Design method of explosion relief valve, controller, design system, and storage medium

Abstract

The application discloses a design method, a controller, a design system and a storage medium of an explosion-proof valve, belongs to the technical field of explosion-proof valves, and relates to the technical field of explosion-proof valves. The design method of the explosion-proof valve comprises the following steps: obtaining a maximum pressure value that a box of a battery pack can withstand and first parameter information of a target explosion-proof valve; constructing a relationship model of maximum gas leakage rates corresponding to different pressure relief areas based on the maximum pressure value and the first parameter information; obtaining a peak gas generation rate of a target battery cell; determining a target pressure relief area as the smallest pressure relief area in the relationship model when the maximum gas leakage rate is greater than or equal to the peak gas generation rate; obtaining second parameter information of the target explosion-proof valve; and determining the number of the target explosion-proof valve according to the target pressure relief area and the second parameter information. In this way, the risk of box rupture caused by the mismatch between the explosion-proof valve and the box is eliminated, and the increase in cost caused by the blind selection of too many or too large explosion-proof valves is avoided.

Description

Technical Field

[0001] This application relates to the field of explosion-proof valve technology, and in particular to a design method, controller, design system and storage medium for an explosion-proof valve. Background Technology

[0002] Currently, energy storage battery pack enclosures are typically equipped with explosion-proof valves to release the large amounts of gas generated during thermal runaway. However, most explosion-proof valve designs rely on gas generation data from the battery cells or simple pressure thresholds, without considering the actual maximum mechanical pressure resistance of the battery pack enclosure. This leads to two problems: firstly, insufficient pressure relief capacity of the explosion-proof valves, causing the enclosure to rupture during thermal runaway and resulting in catastrophic accidents; and secondly, the use of excessively large pressure relief valves, increasing design costs. Summary of the Invention

[0003] This application provides a design method, controller, design system, and storage medium for an explosion-proof valve, addressing the following issues in related technologies: on the one hand, the explosion-proof valve design may result in insufficient pressure relief capacity, causing the enclosure to rupture during battery pack thermal runaway and leading to catastrophic accidents; on the other hand, it may lead to the use of excessively large pressure relief valves, increasing design costs.

[0004] To achieve the above objectives, according to a first aspect of this application, a design method for an explosion-proof valve is provided, comprising: Obtain the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve; A relationship model for the maximum venting rate corresponding to different venting areas is constructed based on the maximum pressure value and the first parameter information. Obtain the peak gas production rate of the target cell, and determine the minimum pressure relief area in the relational model when the maximum gas leakage rate is greater than or equal to the peak gas production rate as the target pressure relief area. Obtain the second parameter information of the target explosion-proof valve, and determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information.

[0005] Optionally, before obtaining the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve, the following steps are included: Gas is introduced into the chamber through at least one interface and the other interfaces of the chamber are sealed, so that the internal gas pressure of the chamber increases to the peak pressure value. The maximum pressure that the chamber can withstand is determined based on the peak pressure value.

[0006] Optionally, determining the maximum pressure the chamber can withstand based on the peak pressure value includes: Based on formula Determine the maximum pressure value that the chamber can withstand, where P1 is the peak pressure value, P maxThe maximum pressure value is given by k, which is the engineering design safety factor, and k > 1.

[0007] Optionally, .

[0008] Optionally, the first parameter information of the target explosion-proof valve includes the flow coefficient of the target explosion-proof valve, and the relationship model for the maximum venting rate corresponding to different pressure relief areas is constructed based on the maximum pressure value and the first parameter information, including: Based on formula A model is constructed to show the relationship between the maximum venting rate for different venting areas. For the maximum venting rate, C d Let A be the flow coefficient of the target explosion-proof valve, A be the pressure relief area, and P be the flow coefficient of the target explosion-proof valve. max The maximum pressure value is K, and the critical flow factor is determined by the specific heat ratio and temperature of the hot gas inside the box.

[0009] Optionally, obtaining the second parameter information of the target explosion-proof valve, and determining the number of target explosion-proof valves based on the target pressure relief area and the second parameter information includes: Obtain the pressure relief area of ​​the target explosion-proof valve and calculate the ratio of the target pressure relief area to the pressure relief area of ​​the target explosion-proof valve; The ratio of the target pressure relief area to the target explosion-proof valve pressure relief area is rounded up to obtain the number of target explosion-proof valves.

