Holding mechanism

Abstract

To provide a holding mechanism that can appropriately maintain the surface pressure applied to a battery in accordance with changes in the characteristics of a mechanism that applies a compressive load to the battery.SOLUTION: A holding mechanism that compresses a battery stack in the stacking direction and maintains the surface pressure applied to the stack includes a load application unit that applies a compressive load to the stack, an electric motor that generates the driving force required to operate the load application unit, and a detection unit that detects a first detection value related to a characteristic of the stack and a second detection value related to a characteristic of the load application unit, and the detection unit detects the first detection value and the second detection value when charging of the battery is completed or when a vehicle in which the battery is installed is stopped, and the load application unit corrects the target load value of the compressive load to be applied to the stack when operation of the load application unit is stopped, on the basis of the first detection value and the second detection value when charging of the battery is completed or when the vehicle is stopped.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a retention mechanism. [Background technology]

[0002] A module is known that includes a first member, which is a battery in which pressure fluctuations occur along one axis, a pair of second members arranged at both ends of the first member in the one axis direction, and a restraining member that pressurizes and restrains the first member and the pair of second members (Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-150027 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the technology described in Patent Document 1 is a technology that maintains the surface pressure applied to the battery in accordance with the expansion and contraction of the battery, and has the problem that the surface pressure cannot be maintained appropriately when the surface pressure fluctuates due to changes in the characteristics of the restraint member.

[0005] The problem to be solved by the present invention is to provide a holding mechanism that can appropriately maintain the surface pressure applied to the battery in accordance with changes in the characteristics of the mechanism that applies a compressive load to the battery. [Means for solving the problem]

[0006] The present invention provides a holding mechanism that compresses a battery stack in the stacking direction to maintain the surface pressure applied to the stack, and includes a load application unit that applies a compressive load to the stack, an electric motor that generates the driving force required to operate the load application unit, and a detection unit that detects a first detection value related to the characteristics of the stack and a second detection value related to the characteristics of the load application unit, wherein the detection unit detects the first detection value and the second detection value when charging of the battery is completed or when the vehicle in which the battery is installed is stopped, and the load application unit corrects the target load value of the compressive load to be applied to the stack when operation of the load application unit is stopped, depending on the first detection value and the second detection value when charging of the battery is completed or when the vehicle is stopped, thereby solving the above problem. [Effects of the Invention]

[0007] According to the present invention, the surface pressure applied to the battery can be appropriately maintained in accordance with changes in the characteristics of the mechanism that applies a compressive load to the battery. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of a holding mechanism according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of the transition of the load on the stack after the load application mechanism according to this embodiment stops operating. [Figure 3] FIG. 3 is a flowchart showing a method for correcting the target load value of the compressive load by the load applying mechanism according to this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram showing an example of a holding mechanism according to an embodiment of the present invention. The holding mechanism according to this embodiment compresses the battery stack in the stacking direction to hold the surface pressure applied to the stack. Although not particularly limited, the battery stack according to this embodiment is mounted as a battery in, for example, an electric vehicle or a hybrid vehicle. One example of the battery is an all-solid-state battery, but is not limited to this as long as it is a battery that expands and contracts like a secondary battery.

[0010] The holding mechanism 1 applies a compressive load to the stack 10 in the stacking direction, compressing the stack 10 so as to maintain a surface pressure of a predetermined value or more on the stack 10. As shown in FIG. 1 , the holding mechanism 1 includes a first detection unit 11, a second detection unit 12, a load application mechanism 20 that applies a compressive load to the battery stack 10, a controller 30, and an electric motor 40. The load application mechanism 20 and the controller 30 are examples of components that constitute the function of a "load application unit" described in the claims. In this embodiment, these are described separately, but this is not intended to be limiting; the "load application unit" may also be an integrated mechanism. The first detection unit 11 and the second detection unit 12 are examples of a "detection unit" described in the claims. In this embodiment, the "detection unit" described in the claims may be divided into separate devices, the first detection unit 11 and the second detection unit 12, or may be a single device.

[0011] The laminate 10 is electrically connected to a charging device (not shown). The charging device connected to the laminate 10 is, for example, a device for charging the laminate 10 mounted on an electric vehicle or a hybrid vehicle. Charging the mounted laminate 10 is performed by removing the charging cable from the charging device, attaching the charging gun at the end of the charging cable to the connector of the vehicle's charging port, and then operating the charging start switch.

[0012] The laminate 10 is also electrically connected to a load (not shown) such as a motor. The load is a device that operates using the power of the laminate 10, such as a motor that serves as a drive source for the vehicle, or accessories such as an air conditioner or lights. The discharge of the laminate 10 is executed under the control of the controller 30 in response to a system request or an external power request. The system request corresponds to a command from an on-board computer such as an ECU while the vehicle is running. With regard to the external power request, for example, when an external device such as a mobile terminal commands an air conditioner to operate before the vehicle starts running by setting a timer so that the interior temperature of the vehicle is appropriate when the vehicle starts running, the command from the external device corresponds to the external power request.

