JP5880232B2 - Remaining amount detection unit - Google Patents

Description

  The present invention relates to a remaining amount detection unit suitable for detecting the remaining amount of a secondary battery mounted on an electric vehicle such as an electric vehicle or a hybrid vehicle.

  Patent Document 1 discloses a technique for switching between a voltage method and a current integration method in accordance with a comparison result between a current battery current value and a threshold value when detecting the remaining amount of a secondary battery.

Japanese Patent No. 4210794

  An electric vehicle such as an electric vehicle or a hybrid vehicle can be charged by an external power source outside the vehicle, and the charging mode is a so-called “normal charging mode” in which charging is performed with a small power capacity using an AC100V or AC200V outlet. There is a so-called “rapid charging mode” in which charging is performed in a short time with a large power capacity.

  According to the technique of Patent Document 1, the change of the charging mode is not taken into consideration. For example, the voltage method is adopted even when the battery voltage fluctuation is prolonged, and the accuracy of the remaining amount detection may be deteriorated. It was.

  An object of the present invention is to make it possible to detect the remaining amount of a battery with higher accuracy than in the past.

According to a first aspect of the present invention, there is provided a remaining amount detection unit including a voltage detection unit that detects a voltage value of a battery, a current detection unit that detects a current value of the battery, and a voltage value detected by the voltage detection unit. A first determination unit that determines the remaining amount of the battery based on the second determination unit, a second determination unit that determines the remaining amount of the battery based on an integrated value of the current value detected by the current detection unit; comprising a charging mode determining means for determining a charging mode, and selection means for selecting one of said charging mode determining means determines based on the result from the first determination means and the second judging means The charging mode has at least two types of charging modes having different supply power capacities, and the selection means is a predetermined time after the charge mode determination means determines the end of the quick charge mode with a large supply power capacity. Progress Said first determination means select the charging mode determining means, when it is determined the rapid charging mode, and selects the second determining means.

  According to the present invention, it is possible to detect the remaining battery level with higher accuracy than in the past.

The figure which shows the structure of an electric vehicle. The block diagram of the residual amount detection unit in FIG. The flowchart of CPU in FIG. The figure which shows an example of the change of the electric current value of battery current, and the change of the residual amount detection method to be used.

  An embodiment of the present invention will be described with reference to the drawings. In addition, this embodiment shall be related with the electric vehicle 100 as an example of an electric vehicle.

  FIG. 1 is a diagram showing a configuration of the electric vehicle 100. The electric vehicle 100 includes a number of elements similar to those of another existing electric vehicle, but FIG. 1 shows only some of these elements.

  The electric vehicle 100 includes a main body 1, front wheels 2, rear wheels 3, a motor 4, a speed reducer 5, a battery 6, an inverter 7, a power supply line 8, contactors 9, 10, a fuse 11, a charging plug 12, and an ECU (electric control unit). 13 and a remaining amount detection unit 14.

  The main body 1 includes a chassis and a vehicle body, supports other elements, and forms a space for an occupant to board.

  The front wheel 2 has two arranged in the depth direction in FIG. 1 and is rotatably supported by the main body 1.

  The rear wheel 3 has two arranged in the depth direction in FIG. 1 and is rotatably supported by the main body 1.

  The front wheel 2 and the rear wheel 3 are grounded in the normal use state of the electric vehicle 100 to support the main body 1 and rotate to move the main body 1.

  The motor 4 operates with AC power supplied from the inverter 7 and rotates the output shaft.

  The speed reducer 5 is connected to the output shaft of the motor 4, and the rotation of the output shaft is decelerated and transmitted to the rear wheel 3.

  The battery 6 includes a large number of battery cells 6a connected in series. The battery 6 generates a high-voltage DC voltage. The battery 6 can be charged by supplying power from the outside. That is, the battery 6 is a secondary battery.

  The inverter 7 converts a DC voltage generated by the battery 6 into an AC voltage. The inverter 7 supplies AC power to the motor 4 by applying an AC voltage to the motor 4. The inverter 7 can change the voltage value of the generated AC voltage under the control of the ECU 13.

