Work vehicle and method for controlling work vehicle

Abstract

This work vehicle travels through a work site with electric power supplied from a battery. A cooling device of the present invention cools the battery. A control device of the present invention controls the cooling device according to the gradient of the work site through which the work vehicle travels.

Description

Work vehicle and work vehicle control method

[0001] This application claims priority to Japanese Patent Application No. 2024-056374, filed on March 29, 2024, the contents of which are incorporated herein by reference.

[0002] There are work vehicles equipped with batteries and driven by power supplied from the batteries. It is known that batteries generate heat when they are charged and discharged, and that higher temperatures cause deterioration.

[0003] Patent Document 1 discloses a technology for maintaining transport efficiency while reducing damage to the road surface caused by driving by a transport vehicle, with a function for displaying a recommended driving speed to reduce damage to the vehicle body. Patent Document 2 discloses a technology for limiting the driving speed of an engine-driven transport vehicle even when the accelerator pedal is depressed, with the aim of reducing damage to the vehicle body and improving engine durability.

[0004] Patent No. 6744887 Patent No. 3212234

[0005] Reducing output to prevent a rise in battery temperature, as in Patent Documents 1 and 2, leads to a decrease in work efficiency. An object of the present disclosure is to provide a work vehicle and a control method for a work vehicle that can prevent battery degradation without reducing work efficiency.

[0006] According to one aspect of the present disclosure, a work vehicle has a work implement and travels to a work site using power supplied from a battery, and is equipped with a cooling control unit that controls the cooling performance of the battery in accordance with the gradient of the work site on which the work vehicle travels.

[0007] According to the above aspect, the work vehicle can prevent battery deterioration without reducing work efficiency.

[0008] 1 is a diagram showing the configuration of a transport system including a transport vehicle according to a first embodiment; FIG. 2 is a diagram showing an example of a map according to a first embodiment; FIG. 3 is a perspective view showing a schematic view of a transport vehicle according to a first embodiment; FIG. 4 is a diagram showing the configuration of a battery module according to a first embodiment; FIG. 5 is a schematic block diagram showing the configuration of a control system provided in a transport vehicle according to a first embodiment; FIG. 6 is a diagram showing an example of an estimated rising temperature table according to a first embodiment; FIG. 7 is a diagram showing an example of a method for determining a control command for a BTMS according to a first embodiment; FIG. 8 is a flowchart showing a method for controlling the cooling of a battery of a transport vehicle by a transport system according to a first embodiment; FIG. 9 is a schematic block diagram showing the configuration of a computer according to at least one embodiment;

[0009] First Embodiment <Transportation System 1> Hereinafter, an embodiment will be described in detail with reference to the drawings. FIG. 1 is a diagram showing the configuration of a transportation system 1 including a transportation vehicle 10 according to a first embodiment. The transportation system 1 includes a plurality of transportation vehicles 10 and a management device 50. The transportation system 1 is used to transport cargo such as excavated earth and sand, crushed stone, etc. using the plurality of transportation vehicles 10. The management device 50 collects data from the transportation vehicles 10 and manages the work status of the transportation vehicles 10. The transportation vehicles 10 are an example of work vehicles.

[0010] The work site is provided with an excavation site P1 and an earth unloading site P2. The transport vehicle 10 is loaded with a load by a loading machine 30 at the excavation site P1, transports the load to the earth unloading site P2, and unloads the load at the earth unloading site P2. The loading machine 30 may be, for example, a hydraulic excavator or a wheel loader. After unloading the load at the earth unloading site P2, the transport vehicle 10 moves back to the excavation site P1 and loads the load again. A course C along which the transport vehicle 10 travels is provided at the work site. The course C may be a one-way road as shown in FIG. 1 , or a two-way road.

[0011] <<Management Device 50>> The management device 50 acquires measurement data such as position, direction, traveling speed, and cargo weight from a plurality of haulage vehicles 10, and manages the work status of each haulage vehicle 10. The management device 50 transmits operation data instructing each haulage vehicle 10 on a travel route according to the work status of the haulage vehicle 10. The operation data may be data for instructing an operator on the route to be traveled by the haulage vehicle 10, which is a manned vehicle, or may be data for controlling the travel of the haulage vehicle 10, which is an unmanned vehicle.

