JP3698056B2 - Voltage detection device for battery pack for electric vehicles - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a voltage detection device for an assembled battery for an electric vehicle.
[0002]
[Prior art]
In general, an assembled battery including a plurality of unit batteries (hereinafter referred to as cells) is used as a battery for driving an electric vehicle. Each cell of the assembled battery is divided into a predetermined number of cells called modules (collectively called a module battery), and the cells constituting the module battery are managed by a cell controller provided for each module battery. Each cell controller is supplied with power from the module battery it manages. On the other hand, a battery controller that controls each cell controller to manage the assembled battery is provided on the vehicle side, and data is transmitted and received between the cell controller and the battery controller by serial communication. At the time of charge / discharge, the battery controller performs charge / discharge control based on the cell voltage data transmitted from the cell controller.
[0003]
Here, a circuit for detecting the voltage of each cell is provided, and a technique for performing failure diagnosis of the detection circuit itself is known. FIG. 7 is a block diagram of a conventional voltage detection circuit that detects the voltage of each cell constituting the module battery. In FIG. 7, the module battery and the cell controller are connected. The module battery is composed of eight cells C1 to C8. The cell controller is provided with two differential amplifiers A1 and D1, A2 and D2,..., A8 and D8 between the respective terminals of the cells C1 to C8. Detected by. For example, the voltage value Vc1 of the cell C1 is detected by the differential amplifiers A1 and D1. The CPU of the cell controller checks the charging state of the cell C1 based on the detection voltage Va1 from the differential amplifier A1 and the detection voltage Vd1 from the differential amplifier D1. The capacity adjustment circuits E1 to E8 are circuits that suppress variations in the charging state as a predetermined state (for example, an average voltage) by discharging the corresponding cells when the charging states of the cells C1 to C8 are uneven. is there. When the CPU of the cell controller determines the variation in the charging state of the cell C1 based on the detection voltages Va1 and Vd1, the CPU C1 discharges the cell C1 via the capacity adjustment circuit E1. In such a voltage detection circuit, the CPU of the cell controller determines that one of the differential amplifiers A1 and D1 has failed when the difference between the voltage values detected by the two differential amplifiers is equal to or greater than a predetermined value Vng. to decide.
[0004]
[Problems to be solved by the invention]
In the conventional voltage detection circuit, since two differential amplifiers are provided for each cell constituting the module battery, the cost of the circuit is high.
[0005]
An object of the present invention is to provide a voltage detection device that performs voltage detection of a cell (unit battery) and failure diagnosis of the voltage detection circuit itself at a low cost.
[0006]
[Means for Solving the Problems]
  A voltage detection device according to a first aspect of the present invention is applied to a vehicle that is driven by using an assembled battery for an electric vehicle including a plurality of unit batteries as a power source, and generates a predetermined voltage for each unit battery. And a voltage detection circuit for detecting the voltage generated by the voltage generation circuit and the voltage of the unit battery, and a voltage detected by the voltage detection circuit when the voltage of the unit battery is detected by the voltage detection circuit While the voltage detection circuit detects the voltage generated from the voltage generation circuit, the voltage detection circuit performs fault diagnosis according to the voltage detected by the voltage detection circuit. And a diagnostic device for performing.
A voltage detection device according to a second aspect of the present invention is applied to a vehicle that is driven by using an assembled battery for an electric vehicle including a plurality of unit batteries as a power source, and generates a predetermined voltage for each unit battery. And a voltage detection circuit for detecting the voltage generated by the voltage generation circuit and the voltage of the unit battery, and a voltage detected by the voltage detection circuit when the voltage of the unit battery is detected by the voltage detection circuit While the voltage detection circuit detects the voltage generated from the voltage generation circuit, the voltage detection circuit performs fault diagnosis according to the voltage detected by the voltage detection circuit. A first diagnostic device to be performed; a second diagnostic device for performing a fault diagnosis of the voltage detection circuit and the first diagnostic device based on a voltage detected by the voltage detection circuit and a diagnostic result by the first diagnostic device; With It is characterized in.
According to a third aspect of the present invention, in the voltage detection device for an assembled battery for an electric vehicle according to the second aspect, the voltage detected by the voltage detection circuit and the first voltage between the first diagnostic device and the second diagnostic device. The second diagnostic device further includes a communication circuit for performing a fault diagnosis of the communication circuit based on the received detection voltage and the diagnostic result.
