JP5094301B2 - Pack battery control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for controling a battery pack, which is not abnormally heated due to failure of ohmic-resistance heating type fuse. <P>SOLUTION: The battery pack A comprises: a switching element SWH which is switched from off to on when a battery pack A containing a secondary battery 1 comes into an abnormal state; a heating resistor R which is connected in series to the battery 1 and the switching element SWH and through which a current flows when the switching element SWH turns it on; and a resistance heating type fuse 10 which is arranged at a position where it is heated with the heating resistor R which the current flows, is connected in series to the battery 1, and comprises a fuse H that shields a current that flows the battery when fused and cut by the heating resistor R that becomes hot when the current flows. The switching element SWH is changed from off to on during a specified period of time when it comes into an abnormal state. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention relates to a method for controlling a battery pack.

The following Patent Documents 1 and 2 disclose detection of various battery abnormalities, such that secondary batteries deteriorate, characteristics of each battery greatly vary, or one of the batteries is short-circuited. The fuse connected in series to the battery is detected by being in a state where it cannot be used, and the current is passed through a heating resistor disposed at a position where the fuse can be heated, thereby fusing the fuse. It describes that the battery pack cannot be used. Patent Document 2 describes that the current flowing through the heating resistor is controlled to a constant current to optimize the heating current. And the resistance heating type fuse which combined such a fuse and heating resistance is already marketed.
Japanese Patent Laid-Open No. 9-261883 JP 2000-340267 A

  In such a battery pack, the following problems may occur when a current is passed through the heating resistor in order to melt the fuse by heat when the battery is abnormal.

  If there is a defect in the resistance heating fuse itself, the fuse is not blown when energized, the heating resistance abnormally generates heat, the battery pack is heated abnormally, and the resin case outside the battery pack is melted. There was a case.

  The present invention has been made to solve such problems, and provides a method for controlling a battery pack in which the battery pack is not heated abnormally due to a failure of a resistance heating type fuse. Objective.

  The present invention provides a switching element that is switched from off to on when a battery pack including a secondary battery is in an abnormal state, and is connected in series to the switching element and the battery so that the switching element is turned on and current flows. The heating resistor is disposed at a position heated by the heating resistor through which the current flows, and is connected in series with the battery, so that the current flowing through the battery is cut off by being melted by the heating resistor that is heated by the flowing current. In a battery pack comprising a resistance heating type fuse comprising a fuse, the switch element is turned on from off for a predetermined time when the abnormal state occurs.

  The present invention also provides a switching element that is switched from off to on when the battery pack including the secondary battery is in an abnormal state, and is connected in series to the switching element and the battery, and the switching element is turned on to supply current. The heating resistor through which the current flows and the current heated by the heating resistor through which the current flows are connected in series with the battery, and the current flowing through the battery after being blown by the heating resistor that is heated by the current flows and becomes hot In a battery pack comprising a resistance heating type fuse composed of a fuse to be cut off, including a temperature detection element thermally coupled to the fuse, and when the abnormal state occurs, the switch element is turned on from off, When a current is passed through the heating resistor and the temperature detected by the temperature detector exceeds a predetermined value, the switch element is turned off to turn off the current. Characterized in that it stop.

  In the present invention, when an abnormal state occurs, a current is passed through the heating resistor for a predetermined time. Therefore, even if the resistance heating type fuse itself is defective and the fuse is not blown, the heating resistor may generate heat abnormally. Absent.

  In addition, when an abnormal state occurs, a current is supplied to the heating resistor, and the current is stopped when the temperature detected by the temperature detection unit exceeds a predetermined value. Therefore, the resistance heating type fuse itself has a problem and the fuse is not blown. Even in this case, the heating resistance does not generate heat abnormally.

