Electric Vehicles

Abstract

An electric vehicle is provided, comprising: an electric motor connected to a wheel and configured to perform regenerative braking on the wheel; a storage battery configured to store regenerative power output by the electric motor through the regenerative braking; and a control device configured to control the regenerative braking in such a manner that the braking torque applied to the wheel is less than a maximum braking torque and the regenerative power output by the electric motor is less than the maximum regenerative power. The control device is configured to be able to change the maximum regenerative power, and when the maximum regenerative power is changed, the maximum braking torque is also changed.

Description

Technical Field

[0001] The technology disclosed in this specification relates to an electric vehicle. Background Art

[0002] Japanese Patent Application Laid-Open No. 2017-184459 discloses an electric vehicle comprising: an electric motor connected to wheels for regenerative braking of the wheels; a battery for storing regenerative power output by the electric motor through regenerative braking; and a control device for controlling the regenerative braking of the electric motor. Summary of the invention

[0003] Usually, in regenerative braking using an electric motor, in order to prevent the braking torque applied to the wheels from becoming too large, a limit value (hereinafter referred to as the maximum braking torque) is set for the braking torque. In addition, in order to prevent the regenerative power supplied to the battery from becoming too large, a limit value (hereinafter referred to as the maximum regenerative power) is also set for the regenerative power. In this case, when the speed of the electric vehicle is in the medium-high speed range, before the braking torque reaches the maximum braking torque, the regenerative braking using the electric motor is limited by making the regenerative power reach the maximum regenerative power. On the other hand, when the speed of the electric vehicle drops to the low speed range, before the regenerative power reaches the maximum regenerative power, the regenerative braking using the electric motor is limited by making the braking torque reach the maximum braking torque. As a result, there may be a difference in the braking torque actually generated between the medium-high speed range and the low speed range, but the difference is relatively small.

[0004] However, regarding the maximum regenerative power, its set value is sometimes changed according to, for example, the charge rate and temperature of the battery. For example, when the charge rate of the battery is high, the regenerative power supplied to the battery can be limited by reducing the maximum regenerative power compared to normal times. On the other hand, when the maximum regenerative power is reduced, regenerative braking is further limited in the medium and high speed range, and the actual braking torque generated is also further reduced. As a result, there are large changes in the actual braking torque generated between the medium and high speed range and the low speed range. The behavior of the electric vehicle that is different from the normal time may cause discomfort to the user riding the electric vehicle.

[0005] This specification provides a technology capable of appropriately limiting regenerative braking of an electric vehicle while suppressing the discomfort given to a user.

[0006] The technology disclosed in this specification is embodied as an electric vehicle. The electric vehicle comprises: an electric motor connected to a wheel and configured to perform regenerative braking on the wheel; a battery configured to store regenerative power output by the electric motor through regenerative braking; and a control device configured to control regenerative braking in such a manner that the braking torque applied to the wheel is less than the maximum braking torque and the regenerative power output by the electric motor is less than the maximum regenerative power. The control device is capable of changing the maximum regenerative power, and when the maximum regenerative power is changed, the maximum braking torque is also changed.

[0007] In the above-mentioned electric vehicle, in order to prevent the braking torque applied to the wheel from becoming too large, a maximum braking torque as a limiting value is set for the braking torque generated by regenerative braking. In addition, in order to prevent the regenerative power supplied to the battery from becoming too large, a maximum regenerative power as a limiting value is set for the regenerative power generated by regenerative braking. In addition, the control device can also be configured so that the maximum regenerative power can be changed according to, for example, the charging rate and temperature of the battery, and when the maximum regenerative power is changed, the maximum braking torque is also changed. Thus, when the maximum regenerative power is changed, the braking torque actually generated in the low-speed range can be changed in accordance with the change in the braking torque actually generated in the medium-high speed range. The change in the braking torque actually generated from the medium-high speed range to the low-speed range can be made consistent or similar before and after the maximum regenerative power is changed, which can suppress the discomfort caused to the user and appropriately limit the regenerative braking of the electric vehicle.

[0008] In the above aspect, the control device may be configured to determine a change width when changing the maximum braking torque, based on the change width when changing the maximum regenerative electric power.

[0009] In the above-mentioned embodiment, the control device may determine the variation range of the stimulus value accepted by the user before and after the change when changing the maximum regenerative power, and determine the variation range when changing the maximum braking torque based on the determined variation range of the stimulus value.

