JP7087936B2 - Full charge capacity estimation device - Google Patents

Description

The present invention relates to a full charge capacity estimation device, and more particularly to a full charge capacity estimation device that estimates an estimated full charge capacity as an estimated value of the full charge capacity of the power storage device.

Conventionally, as this type of full charge capacity estimation device, a device that estimates the full charge capacity of the power storage device based on the difference in the storage ratio of the power storage device before and after charging and the integrated charge current value has been proposed (for example,). See Patent Document 1). Here, the storage ratio is the ratio of the stored capacity to the total capacity of the power storage device, and is shown by, for example, a percentage display with respect to the total capacity. The fully charged capacity is a percentage or a unit of [Ah], [Wh. ] Is displayed in units such as. Further, the full charge capacity may be displayed by the distance that can be electrically traveled or a percentage thereof using the user's electricity cost. The display means may be a meter or a dealer's display device.

Japanese Unexamined Patent Publication No. 2013-101072

Generally, the full charge capacity of the power storage device decreases due to aged deterioration of the power storage device, but since the degree of deterioration varies depending on the usage state, it is not possible to estimate the full charge capacity of the power storage device only by the number of years of use. When estimating the full charge capacity of the power storage device based on the difference in the storage ratio of the power storage device before and after charging and the integrated charging current value as in the above device, the full charge capacity is not eliminated when the polarization of the power storage device is not eliminated. If this is estimated, the estimation accuracy will be low, and it will not be possible to estimate an appropriate full charge capacity. Polarization can be resolved by leaving it to some extent, but the user cannot determine how long it should be left, and if it is not left for a sufficient amount of time, the accuracy will be high. If a bad estimation is made and the product is left for an excessive amount of time, the product is left for a long time, which gives the user a sense of discomfort.

The main purpose of the full charge capacity estimation device of the present invention is to more accurately estimate the full charge capacity of the power storage device.

The full charge capacity estimation device of the present invention has adopted the following means in order to achieve the above-mentioned main object.

The full charge capacity estimation device of the present invention is
It is a full charge capacity estimation device that estimates the estimated full charge capacity as an estimated value of the full charge capacity of the power storage device.
When the difference between the estimated full charge capacity and the full charge capacity due to the number of years of use based on the number of years of use of the power storage device is equal to or greater than a predetermined value, the waiting time is set based on the difference and the power storage device is charged to full charge. When performing the above, charging is started after the waiting time has elapsed, and the estimated full charge capacity is estimated based on the difference in the storage ratio before and after charging and the integrated value of the charging current until full charging.
It is characterized by that.

In the full charge capacity estimation device of the present invention, when the difference between the estimated full charge capacity up to that point and the full charge capacity due to the number of years of use based on the number of years of use of the power storage device is equal to or greater than a predetermined value, first, the waiting period is based on the difference. Set the time. Then, when charging the power storage device until it is fully charged, charging is started after the waiting period has elapsed, and it is estimated based on the difference in the storage ratio before and after charging and the integrated value of the charging current until full charge. Estimate the full charge capacity. Charging is started after waiting for a waiting time based on the difference between the estimated full charge capacity and the full charge capacity due to the number of years of use. As a result, a more appropriate waiting period can be set, and the estimated full charge capacity can be estimated more appropriately.

Here, it is preferable to set the waiting period so that the larger the difference between the estimated full charge capacity and the full charge capacity due to the number of years of use, the larger the waiting time. This is because it is considered that the larger the difference, the greater the influence of polarization. The full charge capacity can be calculated by dividing the integrated value of the charging current by the difference in the storage ratio before and after charging.

It is a block diagram which shows the outline of the structure of the electric vehicle 20 equipped with the full charge capacity estimation device as one Embodiment of this invention. It is a flowchart which shows an example of the full charge capacity estimation process executed by an electronic control unit 70. It is explanatory drawing which shows an example of the map for setting the full charge capacity due to the years of use. It is explanatory drawing which shows an example of the map for setting the waiting period time before charging.

Next, an embodiment for carrying out the present invention will be described with reference to examples.

FIG. 1 is a configuration diagram showing an outline of the configuration of an electric vehicle 20 equipped with a full charge capacity estimation device as an embodiment of the present invention. As shown in the figure, the electric vehicle 20 of the embodiment includes a motor 32, an inverter 34, a battery 36 as a DC power source, a charging relay 50, and an electronic control unit 70.

The motor 32 is configured as, for example, a synchronous generator motor, and the rotor is connected to a drive shaft 26 connected to the drive wheels 22a and 22b via a differential gear 24. The inverter 34 is used to drive the motor 32 and is connected to the battery 36 via the power line 38 and the system main relay 35. The motor 32 is rotationally driven by switching control of a plurality of switching elements (not shown) of the inverter 34 by the electronic control unit 70.

