JP2001037010A - Motor-driven vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain the performance of a battery at a high level without using heat insulating devices nor cooling devices. SOLUTION: A temperature sensor 31 is installed to a battery 25 which supplies electricity to a motor 3 for driving wheels. A generator 22 connected to the motor 3 and battery 25 is controlled by means of an integral controller 27. The controller 27 is set to relatively lower the generated output of the generator 22 when the temperature of the battery 25 detected by means of the temperature sensor 31 is relatively low and to increase the generated output of the generator 22, when the temperature of the battery 25 is relatively high.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric vehicle having a generator connected to a wheel driving motor and a battery.

[0002]

2. Description of the Related Art Conventionally, as an electric vehicle in which wheels are driven by a motor, there is a vehicle equipped with a generator so that a battery for supplying power to the motor can be charged while traveling. This type of electric vehicle employs a structure in which charging by the generator is started when the remaining capacity of the battery reaches a predetermined lower limit, and the charging is stopped when the remaining capacity reaches the upper limit. I have.

[0003]

However, in the conventional electric vehicle configured as described above, the temperature of the battery is a problem. This is because the input / output characteristics of the battery change according to the temperature. That is, when the battery temperature is relatively low, the output performance decreases, and when the battery temperature is high, the input performance (charging efficiency) decreases.

[0004] In order to maintain high performance even when the battery temperature changes, a heat retention device for keeping the battery warm,
It is conceivable to provide a cooling device for cooling the battery. However, the provision of such a heat retaining device or cooling device increases the number of parts and increases the weight of the vehicle.

The present invention has been made to solve such a problem, and an object of the present invention is to make it possible to keep the performance of a battery high without using a warming device or a cooling device.

[0006]

In order to achieve this object, an electric vehicle according to the present invention is provided with a temperature sensor in a battery for supplying power to a wheel driving motor, and controls a generator connected to the motor and the battery. Power generation control device,
When the battery temperature detected by the temperature sensor is relatively low, the generated power amount of the generator is relatively reduced, and when the battery temperature is relatively high, the generated power amount is relatively increased. Things.

According to the present invention, when the battery temperature is relatively low, power is easily supplied from the battery to the motor, and the battery temperature rises due to the temperature rise due to discharge. Also, when the battery temperature is relatively high, power is easily supplied from the generator to the motor,
Temperature rise due to battery discharge is suppressed.

According to a second aspect of the present invention, in the electric vehicle according to the first aspect, the power generation control device further includes a remaining capacity detection unit that detects a remaining capacity of the battery. When the remaining capacity of the battery detected by the remaining capacity detecting means is relatively small, the amount of power generated by the generator is relatively increased.

According to the present invention, when the remaining capacity of the battery is relatively small and the battery temperature is relatively low, the battery can be sufficiently charged, and when the battery temperature is relatively high. Thereby, the discharge of the battery is further suppressed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an embodiment of an electric vehicle according to the present invention will be described in detail with reference to FIGS.
Here, a description will be given of a form adopted when the present invention is applied to an electric assist bicycle. FIG. 1 is a configuration diagram of an electric vehicle according to the present invention, FIG. 2 is a block diagram schematically showing the configuration of the electric vehicle according to the present invention, FIG. 3 is a circuit diagram thereof, and FIG. FIG. 5 is a graph showing the relationship between the battery temperature and the throttle opening.

In these figures, the reference numeral 1 indicates an electric assist bicycle according to this embodiment. The electrically assisted bicycle 1 has a structure that can adopt a form in which the rear wheel 2 is driven only by human power and a form in which the rear wheel 2 is driven by the combined force of the motor power and human power indicated by reference numeral 3 in FIG. The human power and the power of the motor 3 are transmitted to a rear wheel 2 via a drive shaft 6 from a resultant shaft (not shown) of a power unit 5 mounted below the saddle 4.

