Cell surface pressure retention mechanism for all-solid-state batteries

Abstract

A cell surface pressure retention mechanism for an all-solid-state battery is provided, which can prevent the device from becoming larger. [Solution] The cell surface pressure maintaining mechanism includes a first maintaining section 12 that is arranged inside a module 1 that stores stacked cells 11 of an all-solid-state battery and maintains the surface pressure of the stacked cells 11 using a first fluid as a working fluid, a second maintaining section 13 that is arranged inside the module 1 and maintains the surface pressure of the stacked cells 11 using a second fluid as a working fluid, an electric pump 2 that is arranged outside the module 1 and uses the second fluid as a working fluid, and an external flow path 3 that is arranged outside the module 1 and transmits the pressure of the second fluid from the electric pump 2 to the second maintaining section 13.

Description

[Technical Field]

[0001] The present invention relates to a cell surface pressure maintaining mechanism for an all-solid-state battery. [Background technology]

[0002] Patent Document 1 discloses a conventional technique relating to a cell surface pressure maintaining mechanism for an all-solid-state battery.

[0003] Patent Document 1 describes a battery case device equipped with a battery case having a storage space for an all-solid-state battery, in which compressed and heated gas is supplied to the storage space and the state of the gas in the storage space is adjusted by an adjustment means so that the output required in actual use of the battery is stable. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-92007 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the battery case device described above has the problem that the device becomes large if all of the stacked cells of the all-solid-state battery are stored in the storage space and the structure is made to withstand high pressure. Furthermore, if oil is used as the working fluid, a hydraulic pressure generating device and an oil supply path are required outside the battery case (sealed chamber), and measures to prevent oil leakage must also be provided, further compounding the problem of large size.

[0006] An object of the present invention is to provide a cell surface pressure maintaining mechanism for an all-solid-state battery that can prevent the device from becoming large. [Means for solving the problem]

[0007] One aspect of the present invention provides a cell surface pressure holding mechanism including: (1) a first holding unit that is disposed inside a module that stores stacked cells of an all-solid-state battery and that holds the surface pressure of the stacked cells using a first fluid as a working fluid; (2) a second holding unit that is disposed inside the module and that holds the surface pressure of the stacked cells using a second fluid as a working fluid; (3) an electric pump that is disposed outside the module and that uses the second fluid as a working fluid; and (4) an external flow path that is disposed outside the module and that transmits the pressure of the second fluid from the electric pump to the second holding unit. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is expected to provide a cell surface pressure retention mechanism for an all-solid-state battery that can prevent the device from becoming large. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic perspective view showing the overall configuration of an all-solid-state battery according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a diagram illustrating an example of a specific configuration within a module that constitutes the all-solid-state battery of FIG. 1. [Figure 3] FIG. 3 is a cross-sectional view corresponding to the AA cross-sectional view of FIG. [Figure 4] 3 is a view corresponding to the cross-sectional view taken along the line BB in FIG. 2, showing the laminated cell at its maximum contraction. [Figure 5] 3 is a view corresponding to the cross-sectional view taken along the line BB in FIG. 2, showing the laminated cell at its maximum expansion. [Figure 6] 10A and 10B are diagrams illustrating an example of control of the cell surface pressure maintaining mechanism of the present embodiment. [Figure 7] FIG. 3 is a diagram illustrating an example in which the configuration is partially different from the example in FIG. 2. [Figure 8] FIG. 3 is a diagram illustrating an example in which the configuration is partially different from the example in FIG. 2. [Figure 9] FIG. 3 is a diagram illustrating an example in which the configuration is partially different from the example in FIG. 2. DETAILED DESCRIPTION OF THE INVENTION

[0010] Hereinafter, embodiments of the present invention (hereinafter referred to as "embodiments") will be described in detail with reference to the drawings. Note that each drawing is a schematic view and may differ from the actual product. Furthermore, the embodiments of the present invention shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the structure, arrangement, etc. of component parts to those described below. The technical concept of the present invention can be modified in various ways within the technical scope defined by the claims. 〔composition〕

[0011] FIG. 1 is a schematic perspective view showing the overall configuration of an all-solid-state battery 100 according to an embodiment of the present invention.

[0012] The all-solid-state battery 100 includes a plurality of modules 1, an electric pump 2 arranged outside the plurality of modules 1, and a first pipe 3 and a second pipe 4 connecting the electric pump 2 to each module 1.