[0012] The management device 50 stores a map of the work site. FIG. 2 is a diagram illustrating an example of the map according to the first embodiment. The map according to the first embodiment divides the work site into multiple areas using a mesh, and associates roadway information indicating whether each area is on course C or outside the travel range. Areas related to course C are further associated with gradient information. The gradient information takes one of the following values: large downward gradient, small downward gradient, flat, small upward gradient, or large upward gradient. Note that, since course C in the work site according to the first embodiment is a one-way road, the gradient information associated with the roadway indicates whether it is uphill or downhill. The gradient information in the map according to other embodiments may be associated with a combination of the magnitude and direction of the gradient. In this case, even if the road is a two-way road, it is possible to determine whether the road is an uphill or downhill gradient based on the direction in which the haulage vehicle 10 is facing. Furthermore, although the gradient information in the map according to the first embodiment classifies the magnitude of the gradient as large, small, or flat, this is not limited thereto, and in other embodiments, the gradient information may be expressed as a numerical value such as an inclination angle or a percentage.

[0013] When the management device 50 acquires position measurement data from the haulage vehicle 10, it acquires gradient information at the position where the haulage vehicle 10 is located from the map shown in Figure 2 and notifies the haulage vehicle 10 of the gradient of the current position.

[0014] 3 is a perspective view that schematically shows the transporter vehicle 10 according to the first embodiment. The transporter vehicle 10 includes a dump body 11, a vehicle body 12, and a traveling device 13.

[0015] The dump body 11 is a member on which a load is loaded. At least a portion of the dump body 11 is disposed above the vehicle body 12. The dump body 11 is subjected to dumping and lowering operations by an actuator (not shown). The dumping and lowering operations adjust the dump body 11 to a dumping posture and a loaded posture. The dump posture refers to a posture in which the dump body 11 is raised. The loaded posture refers to a posture in which the dump body 11 is lowered. The actuator may be, for example, an electric actuator such as an electric cylinder or an electric motor, or may be a hydraulic cylinder or hydraulic motor driven by hydraulic oil supplied from a hydraulic pump driven by an electric pump drive motor. The dump body 11 is an example of a work machine.

[0016] The dumping operation refers to an operation of moving the dump body 11 away from the vehicle body 12 and tilting it in the dumping direction. The dumping direction is toward the rear of the vehicle body 12. In the embodiment, the dumping operation includes lifting the front end of the dump body 11 and tilting the dump body 11 rearward. Due to the dumping operation, the loading surface of the dump body 11 tilts downward toward the rear.

[0017] The lowering operation refers to an operation of bringing the dump body 11 closer to the vehicle body 12. In the embodiment, the lowering operation includes lowering the front end of the dump body 11.

[0018] When performing an earth removal operation, the dump body 11 performs a dumping operation to change from a loaded posture to a dump posture. If a load is loaded on the dump body 11, the load is discharged rearward from the rear end of the dump body 11 by the dumping operation. When a loading operation is performed, the dump body 11 is adjusted to the loaded posture.

[0019] The vehicle body 12 includes a vehicle body frame. The vehicle body 12 supports the dump truck body 11. The vehicle body 12 is supported by a traveling device 13.

[0020] The traveling device 13 supports the vehicle body 12. The traveling device 13 causes the transport vehicle 10 to travel. The traveling device 13 causes the transport vehicle 10 to travel forward or backward. At least a portion of the traveling device 13 is disposed below the vehicle body 12. The traveling device 13 has a pair of front wheels and a pair of rear wheels. The front wheels are steered wheels, and the rear wheels are driven wheels. Note that the combination of steered wheels and driven wheels is not limited to this, and the traveling device 13 may be four-wheel drive or four-wheel steering. The traveling device 13 has a traveling drive motor 131. The traveling drive motor 131 is an electric motor for driving the traveling device 13. The traveling drive motor 131 can perform regenerative braking of the traveling device 13 by operating as a generator.

