Energy storage container micro-positive pressure maintaining device

Abstract

The application discloses a kind of energy storage container micro-positive pressure maintaining device, it is applied to energy storage equipment environmental control technical field, comprising: air inlet valve assembly, set in the air inlet passage of energy storage container, including temperature response drive element, the temperature response drive element is displaced, deformed or state change in response to external environmental temperature change, to open or close air inlet passage, so that external gas enters energy storage container;Air outlet valve assembly is set in the air outlet passage of energy storage container, including pressure response drive element, the pressure response drive element is displaced, deformed or state change in response to internal pressure change of the energy storage container, to open or close the air outlet passage, so that internal gas is discharged;Wherein, the temperature response drive element and the pressure response drive element are all passive drive elements, to maintain the micro-positive pressure state in the energy storage container.This device does not need external power supply, and micro-positive pressure can be continuously maintained under power-off condition.

Description

Technical Field

[0001] This invention relates to the field of environmental control technology for energy storage equipment, and specifically to a micro-positive pressure maintenance device for an energy storage container. Background Technology

[0002] With the development of new energy storage technologies, containerized energy storage systems are widely used in grid energy storage, industrial and commercial energy storage, and new energy supporting energy storage scenarios due to their high integration, convenient transportation, and flexible installation. The energy storage container integrates battery packs, battery management systems, and heat dissipation equipment, making it highly sensitive to environmental humidity. When external humid air infiltrates and condenses on the surfaces of electrical components, it can lead to a decrease in insulation resistance, a shortened creepage distance, and electrochemical corrosion of metal components. Therefore, in engineering practice, the internal pressure of the energy storage container is typically maintained at a slightly positive pressure state, 5 Pa to 50 Pa higher than the external pressure, to prevent the uncontrolled infiltration of external air.

[0003] Existing micro-positive pressure maintenance solutions mainly employ active environmental control systems, equipped with fans, compressors, or electric heating devices, and rely on pressure sensors, temperature and humidity sensors, and controllers to achieve closed-loop regulation. While these solutions can effectively maintain micro-positive pressure when the main power supply is normal, they have the following drawbacks: when the main power supply to the energy storage container is interrupted, such as during transportation or standby, the active environmental control system shuts down, causing the micro-positive pressure inside the container to disappear rapidly and the risk of condensation to increase sharply; electronic sensors and controllers are prone to failure in high-temperature, high-humidity, and vibration environments, limiting long-term reliability; and the active system requires continuous power consumption, resulting in unnecessary standby power consumption in standby or transportation scenarios.

[0004] Therefore, there is an urgent need for an energy storage container voltage stabilization device that does not require external power supply and can continuously maintain a slightly positive pressure in the event of a power outage. Summary of the Invention

[0005] This invention aims to solve the problems of existing energy storage container micro-positive pressure maintenance methods that rely on external power supply, cannot continue to work after power failure, and have complex structures. It provides an energy storage container micro-positive pressure maintenance device that does not require external energy drive and uses temperature and pressure changes to achieve automatic gas replenishment and depressurization.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] A micro-positive pressure maintenance device for an energy storage container, comprising:

[0008] An air intake valve assembly is disposed at the air intake channel of the energy storage container, including a temperature-responsive drive element. The temperature-responsive drive element responds to changes in the external ambient temperature by displacement, deformation, or state change to open or close the air intake channel, allowing external gas to enter the energy storage container.

[0009] An exhaust valve assembly is disposed at the exhaust channel of the energy storage container, including a pressure-responsive drive element. The pressure-responsive drive element responds to changes in the internal pressure of the energy storage container by displacement, deformation, or state change to open or close the exhaust channel and allow internal gas to be discharged.

[0010] Both the temperature-responsive drive element and the pressure-responsive drive element are passive drive elements, in order to maintain a slightly positive pressure state inside the energy storage container.

[0011] Optionally, the temperature-responsive driving element includes a temperature shape memory alloy valve plate, which deforms in response to changes in the external ambient temperature to open or close the air intake passage.

[0012] Optionally, the temperature shape memory alloy valve plate is made of a low-temperature shrinkage shape memory alloy;

[0013] When the external ambient temperature is lower than the first preset temperature, the temperature shape memory alloy valve plate deforms and opens the air intake channel;

[0014] When the external ambient temperature is higher than the second preset temperature, the temperature shape memory alloy valve plate restores its shape and closes the air intake channel;

[0015] The second preset temperature is greater than the first preset temperature.

[0016] Optionally, the pressure-response driving element includes a stress-shaped memory alloy valve plate, which generates a stress-induced phase change in response to pressure changes inside the energy storage container, and deforms through the phase change to open or close the exhaust passage.

[0017] Optionally, the stress shape memory alloy valve plate is made of a stress-responsive shape memory alloy;

[0018] When the internal pressure of the energy storage container reaches the first preset pressure threshold, the stress shape memory alloy valve plate deforms and opens the exhaust channel;

[0019] When the internal pressure of the energy storage container drops below the second preset pressure threshold, the stress shape memory alloy valve plate resets and closes the exhaust channel;

[0020] Wherein, the first preset pressure threshold is greater than the second preset pressure threshold.

[0021] Optionally, the stress shape memory alloy valve plate includes a pressure sensing part, a stress concentration part, and a shape memory deformation part;

[0022] The pressure sensing unit is used to withstand the gas pressure inside the energy storage container;

[0023] The stress concentration section is connected between the pressure sensing section and the shape memory deformation section, and is used to convert the pressure action into localized concentrated stress acting on the shape memory deformation section;

[0024] When the localized concentrated stress reaches the phase transition triggering condition of the shape memory deformation part, the shape memory deformation part undergoes deformation.

