JP2022169105A - electric vehicle - Google Patents

Abstract

To control input and output limit of a power storage device more properly.SOLUTION: An electric vehicle includes a power storage device having multiple battery cells, and a control device for controlling input and output limit of the power storage device. When vibration acting on the vehicle is equal to or larger than a threshold, the control device integrates index values corresponding to the vibration to calculate an integrated vibration value, and controls the input and output limit of the power storage device so that the larger the integrated vibration value, the higher the limit is imposed. Thus, the input and output limit of the power storage device can be controlled more properly.SELECTED DRAWING: Figure 2

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle, and more particularly to an electric vehicle including a control device that controls input/output restriction of a power storage device.

Conventionally, for this type of electric vehicle, the vibration intensity of the assembled battery determined for each point on the planned travel route of the vehicle is acquired, and the acquired vibration intensity and deterioration index value are used to determine the difficulty of progressing high-rate deterioration. There has been proposed a method for calculating a resistance value indicating the (see, for example, Patent Document 1). In this electric vehicle, high-rate deterioration suppression control is executed before the vehicle reaches a point where the calculated resistance value is less than the reference value, thereby making the timing of suppressing high-rate deterioration appropriate.

JP 2019-016521 A

When a power storage device with multiple battery cells is subjected to large vibrations while the vehicle is running, the performance of the power storage device deteriorates due to the displacement of the facing positions of the electrodes and the rubbing of the separator. There is a discrepancy between the state and In this case, it may not be possible to control the input/output restriction of the power storage device that is suitable for the actual state of the power storage device.

A main object of the electric vehicle of the present invention is to more appropriately control the input/output limitation of the power storage device.

The electric vehicle of the present invention employs the following means in order to achieve the above main object.

The electric vehicle of the present invention is
An electric vehicle comprising: a power storage device having a plurality of battery cells; and a control device that controls input/output limitations of the power storage device,
The control device calculates an integrated vibration value by accumulating an index value when vibration acting on the power storage device is equal to or greater than a threshold value, and the input/output restriction is performed such that the larger the integrated vibration value, the more the restriction is imposed. to control the
It is characterized by

In the electric vehicle of the present invention, the integrated vibration value is calculated by integrating the index values when the vibration acting on the power storage device is equal to or greater than the threshold value. Then, the input/output restriction of the power storage device is controlled such that the greater the integrated vibration value, the more restriction is imposed. Thereby, the input/output limitation of the power storage device can be controlled more appropriately. Here, as the threshold, it is possible to use the lower limit of vibration that is highly likely to degrade the performance of the power storage device or the lower limit of vibration that is highly likely to degrade the stability of the power storage device. As the index value, the vibration intensity may be used, or a counter that is incremented by 1 or by a value corresponding to the vibration intensity may be used. As the control of the input/output limit of the power storage device, for example, a plurality of maps are prepared that define the input/output limit of the power storage device that imposes limits based on the power storage rate and temperature of the power storage device, and the vibration integrated value is large. The input/output limit of the power storage device is set using a map that imposes a limit of approx. Then, the input/output limit of the power storage device can be set by multiplying the map by a coefficient that decreases as the integrated vibration value increases.

1 is a configuration diagram showing a schematic configuration of an electric vehicle 20 as an embodiment of the present invention; FIG. 5 is a flowchart showing an example of an input/output limit setting process executed by an electronic control unit 50; FIG. 4 is an explanatory diagram showing the relationship between an integrated vibration value ΣG and an input/output limit setting map MAP; FIG. 4 is an explanatory diagram showing an example of input/output restriction setting maps MAP(1) to MAP(n); FIG. 5 is an explanatory diagram showing an example of the relationship between the integrated vibration value ΣG and the coefficient k; FIG. 11 is a flow chart showing an example of input/output restriction setting processing according to a modification; FIG.

Next, a mode for carrying out the present invention will be described using examples.

FIG. 1 is a configuration diagram showing the outline of the configuration of an electric vehicle 20 as one embodiment of the present invention. The electric vehicle 20 of the embodiment includes a motor 32 for running, an inverter 34, a battery 36 as a power storage device, and an electronic control unit 50, as shown.

