JP3823840B2 - Voltage detection device for battery pack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembled battery voltage detection device.
[0002]
[Prior art]
As a battery for driving an electric vehicle, an assembled battery composed of a plurality of single cells is known. An apparatus for controlling the charge / discharge power of such an assembled battery is disclosed in, for example, Japanese Patent Laid-Open No. 9-312939. According to this power control apparatus, the assembled battery detects the terminal voltage of each single cell by the cell controller, and the terminal voltage (total voltage) of the assembled battery is detected by the voltage sensor.
[0003]
[Problems to be solved by the invention]
In the conventional power control apparatus, the control value of charge / discharge power is calculated using the total voltage, and the control value is corrected using the terminal voltage of the single cell. For this reason, when a voltage sensor fails and the total voltage of an assembled battery is not detected, there exists a possibility that a correct control value may not be calculated.
[0004]
An object of the present invention is to provide an assembled battery voltage detection device that detects the voltage of an assembled battery by the voltage of each unit battery (single cell) even when the terminal voltage of the assembled battery is not detected.
[0005]
[Means for Solving the Problems]
(1) The invention described in claim 1 is applied to a voltage detection device for an assembled battery including a plurality of unit batteries. A unit voltage detection circuit that is provided for each unit battery and detects the voltage of the unit battery; a total voltage calculation circuit that calculates a sum of a plurality of unit battery voltages detected by the unit voltage detection circuit; and a terminal of the assembled battery A total voltage detection circuit that detects the voltage, a diagnostic circuit that determines whether there is an abnormality in the total voltage detection circuit, and (1) when no abnormality is determined by the diagnostic circuit, the terminal voltage is the detection voltage of the assembled battery, (2) When the presence of abnormality is determined by the diagnostic circuit, the above-described object is achieved by including a control circuit that uses the total voltage as the detection voltage of the assembled battery.
(2) The invention according to claim 2 calculates the difference between the terminal voltage when the assembled battery is unloaded and the total voltage when the assembled battery is unloaded in the assembled battery voltage detecting device according to claim 1. The control circuit further includes a difference calculating circuit that corrects the sum voltage with the difference when the diagnostic circuit determines that there is an abnormality.
(3) The invention according to claim 3 is the assembled battery voltage detection device according to claim 1 or 2, wherein the detection result by the unit voltage detection circuit and the detection result by the total voltage detection circuit are temporally matched. And a timing control circuit.
(4) The invention according to claim 4 is the assembled battery voltage detection device according to any one of claims 1 to 3, further comprising a temperature detection circuit for detecting the temperature of the total voltage detection circuit itself, and a control circuit Is characterized by correcting the terminal voltage according to the temperature detected by the temperature detection circuit when it is determined that there is no abnormality in the diagnostic circuit.
(5) The invention according to claim 5 is applied to a voltage detection device for an assembled battery including a plurality of unit batteries. A unit voltage detection circuit that is provided for each unit battery and detects the voltage of the unit battery; a total voltage calculation circuit that calculates a sum of a plurality of unit battery voltages detected by the unit voltage detection circuit; and a terminal of the assembled battery A total voltage detection circuit for detecting voltage, a difference calculation circuit for calculating a difference between a terminal voltage when the assembled battery is not loaded and a total voltage when the assembled battery is not loaded, a detection result by the unit voltage detection circuit, and a total A timing control circuit that time-matches the detection result of the voltage detection circuit, a diagnosis circuit that determines whether the total voltage detection circuit is abnormal, and (1) the terminal voltage when the abnormality is determined by the diagnostic circuit. (2) When it is determined that there is an abnormality in the diagnostic circuit, the total voltage of multiple unit battery voltages time-aligned by the timing control circuit is corrected with the difference to By providing exit and a control circuit for the voltage to achieve the above object.
(6) According to the sixth aspect of the present invention, in the assembled battery voltage detection device according to the fifth aspect, the diagnostic circuit is configured such that the difference between the terminal voltage and the total voltage exceeds the first predetermined value and the unit voltage According to whether or not all of the plurality of unit battery voltages detected by the detection circuit are within a second predetermined value with respect to the average value of the plurality of unit battery voltages, Total voltage detection circuit It is characterized by determining the presence or absence of abnormality.
