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

Title of Invention WORK VEHICLE AND METHOD FOR CONTROLLING WORK VEHICLE Technical Field

[0001] The present disclosure relates to a work vehicle and a method for controlling a work vehicle. The present application claims priority to Japanese Patent Application No. 2024-056374 filed in Japan on March 29, 2024, the contents of which are incorporated herein by reference . Background Art

[0002] There is a work vehicle that is provided with a battery and is driven by electric power supplied from the battery. It is known that a battery generates heat by charging and discharging and deteriorates as the temperature increases .

[0003] Patent Literature 1 discloses a technique that has a function of displaying a recommended traveling speed for minimizing damage to a vehicle body in a transport vehicle and maintains transport efficiency while reducing damage from a road surface caused by traveling. Patent Literature 2 discloses a technique for limiting a traveling speed of an engine-driven transport vehicle even when an accelerator pedal is depressed for the purpose of reducing damage to a vehicle body, improving engine durability, and the like. Citation List Patent Literature

[0004] Patent Literature 1: JP 6744887 B2 Patent Literature 2: JP 3212234 B2 Summary of Invention Technical Problem

[0005] In these techniques for limiting output of a vehicle as in Patent Literature 1 and Patent Literature 2 in order to prevent a temperature increase of a battery, work efficiency is reduced. An object of the present disclosure is to provide a work vehicle and a method for controlling a work vehicle that can prevent a deterioration of a battery without reducing work efficiency. Solution to Problem

[0006] According to one aspect of the present disclosure, there is provided a work vehicle that is provided with a work machine and travels at a work site with electric power supplied from a battery, the work vehicle including: a cooling control unit that controls cooling performance for the battery according to a gradient of the work site at which the work vehicle travels. Advantageous Effects of Invention

[0007] According to the above aspect, the work vehicle can prevent a deterioration of the battery without reducing work efficiency. Brief Description of Drawings

[0008] Fig. 1 is a diagram illustrating a configuration of a transport system including a transport vehicle according to a first embodiment. Fig. 2 is a diagram illustrating an example of a map according to the first embodiment. Fig. 3 is a perspective view schematically illustrating the transport vehicle according to the first embodiment. Fig. 4 is a diagram illustrating a configuration of a battery module according to the first embodiment. Fig. 5 is a schematic block diagram illustrating a configuration of a control system included in the transport vehicle according to the first embodiment. Fig. 6 is a diagram illustrating an example of an estimated temperature increase table according to the first embodiment. Fig. 7 is a diagram illustrating an example of a method of determining a control command of a BTMS according to the first embodiment. Fig. 8 is a flowchart illustrating a cooling control method of a battery of the transport vehicle by the transport system according to the first embodiment. Fig. 9 is a schematic block diagram illustrating a configuration of a computer according to at least one embodiment. Description of Embodiments

[0009] <First Embodiment> <<Transport System 1>> Hereinafter, embodiments will be described in detail with reference to the drawings. Fig. 1 is a diagram illustrating a configuration of a transport system 1 including a transport vehicle 10 according to a first embodiment. The transport system 1 includes a plurality of transport vehicles 10 and a management device 50. The transport system 1 is used to transport loads such as earth and sand, crushed stones, and the like mined using the plurality of transport vehicles 10. The management device 50 collects data from the transport vehicle 10, and manages a work situation of the transport vehicle 10. The transport vehicle 10 is an example of a work vehicle.

[0010] In a work site, a mining site Pl and a soil unloading site P2 are provided. The transport vehicle 10 loads a load by a loading machine 30 at the mining site Pl, transports the load to the soil unloading site P2, and unloads the load at the soil unloading site P2. The loading machine 30 may be, for example, a hydraulic excavator or a wheel loader. When the load is unloaded at the soil unloading site P2, the transport vehicle 10 moves to the mining site Pl again, and loads a load. A course C for traveling of the transport vehicle 10 is provided at the work site. The course C may be a one-way road as illustrated in Fig. 1 or a two-way road.

