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 holding mechanism comprises: a holding section 12, which is arranged inside a module 1 that stores stacked cells 11 of an all-solid-state battery, and which holds the surface pressure of the stacked cells using a first fluid as a working fluid; an electric pump 2, which is arranged outside the module and which uses a second fluid as a working fluid; a pressure conversion section 13, which is arranged inside the module and converts the pressure of the second fluid into the pressure of the first fluid; an external flow path 3, which is arranged outside the module and transmits the pressure of the second fluid from the electric pump to the pressure conversion section; and an internal flow path 4, which is arranged inside the module and transmits the pressure of the first fluid from the pressure conversion section to the holding section.

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 holding unit disposed inside a module storing stacked cells of an all-solid-state battery, the holding unit holding the surface pressure of the stacked cells using a first fluid as a working fluid; (2) an electric pump disposed outside the module, the electric pump using a second fluid as a working fluid; (3) a pressure conversion unit disposed inside the module, converting the pressure of the second fluid into the pressure of the first fluid; (4) an external flow path disposed outside the module, transmitting the pressure of the second fluid from the electric pump to the pressure conversion unit; and (5) an internal flow path disposed inside the module, transmitting the pressure of the first fluid from the pressure conversion unit to the 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] FIG. 3 is a diagram illustrating an example in which the configuration is partially different from that of 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, there are disposed a holding unit 12 that holds the surface pressure of the stacked cells 11, and a pressure conversion unit 13. The holding unit 12 uses a first fluid as a working fluid. The electric pump 2 uses a second fluid as a working fluid. The pressure conversion unit 13 converts the pressure of the second fluid into the pressure of the first 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 air pressure (pressure of the second fluid) from the electric pump 2 to the pressure conversion unit 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 used to return the air (second fluid) coming out of the pressure conversion unit 13 to the electric pump 2, and a branch pipe 41 leading to the second piping 4 is connected to the pressure conversion unit 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 a stacked cell 11 is arranged in the upper part of the housing 10. The stacked cell 11 is installed on a support plate 111. A pair of two holding parts 12 and one pressure conversion part 13 are arranged in the space below the housing 10 (the space below the support plate 111).

[0019] The 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 pressure conversion unit 13 is located in the center of the lower space of the housing 10, and the two holding units 12 are located on either side of the pressure conversion unit 13 in the long side direction when viewed in plan of the rectangular parallelepiped that forms the housing 10.

[0021] The pressure conversion unit 13 is composed of a reducer made of a wave gear and a vane-type hydraulic pump. The input shaft of the reducer is driven by compressed air supplied from a branch pipe 31 of the first piping 3, and the output shaft of the reducer drives the hydraulic pump.

[0022] Within the housing 10, the outlet of the hydraulic pump of the pressure conversion unit 13 and the high-pressure hydraulic chambers 12a of the two hydraulic cylinders (holding units 12) are connected by piping (internal flow paths) 14. Also installed are a reserve tank 15, a piping 16 that connects the low-pressure hydraulic chambers 12b and the reserve tank 15, and a piping 17 that connects the hydraulic pump of the pressure conversion unit 13 and the reserve tank 15. These pipings are omitted from Figure 2.

[0023] As described above, the all-solid-state battery 100 of this embodiment has a cell surface pressure holding mechanism including the holding unit 12, the electric pump 2, the pressure conversion unit 13, the external flow path (first piping 3), and the internal flow path (piping 14).

[0024] 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 pressure conversion unit 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]

[0025] The cell surface pressure maintaining mechanism of this embodiment operates as follows.

[0026] 4, when the stacked cells 11 are contracted, the electric pump 2 is driven to supply compressed air to the first pipe 3. At that time, if all the modules 1 are to be operated, all the on-off valves 32 are opened. Accordingly, the compressed air supplied from the electric pump 2 to the first pipe 3 is supplied to the pressure conversion unit 13 from the branch pipes 31 of each module 1.

[0027] In the pressure conversion unit 13, the input shaft of the reducer is driven by compressed air supplied from the branch pipe 31, and the output shaft of the reducer drives the hydraulic pump. At this time, oil is supplied to the hydraulic pump of the reducer from a reserve tank 15. Then, oil in the hydraulic pump is supplied to the high-pressure hydraulic chambers 12a of the two hydraulic cylinders (holding unit 12) through piping 14. As a result, the pistons 122 are pushed up by the hydraulic pressure, and some of the oil in the low-pressure hydraulic chambers 12b is returned to the reserve tank 15 through piping 16. This allows the contracted laminated cells 11 to be held at an appropriate surface pressure.