[0010] In the above aspect, the range of change of the stimulus value accepted by the user according to the range of change of the maximum regenerative electric power may be equal to the range of change of the stimulus value accepted by the user according to the range of change of the maximum braking torque.

[0011] In the above aspect, the control device may be capable of changing the maximum braking torque regardless of whether the maximum regenerative electric power is changed or not.

[0012] In the above-mentioned embodiment, the control device may determine the variation range of the stimulus value accepted by the user before and after the change when changing the maximum braking torque, and set limits on the braking torque in each vehicle speed range according to the determined variation range of the stimulus value.

[0013] In the above aspect, the control device may change the maximum braking torque according to the properties of a road surface on which the electric vehicle is traveling. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Features, advantages, and technical and industrial significance of exemplary embodiments of the present invention will be described below with reference to the accompanying drawings, in which like reference numerals represent like elements, and in which:

[0015] Figure 1 An electric vehicle according to an embodiment is schematically shown.

[0016] Figure 2 It is a block diagram showing the electrical structure of the electric vehicle according to the embodiment.

[0017] Figure 3 The relationship between the speed and the braking torque of the electric vehicle during normal regenerative braking is shown.

[0018] Figure 4 The relationship between the speed and the braking torque of the electric vehicle during regenerative braking at the time of limitation is shown.

[0019] Figure 5 This is a map showing the stimulus value received by the user in response to the combination of the speed and acceleration of the electric vehicle.

[0020] Figure 6 This is a flowchart showing an example of a control method executed by the electronic control unit.

[0021] Figure 7 This is a flowchart showing an example of another control method executed by the electronic control unit. DETAILED DESCRIPTION

[0022] In one embodiment of the present technology, the control device may also change the maximum regenerative power according to the charge rate or temperature of the battery. In this case, there is no particular limitation, but the control device may also reduce the maximum regenerative power when the charge rate of the battery is higher or the temperature of the battery is higher. According to such a structure, the load on the battery can be reduced and the degradation of the battery can be suppressed.

[0023] In one embodiment of the present technology, the control device may also determine the change range when changing the maximum braking torque according to the change range when the maximum regenerative power is changed. According to such a structure, when the maximum regenerative power is changed, the discomfort caused to the user can be effectively suppressed. However, the control device only needs to be able to change the maximum regenerative power in at least two stages (for example, normal and limited), and accordingly, it only needs to be able to change the maximum braking torque in at least two stages (similarly, normal and limited).

[0024] In the above-mentioned embodiment, the control device may also be such that, when the maximum regenerative power is changed, the range of change of the stimulus value accepted by the user before and after the change is determined, and the range of change when changing the maximum braking torque is determined based on the range of change of the determined stimulus value. The stimulus value accepted by the user for the acceleration and deceleration of the vehicle varies according to the combination of the speed of the vehicle and the acceleration and deceleration. Therefore, when the maximum regenerative power is changed, by considering the speed of the vehicle in the range of change of the braking torque before and after the change, the range of change of the stimulus value accepted by the user in the medium and high speed range can be determined. And, by determining the range of change of the maximum braking torque based on the range of change of the determined stimulus value, the range of change of the stimulus value accepted by the user in the low speed range can be made consistent or similar to the range of change of the stimulus value accepted by the user in the medium and high speed range. Thus, before and after the maximum regenerative power is changed, the impression received by the user in the regenerative braking of the vehicle can be made consistent or similar.

[0025] In the above-mentioned embodiment, the change range of the stimulus value accepted by the user according to the change range of the maximum regenerative power may be equal to the change range of the stimulus value accepted by the user according to the change range of the maximum braking torque. In addition, the "equal" mentioned here is not limited to being completely equal, and there may be a deviation in a range that the user cannot perceive, such as a deviation within 15%.

[0026] In one embodiment of the present technology, the control device may be capable of changing the maximum braking torque regardless of whether the maximum regenerative power is changed or not. In other words, the control device may change only the maximum braking torque according to various conditions and requirements.

[0027] In the above-mentioned embodiment, the control device may determine the change range of the stimulus value accepted by the user before and after the change when the maximum braking torque is changed, and set a limit on the braking torque in each vehicle speed range according to the change range of the determined stimulus value. According to such a structure, the impression received by the user in the regenerative braking of the vehicle can be made consistent or similar before and after the maximum braking torque is changed.

