JP2008139261A - Voltage-measuring device for battery pack - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enable measurement of the voltage of a secondary battery by a voltage-measuring part, of each secondary battery based on a command signal from a control device, and, moreover, to eliminate power consumption, when the voltage of the secondary battery is not measured. <P>SOLUTION: A voltage-measuring part 20 is connected to each secondary battery 11 of a battery pack, in which a plurality of secondary batteries 11 are connected in series. The voltage-measuring part 20 comprises a voltage-measuring means 21 for detecting the voltage of the secondary battery and converting the detected value into a digital signal; and a switching element 22 that is to be controlled for switching between an on-state to supply electric power from the secondary battery 11, to the voltage measuring means 21 and an off-state. The voltage-measuring part 20 also has a first photocoupler 24 that is to be controlled for on/off setting by the control device which outputs a voltage-measuring command to the voltage-measuring part 20, wherein the light receiving part 24a is connected in series to a control terminal of the switching element 22. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a so-called assembled battery voltage measuring device configured by connecting a plurality of secondary batteries in series, and more particularly to an assembled battery voltage measuring device for measuring the voltage of each secondary battery constituting the assembled battery. .

  A so-called main battery used in an electric vehicle or a hybrid vehicle is a so-called module battery composed of a combination of a plurality of unit cells connected in series to a battery whose required output voltage is 100 times or more the output voltage of a unit cell. An assembled battery is used. Hereinafter, the module battery may be simply referred to as a module. For example, when a nickel-hydrogen battery is used as a power source for an electric vehicle or a hybrid vehicle, unit cells (cells) having an output voltage of about 1.2 V are connected in series to form one module, and 24 modules are connected in series. Connected to the battery, the battery pack is composed of a total of 240 cells of nickel-hydrogen batteries, and a total voltage of 288V is obtained. In the assembled battery, not all the batteries constituting the assembled battery have uniform characteristics, and there is a possibility that the performance partially deteriorates due to aging. Therefore, in order to monitor the state of the assembled battery, the voltage of each module constituting the assembled battery is measured.

  Conventionally, an assembled battery monitoring device capable of avoiding problems caused by directly taking a high voltage to be measured into a vehicle and monitoring the voltage of each module has been proposed. For example, see Patent Document 1). As shown in FIG. 6, in this monitoring apparatus, a voltage monitoring unit is connected in parallel for each module (battery) 61 constituting the assembled battery 60, and one voltage monitoring unit is a master unit 62, and the other The voltage monitoring unit is a slave unit 63. Each of the master unit 62 and the slave unit 63 inputs the terminal voltage of the corresponding module 61 as a signal under measurement (measurement signal), and also obtains the power supply of the voltage monitoring unit itself from the terminal voltage. The master unit 62 is connected to an electronic control unit (ECU) 65 via a serial communication line 64. The master unit 62, the slave unit 63, and the slave units 63 are connected to each other via a serial communication line 66.

  The master unit 62 includes a CPU, a serial communication terminal S1 for the serial communication line 66, and a serial communication terminal S2 for the serial communication line 64, and the slave unit 63 includes a serial communication terminal S1 for the CPU and the serial communication line 66. ing. The input port and output port of the CPU are each connected to the serial communication terminal S1 via a photocoupler, and the CPU of the master unit 62 communicates with another input port and output port via a photocoupler. It is connected to the terminal S2.

The master unit 62 is configured to receive the voltage measurement command signal directly from the external electronic control unit 65 and measure the voltage, and to output the voltage measurement command signal to the slave unit 63. The slave unit 63 receives the voltage measurement command signal from the master unit 62 and performs voltage measurement. The master unit 62 and the slave unit 63 are configured to alternately repeat a voltage measurement mode for measuring voltage and a sleep mode with low power consumption. The sleep mode means a state in which power supply to other than the CPU is turned off to reduce power consumption and wait for a voltage measurement command signal.
JP-A-8-140204

  In the prior art, the voltage monitoring units (master unit 62 and slave unit 63) measure the voltage of each module based on the voltage measurement command signal, and stand by in the sleep mode (sleep state) when not measuring. Therefore, even in a state where voltage measurement is not performed, although it is in a sleep state, dark current flows through the regulator that keeps the CPU and CPU at a constant voltage (standby power is consumed). There is a problem of getting faster.