[0013] Each module 1 houses stacked cells 11. Inside each module 1, a first holding section 12 and a second holding section 13 are arranged to separately maintain the surface pressure of the stacked cells 11. The holding section 12 uses the first fluid as the working fluid. The electric pump 2 and the second holding section 13 use the second fluid as the working fluid.

[0014] In this embodiment, the first fluid is oil and the second fluid is air. The electric pump 2 is a compressed air pump. The kinematic viscosity of the air (second fluid) is lower than that of the oil (first fluid). The bulk modulus of the air (second fluid) is higher than that of the oil (first fluid).

[0015] The first pipe 3 is an external flow path that transmits hydraulic pressure (pressure of the second fluid) from the electric pump 2 to the second holding portion 13 inside each module 1. The first pipe 3 has branch pipes 31 leading to each module 1. An on-off valve 32 and a check valve 33 are installed in each branch pipe 31.

[0016] The second piping 4 is intended to return the air (second fluid) coming out of the second holding section 13 to the electric pump 2, and a branch pipe 41 leading to the second piping 4 is connected to the second holding section 13 of each module 1.

[0017] An example of a specific configuration inside the module 1 (first embodiment) will be described with reference to FIGS.

[0018] The module 1 has a rectangular parallelepiped housing 10, and stacked cells 11 are arranged in the upper part of the housing 10. The stacked cells 11 are installed on a support plate 111. A pair of first holding parts 12 and one second holding part 13 are arranged in the space below the housing 10 (the space below the support plate 111).

[0019] The first holding part 12 is composed of a double-acting single-rod hydraulic cylinder. The tip of the rod 121 of the hydraulic cylinder (the end opposite to the piston 122) is formed in a disk shape. The upper surface of this disk part 123 is fixed to the lower surface of the support plate 111.

[0020] The second holding portion 13 is positioned in the center of the space below the housing 10, and the two first holding portions 12 are positioned on either side of the second holding portion 13 in the long side direction when viewed in a plane of the rectangular parallelepiped that forms the housing 10.

[0021] The second holding section 13 is composed of a reducer 13a made of a wave gear and a cylindrical cell abutment member 13b that moves with the rotation of the output shaft of the reducer 13a. That is, a male thread is formed on the outer periphery of the elastic outer toothed ring of the reducer 13a, and a female thread that screws into this is formed on the inner periphery of the cell abutment member 13b. The input shaft of the reducer 13a is driven by compressed air supplied from a branch pipe 31 of the first piping 3.

[0022] As shown in Figures 3 and 4, a reserve tank 15 is installed inside the housing 10, and the reserve tank 15 is connected to the low-pressure hydraulic chamber 12b of the hydraulic cylinder that constitutes the first holding portion 12 by a pipe 16. Parallel pipes 17 and 18 are provided to connect the high-pressure hydraulic chamber 12a and the low-pressure hydraulic chamber 12b, with a check valve 171 provided in one pipe 17 and an on-off valve 181 provided in the other pipe 18. Therefore, by controlling the opening and closing of the on-off valve 181, the piston 122 of the hydraulic cylinder can be operated. When the on-off valve 181 is open, oil is supplied to the high-pressure hydraulic chamber 12a from both the low-pressure hydraulic chamber 12b and the reserve tank 15.

[0023] 4 shows the stacked cells 11 at maximum contraction, and FIG 5 shows the stacked cells 11 at maximum expansion. In FIG 5, the reserve tank 15 and piping etc. are omitted.

[0024] As described above, the all-solid-state battery 100 of this embodiment has a cell surface pressure holding mechanism including the first holding section 12, the second holding section 13, the electric pump 2, and the external flow path (first piping 3).

[0025] 2 includes an inlet passage for compressed air from the electric pump 2 (branch pipe 31 of the first piping 3 shown in FIG. 1) and an outlet passage 45 for compressed air, with a check valve 33 provided in the inlet passage (branch pipe 31) and the outlet passage 45 being open to the atmosphere. Note that, unlike the example in FIG. 2, the second holding section 13 in FIG. 1 includes a branch pipe 41 as an outlet passage for compressed air, and the discharged compressed air is returned to the electric pump 2 from the second piping 4 for circulating use. [Operation]

[0026] When the first holding part 12 is in operation, the hydraulic pressure in the high-pressure hydraulic chamber 12a and the low-pressure hydraulic chamber 12b is adjusted by opening and closing the on-off valve 181, thereby moving the hydraulic piston 122 up and down, thereby moving the support plate 111 up and down. In this way, the holding force of the first holding part 12 is exerted.