  The feed line 8 applies a DC voltage generated by the battery 6 to the inverter 7.

  The contactor 9 is interposed between the positive electrode of the battery 6 and the feeder line 8. The contactor 9 turns on / off the electrical connection between the positive electrode of the battery 6 and the feeder line 8 under the control of the ECU 13.

  The contactor 10 is interposed between the negative electrode of the battery 6 and the power supply line 8. The contactor 10 turns on / off the electrical connection between the negative electrode of the battery 6 and the feeder line 8 under the control of the ECU 13.

  The fuse 11 is interposed between the two battery cells 6a. The fuse 11 is blown by an excessive current exceeding the rating, and interrupts the power supply from the battery 6 to the inverter 7.

  The charging plug 12 is inserted between the two battery cells 6a, and a charging cable (not shown) for receiving power supply from an external power source (not shown) can be connected as necessary. The charging plug 12 connects the two battery cells 6a in series when the charging cable is not connected, and supplies the battery 6 with power supplied through the charging cable when the charging cable is connected.

  In FIG. 1, only one charging plug 12 is shown, and it is assumed that it corresponds to a plurality of charging modes such as a normal charging mode and a quick charging mode, but a plurality of charging plugs corresponding to each charging mode are provided. May be.

  Further, the position of the charging plug 12 is not limited to being inserted between the two battery cells 6a. The charging plug 12 and the battery cell 6a are connected via an in-vehicle charger to charge the power supply from the external power source. You may change within the range of a well-known technique so that it may receive via a cable.

  The ECU 13 controls the operation of some control target elements such as the inverter 7 and the contactors 9 and 10.

  The remaining amount detection unit 14 is connected to the battery 6 in parallel with the inverter 7. The remaining amount detection unit 14 detects the remaining amount of the battery 6. The remaining amount detection unit 14 transmits remaining amount information indicating the detected remaining amount to the ECU 13.

  FIG. 2 is a block diagram of the remaining amount detection unit 14. Of the elements shown in FIG. 2, the same elements as those shown in FIG. 1 are given the same reference numerals.

  The remaining amount detection unit 14 includes a voltage detection circuit 14a, a current detection circuit 14b, a central processing unit (CPU) 14c, a read-only memory (ROM) 14d, a random-access memory (RAM) 14e, and an interface unit (I / F). 14f and 14g are included. Of these elements, the CPU 14c, ROM 14d, RAM 14e, and interface units 14f and 14g are connected to a bus 14h, respectively.

  The voltage detection circuit 14a detects the voltage between the positive and negative electrodes of the battery 6, that is, the battery voltage. The voltage detection circuit 14a outputs voltage information representing the detected battery voltage.

  The current detection circuit 14b has a current sensor that measures a magnetic field change caused by a current change and converts it into a current value, and detects a battery current based on the current sensor. The current detection circuit 14b outputs current information representing the detected battery current.

  The CPU 14c performs information processing for controlling the operation of each element to be controlled by the ECU 13, based on the operating system and application programs stored in the ROM 14d and the RAM 14e. The CPU 14c functions as first and second determination means, charge mode determination means, and selection means by executing processing to be described later.

  The ROM 14d stores the above operating system. The ROM 14d may store the above application program. The ROM 14d stores data to be referred to when the CPU 14c performs various processes. Note that the RAM 14e may store all or part of data referred to when the CPU 14c performs various processes. Further, an EEPROM (electrically erasable programmable read-only memory) may be provided in the remaining amount detection unit 14, and this EEPROM may store all or a part of data referred to when the CPU 14c performs various processes.

  The RAM 14e is used as a so-called work area that stores data temporarily used when the CPU 14c performs various processes. The RAM 14e may store the above application program.

  The application program may be stored in the EEPROM.

