All-solid-state battery structure

Abstract

To provide an all-solid-state battery structure that can be miniaturized. [Solution] The all-solid-state battery structure includes a surface pressure holding mechanism that applies surface pressure to the stacked cells of the all-solid-state battery housed in a module. The surface pressure holding mechanism has an operating part and a holding part. The operating part includes a motor, a reduction gear, a screw shaft, a first support part that meshes with the screw surface of the screw shaft, a second support part that supports the rod portion of the screw shaft, a cell load transmission part that transmits load to the stacked cells, and a third support part that supports the cell load transmission part. The holding part includes a hydraulic piston, a hydraulic cylinder including a hydraulic chamber, and a reserve tank. The hydraulic piston, the cell load transmission part, and the first support part are integrally formed. The screw shaft and the cell load transmission part pass through the hydraulic cylinder of the holding part.

Description

Technical Field

[0001] The present invention relates to an all-solid-state battery structure.

Background Art

[0002] Patent Document 1 discloses a battery system provided with a soft actuator whose volume changes by applying voltage and / or current to at least one end of both ends in the stacking direction of a stacked battery in which a plurality of single cells that expand and contract are stacked.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] When the actuator operates with hydraulic pressure, high hydraulic pressure is required, and a hydraulic pump, hydraulic piping, a reservoir tank, and oil are necessary, so there is a possibility that the battery system will become larger and heavier.

[0005] The present invention has been made in view of such circumstances, and an object thereof is to provide an all-solid-state battery structure that can be miniaturized.

Means for Solving the Problems

[0006] A solid-state battery structure according to one aspect of the present invention includes a surface pressure holding mechanism for applying surface pressure to stacked cells of a solid-state battery housed in a module. The surface pressure holding mechanism has an operating part and a holding part. The operating part includes a motor, a reduction gear, a screw shaft, a first support part that engages with the screw surface of the screw shaft, a second support part that supports the rod portion of the screw shaft, a cell load transmission part that transmits load to the stacked cells, and a third support part that supports the cell load transmission part. The holding part includes a hydraulic piston, a hydraulic cylinder including a hydraulic chamber, and a reserve tank. The hydraulic piston, the cell load transmission part, and the first support part are integrally formed. The screw shaft and the cell load transmission part pass through the hydraulic cylinder of the holding part. [Effects of the Invention]

[0007] According to one aspect of the present invention, a miniaturized all-solid-state battery structure can be provided. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 is a schematic diagram showing an example of the overall configuration of an all-solid-state battery according to Embodiment 1 of the present invention. [Figure 2A] Figure 2A is a plan view showing an example of the configuration within a module according to Embodiment 1 of the present invention. [Figure 2B] Figure 2B is a cross-sectional view showing an example of the configuration within a module according to Embodiment 1 of the present invention. [Figure 2C] Figure 2C is a cross-sectional view showing an example of the configuration within a module according to Embodiment 1 of the present invention. [Figure 2D] Figure 2D is a cross-sectional view showing an example of the configuration within a module according to Embodiment 1 of the present invention. [Figure 3] Figure 3 shows an example of piping connection between the oil chamber and the reserve tank. [Figure 4] Figure 4 is a cross-sectional view illustrating the hydraulic piston, screw support section, and cell load transmission section. [Figure 5] Figure 5 is a cross-sectional view illustrating a hydraulic cylinder and a rod support section. [Figure 6] FIG. 6 is a cross-sectional view showing a configuration example of a module according to Embodiment 2 of the present invention. [Figure 7A] FIG. 7A is a cross-sectional view showing a configuration example of a module according to Embodiment 3 of the present invention. [Figure 7B] FIG. 7B is a cross-sectional view showing a configuration example of a module according to Embodiment 3 of the present invention. [Figure 7C] FIG. 7C is a cross-sectional view showing a configuration example of a module according to Embodiment 3 of the present invention. [Figure 8A] FIG. 8A is a cross-sectional view showing a configuration example of a module according to Embodiment 4 of the present invention. [Figure 8B] FIG. 8B is a cross-sectional view showing a configuration example of a module according to Embodiment 4 of the present invention. [Figure 8C] FIG. 8C is a cross-sectional view showing a configuration example of a module according to Embodiment 4 of the present invention. [Figure 9A] FIG. 9A is a cross-sectional view showing a configuration example of a module according to Embodiment 5 of the present invention. [Figure 9B] FIG. 9B is a cross-sectional view showing a configuration example of a module according to Embodiment 5 of the present invention. [Figure 10A] FIG. 10A is a cross-sectional view showing a configuration example of a module according to Embodiment 6 of the present invention. [Figure 10B] FIG. 10B is a cross-sectional view showing a configuration example of a module according to Embodiment 6 of the present invention. [Figure 11] FIG. 11 is a cross-sectional view showing a configuration example of a module according to Embodiment 7 of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the description of the drawings referred to below, the same or similar parts are denoted by the same or similar reference numerals. However, it should be noted that the drawings are schematic, and the ratios of the thicknesses and lengths of each part are different from the actual ones.

[0010] <Embodiment 1> (Configuration example) FIG. 1 is a schematic diagram showing an overall configuration example of a all-solid-state battery 100 (an example of the “all-solid-state battery structure” of the present invention) according to Embodiment 1 of the present invention. As shown in FIG. 1, the all-solid-state battery 100 includes a plurality of modules 1. Each of the plurality of modules 1 has a housing 2, a stacked cell 3 of all-solid-state batteries stored in the housing 2, and a surface pressure holding mechanism 4 that applies surface pressure to the stacked cell 3. The surface pressure holding mechanism 4 has an operating part 5 and a hydraulic pressure holding part 7 (an example of the “holding part” of the present invention). At least a part of the operating part 5 and at least a part of the hydraulic pressure holding part 7 are stored in the housing 2.

