JP5167521B2 - Battery pack and electronic device using the battery pack - Google Patents

Description

  The present invention relates to an assembled battery or an electronic device including a charge / discharge management control unit and a battery cell abnormality detection control unit, and more specifically, includes a magnetic detection unit to detect a magnetic flux density generated by a current to be measured. The present invention relates to an assembled battery or an electronic device including a charge / discharge management control unit and a battery cell abnormality detection control unit using a small and highly accurate current sensor.

  In a conventional assembled battery, a plurality of battery cells are connected in series or in parallel, and the temperature, voltage and current of the assembled battery are detected by output signals from various sensors attached to the assembled battery, and the detection results It is configured to perform charge / discharge control and abnormality detection according to the above.

  FIG. 1 is a circuit configuration diagram showing a schematic configuration of a conventional assembled battery. As shown in FIG. 1, a battery used in a notebook personal computer or the like includes two battery cells (1a to 1c, 2a to 2c) connected in parallel, two blocks connected in series, or two battery cells. What connected in parallel 3 blocks is utilized, and in such an assembled battery, the shunt resistance 5 is normally arrange | positioned as a current sensor in the location through which all the currents flow. Reference numerals 3a and 3b denote discharge circuits, reference numerals 4a and 4b denote switches, and reference numeral 6 denotes a charge / discharge switch.

  In addition, there exists patent document 1 about charge / discharge management of an assembled battery system, for example. The device described in Patent Document 1 is configured so that charging can be appropriately controlled according to the state of the assembled battery, for example, the battery temperature, the progress of charging, and the like. In the assembled battery comprising: a current detecting means for detecting a charge / discharge current of the assembled battery; and a current detected by the current detecting means is integrated with time to add / subtract to an initial value of the battery capacity of the assembled battery. A battery capacity measuring means for obtaining a remaining capacity of the battery capacity, a battery temperature detecting means for detecting a battery temperature of the assembled battery, and a predetermined output when the remaining capacity reaches a capacity reference value corresponding to the battery temperature. And a charging device connected to both ends of the assembled battery for charging, receiving the output, and performing auxiliary charging while reducing charging current.

  However, in the assembled battery as shown in FIG. 1, when the internal impedances of the battery cells in parallel relation are different, the battery cell having a relatively low internal impedance even if the charging control of the entire assembled battery is accurately performed. A larger current flows than intended. For this reason, there was a problem that the battery cell was overcharged and the performance deteriorated.

  Moreover, there exists patent document 2 about the abnormality detection method and its abnormality detection apparatus of an assembled battery system, for example. The device described in Patent Document 2 is configured to be able to accurately detect an abnormality in any of the assembled battery blocks constituting the assembled battery system by current detection. In an assembled battery system in which a plurality of assembled battery blocks in which batteries (battery cells) are connected in series are connected in combination of a series and a parallel, each assembled battery block is provided with a current sensor for detecting the current value, and the detection result Is processed by processing the current value of each assembled battery block detected by an algorithm according to the connection form of the assembled battery block, thereby detecting an abnormality in the assembled battery block.

  However, in the assembled battery as shown in FIG. 1, even if an abnormality such as an abnormal increase in the internal impedance of one of the battery cells occurs, the current sensor 5 has only a partial effect. It is difficult to accurately detect abnormalities, and even if they can be detected, it is not immediately possible to determine which battery cell is defective, and there is a problem that appropriate measures cannot be taken easily. .

  In order to solve such a problem, the current sensor (7a-7c, 8a-8c) is placed on the current path of each battery cell to detect the current flowing through each battery cell, and the battery cells in a parallel relationship A method may be considered in which a battery cell having an abnormal internal impedance is discriminated by comparing the current values.

  For example, as in Patent Document 3, there is a method of using a shunt resistor as a current sensor. However, when a shunt resistor is used as a current sensor, a part of the electric power stored in the battery is consumed as Joule heat in the shunt resistor, so there is a problem of power loss and the battery capacity is reduced. There is a problem that the continuous use time is shortened. In particular, when a shunt resistor is arranged on the current path of each battery cell, the power loss is doubled by the number of shunt resistors. For this reason, it is not realistic to employ a shunt resistor.

  It is also conceivable to use a magnetic sensor as the current sensor. When using a magnetic sensor, the current path is usually surrounded by a magnetic core, and the magnetic sensor is disposed in the magnetic body to amplify the magnetic flux density and improve the current detection accuracy. As a current sensor using a magnetic core, for example, Patent Document 4 can be cited. The current sensor described in Patent Document 4 can reduce the number of parts to reduce the size, improve the productivity and assembly, is inexpensive and suitable for mass production, and has a U-shaped conductor and a magnetic sensor. And a current sensor having a compact configuration using only a magnetic core and a holding material. However, even in the example of Patent Document 3, the size of the current sensor is about 20 mm × 8 mm × t19 mm, and if this is used to detect the current of the battery cell, there arises a problem that the assembled battery becomes large.

  Furthermore, with the recent increase in processing speed of electronic devices, the load connected to the assembled battery may change at a high frequency. In such a case, the current flowing through each battery cell also changes with time at high speed.For example, when the current of each battery cell is sequentially sampled by the current sensor, a different current is detected depending on the sampling start time of each current sensor, Even in a normal state in which the internal impedances of the battery cells are aligned, there is a problem that it is determined as abnormal.

JP-A-8-163786 JP 2003-142165 A JP 2003-513596 A International Publication WO2003 / 046584 Pamphlet

  The present invention has been made in view of such problems, and an object of the present invention is to be able to configure an assembled battery that can be reduced in size and has no power loss, and to detect currents of a plurality of battery cells that constitute the assembled battery. Providing a suitable magnetic current sensor capable of detecting multiple currents to be measured at the same time, which enables accurate charge / discharge management, and when an abnormality occurs in any of the battery cells that make up the battery pack Another object of the present invention is to provide an assembled battery or an electronic device provided with an abnormality detection control unit that can accurately detect it.

