor 122 to be turned off. Accordingly, no current path is established between the positive and negative electrodes 11 and 12 of the battery pack 100. However, when the voltage of the battery pack 100 is beyond the normal state by means of the overcharge, the voltage is divided by the first and second resistors 121 and 123 and a voltage sufficient to drive the transistor 122 is applied between the base and emitter of the transistor 122 to cause the transistor 122 to be turned on. Since the transistor 122 is turned on, a current path is established between the positive and negative electrodes 11 and 12 of the battery pack 100 to cause the battery body 10 to be forcibly discharged. In this manner, the battery current is discharged to drop the battery voltage. At this time, if the transistor 122 is turned on, the third resistor 124 controls the rapid current flow. Further, since the temperature of the third resistor 124 rapidly rises, the resistance of the PTC element 130 physically contact to the third resistor 124 also increases rapidly to block the current path toward the terminal of the external charger 200 such that the battery cannot be charged any longer.
[79] Assume that when a maximum target voltage of the battery pack is 4.3V and an operation voltage of the transistor 122 is 0.5V, the resistance of the first resistor 121 is 304D, the resistance of the second resistor 123 is 4OD and the resistance of the third resistor 124 is 30Ω.
[80] When the voltage of the battery pack 100 is 4.3V or less due to the normal charge, it is divided by the first, second and third resistors 121, 123 and 124 such that a voltage of 3.799V or less is applied across the first resistor 121, a voltage of 0.499V or less is applied across the second resistor 123, and a voltage of 0.0003V or less is applied across the third resistor 124. That is, since a voltage of 0.5V or less is applied across the second resistor 123 connected between the emitter and base of the transistor 122, the transistor 122 is turned off. On the other hand, when the voltage of the battery pack 100 is greater than 4.3V due to the overcharge, a voltage of 3.799V or more is applied across the first resistor 121 and a voltage of 0.499V or more is applied across the second resistor 123. That is, since a voltage of 0.5V or more is applied across the second resistor 123 connected between the emitter and base of the transistor 122, the transistor 122 is turned on. Accordingly, a current path is established between the positive and negative electrodes of the battery pack 100 such that the current in the battery can be discharged to lower the battery voltage.
[81] As described above, since it is possible to protect the battery against the overcharge and overcurrent through the control module 120 of this embodiment, a conventional battery protection system can be replaced with the system of the present invention. Further, since a circuit structure is simplified, an inexpensive battery protection system can be provided.
[82] In addition, the control module of the present invention may be configured as a single module into which the control modules according to the first and second embodiments are combined. A third embodiment of the present invention will be described with reference to the accompanying drawings. A description of the third embodiment which overlaps those of the first and second embodiments will be omitted herein. The third embodiment may be applied to the first and second embodiments.
[83] Figs. 8 and 9 are conceptual diagrams illustrating a battery pack according to the third embodiment of the present invention.
[84] Referring to Figs. 8 and 9, a battery pack 100 of this embodiment includes a first transistor 222 for dividing a voltage of the battery pack 100 by a first resistor 223 and an NTC element 221 of which resistance varies with the temperature of the battery body 10 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, a second transistor 226 for dividing the voltage of the battery pack 100 by third and fourth resistors 225 and 227 and then establishing a current path between the positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, second and fifth resistors 224 and 228 connected respectively between the first transistor 222 and the negative electrode 12 and between the second transistor 226 and the negative electrode 12, and a PTC element 210 physically connected to the second and fifth resistors 224 and 228 to control current flowing through the negative electrode 12.
[85] At this time, the second and fifth resistors 224 and 228 may be replaced with a single resistor. That is, as shown in Fig. 9, a sixth resistor 229 may be connected between the bases of the first and second transistors 222 and 226 and the negative electrode 12.
[86] In this manner, the module capable of protecting the battery against the overcharge and overcurrent in the battery pack and the module capable of ensuring the thermal stability of battery can be manufactured into a single package or separate package. Thus, the battery stability can be enhanced and the production costs of the battery pack can also be reduced as compared to a conventional PCM module.
[87] In addition, the circuit for ensuring the thermal stability and the circuit for protecting the battery against the overcharge and overcurrent may be incorporated into a single switching device. A fourth embodiment of the present invention will be described with reference to the accompanying drawings. A description of the fourth embodiment which overlaps those of the first to third embodiments will be omitted herein. The fourth embodiment may be applied to the first to third embodiments.
[88] Figs. 10 and 11 are conceptual diagrams illustrating a battery pack according to the fourth embodiment of the present invention.
[89] Referring to Figs. 10 and 11, a battery pack 100 of this embodiment includes a transistor 325 for dividing a voltage of the battery pack 100 according to a parallel resistance value of a first resistor 322 and an NTC element 321 of which resistance varies with the temperature of the battery body 10 and a parallel resistance value of a second resistor 323 and a third resistor 324 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage.
[90] Although it has not been illustrated, the battery pack of this embodiment may further include a resistor which is connected between a base of the transistor 325 and the negative terminal 12 and a PTC element which is physically connected to the resistor to control the current flowing through the negative terminal.
[91] The second and third resistors 323 and 324 may be replaced with a single resistor.
That is, a single resistor having a parallel resistance value of the second and third resistors 323 and 324 may be employed.