[0025] Optionally, the stress concentration part is a cross-sectional reduction structure, and the stress-bearing cross-sectional area of ​​the cross-sectional reduction structure is smaller than the stress-bearing area of ​​the pressure sensing part, so as to amplify the stress acting on the shape memory deformation part.

[0026] Optionally, the shape memory deformation part is disposed in the exhaust channel and is configured to change the opening state of the exhaust channel by radial contraction, axial movement or bending deformation when stress-induced phase transformation occurs.

[0027] Optionally, the exhaust valve assembly further includes a seal, which is fitted inside the exhaust passage of the exhaust valve assembly and has a through hole;

[0028] The shape memory deformation part is configured to seal the exhaust passage by engaging with the through hole of the sealing element when no phase change occurs.

[0029] Optionally, the temperature-responsive driving element is made of at least one of shape memory alloy, bimetallic sheet, or material that deforms with temperature changes;

[0030] The pressure-responsive drive element is made of shape memory material or pressure-responsive elastic material that can generate mechanical state transitions in response to changes in internal pressure.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] This invention enables the energy storage container to achieve internal pressure regulation without the need for a power supply, controller, and sensors by setting up an intake valve assembly and an exhaust valve assembly, and using temperature-responsive drive elements and pressure-responsive drive elements respectively to control the gas entry and exit.

[0033] Specifically, when the external ambient temperature decreases, the temperature-responsive actuator responds to the temperature change by displacing, deforming, or changing its state, opening the air intake channel and allowing external gas to enter the energy storage container. The gas entering the container is heated by the residual heat from the internal equipment, causing the internal pressure to rise due to thermal expansion. When the internal pressure reaches a set condition, the pressure-responsive actuator responds to the pressure change by displacing, deforming, or changing its state, opening the exhaust channel to release excess gas. When the internal pressure returns to the set range, the pressure-responsive actuator resets and closes the exhaust channel. Therefore, through the synergistic effect of temperature-responsive gas replenishment and pressure-responsive pressure relief, a self-sustaining pressure cycle process that requires no external energy input is formed.

[0034] Meanwhile, since both the temperature response drive element and the pressure response drive element adopt a mechanical passive response structure, they do not rely on electronic sensors, electronic control modules and actuators. Therefore, they can reduce system complexity, improve long-term operational reliability, and are suitable for working conditions such as power outages, transportation and standby of energy storage containers. Attached Figure Description

[0035] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0036] Figure 1 This is a schematic diagram of the overall structure of the energy storage container micro-positive pressure maintaining device provided in an embodiment of the present invention;

[0037] Figure 2 This is a stress-temperature characteristic curve of a phase change material provided in an embodiment of the present invention;

[0038] Figure 3 This is a schematic diagram of the structure of the exhaust valve assembly provided in an embodiment of the present invention;

[0039] Figure 4 This is a schematic diagram of the exhaust valve assembly provided in an embodiment of the present invention from another perspective;

[0040] Figure 5 This is a connection diagram of the exhaust valve assembly provided in an embodiment of the present invention;

[0041] Figure 6 This is a schematic diagram of the stress-induced phase transition propagation process provided in an embodiment of the present invention;

[0042] Figure 7This is a schematic diagram of the closed state of the cantilevered temperature shape memory alloy valve plate provided in an embodiment of the present invention;

[0043] Figure 8 This is a schematic diagram of the open state of the cantilevered temperature shape memory alloy valve plate provided in an embodiment of the present invention;

[0044] Figure 9 This is a schematic diagram of the diaphragm-type temperature shape memory alloy valve plate structure provided in an embodiment of the present invention;

[0045] Figure 10 This is a schematic diagram of the louvered temperature shape memory alloy valve plate structure provided in an embodiment of the present invention;

[0046] Figure 11 This is a schematic diagram of the air inlet arrangement provided in an embodiment of the present invention.

[0047] Explanation of reference numerals in the attached figures:

[0048] 1-Energy storage container; 11-Wall panel; 12-Air inlet; 13-Exhaust outlet; 14-Seal; 15-Fixing frame; 2-Intake valve assembly; 21-Cantilevered temperature shape memory alloy valve plate; 211-Fixed end; 212-Free end; 22-Diaphragm-type temperature shape memory alloy valve plate; 23-Louvre-type temperature shape memory alloy valve plate; 3-Exhaust valve assembly; 31-Pressure sensing part; 32-Stress concentration part; 33-Shape memory deformation part. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0050] In one specific embodiment, such as Figure 1 As shown, this invention provides a micro-positive pressure maintaining device for an energy storage container, which is applied to an energy storage container. The energy storage container 1 has wall panels 11, which enclose a substantially sealed housing space. Within this space are integrated battery pack sequences, a battery management system, and liquid-cooled piping for heat dissipation of the battery packs. Such precision electrical equipment is highly sensitive to ambient humidity: when humid external air enters the energy storage container 1 and encounters cooling, condensation occurs on the surfaces of electrical components, leading to a decrease in insulation resistance, a shortened creepage distance, and electrochemical corrosion of metal components. Therefore, in engineering practice, it is typically necessary to maintain the internal pressure of the energy storage container 1 at a micro-positive pressure state that is 5 Pa to 50 Pa higher than the external environment to effectively prevent the uncontrolled infiltration of external air.

[0051] Its pressure stabilization mechanism is as follows: when the internal pressure of the energy storage container 1 is higher than that of the external environment, the internal gas continuously leaks outward through unavoidable gaps such as door seams and cable perforations, and the outward airflow forms a physical barrier against the intrusion of external humid air; as long as the gas supply and leakage reach a dynamic balance, the internal pressure of the energy storage container 1 can be maintained at a slightly positive pressure for a long time. This device utilizes the above mechanism to organize the three processes of gas supply, pressurization, and depressurization into a self-sustaining cycle through the linkage of the intake valve assembly 2 and the exhaust valve assembly 3, so as to stabilize the internal pressure within the target range.

