Lithium battery energy storage module with multiple cooperative protection functions and thermal spread prevention method thereof

Abstract

This application discloses a lithium battery energy storage module with multiple collaborative protection functions and its thermal propagation prevention method, including a cell array composed of several individual cells arranged in a matrix; a system harness for high-power power transmission, communication signal interaction, and parameter acquisition of individual cells between the cell array and the high-voltage busbar and energy storage converter; a harness protection component including several fiberglass tubes; all system harnesses inside the energy storage module are run through the fiberglass tubes; a cell thermal insulation component, in which high-purity quartz wool is vertically fixed in the assembly gaps between individual cells; a pressure relief and avoidance wiring structure, including a wiring-free safety area based on the center of the top vent valve of any individual cell, and a system harness fully covered with fiberglass tubes to avoid the vent valve pressure relief channel; and a pressure relief monitoring unit including a miniature pressure sensor and a BMS. This application can block the thermal propagation path, prevent secondary fires of the harness, ensure unobstructed pressure relief, and achieve early warning of thermal runaway.

Description

Technical Field

[0001] This application relates to the field of battery safety protection technology, specifically to a lithium battery energy storage module with multiple synergistic protection functions and a method for preventing thermal spread. Background Technology

[0002] Lithium-ion batteries for energy storage are widely used in large-scale electrochemical energy storage power stations, industrial and commercial energy storage equipment, and residential energy storage scenarios due to their advantages such as moderate energy density, long cycle life, and low operating costs. However, frequent fires and explosions caused by thermal runaway of lithium-ion batteries seriously restrict the safe and large-scale development of the energy storage industry, and thermal propagation control has become a core hard indicator in the design of energy storage products.

[0003] Lithium-ion batteries are highly susceptible to thermal runaway under conditions such as overcharging, internal micro-short circuits, high ambient temperatures, and cell aging. UL9540A, as a globally authoritative testing standard for the spread of thermal runaway fires in battery energy storage systems, has become a core basis for industry safety access. This standard quantifies the risk of thermal spread through a three-tiered progressive testing process involving cells, modules, and units. It requires that, under normal temperature conditions and full SOC, after a single cell's thermal runaway is triggered using standard methods, no chain reaction should occur at the cell, module, unit, or large-scale levels. Adjacent equipment should not experience open flames, explosions, or irreversible damage, and temperature and gas emissions should meet the standard limits.

[0004] Currently, most mainstream lithium battery energy storage module protection solutions on the market are passive protection systems, relying solely on the battery management system (BMS) to collect cell voltage and temperature for post-alarm monitoring, and using the built-in fire extinguishing device in the enclosure to provide remediation after a fire occurs. They lack a front-end structural protection design that coordinates multiple dimensions such as cells, wiring harnesses, heat insulation, pressure relief, and monitoring, making it difficult to pass the stringent testing of the new UL9540A standard, which has become a core technical barrier for energy storage products to go global and for large-scale energy storage power stations to connect to the grid.

[0005] Therefore, the industry urgently needs a proactive, multi-layered, collaborative protection solution that integrates multiple structures and monitoring dimensions to avoid various safety hazards related to the thermal spread of lithium batteries from the source. Summary of the Invention

[0006] To address the aforementioned issues, the purpose of this application is to provide a lithium battery energy storage module with multiple collaborative protection functions and its thermal propagation prevention method. Through the coordinated use of multiple structures and monitoring methods, including cell selection, high-temperature protection of wiring harnesses, physical insulation of cells, pressure relief area avoidance wiring, and pressure monitoring of vent valves, the thermal propagation path can be blocked, secondary fires of wiring harnesses can be avoided, pressure relief can be ensured, and early warning of thermal runaway can be achieved, fully meeting the safety assessment requirements of the UL9540A standard.

[0007] According to one aspect of this application, a lithium battery energy storage module with multiple collaborative protection functions is provided, comprising:

[0008] The battery cell array consists of multiple individual battery cells arranged in a uniform matrix. The system wiring harness is used for high-power power transmission, communication signal interaction, or data acquisition. The wiring harness protection assembly includes multiple fiberglass tubes woven from alkali-free glass fiber with dense, non-porous walls. All system wiring harnesses are run through the fiberglass tubes for complete protection. The pressure relief monitoring unit includes multiple miniature pressure sensors and a BMS communicating with them. The miniature pressure sensors are positioned at the outlet of the vent valve of each individual battery cell. A quartz wool insulation assembly is vertically installed between adjacent individual battery cells, completely covering the height and width of the cell's sidewall. A no-wiring safety zone is defined with the center of the vent valve at the top of any individual battery cell as a reference. Fiberglass tubes carrying the system wiring harness are arranged outside this no-wiring safety zone to avoid the pressure relief channel of the vent valve.

[0009] The BMS is configured to: preset a first pressure rate threshold, a second pressure rate threshold, a first-level thermal runaway risk threshold, and a second-level thermal runaway risk threshold; collect pressure time-series signals from each micro pressure sensor; calculate the first-order rate of change of pressure dp / dt and the second-order rate of change of pressure d²p / dt², where p is pressure, t is time, dp represents the infinitesimal change in pressure, and dt represents the infinitesimal change in time; when dp / dt is lower than the first pressure rate threshold and d²p / dt² is less than a preset acceleration judgment threshold, it is judged as a normal gas production condition; when dp / dt exceeds the second pressure rate threshold and d²p / dt² remains positive for a preset duration judgment time, it is judged as an abnormal gas production condition; when d²p / dt² turns from positive to negative after the pressure accumulates and the pressure value p is higher than a preset high-pressure threshold for a preset high-pressure holding time, it is judged as a pressure relief blockage condition.

