JP2006185685A - Disconnection detecting device and disconnection detecting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To detect the disconnection of a connecting wire connected between a cell and a detecting terminal without carrying out processing for forcibly short circuiting every other detecting terminal. <P>SOLUTION: In current bypass voltage detecting circuits a1 to an, N-type MOS transistors Q1 to Qn installed at each cell is turned on when cell voltages exceed a bypass operation voltage by comparing voltages of respective cells s1 to sn with a bypass operation voltage. In abnormality detecting circuits b1 to bn, an overcharged state and an overdischarged state of corresponding cells are detected. When an overcharge abnormality detecting signal and an overdischarge abnormality detecting signal are inputted by a prescribed number of times within a prescribed time via an OR circuit 4, a battery pack 1 is charged by a charging/discharging control circuit 5, and when the overcharge abnormality detecting signal and the overdischarge abnormality detecting signal become alternatively not to be inputted afterwards, determination is made that disconnection has occurred in the connecting wire between detecting terminals C1 to Cn and cells s1 to sn. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an assembled battery cell composed of a plurality of cells, and a disconnection detection device and a disconnection detection method for detecting disconnection between control circuits.

  Conventionally, in order to detect a disconnection between a detection terminal and a cell connected to both terminals of a plurality of cells, every other detection terminal is short-circuited, and at the time of a short-circuit, it is positioned above and below the disconnection point. There is known an apparatus that determines that a disconnection has occurred when signals indicating an overdischarge abnormality and an overcharge abnormality of a cell are respectively output from an abnormality detection circuit that is present (see Patent Document 1).

JP 2004-104989 A

  However, in the conventional apparatus, when the disconnection is detected, every other detection terminal is forcibly short-circuited, so that there is a problem that discharge is performed via the discharge resistor and the heat radiation amount of the entire circuit is increased. It was.

(1) The disconnection detection device according to the present invention is provided for each cell, and when the cell voltage exceeds a predetermined bypass operating voltage, a detection resistor provided between the cells is connected via a discharge resistor. The capacity adjustment means for discharging the cell by short-circuiting, the voltage between the detection terminals and the predetermined overcharge determination voltage are compared, and the overcharge is detected when the voltage between the detection terminals is higher than the overcharge determination voltage. Overcharge abnormality detection means that outputs an abnormality detection signal, compares the voltage between the detection terminals and a predetermined overdischarge determination voltage, and detects the overdischarge abnormality when the voltage between the detection terminals is lower than the overdischarge determination voltage. An overcharge abnormality detection signal and an overdischarge abnormality detection signal are output within a predetermined time from the overdischarge abnormality detection means for outputting a signal, the charging means for charging the assembled battery, the overcharge abnormality detection means and the overdischarge abnormality detection means. Output A charging control means for charging the assembled battery by the charging means, and after charging of the assembled battery is started by the charging means, at least one of an overcharge abnormality detection signal and an overdischarge abnormality detection signal is output. And determining means for determining that the connection line connecting the detection terminal and the cell is disconnected when there is no more.
(2) The disconnection detection method according to the present invention is provided for each cell constituting the assembled battery. When the voltage of the cell exceeds a predetermined bypass operating voltage, a detection terminal provided corresponding to the cell is connected. When the voltage between the detection terminals is higher than the overcharge determination voltage by comparing the capacity adjustment circuit that discharges the cell by short-circuiting through the discharge resistor with the voltage between the detection terminals and the predetermined overcharge determination voltage The overcharge abnormality detection circuit that outputs an overcharge abnormality detection signal is compared with the voltage between the detection terminals and a predetermined overdischarge determination voltage. In a circuit including an overdischarge abnormality detection circuit that outputs a discharge abnormality detection signal, a detection terminal connected to both terminals of each cell constituting the assembled battery, and a connection line connecting between the cells Disconnection to detect disconnection After detecting the overcharge abnormality detection signal and the overdischarge abnormality detection signal being output within a predetermined time in the detection method, after performing the procedure of charging the assembled battery and the process of charging the assembled battery, And a procedure for determining that the connection line connecting the detection terminal and the cell is disconnected when at least one of the overcharge abnormality detection signal and the overdischarge abnormality detection signal is not output. It is characterized by that.