  Further, in the prior art, a communication line is required for transmitting a voltage measurement command signal to each voltage monitoring unit and for transmitting a voltage measured by each voltage monitoring unit to an external control device (electronic control unit 65). And

  The present invention has been made in view of the above-described conventional problems, and an object of the present invention is to enable the voltage measuring unit of each secondary battery to measure the voltage of the secondary battery based on a command signal from the control device. And it is providing the voltage measuring apparatus of the assembled battery which can eliminate the power consumption at the time of the non-measurement of the voltage of a secondary battery.

  In order to achieve the above object, an invention according to claim 1 is a set including voltage measuring units each connected to each of the secondary batteries of a battery pack configured by connecting a plurality of secondary batteries in series. This is a battery voltage measuring device. The voltage measuring unit detects a voltage of the secondary battery and converts the detected value into a digital signal, and does not supply a state in which power is supplied from the secondary battery to the voltage measuring means. A switching element that is controlled to be switched to a state, a photocoupler in which a light receiving unit is connected in series with a control terminal of the switching element, and a light emitting unit is connected to a control device that outputs a voltage measurement command to the voltage measuring unit; It has.

  In this invention, the voltage measuring unit provided for each secondary battery of the assembled battery can measure the voltage of the secondary battery in a state where power is supplied from the secondary battery when the switching element is turned on. It becomes possible. The switching element is turned on when the light receiving unit of the photocoupler that emits light is turned on when a voltage measurement command is output from the control device to the light emitting unit, and turned off when the light receiving unit of the photocoupler is turned off. Therefore, when the voltage measurement command is output from the control device even when the power (power supply) is supplied from the secondary battery and the sleep state is not maintained in a state where the voltage measurement command is not output from the control device. Based on the signal, voltage measurement can be performed. In addition, since it is not necessary to maintain the sleep state, it is possible to eliminate power consumption when the voltage of the secondary battery is not measured.

  According to a second aspect of the present invention, in the first aspect of the present invention, the photocoupler is a measurement in which the control device instructs the voltage measurement unit to output measurement data measured by the voltage measurement unit. Also used as a data output command section. In this invention, since the photocoupler that controls on / off of the switching element as a switch for supplying power from the power source, that is, the secondary battery to the voltage measurement unit, is also used as the measurement data output command unit from the control device, Compared to a configuration in which a measurement data output command unit is provided separately, the configuration is simplified.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, the voltage measuring unit is turned on and off by a microcomputer in which the light emitting unit constitutes the voltage measuring unit in addition to the photocoupler. While being controlled, the light receiving unit includes a second photocoupler connected in parallel with the light emitting unit of the photocoupler. In each of the voltage measuring units, the photocoupler and the second photocoupler are connected by a single signal line. In this invention, while the light measuring unit of the photocoupler of all the voltage measuring units is held in the ON state by a command from the control device, the voltage measuring unit outputs the ON signal to the second photocoupler. No current flows through the light emitting part of the photocoupler connected in parallel with the light receiving part. Therefore, the microcomputer constituting the voltage measuring means of any one of the voltage control units performs on / off control corresponding to the data to be transmitted to the second photocoupler, and the total voltage change of all the voltage measuring units in the control device By detecting this, the data output from the measurement unit equipped with the voltage measurement means can be confirmed by the control device. As a result, a signal line for transmitting a command signal from the control device to the voltage measurement unit of each secondary battery and a signal line for the control device to obtain measurement voltage data of each secondary battery of the voltage measurement unit are shared. This reduces the number of wires connecting the control device and each voltage measuring unit.

  According to the present invention, the voltage measuring unit of each secondary battery can measure the voltage of the secondary battery based on the command signal from the control device, and power consumption when the voltage of the secondary battery is not measured is eliminated. be able to.