According to a fourth aspect of the present invention, in the voltage detection apparatus for an assembled battery for an electric vehicle according to any one of the first to third aspects, the connection between the voltage detection circuit and the unit battery is turned on / off. And a second switch circuit for turning on / off the connection between the voltage generation circuit and the voltage detection circuit. The voltage detection circuit includes a second switch when the first switch circuit is turned on. When the circuit is turned off, the voltage of the unit battery is detected by detecting the voltage of the unit battery, and when the first switch circuit is turned off and the second switch circuit is turned on, the voltage is connected to the voltage generation circuit. The voltage generated from the generation circuit is detected.
According to a fifth aspect of the present invention, in the voltage detection device for an assembled battery for an electric vehicle according to any one of the first to fourth aspects, the unit is provided for each unit battery, and the capacity of the unit battery is determined by the diagnostic device. A capacity adjustment circuit for discharging the unit battery when it is diagnosed that adjustment is necessary is further provided, and a voltage generated by the voltage generation circuit is applied to the voltage detection circuit via the capacity adjustment circuit.
[0007]
In the section of means for solving the above problems, the present invention is associated with the drawings of the embodiments for easy understanding. However, the present invention is not limited to the embodiments.
[0008]
【The invention's effect】
  As described above in detail, the present invention has the following effects.
(1) Claim 1~ 5Invention described inThe voltageUnit battery voltage by detection circuitButdetectionWhenWhile diagnosing the state of charge of the unit battery, the voltage detection circuitButdetectionWhenThe fault diagnosis of the voltage detection circuit was performed. Therefore, failure diagnosis by two voltage detection circuits as in the prior art is not required, and voltage detection and failure diagnosis of a unit battery can be performed by one voltage detection circuit. As a result, the number of parts is reduced to reduce the cost of the apparatus, and the reliability of the apparatus is improved as the number of parts is reduced.
(2) In the invention described in claims 2 and 3,Based on a predetermined voltage value detected by the voltage detection circuit and a diagnosis result by the first diagnosis device that performs failure diagnosis of the voltage detection circuit according to the voltage value, the second diagnosis deviceOf the voltage detection circuit and the first diagnostic deviceA failure diagnosis was performed. Therefore, since the failure of the first diagnostic device and the failure of the voltage detection circuit can be determined independently, the recovery work is facilitated when the failure occurs.
(3) In the invention according to claim 3,Since it is possible to determine a failure of the communication circuit provided between the first diagnostic device and the second diagnostic device, it is easy to perform a recovery operation when a failure occurs.
(4) In the invention described in claim 5,Since the voltage generated by the voltage generation circuit is applied to the voltage detection circuit via the capacitance adjustment circuit, it is not necessary to add a new circuit for failure diagnosis. As a result, an increase in the cost of the apparatus can be suppressed.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
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. Each of the five cell controllers C / C1 to C / C5 has a CPU, a ROM, and a RAM, and manages eight cells in the module battery Mn for each module battery Mn. Here, n is an integer of 1-5.
[0010]
The cell controller C / Cn is a voltage detection circuit described later.
1. While detecting the voltage of each of the eight cells in each module battery Mn when detecting the cell voltage,
2. A diagnostic reference voltage is detected during failure diagnosis.
Further, the cell controller C / Cn outputs a signal for adjusting the capacity of each of the eight cells in each module battery Mn. The cell capacity adjustment will be described later. The power of the cell controller C / Cn is supplied from each module battery Mn.
[0011]
The five cell controllers C / C1 to C / C5 are managed by the battery controller B / C. The battery controller B / C includes a CPU, a ROM, a RAM, and a communication interface circuit (not shown). The communication interface circuit communicates with each cell controller C / C1 to C / C5 by serial communication. The battery controller B / C uses the serial communication to control the cell controllers C / C1 to C / C5, 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 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 received battery information is stored in the RAM of the battery controller B / C, and is used for control of the cell controllers C / C1 to C / C5 or used for capacity display of a capacity meter (not shown). When the voltage value of the cell is higher than the predetermined voltage range, the battery is overcharged. When the voltage value of the cell is lower than the predetermined voltage range, the battery is overdischarged. The diagnosis information is a diagnosis reference voltage value detected by the voltage detection circuit of each cell controller C / C1 to C / C5 at the time of failure diagnosis, and an abnormality flag when an abnormality is detected by the failure diagnosis. The received diagnostic information is stored in the RAM of the battery controller B / C and used for failure diagnosis in the battery controller B / C.