[0028] In the above-mentioned embodiment, the control device may change the maximum braking torque according to the properties of the road surface on which the vehicle is traveling. According to such a structure, when the vehicle is traveling on a road surface with a low friction coefficient such as a snowy road surface, the maximum braking torque can be set to a lower value, thereby achieving stable driving of the vehicle. In addition, when the maximum braking torque is set to a lower value, by also setting limits on the braking torque in each vehicle speed range, it is also possible to suppress the discomfort caused to the user.

[0029] The electric vehicle 10 of the embodiment will be described with reference to the accompanying drawings. The electric vehicle 10 is a so-called automobile, which is a vehicle that travels on the road. Figure 1 As shown, the electric vehicle 10 includes a body 12, a plurality of wheels 14f, 14r, and a plurality of side doors 16, 18. The body 12 is not particularly limited and is mainly made of metal. A cab 12c is provided inside the body 12. The cab 12c is configured to accommodate one or more users. A pedal device 26 operated by the user is provided in the cab 12c.

[0030] The plurality of wheels 14f, 14r are rotatably supported by the vehicle body 12, respectively. The plurality of wheels 14f, 14r include a pair of front wheels 14f located at the front portion of the vehicle body 12 and a pair of rear wheels 14r located at the rear portion of the vehicle body 12. The pair of front wheels 14f are coaxially arranged at the front portion of the vehicle body 12. The pair of rear wheels 14r are coaxially arranged at the rear portion of the vehicle body 12. The pair of front wheels 14f are steering wheels whose direction of the rotation axis changes. The pair of rear wheels 14r are driving wheels driven by the motor (M) 20. In addition, the number of wheels 14f, 14r is not limited to four.

[0031] like Figure 1 , Figure 2 As shown, the electric vehicle 10 also includes an electric motor 20, a power conversion unit 22, a battery pack 24, and an electronic control unit (ECU) 30. The electric motor 20 is a running electric motor that drives a pair of rear wheels 14r and is mechanically connected to the pair of rear wheels 14r. The battery pack 24 is a power supply device that supplies power to the electric motor 20 and is electrically connected to the electric motor 20 via the power conversion unit 22. The battery pack 24 has a plurality of secondary battery cells built in, and is configured to be repeatedly charged by power supplied from the outside and regenerative power generated by the electric motor 20. As an example, the power conversion unit 22 has a DC-DC converter (DC-DC) 22a and an inverter (INV) 22b.

[0032] The electronic control unit 30 is connected to the power conversion unit 22, the battery pack 24, and the pedal device 26 so as to be communicable, and monitors and / or controls the operation of the power conversion unit 22, the battery pack 24, and the pedal device 26. For example, the electronic control unit 30 controls the operation of the power conversion unit 22 according to the user's operation of the pedal device 26. Thus, for example, when the user steps on the pedal device 26, the driving power is supplied from the battery pack 24 to the motor 20, and the pair of rear wheels 14r are driven by the motor 20. On the other hand, when the user releases his foot from the pedal device 26, the regenerative power is supplied from the motor 20 to the battery pack 24, and the pair of rear wheels 14r are regeneratively braked by the motor 20.

[0033] The electric motor 20 is not limited to driving a pair of rear wheels 14r, as long as it is configured to drive at least one of the multiple wheels 14f, 14r. In addition to the electric motor 20, the electric vehicle 10 may also have other prime movers such as an engine. In addition, in addition to the battery pack 24, the electric vehicle 10 may also have other power supply devices such as a fuel cell unit and a solar panel. That is, the electric vehicle 10 is not limited to a rechargeable electric vehicle, but may also be a hybrid vehicle, a fuel cell vehicle, a solar car, etc. In addition, the electric vehicle 10 of this embodiment is not limited to a vehicle driven by a user, but also includes a vehicle operated by an external device and a vehicle in which the electric vehicle 10 drives autonomously.

[0034] The electronic control unit 30 in this embodiment is an example of a control device for controlling regenerative braking using the electric motor 20. As indicators for controlling regenerative braking, the electronic control unit 30 stores a maximum braking torque and a maximum regenerative power. The maximum braking torque is a limit value (upper limit value) of the braking torque in regenerative braking, and is an indicator for preventing the braking torque from becoming too large. The maximum regenerative power is a limit value (upper limit value) of the regenerative power in regenerative braking, and is an indicator for preventing the regenerative power supplied to the battery pack 24 from becoming too large. The electronic control unit 30 controls the regenerative braking using the electric motor 20 in such a way that the braking torque is less than the maximum braking torque and the regenerative power is less than the maximum regenerative power.

