JP2007115472A - Battery pack, battery charger, charging system, and method of detecting abnormal charging - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charging system for charging a secondary battery preventing an abnormal state and incorrect charging of a battery charger with a simple structure while communicating information of secondary battery charging between a communication part at a battery pack side and a communication part at a battery charger side, by transmitting the information like temperature, required charging voltage, charging current or the like from the communication part at the battery pack side to the communication part at the battery charger side. <P>SOLUTION: A subsistence signal is made transmitted from a communication part 32 of the battery charger 2 at every prescribed time or within a prescribed time. When the subsistence signal becomes not receivable at a communication part 22 of battery pack 1 side, a charge control/judge part 21 judges that an abnormality is generated at the battery charger, or the charging is incorrect, and turns off FETs 12, 13 intercalated in a charging passage 11 extending from the battery charger to a battery pack module 14. Accordingly, an abnormal state of the battery charger and incorrect charging at the battery charger can be prevented with a simple constitution utilizing a communication function originally owned by the battery charger 2 and the battery pack 1. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a battery pack, a charger, a charging system, and a charging abnormality detection method, and more particularly to a battery pack, a charger system, and a charging abnormality detection method that are preferably implemented for charging a lithium secondary battery that requires safety.

  As a charging system for the lithium secondary battery, for example, in an SBS (Smart Battery System) of a personal computer, a charging voltage, a charging current, and a secondary battery required from the communication unit on the battery pack side to the communication unit on the charger side Information necessary for charging the secondary battery such as temperature is communicated. Further, in this SBS, the other party can recognize the malfunction of the battery pack, the charger, and the load device that is supplying power by communication.

  On the other hand, Patent Document 1 proposes a battery pack in which a remaining capacity, a lifetime, and the like are calculated on the battery pack side and communication is performed with a load device or a charger.

Furthermore, in Patent Document 2, the microcomputer on the battery pack side determines whether or not the charging FET in the battery pack has failed. If there is a failure, the microcomputer communicates with the microcomputer on the charger side, There has been proposed a charging system that improves the safety of the battery pack by blocking the FET interposed in the charging path.
Japanese Patent No. 3428015 Japanese Patent Laid-Open No. 9-312172

  However, in the above-described conventional technologies, any countermeasures against abnormalities are taken on the charger side. On the other hand, in some regions, improper chargers that are not genuine products are available at low cost, and if such a charger matches the battery pack and the terminal, it may be possible to charge the battery pack. . For example, an abnormality may occur in the voltage conversion circuit of the charger, and charging may be possible even if a voltage higher than a specified voltage is output. Of course, in lithium secondary battery packs that require high safety, safety is ensured even on the battery pack side by turning off the charging FET on the battery pack side against overcharge or overcurrent. However, when the charger fails and an excessive voltage is applied or an excessive current is flowing in, the battery pack cannot currently handle it, and the secondary battery is subjected to great stress, resulting in a long service life. There is a problem of shrinking.

  Therefore, although the charger authenticates the ID of the battery pack and performs charging, an inappropriate product can be eliminated, but there is a problem that complicated processing is required. Further, even if the battery pack has an ID and can respond, it cannot be handled if the charger is an inappropriate product that does not have an authentication function.

  The object of the present invention is to improve the safety by preventing charging due to an excessive voltage or current with a simple configuration, and to eliminate a problem that significantly shortens the life of a normal battery pack. A battery pack, a charger, a charging system, and a charging abnormality detection method that can be performed.

  In the battery pack according to the present invention, in the battery pack in which the charging control unit controls the charging current from the charger to charge the secondary battery, a predetermined signal transmitted from the charger-side transmitting unit is transmitted. Receiving means for receiving, and when the predetermined signal is received by the receiving means, the charging control means supplies a charging current from a charger to the secondary battery, and the predetermined signal is not received. The charging current is suppressed.

  Further, the charger of the present invention transmits a predetermined signal in the charger in which the charging control means controls the charging current to charge the secondary battery in the battery pack, and receives the signal on the battery pack side. It is characterized by comprising transmitting means for recognizing whether or not the charger is operating normally based on whether or not the signal is received by the means.

