JP7192365B2 - battery-powered industrial vehicle - Google Patents

Description

The present invention relates to battery powered industrial vehicles.

Battery-powered industrial vehicles such as battery forklifts may be equipped with a lithium-ion battery device. In a general lithium ion battery device, the possibility of failure of the battery included in the lithium ion battery device increases at high temperatures. In addition, a general lithium-ion battery device is packaged with a built-in lithium-ion battery and a controller. When the controller detects a temperature rise exceeding the threshold value of the lithium-ion battery, the input/output of the lithium-ion battery device is switched off. Cut off.

However, if a temperature rise exceeding the threshold value of the lithium-ion battery device is detected during work while the battery-powered industrial vehicle is in operation, the input/output of the lithium-ion battery device is cut off and the battery-powered industrial vehicle cannot be used. Work with industrial vehicles is suspended. Therefore, a display device is installed near the driver's seat of the battery-powered industrial vehicle, and before the input/output of the lithium-ion battery device is cut off, the display device warns the operator that the input/output is about to be cut off. is notified to

On the other hand, as a conventional technology related to battery-powered industrial vehicles, for example, a battery control device disclosed in Patent Document 1 is known. In the battery control device disclosed in Patent Document 1, the output from the battery is controlled based on the battery temperature, the state of charge (SOC) of the battery, and the required output of the motor. If the battery temperature is equal to or higher than the threshold temperature, the battery is in a high temperature state and there is a possibility of battery failure. For this reason, the output control means performs output suppression to suppress the output from the battery, and controls the output from the battery so as to be limited within the performance range of the battery. Further, as another conventional technology, a control device for an electric vehicle disclosed in Patent Document 2 is known.

JP 2015-118789 A JP 2011-239629 A

However, even if the warning that the input/output is about to be cut off is displayed on the display device provided near the driver's seat, the operator who is concentrating on the work may not notice the warning. Therefore, it is desired that the operator can more reliably recognize that the shutdown state due to the temperature rise of the lithium ion battery device is imminent. In addition, even if work is interrupted before the lithium battery device shuts down due to a rise in temperature, if the battery is charged while the temperature has risen after that, the temperature of the battery will rise further and charging will be shut down. be.

Further, in the battery control device described in Patent Document 1, only the output of the battery is limited at high temperatures, but it is unclear how to specifically limit the output of the battery. Also, no consideration is given to the temperature rise of the battery due to regeneration or charging. On the other hand, the control device for an electric vehicle described in Patent Document 2 abruptly limits the discharge current in the high temperature range of the battery. There is a risk that the work inherent in industrial vehicles will be suddenly interrupted. Also, in a high temperature range, the discharge current is limited before the charge current, so there is a risk that the desired braking force will be insufficient during braking by regeneration.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to reduce the frequency of input/output cutoff due to a temperature rise in a battery device, and to reduce the possibility of a cutoff due to a temperature rise. To provide a battery-powered industrial vehicle in which an operator can surely recognize

In order to solve the above-described problems, the present invention provides a drive motor, a battery device that outputs power when the drive motor is driven and receives power when the drive motor is regenerated, Battery temperature detecting means for detecting the temperature of the battery provided in the battery device, and an accelerator sensor for acquiring the operation direction and operation amount of the accelerator lever are connected, and according to the operation amount of the accelerator lever acquired by the accelerator sensor. and a control device for controlling the drive motor so that the running speed of the battery-powered industrial vehicle is equal to or higher than a preset limit for the temperature of the battery detected by the battery temperature detection means. When the first high temperature state is equal to or higher than the starting temperature and less than the usable upper limit temperature , the output of the drive motor is restricted according to the temperature of the battery, and when the first high temperature state is reached, the temperature of the battery an upper limit value of the output of the drive motor to be limited according to the temperature of the battery is controlled so as to be set to decrease stepwise as the temperature of the battery rises from the limit start temperature, and the temperature of the battery rises to the first high temperature state, the upper limit value of the output of the drive motor is set so that the boarding operator can feel the decrease in traveling speed and the slowness of acceleration, and the input/output of the battery device is cut off after a predetermined time. Predetermined temperatures corresponding to the temperatures of the plurality of batteries at the time of temperature rise, which are set by increasing the temperature by predetermined increments from the limit start temperature, so that it can be recognized that the battery is about to shut down before a warning is issued. It is characterized by a sequential decrease in multiple stages at a rate of

In the present invention, the output of the drive motor is limited according to the temperature of the battery when the temperature of the battery is in the first high temperature state equal to or higher than the preset limit start temperature. Therefore, the battery-powered industrial vehicle is operated while the output of the drive motor is limited. As a result, the operator can feel the limitation of the output of the drive motor from the operation of the battery-powered industrial vehicle, and can recognize that the battery is about to be cut off. In addition, by limiting the output of the drive motor before the battery disconnection state occurs, the operator can interrupt the work, and the frequency of the battery disconnection state can be reduced.
Further, when the battery is in the first high-temperature state, the upper limit value of the output of the drive motor to be limited according to the temperature of the battery is set so as to decrease stepwise as the temperature of the battery rises from the limitation start temperature. Therefore, the operation of the drive motor can be reduced step by step. The operator can feel that the operation of the drive motor is gradually lowered, and can recognize that the battery is about to be cut off.

In the battery-powered industrial vehicle described above, the output of the drive motor limited by the control device may be the number of revolutions of the drive motor or the torque of the drive motor.
In this case, when the temperature of the battery is in the first high temperature state equal to or higher than the limitation start temperature, the rotation speed or torque of the drive motor is limited according to the temperature of the battery. When the drive motor is the drive source for running, the running speed decreases or the acceleration slows down depending on the temperature of the battery. As a result, the operator can feel a decrease in running speed and slow acceleration, and can recognize that the battery is about to be cut off.

In the battery-powered industrial vehicle described above, the control device controls the temperature of the battery according to the temperature of the battery when the temperature of the battery detected by the battery temperature detection means is in a first high-temperature state equal to or higher than the limit start temperature. A configuration may be adopted in which the regenerative force generated by the regenerative operation of the drive motor is limited.
In this case, when the temperature of the battery is in the first high-temperature state equal to or higher than the limit start temperature, the regenerative power of the drive motor is limited according to the temperature of the battery. In the case where the drive motor is the drive source for running, the braking operation during braking of the battery-powered industrial vehicle is limited. As a result, the operator can feel the limitation of the braking operation during braking, and can recognize that the battery is about to be cut off.