  Embodiments of the present invention will be described in detail with reference to the drawings. First, the circuit configuration, operation, and function of the battery pack A according to the embodiment of the present invention will be described with reference to FIG. 1, and then the features of the present invention will be described. As shown in FIG. 1, the present embodiment includes a battery pack A and a portable device PC that is an electronic device including a power source for charging the battery pack A. The portable device PC is a portable personal computer such as a notebook computer. The battery pack A usually has a structure that is detachably attached to the portable device PC. The portable device PC is supplied with DC power output from an adapter (not shown) that converts AC commercial power from the outlet into DC power. S is provided. The power output from the control / power supply means S is used to charge the battery pack A or is supplied to the load L of the portable device PC. When power is not supplied from commercial power, power is supplied from the battery pack A to drive the power supply circuit S and the load L.

  In the battery pack A, a secondary battery 1 such as a lithium ion battery or a nickel metal hydride battery, a current detection unit 2 including a resistor or the like for detecting a current during charging / discharging of the battery 1, and charging / discharging of the battery 1 are monitored. And a microprocessor unit (hereinafter referred to as MPU) for control. In the battery pack A, a temperature detection unit 3 including a thermistor disposed in close contact with the battery 1 is provided.

  In the present embodiment, as shown in the figure, the battery 1 is formed by electrically connecting battery cells 11, 12, 13, battery cells 21, 22, 23, and battery cells 31, 32, 33 in parallel in a block P1. , P2, and P3, and these blocks P1, P2, and P3 are connected in series. In such electrical connection, tabs, which are flat metal pieces, are connected to the positive electrode and negative electrode of the battery cell by spot welding or the like, and are electrically connected. In the case of a lithium ion secondary battery, a battery cell having a capacity of about 2000 mAh / cell is used.

  In the MPU, the total battery voltage (measurement point d), the voltages of the blocks P1 to P3, the output from the current detection unit 2, and the analog voltage of the output from the temperature detection unit 3 are input, converted into a digital voltage, and the actual voltage [ An A / D conversion unit 4 is provided for conversion into mV], actual current value [mA], or the like. Then, the output from the A / D conversion unit 4 is input to a charge / discharge control / calculation unit 5 as a control means, and calculation, comparison, determination, etc. are performed, and a signal from the control / calculation unit 5 is used. The control element 7 composed of a switching transistor or the like is on / off controlled.

  In other words, the control / calculation unit 5 calculates the remaining capacity by accumulating the charge / discharge current, detects the full charge of the battery 1, detects the abnormal current, abnormal temperature, abnormal voltage, etc. Control the discharge. The control element 7 composed of a switching transistor or the like is on / off controlled, and cuts off the current with a control signal from the control / calculation unit 5 when detecting an abnormal current, abnormal temperature, or abnormal voltage. Using a well-known technique, the control / calculation unit 5 integrates the value obtained by multiplying the charging / discharging current converted by the A / D conversion unit 4 by a measurement unit time (for example, 250 msec), and the value is satisfied at the time of discharging. The integrated amount is subtracted from the charge, or, at the time of charging, the integrated amount is added from the remaining capacity at the start of charging. By such calculation, the remaining capacity (Ah) of the battery 1 is calculated. Instead of the remaining current accumulated capacity, the accumulated power (Wh) obtained by integrating the value obtained by multiplying the voltage at the time of measurement, the current, and the measurement unit time may be used as the remaining capacity.

  The control / calculation unit 5 records various data in a memory. A control / arithmetic unit 5 including a CPU (Central Processing Unit) includes various memories. A program memory for storing a program for controlling the operation of the battery pack A is provided, and the program memory is a nonvolatile storage medium. A ROM (Read Only Memory) stores data necessary for executing the program in advance. A RAM (Random Access Memory) temporarily stores a part of a program and various data. In addition, EEPROM (Electrically Erasable Programmable ROM) or FlashMemory is provided as non-volatile memory, and EEPROM or FlashMemory needs to be saved even if software or setting data executed by the CPU or MPU shuts down. Data (for example, learning capacity, number of cycles, data at the time of abnormality, etc.) and the like are stored before shutdown, and these can be rewritten as needed.