[0027] When the second holding unit 13 is operating, the electric pump 2 is driven to supply compressed air to the first piping 3. At that time, if the second holding unit 13 is to be operated in all modules 1, all of the on-off valves 32 are opened. Accordingly, the compressed air supplied from the electric pump 2 to the first piping 3 is supplied to the second holding unit 13 from the branch pipes 31 of each module 1.

[0028] In the second holding part 13, the input shaft of the reducer is driven by compressed air supplied from the branch pipe 31, and the rotation of the output shaft of the reducer causes the cell abutment member 13b to stroke, thereby moving the support plate 111 up and down. In this way, the holding force of the second holding part 13 is exerted.

[0029] The cell surface pressure retaining mechanism of this embodiment is operated, for example, as shown in FIG.

[0030] While charging and discharging are stopped, the cell surface pressure is maintained by the holding force of the first holding unit 12. When charging starts, the cell expands and the cell surface pressure increases, and when the holding force by the first holding unit 12 increases during charging and reaches a predetermined value (predetermined value 1), the on-off valve 181 is opened to release some of the oil in the high-pressure side hydraulic chamber 12a of the first holding unit 12 into the reserve tank 15, thereby reducing the holding force by the first holding unit 12. As a result, the expanded stacked cell 11 is held at an appropriate surface pressure (low surface pressure).

[0031] At this point, holding by the second holding unit also begins. By using holding by the second holding unit in combination, opening and closing of the on-off valve 181 becomes possible in a state where the oil pressure is reduced, thereby reducing the load acting on the on-off valve 181. As a result, deterioration of noise and vibration due to sudden fluctuations in oil pressure can be prevented, and fluctuations in the cell surface pressure can be suppressed.

[0032] Furthermore, when discharge is started while charging and discharging are stopped (while held by first holding unit 12), cell contraction occurs, reducing the cell surface pressure, and the holding force by first holding unit 12 decreases during discharge until it reaches a predetermined value (predetermined value 2), at which point holding by second holding unit 13 begins. At this time, holding by first holding unit 12 continues, but the holding force is reduced. In this way, holding by first holding unit 12 is maintained while holding by second holding unit 13 is switched to, preventing a drop in cell surface pressure during switching.

[0033] Furthermore, when the holding force of second holding unit 13 reaches a predetermined value (predetermined value 1) during discharge, holding by second holding unit 13 is switched to holding by first holding unit 12. This reduces the operating frequency of second holding unit 13, reduces operating energy, and prevents overheating of second holding unit 13. [Action, effect]

[0034] According to the cell surface pressure retention mechanism of this embodiment, since it has two independent retention parts, the first retention part 12 and the second retention part 13, the cell surface pressure retention function can be performed by the first retention part 12 without being affected even if there is a leakage of the working fluid in the second retention part 13. Furthermore, if the first retention part 12 fails, it is possible to prevent the first fluid from leaking out of the module via the second retention part 13, and the second retention part 13 can independently maintain the cell surface pressure.

[0035] When a mechanical actuator mechanism that does not use fluid is used as the operating mechanism, an actuator must be provided for each module, or a transmission mechanism that mechanically transmits the power of a single actuator is required, resulting in a large and heavy device.In contrast, the cell surface pressure retention mechanism of this embodiment uses fluid, making it possible to transmit compressed fluid energy from a single drive energy source to all multiple modules, eliminating the need for an actuator mechanism for each module and allowing for a smaller and lighter device.

[0036] Furthermore, since the first holding portion 12, which uses oil (first fluid) as a working fluid, is disposed inside the module 1, oil leakage to the outside of the module 1 can be prevented.

[0037] Furthermore, since a hydraulic cylinder is used as the first holding portion 12, the oil sealing performance is improved and a decrease in cell surface pressure during holding can be suppressed.

