Battery system

Abstract

To provide a technique capable of suppressing deterioration in a battery system even during travel of a vehicle and capable of making the battery system compact.SOLUTION: A battery system includes: a battery for driving a vehicle including a plurality of battery cells; a transport device capable of moving the plurality of battery cells at least while the vehicle is traveling; and a control device that determines whether or not to move the plurality of battery cells based on a use state of the battery for driving.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a battery system. [Background technology]

[0002] In recent years, electric vehicles have been put to practical use. These vehicles run on drive torque obtained by rotating a drive motor using electric power stored in a drive battery. In electric vehicles, if the drive battery operates at temperatures exceeding the operating temperature range, the performance of the drive battery may deteriorate. Therefore, it is important to suppress the deterioration of the drive battery due to heat.

[0003] For example, Patent Document 1 discloses that when partial deterioration of the electrochemical cells and fuel cell stack is detected, the fuel cell stack is rearranged by swapping it upside down and left to right, thereby suppressing uneven deterioration due to the reactant gas concentration distribution and temperature distribution in the stacking direction within the fuel cell stack, or the temperature distribution within the insulated box that houses the fuel cell stack.

[0004] Furthermore, for example, Patent Document 2 discloses a battery unit that moves an insulating material to separate a battery cell arranged above a heat-generating component from the battery cell when the temperature of the battery cell exceeds a predetermined temperature, and moves the insulating material to cover the battery cell from above when the temperature of the battery cell falls below the predetermined temperature. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent Publication No. 2021-136103 [Patent Document 2] Patent No. 6777031 Summary of the Invention [Problem to be solved by the invention]

[0006] In Patent Document 1, rearrangement of the fuel cell stack is performed as a maintenance task, which requires the removal of various components that make up the fuel cell stack. Therefore, rearrangement of the fuel cell stack cannot be performed while the vehicle is running. In Patent Document 2, the impact of heat from heat-generating components such as the exhaust pipe of a hybrid vehicle on the battery unit can be suppressed. However, since heat insulation is required for the battery unit, it is difficult to achieve compactness.

[0007] The purpose of the present disclosure, made in consideration of these circumstances, is to provide technology that can suppress deterioration of a battery system even while a vehicle is running and that can make the battery system more compact. [Means for solving the problem]

[0008] A battery system according to one embodiment of the present disclosure includes a vehicle drive battery including a plurality of battery cells, a transport device capable of moving the plurality of battery cells at least while the vehicle is moving, and a control device that determines whether to move the plurality of battery cells based on the usage status of the drive battery. [Effects of the Invention]

[0009] According to one embodiment of the present disclosure, it is possible to suppress deterioration of a battery system even while a vehicle is traveling, and to make the battery system more compact. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a schematic diagram illustrating an example configuration of a vehicle to which a battery system according to a first embodiment of the present disclosure can be applied. [Figure 2] 1 is a schematic diagram illustrating a configuration example of a battery system according to a first embodiment of the present disclosure. [Figure 3] 1 is a schematic diagram illustrating a configuration example of a transport device included in a battery system according to a first embodiment of the present disclosure. [Figure 4]1 is a schematic diagram illustrating a configuration example of a trolley wire included in a battery system according to a first embodiment of the present disclosure. [Figure 5] 1 is a schematic diagram illustrating a configuration example of a trolley wire included in a battery system according to a first embodiment of the present disclosure. [Figure 6] 1 is a block diagram showing a configuration example of a control device included in a battery system according to a first embodiment of the present disclosure. [Figure 7] 4 is a graph illustrating charging and discharging of a driving battery provided in a battery system according to a first embodiment of the present disclosure. [Figure 8] 4 is a graph illustrating temperature changes of a battery cell included in a battery system according to a first embodiment of the present disclosure. [Figure 9] 4 is a graph illustrating the temperature distribution of a battery cell included in a battery system according to a first embodiment of the present disclosure. [Figure 10] 3A and 3B are diagrams illustrating the movement of battery cells by a transport device included in a battery system according to a first embodiment of the present disclosure. [Figure 11] 5 is a flowchart showing an example of the operation of a control device included in the battery system according to the first embodiment of the present disclosure. [Figure 12] 12 is a graph illustrating how the operational example shown in FIG. 11 reduces variations in temperature distribution of the battery cells. [Figure 13] FIG. 4 is a schematic diagram showing a general configuration of a battery system according to a second embodiment of the present disclosure. [Figure 14] 10 is a flowchart showing an example of the operation of a control device included in a battery system according to a second embodiment of the present disclosure. [Figure 15] FIG. 4 is a schematic diagram showing a configuration example of a battery system according to a first modified example of the present disclosure. [Figure 16] FIG. 10 is a schematic diagram showing a configuration example of a battery system according to a second modification of the present disclosure. [Figure 17] FIG. 10 is a schematic diagram showing a configuration example of a battery module included in a battery system according to a second modification of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, preferred embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. In this specification and drawings, components having substantially the same functional configurations are designated by the same reference numerals, and redundant description will be omitted.