[0013]
From the battery controller B / C, a signal for adjusting the capacity of each cell constituting each module battery Mn is output to each of the five cell controllers C / C1 to C / C5. The battery controller B / C further calculates a battery capacity and a battery deterioration state for displaying the capacity of a capacity meter (not shown), and controls the vehicle with signals such as the calculated battery capacity and the battery deterioration state. Output to a controller (not shown). The power of the battery controller B / C is supplied from the auxiliary battery B.
[0014]
The cell controllers C / C1 to C / C5 are powered on when an on signal is transmitted from the battery controller B / C, and are powered off when an off signal is transmitted. The battery controller B / C is turned on / off in conjunction with the on / off of charging of the vehicle switch and the assembled battery.
[0015]
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 includes a power switch SWm, a central processing circuit (hereinafter referred to as microcomputer) CPU, a diagnostic reference voltage unit Vs, eight differential amplification units D1 to D8, and eight capacitance adjustment circuits E1 to E1. E8 and eight cell voltage detection switches SWa1 to SWa8. The diagnostic reference voltage unit Vs includes a voltage regulator IC1, a voltage amplifier circuit IC2, and a cell reference voltage source switch SWc. The capacitance adjustment circuits E1 to E8 are provided with capacitance adjustment circuit switches SWb1 to SWb8 and resistors R1 to R8, respectively.
[0016]
The power switch SWm is turned on by a power-on signal sent from the battery controller B / C and turned off by a power-off signal sent from the battery controller B / C. When power is supplied from the module battery M1, the voltage regulator IC1 DC / DC converts the input voltage and outputs a voltage of, for example, 5V. The voltage amplifier circuit IC2 amplifies the input voltage of 5V and outputs a voltage of 30V, for example. The cell reference voltage source switch SWc is turned on by an on signal sent from the microcomputer CPU at the time of failure diagnosis, and turned off by an off signal sent after the failure diagnosis.
[0017]
Each of the cell voltage detection switches SWa1 to SWa8 is turned on by an on signal sent from the microcomputer CPU when the cell voltage is detected, and turned off by an off signal sent at the time of failure diagnosis. The eight differential amplifiers D1 to D8 detect the terminal voltages Vc1 to Vc8 of the cells C1 to C8, respectively, and output the detection voltages Vd1 to Vd8 when the cell voltage is detected. Further, at the time of failure diagnosis, each cell reference voltage for diagnosis is detected, and detection voltages Vd1 to Vd8 are output. The microcomputer CPU includes an A / D conversion circuit, and converts the detection voltages Vd1 to Vd8 output from the differential amplifiers D1 to D8 into digital signals. The microcomputer CPU performs management of the cells C1 to C8 and failure diagnosis of the voltage detection circuit based on the detection data obtained by digital conversion. Here, the voltage detection circuit includes a diagnostic reference voltage unit Vs, capacitance adjustment circuits E1 to E8, and differential amplification units D1 to D8. The microcomputer CPU also incorporates a communication interface circuit. The microcomputer CPU transmits the battery information of the 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.
[0018]
The capacity adjustment circuits E1 to E8 discharge the cells C1 to C8. The capacity adjustment circuit switches SWb1 to SWb8 are turned on by an on signal sent from the microcomputer CPU and turned off by an off signal. When the capacity adjustment circuit switches SWb1 to SWb8 are turned on, the cells C1 to C8 are discharged through the corresponding resistors R1 to R8. The microcomputer CPU turns on the capacity adjustment circuit switch corresponding to the cell for which the cell capacity variation (specifically, a voltage higher than the average value of C1 to C8) is determined from the voltage detection data described above. Discharge. The capacity adjustment circuits E1 to E8 are further used at the time of failure diagnosis. The microcomputer CPU sends an on signal to the capacity adjustment circuit switches SWb1 to SWb8 at the time of failure diagnosis, and sends an off signal after the failure diagnosis.
