Control method and control device for battery pressurizing mechanism and vehicle

Abstract

In the present invention, an appropriate pressurizing force is applied in accordance with changes in battery cell thickness while reducing the motor load on a drive mechanism. A pressurizing mechanism (30) comprises: a pair of pressurizing plates (31, 32) disposed facing a battery module (10); an elastic pressing member (50) interposed between the pair of pressurizing plates (31, 32) to apply pressurizing force to the battery module (10); a linear motion mechanism (40) capable of expanding or contracting the facing distance (W) between the pair of pressurizing plates (31, 32); and a drive mechanism (60) that drives the linear motion mechanism (40). A control device (80) comprises a measurement unit (81) and a control unit (82). When the rate of change of the facing distance (W) measured by the measurement unit (81) is equal to or greater than a prescribed rate, the control unit (82) drives the drive mechanism (60) to pressurize the battery module (10) together with elastic pressure exerted by the elastic pressing member (50), whereas when the rate of change is less than the prescribed rate, the drive mechanism (60) is not driven and the battery module (10) is pressurized using only the elastic pressing member (50).

Description

Battery pressurizing mechanism control method and control device, and vehicle

[0001] The present invention relates to a control technology for a battery pressurizing mechanism that actively pressurizes a lithium deposition-type all-solid-state battery.

[0002] In this type of all-solid-state battery, the thickness of the battery cell changes depending on the charge and discharge. Therefore, to ensure stable battery performance, a battery pressure mechanism that actively applies pressure to the all-solid-state battery is required. The technology described in Patent Document 1 controls the energy stored in the spring by focusing on reducing the motor load.

[0003] WO2020 / 044791 A1

[0004] However, the technology described in the document simply controls the energy stored in the spring, and if it is not possible to properly control the pressure in accordance with the thickness of the battery cell, which expands and contracts in response to charging and discharging, there is a problem that the pressure will be too strong or too weak, causing the battery system to stop functioning.

[0005] Therefore, an object of the present invention is to provide a control method and control device for a battery pressurizing mechanism, and a vehicle, which can apply an appropriate pressure in accordance with changes in the thickness of the battery cells while reducing the motor load on the drive mechanism.

[0006] In order to solve the above-mentioned problems, a control method for a battery pressurizing mechanism according to one aspect of the present invention is a method for controlling a pressurizing mechanism that pressurizes an all-solid-state battery in its expansion / contraction direction, the pressurizing mechanism including a pair of pressurizing plates that are arranged opposite the all-solid-state battery in the expansion / contraction direction, a resilient pressure member that is interposed between the pair of pressurizing plates and applies a pressurizing force to the all-solid-state battery, a linear motion mechanism that can expand and contract the opposing distance between the pair of pressurizing plates, and a drive mechanism that drives the linear motion mechanism, and when pressurizing the all-solid-state battery, the opposing distance between the pair of pressurizing plates is measured at any time, and in accordance with a rate of change of the measured opposing distance, if the rate of change is equal to or greater than a predetermined value, the drive mechanism is driven to apply pressurization together with resilient pressure by the resilient pressure member, and if the rate of change is less than the predetermined value, the drive mechanism is not driven and pressurization is performed only by the resilient pressure member.

[0007] Furthermore, in order to solve the above-mentioned problems, a control device for a battery pressurizing mechanism according to one aspect of the present invention is a control device used in a pressurizing mechanism that pressurizes an all-solid-state battery in its expansion / contraction direction, the pressurizing mechanism comprising: a pair of pressurizing plates arranged opposite the all-solid-state battery in the expansion / contraction direction; a resilient pressure member interposed between the pair of pressurizing plates and applying a pressurizing force to the all-solid-state battery; a linear motion mechanism that can expand and contract the opposing distance between the pair of pressurizing plates; and a drive mechanism that drives the linear motion mechanism, the control device comprising: a measurement unit that constantly measures the opposing distance between the pair of pressurizing plates; and a control unit that controls the drive mechanism, the control unit executes a pressurization control process that controls pressurization of the all-solid-state battery, and, in response to a rate of change of the measured opposing distance, if the rate of change is equal to or greater than a predetermined value, executes a linear motion pressurization control that drives the drive mechanism to apply pressurization together with resilient pressure by the resilient pressure member, and if the rate of change is less than the predetermined value, executes a resilient pressure pressurization control that applies pressurization only by the resilient pressure member without driving the drive mechanism.