[0028] When the laminated cell 11 expands as shown in Fig. 5, the electric pump 2 is stopped, and the hydraulic pump of the reducer that constitutes the pressure conversion unit 13 is stopped. As a result, the oil in the high-pressure hydraulic chamber 12a is returned to the reserve tank 15. Furthermore, oil is supplied from the reserve tank 15 to the low-pressure hydraulic chamber 12b, causing the piston 122 to descend. This allows the expanded laminated cell 11 to be maintained at an appropriate surface pressure. [Action, effect]

[0029] According to the cell surface pressure holding mechanism of this embodiment, air pressure (pressure of the second fluid) is converted into hydraulic pressure (pressure of the first fluid) by the pressure conversion unit 13, and the holding unit 12 transmits the load to the support plate 111 using only hydraulic pressure to hold the surface pressure of the stacked cell 11. This makes it possible to make the device smaller than when the load is transmitted to the support plate 111 separately using the pressures of two types of fluid.

[0030] In addition, since the pressure is increased in two stages, by the electric pump 2 placed outside the module 1 and the pressure conversion unit 13 placed inside the module 1, the hydraulic pressure (pressure of the first fluid) in the holding unit 12 can be increased while the electric pump 2 and the piping 3, 4 can be made smaller and lighter.

[0031] Furthermore, noise becomes a problem when high pressure is generated only by an electric pump placed outside the module, but in the cell surface pressure holding mechanism of this embodiment, high pressure is generated in the holding section 12 by the pressure conversion section 13 placed inside the sealed module 1, thereby making it possible to reduce noise.

[0032] Furthermore, if high pressure is achieved only by an electric pump located outside the module, the electric pump located outside the module will be large because it needs to pump fluid energy to multiple modules.In contrast, the cell surface pressure maintaining mechanism of this embodiment increases pressure in two stages: by the electric pump 2 located outside the module 1 and the pressure conversion unit 13 located inside the module 1, so it is possible to avoid increasing the size of the electric pump located outside the module.

[0033] Furthermore, since the retaining portion 12, which uses oil (first fluid) as the working fluid, is disposed inside the module 1, oil leakage to the outside of the module 1 can be prevented.

[0034] Furthermore, since a hydraulic cylinder is used as the holding portion 12, the oil sealing performance is improved and the decrease in cell surface pressure during holding can be suppressed.

[0035] 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, which allows for compactness.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 FIG. 6 shows an example (second embodiment) in which a compression spring 5 is installed inside the high-pressure hydraulic chamber 12a of the holder 12. Other than this, it is the same as the example (first embodiment) of FIG. 2. That is, the example of FIG. 6 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 holder 12, can be made to follow the position of the stacked cells 11 during operation, eliminating the need for hydraulic control of the holder 12. Furthermore, while the hydraulic pressure of the hydraulic holding mechanism of the holder 12 may drop during the contraction process of the stacked cells 11, the inclusion of the compression spring 5 ensures that the holding force can be maintained even if the hydraulic pressure temporarily drops. [Each aspect and its effects] <First aspect>

[0036] A first aspect of the present invention is a cell surface pressure holding mechanism including: (1) a holding unit disposed inside a module storing stacked cells of an all-solid-state battery, the holding unit holding the surface pressure of the stacked cells using a first fluid as a working fluid; (2) an electric pump disposed outside the module, the electric pump using a second fluid as a working fluid; (3) a pressure conversion unit disposed inside the module, converting the pressure of the second fluid into the pressure of the first fluid; (4) an external flow path disposed outside the module, transmitting the pressure of the second fluid from the electric pump to the pressure conversion unit; and (5) an internal flow path disposed inside the module, transmitting the pressure of the first fluid from the pressure conversion unit to the holding unit.

[0037] According to the cell surface pressure holding mechanism of the first aspect, the pressure of the second fluid is converted into the pressure of the first fluid by the pressure conversion unit, and the holding unit transmits the load using only the pressure of the first fluid to hold the surface pressure of the stacked cells, which makes it possible to make the device smaller than when the load is transmitted separately using the pressures of two types of fluid.