  According to the disconnection detection device and the disconnection detection method according to the present invention, the disconnection of the connection line between the cell and the detection terminal is reliably detected without performing the process of forcibly shorting every other detection terminal. be able to.

  FIG. 1 is a diagram illustrating a system configuration in which a disconnection detection apparatus according to an embodiment is applied to a hybrid vehicle. The assembled battery 1 is configured by connecting in series n chargeable / dischargeable cells s1 to sn. The DC voltage of the assembled battery 1 is converted into an AC voltage by the inverter 6 and applied to an AC motor 7 that is a travel drive source of the vehicle. The AC motor 7 is a motor generator that functions as an electric motor and also functions as a generator using an engine (not shown) as a power source. The AC voltage generated by the AC motor 7 is converted into a DC voltage by the inverter 6 and supplied to the assembled battery 1. The voltage sensor 8 detects the voltage of the assembled battery 1 and outputs it to the charge / discharge control circuit 5 described later.

  The detection terminals C0 to Cn are connected to the positive terminal or the negative terminal of each cell s1 to sn. For example, the detection terminal C0 is connected to the negative terminal of the cell s1, and the detection terminal C1 is connected to the positive terminal of the cell s1 and the negative terminal of the cell s2.

  The current bypass voltage detection circuits a1 to an are provided for each of the cells s1 to sn. When detecting that the inter-terminal voltage of the corresponding cells s1 to sn is higher than the bypass operating voltage V1, an H level signal is output. Output. When the voltage between the terminals of the corresponding cells s1 to sn is lower than the bypass operating voltage V1, an L level signal is output. Here, a state in which a current is flowing is a state in which an H level signal is being output, and a state in which a current is not flowing is a state in which an L level signal is being output.

  N-type MOS transistors Q1 to Qn are provided for each cell. Signals output from the current bypass voltage detection circuits a1 to an are input to the gate terminals of the corresponding N-type MOS transistors Q1 to Qn. For example, when an H level signal is output from the current bypass voltage detection circuit a1, the N-type MOS transistor Q1 is turned on. Thereby, a current flows from the cell s1 through the discharge resistor R1 connected in series with the N-type MOS transistor Q1.

  That is, the current bypass voltage detection circuit a1, the discharge resistor R1, and the N-type MOS transistor Q1 constitute a current bypass circuit of the cell s1, and when the voltage of the cell s1 becomes higher than the bypass operating voltage V1, Discharge occurs. Similarly, current bypass voltage detection circuits a2 to an, discharge resistors R2 to Rn, and N-type MOS transistors Q2 to Qn constitute current bypass circuits for cells s2 to sn, respectively. Becomes higher than the bypass operating voltage V1, the corresponding cells s2 to sn are discharged. With such a configuration, the voltage value between the cells can be kept uniform.

  The abnormality detection circuits b1 to bn are provided for the respective cells s1 to sn, and the inter-terminal voltage (detection terminal voltage) of the corresponding cells s1 to sn rises above the overcharge determination threshold voltage V2, While detecting that the battery is overcharged, the voltage between the terminals of the cell drops below the overdischarge determination threshold voltage V3, and it is detected that the cell is overdischarged. When the overcharge state or overdischarge state of the cell is detected, an abnormality detection signal (H level) is output to the OR circuit 4. However, the overcharge abnormality detection signal and the overdischarge abnormality detection signal can be distinguished from each other by, for example, a method in which current values are different. The OR circuit 4 performs a logical sum operation on the outputs of the abnormality detection circuits b1 to bn and outputs the calculation result to the charge / discharge control circuit 5. That is, when an overcharge abnormality detection signal or an overdischarge abnormality detection signal is output from any one of the abnormality detection circuits b1 to bn, the overcharge abnormality detection signal or the overdischarge abnormality detection signal is charged via the OR circuit 4. Input to the discharge control circuit 5. The magnitude relationship among the three predetermined voltages V1, V2, and V3 is set to V2> V1> V3.