[0010] Preferably, in some embodiments of this application, the BMS also calculates the internal gas pressure P of a single battery cell based on the following formula. 内 ;

[0011] P 内 =nRT / V0,

[0012] Where n is the amount of substance of the gas inside a single cell, in mol; R is the molar gas constant; T is the temperature of the single cell; V0 is the free volume inside the single cell; when P 内 Greater than or equal to the preset rated valve opening pressure P 额 At that time, the vent valve on the top of the individual battery cell is opened.

[0013] Preferably, in some embodiments of this application, the BMS is further configured as follows:

[0014] When an abnormal gas production condition is identified, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual cell and the temperature rise rate dT / dt of the temperature T of the individual cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula:

[0015] R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt),

[0016] Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of a single cell, and satisfy w1+w2+w3=1; f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; when R exceeds the first-level thermal runaway risk threshold, a first-level warning is triggered, and when R exceeds the second-level thermal runaway risk threshold, a second-level warning is triggered.

[0017] Preferably, in some embodiments of this application, the BMS is further configured as follows:

[0018] When a Level 2 warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

[0019] Preferably, in some embodiments of this application, the energy storage module further includes a stainless steel housing, which has a pre-reserved overall pressure relief channel for discharging flammable high-temperature gas released by the vent valves of each individual battery cell.

[0020] According to another aspect of this application, this application also provides a method for preventing thermal propagation in lithium battery energy storage modules, applied to the energy storage module of any of the above embodiments, the prevention method including:

[0021] Single cell array arrangement: Multiple single cells are arranged in a matrix to form a cell array;

[0022] System wiring harness protection: The system wiring harness is fully enclosed and protected by being run through a fiberglass tube;

[0023] Individual cell isolation setup: Quartz wool isolation components are vertically installed between two adjacent individual cells, so that the quartz wool isolation components completely cover the height and width directions of the individual cell sidewalls;

[0024] Pressure relief zone avoidance setting: A no-wiring safety zone is defined with the center of the vent valve on the top of any single cell as the reference. Fiberglass tubes with system wiring harnesses are arranged outside the no-wiring safety zone to avoid the pressure relief channel of the vent valve.

[0025] Pressure relief monitoring and early warning: Miniature pressure sensors are installed at the outlet of the vent valve of each individual cell, and all miniature pressure sensors are connected to the BMS for communication.

[0026] BMS presets a first pressure rate threshold, a second pressure rate threshold, a first-level thermal runaway risk threshold, and a second-level thermal runaway risk threshold;

[0027] Collect the time-series air pressure signals from each miniature air pressure sensor; calculate the first-order rate of change of air pressure dp / dt and the second-order rate of change of air pressure d²p / dt², where p is air pressure, t is time, dp represents the infinitesimal change in air pressure, and dt represents the infinitesimal change in time; when dp / dt is lower than the first air pressure rate threshold and d²p / dt² is less than the preset acceleration judgment threshold, it is judged as a normal gas production condition; when dp / dt exceeds the second air pressure rate threshold and d²p / dt² remains positive for a preset duration judgment time, it is judged as an abnormal gas production condition; when the air pressure accumulates and d²p / dt² turns from positive to negative, and the air pressure value p is higher than the preset high pressure threshold for a preset high pressure holding time, it is judged as a pressure relief blockage condition.

[0028] Preferably, in some embodiments of this application, the following steps are further included:

[0029] BMS calculates the internal air pressure P of a single battery cell based on the following formula. 内 ;

[0030] P 内 =nRT / V0,

[0031] Where n is the amount of substance of the gas inside a single cell, in mol; R is the molar gas constant; T is the temperature of the single cell; and V0 is the free volume inside the single cell.

[0032] When P 内 Greater than or equal to the preset rated valve opening pressure P 额 At that time, the vent valve on the top of the individual battery cell is opened.

[0033] Preferably, in some embodiments of this application, the following steps are further included:

[0034] When an abnormal gas production condition is identified, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual cell and the temperature rise rate dT / dt of the temperature T of the individual cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula:

[0035] R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt),

[0036] Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of a single cell, and satisfy w1+w2+w3=1; f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; when R exceeds the first-level thermal runaway risk threshold, a first-level warning is triggered, and when R exceeds the second-level thermal runaway risk threshold, a second-level warning is triggered.

[0037] Preferably, in some embodiments of this application, the following steps are further included:

[0038] When a Level 2 warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

[0039] Preferably, in some embodiments of this application, the heat spread matrix is ​​constructed as follows:

[0040] Taking the coordinates (i0, j0) of the single cell that triggered the secondary warning as the origin, and taking its thermal runaway initiation time as t0, then the expected thermal runaway time interval of any single cell (i, j) in this matrix is... for:

[0041] '

[0042] '

[0043] Where, d x The center-to-center spacing of adjacent rows in the cell array, d y T is the center-to-center spacing between adjacent columns of the cell array. thr The preset thermal runaway critical temperature; T ij α is the measured temperature of a single cell (i,j) at the current moment; α is the thermal diffusivity coefficient; k is the thermal conductivity coefficient of the quartz wool insulation component; Δt is the preset time confidence half-width; when Greater than the preset propagation cutoff distance L max When the corresponding matrix elements are empty, it indicates that thermal runaway will not spread to the individual cell (i,j).

[0044] It should be understood that, within the scope of this application, the above-described technical features of this application and the technical features specifically described below (such as in the embodiments) can be combined with each other to form new or preferred technical solutions. Due to space limitations, they will not be described in detail here.