[0038] In addition, since the second fluid is air, it can be discharged into the atmosphere after power transmission, and there is no need for a recovery section for the second fluid or a return path to the electric pump, making it possible to reduce the size.In addition, since the temperature of the second fluid rises due to compression, discharging it to the outer periphery of the module provides a temperature control effect. Other Embodiments

[0039] FIG. 7 shows an example (second embodiment) in which a compression spring 5 is installed inside the high-pressure hydraulic chamber 12a of the first holding unit 12. Other than this, it is the same as the example (first embodiment) of FIG. 2. That is, the example of FIG. 7 is equipped with a passive cell surface pressure application mechanism. Furthermore, by installing the compression spring 5, the piston 122 of the hydraulic cylinder, which is the first holding unit 12, can be made to follow the position of the stacked cells 11 during operation, eliminating the need for hydraulic control of the first holding unit 12. Furthermore, while the hydraulic pressure of the hydraulic holding mechanism of the first holding unit 12 may decrease during the contraction process of the stacked cells 11, the inclusion of the compression spring 5 ensures that the holding force is maintained even if the hydraulic pressure temporarily decreases.

[0040] Furthermore, in the example shown in Figure 8, unlike the example in Figure 4 (first embodiment), there is no piping 16 connecting the reserve tank 15 and the low-pressure side hydraulic chamber 12b, and when the on-off valve 181 is open, oil is supplied to the high-pressure side hydraulic chamber 12a only from the reserve tank 15.

[0041] 9 (third embodiment) is an example in which an accumulator 19 is provided instead of the reserve tank 15 in the example shown in Fig. 8. Parallel-arranged pipes 17 and 18 connecting the accumulator 19 and the high-pressure side hydraulic chamber 12a are provided with on-off valves 172 and 181 and check valves 171 and 182, respectively. In other words, the example shown in Fig. 9 has a mechanism that recovers hydraulic pressure from the hydraulic chamber to the accumulator when the stacked cells expand, and returns the hydraulic pressure of the accumulator to the hydraulic chamber when the stacked cells contract. [Each aspect and its effects] <First aspect>

[0042] A first aspect of the present invention is a cell surface pressure holding mechanism including: (1) a first holding unit that is disposed inside a module that stores stacked cells of an all-solid-state battery and that holds the surface pressure of the stacked cells using a first fluid as a working fluid; (2) a second holding unit that is disposed inside the module and that holds the surface pressure of the stacked cells using a second fluid as a working fluid; (3) an electric pump that is disposed outside the module and that uses the second fluid as a working fluid; and (4) an external flow path that is disposed outside the module and that transmits the pressure of the second fluid from the electric pump to the second holding unit.

[0043] According to the cell surface pressure retention mechanism of the first aspect, since the cell surface pressure retention mechanism has two independent retention parts, the first retention part and the second retention part, even if there is a leakage of the working fluid from the second retention part, the cell surface pressure retention function can be performed by the first retention part without being affected by the leakage. Furthermore, if the first retention part fails, it is possible to prevent the first fluid from leaking out of the module via the second retention part, and the cell surface pressure can be maintained by the second retention part alone.

[0044] When a mechanical actuator mechanism that does not use fluid is used as the actuation mechanism, an actuator must be provided for each module, or a transmission mechanism that mechanically transmits the power of a single actuator is required, resulting in a large and heavy device.In contrast, the cell surface pressure retention mechanism of the first aspect uses fluid, making it possible to transmit compressed fluid energy from a single drive energy source to all multiple modules, eliminating the need for an actuator mechanism for each module and allowing for a smaller and lighter device.

[0045] When a passive holding mechanism such as a metal spring is used as the holding section, the cell compressive load changes in response to the expansion and contraction of the stacked cells. In contrast, in the cell surface pressure holding mechanism of the first aspect, by using a fluid-sealed holding mechanism as the holding section, it becomes easy to ensure a large stroke in response to the expansion and contraction of the stacked cells, and since the cell compressive load can be maintained by sealing the fluid chamber at the corresponding position, it becomes possible to obtain a predetermined cell compressive load at any position. <Second mode>

[0046] In a second aspect, in the cell surface pressure retention mechanism of the first aspect, the kinetic viscosity of the second fluid is lower than that of the first fluid, i.e., the first fluid has a high kinetic viscosity, and the second fluid has a low kinetic viscosity.

[0047] When the cell surface pressure retention mechanism of the first aspect is applied to an all-solid-state battery having multiple modules, the external flow path (the flow path for the second fluid connecting the electric pump and the second retention part of each module) becomes long and the required volume becomes large. In contrast, with the cell surface pressure retention mechanism of the second aspect, by using a second fluid with low kinetic viscosity, the flow path resistance of the external flow path can be reduced, thereby reducing the operating energy, and the weight can be reduced due to the lower density, thereby greatly reducing the weight of the device.