[0011] «Management Device 50>> The management device 50 acquires pieces of measurement data such as a position, a direction, a traveling speed, and a weight of a load, from the plurality of transport vehicles 10, and manages a work situation of each transport vehicle 10. The management device 50 transmits operation data for instructing each transport vehicle 10 on a traveling route according to the work situation of the transport vehicle 10. The operation data may be data for instructing an operator on a route on which the transport vehicle 10 which is a manned vehicle is to travel, or may be data for controlling traveling of the transport 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 a map according to the first embodiment. The map according to the first embodiment is obtained by dividing the work site into a plurality of areas by a mesh and associating traveling route information indicating whether each area is in the course C or outside a traveling range. The area related to the course C is further associated with gradient information. The gradient information takes any value of a large downward gradient, a small downward gradient, a flat surface, a small upward gradient, and a large upward gradient. Note that, in the work site according to the first embodiment, since the course C is a one-way road, whether the road is an upward road or a downward road is associated as gradient information. The gradient information of the map according to another embodiment may be associated with a combination of a degree of the gradient and a direction of the gradient. In this case, it is possible to determine whether the road has an upward gradient or a downward gradient from a direction in which the transport vehicle 10 faces the road even in a case where the road is a two-way road. In addition, in the gradient information of the map according to the first embodiment, the degree of the gradient is classified into large / small / flat, but is not limited thereto. The degree of the gradient may be represented by a numerical value such as an inclination angle or a percentage in another embodiment.

[0013] When acquiring the measurement data of the position from the transport vehicle 10, the management device 50 acquires gradient information at a position at which the transport vehicle 10 is present from the map illustrated in Fig. 2, and notifies the transport vehicle 10 of the gradient of the current position.

[0014] <<Transport Vehicle 10>> Fig. 3 is a perspective view schematically illustrating the transport vehicle 10 according to the first embodiment. The transport 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 performs a dumping operation and a lowering operation by an actuator (not illustrated). The dump body 11 is adjusted to a dumping posture and a loading posture by the dumping operation and the lowering operation. The dumping posture refers to a posture in which the dump body 11 is raised. The loading 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 a hydraulic motor driven by hydraulic oil supplied from a hydraulic pump driven by a drive motor for an electric pump. The dump body 11 is an example of a work machine.

[0016] The dumping operation refers to an operation of separating the dump body 11 from the vehicle body 12 and inclining the dump body 11 in a dump direction. The dump direction is a rear side of the vehicle body 12. In the embodiment, the dumping operation includes raising a front end portion of the dump body 11 and inclining the dump body 11 toward the rear side. By the dumping operation, a loading surface of the dump body 11 is inclined downward toward the rear side.

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

[0018] In a case where soil unloading work is performed, the dump body 11 performs a dumping operation such that the posture changes from the loading posture to the dumping posture. In a case where a load is loaded on the dump body 11, the load is discharged toward the rear side from a rear end portion of the dump body 11 by the dumping operation. In a case where loading work is performed, the dump body 11 is adjusted to the loading posture.

[0019] The vehicle body 12 includes a vehicle body frame. The vehicle body 12 supports the dump body 11. The vehicle body 12 is supported by the 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 moves the transport vehicle 10 forward or rearward. At least a portion of the traveling device 13 is disposed below the vehicle body 12. The traveling device 13 includes a pair of front wheels and a pair of rear wheels. The front wheel is a steering wheel, and the rear wheel is a driving wheel. Note that the combination of the steering wheels and the driving wheels is not limited thereto, and the traveling device 13 may be four-wheel drive or four-wheel steering. The traveling device 13 includes 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 which is an electric power source for driving the actuator of the dump body 11 and the traveling drive motor 131 of the traveling device 13. Note that a plurality of battery modules 14 may be provided.