[0011] FIG. 2A is a plan view showing a configuration example inside the module 1 according to Embodiment 1 of the present invention. FIGS. 2B to 2D are cross-sectional views showing a configuration example inside the module 1 according to Embodiment 1 of the present invention. FIG. 2B shows a cross-section obtained by cutting FIG. 2A along the line X-X'. FIGS. 2C and 2D show cross-sections obtained by cutting FIG. 2A along the line Y-Y'. FIG. 2B shows the time of maximum shrinkage of the stacked cell 3, FIG. 2D shows the time of maximum expansion of the stacked cell 3, and FIG. 2C shows the intermediate time between the maximum shrinkage and the maximum expansion of the stacked cell 3.

[0012] As shown in FIGS. 2A to 2D, the module 1 has a rectangular parallelepiped housing 2, and the stacked cell 3 is arranged at the upper part inside the housing 2. In addition, inside the housing 2, a pair of support plates 41a and 41b and a compression spring 42 arranged between the support plates 41a and 41b are provided. One end of the compression spring 42 is attached to the support plate 41a, and the other end of the compression spring 42 is attached to the support plate 41b. The stacked cell 3 is installed on the support plate 41a. The operating part 5 and the hydraulic pressure holding part 7 are arranged in the lower space of the housing 2 (the space below the support plate 41a).

[0013] The operating unit 5 includes a screw shaft 51, a reduction gear 53, a motor 54, a screw support part 56 (an example of the "first support part" of the present invention) that engages with the screw surface 511 of the screw shaft 51, a rod support part 55 (an example of the "second support part" of the present invention) that supports the rod of the screw shaft 51, a cell load transmission part 52 that transmits load to the laminated cell 3, and a rod support part 57 (an example of the "third support part" of the present invention) that supports the transmission rod 522 of the cell load transmission part 52. The screw shaft 51 is a male screw, and the screw support part 56 is a female screw.

[0014] For example, the rod of the screw shaft 51 is manually supported in the vertical direction by a rod support portion 55. An oil seal 551 may be provided between the rod portion of the screw shaft 51 and the rod support portion 55 to prevent oil leakage from the high-pressure side hydraulic chamber 72A to the outside of the hydraulic cylinder 71, as described later. The cell load transmission portion 52 includes a disc-shaped transmission plate 521 and a transmission rod 522 fixed to the surface of the transmission plate 521 opposite to the surface that contacts the support plate 41b. The transmission rod 522 is slidably supported in the vertical direction by a rod support portion 57. An oil seal 571 may be provided between the transmission rod 522 and the rod support portion 57 to prevent oil leakage from the low-pressure side hydraulic chamber 72B to the outside of the hydraulic cylinder 71, as described later.

[0015] The hydraulic holding unit 7 includes a hydraulic cylinder 71, a reserve tank 73, and a hydraulic piston 74. For example, the hydraulic cylinder 71 and the hydraulic piston 74 are of the double-acting single-rod type. The hydraulic piston 74 is disc-shaped, and a transmission rod 522 is fixed to its upper surface. The hydraulic piston 74 is located inside the hydraulic cylinder 71 and divides the oil chamber 72 inside the hydraulic cylinder 71 into two chambers arranged vertically. Of the oil chambers 72, the oil chamber below the hydraulic piston 74 is the high-pressure hydraulic chamber 72A, and the oil chamber above the hydraulic piston 74 is the low-pressure hydraulic chamber 72B.

[0016] Oil is stored in the oil chamber 72 as the working fluid. The reserve tank 73 is an oil chamber that stores oil supplied to or recovered from the oil chamber 72. Piping for oil is provided between the high-pressure hydraulic chamber 72A and the reserve tank 73. The black arrows in Figures 2A and 2B illustrate how oil is supplied from the reserve tank 73 to the high-pressure hydraulic chamber 72A through the piping by the pushing action of the hydraulic piston 74. Piping for oil is also provided between the low-pressure hydraulic chamber 72B and the reserve tank 73. The white arrows in Figures 2A and 2B illustrate how oil is supplied from the low-pressure hydraulic chamber 72B to the reserve tank 73 through the piping by the pushing action of the hydraulic piston 74.

[0017] Figure 3 shows an example of piping connection between the oil chamber 72 and the reserve tank 73. Note that the screw shaft 51 and other components are omitted from the illustration in Figure 3. As shown in Figure 3, the low-pressure side hydraulic chamber 72B and the reserve tank 73 within the hydraulic cylinder 71 are connected by piping 76. In addition, parallel piping 77 and 78 are provided connecting the high-pressure side hydraulic chamber 72A and the low-pressure side hydraulic chamber 72B. A check valve 771 is provided in piping 77, and an on-off valve 781 is provided in piping 78. For example, when the on-off valve 781 is open, it is possible to supply oil from at least one of the low-pressure side hydraulic chamber 72B and the reserve tank 73 to the high-pressure side hydraulic chamber 72A through piping 78. By controlling the opening and closing of the on-off valve 781, it is possible to adjust the oil supply between the high-pressure side hydraulic chamber 72A, the low-pressure side hydraulic chamber 72B, and the reserve tank 73.

