WO2011036867A1

WO2011036867A1 - Disconnection detecting circuit and battery power supply device

Info

Publication number: WO2011036867A1
Application number: PCT/JP2010/005712
Authority: WO
Inventors: 淳朝倉
Original assignee: パナソニック株式会社
Priority date: 2009-09-28
Filing date: 2010-09-21
Publication date: 2011-03-31

Abstract

Disclosed is a disconnection detecting circuit which is provided with: a first capacitor, which has one end thereof connected to a terminal of a first battery of the first battery and a second battery connected in series, with a first conductive path electrically connected with the terminal therebetween, and which has the other end thereof connected to a second conductive path electrically connected to the connecting points of the batteries; a first series circuit, which is a series circuit having a first resistor and a first switching element connected in series and is connected to the first capacitor in parallel; a second capacitor, which has one end thereof connected to the connecting point with the second conductive path therebetween, and has the other end thereof connected to a second battery terminal on the side opposite to the connecting point; a first voltage detecting unit that detects voltages of both the ends of the first capacitor; and a determining unit, which determines that the first and/or the second conductive path is disconnected when first conditions where a voltage detected by means of the first voltage detecting unit exceeds a previously set first threshold voltage in a state wherein the first switching element is turned off, and a voltage detected by means of the first voltage detecting means is lower than a previously set second threshold voltage in a state wherein the first switching element is turned on are met.

Description

Disconnection detection circuit and battery power supply device

The present invention relates to a disconnection detection circuit for detecting a disconnection of a voltage measurement conductive path for monitoring the voltages of a plurality of batteries connected in series, and a battery power supply apparatus using the disconnection detection circuit.

Conventionally, in an assembled battery in which a plurality of batteries are connected in series, a technique for detecting disconnection of a voltage measurement circuit that measures the voltage of each battery is known (for example, see Patent Document 1). The technology described in Patent Document 1 is a voltage measurement circuit using a flying capacitor circuit. For voltage measurement, a capacitor is charged by sequentially connecting each battery with a changeover switch, and the charging voltage of the capacitor is charged. By detecting this, the voltage of each battery is measured.

However, since one capacitor is used in common by multiple batteries while switching connections sequentially, if the wiring connected to a battery is disconnected, the charging voltage from the battery whose voltage is measured before that battery remains in the capacitor. Therefore, there is a problem that the remaining charging voltage is measured as the voltage of the battery.

Therefore, in the technique described in Patent Document 1, when the voltage measurement of each battery is finished, the capacitor is discharged and reset, so that when the wiring connected to a certain battery is disconnected, the capacitor remains reset. Since the battery is not charged, the disconnection of the wiring can be detected.

However, with the technique described in Patent Document 1, it is determined that the capacitor is disconnected unless the capacitor is charged. Therefore, even when the output voltage of a certain battery included in the assembled battery becomes close to zero due to, for example, internal short-circuiting or discharging, the capacitor is not charged, so it has been determined that it is disconnected. .

Japanese Patent Laid-Open No. 2003-84015

An object of the present invention is to provide a disconnection detection circuit for detecting disconnection of a voltage measurement conductive path for monitoring the voltage of a plurality of batteries connected in series. Even if it becomes a case, it is providing the disconnection detection circuit which can reduce a possibility of detecting a disconnection accidentally, and a battery power supply device using the same.

In the disconnection detection circuit according to one aspect of the present invention, one end of the first and second batteries connected in series is connected to a terminal on the opposite side to the second battery of the first battery via a first conductive path. A first capacitor connected to the connection point via a second conductive path connected to the terminal and having the other end connected to the connection point of the first and second batteries; a first resistor; a first switching element; A first series circuit connected in parallel with the first capacitor, one end connected to the connection point via the second conductive path, and the other end connected to the connection point in the second battery. A second capacitor connected to a terminal opposite to the first capacitor, a first voltage detection unit for detecting a voltage across the first capacitor, and the first voltage detection unit with the first switching element turned off. The detected voltage is preset. When a first condition is satisfied, which exceeds a threshold voltage and the voltage detected by the first voltage detector in a state where the first switching element is turned on does not satisfy a preset second threshold voltage And a determination unit that determines that at least one of the first and second conductive paths is disconnected.

In addition, the battery power supply device according to one aspect of the present invention preferably includes the above-described disconnection detection circuit and the first and second batteries.

It is a block diagram which shows an example of a structure of the battery power supply device using the disconnection detection circuit which concerns on one Embodiment of this invention. It is a flowchart which shows an example of operation | movement of the battery power supply device shown in FIG. It is a flowchart which shows an example of operation | movement of the battery power supply device shown in FIG. It is a flowchart which shows an example of operation | movement of the battery power supply device shown in FIG. It is explanatory drawing for demonstrating operation | movement of the battery power supply device shown in FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted. FIG. 1 is a block diagram showing an example of the configuration of a battery power supply device using a disconnection detection circuit according to an embodiment of the present invention.

A battery power supply device 1 shown in FIG. 1 includes a disconnection detection circuit 2, an assembled battery 3, and

connection terminals

11, 12, and 13. The assembled battery 3 is configured by, for example, batteries B1, B2, B3, B4, and B5 connected in series in the same polarity direction. Hereinafter, the batteries B1, B2, B3, B4, and B5 are collectively referred to as a battery B.

Batteries B1, B2, B3, B4, and B5 are secondary batteries such as Ni-MH batteries and Li-ion batteries, for example. Each of the batteries B1, B2, B3, B4, and B5 may be a single cell, or may be a battery block in which a plurality of cells are connected in series, parallel, or a combination of series and parallel. Moreover, the number of the batteries B should just be plural, and is not restricted to five.

Connection terminals

11, 12, and 13 are connection terminals for connecting to external devices (not shown). The external device is, for example, a charging device that charges the assembled battery 3 or a load circuit that operates by receiving power supply from the assembled battery 3. The external device may be, for example, a main part of a battery-equipped device system such as an electronic device such as a portable personal computer, a digital camera, or a mobile phone, or a vehicle such as an electric vehicle or a hybrid car. Or a power generation device such as a wind power generation device.