Further, in the battery-powered industrial vehicle, the battery device detects that the temperature detected by the battery temperature detection means is equal to or higher than a specified temperature that is preset as a temperature higher than the restriction start temperature. cut off power output from and power input to the battery device;
A usable upper limit temperature higher than the restriction start temperature and lower than the specified temperature is set in advance in the control device, and the control device controls the temperature of the battery detected by the battery temperature detection means. When the temperature is in a second high temperature state from the usable upper limit temperature to the specified temperature, the upper limit value of the output of the drive motor, which is limited according to the temperature of the battery, is controlled to be set to the lowest upper limit value. It is good also as a structure which carries out.
In this case, a usable upper limit temperature that is higher than the restriction start temperature and lower than the specified temperature is set in advance. When the temperature of the battery is in the second high temperature state from the usable upper limit temperature or higher to the specified temperature, the upper limit value of the output of the drive motor, which is limited according to the battery temperature, is set to the lowest upper limit value, and the drive motor is operated. to drive. Thus, in the second high temperature condition, the operation of the drive motor of the battery powered industrial vehicle is maximally restricted. As a result, the operator can feel that the operation of the drive motor is maximally restricted, and can recognize that the battery is about to be cut off.

Further, in the battery-powered industrial vehicle described above, the control device may change the restriction start temperature based on the charging rate of the battery.
In this case, by changing the limit start temperature based on the battery charging rate, even if the battery is charged while the temperature is still rising, the temperature does not rise to the specified temperature at which the battery is cut off, depending on the characteristics of the battery. An appropriate limit start temperature can be set.

Further, in the battery-powered industrial vehicle, the control device is configured to lower the restriction start temperature when the charging rate of the battery is less than a preset threshold than when the charging rate of the battery is equal to or higher than the threshold. may be
In this case, when the battery charging rate is less than a preset threshold, the restriction start temperature and the usable upper limit temperature are set lower than when the battery charging rate is equal to or higher than the threshold. Therefore, the limitation of the output of the drive motor starts at a lower temperature than when the battery charging rate is equal to or higher than the threshold. As a result, even if the battery is charged while the temperature rises after the output of the drive motor is restricted, the battery does not rise to the specified temperature at which the battery is cut off. In other words, the battery will not be cut off due to rapid charging after work is interrupted.

According to the present invention, it is possible to provide a battery-powered industrial vehicle that reduces the frequency of occurrence of input/output cutoff due to temperature rise of the battery device and allows the operator to reliably recognize that the cutoff due to temperature rise is imminent.

1 is a side view of a reach-type forklift according to an embodiment of the present invention; FIG. 1 is a plan view of a reach-type forklift according to an embodiment of the present invention; FIG. 1 is a control block diagram of a reach-type forklift according to an embodiment of the present invention; FIG. 4 is a flowchart showing the procedure of warning processing when the temperature of the battery is high according to the embodiment of the present invention; FIG. 4 is a diagram showing an example of an upper limit number of revolutions of a traction motor according to battery temperature in a high temperature state; FIG. 10 is an explanatory diagram illustrating the relationship between the output of the driving motor and regeneration in switchback operation;

Hereinafter, a reach-type forklift (hereinafter simply referred to as "forklift") as a battery-powered industrial vehicle according to an embodiment of the present invention will be described with reference to the drawings. The terms "back and forth", "left and right", and "up and down" that specify directions are based on the condition that the operator of the forklift sits in the standing driver's seat and faces the forward side of the forklift.

As shown in FIG. 1, the forklift 10 has a vehicle body 11 and a cargo handling device 14 . As shown in FIGS. 1 and 2, a pair of left and right reach legs 12 are provided on the front portion of the vehicle body 11 of the forklift 10 . Front wheels 13L and 13R are supported at the tip of each reach leg 12, respectively. Only the left reach leg 12 and the left front wheel 13L are shown in FIG. A cargo handling device 14 is provided between both reach legs 12, and is supported so as to perform a reach operation in the longitudinal direction. The reach operation of the cargo handling device 14 is performed by operating a reach cylinder (not shown) provided at the rear portion of the vehicle body 11 .

The cargo handling device 14 includes an outer mast 15 supported by the left and right reach legs 12 and an inner mast 16 supported by the outer mast 15 so as to be able to move up and down. A lift support 17 is supported on the inner mast 16 so as to be able to move up and down. A pair of left and right forks 18 are supported on the front surface of the lift support 17 . The upper end of the fork 18 is pivotally supported on the lift support 17 so as to allow the fork 18 to tilt. Therefore, the fork 18 can tilt back and forth. A lift bracket 19 is provided above the fork 18 . A lift cylinder 20 for raising and lowering the inner mast 16 is fixed behind the outer mast 15 .

A drive unit 22 is provided on the left side of the rear portion of the vehicle body 11 . The drive unit 22 includes a driving motor 23 as a driving motor, and drive wheels 24 supported below the driving motor 23 via a speed reduction mechanism (not shown). The drive motor 23 drives the drive wheels 24 , and the forklift 10 runs on the road surface F by driving the drive wheels 24 . Further, the drive unit 22 is provided with a steering motor (not shown) for steering the drive wheels 24 . A standing driver's seat 25 as a driver's seat is provided on the rear right side of the vehicle body 11 . Caster wheels 26 are supported below the standing driver's seat 25 in the vehicle body 11 .

A floor switch 27 as boarding operator detection means is provided on the floor of the standing driver's seat 25 . The floor switch 27 is a switch for detecting the presence or absence of a boarding operator, and is turned on by the weight of the boarding operator when the boarding operator gets on the standing driver's seat 25 . A brake pedal 28 is provided on the floor of the standing driver's seat 25 . A brake pedal 28 is a brake pedal that releases braking when depressed. An accelerator lever 29, a lift lever 30, a reach lever 31, and a tilt lever 32 are provided in order from the right in the front part of the standing driver's seat 25. - 特許庁A steering wheel 33 with a steering knob is provided on the left side of the standing driver's seat 25 . 2, the accelerator lever 29, the lift lever 30, the reach lever 31, the tilt lever 32 and the steering wheel 33 are provided on the instrument panel 21 provided on the vehicle body 11. As shown in FIG. The instrument panel 21 is provided with a monitor 34 as a display device. Various information is displayed on the monitor 34 .