[92] In a normal operation of the control module 320, the transistor 325 operates through the voltage division between the positive and negative electrodes 11 and 12 according to the parallel resistance value of the NTC element 321 and the first resistor 322 and the parallel resistance value of the second and third resistors 323 and 324. That is, as previously described in the second embodiment, since a voltage sufficient to turn on the transistor 325 is not applied across the second and third resistors 323 and 324 in a normal voltage state, the battery body 10 can be freely charged and discharged. However, if the voltage/current of the battery body 10 increases due to the overcharge, a voltage sufficient to turn on the transistor 325 is applied across the second and third resistors 323 and 324, the transistor 325 is turned on such that a current path is forcibly established between the positive and negative electrodes 11 and 12 to thereby prevent the overcharge and overcurrent. Meanwhile, if the temperature of the battery pack 100 rises due to external factors, the resistance of the NTC element 321 rapidly decreases such that the parallel resistance value of the NTC element 321 and the first resistor 322 decreases. Accordingly, a voltage sufficient to turn on the transistor 325 is applied across the second and third resistors 323 and 324 such that the current path can be forcibly established between the positive and negative electrodes 11 and 12 of the battery to thereby prevent the explosion of the battery.
[93] As described above, it is possible to prevent the battery from being overheated and to lower the production costs of the battery pack due to the simplified structure of the control module capable of preventing the overcharge and overcurrent. Therefore, the battery pack of the present invention can be put to practical use.
[94] In addition, the PTC element may be arranged on the positive terminal. That is, the
PTC element may be arranged not only on the negative terminal of the battery body but also on the positive terminal to control the current flowing through the positive terminal. Such a fifth embodiment of the present invention will be described with reference to the accompanying drawing. A description of the fifth embodiment which overlaps those of the first to fourth embodiments will be omitted herein. The fifth embodiment may be applied to the first to fourth embodiments.
[95] Fig. 12 is a conceptual diagram illustrating a battery pack according to the fifth embodiment of the present invention.
[96] Referring to Fig. 12, a battery pack 100 of this embodiment includes a transistor
422 for dividing a voltage of the battery pack 100 by a first resistor 423 and an NTC element 421 of which resistance varies with the temperature of the battery body 10 and then establishing a current path between positive and negative electrodes 11 and 12 of the battery body 10 according to the divided voltage, a second resistor 424 connected between a collector of the transistor 422 and the positive electrode 11, and a PTC element 410 physically connected to the second resistor 424 to control the current flowing through the positive electrode 11.
[97] The operation of the battery pack according to the present invention so configured will be briefly described. In a normal operation, the resistance of the PTC element 410 is very low and the resistance of the NTC element 421 is very high. Thus, the control module 420 of this embodiment does not operate. However, when the battery temperature rises due to external factors, the resistance of the NTC element 421 nonlinearly decreases and thus a voltage across the first resistor 423 increases. Therefore, the transistor 422 is turned on and thus a current path between the positive and negative electrodes 11 and 12 is established. At this time, current rapidly flows into the second resistor 424 connected between the collector of the transistor 422 and the positive electrode 11 and thus the second resistor 424 is heated. Accordingly, the resistance of the PTC element 410 connected to the second resistor 424 also increases rapidly such that the current flowing into the positive electrode 11 can be blocked to electrically disconnect an external circuit and the battery from each other.
[98] In this manner, the PTC element 410 is arranged on the positive electrode 11 to allow the battery to be electrically disconnected from the external circuit when the overheating/overcharge/overcurrent are produced in the battery.
[99] Of course, the battery can be electrically disconnected from the external circuit only by the PTC element and the heating element. Such a sixth embodiment of the present invention will be described with reference to the accompanying drawing. A description of the sixth embodiment which overlaps those of the aforementioned first to fifth embodiments will be omitted herein. The sixth embodiment may be applied to the first to fifth embodiments.
[100] Fig. 13 is a conceptual diagram illustrating a battery pack according to the sixth embodiment of the present invention.
[101] Referring to Fig. 13, a battery pack 100 of this embodiment includes a battery body
10, and a PTC element 510 and a resistor 521 which are arranged on a positive electrode 11 of the battery body 10 and connected in parallel with each other. Al- ternatively, the PTC element 510 and the resistor 521 may be connected in parallel with each other on a negative electrode 12. The PTC element 510 and the resistor 521 may be connected in parallel with each other on both the positive and negative electrodes 11 and 12.
[102] Preferably, the resistor 521 and the PTC element 510 are physically connected with each other. That is, when the current flowing into the positive electrode 11 and/or the negative electrode 12 of the battery increases due to external factors, the resistor 521 is heated and the temperature thereof increases. If the temperature of the resistor 521 exceeds a predetermined temperature, the resistance of the PTC element 510 increases to cause the positive electrode 11 and/or negative electrode 12 to be electrically short- circuited. Of course, the battery pack 100 may be heated to change the resistance of the PTC element 510 such that both terminals can be short-circuited. Accordingly, if the interior of the battery is stabilized or the rapid change in current is mitigated to cause the heat applied to the PTC element 510 to be dissipated, the resistance of the PTC element 510 again decreases and thus the battery can operate in a normal state.
[103] The control module is not limited to the use in the battery pack according to the previous embodiments but may be arrange between input and output ends of a given circuit to prevent the circuit from being overheated or undergoing the extraordinary change in input power and thus to perform the stable circuit operation. In other words, it is possible to ensure the circuitry stability against the thermal change by installing the control module in electronic equipment such as a camcorder, a cellular phone or a computer.
[104] According to the present invention, it is possible to reduce production costs and adjust characteristic variations between a plurality of chips within a certain range by manufacturing the control module serving as the aforementioned battery protection circuit in the form of a single chip. Such a seventh embodiment of the present invention will now be described with reference to the accompanying drawings. A description of the seventh embodiment which overlaps those of the first to sixth embodiments will be omitted herein. Further, the seventh embodiment may be applied to the first to sixth embodiments.
