JP2010165579A - Secondary battery pack, charger or charging circuit mounted equipment, and charging system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lithium ion secondary battery pack capable of preventing heat generation of a regulation or more and deterioration of a battery cell, even in the case a protection element of a PTC thermistor or the like for temperature compensation constituting a secondary protection circuit is disconnected from the battery cell of the temperature detection object, a charger or a charging circuit mounted equipment for charging the lithium ion secondary battery pack, and a charging system. <P>SOLUTION: A first thermistor 107 for detecting the temperature of a protection element such as a PTC thermistor 106 and a second thermistor 108 for detecting the temperature of a battery cell 101 are connected to a primary protection circuit 104, and the temperature information can be output from a signal output terminal (TH1) 112 of the first thermistor and a signal output terminal (TH2) 113 of the second thermistor provided in the lithium ion secondary battery pack 100. At the time of charging, based on the temperature information, the charger or the charging circuit mounted equipment 200 judges good/failure of the lithium ion secondary battery pack 100 and displays alarm, and continues or stops charging. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a secondary battery pack, in particular a lithium ion secondary battery pack, a charger or a charging circuit mounted device for charging electric energy thereto, and the secondary battery pack and the charger or charging circuit mounted device. It is related with the comprised charging system.

  In general, secondary battery packs, especially lithium ion secondary battery packs, are primarily protected for the purpose of preventing overheating and overheating due to events such as overcharge, overdischarge, and overcurrent, and the resulting deterioration of battery cells. Circuit and a secondary protection circuit. The primary protection circuit includes a charge / discharge control switch such as an FET (field effect transistor) that cuts off a charge / discharge current. The secondary protection circuit includes a protection element such as a PTC (Positive Temperature Coefficient) thermistor that performs temperature compensation. The charge / discharge current cutoff by the FET or the like and the temperature compensation by the protection element such as the PTC thermistor are controlled by a protection IC connected to the primary protection circuit and the secondary protection circuit. Further, a protective element such as a PTC thermistor that performs temperature compensation is generally fixed in close contact with the upper surface portion, side surface portion, or bottom surface portion of the battery cell using a double-sided tape, an adhesive, or the like.

  For example, Patent Document 1 describes that a protective element such as a PTC thermistor is fixed in close contact with the upper surface portion of a battery cell using a double-sided tape made of an insulating tape.

JP 2003-77427 A

  Hereinafter, a conventional secondary battery pack, a charger or a charging circuit mounted device, and a charging system will be described with reference to the drawings, taking a lithium ion secondary battery pack as an example.

  FIG. 2 is a block diagram showing configurations of a conventional lithium ion secondary battery pack, a charger or a charging circuit mounted device, and a charging system.

  As shown in FIG. 2, a conventional lithium ion secondary battery pack 300 includes at least a battery cell 301 having a positive electrode terminal 302 and a negative electrode terminal 303, a primary protection circuit 304 including an FET or the like that cuts off a charge / discharge current, It is composed of a secondary protection circuit composed of a temperature compensating protection element, for example, a PTC thermistor 306. The primary protection circuit 304 is connected between the positive terminal 302 and the negative terminal 303, and the secondary protection circuit is connected between the negative terminal 303 and the primary protection circuit 304, and the secondary protection circuit The PTC thermistor 306 is fixed to the battery cell 301 with a double-sided tape 305.

  Further, a predetermined portion of the lithium ion secondary battery pack 300 is charged from a charger or a charging circuit mounted device 400 or a positive electrode charge / discharge terminal (+) for discharging a direct current output from the battery cell 301. 310 and a negative electrode charge / discharge terminal (−) 311 are provided, and charging is performed via the positive electrode charge / discharge terminal (+) 310 and the negative electrode charge / discharge terminal (−) 311 of the connection connector 309. The charging current is supplied to the battery cell 301 through the primary protection circuit 304 and the secondary protection circuit. Further, the electrical energy stored in the battery cell 301 by charging passes through the primary protection circuit 304 and the secondary protection circuit, and the positive charge / discharge terminal (+) 310 and the negative charge / discharge of the connection connector 309. It is discharged via the terminal (−) 311.

  Further, the conventional charger or charging circuit-equipped device 400 includes at least a charging circuit 401 therein, and the charging circuit 401 controls charging current and charging voltage, and the battery is connected via the connection connector 309. The cell 301 is charged.