(First embodiment)
Hereinafter, an embodiment in which the present invention is embodied in an assembled battery voltage measuring device as a main battery mounted on an electric vehicle will be described with reference to FIGS. 1 and 2.

  As shown in FIG. 2, the assembled battery 10 as a main battery is configured by connecting a plurality (for example, 24) of secondary batteries 11 in series. The secondary battery is a single battery or a module battery. A module battery is a battery in which a required number of unit cells are joined to form a single module. Each secondary battery 11 is constituted by a series connection body of a plurality of (for example, 10) cells. The assembled battery 10 is connected to an inverter 12 that drives and controls a travel motor (not shown) via a contactor 13. A voltage measuring unit 20 is connected to the assembled battery 10 for each secondary battery 11.

  As shown in FIG. 1, the voltage measuring unit 20 detects the voltage of the secondary battery 11 and converts the detected value into a digital signal, and supplies the power of the secondary battery 11 to the voltage measuring means 21. A switching element 22 is provided as a switch that is controlled to be switched between a supply state and a non-supply state. The switching element 22 is composed of a PNP transistor, and has an emitter connected to the plus terminal of the secondary battery 11 and a collector connected to the plus side input part of the voltage measuring means 21. A switch breaking resistor 23 is connected between the emitter of the switching element 22 and the base as a control terminal. The base of the switching element 22 is connected in series to the light receiving unit 24 a of the first photocoupler 24 provided in the voltage measuring unit 20 via a resistor 25.

  Voltage-dividing resistors 26 and 27 are connected between the collector of the switching element 22 and the negative terminal of the secondary battery 11, and the connection point between the collector of the switching element 22 and the voltage-dividing resistor 26 is connected to two points. An electrolytic capacitor 28 is connected between the negative terminal of the secondary battery 11. The voltage measuring means 21 includes a microcomputer 29 and a power supply regulator 30, and the microcomputer 29 is supplied with power from the power supply regulator 30.

  The microcomputer 29 inputs the voltage at the connection point of the voltage dividing resistors 26 and 27 and the output voltage of the reference voltage generation circuit 31, and converts the voltage of the secondary battery 11 into a digital value by an A / D converter (not shown). Temporarily store in memory. The microcomputer 29 is connected to the light receiving unit 24 a of the first photocoupler 24 via a diode 32. The microcomputer 29 is connected to the anode of the diode 32.

  In the voltage measuring unit 20, in addition to the first photocoupler 24, the light emitting unit 33 a is ON / OFF controlled by the microcomputer 29, and the light receiving unit 33 b is connected in parallel with the light emitting unit 24 b of the first photocoupler 24. The second photocoupler 33 is provided.

  Different ID numbers are set for the respective voltage measuring units 20. When the microcomputer 29 of each voltage measuring unit 20 detects that the light emitting unit 24b of the first photocoupler 24 blinks in the on / off state corresponding to the pulse signal indicating its own ID number, the measured secondary battery 11 is measured. The light emitting unit 33a is driven and controlled to output a digital signal corresponding to the voltage data.

  As shown in FIG. 1, each voltage measuring unit 20 is connected by one signal line 34 to which the first photocoupler 24 and the second photocoupler 33 are connected. The light emitting unit 24b of the first photocoupler 24 of each voltage measuring unit 20 is connected in series, and one end of the light emitting unit 24b connected in series outputs a voltage measurement command to each voltage measuring unit 20. It is connected to the device 35.

  The control device 35 includes a microcomputer 36, a DC / DC converter 37, a constant current generation circuit 38 and a comparator 39. The output terminal of the constant current generating circuit 38 is connected to the plus side input terminal of the voltage measuring unit 20 on one end side via the signal line 34. The negative output terminal of the voltage measuring unit 20 on the other end side is grounded. The output terminal of the constant current generating circuit 38 is connected to the inverting input terminal of the comparator 39 and the microcomputer 36. A reference voltage is input to the non-inverting input terminal of the comparator 39. The reference voltage includes the voltage value output from the constant current generation circuit 38 when all the first photocouplers 24 are on, and the constant current generation circuit 38 when one first photocoupler 24 is off. Is set to an intermediate value with the voltage value output from the.