The accelerator lever 29 corresponds to accelerator operation means, and is used by the operator to instruct the forklift 10 to travel and stop, and is capable of instructing the traveling speed according to the operation state. When the operator does not touch the accelerator lever 29, the accelerator lever 29 is maintained in a substantially upright neutral state, and can be tilted forward from the neutral state or backward from the neutral state. Can be tilted.

The vehicle body 11 has pillars 35 and a head guard 36 . A pair of left and right pillars 35 are provided in the front portion of the vehicle body 11 , and the pair of left and right pillars 35 support a head guard 36 . The head guard 36 is provided above the standing driver's seat 25 and has a function of protecting a boarding operator on the standing driver's seat 25 .

As shown in FIG. 3 , the forklift 10 of this embodiment includes a battery device 40 , an inverter device 41 , a controller 42 , an accelerator sensor 43 and a monitor 34 .

The battery device 40 has a battery control device 45 and a battery 46 . The battery 46 has a cutoff switch 47 and a plurality of battery module units 48 . The battery module unit 48 includes a battery module 49 having a plurality of battery cells 50, a module controller 51 controlling the battery module 49, and a battery temperature detector 52 as battery temperature detection means for detecting the temperature of the battery module 49. there is The module controller 51 monitors the temperature of the battery module 49, monitors the state of each battery cell 50, and controls charging and discharging. The battery cell 50 of this embodiment is a lithium ion secondary battery.

The battery control device 45 is communicably connected to the cutoff switch 47 and each module controller 51 . The battery control device 45 transmits and receives various information to and from each module controller 51 and controls the cutoff switch 47 . The battery control device 45 acquires the state of charge (SOC) of the battery 46 through communication with each module controller 51 . Also, the battery control device 45 can communicate with the controller 42 and transmits and receives various information to and from the controller 42 . Battery device 40 outputs supply power Wout1 from terminals 53 and 54 when driving motor 23 for traveling. Also, when the running motor 23 is regeneratively operated, the charging power Win2 is input to the terminals 53 and 54 . Supply power Wout1 and charging power are DC power.

The inverter device 41 has an inverter control device 55 and an inverter 56 . The inverter 56 has an inverter circuit 57 . The inverter circuit 57 is communicably connected to the inverter control device 55 . When driving the traveling motor 23 , the inverter circuit 57 is controlled based on a control signal from the inverter control device 55 . Power supply Wout1 input from battery device 40 is converted into drive power Wout2 (AC power) and output to motor 23 for running.
The inverter circuit 57 is controlled based on a control signal from the inverter control device 55 when the running motor 23 is regeneratively operated. Regenerative electric power Win1 (AC power) input from running motor 23 is converted into charging power Win2 (DC power) by inverter circuit 57 and output to battery device 40 .

The inverter control device 55 is communicably connected to the controller 42 and transmits/receives various information to/from the controller 42 . When the inverter control device 55 receives drive information including a target rotation speed and an instruction to drive the drive motor 23 (for example, the direction of rotation of the drive motor 23) from the controller 42, the inverter control device 55 controls the inverter based on the received drive information. Controls circuit 57;

The inverter control device 55 is connected to a motor rotation detector 58 that detects the rotation direction and number of rotations of the traveling motor 23 . When the inverter control device 55 receives an instruction for regenerative operation of the traveling motor 23 (for example, the direction of rotation of the traveling motor 23) and regeneration information including regenerative force from the controller 42, based on the received regeneration information, It controls the inverter circuit 57 . A detection signal from the motor rotation detector 58 is input to the inverter control device 55, and the rotation direction and the number of rotations of the rotation shaft of the traveling motor 23 can be detected.

Traveling motor 23 is rotationally driven forward or backward by driving electric power Wout2 from inverter device 41 when it is driven. Further, when regeneratively operated, the traveling motor 23 is rotationally driven from the drive wheels 24 via the speed reduction mechanism to generate regenerative electric power Win1.

The controller 42 corresponds to a control device and is communicably connected to the battery control device 45 . Various information is transmitted and received between the controller 42 and the battery control device 45 . For example, the controller 42 transmits transmission request information requesting transmission of battery information to the battery control device 45, and from the battery control device 45, the battery temperature, the battery voltage, the battery charging rate, and the battery state (whether there is an abnormality in the battery, etc.) receive battery information including

Also, the controller 42 is communicably connected to the inverter control device 55 . Various information is transmitted and received between the controller 42 and the inverter control device 55 . For example, the controller 42 transmits transmission request information requesting transmission of inverter information to the inverter control device 55 and receives inverter information including the rotation speed and rotation direction of the traveling motor 23 from the inverter control device 55 . Further, when driving the traveling motor 23 , the controller 42 transmits driving information including the driving operation, the number of revolutions, and the direction of rotation to the inverter control device 55 . Further, when causing the traveling motor 23 to regenerate, the controller 42 transmits regeneration information including regenerative operation and regenerative power to the inverter control device 55 .

As shown in FIG. 3, the controller 42 is communicably connected to an accelerator sensor 43 corresponding to accelerator operating state detection means. The accelerator sensor 43 detects the tilt direction of the accelerator lever 29 to the front and rear and the tilt angle from the neutral state (accelerator opening (operation amount)). The accelerator sensor 43 of this embodiment is an accelerator sensor using a potentiometer. A detection signal from the accelerator sensor 43 is transmitted to the controller 42, and the controller 42 can detect the tilt direction of the accelerator lever 29 and the tilt angle from the neutral state (accelerator opening (operation amount)).

When the operator operates the accelerator lever 29 in the stopped forklift 10 to tilt it forward from the neutral state, the forklift 10 starts moving forward and reaches a speed corresponding to the forward tilt angle of the accelerator lever 29. accelerate to reach Further, when the operator operates the accelerator lever 29 in the stopped forklift 10 to tilt it backward from the neutral state, the forklift 10 starts to move backward, and responds to the backward tilt angle of the accelerator lever 29. Accelerate to reach speed.

As shown in FIG. 3, controller 42 is communicatively connected to monitor 34 . The monitor 34 displays various information based on display information from the controller 42 .

Next, a procedure for controlling the traveling motor 23 by the controller 42 will be described with reference to the flowchart of FIG. First, the controller 42 acquires inverter information from the inverter control device 55 (see step S01). The inverter information is information including the rotation speed and rotation direction of the traveling motor 23 .