  Furthermore, the control / arithmetic unit 5 includes various timers and counters, and is used for time measurement, frequency measurement, and the like.

  Further, in the control / calculation unit 5, when the battery 1 is a nickel metal hydride battery or the like, the peak voltage is detected, the battery voltage −ΔV (= voltage drop) is detected, and the full charge is detected. It is detected by a known method such as using the remaining capacity. When the battery 1 is a lithium ion battery, it uses constant current (MAX current 0.5-1C) / constant voltage (MAX4.2V / cell) charging with regulated current and voltage. When the condition is below the predetermined value, the battery is fully charged. When the full charge is detected, the control / calculation unit 5 outputs information indicating that the remaining capacity is 100%. The full charge information can also be transmitted to the electronic device via the communication line.

  Here, the control / arithmetic unit 5 is a control element 7 for cutting off the charging current and the discharging current, the charging FET element 71 being a p-channel FET as the charging control element, and the discharging control element. A signal for on / off control is issued to the discharging FET element 72 which is a p-channel FET. Instead of the p-channel FET, it is also possible to use an n-channel FET charging FET element and a discharging FET element using a charge pump. 74 uses a p-channel FET.

  In the control / arithmetic unit 5, when the voltage of the battery 1 becomes lithium ion or more and becomes an overcharge voltage or more (for example, 4.2 V or more), an off signal (element Since 71 is applied to the gate of the p-channel FET, the voltage of the off signal is equivalent to a high voltage signal) from the port CH. When the voltage of the battery 1 becomes equal to or lower than the overdischarge voltage (for example, 2.7 V / Cell or lower), an off signal (the element 72 is applied to the gate of the p-channel FET) to turn off the discharging FET element 72. In order to apply, the voltage of the off signal is equivalent to the signal of the high voltage) from the port DSC. As described above, since the voltage is applied to the gates of the p-channel FETs of the elements 71 and 72, the voltage of the off signal corresponds to a high voltage signal, and the voltage of the on signal corresponds to a low voltage signal. . In the overcharged state, charging is stopped by the control / calculation unit 5 issuing an off signal to the port CH. At this time, when the portable device PC is discharged, the DSC is an ON signal, so that the discharging FET element 72 can be discharged through the parasitic diode 71B of the charging FET element 71 in the OFF state. In the overdischarge state, the discharge is stopped by the control unit 5 issuing an off signal to the port DSC. At this time, when the portable device PC is charged, CH is an ON signal, so that the charging FET element 71 is in the ON state and can be charged via the parasitic diode 72B of the discharging FET element 72 in the OFF state.

