JP2018125969A - Storage battery fuse judgment circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a fuse determination circuit capable of determining the state of a fuse provided in a storage battery. SOLUTION: A plurality of fuse control circuits 1 to n are provided between a power supply wiring PL and a plurality of storage batteries B1 to Bn, respectively. The fuse control circuits 1 to n include detection units 11 to 1n that output detection signals DET1 to DETn indicating the corresponding fuse state in response to the control signal CTL. The detection signals DET1 to DETn are input to the determination unit 41a via the multiplexer 42. According to the present invention, since the detection signals DET1 to DETn output from each of the detection units 11 to 1n are input to the determination unit 41a, it is possible to determine which fuse is blown. Moreover, since the plurality of detection signals DET1 to DETn are input to the determination unit 41a via the multiplexer 42, the number of signals supplied to the determination unit 41a can be significantly reduced. [Selection diagram] Fig. 2

Description

  The present invention relates to a fuse determination circuit, and more particularly to a fuse determination circuit that determines the state of a fuse provided in a storage battery.

  In recent years, a storage battery such as a lithium ion battery has been widely used as a power source used in electric vehicles, hybrid vehicles, and the like. Lithium ion batteries may include a fuse that is cut when an overcurrent or overvoltage occurs in order to prevent overcurrent or overvoltage ignition (see Patent Document 1).

JP 2006-109596 A

  However, when a plurality of lithium ion batteries are connected in parallel, this state cannot be recognized from the outside even if fuses assigned to some lithium ion batteries are cut. For this reason, not only will maintenance be hindered, but some lithium-ion batteries may be disconnected from the fuses, resulting in a decrease in the overall battery capacity. There is also a problem that a large error occurs in the remaining capacity.

  Therefore, an object of the present invention is to provide a fuse determination circuit capable of determining the state of a fuse provided in a storage battery.

  The fuse determination circuit according to the present invention is a fuse determination circuit for determining the states of a plurality of fuses respectively connected between a power supply wiring to which a charger or a load is connected and a plurality of storage batteries. A plurality of detection units connected to the storage battery or the power supply wiring and outputting a detection signal indicating the state of the fuse in response to a control signal; and the detection signals output from the plurality of detection units, respectively. A multiplexer; and a determination unit that determines states of the plurality of fuses based on an output of the multiplexer.

  According to the present invention, since the detection signal output from each detection unit is input to the determination unit, it is possible to determine which fuse is blown. In addition, since a plurality of detection signals are input to the determination unit via the multiplexer, the number of signals supplied to the determination unit can be greatly reduced.

  In the present invention, it is preferable that the control signal is commonly supplied to the plurality of detection units. According to this, the number of signal wirings required for the control signal can be minimized.

  In the present invention, the plurality of detection units are connected to the first transistor that is activated in response to the control signal when the fuse is in a connected state, and to the power supply wiring without passing through the fuse. And a second transistor controlled by the output of one transistor. According to this, since the first transistor is deactivated when the control signal is in an inactive state, it is possible to minimize power consumption by the fuse determination circuit.

  In the present invention, the plurality of fuses include first and second fuses connected in series between the storage battery and the power supply wiring, respectively, and the first transistor includes the first and second fuses. It is preferably connected between the connection point of the fuse and the ground, and is on / off controlled in response to the control signal. If such a three-terminal fuse circuit is used, the storage battery can be reliably disconnected when an abnormality occurs.

  In the present invention, it is preferable that each of the plurality of detection units includes a resistor that converts an on-current of the first transistor into a potential level of a control electrode of the second transistor. According to this, the state of the fuse can be determined with a simple circuit configuration.

  Preferably, the fuse determination circuit according to the present invention further includes a plurality of cutting circuits that are respectively assigned to the plurality of fuses and that cut the fuses in response to a fuse cutting signal. According to this, it becomes possible to cut the fuse when an abnormality occurs. In this case, the fuse cutting signals may be commonly supplied to the plurality of cutting circuits, or the individual fuse cutting signals may be supplied to the plurality of cutting circuits.

  Thus, according to the present invention, the state of the fuse provided in the storage battery can be determined by a simple circuit configuration.