Next, the controller 42 acquires the operating direction and operating amount of the accelerator lever 29 (see step S02). The operating direction and operating amount of the accelerator lever 29 are acquired based on the detection signal input from the accelerator sensor 43 . The accelerator sensor 43 detects the operation direction of the accelerator lever 29 (either the forward direction, the reverse direction, or the neutral position) and the tilt angle (forward tilt angle or rearward tilt angle) of the accelerator lever 29 from the neutral state. That is, the accelerator sensor 43 detects the operation direction of the accelerator lever 29 and the operation amount corresponding to the accelerator opening of the accelerator lever 29 . The controller 42 acquires and stores the provisional rotation direction of the traveling motor 23, the provisional target rotation speed, and the provisional target torque corresponding to the provisional target rotation speed based on the operation direction and the operation amount of the accelerator lever 29. A provisional target regenerative force is obtained, and the obtained provisional target regenerative force is stored (see step S03).

Next, the controller 42 transmits transmission request information to the battery control device 45, and receives battery information including battery voltage, battery temperature, battery state, etc. from the battery control device 45 (see step S04).

Next, the controller 42 reads the charging rate (battery charging rate) of the battery 46 included in the battery information, and determines whether the battery charging rate is equal to or less than the threshold (see step S05). In this embodiment, when the fully charged state of the battery is 100%, the thresholds are, for example, a battery charging rate of 80% (first threshold) and a battery charging rate of 50% (second threshold). The controller 42 changes the limit start temperature T11 (° C.) when the battery charging rate below the first threshold is less than 80%, and when the battery charging rate below the second threshold is 50% or below, the limit is changed. Change the starting temperature T11 (see step S06). The restriction start temperature T11 is, for example, 50.degree. C. to 53.degree.

Here, the "battery/upper limit rotation speed information" indicating the restriction start temperature T11 will be described with reference to FIG. The “battery temperature/upper limit rotation speed information” is information indicating the relationship between the battery temperature and the upper limit rotation speed of the drive motor 23, and is stored in the controller 42 in advance. Battery temperatures T12, T13, T14, T15, and T2 (° C.) are set as the battery temperature, each of which rises from the limit start temperature T11 by a predetermined temperature (for example, by 1° C. to 4° C.). The usable upper limit temperature T2 of the battery temperature is set to a temperature slightly lower than the specified temperature T3 at which the warning/input/output cutoff of the battery 46 is performed. For example, when the specified temperature T3 of the battery 46 is 60.degree. C., the usable upper limit temperature T2 is set to 55.degree.

When the battery temperature is lower than the limit start temperature T11, the upper limit rotation speed of the traction motor 23 may be set to the upper limit rotation speed N1 (rpm), which is the normal upper limit rotation speed, or may be set to the upper limit rotation speed N1 (rpm). You can leave it blank. On the other hand, when the battery temperature is in the first high-temperature state equal to or higher than the restriction start temperature T11, the upper limit rotation speed of the driving motor 23 is set to the upper limit rotation speed that decreases step by step each time the battery temperature rises. and limited. Specifically, each time the battery temperatures rise to T12, T13, T14, T15, and T2, the upper limit rotation speeds N2 and N3 are sequentially lowered in steps of about 10% to 15% from the normal upper limit rotation speed N1. , N4, N5, N6, N7 (rpm) and limited. The upper limit rotation speeds N1 to N7 correspond to the upper limit values of the output of the drive motor that are limited according to the temperature of the battery 46. FIG.

For example, when the battery temperature rises to the usable upper limit temperature T2, the upper limit rotation speed of the traction motor 23 is lowered to about 30% to 40% of the normal upper limit rotation speed N1 (lowest upper limit rotation speed N7). upper limit) and limited. Then, when the battery temperature rises to the second high-temperature state equal to or higher than the usable upper limit temperature T2, the upper limit rotation speed of the driving motor 23 is set to the lowest upper limit rotation speed N7 (minimum upper limit value) and is limited. be. Note that the restriction start temperature T11 is set as a temperature lower than the specified temperature T3. A usable upper limit temperature T2 is set between the specified temperature T3 and the restriction start temperature T11, and T12 to T15 are set between the restriction start temperature T11 and the usable upper limit temperature T2. The specified temperature T3, the maximum usable temperature T2, the restriction start temperature T11, and the maximum rotational speed information shown in FIG. In addition, as will be described later, the battery control device 45 uses the cutoff switch 47 to cut off power input/output to the battery 46 when the battery temperature reaches or exceeds the specified temperature T3.

That is, until the battery temperature rises from the usable upper limit temperature T2 to the specified temperature T3 and the input/output of electric power by the battery device 40 is interrupted, the upper limit rotation speed of the driving motor 23 is kept at the lowest upper limit rotation speed N7 (minimum upper limit). Therefore, the controller 42 can drive the driving motor 23 at the lowest upper limit rotation speed N7 (lowest upper limit) until the battery temperature rises from the usable upper limit temperature T2 to the specified temperature T3.

Returning to FIG. 4, when it is determined in step S05 that the battery charging rate is equal to or higher than the first threshold of 80%, the controller 42 does not change the restriction start temperature T11. Incidentally, in the case of a lithium ion secondary battery, the limit start temperature T11 is, for example, 53° C. when the battery charging rate is 80% or higher. When the battery charging rate becomes equal to or higher than the second threshold of 50% and less than the first threshold of 80% and the restriction start temperature T11 is changed in step S05, the restriction start temperature T11 is changed from 53° C. to 2° C., for example. Change to low 51°C.

In this embodiment, the usable upper limit temperature T2 is changed as well as the restriction start temperature T11 is changed according to the battery charging rate. For example, if the specified temperature T3 of the battery 46 is 60° C., the usable upper limit temperature T2 before the change is set to, for example, 58° C. is changed, for example, from 58°C to 56°C, which is 2°C lower. The reduced temperature is set within a range in which the temperature of the battery 46 does not exceed the specified temperature T3 due to rapid charging even if the battery 46 whose temperature has risen to the usable upper limit temperature T2 is rapidly charged. Further, the battery temperatures T12 to T15 at which the upper limit rotation speed is limited are changed according to the battery charging rate, like the limit start temperature T11 and the usable upper limit temperature T2.