[0021] The vehicle body 12 is provided with a battery module 14 that is a power source for driving the actuator of the dump body 11 and the travel drive motor 131 of the travel device 13. Note that a plurality of battery modules 14 may be provided.

[0022] FIG. 4 is a diagram illustrating the configuration of a battery module 14 according to the first embodiment. The battery module 14 includes a battery 141 and a battery thermal management system (BTMS) 142. The battery 141 generates heat during charging and discharging, and its charge / discharge efficiency varies depending on the operating temperature range. Therefore, temperature regulation is necessary. The BTMS 142 is a system for controlling the temperature of the battery 141. Note that in the battery module 14 according to the first embodiment, the battery 141 and the BTMS 142 are provided in a one-to-one correspondence. However, this is not limited to this. In other embodiments, the number of batteries 141 and the number of BTMSs 142 may differ. For example, one BTMS 142 may control the temperatures of multiple batteries 141. Furthermore, for example, when multiple battery modules 14 are provided, the BTMS 142 of one battery module 14 may control the temperatures of the batteries 141 provided in another battery module 14.

[0023] The battery 141 includes a battery main body 1411, a cooling pipe 1412, and a battery monitoring device 1413. The battery main body 1411 may be, for example, a lithium-ion battery or a nickel-metal hydride battery. The cooling pipe 1412 is a pipe that passes through the housing of the battery 141 and circulates circulating water supplied from the BTMS 142. Heat is exchanged between the battery main body 1411 and the circulating water as the circulating water flows through the cooling pipe 1412. A structure that promotes heat exchange, such as a heat sink, may be provided between the battery 141 and the cooling pipe 1412.

[0024] The battery monitoring device 1413 monitors the state of the battery 141. Specifically, the battery monitoring device 1413 acquires the temperature, charging rate, voltage, etc. of the battery 141 from sensors provided in the battery 141.

[0025] The BTMS 142 includes an intermediate heat exchanger 1421 , a radiator 1422 , a first flow path 1423 , a second flow path 1424 , a first pump 1425 , a second pump 1426 , a fan 1427 , and a BTMS control device 1428 .

[0026] The intermediate heat exchanger 1421 has flow paths on the primary side and the secondary side, and exchanges heat between the coolant flowing on the primary side and the circulating water flowing on the secondary side. In this embodiment, the side where the cooling source, i.e., the radiator 1422, is located is called the primary side, and the side where the cooling target, i.e., the battery main body 1411, is located is called the secondary side. The radiator 1422 passes the coolant and releases heat contained in the coolant to the outside air. The first flow path 1423 connects the cooling pipe 1412 of the battery 141 to the flow path on the secondary side of the intermediate heat exchanger 1421 so as to circulate the coolant. A circulating water sensor 1429 that measures the temperature and flow rate of the circulating water is provided in the first flow path 1423. The circulating water sensor 1429 is provided on each of the upstream and downstream sides of the cooling pipe 1412. The second flow path 1424 connects the flow path on the primary side of the intermediate heat exchanger 1421 to the radiator 1422 so as to circulate the coolant. The second flow path 1424 passes the coolant. The first pump 1425 is provided in the first flow path 1423 and pumps the circulating water. The second pump 1426 is provided in the second flow path 1424 and pumps the cooling water. The fan 1427 sends air to the radiator 1422 to promote heat exchange in the radiator 1422. The BTMS control device 1428 receives control commands and controls the first pump 1425, the second pump 1426, and the fan 1427 in accordance with the control commands. The BTMS control device 1428 outputs measurement data of the temperature and flow rate of the circulating water measured by the circulating water sensor 1429.

[0027] Heat from the battery 141 is transferred via the cooling pipe 1412 to the circulating water flowing in the first flow path 1423. The heat of the circulating water flowing in the first flow path 1423 is transferred via the intermediate heat exchanger 1421 to the cooling water flowing in the second flow path 1424. The heat of the cooling water flowing in the second flow path 1424 is released into the atmosphere via the radiator 1422.

[0028] The transporter vehicle 10 includes a control system 16 that controls the battery 141, the travel drive motor 131, and the actuator of the dump body 11. Fig. 5 is a schematic block diagram showing the configuration of the control system 16 included in the transporter vehicle 10 according to the first embodiment. The control system 16 includes a measuring device 161, a communication device 162, a control device 163, an operation device 164, and a monitor 165.