[0018] Figure 4 is a cross-sectional view illustrating the hydraulic piston 74, the screw support section 56, and the cell load transmission section 52. The hydraulic piston 74, the cell load transmission section 52 (transmission plate 521 and transmission rod 522), and the screw support section 56 shown in Figure 4 are integrally formed. Any method can be used to integrally form these components, such as forming them by injecting molten metal into a mold or by cutting a metal block.

[0019] Figure 5 is a cross-sectional view illustrating a hydraulic cylinder 71 and rod support parts 55 and 57. The hydraulic cylinder 71 and rod support parts 55 and 57 shown in Figure 5 are integrally formed. Any method can be used to integrally form them, such as forming them by injecting molten metal into a mold or by cutting a metal block.

[0020] Furthermore, the hole diameter of the rod support portion 55 is smaller than the hole diameter of the rod support portion 57. As a result, the hydraulic piston area on the high-pressure side hydraulic chamber 72A is larger than the hydraulic piston area on the low-pressure side hydraulic chamber 72B, which reduces the hydraulic pressure in the high-pressure side hydraulic chamber 72A when maintaining cell surface pressure and suppresses an increase in oil leakage from the high-pressure side hydraulic chamber 72A.

[0021] (Example of operation) In module 1 shown in Figures 1 to 2D, when the operating unit 5 is operated, the on-off valve 781 (see Figure 3) is opened to allow the supply of oil between the high-pressure hydraulic chamber 72A, the low-pressure hydraulic chamber 72B, and the reserve tank 73. In this state, the motor 54 is driven to rotate the screw shaft 51 via the reduction gear 53. As a result, the hydraulic piston 74 connected to the screw shaft 51 via the screw support unit 56 and the cell load transmission unit 52 integrally formed with the hydraulic piston 74 move up and down, transmitting the load to the support plate 41b.

[0022] During charging and discharging, the operation of the operating unit 5 is stopped. The on / off valve 781 is closed, and the cell surface pressure is maintained by the hydraulic pressure of the high-pressure side hydraulic chamber 72A (i.e., the holding force by the hydraulic holding unit 7).

[0023] When charging begins after charging / discharging has stopped, cell expansion occurs, increasing the cell surface pressure. During charging, the holding force by the hydraulic holding unit 7 increases and reaches a predetermined value (predetermined value 1). At this point, the on / off valve 781 is opened to release oil from the high-pressure side hydraulic chamber 72A to the reserve tank 73, and the actuation unit 5 is activated to move the hydraulic piston 74 downward, reducing the holding force by the hydraulic holding unit 7. As a result, the expanded stacked cells 3 are held at an appropriate surface pressure (low surface pressure).

[0024] Furthermore, when charging and discharging stops and then discharge begins, cell contraction occurs, causing the cell surface pressure to decrease. During discharge, the holding force by the hydraulic holding unit 7 decreases and reaches a predetermined value (predetermined value 2). At this point, the on / off valve 781 is opened to supply oil from the reserve tank 73 to the high-pressure side hydraulic chamber 72A, and the actuation unit 5 is activated to move the hydraulic piston 74 upward, thereby increasing the holding force by the hydraulic holding unit 7. As a result, the contracted laminated cells 3 are held with appropriate surface pressure (high surface pressure).

[0025] (Effects of Embodiment 1) (1) As described above, the all-solid-state battery 100 according to Embodiment 1 of the present invention comprises a module 1 that houses stacked cells 3 of the all-solid-state battery, and a surface pressure holding mechanism 4 that applies surface pressure to the stacked cells 3 housed in the module 1. The surface pressure holding mechanism 4 has an operating part 5 and a hydraulic holding part 7. The operating part 5 includes a motor 54, a reduction gear 53, a screw shaft 51, a screw support part 56 that engages with the screw surface 511 of the screw shaft 51, a rod support part 55 that supports the rod portion of the screw shaft 51, a cell load transmission part 52 that transmits load to the stacked cells 3, and a rod support part 57 that supports the cell load transmission part 52. The hydraulic holding part 7 includes a hydraulic piston 74, a hydraulic cylinder 71 including a hydraulic chamber, and a reserve tank 73. The hydraulic piston 74, the cell load transmission part 52, and the screw support part 56 are integrally formed. The screw shaft 51 and the cell load transmission part 52 pass through the hydraulic cylinder 71 of the hydraulic holding part 7.

[0026] As a result, the all-solid-state battery 100 has the following effect (1). (1) Since the cell load transmission unit 52 and rod support unit 57 included in the operating unit 5 and the hydraulic piston 74 included in the hydraulic holding unit 7 are integrally formed, the surface pressure holding mechanism 4 can be made smaller and lighter. In addition, since the screw shaft 51 and the transmission rod 522 of the cell load transmission unit 52 pass through the oil chamber 72 of the hydraulic holding unit 7, the oil in the oil chamber 72 can be used to lubricate the sliding surface of the screw shaft 51.

[0027] Furthermore, in addition to the above effect (1), the all-solid-state battery 100 may have, for example, the following effects (1-1) to (1-5). (1-1) By using a highly rigid hydraulic cylinder 71 that can withstand high hydraulic pressure as a support member for the cell load transmission unit 52, it is possible to prevent the cell load transmission unit 52 from tipping over when it strokes in the extension direction. The surface pressure holding mechanism 4 of the laminated cell 3 needs to be able to handle both large loads and large strokes, and generate surface pressure evenly on the cell surface. Therefore, when the laminated cell 3 contracts and the cell load transmission unit 52 strokes in the extension direction, if a load in the tilting direction is applied to the cell load transmission unit 52 due to the tilting of the cell surface, the frictional resistance of each sliding part of the operating unit 5 increases, which may increase the operating energy or decrease the operating energy and thus the holding force. However, this possibility can be reduced or avoided.