  According to the above configuration, a predetermined signal is transmitted from the charger side, and the charge control means on the battery pack side determines whether the charger is abnormal or inappropriate because the signal has been received or not. It is determined whether it is a (non-regular) charger, and charging current from the charger to the secondary battery is supplied or suppressed according to the determination result. That is, the charger is also monitored from the battery pack side to prevent charging in an abnormal state or unauthorized charging. The charging current may be suppressed by turning off the FET interposed in the charging path to cut off the charging current or reducing the gate voltage to reduce the charging current.

  Therefore, with a simple configuration that only transmits and receives a predetermined signal, it is possible to improve the safety by preventing charging due to excessive voltage and current, and to significantly shorten the life of a normal battery pack Can be eliminated. In addition, it is possible to eliminate non-genuine chargers with low reliability.

  Furthermore, in the battery pack of the present invention, the predetermined signal is transmitted every predetermined time or within a predetermined time from the transmitting means on the charger side.

  According to said structure, a charger can be regularly monitored by operation | movement like what is called a watch dog timer.

  The battery pack of the present invention further includes a transmission unit, and the charge control unit transmits a signal for suppressing the charging current from the transmission unit to the charger side in conjunction with the suppression of the charging current. It is characterized by.

  According to the above configuration, the charging current is suppressed on the battery pack side as well as the charging current suppression operation on the battery pack side as described above. Even when an abnormality occurs and the charging current cannot be suppressed, the charging current can be suppressed.

  Furthermore, in the battery pack of the present invention, the transmitting means is a transmitting means for transmitting at least one of a charging voltage, a charging current, a state of a secondary battery, and charging control information requested to the charger side. And

  According to the above configuration, the charging current is suppressed on the charger side using the existing configuration for communicating information necessary for charging the secondary battery from the battery pack to the charger. Can do.

  In addition, the charging system of the present invention charges the secondary battery while communicating information for charging the secondary battery between the communication means on the battery pack side and the communication means on the charger side. In the charging system, the communication means on the charger side transmits a predetermined signal at least every predetermined time or within a predetermined time at least during the charging period, and the battery pack is transmitted within the at least charging period. The charging means includes charging control means for suppressing a charging current from the charger to the secondary battery when the predetermined signal is not received within a predetermined time by the communication means.

  Furthermore, the charging abnormality detection method of the present invention is a method for detecting an abnormality when charging a secondary battery in a battery pack with a charger. At least a charging period is set at a predetermined time by the charger. Alternatively, a predetermined signal is transmitted every predetermined time, and when the predetermined signal is not received on the battery pack side, it is determined that an abnormality has occurred in the charger or that the charger is inappropriate. It is characterized by doing.

  According to the above configuration, the communication means on the battery pack side and the communication means on the charger side such as transmitting information such as the required charging voltage and charging current from the communication means on the battery pack side to the communication means on the charger side. In the charging system and the charging abnormality detection method for charging the secondary battery while communicating information for charging the secondary battery between In the case of a normal charger, a data transmission request is sequentially transmitted from the charger side. However, in the case of a transmission abnormality or an irregular charger, charging is continued even without transmission. End up.

  On the other hand, according to the present invention, if a predetermined data request signal is not received within a predetermined time or even if the charger side is not required, a dummy is generated every predetermined time or within a predetermined time from the charger side. When the signal cannot be received, the charge control means on the battery pack side determines that the charger is abnormal or is an improper (non-regular) charger, The charging current from the charger to the secondary battery is suppressed. In other words, the charger is also monitored from the battery pack side by an operation like a so-called watch dog timer to prevent charging in an abnormal state or unauthorized charging. The charging current may be suppressed by turning off the FET interposed in the charging path to cut off the charging current or reducing the gate voltage to reduce the charging current.

  Therefore, it is possible to improve the safety by preventing charging due to excessive voltage and current with a simple configuration that uses the communication function originally possessed by the charger and the battery pack, and for the normal battery pack. It is possible to eliminate problems that significantly shorten the service life. In addition, it is possible to eliminate non-genuine chargers with low reliability.

  As described above, the battery pack and the charger of the present invention transmit a predetermined signal from the charger side, and the charge control means on the battery pack side determines whether or not the signal has been received. It is determined whether an abnormality has occurred or the charger is not appropriate (not regular), and charging current from the charger to the secondary battery is supplied or suppressed according to the determination result.