[0006]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, even if abnormality arises in the circuit which detects the terminal voltage of an assembled battery, the voltage of an assembled battery can be detected using the voltage of each unit battery.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. In the following embodiments, an example in which an assembled battery is applied as a power source of an electric vehicle will be described. FIG. 1 is an overall configuration diagram of an assembled battery for a vehicle according to an embodiment of the present invention. In FIG. 1, the assembled battery includes 40 cells C1 to C40 connected in series, and eight cells C1 to C40 are grouped to constitute five module batteries M1 to M5. In addition, the number of cells constituting the assembled battery and each module battery is not limited to the quantity according to the present description. Cell controllers C / C1, C / C2,..., C / C5 are connected to the five module batteries M1 to M5, respectively. The five cell controllers C / C1 to C / C5 each have a CPU, a memory, and a timer, and manage eight cells constituting the module battery Mn for each module battery. Here, n is an integer of 1-5. The electric power from the assembled battery is supplied to a vehicle system that controls the vehicle. Here, the vehicle system includes an inverter, a motor, and the like for driving the vehicle by being supplied with the power of the assembled battery, and the total voltage Va ′ (load) of the assembled battery transmitted from the battery controller B / C or It includes a vehicle controller that performs capacity display of the capacity meter and vehicle running control by the total voltage Vb (load).
[0008]
The cell controller C / Cn has a voltage detection circuit which will be described later, and individually detects the voltages of the eight single cells in each module battery Mn when detecting the cell voltage. The single cell voltage detection timing is controlled by a timer, and the single cell detection voltage is stored in a memory in each cell controller C / Cn. The cell controller C / Cn performs failure diagnosis of the voltage detection circuit in the cell controller C / Cn using the voltage detection value of the single cell. Specifically, an average value Vave of eight detected single cell voltage values is calculated, and at least one of the eight single cell voltage values has a difference equal to or greater than a predetermined voltage threshold with respect to the average value Vave. In addition, it is considered that abnormality has occurred in the voltage detection circuit and abnormal data has occurred in the voltage detection value. Such failure diagnosis is performed every time the voltage of the single cell is detected.
[0009]
The cell controller C / Cn further outputs a signal for adjusting the capacity of each of the eight single cells constituting each module battery Mn. The cell capacity adjustment will be described later. The cell controller C / Cn is supplied with electric power from each module battery Mn. The CPU of each cell controller C / Cn has a built-in communication interface, and communicates with the battery controller B / C via this communication interface. Cell controllers C / C1 to C / C5 are managed by battery controller B / C.
[0010]
The CPUs of the cell controllers C / C1 to C / C5 are turned on when an on signal is transmitted from the battery controller B / C and are turned off when an off signal is transmitted.
[0011]
The battery controller B / C includes a CPU 204, a memory 205, and a timer 206. The CPU 204 of the battery controller B / C has a built-in communication interface, and communicates with each cell controller C / Cn. The battery controller B / C controls the cell controllers C / C1 to C / C5 through this communication, and receives battery information and diagnostic information from the cell controllers C / C1 to C / C5.
[0012]
The battery information is a voltage value of a single cell in each module battery Mn detected by the voltage detection circuit of each cell controller C / C1 to C / C5 when the cell voltage is detected. The battery information received by the battery controller B / C is stored in the memory 205 in the battery controller B / C and used for the control of the cell controllers C / C1 to C / C5, or the capacity display of a capacity meter (not shown). Used for etc. Overcharge occurs when the voltage value of the single cell is higher than a predetermined voltage range, and overdischarge occurs when the voltage value of the single cell is lower than the predetermined voltage range. Thus, the state of charge can be determined from the voltage value of the single cell.
[0013]
The diagnosis information is abnormality data when abnormality is detected in the voltage detection result in the cell controllers C / C1 to C / C5. The diagnostic information received by the battery controller B / C is stored in the memory 205 in the battery controller B / C and used for failure diagnosis in the battery controller B / C.
[0014]
The battery controller B / C instructs each of the five cell controllers C / C1 to C / C5 to detect the voltage of all the single cells constituting each module battery Mn and to adjust the capacity of each single cell. Output a signal. The battery controller B / C further calculates the battery capacity and battery deterioration state for displaying the capacity of a capacity meter (not shown), and manages the vehicle with signals such as the calculated battery capacity and battery deterioration state. Output to a controller (not shown). Further, when the battery controller B / C receives the abnormal data from any of the cell controllers C / C1 to C / C5, the battery controller B / C causes the indicator ID to be lit and displayed.
[0015]
The power of the battery controller B / C is supplied from the auxiliary battery B. Battery controller B / C is turned on / off in conjunction with an ignition switch (not shown) of the vehicle.