  A PTC thermistor is a circuit protection element used for temperature compensation that increases the electrical resistance suddenly at a specific temperature, that is, trips to limit the current flowing in the circuit, and detects the heat generation of the lithium ion secondary battery pack. Yes. Further, as described above, since a protective element such as a PTC thermistor needs to accurately detect the temperature of a battery cell that is a temperature detection target, a protective element such as a PTC thermistor is used as described in Patent Document 1. It is necessary to fix the battery cell so that it does not come off.

  However, the adhesive material of the double-sided tape used to fix a protective element such as a PTC thermistor, or the adhesive or deterioration of adhesiveness with the aging of the adhesive, or the impact received from the outside or the constant of the battery cell There is a problem that a protection element such as a PTC thermistor may come off from the battery cell due to deformation of the lithium ion secondary battery pack accompanying heat generation and an accurate temperature may not be detected.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a protection element such as a temperature compensation PTC thermistor constituting a secondary protection circuit from a battery cell to be temperature-detected. A secondary battery pack such as a lithium ion secondary battery pack that can prevent overheating of the battery cell and the accompanying deterioration of the battery cell even when the temperature cannot be detected accurately. An object of the present invention is to provide a charger or a charging circuit mounted device for charging the secondary battery pack, and a charging system including the secondary battery pack and the charger or charging circuit mounted device.

  That is, according to the present invention, a battery cell that stores electrical energy, and a secondary protection circuit that includes a primary protection circuit and a secondary protection circuit that detect and control events including overcharge, overdischarge, and overcurrent of the battery cell. A secondary battery pack, wherein the primary protection circuit comprises at least a first thermistor and a second thermistor, and the secondary protection circuit comprises at least a temperature compensation protection element, wherein the protection element Is attached in thermal conduction with the battery cell, and the first thermistor is in thermal contact with the protection element, and the second thermistor is in the vicinity of the protection element, A secondary battery that is configured to be in thermal contact with the battery cell and includes a signal output terminal of the first thermistor and a signal output terminal of the second thermistor. Click can be obtained.

  The secondary battery pack of the present invention is for the purpose of preventing overheating of the secondary battery pack caused by events including overcharge and overdischarge of the battery cell and overcurrent and deterioration of the battery cell due to this. In addition to the conventional protection circuit, the protection circuit is characterized by a primary protection circuit with FETs as constituent elements and a secondary protection circuit with temperature compensation protection elements as constituent elements. A first thermistor for detecting the temperature of the protection element fixed to the battery cell and a second thermistor for detecting the temperature of the battery cell in the vicinity of the protection element. What was comprised so that it might connect electrically is suitable. The secondary battery pack includes a signal output terminal for outputting signals based on temperature information detected by the first thermistor and the second thermistor, that is, a signal output terminal and a second output terminal of the first thermistor. It is preferable to provide a thermistor signal output terminal. As a result, even if the protection element of the secondary protection circuit is detached from the battery cell, the protection element cannot accurately detect the temperature of the battery cell, and temperature compensation does not function. Both the temperature information of the protection element detected by the first thermistor and the temperature information of the battery cell detected by the second thermistor functioning can be monitored via the signal output terminal. .

  According to the present invention, it is possible to obtain the secondary battery pack in which the protection element is a PTC thermistor.

  In the secondary battery pack of the present invention, it is particularly preferable to use a PTC thermistor having excellent characteristics for temperature compensation as a protective element of the secondary protection circuit of the secondary battery pack. In addition, a thermal fuse, a bimetal, or the like may be used as another protective element.

  According to this invention, the said battery cell is the said secondary battery pack which is a lithium ion secondary battery cell.

  The secondary battery pack of the present invention is particularly preferably a lithium ion secondary battery pack using lithium ion secondary battery cells having a high energy density. Lithium-ion secondary battery packs are secondary battery packs that are more likely to cause heat generation than specified and battery cell deterioration due to their higher energy density than other secondary battery packs, depending on how they are handled. is there. Therefore, in order to prevent these, it is more preferable to apply the protection circuit comprising the primary protection circuit and the secondary protection circuit according to the present invention to the lithium ion secondary battery pack.