  The control device 35 uses a 12V auxiliary battery (not shown) as a power source, and the DC / DC converter 37 supplies a voltage capable of simultaneously driving the first photocoupler 24 connected in series with a 12V voltage, that is, the light emitting unit 24b. The voltage can be boosted to a voltage equal to or higher than the product of the forward voltage of the photodiode to be configured and the number of first photocouplers 24. The voltage boosted by the DC / DC converter 37 is output from the constant current generating circuit 38 in accordance with a control signal from the microcomputer 36.

  When obtaining voltage data of each secondary battery 11 from each voltage measuring unit 20, the microcomputer 36 outputs a voltage necessary for turning on all the first photocouplers 24 from the constant current generation circuit 38. Then, a measurement data transmission command is output to each voltage measurement unit 20. Specifically, a pulse signal corresponding to the ID number of each voltage measurement unit 20 is sequentially output from the constant current generation circuit 38. The microcomputer 36 outputs a pulse signal corresponding to the ID number to one voltage measuring unit 20, and then inputs a change in the output signal of the comparator 39, and the voltage from the voltage measuring unit 20 corresponding to the ID number. Check the data.

Next, the operation of the voltage measuring apparatus configured as described above will be described.
The microcomputer 36 of the control device 35 obtains the voltage data of each secondary battery 11 from each voltage measurement unit 20 at a predetermined cycle, and monitors the state of the assembled battery 10. The microcomputer 36 obtains voltage data of each voltage measuring unit 20 according to the flowchart of FIG. In step S <b> 1, the microcomputer 36 outputs a constant current signal for lighting the light emitting parts 24 b of all the first photocouplers 24 from the constant current generation circuit 38.

  After a predetermined time has elapsed, in step S2, the microcomputer 36 sequentially outputs an ID number to each voltage measurement unit 20 and obtains voltage data from each voltage measurement unit. The predetermined time is, for example, the time required for each voltage measuring unit 20 to complete voltage measurement of the secondary battery 11 after the light emitting unit 24b is turned on. The output of the ID number means that the constant current generation circuit 38 is controlled to be turned on / off so that the constant current generation circuit 38 outputs a pulse signal corresponding to the ID number.

  Obtaining voltage data from the voltage measuring unit means obtaining voltage data from a change in the output state of the comparator 39, that is, a change in L level and H level. More specifically, the comparator 39 compares the output voltage of the constant current generation circuit 38 with a reference voltage, and outputs an H level signal when the output voltage of the constant current generation circuit 38 is greater than the reference voltage. When the output voltage of the generation circuit 38 is smaller than the reference voltage, an L level signal is output. Then, the output voltage of the constant current generation circuit 38 is a voltage corresponding to the sum of the forward voltages of the light emitting units 24b of all the first photocouplers 24 if the second photocoupler 33 is in an off state. However, when the microcomputer 29 of the voltage measuring unit 20 controls on / off of the second photocoupler 33 for voltage data transmission, the light emitting unit 33a blinks. When the light emitting unit 33a emits light (lights) and a current flows through the light receiving unit 33b, no current flows through the light emitting unit 24b connected in parallel with the light receiving unit 33b, and the constant current generating circuit 38 The output voltage decreases accordingly. Therefore, the output of the comparator 39 changes between the L level and the H level so as to become a pulse signal corresponding to the voltage data transmitted by the microcomputer 29 of the voltage measuring unit 20. As a result, the microcomputer 36 can obtain voltage data from the output change of the comparator 39.

  Next, in step S3, the microcomputer 36 determines whether or not the acquisition of voltage data from all the voltage measuring units 20 has been completed. If not, the process returns to step S2. If completed, the process proceeds to step S4. After stopping the output of the constant current signal from the constant current generating circuit 38, the process is terminated.