[0016]
The voltage sensor 201 detects the total voltage of the assembled battery and outputs a detection signal to the battery controller B / C. The total voltage is a voltage detected by connecting five module batteries M1 to M5 constituting the assembled battery in series. The detection timing of the total voltage is controlled by the timer 206 of the battery controller B / C, and the detected total voltage value is stored in the memory 205 in the battery controller B / C. The current sensor 202 detects a current flowing through the assembled battery and outputs a detection signal to the battery controller B / C. The detected current value is stored in the memory 205 in the battery controller B / C. The temperature sensor 203 detects the temperature of the voltage sensor 201 and outputs a detection signal to the battery controller B / C. The detected temperature value is stored in the memory 205 in the battery controller B / C.
[0017]
The battery controller B / C performs predetermined arithmetic processing using the total voltage value detected by the voltage sensor 201 and the current value detected by the current sensor 202, and controls the charge / discharge power of the assembled battery.
[0018]
FIG. 2 is a circuit block diagram in the cell controller C / C1. Here, the cell controller C / C1 will be described as an example, but the other cell controllers C / C2 to C / C5 are the same as the cell controller C / C1. In FIG. 2, the module battery M1 and the cell controller C / C1 are connected. The module battery M1 is configured by connecting eight cells C1 to C8 in series. The cell controller C / C1 has a CPU, eight differential amplifiers D1 to D8, and eight capacitance adjustment circuits E1 to E8. The capacitance adjustment circuits E1 to E8 are provided with capacitance adjustment circuit switches SWb1 to SWb8 and resistors R1 to R8, respectively.
[0019]
The eight differential amplifiers D1 to D8 individually detect the terminal voltages Vc1 to Vc8 of the single cells C1 to C8, respectively, and output the detection voltages Vd1 to Vd8 when the cell voltage is detected. The CPU incorporates an A / D conversion circuit (not shown), and converts the detection voltages Vd1 to Vd8 output from the differential amplifiers D1 to D8 into digital values, respectively. The CPU performs management of the cells C1 to C8 and failure diagnosis of the voltage detection circuit based on the digitally converted voltage data. Here, the voltage detection circuit includes differential amplifiers D1 to D8. The CPU transmits the battery information of the single cells C1 to C8 and the diagnostic information of the differential amplifiers D1 to D8 to the battery controller B / C by serial communication. The transmitting terminal is Tx and the receiving terminal is Rx.
[0020]
The capacity adjustment circuits E1 to E8 discharge the single cells C1 to C8, respectively. The capacity adjustment circuit switches SWb1 to SWb8 are turned on by an on signal sent from the CPU and turned off by an off signal. When the capacity adjustment circuit switches SWb1 to SWb8 are turned on, the single cells C1 to C8 are discharged through the corresponding resistors R1 to R8. The CPU determines the capacity adjustment circuit switch corresponding to this cell for the cell for which the variation in the capacity of the single cell is determined from the voltage detection data described above (specifically, it indicates a voltage higher than the single cell voltage average value of C1 to C8). Turn on to discharge.
[0021]
The battery controller B / C controls each of the cell controllers C / C1 to C / C5 based on the information transmitted by serial communication from the cell controllers C / C1 to C / C5 as described above. In normal control performed while the vehicle is running or charging the battery, charge / discharge control of the assembled battery is performed based on the total voltage detected by the voltage sensor 201 and transmitted from the cell controllers C / C1 to C / C5. The cell controller C / C1 to C / C5 is instructed to adjust the capacity of the single cell according to the battery information. When abnormal data is sent from the cell controllers C / C1 to C / C5 to the battery controller B / C, an alarm is displayed on the indicator ID to notify the driver of the abnormality and fail-safe operation (input / output restriction etc.) )I do.
[0022]
In the present invention, when an abnormality occurs in the voltage sensor 201, the total voltage is calculated using the voltage detection value of the single cell detected by the cell controller C / Cn, and is detected by the calculated total voltage value and the current sensor 202. It is characterized in that charge / discharge power of the assembled battery is controlled using the measured current value.
[0023]
Processing performed by the battery controller B / C will be described. FIG. 3 is a flowchart for explaining the flow of processing executed by the CPU 204 of the battery controller B / C. The process according to FIG. 3 is started in conjunction with turning on the ignition switch of the vehicle. In step S11 of FIG. 3, power is supplied to the CPU 204 from the auxiliary battery B, the CPU 204 is activated, and the process proceeds to step S12. In step S12, the CPU 204 performs an initial diagnosis process and proceeds to step S13. The initial diagnosis process is a process for diagnosing a battery in a no-load state. Details of the initial diagnosis process will be described later.
[0024]
In step S13, the CPU 204 performs a normal diagnosis process. The normal diagnosis process is a battery diagnosis process performed while the vehicle is running. Details of the normal diagnosis process will be described later. When the CPU 204 finishes the normal diagnosis process, it ends the process shown in FIG. Note that the processing in FIG. 3 ends when the ignition switch is turned off even during subroutine processing to be described later.