  The present invention has been made in order to achieve such an object, and the invention according to claim 1 is an assembled battery in which a plurality of battery cells are used, and the battery cells are connected in series and in parallel. A first current sensor for detecting a current flowing through each battery cell, wherein the first current sensor includes a magnetic detection unit, a sampling processing unit that samples an output signal of the magnetic detection unit, and an external trigger. A trigger detection unit that detects a signal and a hold processing unit that holds an output signal of the magnetic detection unit, and drives the magnetic detection unit and the sampling processing unit in synchronization with the external trigger signal; The output signal of the magnetic detection unit sampled by the sampling processing unit is held by the hold processing unit.

  By adopting a method in which the current value is detected by detecting the magnetic flux density generated by the flow of current using a magnetic detector, a power loss is a problem in the method of detecting resistance by inserting a resistance into a non-measurement current path that uses a shunt resistor. Can solve the problem.

  Further, by driving the current sensor by an external trigger, even when a plurality of the current sensors are used, the sampling process of the output signal is synchronized for all the magnetic detection units, and the current value of each current path at the same time is Comparison is possible. Further, since the current sensor is not driven while current detection is not performed, current consumption can be reduced and power loss can be suppressed.

  When sampling processing of the output signal of the magnetic detection unit is performed at the same time, in order to process this output signal, it is necessary to simultaneously capture the output signal. For this reason, normally, the same number of A / D converters as outputs are required, and the processing circuit becomes large. However, the current sensor employed in the present invention introduces a hold processing unit that keeps the output signal. This eliminates the need to capture output signals at the same time. In this case, since the output signal can be sequentially taken in by one A / D converter, the processing circuit can be downsized.

  As for the current sensor employed in the present invention, it is naturally possible to read the output sequentially with the output signal being a digital value instead of an analog value.

  According to a second aspect of the present invention, in an assembled battery in which n battery blocks in which m battery cells are connected in parallel are connected in series (m and n are positive integers), A second current sensor for detecting a current value; and a first current sensor for detecting a current flowing in any (m−1) battery cells in each battery block, wherein the first current The sensor has a magnetic detection unit, a sampling processing unit that samples the output signal of the magnetic detection unit, a trigger detection unit that detects an external trigger signal, and a hold processing unit that holds the output signal of the magnetic detection unit. The magnetic detection unit and the sampling processing unit are driven in synchronization with the external trigger signal, and the output signal of the magnetic detection unit sampled by the sampling processing unit is held by the hold processing unit. To.

  Also in the conventional assembled battery, what has the shunt resistance which detects the electric current value of the whole assembled battery is common (2nd current sensor). The present invention uses the shunt resistance to detect the current values of (m−1) battery cells without providing a current sensor for each battery cell, thereby detecting the current values of all the battery cells. Can be obtained by calculation. Since the number of current detection means can be reduced, it is suitable for reducing the size of the assembled battery.

The invention according to claim 3 is the invention according to claim 1 or 2, wherein each of the first current sensors is disposed in the vicinity of a current path of each battery cell. is there.
The magnetic flux density generated around the current path generally increases as it approaches the current path. In order to increase the output of the magnetic detection unit, the current sensor is preferably disposed near the current path, for example, within 0.2 mm from the current path.

  The invention according to claim 4 is the charge / discharge management control for performing charge / discharge management of the assembled battery using the output value of each first current sensor in the invention according to claim 1, 2 or 3. It is characterized by having a section.

  As a method of charging the battery pack, when the battery cell voltage is low, the battery is charged with a constant current, and after the battery cell voltage reaches a predetermined threshold, charging is performed at a constant voltage, and the charging current reaches a predetermined threshold. A constant current and constant voltage system that is fully charged at the time is known. By performing current detection on each battery cell, it is possible to perform charge current management so that the charge current does not exceed a predetermined threshold value in each battery cell even when the current flowing through each battery cell varies.

  The assembled battery of the present invention is particularly suitable for charge / discharge management of a lithium ion secondary battery that requires particularly strict voltage and current management during charge / discharge.

  Further, when the assembled battery is discharged, the discharge current of each battery cell can be calculated individually by detecting the current flowing through each battery cell and integrating each of them with the discharge time. For this reason, even when there is variation in the internal impedance of each battery cell, it is possible to accurately predict the remaining amount of the assembled battery.

  According to a fifth aspect of the present invention, in the invention according to any one of the first to fourth aspects, a predetermined process according to a connection form of the assembled battery from an output value of each first current sensor, An abnormality detection control unit that detects that there is an abnormality in any of the battery cells of the assembled battery is provided.

  When an abnormality occurs in any one of the battery cells, it can be accurately detected and dealt with by current detection. Furthermore, it is possible to specify the battery cell in which an abnormality has occurred.

  That is, in an assembled battery in which a plurality of battery cells connected in parallel are connected in series, battery abnormality occurs when the difference in current value between the battery cells in parallel relationship exceeds a predetermined threshold (first threshold). Alternatively, the current detection means is abnormal, and when the difference in the current value between the battery cells connected in series exceeds a predetermined threshold (second threshold), the current detection means is abnormal. It is possible to determine the abnormality of the assembled battery by distinguishing it from the abnormality.

  The assembled battery of the present invention is particularly suitable for detecting abnormalities in a secondary battery that repeats charging and discharging represented by lithium ions and the like.

  The invention according to claim 6 is the invention according to any one of claims 1 to 5, wherein the control unit includes a first threshold value determination unit and a second threshold value determination unit. Is.

  In addition, the invention according to claim 7 is the invention according to claim 6, wherein the control unit is configured to each of the battery cells or each of the battery cells based on the determination results of the first threshold value determination unit and the second threshold value determination unit. An abnormality detection unit that detects an abnormality of the current sensor is provided.