[0019]
At the time of failure diagnosis, the cell voltage detection switches SWa1 to SWa8 are turned off and the cell reference voltage source switch SWc is turned on. At this time, when the capacitance adjustment circuit switches SWb1 to SWb8 are turned on, the cell reference voltage of 30 V output from the voltage amplification circuit IC2 is applied to the eight capacitance adjustment circuits E1 to E8. Here, since the resistance values of the resistors R1 to R8 constituting the capacitance adjusting circuits E1 to E8 are the same, a voltage of 30/8 = 3.75 V is theoretically applied to each of the differential amplifiers D1 to D8. Applied. The microcomputer CPU determines that the differential amplifying unit is normal when the cell reference voltage value detected by the differential amplifying unit is detected with a difference of less than 0.15 V with respect to 3.75 V, for example. When the difference is detected by 0.15 V or more, it is determined that a failure has occurred in the differential amplifier. A voltage value (here 3.75V) that should be theoretically detected by the differential amplifier is given to the microcomputer CPU in advance.
[0020]
The battery controller B / C controls the cell controllers C / C1 to C / C5 based on the battery information transmitted by serial communication as described above. In normal (during traveling or charging), the battery controller B / C Among the information, the voltage detection information and the abnormality detection information obtained from the failure diagnosis result are sent from the cell controllers C / C1 to C / C5 to the battery controller B / C. The battery controller B / C performs charge / discharge control based on the voltage detection information, notifies the driver of the abnormality by a warning display or the like based on the abnormality detection information, and performs a fail-safe operation (input / output restriction, etc.).
[0021]
Processing performed by the microcomputer CPU of the battery controller B / C will be described with reference to a flowchart. FIGS. 3 and 4 are flowcharts for explaining the flow of processing performed by the microcomputer CPU of the battery controller B / C, which is activated in conjunction with turning on charging of the vehicle switch and the assembled battery. In step S10 of FIG. 3, the microcomputer CPU determines whether or not the ignition switch is turned on. If the ignition switch is turned on, an affirmative decision is made in step S10 and the process proceeds to step S15. If the ignition switch is not turned on, a negative decision is made in step S10 and the determination process is repeated.
[0022]
In step S15, the microcomputer CPU transmits a power-on signal to the cell controllers C / C1 to C / C5 and proceeds to step S20. In step S20, the microcomputer CPU transmits a signal for starting failure diagnosis of the voltage detection circuit to the cell controllers C / C1 to C / C5, and proceeds to step S25. In step S25, the microcomputer CPU determines whether or not the reception of the failure diagnosis information from the cell controllers C / C1 to C / C5 has been completed. When reception of the diagnostic information is completed, an affirmative determination is made in step S25 and the process proceeds to step S30. If no diagnostic information is received, a negative determination is made in step S25 and the process returns to step S20.
[0023]
In step S30, the microcomputer CPU stores the received diagnostic information in the RAM and proceeds to step S35. In step S35, the microcomputer CPU determines whether or not each detected voltage value by the voltage detection circuit (differential amplification unit) of the cell controllers C / C1 to C / C5 is normal. The detection voltage value by each differential amplifier is included in the diagnostic information received from each cell controller. The microcomputer CPU affirms step S35 if the difference between the preliminarily stored reference voltage value Vo (here 3.75V) and the detected voltage value in the diagnostic information is less than 0.15V, for example. If the difference between the reference voltage value Vo and the detected voltage value in the diagnostic information is 0.15 V or more, a negative determination is made in step S35 and the process proceeds to step S40. In step S40, the microcomputer CPU sets an abnormality flag in the diagnosis result by the battery controller B / C and proceeds to step S45. The abnormality flag is stored in the RAM of the battery controller B / C corresponding to the cell controller diagnosed as abnormal.
[0024]
In step S45, the microcomputer CPU determines whether or not the diagnosis result by the cell controllers C / C1 to C / C5 is normal. When abnormality is diagnosed by each cell controller, the abnormality flag is included in the diagnostic information received from each cell controller. The microcomputer CPU makes an affirmative determination in step S45 when there is no abnormality flag in the diagnostic information from the cell controllers C / C1 to C / C5, that is, when the cell controller C / C1 to C / C5 determines that the abnormality is normal. The process proceeds to step S50, and if the abnormality information is included in the diagnostic information by the cell controllers C / C1 to C / C5, that is, if the abnormality is determined by the cell controllers C / C1 to C / C5, the determination in step S45 is negative. Then, the process proceeds to step S55.