[0025]
FIG. 4 is a flowchart for explaining a subroutine of the initial diagnosis process. In step S21 of FIG. 4, the CPU 204 sets the value of the abnormality determination flag A to the initial value 0, and proceeds to step S22. The abnormality determination flag A is a flag that is set to 1 when the voltage sensor 201 is abnormal, 2 when the voltage detection circuit of the cell controller C / Cn is abnormal, and 0 when both are normal.
[0026]
In step S22, the CPU 204 stores the total voltage value Va detected by the voltage sensor 201 in the memory 205 in the battery controller B / C, and proceeds to step S23. In step S <b> 23, the CPU 204 instructs each of the five cell controllers C / C <b> 1 to C / C <b> 5 to detect voltages of all the single cells constituting each module battery Mn. Thereby, the voltage detection of each single cell is performed by the cell controllers C / C1 to C / C5. The CPU 204 calculates the sum of the voltage detection values of a total of 40 single cells transmitted from the cell controllers C / C1 to C / C5, and stores the calculated sum voltage value Vb in the memory 205 in the battery controller B / C. Then, the process proceeds to step S24.
[0027]
In step S24, the CPU 204 determines whether or not the difference between the total voltage value Va and the total voltage value Vb is equal to or less than a predetermined value Y. If | Va−Vb | ≦ Y is satisfied, the CPU 204 makes a positive determination in step S24 and proceeds to step S25. If | Va−Vb | ≦ Y does not hold, the CPU 204 makes a negative determination in step S24 and proceeds to step S26. . When the process proceeds to step S25, it is regarded as normal, and when the process proceeds to step S26, it is regarded as abnormal.
[0028]
In step S25, the CPU 204 stores the absolute value V = | Va−Vb | of the difference between the total voltage value Va and the total voltage value Vb in the memory 205 in the battery controller B / C, and ends the process of FIG. . The value of the difference V corresponds to a detection error between the voltage sensor 201 and the voltage detection circuits of the cell controllers C / C1 to C / C5. On the other hand, in step S26, the CPU 204 performs a fail safe (F / S) process and ends the process of FIG.
[0029]
FIG. 5 is a flowchart for explaining the details of a subroutine of fail-safe processing. In step S31, the CPU 204 determines whether or not there is a failure in the voltage detection circuits of the cell controllers C / C1 to C / C5. The CPU 204 requests the cell controllers C / C1 to C / C5 to transmit diagnostic information, and stores the diagnostic information transmitted from the cell controllers C / C1 to C / C5 in the memory 205. The CPU 204 considers that a failure has occurred in the voltage detection circuits of the cell controllers C / C1 to C / C5 when abnormal data is stored in the diagnostic information of the memory 205, and makes an affirmative decision in step S31. Proceed to On the other hand, if the abnormal data is not stored in the diagnosis information, the CPU 204 makes a negative determination in step S31 and proceeds to step S32.
[0030]
In step S32, the CPU 204 considers that a failure has occurred in the voltage sensor 201 and proceeds to step S33. In step S33, the CPU 204 sets the value of the abnormality determination flag A to 1 and proceeds to step S35. In step S34, the CPU 204 sets the value of the abnormality determination flag A to 2 and proceeds to step S35. In step S35, the CPU 204 outputs a warning display lighting request to the indicator ID, and ends the process of FIG. As a result, the driver is notified of the abnormality.
[0031]
FIG. 6 is a flowchart for explaining a subroutine of normal diagnosis processing. In step S41 of FIG. 6, the CPU 204 determines whether or not normality is determined in the initial diagnosis process. If the abnormality determination flag A = 0, the CPU 204 makes a positive determination in step S41 and proceeds to step S42. If A ≠ 0, the CPU 204 makes a negative determination in step S41 and proceeds to step S48.
[0032]
In step S42, the CPU 204 causes the timer 206 to start measuring time and determines whether or not the measured time T is a predetermined time Tn. The predetermined time Tn is a battery diagnosis (voltage check) interval in the normal diagnosis. When the time count T = Tn is established, the CPU 204 makes a positive determination in step S42 and proceeds to step S43. When T = Tn is not satisfied, the CPU 204 makes a negative determination in step S42 and continues the time measurement.