The motor 32 is configured as a synchronous generator-motor, and includes a rotor in which permanent magnets are embedded in a rotor core, and a stator in which a three-phase coil is wound around the stator core. The rotor of the motor 32 is connected to a drive shaft 26 which is connected to drive wheels 22a and 22b through a differential gear 24. As shown in FIG.

The inverter 34 is used to drive the motor 32 and is connected to the battery 36 via the power line 38. The inverter 34 is connected in parallel to the six transistors T11 to T16 as switching elements and the six transistors T11 to T16. and six diodes D11-D16. The transistors T11 to T16 are arranged in pairs so as to be on the source side and the sink side with respect to the positive line and the negative line of the power line 38, respectively. Each of the three-phase coils (U-phase, V-phase, and W-phase coils) of the motor 32 is connected to each of the connection points between the transistors T11 to T16 that form a pair. Therefore, when a voltage is applied to the inverter 34, the electronic control unit 50 adjusts the ratio of the ON time of the paired transistors T11 to T16, thereby forming a rotating magnetic field in the three-phase coil, and 32 is rotationally driven.

The battery 36 is configured as an assembled battery in which a plurality of lithium-ion secondary battery cells or nickel-hydrogen secondary battery cells are connected in series or in parallel, for example, and is connected to the inverter 34 via the power line 38 as described above. It is A capacitor 39 is attached to the positive line and the negative line of the power line 38 .

The electronic control unit 50 is configured as a microprocessor centered on a CPU 52. In addition to the CPU 52, it also includes a ROM 54 for storing processing programs, a RAM for temporarily storing data, an input/output port, and a communication port. Signals from various sensors are input to the electronic control unit 50 through input ports. Signals input to the electronic control unit 50 include, for example, the rotational position θm from a rotational position sensor (for example, a resolver) 32a that detects the rotational position of the rotor of the motor 32, and the U-phase and V-phase phases of the motor 32. Phase currents Iu and Iv from current sensors 32u and 32v that detect currents 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, the temperature attached to the battery 36 Temperature Tb of battery 36 from sensor 36c and voltage VH of capacitor 39 (power line 38) from a voltage sensor (not shown) attached between terminals of capacitor 39 can also be mentioned. The ignition signal from the start switch 60 and the shift position SP from the shift position sensor 62 that detects the operating position of the shift lever 61 can also be mentioned. Accelerator opening Acc from accelerator pedal position sensor 64 that detects the amount of depression of accelerator pedal 63, brake pedal position BP from brake pedal position sensor 66 that detects the amount of depression of brake pedal 65, vehicle speed V from vehicle speed sensor 68, Vibrations G from the vibration sensor 69 can also be mentioned. An acceleration sensor or the like can also be used as the vibration sensor 69 . Various control signals are output from the electronic control unit 50 through an output port. Signals output from the electronic control unit 50 include switching control signals for the transistors T11 to T16 of the inverter 34, for example.

The electronic control unit 50 calculates the electrical angle θe and the rotation speed Nm of the motor 32 based on the rotational position θm of the rotor of the motor 32 from the rotational position sensor 32a. The electronic control unit 50 estimates the torque Tm of the motor 32 based on the U-phase and V-phase currents Iu and Iv of the motor 32 from the current sensors 32u and 32v. The electronic control unit 50 estimates the power consumption Pm of the motor 32 as the product of the rotational speed Nm of the motor 32 and the torque Tm. The electronic control unit 50 calculates the charging ratio SOC based on the integrated value of the current Ib of the battery 36 from the current sensor 36b. The power storage ratio SOC is the ratio of the capacity of electric power that can be discharged from the battery 36 to the total capacity of the battery 36 . The battery ECU 52 also calculates an output limit Wout and an input limit Win of the battery 50 based on the temperature Tb of the battery 50 and the power storage ratio SOC from the temperature sensor 36c.

In the electric vehicle 20 of the embodiment thus configured, the electronic control unit 50 sets the required torque Td* required of the drive shaft 26 based on the accelerator opening Acc and the vehicle speed V, and the output limit Wout of the battery 36 and A torque command Tm* for the motor 32 is set so that the required torque Td* is output to the drive shaft 26 within the range of the input limit Win. Then, switching control of the transistors T11 to T16 of the inverter 34 is performed so that the motor 32 is driven by the torque command Tm*.