The connection terminal 11 is connected to the positive electrode of the assembled battery 3, that is, the positive electrode of the battery B1. The connection terminal 12 is connected to the negative electrode of the assembled battery 3, that is, the negative electrode of the battery B5. The connection terminal 13 is a connection terminal for communication.

The battery power supply device 1 charges and discharges the assembled battery 3 through the

connection terminals

11 and 12 by being connected to such an external device through the

connection terminals

11, 12 and 13. Further, the battery power supply device 1 transmits information indicating the voltages Vb1, Vb2, Vb3, Vb4, and Vb5 of the batteries B1, B2, B3, B4, and B5 to an external device through the connection terminal 13. .

The disconnection detection circuit 2 includes a control unit 21, a voltage measurement unit 22, voltage input units 23-1, 23-2, 23-3, 23-4, 23-5, a communication IF (interface) 24, capacitors C1, C2, and the like. C3, C4, C5, resistors R1, R2, R3, R4, R5, switching elements SW1, SW2, SW3, SW4, SW5, and resistors Rx1, Rx2, Rx3, Rx4, Rx5 are provided.

Hereinafter, voltage input units 23-1, 23-2, 23-3, 23-4, 23-5, capacitors C1, C2, C3, C4, C5, resistors R1, R2, R3, R4, R5, switching element SW1 , SW2, SW3, SW4, SW5 and resistors Rx1, Rx2, Rx3, Rx4, Rx5 are collectively referred to as voltage input unit 23, capacitor C, resistor R, switching element SW, and resistor Rx.

Also, the connection point of the batteries B1 and B2 is the connection point P1, the connection point of the batteries B2 and B3 is the connection point P2, the connection point of the batteries B3 and B4 is the connection point P3, and the connection of the batteries B4 and B5 Let the point be a connection point P4. Capacitors C1, C2, C3, C4, and C5 are connected in series. The connection point between the capacitors C1 and C2 is the connection point Pc1, the connection point between the capacitors C2 and C3 is the connection point Pc2, the connection point between the capacitors C3 and C4 is the connection point Pc3, and the connection point between the capacitors C4 and C5 is the connection point Pc4. To do.

The positive electrode of the battery B1 is connected to one end of the capacitor C1 through the resistor Rx1, and the connection point P1 between the battery B1 and the battery B2 is connected to the other end of the capacitor C1, that is, the connection point Pc1 through the resistor Rx2. Yes. Similarly, the connection points P2, P3, and P4 are connected to the connection points Pc2, Pc3, and Pc4 through the resistors Rx3, Rx4, and Rx5. The negative electrode of the battery B5 is connected to a terminal opposite to the connection point Pc4 in the capacitor C5 via the resistor Rx6.

The capacitors C1, C2, C3, C4, and C5 include a series circuit of a resistor R1 and a switching element SW1, a series circuit of a resistor R2 and a switching element SW2, a series circuit of a resistor R3 and a switching element SW3, and a resistor R4. And a series circuit of the switching element SW4 and a series circuit of the resistor R5 and the switching element SW5 are connected in parallel.

In addition, the voltages across the capacitors C1, C2, C3, C4, and C5 (terminal voltages) are input to the voltage input units 23-1, 23-2, 23-3, 23-4, and 23-5, respectively. .

In this case, for example, when the battery B1 is the first battery in the claims, the battery B2 corresponds to the second battery, the conductive path from the battery B1 to the capacitor C1 via the resistor Rx1 corresponds to the first conductive path, The conductive path from the battery B1 through the resistor Rx2 to the capacitor C1 (connection point Pc1) corresponds to the second conductive path. The capacitor C1, the resistor R1, the switching element SW1, the voltage input unit 23-1, and the voltage measuring unit 22 Corresponds to the first capacitor, the first resistor, the first switching element, and the first voltage detection unit. The capacitor C2, the resistor R2, the switching element SW2, the voltage input unit 23-2, and the voltage measurement unit 22 are It corresponds to two capacitors, a second resistor, a second switching element, and a second voltage detector.

For example, when the battery B2 is the first battery in the claims, the battery B3 corresponds to the second battery and the battery B1 corresponds to the third battery, and the battery B2 (connection point P1) is connected to the connection point Pc1 via the resistor Rx2. The conductive path to reach the first conductive path, the conductive path from the battery B2 through the resistor Rx3 to the connection point Pc2 corresponds to the second conductive path, the capacitor C1, the resistor R1, the switching element SW1, and the voltage input unit 23-1 and the voltage measuring unit 22 correspond to a third capacitor, a third resistor, a third switching element, and a third voltage detecting unit, and include a capacitor C2, a resistor R2, a switching element SW2, and a voltage input unit 23-2. And the voltage measuring unit 22 correspond to a first capacitor, a first resistor, a first switching element, and a first voltage detecting unit, and include a capacitor C3, a resistor R3, a switching element SW3, and Pressure input unit 23-3 and the voltage measuring unit 22, a second capacitor, a second resistor, and corresponds to the second switching element, and a second voltage detection unit.

A filter circuit is configured by the resistor Rx and the capacitor C, and noise is reduced from the voltage of the battery B detected by the voltage input unit 23 and the voltage measurement unit 22.

The switching element SW is composed of, for example, a transistor such as an FET (Field Effect Transistor) or a relay switch. The switching elements SW1, SW2, SW3, SW4, and SW5 are turned on and off in response to control signals from the control unit 21, respectively.

The control unit 21, the voltage measurement unit 22, the voltage input unit 23, and the communication IF 24 may be configured to be integrated in, for example, one IC (Integrated Circuit).

The voltage input unit 23 is a voltage input circuit that receives the terminal voltage of the corresponding capacitor C. The voltage input units 23-1, 23-2, 23-3, 23-4, and 23-5 use terminal voltages Vc1, Vc2, and Vc3 of the capacitors C1, C2, C3, C4, and C5 using, for example, voltage dividing resistors. , Vc4, Vc5 are converted into a voltage range measurable by the voltage measuring unit 22, and are output to the voltage measuring unit 22 as voltage signals indicating the terminal voltages Vc1, Vc2, Vc3, Vc4, Vc5.