[0022] Fig. 4 is a diagram illustrating a configuration of the 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 charging / discharging efficiency varies depending on an operation temperature level. Thus, it is necessary to adjust a temperature of the battery 141. The BTMS 142 is a system for controlling a 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, but the present disclosure is not limited thereto. In another embodiment, the number of batteries 141 and BTMS 142 may be different. For example, one BTMS 142 may control temperatures of a plurality of batteries 141. Further, for example, in a case where a plurality of battery modules 14 are provided, the BTMS 142 of a certain battery module 14 may control a temperature of the battery 141 included in a different 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 which passes through a housing of the battery 141 and through which circulating water supplied from the BTMS 142 flows. By allowing the circulating water to flow through the cooling pipe 1412, heat is exchanged between the battery main body 1411 and the circulating water. 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 a state of the battery 141. Specifically, the battery monitoring device 1413 acquires a temperature, a charging rate, a voltage, and the like of the battery 141 from a sensor 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 a primary side and a secondary side, and exchanges heat between the cooling water flowing toward the primary side and the circulating water flowing toward the secondary side. In the present embodiment, a side on which a cooling source, that is, the radiator 1422 is present is referred to as the primary side, and a side on which a cooling target, that is, the battery main body 1411 is present is referred to as the secondary side. The radiator 1422 allows the cooling water to pass therethrough, and releases heat of the cooling water to the outside air. The first flow path 1423 is connected such that the circulating water circulates between the cooling pipe 1412 of the battery 141 and the flow path of the intermediate heat exchanger 1421 on the secondary side. A circulating water sensor 1429 that measures a temperature and a flow rate of the circulating water is provided in the first flow path 1423. The circulating water sensors 1429 are respectively provided on an upstream side and a downstream side of the cooling pipe 1412. The second flow path 1424 is connected such that the cooling water circulates between the flow path of the intermediate heat exchanger 1421 on the primary side and the radiator 1422. The cooling water flows through the second flow path 1424. 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 promotes heat exchange in the radiator 1422 by blowing air to the radiator 1422. The BTMS control device 1428 receives a control command, and controls the first pump 1425, the second pump 1426, and the fan 1427 according to the control command. The BTMS control device 1428 outputs the pieces of measurement data of the temperature and the flow rate of the circulating water, the measurement data being measured by the circulating water sensor 1429.

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

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

[0029] The measurement device 161 measures a state of the transport vehicle 10 by various sensors, and generates pieces of measurement data. Specifically, the measurement device 161 includes a positioning sensor (positioning device) that measures a position and a direction of the transport vehicle 10 based on a signal from a global navigation satellite system (GNSS), a speed sensor that measures a traveling speed of the transport vehicle 10, and a payload meter that measures a weight of a load of the transport vehicle 10.

[0030] The communication device 162 performs communication with the management device 50 through a mobile communication network or the like. The communication device 162 transmits the pieces of measurement data measured by the measurement device 161 to the management device 50. The communication device 162 receives operation data related to the operation of the transport vehicle 10 from the management device 50. The operation data may be data for instructing an operator on a route on which the transport vehicle 10 which is a manned vehicle is to travel, or may be data for controlling traveling of the transport vehicle 10 which is an unmanned vehicle. The operation data includes at least a gradient at a position at which the transport vehicle 10 is present.

[0031] The control device 163 drives the transport vehicle 10 according to control data received by the communication device 162 from the management device 50 and the operation amount of the operation device 164. The operation device 164 is provided in an operator's cab, and receives an operation by an operator. The operation device 164 includes an accelerator pedal, a brake pedal, a steering wheel, a dump lever, and the like. The monitor 165 is provided in the operator's cab, and displays a traveling route and the like for the operator .

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

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

[0034] The gradient specifying unit 172 specifies a gradient of the current position based on the pieces of measurement data of the current position and the direction of the transport vehicle 10, the measurement data being acquired by the data acquisition unit 171. Specifically, the gradient specifying unit 172 specifies a gradient by transmitting the measurement data of the current position to the management device 50 and receiving the gradient information at the current position from the management device 50.