[0038] In addition, the pressure is increased in two stages, by the electric pump placed outside the module and the pressure conversion unit placed inside the module, so the electric pump and external flow path can be made smaller and lighter while increasing the pressure of the first fluid in the holding unit.

[0039] Furthermore, noise becomes an issue when high pressure is generated only by an electric pump located outside the module, but the cell surface pressure retention mechanism of the first embodiment can reduce noise by generating high pressure in the retention section using a pressure conversion section located inside the sealed module.

[0040] Furthermore, if high pressure is achieved only by an electric pump located outside the module, the electric pump located outside the module will be large because it needs to pump fluid energy to multiple modules.In contrast, the cell surface pressure retention mechanism of the first aspect increases pressure in two stages: by the electric pump located outside the module and the pressure conversion unit located inside the module, so it is possible to avoid increasing the size of the electric pump located outside the module.

[0041] Since the holding portion using the first fluid as the working fluid is disposed inside the module, leakage of the first fluid to the outside of the module can be prevented.

[0042] Furthermore, if the viscosity of the working fluid is low, leakage occurs during holding, resulting in problems of energy consumption and operating noise in order to maintain a constant pressure, and ensuring leakage does not pose problems of increased space, cost, and durability for the leak prevention mechanism. On the other hand, if the viscosity of the working fluid is high, problems arise such as increased operating energy due to viscous resistance, a larger fluid pump, and increased size and weight due to an increased flow path diameter. Therefore, by changing the working fluid between the holding section and the pressure conversion section (first fluid, second fluid), for example, using a low-viscosity fluid in the pressure conversion section and a high-viscosity fluid in the holding section, it is possible to reduce energy consumption in both sections while making them smaller and quieter.

[0043] The second fluid is used in a location where the fluid that communicates the inside and outside of the module can be easily replaced, so that an inexpensive fluid that is readily distributed can be used as the second fluid.

[0044] The second fluid has an external flow path disposed outside the module as a pressure transmission path, so that the second fluid can be exchanged outside the module.

[0045] 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.

[0046] 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>

[0047] 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.

[0048] 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 pressure conversion unit 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.

[0049] Furthermore, the viscous resistance of the electric pump is reduced, allowing the electric pump to be made smaller.

[0050] 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.

[0051] 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.

[0052] The retaining part is the part that receives the load from the stacked cells, and the lubrication of the sliding part is strict. However, by using a first fluid with a high kinetic viscosity as the working fluid of the retaining part, the lubricating film on the sliding part is less likely to break, and durability is improved. <Third mode>

[0053] 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.

[0054] The low bulk modulus of the first fluid (working fluid in the holding portion) reduces the temperature rise caused by compression of the first fluid in the holding portion, and prevents a decrease in viscosity due to a temperature rise and leakage due to a decrease in viscosity.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] Because the second fluid has a high bulk modulus, when the electric pump is operated temporarily, the second fluid can be maintained under pressure in the piping, so that the pressure does not drop immediately and the response delay in starting the pressure conversion to the first fluid can be reduced the next time the electric pump is started. <Fourth aspect>

[0060] In a fourth aspect, in the cell surface pressure retaining mechanism of the first aspect, the heat of the second fluid is dissipated by an external flow path (a flow path that transmits the pressure of the second fluid from the electric pump to the pressure conversion unit).

[0061] The cell surface pressure retention mechanism of the fourth aspect eliminates the need for a temperature control device for the second fluid, thereby enabling the electric pump to be made smaller. Furthermore, the compressed second fluid is cooled as it passes through the flow path from the electric pump to each module, thereby preventing the temperature rise inside the module due to the first fluid (working fluid in the retention section). <Fifth aspect>

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

[0063] According to the cell surface pressure retention mechanism of the fifth aspect, at low temperatures, the temperature regulator increases the temperature of the second fluid in the external flow path 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. <Sixth mode>

[0064] A sixth aspect is the cell surface pressure retaining mechanism of the first aspect, in which the first fluid (working fluid of the retaining portion) is oil, and the second fluid (working fluid of the pressure converting portion) is air.

[0065] According to the cell surface pressure retaining mechanism of the sixth aspect, the following effects can be obtained.

[0066] Since oil viscosity increases at low temperatures, oil can be held stably without leaks by using hydraulic pressure.