The voltage measuring unit 22 is configured using, for example, a changeover switch, an analog digital converter, or the like. For example, in response to a control signal from the control unit 21, the voltage signal output from any of the voltage input units 23-1, 23-2, 23-3, 23-4, and 23-5 is changed to, for example, a changeover switch. Is selected, converted into a digital value, and output to the control unit 21.

The control unit 21 includes, for example, a CPU (Central Processing Unit) that executes predetermined arithmetic processing, a ROM (Read Only Memory) that stores a predetermined control program, and a RAM (Random Access Memory) that temporarily stores data. For example, a storage unit 214 configured using a RAM, a timer unit 215 configured using a timer circuit, and peripheral circuits thereof. And the control part 21 functions as the voltage acquisition part 211, the determination part 212, and the voltage monitoring part 213 by executing the control program memorize | stored in ROM.

The communication IF 24 presets, for example, a signal indicating each voltage of the batteries B1, B2, B3, B4, and B5 output from the voltage monitoring unit 213 and a signal indicating the occurrence of a disconnection failure output from the determination unit 212. The communication interface circuit converts the communication protocol into a communication protocol and transmits it to the external device via the connection terminal 13.

The voltage acquisition unit 211 stores the voltage value detected by the voltage measurement unit 22 with the switching element SW turned off and the voltage value detected by the voltage measurement unit 22 with the switching element SW turned on. The data is stored in the unit 214.

The determination unit 212 determines whether or not the voltage measurement conductive path is disconnected based on the voltage value stored in the storage unit 214 by the voltage acquisition unit 211 and transmits the determination result to the external device through the communication IF 24.

The voltage monitoring unit 213 uses the terminal voltages Vc1, Vc2, Vc3, Vc4, and Vc5 of the capacitors C1, C2, C3, C4, and C5 detected by the voltage measurement unit 22 in a state where the switching element SW is turned off as the battery B1. , B2, B3, B4, B5 are obtained as voltages Vb1, Vb2, Vb3, Vb4, Vb5, and a signal indicating each voltage is transmitted to the external device by the communication IF 24.

Next, the operation of the battery power supply device 1 shown in FIG. 1 will be described. 2, 3, and 4 are flowcharts illustrating an example of the operation of the battery power supply device 1. First, the normal operation in which no disconnection occurs in the conductive path and no internal short circuit occurs in the battery B will be described.

First, all of the switching elements SW1 to SWN are turned off by the voltage acquisition unit 211 (step S1). Here, “N” is the number of batteries B, and N = 5 in the assembled battery 3 shown in FIG.

When the switching element SW is turned off, the terminal voltage Vc of the capacitor C becomes equal to the voltage of the battery B. Therefore, the voltages of the batteries B1 to BN are passed through the filter composed of the resistor Rx and the capacitor C. To VcN are input to voltage input units 23-1 to 21-N, and voltage signals indicating terminal voltages Vc1 to VcN are output to voltage measurement unit 22.

Next, the voltage acquisition unit 211 causes the voltage measurement unit 22 to measure the terminal voltages Vc1 to VcN, and stores them in the storage unit 214 as the voltage values Vc1 (open) to VcN (open) (step S2).

For example, when the variable i is “2”, when the resistance value of the resistor Rx is 400Ω, the resistance value of the resistor R is 100Ω, and the voltage of the battery B2 is 3.6V, the switching element SW2 is turned off (opened). ), The voltage value Vc2 (open) becomes 3.6V and is stored in the storage unit 214.

That is, in a normal state in which there is no disconnection in the conductive path and no internal short circuit has occurred in battery B, voltage values Vc1 (open) to VcN (open) do not approach 0V, The obtained voltage value exceeds a certain value.

Next, the voltage acquisition unit 211 assigns “1” as an initial value to the variable i indicating the number of the battery B (step S3). Then, the voltage acquisition unit 211 turns on the switching element SWi (step S4). When the switching element SWi is turned on, the timer unit 215 starts counting the elapsed time. When the set time ts has elapsed after the switching element SWi is turned on (YES in step S5), the control signal from the voltage acquisition unit 211 is transmitted. Accordingly, the terminal voltage Vci is measured by the voltage measuring unit 22 and stored in the storage unit 214 as the voltage value Vci (open) (step S6).

Next, all the switching elements SW1 to SW5 are turned off by the voltage acquisition unit 211 (step S7). Next, the voltage acquisition unit 211 confirms whether or not the variable i is greater than or equal to the number N of batteries B (step S8). If the variable i is not greater than or equal to the number N (NO in step S8), the variable i After “1” is added to (step S9), steps S4 to S8 are repeated again. If the variable i is greater than or equal to the number N (YES in step S8), the process proceeds to step S11.

In step S6, if the conductive path is not disconnected, when the switching element SWi is turned on, a current path is formed from the battery Bi to the battery Bi via the resistor Rxi, the resistor Ri, the switching element SWi, and the resistor Rx (i + 1). Is done. Then, the voltage Vbi of the battery Bi is divided by the resistor Rxi, the resistor Ri, and the resistor Rx (i + 1), and the voltage generated at the resistor Ri is input to the voltage input unit 23-i as the terminal voltage Vci to measure the voltage. The voltage value Vci (close) is stored in the storage unit 214 by the unit 22.

For example, when the switching element SW2 is on (closed) (step S6), a voltage of, for example, 3.6V of the battery B2 is divided by the resistor Rx2 (400Ω), the resistor R2 (100Ω), and the resistor Rx3 (400Ω). Thus, 0.4 V corresponding to the resistor R2 is stored in the storage unit 214 as the voltage value Vc2 (close).

That is, in a normal state in which no disconnection occurs in the conductive path and no internal short circuit occurs in the battery B, the voltage value Vci (close) does not become close to 0 V, and the voltage Vbi is the resistance Rxi and the resistance Ri. , And the voltage value obtained by dividing the voltage by the resistor Rxi.