[0035] The heat generation amount prediction unit 173 predicts a temperature increase amount of the battery 141 due to charging and discharging of the battery 141 based on the gradient specified by the gradient specifying unit 172. The temperature increase amount of the battery 141 is a temperature difference between the temperature of the battery 141 that is predicted based on the gradient specified by the gradient specifying unit 172 and the temperature of the cooling water. That is, the heat generation amount prediction unit 173 predicts the temperature increase amount of the battery 141 when discharging the electric power required for powering of the transport vehicle 10 from the battery 141, based on the gradient specified by the gradient specifying unit 172. The heat generation amount prediction unit 173 predicts the temperature increase amount of the battery 141 when the battery 141 is charged with regenerative power generated by braking of the transport vehicle 10, based on the gradient specified by the gradient specifying unit 172. The heat generation amount prediction unit 173 stores in advance an estimated temperature increase table for obtaining the temperature increase amount of the battery 141 from the traveling speed, the weight of the load, and the gradient, and obtains the temperature increase amount from the pieces of measurement data acquired by the data acquisition unit 171. Note that, in a case where the transport vehicle 10 always travels at a speed limit which is set for the course C, the estimated temperature increase table may not have a variable for the traveling speed.

[0036] Fig. 6 is a diagram illustrating an example of the estimated temperature increase table according to the first embodiment. The estimated temperature increase table shows a relationship between the gradient and the temperature increase amount. Specifically, the estimated temperature increase table is a table in which the temperature increase amount is associated with each of a large upward gradient, a small upward gradient, a flat surface, a small downward gradient, and a large downward gradient. The estimated temperature increase table is prepared for each combination of the weight and the traveling speed of the transport vehicle 10. For example, the heat generation amount prediction unit 173 may have four patterns of estimated temperature increase tables related to combinations of the presence or absence of the load (the weight of the transport vehicle 10) and a level of the traveling speed.

[0037] Here, the estimated temperature increase table will be described. The energy Ei required for powering of the transport vehicle 10 can be obtained by the following expression (1). In addition, the energy E2 generated by braking of the transport vehicle 10 can be obtained by the following expression (2). Here, M represents the weight of the transport vehicle 10, v represents the traveling speed of the transport vehicle 10, 9 represents the gradient, Cr represents a rolling resistance coefficient, and Ca represents an air resistance coefficient.

[0038] [Mathematical Formula 1] E' = (Mg sin e + CrMg + Qv2 )v ■ • ■ (1) [Mathematical Formula 2] E-, = (Mg sin e - CrMg - Cav2 )v ---(2)

[0039] The discharging power or the charging power of the battery 141 can be obtained by obtaining power conversion efficiency of the traveling device, charging / discharging efficiency of the battery, input / output efficiency of an electric circuit between the traveling device and the battery, and the like in advance, and using these factors, drive efficiency, and the energy E. A relationship between the discharging power or the charging power of the battery 141 and the temperature increase amount of the battery 141 can be calculated based on a design value corresponding to a type of the battery 141. For example, the temperature increase amount of the battery 141 can be obtained from the discharging power or the charging power of the battery 141, the charging / discharging efficiency of the battery 141, and the thermal resistance between the circulating water and the battery 141. Note that the thermal resistance between the circulating water and the battery 141 is obtained by adding 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, it is possible to create the estimated temperature increase table in advance from the expression (1) and the expression (2) described above and the relationship between the discharging power or the charging power of the battery 141 and the temperature increase amount.

[0040] The cooling amount specifying unit 174 estimates cooling performance of the BTMS 142 based on the pieces of measurement data of the temperature and the flow rate of the circulating water, the measurement data being acquired by the data acquisition unit 171. The cooling amount specifying unit 174 estimates cooling performance of the BTMS 142 from the flow rate, the specific heat, and the density of the circulating water, a 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 a temperature decrease amount of the battery 141 per unit time. Note that the cooling amount specifying unit 174 may calculate a temperature decrease amount 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, the measurement data being acquired by the data acquisition unit 171. At this time, the temperature decrease amount of the battery 141 is a 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 a target temperature of the battery 141, a current temperature of the battery 141, the temperature increase amount predicted by the heat generation amount prediction unit 173, and the temperature decrease amount specified by the cooling amount specifying 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 target temperature change amount may be determined by the heat generation amount prediction unit 173 .