[0012] First Embodiment (Overall vehicle configuration) Referring to FIG. 1, vehicle 1000 includes a drive system 100, a brake system 200, a vehicle state sensor 300, and a battery system 400. Vehicle 1000 is a four-wheel electric vehicle with front, rear, left, and right wheels. Vehicle 1000 is a two-wheel drive four-wheel vehicle in which drive torque output from a drive motor 110, which serves as a drive power source that generates drive torque, is transmitted to the front wheels. Vehicle 1000 may also be a four-wheel drive vehicle in which drive torque is transmitted to the front and rear wheels. Vehicle 1000 may also be a hybrid electric vehicle in which a drive battery 410 (described later) can be charged using power generated by a generator.

[0013] The drive system 100 includes a drive motor 110 , an inverter unit 120 , a converter unit 130 , and a vehicle control device 140 .

[0014] The drive motor 110 outputs drive torque that is transmitted to the front wheels via the differential mechanism 150 and the front drive shaft. The drive motor 110 may be, for example, a double-stator axial gap motor. The drive of the drive motor 110 is controlled by a vehicle control device 140. The front drive shaft is provided with an electric steering device 160. The electric steering device 160 includes an electric motor (not shown) and a gear mechanism (not shown), and is controlled by the vehicle control device 140, which will be described later, to adjust the steering angle of the front wheels. The vehicle control device 140 controls the electric steering device 160 based on the steering angle of a steering wheel 170 operated by the driver.

[0015] The inverter unit 120 converts the DC power swept from the drive battery 410 into three-phase AC power and supplies it to a stator (not shown) of the drive motor 110. The inverter unit 120 also converts the three-phase AC power regenerated by the stator of the drive motor 110 into DC power and supplies it to the converter unit 130. The operation of the inverter unit 120 is controlled by the vehicle control device 140.

[0016] Converter unit 130 boosts the voltage of the electric power regenerated by drive motor 110 to the required charging voltage of drive battery 410 and supplies it to drive battery 410. Converter unit 130 may also boost or lower the output voltage of drive battery 410 and supply it to inverter unit 120. The operation of converter unit 130 is controlled by vehicle control device 140.

[0017] The vehicle control device 140 includes one or more ECUs (Electronic Control Units) that control the drive system 100 and the brake system 200 .

[0018] The brake system 200 applies braking force to each wheel. The brake system 200 may be, for example, a hydraulic brake system. In this case, the brake system 200 includes brake devices 210 provided on each wheel and a brake fluid pressure control device 220 that controls the hydraulic pressure supplied to each brake device 210. The hydraulic brake system 200 generates a predetermined braking force on each of the front, rear, left, and right drive wheels by controlling the hydraulic pressure supplied to each brake device 210. The brake system 200 is used in combination with a regenerative brake that uses the drive motor 110. The drive of the brake system 200 is controlled by the vehicle control device 140.

[0019] The vehicle state sensor 300 is connected to the vehicle control device 140 via a dedicated line or via communication means such as a CAN (Controller Area Network) or LIN (Local Inter Net). The vehicle state sensor 300 includes, for example, a steering angle sensor, an accelerator position sensor, a brake stroke sensor, a brake pressure sensor, or an engine rotation speed sensor, and detects the steering angle of the steering wheel or steered wheels, the accelerator opening, the brake operation amount, the engine rotation speed, etc. The vehicle state sensor 300 also includes, for example, a vehicle speed sensor, an acceleration sensor, or an angular velocity sensor, and detects the vehicle speed, longitudinal acceleration, lateral acceleration, yaw rate, etc. The vehicle state sensor 300 transmits a sensor signal including the detected information to the vehicle control device 140.

[0020] (Battery system) A battery system 400 according to a first embodiment of the present disclosure will be described in detail with reference to Fig. 2. The battery system 400 according to this embodiment includes a driving battery 410, a transport device 420, a temperature measurement device 430, and a control device 440.

[0021] (Drive battery) The drive battery 410 includes multiple battery cells C1 to C40 (hereinafter, collectively referred to as "battery cells C" unless a distinction is required). Each battery cell C is a secondary battery capable of charging and discharging, such as an all-solid-state battery. The battery pack 411 has a flat, approximately rectangular parallelepiped shape extending within a plane defined by a straight line along the vehicle length direction and a straight line along the vehicle width direction. Each battery cell C has a cylindrical or rectangular tube shape, for example, and is housed within the battery pack 411 with its central axis aligned along the vehicle height direction. The drive battery 410 is connected to the drive motor 110 via a converter unit 130 and an inverter unit 120, and stores the power supplied to the drive motor 110.

[0022] (Transportation device) The transport device 420 is configured to move each battery cell C at least while the vehicle 1000 is traveling. Referring also to FIG. 3 , the transport device 420 is, for example, a conveyor including a motor 421 connected to the auxiliary battery of the vehicle 1000, a gear 422 connected to the motor 421, a chain 423 meshing with the gear 422, and multiple studs 424 attached to the chain 423 so as to be rotatable relative to the chain 423. The multiple studs 424 form a transport path P that allows each battery cell C placed on each stud 424 to move within the battery pack 411. From the perspective of improving the volumetric energy density of the driving battery 410, the transport path P is preferably an endless transport path that meanders while folding back in a U-shape within the battery pack 411. Each stud 424 has, for example, a crescent shape and is made of a known or arbitrary insulating material. Known motors, gears, and chains can be used as the motor 421, gears, and chains, respectively. The driving of the transport device 420 is controlled by a control device 440 electrically connected to the transport device 420 .