[0008] In order to solve the above problems, a vehicle according to one aspect of the present invention is a vehicle equipped with an all-solid-state battery, and includes a pressurizing mechanism that pressurizes the all-solid-state battery in its expansion / contraction direction, and a control device that controls the pressurizing mechanism, and the control device includes the battery pressurizing mechanism control device according to one aspect of the present invention.

[0009] According to the present invention, it is possible to apply an appropriate pressure in accordance with changes in the thickness of the battery cell while reducing the motor load of the drive mechanism.

[0010] 5 is a schematic explanatory diagram of a first embodiment of a battery pack including a pressure mechanism according to an aspect of the present invention. FIG. 1 is an explanatory diagram showing the pressure mechanism of FIG. 1. FIG. 2 is an explanatory diagram of a resilient pressure member included in the pressure mechanism of FIG. 1, where FIG. 2(a) is a schematic plan view of FIG. 2, and FIG. 2(b) is a diagram illustrating an image of the function of the resilient pressure member to uniformly distribute the surface pressure. FIG. 5 is a graph illustrating an image of the pressure mechanism of FIG. 1 controlling the surface pressure on the battery module (all-solid-state battery) within a desired range. FIG. 6 is a flowchart of a pressure control process executed by a control unit of a control device that controls the pressure mechanism of FIG. 1. FIG. 7 is a flowchart of direct pressure control in the pressure control process of FIG. 5. FIG. 7 is a graph (a) and (b) illustrating the operation and effects of the pressure control process when a required output exceeds the output by resilient pressure control. FIG. 8 is a graph (a) and (b) illustrating the operation and effects of the pressure control process when an all-solid-state battery is being charged. FIG. 9 is a graph (a) and (b) illustrating the operation and effects of the pressure control process when a vehicle is stopped. FIG. 10 is a graph (a) and (b) illustrating the operation and effects of the pressure control process when a vehicle is in normal operation.

[0011] An embodiment of the present invention will be described below with reference to the drawings as appropriate. In this embodiment, an example will be described in which an all-solid-state battery equipped with a pressurizing mechanism according to one aspect of the present invention is mounted on a vehicle. Note that the drawings are schematic. Therefore, it should be noted that the relationship between thickness and planar dimensions, ratios, etc. differ from the actual ones, and the drawings also include portions in which the relationship between dimensions and ratios differ from one another. Furthermore, the embodiments shown below exemplify devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the materials, shapes, structures, arrangements, etc. of component parts to the following embodiments.

[0012] [Configuration of Battery Pack] First, an embodiment of a battery pack including a battery pressurizing mechanism that actively pressurizes a lithium deposition-type all-solid-state battery will be described. As shown in Fig. 1, the battery pack 1 of this embodiment includes one battery module 10 as an all-solid-state battery (set). The battery module 10 is configured by stacking a plurality of battery cells 12 in the expansion / contraction direction M.

[0013] Each battery cell 12 constituting the battery module 10 is a Li-precipitation type all-solid-state battery, and expands and contracts in the stacking direction of the battery cells 12 in response to charging and discharging. The Li-precipitation type all-solid-state battery has a much larger amount of cell expansion in the stacking direction than a conventional liquid Lib type battery.

[0014] The battery pack 1 of this embodiment includes a storage case 20 that houses the battery module 10 therein, and a pressure mechanism 30 that applies pressure to the battery module 10 in the expansion / contraction direction M of the multiple battery cells 12. The storage case 20 is, for example, a rectangular parallelepiped housing made of metal (for example, aluminum alloy), and stores the multiple battery cells 12 in a stacked position along the long side of the storage case 20.

[0015] The pressure mechanism 30 of this embodiment is disposed between one end face (the lower side in the figure) of the battery module 10 and the short side of the housing case 20 that faces that end face. As a result, in the battery module 10 inside the housing case 20, the multiple battery cells 12 are maintained in a stacked arrangement state with the cells 12 constantly being pressed upward in the expansion / contraction direction M by the pressure mechanism 30 at the bottom of the figure.

[0016] [Configuration of Pressuring Mechanism] Next, a more detailed description will be given of the pressing mechanism 30. As shown in Fig. 2 , which is an enlarged view of a main portion, the pressing mechanism 30 of this embodiment includes a pair of pressing plates 31, 32 arranged to face the battery module 10 in the expansion / contraction direction M, a resilient pressure member 50 interposed between the pair of pressing plates 31, 32, a linear motion mechanism 40 that changes the facing distance between the pair of pressing plates 31, 32 along the expansion / contraction direction M, and a drive mechanism 60 that drives the linear motion mechanism 40.