[0013] The battery cell included in the laminate 10 is an all-solid-state battery having at least a positive electrode, a solid electrolyte, and a negative electrode. The positive electrode contains at least a positive electrode active material capable of absorbing and releasing an alkali metal such as lithium (Li), sodium (Na), or potassium (K). Although not particularly limited, it preferably contains a positive electrode active material containing sulfur. As the solid electrolyte, for example, a sulfide solid electrolyte or an oxide solid electrolyte can be used, but it is preferable to use a sulfide solid electrolyte. The negative electrode may contain lithium, and preferably contains, for example, lithium metal. The laminate 10 in this embodiment includes multiple battery cells. The battery cells have, for example, a flat plate shape. The multiple battery cells are stacked in the laminate 10 so that the main surfaces of the battery cells are in contact with each other. The laminate 10 expands and contracts in the stacking direction.

[0014] The first detection unit 11 detects a first detection value related to the characteristics of the stack 10. The first detection value is a parameter indicating the state of the stack 10, and includes, for example, the temperature of the stack 10. The first detection unit 11 includes a temperature sensor. The temperature sensor is provided in the stack 10 and detects the temperature of the stack 10. The first detection unit 11 may also detect the surface pressure of the stack 10.

[0015] The second detection unit 12 detects a second detection value related to the characteristics of the load applying mechanism 20. The characteristics of the load applying mechanism 20 include, for example, the holding characteristics of the load applying mechanism 20 holding the stack 10 and the operating characteristics of the load applying mechanism 20. The second detection value is a status value that affects the characteristics of the load applying mechanism 20, and is a parameter that indicates the status of the load applying mechanism 20 and / or a parameter that indicates the status of the electric motor 40 that drives the load applying mechanism 20. For example, the second detection value includes the temperature of the load applying mechanism 20. The second detection unit 12 includes a temperature sensor. The temperature sensor is provided in the load applying mechanism 20 and detects the temperature of the load applying mechanism 20.

[0016] The temperature of the load application mechanism 20 is not limited to the temperature of the load application mechanism 20 itself, but may be, for example, the temperature of a fluid for applying a compressive load to the stack 10. In this embodiment, the load application mechanism 20 applies a compressive load to the stack 10 by the pressure of the fluid. The fluid is, for example, oil. If the load application mechanism 20 is hydraulic, the oil viscosity decreases at high oil temperatures, making oil leakage within the hydraulic chamber more likely. Therefore, until the oil temperature drops below a predetermined temperature, oil leakage from the hydraulic chamber may cause a decrease in the holding force that maintains the surface pressure of the stack 10. In contrast, in this embodiment, as will be described later, the required holding force can be maintained by increasing the load value of the stack 10 by a predetermined value or more when charging is completed or the vehicle is stopped.

[0017] The fluid may also be, for example, compressed gas. When the load application mechanism 20 is driven by the pressure of compressed gas, a decrease in the gas temperature can reduce the gas volume, thereby reducing the holding force that maintains the surface pressure of the stack 10. In contrast, in this embodiment, as described below, by increasing the load value of the stack 10 by a predetermined value or more when charging is completed or the vehicle is stopped, the necessary holding force can be maintained even when the operating speed is reduced the next time the vehicle is started. Furthermore, since the temperature of the fluid that operates the actuator can be detected, the holding mechanism 1 can also control the driving force of the actuator according to the temperature of the fluid. When the fluid temperature is low and viscous resistance increases, the holding mechanism 1 can generate the necessary driving force by increasing the driving force of the actuator.

[0018] The second detection value may include the voltage of the electric motor 40. The second detection unit 12 includes a voltage sensor. The voltage sensor is a sensor for detecting the voltage of the electric motor 40.

[0019] In this embodiment, the first detector 11 and the second detector 12 detect the first detected value and the second detected value, respectively, when charging of the battery is completed or when the vehicle in which the battery is mounted is stopped.

[0020] Furthermore, the second detection unit 12 may detect, as the second detection value, the operation frequency, operation time, or drive energy amount of the load applying mechanism 20 during a predetermined period before the battery charging is completed or the vehicle is stopped. The operation frequency is, for example, the number of operations during the predetermined period.

[0021] The load application mechanism 20 applies a compressive load to the stack 10 by compressing the stack 10 along the stacking direction of the stack 10. The load application mechanism 20 in this embodiment is not particularly limited as long as it is a mechanism that can apply a compressive load to the stack 10, but for example, as shown in FIG. 1 , it has a pair of pressure plates 21 and a plurality of shafts 22.

[0022] The electric motor 40 generates the driving force required to operate the load application mechanism 20. The method of operating the load application mechanism 20 using the electric motor 40 is not particularly limited. For example, the electric motor 40 directly drives the electrically powered load application mechanism 20. Specifically, the electric motor 40 rotates a gear in response to a command from the controller 30. The gear converts the driving force from the electric motor 40 into movement of the pressure plate 21 in the stacking direction. The pressure plate 21 moves up and down by the driving force transmitted via the gear. In this embodiment, the upper pressure plate 21 is a plate member that can move along the stacking direction, and the lower pressure plate 21 is a plate member that does not move along the stacking direction. In this embodiment, the load applied to the stack 10 can be increased by moving the upper pressure plate 21 downward in the figure, and the load applied to the stack 10 can be decreased by moving the upper pressure plate 21 upward in the figure.