[0010] Optionally, the peak gas production rate of the target cell is obtained, and the minimum pressure relief area in the relational model corresponding to the maximum gas leakage rate being greater than or equal to the peak gas production rate is determined as the target pressure relief area, including: The peak gas generation rate of the target battery cell was obtained by adiabatic thermal runaway calorimetry testing. By comparing the peak gas production rate with the relational model, the minimum pressure relief area in the relational model corresponding to the maximum gas release rate being greater than or equal to the peak gas production rate is determined as the target pressure relief area.

[0011] According to a second aspect of this application, a controller is provided, comprising: The acquisition module is used to acquire the maximum pressure value that the battery pack housing can withstand, the first parameter information of the target explosion-proof valve, the peak gas production rate of the target cell, and the second parameter information of the target explosion-proof valve. The execution module is used to construct a relationship model of the maximum venting rate corresponding to different venting areas based on the maximum pressure value and the first parameter information. The determination module is used to determine the minimum pressure relief area in the relational model when the maximum gas relief rate is greater than or equal to the peak gas production rate as the target pressure relief area. The determination module is also used to determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information.

[0012] According to a third aspect of this application, a design system for an explosion-proof valve is also provided, comprising: A pressurization device is used to perform destructive pressure limit tests on the battery pack casing to determine the maximum pressure value that the casing can withstand. As described above, the controller is electrically connected to the pressurization device.

[0013] Optionally, the pressurization device includes: The gas supply assembly, electrically connected to the controller, is used to fill the battery pack housing with gas. The pressure sensor, electrically connected to the controller, is used to detect the pressure value of the air pressure inside the battery pack box acting on the inner wall of the box.

[0014] According to a fourth aspect of this application, a computer-readable storage medium is also provided, on which a computer program is stored, which, when run on a processor, causes the computer to execute the explosion-proof valve design method described above.

[0015] In the explosion-proof valve design method of this application embodiment, the maximum pressure value that the enclosure can withstand is incorporated into the design method, transforming the explosion-proof valve from an "isolated component" into a "safety key" that is strictly matched with the pressure-bearing capacity of the battery pack, thus eliminating the risk of enclosure rupture caused by mismatch between the explosion-proof valve and the enclosure. Furthermore, this design method transforms the selection of explosion-proof valves from qualitative experience-based judgment to quantitative calculation, with verifiable and reproducible results, significantly improving the reliability of the selection. Additionally, by accurately determining the required number of explosion-proof valves without exceeding the maximum pressure value that the enclosure can withstand, the increased cost caused by blindly selecting excessively large or too many explosion-proof valves is avoided.

[0016] Other features and advantages of this application will be described in detail in the following detailed description section. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] To gain a more complete understanding of this application and its beneficial effects, the following description will be provided in conjunction with the accompanying drawings, wherein the same reference numerals in the following description denote the same parts.

[0019] Figure 1 This is a schematic diagram of the controller provided in an embodiment of this application; Figure 2This is a schematic diagram of the controller structure of the hardware operating environment involved in the embodiments of the present invention.

[0020] Figure 3 This is a flowchart illustrating the design method of the explosion-proof valve provided in an exemplary embodiment of this disclosure; Figure 4 This is a flowchart illustrating the process prior to step S300 in the explosion-proof valve design method provided in an exemplary embodiment of this disclosure. Figure 5 This is a schematic diagram of the specific process of step S600 in the explosion-proof valve design method provided in the exemplary embodiment of this disclosure; Figure 6 This is a schematic diagram of the specific process of step S500 in the explosion-proof valve design method provided in the exemplary embodiment of this disclosure.

[0021] Explanation of reference numerals in the attached figures: 10. Controller; 101. Acquisition module; 102. Execution module; 103. Determination module; 104. Processor; 105. Communication bus; 106. User interface; 107. Network interface; 108. Memory. Detailed Implementation

[0022] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this application without creative effort are within the protection scope of this application.

[0023] Currently, energy storage battery pack enclosures are typically equipped with explosion-proof valves to release the large amounts of gas generated during thermal runaway. However, most explosion-proof valve designs rely on gas generation data from the battery cells or simple pressure thresholds, without considering the actual maximum mechanical pressure resistance of the battery pack enclosure. This leads to two problems: firstly, insufficient pressure relief capacity of the explosion-proof valves, causing the enclosure to rupture during thermal runaway and resulting in catastrophic accidents; secondly, the use of excessively large pressure relief valves, increasing design costs and sacrificing the enclosure's sealing and protection levels.