[0048] Furthermore, the viscous resistance of the electric pump is reduced, allowing the electric pump to be made smaller.

[0049] Furthermore, since the flow resistance between the electric pump and each module can be reduced, the diameter of the piping for the second fluid can be reduced, making it more compact, and the flexibility in piping layout increases, improving vehicle mountability.

[0050] By using a first fluid (working fluid of the holding part) with a high kinetic viscosity, leakage of the fluid from within the module can be reduced, and the holding energy can be reduced. <Third mode>

[0051] In a third aspect, in the cell surface pressure retention mechanism of the first aspect, the bulk modulus of the second fluid is higher than that of the first fluid, i.e., the first fluid has a low bulk modulus and the second fluid has a high bulk modulus.

[0052] Since the first fluid (working fluid in the first holding portion) has a low bulk modulus, it is possible to reduce the temperature rise caused by compression of the first fluid in the first holding portion, and to prevent a decrease in viscosity due to a temperature rise and leakage due to a decrease in viscosity.

[0053] A change in the volume of the first fluid due to a change in temperature of the first fluid can be reduced, and the amount of change in the holding force due to a change in temperature of the stacked cells can be reduced.

[0054] Since the second fluid (the working fluid of the electric pump) has a high bulk modulus, the temperature of the second fluid increases when the electric pump is operating, and the viscosity decreases, thereby reducing the operating resistance.

[0055] The high bulk modulus of the second fluid makes it easier for the second fluid to absorb pressure fluctuations caused by sudden starts and stops of the electric pump, thereby suppressing noise caused by sudden pressure fluctuations.

[0056] Since the piping path (external flow path) for the second fluid located outside the module is long, the high bulk modulus of the second fluid allows the external flow path to also function as an accumulator that stores compression energy within the piping, which makes it possible to downsize or even eliminate the accumulator. <Fourth aspect>

[0057] In a fourth aspect, in the cell surface pressure retention mechanism of the first aspect, the first fluid (the working fluid of the first retention portion) and the second fluid (the working fluid of the electric pump and the second retention portion) are the same fluid.

[0058] According to this, since the first fluid and the second fluid are the same fluid, the flow path for recovering the leaking first fluid and the second fluid can be shared, thereby making it possible to reduce the size.

[0059] It is preferable that the compressor has a mechanism for raising the temperature of the second fluid to a temperature higher than that of the first fluid by increasing the temperature of the second fluid during compression by the electric pump or by having the second fluid recover heat generated by the electric pump. <Fifth aspect>

[0060] In a fifth aspect, in the cell surface pressure retaining mechanism of the first aspect, the second fluid dissipates heat through an external flow path (a flow path from the electric pump to the second retaining portion).

[0061] The cell surface pressure retention mechanism of the fifth aspect can eliminate the need for a temperature adjustment device for the second fluid, thereby enabling the electric pump to be made more compact. Furthermore, the compressed second fluid is cooled as it passes through the flow paths from the electric pump to each module, thereby preventing a temperature rise within the module. <Sixth mode>

[0062] In a sixth aspect, the cell surface pressure retaining mechanism of the first aspect further comprises a temperature adjusting device for the second fluid in the external flow path.

[0063] According to the cell surface pressure retention mechanism of the sixth aspect, the temperature regulator increases the temperature of the second fluid in the external flow path at low temperatures to reduce viscosity, thereby improving operating efficiency. Regulating the temperature of the second fluid also has the effect of increasing the gas volume and compression pressure. Furthermore, since there is no need to install a temperature regulator inside the module, the module can be made smaller. <Seventh mode>

[0064] In a seventh aspect, in the cell surface pressure retaining mechanism of the first aspect, the first fluid and the second fluid are oils, and the viscosity of the first fluid is higher than the viscosity of the second fluid.

[0065] By using a high viscosity oil for the first fluid and a low viscosity oil for the second fluid, the operating energy of the second holding unit can be reduced regardless of temperature, and fluid leakage from the first holding unit can be reduced, thereby reducing the holding energy of the first holding unit. <Eighth aspect>

[0066] An eighth aspect is the cell surface pressure retention mechanism of the first aspect, in which the first fluid (the working fluid of the first retention portion) is oil, and the second fluid (the working fluid of the electric pump and the second retention portion) is air.

[0067] According to the cell surface pressure retaining mechanism of the eighth aspect, the following effects can be obtained.