[0017] In this embodiment, the pair of pressure plates 31, 32 includes a cell-side pressure plate 32 that contacts the battery module 10, and a drive-side pressure plate 31 that is linearly actuated by a linear-acting mechanism 40. The cell-side pressure plate 32 contacts battery cells 12 located at opposite ends in the extension / contraction direction M, and is capable of pressing the entire battery module 10. The drive-side pressure plate 31 is configured to be able to advance and retreat in the extension / contraction direction M in response to the drive of the drive mechanism 60, as will be described later.

[0018] The drive mechanism 60 is disposed on the opposite side of the elastic pressure member 50 with respect to the drive-side pressure plate 31. In the drive mechanism 60 of this embodiment, a motor 63 is fixed to the inner wall surface of the housing case 20 via a drive unit holder 70 (see FIG. 1). A worm gear is used for the drive mechanism 60. The worm gear is a rotation mechanism that combines a worm (screw gear) 61 and a worm wheel (helical teeth) 62 that meshes with the worm. Note that a hypoid gear can be used instead of the worm gear.

[0019] The worm 61 is provided coaxially on the tip of the output shaft of the motor 63, and when the worm 61 is rotated by the drive of the motor 63, the teeth of the worm wheel 62 are advanced in the circumferential direction, thereby rotating the worm wheel 62. In this embodiment, the lead angle of the worm 61 is made small and set to be self-locking, preventing transmission of rotation from the worm wheel 62 side to the worm 61 side.

[0020] In this embodiment, a ball screw using, for example, a feed screw is employed as the linear motion mechanism 40. The ball screw includes a nut 42 having a helical thread groove formed on its inner peripheral surface, a screw shaft 41 having a helical thread groove formed on its outer peripheral surface that faces the thread groove of the nut 42, and a large number of balls (not shown) interposed in ball rolling paths formed between the facing thread grooves of the screw shaft 41 and the nut 42.

[0021] The numerous balls are housed within a ball circulation mechanism (not shown) that includes a ball circulation path and the like so that they can circulate infinitely. The member screw shaft 41 penetrates the drive-side pressure plate 31 in the expansion / contraction direction M, and the flange end face of the nut 42 is fixed to the drive-side pressure plate 31. Furthermore, the nut 42 is threadedly engaged with the screw shaft 41 via numerous balls, and is attached so that the drive-side pressure plate 31 can be linearly moved in the expansion / contraction direction M in response to the rotation of the screw shaft 41. Note that the linear motion mechanism 40 is not limited to a ball screw, and a feed screw without balls may be used, or another linear motion mechanism may be adopted.

[0022] The elastic pressure member 50 of this embodiment is configured to have a plurality of springs 51 interposed in parallel between the cell-side pressure plate 32 and the drive-side pressure plate 31 so as to be able to distribute the pressing force on the battery module 10. As the elastic pressure member 50, various types of elastic bodies using springs, rubber, etc. can be arranged between the pair of pressure plates 31, 32.

[0023] The springs 51 in this embodiment are cylindrical coil springs. As shown in FIG. 3A, the multiple springs 51 consist of eight cylindrical coil springs arranged in parallel (four longitudinally in two vertical rows, for a total of eight springs) in a plan view. In particular, in this embodiment, the cylindrical center of each cylindrical coil spring (the position indicated by the "x" symbol 51c in the figure) is located inside the projection of the electrode portion of the battery cell 12 (the shaded area indicated by the symbol 12m in the figure). This reduces stress on the edge of the battery cell 12 electrode when pressure is applied. It also prevents or suppresses damage such as cracks at the edge of the electrode portion due to pressure. The two-dot chain line (32) in FIG. 3B illustrates the bending of the cell-side pressure plate due to uneven application of pressure F when the elastic pressure member 50 is positioned in a way that prevents the pressure from being distributed.