Next, the operation when a disconnection occurs in the conductive path and when an internal short circuit occurs in the battery B will be described. FIG. 5 shows a result of steps S1 to S9, as a result of a conductive path connecting the positive electrode of the battery Bi and the capacitor Ci (hereinafter referred to as a positive electrode side conductive path), and a conductive path connecting the negative electrode of the battery Bi and the capacitor Ci (hereinafter referred to as a positive electrode). The voltage value Vci (open) and the voltage value Vci (close) obtained in accordance with the combination of the presence or absence of disconnection in any one of the negative electrode-side conductive paths and the presence or absence of internal short circuit in the battery Bi. It is explanatory drawing for demonstrating.

First, when there is no disconnection in either the positive electrode side conductive path or the negative electrode side conductive path of the battery Bi and the battery Bi is not internally short-circuited (FIG. 5A), as described above, Vci (open )> 0, and the voltage value Vci (close)> 0.

Next, in the case where either the positive electrode side conductive path or the negative electrode side conductive path of the battery Bi is disconnected and the battery B is not short-circuited (FIG. 5B), for example, the connection point P1 and the connection point A case where a disconnection has occurred at a point PX on the conductive path connecting Pc1 will be described as an example.

In this case, in step S2, the terminal voltages Vc1 and Vc2 are values obtained by dividing the sum of the voltage Vb1 of the battery B1 and the voltage Vb2 of the battery B2 by the capacitor C1 and the capacitor C2. Therefore, the voltage value Vc1 (open) and the voltage value Vc2 (open) do not become 0 V, but become a certain voltage value or more, and Vci (open)> 0. Capacitors C1 to C5 have the same capacitance.

In actual use, each battery B is operated so that the battery voltages are uniform. Here, a case where the battery B1 is 4.0V and the battery B2 is 3.6V will be described as an example. When the switching elements SW1 and SW2 are in the open state, (Vb1 + Vb2) /2=3.8V is input to the voltage input units 23-1 and 23-2, respectively. Therefore, the voltage value Vc1 (open) and the voltage value Vc2 (open) are both 3.8V, and neither is 0V.

Next, when the switching element SWi, for example, the switching element SW2 is turned on in step S4, if a disconnection occurs at the point PX, the current path from the battery B2 to the resistor R2 is interrupted, and therefore based on the voltage Vb2. No voltage is generated. On the other hand, since the capacitor C2 is discharged through the resistor R2, the terminal voltage Vc2 decreases according to the time constant based on the capacitor C2 and the resistor R2, and becomes 0V.

For example, when the battery Bi is fully charged, the terminal voltage Vci is about 0 V after the switching element SWi is turned on while the capacitor Ci is charged to the full charge voltage of the battery Bi. The time required for the change (the time required for the terminal voltage Vci to fall below a second threshold voltage Vth2 described later) is preset as the set time ts.

In step S6, the terminal voltage Vc2 is acquired as the voltage value Vc2 (close) by the voltage acquisition unit 211 after the set time ts has elapsed since the switching element SW2 was turned on. Therefore, the voltage value Vc2 (close) is It becomes about 0V.

That is, when one of the positive electrode side conductive path and the negative electrode side conductive path of the battery Bi is disconnected and the battery Bi is not short-circuited (FIG. 5B), the voltage value Vci (open)> 0, the voltage The value Vci (close) ≈0.

Next, when the conductive path is not disconnected and an internal short circuit has occurred in the battery Bi, for example, the battery B2 (FIG. 5C), the voltage Vb2 becomes approximately 0 V due to the internal short circuit. Therefore, in step S2, the voltage value Vc2 (open) is also about 0V.

Similarly, in step S6, if the battery Bi, for example, the battery B2, is internally short-circuited, no current flows from the battery B2 to the resistor R2, so that the terminal voltage Vc2 becomes 0V. As a result, the voltage value Vc2 (close) also changes. Moreover, it becomes about 0V.

That is, when the conductive path is not disconnected and an internal short circuit has occurred in the battery Bi, for example, the battery B2 (FIG. 5C), the voltage value Vci (open) ≈0 and the voltage value Vci (close) ≈ 0.

Next, when either the positive electrode side conductive path or the negative electrode side conductive path of the battery Bi is disconnected and an internal short circuit has occurred in the battery Bi (FIG. 5D), the battery Bi is disconnected at, for example, the point PX. A case where an internal short circuit has occurred in B2 will be described as an example. When the conductive path is disconnected at the point PX and an internal short circuit has occurred in the battery B2, in step S2, the terminal voltages Vc1 and Vc2 are the sum of the voltage Vb1 of the battery B1 and the voltage Vb2 of the battery B2 and the capacitor C1. The value is divided by the capacitor C2.

Here, when the battery B2 is internally short-circuited, the voltage Vb2 becomes approximately 0 V, and thus the voltage value Vc1 (open) and the voltage value Vc2 (open) are both (Vb1 + 0) / 2. For example, if the voltage Vb1 is 4.0 V, the voltage value Vc1 (open) and the voltage value Vc2 (open) are both 2.0 V, and both exceed 0 V.

Next, when the switching element SWi, for example, the switching element SW2 is turned on in step S4, if a disconnection occurs at the point PX, the current path from the battery B2 to the resistor R2 is blocked, In the first place, the voltage Vb2 is about 0V due to the internal short circuit of the battery B2. Therefore, the voltage value Vci (close) is about 0V.

That is, when one of the positive electrode side conductive path and the negative electrode side conductive path of the battery Bi is disconnected and an internal short circuit has occurred in the battery Bi (FIG. 5D), the voltage value Vci (open)> 0, the voltage The value Vci (close) ≈0.

As described above, in steps S1 to S9, the voltage value Vci (open) and the voltage value Vci (close) for each battery B are acquired and stored in the storage unit 214. Next, a method for determining disconnection detection based on the voltage value Vci (open) and the voltage value Vci (close) thus obtained will be described.