[0023] 4, the battery system 400 includes a high-voltage contact wire 425H that electrically connects a high-voltage battery cell C1 (here, the positive electrode of the cell C1 faces the upper side of the battery pack 411) among the multiple battery cells C to the converter unit 130. The battery system 400 also includes a low-voltage contact wire 425L that electrically connects a low-voltage battery cell C40 among the multiple battery cells C to the converter unit 130. The high-voltage contact wire 425H is arranged along the movement trajectory of the high-voltage battery cell C1 and is fixed to the battery pack 411 by any method, for example, on the upper side inside the battery pack 411 (on the roof side of the vehicle 1000). On the other hand, the low-voltage contact wire 425L is arranged along the movement trajectory of the low-voltage battery cell C40 and is fixed to the battery pack 411 by any method, for example, on the upper side inside the battery pack 411 (on the roof side of the vehicle 1000).

[0024] 5, the positive electrode of the high-voltage side battery cell C1 is electrically connected to the high-voltage side contact wire 425H via a high-voltage side current collector 426H configured so as not to interfere with the movement of the battery cell C along the transport path P. Meanwhile, the negative electrode of the low-voltage side battery cell C40 is electrically connected to the low-voltage side contact wire 425L via a low-voltage side current collector 427L configured so as not to interfere with the movement of the battery cell C along the transport path P. Specifically, the high-voltage side current collector 426H is press-contacted to the underside of the high-voltage side contact wire 425H and includes a roller 427 that can roll along the high-voltage side contact wire 425H. The high-voltage side current collector 426H also includes a pole collector 428 that connects the roller 427 to the high-voltage side battery cell C1 and is connected to the high-voltage side battery cell C1 at a position offset a predetermined distance from the center axis of the high-voltage side battery cell C1. Meanwhile, the low-voltage side current collector 426L is equipped with a roller 427 that is pressed against the underside of the low-voltage side contact wire 425L and can roll along the low-voltage side contact wire 425L. The low-voltage side current collector 426L also includes a pole collector 428 that connects the roller 427 to the low-voltage side battery cell C40 and is connected to the low-voltage side battery cell C40 at a position offset a predetermined distance from the center axis of the low-voltage side battery cell C40. With this configuration, the roller 427 rolls along the contact wires 425H, 425L in accordance with the movement of each battery cell C, so charging and discharging of the driving battery 410 is not hindered. Therefore, each battery cell C can be moved not only when the vehicle 1000 is stopped, but also when the vehicle 1000 is moving. The offset can be set arbitrarily as long as the high-voltage side contact wire 425H and the low-voltage side contact wire 425L shown in FIG. 4 do not interfere with each other. Furthermore, if the number of battery cells C that can be set arbitrarily is an odd number, either the high-voltage side trolley wire 425H or the low-voltage side trolley wire 425L may be fixed to the battery pack 411 by any method on the lower side of the battery pack 411, rather than on the upper side of the battery pack 411.

[0025] 5, the battery system 400 includes a connection unit 412 that can connect multiple battery cells C to each other in series. The shape and material of the connection unit 412 are not particularly limited as long as the connection unit 412 is a known or arbitrary flexible member that does not impede the movement of each battery cell C along the transport path P by the transport device 420 and is a known or arbitrary conductive member. The multiple battery cells C may also be connected by a series-parallel connection that combines series connection and parallel connection. In this case, parallel groups formed by multiple parallel-connected battery cells C are connected to each other in series by the connection unit 412.

[0026] (temperature measuring device) 2, the temperature measuring device 430 is configured to be able to measure the temperatures of the multiple battery cells C. Specifically, the temperature measuring device 430 measures the temperature in a predetermined region of the driving battery 410. The temperature measuring device 430 is electrically connected to the control device 440, and transmits information indicating the measured temperature to the control device 440. Note that the predetermined region may include a first region of the multiple battery cells C whose temperature is equal to or higher than a threshold, and a second region of the multiple battery cells C whose temperature is lower than the threshold.

[0027] The temperature measuring device 430 may be an optical fiber sensor capable of measuring the temperature of each battery cell C in the battery pack 411 by utilizing backscattered light from an optical fiber in contact with the battery cell C. Specifically, the optical fiber sensor includes a light source 431, a light receiving unit 432, and a measuring unit 433. In this case, light emitted by the light source 431 passes through the optical fiber and reaches the measuring unit 433, where it is affected by temperature changes in the measuring unit 433. The light that reaches the measuring unit 433 then passes through the optical fiber again and reaches the light receiving unit 432. The change in light is then converted into a temperature change in the light receiving unit 432. Note that the optical fiber sensor may include a known or arbitrary winding force generating mechanism 434 using a spring or the like to prevent the optical fiber from becoming tangled on the transport path P due to each battery cell C moving within the battery pack 411. The temperature measuring device 430 is not limited to an optical fiber sensor as long as it can measure temperature changes of multiple battery cells C. For example, the temperature measuring device 430 may be a PTC thermistor that utilizes a change in resistance value associated with temperature changes. In this case, the PTC thermistor is disposed near the electrode of each battery cell C, and detects a change in the temperature of each battery cell C as a change in the resistance value of the PTC thermistor.