[0024] In view of the above, this application provides a design system for an explosion-proof valve, which includes a pressurizing device and a controller 10. The pressurizing device is used to perform a destructive pressure limit test on the battery pack housing to determine the maximum pressure value that the housing can withstand. The controller 10 is electrically connected to the pressurizing device. Thus, by electrically connecting the pressurizing device and the controller 10, the explosion-proof valve design system establishes a data closed loop. The pressurizing device performs a destructive test on the housing to determine the maximum pressure value that the housing can withstand, and the peak pressure value that the housing can withstand is transmitted to the controller 10 in real time and automatically. By incorporating the maximum pressure value that the housing can withstand into the design method of the explosion-proof valve, the explosion-proof valve is transformed from an "isolated component" into a "safety key" that is strictly matched with the pressure-bearing capacity of the battery pack, eliminating the risk of housing rupture due to mismatch between the explosion-proof valve and the housing. Furthermore, the controller 10 can precisely design the required number of explosion-proof valves while ensuring that the maximum pressure value that the housing can withstand is not exceeded, avoiding increased costs and the problem of sacrificing the sealing and protection level of the housing caused by blindly selecting excessively large or too many explosion-proof valves.

[0025] In some embodiments, the pressurization device includes a gas supply component and a pressure sensor. The gas supply component is electrically connected to the controller 10 and is used to pressurize the battery pack housing with gas. The pressure sensor is also electrically connected to the controller 10 and is used to detect the pressure value exerted by the gas pressure inside the battery pack housing on the inner wall of the housing. Thus, the controller 10 can precisely control the start / stop and pressurization rate of the gas supply component according to a preset program and receive feedback signals from the pressure sensor in real time. This closed-loop control method ensures that the testing process strictly follows the preset scheme and accurately captures the peak pressure value at the moment of housing rupture. This not only improves the accuracy and safety of the test but also provides high-quality, highly reliable input data for subsequent design calculations.

[0026] Please see Figure 1 , Figure 1This is a schematic diagram of the controller 10 provided in an embodiment of this application. The controller 10 includes an acquisition module 101, an execution module 102, and a determination module 103. The acquisition module 101 is used to acquire the maximum pressure value that the battery pack casing can withstand, the first parameter information of the target explosion-proof valve, the peak gas generation rate of the target battery cell, and the second parameter information of the target explosion-proof valve. The execution module 102 is used to construct a relationship model of the maximum gas release rate corresponding to different pressure release areas based on the maximum pressure value and the first parameter information. The determination module 103 is used to determine the smallest pressure release area in the relationship model corresponding to the maximum gas release rate being greater than or equal to the peak gas generation rate as the target pressure release area. The determination module 103 is also used to determine the number of target explosion-proof valves based on the target pressure release area and the second parameter information. In this way, the controller 10 can automatically and efficiently complete a series of operations such as data acquisition, model construction, condition judgment, and result calculation, which greatly improves the efficiency and accuracy of explosion-proof valve design and avoids errors that may occur from manual calculation.

[0027] In some embodiments, refer to Figure 2 , Figure 2 This is a schematic diagram of the controller 10 of the hardware operating environment involved in an embodiment of the present invention. The controller 10 may include: a processor 104, such as a CPU; a communication bus 105; a user interface 106; a network interface 107; and a memory 108. The communication bus 105 is used to implement communication between these components. The user interface 106 may include a display screen or an input unit such as a keyboard; optionally, the user interface 106 may also include a standard wired interface or a wireless interface. The network interface 107 may optionally include a standard wired interface or a wireless interface (such as a Wi-Fi interface). The memory 108 may be a high-speed RAM or a stable, non-volatile memory, such as a disk storage device. Optionally, the memory 108 may also be a storage device independent of the aforementioned processor 104.

[0028] Those skilled in the art will understand that Figure 2 The structure shown does not constitute a limitation on the controller 10 and may include more or fewer components than shown, or combine certain components, or have different component arrangements.

[0029] like Figure 2 As shown, the memory 108, which serves as a computer storage medium, may include an operating system, a network communication module, a user interface module, and a design method for an explosion-proof valve.

[0030] Figure 2 The controller 10 shown calls the design method of the explosion-proof valve stored in the memory 108 through the processor 104 and performs the following operations: Obtain the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve; A relationship model for the maximum venting rate corresponding to different venting areas is constructed based on the maximum pressure value and the first parameter information. Obtain the peak gas production rate of the target cell, and determine the minimum pressure relief area in the relational model when the maximum gas leakage rate is greater than or equal to the peak gas production rate as the target pressure relief area. Obtain the second parameter information of the target explosion-proof valve, and determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information.