First, in step S11, the determination unit 212 assigns “1” as an initial value to the variable i indicating the number of the battery B (step S11). Then, the determination unit 212 reads out the voltage value Vci (open) and the voltage value Vci (close) from the storage unit 214 (step S12).

Next, the determination unit 212 compares the voltage value Vci (open) with the first threshold voltage Vth1 (step S13). The first threshold voltage Vth1 is a determination threshold that is set in advance to determine whether or not the voltage value Vci (open) is zero. For example, a voltage value that is about the voltage measurement error of the voltage measurement unit 22 is set. .

If voltage value Vci (open) does not exceed first threshold voltage Vth1 (NO in step S13), determination unit 212 determines that voltage value Vci (open), that is, terminal voltage Vbi of battery Bi is about 0V. (Step S14), and the determination result is transmitted to the external device connected to the connection terminal 13 through the communication IF 24 (step S31).

When the voltage value Vci (open) does not exceed the first threshold voltage Vth1 and is approximately 0V, it corresponds to FIG. 5C, and it is considered that the disconnection of the conductive path does not occur. The disconnection determination process for the positive electrode side conductive path and the negative electrode side conductive path is terminated, and the process proceeds to step S32 to determine the next battery.

In step S32, the determination unit 212 compares the variable i with the number N of the batteries B. If i ≧ N (YES in step S32), the process is terminated. If i ≧ N is not satisfied (in step S32). NO), 1 is added to the variable i by the determination part 212 (step S33), and the process after step 12 is repeated again.

On the other hand, when the voltage value Vci (open) exceeds the first threshold voltage Vth1 in step S13 (YES in step S13), it is considered that one of (a), (b), and (d) in FIG. . Therefore, the determination unit 212 compares the voltage value Vci (close) with the second threshold voltage Vth2 (step S15), and if the voltage value Vci is equal to or higher than the second threshold voltage Vth2 (NO in step S15), the determination unit. 212, it is determined that the battery Bi is not short-circuited, and neither of the positive electrode side conductive path and the negative electrode side conductive path of the battery Bi is disconnected, and is normal (FIG. 5A). Step S16).

The second threshold voltage Vth2 is a determination threshold that is set in advance to determine whether or not the voltage value Vci (close) is zero. For example, a voltage value that is about the voltage measurement error of the voltage measurement unit 22 is set. . Note that the first threshold voltage Vth1 and the second threshold voltage Vth2 may be set to the same voltage.

Then, in order to monitor the voltage Vbi of the battery Bi, the voltage monitoring unit 213 transmits the voltage value Vci (open) to the external device connected to the connection terminal 13 by the communication IF 24 as the voltage Vbi of the battery Bi (step) S16). Then, the disconnection determination process for the positive electrode side conductive path and the negative electrode side conductive path of the battery Bi is terminated, and the process proceeds to step S32 in order to determine the next battery.

On the other hand, if the voltage value Vci (close) does not satisfy the second threshold voltage Vth2 in step S15 (YES in step S15), the determination unit 212 determines that the voltage value Vci (close) is about 0V. In this case, since the first condition is satisfied and corresponds to (b) or (d) in FIG. 5, it is determined that one of the positive electrode side conductive path and the negative electrode side conductive path of the battery Bi is disconnected (step S18), the process proceeds to step S19 to identify which one is disconnected.

As a result, it is determined that the conductive path is disconnected only in the case where the conductive path is disconnected ((b) or (d) in FIG. 5), the case where the conductive path is not disconnected (FIG. 5). In (a) or (c)), the possibility that the conductive path is erroneously determined to be disconnected is reduced.

Next, in step S19, the voltage value Vc (i + 1) (open) and voltage value Vc (i + 1) (close) of the (i + 1) th battery B, that is, the battery B (i + 1) connected to the negative electrode of the battery Bi are obtained. The data is read from the storage unit 214 by the determination unit 212 and compared with the first threshold voltage Vth1 and the second threshold voltage Vth2 (step S19).

When voltage value Vc (i + 1) (open) exceeds first threshold voltage Vth1 and voltage value Vc (i + 1) (close) does not satisfy second threshold voltage Vth2 (YES in step S19), battery B ( Since one of the positive electrode side conductive path and the negative electrode side conductive path of i + 1) is disconnected, the determination unit 212 combines the negative electrode side conductive path (second conductivity) of the battery Bi together with the determination result in step S18. Path), that is, it is determined that the positive electrode side conductive path of the battery B (i + 1) is disconnected.

In this case, the determination condition in step S19 corresponds to an example of the second condition.

Next, the determination unit 212 transmits the determination result to the external device connected to the connection terminal 13 through the communication IF 24 (step S31), and executes the processing after step S32 in the same manner as described above.

On the other hand, if the voltage value Vc (i + 1) (open) does not exceed the first threshold voltage Vth1 in step S19, or if the voltage value Vc (i + 1) (close) is greater than or equal to the second threshold voltage Vth2 (in step S19). NO), since the positive electrode side conductive path and the negative electrode side conductive path of the battery B (i + 1) are not disconnected, the process proceeds to step S21 in order to inspect the conductive path in the i−1th battery B.

In step S21, the voltage value Vc (i-1) (open) and voltage value Vc (i-1) of the i-1th battery B, that is, the battery B (i-1) connected to the positive electrode of the battery Bi. (Close) is read from the storage unit 214 by the determination unit 212 and compared with the first threshold voltage Vth1 and the second threshold voltage Vth2 (step S21).

When the voltage value Vc (i−1) (open) exceeds the first threshold voltage Vth1 and the voltage value Vc (i−1) (close) is less than the second threshold voltage Vth2 (YES in step S21) Since either the positive electrode side conductive path or the negative electrode side conductive path of the battery B (i-1) is disconnected, the determination unit 212 combines the determination result in step S18 with the positive electrode side of the battery Bi. It is determined that the conductive path (first conductive path), that is, the negative electrode side conductive path of the battery B (i-1) is disconnected (step S22).