[0028] (1-2) By constantly applying hydraulic pressure to the screw sliding surface integrated with the hydraulic holding part 7, even when the operating part 5 is stopped, oil film breakdown is prevented, and increased frictional resistance of the sliding part due to oil film breakdown, as well as seizure and sticking, can be avoided. The surface pressure holding mechanism 4 of the laminated cell 3 is constantly subjected to cell surface pressure, and when the vehicle is stopped, it is subjected to high loads for a long period of time with lubrication stopped, and furthermore, when the vehicle is running, it is also subjected to vibration input, so the sliding surface of the screw shaft 51 of the operating part 5 may be prone to oil film breakdown, but this possibility can be reduced or avoided.

[0029] (1-3) The lubricating oil storage case for the screw sliding surface of the operating part 5 can be integrated with the hydraulic holding part 7, making it possible to add a hydraulic holding function while suppressing an increase in size and weight.

[0030] (1-4) Since the oil chamber 72 and the screw sliding surface gap between the screw support 56 and the screw shaft 51 are in communication, it is possible to supply oil from the oil chamber 72 to the screw sliding surface gap for lubrication.

[0031] (1-5) Since the thrust direction of the screw shaft 51 can also be supported on the side of the hydraulic piston 74, it is possible to prevent the screw shaft 51 from tipping over, prevent a decrease in the operating efficiency of the screw shaft 51, and avoid a decrease in the sealing performance of the rod portion of the screw shaft 51.

[0032] The all-solid-state battery 100 may have the configuration and effects described in (2) to (3-4) below, for example. (2) Rod support sections 55 and 57 are integrally formed on the hydraulic cylinder 71. This allows the hydraulic cylinder 71 to bear the support functions of the screw shaft 51 and the cell load transmission section 52, making it possible to miniaturize and lighten the surface pressure holding mechanism 4. In addition, since the hydraulic cylinder 71 is thick to withstand high hydraulic pressure, support rigidity can be ensured by having the support function taken on by the thick section.

[0033] (3) The rod support portion 55 has an oil seal 551 between it and the screw shaft 51. The hydraulic pressure acting on the oil seal 551 may be higher when the screw shaft 51 is stopped than when it is rotating. This reduces the frictional resistance of the oil seal 551 as the hydraulic pressure acting on the oil seal 551 of the screw shaft 51 decreases during the rotation of the screw shaft 51, thereby improving the operating efficiency. Also, when the hydraulic pressure is maintained, the hydraulic pressure is high, but the screw shaft 51 is stopped rotating and the sealing performance of the oil seal 551 is good, so it is possible to suppress oil leakage.

[0034] (3-1) The rod support portion 57 has an oil seal 571 between it and the transmission rod 522. The hydraulic pressure acting on the oil seal 551 of the rod support portion 55 may be higher than the hydraulic pressure acting on the oil seal 571 of the rod support portion 57. In this case, since the hydraulic pressure acting on the oil seal 571 of the rod support portion 57 is low, it is possible to suppress oil leakage. Also, even if the hydraulic pressure acting on the oil seal 551 of the rod support portion 55 is high, even if oil leaks from the hydraulic cylinder 71 through the oil seal 551, the destination of the leaked oil is a part that communicates with the reduction gear chamber of the operating portion 5 (for example, see the reduction gear housing 531 shown in Figure 7C described later), so the oil will not leak to the outside.

[0035] (3-2) The hydraulic pressure applied to the rod support section 57 is low when the hydraulic piston 74 rises. When the hydraulic piston 74 rises (i.e., when the stacked cells 3 contract), it is necessary to operate the surface pressure holding mechanism 4 against the surface pressure of the cells, which increases the operating energy. However, by reducing the hydraulic pressure in the rod support section 57, the seal tightening force can be reduced, which reduces the friction of the oil seal 571 during operation and makes it possible to reduce the operating energy.

[0036] (3-3) The hydraulic pressure applied to the rod support section 57 becomes high pressure when the hydraulic piston 74 is descending. Although the increased hydraulic pressure increases the sealing tension of the rod support section 57, the surface pressure holding mechanism 4 can be operated using the cell surface pressure, so it is possible to suppress the increase in operating energy.

[0037] (3-4) The hydraulic pressure applied to the rod support section 57 becomes high pressure when the hydraulic piston 74 is stopped. The increased hydraulic pressure increases the sealing tension of the rod support section 57, which increases the rotational friction torque of the screw shaft 51 that is screwed onto the transmission rod 522. This makes it possible to reduce the holding energy of the surface pressure holding mechanism 4.

[0038] <Embodiment 2> Figure 6 is a cross-sectional view showing an example configuration of module 1A according to Embodiment 2 of the present invention. As shown in Figure 6, in the all-solid-state battery 100, the inside of the hydraulic cylinder 71 is divided into two oil chambers by a hydraulic piston 74, one oil chamber is designated as the hydraulic chamber 721, and the other oil chamber is designated as the reserve tank 722, and the hydraulic chamber 721 and the reserve tank 722 may be connected by an oil passage. Examples of oil passages include a first oil passage 523, a second oil passage 741, and a third oil passage 742. The first oil passage 523 penetrates the side surface of the transmission rod 522 and connects the inside of the transmission rod 522 to the reserve tank 722. The second oil passage 741 is the screw engagement surface between the screw shaft 51 and the hydraulic cylinder 71. The third oil passage 742 is a through hole that penetrates the hydraulic cylinder 71 in the thickness direction. The third oil passage 742 may include the check valve 771 and the on / off valve 781 shown in Figure 3. According to this, a reserve tank can be formed within the hydraulic cylinder 71, making it possible to miniaturize the surface pressure holding mechanism 4. Furthermore, as shown in Figure 7A and other figures described later, the inside of the transmission rod 522 can also be made part of the reserve tank, allowing for further miniaturization of the surface pressure holding mechanism 4.