  The application program stored in the ROM 14d, the RAM 14e, or the EEPROM includes a control program described regarding processing to be described later. When this control program is stored in the RAM 14e or the EEPROM, the ECU 13, the unit including the ECU 13, or the electric vehicle 100 is generally transferred in a state where the control program is stored in the RAM 14e or the EEPROM. However, the ECU 13, the unit including the ECU 13, or the electric vehicle 100 is transferred in a state where the control program is not stored in the RAM 14 e or the EEPROM, and is removable such as a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. The control program may be recorded on a recording medium or transferred via a network, and the control program may be written in the RAM 14e or the EEPROM.

  The interface unit 14f physically connects the voltage detection circuit 14a and the current detection circuit 14b. The interface unit 14f takes in the voltage information output from the voltage detection circuit 14a and the current information output from the current detection circuit 14b under an instruction from the CPU 14c and passes them to the CPU 14c.

  The interface unit 14g physically connects the ECU 13. The interface unit 14g transmits remaining amount information representing the remaining amount of the battery 6 to the ECU 13 under an instruction from the CPU 14c.

  Next, the operation of the electric vehicle 100 configured as described above will be described. The electric vehicle 100 has various functions similar to those provided in another existing electric vehicle. However, since the operations related to these functions are the same as those in another existing electric vehicle, detailed description thereof is omitted. . In the following, the operation of the remaining amount detection unit 14 will be described in detail.

  The CPU 14c executes the first and second determination processes in parallel. In the first determination process, the CPU 14c periodically acquires the voltage information output from the voltage detection circuit 14a via the interface unit 14f, and based on the battery voltage represented by the voltage information, the CPU 14c performs a known voltage method. Determine the remaining amount. In the second determination process, the CPU 14c periodically acquires current information output from the current detection circuit 14b via the interface unit 14f, and based on the battery current represented by the current information, the battery 14c performs a known current integration method. 6 is determined.

  The CPU 14c executes the process shown in FIG. 3 separately from the first and second determination processes. The CPU 14c repeatedly executes the processing shown in FIG. 3 at predetermined execution timings. The execution timing is, for example, a timing at regular time intervals.

  In step Sa1, the CPU 14c acquires voltage information output from the voltage detection circuit 14a and current information output from the current detection circuit 14b.

  In step Sa2, the CPU 14c determines whether or not the charging mode is the “rapid charging mode”. If the determination is YES (“rapid charging mode”), the CPU 14c proceeds to step Sa3.

  In step Sa3, the CPU 14c confirms whether or not the quick charging is finished. If YES is determined here, the CPU 14c proceeds to step Sa4.

  In step Sa4, the CPU 14c starts a timer. After this, the CPU 14c proceeds to step Sa5.

Meanwhile, CPU 14c proceeds to step Sa 7 when it is determined that the NO ( "rapid charge mode No") in step Sa2.

  On the other hand, if it is determined as NO (“continuation of quick charge”) in step Sa3, the CPU 14c proceeds to step Sa9.

  In step Sa5, the CPU 14c checks whether or not the timer has expired. If it is determined YES here that the time-up indicating the elapse of the predetermined time T has been performed, the CPU 14c proceeds to step Sa6.

  The predetermined time T can be arbitrarily set, but is desirably set as a standby time until the voltage is stabilized. Immediately after the “rapid charging mode” in which charging is performed with a large power capacity, the voltage becomes unstable, and even if the remaining amount determined by the so-called “voltage method” based on the voltage value is detected in that state, it can be detected accurately. This is because it becomes difficult.

  In step Sa6, the CPU 14c stops the timer.

  In step Sa7, the CPU 14c turns off the flag. After this, the CPU 14c proceeds to step Sa8.

  In step Sa8, the CPU 14c transmits the remaining amount determined by the first determination process, that is, the voltage method, to the ECU 13 as a detection value.

  On the other hand, when it is determined NO in step Sa5, the CPU 14c proceeds to step Sa9.

  In step Sa9, the CPU 14c turns on the flag. After this, the CPU 14c proceeds to step Sa10.

  In step Sa10, the CPU 14c transmits the remaining amount determined by the second determination process, that is, the current integration method, to the ECU 13 as a detection value.

  And CPU14c complete | finishes the process shown in FIG. 3 with transmission of residual amount detection value.