  On the other hand, each voltage measuring unit 20 receives power supply from the secondary battery 11 with the switching element 22 turned on. However, when the switching element 22 is turned off, the power supply from the secondary battery 11 is stopped. Even if the power supply from the secondary battery 11 is stopped, the voltage measuring unit 20 can be operated for a while by the power charged in the electrolytic capacitor 28 when the switching element 22 is in the ON state.

  Since the control device 35 obtains the voltage data of the secondary battery 11 from each voltage measuring unit 20, when a constant current signal is output from the constant current generating circuit 38 and the first photocoupler 24 is turned on, the light receiving unit 24a. Is turned on, and the switching element 22 is turned on. When the switching element 22 is turned on, power is supplied to the microcomputer 29 through the power supply regulator 30, and the microcomputer 29 starts to operate, and performs voltage measurement and transmission of the measured voltage data according to the flowchart shown in FIG. Do.

  First, the microcomputer 29 measures the voltage of the secondary battery 11 in step S21. In the voltage measurement, a voltage divided by the voltage dividing resistors 26 and 27 is input, the voltage is changed to a digital value, and then the voltage of the secondary battery 11 is calculated and stored in the memory. Next, the microcomputer 29 determines whether or not its own ID number is output from the control device 35 in step S22. Specifically, it is determined whether or not the light emitting unit 24b blinks at a pulse having an interval corresponding to its own ID number. When the first photocoupler 24 is turned on, an L level signal is input to the port P connected to the diode 32. Therefore, the microcomputer 29 sets its own ID at the interval of the L level signal. Judgment is made as to whether or not blinking occurs at a pulse interval corresponding to the number. The diode 32 serves to prevent the voltage of the secondary battery 11 from being applied to the port P of the microcomputer 29 via the switch cutoff resistor 23 and the resistor 25 when the first photocoupler 24 is off. .

  Since the control device 35 sequentially outputs a pulse signal having an interval corresponding to the ID number to each voltage measuring unit 20, the first photocoupler 24 of each voltage measuring unit 20 blinks during that time, but the microcomputer 29 is self- If it is not blinking at an interval corresponding to the ID number, it waits. If it is determined that its own ID number has been output, the process proceeds to step S23, and voltage data is output in step S23. Specifically, after the second photocoupler 33 is on / off controlled with a pulse signal obtained by binarizing the voltage data, the process is terminated.

  In the standby state of the microcomputer 29, the first photocoupler 24 repeatedly blinks, and the switching element 22 also repeats the on / off operation accordingly, so that the power supply from the secondary battery 11 via the switching element 22 is also intermittent. Become. However, since the electrolytic capacitor 28 exists, the microcomputer 29 operates without any trouble.

According to this embodiment, the following effects can be obtained.
(1) The voltage measuring unit 20 connected to each secondary battery 11 of the assembled battery 10 detects the voltage of the secondary battery 11 and converts the detected value into a digital signal, and voltage measurement A switching element 22 that is controlled to be switched between a state in which power is supplied from the secondary battery 11 to the means 21 and a state in which power is not supplied to the means 21, and a first photocoupler 24 are provided. In the first photocoupler 24, the light receiving unit 24 a is connected in series with the control terminal of the switching element 22, and the light emitting unit 24 b is connected to a control device 35 that outputs a voltage measurement command to the voltage measuring unit 20. Therefore, in the state where the voltage measurement command is not output from the control device 35, the voltage measurement command is output from the control device 35 even when the power (power supply) is supplied from the secondary battery 11 and the sleep state is not maintained. Then, the voltage can be measured based on the signal. Further, since it is not necessary to maintain the sleep state, power consumption when the voltage of the secondary battery 11 is not measured can be eliminated.

  (2) The first photocoupler 24 that performs on / off control of the switching element 22 serving as a switch for supplying power from the power source, that is, the secondary battery 11 to the voltage measurement unit 20, the control device 35 is connected to the voltage measurement unit 20. On the other hand, it is also used as a measurement data output command section that issues an output command of measurement data measured by the voltage measuring means 21. Therefore, the number of signal lines and the like is reduced and the configuration is simplified as compared with the configuration in which the measurement data output command unit is provided separately.