[0039] As shown in Figure 6, when a hydraulic chamber 721 that holds the cell load and a reserve tank 722 that stores oil supplied to or recovered from the hydraulic chamber 721 are arranged within the hydraulic cylinder 71, the hydraulic chamber 721 is positioned further away from the stacked cell 3 than the reserve tank 722. This reduces the amount of heat absorbed by the oil in the hydraulic chamber 721 from the stacked cell 3, which overheats during charging and discharging. This makes it possible to suppress the temperature rise in the hydraulic chamber 721 and suppress the increase in oil leakage due to a decrease in the viscosity of the oil in the hydraulic chamber 721.

[0040] <Embodiment 3> Figures 7A to 7C are cross-sectional views showing an example configuration of module 1B according to Embodiment 3 of the present invention. Figure 7A shows the stacked cell 3 at its maximum contraction, Figure 7B shows the stacked cell 3 at its maximum expansion, and Figure 7C shows the stacked cell 3 at an intermediate position between its maximum contraction and maximum expansion. As shown in Figures 7A to 7C, in the all-solid-state battery 100, the inside of the transmission rod 522 may be used as an oil chamber, for example, a reserve tank. By storing oil inside the transmission rod 522 due to the decrease in the volume of the oil chamber when the transmission rod 522 is retracted into the oil chamber 72, it becomes unnecessary to provide a reserve tank outside the hydraulic pressure holding unit 7. Alternatively, even if a reserve tank is provided outside the hydraulic pressure holding unit 7, its capacity can be reduced. This makes it possible to miniaturize the surface pressure holding mechanism 4.

[0041] For example, by making the volume of the oil chamber inside the rod of the hydraulic piston 74 (e.g., the transmission rod 522) variable in response to the change in the amount of oil in the oil chamber 72 when the hydraulic piston 74 is operating, the total volume of the oil chamber inside the oil chamber 72 and the transmission rod 522 becomes constant or nearly constant. When the hydraulic cylinder 71 and hydraulic piston 74 constitute two oil chambers, and the transmission rod 522 penetrates the bottom surface of one of the oil chambers, the change in the amount of oil in the two oil chambers differs by the volume of the transmission rod 522 that enters the hydraulic cylinder 71 when the hydraulic piston 74 is operating. For this reason, a reserve tank is needed to hold the different amounts of oil outside the oil chambers, but by providing a variable-volume oil chamber inside the transmission rod 522 that can maintain a constant total volume, a closed hydraulic circuit can be formed, and the intrusion of air from the outside can be prevented. For example, when the volume inside the oil chamber 72 decreases, oil is allowed to flow from the hydraulic chamber 721 into the transmission rod 522. When the volume inside the oil chamber 72 increases, oil is released from inside the transmission rod 522 into the hydraulic chamber 721.

[0042] When the actuation unit 5 is activated in response to the expansion and contraction of the laminated cell 3, the volume of the oil chamber 72 changes. During the expansion and contraction of the laminated cell 3, the screw sliding part of the actuation unit 5 slides under load, requiring lubrication by oil. As the volume of the oil chamber 72 changes, oil flows from the oil chamber 72 or the transmission rod 522 into the screw sliding part, thus maintaining good lubrication.

[0043] The screw engagement portion between the screw shaft 51 and the rod support portion 57 may be formed so as to connect the hydraulic chamber 721 and the inside of the transmission rod 522 (for example, the reserve tank). That is, the inside of the hydraulic chamber 721 and the inside of the transmission rod 522 may be connected through the gap in the screw engagement portion between the screw surface 511 of the screw shaft 51 and the screw support portion 56. Since the gap in the screw engagement portion can be used as an oil passage, there is no need to form a dedicated oil passage between the hydraulic chamber 721 and the inside of the transmission rod 522, and the surface pressure holding mechanism 4 can be miniaturized. In addition, since the hydraulic pressure of the hydraulic chamber 721 can be used to supply oil to the screw engagement portion at high pressure, it is possible to ensure more reliable oil supply to the screw engagement portion and prevent oil film breakdown.

[0044] The length of the engagement portion on the threaded surface of the screw shaft 51 is shorter when the laminated cell 3 is contracted than when the laminated cell 3 is expanded. For example, regarding the length of the thread engagement portion between the threaded surface 511 of the screw shaft 51 and the screw support portion 56, if we let L1 be the length of the thread engagement portion when the laminated cell 3 is at its maximum contraction and L2 be the length of the thread engagement portion when the laminated cell 3 is at its maximum expansion, then L1 <L2となっていてもよい。

[0045] When the cell charge level is low, the resistance to oil movement from the hydraulic chamber 721, which is the hydraulic retention chamber, via the screw sliding surface is small. Therefore, in response to the expansion of the stacked cells 3 during charging, it is possible to discharge oil from the hydraulic chamber 721 to the reserve tank and contract the hydraulic chamber 721. The screw sliding surface refers to, for example, the screw engagement portion between the screw surface 511 of the screw shaft 51 and the screw support portion 56. Furthermore, when the vehicle is stopped for a long period of time in a fully charged state, the oil passage resistance via the screw sliding surface increases, which suppresses oil leakage and makes it possible to maintain cell surface pressure even after being left unused for a long period of time.