  FIG. 4 is a diagram illustrating an example of the relationship between the remaining amount detection method and the charging mode.

  The current integration method is performed during the quick charge mode, and the current integration method is continued immediately after the end of the quick charge.

  After the rapid charging is completed, the remaining amount detection method is switched from the current integration method to the voltage method after a predetermined time T (for example, a standby time for voltage stabilization) has elapsed.

  Thereafter, the remaining amount is detected by the voltage method while the vehicle is running or during normal charging, and when the quick charge is started next, the remaining amount detection method is switched from the voltage method to the current integration method.

  This embodiment can be variously modified as follows.

  The present invention can also be applied to other types of electric vehicles such as hybrid vehicles, electric motorcycles, and electric assist bicycles. In such an electric vehicle including the electric vehicle in the above-described embodiment, it is necessary to detect the remaining amount of the secondary battery for driving the vehicle more accurately in order to grasp the cruising range and the charging timing. Therefore, the present invention is preferable.

  The remaining amount detection unit 14 can be detached from the main body 1 and can be realized as a module independent of the electric vehicle. Such a remaining amount detection unit 14 can also be used in an electric device other than an electric vehicle. In this case, it can also be used to detect the remaining amount of the primary battery.

The present invention is not limited to the above-described embodiments as they are, and can be embodied by modifying the constituent elements without departing from the scope of the invention in the implementation stage. Various inventions can be formed by appropriately combining a plurality of constituent elements disclosed in the above-described embodiments. For example, you may delete some components from all the components shown by embodiment mentioned above. Furthermore, you may combine the component covering different embodiment suitably.
Hereinafter, the invention described in the scope of claims of the present application will be appended.
(1) Voltage detection means for detecting the voltage value of the battery, current detection means for detecting the current value of the battery, and first for determining the remaining amount of the battery based on the voltage value detected by the voltage detection means Determination means; second determination means for determining the remaining amount of the battery based on an integrated value of the current value detected by the current detection means; charge mode determination means for determining the charge mode of the battery; A remaining amount detection unit comprising: a selection unit that selects one of the first determination unit and the second determination unit based on a determination result of a charging mode determination unit.
(2) The charging mode has at least two types of charging modes with different supply power capacities, and the selection unit determines that the charging mode determination unit determines the end of the quick charge mode with a large supply power capacity. The remaining amount detection unit according to (1), wherein the first determination unit is selected after a predetermined time has elapsed.
(3) The remaining amount detection according to (2), wherein the selection unit selects the second determination unit when the charge mode determination unit determines the quick charge mode. unit.

  DESCRIPTION OF SYMBOLS 1 ... Main body, 2 ... Front wheel, 3 ... Rear wheel, 4 ... Motor, 5 ... Reduction gear, 6 ... Battery, 6a ... Battery cell, 7 ... Inverter, 8 ... Feed line, 9, 10 ... Contactor, 11 ... Fuse, DESCRIPTION OF SYMBOLS 12 ... Charge plug, 13 ... ECU, 14 ... Remaining amount detection unit, 14a ... Voltage detection circuit, 14b ... Current detection circuit, 14c ... CPU, 14d ... ROM, 14e ... RAM, 14f, 14g ... Interface unit, 14h ... Bus 100 ... Electric car.

Claims (1)

Voltage detection means for detecting the voltage value of the battery;
Current detection means for detecting the current value of the battery;
First determination means for determining the remaining amount of the battery based on the voltage value detected by the voltage detection means;
Second determination means for determining the remaining amount of the battery based on an integrated value of the current value detected by the current detection means;
Charging mode determining means for determining a charging mode of the battery;
A selection unit that selects one of the first determination unit and the second determination unit based on a determination result of the charge mode determination unit ;
The charging mode has at least two types of charging modes with different supply power capacities,
The selection unit selects the first determination unit after a lapse of a predetermined time after the charge mode determination unit determines the end of the quick charge mode with a large supply power capacity, and the charge mode determination unit The remaining amount detection unit , wherein the second determination unit is selected when the charging mode is determined .

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