[105] Fig. 14 is a conceptual diagram illustrating a battery pack according to the seventh embodiment of the present invention, and Fig. 15 is a conceptual diagram of a battery protection chip according to the seventh embodiment of the present invention.
[106] Referring to Figs. 14 and 15, a battery pack 100 according to this embodiment includes a battery body 10 having positive and negative electrodes 11 and 12, and a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature. In this case, the battery pack 100 may further include a PTC element (not shown) connected to the negative electrode 12 to block external current according to the temperature.
[107] The battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200, a switching unit 2300 for electrically connecting the first and second external electrode terminals 2100 and 2200 in response to a control voltage, a control voltage generator 2400 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 according to the temperature to generate the control voltage, and a body 2500 for packaging the switching unit 2300 and the control voltage generator 2400. Preferably, a transistor 2310 is used in the switching unit 2300.
[108] The control voltage generator 2400 includes an NTC element 2420 connected between the first external electrode terminal 2100 and a control voltage node Ql and having temperature-dependent resistance, and a resistor 2440 connected between the second external electrode terminal 2200 and the control voltage node Ql. The transistor 2310 serving as the switching unit 2300 has a collector connected to the first external electrode terminal 2100, a base connected to the control voltage node Ql between the NTC element 2420 and the resistor 2440, and an emitter connected to the second external electrode terminal 2200.
[109] Preferably, the aforementioned battery protection chip 2000 operates at a temperature of 70 to 1000C to have a current of about ImA to 2OA. The battery protection chip 2000 does not operate when the internal temperature of the battery pack 100 is lower than the temperature within the operation range. If the internal temperature of the battery rapidly rises to the operation temperature range due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, however, a current path from the first external electrode terminal 2100 to the second external electrode terminal 2200 is established to thereby prevent the overcharge, control the overcurrent and ensure the thermal stability. That is, in the present invention, an operation time point of the switching device when the current path is established between the positive and negative terminals of the battery using the voltage division between the fixed resistor and the variable resistor whose resistance varies with the temperature of the battery pack is controlled to protect the battery pack.
[110] In this embodiment, a portion of the body of the battery protection chip 2000 is brought contact with the battery body 10 such that a temperature change in the battery body 10 can be immediately sensed.
[I l l] The characteristics of the respective elements constituting the battery protection chip 2000 of the present invention are not limited to the aforementioned value, and the value may be variously changed according to the voltage and current generated in the battery body 10. [112] The aforementioned battery protection chip may be fabricated in various ways.
[113] Figs. 16 to 18 illustrate processes of manufacturing the battery protection chip according to the seventh embodiment of the present invention.
[114] As illustrated in the figures, a variety of modifications for manufacturing a battery protection chip can be provided.
[115] Referring to Fig. 16, a transistor 2310, an NTC element 2420 and a resistor 2440 are prepared. Preferably, the transistor 2310 is a bare chip element that is not wire bonded. That is, a transistor 2310 in which additional electrodes for connecting a base, an emitter and a collector of the transistor to the outside are not formed and the base, emitter and collector of the transistor are directly exposed to the outside is used. Preferably, the NTC element 2420 and the resistor 2440 are chip type elements.
[116] As shown in Fig. 16 (a), a first external electrode terminal 2100 is connected to one terminal of the NTC element 2420, and a second external electrode terminal 2200 is connected to one terminal of the resistor 2440. The transistor 2310, the NTC element 2420 and the resistor 2440 are connected to each other using wires 2301 to 2304. In other words, the collector of the transistor 2310 and the one terminal of the NTC element 2420 connected to the first external electrode terminal 2100 are connected through the first wire 2301. The base of the transistor 2310 and the other terminal of the NTC element 2420 are connected through the second wire 2302, and the base of the transistor 2310 and the terminal of the resistor 2440 are connected through the third wire 2303. The emitter of the transistor 2310 and the one terminal of the resistor 2440 connected to the second external electrode terminal 2200 are connected through the fourth wire 2304.
[117] As shown in Fig. 16 (b), a predetermined packaging process of manufacturing the battery protection chip 2000 is performed by forming the body 2500 for protecting the transistor 2310, the NTC element 2420 and the resistor 2440. In the packaging process, the transistor 2310, the NTC element 2420 and the resistor 2440 connected to each other through wires are disposed at the center of a given frame, portions of the first and second external electrode terminals 2100 and 2200 are exposed to the outside of the frame, and a liquefied epoxy or plastic material is poured into the frame and then cured to manufacture the body 2500. That is, the body 2500 may be manufactured by using any one of positive, flash, injection and semi-positive molds.
[118] Moreover, the body 2500 may be manufactured into an upper body and a lower body. Such a modification will be described with reference to the accompanying drawings. A description of the modification of this embodiment which overlaps those of the previous embodiments will be omitted herein.
[119] Referring to Fig. 17, the transistor 2310, the NTC element 2420 and the resistor
2440 are prepared. As shown in Fig. 17 (a), the transistor 2310, the NTC element 2420 and the resistor 2440 are connected to one another through the wires 2301, 2302, 2303 and 2304 to form a predetermined protection circuit. In other words, the collector of the transistor 2310 is connected to the one terminal of the NTC element 2420 through the first wire 2301, the emitter of the transistor 2310 is connected to the one terminal of the resistor 2440 through the fourth wire 2304, the other terminal of the NTC element 2420 is connected to the other terminal of the resistor 2440 through the second wire 2302, and the second wire 2302 is connected to the base of the transistor 2310 through the third wire 2303.