  According to the present invention, a charger or a charging circuit mounted device that charges the secondary battery pack while controlling a charging current and a charging voltage, the signal output terminal of the first thermistor of the secondary battery pack, and Based on each temperature information output from the signal output terminal of the second thermistor, a temperature judgment circuit for judging good / bad of the secondary battery pack, a charging current and a charge for charging the secondary battery pack A charging circuit for controlling the voltage and a display unit for displaying a warning about the failure of the secondary battery pack, and when the temperature information is higher than a predetermined temperature set in advance, the charging to the secondary battery pack is stopped. Thus, a charger or a charging circuit-equipped device can be obtained.

  The charger or the charging circuit-equipped device of the present invention is a device used when charging the secondary battery pack, and at the time of charging, the first battery via the signal output terminal of the secondary battery pack In order to compare whether the temperature information acquired from the thermistor and the second thermistor, reach a predetermined temperature set in advance, and determine whether the secondary battery pack is a non-defective product The determination by the temperature determination circuit, the charging circuit for controlling the charging current and the charging voltage for charging the secondary battery pack in consideration of the determination by the temperature determination circuit, and the determination by the temperature determination circuit are poor And a display unit made up of an LED (Light Emitting Diode), a small LCD (Liquid Crystal Display), or the like that warns that and displays a message prompting replacement of the secondary battery pack. . At the same time, if the determination by the temperature determination circuit is bad, it is preferable that the charging circuit controls the charging current and the charging voltage so that the charging of the secondary battery pack can be stopped. Accordingly, it is determined whether the secondary battery pack is a good product or a defective product for a person who is charging the secondary battery pack using the charger or the charging circuit-equipped device. Information can be provided, and charging of the defective secondary battery pack can be prevented.

  According to the present invention, the secondary battery pack and a charging system comprising the charger or the charging circuit mounted device, wherein the secondary battery pack includes at least a positive electrode charging / discharging terminal, a negative electrode charging / discharging terminal, A connection connector having a signal output terminal of the first thermistor and a signal output terminal of the second thermistor, and the charger or the charging circuit-equipped device is connected to the secondary battery via the connection connector. A charging system is obtained in which the pack is charged and the charging is continued or stopped based on the determination of the temperature determination circuit.

  The charging system according to the present invention charges the secondary battery pack from the charger or the charging circuit-equipped device via a connection connector provided at a predetermined location of the secondary battery pack. The connection connector is provided with a signal output terminal of the first thermistor and a signal output terminal of the second thermistor in addition to a positive charge / discharge terminal and a negative charge / discharge terminal used for charging or discharging. The charger or the charging circuit mounted device charges the secondary battery pack from the positive electrode charging / discharging terminal and the negative electrode charging / discharging terminal, and simultaneously, from the two signal output terminals, the secondary battery pack Temperature information, specifically, temperature information of a protective element such as a PTC thermistor to which the first thermistor is attached, and temperature information of a battery cell to which the second thermistor is attached, and the temperature information Based on the above, the temperature determination circuit determines whether the secondary battery pack being charged is a non-defective product, and if it is a defective product, the charger or the charging circuit Together with the display unit of the mounting device is a warning display of "bad", the control the charging current and the charging voltage by the charging circuit stops charging, if good Conversely, it is as to continue charging. As a result, the person who is charging the secondary battery pack using the charger or the charging circuit-equipped device quickly detects that the secondary battery pack is defective and overcharges it. Therefore, it is possible to prevent heat generation exceeding the regulation of the secondary battery pack and deterioration of the battery cell due to the heat generation.

  The first thermistor and the second thermistor described here are temperature-sensitive elements whose resistance value decreases as the temperature rises, that is, the NTC thermistor, and the resistance value increases conversely as the temperature rises. It is different from the PTC thermistor which is a temperature sensitive element. The charging circuit-equipped device is an electronic device that is designed so that a secondary battery pack is built into the main body, and the built-in secondary battery pack can be directly charged from the main body through a commercial power source. For example, it refers to notebook computers and digital cameras with built-in secondary battery packs.

  With the configuration described above, the present invention has the following effects. That is, the secondary battery pack of the present invention receives temperature information from the first thermistor that detects the temperature of the protective element such as a PTC thermistor and temperature information from the second thermistor that detects the temperature of the battery cell. It is possible to output from the signal output terminal provided, and the charger or charging circuit-equipped device of the present invention determines whether the secondary battery pack is good or bad based on the temperature information, and can display it. In addition, since the charging to the secondary battery pack can be continued and stopped, a protective element such as a PTC thermistor can be obtained by using a charging system comprising the secondary battery pack and the charger or a charging circuit mounted device. Even if the battery cell is disconnected from the battery cell and the temperature compensation of the secondary protection circuit does not function, charging can be stopped immediately.