[0033]
In step S43, the CPU 204 stores the total voltage value Va (load) detected by the voltage sensor 201 in the memory 205 in the battery controller B / C, and proceeds to step S44. In step S44, the CPU 204 corrects the total voltage value Va (load) according to the temperature detected by the temperature sensor 203, and stores the total voltage value Va ′ (load) after the temperature correction in the memory 205, and then in step S45. Proceed to
[0034]
FIG. 7 is a diagram illustrating the temperature correction coefficient of the voltage sensor 201. In FIG. 7, the horizontal axis is the temperature, and the vertical axis is the correction coefficient. Voltage sensor 201 according to the present embodiment has a temperature characteristic in which the voltage detection value becomes smaller on the higher temperature side than 25 ° C. and on the lower temperature side than 25 ° C. when expressed on the basis of 25 ° C. Therefore, a total voltage value Va ′ (load) converted to 25 ° C. is calculated by multiplying the total voltage detection value Va (load) by the voltage sensor 201 by a coefficient corresponding to the temperature value detected by the temperature sensor 203. 7 is stored in advance in a memory (not shown) in the CPU 204.
[0035]
In step S <b> 45, the CPU 204 instructs each of the five cell controllers C / C <b> 1 to C / C <b> 5 to detect voltages of all the single cells constituting each module battery Mn. The instruction to each cell controller C / Cn is sequentially performed by the communication described above. Thereby, each of the cell controllers C / C1 to C / C5 performs voltage detection of a single cell. The CPU 204 calculates the sum of the voltage detection values of a total of 40 single cells transmitted from the cell controllers C / C1 to C / C5, stores the calculated sum voltage value Vb (load) in the memory 205, and performs step S46. Proceed to
[0036]
Here, the timing of voltage detection will be described. FIG. 8 is a diagram for explaining timing at which voltage detection is performed by the five cell controllers C / C1 to C / C5 and the voltage sensor 201. Each cell controller C / Cn is configured to store a single cell voltage detected during a predetermined time Δt in a memory in the cell controller C / C. At time t1 in FIG. 8, the cell controller C / C1 receives a command from the CPU 204 in the battery controller B / C, detects the single cell voltage for a time Δt, and stores the detected value in the memory.
[0037]
At time t2, the cell controller C / C2 receives a command from the CPU 204 in the battery controller B / C, detects the single cell voltage for a time Δt, and stores the detected value in the memory. Thereafter, similarly, the cell controller C / C3, the cell controller C / C4, and the cell controller C / C5 detect the single cell voltage for the time Δt from the time point of the timing t3, the timing t4, and the timing t5, respectively, and store the detected value in the memory. Store.
[0038]
At timing t6, the CPU 204 outputs a command to the voltage sensor 201 to detect the total voltage under load. When the CPU 204 causes the cell controllers C / C1 to C / C5 to transmit the single cell voltage detection value, the voltage detection value stored in the memory in each cell controller C / Cn corresponds to the timing t6. The CPU of each cell controller C / Cn is instructed to transmit the voltage detection value. As a result, the voltage detection timing of the single cell matches the detection timing of the total voltage. Note that the timing at which the current sensor 202 detects the current is also controlled to coincide with the timing t6.
[0039]
In step S46, the CPU 204 determines whether or not the difference between the temperature-corrected total voltage value Va ′ (load) and the total voltage value Vb (load) is equal to or smaller than a predetermined value Z. When | Va ′ (load) −Vb (load) | ≦ Z is established, the CPU 204 makes a positive determination in step S46 and returns to step S42, and | Va ′ (load) −Vb (load) | ≦ Z is established. If not, a negative determination is made in step S46, and the process proceeds to step S47. The case of returning to step S42 is a case of normality, and the above-described single cell voltage detection and total voltage detection are repeated every predetermined time Tn. In this case, the charge / discharge power of the battery pack is controlled using the total voltage value Va ′ (load) detected by the voltage sensor 201 and subjected to temperature correction, and the current value detected by the current sensor 202. .
[0040]
In step S48, which proceeds after making a negative determination in step S41 described above, the CPU 204 determines whether or not the abnormality determination flag A = 1. If the abnormality determination flag A = 1 (failure has occurred in the voltage sensor 201), the CPU 204 makes a positive determination in step S48 and proceeds to step S48A, where A = 2 (in the voltage detection circuit of the cell controllers C / C1 to C / C5). If a failure has occurred), the determination in step S48 is negative and the determination process is repeated. This is because the determination process is repeated when A = 2, but the detection of the single cell voltage is not performed by the failed voltage detection circuit. In this case, the total voltage value Va (load) is detected by the voltage sensor 201, and the charge / discharge power of the assembled battery is controlled using the total voltage value Va (load) and the current value detected by the current sensor 202. Is done.