  The invention according to claim 8 is the invention according to any one of claims 1 to 7, wherein the magnetic detector can detect a magnetic flux density generated so as to surround a current path of each battery cell. It is characterized by being.

  In a current sensor using a magnetic detection unit, the periphery of a normal current path is surrounded by a magnetic core, and the magnetic detection unit is disposed in the magnetic core. However, when the above-described current sensor is used, the assembled battery inevitably increases in size because it includes the magnetic core. Miniaturization is required for portable devices and the like, and it is natural that miniaturization is also required for assembled batteries. Therefore, a small current sensor capable of detecting current without using a magnetic core is preferable.

  The above example is a case of a general current sensor in which the magnetic core is formed of ferrite. Even if the magnetic core is formed of a thin plate such as permalloy, it is possible to achieve miniaturization. Therefore, the above-described small current sensor can be suitably used.

The invention according to claim 9 is the invention according to any one of claims 1 to 8, wherein the first current sensor outputs an output proportional to the magnetic flux density detected by the magnetic detection unit to the outside. It is characterized by this.

  By adopting this configuration, the current sensor can output an output proportional to the current value flowing through each battery cell, and if the output of the voltage value monitor is used together, the value of the internal impedance of each battery cell can also be detected.

The invention according to claim 10 is the invention according to any one of claims 1 to 9, wherein the first current sensor includes a plurality of the magnetic detection units.

  The current sensor includes a plurality of magnetic detection units, and by synchronizing the sampling processing of these output signals, the current values of the current paths at the same time can be compared.

  In addition, by making the plurality of magnetic detection parts go through the same history in the manufacturing process, each current sensor can be made to have similar characteristics. In order to measure the current of each battery cell in the assembled battery in which m battery cells are arranged in parallel, the current sensor including the m magnetic detectors as described above is used to accurately measure each current value. Can be detected.

According to an eleventh aspect of the present invention, in the invention according to any one of the first to tenth aspects, the first current sensor has an output difference between the plurality of magnetic detection units exceeding a first threshold value. In this case, the output is output to the outside.

  In the assembled battery of the present invention, when detecting the current flowing through the battery cells in the parallel relationship, the current value flowing through each battery cell is not output, but each current value (or internal impedance of the cell) An imbalance is detected and an alarm is output when a certain threshold is exceeded.

  For example, an application such as outputting an alarm when the internal impedance value of each battery cell deviates by 15% and prompting to stop using the battery can be considered. This value is not limited to 15%. For example, a value from about 10% to about 40% can be selected as appropriate, and an alarm to be issued in each state can be changed.

  According to a twelfth aspect of the present invention, in the invention according to any one of the first to eleventh aspects, the magnetic detection unit is a magnetic detection unit using a Hall effect.

  By using a magnetic detection unit utilizing the Hall effect, the output of the current sensor is proportional to the detected magnetic flux density, which is particularly suitable for applications in which the amount of current and internal impedance are detected.

  According to a thirteenth aspect of the present invention, in the twelfth aspect of the present invention, the magnetic detection unit using the Hall effect has a III-V group compound semiconductor such as InSb, InAs, or GaAs. It is characterized by.

  Since the S / N of the Hall sensor is improved by using the III-V group compound semiconductor, it is suitable when a high-resolution current sensor is required. In applications that do not require so much resolution, it is not essential to use III-V group compound semiconductors, and Si group IV semiconductors can also be used.

The invention according to claim 14 is the invention according to any one of claims 1 to 11, wherein the magnetic detection unit is a magnetic detection unit using a magnetoresistive effect. .

The invention according to claim 15 is the invention according to any one of claims 1 to 14, wherein the first current sensor has a magnetic material.

  For example, by including a piece of magnetic material inside the magnetic sensor, the direction of the magnetic field detected by the magnetic sensor can be rotated by 90 degrees. By adopting such a configuration, it is possible to provide a current sensor that is small and has a high degree of freedom in arrangement. In addition, the magnetic flux density of the magnetic material can be used to amplify the detected magnetic flux density to about 3 to 4 times, and a small current sensor that does not use the magnetic material core can be provided.

  The invention described in claim 16 is characterized in that, in the invention described in claim 15, the coercive force of the magnetic material is 30 A / m or less.

  When the current sensor has a magnetic material, the residual magnetic flux density of this material may adversely affect the current detection accuracy. In order to reduce this influence, it is preferable to select a magnetic material having a small coercive force. For example, when a NiFe (permalloy) material whose coercive force is suppressed to 30 A / m by adding boron is used, in the embodiment described later, the detected current error due to the hysteresis component of the magnetic material is a current of 1 A. Can be suppressed to about 40 mA. In another embodiment, when the sensitivity of the magnetic detection unit is changed, the value of the coercive force can be appropriately changed to about 150 A / m.

The invention according to claim 17 is the invention according to any one of claims 1 to 16, wherein the first current sensor is provided with a magnetic shield.

  In general, the electrodes and covers of battery cells are generally made of a material using a magnetic material. Since the residual magnetic flux density of this material may adversely affect the current detection of the battery cell, a magnetic shield can be provided around the magnetic detection unit so as to eliminate the influence.

  In addition, in personal computers, since the discharge from the battery changes at short time intervals, the steady magnetic flux density (residual magnetic flux density of the structure) is ignored, and the magnetic flux density that changes over time (battery cell) It is effective to detect only the component proportional to the current. A magnetic shield such as a high pass filter is preferred.

  Needless to say, an arithmetic processing (algorithm) that can ignore the influence of the steady residual magnetic flux density is effective.

The invention according to claim 18 is characterized in that, in the invention according to any one of claims 1 to 17, the magnetic detection unit is located 200 μm or less from the side surface of the casing of the first current sensor. It is what.