[0045] Compared with the prior art, this application has the following technical effects:

[0046] This application employs a multi-pronged approach to protection, utilizing cell selection, fiberglass tubing harness protection, quartz wool cell isolation, pressure relief zone routing, and vent valve pressure monitoring. On one hand, it reduces the intensity of thermal runaway from the cell itself, using quartz wool to form a physical thermal barrier to block lateral heat conduction, and high-temperature resistant fiberglass tubing to prevent high-temperature fumes from damaging the wiring harness and causing secondary short-circuit fires. The routing structure, avoiding pressure relief zones, ensures smooth gas release during faults, eliminating the risk of internal pressure buildup and explosion. On the other hand, it relies on a real-time vent valve pressure monitoring system to detect early anomalies in trace amounts of gas generated by the cells, enabling early warning and intervention. This comprehensive multi-layered protection system allows the energy storage module to successfully pass all thermal safety tests according to the UL9540A standard. It effectively addresses the shortcomings of traditional protection schemes, such as limited protection methods, insufficient thermal propagation prevention capabilities, lack of pressure relief safety design, and delayed early fault identification. This significantly improves the safety and stability of the energy storage system throughout its entire lifecycle, making it suitable for various application scenarios, including large and medium-sized energy storage power stations, industrial and commercial energy storage, and residential energy storage. Attached Figure Description

[0047] The above and other features and advantages of this application will become more apparent from a detailed description of exemplary embodiments thereof with reference to the accompanying drawings.

[0048] Figure 1 This paper shows a schematic diagram of the structure of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application;

[0049] Figure 2 A schematic diagram of a quartz wool insulation component arrangement according to an embodiment of this application is shown;

[0050] Figure 3 for Figure 2 A magnified view of a portion of the image;

[0051] Figure 4 This illustration shows a split diagram of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application;

[0052] Figure 5 A perspective view of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application is shown;

[0053] Figure 6 A flowchart of a method for preventing thermal propagation in a lithium battery energy storage module according to an embodiment of this application is shown.

[0054] Reference numerals: 10 Cell array; 11 Cell vent valve; 20 System harness; 30 Harness protection assembly; 40 Pressure relief monitoring unit; 50 Quartz wool insulation assembly; 60 Stainless steel enclosure; 61 Enclosure vent valve.

[0055] The features and advantages of this application will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Throughout the drawings, the same reference numerals identify corresponding elements. In the drawings, the same reference numerals generally indicate the same, functionally similar, and / or structurally similar elements. Detailed Implementation

[0056] 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.

[0057] The terms "first," "second," and similar words used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Words such as "including" or "comprising" mean that the element or object preceding the word encompasses the elements or objects listed after the word and their equivalents, without excluding other elements or objects. Words such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are used only to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0058] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other.

[0059] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the scope of the invention.

[0060] According to one aspect of the present invention, a lithium battery energy storage module with multiple collaborative protection functions is provided.

[0061] Figure 1This illustration shows a schematic diagram of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application. The lithium battery energy storage module with multiple collaborative protection functions of this application includes a cell array 10, a system wiring harness 20, a wiring harness protection component 30, a pressure relief monitoring unit 40, and a quartz wool insulation component 50. The cell array 10 is composed of multiple individual cells arranged in a matrix. Each individual cell is arranged at a predetermined interval in the row and column directions to form a regular array structure, facilitating the placement of isolation components between adjacent cells and reserving a uniform space layout for pressure relief channels. In some embodiments, this application selects a high-safety energy storage-specific lithium iron phosphate battery as the core energy storage unit of the system. Unlike other lithium battery cells such as ternary lithium batteries, the energy storage-grade lithium iron phosphate battery selected in this invention has significant unique advantages in thermal stability, gas generation characteristics, anti-abuse capability, and controllable thermal spread. It can significantly reduce the probability of thermal spread triggering at the cell level and meet the stringent thermal safety testing requirements of the UL9540A standard. Conventional ternary lithium batteries have poor thermal stability in their cathode materials, easily decomposing at around 200℃. This decomposition leads to violent gas production and high explosive intensity after runaway, easily triggering large-scale chain fires and failing the UL9540A thermal spread test. In contrast, the energy storage-specific lithium iron phosphate battery used in this invention has a cathode material decomposition temperature exceeding 800℃, exhibiting extremely high thermal stability. It boasts long cycle life, low charge / discharge temperature rise, gradual gas production rate, and no violent deflagration. Even under abuse conditions such as overcharging, high temperatures, and localized micro-short circuits, it will not instantly experience violent thermal runaway, demonstrating significantly superior fault tolerance compared to other battery types. Furthermore, this type of lithium battery is suitable for the demanding conditions of densely integrated energy storage modules and high-frequency charge / discharge cycles. It exhibits a low heat accumulation rate and uniform aging degradation, allowing for precise detection of early anomalies through gas pressure monitoring, providing ample intervention window for subsequent structural protection and early warning. Several individual lithium batteries are neatly arranged and assembled into a battery module. The cells inside the module are arranged in a matrix and uniformly, with standardized installation gaps reserved, providing a basis for the standardized installation of the subsequent quartz wool insulation structure and air pressure monitoring structure.

[0062] As those skilled in the art will understand, UL 9540A, as the globally authoritative standard for assessing and testing the thermal and fire spread of energy storage systems, has become a core basis for industry safety access. This standard quantifies the risk of thermal spread through a three-tiered progressive testing process involving cells, modules, and units, clearly defining the criteria for judgment: In an environment of 25±5℃ and at full SOC, after a single cell thermal runaway is triggered using standard methods, no chain-reaction spread occurs at the cell, module, unit, or large-scale levels; adjacent equipment shows no open flame, no explosion, and no irreversible damage; and temperature and gas emissions meet the standard limits. The standard limits are: cell valve opening temperature 140–180℃, thermal runaway trigger temperature 240–280℃, temperature rise rate ≥180℃ / min and T≥200℃ for 5 seconds; module casing temperature rise ≤97℃, adjacent cell temperature below valve opening temperature; and adjacent cabinet temperature rise at the unit and site levels ≤97℃ with no flame or explosion spread.