[0023] Specifically, the lower pressure plate 21 is fixed to the shaft 22 and supports the stack 10. On the other hand, the upper pressure plate 21 is not fixed to the shaft 22, but is movable along the extension direction of the shaft 22, and applies pressure to the stack 10 from above in response to the driving force transmitted from the electric motor 40. The upper pressure plate 21 can also move along the stacking direction in response to the expansion and contraction of the stack 10 due to charge and discharge, and the expansion and contraction of the stack 10 due to changes in the load applied by the upper pressure plate 21 to the stack 10.

[0024] The electric motor 40 may also be used as the driving force for a hydraulic pump. In this case, the load application mechanism 20 is operated by hydraulic pressure. For example, the load application mechanism 20 moves the pressure plate 21 in the stacking direction by adjusting the hydraulic pressure. The electric motor 40 may also be used as the driving force for a pneumatic pump. In this case, the load application mechanism 20 is operated by air pressure. For example, the load application mechanism 20 moves the pressure plate 21 in the stacking direction by adjusting the air pressure.

[0025] The controller 30 controls a load value indicating the load that the load application mechanism 20 applies to the stack 10. The controller 30 is composed of a memory such as a ROM or a RAM, and a processor such as a CPU. The controller 30 corrects a target load value of the compressive load to be applied to the stack 10 when the operation of the load application mechanism 20 stops, according to the detection values ​​detected by the first detection unit 11 and the second detection unit 12. The controller 30 controls the load value of the load application mechanism 20 so that it becomes the corrected target load value. Specifically, the controller 30 can adjust the load value of the compressive load to be applied to the stack 10 to the target load value by controlling the electric motor 40.

[0026] In this embodiment, the load application mechanism 20 operates in response to a command from the controller 30 to apply a compressive load to the stack 10, thereby adjusting the surface pressure. However, the load application mechanism 20 stops operating when the battery finishes charging or when the vehicle stops. A stopped load application mechanism 20 does not adjust the value of the compressive load in response to fluctuations in the surface pressure, even if the surface pressure fluctuates due to a change in the state of the stack 10. Therefore, while the load application mechanism 20 is stopped, the surface pressure of the stack 10 may become too small or too large.

[0027] Here, an example of fluctuation in the load applied to the stack 10 after the load application mechanism 20 is deactivated will be described with reference to FIG. 2. FIG. 2 is a diagram showing an example of the change in the load of the stack 10 after the load application mechanism 20 according to this embodiment is deactivated. In FIG. 2, the vertical axis represents the load of the stack 10, and the horizontal axis represents time. The solid line graph shows the change in the actual load on the stack 10, and the dotted line graph shows the change in the load of the stack 10 when the temperature of the stack 10 and the temperature of the load application mechanism 20 are not included in the fluctuation factors. FIG. 2 shows the change in the load of the stack 10 from the time t1 when the vehicle stops to the time t5 when the vehicle restarts. In the example of FIG. 2, the load application mechanism 20 stops operating from the time t1 when the vehicle stops. Note that in this embodiment, the load application mechanism 20 may stop operating from the time t3 when battery charging is completed. The time when battery charging is completed is, for example, when the battery charge rate reaches 100%.

[0028] In the example of FIG. 2, the load of the laminate 10 is adjusted to a target load value P1 at the time (t1) when the vehicle stops. From this point, while the vehicle is stopped, the laminate 10 begins to contract due to natural cooling of the battery, and the actual load of the laminate 10 decreases from P1. Thereafter, between time t2 and time t3, the battery is charged. The temperature of the laminate 10 increases due to battery charging, and the actual load of the laminate 10 increases. In the example of FIG. 2, the solid line graph shows the actual load of the laminate 10, which includes the temperature of the laminate 10 and the temperature of the load application mechanism 20 as variation factors, and therefore the increase in the load of the laminate 10 is greater than that shown by the dotted line graph when the temperature of the laminate 10 and the temperature of the load application mechanism 20 are not included as variation factors.

[0029] From the time when the battery charging is completed (t3), the temperatures of the stack 10 and the load application mechanism 20 decrease, and the load of the stack 10 decreases again. The solid line graph shows the actual load of the stack 10, which includes the temperature of the stack 10 and the temperature of the load application mechanism 20 as fluctuation factors. Therefore, the decrease in the load of the stack 10 is greater than the dotted line graph, which does not include the temperature of the stack 10 and the temperature of the load application mechanism 20 as fluctuation factors. Note that, as shown in the solid line graph, the load of the stack 10 increases when the temperature around the stack 10 increases and decreases when the temperature around the stack 10 decreases. As shown in FIG. 2, after the battery charging is completed, the load of the stack 10 fluctuates with the temperature, but gradually decreases overall due to fluctuation factors such as natural discharge and misalignment of the load application mechanism 20. Then, at a certain time (t4), the temperatures of the stack 10 and the load application mechanism 20 stabilize, and the load of the stack 10 no longer fluctuates due to the temperature of the stack 10 and the load application mechanism 20 as fluctuation factors. After time t4, the load on the stack 10 fluctuates up and down due to the temperature as a fluctuating factor.

[0030] As shown in the example of Figure 2, the load on the laminate 10 fluctuates up and down due to various factors between the time the load application mechanism 20 is stopped and the time it is next started. Even if the load on the laminate 10 fluctuates up and down, if the fluctuation is small, it will fall within a predetermined tolerance range. For example, when the temperature of the laminate 10 changes, the dimensions of the laminate 10 change due to expansion and contraction of the laminate 10, causing the load on the laminate 10 to fluctuate. However, since the predetermined tolerance range has a certain width, some fluctuation can be tolerated without correction. Furthermore, the load on the laminate 10 also fluctuates depending on the temperature of the load application mechanism 20, but similarly, some fluctuation can be tolerated without correction.