[0067] 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.

[0068] Since the oil usage is contained within the module, oil leakage to the outside of the module can be avoided.

[0069] The first fluid is almost stationary in the 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.

[0070] Since the working fluid of the pressure converter is air, the pressure converter can be driven by a highly efficient air motor at low temperatures, making it possible to reduce the operating energy at low temperatures.

[0071] Because the working fluid in the pressure converter is air, which has a lower viscosity than oil, the viscous resistance of the pressure converter can be reduced and the 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 pressure converter can increase the temperature rise effect caused by compression by the electric pump.

[0072] Since the working fluid in the pressure converter is air, there is no environmental impact even if a leak occurs from the flow path, and since there is no need for a leak recovery section, the device can be made smaller.

[0073] When air is used as the working fluid for the holding part, the influence of pressure changes due to temperature changes is large, but by using oil, the influence of temperature can be reduced.

[0074] By using compressed air as the working fluid (working energy source) in the pressure converter, the pressure change is small even if there is a change in the temperature of the air on the intake side of the compressed air pump, so the impact on the generated pressure is small.

[0075] By using compressed air as the working fluid (source of working energy) in the pressure conversion unit, compressed air can be efficiently generated by using the pressure of the wind from the vehicle when it is running and increasing the inlet pressure of the compressed air pump when the vehicle is in motion and an increase in working energy is required.

[0076] By converting air pressure into hydraulic pressure and then maintaining it with hydraulic pressure, the cell surface pressure can be maintained by closing the valve in the hydraulic path. <Seventh mode>

[0077] In a seventh aspect, in the cell surface pressure retaining mechanism of the sixth aspect, the electric pump is a compressed air pump, the pressure conversion unit has an inlet passage for compressed air from the compressed air pump and an outlet passage for compressed air, the inlet passage is provided with a check valve, and the outlet passage is open to the atmosphere.

[0078] According to the cell surface pressure retaining mechanism of the seventh aspect, the following effects can be obtained.

[0079] In the cell surface pressure retention mechanism of the sixth 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 seventh 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.

[0080] 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. <Eighth aspect>

[0081] An eighth aspect is the cell surface pressure holding mechanism of the sixth aspect, which includes a passive cell surface pressure applying mechanism inside the hydraulic pressure holding mechanism that constitutes the holding portion.

[0082] 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 the piston rod portion of a hydraulic cylinder can be given. By having this configuration, the cell surface pressure maintaining mechanism of the eighth aspect can obtain the following effects.

[0083] During operation, the piston of the hydraulic cylinder in the holding section can be made to follow the position of the stacked cells, eliminating the need for hydraulic control in the holding section. Furthermore, while the hydraulic pressure in the hydraulic holding mechanism of the holding section 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. <Ninth aspect>

[0084] A ninth aspect is the cell surface pressure retaining mechanism of the sixth aspect, which includes, as the retaining portion, a hydraulic cylinder or a screw mechanism portion which includes a screw mechanism portion driven by a hydraulic motor and a reducer.

[0085] According to the cell surface pressure retaining mechanism of the ninth aspect, the following effects can be obtained.

[0086] When a hydraulic cylinder is used as the holding part, the oil sealing performance is improved and the decrease in cell surface pressure during holding can be suppressed.

[0087] If a screw mechanism driven by a hydraulic motor and a reducer is used as the holding unit, it is possible to convert small air pressure into large hydraulic pressure, allowing the compressed air motor to be made smaller. The first embodiment corresponds to an example in which a hydraulic cylinder is used as the holding portion in the ninth aspect. <Another Example 1>

[0088] Another aspect is a cell surface pressure retaining mechanism including: a retaining unit that is disposed inside a module storing laminated cells of an all-solid-state battery and retains the surface pressure of the laminated cells using a first fluid as a working fluid; and an electric pump that is disposed outside the module and uses a second fluid as a working fluid, wherein the first fluid (working fluid of the retaining unit) and the second fluid (working fluid of the electric pump) are the same fluid; and a mechanism that makes the temperature of the second fluid higher than that of the first fluid by a temperature rise of the second fluid that occurs during compression by the electric pump or by the second fluid recovering heat generated from the electric pump.