[0029] The measuring device 161 measures the state of the transport vehicle 10 using various sensors and generates measurement data. Specifically, the measuring device 161 includes a positioning sensor (positioning device) that measures the position and direction of the transport vehicle 10 based on signals from a Global Navigation Satellite System (GNSS), a speed sensor that measures the traveling speed of the transport vehicle 10, and a payload meter that measures the weight of the load on the transport vehicle 10.

[0030] The communication device 162 communicates with the management device 50 via a mobile communication network or the like. The communication device 162 transmits measurement data measured by the measuring device 161 to the management device 50. The communication device 162 receives operation data related to the operation of the haulage vehicle 10 from the management device 50. The operation data may be data for instructing an operator on the route to be traveled by the haulage vehicle 10, which is a manned vehicle, or may be data for controlling the travel of the haulage vehicle 10, which is an unmanned vehicle. The operation data includes at least the gradient at the position where the haulage vehicle 10 is located.

[0031] The control device 163 drives the haulage vehicle 10 in accordance with the control data received by the communication device 162 from the management device 50 and the amount of operation of the operation device 164. The operation device 164 is provided in the driver's cab and accepts operations by the operator. The operation device 164 includes an accelerator pedal, a brake pedal, a steering wheel, a dump lever, etc. A monitor 165 is provided in the driver's cab and displays the driving route, etc. to the operator.

[0032] The control device 163 includes a data acquisition unit 171 , a gradient determination unit 172 , a heat generation amount prediction unit 173 , a cooling amount determination unit 174 , and a cooling control unit 175 .

[0033] The data acquisition unit 171 acquires measurement data from various sensors. Specifically, the data acquisition unit 171 acquires measurement data on the position, direction, traveling speed, and cargo weight of the transport vehicle 10 from the measuring device 161. The data acquisition unit 171 acquires measurement data such as the temperature of the battery 141 from the battery monitoring device 1413. The data acquisition unit 171 acquires measurement data on the temperature and flow rate of the circulating water from the BTMS control device 1428.

[0034] The gradient identification unit 172 identifies the gradient of the current position based on the measurement data of the current position and orientation of the haulage vehicle 10 acquired by the data acquisition unit 171. Specifically, the gradient identification unit 172 transmits the measurement data of the current position to the management device 50 and receives information on the gradient at the current position from the management device 50, thereby identifying the gradient.

[0035] The heat generation amount prediction unit 173 predicts the amount of temperature rise of the battery 141 due to charging and discharging of the battery 141, based on the gradient identified by the gradient identification unit 172. The amount of temperature rise of the battery 141 is the temperature difference between the temperature of the battery 141 predicted based on the gradient identified by the gradient identification unit 172 and the coolant temperature. In other words, the heat generation amount prediction unit 173 predicts the amount of temperature rise of the battery 141 when the power required for powering the haulage vehicle 10 is discharged from the battery 141, based on the gradient identified by the gradient identification unit 172. The heat generation amount prediction unit 173 predicts the amount of temperature rise of the battery 141 when regenerative power generated by braking the haulage vehicle 10 is charged to the battery 141, based on the gradient identified by the gradient identification unit 172. The heat generation amount prediction unit 173 has in advance an estimated temperature rise table for calculating the amount of temperature rise of the battery 141 from the traveling speed, cargo weight, and gradient, and calculates the amount of temperature rise from the measurement data acquired by the data acquisition unit 171. In addition, if the transport vehicle 10 always travels at the speed limit set for course C, the estimated temperature rise table may not have a variable for the travel speed.

[0036] 6 is a diagram showing an example of an estimated temperature rise table according to the first embodiment. The estimated temperature rise table shows the relationship between gradient and temperature rise amount. Specifically, the estimated temperature rise table associates the temperature rise amount with each of a large uphill gradient, a small uphill gradient, flat, a small downhill gradient, and a large downhill gradient. An estimated temperature rise table is prepared for each combination of the weight and traveling speed of the haulage vehicle 10. For example, the heat generation amount prediction unit 173 may have four patterns of estimated temperature rise tables related to the combination of the presence or absence of a load (the weight of the haulage vehicle 10) and the high or low traveling speed.