[120] As shown in Fig. 17 (b) and (c), the transistor 2310, the NTC element 2420 and the resistor 2440 connected through the wires 2301, 2302, 2303 and 2304 are disposed on the lower body 2510 and then connected to the first and second external electrode terminals 2100 and 2200. In other words, the first wire 2301 is connected to the first external electrode terminal 2100 through a fifth wire 2305, and the fourth wire 2304 is connected to the second external electrode terminal 2200 through a sixth wire 2306. The first and second external electrode terminals 2100 and 2200 extend to bend from a top surface of the lower body.
[121] Next, the upper body 2520 is coupled onto the top surface of the lower body 2510 on which the transistor 2310, the NTC element 2420 and the resistor 2440 are formed, to thereby complete the battery protection chip 2000.
[122] The battery protection chip of the present invention is not limited thereto, and it may be manufactured in various ways. That is, the transistor 2310, the NTC element 2420 and the resistor 2440 may be disposed on the lower body 2510, connected to one another through the wires or metal lines, connected to the first and second external electrode terminals, and then covered with the upper body for the packaging.
[123] Further, the transistor, the NTC element and the resistor may be connected to one another through additional pads and metal lines. A bump may be used as the pad. Another modification of this embodiment will be described with reference to the accompanying drawings. A description of this modification which overlaps the aforementioned descriptions will be omitted herein.
[124] Referring to Fig. 18, the transistor 2310, the NTC element 2420, the resistor 2440, the lower body 2510, and the upper body 2520 are prepared. As shown in Fig. 18 (a), a plurality of bumps 2601 to 2607 which will be connected to the transistor 2310, the NTC element 2420 and the resistor 2440 are formed on the lower body 2510, and metal lines 2701 to 2706 are then formed to connect the bump 2601 to 2607 to one another.
[125] In other words, the first to third bumps 2601, 2602 and 2603 which will be connected respectively to the collector, base and emitter of the transistor 2310 are formed on the lower body 2510, the fourth and fifth bumps 2604 and 2605 which will be connected respectively to terminals of the NTC element 2420 are formed, and the sixth and seventh bumps 2606 and 2607 which will be connected respectively to terminals of the resistor 2440 are formed. Further, there are formed the first metal line 2701 for connection between the first and fourth bumps 2601 and 2604, the second metal line 2702 for connection between the second and fifth bumps 2602 and 2605, the third metal line 2703 for connection between the second and seventh bumps 2602 and 2607, the fourth metal line 2704 for connection between the third and sixth bumps 2603 and 2606, the fifth metal line 2705 extending from the fourth bump 2604 to one end of the lower body 2510 for connection with the first external electrode terminal 2100, and the sixth metal line 2706 extending from the sixth bump 2606 to the other end of the lower body 2510 for connection with the second external electrode terminal 2200.
[126] As shown in Fig. 18 (b), the collector, base and emitter of the transistor 2310 are connected to the first to third bumps 2601, 2602 and 2603, respectively; the NTC element 2420 is connected to the fourth and fifth bumps 2604 and 2605; and the resistor 2440 is connected to the sixth and seventh bumps 2606 and 2607. The first and second external electrode terminals 2100 and 2200 are connected to the fifth and sixth metal lines 2705 and 2706, respectively. Accordingly, the protection circuit shown in Fig. 15 can be manufactured and obtained. Next, the lower body 2510 is then packaged onto the upper body 2520 to thereby complete the battery protection chip 2000 as shown in Fig. 18 (c). Preferably, a portion of each of the first and second external electrode terminals 2100 and 2200 protrudes to the outside of the body 2500 in the form of a straight line.
[127] A process of manufacturing a battery protection chip is not limited to the above description and may be implemented in various ways. Metal pads may be formed on the lower body instead of the bumps, and the transistor, the NTC element and the resistor may be soldered to the metal pads. Further, the protection circuit including the transistor, the NTC element and the resistor may be first formed on an additional PCB, packaged and then connected to the external electrode terminals, to thereby manufacture the battery protection chip.
[128] Alternatively, circuit elements including a transistor, an NTC element and a resistor may be formed on a wafer through a semiconductor manufacturing process, and then, a plurality of dies with the elements electrically connected to each other are made, packaged and connected to the external electrode terminals to thereby manufacture a battery protection chip. In the aforementioned embodiment, the individual elements are formed, connected to one another through the wires or metal lines and then packaged to manufacture a battery protection chip. However, the present invention is not limited thereto. That is, the elements constituting the battery protection chip may be formed on a single wafer, electrically connected to one another in a wafer level and connected to the outside through the bonding pads. More specifically, the transistor is formed on the wafer, and the resistor and NTC element which will be connected respectively to the base, emitter and collector of the transistor are then formed on the wafer. They are passivated, and the bonding pads serving as external electrode terminals connected to the outside are then formed. Next, the wafer is cut into die chips which in turn are packaged to manufacture a battery protection chip.
[129] The processes of manufacturing a battery protection chip according to the modifications of the present invention may be simultaneously or individually employed.
[130] In the process of manufacturing a battery protection chip according to this embodiment, the operation of the circuit is tested at a predetermined temperature after the circuit is packaged, as described above.
[131] In the test, predetermined heat and current are applied to the package and an amount of current is then measured. If the measured value falls within a predetermined range, the package is determined to be successful in the test. That is, the package is mounted in a device whose internal temperature can be adjusted, and current is applied to both terminals of the package. If the current flowing through the package is 5D or less at a temperature of 250C and several hundreds rnA or more at 8O0C, the package is determined to be successful in the test. More specifically, the package is determined to be successful in the test, when the current is greater than 100mA at a temperature of 8O0C. This is because a current of 5D or less should flow through the battery protection chip of the present invention in a normal operation such that no leakage current can be produced and a current should flow well at a temperature of 8O0C or more.