  Further, in the battery pack A of the present embodiment, when the lithium ion battery 1 is held in the state of the overdischarge voltage or lower, the battery is preliminarily charged with the reduced current value instead of the above-described normal charging. A preliminary charging circuit 73 is provided. The preliminary charging circuit 73 includes a resistor 75 for reducing the charging current and a preliminary charging FET element 74 controlled by an on / off signal from the port PCH according to an instruction from the control / calculation unit 5. When the battery voltage at the time of disclosure of charge is equal to or lower than the overdischarge voltage, the control / calculation unit 5 issues an off signal from the port CH to turn off the charging FET element 71 by such a precharge circuit 73. An on signal is issued from the port PCH to turn on the precharging FET element 74. When a charging current is supplied from the portable device PC by such an operation, the charging current is reduced by the resistor 75, and the battery 1 is charged via the precharge FET element 74 in the on state. If the battery voltage becomes equal to or higher than a predetermined value (for example, 3.0 V / cell) within a predetermined time (for example, 90 minutes) from the start of charging, the control / calculation unit 5 turns off the precharging FET element 74. Then, the charging FET element 71 is turned on to perform normal charging as described above. In addition, if the battery voltage is less than a predetermined value (for example, 3.0 V / cell) within a predetermined time (for example, 90 minutes) from the start of charging, it is determined that the battery has deteriorated and cannot be charged normally and is abnormal. , Stop charging. Such abnormality determination result is appropriately transmitted to the mobile device PC side by communication processing. As for the precharge circuit 73 in the battery pack A, the precharge circuit 73 in the battery pack may be eliminated, and a precharge circuit may be provided on the PC main body side provided with the charging power source. At this time, the battery voltage of each block can obtain information from the battery pack A on the PC main body side by communication processing. The MPU also includes a communication unit 9 that transmits various battery information such as battery voltage, remaining capacity, charge / discharge current value, and various command information to the control / power supply means S of the portable device PC. Communication processing between the battery pack A and the portable device PC is performed by the communication unit 9 as follows. The communication unit 9 includes a communication data generation unit that generates various battery information such as a battery voltage, a remaining capacity, and a charge / discharge current value as signal data that can be received by the portable device PC, and a driver unit that performs actual communication. The memory in the control / arithmetic unit 5 for storing various parameters for calculating the remaining capacity and various data is used. In addition, the driver unit receives a request for transmission of various information of the battery pack from the electronic device, and transmits the data created by the communication data creation unit to the electronic device from the driver unit. As a communication system, a well-known technique such as the SMBus system can be used, and it has a function of transmitting and receiving data signals and the like via two communication lines, a data line SDA and a clock line SCL.

  Since the battery pack A is used when the commercial power cannot be used such as when being carried, the battery 1 is normally stored in a state close to full charge when the commercial power can be supplied to the portable device PC. Moreover, since the occurrence of a power failure is usually very small, the decrease in the remaining capacity of the battery 1 occurs due to the self-discharge of the battery and the power consumption in the battery pack A. The charge / discharge control / calculation unit 5 starts recharging when the remaining capacity of the battery 1 reaches the recharge capacity due to self-discharge, circuit power consumption, and the like. The recharge capacity may be obtained by subtracting the integration of the current value per predetermined time from the full charge capacity, or may be obtained from the battery voltage corresponding to the recharge capacity. Further, the recharge capacity is 90%.

  In the present embodiment, the control / calculation unit 5 performs the following process to obtain the remaining capacity. The control / arithmetic unit 5 discharges the battery 1 and subtracts the discharge capacity from the total discharge amount (= learning capacity), which is the total capacity of the battery 1 to be described later. Calculated as the integrated amount (Ah). Further, the control / calculation unit 5 calculates the remaining capacity ratio (%) of the battery 1 from the relational expression of (total capacity−integrated amount) / (total capacity) = remaining capacity ratio during discharging. The charge capacity is calculated by the integrated amount of the charge current of the battery 1 or by multiplying this by the charge efficiency. The discharge capacity is calculated in consideration of the integrated amount of discharge current or discharge efficiency. The integrating unit 5 can calculate the remaining amount by the integrated amount of electric power (Wh) instead of integrating the current. The integrated value of power is calculated by subtracting discharge power from charge power.

  Here, as the total capacity (= learning capacity) of the battery at that time, the battery 1 is completely discharged even with the accumulated capacity (Ah or Wh) of the discharge from the fully charged state to the fully discharged state. The accumulated capacity (Ah or Wh) of charging from full charge to full charge may be used. If the total capacity can be obtained by other methods, the total capacity of the battery at that time may be used.

  As the discharge proceeds, the control / calculation unit 5 corrects the remaining amount with the voltage signal input from the A / D conversion unit 4. When the A / D converter 4 receives a signal indicating that the lowest voltage among the voltages in each block has reached and decreased to the first voltage from the A / D converter 4, the control / calculator 5 The calculated remaining capacity ratio is corrected by a first remaining capacity (rate) Ya1 (for example, 8%) set in advance corresponding to the voltage (for example, lithium ion battery 3.6 V / cell).