[0041]
In step S48A, the CPU 204 instructs the five cell controllers C / C1 to C / C5 to detect the voltages of all the single cells constituting each module battery Mn. Thereby, each of the cell controllers C / C1 to C / C5 performs voltage detection of a single cell. The CPU 204 calculates the sum of the voltage detection values of a total of 40 single cells transmitted from the cell controllers C / C1 to C / C5, stores the calculated sum voltage value Vb (load) in the memory 205, and performs step S49. Proceed to
[0042]
In step S49, the CPU 204 calculates Va (load) = Vb (load) + V and returns to step S48A. However, V is the difference between the no-load total voltage value Va and the no-load total voltage value Vb stored in the memory 205 by the initial diagnosis process. Thereby, when an abnormality occurs in the voltage sensor 201, the total voltage value Va (load) is calculated using the voltage detection value of the single cell detected by the cell controller C / Cn, and the calculated total voltage value Va ( load) and the current value detected by the current sensor 202 are used to control the charge / discharge power of the battery pack.
[0043]
In step S47, which proceeds after making a negative determination in step S46 described above, the CPU 204 performs a fail-safe (F / S) process and returns to step S42. FIG. 9 is a flowchart for explaining the details of the fail-safe processing subroutine. In step S51, the CPU 204 determines whether or not there is a failure in the voltage detection circuits of the cell controllers C / C1 to C / C5. The CPU 204 requests the cell controllers C / C1 to C / C5 to transmit diagnostic information, and stores the diagnostic information transmitted from the cell controllers C / C1 to C / C5 in the memory 205. The CPU 204 considers that a failure has occurred in the voltage detection circuits of the cell controllers C / C1 to C / C5 when abnormal data is stored in the diagnostic information of the memory 205, and makes an affirmative determination in step S51 to perform a step S53. Proceed to In this case, the charge / discharge power of the assembled battery is controlled using the total voltage value Va ′ (load) detected by the voltage sensor 201 and temperature-compensated and the current value detected by the current sensor 202. .
[0044]
On the other hand, the CPU 204 considers that a failure has occurred in the voltage sensor 201 when no abnormal data is stored in the diagnostic information, and makes a negative determination in step S51 and proceeds to step S52. In step S52, the CPU 204 calculates Va (load) = Vb (load) + V, and proceeds to step S53. However, V is the difference between the no-load total voltage value Va and the no-load total voltage value Vb stored in the memory 205 by the initial diagnosis process. Thereby, when an abnormality occurs in the voltage sensor 201, the total voltage value Va (load) is calculated using the voltage detection value of the single cell detected by the cell controller C / Cn, and the calculated total voltage value Va ( load) and the current value detected by the current sensor 202 are used to control the charge / discharge power of the battery pack.
[0045]
In step S53, the CPU 204 outputs a warning display lighting request to the indicator ID, and ends the process of FIG. As a result, the driver is notified of the abnormality.
[0046]
The embodiment described above will be summarized.
(1) The battery controller B / C performs an initial diagnosis process of the assembled battery in a no-load state, and the terminal voltage of the assembled battery, that is, the total voltage value Va and the 40 unit cell voltages constituting the module batteries M1 to M5 And a difference V = | Va−Vb | between the two is calculated and stored in the memory 205. As a result, the detection error between the voltage sensor 201 that detects the total voltage Va and the voltage detection circuit of each cell controller C / Cn can be known.
(2) When the detection error V exceeds the predetermined value Y, it is regarded as an abnormality and the fail-safe process (FIG. 5) is performed, so that the driver can be notified of the occurrence of the abnormality.
(3) When detecting eight unit cell voltages in each cell controller C / Cn, an average value Vave of the detected eight unit cell voltage values is calculated, and at least one of the eight unit cell voltage values is between the average value Vave. Is regarded as abnormal in the voltage detection circuit on the cell controller C / Cn side. As a result, when the detection error V exceeds the predetermined value Y, it is possible to distinguish between an abnormality on the voltage sensor 201 side and an abnormality on the cell controller C / Cn side. When the cause of the failure is isolated, it is possible to perform a treatment according to the cause of the failure when the failure occurs.
(4) The battery controller B / C performs normal diagnosis processing of the assembled battery at normal time such as when the vehicle is running, and configures the terminal voltage of the assembled battery, that is, the total voltage value Va (load) and the module batteries M1 to M5. A total voltage value Vb (load) of the single cell voltages is obtained. The temperature of the voltage sensor 201 is detected by the temperature sensor 203, and the total voltage value Va ′ (load) after temperature correction is calculated to determine whether or not | Va ′ (load) −Vb (load) | Judgment was made. Since the total voltage value can be corrected by compensating the temperature characteristics of the voltage sensor 201, the detection accuracy of the total voltage can be increased.