  When the magnetic core is not used, the magnetic flux density generated so as to surround the current path becomes smaller in inverse proportion to the distance from the current path. For this reason, in order to improve current detection accuracy, a structure in which the magnetic detection unit can be disposed close to the current path is preferable. By adopting a structure in which the thickness of the resin layer on the magnetic detection unit in the current sensor casing is thin, the magnetic detection unit can be brought closer to the current path in the configuration in which the resin layer surface is disposed immediately above the current path.

  In order to bring the magnetic detection unit closer to the current path to be measured, it is preferable to provide the magnetic detection unit on the mounting surface side of the current sensor housing.

  According to a nineteenth aspect of the present invention, in an electronic device that is driven by an assembled battery in which a plurality of battery cells are used and the battery cells are combined and connected in series and in parallel, the assembled battery includes the first to eighteenth aspects. The assembled battery according to any one of the above.

  By driving the electronic device using the above-described assembled battery, it is possible to accurately control charging / discharging and to detect abnormality of the battery cell, and to provide an electronic device with excellent safety.

  According to the assembled battery and the electronic apparatus using the same according to the present invention, the battery pack includes a first current sensor for detecting a current flowing through each battery cell, and the first current sensor includes a magnetic detection unit, a magnetic sensor, and a magnetic sensor. A sampling processing unit that samples the output signal of the detection unit, a trigger detection unit that detects an external trigger signal, and a hold processing unit that holds the output signal of the magnetic detection unit, and is synchronized with the external trigger signal The magnetic detection unit and the sampling processing unit are driven, and the output signal of the magnetic detection unit sampled by the sampling processing unit is held by the hold processing unit. Provided is a magnetic current sensor that can constitute a battery and is suitable for current detection of a plurality of battery cells constituting an assembled battery and capable of detecting a plurality of currents to be measured at the same time. Provided is an assembled battery or an electronic device equipped with an abnormality detection control unit capable of accurately detecting when an abnormality occurs in any of the battery cells constituting the assembled battery, capable of accurate charge / discharge management. be able to.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 2 is a block diagram for explaining an embodiment of the magnetic sensor according to the present invention. The current sensor 9 includes a plurality of magnetic detection units 11a to 11c, sampling processing units 12a to 12c, and a trigger detection unit. 13 and hold processing units 14a to 14c. The number of magnetic detection units in the present embodiment is three, but can be changed as appropriate according to the application. In addition, it is not necessary to include three current sensors in an integrated housing, and it is naturally possible to install three current sensors in separate housings due to restrictions on the location of the current sensors.

  Detection signals from the plurality of magnetic detection units 11a to 11c are configured to be sampled by the sampling processing units 12a to 12c, respectively.

  The signals sampled by the sampling processing units 12a to 12c are input to the hold processing units 14a to 14c, respectively, and are held until the next signal is input and appropriately output to the outside. ing.

  The sampling processing units 12a to 12c are driven in synchronization with an external trigger signal input to the trigger detection unit 13, and are configured to perform sampling only once. Further, the drive circuits of the magnetic detection units 11 a to 11 c can also be driven in synchronization with the external trigger signal input to the trigger detection unit 13.

  FIG. 3 is a block diagram for explaining an embodiment in the case where a plurality of current sensors shown in FIG. 2 are used, and includes current sensors 9 a and 9 b and a control unit 15. This block diagram is a configuration suitable for battery cell abnormality detection. When performing current detection, the control unit 15 is configured to input a common trigger signal to the current sensors 9a and 9b and appropriately capture the detection signals of the current sensors 9a and 9b. The control unit 15 includes a first threshold determination unit 15a, a second threshold determination unit 15b, a battery cell abnormality detection unit 15c, and a current sensor abnormality detection unit 15d.

  In this embodiment, a block configuration using two current sensors having three magnetic detection units is described, but the scope of application of the present invention is not limited to such a configuration.

  FIG. 12 is a more detailed block diagram of an embodiment of the current sensor according to the present invention. The current sensor 9 includes a magnetic detection unit 11, an offset cancellation circuit 24, a signal amplification circuit 25, an A / D conversion circuit / register circuit 26, and a switch 27.

  The detection signal from the magnetic detection unit 11 is sampled by the offset cancel circuit 24, and at the same time, the offset component included in the detection signal is removed. The sampled signal is amplified by the signal amplification circuit 25 so as to obtain a predetermined A / D conversion resolution, converted to a digital value by the A / D conversion circuit and the register circuit 26, and then stored in the register. .

  These series of signal processing circuits are driven by the power supply voltage Vdd input between the power supply terminal 28a and the ground terminal 28b. However, the power supply voltage Vdd is applied to the signal processing circuit only when the switch 27 is turned on. The switch 27 is turned on by a trigger signal MEG_TRG input from the trigger terminal 28c.

  The value stored in the register can be output by the I2C serial communication method using the serial clock terminal 28d and the serial data terminal 28e.

  In FIG. 12, only one magnetic detection unit is provided, but it goes without saying that the same configuration is possible even if a plurality of magnetic detection units are provided.

  FIG. 13 is a simple timing chart showing the operation of the current sensor block shown in FIG. Note that MEG_TRG in the figure indicates the voltage waveform of the signal MEG_TRG shown in FIG. While the external trigger signal MEG_TRG is not input, the circuit is in a sleep state and is configured to suppress power consumption. When MEG_TRG is input, sampling is started in synchronization with the rise of MEG_TRG. After the offset cancellation and sampling are finished, the output is latched and the circuit automatically returns to the sleep state.

  FIG. 4 is a circuit configuration diagram of the assembled battery according to the present invention. This assembled battery includes two battery blocks 10a and 10b connected in series with each other, a charge / discharge changeover switch 6 connected to the battery block, and a shunt resistor as a current sensor connected to the charge / discharge changeover switch 6. 5. Of course, the shunt resistor 5 can be omitted.