  That is, assuming that the first remaining capacity Ya1 is 8%, the control / calculation unit 5 causes the remaining capacity until the battery voltage of the secondary battery 1 decreases to the first voltage V1 when the calculated remaining capacity reaches 9%. Hold 9% as capacity. On the other hand, when the calculated remaining capacity is 9% or more and the battery voltage of the secondary battery 1 decreases to the first voltage V1, the control / calculation unit 5 sets the calculated remaining capacity value to 8%. To correct.

  Further, when the discharge progresses and a signal indicating that the voltage of the battery 1 has decreased to a predetermined discharge end voltage is input, the control / calculation unit 5 corrects the calculated remaining amount to zero. This is because when the battery voltage decreases to the discharge end voltage, the actual capacity of the battery 1 becomes 0 as the lower limit capacity. Then, the control / calculation unit 5 calculates and stores the discharge current integrated amount from the start of discharge to the discharge end voltage as a total discharge amount (= total capacity).

  After obtaining the total discharge amount (= learning capacity), the control / calculation unit 5 uses this total discharge amount until the next total discharge amount is obtained. Further, in addition to the first voltage corresponding to the first remaining capacity (rate), the calculated remaining capacity is also calculated with the second voltage corresponding to the second remaining capacity (rate) with a smaller capacity (for example, 3%). The rate may be corrected. In addition, the first voltage, discharge end voltage, etc. corresponding to the above-mentioned remaining capacity (rate) depend on the current and temperature, so it is possible to use a voltage corrected based on the current and temperature in use. is there.

  In the present embodiment, the charge / discharge control / calculation unit 5 communicates with the mobile device PC via the communication processing unit 9 when an abnormal state described later is detected. Then, in order to stop using the battery pack A, the charge / discharge control / calculation unit 5 blows the fuses H, H provided in series with the battery 1. Such a resistance heating type fuse 10 including fuses H and H is generally sold. As shown in FIG. 1, heating resistors R and R connected in parallel are provided at intermediate points of the fuses H and H, respectively. It is a connected structure. In order to cut off the fuses H and H, they are thermally coupled to the heating resistors R and R and the fuses H and H. A breaker circuit composed of a resistance heating type fuse 10 and a switching element SWH such as a FET connected in series with the resistance heating fuse 10 is connected between the positive electrode side and the negative electrode side of the secondary battery 1, and the charge / discharge control / calculation unit 5 In this configuration, the gate signal of the switching element SWH is controlled. When the abnormal state is detected, when the charge / discharge control / calculation unit 5 switches the switching element SWH from the off state to the on state, a current flows from the battery 1 or the portable device PC to the heating resistors R and R for heating. Therefore, the heating resistors R and R generate heat, and the fuses H and H are thermally blown. Thereby, the use of the battery pack A can be disabled thereafter.

  In the present embodiment, for example, the following abnormal states are detected. However, the present invention can also be used for other abnormalities.

* When the battery voltage exceeds a predetermined value (desirably, in the range of 4.21 to 4.40 V / cell, for example, 4.25 V / cell), it is determined as abnormal.
* When charging the battery, even if the charged capacity exceeds the specified value, it is determined that there is an abnormality when it is charged without detecting full charge. This specified value is set to a capacity of 130 to 200%, for example, 150%.
* When charging, discharging, or no current (when left as a battery pack A alone, when the portable device PC is driven with AC commercial power and the battery is not used), the temperature is a predetermined value (preferably 70 In the range of ˜90 ° C., for example, exceeding 80 ° C., it is determined as abnormal.

  * If a short-circuit or short-circuit phenomenon (= micro short-circuit) occurs in the cell, it is judged as abnormal. When there is no discharging or charging current, the voltage change in a predetermined time (about 15 minutes to 60 minutes, for example, 30 minutes) is not less than a predetermined value (about 10 to 50 mV, for example, 20 mV) in each block cell. Is judged as abnormal. In addition, during discharging and charging, in each block cell, the voltage change for a predetermined time (for example, 3 minutes) is 50 mV or more, and has changed approximately twice or more than the voltage change of other block cells. Judged as abnormal.