  Therefore, with a simple configuration that only transmits and receives predetermined signals, it is possible to improve safety by preventing charging due to excessive voltage and current, and significantly shorten the life of a normal battery pack. The trouble can be eliminated. In addition, it is possible to eliminate non-genuine chargers with low reliability.

  In addition, the charging system and the charging abnormality detection method of the present invention, as described above, transmits information such as the required charging voltage and charging current from the communication means on the battery pack side to the communication means on the charger side. Effective in a charging system that charges the secondary battery while communicating information for charging the secondary battery between the communication means on the pack side and the communication means on the charger side, When there is no signal for a predetermined data request, or when there is no such signal to be transmitted regularly, even if it is not necessary, the charger transmits a signal every predetermined time or within a predetermined time. When the signal cannot be received, the charging control means on the battery pack side determines that the charger is abnormal or is an inappropriate charger, and charging the secondary battery from the charger. Intervened in the pathway By, for example, OFF the ET, to suppress the charging current.

  Therefore, with a simple configuration using the communication function originally provided by the charger and the battery pack, it is possible to prevent charging due to excessive voltage and current and improve safety, and a normal battery pack Such a problem that the life of the battery is significantly shortened. In addition, it is possible to eliminate non-genuine chargers with low reliability.

  FIG. 1 is a block diagram showing an electrical configuration of a charging system according to an embodiment of the present invention. The charging system includes a battery pack 1 and a charger 2 that charges the battery pack 1. However, an electronic device system may be configured to further include a load device (not shown) that receives power from the battery pack 1. . In that case, although the battery pack 1 is charged from the charger 2 in FIG. 1, the battery pack 1 may be attached to the load device and charged through the load device. The battery pack 1 and the charger 2 are connected to each other by DC high-side terminals T11 and T21 that supply power, communication signal terminals T12 and T22, and GND terminals T13 and T23 for power supply and communication signals. . Similar terminals are also provided when the load device is provided.

  In the battery pack 1, the DC high-side charging path 11 extending from the terminal T11 includes FETs 12 and 13 having different conductivity types for charging and discharging, and the charging path 11 Is connected to the high-side terminal of the battery pack 14. A low side terminal of the assembled battery 14 is connected to the GND terminal T13 via a DC low side charging path 15, and the charging path 15 includes a current detection resistor 16 that converts charging current and discharging current into voltage values. Is intervened.

  The assembled battery 14 includes a plurality of secondary battery cells connected in series and parallel, and the temperature of the cells is detected by a temperature sensor 17 and input to an analog / digital converter 19 in a control IC 18. The voltage between the terminals of each cell is read by the voltage detection circuit 20 and input to the analog / digital converter 19 in the control IC 18. Furthermore, the current value detected by the current detection resistor 16 is also input to the analog / digital converter 19 in the control IC 18. The analog / digital converter 19 converts each input value into a digital value and outputs the digital value to the charge control determination unit 21.

  The charge control determination unit 21 includes a microcomputer and its peripheral circuits, etc., and in response to each input value from the analog / digital converter 19, a charge current for requesting an output from the charger 2. The voltage value, current value, and pulse width (duty) are calculated and transmitted from the communication unit 22 to the charger 2 via the terminals T12 and T22; T13 and T23. The charge control determination unit 21 constitutes a charge control means together with the FETs 12 and 13, and when charging / discharging is normally performed, the FETs 12 and 13 are turned on to enable charging / discharging. Is detected, charging and discharging are disabled.

  In the charger 2, the request is received by the communication unit 32 of the control IC 30, and the charge control unit 31 controls the charge current supply circuit 33 to calculate the charge current with the voltage value, current value, and pulse width. Supply. The charging current supply circuit 33 is composed of an AC-DC converter, a DC-DC converter, etc., and converts an input voltage into a voltage value, a current value, and a pulse width instructed by the charging control unit 31, and a terminal T21, T11: Supply to charging paths 11 and 15 via T23 and T13. The charge control unit 31 and the charge current supply circuit 33 constitute charge control means.