[0024] Next, the relationship between the control surface pressure and the lower limit surface pressure, which is specific to the pressure mechanism 30 of this embodiment, will be described. As described above, in a Li deposition-type all-solid-state battery such as the battery cell 12 of this embodiment, the amount of cell expansion in the stacking direction is significantly greater than in conventional liquid Lib-type secondary batteries due to the use of Li metal in the negative electrode. Therefore, in order to ensure that the pressure applied by the pressure mechanism 30 follows the expansion and contraction of the battery module 10 within the appropriate surface pressure range, it is necessary to make the volume of the feed screw larger than in the past. On the other hand, since increasing the volume of the feed screw of the linear motion mechanism 40 reduces the cell capacity, it is desirable to configure the feed screw compactly.

[0025] 1 and 2 , the pressure mechanism 30 of this embodiment employs a pressure structure that includes a pair of opposing pressure plates 31, 32, a resilient pressure member 50, a linear motion mechanism 40, and a drive mechanism 60 that drives these, with the resilient pressure member 50 disposed between the pair of pressure plates 31, 32. According to the pressure mechanism 30 of this embodiment, the linear motion mechanism 40 and the resilient pressure member 50 are not independent but are integrally disposed on the same side in the stacking direction of the battery cells 12. This allows the volume occupied by the pressure mechanism 30 in the expansion / contraction direction M to be compact, enabling more battery cells 12 to be placed in the space required for the springs 51. Furthermore, according to the pressure mechanism 30 of this embodiment, by disposing the resilient pressure member 50 between the pair of pressure plates 31, 32, it is possible to absorb any collapse or non-uniformity of the cell-side pressure plate 32 when absorbing displacement of the battery cells 12 in the expansion / contraction direction M, thereby making the surface pressure distribution more uniform.

[0026] In particular, in the pressure mechanism 30 of this embodiment, the linear motion direction of the linear motion mechanism 40 and the deflection direction of the spring of the elastic pressure member 50 are arranged in series in the expansion / contraction direction M. This makes it easy to control the applied pressure so that it follows the appropriate range of surface pressure with the pressure mechanism 30 of this embodiment. That is, in this embodiment, the elastic pressure member 50 is arranged in series in the stacking direction of the battery cells 12 and interposed between the pair of pressure plates 31, 32. As shown in Figure 4 , the surface pressure of the battery cells 12 is controlled within the appropriate range of surface pressure (the range between the control surface pressure and the lower limit surface pressure), and this makes it possible to control the surface pressure of the battery cells 12 using the energy stored in the elastic pressure member 50 by the deflection amount δ in the expansion / contraction direction M of the elastic pressure member 50.

[0027] As a result, the pressure mechanism 30 of this embodiment can also function as a displacement absorption mechanism in the expansion / contraction direction M of the battery cell 12. In particular, the pressure mechanism 30 of this embodiment does not require fine displacement adjustment using a feed screw in the linear motion mechanism 40 to accommodate the required surface pressure during cell charging and discharging, thereby reducing the workload of the drive mechanism 60.

[0028] In the figure, two dashed lines (control surface pressure, lower limit surface pressure) shown at the top and bottom indicate the range of appropriate surface pressure, and multiple white arrows each show an image of tracking depending on the amount of deflection δ in the extension / contraction direction M of the elastic pressure member 50. Furthermore, in the figure, the hatched arrows shown between the multiple white arrows each show an image of the control device 80 of the pressure mechanism 30 driving the drive mechanism 60 in response to a deficiency in the amount of deflection δ of the elastic pressure member 50 by executing a "pressure control process" described later, thereby controlling the opposing distance between the pair of pressure plates 31, 32.

[0029] [Control Device and Control Method for Pressure Mechanism] Next, a control device 80 and a control method for controlling the pressure mechanism 30 will be described. As shown in Fig. 1 , the control device 80 of this embodiment includes a measurement unit 81 that constantly measures the opposing distance W between the pair of pressure plates 31, 32, and a control unit 82 that controls the drive mechanism 60. A distance sensor is used for the measurement unit 81. As the distance sensor, various sensors can be appropriately used, such as an ultrasonic sensor, an infrared distance sensor, or a laser distance sensor, as long as they can constantly measure the opposing distance W between the pair of pressure plates 31, 32.

[0030] The control unit 82 includes a CPU (Central Processing Unit), a memory, and input / output ports for inputting and outputting various signals. The memory includes, for example, a ROM (Read Only Memory), a RAM (Random Access Memory), and a rewritable non-volatile memory. The CPU executes programs such as a "pressure control process" stored in the memory to perform various controls.