[0068] Since oil viscosity increases at low temperatures, oil can be held stably without leaks by using hydraulic pressure.

[0069] The first fluid is used in sealed areas within the module and is resistant to deterioration, so oil with excellent sealing properties can be used, eliminating the need for replacement.

[0070] Since the oil usage is contained within the module, oil leakage to the outside of the module can be avoided.

[0071] The first fluid is almost stationary in the first holding section, and even when it does move, it is at a very low speed, so there is little oil deterioration, and by making it an oil-sealed type that does not require oil changes, it is possible to reduce the risk of oil leaks by making it maintenance-free, compact, and lightweight, and by eliminating oil leak paths.

[0072] Since the working fluid of the second holding portion is air, the second holding portion can be driven by a highly efficient air motor at low temperatures, and therefore the operating energy at low temperatures can be reduced.

[0073] Because the working fluid in the second holding section is air, which has a lower viscosity than oil, the viscous resistance of the second holding section can be further reduced and operating efficiency can be improved. Also, because gas increases in volume with a temperature rise more than liquid, using air as the working fluid in the second holding section can increase the temperature rise effect caused by compression by the electric pump.

[0074] Since the working fluid in the second holding section is air, there is no environmental impact even if a leak occurs from the flow path, and since a leak recovery section is not required, the device can be made smaller.

[0075] When air is used as the working fluid for the first holding portion, the influence of pressure changes due to temperature changes is large, but by using oil, the influence of temperature can be reduced.

[0076] By using compressed air as the working fluid (working energy source) of the second holding section, even if there is a change in temperature of the air on the intake side of the compressed air pump, the change in pressure is small, and therefore the effect of the generated pressure is small.

[0077] By using compressed air as the working fluid (source of working energy) for the second holding section, compressed air can be efficiently generated by utilizing the pressure of the wind from the vehicle when it is running and increasing the inlet pressure of the compressed air pump when increased working energy is required. <Ninth aspect>

[0078] In a ninth aspect, in the cell surface pressure holding mechanism of the eighth aspect, the electric pump is a compressed air pump, and the mechanism is provided with an inlet passage for compressed air from the compressed air pump to the second holding section and an outlet passage for compressed air from the second holding section to the outside of the module, a check valve is provided in the inlet passage, and the outlet passage is open to the atmosphere.

[0079] According to the cell surface pressure retaining mechanism of the ninth aspect, the following effects can be obtained.

[0080] In the cell surface pressure retention mechanism of the eighth aspect, the second fluid is air, so the second fluid can be discharged to the atmosphere after power transmission. In the cell surface pressure retention mechanism of the ninth aspect, the discharge passage is open to the atmosphere, so there is no need for a recovery section for the second fluid or a return path to the electric pump, which makes it possible to achieve miniaturization.

[0081] Furthermore, since the temperature of the second fluid is increased by compression, a temperature control effect can be obtained by discharging the second fluid to the outer periphery of the module. <Tenth Aspect, Inventor's Claim 8>

[0082] The tenth aspect is a cell surface pressure retaining mechanism of the ninth aspect, which is provided with a plurality of modules, and has on-off valves in the external flow paths (air supply paths to the second retaining section) of the plurality of modules, and has an on-off valve control means for limiting the number of modules that open the on-off valves under conditions where the load on the compressed air pump is high.

[0083] In the cell surface pressure retention mechanism of the ninth aspect, the first retention unit operated by oil and the second retention unit operated by air are independently arranged inside the module unit. Therefore, in some modules, it is possible to operate only the first retention unit without operating the second retention unit, thereby providing a period during which compressed air is not supplied to the second retention unit. And in the cell surface pressure retention mechanism of the tenth aspect, the on-off valve control means limits the number of modules that open the on-off valve under conditions of high load on the compressed air pump, thereby reducing the maximum output of the compressed air pump.

[0084] Therefore, according to the cell surface pressure holding mechanism of the tenth aspect, the compressed air pump can be made smaller than when compressed air is always supplied to all modules and the second holding section is always operated in all modules. <Eleventh aspect>

[0085] In an eleventh aspect, in the cell surface pressure retaining mechanism of the eighth aspect, the oil pressure retaining mechanism constituting the first retaining section comprises a hydraulic cylinder and an accumulator connected to the hydraulic chamber of the hydraulic cylinder via an oil passage, the oil passage having an on-off valve, and a mechanism for recovering oil pressure from the hydraulic chamber to the accumulator when the stacked cells expand, and returning the oil pressure of the accumulator to the hydraulic chamber when the stacked cells contract.