[0035] like Figure 3 As shown, when the speed of the electric vehicle 10 is in the middle and high speed range A, before the braking torque (X) reaches the maximum braking torque (Tx), the regenerative power is made to reach the maximum regenerative power, thereby limiting the regenerative braking using the motor 20. On the other hand, when the speed of the electric vehicle 10 is reduced to the low speed range B, before the regenerative power reaches the maximum regenerative power, the braking torque is made to reach the maximum braking torque (Tx), thereby limiting the regenerative braking using the motor 20. As a result, there may be a difference in the braking torque actually generated between the middle and high speed range A and the low speed range B, but the difference is relatively small.

[0036] Here, regarding the maximum regenerative power, for example, its setting value may be changed according to the charging rate or temperature of the battery pack 24. Thus, for example, the degradation of the battery pack 24 can be suppressed. In the electronic control unit 30 in the present embodiment, the maximum regenerative power is changed according to the charging rate of the battery pack 24. Specifically, when the charging rate of the battery pack 24 exceeds a predetermined threshold value, the electronic control unit 30 is configured to limit the regenerative power supplied to the battery pack 24 by reducing the maximum regenerative power. That is, in normal times, a first value is used as the maximum regenerative power, and when the restriction is activated, a second value lower than the first value is used as the maximum regenerative power.

[0037] like Figure 4 As shown, when the maximum regenerative power is reduced compared to normal, in the medium and high speed range A, the regenerative braking is further limited, so that the actually generated braking torque (Y) is further reduced. In contrast, in a part of the low speed range B, even if the maximum regenerative power is set lower than normal, the regenerative braking is not limited thereby. As a result, assuming that only the maximum regenerative power is changed and the maximum braking torque (Tx) is maintained, there will be a large change between the medium and high speed range A and the low speed range B due to the actually generated braking torque. Such a behavior of the electric vehicle 10 that is different from normal times may cause discomfort to the user riding the electric vehicle 10.

[0038] In view of the above problem, the electronic control unit 30 in this embodiment is configured to change the maximum braking torque (from Figure 4 Thus, when the maximum regenerative power is changed, the braking torque actually generated in the low speed range B can also change in accordance with the change of the braking torque actually generated in the medium and high speed range A. The change of the braking torque actually generated from the medium and high speed range A to the low speed range B can be made consistent or similar before and after the maximum regenerative power is changed, which can suppress the discomfort caused to the user and appropriately limit the regenerative braking of the electric vehicle 10.

[0039] Although not particularly limited, the electronic control unit 30 may be configured to determine the change range when changing the maximum braking torque according to the change range when changing the maximum regenerative power. In this case, the stimulus value γ accepted by the user accompanying the acceleration and deceleration of the electric vehicle 10 may be considered. Figure 5As shown, with respect to the acceleration and deceleration of the electric vehicle 10, the stimulus value γ accepted by the user changes according to the combination of the speed of the electric vehicle 10 and the acceleration and deceleration. Therefore, when the regenerative braking of the electric vehicle 10 is implemented, the stimulus value γ accepted by the user also changes all the time during the process of the speed of the electric vehicle 10 changing from the medium-high speed range A to the low-speed range B. When the change amplitude Δγ of the stimulus value γ accepted by the user during the regenerative braking is different before and after the maximum regenerative power is changed, that is, when it is different between normal time and limited time, the user may feel uncomfortable. Therefore, in the case of changing the maximum braking torque according to the change of the maximum regenerative power, before and after the change, instead of just making the deviation of the braking torque generated between the medium-high speed range A and the low-speed range B consistent, the change amplitude Δγ of the stimulus value γ accepted by the user is made consistent or approximate.

[0040] Reference Figure 6 , an example of a control method for changing the maximum regenerative power and the maximum braking torque in consideration of the stimulus value γ as described above is described. First, in step S12, the electronic control unit 30 obtains the charging rate of the battery pack 24. Next, in step S14, the electronic control unit 30 determines whether it is necessary to change the maximum regenerative power based on the charging rate of the battery pack 24. When the electronic control unit 30 determines that a change in the maximum regenerative power is not required ("No" in step S14), the electronic control unit 30 returns to the processing of step S12. On the other hand, when the electronic control unit 30 determines that a change in the maximum regenerative power is required ("Yes" in step S14), the electronic control unit 30 enters the processing of step S16.