  * During charging, discharging, in the battery 1 in which the blocks P1 to P3 having three parallel cells are connected in series, an abnormal disconnection of one or two cells in a specific block while maintaining the serial connection of the blocks When (hereinafter referred to as “tab disconnection abnormality”) occurs, it is determined that there is an abnormality. In such a case of tab disconnection detection, if a current of 1.5A flows and the block of 3 parallel cells is out of the tab and becomes a block of 2 parallel cells, the current per cell increases and increases. The change in cell voltage also increases due to the current. For example, as an example of changes per cell during charging and discharging, when 3 parallel cells, 500 mA per cell, and when the voltage change for a predetermined time (for example, 3 minutes) is 45 mV or more, 1 cell is off the tab If this occurs, there will be two cells, and an increased large current 750 mA will flow through each cell, so that the voltage change for a predetermined time (for example, 3 minutes) also becomes a large value (for example, 70 mV). The control / arithmetic unit 5 detects this voltage change and detects an abnormality as a tab disconnection. Specifically, the control / calculation unit 5 detects a voltage change in each block, and the change in a specific block over 3 minutes is a predetermined value (for example, 50 mV) or more. When the change is about twice or more, it is determined that the tab is off.

  Next, features of the present invention will be described.

  As described above, when an abnormal state is detected, the switching element SWH is changed from the OFF state to the ON state, a current flows through the heating resistor R, the heating resistors R and R generate heat, and the fuses H and H are thermally blown. To do. However, if the resistance heating type fuse 10 itself has a defect, in the resistance heating type fuse 10 in the energized state, the fuse H is not blown, the heating resistance R abnormally generates heat, and the battery pack A is abnormally heated. The resin case (not shown) outside the battery pack A may be melted. In order to prevent this, this embodiment has the following functions.

    When the above-described abnormal state is detected, the charge / discharge control / calculation unit 5 outputs an ON signal (High signal) from the OFF signal (Low signal) to change the switching element SWH from the OFF state to the ON state. A current flows from 1 or the portable device PC to the heating resistors R and R for heating. When the control / arithmetic unit 5 changes from an off signal to an on signal, in other words, the timer starts counting from the time when an abnormal state is detected. Then, when a predetermined time elapses in the timer, the control / calculation unit 5 outputs an OFF signal from the ON signal, and switches the switching element SWH from the ON state to the OFF state. Therefore, when the fuse H is not blown, the current flowing through the heating resistor R of the resistance heating type fuse 10 is stopped. As a result, if the resistance heating fuse 10 is normal or normal, the fuse H is blown, and if the resistance heating fuse 10 is abnormal and the fuse H is not blown even when energized, the predetermined time is reached. The heating resistor R does not generate heat abnormally by stopping energization after the passage of time. As for the predetermined time set in the timer, if the resistance heating fuse 10 is normal or normal, the fuse H is surely blown by energization, and the case etc. Time that does not melt (desirably, it can be used in the range of 30 seconds to 3 minutes, for example, 90 seconds) is used.

  Next, the control method of a present Example is demonstrated for every process using the flowchart of FIG. In step S1, in the charge / discharge control / arithmetic unit 5 as the control means, when the abnormal state as described above is detected, it is determined to perform the Fuse fusing process for fusing the fuse H of the resistance heating type fuse 10. . Subsequently, in step S2, the control / calculation unit 5 outputs the Fuse fusing signal by outputting the ON signal from the OFF signal, the switching element SWH is changed from the OFF state to the ON state, the energized state, the heating resistance A current flows through R for heating.