[132] The battery protection chip provided in the battery pack of the present invention is not limited to the foregoing description and may be implemented in various ways. Hereinafter, a battery pack including the battery protection chip of the first modification will be described. A description of the following modification which overlaps the previous embodiments will be omitted herein.
[133] Fig. 19 is a conceptual diagram of a battery pack according to a first modification of the seventh embodiment of the present invention.
[134] Referring to Fig. 19, a battery pack 100 according to this modification of the seventh embodiment includes a battery body 10 having positive and negative electrodes 11 and 12, and a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the temperature. The battery pack 100 further includes a PTC element 30 disposed on the negative electrode 12 to block external current according to the temperature.
[135] The battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200, a switching unit 2300 for selectively connecting the first and second external electrode terminals 2100 and 2200 of the chip in response to a control voltage, a control voltage generator 2400 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 according to the temperature to generate the control voltage, and a body for packaging the switching unit 2300 and the control voltage generator 2400. The control voltage generator 2400 includes an NTC element 2420 and a first resistor 2440 connected between the first and second external electrode terminals 2100 and 2200. The switching unit 2300 includes a transistor 2310 and a second resistor 2320 connected between the first and second external electrode terminals 2100 and 2200.
[136] A connection relationship of the elements constituting the control voltage generator
2400 and the switching unit 2300 will be generally described.
[137] An internal circuit of the battery protection chip 2000 includes a transistor 2310 of which collector is connected to the first external electrode terminal 2100, an NTC element 2420 connected between the base of the transistor 2310 and the first external electrode terminal 2100, a first resistor 2440 connected between the base of the transistor 2310 and the second external electrode terminal 2200, and a second resistor 2320 connected between the emitter of the transistor 2310 and the second external electrode terminal 2200. Although it has been illustrated in Fig. 19 that the first resistor 2440 is connected between the base of the transistor and the second external electrode terminal 2200, the present invention is not limited thereto. That is, the first resistor 2440 may be connected between the base and emitter of the transistor. The battery protection chip 2000 may further include an additional capacitor between the first and second external electrode terminals 2100 and 2200. The battery protection chip 2000 may further include a capacitor connected in parallel with the NTC element 2420. The battery protection chip 2000 may further include a capacitor connected in parallel with the first resistor 2440.
[138] Preferably, the first resistor 2440 has a resistance of 0.5Ω to 2D and the second resistor 2320 has a resistance of 10 to 50Ω. At this time, a digital transistor in which the transistor 2310 and the second resistor 2320 are installed in a single chip may be employed.
[139] The second resistor 2320 may be physically connected to the second external electrode terminal 2200 which in turn is physically connected to the PTC element 30. Accordingly, when current flows through the switching unit 2300, i.e. when current flows due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, the temperature of the second resistor 2320 physically connected to the PTC element 30 rises and resultant heat is applied to the PTC element 30. Therefore, the battery body can be electrically disconnected from the outside. [140] The operation of the battery pack according to this embodiment having the aforementioned structure and characteristics will be described.
[141] In a normal operation, when a constant DC voltage is applied from the battery to the outside or when the positive and negative electrodes 11 and 12 are in a floating state, an internal temperature of the battery does not rise and the resistance of the NTC element 2420 in the battery protection chip 2000 is much greater than those of the first and second resistors 2440 and 2320. Accordingly, even though the voltage from the battery body is divided by the NTC element 2420, the first resistor 2440 and the second resistor 2320, most of the voltage is applied across the NTC element 2420. Since a voltage across the first resistor 2440 does not reach the turn-on voltage of the transistor 2310, the transistor 2310 is turned off. Accordingly, a current path is not established between the positive and negative electrodes 11 and 12. For example, if the voltage of the battery body is 4.2V, the internal temperature of the battery is 250C, the resistance of the NTC element 2420 is 10OD, the resistance of the first resistor 2440 is ID, and the resistance of the second resistor 2320 is 30Ω a voltage of about 4.16V is applied across the NTC element 2420 and a voltage of 0.04V is applied between the base and emitter of the transistor 2310, i.e. across the first resistor 2440. Since a sufficient driving voltage is not applied between the base and emitter of the transistor 2310, the transistor 2310 will be turned off.
[142] On the other hand, in a case where the internal temperature of the battery rapidly rises due to the overcharge, the external mechanical impact, the change in thermal environment, the electrical connection and the like, the resistance of the NTC element 2420 decreases due to the temperature increase. Accordingly, the voltage across the NTC element 2420 decreases and the voltage across the first resistor 2440 increases.
[143] If the internal temperature of the battery rises to a given temperature and thus a voltage across the first resistor 240 increases to the driving voltage of the transistor 2310, the transistor 2310 is turned on and a current path is established from the collector to emitter of the transistor. Accordingly, a current path is established between the positive and negative electrodes 11 and 12 of the battery such that the battery can be automatically discharged to prevent the battery from being overheated and thus exploded due to this overheating. The predetermined temperature may be an additionally set temperature or a temperature immediately before the battery pack 100 explodes. The temperature can be set by adjusting the characteristic of the NTC element 2420, the driving voltage of the transistor 2310 or the resistance of the first resistor 2440.
[144] Assume that the predetermined temperature is set to 1000C and thus the battery protection chip 2000 starts to operate at this temperature. When the internal temperature of the battery gradually rises from 250C to 1000C, the resistance of the NTC element 2420 drops to about 7.4D and a voltage of 3.7V is applied across the NTC element 2420. On the other hand, a voltage (operation voltage) of 0.5 V is applied across the first resistor 2440 and the transistor 2310 is then turned on. That is, a path along which the transistor 2310 and the second resistor 2320 are connected in series with each other is established between the positive and negative electrodes 11 and 12. Accordingly, the battery is electrically short-circuited and the battery is thus changed from a high energy state to a low energy state to thereby prevent the battery from being expanded and exploded. At this time, if the transistor 2310 is turned on, electrical current flows rapidly from the battery but is suppressed by the second resistor 2320.