[0031] The control unit 82 is connected to the motor 63 of the drive mechanism 60 via a driver and harnesses (not shown) so as to be able to control the drive of the drive mechanism 60, and is also connected to the vehicle controller 90 via harnesses so as to be able to send and receive necessary information to and from the vehicle controller 90, which controls the entire vehicle. The vehicle controller 90 is also connected to a meter 100 that is installed in the vehicle cabin so as to be visible to the driver of the vehicle. The meter 100 is configured to be able to display information required by the driver in response to a request from the vehicle controller 90.

[0032] Here, the control unit 82 of this embodiment is configured to be able to execute the program for the above-mentioned "pressure control process", and as shown in Fig. 4, is able to control the drive mechanism 60 based on the occasional information on the facing distance W. In detail, when the pressure control process is executed in the control unit 82, as shown in Fig. 5, first, the process proceeds to step S10, where occasional information on the facing distance W measured by the measurement unit 81 is acquired, and in the subsequent step S20, the rate of change Vw (mm / s) of the facing distance W (i.e., the amount of deflection δ (thickness in the expansion / contraction direction M) of the elastic pressure member 50) is calculated.

[0033] Next, the process proceeds to step S30, where the calculated rate of change Vw is compared with the trackability information of the deflection amount δ of the elastic pressure member 50 in the extension / contraction direction M. As a result, if the rate of change Vw is equal to or greater than a predetermined value (the deflection amount δ has difficulty tracking the rate of change Vw), the process proceeds to step S40, where a series of "linear pressure control" is executed in which the drive mechanism 60 is driven to apply pressure together with the elastic pressure by the elastic pressure member 50. On the other hand, if the rate of change Vw is less than the predetermined value (the deflection amount δ can track the rate of change Vw), the process proceeds to step S100, where "elastic pressure control" is executed in which pressure is applied only by tracking the deflection amount δ of the elastic pressure member 50 without driving the drive mechanism 60.

[0034] 6, when the control unit 82 executes the direct pressure control, it first proceeds to step S41 to detect the SOC (State Of Charge), then in step S42 it calculates the thickness of the battery module 10 (plurality of battery cells 12) in the stacking direction, and then proceeds to step S43. In step S43, it checks whether or not there is a drive request for the drive mechanism 60. If there is a drive request (Yes), it proceeds to step S50, and if not (No), it returns to the previous step.

[0035] In step S50, a series of processes required for driving the drive mechanism 60 is executed. In the example of the same figure, in direct acting pressure control, the motor 63 of the drive mechanism 60 is driven by current and voltage. In this embodiment, the rotation speed of the motor 63 is controlled by voltage control, and the drive speed of the motor 63 is controlled by controlling the voltage of the motor 63 while the motor 63 is being driven. Also, in this embodiment, the torque of the motor 63 is controlled by current control, and the pressure applied to the all-solid-state battery is controlled by controlling the current of the motor 63 while the motor 63 is being driven.

[0036] That is, in this embodiment, when the motor 63 is driven, steps S51 and S52 are executed simultaneously in parallel. In step S51, the rotation speed of the motor 63 is detected, and in step S52, the current of the motor 63 is detected. In step S53 following step S52, it is determined whether the pressure applied to the battery module 10 in the stacking direction of the battery cells 12 is equal to or less than a predetermined specified pressure. Here, the method for measuring the pressure applied to the battery modules 10 in the stacking direction of the battery cells 12 is to measure the opposing distance W between the pair of pressure plates 31, 32 and calculate the pressure applied to the springs 51 that make up the elastic pressure member 50 using the formula: spring constant × number of springs × opposing distance (F = kx).

[0037] If the pressure applied to the battery module 10 (battery cells 12) is equal to or less than the specified pressure (Yes), the process proceeds to step S71. If not (No), the process proceeds to step S72. In step S71, the current of the motor 63 is increased to a value higher than the current value, and the process returns to step S41. In step S72, the current of the motor 63 is decreased to a value lower than the current value, and the process returns to step S41.

[0038] Following step S51, steps S54 and S55 are executed simultaneously. In step S54, the opposing distance W is detected. In the following step S56, it is determined whether the opposing distance W is equal to or less than a preset assumed distance. If the opposing distance W is equal to or less than the assumed distance (Yes), the process proceeds to step S61. If not (No), the process proceeds to step S62. In step S55, it is determined whether the rate of change Vw is equal to or greater than a preset assumed rate of expansion / contraction in the stacking direction of the battery module 10 (battery cells 12).