[0041] In step S16, the electronic control unit 30 estimates the acceleration in the front-rear direction generated by the electric vehicle 10 based on the changed maximum regenerative power. Here, since the electric vehicle 10 is regeneratively braked, the estimated acceleration becomes a negative value. Next, in step S18, the electronic control unit 30 calculates the stimulus value γ accepted by the user using the estimated acceleration and the speed of the electric vehicle 10. In order to estimate the stimulus value γ, the electronic control unit 30 may also store, for example, Figure 5 Next, in step S20 , the electronic control unit 30 calculates the change width Δγ of the stimulus value γ from normal times, that is, the change width Δγ of the stimulus value γ before and after the maximum regenerative power is changed.

[0042] Next, in step S22, the electronic control unit 30 calculates the change range of the maximum braking torque based on the calculated change range Δγ of the stimulus value γ. Specifically, the electronic control unit 30 calculates the change range of the maximum braking torque in such a way that the change range Δγ of the stimulus value γ before and after the change of the maximum braking torque is equal to the change range Δγ of the stimulus value γ calculated in step S20. Finally, in step S24, the electronic control unit 30 uses the calculated change range of the maximum braking torque to change the maximum braking torque.

[0043] As described above, when the maximum regenerative power is changed, the electronic control unit 30 can determine the change range Δγ of the stimulus value γ accepted by the user before and after the change, and determine the change range for changing the maximum braking torque based on the determined change range Δγ of the stimulus value γ. Thus, before and after the change of the maximum regenerative power, the change range Δγ of the stimulus value γ accepted by the user can be made consistent or approximate. Therefore, the discomfort caused to the user can be effectively suppressed, and the regenerative braking of the electric vehicle 10 can be appropriately restricted.

[0044] Although not particularly limited, the electronic control unit 30 in this embodiment may also change the maximum braking torque regardless of whether the maximum regenerative power is changed or not. For example, the electronic control unit 30 may also change the maximum braking torque according to the properties (particularly the friction coefficient) of the road surface on which the electric vehicle 10 is traveling. According to such a structure, when the electric vehicle 10 is traveling on a road surface with a low friction coefficient such as a snowy road surface, for example, by setting the maximum braking torque to a low level, the electric vehicle 10 can be driven stably.

[0045] When changing the maximum braking torque, the electronic control unit 30 can also take into account the stimulus value γ accepted by the user, similar to the aforementioned change in the maximum regenerative power. In this case, the electronic control unit 30 can also determine the change range Δγ of the stimulus value γ accepted by the user before and after the change when changing the maximum braking torque, and set limits on the braking torque in each vehicle speed range based on the determined change range Δγ of the stimulus value γ. Thus, before and after changing the maximum braking torque, the change range Δγ of the stimulus value γ accepted by the user can be made consistent or approximate. That is, the discomfort caused to the user can be suppressed.

[0046] Reference Figure 7, an example of a control method for changing the maximum braking torque in consideration of the stimulus value γ as described above is described. First, in step S32, the electronic control unit 30 estimates the friction coefficient of the road surface on which the electric vehicle 10 is traveling. This estimation can be estimated, for example, based on the relationship between the torque output by the motor 20 and the acceleration generated in the electric vehicle 10. Next, in step S34, the electronic control unit 30 determines whether the road surface on which the electric vehicle 10 is traveling belongs to a predetermined road surface with a low friction coefficient based on the estimated friction coefficient. When the electronic control unit 30 determines that the road surface does not belong to a road surface with a low friction coefficient ("No" in step S34), the electronic control unit 30 returns to the processing of step S32. On the other hand, when the electronic control unit 30 determines that the road surface belongs to a road surface with a low friction coefficient ("Yes" in step S34), the processing enters step S36.

[0047] In step S36, the electronic control unit 30 estimates the maximum acceleration in the forward and backward directions allowed by the electric vehicle 10 based on the estimated friction coefficient of the road surface. Here, since the electric vehicle 10 is regeneratively braked, the estimated maximum acceleration becomes a negative value. Next, in step S38, the electronic control unit 30 uses the estimated maximum acceleration and the speed of the electric vehicle 10 to calculate the stimulus value γ accepted by the user. Next, in step S40, the electronic control unit 30 calculates the change range Δγ of the stimulus value γ from the normal time, that is, the change range Δγ of the stimulus value γ before and after the change of the maximum acceleration.