When the battery charging rate is less than the second threshold of 50% and the restriction start temperature T11 is changed in step S05, the restriction start temperature T11 is changed from 53°C to 50°C, which is 3°C lower, for example. Further, in the present embodiment, the usable upper limit temperature T2 is changed together with the change of the restriction start temperature T11. For example, when the specified temperature T3 of the battery 46 is 60° C., when the battery charging rate becomes less than 50%, the limit start temperature T11 is changed and the usable upper limit temperature T2 is lowered, for example, from 58° C. by 3° C. Changed to 55°C. The battery temperatures T12 to T15 at which the upper limit rotation speed is limited are changed according to the battery charging rate, like the limit start temperature T11 and the usable upper limit temperature T2.

Next, the controller 42 reads out the battery temperature included in the battery information, and determines whether or not the battery temperature has risen to or above the limit start temperature T11 at which the upper limit rotational speed of the drive motor 23 is started to be limited. is determined (see step S07). A temperature equal to or higher than the restriction start temperature T11 corresponds to the first high temperature state.

When the controller 42 determines that the battery temperature has risen to the limit start temperature T11 or higher, the upper limit rotation speed is calculated based on the battery temperature (see step S08 ). When it is determined that the battery temperature is lower than the limit start temperature T11, the high temperature warning is canceled and the stop warning is canceled (see step S09 ).

The controller 42 obtains and stores the upper limit rotation speed of the driving motor 23 corresponding to the battery temperature based on the "battery temperature/upper limit rotation speed information" shown in FIG. 5 (see step S07). After the upper limit rotation speed is calculated based on the battery temperature in step S08, the controller 42 determines whether the provisional target rotation speed obtained in step S03 is greater than the upper limit rotation speed calculated in step S07. Determine (see step S10).

When it is determined in step S10 that the provisional target rotation speed is equal to or lower than the upper limit rotation speed of the traveling motor 23, the controller 42 proceeds to step S12, which will be described later. On the other hand, when it is determined in step S10 that the provisional target rotation speed is greater than the upper limit rotation speed of the driving motor 23, the controller 42 temporarily sets the upper limit rotation speed of the driving motor 23 calculated based on the battery temperature. It is stored as the target rotation speed (see step S11). At this time, the controller 42 stores the upper limit rotation speed lowered in stages based on the battery temperature as a provisional target rotation speed, and also stores the driving motor 23 corresponding to the upper limit rotation speed lowered in steps based on the battery temperature. is obtained and stored as a provisional target torque.

Next, the controller 42 reads out the battery temperature acquired in step S04, and determines whether or not this battery temperature is equal to or higher than the usable upper limit temperature T2 (see step S12). Then, when the controller 42 determines that the battery temperature is higher than the restriction start temperature T11 and is in the first high temperature state lower than the usable upper limit temperature T2, the controller 42 issues a high temperature warning ( See step S13). In this case, the controller 42 displays a "high temperature warning" on the monitor 34 to notify the operator that the battery temperature of the battery 46 has reached the limit start temperature T11 or higher. The warning displayed on the monitor 34 is, for example, "Battery temperature is rising."

When the controller 42 determines that the battery temperature is in the second high temperature state equal to or higher than the usable upper limit temperature T2, the controller 42 issues a stop warning (see step S14). The controller 42 displays a "stop warning" on the monitor 34 to the effect that the battery temperature of the battery 46 is higher than the usable upper limit temperature T2, and if this continues, the input/output of the battery device 40 will be cut off and stopped. and notify the operator. The "notification" by the high temperature warning and stop warning is not limited to the display on the monitor 34, and may be notified by a buzzer, lamp, or the like.

Subsequently, the controller 42 stores the rotation direction stored in the provisional rotation direction as the final rotation direction, stores the rotation speed stored in the provisional target rotation speed as the final target rotation speed, and stores it in the provisional target torque. The current torque is stored as the final target torque, and the regenerative force stored in the provisional target regenerative force is stored as the final target regenerative force (see step S15).

Next, the controller 42 transmits motor control information including the final rotation direction, final target rotation speed, final target torque, and final target regenerative force to the inverter control device 55 (see step S16). The final rotation direction, final target rotation speed, final target torque, and final target regenerative force are information stored in the controller 42 in step S15. The inverter control device 55 controls the traveling motor 23 based on the motor control information.

Next, the controller 42 determines whether cutoff message information has been input from the battery control device 45 to the effect that the input/output will be cut off after X seconds, that is, that the power supply of the battery device 40 will be cut off after X seconds. Determine (see step S17). When the controller 42 determines that the cutoff message information has been input from the battery control device 45, the monitor 34 displays a "shutoff warning" indicating that the input/output of the battery device 40 will be cut off and stopped after X seconds. (see step S18). The "blocking warning" displayed on the monitor 34 is, for example, "Stop in X seconds.". On the other hand, when the controller 42 determines that the shutdown message information has not been input from the battery control device 45, it cancels the shutdown warning (see step S19). When the “blocking warning” is displayed on the monitor 34 , the controller 42 cancels (erasing) the display of the “blocking warning” on the monitor 34 . After going through a series of steps S01 to S19, the processing of the flow shown in FIG. 4 ends.

Next, operation of the forklift 10 according to this embodiment will be described. The operator accelerates or brakes the forklift 10 by operating the accelerator lever 29 .

During acceleration of the forklift 10, the DC power of the battery 46 is converted into AC power by the inverter 56, and the rotation speed of the traveling motor 23 is increased by the AC power. When the battery charging rate is equal to or higher than the first threshold of 80%, the battery temperature is higher than the limit start temperature T11 and lower than the usable upper limit temperature T2 due to discharging of the battery 46, etc., and is in the first high temperature state. , the traveling motor 23 is subject to the upper limit rotation speed. Therefore, the operator feels that the intended acceleration cannot be obtained, and along with the display of the high temperature warning displayed on the monitor 34, recognizes that the temperature of the battery 46 (battery temperature) is rising. Further, when the battery temperature is lower than the specified temperature T3 and higher than the usable upper limit temperature T2, which is the second high temperature state, the driving motor 23 is subject to the maximum upper limit rotation speed. Therefore, the operator strongly feels that the intended acceleration cannot be obtained, and along with the display of the stop warning displayed on the monitor 34, recognizes that the temperature of the battery 46 has risen to near the specified temperature T3.