  The charge / discharge control circuit 5 detects an overcharge abnormality or overdischarge abnormality of the cell based on a signal from the OR circuit 4 and, between the cells s1 to sn and the detection terminals C0 to Cn, by a method described later. The disconnection of each connected connection line is detected.

  Here, the operation of the current bypass circuit when the connection lines connecting the cells s1 to sn and the detection terminals C0 to Cn are disconnected and the operation of the abnormality detection circuits B1 to Bn will be described. Keep it. Here, description will be made assuming that the connection line between the positive electrode of the cell s2 and the detection terminal C2 is disconnected. The voltage value of each cell s1 to sn is assumed to be lower than the bypass operating voltage V1 and higher than the overdischarge determination threshold voltage V3. Therefore, in this state, all the N-type MOS transistors Q1 to Qn are turned off, and no abnormality detection signal is output from any of the abnormality detection circuits b1 to bn.

  As the assembled battery 1 is charged, the voltages of the cells s1 to sn rise, and for example, the voltage of the cell s2 becomes higher than the bypass operating voltage V1. In this case, since the H level signal is output from the current bypass voltage detection circuit a2, the N-type MOS transistor Q2 is turned on. FIG. 2 is a diagram showing a state in which the N-type MOS transistor Q2 is turned on. As a result, the voltage value of the detection terminal C1 and the voltage value of the detection terminal C2 become equal, so the voltage between the detection terminals C2 and C3 is the voltage between the detection terminals C1 and C3, that is, the voltage of the cell s2 and the voltage of the cell s3. It becomes the voltage which added the voltage. Therefore, an H level signal is output from the current bypass voltage detection circuit a3, the N-type MOS transistor Q3 is turned on, and an overcharge abnormality detection signal is output from the abnormality detection circuit b3.

  As described above, since the voltage value of the detection terminal C1 and the voltage value of the detection terminal C2 are equal, the signal level of the signal output from the current bypass voltage detection circuit a2 is L level, and the N-type MOS transistor Q2 Turn off. Further, an overdischarge abnormality detection signal is output from the abnormality detection circuit b2.

  FIG. 3 is a diagram showing a state in which the N-type MOS transistor Q3 is turned on and the N-type MOS transistor Q2 is turned off. When the N-type MOS transistor Q3 is turned on, the voltage value of the detection terminal C2 and the voltage value of the detection terminal C3 become equal. Therefore, the voltage between the detection terminals C1 and C2 is the voltage between the detection terminals C1 and C3, that is, This is a voltage obtained by adding the voltage of the cell s2 and the voltage of the cell s3. Therefore, an H level signal is output from the current bypass voltage detection circuit a2, the N-type MOS transistor Q2 is turned on, and an overcharge abnormality detection signal is output from the abnormality detection circuit b2.

  Further, as described above, since the voltage value of the detection terminal C2 and the voltage value of the detection terminal C3 are equal, the signal level of the signal output from the current bypass voltage detection circuit a3 is L level, and the N-type MOS transistor Q3 is Turn off. The abnormality detection circuit b3 outputs an overdischarge abnormality detection signal.

  In the above description, the case where the connection line between the positive electrode of the cell s2 and the detection terminal C2 is broken is taken as an example, but the case where the connection line between another cell and the corresponding detection terminal is broken is also mentioned. It is the same. That is, when the connection line connecting the cells s1 to sn and the detection terminals C0 to Cn is disconnected, the N-type MOS transistors positioned above and below the disconnected connection line are alternately turned on and disconnected. Overcharge abnormality detection signals and overdischarge abnormality detection signals are alternately output from the abnormality detection circuits located above and below the connection line. FIG. 4 is a diagram illustrating voltage fluctuation between the detection terminals C1 and C2.