The block diagram which shows the structure of the lithium ion secondary battery pack of this invention, a charger or a charging circuit mounting apparatus, and a charging system. The block diagram which shows the structure of the conventional lithium ion secondary battery pack, a charger or a charging circuit mounting apparatus, and a charging system.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings, using examples in which lithium ion secondary battery packs are applied as secondary battery packs.

  FIG. 1 is a block diagram showing a configuration of a lithium ion secondary battery pack, a charger or a charging circuit mounted device, and a charging system according to the present invention.

  As shown in FIG. 1, a lithium ion secondary battery pack 100 of the present invention includes a battery cell 101 having at least a positive electrode terminal 102 and a negative electrode terminal 103, and a primary protection circuit 104 made of an FET or the like that cuts off a charge / discharge current. , And a secondary protection circuit including a temperature compensation protection element, for example, a PTC thermistor 106. The primary protection circuit 104 is connected between the positive electrode terminal 102 and the negative electrode terminal 103, and the secondary protection circuit is connected between the negative electrode 103 and the primary protection circuit 104, and the secondary protection circuit The PTC thermistor 106 is fixed to the battery cell 101 with a double-sided tape 105. As described above, the PTC thermistor 106 is preferably used as the protective element that constitutes the secondary protection circuit. However, for example, a thermal fuse or a bimetal may be used as another protective element.

  In addition to a charge / discharge control switch such as an FET, two thermistors, a first thermistor 107 and a second thermistor 108, are connected to the primary protection circuit 104. The temperature detection unit of the first thermistor 107 is attached to an arbitrary portion of the surface of the PTC thermistor 106 constituting the secondary protection circuit so as to conduct heat with an adhesive or the like, and the surface temperature of the PTC thermistor 106 is determined. To detect. Further, the temperature detection part of the second thermistor 108 is in the vicinity of the PTC thermistor 106, and is attached to an arbitrary portion of the surface of the battery cell 101 with an adhesive or the like so as to conduct heat, The surface temperature of the battery cell 101 is detected.

  Further, at a predetermined location of the lithium ion secondary battery pack 100, a positive electrode charge / discharge terminal (+) 110 for charging from a charger or a charging circuit-equipped device 200 or discharging a DC output from the battery cell 101 is provided. And a connecting connector 109 having a negative electrode charging / discharging terminal (−) 111, and charging is performed via the positive electrode charging / discharging terminal (+) 110 and the negative electrode charging / discharging terminal (−) 111 of the connecting connector 109. The charging current is supplied to the battery cell 101 via the primary protection circuit 104 and the secondary protection circuit. Further, the electrical energy stored in the battery cell 101 by charging passes through the primary protection circuit 104 and the secondary protection circuit, and the positive charge / discharge terminal (+) 110 and the negative charge / discharge of the connection connector 109. It is discharged via the terminal (−) 111. Further, the connection connector 109 has two signal output terminals for outputting temperature information detected by the first thermistor 107 and the second thermistor 108, that is, the signal output terminal (TH1 of the first thermistor). ) 112 and a signal output terminal (TH2) 113 of the second thermistor.

  In addition, the charger or charging circuit-equipped device 200 of the present invention is connected to the battery cell 101 of the lithium ion secondary battery pack 100 of the present invention via a connection connector 109 provided in the lithium ion secondary battery pack 100. This is a device that performs charging, and includes at least a charging circuit 201, a temperature determination circuit 202, and a display unit 203 outside.

  The charging circuit 201 controls a charging current and a charging voltage for charging the lithium ion secondary battery pack 100. The temperature determination circuit 202 outputs the output signals from the signal output terminal (TH1) 112 of the first thermistor and the signal output terminal (TH2) 113 of the second thermistor provided in the connection connector 109, that is, the first Based on the temperature information of one thermistor 107 and the temperature information of the second thermistor 108, it is determined whether or not there is a problem in the temperatures of the PTC thermistor 106 and the battery cell 101, which are temperature detection targets.

  Specifically, when the temperature information of the first thermistor 107 is “x” ° C. and the temperature information of the second thermistor 108 is “y” ° C., the temperature determination circuit 202 determines that y−x ≧ 2 ° C. That is, if the difference between the surface temperature of the PTC thermistor 106 and the surface temperature of the battery cell 101 is 2 ° C. or more, it is determined that there is a problem. Based on this determination, the charging circuit 201 connected to the temperature determination circuit 202 stops charging by controlling the charging current and the charging voltage if there is a problem.