[0046] At least a portion of the threaded surface 511 of the screw shaft 51 is exposed to the oil chamber 72. This ensures that the oil in the oil chamber 72 adheres reliably to the sliding surface of the operating part 5. Furthermore, during operation, it is possible to supply oil to the gap in the sliding surface of the operating part 5 that communicates with the oil chamber 72. Moreover, the gap in the sliding surface can be used as an oil passage for the oil chamber 72, eliminating the need for a dedicated oil passage.

[0047] As shown in Figure 7A, when the hydraulic piston 74 rises, the reserve tank 722 is pressurized, and oil flows into the screw sliding surface. Also, as shown in Figure 7B, when the hydraulic piston 74 descends, the hydraulic chamber 721 is pressurized, and oil flows into the screw sliding surface. The amount of oil supplied to the screw sliding surface is greater when the hydraulic piston 74 is in operation (i.e., when the screw shaft 51 is rotating) than when the hydraulic piston 74 is stopped (i.e., when the screw shaft 51 is stopped). By utilizing the fact that the hydraulic pressure in the oil chamber 72 decreases during operation and increases during holding, it is possible to prevent the oil film from breaking down on the screw sliding surface during operation and reduce frictional resistance. This also prevents seizing and sticking of the screw sliding surface.

[0048] Furthermore, the hydraulic chamber 721 and the reserve tank 722 may be connected by piping, and a shut-off valve 75 may be provided in this piping. By opening the shut-off valve 75, it may be possible to allow oil to flow between the hydraulic chamber 721 and the reserve tank 722 via the piping.

[0049] As shown in Figures 7A to 7C, the hydraulic chamber 721 and the oil chamber (e.g., reserve tank) inside the rod (e.g., transmission rod 522) of the hydraulic piston 74 are sealed inside module 1B. This prevents oil leakage to the outside of module 1B. Furthermore, since the oil in the hydraulic holding section 7 can be isolated from the hydraulic operating section 5, the oils in the operating section 5 and the hydraulic holding section 7 can be made different. This makes it possible to increase the oil viscosity in the hydraulic holding section 7 to reduce oil leakage during holding, prevent oil film breakdown on screw sliding surfaces, and reduce friction loss in the operating section 5.

[0050] As shown in Figure 7C, module 1B may include a reducer housing 531 that houses the reducer 53. For example, the reducer housing 531 is fixed to the hydraulic cylinder 71. The inside of the reducer housing 531 is in communication with the inside of the hydraulic cylinder 71. With this configuration, even if oil leaks out of the hydraulic chamber 721 from between the screw shaft 51 and the rod support portion 55, the oil will leak into the inside of the reducer housing 531, and the oil will be sealed by the reducer housing 531, so the oil will not leak out of module 1B. In addition, the oil inside the reducer housing 531 can be used to lubricate the reducer 53.

[0051] <Embodiment 4> Figures 8A to 8C are cross-sectional views showing an example configuration of module 1C according to Embodiment 4 of the present invention. Figure 8A shows the laminated cell 3 at its maximum contraction, Figure 8C shows the laminated cell 3 at its maximum expansion, and Figure 8B shows the laminated cell 3 at an intermediate state between its maximum contraction and maximum expansion. In Embodiment 4, the oil chamber inside the hydraulic piston 74 or inside the rod of the hydraulic piston 74 (for example, the transmission rod 522) is used as an accumulator. For example, the inside of the transmission rod 522 or the inside of the screw shaft 51 may be used as a volume-variable oil chamber and serve as an accumulator. Examples of accumulator configurations include a combination of a metal compression spring 45 and a piston, or a gas spring 46.

[0052] According to this, the hydraulic pressure inside the rod (for example, inside the transmission rod 522 or the screw shaft 51) can be increased, so the hydraulic pressure inside the rod can be used when returning oil to the high-pressure side hydraulic chamber 72A of the hydraulic holding part 7. This prevents the high-pressure side hydraulic chamber 72A from becoming negative pressure and generating air. In addition, the pressure accumulated inside the rod can be used as a spring to maintain the cell surface pressure. This makes it possible to reduce the holding force of the hydraulic holding part 7 and the operating part 5.

[0053] <Embodiment 5> Figures 9A and 9B are cross-sectional views showing an example configuration of module 1D according to Embodiment 5 of the present invention. Figure 9A shows the laminated cell 3 at its maximum contraction, and Figure 9B shows the laminated cell 3 at its maximum expansion. As shown in Figures 9A and 9B, in this example, the hydraulic piston 74 is attached to the support plate 41b while maintaining its outer diameter at a constant value. Inside the hydraulic piston 74, there are a plurality of oil chambers divided along the vertical direction in which the hydraulic piston 74 operates. Each oil chamber of the hydraulic piston 74 is a volume-variable oil chamber and acts as an accumulator. Furthermore, each oil chamber of the hydraulic piston 74 and the hydraulic chamber 721 are in communication through an oil passage or a gap in the screw engagement portion. This allows the volume of the oil chamber (e.g., reserve tank) inside the hydraulic piston 74 to be increased, making it possible to miniaturize the surface pressure holding mechanism 4.

[0054] <Embodiment 6> Figures 10A and 10B are cross-sectional views showing an example configuration of module 1E according to Embodiment 6 of the present invention. Figure 10A shows the laminated cell 3 at its maximum contraction, and Figure 10B shows the laminated cell 3 at its maximum expansion. The module 1 shown in Figures 10A and 10B includes, for example, a compression spring 42 installed between a hydraulic piston 74 and a support plate 41, and is equipped with a passive surface pressure holding mechanism 4. As a result, when the laminated cell 3 is contracted, the cell surface pressure holding force is small and the pressure inside the hydraulic chamber 721 is low, so even when the resistance from the oil leakage path is small, there is little oil leakage, and thus it is possible to suppress the reduction in holding force due to oil leakage.