[0042] Fig. 7 is a diagram illustrating an example of a method of determining a control command of the BTMS 142 according to the first embodiment. Specifically, the cooling control unit 175 obtains, as the target temperature change amount ATtgtf a difference between the target temperature of the battery 141 and the current temperature of the battery 141. The target temperature of the battery 141 is preferably a temperature at which the charging / discharging efficiency of the battery 141 is high and a degradation rate of the battery 141 is slow. For example, the target temperature may be determined in advance by multi-objective optimization of the charging / discharging efficiency, the degradation rate, and the like. The cooling control unit 175 determines a control amount of a control command of the cooling performance of the BTMS 142 by multiplying a difference (a black arrow in Fig. 7) between a predicted temperature change amount ATest and the target temperature change amount ATtgt by a predetermined gain, the predicted temperature change amount ATest being indicated by a difference between the temperature increase amount ATest+ predicted by the heat generation amount prediction unit 173 and the temperature decrease amount ATest- specified by the cooling amount specifying unit 174. The control command of the cooling performance may include, for example, a change amount (kcal / h) of the cooling performance. Specifically, in a case where the predicted temperature change amount is larger than the target temperature change amount, that is, in a case where the temperature of the battery 141 becomes higher than the target temperature in the current cooling control, the cooling control unit 175 outputs a control command for increasing the cooling performance. In a case where the predicted temperature change amount is smaller than the target temperature change amount, that is, in a case where the temperature of the battery 141 becomes lower than the target temperature in the current cooling control, the cooling control unit 175 outputs a control command for decreasing the cooling performance. When receiving the control command of the cooling performance, the BTMS control device 1428 changes a rotation speed of the fan 1427 and a discharge amount of the second pump 1426 according to the change amount of the cooling performance that is indicated by the control command.

[0043] <<Cooling Control of Battery 141>> Fig. 8 is a flowchart illustrating a cooling control method of 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 pieces of measurement data from various sensors (step SI). Specifically, the data acquisition unit 171 acquires pieces of measurement data of the position, the traveling speed, and the weight of the load of the transport vehicle 10 from at least the measurement device 161, acquires measurement data of the temperature of the battery 141 from the battery monitoring device 1413, and acquires pieces of measurement data of the temperature and the flow rate of the circulating water from the BTMS control device 1428.

[0044] The gradient specifying unit 172 transmits the measurement data of the current position of the transport vehicle 10 acquired in step SI to the management device 50 (step S2) . When acquiring the measurement data of the position from the transport vehicle 10, the management device 50 acquires gradient information at the position at which the transport vehicle 10 is present from the map illustrated in Fig. 2, and transmits the gradient information of the current position to the transport vehicle 10. The gradient specifying unit 172 receives the gradient information at the current position from the management device 50 (step S3).

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

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

[0047] The cooling control unit 175 obtains, as a target temperature change amount, a difference between a predetermined target temperature of the battery 141 and a current temperature of the battery 141 indicated by the measurement data acquired in step SI (step S7). The cooling control unit 175 obtains a predicted temperature change amount from a difference between the temperature increase amount obtained in step S5 and the temperature decrease amount obtained in step S6 (step S8). The cooling control unit 175 determines a control amount of the cooling performance by multiplying a difference between the predicted temperature change amount and the target temperature change amount by a predetermined gain G, and generates a control command of 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 target control amounts of the first pump 1425, the second pump 1426, and the fan 1427 according to the control command. The BTMS control device 1428 drives the first pump 1425, the second pump 1426, and the fan 1427 according to the changed target control amounts. The control device 163 repeatedly executes the above processing until the transport vehicle 10 stops.

[0048] Thereby, the control device 163 can perform control such that the temperature of the battery 141 approaches the target temperature.