  When the control / calculation unit 5 changes from an off signal to an on signal, in other words, the timer starts counting from the time when an abnormal state is detected, and in step 3, it is determined whether or not a predetermined time has elapsed. Is done. In the case of NO (= when the predetermined time does not elapse), the ON signal is continued until the predetermined time elapses, the switching element SWH is turned on, and a current flows through the heating resistor R. Normally, the fuse H is blown by heat generated by energization of the heating resistor R within a predetermined time.

  In step 3, if Yes (= when a predetermined time has elapsed), in step 6, the control / calculation unit 5 outputs an off signal from the on signal to stop the Fuse fusing signal, and the switching element SWH From on to off. Therefore, when the fuse H is not blown due to a defect in the resistance heating fuse 10 itself, the current flowing through the heating resistor R of the resistance heating fuse 10 is stopped.

  Next, another embodiment of the present invention will be described below with reference to FIG.

  In this embodiment, functions and configurations are added to the above-described embodiment. In the circuit configuration shown in FIG. 3, the same components as those in FIG.

  In the other embodiment, a second temperature detecting unit 43 for detecting the temperature of the resistance heating type fuse 10 is provided. The second temperature detector 43 detects the temperatures of the charging FET element 71, the discharging FET element 72, and the resistance heating fuse 10.

  The second temperature detection unit 43 includes a thermistor, and the second temperature detection unit 43 has a structure in which the resistance heating type fuse 10, the charging FET element 71, and the discharging FET element 72 are thermally coupled. For example, the arrangement structure shown in FIG. 4 can be obtained. FIG. 4 is a schematic cross-sectional view for explaining the arrangement structure of each component. A charging FET element 71 and a discharging FET element 72 are arranged on the printed circuit board 100, and a second temperature detection unit is interposed therebetween. 43 thermistors are arranged. And the resistance heating type fuse 10 is arrange | positioned on these (electrical wiring is not shown in figure). Silicone resin 101 is placed between these parts, and these parts are thermally bonded.

  The output from the second temperature detection unit 43 is input to the control / calculation unit 5 via the A / D converter 4. The control / calculation unit 5 detects the high temperature abnormal temperature based on the output from the second temperature detection unit 43, that is, when the charging FET element 71 and the discharging FET element 72 are abnormal temperature, Turn off to cut off charge and discharge currents.

  The control / calculation unit 5 detects the above abnormal state, and the charge / discharge control / calculation unit 5 outputs an ON signal (High signal) from the OFF signal (Low signal) to turn on the switching element SWH from the OFF state. When the output from the second temperature detection unit 43 detects a high temperature abnormal temperature as the temperature of the resistance heating fuse 10, the control / calculation unit 5 outputs an OFF signal from the ON signal. The switching element SWH is changed from the on state to the off state.

  Therefore, when the resistance heating fuse 10 itself is defective and the fuse H is not blown, the current flowing through the heating resistor R of the resistance heating fuse 10 is stopped. As a result, if the resistance heating fuse 10 is normal or normal, the fuse H is blown. If the resistance heating fuse 10 is abnormal and energized, the fuse H is not blown. Then, when the heating resistor R generates heat and becomes an abnormal temperature, the heating resistor R does not generate heat abnormally because the energization is stopped. Therefore, it is possible to prevent the battery pack A from being abnormally heated and melting the resin case (not shown) outside the battery pack A. The abnormal temperature at this time is set to a temperature at which the resin case does not melt (about 80 to 120 ° C.), preferably a temperature just before melting.