[0086] According to the cell surface pressure maintaining mechanism of the eleventh aspect, the energy of the expansion of the stacked cells is recovered in the accumulator as hydraulic pressure, and the recovered hydraulic pressure is returned to the high-pressure chamber the next time the stacked cells contract, thereby reducing the operating energy. In addition, by recovering oil in the accumulator instead of a reserve tank, a reserve tank is no longer necessary, which makes it possible to avoid an increase in size. <Twelfth mode>

[0087] A twelfth aspect is the cell surface pressure retaining mechanism of the eighth aspect, which includes a passive cell surface pressure applying mechanism inside the hydraulic pressure retaining mechanism that constitutes the first retaining portion.

[0088] As a passive type cell surface pressure applying mechanism, a configuration in which a compression spring is built into the hydraulic chamber of a hydraulic cylinder or into the piston rod of a hydraulic cylinder can be given. By having this configuration, the cell surface pressure retaining mechanism of the twelfth aspect can obtain the following effects.

[0089] During operation, the piston of the hydraulic cylinder of the first holding unit can be made to follow the position of the stacked cells, eliminating the need for hydraulic control of the first holding unit. Furthermore, while the hydraulic pressure of the hydraulic holding mechanism of the first holding unit may drop during the contraction process of the stacked cells, the inclusion of a compression spring ensures that the holding force is maintained even if the hydraulic pressure temporarily drops. Furthermore, by utilizing the space inside the hydraulic cylinder to place the compression spring, the device can be made more compact. <Another Example 1>

[0090] The hydraulic holding mechanism constituting the first holding section is provided with a cylinder and a piston, and a hydraulic chamber formed by the cylinder and the piston is formed. The hydraulic chamber is provided with a switching valve that opens and closes the hydraulic chamber and a check valve that only allows oil to flow into the hydraulic chamber. The switching valve is closed when the cell stops charging / discharging or when discharging, and can be opened and closed when charging.

[0091] With this, the cell contracts during discharge, but because it is equipped with a check valve, oil can be supplied to the hydraulic chamber when the hydraulic piston strokes following the cell, so the hydraulic chamber can be constantly filled with oil according to the operation of the second holding part, and can be held by hydraulic pressure when the second holding part is stopped.

[0092] During charging, the cells expand, pushing the hydraulic piston and increasing the oil pressure, but by opening the switching valve, the amount of oil can be adjusted and the piston position can be made to follow the cell. <Another aspect 2>

[0093] The hydraulic pressure holding mechanism constituting the first holding section is provided with a hydraulic cylinder, two oil chambers on either side of a hydraulic piston, an oil passage connecting the two oil chambers, and a valve that can open and close the oil passage, and the hydraulic piston position is operated only by opening and closing the valve.

[0094] This eliminates the need to take measures to prevent oil from leaking to the outside because the hydraulic circuit is closed.

[0095] Furthermore, because the amount of oil change during a piston stroke differs between the hydraulic chamber on the side with the rod and the hydraulic chamber on the side without the rod, a reserve tank is required, but because the hydraulic chamber on the non-compression side can be used as part of the reserve tank, the reserve tank can be made smaller.

[0096] Furthermore, the only operating energy required for the hydraulic pressure holding mechanism is the energy consumed for opening and closing the valve, thereby achieving energy savings. <Another aspect 3>

[0097] The second holding section is provided with a pneumatic cylinder consisting of a cylinder and a piston, and transmits a compressive force from the piston to the cell.

[0098] According to this, by adopting a cylinder piston structure with excellent airtightness, it is possible to suppress leakage of compressed air and generate cell surface pressure without increasing operating energy. <Another Example 4>

[0099] If the holding force of the second holding unit reaches or exceeds a predetermined value during discharge, the holding force of the second holding unit is reduced and the holding unit is switched to holding by the first holding unit.

[0100] This reduces the operating frequency of the second holding portion, reduces the operating energy, and prevents the second holding portion from overheating. <Another Example 5>

[0101] If the cell surface pressure drops below a predetermined value while being held by the first holding unit during discharge, holding by the second holding unit is also started while holding by the first holding unit.