[0039] Here, the method for measuring the rate of expansion and contraction of the battery module 10 (battery cells 12) involves continually measuring the opposing distance W between the pair of pressure plates 31, 32, and calculating the rate of change Vw (mm / s) of expansion and contraction from the relationship between the opposing distance W and time at any given time. Note that by calculating the SOC (State Of Charge) using a well-known battery management system (BMS), the rate of change Vw can be calculated from the relationship between the thickness of the battery module 10 for each SOC.

[0040] If the change rate Vw is equal to or greater than the expected inflation / deflation rate (Yes), the process proceeds to step S61. If not (No), the process proceeds to step S62. In step S61, the voltage of the motor 63 is increased above the current value to accelerate the motor 63, and the process returns to step S41. In step S72, the voltage of the motor 63 is decreased below the current value to decelerate the motor 63, and the process returns to step S41.

[0041] [Effects of the Pressure Mechanism Control Device and Control Method] Next, the effects of the control device 80 and control method for the pressure mechanism 30 of this embodiment will be described. Incidentally, an all-solid-state battery (ASSB) requires a pressure mechanism that constantly applies a predetermined range of surface pressure to the battery cells while following changes in the thickness of the battery cells in the stacking direction in response to charging and discharging. However, if the maximum output required by the vehicle is high, the rate at which the thickness of the battery cells changes accordingly also increases.

[0042] As a result, the rotation speed or gear ratio of the motor driving the pressure mechanism increases, which increases the module size and reduces the energy density (including cost and weight). Higher rotation speeds also reduce the durability of the pressure mechanism. In this way, increasing the required output from the vehicle side requires larger pressure mechanism components, which creates the potential problem of battery packs that use all-solid-state batteries having to sacrifice energy density, cost, and weight.

[0043] 1 , the control device 80 of this embodiment includes a measurement unit 81 that measures the opposing distance W between the pair of pressure plates 31, 32, and a control unit 82 that controls the drive mechanism 60, and the linear motion direction of the linear motion mechanism 40 and the deflection direction of the spring of the elastic pressure member 50 are arranged in series with respect to the expansion / contraction direction M. As a result, when applying pressure to the battery module 10 (battery cells 12), the control unit 82 can reduce the control load by stopping the motor 63 within a range that the deflection amount δ of the elastic pressure member 50 can follow.

[0044] In particular, when controlling the pressure mechanism 30, the control unit 82 of this embodiment, as shown in FIG. 5 , is able to perform direct acting pressure control in which pressure is applied together with the pressure force using the deflection of the elastic body of the pressure member 50 by driving the drive mechanism 60 in response to the rate of change Vw of the facing distance W based on the relationship between the real-time information on the facing distance W and the amount of deflection δ of the pressure member 50, if the rate of change Vw is equal to or greater than a predetermined value, and perform elastic pressure control in which pressure is applied only by the pressure force using the deflection of the elastic body of the pressure member 50 without driving the drive mechanism 60, if the rate of change Vw is less than the predetermined value.

[0045] As a result, the control device 80 and control method according to this embodiment execute the direct acting pressure control and elastic pressure control shown in FIG. 5 , thereby enabling efficient control of the pressure mechanism 30 with high control responsiveness and in the smallest possible space. Furthermore, even when the drive mechanism 60 is stopped, the elastic pressure member 50 can control the pressure mechanism 30 within a range that it can independently follow. In particular, by executing elastic pressure control, the elastic pressure member 50 can independently follow control response when there is a delay in control response or when the drive mechanism 60 is stopped. Therefore, when the drive mechanism 60 is stopped, the elastic pressure member 50 can independently follow control response due to variations in the SOC and the thickness of the battery cells 12 within a range that it can follow the deflection amount δ, thereby improving control robustness and reducing the motor load on the drive mechanism 60 while always applying an appropriate pressure force according to the thickness of the battery cells 12 [Invention 1], [Invention 2], and [Invention 9].

[0046] Furthermore, according to the control device 80 and control method of this embodiment, as shown in FIG. 6 , the control unit 82 drives the motor 63 of the drive mechanism 60 during direct-acting pressure control, and while the motor 63 is being driven, the control unit 82 controls the voltage of the motor 63 to control the drive speed of the motor 63, and controls the current of the motor 63 to control the pressure force applied to the battery module 10. This is advantageous for controlling the pressure force applied to the battery module 10 as desired and for tracking the moving speed of the pair of pressure plates 31, 32 over the opposing distance W [Invention 3].