  In the charging system configured as described above, during normal charging, the charger 2 sequentially issues data transmission requests indicating the status of the battery pack, such as error information, capacity, voltage, and temperature, from the battery pack 1 side. Returns the requested data and sequentially transmits a charging voltage value, a charging current value, etc. for charging. Conventionally, even if such communication is in an abnormal state, it was not involved in charge control, whereas in the present embodiment, it is recognized that an abnormality is detected and charging is controlled. Have

  In the present embodiment, the transmission request as described above is used as a survival signal that is a predetermined signal for detecting an abnormality, and when no transmission request is generated at an appropriate timing for detecting an abnormality, the charger 2 side is not necessary. However, the charging control unit 31 is a transmission unit, and transmits the survival signal in a dummy manner every predetermined time or within a predetermined time from the communication unit 32 which is a communication unit. On the other hand, on the battery pack 1 side, when the survival signal cannot be received by the communication unit 22 that is a receiving unit and a communication unit, the charging control determination unit 21 causes an abnormality in the charger 2, It is determined that the charger is improper (not regular), and the FETs 12 and 13 are turned off.

  For this reason, in the control IC 30, the charge control unit 31 causes the communication unit 32 to receive a voltage value and a current value of the charging current transmitted from the battery pack 1 for a predetermined time, for example, every 2 seconds, and While performing the main process of supplying the corresponding charging current from the charging current supply circuit 33, the timer 34 interrupts periodically within a predetermined time, for example, every 30 seconds to 1 minute, or aperiodically within that time. And the survival signal is transmitted from the communication unit 32.

  On the other hand, in the control IC 18 of the battery pack 1, the charge control determination unit 21 responds to the first count value of the timer 23 every two seconds, as shown in FIG. Each input value is taken in (S1), and the main process is performed. In the main process, it is determined from the input values whether an abnormal state such as overvoltage, overcurrent, or overheating has occurred. If it is abnormal (YES in S2), the FETs 12 and 13 are turned off ( A signal for stopping the charging current is transmitted to the charger 2 together with S3) (S4). The signal for stopping the charging current is, for example, for setting the required charging voltage and charging current to 0, and in response to this, the charging control unit 31 causes the charging current supply circuit 33 to stop supplying the charging current. .

  On the other hand, if each of the input values is normal (NO in S2), the charge control determination unit 21 determines whether a later-described survival signal is received (NO in S5), The voltage value and current value of the charging current corresponding to each input value are calculated and transmitted to the communication unit 22 (S6).

  If the battery pack 1 side is in a normal state while performing such main processing, the charging control determination unit 21 causes the communication unit 22 to receive the survival signal, and when received, as shown in FIG. An interrupt is generated to reset and restart the second count value of the timer 23 (S11).

  Therefore, in step S5, when the second count value is predetermined, for example, when 1 minute has not elapsed, that is, when the survival signal is received in a cycle within 1 minute, the charger 2 It is determined that the product is proper and is operating normally, and the voltage value, current value, and pulse width of the required charging current are transmitted (S6). On the other hand, in the step S5, when the second count value has passed the one minute, that is, when charging is continued without receiving the survival signal for one minute, as described above. It is determined that an abnormality has occurred in the charger 2 or that the charger is an improper charger, and the FETs 12 and 13 are turned off (S3). That is, the charging control determination unit 21 monitors the charger 2 from the battery pack 1 side in an operation like a so-called watch dog timer, and an abnormality occurs between the battery pack 1 and the charger 2. To prevent charging in a state where it is present or charging with an improper (non-regular) charger.

  Therefore, the charger 2 and the battery pack 1 can improve safety by preventing charging due to excessive voltage and current with a simple configuration using the bidirectional communication function originally possessed by the charger 2 and the battery pack 1. It is possible to eliminate a problem that significantly shortens the life of a normal battery pack. In addition, it is possible to eliminate non-genuine chargers with low reliability.

  The charge control determination unit 21 transmits a signal for stopping the charging current from the communication unit 22 to the communication unit 32 on the charger 2 side in conjunction with the OFF operation (S3) of the FETs 12 and 13. (S4). Accordingly, the charging current is cut off on the battery pack 1 side when the FETs 12 and 13 are turned off, and the charging current is cut off also on the charger 2 side. Therefore, the short circuit failure of the FETs 12 and 13 on the battery pack 1 side. The charging current can be cut off even when an abnormality such as the above occurs and the charging path 11 cannot be cut off.

  In the present invention, as long as the charging current can be suppressed, the charging current may be reduced by reducing the gate voltage of the FETs 12 and 13, but the charging current is cut off by turning off the FETs 12 and 13 as described above. It is easier to control.