[0102] According to this, since the state of holding by the first holding portion is maintained while holding by the second holding portion is switched, it is possible to prevent a decrease in cell surface pressure during the switching. <Another aspect 6>

[0103] The first holding unit is a hydraulic pressure holding mechanism, and if the cell surface pressure increases above a predetermined value while being held by the first holding unit during charging, some of the oil in the high hydraulic pressure chamber of the first holding unit is released to reduce the cell surface pressure.

[0104] This allows the first holding portion to maintain the holding force without operating the second holding portion, thereby reducing the operating energy. <Another aspect 7>

[0105] The first holding unit is a hydraulic holding mechanism, and if the cell surface pressure increases above a predetermined value while being held by the first holding unit during charging, some of the oil in the high hydraulic chamber of the first holding unit is released to reduce the cell surface pressure, and holding by the second holding unit is also initiated.

[0106] With this, the second holding section bears the holding force when the valve of the hydraulic chamber in the first holding section is opened or closed, so the valve of the hydraulic chamber can be opened and closed when the oil pressure is low, reducing the load acting on the valve, preventing deterioration of noise and vibration due to sudden fluctuations in oil pressure, and suppressing fluctuations in cell surface pressure. [Explanation of symbols]

[0107] REFERENCE SIGNS LIST 1 Module, 2 Electric pump, 3 First pipe (external flow path), 4 Second pipe (compressed air discharge passage), 11 Stacked cell, 12 First holding section (hydraulic cylinder), 13 Second holding section, 14 Pipe (internal flow path), 31 Branch pipe (compressed air introduction passage), 33 Check valve, 41 Branch pipe (compressed air discharge passage), 45 Compressed air discharge passage

Claims

1. a first holding unit that is disposed inside a module that stores stacked cells of the all-solid-state battery and that holds a surface pressure of the stacked cells using a first fluid as a working fluid; a second holding section that is disposed inside the module and that holds the surface pressure of the stacked cells using a second fluid as a working fluid; an electric pump that is disposed outside the module and uses the second fluid as a working fluid; an external flow path disposed outside the module, which transmits the pressure of the second fluid from the electric pump to the second holding portion; A cell surface pressure maintaining mechanism.

2. 2. The cell surface pressure maintaining mechanism according to claim 1, wherein the dynamic viscosity of the second fluid is lower than the dynamic viscosity of the first fluid.

3. The cell surface pressure maintaining mechanism according to claim 1 , wherein the bulk modulus of the second fluid is higher than the bulk modulus of the first fluid.

4. 2. The cell surface pressure maintaining mechanism according to claim 1, wherein the first fluid and the second fluid are the same fluid.

5. The cell surface pressure maintaining mechanism according to claim 1 , wherein the second fluid dissipates heat through the external flow path.

6. The cell surface pressure maintaining mechanism according to claim 1 , further comprising a temperature adjusting device for adjusting the temperature of the second fluid in the external flow path.

7. 2. The cell surface pressure maintaining mechanism according to claim 1, wherein the first fluid and the second fluid are oils, and the viscosity of the first fluid is higher than the viscosity of the second fluid.

8. 2. The cell surface pressure maintaining mechanism according to claim 1, wherein the first fluid is oil and the second fluid is air.

9. the electric pump is a compressed air pump; a compressed air introduction passage from the compressed air pump to the second holding portion, and a compressed air discharge passage from the second holding portion to the outside of the module, 9. The cell surface pressure maintaining mechanism according to claim 8, wherein the inlet passage is provided with a check valve, and the outlet passage is open to the atmosphere.

10. A plurality of the modules are provided, an on-off valve is provided in the external flow path of each of the plurality of modules; 10. The cell surface pressure maintaining mechanism according to claim 9, further comprising a control means for controlling the on-off valves for limiting the number of the modules that open the on-off valves when the load on the compressed air pump is high.

11. The hydraulic pressure holding mechanism constituting the first holding portion includes a hydraulic cylinder and an accumulator connected to a hydraulic chamber of the hydraulic cylinder via an oil passage, The oil passage is provided with an on-off valve, 9. The cell surface pressure maintaining mechanism according to claim 8, further comprising a mechanism for recovering hydraulic pressure from the hydraulic chamber to the accumulator when the stacked cells are expanded, and returning the hydraulic pressure of the accumulator to the hydraulic chamber when the stacked cells are contracted.

12. The cell surface pressure holding mechanism according to claim 8, further comprising a passive cell surface pressure applying mechanism provided inside the hydraulic pressure holding mechanism constituting the first holding portion.

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