  FIG. 5 is a flowchart showing the content of the disconnection detection process performed by the charge / discharge control circuit 5. When an ignition switch (not shown) is turned on, the charge / discharge control circuit 5 starts the process of step S10. In step S10, it is determined whether or not the overcharge abnormality detection signal and the overdischarge abnormality detection signal are each input n times from the OR circuit 4 during m (seconds). Here, m is 0.1 and n is 3. As described above, when the disconnection occurs in the connection line, the overcharge abnormality detection signal and the overdischarge abnormality detection signal are alternately output from the abnormality detection circuits located above and below the location where the disconnection has occurred. If the determination in step S10 is negative, the process waits in step S10. If the determination is positive, the process proceeds to step S20.

  In step S20, it is determined whether or not the total voltage value of the assembled battery 1 detected by the voltage sensor 8 is equal to or less than a predetermined threshold value. The predetermined threshold is a value obtained by multiplying the overcharge determination threshold voltage V2 by the number of cells n. If it determines with the total voltage value of the assembled battery 1 being below a predetermined threshold value, it will progress to step S30, and if it determines with it being larger than a predetermined threshold value, it will progress to step S70.

  In step S <b> 30, a command for charging the assembled battery 1 is issued to the inverter 6. Thereby, the control which charges the assembled battery 1 using the electric power generated by the regenerative operation of the AC motor 7 is started.

  In the above description, a disconnection occurs in the connection line connecting the cell and the detection terminal, and the current bypass circuit when one of the N-type MOS transistors located above and below the disconnection point is turned on. The operation and the operation of the abnormality detection circuits B1 to Bn have been described. Here, a case will be described in which the potential of each cell rises due to charging of the assembled battery 1, and both N-type MOS transistors positioned above and below the disconnection portion of the connection line are turned on. Similar to the above description, consider the case where the connection line between the positive electrode of the cell s2 and the detection terminal C2 is disconnected. When N-type MOS transistors Q2 and Q3 located above and below the disconnected connection line are turned on, current flows from the positive electrode of cell s3 to the negative electrode of cell s2 via resistors R3 and R2. Since the resistance values of the resistors R1 to Rn are set to be equal to each other, the voltage between the detection terminals C1 and C2 is equal to the voltage between the detection terminals C2 and C3.

  That is, the voltage between the detection terminals C1 and C2 and the voltage between the detection terminals C2 and C3 are values obtained by adding the voltage of the cell s2 and the voltage of the cell s3 and dividing the result by two. The circuit does not output the overcharge abnormality detection signal and the overdischarge abnormality detection signal. When the value obtained by adding the voltage of the cell s2 and the voltage of the cell s3 and dividing by 2 becomes higher than the overcharge determination threshold voltage V2, an overcharge abnormality detection signal is output from the abnormality detection circuits b2 and b3. Is done. However, also in this case, the overdischarge abnormality detection signal is not output.

  In step S40 following step S30, it is determined whether or not the overcharge abnormality detection signal and the overdischarge abnormality detection signal that are alternately input are no longer input. Either the overcharge abnormality detection signal and the overdischarge abnormality detection signal are not input, or one of the overcharge abnormality detection signal and the overdischarge abnormality detection signal is not input. If it is determined that the process has been completed, the process proceeds to step S50. Otherwise, the process proceeds to step S70.

  In step S50, it is determined that a disconnection has occurred in the connection line connecting the cell and the detection terminal, and the process proceeds to step S60. In step S60, a charge stop command for the assembled battery 1 is issued to the inverter. Thereby, the charging of the assembled battery 1 is stopped, and the process of the flowchart shown in FIG. 5 ends.