[0031] Furthermore, the processor 104 can invoke the design method of the explosion-proof valve stored in the memory 108, and also perform the following operations: Before obtaining the maximum pressure that the battery pack enclosure can withstand and the first parameter information of the target explosion-proof valve, the following should be included: Gas is introduced into the chamber through at least one interface and the other interfaces of the chamber are sealed, so that the internal gas pressure of the chamber increases to the peak pressure value. The maximum pressure that the chamber can withstand is determined based on the peak pressure value.

[0032] Furthermore, the processor 104 can invoke the design method of the explosion-proof valve stored in the memory 108, and also perform the following operations: The maximum pressure that the chamber can withstand is determined based on the peak pressure value, including: Based on formula Determine the maximum pressure value that the chamber can withstand, where P1 is the peak pressure value, P max The maximum pressure value is given by k, which is the engineering design safety factor, and k > 1.

[0033] Furthermore, the processor 104 can invoke the design method of the explosion-proof valve stored in the memory 108, and also perform the following operations: The first parameter information of the target explosion-proof valve includes the flow coefficient of the target explosion-proof valve. A relationship model for the maximum venting rate corresponding to different pressure relief areas is constructed based on the maximum pressure value and the first parameter information, including: Based on formula A model is constructed to show the relationship between the maximum venting rate for different venting areas. For the maximum venting rate, C d Let A be the flow coefficient of the target explosion-proof valve, A be the pressure relief area, and P be the flow coefficient of the target explosion-proof valve. max The maximum pressure value is K, and the critical flow factor is determined by the specific heat ratio and temperature of the hot gas inside the box.

[0034] Furthermore, the processor 104 can invoke the design method of the explosion-proof valve stored in the memory 108, and also perform the following operations: Obtain the second parameter information of the target explosion-proof valve, and determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information, including: Obtain the pressure relief area of ​​the target explosion-proof valve and calculate the ratio of the target pressure relief area to the pressure relief area of ​​the target explosion-proof valve; The ratio of the target pressure relief area to the target explosion-proof valve pressure relief area is rounded up to obtain the number of target explosion-proof valves.

[0035] Furthermore, the processor 104 can invoke the design method of the explosion-proof valve stored in the memory 108, and also perform the following operations: Obtain the peak gas production rate of the target cell, and determine the minimum pressure relief area in the relational model corresponding to the maximum gas leakage rate being greater than or equal to the peak gas production rate as the target pressure relief area, including: The peak gas generation rate of the target battery cell was obtained by adiabatic thermal runaway calorimetry testing. By comparing the peak gas production rate with the relational model, the minimum pressure relief area in the relational model corresponding to the maximum gas release rate being greater than or equal to the peak gas production rate is determined as the target pressure relief area.

[0036] Through the above description of the embodiments, those skilled in the art can clearly understand that the methods of the following embodiments can be implemented by means of software plus necessary general-purpose hardware platforms. Of course, they can also be implemented by hardware, but in many cases the former is a better implementation method. Based on this understanding, the technical solution of the present invention, or the part that contributes to the prior art, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk) as described above, and includes several instructions to cause a terminal device (which may be a mobile phone, computer, server, or network device, etc.) to execute the methods of the various embodiments of the present invention.

[0037] Based on the above-described explosion-proof valve design system, this invention also proposes a design method for explosion-proof valves. Please refer to [link / reference]. Figure 3 , Figure 3 This is a flowchart illustrating the design method of the explosion-proof valve provided in an exemplary embodiment of this disclosure.

[0038] The design method for explosion-proof valves includes the following steps: Step S300: Obtain the maximum pressure value that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve.

[0039] It should be noted that the maximum pressure that the battery pack casing can withstand is a safety boundary that the casing cannot incur. The first parameter information of the target explosion-proof valve can be selected as needed. For example, in one embodiment, the first parameter information of the target explosion-proof valve may include the flow coefficient of the target explosion-proof valve. This flow coefficient represents the difference between the actual flow efficiency of the target explosion-proof valve and the ideal orifice (due to friction, eddies, etc.), and the flow coefficient is typically 0.6-0.9. Furthermore, the selection of the target explosion-proof valve needs to be combined with requirements such as opening pressure and response time. The opening pressure of the target explosion-proof valve is much lower than the maximum pressure value. After selecting the target explosion-proof valve, its flow coefficient can be determined. In other embodiments, the first parameter information of the target explosion-proof valve may also include the maximum flow rate of the target explosion-proof valve under standard conditions, the density of the medium passing through the target explosion-proof valve under standard conditions, the absolute temperature at the valve inlet of the target explosion-proof valve, the absolute pressure at the valve inlet of the target explosion-proof valve, and the allowable pressure difference across the target explosion-proof valve. The flow coefficient of the target explosion-proof valve can be determined based on the maximum flow rate of the target explosion-proof valve under standard conditions, the density of the medium passing through the target explosion-proof valve under standard conditions, the absolute temperature at the valve inlet of the target explosion-proof valve, the absolute pressure at the valve inlet of the target explosion-proof valve, and the allowable pressure difference across the valve.