[0025]
In step S50, the microcomputer CPU determines whether or not the diagnosis result by the battery controller B / C is normal. The diagnosis result by the battery controller B / C is determined by the presence or absence of an abnormality flag when a negative determination is made in step S35 described above. If the abnormality flag is not stored in the RAM, the microcomputer CPU makes an affirmative determination in step S50 and proceeds to step S65. If the abnormality flag is stored in the RAM, the microcomputer CPU makes a negative determination in step S50 and proceeds to step S60. In step S65, the microcomputer CPU determines that the diagnosis results by any of the cell controllers C / C1 to C / C5 and the battery controller B / C are normal, and proceeds to step S80 in FIG. In Step S60, which is determined to be negative in Step S50 and proceeds, the microcomputer CPU determines that there is a failure in the microcomputer CPU in the cell controllers C / C1 to C / C5, and proceeds to Step S80 in FIG.
[0026]
On the other hand, in step S55 which proceeds with a negative determination in step S45, the microcomputer CPU determines whether or not the diagnosis result by the battery controller B / C is normal. The microcomputer CPU makes an affirmative determination in step S55 when the abnormality flag is not stored in the RAM in the battery controller B / C, and proceeds to step S70. If the abnormality flag is stored in the RAM, the microcomputer CPU makes a negative determination. Then, the process proceeds to step S75. In step S70, the microcomputer CPU determines that there is an abnormality in communication between the battery controller B / C and the cell controllers C / C1 to C / C5, and proceeds to step S80 in FIG. In step S75, the microcomputer CPU determines that the voltage detection circuit has failed, and proceeds to step S80 in FIG.
[0027]
In step S80, the microcomputer CPU requests the cell controllers C / C1 to C / C5 to transmit the voltage detection value of each cell, and proceeds to step S85. In step S85, the microcomputer CPU determines whether or not the reception of the cell voltage value from the cell controllers C / C1 to C / C5 has been completed. When reception of the cell voltage value is completed, an affirmative determination is made in step S85 and the process proceeds to step S90. If reception of the cell voltage value is not completed, a negative determination is made in step S85 and the process returns to step S80.
[0028]
In step S90, the microcomputer CPU calculates the average value of the voltage value of each cell and proceeds to step S95. If a failure or abnormality is determined in any of Steps S60, S70, and S75 described above, the microcomputer CPU performs a fail-safe operation. That is, it is determined as normal without using the voltage value of the cell detected by the voltage detection circuit determined to be faulty or the voltage value transmitted from the cell controller determined to be faulty in the microcomputer CPU in the cell controller. The average value of the cell voltage value is calculated.
[0029]
In step S95, the microcomputer CPU calculates the cell voltage distribution, specifies a cell that seems to be abnormal from the calculated average value and distribution, and proceeds to step S100. In step S100, the microcomputer CPU determines whether or not it is necessary to adjust the capacity for each cell based on the cell voltage average value and the cell voltage distribution. The microcomputer CPU makes an affirmative determination in step S100 when the capacity adjustment for the cell is necessary, and proceeds to step S105. If the capacity adjustment is not necessary, the microcomputer CPU makes a negative determination in step S100 and proceeds to step S115.
[0030]
In step S105, the microcomputer CPU calculates the respective capacity adjustment times for the cells that require capacity adjustment, and proceeds to step S110. In step S110, the microcomputer CPU transmits a capacity adjustment time for each cell that requires capacity adjustment to each of the cell controllers C / C1 to C / C5, and proceeds to step S115. When capacity adjustment is unnecessary, a signal that does not require capacity adjustment is transmitted. In step S115, the microcomputer CPU requests the cell controllers C / C1 to C / C5 to transmit the voltage detection value of each cell, and proceeds to step S120. In step S120, the microcomputer CPU calculates the total voltage and the average value based on each received cell voltage value, and proceeds to step S125.