[0031] Even if the load on the laminate 10 fluctuates up and down, as long as it remains within a predetermined allowable range, the charge and discharge output of the battery can be maintained appropriately. However, if the load on the laminate 10 fluctuates up and down excessively and exceeds the predetermined allowable range, the following problems occur. If the load on the laminate 10 falls below a predetermined allowable lower limit, the resistance of the laminate 10 increases, reducing the charge and discharge capability of the battery. If the load on the laminate 10 exceeds the predetermined allowable lower limit, the load on the laminate 10 becomes excessive, causing internal damage to the laminate 10 and resulting in a short circuit. Furthermore, if discharge progresses during a vehicle restart and the load on the laminate 10 falls below the predetermined allowable lower limit, it takes time for the load on the laminate 10 to increase above the predetermined allowable lower limit, making it impossible for the vehicle to suddenly accelerate immediately after the restart, or limiting acceleration performance.

[0032] Furthermore, if the load on the laminate 10 is below a predetermined allowable lower limit at the start of charging, the resistance of the laminate 10 increases, causing the laminate 10 to overheat during charging. If the load on the laminate 10 is increased above the lower limit at which charging can begin in order to avoid overheating of the laminate 10, it takes time, resulting in a delay in the start of charging. Alternatively, the charging speed decreases, resulting in an increase in charging time. Furthermore, if the load on the laminate 10 exceeds a predetermined allowable upper limit at the start of charging, the interior of the laminate 10 may be damaged by excessive pressure. If charging is started in this state, the load on the laminate 10 will increase further, causing the interior of the laminate 10 to be damaged.

[0033] The following are examples of cases where the load applied to the stack 10 by the load application mechanism 20 fluctuates significantly. For example, when a gas-filled spring mechanism is used as the load application mechanism 20, changes in the gas temperature cause large fluctuations in the load applied to the stack 10 due to changes in the gas pressure. Furthermore, when the load application mechanism 20 is electrically driven, if the oil or grease temperature of the sliding parts is higher than a predetermined value, the viscous resistance of the sliding parts decreases, and the load application mechanism 20 is moved by the compressive load of the stack 10, changing its holding position until the temperature drops below the predetermined value, and the load applied to the stack 10 may decrease. Furthermore, when a hydraulic mechanism is used as the load application mechanism 20, if the oil temperature in the hydraulic chamber is higher than a predetermined value, the viscosity of the oil is low, and oil leakage from the seal of the hydraulic chamber may reduce the hydraulic pressure, causing a decrease in the load on the stack 10.

[0034] To address the above-described problems, in this embodiment, even if the load on the stack 10 fluctuates after the load application mechanism 20 is deactivated, the controller 30 corrects the target load value of the compressive load applied to the stack 10 when the load application mechanism 20 is deactivated, and controls the load value of the compressive load of the load application mechanism 20 to be adjusted to the target load value so that the load on the stack 10 falls within a predetermined allowable range. This allows the battery charge / discharge output to be maintained appropriately even while the load application mechanism 20 is deactivated. Furthermore, by maintaining the load on the stack 10 within a predetermined allowable range while the vehicle is stopped, battery charge / discharge can be started without delay the next time the vehicle is started.

[0035] In particular, since the temperature of the stack 10 can be directly detected by a sensor or estimated from the charge / discharge state, the load on the stack 10 can be corrected based on the temperature of the stack 10 at the end of charging or when driving is stopped. However, the temperature characteristics of the load application mechanism 20 have not been considered until now. To accommodate the expansion and contraction of the stack 10, a method has been proposed in which a spring is sandwiched between the stack 10 and the load application mechanism 20 to absorb dimensional changes due to slight expansion and contraction and maintain the compressive load applied to the stack 10 within a certain range. However, if fluctuations in the load on the stack 10 are simultaneously affected by temperature changes in both the stack 10 and the load application mechanism 20, the fluctuation range of the load on the stack 10 will be large. Therefore, it is desirable to correct the value of the compressive load on the stack 10 at the end of charging or when driving is stopped so that the load on the stack 10 is maintained within a predetermined tolerance range at the start of the next charging or driving. Furthermore, the stack 10 and the load application mechanism 20 are in contact with each other over a wide area to distribute surface pressure, resulting in high thermal conductivity. Therefore, even if the temperature of one is high, heat is dissipated to the other, affecting the temperature of the other, so it is desirable to take both temperatures into consideration. Therefore, in this embodiment, the temperatures of both the laminate 10 and the load application mechanism 20 are detected, and the value of the compressive load of the laminate 10 is corrected according to each temperature, thereby making it possible to appropriately maintain the surface pressure of the laminate 10 while the load application mechanism 20 is not operating.