FIG. 1 is a block diagram of a storage battery system including a fuse determination circuit according to a first embodiment of the present invention. FIG. 2 is a block diagram showing a configuration of the control circuit 40 used in the first embodiment. FIG. 3 is a circuit diagram of the fuse control circuits 1 to n according to the first embodiment. FIG. 4 is a block diagram of a storage battery system including a fuse determination circuit according to the second embodiment of the present invention. FIG. 5 is a block diagram showing a configuration of the control circuit 40 used in the second embodiment. FIG. 6 is a circuit diagram of the fuse control circuits 1 to n in the second embodiment.

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram of a storage battery system including a fuse determination circuit according to a first embodiment of the present invention.

  The storage battery system shown in FIG. 1 has a configuration in which n storage batteries B1 to Bn are connected in parallel. The storage batteries B1 to Bn are, for example, lithium ion batteries, and the battery capacity is increased by connecting them in parallel. Charging of the storage batteries B1 to Bn is performed by the charger 51. The charger 51 and the storage batteries B1 to Bn supply an operating voltage to a load 52 such as a motor via the power supply wiring PL.

  As shown in FIG. 1, the negative electrodes (−) of the storage batteries B1 to Bn are commonly connected to the ground wiring GND, and the positive electrodes (+) of the storage batteries B1 to Bn are connected to the power supply wiring PL via the three-terminal fuse circuits F1 to Fn, respectively. Connected in common. The voltage between the power supply line PL and the ground line GND, that is, the output voltage of the storage batteries B1 to Bn is monitored by the voltage monitoring unit 30.

  A three-terminal fuse circuit is a circuit consisting of two fuses connected in series and a resistance provided at the connection point, and not only blows itself by an overcurrent but also blows by heating using a heater resistor. Can do. A three-terminal fuse circuit F1 corresponding to the storage battery B1 is composed of fuses FA1, FB1 and a resistor R1, and a three-terminal fuse circuit F2 corresponding to the storage battery B2 is composed of fuses FA2, FB2 and a resistor R2, and is a three-terminal fuse corresponding to the storage battery Bn. The circuit Fn includes fuses FAn and FBn and a resistor Rn.

  The detection units 11 to 1n and the cutting units 21 to 2n are connected to the fuses assigned to the storage batteries B1 to Bn, respectively. Here, the three-terminal fuse circuit F1, the detection unit 11 and the cutting unit 21 constitute the fuse control circuit 1, and the three-terminal fuse circuit F2, the detection unit 12 and the cutting unit 22 constitute the fuse control circuit 2, and the three-terminal fuse. The circuit Fn, the detection unit 1n, and the cutting unit 2n constitute a fuse control circuit n.

  Each of the detection units 11 to 1n is a circuit that detects whether the corresponding fuse is in a connected state, that is, whether it is in a connected state or in a disconnected state (fused state). It becomes. Detection signals DET1 to DETn output from the detectors 11 to 1n are fed back to the control circuit 40. When there is no need to distinguish between them, the detection signals DET1 to DETn may be simply referred to as detection signals DET.

  The cutting units 21 to 2n are circuits for cutting the corresponding fuses, and are activated by a fuse cutting signal FC supplied from the control circuit 40. In the present embodiment, the fuse cutting signal FC is commonly input to the cutting units 21 to 2n. Therefore, when the fuse cutting signal FC is activated, all the fuses assigned to the storage batteries B1 to Bn are cut. The For this reason, when some serious abnormality occurs in the storage battery system, the control circuit 40 can disconnect all the storage batteries B1 to Bn from the power supply wiring PL by activating the fuse cutting signal FC.

  The control circuit 40 is also connected to the voltage monitoring unit 30. The control circuit 40 is a circuit that performs fuse determination using the detection signal DET and controls and monitors the storage battery system. For example, the control circuit 40 calculates the total remaining capacity of the storage batteries B1 to Bn.

  FIG. 2 is a block diagram showing a configuration of the control circuit 40.

  As shown in FIG. 2, the control circuit 40 includes an MPU 41 and a multiplexer 42. The MPU 41 is a circuit that controls the entire storage battery system, and includes a determination unit 41a for performing fuse determination. The MPU 41 also generates a control signal CTL and a fuse cutting signal FC. Here, the function of the determination unit 41a may be realized by hardware, or part or all of it may be realized by software.