[0063] The core testing logic of the UL9540A standard is to systematically assess the module's risk of lateral flame spread, high-temperature heat conduction and diffusion, pressure buildup due to poor pressure relief, short circuits caused by wiring harness burnout, and explosive combustion of flammable gas by triggering thermal runaway of individual battery cells. It focuses on verifying the fault tolerance and isolation protection capabilities of the energy storage system under single-cell failure conditions. However, the structural design and protection solutions of most lithium battery modules currently on the market are unable to meet the stringent testing requirements of the new UL9540A standard, becoming a core technological barrier for energy storage products to go global and for large-scale energy storage power stations to connect to the grid. Existing energy storage modules generally adopt a dense, sealed cell arrangement structure without specialized flame-retardant isolation, pressure relief protection, and wiring harness risk avoidance design, frequently exhibiting typical failure problems in UL9540A thermal runaway simulation tests. In response to the stringent assessment requirements of the new UL9540A-2025 standard, the industry urgently needs a proactive thermal runaway prevention solution that is compatible with the standard's testing specifications and addresses issues such as heat spread, wiring harness damage, pressure relief failures, and early detection failures at the structural level. Based on the core testing points and compliance pain points of the UL9540A standard, this application specifically designs a multi-protection system including lithium battery selection, fiberglass tubing harness protection, quartz wool cell isolation, pressure relief area avoidance wiring, and pressure monitoring of the vent valve. It precisely solves the technical problems of existing technologies not meeting the UL9540A thermal safety assessment and fully meets international energy storage safety compliance standards.

[0064] System harness 20 is used for high-power power transmission, communication signal interaction, or data acquisition. Specifically, system harness 20 is used to realize high-power power transmission, communication signal interaction, or cell data acquisition within the energy storage module. In some embodiments, system harness 20 includes a high-voltage power harness, a low-voltage signal harness, and a sampling harness. The high-voltage power harness is used to realize the transmission of high-power power between various high-voltage components of the energy storage battery system, constructing the main power circuit for battery charging and discharging. The low-voltage signal harness is used to transmit control commands, equipment feedback signals, and low-voltage power supply signals, completing communication interaction and device drive control between various electrical components. The sampling harness is electrically connected to the battery module and the BMS acquisition board respectively, used to acquire cell voltage and temperature signals, so that the BMS can complete battery status monitoring, fault identification, and equalization control.

[0065] The wiring harness protection assembly 30 includes multiple fiberglass tubes, which are woven from alkali-free glass fiber with dense, non-porous walls. All system wiring harnesses 20 are threaded through these fiberglass tubes, achieving full coverage protection. In some embodiments, the fiberglass tubes are sleeved along the routing direction of the system wiring harnesses 20, with their inner diameter matching the outer diameter of the wiring harnesses, ensuring the outer wall of the wiring harness fits snugly against the inner wall of the fiberglass tube. This isolates the wiring harness insulation layer from direct impact by high-temperature gases and molten materials during thermal runaway and pressure relief of individual battery cells. Furthermore, this application selects high-temperature resistant, flame-retardant fiberglass tubes as the outer protective structure for the wiring harnesses, securing all wiring harnesses inside the fiberglass tubes. The fiberglass tube is made of alkali-free glass fiber woven into a dense, non-porous structure. It possesses excellent high-temperature resistance, flame retardancy, heat insulation, burn resistance, and electrical insulation properties. It can withstand temperatures above 600℃ for extended periods and short-term exposure to fumes exceeding 1000℃. It completely isolates the wire harness from the high temperatures, molten materials, and open flames generated by the heat spread from the battery cell, preventing damage to the insulation layer and short circuits. Simultaneously, the fiberglass tube exhibits good flexibility, adapting to the bending layout requirements of the wire harness without affecting the module assembly accuracy.

[0066] The pressure relief monitoring unit 40 includes multiple miniature pressure sensors and a BMS communicating with the miniature pressure sensors. Each miniature pressure sensor is correspondingly installed at the outlet of the vent valve of a single battery cell to collect the pressure signal at the vent valve in real time. The sampling end of the miniature pressure sensor faces the outlet direction of the vent valve to ensure that the pressure change before and after the vent valve is opened can be captured.

[0067] As those skilled in the art will understand, each miniature pressure sensor is connected to the BMS to construct a comprehensive pressure relief status monitoring network. The miniature pressure sensors collect real-time pressure values ​​and pressure change rate data at the vent valve ports. The BMS system has built-in multi-level early warning thresholds, which can accurately identify different states of a single battery cell, such as normal static state, normal charging and discharging with trace amounts of gas, abnormal fault gas generation, and pressure relief blockage, thereby achieving accurate prediction and early warning of early-stage thermal propagation faults.