  The battery block 10a includes a plurality of battery cells 1a to 1c connected in parallel to each other, and a current sensor comprising the block configuration shown in FIG. 1 provided for detecting the current flowing through the battery cells 1a to 1c. 9a, a discharge circuit 3a connected in parallel to the group of the battery cells 1a to 1c and the current sensor 9a, and a switch 4a. Moreover, the magnetic sensor 9a has the magnetic detection parts 7a-7c, and the magnetic detection parts 7a-7c are arrange | positioned so that the electric current of battery cell 1a-1c may be detected, respectively.

  The battery block 10a includes a plurality of battery cells 2a to 2c connected in parallel to each other, and the block configuration shown in FIG. 1 provided for detecting the current flowing through the battery cells 2a to 2c. It comprises a current sensor 9b, a discharge circuit 3b connected in parallel to the group of these battery cells 2a to 2c and the current sensor 9b, and a switch 4b. Moreover, the current sensor 9b has magnetic detection units 8a to 8c, and the magnetic detection units 8a to 8c are arranged so as to detect currents of the battery cells 2a to 2c, respectively.

  The trigger signals of the current sensors 9a and 9b are output from the control unit 15, and the detection signals from the current sensors 9a and 9b are input to the control unit 15 (not shown). This output signal may be an analog value or a digital value.

  Further, as described above, the discharge circuits 3a and 3b are disposed in the battery blocks 10a and 10b, and are used by using the switches 4a and 4b when necessary. Further, a single current sensor (shunt resistor) 5 is disposed at a location where all current flows. This can be substituted by the current sensor 9a or 9b. Further, the current traveling direction is appropriately and safely switched using the charge / discharge switch 6 that performs switching at the time of charging and discharging.

  In addition, a voltage detection unit (Vmid) for detecting the temperature of the assembled battery and the voltage of the battery cell is provided, and an output signal thereof is configured to be input to the control unit 15. Moreover, the control part 15 is comprised so that the charging / discharging management of an assembled battery and the abnormality detection of each battery cell may be performed according to the detection result of a temperature, a voltage detection part, and a current sensor.

  FIG. 5 is a conceptual diagram for explaining the operation of the battery pack according to the present invention. The assembled battery abnormality detection operation by the control unit 15 in the configuration shown in FIGS. 3 and 4 will be described below. For simplicity of explanation, the peripheral circuit portion is omitted and only the battery cell portion is described.

  In FIG. 5, the combination of the battery cells 1a to 1c and 2a to 2c and the magnetic detection units 7a to 7c and 8a to 8c will be described as an example. It is assumed that the current values detected by the magnetic detection units 7a to 7c and 8a to 8c are I1 to I6, respectively.

  The first threshold value determination unit 15a compares the current values I1 to I6 detected by the magnetic detection units 7a to 7c and 8a to 8c with a predetermined threshold value TH1, for example, | I1-I2 |> TH1 and | I3 In the case of −I1 |> TH1, it is determined that the battery abnormality of the battery cell 1a that exists in common in both systems or the abnormality of the magnetic detection unit 7a.

  In addition, for example, when | (I1 + I2 + I3) − (I4 + I5 + I6) |> TH2, one of the magnetic detection units 7a to 7c and 8a to 8c is abnormal, and | (I1 + I2 + I3) When-(I4 + I5 + I6) |> TH2 is not satisfied, it is determined that any of the battery cells 1a to 1c and 2a to 2c is abnormal.

  The determination results of the first threshold determination unit 15a and the second threshold determination unit 15b are detected by the battery cell abnormality detection unit 15c and the current sensor abnormality detection unit 15d, respectively, based on, for example, the predetermined process as described above. .

  FIG. 6 is a flowchart for explaining a predetermined process for detecting an abnormality of the assembled battery according to the present invention. First, the detection currents I1 to I6 of the magnetic detection units 7a to 7c and 8a to 8c are read (step S1). Next, is the absolute value of (I1-I2), (I2-I3), (I3-I1), (I4-I5), (I5-I6), (I6-I4) greater than a predetermined threshold value TH1? It is determined whether or not (steps S2 to S7). When normal, I1, I2, and I3, and I4, I5, and I6 are values that do not change so much, and any absolute value is smaller than TH1. When │I1-I2│> TH1 and │I3-I1│> TH1, it is found that the battery abnormality of the battery cell 1a existing in both formulas is abnormal or the abnormality of the magnetic detection unit 7a. (Step S21).

  Similarly, when │I1-I2│> TH1 and │I2-I3│> TH1, it is a battery abnormality of the battery cell 1b that is common to both formulas or an abnormality of the magnetic detection unit 7b. (Step S31).

  Similarly, in the case of | I2-I3 |> TH1 and | I3-I1 |> TH1, it is a battery abnormality of the battery cell 1c that is common to both formulas or an abnormality of the magnetic detection unit 7c. (Step S41).

  Similarly, in the case of | I4-I5 |> TH1 and | I6-I4 |> TH1, it is a battery abnormality of the battery cell 2a that is common to both equations or an abnormality of the magnetic detection unit 8a. (Step S51).

  Similarly, in the case of | I4-I5 |> TH1 and | I5-I6 |> TH1, it is a battery abnormality of the battery cell 2b that is common to both formulas or an abnormality of the magnetic detection unit 8b. (Step S61).

  Similarly, in the case of | I5-I6 |> TH1 and | I6-I4 |> TH1, it is a battery abnormality of the battery cell 2c that is common to both formulas or an abnormality of the magnetic detection unit 8c. (Step S71).