[0040] Step S400: Construct a relationship model of the maximum venting rate corresponding to different venting areas based on the maximum pressure value and the first parameter information.

[0041] It should be noted that the maximum venting rate represents the maximum rate at which gas inside the chamber needs to be vented out when the chamber can withstand the maximum pressure.

[0042] Step S500: Obtain the peak gas production rate of the target cell, and determine the minimum pressure relief area in the relational model when the maximum gas leakage rate is greater than or equal to the peak gas production rate as the target pressure relief area.

[0043] In this step, the battery cell generates extremely high levels of gas during thermal runaway, and its peak gas generation rate represents the minimum requirement for the enclosure's "venting capacity." To ensure that the pressure inside the enclosure does not continuously accumulate and exceed the maximum pressure the enclosure can withstand, the maximum venting rate must be at least equal to this peak gas generation rate. The peak gas generation rate is compared with the previously established relationship model to identify all venting areas that satisfy the "supply greater than or equal to demand" condition, and the smallest venting area is selected as the target venting area. Choosing the smallest venting area as the target venting area ensures that the design meets the rigid requirements for safe venting while avoiding the increased cost caused by selecting an excessively large venting area.

[0044] Step S600: Obtain the second parameter information of the target explosion-proof valve, and determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information.

[0045] The second parameter information of the target explosion-proof valve can be selected as needed. For example, in one embodiment, the second parameter information of the target explosion-proof valve may include the pressure relief area of ​​the target explosion-proof valve. In another embodiment, when the valve orifice of the target explosion-proof valve is circular, the second parameter information may also include the diameter of the valve orifice of the target explosion-proof valve.

[0046] In the explosion-proof valve design method of this application embodiment, the maximum pressure value that the enclosure can withstand is incorporated into the design method, transforming the explosion-proof valve from an "isolated component" into a "safety key" that is strictly matched with the pressure-bearing capacity of the battery pack, thus eliminating the risk of enclosure rupture due to mismatch between the explosion-proof valve and the enclosure. Furthermore, this design method transforms the selection of explosion-proof valves from qualitative experience-based judgment to quantitative calculation, making the results verifiable and reproducible, significantly improving the reliability of the selection. In addition, by accurately determining the required number of explosion-proof valves without exceeding the maximum pressure value that the enclosure can withstand, the increased costs and compromised enclosure sealing and protection levels caused by blindly selecting excessively large or too many explosion-proof valves are avoided.

[0047] Specifically, refer to Figure 4 , Figure 4 This is a flowchart illustrating the process prior to step S300 in the explosion-proof valve design method provided in an exemplary embodiment of this disclosure. Before obtaining the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve, the process includes: Step S100: Inject gas into the chamber through at least one interface and seal the other interfaces of the chamber to increase the internal pressure of the chamber to the peak pressure value.

[0048] It should be noted that the gas introduced into the chamber can be an inert gas. Inert gases typically refer to chemically inert gases that do not readily react with other substances, primarily used to isolate oxygen or dilute flammable gases. Examples include nitrogen, helium, or neon. Specifically, this application does not limit the specific type. Furthermore, the inert gas is introduced into the chamber at a constant low rate through at least one interface, thereby simulating the pressurization process inside the chamber.

[0049] Inert gas is continuously pumped into the enclosure until permanent defects appear in the enclosure structure, such as weld cracking or seal failure. The key criterion for determining permanent defects in the enclosure structure is: the pressure readings detected by the pressure sensor reach a peak value and then fail to rise further, or the pressure readings begin to steadily decrease after reaching the peak value. The pressure sensor readings are recorded in real time during the continuous pumping of inert gas into the enclosure; the peak pressure value is the highest among the recorded values. The peak pressure value is the ultimate failure pressure of the enclosure.

[0050] Step S200: Determine the maximum pressure value that the chamber can withstand based on the peak pressure value.

[0051] This step simulates the pressure accumulation process within the enclosure under extreme conditions. By continuously pressurizing until the enclosure fails or reaches a critical state, the actual peak pressure value is obtained. Subsequently, the maximum pressure the enclosure can withstand is determined based on the peak pressure value. This experimental method allows for the determination of the actual pressure limit of the enclosure under real manufacturing processes and material properties, avoiding potential deviations from theoretical calculations or simulations. It provides the most realistic and reliable "safety upper limit" for the design of explosion-proof valves.