[0068] Figure 2 A schematic diagram of a quartz wool insulation component arrangement according to an embodiment of this application is shown. Figure 3 for Figure 2 A partial enlarged view shows that a quartz wool insulation component 50 is vertically arranged between two adjacent individual cells. The quartz wool insulation component 50 completely covers the height and width of the sidewall of the individual cell, providing flame retardant and heat insulation, and achieving complete physical isolation between adjacent individual cells. A no-wiring safety zone is defined with the center of the vent valve at the top of any individual cell as a reference. A fiberglass tube carrying the system wiring harness 20 is arranged outside the no-wiring safety zone to avoid the pressure relief channel of the vent valve. Furthermore, the quartz wool insulation component 50 of this application is made of high-purity quartz material pressed and sintered into quartz wool, which has extremely low thermal conductivity, ultra-high temperature resistance, and absolute flame retardant properties. It is non-combustible, non-melting, and non-conductive, effectively blocking the lateral heat conduction during individual cell failures, preventing adjacent cells from being preheated by high temperatures, and structurally cutting off the heat spread path. At the same time, the quartz wool has insulating properties, preventing short-circuit faults caused by contact between the cell sidewalls.

[0069] Specifically, in terms of spatial layout, a no-wiring safety zone is defined with the center of the vent valve on the top of any individual battery cell as the reference. A fiberglass tube carrying the system wiring harness 20 is arranged outside this no-wiring safety zone to avoid the pressure relief channel of the vent valve. The no-wiring safety zone refers to the area defined based on the center of the vent valve, according to the vent valve's spray angle and pressure relief range. No wiring harnesses or protective components are arranged within this area to ensure that high-temperature gas can be discharged unimpeded when the vent valve is opened, preventing high-pressure gas from impacting the wiring harness and causing protection failure.

[0070] Preferably, in some embodiments of this application, a dedicated wiring plan is implemented based on the installation location of the lithium battery vent valve. All fiberglass-coated wire harnesses avoid the vertical pressure relief area and lateral diffusion area of ​​the vent valve at the top of the individual battery cell. A preset safe pressure relief range for the vent valve is defined, with the center of the vent valve of a single battery cell as the reference, delineating a 50mm radial and 80mm axial no-wiring safe zone. All power and signal wire harnesses are routed around to the outside of the safe zone, with no wire harnesses obstructing or crossing the pressure relief channel, ensuring unobstructed normal pressure relief and emergency pressure relief of the battery cell, while preventing high-temperature pressure relief airflow from eroding and damaging the wire harnesses.

[0071] The BMS is configured to perform the following bar pressure monitoring and operating condition determination logic:

[0072] The BMS presets a first pressure rate threshold, a second pressure rate threshold, a first-level thermal runaway risk threshold, and a second-level thermal runaway risk threshold. The first pressure rate threshold is lower than the second pressure rate threshold, corresponding to the boundary point of pressure change rate between normal gas production and abnormal gas production, respectively. The first-level thermal runaway risk threshold is lower than the second-level thermal runaway risk threshold, corresponding to the trigger levels of early warning and severe early warning, respectively.

[0073] The Battery Management System (BMS) collects the time-series pressure signals from each miniature pressure sensor and calculates the first-order rate of change of pressure (dp / dt) and the second-order rate of change of pressure (d²p / dt²) based on these signals. Here, p represents pressure, t represents time, dp represents the infinitesimal change in pressure, and dt represents the infinitesimal change in time. The first-order rate of change reflects the speed of pressure increase, while the second-order rate of change reflects the trend of the pressure increase rate (i.e., acceleration). When dp / dt is below the first pressure rate threshold and d²p / dt² is less than the preset acceleration threshold, the BMS determines it as a normal gas production condition. This condition corresponds to the situation where a small amount of gas is generated due to internal chemical reactions during normal charging and discharging of the battery cell, with a smooth pressure change and no acceleration trend. When dp / dt exceeds the second pressure rate threshold and d²p / dt² remains positive for a preset duration, the BMS determines it as an abnormal gas production condition. This condition corresponds to a side reaction or a precursor to thermal runaway occurring inside the battery cell, with a rapid and continuous increase in pressure. When the accumulated air pressure rises and d²p / dt² turns from positive to negative, and the air pressure value p is higher than the preset high pressure threshold within the preset high pressure holding time, the BMS determines it to be a pressure relief blockage condition. This condition corresponds to the air relief valve failing to open normally or the exhaust channel being blocked, and the air pressure failing to drop quickly after reaching the peak, remaining in a high pressure state.

[0074] Preferably, in some embodiments, the BMS also calculates the internal gas pressure P of a single cell based on the following formula. 内 ;

[0075] P 内 =nRT / V0,

[0076] Where n is the amount of substance of the gas inside a single cell, in mol; R is the molar gas constant; T is the temperature of the single cell, collected by a temperature sensor located on or inside the single cell; V0 is the free volume inside the single cell; when P is calculated... 内 Greater than or equal to the preset rated valve opening pressure P 额 When the pressure is high, the BMS commands the top vent valve of the individual cell to open, actively triggering pressure relief to prevent the internal pressure from continuously rising and causing the cell casing to rupture. The rated valve opening pressure of energy storage lithium batteries is generally calibrated at 150 kPa. This active valve opening control is redundant with the passive mechanical opening mechanism of the vent valve, so that pressure relief can still be achieved through electronic control even if the passive mechanism fails.

[0077] As those skilled in the art will understand, when a lithium battery ages, short-circuits, or experiences thermal runaway, the internal electrolyte and electrode materials decompose, continuously generating gas. With the cell volume remaining constant, the pressure (n) increases, the temperature rises, and the internal gas pressure continues to rise. When the internal pressure (P_internal) exceeds or equals the preset rated opening pressure (P_rated), the vent valve opens. After the cell vent valve opens, the gas released from the cell accumulates inside the battery casing. If not quickly released, the gas will build up. Excessive gas pressure can cause the cell inside the casing to catch fire and explode. When the gas pressure reaches a certain level, it will force open the vent valve of the casing, completing the overall venting process.