When the forklift 10 is braked, a regenerative force is generated by the regenerative operation of the traveling motor 23 . The regenerative power Win1 generated in the running motor 23 is converted by the inverter 56 into charging power Win2 of DC power, and the battery 46 is charged (see FIG. 3). When the battery temperature is in the first high-temperature state, in which the battery temperature is higher than the restriction start temperature T11 and lower than the usable upper limit temperature T2, the traveling motor 23 is restricted to the upper limit rotation speed. The charging power obtained by regeneration under the condition that the upper limit rotation speed is restricted is the electric power obtained from the regenerative force corresponding to the restricted upper limit rotation speed, and the regenerative force corresponding to the unrestricted rotation speed. less than the charging power available from In other words, the regenerative force generated by the regenerative operation of the driving motor 23 is limited as the rotational speed of the driving motor 23 is limited according to the temperature of the battery 46 . Therefore, the battery temperature does not rise to the specified temperature T3 due to regenerative charging corresponding to the restricted upper limit rotation speed. Further, when the battery temperature is lower than the specified temperature T3 and higher than the usable upper limit temperature T2, which is the second high temperature state, the driving motor 23 is subject to the maximum upper limit rotation speed. Therefore, the charging power obtained from the regenerative power corresponding to the restricted upper limit rotation speed is less than the charging power obtained from the regenerative power corresponding to the unlimited rotation speed. Therefore, the battery temperature does not rise to the specified temperature T3 due to regenerative charging corresponding to the upper limit rotation speed of the maximum limit.

On the other hand, when the battery charging rate is equal to or higher than the second threshold of 50% and lower than the first threshold of 80%, the restriction start temperature T11 and the usable upper limit temperature T2 are lower than when the battery charging rate is 80% or higher. set. When the battery charging rate is less than 50%, which is the second threshold, the restriction start temperature T11 and the usable upper limit temperature T2 are set lower than when the battery charging rate is 50% or more and less than 80%. In addition, each battery temperature T12, T13, T14, T15, and T2, which rises by a predetermined temperature (for example, by 1° C. to 4° C.) from the limit start temperature T11, is also the threshold of the battery charging rate (first threshold, second threshold). is set lower depending on Limitation of the number of rotations of the traveling motor 23 is started at a temperature lower than when the battery charging rate is 80% or higher. Therefore, even if the operation of the forklift 10 is interrupted after the number of rotations of the traveling motor 23 is limited, and the battery 46 is immediately charged quickly while the temperature of the battery 46 does not drop, the battery 46 will not reach the specified temperature. Does not rise to T3.

Next, a case where a switchback operation for tilting the accelerator lever 29 tilted forward (backward) backward (forward) is performed while the forklift 10 is traveling forward (backward) will be described. When the switchback operation is performed, the forklift 10 obtains greater braking than the accelerator off braking by the operation of returning the accelerator lever 29 in a forward tilting (rearward tilting) state to the neutral position. Therefore, when the switchback operation is performed, a large regenerative force is generated by the regenerative operation of the traveling motor 23, and the forklift 10 stops in a shorter distance than the accelerator-off braking. The regenerative power Win1 generated in the traveling motor 23 is converted by the inverter 56 into charging power Win2 of DC power, and the battery 46 is charged.

In this embodiment, even when the switchback operation is performed, the temperature of the battery 46 limits the output of the drive motor 23 and the regenerative power of the regenerative operation. Here, a switchback operation in which the accelerator lever 29, which is tilted forward, is tilted backward to switch from forward to reverse will be described.

As shown in FIG. 6, when the battery charging rate is equal to or higher than the first threshold value of 80% and the battery temperature is equal to or lower than the limit start temperature T11, the driving motor 23 is limited to the upper limit rotation speed and the regenerative force is limited. not. Therefore, in forward running before the switchback operation, the acceleration as intended by the operator is obtained, and after the switchback operation, the braking force as intended by the operator is obtained.

When the battery charging rate is equal to or higher than the first threshold of 80%, the battery temperature is higher than the limit start temperature T11 and lower than the usable upper limit temperature T2 due to discharging of the battery 46, etc., and is in the first high temperature state. , the running motor 23 is subject to restrictions on the upper limit rotation speed and the regenerative force. For this reason, in forward running before the switchback operation, the operator feels that the intended acceleration cannot be obtained, and a high temperature warning is displayed on the monitor 34, and the temperature of the battery 46 (battery temperature) rises. recognize that there are Also, after the switchback operation, the operator feels that the intended braking force cannot be obtained.

The charging power obtained by the switchback operation is the power obtained from the regenerative power corresponding to the limited upper limit rotational speed of the driving motor 23 before the switchback operation, and the regenerative power corresponding to the unrestricted rotational speed. less than the charging power available from the power. That is, the regenerative force of the regenerative operation of the drive motor 23 after the switchback operation is limited according to the limit of the rotation speed of the drive motor 23 according to the temperature of the battery 46 before the switchback operation. Therefore, as shown in FIG. 6, in the switchback operation in which the upper limit rotation speed and the regenerative force of the traveling motor 23 are limited, the running speed is the same as in the case of the switchback operation in which the upper limit rotation speed and the regenerative force are not limited. A balance is maintained between the output of the motor 23 and regeneration. Therefore, in a switchback operation subject to restrictions on the upper limit rotation speed and regenerative force of the traveling motor 23, the braking distance of the forklift 10 due to the switchback operation is as follows: The braking distance can be the same as the distance.

Incidentally, assuming that control is performed to limit only the regeneration without limiting the output of the running motor 23 in the first high-temperature state, in this case, the output of the running motor 23 before the switchback operation is not restricted. So the operator can get the desired acceleration. However, after the switchback operation, the operator cannot obtain the intended braking force due to the limitation of regeneration. As shown in FIG. 6, in the switchback operation when the traveling motor 23 is not restricted by the upper limit rotation speed but by the regenerative force, the balance between the output of the traveling motor 23 and regeneration is not maintained. . Therefore, in the switchback operation in which only the regenerative force is limited without the traveling motor 23 being restricted to the upper limit rotation speed, the braking distance of the forklift 10 due to the switchback operation is not limited to the upper limit rotation speed and the regenerative force. The braking distance becomes longer than the braking distance of the switchback operation, and the forklift 10 cannot be stopped at the braking distance intended by the operator.