[145] Further, in a case where the temperature of the battery rises due to the overcharge while the battery pack 100 is charged from an external charger 40, the current flowing through the second resistor 2320 increases the temperature of the second resistor 2320. Accordingly, the resistance of the PTC element 30 connected to the second resistor 2320 through the second external electrode terminal 2200 increases rapidly, and a terminal of the charger 40 and the battery pack 100 (negative electrode) are short- circuited to thereby block the external current and prevent the overcharge.
[146] If the battery is stabilized and the battery temperature drops due to the discharge, the resistance of the NTC element 2420 increases and thus the voltage across the first resistor 2440 decreases to allow the transistor 2410 to be turned off. Then, the battery pack 100 can be recharged and then reused.
[147] In this manner, when the battery is in a high energy state due to external factors, the battery protection chip 200 operates to cause the battery to be forcibly discharged such that the battery is in a low energy state to thereby prevent the battery from being expanded and exploded.
[148] While the NTC element operating according to the temperature to generate a control voltage (operation voltage) through the voltage division has been used in the first and second embodiments, the present invention is not limited thereto. That is, a variety of elements with temperature-dependent resistance may be employed. The element with temperature-dependent resistance may be a PTC, a CTR or the like. Further, the element is not limited to the use in the transistor 2310, but a variety of elements for performing switching operation according to the voltage change may be employed. That is, in this embodiment, a transistor 2310 serving as a switching device is controlled to be turned on and off according to the voltage division by a resistance difference between the NTC element 2420 and the first resistor 2440. Therefore, an element of which resistance decreases as the temperature rises is preferably used as the NTC element 2420, while an element of which resistance increases as the temperature rises is preferably used as the first resistor 2440.
[149] Further, the battery pack of the present invention may include a chip capable of protecting the battery against the overcharge and overcurrent as well as ensuring the thermal stability. Such a second modification of the seventh embodiment will be described with reference to the accompanying drawing. A description of the following modification which overlaps those of the previous embodiments will be omitted herein.
[150] Fig. 20 is a conceptual diagram of a battery pack according to a second modification of the seventh embodiment of the present invention.
[151] Referring to Fig. 20, a battery pack 100 includes a battery body 10 which has positive and negative electrodes 11 and 12 and can be charged and discharged, a battery protection chip 2000 for selectively connecting the positive and negative electrodes 11 and 12 according to the change in current/voltage from the battery body 10, and a PTC element 30 physically connected to a portion of the battery protection chip 2000 to block external current according to the temperature.
[152] Further, the battery protection chip 2000 includes a switching unit 2300 and a control voltage generator 2400. The battery protection chip 2000 includes first and second external terminal electrodes 2100 and 2200 connected respectively to the positive and negative electrodes 11 and 12.
[153] The circuit of the battery protection chip 2000 will be described.
[154] The battery protection chip 2000 includes a transistor 2310 of which collector is connected to the first external terminal electrode 2100, a third resistor 2460 connected between a base of the transistor 2310 and the first external terminal electrode 2100, a fourth resistor 2480 connected between the base and emitter of the transistor 2310, and a second resistor 2320 connected between the emitter of the transistor 2310 and the second external terminal electrode 2200.
[155] Hereinafter, the operation of the aforementioned battery pack will be described.
[156] When a voltage of the battery pack 100 is in a normal state by means of the general charge, the voltage is divided by the third and fourth resistors 2460 and 2480 of the battery protection chip 2000 connected to the battery pack 100 and a voltage insufficient to drive the transistor 2310 is then applied between the base and emitter of the transistor 2310 to cause the transistor 2310 to be turned off. Accordingly, no current path is established between the positive and negative electrodes 11 and 12 of the battery pack 100. However, when the voltage of the battery pack 100 is beyond the normal state due to the overcharge, the voltage is divided by the third and fourth resistors 2460 and 2480 and a voltage sufficient to drive the transistor 2310 is applied between the base and emitter of the transistor 2310 to cause the transistor 2310 to be turned on. Since the transistor 2310 is turned on, a current path is established between the positive and negative terminals 11 and 12 of the battery pack 100 to cause the battery body 10 to be forcibly discharged. In this manner, the battery current is discharged to drop the battery voltage. At this time, if the transistor 2310 of the battery protection chip 2000 is turned on, the second resistor 2320 controls the rapid current flow. Further, since the temperature of the second resistor 2320 rapidly rises, the resistance of the PTC 30 physically connected to the second resistor 2320 rapidly increases to block a current path toward the terminal of the external charger 40 such that the battery cannot be charged any longer.
[157] Assume that when a maximum target voltage of the battery pack 100 is 4.3V and the operation voltage of the transistor 2310 is 0.5V, the resistance of the third resistor 2460 is 304D, the resistance of the fourth resistor 2480 is 4OD and the resistance of the second resistor 2320 is 30Ω.