The power unit 5 rotatably supports a pedal crankshaft 9 having a pedal 7 and a crank 8, and also supports the motor 3, and detects the magnitude of human power as shown in FIG. Detector 10 for
And a motor controller 11 for controlling the power of the motor 3 and a vehicle speed sensor 12 for detecting the vehicle speed.

The motor controller 11 employs a circuit for controlling the power of the motor 3 so as to be substantially proportional to the magnitude of the human power detected by the torque detector 10. Also,
The motor controller 11 employs a circuit that cuts off power supply to the motor 3 at a high speed when the vehicle speed detected by the vehicle speed sensor 12 exceeds a predetermined value.

The engine 2 is located behind the power unit 5.
1 and a generator 22, and a battery 25 for supplying power to the motor 3 is mounted on a down tube 24 of the body frame 23 in front of the power unit 5.

The engine 21 is a two-cycle air-cooled single-cylinder engine, and has a structure for driving a motor generator 26 of a generator 22 as shown in FIG. The throttle valve 21a of the engine 21 has a structure driven by an actuator (not shown). This actuator is controlled by an integrated controller indicated by reference numeral 27 in FIG. The engine 21 is started by the motor generator 26 using the crankshaft 21 of the engine 21.
b, and the stop of the engine 21 is performed by the integrated controller 27 opening the ignition circuit.

The generator 22 comprises a motor generator 26 and a motor generator controller 28. The motor generator 26 has both functions of a motor and a generator,
It is used as a motor when starting the engine 21 and as a generator when generating power. When used as a generator, a structure is employed in which power is generated with a generated power amount substantially proportional to the rotation speed of the engine 21.

The motor / generator controller 28 is connected to the integrated control controller 27 and controls the engine 21 based on a control signal sent from the integrated control controller 27.
And a circuit that controls the start / stop of the motor and supplies the power generated by the motor generator 26 to the power unit 5 and the battery 25.

As shown in FIGS. 2 and 3, the battery 25 includes a number of battery cells 29, a battery fuel gauge 30, and a temperature sensor 31 for detecting the temperature of the battery cells 29. .

The battery cell 29 is composed of a well-known Ni-MH unit cell or Ni-Cd unit cell, which are connected in series. The input / output characteristics of the battery cell 29 are as shown in FIG. Here, the input / output characteristics of the battery cell 29 will be described.

The horizontal axis of FIG. 4 shows the state of charge of the battery 25 {the remaining capacity SOC (%)}, and the vertical axis shows the output / input power (W). Win on the vertical axis indicates electric power (required input) supplied from the generator 22 to the battery 25, and Wout indicates electric power (required output) required to drive the motor 3. Also, in FIG.
5 shows the input characteristics at a low temperature by a curve A, and the output characteristics by a curve B. The input characteristics at room temperature are shown by a curve C, and the output characteristics at room temperature are shown by a curve D. Further, the input characteristics at a high temperature are indicated by a curve E, and the output characteristics at a high temperature are indicated by a curve F.

Curves A, C, and C showing input characteristics (charging characteristics)
E indicates that relatively large power can be charged when the remaining capacity is small, and that the chargeable power gradually decreases as the remaining capacity increases. Also, it shows that the chargeable power increases as the battery temperature decreases. Curves B, D, and F showing output characteristics (discharge characteristics) show that when the remaining capacity is small, the output power is relatively small, and the output power gradually increases as the remaining capacity increases. It also shows that the output power increases as the battery temperature increases.

In the battery 25 having such characteristics, when the input power Win and the output power Wout are the values shown in FIG. 2, the output power becomes insufficient when the remaining capacity falls below the SOC1 near the lower limit at normal temperature. The remaining capacity is SO
If it exceeds C4, the input power becomes insufficient. That is, at normal temperature, the range of the available remaining capacity SOC is between SOC1 near the lower limit and SOC4 near the upper limit.

At low temperatures, if the remaining capacity falls below SOC2, the output power becomes insufficient, and charging is possible even when the remaining capacity reaches the upper limit value.
The range of OC falls between SOC2 and the upper limit. That is, at low temperatures, if the remaining capacity is small, the output power becomes insufficient.