[0047] Furthermore, the control device 80 and control method for the pressure mechanism 30 of this embodiment can control the drive mechanism 60 when the required output exceeds the output of the drive mechanism 60. In other words, in this embodiment, as shown in FIG. 7 (a), the required pressure applied to the battery module 10 fluctuates in response to the required output exceeding the output of the drive mechanism 60 (the required load during cell operation indicated by the dashed line and arrow in FIG. 7 (a)). In contrast, as shown in FIG. 7 (b), even when the required output exceeds the maximum output of the motor 63, the elastic pressure member 50 can deflect the required output for a certain period of time as long as it is within the range of deflection δ (the arrow in FIG. 7 (b)). Therefore, the responsiveness of the drive mechanism 60 required for the required output can be slowed (in other words, it can be intentionally prevented from completely responding to minute changes in cell thickness) [Invention 4].

[0048] Furthermore, the control device 80 and control method for the pressure mechanism 30 of this embodiment are suitable for controlling the drive mechanism 60 during charging because the increase in pressure can be absorbed by the elastic pressure member 50. That is, as shown in FIG. 8 (b), the thickness of the battery cell 12 in the expansion / contraction direction M increases as charging progresses. In response to the increase in the thickness of the battery cell 12 in the expansion / contraction direction M during charging, the required cell operation load to be applied must be maintained within a predetermined range (the range indicated by the arrow in FIG. 8 (a)), as shown in FIG. 8 (a). Even when the motor 63 is stopped, the elastic pressure member 50 can deflect to maintain the required load for a certain period of time. Therefore, as shown in FIG. 8 (a), the combination of the repeated ON / OFF operation of the motor 63 and the load increase due to the deflection of the elastic pressure member 50 can eliminate or mitigate the need for high-precision responsiveness of the drive mechanism 60 during charging [Invention 5].

[0049] Furthermore, the control device 80 and control method for the pressure mechanism 30 of this embodiment are suitable for controlling the drive mechanism 60 when the vehicle is stopped. That is, as shown in FIG. 9 (a), when the vehicle is stopped, the thickness of the battery cells 12 in the expansion / contraction direction M gradually decreases as the battery cells 12 self-discharge, as shown in the graph in FIG. 9 (b). In this case, as shown by the dashed line at the bottom in FIG. 9 (a), a required cell-holding load must be applied to maintain the orientation of the multiple battery cells 12 in accordance with the decrease in the thickness of the battery cells 12 in the expansion / contraction direction M during discharge. This required cell-holding load may be lower than the predetermined range of the required cell operation load (the range indicated by the arrow in FIG. 9 (a)). In contrast to this, in this embodiment, the compression load of the pressure member 50 can be released to accommodate the reduction in thickness even when the vehicle is stopped, so as long as the amount of deflection of the pressure member 50 is within a range that can accommodate the amount of thickness contraction in the expansion / contraction direction M of the battery cell 12, the amount of power consumed by the drive mechanism 60 when the vehicle is stopped can be eliminated or reduced [Invention 6].

[0050] Furthermore, the control device 80 and control method for the pressure mechanism 30 of this embodiment are suitable for controlling the drive mechanism 60 during normal vehicle operation. That is, as shown in FIG. 10 (b), during normal vehicle operation, the thickness of the battery cells 12 increases and decreases from moment to moment, as shown in FIG. 10 (b). With this embodiment, as shown in FIG. 10 (a), even during normal vehicle operation, the amount of deflection of the elastic pressure member 50 itself can follow this change in the thickness of the battery cells 12 within the range of the required cell operation load (the range indicated by the arrow in FIG. 10) without falling below the range. Therefore, high-precision responsiveness of the drive mechanism 60 during normal operation can be eliminated or alleviated [Invention 7].

[0051] Furthermore, in the control device 80 and control method for the pressure mechanism 30 of this embodiment, it is preferable to employ springs 51 as the elastic pressure members, as with the elastic pressure members 50 of the above-described embodiment. In particular, it is desirable to arrange a plurality of springs 51 in parallel between the cell-side pressure plate 32 and the drive-side pressure plate 31. This configuration is advantageous for distributing the pressure on the battery module 10 while always applying an appropriate pressure in response to changes in the thickness of the battery cells 12 [Invention 8].