  At the same time, the display unit 203 connected to the charging circuit 201 displays, for example, a warning display by blinking LEDs or a warning by text information such as “Battery failure!” Call attention. In addition, although the said display part 203 illustrated the case where visual warning means, such as LED, were used, it is not restricted to this, Auditory warning means, such as a buzzer, or the main body of a charger or a charging circuit mounting apparatus is used. It may be a physical warning means that vibrates.

  Thus, by forming the charging system of the present invention using the secondary battery pack of the present invention and the charger or the charging circuit mounted device of the present invention, a protective element such as a PTC thermistor of the secondary protection circuit can be obtained. Even if the temperature compensation of the secondary protection circuit does not function when the battery cell comes off, the person charging the secondary battery pack displays the warning on the charger or the charging circuit mounted device. It is possible to determine whether the battery pack is good or bad, and if it is a defective product, the charging can be stopped immediately to prevent heat generation exceeding the regulation of the secondary battery pack and the accompanying deterioration of the battery cell.

  The embodiments of the present invention have been described above using the embodiments. However, the present invention is not limited to the embodiments, and the present invention is not limited to the scope of the present invention. Included in the invention. That is, it goes without saying that the present invention also includes various variations and modifications that would be obvious to those skilled in the art.

  The present invention relates to a secondary battery pack, in particular, a rectangular lithium ion secondary battery pack, a charger such as a cradle for charging the battery pack, a charging circuit-equipped device such as a laptop computer, and a charging system using the same. It can be used in the technical field.

100, 300 Lithium ion secondary battery pack 101, 301 Battery cell 102, 302 Positive terminal 103, 303 Negative terminal 104, 304 Primary protection circuit 105, 305 Double-sided tape 106, 306 PTC thermistor 107 First thermistor 108 Second thermistor 109,309 Connector 110,310 Positive charge / discharge terminal (+)
111,311 Negative charge / discharge terminal (-)
112 First thermistor signal output terminal (TH1)
113 Signal output terminal of the second thermistor (TH2)
200, 400 Charger or charging circuit mounted device 201, 401 Charging circuit 202 Temperature determination circuit 203 Display unit

Claims (5)

A secondary battery pack comprising a primary protection circuit and a secondary protection circuit for detecting and controlling a battery cell for storing electrical energy, and an event including overcharge and overdischarge of the battery cell and overcurrent,
The primary protection circuit includes at least a first thermistor and a second thermistor,
And the secondary protection circuit comprises at least a protection element for temperature compensation,
The protective element is attached so as to conduct heat with the battery cell,
And the first thermistor is in thermal contact with the protection element,
And the second thermistor is in the vicinity of the protective element, and is configured to be in thermal contact with the battery cell,
A secondary battery pack comprising a signal output terminal of the first thermistor and a signal output terminal of the second thermistor.   The secondary battery pack according to claim 1, wherein the protection element is a PTC thermistor.   The secondary battery pack according to claim 1, wherein the battery cell is a lithium ion secondary battery cell. A charger or a charging circuit-equipped device that charges the secondary battery pack according to any one of claims 1 to 3 while controlling a charging current and a charging voltage,
Temperature determination for determining good / bad of the secondary battery pack based on the respective temperature information output from the signal output terminal of the first thermistor and the signal output terminal of the second thermistor of the secondary battery pack Circuit,
A charging circuit for controlling a charging current and a charging voltage for charging the secondary battery pack;
A display unit for displaying a warning of a failure of the secondary battery pack;
A charger or a charging circuit-equipped device having a function of stopping charging of the secondary battery pack when the temperature information is higher than a predetermined temperature set in advance. A charging system comprising the secondary battery pack according to any one of claims 1 to 3 and the charger or charging circuit-equipped device according to claim 3,
The secondary battery pack includes a connection connector having at least a positive electrode charge / discharge terminal, a negative electrode charge / discharge terminal, a signal output terminal of the first thermistor, and a signal output terminal of the second thermistor,
The charger or the charging circuit-equipped device charges the secondary battery pack through the connection connector,
The charging system characterized in that the charging is continued or stopped based on the determination of the temperature determination circuit.

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