[0089] In this case, since the first fluid and the second fluid are the same fluid, the pressure of the second fluid can be directly transmitted to the first fluid, eliminating the need for a pressure conversion mechanism and enabling miniaturization.Furthermore, by sharing a flow path for recovering leaks of the first fluid and the second fluid, miniaturization is also possible. <Another aspect 2>

[0090] By providing a single air pressure pump as the hydraulic drive source for multiple modules, and by stopping the actuators of other modules when the actuators of one module are driven, the maximum output of the electric pump can be reduced, making the electric pump smaller, and by reducing the maximum output, it is possible to prevent the motor from overheating. <Another aspect 3>

[0091] When the laminated cells expand, the high-pressure oil in the hydraulic cylinder is returned to the hydraulic pump, causing the hydraulic pump and air motor to rotate in the opposite direction, increasing the pressure of the compressed air. The increased compressed air is then used to rotate the air pump in the opposite direction, generating electricity. This reduces the maximum output of the electric pump, making it possible to make the electric pump smaller, and by reducing the maximum output, it is possible to prevent the motor from overheating. <Another Example 4>

[0092] Each battery module is equipped with a hydraulic pressure retention mechanism, and each hydraulic pressure retention mechanism has multiple hydraulic cylinders. If one of the hydraulic cylinders fails, the remaining functioning hydraulic cylinders will maintain the cell surface pressure, making it possible to maintain a minimum surface pressure and maintain cell function even when some of the hydraulic cylinders fail.

[0093] When some cylinders are malfunctioning, the maximum oil pressure of the normal hydraulic cylinders is set to be higher than the maximum oil pressure when all hydraulic cylinders are normal. This increases the oil pressure of the remaining cylinders in the event of a malfunction, making it possible to maintain the minimum cell surface pressure necessary to charge and discharge the battery. <Another Example 5>

[0094] The system is equipped with multiple battery modules, each equipped with a fluid pressure retention mechanism, and allows the fluid pressure retention chambers of the cell surface pressure retention mechanisms between modules to communicate with each other, so that if excessive pressure occurs in a specific module, the working fluid will flow out to the other modules. This provides the following effects:

[0095] It is possible to reduce the pressure in the excessive module. Because the structure does not release high-pressure fluid to the outside, if the excessive pressure release valve fails, it is possible to prevent a drop in cell surface pressure due to fluid leaking out. In addition, because there is no external fluid leakage, there is no need for a recovery unit for the leaked fluid. Furthermore, because fluid can be communicated between multiple modules, even if the pressure generating unit of one module fails, the cell surface pressure can be maintained by receiving pressure from the other normal modules. Furthermore, although the pressure in the other modules increases, the increase is only a fraction of the excessive pressure in the module, so it is within the allowable pressure range, and the other modules can use the received pressure to maintain the pressure.

[0096] By providing an on-off valve in the communication passage between modules, if one module fails and excessive pressure occurs, the on-off valve can be opened to release the excess pressure to the other modules, reducing the excess pressure; if one module fails and underpressure occurs, the on-off valve can be closed to prevent a drop in pressure in the other modules. [Explanation of symbols]

[0097] 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 Holding section (hydraulic cylinder), 13 Pressure conversion 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 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; an electric pump that uses the second fluid as a working fluid and is disposed outside the module; a pressure converter disposed inside the module and converting the pressure of the second fluid into the pressure of the first fluid; an external flow path disposed outside the module, which transmits the pressure of the second fluid from the electric pump to the pressure converter; an internal flow path disposed inside the module, the internal flow path transmitting the pressure of the first fluid from the pressure conversion unit to the holding unit; 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. The cell surface pressure maintaining mechanism according to claim 1 , wherein the second fluid dissipates heat through the external flow path.

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

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

7. 7. The cell surface pressure retaining mechanism according to claim 6, wherein the electric pump is a compressed air pump, the pressure conversion unit includes an inlet passage for compressed air from the compressed air pump and an outlet passage for compressed air, the inlet passage is provided with a check valve, and the outlet passage is open to the atmosphere.

8. 7. The cell surface pressure holding mechanism according to claim 6, further comprising a passive cell surface pressure applying mechanism provided inside the hydraulic pressure holding mechanism that constitutes the holding portion.

9. 7. The cell surface pressure holding mechanism according to claim 6, wherein the holding portion comprises a hydraulic cylinder or a screw mechanism portion driven by a hydraulic motor and a reducer.

Images