[0052] As described above, the control device 80 and control method for the pressure mechanism 30 of this embodiment can reduce the load on the motor 63 of the drive mechanism 60 while always applying an appropriate pressure in accordance with changes in the thickness of the battery cells 12. Note that the control method and control device for the battery pressure mechanism, and the vehicle according to the present invention are not limited to the above-described embodiment, and various modifications are possible without departing from the spirit of the present invention.

[0053] REFERENCE SIGNS LIST 1 Battery pack 10 Battery module (all-solid-state battery) 12 Battery cell (all-solid-state battery) 20 Storage case 30 Pressurizing mechanism 31 Cell-side pressure plate 32 Drive-side pressure plate 40 Linear motion mechanism 41 Screw shaft 42 Nut 50 Elastic pressure member 51 Spring (cylindrical coil spring) 52 Slide guide 60 Drive mechanism 61 Worm 62 Worm wheel 63 Motor 70 Drive unit holder 71 Pinion shaft 72 Pinion 80 Control device 81 Measuring unit 82 Control unit 90 Vehicle controller 100 Meter M Extension / contraction direction W Facing distance

Claims

1. A method for controlling a pressurizing mechanism that pressurizes an all-solid-state battery in its expansion / contraction direction, wherein the pressurizing mechanism includes a pair of pressure plates disposed opposite to each other in the expansion / contraction direction with respect to the all-solid-state battery, a resilient member interposed between the pair of pressure plates to apply a pressing force to the all-solid-state battery, a linear motion mechanism capable of expanding and contracting the opposing distance between the pair of pressure plates, and a driving mechanism for driving the linear motion mechanism. When pressurizing the all-solid-state battery, the opposing distance between the pair of pressure plates is measured at any time, and in response to the measured change rate of the opposing distance, when the change rate is equal to or greater than a predetermined value, the driving mechanism is driven to perform pressurization together with the resilience of the resilient member, and when the change rate is less than the predetermined value, pressurization is performed only by the resilient member without driving the driving mechanism. A method for controlling a battery pressurizing mechanism, characterized in that.

2. A control device used for a pressurizing mechanism that pressurizes an all-solid-state battery in its expansion / contraction direction, wherein the pressurizing mechanism includes a pair of pressure plates disposed opposite to each other in the expansion / contraction direction with respect to the all-solid-state battery, a resilient member interposed between the pair of pressure plates to apply a pressing force to the all-solid-state battery, a linear motion mechanism capable of expanding and contracting the opposing distance between the pair of pressure plates, and a driving mechanism for driving the linear motion mechanism. The control device includes a measuring unit for measuring the opposing distance between the pair of pressure plates at any time, and a control unit for controlling the driving mechanism. The control unit executes a pressurization control process for controlling the pressurization of the all-solid-state battery, and in response to the measured change rate of the opposing distance, when the change rate is equal to or greater than a predetermined value, a linear motion pressurization control is executed to drive the driving mechanism to perform pressurization together with the resilience of the resilient member, and when the change rate is less than the predetermined value, a resilient pressurization control is executed to perform pressurization only by the resilient member without driving the driving mechanism. A control device for a battery pressurizing mechanism, characterized in that.

3. The control unit drives the motor of the driving mechanism during the linear motion pressurization control, and during the driving of the motor, controls the driving speed of the motor by controlling the voltage of the motor, and controls the pressing force applied to the all-solid-state battery by controlling the current of the motor. The control device for a battery pressurizing mechanism according to claim 2.

4. The control unit executes the control of the drive mechanism when the required output exceeds the output by the resilient pressure control during the execution of the pressure control process in the battery pressure mechanism control device according to claim 2.

5. The control unit executes the pressure control process during charging of the all-solid-state battery in the battery pressure mechanism control device according to claim 2.

6. The all-solid-state battery is mounted on a vehicle, and the control unit executes the pressure control process when the vehicle stops in the battery pressure mechanism control device according to claim 2.

7. The all-solid-state battery is mounted on a vehicle, and the control unit executes the pressure control process during normal operation of the vehicle in the battery pressure mechanism control device according to claim 2.

8. The resilient member is a spring in the battery pressure mechanism control device according to claim 2.

9. A vehicle equipped with an all-solid-state battery, comprising a pressure mechanism that pressurizes the all-solid-state battery in its expansion and contraction direction, and a control device that controls the pressure mechanism, wherein the control device has the battery pressure mechanism control device according to any one of claims 2 to 8.

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