[0052] Specifically, such as Figure 1 As shown, the wall panel 11 has an air inlet 12 and an exhaust outlet 13. The air inlet 12 defines an air intake channel connecting the internal space of the energy storage container 1 with the external environment, and the exhaust outlet 13 defines an exhaust channel connecting the internal space of the energy storage container 1 with the external environment. The micro-positive pressure maintaining device for the energy storage container in this embodiment includes an air intake valve assembly 2 and an exhaust valve assembly 3. The air intake valve assembly 2 is located at the air intake channel of the energy storage container 1 and is used to control the entry of external gas into the energy storage container 1. The exhaust valve assembly 3 is located at the exhaust channel of the energy storage container 1 and is used to control the discharge of gas from inside the energy storage container 1.

[0053] The intake valve assembly 2 includes a temperature-responsive actuating element that responds to changes in the external ambient temperature by displacing, deforming, or changing its state to open or close the intake passage, allowing external gas to enter the energy storage container 1 when the intake passage is open. The exhaust valve assembly 3 includes a pressure-responsive actuating element that responds to changes in the internal pressure of the energy storage container 1 by displacing, deforming, or changing its state to open or close the exhaust passage, allowing internal gas to be discharged when the exhaust passage is open.

[0054] It should be noted that both the temperature-response and pressure-response drive elements are passive drive elements. Passive drive elements are those whose driving energy originates entirely from changes in the external ambient temperature or the internal pressure changes within the energy storage container 1 itself. They require no external power supply and no electronic components such as pressure sensors, temperature sensors, or controllers. Therefore, even in scenarios where the main power supply to the energy storage container 1 is interrupted during transportation or standby, this device can still spontaneously maintain a slight positive pressure internally by relying on the ambient temperature difference and residual heat from the internal equipment. This fundamentally solves the problem of the loss of positive pressure and the sharp increase in condensation risk after a power outage in existing active environmental control systems. It also avoids the drawbacks of electronic sensors, such as easy failure in high-temperature and high-humidity environments and high standby power consumption.

[0055] The two passive drive components work together to enable the device to form a self-sustaining pressure cycle based on the day-night temperature difference and the residual heat of the internal equipment: At night, in the low-temperature environment, the temperature-responsive drive component deforms and opens the air intake channel, allowing dry, cold air from outside to enter the energy storage container 1. The incoming cold air expands in volume after being heated by the residual heat of the internal equipment, thus increasing the internal pressure. When the internal pressure reaches the operating condition of the pressure-responsive drive component, it deforms and opens the exhaust channel to release pressure. After the internal pressure drops, the pressure-responsive drive component resets and closes the exhaust channel. During the day, when the ambient temperature rises, the temperature-responsive drive component resets and closes the air intake channel, maintaining a stable slightly positive pressure inside the energy storage container 1. This achieves long-term passive slightly positive pressure maintenance even under conditions of ambient temperature changes or internal heat sources.

[0056] As an optional implementation, the energy storage container 1 can be a standard 20-foot energy storage container or a large-capacity energy storage container of 40 feet or more; its heat dissipation method can be liquid cooling or air cooling, and this device is compatible with the above specifications and heat dissipation methods.

[0057] Furthermore, the specific structures of the air inlet 12 and the exhaust outlet 13 can be designed according to the volume and ventilation requirements of the energy storage container 1. For example, the air inlet 12 and the exhaust outlet 13 can be circular holes opened on the wall panel 11. Flange-shaped valve seats can be installed at both the air inlet 12 and the exhaust outlet 13. The air inlet valve assembly 2 and the exhaust valve assembly 3 are detachably installed on the wall panel 11 through their respective valve seats to facilitate later maintenance and replacement. As an alternative implementation, the air inlet 12 and the exhaust outlet 13 can also be other cross-sectional shapes such as square holes or oblong holes, and their cross-sectional areas can be determined according to the required flow capacity.

[0058] Furthermore, in a preferred embodiment, the temperature-responsive actuating element includes a temperature shape memory alloy valve plate, which deforms in response to changes in the external ambient temperature to open or close the intake passage.

[0059] Specifically, the temperature shape memory alloy valve is made of a low-temperature shrinkage shape memory alloy. When the external ambient temperature is lower than a first preset temperature, the temperature shape memory alloy valve deforms and opens the air intake channel; when the external ambient temperature is higher than a second preset temperature, the temperature shape memory alloy valve returns to its original shape and closes the air intake channel; wherein the second preset temperature is higher than the first preset temperature. By making the closing temperature threshold higher than the opening temperature threshold, a switching dead zone determined by the phase transition temperature hysteresis of the shape memory alloy is formed between the opening and closing actions, which can avoid frequent opening and closing of the air intake channel near the critical temperature and ensure the stability of the air replenishment process.

[0060] In practical implementation, the temperature shape memory alloy valve can be made of NiTiCu-based shape memory alloy, with a martensitic phase transformation start temperature of approximately -18℃, an austenitic phase transformation end temperature of approximately -8℃, and a phase transformation hysteresis bandwidth of approximately 10℃. Correspondingly, the first preset temperature can be set to -20℃, and the second preset temperature can be set to -5℃: when the ambient temperature is below -20℃, the temperature shape memory alloy valve is fully open; when the ambient temperature is in the range of -20℃ to -5℃, the temperature shape memory alloy valve is partially open, and the opening degree increases as the temperature decreases; when the ambient temperature is above -5℃, the temperature shape memory alloy valve is completely closed. Setting the phase transformation temperature range to the lower range of -20℃ to -5℃ ensures that the air intake valve assembly 2 is in a closed state within the battery rechargeable temperature range (usually above 0℃), without affecting the heating efficiency inside the energy storage container 1; on the other hand, it matches the air intake action with the low-temperature period at night in winter, realizing passive day-night temperature difference adaptive control. Of course, the specific values ​​of the first and second preset temperatures can be flexibly set according to the climatic conditions of the application scenario, and are not limited to the values ​​mentioned above. The values ​​of the preset temperatures should be adapted to the actual diurnal temperature difference in winter in the specific application area to ensure effective shutdown during the day.