In this embodiment, although the upper limit rotation speed and regenerative force of the traveling motor 23 are restricted, the output of the traveling motor 23 and the regeneration are balanced. In other words, not only the output of the running motor 23 but also the regeneration is limited, so although the braking force is lower than before the normal limitation, the braking distance can be the same as the braking distance during normal braking. no increase in Therefore, the braking distance of the forklift 10 due to the switchback operation can be the same braking distance as the braking distance of the switchback operation in which the upper limit rotation speed is not limited and the regenerative force is not limited. Therefore, the operator can stop the forklift 10 at the intended braking distance by the switchback operation. In addition, in the switchback operation for switching from reverse to forward by tilting the accelerator lever 29 which is tilted backward, output and regeneration of the traveling motor 23 are generated in the same manner as in the case of the switchback operation for switching from forward to reverse. is maintained in balance with

The forklift 10 of this embodiment has the following effects.
(1) When the temperature of the battery 46 is in the first high temperature state equal to or higher than the restriction start temperature T11, the output of the drive motor 23 is restricted according to the temperature of the battery 46 . For this reason, the forklift 10 is operated while the output of the traveling motor 23 is restricted. As a result, the operator can feel the limitation of the output of the traveling motor 23 from the operation of the forklift 10, and can recognize that the battery 46 is about to be cut off. Further, by limiting the output of the traveling motor 23 before the battery 46 is cut off, the operator can interrupt the work, and the frequency of occurrence of the battery 46 cut off can be reduced.

(2) The output of the drive motor 23 limited by the controller 42 is the number of rotations of the drive motor 23. When the temperature of the battery 46 is in the first high temperature state equal to or higher than the limit start temperature T11, the temperature of the battery 46 is Accordingly, the rotation speed of the traveling motor 23 is limited. Since the number of rotations of the running motor 23 is limited, the running speed decreases or the acceleration slows down depending on the temperature of the battery 46 . As a result, the operator can feel a decrease in traveling speed and slow acceleration, and can recognize that the battery 46 is about to be cut off.

(3) When the temperature of the battery 46 detected by the battery temperature detector 52 is in the first high temperature state equal to or higher than the restriction start temperature T11, the controller 42 increases the rotation speed of the driving motor 23 according to the temperature of the battery 46. Limited. Regenerative force generated by the regenerative operation of the traveling motor 23 is limited as the number of rotations of the traveling motor 23 is limited according to the temperature of the battery 46 . Therefore, when the temperature of the battery 46 is in the first high temperature state equal to or higher than the restriction start temperature T11, the regenerative power of the traction motor 23 is restricted according to the temperature of the battery 46 .

(4) When the temperature of the battery 46 is in the first high temperature state, the upper limit value of the output of the drive motor 23 to be limited according to the temperature of the battery 46 is increased as the temperature of the battery 46 rises from the limitation start temperature T11. It is set to decrease in stages. Therefore, the operation of the running motor 23 can be gradually reduced. The operator can feel that the operation of the traveling motor 23 is gradually lowered, and can recognize that the battery 46 is about to be cut off.

(5) When the temperature of the battery 46 is in the second high temperature state from the usable upper limit temperature T2 higher than the restriction start temperature T11 to the specified temperature T3, the temperature of the running motor 23 is restricted according to the temperature of the battery 46. The driving motor 23 is driven by setting the upper limit value of the output to the lowest upper limit value. Therefore, in the second high temperature state, the operation of the traveling motor 23 of the forklift 10 is restricted to the maximum. As a result, the operator can feel that the operation of the traveling motor 23 is maximally restricted, and can recognize that the battery 46 is about to be cut off.

(6) When the battery charging rate is 50% or more and less than 80% and when the battery charging rate is less than 50%, the restriction start temperature T11 and the usable upper limit temperature T2 are set to the battery charging rate of 80% or more. is set lower than Restriction of the number of rotations of the traveling motor 23 and restriction of regenerative power are started from a temperature lower than that when the battery charging rate is 80% or more. Therefore, even if the operation of the forklift truck 10 is interrupted and the battery 46 is quickly charged immediately after the rotation speed of the traveling motor 23 is restricted or the regenerative force is restricted, the battery 46 does not rise to the specified temperature T3. . In other words, the battery 46 will not be cut off due to rapid charging after work is interrupted.

(7) Although the driving motor 23 is restricted by the upper limit rotation speed and the regenerative force in the switchback operation, the balance between the output of the driving motor 23 and regeneration is maintained. Therefore, the braking distance of the forklift 10 due to the switchback operation can be the same braking distance as the braking distance of the switchback operation in which the upper limit rotation speed is not limited and the regenerative force is not limited. In other words, although the regeneration of the running motor 23 is restricted, the braking force is reduced compared to before the restriction. Also, the impact caused by sudden braking can be mitigated. The operator can stop the forklift 10 at an intended braking distance by the switchback operation, similar to the switchback operation in which the upper limit number of rotations is limited and the regenerative force is not limited. Further, the operator can operate the accelerator lever 29 with the same feeling as braking in a normal switchback operation even when the traveling motor 23 is restricted by the upper limit rotation speed and the regenerative force.

The present invention is not limited to the above embodiments, and various modifications are possible within the scope of the invention. For example, the following modifications may be made.