  Further, the charging control determination unit 21 on the battery pack 1 side calculates the voltage value, current value, and pulse width of the charging current that requires output from the voltage between terminals of each cell, the charging current, the temperature of the cell, etc. Although the information is transmitted to the charger 2 as information for charging the secondary battery, the measurement values are transmitted to the charger 2 as they are, and the charge controller 31 calculates the voltage value and the current value of the charging current. You may do it.

  Furthermore, when it is replaced with a normal and normal charger, it is necessary to charge normally, and when it is detected that the battery pack 1 is detached or inserted into the charger 2 by a detection means (not shown), or the communication is resumed. When detected, the charging control determination unit 21 is reset and can be charged normally.

  Furthermore, the survival signal may be a survival signal on the charger 2 side and the battery pack 1 side, such as a signal that becomes active for a predetermined period, a pulse in a predetermined form, and a data transmission request signal as described above. Any signal that can be recognized may be used. In addition, the state in which the survival signal is not received is a state in which the signal itself cannot be detected when the communication line is stuck to a high or low level or is in an open state. Even if it can be received, it represents both the state where the contents cannot be recognized.

  The present invention provides a charging system in which the secondary battery is charged while communicating information for charging the secondary battery between the communication unit on the battery pack side and the communication unit on the charger side. When the charger transmits a survival signal as a dummy every predetermined time or within a predetermined time, and the survival signal cannot be received, the battery pack side charge control unit generates an abnormality in the charger. Since it is determined that the charger is improper and the charging path is interrupted, charging in such a situation can be prevented with a simple configuration.

It is a block diagram which shows the electric constitution of the charging system which concerns on one Embodiment of this invention. It is a flowchart which shows the main process operation | movement of the battery pack which comprises the said charging system. It is a flowchart which shows the interruption process operation | movement of the said battery pack.

Explanation of symbols

1 Battery Pack 2 Charger 11, 15 Charging Path 12, 13 FET
14 assembled battery 16 current detection resistor 17 temperature sensor 18, 30 control IC
19 Analog / Digital Converter 20 Voltage Detection Circuit 21 Charge Control Determination Units 22, 32 Communication Units 23, 34 Timer 31 Charge Control Unit 33 Charging Current Supply Circuits T11, T21; T12, T22; T13, T23 Terminals

Claims (7)

In the battery pack in which the charging control means controls the charging current from the charger to charge the secondary battery,
Receiving means for receiving a predetermined signal transmitted from the charging means on the charger side;
The charging control means supplies the charging current from a charger to the secondary battery when the predetermined signal is received by the receiving means, and suppresses the charging current when the predetermined signal is not received. Battery pack featuring.   2. The battery pack according to claim 1, wherein the predetermined signal is transmitted from the transmission unit on the charger side every predetermined time or within a predetermined time.   3. The transmission device according to claim 1, further comprising a transmission unit, wherein the charge control unit transmits a signal for suppressing the charging current from the transmission unit to the charger side in conjunction with the suppression of the charging current. The battery pack described.   4. The battery pack according to claim 3, wherein the transmitting means is a transmitting means for transmitting at least one of a charging voltage, a charging current, a state of a secondary battery, and charging control information requested to the charger side. In the charger in which the charging control means controls the charging current to charge the secondary battery in the battery pack,
Charging characterized by comprising a transmission means for transmitting a predetermined signal and recognizing whether or not the charger is operating normally based on whether or not the signal is received by the reception means on the battery pack side. vessel. In the charging system configured to charge the secondary battery while communicating information for charging the secondary battery between the communication means on the battery pack side and the communication means on the charger side,
The communication means on the charger side transmits a predetermined signal every predetermined time or within a predetermined time at least during the charging period,
The battery pack includes a charge control unit that suppresses a charging current from the charger to the secondary battery when the predetermined signal is no longer received within a predetermined time by the communication unit within the charging period. A charging system comprising: In a method for detecting an abnormality when charging a secondary battery in a battery pack with a charger,
At least during the charging period, the charger transmits a predetermined signal every predetermined time or within a predetermined time,
When the predetermined signal is not received on the battery pack side, an abnormality occurs in the charger, or it is determined that the charger is inappropriate.

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