[0028] From the viewpoint of further suppressing deterioration of the battery system 400 and diagnosing faults in the battery cells C, it is preferable that the temperature measurement device 430 be arranged so that it can measure the temperatures of all the battery cells C in the battery pack 411, but the present disclosure is not limited to this. The temperature measurement device 430 may be arranged so that it can measure the temperatures of at least the battery cells C passing near the center of the battery pack 411. In addition, the temperature measurement device 430 may be arranged so that it can measure the temperatures of the battery cells C passing near the outer periphery of the battery pack 411.

[0029] (Control device) 6, the control device 440 determines whether or not to move the plurality of battery cells C based on the temperature in a predetermined area measured by the temperature measurement device 430. The control device 440 includes a control unit 441 and a storage unit 445.

[0030] The control unit 441 includes one or more processors, such as a CPU (Central Processing Unit) or an MPU (Micro Processing Unit). Part or all of the control unit 441 may be configured with updatable firmware or the like, or may be a program module or the like executed by instructions from the CPU or the like.

[0031] The storage unit 445 includes a memory communicatively connected to the processor. The storage unit 445 may include storage elements such as a random access memory (RAM) and a read only memory (ROM), or may include a storage device such as a CD-ROM or a storage device.

[0032] The control unit 441 includes an acquisition unit 442, a determination unit 443, and a drive control unit 444. Each of these units is a function realized by the execution of a computer program by a processor. However, some or all of these units may be configured using analog circuits.

[0033] Acquisition unit 442 acquires information relating to the usage state of driving battery 410. Specifically, acquisition unit 442 acquires information indicating the temperature in a predetermined region of driving battery 410 measured by temperature measurement device 430 from temperature measurement device 430. Acquisition unit 442 also acquires information indicating the detection results of vehicle condition sensor 300 from vehicle condition sensor 300.

[0034] The determination unit 443 determines whether or not to move the plurality of battery cells C based on the usage state of the driving battery 410. Specifically, the determination unit 443 determines whether or not to move the plurality of battery cells C based on the temperature in a predetermined area acquired by the acquisition unit 442. Details will be described later.

[0035] The drive control unit 444 generates control information for controlling the transport device 420 based on the result of the determination by the determination unit 443. The drive control unit 444 also transmits the generated control information to the transport device 420. Note that the control information may include the rotation direction, rotation time, rotation speed, etc. of the motor 421 provided in the transport device 420.

[0036] The technical significance of using the transport device 420 to move each battery cell C will now be described in detail with reference to Figures 7 to 10. Figure 7 shows the time change in current simulating the charging and discharging of the drive battery 410 while the vehicle 1000 is running. Figure 8 shows the temperature changes of battery cell C30, which shows the highest temperature, and battery cell C10, which shows the lowest temperature, when the drive battery 410 is repeatedly charged and discharged using the current shown in Figure 7 and reaches a steady state. Figure 9 shows the temperature distribution of each battery cell C in the steady state shown in Figure 8. In this description, it is assumed that battery cells C22 to C31 and C33 to C40 are located near the center of the battery pack 411, and battery cells C1 to C20 are located near the periphery of the battery pack 411. 9, the battery cells C22 to C31 and C33 to C40 located near the center of the battery pack 411 are less likely to dissipate heat than the battery cells C1 to C20 located near the periphery of the battery pack 411, and are therefore more likely to reach high temperatures if left to natural cooling. Therefore, if the battery cells C22 to C31 and C33 to C40 located near the center of the battery pack 411 are used as is, they will deteriorate faster than the battery cells C1 to C20 located near the periphery of the battery pack 411. Therefore, the transport device 420 moves (hereinafter also referred to as "rotates") the battery cells C22 to C31 and C33 to C40 located near the center of the battery pack 411 to near the periphery of the battery pack 411, as shown in FIG. 10. As a result of this movement, the battery cells C22 to C31 and C33 to C40 are located near the periphery of the battery pack 411, and therefore heat is dissipated by natural cooling, and their temperatures decrease without the use of a separate cooling mechanism. That is, not only when the vehicle 1000 is stopped, but also when the vehicle 1000 is moving, the high-temperature battery cells C22 to C31 and C33 to C40 and the low-temperature battery cells C1 to C20 can be alternately replaced. As a result, deterioration of the battery system 400 can be suppressed.Furthermore, when an all-solid-state battery is adopted as the drive battery 410, the volumetric energy density can be improved by, for example, a cell-to-pack configuration, and by taking advantage of the wide operating temperature characteristics of the all-solid-state battery, a compact (small and lightweight) battery system 400 can be constructed that is primarily based on natural air cooling.