[0078] Preferably, in some embodiments of this application, the BMS is further configured as follows:

[0079] When an abnormal gas production condition is identified, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual cell and the temperature rise rate dT / dt of the temperature T of the individual cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula:

[0080] R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt),

[0081] Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of a single cell, and satisfying w1+w2+w3=1; the preset weighting table stores weighting coefficient combinations corresponding to different SOC intervals: in the high SOC interval, the weight w2 of the voltage drop rate is increased accordingly; in the low SOC interval, the weight w1 of the pressure change rate is increased accordingly, to adapt to the sensitivity differences of thermal runaway characteristic parameters under different charging states. f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; after each input parameter is mapped to the [0,1] interval, the comprehensive risk index R is obtained by weighted summation. When R exceeds the first-level thermal runaway risk threshold, the BMS triggers a first-level warning; when R exceeds the second-level thermal runaway risk threshold, the BMS triggers a second-level warning. The first-level warning can correspond to audible and visual prompts or power reduction operation, and the second-level warning can correspond to cutting off the charging and discharging circuit or activating fire alarm linkage.

[0082] Preferably, in some embodiments of this application, the BMS is further configured as follows:

[0083] When a Level 2 warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array 10, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

[0084] Preferably, in some embodiments of this application, the heat spread matrix is ​​constructed as follows:

[0085] Taking the coordinates (i0, j0) of the single cell that triggered the secondary warning as the origin, and taking its thermal runaway initiation time as t0, then the expected thermal runaway time interval of any single cell (i, j) in this matrix is... for:

[0086] '

[0087] '

[0088] Where, d x The center-to-center spacing of adjacent rows of the cell array 10, d y T is the center-to-center spacing of 10 adjacent columns in the cell array. thr The preset thermal runaway critical temperature; T ij α is the measured temperature of a single cell (i,j) at the current moment; α is the thermal diffusivity coefficient; k is the thermal conductivity coefficient of the quartz wool insulation component 50; Δt is the preset time confidence half-width; when Greater than the preset propagation cutoff distance L max When the corresponding matrix elements are empty, it indicates that thermal runaway will not propagate to the individual cell (i,j). The propagation cutoff distance L max Based on the thermal insulation performance of the quartz wool insulation components and the array spacing settings, individual cells exceeding this distance are not affected by this thermal runaway event.

[0089] Figure 4 This illustration shows a split diagram of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application; Figure 5 This illustration shows a perspective view of a lithium battery energy storage module with multiple collaborative protection functions according to an embodiment of this application. In some embodiments, the energy storage module further includes a stainless steel housing 60, which has a pre-reserved overall pressure relief channel for discharging flammable high-temperature gases released from the vent valves of each individual battery cell. The overall pressure relief channel is fluidly connected to the outlet of the vent valve of each individual battery cell, allowing the depressurized gas to collect along a unified channel and then be discharged to the outside of the housing through the housing vent valve 61, preventing high-temperature gas from accumulating inside the housing and causing secondary hazards. The housing of this application is made entirely of stainless steel, which has the advantages of high temperature resistance and deformation resistance.

[0090] According to another aspect of this application, this application also provides a method for preventing thermal propagation in lithium battery energy storage modules, which is implemented based on the energy storage module described in any of the above embodiments.

[0091] Figure 6 This is a flowchart of a method for preventing thermal runaway in a lithium battery energy storage module according to the present invention. (Reference) Figure 6, Figure 6 The method shown includes steps S101 to S111.

[0092] Step S101, Single cell array arrangement: Multiple single cells are arranged in a matrix to form a cell array 10;

[0093] Step S102, System wiring harness protection: The system wiring harness 20 is threaded through the fiberglass tube to complete full coverage protection; in step S102, the fiberglass tube is woven from alkali-free glass fiber and the tube wall is dense and without pores;

[0094] Step S103, Individual cell isolation setting: A quartz wool isolation component 50 is vertically set between two adjacent individual cells so that the quartz wool isolation component 50 completely covers the height and width directions of the individual cell sidewall.

[0095] Step S104, Pressure relief zone avoidance setting: Based on the center of the vent valve on the top of any single cell, a no-wiring safety zone is defined. The fiberglass tube through which the system wiring harness 20 is installed is placed outside the no-wiring safety zone to avoid the pressure relief channel of the vent valve.

[0096] Step S105, Pressure relief monitoring and early warning: A miniature pressure sensor is installed at the outlet of the vent valve of each individual cell, and all miniature pressure sensors are connected to the BMS for communication.

[0097] Step S106: The BMS presets the first pressure rate threshold, the second pressure rate threshold, the first-level thermal runaway risk threshold, and the second-level thermal runaway risk threshold.

[0098] Step S107: Collect the air pressure timing signals of each miniature air pressure sensor;

[0099] Step S108: Calculate the first-order rate of change of air pressure dp / dt and the second-order rate of change of air pressure d²p / dt², where p is air pressure, t is time, dp represents the infinitesimal change of air pressure, and dt represents the infinitesimal change of time.

[0100] Step S109: When dp / dt is lower than the first gas pressure rate threshold and d²p / dt² is less than the preset acceleration judgment threshold, it is determined to be a normal gas production condition.

[0101] Step S110: When dp / dt exceeds the second gas pressure rate threshold and d²p / dt² remains positive within the preset continuous judgment time, it is judged as an abnormal gas production condition.

[0102] Step S111: When the accumulated air pressure rises and d²p / dt² changes from positive to negative, and the air pressure value p is higher than the preset high pressure threshold within the preset high pressure holding time, it is determined to be a pressure relief blockage condition.