Next, the operation of the electric vehicle 20 of the embodiment configured as described above, in particular, the operation when limiting the output limit Wout and the input limit Win of the battery 36 will be described. FIG. 2 is a flow chart showing an example of the input/output limit setting process executed by the electronic control unit 50. As shown in FIG.

When the input/output limit setting process is executed, first, the vibration G is input from the vibration sensor 69 (step S100), and it is determined whether or not the vibration G is equal to or greater than the threshold value Gref1 (step S110). The threshold value Gref1 is, for example, a lower limit value of vibration that is highly likely to degrade the performance of the battery 36, and can be determined in advance by experiments or the like in consideration of the type and structure of the battery 36. When it is determined that the vibration G is less than the threshold Gref1, this process is terminated. In this case, the previously set input/output restriction setting map is used. The input/output setting map will be described later.

When it is determined in step S110 that the vibration G is greater than or equal to the threshold value Gref1, a vibration integrated value ΣG is calculated as an integrated value of the vibration G (step S120). Then, an input/output limit setting map MAP for setting the output limit Wout and the input limit Win of the battery 36 is set so that the limit increases as the integrated vibration integrated value ΣG increases (step S130), and the process ends. . FIG. 3 is an explanatory diagram showing the relationship between the vibration integrated value ΣG and the input/output limit setting map MAP, and FIG. 4 is an explanatory diagram showing an example of the input/output limit setting maps MAP(1) to (n). . In the example of FIG. 3, MAP(1), MAP(2), . . . MAP( n) are assigned. Each of the input/output limit setting maps MAP(1)-(n) is set with respect to the temperature Tb of the battery 36 and the charge rate SOC. The input/output limit setting map MAP(1) is a map indicating the output limit Wout and the input limit Win as rated values of the battery 36 at which performance degradation is not recognized. FIG. 10 is a map showing an output limit Wout and an input limit Win with large limits imposed on MAP(1); FIG. Therefore, in the input/output limit setting process of the embodiment, the output limit Wout and the input limit Win are set according to a map showing the output limit Wout and the input limit Win that are imposed with greater limits as the vibration integrated value ΣG increases. . In the input/output limit setting map MAP, when the temperature Tb of the battery 36 is extremely low or extremely high, the output limit Wout is smaller than that at the standard temperature, and the power storage rate SOC is within a certain value or less range. becomes smaller as the charge ratio SOC becomes smaller. Also, the input limit Win has a smaller absolute value when the temperature Tb of the battery 36 is extremely low or extremely high than when it is at the standard temperature, and the power storage ratio SOC is large in a range of a certain value or higher. As a result, the absolute value becomes smaller.

In the electric vehicle 20 of the embodiment described above, the vibration integrated value ΣG is calculated when the vibration G is equal to or greater than the threshold value Gref1, and the input/output restriction setting map MAP is set such that the greater the vibration integrated value ΣG, the greater the restriction. to set the output limit Wout and the input limit Win of the battery 36 . As a result, the output limit Wout and the input limit Win of the battery 36 can be set more appropriately.

In the electric vehicle 20 of the embodiment, the vibration integrated value ΣG is calculated when the vibration G is equal to or greater than the threshold value Gref1, and the input/output restriction setting map MAP is set such that the greater the vibration integrated value ΣG, the greater the restriction. However, when the vibration G is equal to or greater than the threshold value Gref1, an index value corresponding to the vibration G is integrated, and an input/output limit setting map MAP is set such that the larger the integrated value of the index value, the larger the limit. A counter C may be counted up when G is equal to or greater than the threshold value Gref1, and an input/output restriction setting map MAP may be set such that the greater the counter C, the greater the restriction.

In the electric vehicle 20 of the embodiment, the vibration integrated value ΣG is calculated when the vibration G is equal to or greater than the threshold value Gref1, and the input/output restriction setting map MAP is set such that the greater the vibration integrated value ΣG, the greater the restriction. However, when the vibration G is equal to or greater than the threshold value Gref1, the integrated vibration value ΣG is calculated, and the coefficient k that decreases as the integrated vibration value ΣG increases is set. Alternatively, the output limit Wout and the input limit Win may be set by multiplying the output limit Wout and the input limit Win (map indicating the output limit Wout and the input limit Win) by a coefficient k. FIG. 5 is an explanatory diagram showing an example of the relationship between the integrated vibration value ΣG and the coefficient k. In the example of FIG. 5, the vibration integrated value ΣG is k(1), k(2), . is assigned.