[0037] (Example of control device operation) An example of the operation of the control device 440 will now be described in detail with reference to FIG.

[0038] In step S10, the determination unit 443 of the control device 440 determines whether the vehicle 1000 has started to move. Specifically, the determination unit 443 of the control device 440 determines whether the vehicle 1000 is moving or stopped based on the detection result of the vehicle state sensor 300, such as a vehicle speed sensor. If it is determined that the vehicle 1000 has started to move (step S10: Yes), the process proceeds to step S11. On the other hand, if it is not determined that the vehicle 1000 has started to move (step S10: No), the process repeats step S10 until it is determined that the vehicle 1000 has started to move.

[0039] In step S11, acquisition section 442 of control device 440 acquires information indicating the temperature in a predetermined region of driving battery 410 measured by temperature measurement device 430. The process then proceeds to step S12.

[0040] The predetermined region includes a first region among the plurality of battery cells C whose temperature is equal to or higher than a threshold value and a second region among the plurality of battery cells C whose temperature is lower than the threshold value. Specifically, the first region may be near the center of the battery pack 411, and the second region may be near the outer periphery of the battery pack 411. More specifically, when the battery pack 411 has a flattened, approximately rectangular parallelepiped shape extending in a plane defined by a straight line along the vehicle length direction and a straight line along the vehicle width direction, the first region may be a region within a predetermined range from the center of the approximately rectangular parallelepiped. Furthermore, the second region may be a region within a predetermined range from a side surface connected to the bottom surface of the approximately rectangular parallelepiped. Alternatively, the second region may be a region of the transport path P of the transport device 420 that is located closest to the side surface connected to the bottom surface of the battery pack 411, and the first region may be a region of the transport path P of the transport device 420 that is located at a position other than the second region.

[0041] In step S12, the determination unit 443 of the control device 440 determines whether or not to move the plurality of battery cells C based on the temperature in the predetermined region acquired in step S11. Specifically, the determination unit 443 of the control device 440 determines whether or not to move the plurality of battery cells C based on the temperature difference between a first temperature in a first region of the plurality of battery cells C whose temperature is equal to or higher than a threshold and a second temperature in a second region of the plurality of battery cells C whose temperature is lower than the threshold. The processing of step S12 will be described in detail below with reference to FIG. 12 as well.

[0042] 12 indicates the temperature change of the plurality of battery cells C that were located near the center of the battery pack 411 before time t1. On the other hand, the solid line in FIG. 12 indicates the temperature change of the plurality of battery cells C that were located near the periphery of the battery pack 411 before time t1. In step S12, the determination unit 443 of the control device 440 determines to move the plurality of battery cells C at time t1 when the temperature difference between the battery cell C that exhibits the highest temperature among the plurality of battery cells located near the center of the battery pack 411 and the battery cell C that exhibits the lowest temperature among the plurality of battery cells located near the periphery of the battery pack 411 reaches a threshold value T0. As will be described in detail later, by repeating the series of processes from step S11 to S13 (i.e., by executing rotation at times t1, t2, and t3), the temperature variation of the plurality of battery cells C in the battery pack 411 falls within the threshold value T0, as shown in FIG. The threshold value T0 is the average temperature T of the driving battery 410 when the temperature of the driving battery 410 has converged. ave0 This can be set appropriately taking into consideration the required lifespan of the driving battery 410, etc.

[0043] 11, if it is determined in step S12 that multiple battery cells C are to be moved (step S12: Yes), the process proceeds to step S13. On the other hand, if it is not determined that multiple battery cells C are to be moved (step S12: No), the process returns to step S11.

[0044] In step S13, the drive control unit 444 of the control device 440 generates control information for controlling the transport device 420. Then, the drive control unit 444 of the control device 440 transmits the generated control information to the transport device 420. As a result, the transport device 420 moves the multiple battery cells C based on the control information received from the control device 440. Specifically, the multiple battery cells C1 to C40 located near the center of the battery pack 411 in FIG. 2 move to the positions shown in FIG. 10. That is, the multiple battery cells C22 to C31 and C33 to C40 located near the center of the battery pack 411 in FIG. 2 move counterclockwise in a top view of the battery pack 411, thereby moving to the vicinity of the outer periphery of the battery pack 411 as shown in FIG. 10. Then, the process proceeds to step S14.

[0045] Here, the control information can include the rotation direction, rotation time, rotation speed, etc. of the motor 421 of the transport device 420. The rotation direction of the motor 421 is appropriately determined by the drive control unit 444 of the control device 440 so that the movement of the battery cells C alternates between counterclockwise and clockwise when viewed from above the battery pack 411, with each rotation performed by the series of operations in steps S11 to S13. With reference to Fig. 4, the rotation speed and rotation time of the motor 421 are appropriately determined according to the movement distance of the battery cell C1 from one end a to the other end b of the high-voltage contact wire 425H and the movement distance of the battery cell C40 from one end d to the other end c of the low-voltage contact wire 425L, for example, when each battery cell C moves from the position shown in Fig. 2 to the position shown in Fig. 10.