  Next, it is determined whether or not the absolute value of the difference between (I1 + I2 + I3) and (I4 + I5 + I6) is greater than a predetermined threshold value TH2 (step S9). If the magnetic sensor output is calibrated, TH2 becomes zero. (I1 + I2 + I3) and (I4 + I5 + I6) should be the same value. When | (I1 + I2 + I3) − (I4 + I5 + I6) |> TH2, any of the magnetic detection units 7a to 7c and 8a to 8c is abnormal (step) S10). In this case, a part replacement recommendation or the like is performed (step S11).

  If | (I1 + I2 + I3) − (I4 + I5 + I6) |> TH2, any of the battery cells 1a to 1c and 2a to 2c is abnormal (step S12). In this case, a countermeasure such as stoppage of use is recommended (step S13).

  By performing such a predetermined process, as in the case described above, any of the battery cells 1a to 1c and 2a to 2c is abnormal, or any of the magnetic detection units 7a to 7c and 8a to 8c is It is possible to determine whether it is abnormal.

  From the above predetermined processing, | I1-I2 | ≦ TH1, | I2-I3 | ≦ TH1, | I3-I1 | ≦ TH1, | I4-I5 | ≦ TH1, | I5-I6 | ≦ TH1, | I6- When I4 | ≦ TH1 and | (I1 + I2 + I3) − (I4 + I5 + I6) | ≦ TH2, it can be determined that the assembled battery is normal.

  Note that there are cases where determination can be made without performing determination for all of these combinations, and it is also possible to determine abnormality by examining the current values I1 to I6 themselves. For example, if it is known from the specification of the battery cell that the probability of occurrence of abnormality such as ignition increases when a current of a certain value or more flows, it may be determined whether or not the value is less than that value.

  The predetermined processing described above can be performed at certain timings while the assembled battery is incorporated in an electronic device and the electronic device is being used. The same verification can be performed not only at the time of discharging but also at the time of charging the assembled battery.

  It is also possible to use a transient current change waveform in which the current value suddenly increases or decreases when charging / discharging starts. For example, by measuring the rise time of the current, the internal impedance of the battery cell can be calculated, and abnormality detection can be performed using this.

  Further, since the assembled battery is generally provided with a current sensor for detecting the current flowing through the entire assembled battery, such as the shunt resistor 5, for example, in this embodiment, one of the battery cells connected in parallel is provided. The current value can be obtained by calculation without providing a current sensor. Therefore, for example, the magnetic detection units 7c and 8c can be omitted.

  FIG. 14 is a block diagram for explaining an embodiment in which a plurality of current sensors shown in FIG. 2 are used, and includes current sensors 9a and 9b and a control unit 15 according to the present invention. This block diagram is a configuration suitable for charge / discharge management of battery cells. When performing current detection, the control unit 15 is configured to input a common trigger signal to the current sensors 9a and 9b and appropriately capture the detection signals of the current sensors 9a and 9b. Moreover, the control part 15 is provided with the calculation part 15e, the battery remaining charge memory | storage part 15f, and the time measurement part 15g.

  In this embodiment, a block configuration using two current sensors having three magnetic detection units is described, but the scope of application of the present invention is not limited to such a configuration.

  FIG. 15 is a flowchart for explaining the charge / discharge management method according to the present invention. First, the detection currents I1 to I6 of the magnetic detection units 7a to 7c and 8a to 8c are read (step S101). Whether the battery is charged or discharged is determined based on the directions of the detection currents I1 to I6 (step S102).

  When the battery is in the discharged state, the charges Q1 'to Q6' discharged from the respective battery cells are calculated using the detected currents I1 to I6 and the discharge time measured by the time measuring unit 15g. By subtracting this value from the previously recorded battery level, the current battery level is set to Q1 to Q6 (step 103). If any of the remaining battery levels is smaller than the predetermined threshold value Qmin, it is determined that the remaining battery level is zero and an alert is issued (step 105).

  When the battery is in a charged state, whether the voltage of each battery cell | (V +) − (Vmid) | or | (Vmid) − (V−) | is compared with a predetermined threshold value Vmax, and charging is performed at a constant voltage Whether to charge with a constant current is determined (step S107).

  When | (V +) − (Vmid) | <Vmax and | (Vmid) − (V−) | <Vmax, charging is performed at a constant current. In this case, feedback control is performed so that charging is performed with a predetermined current using the values of I1 to I6 (step S108).

  When | (V +) − (Vmid) |> Vmax or | (Vmid) − (V−) |> Vmax, charging is performed at a constant voltage. In this case, it is determined whether any of the values of the detection currents I1 to I6 is equal to or less than a predetermined threshold value Imin (step S109). If this is equal to or less than Imin, the battery cell is fully charged and charged. The process ends (step S110).

  When the charging is not completed, charges Q1 ′ to Q6 ′ charged in the respective battery cells are calculated using the detected currents I1 to I6 and the discharge time measured by the time measuring unit 15g. By adding this value to the previously recorded remaining battery level, the current remaining battery levels Q1 to Q6 are set (step 111).

  This is an example showing a flow of one cycle of charge / discharge management of the assembled battery, and by repeating this cycle a plurality of times, for example, an object such as completion of charging can be achieved.

  By making the determination as described above, even if the internal impedance of each battery cell is different and the current value flowing through each battery cell is different, any battery cell is not overcharged, overdischarged, Accurate charge / discharge management can be performed.

  Note that the charge / discharge management method is not limited to the above method, and it is needless to say that more accurate charge / discharge management is possible by using other parameters such as battery temperature.

  Further, since the assembled battery is generally provided with a current sensor for detecting the current flowing through the entire assembled battery, such as the shunt resistor 5, for example, in this embodiment, one of the battery cells connected in parallel is provided. The current value can be obtained by calculation without providing a current sensor. Therefore, for example, the magnetic detection units 7c and 8c can be omitted.