[0031]
In step S125, the microcomputer CPU calculates a battery capacity, a battery deterioration state, and the like for displaying a capacity of a capacity meter (not shown), and performs vehicle control of signals such as the calculated battery capacity and the battery deterioration state. The data is output to the illustrated controller and the like, and the process proceeds to step S130. In step S130, the microcomputer CPU determines whether or not the ignition switch is turned off. If the ignition switch is turned off, the determination in step S130 is affirmative and the process proceeds to step S135. If the ignition switch is not turned off, the determination in step S130 is negative and the process returns to step S115. In step S135, the microcomputer CPU transmits a power-off signal to the cell controllers C / C1 to C / C5 and proceeds to step S140. In step S140, the microcomputer CPU turns off the power supply of the battery controller B / C itself and ends the process of FIG.
[0032]
Next, processing performed by each microcomputer CPU of the cell controllers C / C1 to C / C5 will be described with reference to flowcharts. 5 and 6 are flowcharts for explaining the flow of processing performed by the microcomputer CPUs of the cell controllers C / C1 to C / C5, which are activated by an ON signal transmitted from the battery controller B / C. Here, one cell controller C / C1 will be described, but the same applies to other cell controllers. In step S500 of FIG. 5, the microcomputer CPU turns on the power based on the ON signal from the battery controller B / C and proceeds to step S510. In step S510, the microcomputer CPU initializes and proceeds to step S520. In step S520, the microcomputer CPU performs self-diagnosis and proceeds to step S530.
[0033]
In step S530, when the microcomputer CPU receives a signal for starting the failure diagnosis of the voltage detection circuit from the battery controller B / C, the microcomputer CPU turns on the capacity adjustment circuit switches SWb1 to SWb8, and turns on the cell reference voltage source switch SWc. Proceed to At this time, the cell voltage detection switches SWa1 to SWa8 are turned off. In step S540, the microcomputer CPU fetches the detection voltages Vd1 to Vd8 of the diagnostic cell reference voltage output from the differential amplifiers D1 to D8, and proceeds to step S550.
[0034]
In step S550, the microcomputer CPU determines whether or not the eight detected voltage values by the voltage detection circuit (differential amplifier) are normal. The microcomputer CPU affirms step S550 if the difference between the pre-stored reference voltage value Vo (here 3.75V) and the detected voltage value by the differential amplifier is less than 0.15V, for example. Determination is made and the process proceeds to step S560. If the difference between the reference voltage value Vo and the voltage detected by the differential amplifier is 0.15V or more, a negative determination is made in step S550 and the process proceeds to step S570. In step S560, the microcomputer CPU transmits the eight detected voltage values and the determination result (normal) to the battery controller B / C, and proceeds to step S580. On the other hand, in step S570, the microcomputer CPU sets an abnormality flag, transmits the eight detected voltage values, the determination result (abnormality), and the abnormality flag to the battery controller B / C, and proceeds to step S580. The abnormality flag is stored in the RAM of the cell controller corresponding to the cell diagnosed as abnormal.
[0035]
In step S580, the microcomputer CPU turns off the cell reference voltage source switch SWc and turns off the capacity adjustment circuit switches SWb1 to SWb8, and proceeds to step S590. In step S590, the microcomputer CPU turns on the cell voltage detection switches SWa1 to SWa8 and proceeds to step S600 in FIG. In step S600, the microcomputer CPU fetches the detection voltages Vd1 to Vd8 of the cells C1 to C8 output from the differential amplifiers D1 to D8, and proceeds to step S610. In step S610, upon receiving a cell detection voltage transmission request from the battery controller B / C, the microcomputer CPU transmits the detection voltages of the eight cells C1 to C8 to the battery controller B / C, and proceeds to step S620.
[0036]
In step S620, upon receiving the cell capacity adjustment time from the battery controller B / C, the microcomputer CPU turns on one of the capacity adjustment circuit switches SWb1 to SWb8 corresponding to the corresponding cell based on the received adjustment time. If a signal that does not require capacity adjustment is transmitted from the battery controller B / C, the process proceeds to step S630 without performing capacity adjustment. In step S630, the microcomputer CPU captures the detection voltages Vd1 to Vd8 of the cells C1 to C8 output from the differential amplifiers D1 to D8, and proceeds to step S640.