Further, at a high temperature, the output power does not run short even if the remaining capacity reaches the lower limit, and the remaining capacity becomes S
If the input power exceeds OC3, the input power becomes insufficient.
Between. That is, at high temperatures, if the remaining capacity is large, the input power becomes insufficient.

The battery fuel gauge 30 is for detecting the remaining capacity of the battery 25. The battery fuel gauge 30 includes an ammeter 32 and a voltmeter 33. A circuit for detecting the voltage is adopted. Each detection value is sent to the integrated controller 27.

The integrated controller 27 controls charging and discharging of the battery 25 and the rotation speed of the engine 21 (the generator 22).
As shown in FIG. 3, a battery temperature detecting means 41 for detecting a battery temperature based on an output value of the temperature sensor 31 and a battery fuel gauge 30 as shown in FIG. The engine includes a remaining capacity detecting unit 42 for obtaining a remaining capacity of the battery 25 based on the detected discharge current value, charging current value and voltage, and a throttle control unit 43 for controlling an actuator for driving a throttle valve of the engine 21. This integrated controller 2
7 constitutes a power generation control device according to the present invention.

When the remaining capacity obtained by the remaining capacity detecting means 42 falls below a predetermined lower limit, the throttle control means 43 starts the engine 21 to start the electric power generation by the generator 22. A circuit for stopping the engine 21 and stopping the power generation by the generator 22 when a predetermined upper limit is reached is employed. That is, when the remaining capacity of the battery 25 falls below the lower limit value, the engine 21 generates the generator 22 until the remaining capacity reaches the upper limit value.
To drive the battery 25 with the power generated by the generator 22.
Charge.

The throttle control means 43 controls the throttle valve 21a during charging as described below. That is,
When the battery temperature detected by the temperature sensor 31 is relatively low, the throttle valve opening of the engine 21 is relatively reduced, and the amount of power generated by the generator 22 is relatively reduced. When the battery temperature is relatively high, the throttle valve opening is relatively increased to increase the
Relatively increases the amount of generated power. Further, when the remaining capacity of the battery 25 detected by the remaining capacity detecting means 42 is relatively small, the above-described throttle control corresponding to the battery temperature is performed with the throttle opening relatively increased.

When the remaining capacity of the battery 25 is smaller than the lower limit value, the throttle control means 43 sets the throttle opening to a predetermined maximum opening irrespective of the battery temperature. When the value exceeds the value but does not reach the upper limit, the throttle opening is set to the minimum chargeable opening.

Next, the operation of the integrated controller 27 will be described in detail with reference to FIG. When the state of charge SOC of the battery 25 is smaller than the lower limit SOCLL, FIG.
As shown by a solid line Th1, the throttle opening is set to a predetermined maximum opening. When the battery 25 is in such a state, the throttle opening is kept constant regardless of the battery temperature.

The remaining capacity of the battery 25 is lower than the lower limit SOC.
When it is larger than LL and equal to or less than the intermediate value SOCm, the throttle opening is controlled in accordance with the battery temperature as shown by a solid line Th2. That is, as the battery temperature increases, the throttle opening is gradually increased, and the amount of power generated by the generator 22 is increased.

The remaining capacity of the battery 25 is the intermediate value SOC.
m, the charging stop value SOC near the upper limit
When the throttle opening is equal to or less than UL, the throttle opening is controlled in accordance with the battery temperature in a state where the throttle opening is relatively small, as shown by a solid line Th3. That is,
While the throttle opening is set lower than when the throttle control indicated by the solid line Th2 is performed, the throttle opening is gradually increased as the battery temperature increases.

The remaining capacity of the battery 25 is the charge stop value S
When it is larger than OCUL, the throttle opening is set to the minimum chargeable opening as shown by the solid line Th4.
When charging proceeds in this state and the remaining capacity reaches the upper limit, the engine 21 is stopped.