  FIG. 7 is a view showing a mounting portion of the magnetic sensor according to the present invention. When a current flows through a plurality of current paths provided on a printed board or a flexible board, a magnetic flux density is generated so as to surround each current. The current sensor is arranged at a position where each magnetic detection unit in the current sensor can individually detect this. In this embodiment, the current sensor is disposed so as to straddle the current path. The current sensor has a magnetic body inside, and can detect a magnetic flux density parallel to the substrate surface and perpendicular to the direction of current travel, as will be described later.

  In a current sensor using a magnetic detection unit, a type in which a closed magnetic path is formed by enclosing a current path with a magnetic material is generally used. However, the example shown in FIG. 7 without a closed magnetic path is small, and is built in a battery pack. Cheap. In the example shown in FIG. 7, the magnetic field traveling direction is converted by the magnetic substance inside the current sensor, but at the same time, the magnetic field generated from the current can be amplified, and can be used suitably for weak current detection. It is.

  Furthermore, a magnetic shield may be provided in order to ensure a constant current detection accuracy even in a large disturbance magnetic field. When a magnetic shield is provided, a disturbance magnetic field can be reduced by surrounding the entire measurement system including a current path and a current sensor with a magnetic material, for example.

  FIG. 8 is a sectional view schematically showing the structure of the current sensor according to the present invention. In order to simplify the description, some of the processing ICs are omitted, and only the magnetic detection unit is shown.

  In FIG. 8, magnetic detection units 11a to 11c are arranged on the semiconductor substrates 20a to 20c arranged on the lead frame 17, respectively, and the thickness is 15 μm or less on the magnetic detection units 11a to 11c. Magnetic bodies 21a to 21c are arranged. Here, the magnetic bodies 21a to 21c are arranged to change the traveling direction of the magnetic flux in a direction perpendicular to the magnetic detection units 11a to 11c when a magnetic flux parallel to the magnetic detection units 11a to 11c is generated.

  On the semiconductor substrates 20 a to 20 c, electrodes (not shown) that are electrically connected to the magnetic detection unit are formed, and are electrically connected to the lead frame 17 and the bonding wires 19. The components of these current sensors are sealed with the mold resin 18 so that the resin layer thickness on the surfaces of the magnetic detection units 11a to 11c is d, and corrode due to chemical reaction with humidity and corrosive gas. In addition, the sensor is protected from destruction of the sensor due to mechanical shock.

  The lead frame 17 is shaped so that the magnetic detection units 11 a to 11 c face the mounting substrate 23. In the optimum embodiment, the central axes of the plurality of current paths 22a to 22c provided on the mounting substrate 23 are arranged directly below the magnetic detection units 11a to 11c, respectively.

  FIG. 11 is a diagram showing details of the arrangement around the magnetic body and the lines of magnetic force in the mounting example of FIG. When a magnetic flux parallel to the substrate surface and perpendicular to the current traveling direction is applied to the magnetic detection unit, the magnetic flux traveling direction changes in the direction perpendicular to the substrate surface near the edge of the magnetic body 21 as shown in FIG. For this reason, by arranging the magnetic detection unit 11 on the edge of the magnetic body 21, a vertical component of the magnetic flux is generated on the magnetic detection unit 11. This arrangement is particularly suitable for a Hall element that detects a magnetic flux penetrating the magnetosensitive surface vertically.

  FIG. 9 is a diagram for explaining the relationship between the thickness d of the resin layer on the magnetic detection unit and the magnetic flux density generated in the magnetic detection units 22a to 22c from the current paths 11a to 11c in FIGS. Fig. 5 shows the calculation of the magnetic flux density generated in the magnetic detection part while changing the thickness d of the resin layer for a current path (maximum current 2A) on a general wiring board having a cross-sectional shape of 2 mm x t35 µm. It is. It can be seen that there are a plurality of combinations (11a and 22a, 11b and 22b, and 11c and 22c) of the magnetic detection unit and the current path, and the output of the magnetic sensor changes depending on the thickness of the wiring layer.

  From the calculation result shown in FIG. 9, it can be seen that if the thickness d of the resin layer on the magnetic detection unit is reduced, the magnetic flux density generated in the magnetic detection unit from the current path is increased.

  In an assembled battery using a plurality of lithium ion battery cells used in a notebook personal computer or the like, it is said that an accuracy of 50 mA or more is required to detect abnormality of each battery cell by current detection. When a Hall element using InSb having an excellent S / N ratio is applied as the magnetic detection section, and the arrangement of the magnetic material is optimized, the S / N ratio of the Hall element using InSb is taken into consideration, and the current is 50 mA or more In order to ensure the accuracy, a generated magnetic flux density of 0.27 mT per 1A is required. Therefore, it can be seen that the thickness d of the resin layer on the magnetic detection portion needs to be 200 μm or less.

  In the above-described embodiment, a substrate having a plurality of current paths arranged in one direction is assumed and an optimal magnetic sensor configuration is shown. However, the scope of application of the present invention is limited to such a configuration. is not. For example, in order to reduce the influence of the magnetic flux density generated from the current path other than the current to be measured, it goes without saying that the same effect can be obtained for the current paths in which the respective current paths are orthogonal.

  FIG. 10 is a diagram showing detection accuracy when performing current detection of a battery cell in the best embodiment of the present invention, and when charging / discharging the battery cell with a load of 0.75 C using a charge / discharge tester. Is measured using a shunt resistance and the magnetic sensor of the present invention. This measurement result relates to the current of one battery cell constituting the assembled battery.

  From the measurement results shown in FIG. 10, it can be seen that the current value detected by the magnetic sensor closely follows the current value detected by the shunt resistor.

