Coal mine underground lithium battery system with thermal runaway protection function

Abstract

The invention provides an underground coal mine lithium battery system with a thermal runaway protection function. The underground coal mine lithium battery system comprises an intelligent grading early warning subsystem, a linkage control subsystem, a high-pressure pulse fire extinguishing execution subsystem and an anti-explosion inert gas injection system. And the water-based fire extinguishing agent is driven to circularly flow in the closed-loop channel in the first-stage early warning stage. And in the second-stage early warning stage, the thin-film thermoelectric generator array converts the physical temperature difference generated by the battery cells of the single batteries into transient high-voltage direct current to drive the solid-state electroosmosis micropump array to break down the rupture film, so that the water-based fire extinguishing agent is injected into the battery cells in a transient pulse jet form. And in the third-stage early warning stage, the external macroscopic high-voltage pulse execution unit implements reciprocating scanning injection and is matched with the anti-explosion inert gas injection system to inject high-pressure inert gas into the battery pack so as to establish an inert environment through a gas replacement effect. According to the invention, the safety of the underground lithium battery system is improved through an internal and external cooperative grading protection mechanism.

Description

Technical Field

[0001] This invention relates to the field of lithium battery safety protection technology, specifically to an underground lithium battery system for coal mines with thermal runaway protection function. Background Technology

[0002] Trackless rubber-wheeled vehicles and energy storage power stations in coal mines widely use high-energy-density lithium batteries as their power source. The safe operation of lithium battery systems is crucial to ensuring the mine production environment.

[0003] Existing safety protection technologies for lithium batteries in underground coal mines typically rely on battery management systems to monitor the voltage and temperature of individual battery cells in real time, combined with externally deployed fire extinguishing equipment for fire prevention. When abnormal battery conditions are detected, traditional systems mainly rely on passive protection through electrical fuses, or utilize dry powder or gas spray devices located in the chamber and outside the battery box to carry out large-area cooling and fire suppression actions on the external space of the battery pack.

[0004] Traditional underground lithium battery safety protection technologies in coal mines suffer from a single response mode and a disconnect between internal cooling and external protection logic when dealing with the entire process of thermal runaway. Due to the lack of a gradient coordination mechanism from internal microscopic in-situ cooling to external macroscopic full-coverage fire suppression, the system cannot implement targeted graded control at different stages of battery thermal runaway, such as latency, triggering, and propagation. Especially in the confined space of underground coal mines, a single external spraying method is difficult to penetrate into the densely stacked battery clusters to suppress hidden hot spots, which can easily create blind spots in the handling and cause local temperature rise accidents to evolve into uncontrollable large-scale fires and explosions in a short period of time. Summary of the Invention

[0005] The first aspect of the present invention provides a coal mine underground lithium battery system with thermal runaway protection function, including: an intelligent graded early warning subsystem, a linkage control subsystem, and a high-voltage pulse fire extinguishing execution subsystem.

[0006] The intelligent graded early warning subsystem is equipped with a multi-parameter sensor array and a data analysis and grading unit. The multi-parameter sensor array is distributed inside the battery pack to collect battery status parameters. The data analysis and grading unit is communicatively connected to the multi-parameter sensor array to output thermal runaway risk level signals. The linkage control subsystem is connected to the intelligent graded early warning subsystem, receives the thermal runaway risk level signals, and generates control commands.

[0007] The high-pressure pulse fire suppression execution subsystem is connected to the linkage control subsystem and includes an external macroscopic high-pressure pulse execution unit and an internal microfluidic pulse execution unit. The internal microfluidic pulse execution unit includes a thermal management partition, a microcapillary network, a solid electroosmotic micropump array, a water-based fire extinguishing agent, a thin-film thermoelectric generator array, and a rupture membrane. The thermal management partition is positioned between the individual battery cells. The microcapillary network is embedded within the thermal management partition. The solid electroosmotic micropump array is positioned within the fluid circulation channels of the microcapillary network.

[0008] A thin-film thermoelectric generator array is positioned between the sidewall of the individual battery cell and the thermal management separator. The hot end of the thin-film thermoelectric generator array is attached to the sidewall of the individual battery cell, and the cold end is attached to the outer sidewall of the thermal management separator. The power output of the thin-film thermoelectric generator array is electrically connected to the power input of the solid-state electroosmotic micropump array via a unidirectional isolation module. A ruptured membrane is positioned on the sidewall of the channel corresponding to the location of the microcapillary network on the sidewall of the individual battery cell.

[0009] The second aspect of this invention provides an operation process for an underground lithium battery system in a coal mine with thermal runaway protection:

[0010] Upon receiving a Level 1 warning signal, the linkage control subsystem outputs a DC signal to the solid-state electroosmotic micro-pump array. Under the action of the DC electric field, the solid-state electroosmotic micro-pump array drives the water-based fire extinguishing agent to circulate within the micro-capillary network, ionizing the heat on the surface of the individual battery cells through forced convection. Simultaneously, the rotating positioning nozzle of the external macroscopic high-voltage pulse actuator is aimed at the target battery area and sprays in a fine water mist mode.