In the electric vehicle 20 of the embodiment, the lower limit value of vibration that is highly likely to degrade the performance of the battery 36 is used as the threshold Gref1. A lower limit value may also be used. Since the lower limit of vibration that is likely to degrade the stability of the battery 36 is greater than the lower limit of vibration that is likely to degrade the performance of the battery 36, the threshold Gref1 is a larger value. When simultaneously considering deterioration in performance and deterioration in stability of the battery 36, for example, the input/output limit setting process illustrated in FIG. 6 may be executed. In the input/output limit setting process of FIG. 6, the vibration G is input (step S200), and whether or not the vibration G is equal to or greater than the threshold Gref1 set as the lower limit of the vibration that is highly likely to degrade the performance of the battery 36. is determined (step S210). When it is determined that the vibration G is less than the threshold Gref1, this process is terminated. On the other hand, when it is determined that the vibration G is equal to or greater than the threshold value Gref1, the counter C is incremented by 1 (step S220), and the vibration G is set as the lower limit of vibration that is highly likely to lower the stability of the battery 36. It is determined whether or not it is equal to or greater than a threshold Gref2 (Gref2>Gref1) (step S230). When it is determined that the vibration G is less than the threshold value Gref2, an input/output restriction setting map MAP is set so that the restriction increases as the counter C increases (step S250), and this process ends. On the other hand, when it is determined that the vibration G is equal to or greater than the threshold value Gref2, the counter C is incremented by the value Cset (step S240), and an input/output restriction setting map MAP is set such that the greater the counter C, the greater the restriction (step S250). , the process ends. Here, the value Cset can be a value that imposes two, three, or several stages of restrictions on the output limit Wout and the input limit Win of the battery 36 . The output limit Wout and the input limit Win of the battery 36 can be set more appropriately in the input/output limit setting process of FIG. 6 as well.

In the embodiment, the configuration of the electric vehicle 20 including the motor 32 for running, the inverter 34 and the battery 36 is adopted. However, a configuration of a parallel type or series type hybrid vehicle having an engine in addition to a driving motor, an inverter, and a battery may also be used. Further, a configuration of a fuel cell vehicle including a fuel cell in addition to a motor for running, an inverter, and a battery may be employed.

The correspondence relationship between the main elements of the embodiments and the main elements of the invention described in the column of Means for Solving the Problems will be described. In the embodiment, the battery 36 corresponds to the "storage device" and the electronic control unit 50 corresponds to the "control device".

Note that the correspondence relationship between the main elements of the examples and the main elements of the invention described in the column of Means for Solving the Problems is the Since it is an example for specifically explaining the mode for solving the problem, it does not limit the elements of the invention described in the column of the means for solving the problem. That is, the interpretation of the invention described in the column of Means to Solve the Problem should be made based on the description in that column, and the Examples are based on the description of the invention described in the column of Means to Solve the Problem. This is only a specific example.

Although the embodiments for carrying out the present invention have been described above, the present invention is not limited to such embodiments at all, and can be modified in various forms without departing from the scope of the present invention. Of course, it can be implemented.

INDUSTRIAL APPLICABILITY The present invention is applicable to the electric vehicle manufacturing industry and the like.

20 electric vehicle, 22a, 22b drive wheels, 24 differential gear, 26 drive shaft, 32 motor, 32a rotational position sensor, 32u, 32v current sensor, 34 inverter, 36 battery, 36a voltage sensor, 36b current sensor, 36c temperature sensor, 38 power line, 39 capacitor, 50 electronic control unit, 52 CPU, 54 ROM, 60 start switch, 61 shift lever, 62 shift position sensor, 63 accelerator pedal, 64 accelerator pedal position sensor, 65 brake pedal, 66 brake pedal position sensor , 68 vehicle speed sensor, 69 vibration sensor.

Claims (1)

An electric vehicle comprising: a power storage device having a plurality of battery cells; and a control device that controls input/output limitations of the power storage device,
The control device calculates an integrated vibration value by accumulating an index value corresponding to the vibration when the vibration acting on the vehicle is equal to or greater than a threshold value, and the input is restricted so that the larger the integrated vibration value is, the more the restriction is imposed. to control output limits,
An electric vehicle characterized by:

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