[0036] In this embodiment, the controller 30 corrects the target load value of the compressive load to be applied to the stack 10 when the load application mechanism 20 stops operating, based on the first detection value and the second detection value obtained when the battery charging is completed or the vehicle is stopped. For example, the first detection value may include the temperature of the stack 10. The second detection value may include the temperature of the load application mechanism 20. First, the controller 30 acquires the temperature of the stack 10 and / or the load application mechanism 20 from the first detection unit 11 and / or the second detection unit 12 when the battery charging is completed or the vehicle is stopped. Next, the controller 30 compares the acquired temperature of the stack 10 and / or the load application mechanism 20 with a predetermined temperature. Then, when the temperature of the stack 10 and / or the load application mechanism 20 when the battery charging is completed or the vehicle is stopped is higher than the predetermined temperature, the controller 30 corrects the target load value so that the target load value is higher than the target load value when the temperature of the stack 10 and / or the load application mechanism 20 is lower than the predetermined temperature. The target load value when the temperature of the laminate 10 and / or the load application mechanism 20 is lower than a predetermined temperature is a normal target load value, for example, a load value for maintaining a surface pressure appropriate for the expansion and contraction state of the laminate 10 when the battery charging is completed or the vehicle is stopped.

[0037] In the example of FIG. 2, the controller 30 sets a load range (R) in which normal charge / discharge output of the stack 10 is possible when charging of the battery is completed or the vehicle is stopped. The load range is a range between the maximum load range value and the minimum load range value. The target load value when the load application mechanism 20 stops operating is a value set within the load range. The maximum load range value is a value that is lower than a predetermined allowable upper limit value by a predetermined load value. In FIG. 2, the difference between the allowable upper limit value and the maximum load range value is a predetermined load value D1. The predetermined allowable upper limit value is a value that is set in advance. The predetermined load value is a value that is set in accordance with a first detection value, for example, the temperature of the stack 10. The minimum load range value is a value that is higher than a predetermined allowable lower limit value by a predetermined load value. In FIG. 2, the difference between the allowable lower limit value and the minimum load range value is a predetermined load value D2. The predetermined allowable lower limit value is a value that is set in advance. The predetermined load value is a value that is set in accordance with the first detection value and the second detection value.

[0038] For example, when the temperature of the stack 10 and / or the load applying mechanism 20 is higher than a predetermined temperature, the controller 30 sets the minimum value of the load range to a value that is higher than the allowable lower limit by a predetermined load value, and sets the target load value within the load range. The target load value is set so that the estimated fluctuation range of the load value from when the vehicle is stopped to when it is restarted falls within the load range. As described above, by setting the minimum value of the load range in an increasing direction, the target load value is also corrected in an increasing direction.

[0039] Furthermore, when the battery charging is completed or the vehicle is stopped, the controller 30 may acquire from the second detector 12 the operation frequency, operation time, or drive energy amount of the load applying mechanism 20 for a predetermined period prior to the battery charging completion or vehicle stop. The controller 30 determines whether the acquired operation frequency, operation time, or drive energy amount is equal to or greater than a predetermined value, and if so, determines that the temperature of the load applying mechanism 20 at the battery charging completion or vehicle stop is higher than a predetermined temperature. When the load applying mechanism 20 is operated under high load for a long period of time, if the load applying mechanism 20 is driven by an electric motor 40, the temperature of the electric motor 40 increases. If the load applying mechanism 20 is operated by hydraulic or pneumatic pressure, the temperature of the fluid increases. Furthermore, the temperature increases due to friction at the sliding portions of the laminate 10 that receive the compressive load. Because of this temperature rise, the load of the stack 10 is likely to decrease after the load applying mechanism 20 stops operating, but the holding mechanism 1 can maintain the load of the stack 10 after operation stops within a predetermined allowable range by correcting in advance the value of the compressive load of the stack 10 in an increasing direction. Also, because a temperature sensor that directly detects the temperature of the load applying mechanism 20 is not required, the holding mechanism 1 can be made smaller and less expensive.

[0040] The controller 30 may also correct the target load value based on the temperatures of the stack 10 and the load applying mechanism 20 when the battery starts charging or the vehicle starts running. First, the controller 30 acquires the temperatures of the stack 10 and the load applying mechanism 20 when the battery starts charging or the vehicle starts running from the first detection unit 11 and the second detection unit 12. Next, the controller 30 determines whether the temperatures of the stack 10 and the load applying mechanism 20 when the battery starts charging or the vehicle starts running are lower than a predetermined temperature. Then, if the temperatures of the stack 10 and the load applying mechanism 20 when the battery starts charging or the vehicle starts running are lower than the predetermined temperature, the controller 30 corrects the target load value so that the target load value is higher than the target load value when the temperatures of the stack 10 and the load applying mechanism 20 are higher than the predetermined temperature. If the temperature of the load applying mechanism 20 is low, the operational responsiveness of the load applying mechanism 20 decreases. Therefore, when the load of the stack 10 decreases due to contraction of the stack 10 while the vehicle is running, increasing the target load value increases the difference between the actual compressive load and the target load value, and increases the command value for the drive torque of the electric motor 40. This increases the operational responsiveness of the load application mechanism 20, allowing the load of the stack 10 to be maintained within a predetermined allowable range. Furthermore, when the surface pressure of the stack 10 increases during charging, the load application mechanism 20 can be operated using the load applied from the stack 10. Therefore, it is possible to save drive energy by having the holding mechanism 1 use the load applied from the stack 10 rather than actively operating the load application mechanism 20. Furthermore, by increasing the target load value, the holding mechanism 1 also increases the surface pressure of the stack 10, allowing the holding mechanism 1 to actively use the load applied from the stack 10 to operate the load application mechanism 20. Furthermore, since the deviation between the target load value and the actual value of the compressive load is reduced even when the operational response of the load application mechanism 20 is reduced, the holding mechanism 1 can reduce the command value of the driving force of the electric motor 40 and thereby reduce the operating energy of the electric motor 40.