[0061] As an alternative implementation, the phase change temperature range of the temperature shape memory alloy valve can also be adjusted as a whole according to the climate zone of the region of use. For example, the phase change temperature range can be shifted downward in cold regions and upward in temperate regions. As long as the second preset temperature is kept below the lower limit of the rechargeable temperature of the battery, the design requirement of the intake valve closing within the charging temperature range can be met under various climatic conditions.

[0062] In another specific embodiment of the present invention, the structural form of the temperature shape memory alloy valve plate of the intake valve assembly 2 can be selected from at least one of cantilever beam, diaphragm, or louver type, depending on the application scenario. Each of the three structural forms has its own characteristics: the cantilever beam type is simple and low-cost; the diaphragm type has good sealing performance; and the louver type has a large flow area.

[0063] Figure 7 The image shows the cantilever beam temperature shape memory alloy valve plate 21 in the closed intake passage state. Figure 8 This shows the state of its air intake passage being open. For example... Figure 7 and Figure 8As shown, one end of the cantilever beam valve plate is a fixed end 211 fixed to the valve seat, and the other end is a free end 212 covering the air intake passage. When the ambient temperature is higher than a second preset temperature, the valve plate remains straight, and the free end 212 fits against the opening of the air intake passage and blocks the air intake passage; when the ambient temperature drops below the first preset temperature, the valve plate undergoes low-temperature contraction deformation, and the free end 212 deflects away from the opening of the air intake passage, thus opening the air intake passage. In a specific example, the cantilever beam valve plate is a disc, and the air intake passage that cooperates with it is a circular hole. The cooperation of the two can provide a flow area that meets the air replenishment requirements when the valve is open.

[0064] like Figure 9 As shown, the diaphragm-type temperature shape memory alloy valve plate 22 is a thin, circular sheet with fixed edges, and has no hinges or mechanical gaps. When the ambient temperature is higher than the second preset temperature, the diaphragm remains flat and fits against the opening of the air intake channel, blocking the air intake channel; when the ambient temperature is lower than the first preset temperature, the diaphragm undergoes low-temperature shrinkage deformation and arches up as a whole, with its middle part detaching from the opening of the air intake channel, opening the air intake channel. This design has no fitting gaps, resulting in better sealing performance in the closed state, and is suitable for coastal areas, high humidity areas, and other regions with high protection requirements.

[0065] like Figure 10 As shown, the louvered temperature shape memory alloy valve 23 includes multiple parallel blades and linkage rods connecting each blade. Each blade is made of low-temperature shrinkage shape memory alloy. When the ambient temperature is lower than a first preset temperature, each blade contracts and deflects, forming ventilation gaps between the blades. External air enters the energy storage container 1 through these gaps. Since the blades are rigidly connected by linkage rods, a single set of phase deformation can drive all blades to open and close synchronously. In a specific example, there are 10 blades, each with a size of 200mm × 20mm × 0.8mm, a total ventilation area of ​​approximately 0.04m², and a natural ventilation exchange rate of 50m³ / h to 100m³ / h, suitable for the rapid pressure balancing needs of large-capacity energy storage containers of 40 feet and above.

[0066] It should be noted that the temperature-responsive actuating element is not limited to the aforementioned temperature shape memory alloy valve plate. In other embodiments, the temperature-responsive actuating element can also be made of a bimetallic strip: for example, a bimetallic strip composed of stainless steel and a high-temperature alloy, utilizing the difference in the thermal expansion coefficients of the two materials under temperature changes to generate bending deformation, bending to open the intake passage at low temperatures and resetting to close the intake passage at high temperatures; in addition, the temperature-responsive actuating element can also be made of other materials that deform with temperature changes, as long as it is a passive temperature-sensing actuation that does not require external power supply. The above alternative solutions can also achieve the technical effect of low-temperature air supply and high-temperature shutdown. In other embodiments, the temperature-responsive actuating element can also be made of thermally expanding materials, thermistoric materials, or composite materials with temperature-responsive displacement output capabilities.

[0067] In another specific embodiment of the present invention, the pressure response driving element includes a stress shape memory alloy valve plate, which generates a stress-induced phase change in response to the pressure change inside the energy storage container 1, and deforms through the phase change to open or close the exhaust passage.

[0068] Unlike traditional shape memory alloy valves that rely on temperature-induced phase transformation, the stress-induced shape memory alloy valve in this embodiment abandons temperature-driven logic. It is made of a stress-responsive shape memory alloy and relies on the mechanical load generated by internal micro-pressure to trigger stress-induced martensitic phase transformation, thereby achieving passive opening and closing based solely on pressure. Specifically, when the internal pressure of the energy storage container 1 reaches a first preset pressure threshold, the stress-induced shape memory alloy valve deforms and opens the exhaust channel; when the internal pressure of the energy storage container 1 drops below a second preset pressure threshold, the stress-induced shape memory alloy valve resets and closes the exhaust channel; wherein the first preset pressure threshold is greater than the second preset pressure threshold.