(5) The battery controller B / C controls the charge / discharge power of the assembled battery as follows.
{Circle over (1)} When Va ′ (load) −Vb (load) | is equal to or smaller than a predetermined value Z, the total voltage value Va ′ (load) after temperature correction and the current value detected by the current sensor 202 are used. The charge / discharge power of the assembled battery is controlled.
(2) | Va ′ (load) −Vb (load) | exceeds the predetermined value Z and the voltage detection circuit on the cell controller C / Cn side is abnormal (affirmative determination in step S51), the temperature corrected The charge / discharge power of the assembled battery is controlled using the total voltage value Va ′ (load) and the current value detected by the current sensor 202.
(3) A single cell detected by the cell controller C / Cn when | Va ′ (load) −Vb (load) | exceeds a predetermined value Z and the voltage sensor 201 is abnormal (negative determination in step S51). The total voltage value Va (load) = Vb (load) + V is calculated using the detected voltage value of the battery, and the assembled battery is calculated using the calculated total voltage value Va (load) and the current value detected by the current sensor 202. To control the charge / discharge power.
(4) When the abnormality of the voltage detection circuit on the cell controller C / Cn side is determined in the initial diagnosis process (determination is negative in step S48), the total voltage value Va (load) by the voltage sensor 201 and the current sensor 202 are detected. The charge / discharge power of the assembled battery is controlled using the current value.
(5) When the abnormality of the voltage sensor 201 is determined in the initial diagnosis process (Yes in step S48), the total voltage value Va (load) is determined using the voltage detection value of the single cell detected by the cell controller C / Cn. ) = Vb (load) + V is calculated, and the charge / discharge power of the assembled battery is controlled using the calculated total voltage value Va (load) and the current value detected by the current sensor 202.
As described in (3) and (5) above, the CPU 204 of the battery controller B / C controls the charge / discharge power of the assembled battery using the total voltage Vb (load) even when an abnormality occurs in the voltage sensor 201. be able to. At this time, in the calculation of the total voltage Va, the correction is made with the detection error V between the voltage sensor 201 and the voltage detection circuit of each cell controller C / Cn. The control value of the discharge power does not change greatly before and after the abnormality of the voltage sensor 201 occurs. In addition, the capacity display of the capacity meter (not shown) does not change greatly before and after the occurrence of the abnormality of the voltage sensor 201.
(6) Since the voltage detection timing of the single cell by the voltage detection circuit of each cell controller C / Cn and the detection timing of the total voltage by the voltage sensor 201 are matched, the voltage sensor 201 and each cell controller C / The detection error V between the voltage detection circuit of Cn can be suppressed. In particular, in a vehicle having a large current fluctuation frequency, there is a high possibility that the detected voltage value differs depending on the voltage detection timing. By matching the voltage detection timing and suppressing the detection error V, the control value of the charge / discharge power does not change significantly before and after the occurrence of the abnormality of the voltage sensor 201 as in (5) above.
[0047]
In the above description, each cell controller C / Cn is configured to store the single cell voltage detected during the predetermined time Δt in the memory in the cell controller C / Cn, and the memory in each cell controller C / Cn. Among the voltage detection values stored in the battery sensor B / C, the voltage detection value corresponding to the time t6 that coincides with the detection timing of the voltage sensor 201 is transmitted to the battery controller B / C. The time matching between the voltage detection circuits of / Cn is taken. Instead, each cell controller C / Cn is made to detect a single cell voltage at the same time at timing t6, so that time matching is achieved between the voltage sensor 201 and the voltage detection circuit of each cell controller C / Cn. Also good.
[0048]
In the above description, an electric vehicle has been described as an example. However, the present invention can be applied to any vehicle having an assembled battery such as a hybrid vehicle (HEV) equipped with an engine and a motor.
[0049]
The correspondence between each component in the claims and each component in the embodiment of the invention will be described. For example, the cells C1 to C40 correspond to the unit batteries. The unit voltage detection circuit includes, for example, differential amplifiers D1 to D8. The total voltage calculation circuit, the diagnosis circuit, the control circuit, and the difference calculation circuit are configured by the CPU 204, for example. The total voltage corresponds to the terminal voltage. The total voltage detection circuit is constituted by a voltage sensor 201, for example. The timing control circuit includes, for example, a CPU 204, a timer 206, CPUs of cell controllers C / C1 to C / C5, a memory, and a timer. The temperature detection circuit is configured by a temperature sensor 203, for example. The first predetermined value corresponds to, for example, a predetermined value Z (predetermined value Y). The second predetermined value corresponds to a predetermined voltage threshold. In addition, as long as the characteristic function of this invention is not impaired, each component is not limited to the said structure.