[0052] In one embodiment, step S200, determining the maximum pressure the housing can withstand based on the peak pressure value, includes: Step S210, based on formula Determine the maximum pressure value that the chamber can withstand, where P1 is the peak pressure value, P max The maximum pressure value is given by k, which is the engineering design safety factor, and k > 1.

[0053] In this step, an engineering design safety factor k is introduced, k>1, based on the formula. The maximum pressure that the enclosure can withstand is determined. By introducing a safety factor k greater than 1, the measured peak pressure is reduced to a more conservative maximum pressure value. This means that in the design, the peak pressure inside the enclosure after the explosion-proof valve opens will be strictly controlled below the maximum pressure value, leaving sufficient safety margin for the enclosure itself to cope with the uncertainties brought about by complex operating conditions such as material aging, batch differences, and dynamic impacts. This achieves a scientific transformation from "destructive limit" to "safe design value," greatly improving the safety and reliability of the battery pack throughout its life cycle.

[0054] Furthermore, If the value of k is less than 1.2, the safety margin is too small, and the enclosure may face the risk of failure due to minor fluctuations in actual application. If the value of k is greater than 2, the design target is too conservative, which will lead to an excessively large pressure relief area of ​​the selected explosion-proof valve, resulting in increased costs and wasted space. Therefore, the range of 1.2 to 2 can effectively absorb the risks brought about by engineering uncertainties, ensuring safety, without over-designing, thus achieving an optimal balance between safety and cost.

[0055] When the pressure inside the enclosure reaches the maximum pressure the enclosure can withstand, the explosion-proof valve must be able to provide sufficient discharge flow. According to the principle of choked flow (also known as sonic flow), when gas is released from a high-pressure area through the orifice (explosion-proof valve) to a low-pressure area (atmosphere), the flow velocity increases with the pressure difference. There exists a critical pressure ratio. For diatomic gases such as air, this ratio is approximately... In other words, when the absolute pressure inside the enclosure exceeds the external atmospheric pressure by approximately 1.9 times, the gas flow velocity at the outlet of the explosion-proof valve will reach the local speed of sound. Once the speed of sound is reached, the mass flow rate through the explosion-proof valve will no longer change, reaching its maximum value. At this point, the flow rate mainly depends on the venting area, i.e., the area of ​​the explosion-proof valve. The first parameter information of the target explosion-proof valve includes the flow coefficient of the target explosion-proof valve. Step S400, based on the maximum pressure value and the first parameter information, constructs a relationship model for the maximum venting rate corresponding to different venting areas, including: Step S410, based on formula A model was constructed to show the relationship between the maximum venting rate and different venting areas. For the maximum venting rate, C d Let A be the flow coefficient of the target explosion-proof valve, A be the pressure relief area, and P be the flow coefficient of the target explosion-proof valve. max The maximum pressure value is K, and the critical flow factor is determined by the specific heat ratio and temperature of the hot gas inside the box.

[0056] In this step, The maximum venting rate can be understood as the maximum venting rate that the explosion-proof valve needs to achieve, and A can also be understood as the pressure relief area that the explosion-proof valve needs to achieve. C d This represents the difference between the actual flow efficiency of the explosion-proof valve and the ideal orifice (due to friction, eddies, etc.). C d The value is typically 0.6-0.9. It depends on the target explosion-proof valve model. Additionally, the formula... Based on the maximum pressure value P max As the driving pressure difference, combined with the flow characteristics C of the explosion-proof valve itself d This paper scientifically describes the quantitative relationship between the pressure relief area A and the maximum achievable gas relief rate. Through this model, it can be determined how quickly an explosion-proof valve with each pressure relief area can discharge gas when the upper limit of the safe pressure is reached. This provides a direct calculation basis for the gas generation rate of the subsequent matching battery cells, enabling the selection of explosion-proof valves to move from qualitative to quantitative methods.

[0057] formula It is based on the principle of congested flow, in which, , R represents the specific heat capacity ratio of the hot gas inside the chamber. For typical thermal runaway gases (containing at least one of H2, CO, CO, and hydrocarbons), the γ value of the gas mixture is usually between 1.2 and 1.4. For simplicity or conservatism, the value of air (γ = 1.4) can be used. u is a universal gas constant, a physical constant, with a value of 8.314 J / (mol·K). T is the thermodynamic temperature of the hot gas inside the chamber, which can be estimated by measuring the temperature of the ejected gas in a thermal runaway experiment. M is the molar mass of the hot gas inside the chamber.