[0055] Module 1 includes a hydraulic pressure generating unit 44 that supplies hydraulic pressure to the hydraulic chamber 721. The hydraulic pressure generating unit 44 operates when the screw shaft 51 is rotating and stops when the screw shaft 51 is stopped. As a result, the hydraulic pressure supplied to the screw sliding surface increases when the screw shaft 51 is rotating, reducing the frictional resistance of the screw sliding surface and improving operating efficiency. Also, when the screw shaft 51 is stopped (i.e., during holding), the hydraulic pressure in the hydraulic chamber 721 increases due to the cell surface pressure, so the hydraulic pressure generating unit 44 can reduce energy consumption during holding by stopping hydraulic pressure generation. Furthermore, when the screw shaft 51 is rotating, the hydraulic pressure generating unit 44 generates hydraulic pressure and increases the hydraulic pressure in the hydraulic chamber 721. As a result, the normal force on the screw surface 511 decreases and the frictional force on the screw sliding surface decreases, making it possible to reduce operating energy.

[0056] <Embodiment 7> Figure 11 is a cross-sectional view showing an example configuration of module 1F according to Embodiment 7 of the present invention. As shown in Figure 11, in module 1F, the operating unit 5 is a hydraulic operating unit. The motor that rotates the screw shaft 51 is a hydraulic motor 80. The hydraulic motor 80 has a hydraulic pump O / P, an upstream oil passage 82 that supplies oil from the hydraulic pump O / P to the rotor 81 side, and a downstream oil passage 83 that returns oil from the rotor 81 side to the hydraulic pump O / P. The upstream oil passage 82 and the downstream oil passage 83 are each included in the operating unit 5. The hydraulic pump O / P supplies oil to the rotor 81 side via the upstream oil passage 82 at a high pressure. The rotor 81 is rotated by its high-pressure force, and the screw shaft 51 connected to the rotor 81 is rotated.

[0057] Furthermore, an oil passage 84 is provided between the upstream oil passage 82 and the hydraulic chamber 721, connecting the upstream oil passage 82 and the hydraulic chamber 721. A check valve 85 is provided in this oil passage 84. This check valve allows the hydraulic fluid of the operating unit 5 to flow only from the upstream oil passage 82 to the hydraulic chamber 721. This allows high-pressure oil from upstream of the hydraulic pump O / P to be supplied to the hydraulic chamber 721, thus preventing the hydraulic chamber 721 from becoming negative pressure when the laminated cell 3 expands, which would generate air and reduce the surface pressure holding force against the laminated cell 3. In addition, during operation, supplying high-pressure oil from upstream of the hydraulic pump O / P to the hydraulic chamber 721 increases the hydraulic pressure within the hydraulic chamber 721, thereby generating surface pressure holding force against the laminated cell 3 and reducing the load on the screw shaft 51 of the operating unit 5. Furthermore, if the hydraulic motor 80 fails, the hydraulic pump O / P is activated, supplying high-pressure oil upstream of the hydraulic pump O / P into the hydraulic chamber 721 to increase the hydraulic pressure in the hydraulic chamber 721. This allows the hydraulic holding unit 7 alone to maintain surface pressure on the laminated cells 3, thus providing a fail-safe mechanism.

[0058] As shown in Figure 11, the following passages are provided as connecting passages from the operating section 5 to the hydraulic holding section 7: CP1 from the outlet of the hydraulic motor 80 to the inside of the reduction gear 53, CP2 from the inside of the reduction gear 53 to the inside of the screw shaft 51, CP3 from the inside of the screw shaft 51 to the reserve tank, and CP4 from the reserve tank to the hydraulic chamber 721.

[0059] These connecting passages form an oil passage that connects the downstream oil passage of the operating unit 5 to the reserve tank of the hydraulic pressure holding unit 7. Since the hydraulic pressure after operation is higher than atmospheric pressure, it is possible to supply oil without the hydraulic chamber 721 becoming negative pressure when the stacked cells 3 expand. This makes it possible to avoid the generation of air in the hydraulic chamber 721 and the resulting decrease in holding force. Furthermore, if the operating unit 5 becomes inoperable, the hydraulic pressure in the hydraulic chamber 721 will increase as the hydraulic pressure holding unit 7 alone maintains the cell surface pressure, but since a check valve 85 is provided, a constant hydraulic pressure can be maintained, making it a fail-safe. In addition, if oil leakage occurs from the check valve 85, it is possible to prevent oil leakage from the check valve 85 and maintain a constant holding force by stopping the rotation of the hydraulic pump O / P.