[0046] End points a and b of the high-voltage side contact wire 425H are appropriately positioned so that, with one rotation, a battery cell C located near the center of the battery pack 411 can be moved closer to the periphery, and a battery cell C located near the periphery of the battery pack 411 can be moved closer to the center. Similarly, end points c and d of the low-voltage side contact wire 425L are appropriately positioned so that, with one rotation, a battery cell C located near the center of the battery pack 411 can be moved closer to the periphery, and a battery cell C located near the periphery of the battery pack 411 can be moved closer to the center. Note that the high-voltage side contact wire 425H and the low-voltage side contact wire 425L may each be arranged around the entire circumference of the transport path P. In this case, the moving direction of the battery cell C does not need to be reversed with each rotation, and may be either clockwise or counterclockwise when viewed from above the battery pack 411.

[0047] In step S14, the determination unit 443 of the control device 440 determines whether or not to end the series of processes of steps S11 to S13. Specifically, when the determination unit 443 of the control device 440 determines that the vehicle 1000 is in a stopped state based on the detection result of the vehicle state sensor 300, such as a vehicle speed sensor, the determination unit 443 determines to end the series of processes of steps S11 to S13. When it is determined to end the series of processes of steps S11 to S13 (step S14: Yes), the process ends. On the other hand, when it is not determined to end the series of processes of steps S11 to S13 (step S14: No), the process returns to step S11.

[0048] (effect) As described above, the battery system 400 according to this embodiment has the following features: a driving battery 410 for the vehicle 1000 including a plurality of battery cells C1 to C40; a transport device 420 capable of moving the plurality of battery cells C1 to C40 at least while the vehicle 1000 is traveling; a control device 440 that determines whether or not to move the battery cells C1 to C40 based on the usage state of the driving battery 410; Here, the usage state of the driving battery 410 is the temperature in a predetermined region of the driving battery 410 measured by a temperature measurement device 430 capable of measuring the temperatures of multiple battery cells C1 to C40. With this configuration, even while the vehicle 1000 is running, the battery cells C on the high temperature side and the battery cells C on the low temperature side are alternately switched, thereby suppressing the temperature rise of the battery cells C through natural cooling. As a result, deterioration of the battery system 400 can be suppressed, and the battery system 400 can be made more compact.

[0049] The predetermined area in step S11 may be only the vicinity of the center of the battery pack 411. In this case, in step S12, the determination unit 443 of the control device 440 determines whether to move the multiple battery cells C1 to C40 based on the temperature in the vicinity of the center of the battery pack 411. Specifically, when the temperature of, for example, a battery cell showing the highest temperature among the multiple battery cells C located in the vicinity of the center of the battery pack 411 is equal to or higher than a threshold value, the determination unit 443 of the control device 440 determines to move the multiple battery cells C1 to C40.

[0050] <Second embodiment> (Battery system) A battery system 500 according to a second embodiment of the present disclosure will be described with reference to Fig. 13. Battery system 500 according to this embodiment includes a driving battery 410, a transport device 420, a current measuring device 450, and a control device 440. Note that driving battery 410 and transport device 420 can be configured in the same manner as in the first embodiment.

[0051] (Current measuring device) Current measuring device 450 is a current sensor capable of measuring the current of drive battery 410. Note that various configurations of current sensors known in electric vehicles or hybrid electric vehicles can be applied to the current sensor. Current measuring device 450 is electrically connected to control device 440 and transmits information indicating the measured current to control device 440. Note that the current includes a charging current when vehicle 1000 is regenerating and a discharging current when vehicle 1000 is accelerating.

[0052] (Control device) The control device 440 includes a control unit 441 and a storage unit 445, similar to the first embodiment. The control unit 441 includes an acquisition unit 442, a determination unit 443, and a drive control unit 444. Below, the functions of each unit of the control unit 441 that differ from those of the first embodiment will be described.

[0053] Acquisition unit 442 acquires information indicating the usage state of driving battery 410. Specifically, acquisition unit 442 acquires information indicating the integrated value of the charging current and discharging current of driving battery 410 measured by current measurement device 450. Note that this integrated value is initially set to 0 A and is initialized to 0 A at each rotation.

[0054] The determination unit 443 determines whether or not to move the multiple battery cells C based on the usage state of the driving battery 410. Specifically, the determination unit 443 determines whether or not to move the multiple battery cells C based on the integrated values of the charging current and discharging current of the driving battery 410 acquired by the acquisition unit 442.

[0055] The drive control unit 444 can be configured in the same manner as in the first embodiment.

[0056] (Example of control device operation) An example of the operation of control device 440 in the second embodiment will be described in detail with reference to FIG.

[0057] In step S20, the determination unit 443 of the control device 440 determines whether or not the vehicle 1000 has started moving, in the same manner as in the first embodiment. If it is determined that the vehicle 1000 has started moving (step S20: Yes), the process proceeds to step S21. On the other hand, if it is not determined that the vehicle 1000 has started moving (step S20: No), the process repeats step S20 until it is determined that the vehicle 1000 has started moving.