In this case, the determination condition in step S21 corresponds to an example of the third condition.

On the other hand, in step S21, the voltage value Vc (i−1) (open) originally exceeds the first threshold voltage Vth1 and the voltage value Vc (i−1) (close) does not satisfy the second threshold voltage Vth2. Should be established (YES in step S21). Nevertheless, when the voltage value Vc (i−1) (open) does not exceed the first threshold voltage Vth1, or when the voltage value Vc (i−1) (close) is equal to or higher than the second threshold voltage Vth2 ( Since NO is determined in step S21), it is considered that some abnormality has occurred in the operation of the disconnection detection circuit 2. Therefore, the determination unit 212 performs an error determination indicating that the disconnection detection circuit 2 is abnormal (step S23).

As described above, even when the output voltage of a certain battery B included in the assembled battery 3 becomes close to zero due to an internal short circuit, the disconnection of the conductive path may be erroneously detected by the processes in steps S1 to S33. Can be reduced. Further, the disconnected conductive path can be specified by the processing of steps S19 to S22.

It should be noted that step S21 is not executed and the second condition is not satisfied in step S19, that is, the voltage value Vc (i + 1) (open) does not exceed the first threshold voltage Vth1, or the voltage value Vc (i + 1) ) (Close) is equal to or higher than the second threshold voltage Vth2 (NO in step S19), the process proceeds to step S22 to determine that the positive electrode side conductive path (first conductive path) of the battery Bi is disconnected. It may be.

Alternatively, steps S19 to S23 may not be executed, and in step S18, only the presence or absence of disconnection may be determined and the determination result may be transmitted (step S31).

Also, in steps S1 to S9, the configuration is shown in which the disconnection is determined after obtaining the voltage value Vci (open) and the voltage value Vci (close) of all the batteries B. However, the voltage value Vci of each battery B is shown. Each time (open) and the voltage value Vci (close) are acquired, the determination processing in steps S13 to S23 may be performed.

Further, a configuration without the resistor Rx may be adopted.

That is, the disconnection detection circuit according to one aspect of the present invention is connected to the first and second batteries connected in series via the first conductive path that is electrically connected to the terminal opposite to the second battery of the first battery. A first capacitor connected to the connection point via a second conductive path having one end connected to the terminal and the other end connected to the connection point of the first and second batteries; a first resistor; and a first switching A first circuit connected in parallel with the first capacitor, one end connected to the connection point via the second conductive path, and the other end of the second battery in the second battery A second capacitor connected to a terminal opposite to the connection point; a first voltage detection unit for detecting a voltage across the first capacitor; and the first voltage detection with the first switching element turned off. The voltage detected by the The first condition is a condition that exceeds the first threshold voltage and the voltage detected by the first voltage detector in a state where the first switching element is turned on does not satisfy a preset second threshold voltage. When it is established, a determination unit that determines that at least one of the first and second conductive paths is disconnected is provided.

According to this configuration, if the first and second conductive paths are not disconnected, when the first switching element is off, the voltage of the first battery causes the first capacitor to pass through the first and second conductive paths. Is charged, the first voltage detector can detect the voltage of the first battery by detecting the voltage across the first capacitor. Then, the voltage detected by the first voltage detector exceeds the first threshold voltage. In addition, when the first switching element is on, a current flows from the first battery to the first resistor through the first and second conductive paths. As a result, the voltage generated in the first resistor is detected by the first voltage detection unit. Detected. Then, the voltage detected by the first voltage detector exceeds the second threshold voltage.

Further, if one of the first and second conductive paths is disconnected, the voltage of two batteries sandwiching the disconnected conductive path is added when the first switching element is off. , Applied to a series circuit of two capacitors. Then, a voltage obtained by dividing the sum of the voltages of the two batteries by the two capacitors is applied to both ends of the first capacitor, and this voltage is detected by the first voltage detector. Then, the voltage detected by the first voltage detector exceeds the first threshold voltage. Also, if one of the first and second conductive paths is disconnected, when the first switching element is off, no current is supplied from the first battery to the first resistor, and the first capacitor is As a result of being discharged by the first resistor, the voltage detected by the first voltage detector decreases to near zero. Then, the voltage detected by the first voltage detection unit is less than the second threshold voltage.

Therefore, the determination unit includes the first voltage detection unit in a state where the voltage detected by the first voltage detection unit exceeds the first threshold voltage with the first switching element turned off and the first switching element is turned on. When the voltage detected by (2) is less than the second threshold voltage, it is determined that at least one of the first and second conductive paths is disconnected. At this time, if the output voltage of the first battery is close to zero, the voltage detected by the first voltage detector with the first switching element turned off is also close to zero, and the first threshold value is reached. Since the voltage is not exceeded, the risk that the determination unit erroneously determines that a disconnection has occurred can be reduced.

A second circuit and a second switching element, the second series circuit being connected in parallel with the second capacitor, and a second voltage detector configured to detect a voltage across the second capacitor. The determination unit further includes a voltage detected by the second voltage detection unit in a state where the first condition is satisfied and the second switching element is turned off exceeds the first threshold voltage, and When the second condition, which is a condition in which the voltage detected by the second voltage detector with the second switching element turned on is less than the second threshold voltage, is established, the second conductive path is disconnected. It is preferable to determine that it is present.

According to this configuration, the second resistor, the second switching element, and the second voltage detector for the second battery are the first resistor, the first switching element, and the first voltage detector for the first battery. Since the voltage detected by the second voltage detector exceeds the first threshold voltage with the second switching element turned off, the second switching element is turned on and the second switching element is turned on. When the second condition, which is a condition in which the voltage detected by the two voltage detection unit is less than the second threshold voltage, is satisfied, at least one of the conductive paths connected to both ends of the second battery is disconnected. Conceivable. Further, if the first condition is satisfied, it is considered that one of the first and second conductive paths is disconnected. Therefore, the determination unit satisfies the first condition and turns off the second switching element. In this state, the voltage detected by the second voltage detection unit exceeds the first threshold voltage, and the voltage detected by the second voltage detection unit with the second switching element turned on satisfies the second threshold voltage. If not, it is determined that the second conductive path common to the first and second batteries is disconnected.