  (3) In the voltage measuring unit 20, in addition to the first photocoupler 24, the light emitting unit 33a is on / off controlled by the microcomputer 29 constituting the voltage measuring unit 21, and the light receiving unit 33b is controlled by the first photocoupler. A second photocoupler 33 connected in parallel with the 24 light emitting units 24b is provided. In each voltage measuring unit 20, the first photocoupler 24 and the second photocoupler 33 are connected by a single signal line 34. Therefore, in the state where the microcomputer 29 of any one of the voltage measuring units 20 performs on / off control corresponding to the data to be transmitted from the second photocoupler 33, the control device 35 changes the total voltage of all the voltage measuring units 20. By detecting this, the data output from the voltage measurement unit 20 provided with the voltage measurement means 21 can be confirmed by the control device 35. As a result, the control device 35 obtains a signal line for transmitting a command signal from the control device 35 to the voltage measurement unit 20 of each secondary battery 11 and measurement voltage data of each secondary battery 11 of the voltage measurement unit 20. These signal lines can be shared, and the number of wires connecting the control device 35 and each voltage measuring unit 20 is reduced.

  (4) An electrolytic capacitor 28 is connected to the switching element 22 in parallel with the voltage measuring means 21. Therefore, once the switching element 22 is turned on, the supply voltage to the voltage measuring means 21 is kept stable even if the first photocoupler 24 is subsequently turned on / off.

  (5) When the second photocoupler 33 is controlled to be turned on / off so that the voltage measurement unit 20 transmits voltage data, the voltage measurement unit 20 is provided in the voltage measurement unit 20 when the second photocoupler 33 is on. The first photocoupler 24 is turned off. However, since the light emitting unit 24b of the first photocoupler 24 and the light receiving unit 33b of the second photocoupler 33 are connected in parallel, the first photocoupler of the voltage measuring unit 20 that is not transmitting voltage data. 24 is supplied with power from the secondary battery 11 since the other voltage measuring unit 20 is kept on even during transmission and the switching element 22 is also kept on.

  (6) The control device 35 includes a DC / DC converter 37 as a step-up converter, generates a voltage equal to or higher than the product of the total number of secondary batteries 11 and the forward voltage of the first photocoupler 24, and has a constant current. The signal is output to the signal line 34 via the generation circuit 38. Therefore, even if the voltage of the power source of the control device 35 is lower than the total voltage of all the forward voltages of the first photocoupler 24, the first photocouplers 24 of all the voltage measuring units 20 are simultaneously turned on without any trouble. It becomes possible to hold.

  (7) Since the assembled battery 10 is a main battery used as a drive source for a travel motor of an electric vehicle, the voltage of each secondary battery 11 of the main battery of the electric vehicle can be reliably monitored when necessary. Battery life can be extended.

The embodiment is not limited to the above, and may be embodied as follows, for example.
The voltage of the power source that supplies power to the control device 35 is lower than the voltage value necessary to simultaneously hold the first photocoupler 24 corresponding to the number of secondary batteries 11 constituting the assembled battery 10 in the on state. In this case, instead of providing the control device 35 with the DC / DC converter 37, the secondary batteries 11 are divided into a plurality of groups. Then, a control device 35 may be provided for each group, and the control device 35 and the first photocoupler 24 and the second photocoupler 33 of each voltage measurement unit 20 may be connected in the same configuration as in the above embodiment. In this case, it is preferable to make the number of secondary batteries 11 constituting each group the same.

  The first photocoupler 24 does not have to be used as a measurement data output command unit in which the control device 35 instructs the voltage measurement unit 20 to output measurement data measured by the voltage measurement unit 21. For example, a photocoupler for measuring data output command is provided in each voltage measuring unit 20. The photocouplers may be connected in series, and each photocoupler may be controlled to be turned on / off by the control device 35 while the first photocoupler 24 is kept on. In this case, the switching element 22 can be kept on until each voltage measuring unit 20 completes transmission of voltage data without providing the electrolytic capacitor 28 in each voltage measuring unit 20.