[0048] Next, in step S42, the electronic control unit 30 calculates the change range of the braking torque in each speed range (particularly the medium and high speed range A) based on the calculated change range Δγ of the stimulus value γ. Specifically, the electronic control unit 30 calculates the change range of the braking torque in each speed range in such a way that the change range Δγ of the stimulus value γ when the braking torque is changed in each speed range is equal to the change range Δγ of the stimulus value γ calculated in step S40. Finally, in step S44, the electronic control unit 30 sets a limit on the braking torque in each speed range using the calculated change range of the braking torque.

[0049] As described above, the electronic control unit 30 can change the maximum braking torque in regenerative braking, for example, when the electric vehicle 10 is traveling on a road surface with a low friction coefficient such as a snowy road surface, and set a limit on the braking torque in each speed range that takes into account the stimulus value γ accepted by the user. As a result, before and after the change of the maximum braking torque, the impression accepted by the user in the regenerative braking of the electric vehicle 10 can be made consistent or similar. That is, it is possible to suppress the discomfort caused to the user and set an appropriate limit on the braking torque in regenerative braking.

[0050] The above describes the implementation methods of the present technology in detail, but these are only examples and do not limit the claims. The technology described in the claims includes technologies obtained by various deformations and changes to the specific examples illustrated above. The technical elements described in this specification or the drawings exert technical usefulness alone or in various combinations, and are not limited to the combinations described in the claims at the time of application. In addition, the technology illustrated in this specification or the drawings achieves multiple purposes at the same time, and achieving one of the purposes itself has technical usefulness.

Claims

1. An electric vehicle, characterized in that include: an electric motor connected to the wheels and configured to perform regenerative braking on the wheels; a battery configured to store regenerative power output by the electric motor through the regenerative braking; and a control device configured to control the regenerative braking so that the braking torque applied to the wheels is less than the maximum braking torque and the regenerative electric power output by the electric motor is less than the maximum regenerative electric power, The control device is configured to be able to change the maximum regenerative power, and when the maximum regenerative power is changed, the maximum braking torque is also changed. The control device is configured to determine a change range of a stimulus value accepted by a user before and after the change when the maximum regenerative power is changed, and determine a change range when changing the maximum braking torque based on the determined change range of the stimulus value.

2. The electric vehicle according to claim 1, characterized in that: The control device is configured to change the maximum regenerative power according to a charge rate or a temperature of the battery.

3. The electric vehicle according to claim 1 or 2, characterized in that: The change range of the stimulus value accepted by the user according to the change range of the maximum regenerative electric power is equal to the change range of the stimulus value accepted by the user according to the change range of the maximum braking torque.

4. The electric vehicle according to claim 1 or 2, characterized in that: The control device can change the maximum braking torque regardless of whether the maximum regenerative electric power is changed or not.

5. The electric vehicle according to claim 4, characterized in that: The control device is configured to determine a change range of a stimulus value accepted by a user before and after the change when the maximum braking torque is changed, and to set a limit on the braking torque in each vehicle speed range according to the determined change range of the stimulus value.

6. The electric vehicle according to claim 4, characterized in that: The control device is configured to change the maximum braking torque according to the properties of a road surface on which the electric vehicle is traveling.

7. The electric vehicle according to claim 5, characterized in that: The control device is configured to change the maximum braking torque according to the properties of a road surface on which the electric vehicle is traveling.

8. An electric vehicle, characterized in that include: an electric motor connected to the wheels and configured to perform regenerative braking on the wheels; a battery configured to store regenerative power output by the electric motor through the regenerative braking; and a control device configured to control the regenerative braking so that the braking torque applied to the wheels is less than the maximum braking torque and the regenerative electric power output by the electric motor is less than the maximum regenerative electric power, The control device is configured to be able to change the maximum regenerative power, and when the maximum regenerative power is changed, the maximum braking torque is also changed. The control device is capable of changing the maximum braking torque regardless of whether the maximum regenerative power is changed or not. The control device is configured to determine a change range of a stimulus value accepted by a user before and after the change when the maximum braking torque is changed, and to set a limit on the braking torque in each vehicle speed range according to the determined change range of the stimulus value.

9. The electric vehicle according to claim 8, characterized in that: The control device is configured to change the maximum braking torque according to the properties of a road surface on which the electric vehicle is traveling.

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