[0058] It should be noted that, due to P max The above steps provide the information, and experimental analysis can determine γ, M, and T. Additionally, Cd can be determined based on the target explosion-proof valve, and R... u Given that the universal gas constant is known, P max γ, M, T, C d and R u Substitute into the formula. At this point, the only variable in the formula is the pressure relief area A. Plot the pressure relief area A as the x-axis and the calculated maximum pressure relief rate... The vertical axis is used because Therefore, the relational model is a straight line passing through the origin. This line represents the discharge capacity that the battery pack casing can provide under safe pressure boundaries. Each point on the line (A, ...) represents the discharge capacity of the battery pack. Surface: If an explosion-proof valve of this model with an area of ​​A is installed, when the pressure inside the chamber reaches the maximum pressure value, it can... The rate at which gas is released.

[0059] Reference Figure 5 , Figure 5 This is a schematic flowchart illustrating step S600 in the explosion-proof valve design method provided in an exemplary embodiment of this disclosure. Step S600 involves obtaining the second parameter information of the target explosion-proof valve and determining the number of target explosion-proof valves based on the target pressure relief area and the second parameter information, including: Step S610: Obtain the pressure relief area of ​​the target explosion-proof valve and calculate the ratio of the target pressure relief area to the pressure relief area of ​​the target explosion-proof valve; Step S620: Round up the ratio of the target pressure relief area to the target explosion-proof valve's pressure relief area using the rounding method to obtain the number of target explosion-proof valves.

[0060] In the above steps, since the actual number of explosion-proof valves installed must be an integer, the ratio of the calculated target pressure relief area to the pressure relief area of ​​a single explosion-proof valve is likely not an integer. Using the "rounding up" method means that even if the required total area is slightly larger than an integer multiple of the area of ​​a single valve, an additional explosion-proof valve will be added. This approach ensures that the actual total pressure relief area is always greater than or equal to the theoretically calculated target pressure relief area, thus guaranteeing that the actual pressure relief capacity is not lower than the design requirements, providing a final and reliable engineering guarantee for safe pressure relief.

[0061] Reference Figure 6 , Figure 6 This is a schematic flowchart of step S500 in the explosion-proof valve design method provided in an exemplary embodiment of this disclosure. Step S500 involves obtaining the peak gas generation rate of the target battery cell and determining the minimum pressure relief area in the relational model corresponding to the maximum gas leakage rate being greater than or equal to the peak gas generation rate as the target pressure relief area. This includes: Step S510: Obtain the peak gas generation rate of the target cell through adiabatic thermal runaway calorimetry test.

[0062] It should be noted that adiabatic thermal runaway calorimetry is an experimental method for accurately measuring the thermal behavior and gas production of a battery during thermal runaway in an adiabatic environment (i.e., without heat exchange with the outside world). The peak gas production rate of the target cell is the maximum instantaneous value of the amount of gas produced per unit time during the adiabatic thermal runaway test.

[0063] Step S520: Compare the peak gas production rate with the relational model, and determine the minimum pressure relief area in the relational model when the maximum gas relief rate is greater than or equal to the peak gas production rate as the target pressure relief area.

[0064] In this step, the adiabatic thermal runaway calorimetry (ARC) test simulates the thermal runaway process of the battery cell under the most severe adiabatic environment and accurately measures its gas production rate. The peak gas production rate obtained from this test best represents the maximum venting requirement of the battery cell under extreme conditions. By setting a hard constraint that the maximum venting rate is greater than or equal to the peak gas production rate, all design schemes with insufficient pressure relief capacity are mathematically eliminated. This ensures that under any circumstances, the venting rate of the explosion-proof valve will not be lower than the gas production rate of the battery cell, thereby firmly locking the pressure inside the enclosure within the maximum pressure value and achieving absolute safety redundancy. By specifying and selecting the minimum pressure relief area, the cost waste caused by blindly increasing the explosion-proof valve specifications and the structural strength weakening caused by needing to open a large hole to install the explosion-proof valve are avoided, achieving cost savings while meeting safety requirements.

[0065] In the description of this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first" or "second" may explicitly or implicitly include one or more features. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0066] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0067] The embodiments, implementation methods, and related technical features of this application can be combined and substituted for each other without conflict.

[0068] The above are merely preferred embodiments of this application and are not intended to limit this application in any way. Any simple modifications, equivalent changes, and alterations made to the above embodiments based on the technical essence of this application without departing from the scope of the technical solution of this application shall still fall within the scope of the technical solution of this application.