[0069] Similar to the temperature hysteresis on the intake side, stress-induced martensitic transformation also exhibits stress hysteresis: the critical stress for phase transformation on the loading path is higher than the critical stress for reverse phase transformation on the unloading path. Utilizing this characteristic, by making the opening pressure threshold (the first preset pressure threshold) higher than the closing pressure threshold (the second preset pressure threshold), a pressure dead zone is created between opening and closing, preventing the exhaust valve assembly 3 from frequently opening and closing near the critical pressure and ensuring the smoothness of the pressure stabilization process. In a specific example, the first preset pressure threshold is 30 Pa ± 10 Pa, and the second preset pressure threshold is 15 Pa, matching the micro-positive pressure engineering requirements of 5 Pa to 50 Pa for energy storage containers.

[0070] Regarding materials, the shape memory alloy used in this invention is a conventional material in existing technology, such as stress-responsive NiTi alloy. Its parameters, such as the critical stress for stress-induced martensitic transformation, can be set within a wide range through conventional alloy composition adjustment, heat treatment, and pre-strain training processes. This is common knowledge to those skilled in the art and will not be elaborated upon here. Figure 2 As shown, the critical stress for phase transformation of shape memory alloys varies with temperature. At the same temperature, the critical stress for phase transformation in the loading direction is not the same as the critical stress for reverse phase transformation in the unloading direction. The general mechanism of stress-induced phase transformation described above is the design basis for pressure-responsive drive elements. In a specific example, the tensile critical stress for phase transformation of the selected material is adjusted to the range of 200 kPa to 500 kPa to match the stress amplification structure described later.

[0071] Figure 2In the diagram, the shaded area containing the martensitic phase corresponds to a low-temperature, low-stress state. When the temperature shape memory alloy valve plate of this invention is in this phase region, it deforms and the air intake channel opens. After the temperature rises and crosses the zero-stress phase transformation line, the temperature shape memory alloy valve plate transforms into the austenitic phase, the temperature shape memory alloy valve plate resets, and the air intake channel closes.

[0072] The shaded area where the austenite phase is located corresponds to the matrix phase under normal temperature and pressure. The stress shape memory alloy valve plate of the present invention is in the austenite phase region under normal working conditions. The tensile stress generated by the micro-positive pressure inside the energy storage container 1 has not yet reached the phase transformation threshold, and the exhaust channel remains closed.

[0073] The shaded region where the stress-induced martensite phase is located: When the local stress of the stress shape memory alloy valve plate crosses the boundary line of the stress-induced phase transformation and enters this phase region, a stress-induced martensite phase transformation occurs, the stress shape memory alloy valve plate deforms, and the exhaust channel opens to release pressure; after the pressure is unloaded, it exits this phase region, undergoes a reverse phase transformation to restore the austenite phase, and the exhaust channel closes again.

[0074] It should be noted that the pressure-responsive actuating element is not limited to the stress-induced shape memory alloy valve plate described above. In other embodiments, the pressure-responsive actuating element is made of a shape memory material or a pressure-responsive elastic material capable of mechanical state transitions in response to changes in internal pressure, such as an elastic pressure relief structure combined with a diaphragm; as long as it can generate mechanical deformation to open the exhaust passage under internal pressure and does not require external power supply. Using a stress-induced phase change type shape memory alloy is a preferred embodiment of the present invention, which has advantages over elastic pressure relief structures such as stable trigger threshold, no spring fatigue drift, and resistance to alternating loads.

[0075] The core of the exhaust valve assembly 3 lies in its ability to amplify the weak internal air pressure into a localized stress sufficient to trigger a phase change through a necking structure. Its structure will be described in detail below. Figure 3 , Figure 4 , Figure 5 As shown, in a preferred embodiment, the stress shape memory alloy valve plate includes a pressure sensing part 31, a stress concentration part 32, and a shape memory deformation part 33. The pressure sensing part 31 is used to withstand the gas pressure inside the energy storage container 1; the stress concentration part 32 is connected between the pressure sensing part 31 and the shape memory deformation part 33, and is used to convert the pressure action into local concentrated stress acting on the shape memory deformation part 33; when the local concentrated stress reaches the phase change triggering condition of the shape memory deformation part 33, the shape memory deformation part 33 deforms.

[0076] Specifically, the pressure sensing unit 31, the stress concentration unit 32, and the shape memory deformation unit 33 are connected in sequence, and their axes coincide. The pressure sensing unit 31 has a plate-like, disc-like, or membrane-like structure and is positioned facing the interior of the energy storage container 1 to directly withstand the internal gas pressure. The pressure sensing unit 31 is fixed to the wall panel 11 by a fixing bracket 15, and the shape memory deformation unit 33 extends axially into the exhaust channel from the stress concentration unit 32. The slight positive pressure inside the energy storage container 1 acts on the pressure sensing unit 31 to form an overall axial force, which is concentrated and transmitted to the shape memory deformation unit 33 through the stress concentration unit 32.

[0077] During assembly, the mounting bracket 15 may include a pressure plate and connecting bolts. The pressure plate presses the edge of the pressure sensing part 31 against the mounting surface of the wall panel 11. The connecting bolts pass through the pressure plate and connect to the threaded holes on the wall panel 11, thereby fixing the stress shape memory alloy valve plate as a whole at the exhaust port 13, and the shape memory deformation part 33 extends into the exhaust channel. After assembly, the internal air pressure transmission path is as follows: the air pressure acts on the pressure sensing part 31, is transmitted and amplified through the stress concentration part 32, and finally acts on the shape memory deformation part 33. The force transmission path is short and along the same axis, avoiding jamming caused by off-center loading.

[0078] Furthermore, the thickness of the pressure sensing part 31 can be determined according to its diameter and the required stiffness. For example, in the example of a circular pressure-bearing surface with a diameter of 25mm, its thickness can be 0.3mm to 1mm. This ensures that no significant bending deflection occurs under the action of internal air pressure, allowing the force to be completely transmitted axially to the stress concentration part 32, while avoiding increased material costs and overall weight due to excessive thickness. A reinforcing rib can also be provided on the side of the pressure sensing part 31 facing away from the interior of the energy storage container 1 to further improve its bending stiffness.