The electric assisted bicycle 1 configured as described above
In the case, when the battery temperature detected by the temperature sensor 31 is relatively low, the throttle opening of the engine 21 is reduced to relatively reduce the amount of power generated by the generator 22, so that the battery 25 discharges more than the charged amount. The amount is larger, and electric power is easily supplied from the battery 25 to the motor 3. For this reason, when the battery temperature is relatively low, the battery temperature rises due to the temperature rise due to discharge.

On the other hand, when the battery temperature is relatively high, the throttle opening of the engine 21 is increased and the
Since the amount of generated power of the power generator 2 is relatively increased, power is easily supplied from the generator 22 to the motor 3. Therefore, when the battery temperature is relatively high, the temperature rise due to the discharge of the battery 25 is suppressed.

Therefore, the temperature of the battery 25 can be maintained at an appropriate temperature without using a warming device or a cooling device.

When the remaining capacity of the battery 25 is relatively small, the throttle opening of the engine 21 is increased to relatively increase the amount of power generated by the generator 22. When the battery temperature is relatively low and the battery temperature is relatively low, the battery 25 can be sufficiently charged, and when the battery temperature is relatively high, the discharge of the battery 25 is further suppressed. .

Therefore, even if the remaining capacity of the battery 25 is small, the vehicle can travel without being adversely affected by the battery temperature.

In this embodiment, an example in which the present invention is applied to an electric assisted bicycle is shown.
The present invention can also be applied to other electric vehicles such as electric motorcycles and electric vehicles that run only with the power of.

The power source for charging the battery may be a fuel cell that generates power using, for example, hydrogen and atmospheric oxygen, instead of employing a structure using an engine and a generator.

[0041]

As described above, according to the present invention, when the battery temperature is relatively low, the battery 25
, Power is easily supplied to the motor 3 and the battery temperature rises due to the temperature rise due to the discharge. When the battery temperature is relatively high, the generator 22
Since the power is easily supplied to the battery 25, the temperature rise due to the discharge of the battery 25 is suppressed.

Therefore, the temperature of the battery 25 can be maintained at an appropriate temperature without using a warming device or a cooling device, and the performance of the battery 25 can be kept high.

According to the second aspect of the present invention, when the remaining capacity of the battery 25 is relatively small and the battery temperature is relatively low, the battery 25 can be charged sufficiently, Is relatively high, the discharge of the battery 25 is further suppressed.

Therefore, even if the remaining capacity of the battery 25 is small, the vehicle can travel without being adversely affected by the battery temperature.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of an electric vehicle according to the present invention.

FIG. 2 is a block diagram schematically showing a configuration of an electric vehicle according to the present invention.

FIG. 3 is a circuit diagram showing a configuration of an electric vehicle according to the present invention.

FIG. 4 is a graph showing a relationship between a charge state of a battery and charge / discharge power.

FIG. 5 is a graph showing a relationship between a battery temperature and a throttle opening.

[Explanation of symbols]

1: electric assist bicycle, 3: motor, 21: engine, 2
2 ... generator, 25 ... battery, 27 ... integrated controller, 41 ... battery temperature detection means, 42 ... remaining capacity detection means, 43 ... throttle control means.

Claims (2)

[Claims] 1. An electric vehicle comprising: a motor for driving wheels; a battery for supplying power to the motor; a generator connected to the motor and the battery; and a power generation control device for controlling the generator. The battery is provided with a temperature sensor, and the power generation control device relatively reduces the amount of power generated by the generator when the battery temperature detected by the temperature sensor is relatively low, and the battery temperature is relatively low. An electric vehicle characterized in that the power generation amount is relatively increased when the power is high. 2. The electric vehicle according to claim 1, wherein the power generation control device includes a remaining capacity detection unit that detects a remaining capacity of the battery, and the power generation control device controls the remaining capacity of the battery detected by the remaining capacity detection unit. An electric vehicle, wherein the amount of power generated by a generator is relatively increased when the power is relatively small.