[0058] In step S21, acquisition section 442 of control device 440 acquires the integrated values of the charging current and discharging current of driving battery 410 measured by current measurement device 450. After that, the process proceeds to step S22.

[0059] In step S22, the determination unit 443 of the control device 440 determines whether or not to move multiple battery cells C based on the integrated values of the charge and discharge currents of the driving battery 410 acquired in step S21. Specifically, the determination unit 443 of the control device 440 determines to move multiple battery cells C if the integrated value of the charge and discharge currents of the driving battery 410 is equal to or greater than a threshold. On the other hand, the determination unit 443 of the control device 440 does not determine to move multiple battery cells C if the integrated value of the charge and discharge currents of the driving battery 410 is not equal to or greater than a threshold. Note that the temperature of the driving battery 410 increases as the charging and discharging time of the driving battery 410 increases. Therefore, the threshold can be set in advance based on the relationship between charging and discharging time and temperature changes of the battery cells C shown in FIG. 8. If it is determined to move multiple battery cells C (step S22: Yes), the process proceeds to step S23. On the other hand, if it is not determined that multiple battery cells C are to be moved (step S22: No), the process returns to step S21.

[0060] In step S23, the drive control unit 444 of the control device 440 generates control information for controlling the transport device 420. Then, the drive control unit 444 of the control device 440 transmits the generated control information to the transport device 420. As a result, the transport device 420 moves the multiple battery cells C based on the control information received from the control device 440. The details are the same as in the first embodiment. Thereafter, the process proceeds to step S24.

[0061] In step S24, the determination unit 443 of the control device 440 determines whether or not to end the series of processes from steps S21 to S23. Details are the same as in the first embodiment. If it is determined that the series of processes from steps S21 to S23 should be ended (step S24: Yes), the process ends. On the other hand, if it is not determined that the series of processes from steps S21 to S23 should be ended (step S24: No), the process returns to step S21.

[0062] (effect) As described above, the battery system 400 according to this embodiment has the following features: a driving battery 410 for the vehicle 1000 including a plurality of battery cells C1 to C40; a transport device 420 capable of moving the plurality of battery cells C1 to C40 at least while the vehicle 1000 is traveling; a control device 440 that determines whether or not to move the battery cells C1 to C40 based on the usage state of the driving battery 410; Here, the usage state of the driving battery 410 is the integrated value of the charging current and discharging current of the driving battery 410 measured by the current measuring device 450. With this configuration, by using a current sensor, for example, that is used in a known electric vehicle or hybrid electric vehicle, it is possible to suppress deterioration of the battery system 400 even while the vehicle 1000 is traveling, and it is also possible to make the battery system 400 more compact.

[0063] Note that this embodiment is not limited to the integrated value used in steps S21 and S22, and an index indicating the charge / discharge status, such as the integrated number of times the driving battery 410 has been charged / discharged, may also be used.

[0064] Although preferred embodiments of the present disclosure have been described in detail above with reference to the accompanying drawings, the present disclosure is not limited to such examples. It is clear that a person skilled in the art to which the present disclosure pertains can conceive of various modifications or alterations within the scope of the technical ideas described in the claims, and it is understood that these also naturally fall within the technical scope of the present disclosure. For example, the functions included in each component or step can be rearranged so as not to be logically inconsistent, and multiple components or steps can be combined or divided into one.

[0065] (First Modification) 15, battery system 600 according to the first modification may further include air filter 460 that takes in air outside vehicle 1000 into battery pack 411, circulates the taken-in air within battery pack 411, and then discharges the air to the outside of battery pack 411. For example, when the average temperature T ave0 When it is necessary to suppress the rise of the temperature of the driving battery 410, it is preferable to partially air-cool the vicinity of the periphery of the battery pack 411 by using the air filter 460 in addition to moving the plurality of battery cells C. Since natural air cooling is possible by moving the plurality of battery cells C, it is sufficient if the air flow by the air filter 460 is formed only in a part (near the periphery) of the battery pack 411. According to the first modification, even during quick charging or when the outside air temperature is high, for example, it is possible to suppress the temperature variation of the plurality of battery cells C to within the threshold value T0, and also to prevent the average temperature T of the driving battery 410 from increasing. ave0 The increase in the temperature can be suppressed.

[0066] (Second Modification) Referring to FIG. 16, a battery system 700 according to a second modified example includes a drive battery 710, a transport device 720, and a control device 440 configured similarly to the first or second embodiment. Below, only differences from the first or second embodiment will be described. FIG. 16 shows a cross section of the drive battery 710, for example, along the vehicle height direction. The battery pack 711 of the drive battery 710 has a flat, approximately rectangular parallelepiped shape extending within a plane defined by lines along the vehicle length direction and lines along the vehicle width direction. Furthermore, the drive battery 710 is provided with multiple battery modules M arranged along the vehicle height direction (two rows in the example shown in FIG. 17), each of which includes one or more battery cells C extending within a plane defined by lines along the vehicle length direction and lines along the vehicle width direction, as shown in FIG. 17. Each battery module M has a cylindrical or rectangular tubular shape with a central axis along the vehicle length direction or the vehicle width direction, and is housed within the battery pack 711 insulated except for the electrodes. The battery modules M are connected in series by connection parts 712 configured in the same manner as in the first or second embodiment. The battery modules M are fixed by fixing members 713 such as bands that have flexibility and can separate the battery modules M by a predetermined distance. The fixing members 713 are connected by a known locking mechanism 714.