[158] When the voltage of the battery pack 100 is 4.3V or less due to the normal charge, it is divided by the second, third and fourth resistors 2320, 2460 and 2480 such that a voltage of 3.799V or less is applied across the third resistor 2460, a voltage of 0.499V or less is applied across the fourth resistor 2480 and a voltage of 0.0003V or less is applied across the second resistor 2320. That is, since a voltage of 0.5V or less is applied across the fourth resistor 2480 connected between the emitter and base of the transistor 2310, the transistor 2310 is turned off. On the other hand, when the voltage of the battery pack 100 exceeds 4.3V due to the overcharge, a voltage of 3.799V or more is applied across the third resistor 2460 and a voltage of 0.499V or more is applied across the fourth resistor 2480. That is, since a voltage of 0.5V or more is applied across the fourth resistor 2480 connected between the emitter and base of the transistor 2310, the transistor 2310 is turned on. Accordingly, a current path is established between the positive and negative electrodes 11 and 12 of the battery pack 100 such that the current in the battery can be discharged to lower the battery voltage.
[159] As described above, since it is possible to protect the battery against the overcharge and overcurrent through the battery protection chip of this embodiment, a conventional battery protection system can be replaced with the battery protection chip of the present invention. Further, since a circuit structure is simplified, an inexpensive battery protection system can be provided. Furthermore, since the battery protection system can be manufactured in the form of a chip, the uniformity of circuits can be improved during the mass-production thereof.
[160] In addition, the battery protection chip of this modification may be configured as a single chip into which the chips according to the first and second modifications are combined. A third modification of the seventh embodiment of the present invention will be described with reference to the accompanying drawings. A description of the third modification which overlaps those of the previous embodiments and modifications will be omitted herein.
[161] Figs. 21 and 22 are conceptual diagrams of a battery pack according to the third modification of the seventh embodiment of the present invention. [162] Referring to Figs. 21 and 22, a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
[163] The battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively. The battery protection chip 2000 further includes a first transistor 2310a for dividing a voltage between the first and second external electrode terminals 2100 and 2200 by a first resistor 2440 and an NTC element 2420 of which resistance varies with the temperature and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage; a second transistor 2310b for dividing the voltage between the first and second external electrode terminals 2100 and 2200 by third and fourth resistors 2460 and 2480 and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage; and second resistors 2320a and 2320b connected between the first transistor 2310a and the second external electrode terminal 2200 and between the second transistor 2310b and the second external electrode terminal 2200, respectively. At this time, the second resistors 2320a and 2320b may be replaced with a single resistor. That is, as shown in Fig. 22, the battery protection chip 2000 may include a second resistor 2310 connected between the bases of the first and second transistors 2310a and 2310b and the second external electrode terminal 2200.
[164] In the present invention, the circuit for ensuring the thermal stability and the circuit for protecting the battery against the overcharge and overcurrent may be incorporated into a single switching device. Such a fourth modification of the seventh embodiment according to the present invention will be described with reference to the accompanying drawings. A description of the fourth modification which overlaps those of the previous embodiments and modifications will be omitted herein.
[165] Figs. 23 and 24 are conceptual diagrams of a battery pack according to the fourth modification of the seventh embodiment of the present invention.
[166] Referring to Figs. 23 and 24, a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
[167] The battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively. Further, the battery protection chip 2000 includes a transistor 2310 for establishing a current path between the first and second external electrode terminals 2100 and 2000 according to a parallel resistance value of a third resistor 2460 and an NTC element 2420 of which resistance varies with the temperature and a parallel resistance value of first resistor and fourth resistors 2440 and 2480.
[168] As shown in Fig. 24, the first and fourth resistors 2440 and 2480 may be replaced with a single resistor. That is, the battery protection chip 2000 may include a fifth resistor 2490 with the parallel resistance value of the first and fourth resistors 2440 and 2480.
[169] In the present invention, a PTC element may be arranged on the positive terminal.
Such a fifth modification of the seventh embodiment of the present invention will be described with reference to the accompanying drawing. A description of the fifth modification which overlaps those of the previous embodiments and modifications will be omitted herein.
[170] Fig. 25 is a conceptual diagram of a battery pack according to the fifth modification of the seventh embodiment of the present invention.
[171] Referring to Fig. 25, a battery pack 100 of this embodiment includes a battery protection chip 2000 connected between the positive and negative terminals 11 and 12 of the battery body.
[172] The battery protection chip 2000 includes first and second external electrode terminals 2100 and 2200 connected to the positive and negative terminals 11 and 12 of the battery body 10, respectively. Further, the battery protection chip 2000 includes a transistor 2310 for dividing a voltage between the first and second external electrode terminals 2100 and 2200 by a first resistor 2440 and an NTC element 2420 of which resistance varies with the temperature and establishing a current path between the first and second external electrode terminals 2100 and 2200 according to the divided voltage, and a second resistor 2320 connected between a collector of the transistor 2310 and the first external electrode terminal 2100.
[173] In addition, the battery pack 100 includes a PTC element 30 physically connected to the first external electrode terminal 2100 to control the current flowing through the positive terminal 11. In this manner, when the overheating/overcharge/overcurrent is produced in the battery, the battery can be electrically disconnected from an external circuit connected thereto by arranging the PTC element 30 on the positive terminal 11.
[174] Hereinafter, a swelling test and a hot box test were performed on a battery pack including the battery protection chip according to the first modification of the seventh embodiment. Here, a lithium- ion battery with an operating voltage of 4.2V and a current capacity of 100OmAh was used as the battery body. A 1.24W-2.5V P-channel MOFET with a threshold voltage of 0.45V was used as the transistor. The first resistor has a resistance of 2OD, the second resistor has a resistance of 10Ω and the NTC element has a resistance of 875D at 250C and a resistance of 76.2D at 850C.
[175] Table 1 shows test results obtained from the swelling test and the hot box test conducted on the battery pack including the battery protection chip.
[176] Table 1
Figure imgf000031_0001
[177] In the swelling test, the battery pack temperature is increased from the room temperature to 850C at a rate of about 5°C/min and kept for about four hours, and then decreased to the room temperature at a rate of about 5°C/min. Throughout seven tests, it has been measured that the rates of change before and after the tests are conducted are all 3% or less, as shown in Table 1.