[0049] <<Operation and Effect>> The transport vehicle 10 according to the first embodiment includes the BTMS 142 that cools the battery 141, and the control device 163 that controls the BTMS 142 according to a gradient of a work site at which the transport vehicle 10 travels. The level of the power required for powering of the transport vehicle 10 and the level of the regenerative power generated by braking of the transport vehicle 10 change depending on the gradient of the work site. Therefore, the control device 163 of the transport vehicle 10 according to the first embodiment can control the cooling performance of the BTMS 142 so as to cancel heat generation of the battery 141 due to traveling of the course C having the gradient by feeding forward the gradient of the work site to the cooling control of the BTMS 142. For example, in a case where the power source for driving the traveling drive motor 131 is only the battery module, heat generation of the battery 141 may increase when the transport vehicle 10 travels on an uphill road having a large gradient. At this time, the control device 163 can control the cooling performance of the BTMS 142 so as to cancel heat generation of the battery 141 due to traveling on an uphill road having a large gradient by feeding forward the gradient of the work site to the cooling control of the BTMS 142. Therefore, the transport vehicle 10 does not need to limit the traveling speed in order to prevent a temperature increase of the battery 141. That is, the transport vehicle 10 can prevent a deterioration of the battery 141 without reducing work efficiency .

[0050] <Other Embodiments> Although one embodiment has been described in detail with reference to the drawings, the specific configuration is not limited to the above, and various design changes and the like can be made. That is, in other embodiments, the order of the above-described processing may be appropriately changed. In addition, some processes may be executed in parallel. The control device 163 according to the abovedescribed embodiment may be configured by a single computer, or the configuration of the control device 163 may be divided into a plurality of computers and the plurality of computers may function as the control device 163 in cooperation with each other. At this time, some computers included in the control device 163 may be provided in the transport vehicle 10, and other computers may be provided in a device outside the transport vehicle 10, such as the management device 50.

[0051] The control device 163 according to the abovedescribed embodiment predicts the temperature increase amount of the battery 141 due to charging and discharging of the battery 141 based on the gradient of the work site, but the present disclosure is not limited thereto. For example, the control device 163 according to other embodiments may generate a control command of the cooling performance of the BTMS 142 directly from the gradient of the work site without predicting the temperature increase amount. For example, a control command corresponding 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 the control command to the BTMS control device 1428.

[0052] The control device 163 according to the abovedescribed embodiment controls the BTMS 142 such that the temperature of the battery 141 approaches a predetermined target temperature based on the current temperature of the battery 141, the temperature decrease amount which corresponds to the current cooling performance for the battery 141, and the predicted temperature increase amount, but the present disclosure is not limited thereto. For example, the control device 163 according to other embodiments may output a control command according to the gradient of the work site regardless of the current cooling performance for the battery 141.

[0053] The control device 163 according to the abovedescribed embodiment transmits the position of the transport vehicle 10 to the management device 50 and receives the gradient information specified by the management device 50, but the present disclosure is not limited thereto. For example, the control device 163 according to other embodiments may store the map illustrated in Fig. 2, and independently specify gradient information without inquiring the gradient to the management device 50. In addition, the control device 163 according to other embodiments may measure an inclination angle of the transport vehicle 10 by a sensor such as an inertial measurement unit (IMU), and specify a gradient based on measurement data of the inclination angle. Note that the control device 163 according to the abovedescribed embodiment can specify the gradient by using the map without being affected by a fluctuation or noise in an instantaneous value of the measurement data.

[0054] The cooling device according to the above-described embodiment is a water-cooling-type BTMS 142 that cools circulating water by cooling water, but the present disclosure is not limited thereto. For example, the cooling device according to other embodiments may be an air-cooling-type BTMS 142 that directly cools circulating water by the radiator 1422 without the intermediate heat exchanger 1421. Further, the cooling device according to other embodiments may be, for example, a device that absorbs heat by a refrigeration cycle using a coolant such as ammonia or hydrocarbon, or may be a blower that performs cooling by blowing air.

[0055] The work vehicle according to the above-described embodiment is the transport vehicle 10 such as a dump truck, but the present disclosure is not limited thereto. Another work vehicle such as a hydraulic excavator, a wheel loader, a bulldozer, or a forklift may be used.