[0037] Here, the estimated temperature rise table will be described. １ can be calculated by the following formula (1): ２ can be calculated by the following equation (2): where M is the weight of the transport vehicle 10, v is the traveling speed of the transport vehicle 10, θ is the gradient, and C ｒ is the rolling resistance coefficient, C ａ indicates the air resistance coefficient.

[0038]

[0039] The discharge or charge power of the battery 141 can be calculated from the drive efficiency and energy E by calculating in advance the power conversion efficiency of the travel device, the charge / discharge efficiency of the battery, the input / output efficiency of the electrical circuit between the travel device and the battery, and other factors. The relationship between the discharge or charge power of the battery 141 and the temperature rise of the battery 141 can be calculated based on design values ​​appropriate for the type of battery 141. For example, the temperature rise of the battery 141 can be calculated from the discharge or charge power of the battery 141, the charge / discharge efficiency of the battery 141, and the thermal resistance between the circulating water and the battery 141. The thermal resistance between the circulating water and the battery 141 is the sum of the thermal resistance from the cooling pipe 1412 to the contact surface of the battery 141, the thermal resistance at the contact surface of the battery 141, and the thermal resistance from the contact surface of the battery 141 to the center of the battery 141. Therefore, an estimated temperature rise table can be created in advance based on the above-mentioned formulas (1) and (2) and the relationship between the discharge or charge power of the battery 141 and the temperature rise.

[0040] The cooling amount specifying unit 174 estimates the cooling performance of the BTMS 142 based on the measurement data of the temperature and flow rate of the circulating water acquired by the data acquiring unit 171. The cooling amount specifying unit 174 estimates the cooling performance of the BTMS 142 from the flow rate, specific heat, and density of the circulating water, the temperature difference of the circulating water before and after the cooling pipe 1412, and the thermal resistance between the circulating water and the battery 141, and predicts the amount of temperature drop of the battery 141 per unit time. Note that the cooling amount specifying unit 174 may calculate the amount of temperature drop of the battery 141 based on the measurement data of the temperature of the circulating water and the measurement data of the temperature of the battery 141 acquired by the data acquiring unit 171. In this case, the amount of temperature drop of the battery 141 is the difference between the temperature of the battery 141 and the temperature of the circulating water.

[0041] The cooling control unit 175 determines a target temperature change amount of the battery 141 based on the target temperature of the battery 141, the current temperature of the battery 141, the temperature increase amount predicted by the heat generation amount prediction unit 173, and the temperature decrease amount identified by the cooling amount identification unit 174. The cooling control unit 175 outputs a control command to the BTMS control device 1428 based on the target temperature change amount. Note that the determination of the target temperature change amount may be performed by the heat generation amount prediction unit 173.

[0042] 7 is a diagram showing an example of a method for determining a control command for the BTMS 142 according to the first embodiment. Specifically, the cooling control unit 175 calculates the difference between the target temperature of the battery 141 and the current temperature of the battery 141 as a target temperature change amount ΔT ｔｇｔ The target temperature of the battery 141 is preferably a temperature at which the charge / discharge efficiency of the battery 141 is high and the deterioration rate is slow. For example, the target temperature may be determined in advance by multi-objective optimization of the charge / discharge efficiency and the deterioration rate. The cooling control unit 175 calculates the temperature rise ΔT predicted by the heat generation amount prediction unit 173. ｅｓｔ＋ and the temperature drop amount ΔT determined by the cooling amount determination unit 174 ｅｓｔ－ The difference between the predicted temperature change ΔT ｅｓｔ and the target temperature change amount ΔT ｔｇｔThe control amount of the cooling performance control command of the BTMS 142 is determined by multiplying the difference between the predicted temperature change and the target temperature change (indicated by the black arrow in FIG. 7 ) by a predetermined gain. The cooling performance control command may include, for example, a change in cooling performance (kcal / h). Specifically, if the predicted temperature change is greater than the target temperature change, that is, if the current cooling control would cause the temperature of the battery 141 to be higher than the target temperature, the cooling control unit 175 outputs a control command to improve the cooling performance. If the predicted temperature change is smaller than the target temperature change, that is, if the current cooling control would cause the temperature of the battery 141 to be lower than the target temperature, the cooling control unit 175 outputs a control command to decrease the cooling performance. Upon receiving the cooling performance control command, the BTMS control device 1428 changes the rotation speed of the fan 1427 and the discharge rate of the second pump 1426 according to the change in cooling performance indicated by the control command.