[0041] In this embodiment, the second detection value may include the voltage of the electric motor 40 that operates the load application mechanism 20. The controller 30 acquires the voltage at the end of battery charging or when the vehicle is stopped from the second detection unit 12. If the acquired voltage is lower than a predetermined voltage, the controller 30 corrects the target load value so that the target load value is increased by at least the predetermined load value compared to the target load value when the voltage is higher than the predetermined voltage. Because the operating speed of the load application mechanism 20 decreases when the voltage is low, increasing the target load value of the load application mechanism 20 at the end of charging or when the vehicle is stopped by at least the predetermined value allows the required surface pressure of the stack 10 to be maintained even when the operating speed decreases and the control speed of the surface pressure of the stack 10 decreases at the next start. For example, in the example of FIG. 2, when the voltage of the electric motor 40 is lower than the predetermined voltage, the controller 30 sets the minimum value of the load range to a value that is a predetermined load value higher than the allowable lower limit, thereby setting the target load value within the load range. By increasing the minimum value of the load range, the target load value is also corrected to increase.

[0042] Furthermore, if the battery recharges or the vehicle starts running within a predetermined time after the battery charging is completed or the vehicle is stopped, the controller 30 may correct the target load value in the opposite direction to the correction of the target load value when the load application mechanism 20 is deactivated. If the value of the compressive load applied to the stack 10 is corrected higher when the battery charging is completed or the vehicle is stopped, assuming that the battery will be left in that state for a long time after the battery charging is completed or the vehicle is stopped, the surface pressure of the stack 10 may become excessive if recharges or running starts immediately after the compressive load value is adjusted higher. Therefore, if the battery recharges or running starts within a predetermined time after the battery charging is completed or the vehicle is stopped, the target load value may be corrected in the opposite direction in advance to lower the load of the stack 10, thereby preventing the load of the stack 10 from falling outside the predetermined allowable range.

[0043] As described above, in this embodiment, the controller 30 sets a predetermined load value to be added to the allowable lower limit value based on the determination result of the temperature of the stack 10, the determination result of the temperature of the load application mechanism 20 including the temperature of the fluid, and the determination result of the voltage of the electric motor 40. It is sufficient to use at least one determination result of the temperature of the stack 10, the temperature of the load application mechanism 20 including the temperature of the fluid, and the voltage of the electric motor 40. When multiple determination results are used, the controller 30 may set the predetermined load value based on the number of positive determinations. Specifically, the greater the number of positive determinations, the higher the predetermined load value is set. As a result, for example, the target load value when the temperature of the stack 10 is higher than the predetermined temperature and the voltage of the electric motor 40 is higher than the target load value when the temperature of the stack 10 is higher than the predetermined temperature is set higher.

[0044] Furthermore, the load application mechanism 20 may include a self-locking reducer having an input section and an output section. A self-locking reducer cannot be operated from the output section by the load applied from the stack 10, but is operated by the driving force of the electric motor 40 input to the input section. If the load application mechanism 20 is a self-locking type, the holding position that holds the stack 10 is fixed when battery charging is completed or while the vehicle is stopped. Therefore, even if the load of the stack 10 fluctuates due to expansion and contraction of the stack 10, the load of the stack 10 can be maintained within a predetermined allowable range by setting a target load value that takes into account the factors of the fluctuation in advance, and therefore a self-locking load application mechanism 20 can be used.

[0045] A method for correcting the target load value of the compressive load applied to the stack 10 by the load applying mechanism 20 according to this embodiment will be described below. Fig. 3 is a flowchart showing a method for correcting the target load value of the compressive load by the load applying mechanism according to this embodiment.

[0046] In step S101, charging of the battery or running of the vehicle begins. In step S102, the first detection unit 11 and the second detection unit 12 detect the temperatures of the stack 10 and the load application mechanism 20. In step S103, the controller 30 determines whether the temperatures of the stack 10 and the load application mechanism 20 are lower than a predetermined temperature. If the temperatures of the stack 10 and the load application mechanism 20 are lower than the predetermined temperature, the controller 30 proceeds to step S104. If the temperatures of the stack 10 and the load application mechanism 20 are higher than the predetermined temperature, the controller 30 proceeds to step S105. In step S104, the controller 30 corrects the target load value of the compressive load of the load application mechanism 20 in an increasing direction. For example, the controller 30 corrects the target load value by adding a predetermined load value to the target load value when the temperatures of the stack 10 and the load application mechanism 20 are higher than the predetermined temperature.

[0047] In step S105, the controller 30 determines whether battery charging has finished or the vehicle has stopped. If battery charging has finished or the vehicle has stopped, the controller 30 proceeds to step S106. If battery charging has not finished or the vehicle has not stopped, the controller 30 returns to step S102 and repeats the subsequent steps. In step S106, the first detection unit 11 and the second detection unit 12 detect the temperatures of the laminate 10 and the load application mechanism 20. In step S107, the controller 30 determines whether the temperatures of the laminate 10 and the load application mechanism 20 are higher than a predetermined temperature. If the temperatures of the laminate 10 and the load application mechanism 20 are higher than the predetermined temperature, the controller 30 proceeds to step S108. If the temperatures of the laminate 10 and the load application mechanism 20 are lower than the predetermined temperature, the controller 30 proceeds to step S109. In step S108, the controller 30 corrects the target load value of the compressive load of the load application mechanism 20 in an increasing direction. For example, the controller 30 corrects the target load value by adding a predetermined load value to the target load value.