O In the above-described embodiment, control of the driving motor is exemplified as the driving motor, but the driving motor is not limited to the driving motor. The drive motor may be a cargo handling motor. When the drive motor is a motor for cargo handling, the output of the motor for cargo handling required for cargo handling operation is limited by the rise in battery temperature, and the operator can recognize that the battery is about to be cut off.
○ In the above embodiment, when the battery charging rate is less than 80% (50% or more), the restriction start temperature that defines the first high temperature state is lowered, and when the battery charging rate is less than 50%, the restriction start temperature I tried to make it even lower, but it's not limited to this. Also, the control device may change the limit start temperature in consideration of the temperature rise due to charging according to the battery charging rate. Also, the threshold of the battery charging rate may be set according to the characteristics of each battery with different conditions, and is not limited to the threshold described in the above embodiment.
O In the above embodiment, the battery is a lithium ion secondary battery, but the battery is not limited to a lithium ion battery. The battery may be, for example, a secondary battery such as a nickel-metal hydride battery with a battery control device capable of monitoring the state of the battery and controlling the battery.
O In the above embodiment, the control is performed to limit the number of revolutions of the drive motor when the battery temperature rises, but the control is not limited to the control of the number of revolutions of the drive motor. For example, the control device may limit the regenerative force instead of the number of revolutions of the drive motor. In this case, the regenerative force of the drive motor is set in advance when the temperature of the battery is higher than the limit start temperature, higher than the limit start temperature, and lower than the usable upper limit temperature in the first high temperature state. It may be limited to the upper limit regenerative power. Since the regenerative power is limited due to the rise in battery temperature, the operator feels that the intended braking operation will be difficult due to the limitation of the regenerative power. can recognize that Further, when the battery temperature is lower than the specified temperature and higher than the usable upper limit temperature, which is the second high temperature state, the regenerative force of the traction motor may be restricted to the maximum. In this case, the operator strongly feels that it is difficult to perform the intended braking operation due to the limitation of regenerative power, and along with the stop warning displayed on the monitor, he/she recognizes that the battery temperature has risen to near the specified temperature. do. Further, the limit of the regenerative force may be reduced step by step as the temperature of the battery rises, similar to the limit of the number of revolutions. Furthermore, when the charging rate of the battery is less than a preset threshold, the limit start temperature may be lower than when the charging rate of the battery is equal to or higher than the threshold.
O In the above embodiment, the control is performed to limit the number of revolutions of the drive motor when the battery temperature rises, but the control is not limited to the control of the number of revolutions of the drive motor. For example, instead of the number of rotations of the drive motor, the degree of opening of the accelerator lever may be limited. In this case, the opening degree of the accelerator lever is set in advance when the temperature of the battery is higher than the limit start temperature, higher than the limit start temperature, and lower than the usable upper limit temperature in the first high temperature state. It may be limited to the upper limit opening. Since the degree of opening of the accelerator lever is limited by the increase in battery temperature, the operator can recognize that the battery is about to be cut off. For example, even if the accelerator lever is tilted forward 100%, the limit is equivalent to tilting the accelerator lever forward 80%. Further, when the battery temperature is lower than the specified temperature and higher than the usable upper limit temperature, which is the second high temperature state, the opening degree of the accelerator lever may be restricted to the maximum. In this case, the operator strongly feels that it is difficult to perform the intended operation due to the limited opening of the accelerator lever, and a stop warning is displayed on the monitor, along with the fact that the battery temperature has risen to near the specified temperature. to recognize Further, the limit on the degree of opening of the accelerator lever may be reduced in stages as the temperature of the battery rises, similar to the limit on the number of revolutions. Furthermore, when the charging rate of the battery is less than a preset threshold, the limit start temperature may be lower than when the charging rate of the battery is equal to or higher than the threshold .
In the above- described embodiment, an accelerator lever operated by hand is exemplified as the accelerator operating means, but the accelerator operating means is not limited to the accelerator lever. The accelerator operating means may be, for example, an accelerator pedal that is operated by stepping on it.
O In the above embodiment, the reach-type forklift was exemplified as the battery-powered industrial vehicle, but the battery-powered industrial vehicle is not limited to the reach-type forklift. For example, it may be a counterweight type battery forklift or an electric towing vehicle.

10 Forklift (battery-powered industrial vehicle)
11 Vehicle body 14 Cargo handling device 22 Drive unit 23 Driving motor 24 Drive wheel 29 Accelerator lever 40 Battery device 41 Inverter device 42 Controller (control device)
43 Accelerator sensor 45 Battery controller 46 Battery 47 Cutoff switch 48 Battery module unit 49 Battery module 51 Module controller 52 Battery temperature detector 55 Inverter controller 56 Inverter 57 Inverter circuit 58 Motor rotation detector 59 Accelerator sensor T11 Battery temperature (limit start temperature)
T12, T13, T14, T15 Battery temperature T2 Battery temperature (usable upper limit temperature)
T3 Battery temperature (specified temperature)
N1, N2, N3, N4, N5, N6 Upper limit speed N7 Upper limit speed (minimum upper limit)

Claims (6)

a drive motor;
a battery device that outputs electric power when driving the driving motor and receives electric power when the driving motor is regeneratively operated;
battery temperature detection means for detecting the temperature of the battery provided in the battery device;
a control device connected to an accelerator sensor that acquires an operation direction and an operation amount of an accelerator lever, and that controls the drive motor so as to achieve a running speed corresponding to the operation amount of the accelerator lever acquired by the accelerator sensor ; In a battery-powered industrial vehicle equipped with
When the temperature of the battery detected by the battery temperature detection means is equal to or higher than a preset limit start temperature and is lower than the usable upper limit temperature , the controller controls the temperature of the battery according to the temperature of the battery. to limit the output of the drive motor,
An upper limit value of the output of the drive motor to be limited according to the temperature of the battery when the first high-temperature state is established is set so as to decrease stepwise as the temperature of the battery rises from the limitation start temperature. control like
When the temperature of the battery is in the first high temperature state, the upper limit value of the output of the drive motor is such that the boarding operator can feel the decrease in traveling speed and slow acceleration, and the input/output of the battery device is maintained for a predetermined time. A plurality of temperature increases set by increasing the temperature by a predetermined temperature from the limit start temperature so that the impending cutoff state of the battery can be recognized before the cutoff warning to the effect that the battery will be cut off and stopped later is generated. A battery-powered industrial vehicle characterized in that the temperature of the battery decreases sequentially in multiple steps at a predetermined rate corresponding to the temperature of the battery. 2. The battery-powered industrial vehicle according to claim 1, wherein the output of said drive motor limited by said control device is the number of revolutions of said drive motor or the torque of said drive motor. When the temperature of the battery detected by the battery temperature detection means is in a first high-temperature state equal to or higher than the limit start temperature, the control device controls the regenerative power generated by the regenerative operation of the drive motor in accordance with the temperature of the battery. 2. The battery powered industrial vehicle of claim 1, wherein limiting. When the temperature detected by the battery temperature detecting means is equal to or higher than a predetermined temperature higher than the restriction start temperature, the battery device outputs electric power from the battery device to the battery device. cut off the power input of
The control device is preset with a usable upper limit temperature that is higher than the restriction start temperature and lower than the specified temperature,
When the temperature of the battery detected by the battery temperature detection means is in a second high temperature state from the usable upper limit temperature or more to the specified temperature, the control device limits the driving according to the temperature of the battery. 4. The battery-powered industrial vehicle according to any one of claims 1 to 3, wherein control is performed so as to set the upper limit of the output of the motor to the lowest upper limit . The battery-powered industrial vehicle according to any one of claims 1 to 4 , wherein the control device changes the limit start temperature based on the charging rate of the battery. 3. The control device, when the charging rate of the battery is less than a preset threshold, sets the restriction start temperature lower than the restriction start temperature when the charging rate of the battery is equal to or higher than the threshold. 6. The battery-powered industrial vehicle according to any one of 1-5.

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