[0043] 8 is a flowchart showing a cooling control method for the battery 141 of the transport vehicle 10 by the transport system 1 according to the first embodiment. When the transport vehicle 10 starts traveling, the data acquisition unit 171 of the control device 163 acquires measurement data from various sensors (step S1). Specifically, the data acquisition unit 171 acquires at least measurement data on the position, traveling speed, and cargo weight of the transport vehicle 10 from the measurement device 161, measurement data on the temperature of the battery 141 from the battery monitoring device 1413, and measurement data on the temperature and flow rate of the circulating water from the BTMS control device 1428.

[0044] The gradient identification unit 172 transmits the measurement data of the current position of the haulage vehicle 10 acquired in step S1 to the management device 50 (step S2). When the management device 50 acquires the position measurement data from the haulage vehicle 10, it acquires information on the gradient at the position where the haulage vehicle 10 is located from the map shown in Fig. 2 and transmits the information on the gradient of the current position to the haulage vehicle 10. The gradient identification unit 172 receives the information on the gradient at the current position from the management device 50 (step S3).

[0045] The heat generation amount prediction unit 173 selects an estimated temperature rise table to be used for calculating the temperature rise amount based on the measurement data of the traveling speed and weight acquired in step S1 (step S4).The heat generation amount prediction unit 173 reads out the temperature rise amount associated with the gradient information received in step S3 from the selected estimated temperature rise table (step S5).

[0046] The cooling amount specifying unit 174 predicts the amount of temperature drop of the battery 141 based on the measurement data of the temperature and flow rate of the circulating water acquired in step S1 and the measurement data of the temperature of the battery 141 (step S6).

[0047] The cooling control unit 175 calculates the difference between a predetermined target temperature of the battery 141 and the current temperature of the battery 141 indicated by the measurement data acquired in step S1 as the target temperature change amount (step S7). The cooling control unit 175 calculates a predicted temperature change amount from the difference between the temperature increase amount calculated in step S5 and the temperature decrease amount calculated in step S6 (step S8). The cooling control unit 175 determines a control amount of the cooling performance by multiplying the difference between the predicted temperature change amount and the target temperature change amount by a predetermined gain G, and generates a control command for the cooling performance of the BTMS 142 (step S9). The cooling control unit 175 outputs the generated control command to the BTMS control device 1428 (step S10). The BTMS control device 1428 changes the target control amounts of the first pump 1425, the second pump 1426, and the fan 1427 in accordance with the control command. The BTMS control device 1428 drives the first pump 1425, the second pump 1426, and the fan 1427 in accordance with the changed target control amount. The control device 163 repeatedly executes the above process until the haulage vehicle 10 stops.

[0048] This allows the control device 163 to bring the temperature of the battery 141 closer to the target temperature.

[0049] <<Actions and Effects>> The haulage vehicle 10 according to the first embodiment includes a BTMS 142 that cools the battery 141 and a control device 163 that controls the BTMS 142 in accordance with the gradient of the work site where the haulage vehicle 10 is traveling. The amount of power required for powering the haulage vehicle 10 and the amount of regenerative power generated by braking vary depending on the gradient of the work site. Therefore, the control device 163 of the haulage vehicle 10 according to the first embodiment feeds forward the gradient of the work site to the cooling control of the BTMS 142, thereby controlling the cooling performance of the BTMS 142 to counteract heat generated by the battery 141 when traveling along the gradient-containing course C. For example, if the battery module is the only power source for driving the travel drive motor 131, heat generation from the battery 141 may increase when the haulage vehicle 10 travels up a steep slope. At this time, the control device 163 feeds forward the gradient of the work site to the cooling control of the BTMS 142, thereby controlling the cooling performance of the BTMS 142 so as to cancel out heat generation in the battery 141 due to traveling uphill with a steep gradient. Therefore, the transport vehicle 10 does not need to reduce its traveling speed to prevent a temperature rise in the battery 141. In other words, the transport vehicle 10 can prevent deterioration of the battery 141 without reducing work efficiency.