  The transmission command of the voltage data measured by each voltage measuring unit 20 to the control device 35 is not limited to the configuration in which the ID number is transmitted from the control device 35 to each voltage measuring unit 20. For example, each voltage measuring unit 20 is configured such that the microcomputer 29 transmits voltage data after a predetermined time after the first photocoupler 24 is turned on, and the length of the predetermined time is set for each voltage measuring unit 20. You may make it set so that it may differ. The microcomputer 36 of the control device 35 turns on the first photocoupler 24 and then obtains voltage data transmitted from each voltage measuring unit 20 every predetermined time without transmitting an ID number. The voltage data of each voltage measuring unit 20 can be obtained. In this case, turning on the first photocoupler 24 also serves as a command for transmitting voltage data measured by each voltage measuring unit 20 to the control device 35.

  Each voltage measuring unit 20 can eliminate power consumption when the voltage of the secondary battery 11 is not measured, and the control device 35 and each voltage measuring unit 20 are insulated from the control device 35. Any configuration that can perform voltage measurement based on a signal when a voltage measurement command is output may be used. Therefore, the switching element 22 that is controlled to be switched between the state in which power is supplied from the secondary battery 11 to the voltage measuring means 21 and the state in which the power is not supplied, and the light receiving unit 24a are connected in series with the control terminal of the switching element 22, and the light emitting unit What is necessary is just to provide 24b with the 1st photocoupler 24 connected to the control apparatus 35 which outputs a voltage measurement instruction | command to the voltage measurement part 20. FIG. That is, it is not necessary to include the light emitting unit 33 a that is controlled to be turned on / off by the microcomputer 29 and the second photo coupler 33 in which the light receiving unit 33 b is connected in parallel with the light emitting unit 24 b of the first photo coupler 24. For example, a communication line for transmitting voltage data from each voltage measuring unit 20 may be provided between the control device 35 and each voltage measuring unit 20 instead of the second photocoupler 33. Specifically, as shown in FIG. 5, the light emitting portions 24b of the first photocoupler 24 are connected in series. Each voltage measurement unit 20 includes a serial interface 41 connected to the serial communication line 40 instead of the second photocoupler 33. The control device 35 includes a serial interface 42 connected to the serial communication line 40. The microcomputer 29 of each voltage measuring unit 20 transmits voltage data via the serial interface 41, and the microcomputer 36 of the control device 35 obtains voltage data via the serial interface 42. The serial communication line 40 may be configured to allow mutual communication, or may be dedicated to transmission from the voltage measurement unit 20 side.

  In this case, each voltage measurement unit 20 transmits a voltage data signal after the first photocoupler 24 is turned on and after a predetermined time set with a different value for each voltage measurement unit 20 has elapsed. Then, the control device 35 does not need to issue a data transmission command to each voltage measurement unit 20. Therefore, even if the serial communication line 40 is dedicated to transmission from the voltage measurement unit 20 side, the control device 35 needs to inform each voltage measurement unit 20 of the ID number by the on / off control of the first photocoupler 24. Instead, the first photocoupler 24 is kept on until the transmission of the voltage data from each voltage measuring unit 20 is completed. Therefore, the electrolytic capacitor 28 can be omitted.

(Circle) you may change suitably the number of the secondary batteries 11 which comprise the assembled battery 10, and the number of the single cells (cell) which comprise the module battery as the secondary battery 11. FIG.
The assembled battery 10 is not limited to a nickel metal hydride battery, and may be a lithium ion battery or a sealed lead battery.

The assembled battery 10 is not limited to an electric vehicle, and may be a main battery used as a drive source for a travel motor of a hybrid vehicle or a battery used outside a vehicle.
Next, the technical idea (invention) that can be grasped from the above embodiment and other examples will be described below together with their effects.