[0048] In step S109, the controller 30 determines whether the voltage of the load applying mechanism 20 is lower than a predetermined voltage. If the voltage of the load applying mechanism 20 is lower than the predetermined voltage, the controller 30 proceeds to step S110. If the voltage of the load applying mechanism 20 is higher than the predetermined voltage, the controller 30 proceeds to step S111. In step S110, the controller 30 corrects the target load value of the compressive load of the load applying mechanism 20 in an increasing direction. For example, the controller 30 corrects the target load value by adding a predetermined load value to the target load value.

[0049] In step S111, the controller 30 determines whether the operation frequency, operation time, or drive energy of the load applying mechanism during a predetermined period before the end of charging or the vehicle stop is equal to or greater than a predetermined value. If the operation frequency, operation time, or drive energy of the load applying mechanism is equal to or greater than a predetermined value, the controller 30 proceeds to step S112. If the operation frequency, operation time, or drive energy of the load applying mechanism is not equal to or greater than a predetermined value, the controller 30 proceeds to step S113. In step S112, the controller 30 corrects the target load value of the compressive load of the load applying mechanism 20 in an increasing direction. For example, the controller 30 corrects the target load value by adding a predetermined load value to the target load value. In step S113, the load applying mechanism 20 stops operating. Specifically, the load applying mechanism 20 adjusts the value of the compressive load to the target load value and then stops operating.

[0050] In step S114, the controller 30 determines whether battery recharging or vehicle running has started within a predetermined time after charging has ended or the vehicle has stopped. If battery recharging or vehicle running has started within the predetermined time after charging has ended or the vehicle has stopped, the controller 30 proceeds to step S115. If battery recharging or vehicle running has not started within the predetermined time after charging has ended or the vehicle has stopped, the controller 30 ends the control flow. In step S115, the controller 30 corrects the target load value in the opposite direction (decreasing direction) to the correction (increasing direction) made when charging ended or the vehicle was stopped. For example, the controller 30 corrects the target load value so that the target load value is lower than the target load value after correction in the increasing direction.

[0051] As described above, the retention mechanism according to this embodiment is a retention mechanism that compresses a battery stack in the stacking direction to maintain the surface pressure applied to the stack, and includes a load application unit that applies a compressive load to the stack, an electric motor that generates the driving force required to operate the load application unit, and a detection unit that detects a first detection value related to a characteristic of the stack and a second detection value related to a characteristic of the load application unit, the detection unit detects the first detection value and the second detection value when charging of the battery is completed or when the vehicle in which the battery is installed is stopped, and the load application unit corrects the target load value of the compressive load to be applied to the stack when operation of the load application unit is stopped, based on the first detection value and the second detection value when charging of the battery is completed or the vehicle is stopped. This allows the surface pressure applied to the battery to be appropriately maintained in accordance with changes in the characteristics of the member that applies the compressive load to the battery.

[0052] Furthermore, in the holding mechanism according to this embodiment, the detection unit detects the temperature of the stack as a first detection value and detects the temperature of the load application unit as a second detection value, and when the temperature of the stack and / or the load application unit is higher than a predetermined temperature at the end of charging the battery or when the vehicle is stopped, the load application unit corrects the target load value so as to increase the target load value compared to the target load value when the temperature of the stack and / or the load application unit is lower than the predetermined temperature. This makes it possible to appropriately maintain the surface pressure on the battery even when the temperature of the battery and the temperature of the member that applies a compressive load to the battery change.

[0053] Furthermore, in the holding mechanism according to this embodiment, the detection unit detects the voltage of the electric motor as the second detection value, and the load application unit corrects the target load value so that, when the voltage at the end of battery charging or when the vehicle is stopped is lower than a predetermined voltage, the target load value is increased by at least the predetermined load value compared to the target load value when the voltage is higher than the predetermined voltage. This makes it possible to appropriately maintain the surface pressure on the battery even when the voltage of the electric motor that operates the member that applies a compressive load to the battery changes.

[0054] In addition, in the holding mechanism according to this embodiment, the load application unit applies a compressive load to the stack by the pressure of the fluid, and the detection unit detects the temperature of the fluid as the temperature of the load application unit, so that the surface pressure applied to the battery can be appropriately maintained even if the temperature of the fluid used to apply the compressive load to the stack changes.

[0055] Furthermore, in the holding mechanism according to this embodiment, the load application section includes a self-locking reducer having an input section and an output section, and the self-locking reducer cannot be operated from the output section by the load applied from the stack, but is operated by the driving force of the electric motor input to the input section. As a result, when the self-locking reducer is included, the position that holds the battery is fixed when charging of the battery is completed or the vehicle is stopped, so that even if the battery load fluctuates due to expansion and contraction of the battery, the battery load can be maintained within an allowable range.