[0050] Other Embodiments Although one embodiment has been described in detail above with reference to the drawings, the specific configuration is not limited to the above, and various design modifications are possible. That is, in other embodiments, the order of the above-described processes may be changed as appropriate. Furthermore, some processes may be executed in parallel. The control device 163 according to the above-described embodiment may be configured by a single computer, or the configuration of the control device 163 may be divided into multiple computers, and the multiple computers may function as the control device 163 by cooperating with each other. In this case, some of the computers configuring the control device 163 may be installed inside the haulage vehicle 10, and other computers may be installed outside the haulage vehicle 10, such as the management device 50.

[0051] The control device 163 according to the embodiment described above predicts the amount of temperature rise in the battery 141 due to charging and discharging of the battery 141 based on the gradient of the work site, but is not limited to this. For example, the control device 163 according to another embodiment may generate a control command for the cooling performance of the BTMS 142 directly from the gradient of the work site without predicting the amount of temperature rise. For example, control commands according to the gradient may be prepared in advance, and the control device 163 may select a control command associated with the gradient of the work site and output it to the BTMS control device 1428.

[0052] The control device 163 according to the embodiment described above controls the BTMS 142 based on the current temperature of the battery 141, the temperature drop amount, which is the current cooling performance of the battery 141, and the predicted temperature rise amount, so that the temperature of the battery 141 approaches a predetermined target temperature, but is not limited to this. For example, the control device 163 according to another embodiment may output a control command according to the gradient of the work site, regardless of the current cooling performance of the battery 141.

[0053] The control device 163 according to the above-described embodiment transmits the position of the haulage vehicle 10 to the management device 50 and receives information on the gradient identified by the management device 50, but is not limited to this. For example, the control device 163 according to another embodiment may store the map shown in FIG. 2 and independently identify gradient information without querying the management device 50 about the gradient. The control device 163 according to another embodiment may measure the inclination angle of the haulage vehicle 10 using a sensor such as an IMU (Inertial Measurement Unit) and identify the gradient based on the measurement data of the inclination angle. By using the map, the control device 163 according to the above-described embodiment can identify the gradient without being affected by fluctuations or noise in the instantaneous values ​​of the measurement data.

[0054] Although the cooling device according to the above-described embodiment is a water-cooled BTMS 142 that cools circulating water with cooling water, the present invention is not limited to this. For example, a cooling device according to another embodiment may be an air-cooled BTMS 142 that does not include the intermediate heat exchanger 1421 and directly cools circulating water using the radiator 1422. Furthermore, a cooling device according to another embodiment may be, for example, a device that absorbs heat through a refrigeration cycle that uses a refrigerant such as ammonia or hydrocarbon, or may be an air blower that cools by blowing air.

[0055] The work vehicle according to the embodiment described above is a transport vehicle 10 such as a dump truck, but is not limited to this and may be other work vehicles such as a hydraulic excavator, a wheel loader, a bulldozer, or a forklift.

[0056] The work machine in the above-described embodiment is a dump body, but is not limited to this. For example, if the work vehicle is a hydraulic excavator, it may be a boom, an arm, and an attachment. For example, if the work vehicle is a wheel loader, it may be a bucket and an operation instruction unit that changes the bucket position and attitude. For example, if the work vehicle is a forklift, it may be a mast, a bracket, and a fork.

[0057] <Computer Configuration> Fig. 9 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. The computer 90 includes a processor 91, a main memory 93, a storage 95, and an interface 97. The control device 163 described above is implemented in the computer 90. The operations of each of the processing units described above are stored in the storage 95 in the form of a program. The processor 91 reads the program from the storage 95, loads it into the main memory 93, and executes the above-described processing in accordance with the program. The processor 91 also allocates storage areas in the main memory 93 corresponding to each of the storage units described above in accordance with the program. Examples of the processor 91 include a CPU (Central Processing Unit), a GPU (Graphic Processing Unit), and a microprocessor.