  The multiplexer 42 receives the detection signals DET1 to DETn, and outputs any of the detection signals DET1 to DETn selected based on the selection signal SEL1 to the MPU 41. The detection signals DET1 to DETn output from the multiplexer 42 at a time may be only one, or may be two or more. The MPU 41 sequentially selects the detection signals DET1 to DETn by switching the value of the selection signal SEL1, and thereby can capture all the detection signals DET1 to DETn. The detection signals DET1 to DETn captured by the MPU 41 are analyzed by the determination unit 41a, and thereby the state of each fuse can be determined.

  Thus, since the detection signals DET1 to DETn are not directly input to the MPU 41 but are input to the MPU 41 via the multiplexer 42, the number of detection signals DET1 to DETn is large (= n). However, it is not necessary to increase the number of input terminals of the MPU 41, and a general-purpose MPU can be used.

  FIG. 3 is a circuit diagram of the fuse control circuits 1 to n.

  As shown in FIG. 3, since the fuse control circuits 1 to n have the same circuit configuration, the circuit configuration of the fuse control circuit 1 will be described as a representative. The fuse control circuit 1 includes a three-terminal fuse circuit F1, a detection unit 11, and a cutting unit 21.

  As described above, the three-terminal fuse circuit F1 includes the fuses FA1 and FB1 connected in series between the power supply wiring PL and the storage battery B1, and the resistor R1 provided at the connection point between the fuses FA1 and FB1. The resistor R1 also serves as a heater that generates heat for fusing the fuses FA1 and FB1.

  The detection unit 11 includes a P-channel type MOS transistor TP and an N-channel type MOS transistor TN1. The source of the transistor TP is connected to the connection point of the fuses FA1 and FB1 through the resistor R1, the drain is connected to the ground wiring GND through the resistors R11 and R12, and the gate electrode is connected to its own source through the resistor R13. Has been. The anode of the diode D is also connected to the gate electrode of the transistor TP. A control signal CTL is supplied from the control circuit 40 to the cathode of the diode D. A resistor R14 is connected between the anode of the diode D and the ground wiring GND. This resistor R14 is a resistor for preventing floating and needs to be sufficiently higher than the resistor R13.

  With this configuration, when the control signal CTL is at a high level, almost no current flows through the resistor R13, so that the gate-source voltage of the transistor TP becomes almost zero, and the transistor TP is turned off. On the other hand, when the control signal CTL is activated to a low level, the on / off state of the transistor TP is determined according to the states of the fuses FA1 and FB1. That is, when the fuses FA1 and FB1 are in the connected state, a current flows through the resistor R13, so that the gate-source voltage of the transistor TP exceeds the threshold voltage, and the transistor TP is turned on. On the other hand, when the fuses FA1 and FB1 are in the cut state, almost no current flows through the resistor R13, so that the transistor TP is turned off.

  Thus, since the transistor TP is connected to the power supply wiring PL and the storage battery B1 via the fuses FA1 and FB1, when the control signal CTL is activated to a low level, the transistor TP is turned on / off according to the state of the fuses FA1 and FB1. The state will be decided.

  On the other hand, the drain of the N-channel MOS transistor TN1 is connected to the power supply wiring PL via the resistor R15 without passing through the fuses FA1 and FB1, the source is connected to the ground wiring GND, and the gate electrode is formed of the resistors R11 and R12. Connected to the connection point. The detection signal DET1 is output from the drain of the transistor TN1.

  With this configuration, when the transistor TP is turned on, the on-current flowing through the resistor R12 causes the gate-source voltage of the transistor TN1 to exceed the threshold voltage, and the transistor TN1 is turned on. That is, the resistor R12 serves to convert the on-current of the transistor TN1 into a gate-source voltage. When the transistor TN1 is turned on, the detection signal DET1 becomes the ground level (low level). On the other hand, when the transistor TP is in the off state, the gate-source voltage of the transistor TN1 becomes zero, and the transistor TN1 is in the off state. When the transistor TN1 is in an off state, the detection signal DET1 is at a high level.