[0037]
In step S640, upon receiving a cell detection voltage transmission request from the battery controller B / C, the microcomputer CPU transmits the detection voltages of the eight cells C1 to C8 to the battery controller B / C, and proceeds to step S650. In step S650, when the microcomputer CPU receives the power-off signal from the battery controller B / C, the microcomputer CPU turns off the cell voltage detection switches SWa1 to SWa8, turns off the power of the cell controller, and ends the process of FIG.
[0038]
The embodiment described above will be summarized.
(1) When the cell voltage is detected by the cell controller C / C1, the cell voltage detection switches SWa1 to SWa8 between the cells C1 to C8 and the differential amplifiers D1 to D8 are turned on (step S590), and the differential amplifier D1 The terminal voltages Vc1 to Vc8 of the cells C1 to C8 are detected at .about.D8, respectively. Since the voltage of one cell is detected by one differential amplifier, the cost can be reduced as compared with the case of detecting by two differential amplifiers.
(2) At the time of failure diagnosis in the cell controller C / C1, the cell voltage detection switches SWa1 to SWa8 are turned off, and the cell reference voltage source switch SWc and the capacity adjustment circuit switches SWb1 to SWb8 are turned on (step S530). A voltage of 30 V output from the voltage unit Vs is applied to the capacity adjustment circuits E1 to E8. At this time, each of the differential amplifiers D1 to D8 detects a voltage of 30/8 = 3.75V (step S540), and when a voltage different from 3.75V by 0.15V or more is detected, the differential amplification is performed. The failure of the part is judged (step S550). Therefore, unlike the case where a voltage is detected by two differential amplification units and the failure of one of the two differential amplification units is determined when the two detected voltage values are different, a failure occurs in which differential amplification unit. You can see if
(3) At the time of failure diagnosis of (2) above, the voltage of 30V is divided using the capacity adjustment circuits E1 to E8, and the voltage of 3.75V after the voltage division is applied to each of the differential amplifiers D1 to D8. As a result, it is not necessary to add a new circuit for applying the reference voltage at the time of failure diagnosis. As a result, an increase in cost can be suppressed.
(4) The detection voltage value detected by each of the differential amplifiers D1 to D8 in (2) is transmitted from the cell controller C / C1 to the battery controller B / C via the communication interface circuit (steps S560 and S570). Whether or not the detected voltage value differs from 3.75V to 0.15V or more is determined also on the battery controller B / C side (step S35). Therefore, based on the determination result of the microcomputer CPU on the cell controller C / C1 side and the determination result of the microcomputer CPU on the battery controller B / C side, (1) normality is determined (step S65), and (2) the cell controller C / C1 (3) Judgment of abnormality in serial communication between cell controller C / C1 and battery controller B / C, (4) Judgment of failure of voltage detection circuit of cell controller C / C1 (step S60) Step S75), the cause of the failure can be isolated. As a result, it becomes easier to perform recovery work when a failure occurs.
(5) Since the cell voltage detection switches SWa1 to SWa8 are turned off when the power of the cell controller C / C1 is turned off, dark current does not flow from the cells C1 to C8 to the circuit for detecting the cell voltage. As a result, it is possible to suppress unnecessary power consumption and reduce the variation in capacity between cells caused by dark current.
[0039]
In the above description, an electric vehicle has been described as an example. However, the present invention can also be provided to a hybrid vehicle (HEV) equipped with an engine and a motor.
[0040]
The microcomputer CPU of the cell controller C / C1 and the microcomputer CPU of the battery controller B / C have a cell reference voltage for diagnosis with a difference of 0.15 V or more with respect to a reference voltage value Vo (3.75 V) given in advance. However, the voltage value described above may not be the value used in the description. That is, the reference voltage value Vo may be 5V, or 0.15V may be 1V. When the reference voltage value Vo is set to 5V, the voltage output from the diagnostic reference voltage unit Vs may be set to 40V.
[0041]
The correspondence between each component in the claims and each component in the embodiment of the invention will be described. The cells C1 to C40 are unit batteries, the differential amplifiers D1 to D8 are voltage detectors, the cell voltage The detection switches SWa1 to SWa8 are the first switch circuit, the diagnostic reference voltage unit Vs is the voltage generation circuit, the cell reference voltage source switch SWc is the second switch circuit, the overcharge is in the charged state, the cell controller C / The microcomputer CPUs C1 to C / C5 are the diagnosis device and the first diagnosis device, the capacity adjustment circuits E1 to E8 are the capacity adjustment circuit, the microcomputer CPU of the battery controller B / C is the second diagnosis device, and the communication interface circuit Corresponds to each communication circuit.