  On the other hand, in step S70, an overcharge abnormality detection process or an overdischarge abnormality detection process for each of the cells s1 to sn is performed. The overcharge abnormality detection process is a process for confirming whether or not there is a cell in an overcharge state, and the overdischarge abnormality detection process is for determining whether or not there is a cell in an overdischarge state. It is a process to confirm. Since these abnormality detection processes can use known processes, detailed description thereof is omitted here. When the overcharge abnormality detection process or the overdischarge abnormality detection process is performed, the process of the flowchart shown in FIG. 5 ends.

  According to the disconnection detecting device in one embodiment, when it is detected from the abnormality detection circuits b1 to bn that the overcharge abnormality detection signal and the overdischarge abnormality detection signal are output a predetermined number of times within a predetermined time, the assembled battery 1 and after that, when at least one of the overcharge abnormality detection signal and the overdischarge abnormality detection signal is not output, the connection line connecting the cell and the detection terminal is disconnected. Is determined to have occurred. Thereby, unlike the conventional disconnection detection method, it is not necessary to short-circuit every other detection terminal, so that the problem that the amount of heat generation increases during the disconnection detection process does not occur. In addition, the conventional method of short-circuiting every other detection terminal also causes a problem that the voltage between cells varies, but such a problem occurs according to the disconnection detection device in one embodiment. Nor.

  In a state where no disconnection occurs, the overcharge abnormality detection signal and the overdischarge abnormality detection signal are not detected a predetermined number of times within a predetermined time, but the overcharge abnormality detection is detected by the charge / discharge control circuit 5 due to noise. The signal and the overdischarge abnormality detection signal may be input alternately. However, in the case of noise, even if the assembled battery 1 is charged, the overcharge abnormality detection signal and the overdischarge abnormality detection signal are still input alternately. That is, according to the disconnection detection device in one embodiment, since the signal when the connection line is disconnected can be distinguished from the signal due to noise, the disconnection of the connection line can be reliably detected.

  Further, according to the disconnection detection device in one embodiment, when it is detected that the overcharge abnormality detection signal and the overdischarge abnormality detection signal are output a predetermined number of times within a predetermined time from the abnormality detection circuits b1 to bn. However, when the total voltage of the assembled battery 1 is higher than a predetermined voltage, the charging process of the assembled battery 1 for detecting disconnection is not performed. This can prevent the cells s1 to sn from being overcharged.

  The present invention is not limited to the embodiment described above. For example, although the example which applied the disconnection detection apparatus to the hybrid vehicle was demonstrated, it can also apply to an electric vehicle and can also be applied to systems other than a vehicle. When applied to a system other than a vehicle, power generation means may be provided in place of the AC motor 7 functioning as a generator. Further, an indicator may be added to the configuration shown in FIG. 1 and when the disconnection of the connection line is detected, the indicator may be turned on to notify the driver that the disconnection has occurred.

  Although the abnormality detection circuits b1 to bn have a function of detecting cell overcharge abnormality and overdischarge abnormality, the overcharge abnormality detection circuit for detecting cell overcharge abnormality and the cell overdischarge abnormality are detected. An overdischarge abnormality detection circuit may be provided separately.

  The correspondence between the constituent elements of the claims and the constituent elements of the embodiment is as follows. That is, the abnormality detection circuits b1 to bn are overcharge abnormality detection means and overdischarge abnormality detection means, the current bypass voltage detection circuits a1 to an, the discharge resistors R1 to Rn and the N-type MOS transistors Q1 to Qn are capacity adjustment means. The AC motor 7 constitutes charging means, and the charge / discharge control circuit 5 constitutes charging control means and determination means. In addition, the above description is an example to the last, and when interpreting invention, it is not limited to the correspondence of the component of said embodiment and the component of this invention at all.