This makes it possible to identify a disconnected conductive path.

Further, it is preferable that the determination unit determines that the first conductive path is disconnected when the first condition is satisfied and the second condition is not satisfied.

According to this configuration, if the first condition is satisfied, it is considered that one of the first and second conductive paths is disconnected. When the second condition is not satisfied, it is considered that both the conductive paths connected to both ends of the second battery are not disconnected, and therefore the second conductive path is not disconnected. Therefore, the determination unit determines that the first conductive path is disconnected. Thereby, it is possible to identify a disconnected conductive path.

In addition, a third battery is further connected in series to the first battery side of the first and second batteries, and one end is connected to the connection point of the first and third batteries via the first conductive path. The other end of the third battery is a series circuit of a third capacitor connected to a terminal opposite to the connection point of the third battery, a third resistor, and a third switching element, and is in parallel with the third capacitor. A third series circuit connected to the third capacitor; and a third voltage detector configured to detect a voltage across the third capacitor, wherein the determination unit satisfies the first condition and includes the third switching element. The voltage detected by the third voltage detector in the state of being turned off exceeds the first threshold voltage and the voltage detected by the third voltage detector in the state of turning on the third switching element is the first voltage. 2 threshold voltage When the third condition is satisfied is not condition, it is preferable to determine that the first conductive path is broken.

According to this configuration, the third resistor, the third switching element, and the third voltage detection unit for the third battery are the first resistor, the first switching element, and the first voltage detection for the first battery. The voltage detected by the third voltage detector exceeds the first threshold voltage with the third switching element turned off, and the third switching element is turned on. When the third condition, which is a condition in which the voltage detected by the three voltage detection unit is less than the second threshold voltage, is satisfied, at least one of the conductive paths connected to both ends of the third battery is disconnected. Conceivable. Further, if the first condition is satisfied, it is considered that one of the first and second conductive paths is disconnected. Therefore, the determination unit satisfies the first condition and turns off the third switching element. In this state, the voltage detected by the third voltage detection unit exceeds the first threshold voltage, and the voltage detected by the third voltage detection unit with the third switching element turned on satisfies the second threshold voltage. If not, it is determined that the first conductive path common to the first and third batteries is disconnected.

This makes it possible to identify a disconnected conductive path.

In addition, a third battery is further connected in series to the first battery side of the first and second batteries, and one end is connected to the connection point of the first and third batteries via the first conductive path. The other end of the third battery is a series circuit of a third capacitor connected to a terminal opposite to the connection point of the third battery, a third resistor, and a third switching element, and is in parallel with the third capacitor. A third series circuit connected to the third capacitor; and a third voltage detector configured to detect a voltage across the third capacitor, wherein the determination unit satisfies the first condition and includes the third switching element. The voltage detected by the third voltage detector in the state of being turned off exceeds the first threshold voltage and the voltage detected by the third voltage detector in the state of turning on the third switching element is the first voltage. 2 threshold voltage When the third condition that is not present is satisfied, it is determined that the first conductive path is disconnected, the first condition is satisfied, and both the second condition and the third condition are satisfied. If not, it is preferable to determine that an abnormality has occurred.

As described above, if the first condition is satisfied, it is considered that one of the first and second conductive paths is disconnected. Then, either the second condition or the third condition should be satisfied. Nevertheless, if neither the second condition nor the third condition is satisfied, it is considered that some abnormality has occurred in the disconnection detection circuit. Therefore, the determination unit determines that an abnormality has occurred when the first condition is satisfied and neither the second condition nor the third condition is satisfied, thereby confirming that an abnormality has occurred. Can be detected.

In addition, when the voltage detected by the first voltage detection unit is less than the first threshold voltage with the first switching element turned off, the determination unit sets the output voltage of the first battery to zero. It is preferable to determine that they are close.

As described above, when the conductive path is disconnected, the voltage detected by the first voltage detection unit with the first switching element turned off exceeds the first threshold voltage. Therefore, when the voltage detected by the first voltage detection unit with the first switching element turned off is less than the first threshold voltage, the determination unit has no disconnection of the conductive path, and the first battery It can be determined that the output voltage is close to zero.

The determination unit may be configured such that the voltage detected by the first voltage detection unit with the first switching element turned off exceeds the first threshold voltage and the first switching element is turned on. When the voltage detected by the first voltage detection unit exceeds the second threshold voltage, it is preferable to determine that the voltage is normal.

If the voltage detected by the first voltage detector with the first switching element turned off exceeds the first threshold voltage, the output voltage of the first battery does not decrease as it approaches zero, and therefore It can be determined that an internal short circuit or overdischarge of one battery has not occurred. Further, if the voltage detected by the first voltage detection unit with the first switching element turned on exceeds the second threshold voltage, the first condition is not satisfied, so the conductive path is considered not broken. It is done. Therefore, the determination unit is configured such that the voltage detected by the first voltage detection unit with the first switching element turned off exceeds the first threshold voltage and the first voltage detection unit with the first switching element turned on. When the voltage detected by (1) exceeds the second threshold voltage, it can be determined to be normal.

Further, it is preferable that a fourth resistor is provided in the first conductive path, and a fifth resistor is provided in the second conductive path.

According to this configuration, since the filter circuit is configured by the fourth resistor, the first capacitor, and the fifth resistor, noise can be reduced from the voltage detected by the first voltage detector. In this case, since the first capacitor can be used in combination for realizing the above-described disconnection detection and for configuring the filter circuit, an increase in cost can be reduced.

In addition, when the determination unit performs the determination of the first condition, the voltage detected by the first voltage detection unit after a preset time has elapsed since turning on the first switching element. It is preferable to determine whether or not is less than the second threshold voltage.