[0056] The work machine according to the above-described embodiment is a dump body, but the present disclosure is not limited thereto. For example, in a case where the work vehicle is a hydraulic excavator, the work machine may be a boom, an arm, or an attachment. For example, in a case where the work vehicle is a wheel loader, the work machine may include a bucket and an operation instructing unit that changes a position and a posture of the bucket. For example, in a case where the work vehicle is a forklift, the work machine may include a mast, a bracket, and a fork.

[0057] <Computer Configuration> Fig. 9 is a schematic block diagram illustrating a 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 above-described control device 163 is implemented in the computer 90. In addition, an operation of each processing unit described above is stored in the storage 95 in a form of a program. The processor 91 reads the program from the storage 95, develops the program in the main memory 93, and executes the above processing according to the program. Further, the processor 91 secures, in the main memory 93, a storage area corresponding to each storage unit described above, according to the program. Examples of the processor 91 include a central processing unit (CPU), a graphic processing unit (GPU), and a microprocessor.

[0058] The program may be for implementing some of the functions to be exhibited by the computer 90. For example, the program may exhibit a function by a combination with another program already stored in the storage or a combination with another program provided in another device. Note that, in other embodiments, 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 the PLD include a programmable array logic (PAL), a generic array logic (GAL), a complex programmable logic device (CPLD), and a 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 included in an example of the processor. Further, in other embodiments, the computer 90 may be virtualized on one or more computers.

[0059] Examples of the storage 95 include a magnetic disk, a magneto-optical disk, an optical disk, a semiconductor memory, and the like. The storage 95 may be an internal medium directly connected to a bus of the computer 90, or may be an external medium connected to the computer 90 through the interface 97 or a communication line. Further, in a case where the program is distributed to the computer 90 through a communication line, the computer 90 that has received the distribution may develop the program in the main memory 93, and execute the above processing. In at least one embodiment, the storage 95 is a non-transitory tangible storage medium.

[0060] In addition, the program may be for implementing some of the functions described above. Further, the program may be a program that implements the abovedescribed functions in combination with another program already stored in the storage 95, that is, a so-called difference file (difference program). Industrial Applicability

[0061] According to the above aspect, the work vehicle can prevent a deterioration of the battery without reducing work efficiency. Reference Signs List

[0062] 1 Transport system 10 Transport vehicle 11 Dump body 12 Vehicle body 13 Traveling device 131 Traveling 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 Second pump Fan BTMS control device Circulating water sensor Control system Measurement device Communication device Control device Operation device Monitor Data acquisition unit Gradient specifying unit Heat generation amount prediction unit Cooling amount specifying unit Cooling control unit Loading machine Management device Computer Processor Main memory Storage Interface Course Mining site Soil unloading site

Claims

1. A work vehicle that is provided with a work machine and travels at a work site with electric power supplied from a battery, the work vehicle comprising:a cooling device that cools the battery; anda control device that controls the cooling device according to a gradient of the work site at which the work vehicle travels.

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

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

4. The work vehicle according to claim 1, wherein the control device is configured to: predict a temperature increase amount of the battery due to charging and discharging of the battery, based on the gradient of the work site; andcontrol the cooling device based on a currenttemperature of the battery and the temperature increase amount of the battery.

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

6. The work vehicle according to claim 1, further comprising :a positioning device that measures a position of the work vehicle, whereinthe control device specifies the gradient of the work site based on a position of the work vehicle.

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

8. The work vehicle according to claim 1, whereinthe cooling device supplies a coolant for cooling the battery, andthe control device specifies current cooling performance of the cooling device based on a current temperature and a flow rate of the coolant.

9. A method for controlling a work vehicle that includes a battery and a cooling device and travels at a work site with electric power supplied from the battery, the cooling device being provided to cool the battery, the method comprising:a step of controlling, by a control device, cooling performance for the battery according to a gradient of the work site at which the work vehicle travels.

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