It is a circuit block diagram which shows schematic structure of the conventional assembled battery. It is a block block diagram for demonstrating one Example of the current sensor which concerns on this invention. It is a block block diagram for demonstrating one Example in the case of using two or more current sensors shown in FIG. It is a circuit block diagram of the assembled battery which concerns on this invention. It is a conceptual diagram for demonstrating operation | movement of the assembled battery which concerns on this invention. It is a figure which shows the flowchart for demonstrating the predetermined process which detects the abnormality of the assembled battery which concerns on this invention. It is the figure which showed the mounting part of the current sensor which concerns on this invention. It is sectional drawing which showed roughly the structure of the current sensor which concerns on this invention. 5 and 6 are diagrams for explaining the relationship between the thickness of the resin layer on the magnetic detection unit and the magnetic flux density generated in the magnetic detection unit from the current path. It is a figure which shows the detection accuracy at the time of performing the current detection of a battery cell in the best embodiment of this invention. It is the figure which showed the detail of arrangement | positioning around a magnetic body in FIG. 8, and a magnetic force line. It is a more detailed block block diagram of one Example of the current sensor which concerns on this invention. It is a timing chart of the current sensor block shown in FIG. It is a block block diagram for demonstrating one Example in the case of using two or more magnetic sensors shown in FIG. It is a figure which shows the flowchart for demonstrating the predetermined process which detects the abnormality of the assembled battery which concerns on this invention.

Explanation of symbols

1a to 1c, 2a to 2c Battery cells 3a and 3b Discharge circuits 4a and 4b Switch 5 Shunt resistor 6 Charge / discharge switches 7a to 7c, 8a to 8c Magnetic detectors 9, 9a, 9b Current sensors 10a, 10b Battery blocks 11, 11a -11c Magnetic detection unit 12a-12c Sampling processing unit 13 Trigger detection unit 14 Hold processing unit 15 Control unit 15a First threshold value determination unit 15b Second threshold value determination unit 15c Battery cell abnormality detection unit 15d Current sensor abnormality detection unit 17 Lead frame 18 Resin 19 Bonding wire 20 Semiconductor substrates 21, 21a to 21c Magnetic bodies 22, 22a to 22c Current path 23 Mounting substrate 24 Offset cancel circuit 25 Signal amplification circuit 26 A / D conversion circuit and register circuit 27 Switches 28a to e External terminals (28a Power supply terminal, 28b Ground terminal, 28 c Trigger terminal, 28d Serial clock terminal, 28e Serial data terminal)

Claims (19)

In an assembled battery in which a plurality of battery cells are used and the battery cells are connected in combination in series and in parallel,
A first current sensor for detecting a current flowing through each battery cell;
The first current sensor includes a magnetic detection unit;
A sampling processing unit for sampling the output signal of the magnetic detection unit;
A trigger detector for detecting an external trigger signal;
A hold processing unit that holds an output signal of the magnetic detection unit;
The assembled battery, wherein the magnetic detection unit and the sampling processing unit are driven in synchronization with the external trigger signal, and an output signal of the magnetic detection unit sampled by the sampling processing unit is held by a hold processing unit . In a battery pack in which m battery cells are connected in parallel and n battery blocks are connected in series (m and n are positive integers),
A second current sensor for detecting an entire current value of the assembled battery;
A first current sensor for detecting a current flowing through any (m−1) battery cells in each battery block;
The first current sensor includes a magnetic detection unit;
A sampling processing unit for sampling the output signal of the magnetic detection unit;
A trigger detector for detecting an external trigger signal;
A hold processing unit that holds an output signal of the magnetic detection unit;
The assembled battery, wherein the magnetic detection unit and the sampling processing unit are driven in synchronization with the external trigger signal, and an output signal of the magnetic detection unit sampled by the sampling processing unit is held by a hold processing unit .   The assembled battery according to claim 1 or 2, wherein each of the first current sensors is disposed in the vicinity of a current path of each battery cell.   The assembled battery according to claim 1, further comprising a charge / discharge management control unit that performs charge / discharge management of the assembled battery using an output value of each of the first current sensors.   An abnormality detection control unit that detects that an abnormality has occurred in any of the battery cells of the assembled battery by a predetermined process according to a connection form of the assembled battery from an output value of each first current sensor. The assembled battery according to any one of claims 1 to 4, wherein   The assembled battery according to claim 5, wherein the abnormality detection control unit includes a first threshold determination unit and a second threshold determination unit.   The abnormality detection control unit includes an abnormality detection unit that detects an abnormality of each battery cell or each current sensor based on determination results of the first threshold determination unit and the second threshold determination unit. The assembled battery according to claim 6.   The assembled battery according to claim 1, wherein the magnetic detection unit can detect a magnetic flux density generated so as to surround a current path of each battery cell. The assembled battery according to claim 1, wherein the first current sensor outputs an output proportional to a magnetic flux density detected by the magnetic detection unit to the outside. The assembled battery according to claim 1, wherein the first current sensor includes a plurality of the magnetic detection units. The group according to claim 1, wherein the first current sensor outputs an output to the outside when an output difference between the plurality of magnetic detection units exceeds a first threshold value. battery.   The assembled battery according to claim 1, wherein the magnetic detection unit is a magnetic detection unit using a Hall effect.   The assembled battery according to claim 12, wherein the magnetic detection unit using the Hall effect includes a III-V group compound semiconductor such as InSb, InAs, or GaAs.   The assembled battery according to claim 1, wherein the magnetic detection unit is a magnetic detection unit using a magnetoresistive effect. The assembled battery according to claim 1, wherein the first current sensor has a magnetic body.   The assembled battery according to claim 15, wherein a coercive force of the magnetic body is 30 A / m or less. The assembled battery according to any one of claims 1 to 16, wherein the first current sensor is provided with a magnetic shield. 18. The assembled battery according to claim 1, wherein the magnetic detection unit is located 200 μm or less from a side surface of the casing of the first current sensor. In an electronic device driven by an assembled battery in which a plurality of battery cells are used and the battery cells are connected in series and in parallel,
An electronic device, wherein the assembled battery is an assembled battery according to any one of claims 1 to 18.