[0079] Furthermore, the stress concentration section 32 is a cross-sectional reduction structure. The force-bearing cross-sectional area of ​​the cross-sectional reduction structure is smaller than that of the pressure sensing section 31, thereby amplifying the stress acting on the shape memory deformation section 33. The pressure sensing area and the reduction area form an area amplification, which, combined with geometric stress concentration, achieves micro-pressure triggering. Its amplification mechanism includes two-stage coupling: the first stage is area amplification gain, where the average stress at the cross-section of the cross-section reduction structure satisfies... Where P represents the slight positive pressure inside energy storage container 1. The pressure sensing area of ​​the pressure sensing unit 31 is the area under which the force is received. The first level represents the cross-sectional area of ​​the reduced-section structure under stress; the second level represents the geometric stress concentration gain, where the local peak stress at the root of the reduced-section structure satisfies... Where Kt is the stress concentration factor corresponding to the necking structure. In other words, the internal air pressure first converges into an overall force on the larger pressure sensing part 31, and then is concentrated into a local peak stress much higher than the average value on the small necking section. The weak air pressure is thus amplified into a stress level sufficient to drive the phase change.

[0080] In a specific example, the pressure sensing part 31 is a circular pressure-bearing surface with a diameter of 25mm, and the force-bearing area is... Approximately 490 mm²; the necking diameter of the cross-section reduction structure is 0.25 mm, and the stress-bearing cross-sectional area is... Approximately 0.049 mm², area ratio It is approximately 10,000 times greater. Under the maximum working micro-positive pressure condition of 50 Pa, through the coupling effect of area amplification and conventional microstructure stress concentration, the directional tensile peak stress generated at the necking position can reach the level of 10 MPa, which is far higher than the material's phase transformation critical tensile threshold of 200 kPa to 500 kPa. The triggering margin is sufficient and the operation is stable; moreover, there is no need to pursue an ultra-high stress concentration factor, the structural parameters are reasonable and the engineering processability is good.

[0081] In another embodiment, the pressure sensing unit 31 is a circular diaphragm with fixed edges, and a cross-sectional reduction structure is disposed at the center of the diaphragm. In a specific example, the diaphragm diameter is 32 mm, and the force-bearing area A1 is approximately 804 mm²; the diameter of the central reduction zone is 0.28 mm, and the force-bearing cross-sectional area A1 is... s The area is approximately 0.0615 mm², with an area ratio of approximately 13,000. Internal air pressure acts uniformly on the entire pressure-bearing surface of the diaphragm, generating axial thrust. This thrust, concentrated through the central necking, can cause local peak stress to reach the material's phase transformation threshold under a low pressure of 20 Pa. The theoretical opening pressure is approximately 20 Pa. The arrangement of the entire diaphragm under pressure and concentrated at the central necking results in uniform stress distribution and eliminates the need for moving hinges, making it suitable for applications requiring higher trigger sensitivity.

[0082] The stress-induced martensitic transformation of shape memory alloys exhibits a stress concentration-preferred nucleation characteristic: the transformation first occurs at the location of the highest local stress and then spreads globally due to the internal stress gradient. For example... Figure 6As shown, the phase change propagation process of this device is as follows: internal micro-pressure generates a uniform load on the pressure sensing unit 31, which is concentrated through the cross-sectional reduction structure to form the average stress of the cross-section; the abrupt change of the necked cross-section generates geometric stress concentration, causing the local peak stress to reach the critical value of phase change first; the phase change preferentially nucleates at the stress concentration location and forms a phase change front; the phase change front continues to diffuse to the entire shape memory deformation unit 33 under the drive of the stress gradient; after the phase change is completed in the whole domain, macroscopic deformation is generated, realizing the opening of the exhaust channel to relieve pressure. It can be seen that this device does not simply rely on the area ratio to amplify the average stress, but combines the amplification of area force with geometric stress concentration, amplifying the weak pressure difference of 5Pa to 50Pa to the peak stress level that satisfies the phase change, thus solving the problem that conventional shape memory alloy valve plates cannot respond to extremely low micro-pressures.

[0083] In terms of fabrication, the aforementioned reduced-section structure is a conventional precision micro-notch structure, requiring no nanoscale extreme processing. It can be mass-produced using mature industrial processes such as femtosecond laser micromachining and precision chemical etching. Its stress concentration factor Kt has no universal lookup table parameter and can be obtained through finite element static mechanical simulation calibration, a common technique for stress design of mechanical microstructures. Simultaneously, this structure avoids the defects of easy fracture and fatigue failure in ultra-thin walls, exhibiting high structural strength and long-term adaptability to the alternating gas pressure conditions of energy storage container 1. Furthermore, since stress-induced phase transitions only respond to directional tensile stress fields, conventional mechanical extrusion and static pressure loads cannot meet the mechanical conditions for phase transitions, thus avoiding the risk of accidental triggering during assembly and maintenance.

[0084] Furthermore, the axial dimensions of the cross-section reduction structure also need to be designed appropriately: if the axial length of the necking section is too short, the local stress gradient will be too large, and the propagation driving force to the shape memory deformation section 33 after phase transformation nucleation will be insufficient; if the length is too long, the necking section itself will bear a large amount of deformation, reducing the overall stiffness and increasing the risk of fracture. In a specific example, the axial length of the necking section is 2 to 5 times its diameter. For example, when the necking diameter is 0.25 mm, the axial length can be 0.5 mm to 1.2 mm. The transition position between the necking section and the pressure sensing section 31 and the shape memory deformation section 33 can be set with rounded corners to control the stress concentration within the necking section range and avoid unexpected stress peaks at the transition position that could cause the nucleation position to shift.