  (A) In the invention according to claim 1, a capacitor is connected in parallel with the voltage measuring means with respect to the switching element. According to the invention described in (a), once the switching element is turned on, the supply voltage to the voltage measuring means is maintained in a stable state even if the photocoupler is subsequently turned on / off.

  (B) In the invention according to claim 3, the control device includes a step-up converter, generates a voltage equal to or higher than the product of the total number of the secondary batteries and the forward voltage of the photocoupler, and includes a constant current circuit. To the signal line. In the present invention, even if the voltage of the power supply of the control device is lower than the total voltage of all the forward voltages of the photocoupler, it is possible to simultaneously hold the photocouplers of all the voltage measuring units in the on state without any trouble.

  (C) An assembled battery voltage measuring device including a voltage measuring unit connected to each of the secondary batteries of the assembled battery configured by connecting a plurality of secondary batteries in series, the voltage measuring unit The voltage measuring means for detecting the voltage of the secondary battery and converting the detected value into a digital signal, the light receiving section is connected to the microcomputer constituting the voltage measuring means, and the light emitting section is connected to each voltage measuring section The first photocoupler connected to the control device that outputs a voltage measurement command to the light source and the light emitting unit are controlled to be turned on / off by a microcomputer constituting the voltage measuring means, and the light receiving unit emits light from the first photocoupler. A battery pack voltage measuring apparatus comprising: a second photocoupler connected in parallel with the unit. According to the invention described in (c), the control device transmits a signal line for transmitting a command signal from the control device to the voltage measurement unit of each secondary battery, and measurement voltage data of each secondary battery of the voltage measurement unit. The signal line for obtaining can be shared.

  (D) In the invention according to any one of claims 1 to 3 and the technical ideas (a) to (c), the assembled battery is used as a drive source of a travel motor of an electric vehicle or a hybrid vehicle. Main battery. According to the invention described in (d), voltage monitoring of each secondary battery of the main battery of the electric vehicle can be reliably performed when necessary, and the life of the main battery can be extended.

The circuit diagram of the voltage measurement part of each secondary battery in one embodiment. The circuit diagram which shows the structure of the whole voltage measuring device. The flowchart which shows the process sequence of the microcomputer of a control apparatus. The flowchart which shows the process sequence of the microcomputer of a voltage measurement part. The partial circuit diagram of the voltage measuring device in another embodiment. The circuit diagram which shows the structure of the voltage monitoring apparatus of a prior art.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 ... Assembly battery, 11 ... Secondary battery, 20 ... Voltage measurement part, 21 ... Voltage measurement means, 22 ... Switching element, 24 ... 1st photocoupler as a photocoupler, 24a, 33b ... Light-receiving part, 24b, 33a ... Light emitting unit, 29, 36... Microcomputer, 33... Second photocoupler, 34.

Claims (3)

An assembled battery voltage measuring device including a voltage measuring unit connected to each of the secondary batteries of the assembled battery configured by connecting a plurality of secondary batteries in series,
The voltage measuring unit detects voltage of the secondary battery and converts the detected value into a digital signal; and
A switching element that is controlled to switch between supplying and not supplying power from the secondary battery to the voltage measuring means;
A battery pack comprising: a photocoupler connected in series with a control terminal of the switching element; and a light coupler connected to a control device that outputs a voltage measurement command to the voltage measurement unit. Voltage measuring device.   2. The assembled battery according to claim 1, wherein the photocoupler is also used as a measurement data output command unit that instructs the voltage measurement unit to output measurement data measured by the voltage measurement unit to the voltage measurement unit. Voltage measuring device.   In the voltage measuring unit, in addition to the photocoupler, a light emitting unit is controlled to be turned on / off by a microcomputer constituting the voltage measuring unit, and a light receiving unit is connected in parallel with the light emitting unit of the photocoupler. The set according to claim 1 or 2, wherein each of the voltage measuring units is connected by one signal line to which the photocoupler and the second photocoupler are connected. Battery voltage measuring device.

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