[0103] Preferably, in some embodiments of this application, the method further includes the following steps:

[0104] BMS calculates the internal air pressure P of a single battery cell based on the following formula. 内 ;

[0105] P 内 =nRT / V0,

[0106] Where n is the amount of substance of the gas inside a single cell, in mol; R is the molar gas constant; T is the temperature of the single cell; and V0 is the free volume inside the single cell.

[0107] When P 内 Greater than or equal to the preset rated valve opening pressure P 额 At that time, the vent valve on the top of the individual battery cell is opened.

[0108] Preferably, in some embodiments of this application, the following steps are further included:

[0109] When an abnormal gas production condition is identified, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual cell and the temperature rise rate dT / dt of the temperature T of the individual cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula:

[0110] R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt),

[0111] Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of a single cell, and satisfy w1+w2+w3=1; f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; when R exceeds the first-level thermal runaway risk threshold, a first-level warning is triggered, and when R exceeds the second-level thermal runaway risk threshold, a second-level warning is triggered.

[0112] Preferably, in some embodiments of this application, the following steps are further included:

[0113] When a Level 2 warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array 10, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

[0114] Preferably, in some embodiments of this application, the heat spread matrix is ​​constructed as follows:

[0115] Taking the coordinates (i0, j0) of the single cell that triggered the secondary warning as the origin, and taking its thermal runaway initiation time as t0, then the expected thermal runaway time interval of any single cell (i, j) in this matrix is... for:

[0116] '

[0117] '

[0118] Where, d x The center-to-center spacing of adjacent rows of the cell array 10, d y T is the center-to-center spacing of 10 adjacent columns in the cell array. thr The preset thermal runaway critical temperature; T ij α is the measured temperature of a single cell (i,j) at the current moment; α is the thermal diffusivity coefficient; k is the thermal conductivity coefficient of the quartz wool insulation component 50; Δt is the preset time confidence half-width; when Greater than the preset propagation cutoff distance L max When the corresponding matrix elements are empty, it indicates that thermal runaway will not propagate to the individual cell (i,j). The propagation cutoff distance L max Based on the thermal insulation performance of the quartz wool insulation components and the array spacing settings, individual cells exceeding this distance are not affected by this thermal runaway event.

[0119] In summary, this invention, through the coordinated efforts of multiple protections including structural flame retardancy, physical isolation, wiring risk avoidance, and condition monitoring, avoids risks such as short-circuit fires, heat crosstalk, pressure relief obstruction, and abnormal gas generation and heat accumulation in lithium batteries from the source. It effectively blocks the path of heat spread from individual cells to the entire module and battery cluster, solving the technical pain points of existing lithium battery systems such as single protection, rapid heat spread, inability to identify pressure relief faults in a timely manner, and easy damage to wiring harnesses by high-temperature flue gas. It significantly improves the safety and stability of lithium battery systems throughout their entire life cycle and is suitable for the safety protection of various large and medium-sized electrochemical energy storage power stations, industrial and commercial energy storage, and residential energy storage equipment. It has extremely high practicality and adaptability.

[0120] The preferred embodiments of this application have been described above. It should be understood that this application is not limited to the specific embodiments described above, and the devices and structures not described in detail should be understood as being implemented in a conventional manner in the art. Any person skilled in the art can make many possible variations and modifications to the technical solutions of this application using the methods and techniques disclosed above, or modify them into equivalent embodiments with equivalent changes, without departing from the scope of the technical solutions of this application. This does not affect the substantive content of this application. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this application without departing from the content of the technical solutions of this application still fall within the protection scope of the technical solutions of this application.

Claims

1. A lithium battery energy storage module with multiple collaborative protection functions, characterized in that, include: A cell array is composed of multiple individual cells arranged in a uniform matrix. System harnesses are used for high-power power transmission, communication signal interaction, or data acquisition. The wire harness protection assembly includes multiple fiberglass tubes, which are woven from alkali-free glass fibers and have dense, non-porous walls; the system wire harnesses are all inserted into the fiberglass tubes to achieve full coverage protection. The pressure relief monitoring unit includes multiple miniature pressure sensors and a BMS that is communicatively connected to the miniature pressure sensors. The miniature pressure sensors are respectively installed at the outlet end of the vent valve of the individual battery cell. A quartz wool insulating assembly is vertically arranged between two adjacent individual cells, and the quartz wool insulating assembly completely covers the height and width directions of the sidewall of the individual cell; A no-wiring safety zone is defined with the center of the vent valve on the top of any of the individual cells as a reference. The fiberglass tube through which the system wiring harness is threaded is arranged outside the no-wiring safety zone to avoid the pressure relief channel of the vent valve. The BMS is configured as follows: Preset first pressure rate threshold, second pressure rate threshold, first-level thermal runaway risk threshold and second-level thermal runaway risk threshold; Collect the air pressure timing signals of each of the aforementioned miniature air pressure sensors; Calculate the first-order rate of change of air pressure dp / dt and the second-order rate of change of air pressure d²p / dt², where p is air pressure, t is time, dp represents the infinitesimal change in air pressure, and dt represents the infinitesimal change in time. When dp / dt is lower than the first gas pressure rate threshold and d²p / dt² is less than the preset acceleration judgment threshold, it is determined to be a normal gas production condition. When dp / dt exceeds the second gas pressure rate threshold and d²p / dt² remains positive within the preset continuous judgment time, it is judged as an abnormal gas production condition. When the accumulated air pressure increases and d²p / dt² changes from positive to negative, and the air pressure value p is higher than the preset high pressure threshold within the preset high pressure holding time, it is determined to be a pressure relief blockage condition.