Claims

1. A design method for an explosion-proof valve, characterized in that, include: Obtain the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve; Based on the maximum pressure value and the first parameter information, a relationship model is constructed for the maximum venting rate corresponding to different venting areas. Obtain the peak gas production rate of the target cell, and determine the minimum pressure relief area in the relational model when the maximum gas leakage rate is greater than or equal to the peak gas production rate as the target pressure relief area; Obtain the second parameter information of the target explosion-proof valve, and determine the number of the target explosion-proof valves based on the target pressure relief area and the second parameter information.

2. The design method of the explosion-proof valve according to claim 1, characterized in that, Before obtaining the maximum pressure that the battery pack housing can withstand and the first parameter information of the target explosion-proof valve, the following steps are included: Gas is introduced into the chamber through at least one interface and the other interfaces of the chamber are sealed, so that the internal pressure of the chamber increases to the peak pressure value. The maximum pressure that the chamber can withstand is determined based on the peak pressure value.

3. The design method of the explosion-proof valve according to claim 2, characterized in that, Determining the maximum pressure that the chamber can withstand based on the peak pressure value includes: Based on formula Determine the maximum pressure value that the chamber can withstand, where P1 is the peak pressure value, P max The maximum pressure value is given, and k is the engineering design safety factor, where k>1.

4. The design method of the explosion-proof valve according to claim 3, characterized in that, 1.2≤k≤2。 5. The design method of the explosion-proof valve according to claim 1, characterized in that, The first parameter information of the target explosion-proof valve includes the flow coefficient of the target explosion-proof valve, and the relationship model for constructing the maximum venting rate corresponding to different pressure relief areas based on the maximum pressure value and the first parameter information includes: Based on formula A model is constructed to show the relationship between the maximum venting rate for different venting areas. C is the maximum venting rate. d Let A be the flow coefficient of the target explosion-proof valve, A be the pressure relief area, and P be the flow coefficient of the target explosion-proof valve. max The maximum pressure value is K, and the critical flow factor is determined by the specific heat ratio and temperature of the hot gas inside the chamber.

6. The design method of the explosion-proof valve according to claim 1, characterized in that, The step of obtaining the second parameter information of the target explosion-proof valve and determining the number of the target explosion-proof valves based on the target pressure relief area and the second parameter information includes: Obtain the pressure relief area of ​​the target explosion-proof valve, and calculate the ratio of the target pressure relief area to the pressure relief area of ​​the target explosion-proof valve; The ratio of the target pressure relief area to the target explosion-proof valve pressure relief area is rounded up to obtain the number of target explosion-proof valves.

7. The design method of the explosion-proof valve according to any one of claims 1 to 6, characterized in that, The process of obtaining the peak gas production rate of the target battery cell and determining the minimum pressure relief area in the relational model corresponding to the maximum gas production rate being greater than or equal to the peak gas production rate includes: The peak gas production rate of the target battery cell was obtained by adiabatic thermal runaway calorimetry. The peak gas production rate is compared with the relational model, and the smallest pressure relief area in the relational model corresponding to the maximum gas relief rate being greater than or equal to the peak gas production rate is determined as the target pressure relief area.

8. A controller, characterized in that, include: The acquisition module is used to acquire the maximum pressure value that the battery pack housing can withstand, the first parameter information of the target explosion-proof valve, the peak gas production rate of the target cell, and the second parameter information of the target explosion-proof valve. The execution module is used to construct a relationship model of the maximum venting rate corresponding to different venting areas based on the maximum pressure value and the first parameter information. The determining module is used to determine the minimum pressure relief area in the relational model corresponding to the maximum gas relief rate being greater than or equal to the peak gas production rate as the target pressure relief area. The determining module is also used to determine the number of target explosion-proof valves based on the target pressure relief area and the second parameter information.

9. A design system for an explosion-proof valve, characterized in that, include: A pressurization device is used to perform a destructive pressure limit test on the battery pack housing to determine the maximum pressure value that the housing can withstand. The controller as described in claim 8 is electrically connected to the pressurizing device.

10. The explosion-proof valve design system according to claim 9, characterized in that, The pressurizing device includes: A gas supply assembly, electrically connected to the controller, is used to fill the battery pack housing with gas. A pressure sensor, electrically connected to the controller, is used to detect the pressure value of the air pressure inside the battery pack housing acting on the inner wall of the housing.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run on the processor, it causes the computer to perform the design method of the explosion-proof valve as described in any one of claims 1 to 7.

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