[Brief description of the drawings]
FIG. 1 is an overall configuration diagram of an assembled battery for a vehicle according to an embodiment of the present invention.
FIG. 2 is a circuit block diagram in a cell controller.
FIG. 3 is a flowchart illustrating a flow of processing executed by a CPU of a battery controller.
FIG. 4 is a flowchart for explaining a subroutine of initial diagnosis processing;
FIG. 5 is a flowchart for explaining a subroutine of fail-safe processing.
FIG. 6 is a flowchart illustrating a subroutine of normal diagnosis processing.
FIG. 7 is a diagram illustrating a temperature correction coefficient of a voltage sensor.
FIG. 8 is a diagram illustrating timing at which voltage detection is performed by a cell controller and a voltage sensor.
FIG. 9 is a flowchart for explaining a subroutine of fail-safe processing.
[Explanation of symbols]
201 ... voltage sensor, 202 ... current sensor,
203 ... Temperature sensor, 204 ... CPU,
205 ... memory, 206 ... timer,
B / C ... battery controller, C1-C40 ... cell,
C / C1 to C / C5 ... cell controller,
D1 to D8 ... differential amplifier, E1 to E8 ... capacitance adjustment circuit,
ID: indicator, M1-M5: module battery,
SWb1 to SWb8: Capacitance adjustment circuit switch

Claims (6)

In the voltage detection device of the assembled battery composed of a plurality of unit batteries,
A unit voltage detection circuit that is provided for each unit battery and detects the voltage of the unit battery;
A total voltage calculation circuit for calculating a total of a plurality of unit battery voltages detected by the unit voltage detection circuit;
A total voltage detection circuit for detecting a terminal voltage of the assembled battery;
A diagnostic circuit for determining the presence or absence of an abnormality in the total voltage detection circuit;
(1) When no abnormality is determined by the diagnostic circuit, the terminal voltage is set as a detection voltage of the assembled battery. (2) When the abnormality is determined by the diagnostic circuit, the total voltage is determined by the assembled battery. A battery pack voltage detection apparatus comprising: a control circuit configured to detect voltage. In the assembled battery voltage detection device according to claim 1,
A difference calculating circuit for calculating a difference between the terminal voltage when the assembled battery is unloaded and the total voltage when the assembled battery is unloaded;
The control circuit corrects the total voltage with the difference when the diagnosis circuit determines that there is an abnormality. In the voltage detection apparatus of the assembled battery according to claim 1 or 2,
An assembled battery voltage detection device, further comprising a timing control circuit that temporally matches a detection result of the unit voltage detection circuit and a detection result of the total voltage detection circuit. In the voltage detection apparatus of the assembled battery in any one of Claims 1-3,
A temperature detection circuit for detecting the temperature of the total voltage detection circuit itself;
The control circuit corrects the terminal voltage in accordance with the temperature detected by the temperature detection circuit when the diagnosis circuit determines that there is no abnormality. In the voltage detection device of the assembled battery composed of a plurality of unit batteries,
A unit voltage detection circuit that is provided for each unit battery and detects the voltage of the unit battery;
A total voltage calculation circuit for calculating a total of a plurality of unit battery voltages detected by the unit voltage detection circuit;
A total voltage detection circuit for detecting a terminal voltage of the assembled battery;
A difference calculating circuit that calculates a difference between the terminal voltage when the assembled battery is unloaded and the total voltage when the assembled battery is unloaded;
A timing control circuit that takes a time match between a detection result by the unit voltage detection circuit and a detection result by the total voltage detection circuit;
A diagnostic circuit for determining the presence or absence of an abnormality in the total voltage detection circuit;
(1) When no abnormality is determined by the diagnostic circuit, the terminal voltage is set as a detection voltage of the assembled battery, and (2) when the abnormality is determined by the diagnostic circuit, the timing control circuit determines the time A battery pack voltage detection apparatus comprising: a control circuit that corrects a sum voltage of a plurality of matched unit battery voltages with the difference to obtain a battery pack detection voltage. The assembled battery voltage detection device according to claim 5,
In the diagnostic circuit, a difference between the terminal voltage and the total voltage exceeds a first predetermined value, and all of the plurality of unit battery voltages detected by the unit voltage detection circuit are averages of the plurality of unit battery voltages. An assembled battery voltage detection device that determines whether or not the total voltage detection circuit is abnormal depending on whether the value is within a second predetermined value or not.

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