If one of the first and second conductive paths is disconnected, when the first switching element is off, the first capacitor is discharged by the first resistor as described above. The voltage of the first capacitor gradually decreases according to the time constant obtained by the first capacitor and the first resistor. Therefore, when the determination unit determines the first condition, the voltage detected by the first voltage detection unit satisfies the second threshold voltage after the set time elapses after the first switching element is turned on. By determining whether or not there is, the determination can be made after the first capacitor has been sufficiently discharged and the voltage has dropped, so the accuracy of the disconnection determination can be improved.

According to this configuration, in a power supply device using a plurality of batteries, disconnection can be detected, and even when the output voltage of a certain battery becomes close to zero, the possibility of erroneously detecting disconnection is reduced. Can do.

The disconnection detection circuit having such a configuration can reduce the possibility of erroneously detecting disconnection even when the output voltage of a certain battery among the plurality of batteries becomes close to zero.

In addition, the battery power supply device having such a configuration can detect a disconnection in a power supply device using a plurality of batteries, and even if the output voltage of a certain battery becomes close to zero, the disconnection is erroneously detected. The risk of doing so can be reduced.

This application is based on Japanese Patent Application No. 2009-222911 filed on Sep. 28, 2009, the contents of which are included in the present application.

Note that the specific embodiments or examples made in the section for carrying out the invention are to clarify the technical contents of the present invention, and are limited to such specific examples. The present invention should not be interpreted in a narrow sense, and various modifications can be made within the scope of the spirit of the present invention and the following claims.

The disconnection detection circuit according to the present invention and the battery power supply device using the disconnection detection circuit include electronic devices such as portable personal computers, digital cameras and mobile phones, vehicles such as electric vehicles and hybrid cars, hybrid elevators, solar cells and power generation devices. Can be suitably used for detecting disconnection of a circuit for detecting a plurality of battery voltages in a power supply system in which a battery and a secondary battery are combined, a battery-mounted device such as an uninterruptible power supply, and a system.

Claims

One end of the first battery and the second battery connected in series are connected to the terminal through a first conductive path that is electrically connected to the terminal opposite to the second battery, and the other end is connected to the first battery. A first capacitor connected to the connection point via a second conductive path that is electrically connected to the connection point of the first and second batteries;
A series circuit of a first resistor and a first switching element, wherein the first series circuit is connected in parallel with the first capacitor;
A second capacitor having one end connected to the connection point through the second conductive path and the other end connected to a terminal opposite to the connection point in the second battery;
A first voltage detector for detecting a voltage across the first capacitor;
The first voltage detection is performed when the voltage detected by the first voltage detection unit in a state where the first switching element is turned off exceeds a preset first threshold voltage and the first switching element is turned on. When the first condition, which is a condition that the voltage detected by the unit is less than a preset second threshold voltage, is satisfied, it is determined that at least one of the first and second conductive paths is disconnected. A disconnection detection circuit comprising a determination unit.
A series circuit of a second resistor and a second switching element, wherein the second series circuit is connected in parallel with the second capacitor;
A second voltage detector for detecting a voltage across the second capacitor;
The determination unit
The voltage detected by the second voltage detector exceeds the first threshold voltage and the second switching element is turned on when the first condition is satisfied and the second switching element is turned off. 2. It is determined that the second conductive path is disconnected when a second condition, which is a condition in which the voltage detected by the second voltage detector in a state is less than the second threshold voltage, is satisfied. Disconnection detection circuit.
The determination unit
The disconnection detection circuit according to claim 2, wherein when the first condition is satisfied and the second condition is not satisfied, it is determined that the first conductive path is disconnected.
A third battery is further connected in series to the first battery side of the first and second batteries,
A third capacitor having one end connected to a connection point of the first and third batteries via the first conductive path, and the other end connected to a terminal opposite to the connection point in the third battery;
A series circuit of a third resistor and a third switching element, wherein the third series circuit is connected in parallel with the third capacitor;
A third voltage detector for detecting a voltage across the third capacitor;
The determination unit
The voltage detected by the third voltage detector exceeds the first threshold voltage and the third switching element is turned on when the first condition is satisfied and the third switching element is turned off. The first conductive path is determined to be disconnected when a third condition, which is a condition in which the voltage detected by the third voltage detector in a state is less than the second threshold voltage, is satisfied. The disconnection detection circuit according to 2.
A third battery is further connected in series to the first battery side of the first and second batteries,
A third capacitor having one end connected to the connection point of the first and third batteries via the first conductive path and the other end connected to a terminal opposite to the connection point in the third battery;
A series circuit of a third resistor and a third switching element, wherein the third series circuit is connected in parallel with the third capacitor;
A third voltage detector for detecting a voltage across the third capacitor;
The determination unit
The voltage detected by the third voltage detector exceeds the first threshold voltage and the third switching element is turned on when the first condition is satisfied and the third switching element is turned off. When the third condition, which is a condition in which the voltage detected by the third voltage detection unit in a state is less than the second threshold voltage, is determined, the first conductive path is determined to be disconnected,
The disconnection detection circuit according to claim 2, wherein if the first condition is satisfied and neither the second condition nor the third condition is satisfied, it is determined that an abnormality has occurred.
The determination unit
2. The output voltage of the first battery is determined to be close to zero when the voltage detected by the first voltage detector with the first switching element turned off is less than the first threshold voltage. The disconnection detection circuit according to any one of 1 to 5.
The determination unit
The voltage detected by the first voltage detector with the first switching element turned off exceeds the first threshold voltage and the first voltage detector with the first switching element turned on. 7. The disconnection detection circuit according to claim 1, wherein when the detected voltage exceeds the second threshold voltage, it is determined that the voltage is normal.
A fourth resistor is provided in the first conductive path;
The disconnection detection circuit according to any one of claims 1 to 7, wherein a fifth resistor is provided in the second conductive path.
The determination unit
When determining the first condition, the voltage detected by the first voltage detector after the elapse of a preset time after turning on the first switching element becomes the second threshold voltage. 9. The disconnection detection circuit according to claim 1, wherein it is determined whether or not the condition is satisfied.
A disconnection detection circuit according to any one of claims 1 to 9,
A battery power supply device comprising: the first and second batteries.