The battery 36 is configured as, for example, a lithium ion secondary battery or a nickel hydrogen secondary battery, and exchanges electric power with the motor 32 via the system main relay 35 and the inverter 34. That is, by controlling the power running of the motor 32, the power for driving is output from the motor 32 by using the electric power from the battery 36, and by regeneratively controlling the motor 32, the battery 36 is charged by the regenerative electric power from the motor 32.

The charging relay 50 is provided in the power line 52 connecting the vehicle side connector 51 connected to the stand side connector 91 of the charging stand 90 outside the vehicle and the power line 38. Although not shown, the charging relay 50 includes a positive electrode relay and a negative electrode relay.

Although not shown, the electronic control unit 70 is configured as a microprocessor centered on a CPU, and in addition to the CPU, a ROM for storing a processing program, a RAM for temporarily storing data, a flash memory, and input / output. Equipped with ports, communication ports, etc.

Signals from various sensors are input to the electronic control unit 70 via the input port. The signals input to the electronic control unit 70 include, for example, the rotation position θm of the rotor of the motor 32 from a rotation position sensor (not shown) that detects the rotation position of the rotor of the motor 32, and the phase of each phase of the motor 32. Phase currents Iu, Iv, Iw of each phase of the motor 32 from a current sensor (not shown) that detects the current can be mentioned. Further, the voltage Vb of the battery 36 from the voltage sensor 36a attached between the terminals of the battery 36, the current Ib of the battery 36 from the current sensor 36b attached to the output terminal of the battery 36, and the temperature attached to the battery 36. The temperature Tb of the battery 36 from the sensor 36c can also be mentioned. A connection detection signal from the connection detection sensor 53 that detects whether or not the vehicle-side connector 51 is connected to the stand-side connector 91, and a voltage attached to the power line 52 between the vehicle-side connector 51 and the charging relay 50. The charging voltage Vchg from the sensor 52a can also be mentioned. Although not shown, the ignition signal from the ignition switch, the shift position SP from the shift position sensor that detects the operation position of the shift lever, and the accelerator opening Acc from the accelerator pedal position sensor that detects the amount of depression of the accelerator pedal, Brake pedal position BP from the brake pedal position sensor that detects the amount of depression of the brake pedal, vehicle speed V from the vehicle speed sensor, and the like can also be mentioned.

Various control signals are output from the electronic control unit 70 via the output port. Examples of the signal output from the electronic control unit 70 include a control signal to the inverter 34, a control signal to the system main relay 35, and a control signal to the charging relay 50. Further, when the vehicle-side connector 51 is connected to the stand-side connector 91, information necessary for charging the charging stand 90 via the communication lines of the vehicle-side connector 51 and the stand-side connector 91 can also be mentioned. The electronic control unit 70 calculates the storage amount Sb and the storage ratio SOC of the battery 36 based on the integrated value of the input / output current Ib of the battery 36 from the current sensor 36b. Here, the storage amount Cb is the amount of electric power that can be discharged from the battery 36, and the storage ratio SOC is the ratio of the storage amount Cb to the total capacity Cap of the battery 36.

In the electric vehicle 20 of the embodiment configured in this way, the electronic control unit 70 that executes the process of estimating the estimated full charge capacity of the battery 50 corresponds to the full charge capacity estimation device. FIG. 2 is a flowchart showing an example of a full charge capacity estimation process executed by the electronic control unit 70.

When the full charge capacity estimation process is executed, the electronic control unit 70 first executes a process of acquiring the estimated full charge capacity Mest and the number of years of use Nen (step S100). The estimated full charge capacity Mest is the one finally calculated in this process, and the number of years of use Nen is the number of years since the start of use of the battery 50. These are acquired by inputting what is stored in a flash memory or the like (not shown) of the electronic control unit 70.

Subsequently, the acquired years of use Nen is applied to the map for setting the full charge capacity due to the years of use to derive the full charge capacity Menne due to the years of use (step S110). FIG. 3 shows an example of a map for setting a full charge capacity due to years of use. This map can be determined experimentally or the like for the battery 50. As shown in the figure, the larger the number of years of use Nen, the smaller the full charge capacity Mnen due to the number of years of use.

Next, it is determined whether or not the difference between the estimated full charge capacity Mest and the full charge capacity Menne due to years of use is equal to or greater than the threshold value Mref (step S120). As the threshold value Mref, a maximum value that can be tolerated as a difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to years of use, or a value slightly larger than this can be used. When it is determined that the difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to the number of years of use is less than the threshold value Mref, it is determined that the estimated full charge capacity Mest is properly estimated, and this process is terminated.