[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 performed by a microcomputer of the battery controller.
FIG. 4 is a flowchart illustrating a flow of processing performed by a microcomputer of the battery controller.
FIG. 5 is a flowchart for explaining the flow of processing performed by the microcomputer of the cell controller.
FIG. 6 is a flowchart for explaining the flow of processing performed by the microcomputer of the cell controller.
FIG. 7 is a block diagram of a conventional voltage detection circuit that detects the voltage of each cell.
[Explanation of symbols]
B / C ... battery controller, C1-C40 ... cell,
C / C1 to C / C5 ... cell controller,
CPU: microcomputer, D1 to D8: differential amplifier,
E1-E8 ... capacity adjustment circuit, M1-M5 ... module battery,
SWa1-SWa8 ... cell voltage detection switch,
SWb1 to SWb8 ... capacitance adjustment circuit switch,
SWc: Cell reference voltage source switch,
SWm ... Power switch, Vs ... Diagnostic reference voltage section

Claims (5)

In a vehicle that drives an assembled battery for an electric vehicle composed of a plurality of unit batteries as a power source
A voltage generation circuit for generating a predetermined voltage;
A voltage detection circuit that is provided for each unit battery and detects a voltage generated by the voltage generation circuit and a voltage of the unit battery;
When the voltage of the unit battery is detected by the voltage detection circuit, the state of charge of the unit battery is diagnosed according to the voltage detected by the voltage detection circuit, while the voltage detection circuit A voltage detection method for an assembled battery for an electric vehicle, comprising: a diagnosis device that diagnoses a failure of the voltage detection circuit according to a voltage detected by the voltage detection circuit when a generated voltage is detected apparatus. In a vehicle that drives an assembled battery for an electric vehicle composed of a plurality of unit batteries as a power source,
  A voltage generating circuit for generating a predetermined voltage;
  A voltage detection circuit that is provided for each unit battery and detects a voltage generated by the voltage generation circuit and a voltage of the unit battery;
  When the voltage of the unit battery is detected by the voltage detection circuit, the state of charge of the unit battery is diagnosed according to the voltage detected by the voltage detection circuit, while the voltage detection circuit A first diagnostic device that performs fault diagnosis of the voltage detection circuit according to the voltage detected by the voltage detection circuit when the generated voltage is detected;
  A second diagnostic device that performs a failure diagnosis of the voltage detection circuit and the first diagnostic device based on a voltage detected by the voltage detection circuit and a diagnosis result by the first diagnostic device. A voltage detection device for an assembled battery for an electric vehicle. In the voltage detection apparatus of the assembled battery for electric vehicles of Claim 2,
  A communication circuit for exchanging a detection voltage by the voltage detection circuit and a diagnosis result by the first diagnosis device between the first diagnosis device and the second diagnosis device;
  The voltage diagnostic device for an assembled battery for an electric vehicle, wherein the second diagnostic device further performs a failure diagnosis of the communication circuit based on the received detection voltage and a diagnosis result. In the voltage detection apparatus of the assembled battery for electric vehicles as described in any one of Claims 1-3,
  A first switch circuit for turning on / off the connection between the voltage detection circuit and the unit battery;
  A second switch circuit for turning on / off the connection between the voltage generation circuit and the voltage detection circuit;
  The voltage detection circuit detects the voltage of the unit battery connected to the unit battery when the first switch circuit is turned on and the second switch circuit is turned off, and the first switch A voltage of the assembled battery for an electric vehicle, wherein the voltage generated from the voltage generation circuit is detected by being connected to the voltage generation circuit when the circuit is turned off and the second switch circuit is turned on Detection device. In the voltage detection apparatus of the assembled battery for electric vehicles as described in any one of Claims 1-4,
  A capacity adjustment circuit that is provided for each unit battery and discharges the unit battery when the diagnostic device diagnoses that the capacity of the unit battery needs to be adjusted;
  The voltage detection apparatus for an assembled battery for an electric vehicle, wherein the voltage generated by the voltage generation circuit is applied to the voltage detection circuit via the capacity adjustment circuit.

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