  Since the other detection units 12 to 1n have the same circuit configuration, redundant description is omitted. The control signal CTL is common to the detection units 11 to 1n. For this reason, when the control signal CTL is activated to a low level, the detection units 11 to 1n are simultaneously activated, and the detection signals DET1 to DETn corresponding to the storage batteries B1 to Bn are generated simultaneously.

  The detection signals DET1 to DETn thus generated are supplied to the control circuit 40 shown in FIG. Then, the MPU 41 included in the control circuit 40 sequentially takes in the detection signals DET1 to DETn by controlling the multiplexer 42 using the selection signal SEL1. As a result, the state of each fuse can be determined by the determination unit 41a.

  The determination result by the determination part 41a is utilized for control of the storage battery system by MPU41. For example, if it is known that some fuses are blown, it can be seen that the overall battery capacity of the storage battery system has decreased. For example, this is based on the current voltage level supplied from the voltage monitoring unit 30. Corrections can be made to the remaining capacity calculation. As a result, it is possible to avoid a decrease in remaining capacity that is not intended by the user. In addition, information regarding the presence or absence of fuse cutting can be output to the outside via the control circuit 40, thereby improving maintainability.

  It is sufficient that the control signal CTL is activated periodically for a short time. During the period when the control signal CTL is inactive to the high level, all the transistors TP and TN1 are in the off state regardless of the state of the fuse, so that the power consumption by the detection units 11 to 1n does not occur. Therefore, according to the present embodiment, it is possible to determine the state of the fuse at an arbitrary timing while minimizing an increase in power consumption.

  On the other hand, the cutting unit 21 includes an N-channel MOS transistor TN2 connected between the resistor R1 and the ground wiring GND, and a resistor R16 connected between the gate electrode of the transistor TN2 and the ground wiring GND. The fuse cutting signal FC is supplied to the gate electrode of the transistor TN2. Note that the resistor R16 is a pull-down resistor for grounding the gate electrode of the transistor TN2 in a normal state, and has a sufficiently high resistance value. The transistor size of the transistor TN2 is designed to be at least larger than that of the transistor TP.

  Thereby, when the fuse cutting signal FC is deactivated to a low level, the transistor TN2 is in an off state, and no current flows through the resistor R1. On the other hand, when the fuse cutting signal FC is activated to a high level, the transistor TN2 is turned on, so that a large current flows through the fuses FA1 and FB1 via the resistor R1 and is blown. Therefore, the control circuit 40 can cut all the fuses by activating the fuse cutting signal FC to a high level.

<Second Embodiment>
FIG. 4 is a block diagram of a storage battery system including a fuse determination circuit according to the second embodiment of the present invention.

  As shown in FIG. 4, the fuse determination circuit according to the present embodiment is different from the fuse determination circuit according to the first embodiment in that the fuse cutting signal FC is individually assigned to each of the cutting units 21 to 2n. To do. Specifically, the fuse cutting signal FC is composed of n-bit fuse cutting signals FC1 to FCn, which are supplied to the cutting units 21 to 2n, respectively. Since other configurations are the same as those of the fuse determination circuit according to the first embodiment, the same elements are denoted by the same reference numerals, and redundant description is omitted.

  FIG. 5 is a block diagram showing a configuration of the control circuit 40 used in the present embodiment.

  As shown in FIG. 5, the control circuit 40 used in this embodiment is different from the control circuit 40 shown in FIG. 2 in that a demultiplexer 43 is added. The demultiplexer 43 is a circuit that receives the fuse cutting signal FC output from the MPU 41 and outputs this as one of the fuse cutting signals FC1 to FCn based on the selection signal SEL2. Thereby, the control circuit 40 can supply the fuse cutting signals FC1 to FCn to the arbitrary cutting units 21 to 2n. As described above, if the disconnection signals FC1 to FCn are distributed to the disconnecting units 21 to 2n using the demultiplexer 43, it is not necessary to increase the number of output terminals of the MPU 41, and a general-purpose MPU can be used.

  FIG. 6 is a circuit diagram of the fuse control circuits 1 to n in the present embodiment.