[0085] As an alternative implementation, the shape of the pressure sensing part 31 is not limited to a circle, but can also be square, elliptical, etc., and its area is determined according to the required force. The cross-sectional shape of the cross-section reduction structure can be circular, slit-shaped, polygonal, etc. The number of cross-section reduction structures can be one or multiple evenly distributed along the circumference, so as to improve the symmetry and uniformity of the structure while ensuring the stress concentration effect.

[0086] In yet another specific embodiment of the present invention, such as Figure 3 and Figure 4 As shown, the shape memory deformation part 33 is disposed in the exhaust channel and is configured to change the opening state of the exhaust channel by means of radial contraction, axial movement or bending deformation when stress-induced phase transformation occurs.

[0087] In one embodiment, the shape memory deformation part 33 is fitted inside the exhaust channel of the exhaust valve assembly 3 and is configured to contract radially when a stress-induced phase transition occurs to open the exhaust channel.

[0088] Specifically, the exhaust valve assembly 3 also includes a seal 14, which is fitted inside the exhaust channel of the exhaust valve assembly 3 and has a through hole. The shape memory deformation part 33 is configured to seal and cooperate with the through hole of the seal 14 when no phase change occurs, so as to close the exhaust channel. Thus, the exhaust valve assembly 3 constitutes a normally closed overpressure relief valve. Its complete working process is as follows: Under normal conditions, the outer wall of the shape memory deformation part 33 is sealed and fitted with the through hole wall of the seal 14. The gap between the two is extremely small and can be regarded as no airflow. The exhaust channel is in a closed state, and the slight positive pressure inside the energy storage container 1 is maintained. When the internal pressure reaches the first preset pressure threshold, the shape memory deformation part 33 undergoes a stress-induced phase change and contracts radially. A ventilation gap is formed between it and the through hole of the seal 14, the exhaust channel is opened, and the internal gas is discharged and depressurized through the exhaust port 13. When the internal pressure drops below the second preset pressure threshold, the shape memory deformation part 33 undergoes a reverse phase change and recovers radially, re-sealing and cooperating with the through hole of the seal 14, and the exhaust channel is closed again. This forms a complete opening and closing cycle: normally closed, open under overpressure, depressurize and reset, and then close again.

[0089] In a specific implementation, the seal 14 can be made of an annular bushing of elastic sealing material such as silicone rubber or fluororubber and embedded in the inner wall of the exhaust channel; the shape memory deformation part 33 is columnar to match the through hole, and its outer diameter forms a sealing fit with the inner diameter of the through hole with a predetermined interference amount in the un-phase-change state.

[0090] Furthermore, the seal 14 and the inner wall of the exhaust passage can be an interference fit or a snap fit, so that the seal 14 can be replaced separately after long-term use and aging, without having to replace the entire exhaust valve assembly 3, thereby reducing the maintenance cost over the entire life cycle.

[0091] In another specific embodiment of the present invention, such as Figure 11 As shown, the installation position of the air intake valve assembly 2 can be flexibly selected according to the airflow organization and heat dissipation scheme inside the energy storage container 1. For example, the air intake valve assembly 2 can be arranged on the top wall, the middle of the side wall, or the bottom of the energy storage container 1: the top wall arrangement is suitable for both liquid cooling and air cooling schemes; the middle side wall arrangement is also universal; the bottom side wall arrangement is suitable for cold regions in winter, and can utilize the characteristic of cold air sinking to enhance the air replenishment effect.

[0092] For air-cooled energy storage containers, preferably, the air inlet valve assembly 2 is located inside the energy storage container 1 on the side near the air conditioning outlet and within the air conditioning airflow coverage area. During heating operation, the hot airflow from the air conditioning outlet can quickly raise the temperature of the shape memory alloy valve plate, causing it to close promptly and blocking the continuous entry of low-temperature air, thus balancing voltage stabilization and heating efficiency. For liquid-cooled energy storage containers, there is no air conditioning inside the energy storage container 1. The battery's temperature rise mainly relies on self-heating during charging and discharging or the heating function of the liquid cooling system. The amount of cold air introduced by the air inlet valve assembly 2 is limited. Through the cross-sectional design of the air inlet channel, the airflow can be controlled between 0.1 m³ / h and 0.5 m³ / h. Compared to the tens of cubic meters of air volume and equipment heat capacity inside the energy storage container 1, its impact is negligible.

[0093] Furthermore, the exhaust valve assembly 3 is located in the area above the side wall of the energy storage container 1 to improve exhaust efficiency by utilizing the natural rising characteristics of hot air; when located at the top, the exhaust valve assembly 3 is equipped with a protective structure on its outer side to reduce the risk of rain and snow entering.

[0094] It should also be noted that the timing of the intake and exhaust valves is ensured through a staggered configuration of temperature windows: the phase change temperature range of the temperature shape memory alloy valve plate (e.g., -20℃ to -5℃) is lower than the normal operating temperature range of the stress shape memory alloy valve plate, thus allowing the intake valve assembly 2 and exhaust valve assembly 3 to operate sequentially according to changes in ambient temperature and internal pressure, without interference, avoiding conflict between the two valves under the same operating conditions. Simultaneously, through the reasonable configuration of temperature and pressure response ranges, the intake valve assembly 2 and exhaust valve assembly 3 operate sequentially according to different triggering conditions, preventing simultaneous opening and pressure regulation failure.