[0067] The transport device 720 is configured to transport multiple battery modules M, each including one or more battery cells C, at least while the vehicle 1000 is traveling. Specifically, the transport device 720 includes a motor 721, a gear 722 connected to the motor 721, and a conveyor belt 723 that meshes with the gear 722. The motor 721 and the gear 722 may be publicly known motors and gears, respectively. The conveyor belt 723 is made of an insulating material such as resin or rubber, and preferably has a mesh shape to ensure a sufficient heat dissipation area for the battery modules M. Rails are appropriately attached to the conveyor belt 723 to prevent the battery modules M from shifting. The number and width of the conveyor belt 723 can be appropriately set to a degree that ensures reliable movement of each battery module M. Depending on the weight of the battery modules M, support rods 724 fixed to the battery packs 711 or bearings may be appropriately provided.

[0068] The control device 440 determines whether or not to move the battery module M based on the usage state of the driving battery 710, in the same manner as in the first or second embodiment.

[0069] The second modified example has been described above, but whether to adopt the battery system 400 according to the first or second embodiment or the battery system 700 according to the second modified example can be determined appropriately taking into consideration the size of the interior space of the vehicle 1000, etc. For example, although the battery system 700 has a larger thickness along the vehicle height direction, it has a larger number of battery modules M located near the outer periphery of the battery pack 711 (toward the bottom of the vehicle 1000), and therefore has good natural cooling efficiency. Therefore, when a certain amount of space along the vehicle height direction for accommodating the battery system 700 can be secured and it is necessary to improve the cooling efficiency of the traction battery 710, it is preferable to adopt the battery system 700 according to the second modified example.

[0070] (Third Modification) In the first or second embodiment, the movement of the plurality of battery cells C is not limited to when the vehicle 1000 is traveling, and may be performed while the vehicle 1000 is stopped. For example, the movement of the plurality of battery cells C may be performed while the vehicle 1000 is stopped in order to reduce variations in the temperature distribution of the plurality of battery cells C when the vehicle 1000 is being charged. Specifically, the determination unit 443 of the control device 440 determines whether charging of the vehicle 1000 has started based on, for example, a voltage value between the terminals of the driving battery 410 measured by a known voltage sensor (not shown) provided in the vehicle 1000. The determination unit 443 of the control device 440 then determines to start the processing of steps S11 to S13 in the first embodiment or the processing of steps S21 to S23 in the second embodiment. When the determination unit 443 of the control device 440 determines that charging of the vehicle 1000 has ended based on, for example, the voltage value between the terminals of the driving battery 410, the determination unit 443 determines to end these processes.

[0071] (Fourth Modification) The vehicle control device 140 in the above-described embodiment or modification may also have part or all of the configuration and operation of the control device 440 in the above-described embodiment or modification.

[0072] (Fifth Modification) It is also possible to store a program describing the processing content for realizing each function of the control device 440 according to the above-described embodiment or modification in a computer memory, and to have a processor read and execute the program. Therefore, the present disclosure can also be realized as a program executable by a processor, or a non-transitory tangible recording medium that stores the program. [Explanation of symbols]

[0073] 1000 vehicles 400,500,600,700 battery system 410,710 Drive battery 420,720 Conveyor equipment 430 Temperature measuring device 440 Control Device 450 Current measuring device

Claims

1. a vehicle drive battery including a plurality of battery cells; a transport device that can move the plurality of battery cells at least while the vehicle is traveling; a control device that determines whether to move the plurality of battery cells based on the usage state of the drive battery; Equipped with Battery system.

2. a temperature measuring device capable of measuring the temperatures of the plurality of battery cells; the usage state includes a temperature in a predetermined region of the driving battery measured by the temperature measurement device; the control device determines whether to move the plurality of battery cells based on the temperature in the predetermined area. The battery system according to claim 1 .

3. the predetermined region includes a first region among the plurality of battery cells in which the temperature is equal to or higher than a threshold, and a second region among the plurality of battery cells in which the temperature is lower than the threshold, the control device determines whether to move the plurality of battery cells based on a temperature difference between a first temperature in the first region and a second temperature in the second region. The battery system according to claim 2 .

4. a high-voltage contact wire that is arranged along a movement locus of the plurality of battery cells and electrically connects a high-voltage battery cell among the plurality of battery cells to a converter unit provided on the vehicle; a low-voltage contact wire that is arranged along a movement locus of the plurality of battery cells and electrically connects a low-voltage battery cell among the plurality of battery cells to the converter unit; Further provided with The battery system according to claim 1 .

5. further comprising a connection portion that can connect the plurality of battery cells to each other in series, The battery system according to claim 1 .

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