Next, a control method according to another embodiment will be described for each process using the flowchart of FIG. In step S11, when the above-described abnormal state is detected in the charge / discharge control / calculation unit 5 as the control means, it is determined to perform the Fuse fusing process for fusing the fuse H of the resistance heating fuse 10. . Subsequently, in step S12, the control / calculation unit 5 outputs the Fuse fusing signal by outputting the ON signal from the OFF signal, the switching element SWH is changed from the OFF state to the ON state, the energized state, the heating resistance A current flows through R for heating. Subsequently, in step 13, the control / calculation unit 5 acquires and detects the temperature from the second temperature detection unit 43 as the temperature of the resistance heating type fuse 10, and in step 14, detects the detected temperature. It is determined whether or not has exceeded a predetermined value. In the case of NO (= when the predetermined value is not exceeded), the temperature is continuously detected in step 13. In the case of YES (= when exceeding the predetermined value), in step 15,
The control / calculation unit 5 outputs the OFF signal from the ON signal, thereby stopping the Fuse fusing signal and switching the switching element SWH from the ON state to the OFF state. Therefore, when the fuse H is not blown due to a defect in the resistance heating fuse 10 itself, the current flowing through the heating resistor R of the resistance heating fuse 10 is stopped.

  In the above-described embodiment, the following functions can be added. In a battery pack having a charge / discharge amount integrating function by a microcomputer, a function of adding a main body consumption current (leakage current) lower than a discharge current value detectable by the microcomputer is added. In a conventional battery pack, when a current less than a discharge current value (discharge minimum detection current value) that can be detected by a microcomputer flows, it cannot be detected as a discharge current, and the remaining battery level cannot be subtracted. Instead of this, as a new function, the PC main unit and the battery pack are connected via the SMBus communication line, so the amount of current (or current value and time) due to leakage current can be transferred from the main unit to the battery pack at regular intervals. On the other hand, a means for notifying by communication is prepared, and the remaining amount of the battery is accurately managed by subtracting and adding the current amount notified on the pack battery side. Therefore, conventionally, even if a discharge current less than the minimum discharge detection current value flows, it cannot be detected by the assembled battery, which causes an error in the remaining battery level. By notifying the PC main body side of the amount of current consumed due to the leakage current, the remaining battery level can be managed with high accuracy.

It is a circuit block diagram of the battery pack of one Example of this invention. It is a flowchart of one Example of this invention. It is a circuit block diagram of the pack battery of the other Example of this invention. It is a schematic sectional drawing explaining the arrangement structure of each component in the other Example of this invention. It is a flowchart of the other Example of this invention.

Explanation of symbols

A Battery pack PC Mobile device (= electronic device)
S control / power supply means L load MPU microprocessor unit 1 battery 2 resistance (current detection unit)
3 Temperature Detection Unit 4 A / D Conversion Unit 5 Control / Calculation Unit 7 Control Element 71 Charging FET Element 72 Discharging FET Element 9 Communication Unit 10 Resistance Heating Fuse H Fuse R Heating Resistance SWH Switching Element 43 Second Temperature Detection Unit

Claims (2)

A switching element that is switched from off to on when the battery pack including the secondary battery is in an abnormal state;
A heating resistor connected in series to the switching element and the battery, the switching element is turned on, and a current flows,
A resistor composed of a fuse that is arranged at a position heated by a heating resistor through which current flows, and that is connected in series with the battery and that is fused by heat to a heating resistor that flows through the current and becomes hot, thereby blocking the current flowing through the battery. In a battery pack comprising a heating fuse,
A control method for a battery pack, wherein the switch element is turned on from off for a predetermined time when the abnormal state occurs. A switching element that is switched from off to on when the battery pack including the secondary battery is in an abnormal state;
A heating resistor connected in series to the switching element and the battery, the switching element is turned on, and a current flows,
A resistor composed of a fuse that is arranged at a position heated by a heating resistor through which current flows, and that is connected in series with the battery and that is fused by heat to a heating resistor that flows through the current and becomes hot, thereby blocking the current flowing through the battery. In a battery pack comprising a heating fuse,
Comprising a temperature sensing element thermally coupled to the fuse;
When the abnormal state occurs, the switch element is turned from OFF to ON, a current is passed through the heating resistor, and when the temperature detected by the temperature detection unit exceeds a predetermined value, the switch element is turned from ON to OFF. The battery is controlled by stopping the current.

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