The figure which shows the system configuration which applied the disconnection detection apparatus in one embodiment to the hybrid vehicle The figure which shows the state which N type MOS transistor Q2 turned on The figure which shows the state which N type MOS transistor Q3 turned on and N type MOS transistor Q2 turned off The figure which shows the voltage fluctuation between the detection terminals of the disconnection location when the disconnection of the connection line occurs Flow chart showing contents of disconnection detection processing performed by charge / discharge control circuit

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Battery assembly, 4 ... OR circuit, 5 ... Charge-discharge control circuit, 6 ... Inverter, 7 ... AC motor, 8 ... Voltage sensor, a1-an ... Current bypass voltage detection circuit, b1-bn ... Abnormality detection circuit, C1 ˜Cn... Detection terminal, s1 to sn... Cell, Q1 to Qn... N type MOS transistor, R1 to Rn.

Claims (5)

In the disconnection detecting device for detecting disconnection of the connection terminals connecting between the detection terminals connected to both terminals of the plurality of cells constituting the assembled battery and the cells,
A capacity that discharges a cell by short-circuiting the detection terminals provided for each cell when the cell voltage exceeds a predetermined bypass operating voltage via a discharge resistor. Adjusting means;
An overcharge abnormality detecting means for comparing the voltage between the detection terminals with a predetermined overcharge determination voltage and outputting an overcharge abnormality detection signal when the voltage between the detection terminals is higher than the overcharge determination voltage; ,
An overdischarge abnormality detecting means for comparing the voltage between the detection terminals and a predetermined overdischarge determination voltage and outputting an overdischarge abnormality detection signal when the voltage between the detection terminals is lower than the overdischarge determination voltage; ,
Charging means for charging the assembled battery;
When detecting that the overcharge abnormality detection signal and the overdischarge abnormality detection signal are output within a predetermined time from the overcharge abnormality detection means and the overdischarge abnormality detection means, the battery pack is charged by the charging means. Charging control means
When at least one of the overcharge abnormality detection signal and the overdischarge abnormality detection signal is not output after charging of the assembled battery is started by the charging means, the detection terminal and the cell are connected. A disconnection detecting device comprising: a determination unit that determines that the connected connection line is disconnected. The disconnection detecting device according to claim 1,
The charge control means, when detecting that the overcharge abnormality detection signal and the overdischarge abnormality detection signal are output a predetermined number of times within the predetermined time, causes the assembled battery to be charged by the charging means. Disconnection detection device. In the disconnection detecting device according to claim 1 or 2,
A voltage detecting means for detecting the voltage of the assembled battery;
The disconnection detecting device, wherein the charging control means causes the charging means to charge the assembled battery when the voltage of the assembled battery detected by the voltage detecting means is equal to or lower than a predetermined voltage. In the disconnection detecting device according to claim 3,
The disconnection detecting device, wherein the predetermined voltage is a value obtained by multiplying the overcharge determination voltage by the number of cells constituting the assembled battery. It is provided for each cell that constitutes the assembled battery, and when the cell voltage exceeds a predetermined bypass operating voltage, the detection terminals provided corresponding to the cell are short-circuited via a discharge resistor, whereby the cell Compares the voltage between the detection terminals and a predetermined overcharge determination voltage with the capacity adjustment circuit that discharges the battery, and outputs an overcharge abnormality detection signal when the voltage between the detection terminals is higher than the overcharge determination voltage An overcharge abnormality detection circuit that compares the voltage between the detection terminals and a predetermined overdischarge determination voltage, and outputs an overdischarge abnormality detection signal when the voltage between the detection terminals is lower than the overdischarge determination voltage. In a circuit including an overdischarge abnormality detection circuit, a disconnection detection method for detecting disconnection of a connection terminal connecting between a detection terminal connected to both terminals of each cell constituting the assembled battery and the cell Is
A procedure for charging an assembled battery upon detecting that the overcharge abnormality detection signal and the overdischarge abnormality detection signal are output within a predetermined time;
After performing the process of charging the assembled battery, when at least one of the overcharge abnormality detection signal and the overdischarge abnormality detection signal is not output, the connection connecting the detection terminal and the cell A disconnection detecting method comprising: determining that the line is disconnected.

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