[0095] Taking a liquid-cooled energy storage container in northern winters as an example, the ambient temperature at night is -15℃, and the residual heat from the internal equipment keeps the internal temperature at approximately 25℃. A complete working cycle of this device is as follows: At night, when the ambient temperature is between the first and second preset temperatures, the temperature shape memory alloy valve is partially open, and dry, cold air is introduced into the energy storage container 1. The introduced cold air is heated to approximately 25℃ by the residual heat from the equipment, expanding in volume by approximately 14%, and the internal pressure rises to approximately 35Pa. After reaching the first preset pressure threshold, the stress shape memory alloy valve opens to release pressure; the internal pressure drops to approximately 15Pa and then closes. During the day, when the ambient temperature rises above -5℃, the temperature shape memory alloy valve closes, and the interior of the energy storage container 1 is kept warm, with a slight positive pressure maintained between 5Pa and 20Pa. When the energy storage container 1 enters the charging / discharging state, the battery management system automatically starts the heating system (liquid cooling unit or air conditioning), and the internal temperature rises, keeping the air intake valve assembly 2 closed, which does not substantially conflict with the voltage stabilization function of this device. The typical application scenario for this device is the standby or transportation state of the energy storage container. In this state, there is no need for charging and discharging, and the main power supply of the environmental control system may be interrupted. The passive voltage regulation capability of this device fills the gap in this working condition.

[0096] Furthermore, during the transportation of energy storage containers, the temperature of the external environment fluctuates significantly depending on the region and day and night. This device can automatically adapt without any human intervention: when passing through cold regions, the air intake valve assembly 2 automatically opens to replenish air, and when passing through warm regions, the air intake valve assembly 2 automatically closes. The exhaust valve assembly 3 always adaptively opens and closes to release pressure according to the internal pressure. No power supply or supervision is required throughout the entire process, making it particularly suitable for energy storage container products that are transported across regions over long distances and placed outdoors for extended periods.

[0097] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0098] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A micro-positive pressure maintaining device for an energy storage container, characterized in that, include: An air intake valve assembly (2) is provided at the air intake channel of the energy storage container (1), including a temperature response drive element. The temperature response drive element responds to changes in the external ambient temperature by generating displacement, deformation or state change to open or close the air intake channel so that external gas can enter the energy storage container (1). An exhaust valve assembly (3) is provided at the exhaust channel of the energy storage container (1), including a pressure response drive element. The pressure response drive element responds to the pressure change inside the energy storage container (1) to generate displacement, deformation or state change, so as to open or close the exhaust channel and allow the internal gas to be discharged. The temperature response drive element and the pressure response drive element are both passive drive elements to maintain a slightly positive pressure state inside the energy storage container (1).

2. The micro-positive pressure maintaining device for energy storage containers according to claim 1, characterized in that: The temperature-responsive drive element includes a temperature shape memory alloy valve plate, which deforms in response to changes in the external ambient temperature to open or close the air intake passage.

3. The micro-positive pressure maintaining device for energy storage containers according to claim 2, characterized in that: The temperature shape memory alloy valve plate is made of a low-temperature shrinkage shape memory alloy; When the external ambient temperature is lower than the first preset temperature, the temperature shape memory alloy valve plate deforms and opens the air intake channel; When the external ambient temperature is higher than the second preset temperature, the temperature shape memory alloy valve plate restores its shape and closes the air intake channel; The second preset temperature is greater than the first preset temperature.

4. The micro-positive pressure maintaining device for energy storage containers according to claim 1, characterized in that: The pressure response drive element includes a stress shape memory alloy valve plate, which generates a stress-induced phase change in response to pressure changes inside the energy storage container (1), and deforms through the phase change to open or close the exhaust passage.

5. The micro-positive pressure maintaining device for energy storage containers according to claim 4, characterized in that: The stress-responsive shape memory alloy valve plate is made of a stress-responsive shape memory alloy. When the internal pressure of the energy storage container (1) reaches the first preset pressure threshold, the stress shape memory alloy valve plate deforms and opens the exhaust channel; When the internal pressure of the energy storage container (1) drops below the second preset pressure threshold, the stress shape memory alloy valve plate resets and closes the exhaust channel; Wherein, the first preset pressure threshold is greater than the second preset pressure threshold.

6. The micro-positive pressure maintaining device for energy storage containers according to claim 4, characterized in that: The stress shape memory alloy valve plate includes a pressure sensing part (31), a stress concentration part (32), and a shape memory deformation part (33). The pressure sensing unit (31) is used to withstand the gas pressure inside the energy storage container (1); The stress concentration part (32) is connected between the pressure sensing part (31) and the shape memory deformation part (33) to convert the pressure action into local concentrated stress acting on the shape memory deformation part (33); When the local concentrated stress reaches the phase transition triggering condition of the shape memory deformation part (33), the shape memory deformation part (33) deforms.

7. The micro-positive pressure maintaining device for energy storage containers according to claim 6, characterized in that: The stress concentration part (32) is a cross-sectional reduction structure. The stress-bearing cross-sectional area of ​​the cross-sectional reduction structure is smaller than the stress-bearing area of ​​the pressure sensing part (31) to amplify the stress acting on the shape memory deformation part (33).

8. The micro-positive pressure maintaining device for energy storage containers according to claim 6, characterized in that: The shape memory deformation part (33) is disposed in the exhaust channel and is configured to change the opening state of the exhaust channel by radial contraction, axial movement or bending deformation when stress-induced phase transformation occurs.

9. The micro-positive pressure maintaining device for energy storage containers according to claim 6, characterized in that: The exhaust valve assembly (3) further includes a seal (14), which is fitted inside the exhaust passage of the exhaust valve assembly (3) and has a through hole; The shape memory deformation part (33) is configured to seal the through hole of the seal (14) when no phase change occurs, so as to close the exhaust channel.

10. The micro-positive pressure maintaining device for energy storage containers according to claim 1, characterized in that: The temperature-responsive drive element is made of at least one of shape memory alloy, bimetallic sheet, or material that deforms with temperature changes; The pressure-responsive drive element is made of shape memory material or pressure-responsive elastic material that can generate mechanical state transitions in response to changes in internal pressure.

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