[0060] Furthermore, the above-mentioned connecting passage allows the hydraulic fluid of the operating unit 5 to be supplied to the sliding surface of the operating unit 5. The operating unit 5 holds the stacked cell 3 with a constant holding force and can generate hydraulic pressure even when the hydraulic pump O / P is stopped rotating. By supplying the hydraulic pressure of the operating unit 5 to the sliding surface of the screw shaft 51, it is possible to prevent the oil film from breaking down on the screw surface 511 of the screw shaft 51, even when a constant holding force is maintained. [Explanation of Symbols]

[0061] 1, 1A, 1B, 1C, 1D, 1E, 1F... Module, 2... Housing, 3... Laminated cell, 4... Surface pressure holding mechanism, 5... Operating part, 7... Hydraulic holding part, 41, 41a, 41b... Support plate, 44... Hydraulic generation part, 46... Gas spring, 51... Screw shaft, 52... Cell load transmission part, 53... Reducer, 54... Motor, 55... Rod support part, 56... Screw support part, 57... Rod support part, 71... Hydraulic cylinder, 72... Oil chamber, 72A... High-pressure hydraulic chamber, 72B... Low-pressure hydraulic chamber, 73... Reserve tank, 74... Hydraulic piston, 75... On-off valve, 76, 77, 78... Piping, 80... Hydraulic motor, 81... Rotor, 82... Upstream oil passage, 83... Downstream oil passage, 84... Oil passage, 85... Check valve, 100... Solid-state battery, 511... Screw surface, 521... Transmission plate, 522... Transmission rod. 523... First oil passage, 531... Reducer housing, 551, 571... Oil seal, 721... Hydraulic chamber, 722... Reserve tank, 741... Second oil passage, 742... Third oil passage, 771... Check valve, 781... On-off valve, CP1, CP2, CP3, CP4... Connecting passage, O / P... Hydraulic pump

Claims

1. It is equipped with a surface pressure holding mechanism that applies surface pressure to the stacked cells of the all-solid-state battery housed in the module. The surface pressure holding mechanism has an operating part and a holding part. The operating unit includes a motor, a reduction gear, a screw shaft, a first support portion that engages with the screw surface of the screw shaft, a second support portion that supports the rod portion of the screw shaft, a cell load transmission portion that transmits load to the stacked cells, and a third support portion that supports the cell load transmission portion. The holding part includes a hydraulic piston, a hydraulic cylinder including a hydraulic chamber, and a reserve tank. The hydraulic piston, the cell load transmission unit, and the first support unit are integrally formed. A solid-state battery structure in which the screw shaft and the cell load transmission section penetrate the hydraulic cylinder of the holding section.

2. The all-solid-state battery structure according to claim 1, wherein the second support portion and the third support portion are integrally formed on the hydraulic cylinder.

3. The all-solid-state battery structure according to claim 1 or 2, wherein the inside of the hydraulic cylinder is divided into two oil chambers by the hydraulic piston, one of the oil chambers is the hydraulic chamber, the other oil chamber is the reserve tank, and the hydraulic chamber and the reserve tank are connected by an oil passage.

4. The all-solid-state battery structure according to claim 1 or 2, wherein a screw engagement portion is formed between the screw shaft and the first support portion so as to connect the hydraulic chamber and the reserve tank.

5. The all-solid-state battery structure according to claim 1 or 2, wherein the amount of lubrication supplied to the sliding surface of the screw shaft is greater when the screw shaft is rotating than when it is stopped.

6. The all-solid-state battery structure according to claim 1 or 2, wherein at least a portion of the threaded surface of the screw shaft is exposed to the hydraulic chamber.

7. The all-solid-state battery structure according to claim 1 or 2, wherein the length of the meshing portion on the threaded surface of the screw shaft is shorter when the stacked cell is contracted than when the stacked cell is expanded.

8. The all-solid-state battery structure according to claim 1 or 2, wherein the surface pressure holding mechanism includes a passive surface pressure holding mechanism.

9. The second support portion has an oil seal between it and the screw shaft. The all-solid-state battery structure according to claim 1 or 2, wherein the hydraulic pressure acting on the oil seal is higher when the screw shaft is stopped than when it is rotating.

10. The system further comprises a hydraulic power generation unit that supplies hydraulic pressure to the hydraulic chamber, The all-solid-state battery structure according to claim 1 or 2, wherein the hydraulic generation unit operates while the screw shaft is rotating and stops when the screw shaft is stopped.

11. The all-solid-state battery structure according to claim 1 or 2, wherein the volume of the oil chamber inside the rod of the hydraulic piston is varied in accordance with the change in the amount of oil in the hydraulic chamber when the hydraulic piston is operating, thereby keeping the total volume of the hydraulic chamber and the oil chamber inside the rod of the hydraulic piston constant.

12. The all-solid-state battery structure according to claim 1 or 2, wherein the oil chamber inside the hydraulic piston or inside the rod of the hydraulic piston is an accumulator.

13. The all-solid-state battery structure according to claim 1 or 2, wherein the hydraulic chamber and the oil chamber inside the rod of the hydraulic piston are in communication through the gap of the screw engagement portion.

14. The all-solid-state battery structure according to claim 1 or 2, wherein the hydraulic chamber and the oil chamber inside the rod of the hydraulic piston are sealed inside the module.

15. The operating unit further comprises a reduction gear attached to the screw shaft and a reduction gear housing that houses the reduction gear. The reduction gear housing is fixed to the hydraulic cylinder, The all-solid-state battery structure according to claim 1 or 2, wherein the inside of the hydraulic cylinder and the inside of the reduction gear housing are in communication.

16. The aforementioned operating part is a hydraulic operating part, The all-solid-state battery structure according to claim 1 or 2, wherein an oil passage is formed that connects the downstream oil passage of the hydraulic operating section with the reserve tank.

17. The all-solid-state battery structure according to claim 16, wherein the hydraulic fluid of the hydraulic operating part is supplied to the sliding surface of the hydraulic operating part.

18. An oil passage communicating with the hydraulic chamber is formed upstream of the hydraulic operating section, and a check valve is provided in the oil passage. The all-solid-state battery structure according to claim 16, wherein the hydraulic fluid of the hydraulic operating section is permitted to flow only from the oil passage into the hydraulic chamber.

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