[0056] Furthermore, in the holding mechanism according to this embodiment, if the battery is recharged or the vehicle starts running within a predetermined time after the battery has finished charging or the vehicle has stopped, the load application unit corrects the target load value in the opposite direction to the correction of the target load value when the load application unit stopped operating. This prevents the surface pressure on the battery from becoming excessive and maintains the surface pressure on the battery within an allowable range, even if the battery is recharged or the vehicle starts running after the load to be applied to the battery was set high assuming a long period of unused storage.

[0057] Furthermore, in the holding mechanism according to this embodiment, the detection unit detects, as a second detection value, the operation frequency, operation time, or amount of drive energy of the load application unit during a predetermined period before the battery charging is completed or the vehicle is stopped, and the load application unit determines that the temperature of the load application unit at the time of the battery charging completion or the vehicle stopping is higher than a predetermined temperature if the operation frequency, operation time, or amount of drive energy is equal to or greater than a predetermined value. This makes it possible to maintain the surface pressure on the battery within an allowable range even if the temperature rises by the time of the battery charging completion or the vehicle stopping, causing the load applied to the battery to decrease after the operation of the holding mechanism is stopped.

[0058] Furthermore, in the holding mechanism according to this embodiment, when the temperature of the stack and the load applying unit is lower than a predetermined temperature when charging of the battery or when the vehicle starts running, the load applying unit corrects the target load value so that the target load value is higher than the target load value when the temperature of the stack and the load applying unit is higher than the predetermined temperature. As a result, the deviation between the actual load value applied to the battery and the target load value becomes larger, so the command value for the drive torque of the electric motor can be increased to improve the responsiveness of the load applying unit, thereby maintaining the surface pressure on the battery within an allowable range.

[0059] In addition, in the holding mechanism according to this embodiment, the battery is an all-solid-state battery, which makes it possible to appropriately maintain surface pressure on the all-solid-state battery.

[0060] It should be noted that the above-described embodiments have been described to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each element disclosed in the above-described embodiments is intended to include all design modifications and equivalents that fall within the technical scope of the present invention. [Explanation of symbols]

[0061] 1...Holding mechanism 10...Laminate 11...First detection unit 12...Second detection unit 20...Load application mechanism 30...Controller 40...Electric motor

Claims

1. A holding mechanism that compresses a battery stack in a stacking direction to hold a surface pressure applied to the stack, a load application section that applies a compressive load to the laminated body; an electric motor that generates a driving force necessary to operate the load application unit; a detection unit that detects a first detection value related to a characteristic of the stack and a second detection value related to a characteristic of the load application unit, The detection unit detecting the first detection value and the second detection value when charging of the battery is completed or when a vehicle in which the battery is mounted is stopped; The load application portion is A holding mechanism that corrects the target load value of the compressive load to be applied to the stack when operation of the load application unit is stopped, in accordance with the first detection value and the second detection value when charging of the battery is completed or the vehicle is stopped.

2. 2. The retention mechanism of claim 1, the detection unit detects a temperature of the stack as the first detection value and detects a temperature of the load application unit as the second detection value; The load application unit has a holding mechanism that corrects the target load value so that, when the temperature of the stack and / or the load application unit is higher than a predetermined temperature when charging of the battery is completed or the vehicle is stopped, the target load value is increased beyond the target load value when the temperature of the stack and / or the load application unit is lower than the predetermined temperature.

3. 3. The holding mechanism according to claim 1 or 2, the detection unit detects a voltage of the electric motor as the second detection value, The load application unit is a holding mechanism that corrects the target load value so that, when the voltage at the end of charging of the battery or when the vehicle is stopped is lower than a predetermined voltage, the target load value is increased by a predetermined load value or more compared to the target load value when the voltage is higher than the predetermined voltage.

4. 3. The retention mechanism according to claim 2, the load application unit applies the compressive load to the stacked body by a fluid pressure, The detection unit detects the temperature of the fluid as the temperature of the load application unit.

5. 3. The holding mechanism according to claim 1 or 2, the load application unit includes a self-locking reducer having an input unit and an output unit, The self-locking reducer is a holding mechanism that cannot be operated from the output section by the load applied from the stack, and is operated by the driving force of the electric motor input to the input section.

6. 3. The holding mechanism according to claim 1 or 2, The load application unit has a holding mechanism that corrects the target load value in the opposite direction to the correction of the target load value when the load application unit stops operating, when the battery is recharged or the vehicle starts running within a predetermined time after charging of the battery is completed or the vehicle is stopped.

7. 3. The retention mechanism according to claim 2, the detection unit detects, as the second detection value, an operation frequency, an operation time, or an amount of drive energy of the load application unit during a predetermined period before charging of the battery is completed or before the vehicle is stopped; The load application portion is A holding mechanism that determines that the temperature of the load-applying part when charging of the battery is completed or when the vehicle is stopped is higher than the predetermined temperature when the operation frequency, the operation time, or the amount of driving energy is equal to or greater than a predetermined value.

8. 3. The retention mechanism according to claim 2, The load application unit has a holding mechanism that corrects the target load value so that, when the temperature of the stack and the load application unit is lower than the predetermined temperature when charging of the battery or when the vehicle starts to run, the target load value is increased beyond the target load value when the temperature of the stack and the load application unit is higher than the predetermined temperature.

9. 3. The holding mechanism according to claim 1 or 2, The battery is a solid-state battery.

Images