[0058] The program may be for implementing some of the functions to be performed by the computer 90. For example, the program may be implemented in combination with other programs already stored in storage or in combination with other programs implemented in other devices. In another embodiment, the computer 90 may include a custom large-scale integrated circuit (LSI) such as a programmable logic device (PLD) in addition to or instead of the above configuration. Examples of PLDs include programmable array logic (PAL), generic array logic (GAL), complex programmable logic device (CPLD), and field programmable gate array (FPGA). In this case, some or all of the functions implemented by the processor 91 may be implemented by the integrated circuit. Such an integrated circuit is also an example of a processor. In another embodiment, the computer 90 may be virtualized on one or more computers.

[0059] Examples of storage 95 include a magnetic disk, a magneto-optical disk, an optical disk, and a semiconductor memory. Storage 95 may be an internal medium directly connected to the bus of computer 90, or an external medium connected to computer 90 via interface 97 or a communication line. Furthermore, when this program is distributed to computer 90 via a communication line, computer 90 that receives the program may load the program into main memory 93 and execute the above-described processing. In at least one embodiment, storage 95 is a non-transitory tangible storage medium.

[0060] The program may also be a program for realizing some of the above-described functions. Furthermore, the program may be a so-called differential file (differential program) that realizes the above-described functions in combination with another program already stored in storage 95.

[0061] According to the above aspect, the work vehicle can prevent battery deterioration without reducing work efficiency.

[0062] 1...Transportation system 10...Transportation vehicle 11...Dump body 12...Vehicle body 13...Travel device 131...Travel drive motor 14...Battery module 141...Battery 1411...Battery main body 1412...Cooling pipe 1413...Battery monitoring device 142...BTMS 1421...Intermediate heat exchanger 1422...Radiator 1423...First flow path 1424...Second flow path 1425...First pump 1426...Second pump 1427...Fan 1428...BTMS control device 1429...Circulating water sensor 16...Control system 161...Measuring device 162...Communication device 163...Control device 164...Operation device 165...Monitor 171...Data acquisition unit 172...Slope identification unit 173...Heat generation amount prediction unit 174...Cooling amount identification unit 175...Cooling control unit 30...Loading machine 50... Management device 90... Computer 91... Processor 93... Main memory 95... Storage 97... Interface C... Course P1... Mining site P2... Soil disposal site

Claims

1. A work vehicle having a work implement and traveling on a work site using power supplied from a battery, the work vehicle comprising: a cooling device that cools the battery; and a control device that controls the cooling device in accordance with the gradient of the work site on which the work vehicle is traveling.

2. The work vehicle according to claim 1, wherein the control device controls the cooling device based on the current temperature of the battery and the gradient of the work site.

3. The work vehicle according to claim 2, wherein the control device further controls the cooling device based on the weight of a load on the work vehicle.

4. The work vehicle according to claim 1, wherein the control device predicts the amount of temperature rise of the battery due to charging and discharging of the battery based on the gradient of the work site, and controls the cooling device based on the current temperature of the battery and the amount of temperature rise.

5. The work vehicle according to claim 2 or claim 4, wherein the control device further controls the cooling device based on a current cooling performance of the cooling device.

6. A work vehicle according to claim 1, further comprising a positioning device that measures the position of the work vehicle, and the control device identifies the gradient of the work site based on the position of the work vehicle.

7. The work vehicle according to claim 1, wherein the control device controls the cooling performance of the cooling device.

8. The work vehicle according to claim 1, wherein the cooling device supplies a refrigerant for cooling the battery, and the control device determines a current cooling performance of the cooling device based on a current temperature and flow rate of the refrigerant.

9. A control method for a work vehicle that is equipped with a battery and a cooling device that cools the battery and that travels through a work site using power supplied from the battery, the control method comprising a step in which the control device controls the cooling performance of the battery in accordance with the gradient of the work site through which the work vehicle is traveling.

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