[178] In the hot box test, the temperature is increased from the room temperature to 15O0C at a rate of about 5°C/min and kept for about 10 minutes, and then decreased to the room temperature at a rate of about 5°C/min. At this time, it is determined whether the battery pack has been burnt. It can be seen that the battery packs according to the present invention were not burnt at all.
[179] Further, it can be seen that the current is 4.5 to 5D at the room temperature (about 250C), i.e. the current does not substantially flow, whereas the current is increased to 113 to 150mA at about 850C.

Claims

Claims
[1] L A battery protection chip, comprising: first and second external electrode terminals; a switching unit for selectively connecting the first and second external electrode terminals according to a control voltage; a control voltage generator for dividing a voltage between the first and second external electrode terminals according to a temperature to generate the control voltage; and a body for packaging the switching unit and the control voltage generator.
[2] 2. The battery protection chip as claimed in claim 1, wherein the switching unit includes a transistor which has a collector and an emitter connected to the first and second external electrode terminals, respectively, and operates according to the control voltage.
[3] 3. The battery protection chip as claimed in claim 2, further comprising a resistor connected between the first external electrode terminal and the collector of the transistor or between the second external electrode terminal and the emitter of the transistor, wherein the resistor is connected to the first or second external electrode terminal.
[4] 4. The battery protection chip as claimed in claim 1, wherein the control voltage generator comprises: a first voltage dividing means connected between the first external electrode terminal and a control voltage node; and a second voltage dividing means connected between the second external electrode terminal and the control voltage node.
[5] 5. The battery protection chip as claimed in claim 4, wherein each of the first and second voltage dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a voltage dividing resistor element, a varistor, and a Zener diode, each having a temperature-dependent resistance characteristic.
[6] 6. A method of manufacturing a battery protection chip, comprising the steps of:
(a) providing a switching device, a voltage dividing element, and first and second external electrode terminals;
(b) electrically connecting and packaging the switching device, the voltage dividing element and the first and second external electrode terminals with one another such that a voltage between the first and second external electrode terminals is divided according to a temperature and the first and second external electrode terminals is selectively connected with each other according to the divided voltage; and
(c) testing the packaged and electrically connected circuit elements to detect failure.
[7] 7. The method as claimed in claim 6, wherein the switching device is a transistor, and the voltage dividing element is at least one selected from the group consisting of an NTC element, a PTC element and a voltage dividing resistor element, each having a temperature-dependent resistance characteristic.
[8] 8. The method as claimed in claim 6, wherein step (b) comprises the steps of: connecting the voltage dividing element and the switching device between the first and second external electrode terminals through wires and connecting one end of the voltage dividing element and the switching device through a wire; and packaging the voltage dividing element and the switching device.
[9] 9. The method as claimed in claim 6, wherein step (b) comprises the steps of: preparing upper and lower bodies; arranging the switching device and the voltage dividing element within the lower body and disposing first and second external electrode terminals onto both ends of the lower body, respectively; connecting the switching device, the voltage dividing element and the first and second external electrode terminals through wires; and sealingly coupling the upper body onto the lower body with the wire-connected switching device and voltage dividing element arranged thereon.
[10] 10. The method as claimed in claim 6, wherein step (b) comprises the steps of: preparing upper and lower bodies; forming pads to be connected with the switching device and the voltage dividing element on the lower body and then electrically connecting the pads; connecting the switching device and the voltage dividing element to the pads to be electrically connected to the first and second external electrode terminals; and coupling the upper body onto the lower body to package the switching device and the voltage dividing element.
[11] 11. A battery pack, comprising: a battery body having positive and negative electrodes; and a battery protection chip operating to selectively connect the positive and negative electrodes according to a temperature.
[12] 12. A battery pack, comprising: a battery body having positive and negative electrodes; a voltage dividing means for dividing a voltage from the battery body; and a control module including a switching means operating to establish a current path between the positive and negative electrodes according to the voltage divided by the voltage dividing means.
[13] 13. The battery pack as claimed in claim 12, wherein the voltage dividing means comprises at least two dividing means between the positive and negative electrodes connected in series with each other, and the dividing means is at least one selected from the group consisting of an NTC element, a PTC element, a varistor, a Zener diode, a dividing resistor element.
[14] 14. The battery pack as claimed in claim 12, wherein the switching means includes a transistor which has a collector connected to the positive electrode and an emitter connected to the negative electrode and operates with the voltage dividing means.
[15] 15. The battery pack as claimed in claim 14, further comprising: a current control resistor connected between the emitter of the transistor and the negative electrode or between a collector of the transistor and the positive electrode; and a temperature control switch brought into physical contact with the current control resistor to control a current path through the negative or positive electrode.
[16] 16. A battery pack, comprising: a battery body having positive and negative electrodes; and a PTC element and a heating element connected in parallel with each other on the positive electrode.
[17] 17. A battery pack, comprising: a battery body having positive and negative electrodes; and a PTC element and a heating element connected in parallel with each other on the negative electrode.
PCT/KR2006/001287 2005-04-08 2006-04-07 Circuit and chip for protecting battery, method of manufacturing the same and battery pack having the same WO2006115342A1 (en)

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EP4016705A4 (en) * 2019-09-03 2023-02-22 Lg Energy Solution, Ltd. Battery pack, and battery rack and power storage device comprising same
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EP4068559A1 (en) * 2021-03-29 2022-10-05 Goodrich Lighting Systems GmbH & Co. KG Electric aircraft emergency power supply module

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