  As shown in FIG. 6, in the present embodiment, fuse cutting signals FC1 to FCn are individually supplied to the cutting units 21 to 2n, respectively. Thereby, the control circuit 40 can cut | disconnect arbitrary fuses using the cutting parts 21-2n. Therefore, when a serious abnormality occurs in a specific storage battery, the functions of other storage batteries in which no abnormality has occurred can be maintained by selectively cutting only the fuse corresponding to the storage battery.

  Also in the present embodiment, by activating the control signal CTL, the detection signals DET1 to DETn can be obtained from the detection units 11 to 1n, thereby detecting the state of each fuse.

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention. Needless to say, it is included in the range.

  For example, in the above embodiment, the case where the present invention is applied to a lithium ion battery has been described as an example. However, the object of the present invention is not limited to a lithium ion battery, and may be applied to other types of storage batteries. Is possible.

  In the above embodiment, the common control signal CTL is assigned to the detection units 11 to 1n. However, the control signal CTL may be assigned to each of the detection units 11 to 1n, or a plurality of detection units 11 may be assigned. ˜1n may be classified into several groups, and the control signal CTL may be individually assigned to each group. In this case, similarly to the second embodiment, if a demultiplexer is used, an increase in the number of output terminals of the MPU 41 can be minimized.

  Further, in the above embodiment, the transistor TN1 is connected to the power supply line PL. However, as long as an operation voltage can be obtained regardless of the state of the fuse, it is not essential to connect the transistor TN1 to the power supply line PL. You may connect to a storage battery.

  Furthermore, although the case where the three-terminal fuse circuit was used was described as an example in the above embodiment, the present invention is not limited to this as long as it can be disconnected between the storage battery and the charger.

1 to n fuse control circuit 11 to 1n detection unit 21 to 2n cutting unit 30 voltage monitoring unit 40 control circuit 41a determination unit 42 multiplexer 43 demultiplexer 51 charger 52 load B1-Bn storage battery D diode F1-Fn 3-terminal fuse circuit FA1 , FB1, FA2, FB2, FAn, FBn Fuse GND Ground wiring PL Power supply wiring R1-Rn, R11-R16 Resistors TN1, TN2 N-channel MOS transistor TP P-channel MOS transistor

Claims (9)

A fuse determination circuit for determining a state of a plurality of fuses respectively connected between a power supply wiring to which a charger or a load is connected and a plurality of storage batteries,
A plurality of detectors connected to the storage battery or the power supply wiring via the corresponding fuses, and outputting a detection signal indicating the state of the fuse in response to a control signal;
A multiplexer for receiving the detection signals respectively output from the plurality of detection units;
A fuse determination circuit comprising: a determination unit configured to determine a state of the plurality of fuses based on an output of the multiplexer;   The fuse determination circuit according to claim 1, wherein the control signal is commonly supplied to the plurality of detection units.   The plurality of detection units are connected to the power supply wiring without passing through the fuse, a first transistor that is activated in response to the control signal when the fuse is in a connected state, and the first transistor The fuse determination circuit according to claim 1, further comprising: a second transistor controlled by an output. The plurality of fuses include first and second fuses connected in series between the storage battery and the power supply wiring,
4. The fuse according to claim 3, wherein the first transistor is connected between a connection point of the first and second fuses and a ground, and is on / off controlled in response to the control signal. Judgment circuit.   5. The fuse determination circuit according to claim 3, wherein each of the plurality of detection units includes a resistor that converts an on-current of the first transistor into a potential level of a control electrode of the second transistor. 6. .   6. The fuse determination circuit according to claim 1, further comprising: a plurality of cutting circuits that are respectively assigned to the plurality of fuses and that cut the fuses in response to a fuse cutting signal. 7.   The fuse determination circuit according to claim 6, wherein the fuse cutting signal is commonly supplied to the plurality of cutting circuits.   The fuse determination circuit according to claim 7, wherein each of the plurality of cutting circuits is supplied with an individual fuse cutting signal.   The fuse determination circuit according to claim 8, further comprising a demultiplexer that distributes the fuse cutting signal to the plurality of cutting circuits based on a selection signal.

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