2. The energy storage module according to claim 1, characterized in that, The BMS also calculates the internal air pressure P of the individual battery cell based on the following formula. 内 ; P 内 =nRT / V0, Wherein, n is the amount of substance of the gas inside the single cell, in mol; R is the molar gas constant; T is the temperature of the single cell; and V0 is the free volume inside the single cell. When the P 内 Greater than or equal to the preset rated valve opening pressure P 额 At that time, the vent valve on the top of the individual battery cell is opened.

3. The energy storage module according to claim 1, characterized in that, The BMS is also configured as follows: When an abnormal gas production condition is determined, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual battery cell and the temperature rise rate dT / dt of the temperature T of the individual battery cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula: R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt), Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of the individual cell, and satisfy w1+w2+w3=1; f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; when R exceeds the first-level thermal runaway risk threshold, a first-level warning is triggered, and when R exceeds the second-level thermal runaway risk threshold, a second-level warning is triggered.

4. The energy storage module according to claim 3, characterized in that, The BMS is also configured as follows: When the secondary warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

5. The energy storage module according to claim 1, characterized in that, The energy storage module also includes a stainless steel housing, which has a pre-reserved overall pressure relief channel for discharging flammable high-temperature gases released by the vent valves of each individual battery cell.

6. A method for preventing thermal propagation in lithium battery energy storage modules, characterized in that, The prevention method, applied to the energy storage module according to any one of claims 1 to 5, comprises: Single cell array arrangement: Multiple single cells are arranged in a matrix to form a cell array; System wiring harness protection: The system wiring harness is threaded through the fiberglass tube to achieve full coverage protection; Individual cell isolation setup: The quartz wool isolation assembly is vertically arranged between two adjacent individual cells, so that the quartz wool isolation assembly completely covers the height and width directions of the sidewall of the individual cell; Pressure relief zone avoidance setting: A no-wiring safety area is defined with the center of the vent valve on the top of any of the individual cells as a reference. The fiberglass tube through which the system wiring harness is threaded is arranged outside the no-wiring safety area to avoid the pressure relief channel of the vent valve. Pressure relief monitoring and early warning: The miniature pressure sensor is installed at the outlet of the vent valve of each individual cell, and all the miniature pressure sensors are connected to the BMS. The BMS has preset a first pressure rate threshold, a second pressure rate threshold, a first-level thermal runaway risk threshold, and a second-level thermal runaway risk threshold. The system collects the time-series signals of the micro pressure sensors; calculates the first-order rate of change of pressure dp / dt and the second-order rate of change of pressure d²p / dt², where p is the pressure, t is the time, dp represents the infinitesimal change in pressure, and dt represents the infinitesimal change in time; when dp / dt is lower than the first pressure rate threshold and d²p / dt² is less than a preset acceleration threshold, it is determined to be a normal gas production condition; when dp / dt exceeds the second pressure rate threshold and d²p / dt² remains positive for a preset duration, it is determined to be an abnormal gas production condition; when the pressure accumulates and d²p / dt² changes from positive to negative, and the pressure value p is higher than a preset high pressure threshold for a preset high pressure holding time, it is determined to be a pressure relief blockage condition.

7. The prevention method according to claim 6, characterized in that, It also includes the following steps: The BMS calculates the internal air pressure P of the individual battery cell based on the following formula. 内 ; P 内 =nRT / V0, Wherein, n is the amount of substance of the gas inside the single cell, in mol; R is the molar gas constant; T is the temperature of the single cell; and V0 is the free volume inside the single cell. When the P 内 Greater than or equal to the preset rated valve opening pressure P 额 At that time, the vent valve on the top of the individual battery cell is opened.

8. The prevention method according to claim 6, characterized in that, It also includes the following steps: When an abnormal gas production condition is determined, the BMS retrieves the voltage drop rate |dV / dt| of the voltage V of the same individual battery cell and the temperature rise rate dT / dt of the temperature T of the individual battery cell, where dV / dt represents the rate of change of voltage V with respect to time t, and dT / dt represents the rate of change of temperature T with respect to time t. The thermal runaway risk index R is calculated according to the following dynamic weighted formula: R = w1·f(dp / dt) + w2·f(|dV / dt|) + w3·f(dT / dt), Where w1, w2, and w3 are weighting coefficients dynamically selected from a preset weighting table based on the current SOC value of the individual cell, and satisfy w1+w2+w3=1; f() is a piecewise linear mapping function that normalizes the input parameters to the [0,1] interval; when R exceeds the first-level thermal runaway risk threshold, a first-level warning is triggered, and when R exceeds the second-level thermal runaway risk threshold, a second-level warning is triggered.

9. The prevention method according to claim 8, characterized in that, It also includes the following steps: When the secondary warning is triggered, the BMS calculates the expected thermal runaway time interval of each adjacent cell based on the matrix arrangement coordinates of the cell array, with the cell that triggered the warning as the center, according to the preset thermal propagation matrix.

10. The prevention method according to claim 9, characterized in that, The heat propagation matrix is ​​constructed as follows: Taking the coordinates (i0, j0) of the individual cell that triggered the secondary warning as the origin, and taking its thermal runaway initiation time as t0, then the expected thermal runaway time interval of any individual cell (i, j) in this matrix is... for: ’ ’ Where, d x The center-to-center spacing of adjacent rows in the cell array, d y T is the center-to-center spacing between adjacent columns of the cell array. thr The preset thermal runaway critical temperature; T ij α is the measured temperature of a single cell (i,j) at the current moment; α is the thermal diffusivity coefficient; k is the thermal conductivity coefficient of the quartz wool insulation component; Δt is the preset time confidence half-width; when Greater than the preset propagation cutoff distance L max When the corresponding matrix elements are empty, it indicates that thermal runaway will not spread to the single cell (i,j).

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