When it is determined in step S120 that the difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to the number of years of use is equal to or greater than the threshold value Mref, it is determined that the estimated full charge capacity Mest is inappropriate, and this difference is used as the waiting time before charging. The waiting time before charging Wait is set by applying it to the setting map (step S130). FIG. 4 shows an example of a map for setting the waiting period before charging. As shown in the figure, the waiting period before charging Twait is set so that the difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to the number of years of use becomes larger. This is based on the fact that the larger the difference, the greater the effect of polarization.

Subsequently, it is confirmed that the stand-side connector 91 of the charging stand 90 is connected to the vehicle-side connector 51 (step S140), and the waiting period Twait for charging has elapsed (step S150), and the voltage sensor is used. The voltage Vb from 36a is acquired as the charging start voltage Vstart (step S160). Then, charging of the battery 50 with electric power from the charging stand 90 is started (step S170), and integration of the current Ib from the current sensor 36b is started (step S180).

Next, after waiting for the charging of the battery 50 by the electric power from the charging stand 90 to be properly completed (step S190), the voltage Vb from the voltage sensor 36a is acquired as the voltage Vb at the end of charging (step S200), and is acquired. The estimated full charge capacity Mest is calculated based on the charged start voltage Vstart, the charge end voltage Vend, and the integrated charge current integrated value Ih (step S210), and the present process is terminated. In the calculation of the estimated full charge capacity Mest, the storage ratio Start at the start of charging and the storage ratio Send at the end of charging are obtained based on the voltage V Start at the start of charging and the voltage Vend at the end of charging, and the integrated charging current value Ih is charged. It can be calculated by dividing by the difference (Send-Start) of the front and rear storage ratios. The charging start voltage Vstart can be regarded as the open circuit voltage OCV of the battery 50 because the polarization of the battery 50 is eliminated by the lapse of the waiting time Twait before charging. Therefore, the storage ratio Sstart at the start of charging can be more appropriately obtained based on the voltage Vstart at the start of charging. As a result, the estimated full charge capacity Mest can be estimated more appropriately.

In the full charge capacity estimation device mounted on the electric vehicle 20 of the above-described embodiment, the waiting period before charging Wait is set based on the difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to the number of years of use, and before charging. After the waiting time Twait has elapsed, the charging start voltage Vstart is acquired, the charging of the battery 50 by the electric power from the charging stand 90 is started, and the integration of the charging current Ib is started. Then, when charging is completed, the charge end voltage Vend is acquired, and the estimated full charge capacity Mest is calculated based on the charge start voltage Vstart, the charge end voltage Vend, and the charge current integrated value Ih. Since the polarization of the battery 50 is eliminated by the lapse of the waiting period Twait before charging, the voltage Vstart at the start of charging can be regarded as the open circuit voltage OCV of the battery 50. Therefore, charging starts based on the voltage Vstart at the start of charging. It is possible to more appropriately obtain the electricity storage ratio Start at the time. As a result, the estimated full charge capacity Mest can be estimated more appropriately. Further, since the wait period before charging is set based on the difference between the estimated full charge capacity Mest and the full charge capacity Mnen due to the number of years of use, it is possible to suppress an inaccurate estimation due to a sufficient waiting period. This makes it possible to avoid inconveniences such as giving a sense of discomfort to the user due to an excessive waiting period.

In the embodiment, the full charge capacity estimation device is mounted on the electric vehicle 20, but it may be mounted on the hybrid vehicle or the fuel cell vehicle. Further, the full charge capacity estimation device may be mounted on a moving body other than the automobile, or may be incorporated in equipment other than the moving body.

Although the embodiments for carrying out the present invention have been described above with reference to the embodiments, the present invention is not limited to these embodiments and may be in various embodiments within the scope of the gist of the present invention. Of course it can be done.

The present invention can be used in the manufacturing industry of a full charge capacity estimation device and the like.

20 electric vehicle, 22a, 22b drive wheel, 24 differential gear, 26 drive shaft, 32 motor, 34 inverter, 35 system main relay, 36 battery, 36a voltage sensor, 36b current sensor, 36c temperature sensor, 38 power line, 50 charging Relay, 51 vehicle side connector, 52 power line, 52a voltage sensor, 53 connection detection sensor, 70 electronic control unit, 90 charging stand, 91 stand side connector.

Claims (1)

It is a full charge capacity estimation device that estimates the estimated full charge capacity as an estimated value of the full charge capacity of the power storage device.
The estimated full charge capacity estimated at that time and the full charge capacity due to the number of years of use obtained based on the map for setting the full charge capacity, which is set so that the full charge capacity becomes smaller as the years of use of the power storage device become longer. When the difference is greater than or equal to a predetermined value, the standby time is set based on the standby time setting map defined so that the larger the difference is, the longer the standby time is set, and when the power storage device is charged to full charge. , Charging is started after the standby time has elapsed, and a new estimated full charge capacity is estimated by dividing the integrated value of the charge current until full charge by the difference in the storage ratio before and after charging.
A full charge capacity estimation device characterized by this.

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