[0011] Upon receiving a secondary warning signal, the linkage control subsystem cuts off the power supply circuit to the battery cell. The surface temperature of the battery cell rises, creating a physical temperature difference between the hot and cold ends of the thin-film thermoelectric generator array. Based on the Seebeck effect, the thin-film thermoelectric generator array converts this physical temperature difference into transient high-voltage direct current. This transient high-voltage direct current is transmitted to the solid-state electroosmotic micropump array through a unidirectional isolation module. The solid-state electroosmotic micropump array establishes a transient high-voltage electric field within the microcapillary network, driving the water-based fire extinguishing agent to generate hydrodynamic pressure. When the hydrodynamic pressure exceeds the physical yield pressure threshold of the rupture membrane, the rupture membrane ruptures. The water-based fire extinguishing agent is then sprayed onto the surface of the battery cell in the form of a transient pulse jet. During the secondary warning process, the thermal energy of the battery cell is absorbed by the thin-film thermoelectric generator array and converted into the jetting force that drives the water-based fire extinguishing agent to break through the rupture membrane.

[0012] Upon receiving a Level 3 warning signal, the linkage control subsystem controls the external macroscopic high-pressure pulse actuator to enter full-power continuous spray mode. The rotating positioning nozzle switches to water jet mode and performs reciprocating mechanical scanning motion within a preset angle range. Simultaneously, the linkage control subsystem activates the explosion-proof inert gas injection system. High-pressure inert gas is released from the inert gas storage tank and enters the battery pack casing. The air inside the battery pack is replaced by the high-pressure inert gas and discharged through the explosion-proof pressure relief valve on the battery pack casing.

[0013] This invention achieves graded suppression of battery thermal runaway by coordinating the operation of a built-in microfluidic pulse execution unit and an external macroscopic high-voltage pulse execution unit. It utilizes a thin-film thermoelectric generator array to convert the thermal energy during abnormal battery temperature rise into the driving force for microfluidic injection, eliminating dependence on external power supply and mechanical response delay. Furthermore, this invention combines directional pulse injection with redundant space inert gas filling, improving the fire and explosion suppression capabilities of lithium battery systems in confined spaces in underground coal mines.

[0014] This invention provides a lithium battery system for underground coal mines with thermal runaway protection. It offers the following advantages: 1. This invention monitors the status data of individual battery cells in real time through a multi-parameter sensor array and outputs three-level early warning signals through a data analysis and grading unit. It coordinates the internal heat transfer and cooling action of the built-in microfluidic pulse execution unit and the external environmental spraying action of the external macroscopic high-voltage pulse execution unit. This achieves graded control and targeted suppression of lithium battery systems in coal mines from the potential risk period to the fire and explosion period. It avoids the monitoring blind spots of single defense methods when dealing with complex thermal runaway evolution processes in confined spaces, and significantly reduces the physical risk of battery modules transforming into large-scale fires during abnormal temperature rise stages.

[0015] 2. This invention arranges a thin-film thermoelectric generator array between the sidewall of a battery cell and the thermal management separator, and converts the generated physical temperature difference into transient high-voltage direct current to drive a solid electroosmotic micropump array to generate fluid dynamic pressure. The generated dynamic pressure breaks down the ruptured membrane pre-set on the sidewall of the microcapillary network, so that the water-based fire extinguishing agent is directly injected into the surface of the abnormal cell in the form of a transient pulse jet. This invention achieves an in-situ suppression effect that utilizes the thermal energy released by thermal runaway to trigger a self-triggering response under extreme conditions such as external power cut-off or control circuit failure. This eliminates the problem of physical response lag in traditional mechanical actuators when dealing with the violent chemical reaction chain of the battery in a very short time.

[0016] 3. This invention utilizes an external macroscopic high-pressure pulse execution unit with a rotating positioning nozzle to perform reciprocating mechanical scanning motion in water jet mode. This, combined with an explosion-proof inert gas injection system, injects high-pressure inert gas into the redundant space inside the battery pack casing to replace the internal air. Combined with a built-in microfluidic pulse execution unit providing precise pulse jet coverage at the individual battery cell level, this invention achieves a three-dimensional, synergistic protection effect within the confined space of an underground coal mine. This includes suppression within individual cells, cooling of the battery cluster surface, and overall explosion suppression of the battery pack. It effectively blocks the physical path of open flames spreading to adjacent equipment and the external gas environment, ensuring the safe operation of the battery compartment in large energy storage power stations under extremely high energy densities. Attached Figure Description

[0017] Figure 1 This is a block diagram of the overall system structure of the present invention; Figure 2 This is a schematic diagram of the hardware communication topology of the present invention; Figure 3 This is a schematic diagram of the built-in thermoelectric coupling self-powered pulse breakdown structure of the present invention. Detailed Implementation

[0018] The technical solutions in 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.

[0019] Please see the appendix Figure 1 -Appendix Figure 3 This invention provides a lithium battery system for underground coal mines with thermal runaway protection, including an intelligent graded early warning subsystem, a linkage control subsystem, and a high-voltage pulse fire suppression execution subsystem. The high-voltage pulse fire suppression execution subsystem includes an external macroscopic high-voltage pulse execution unit and an internal microfluidic pulse execution unit.

[0020] The intelligent graded early warning subsystem is used to monitor the state parameters of lithium-ion batteries in real time and to grade the thermal runaway risk based on a multi-parameter fusion analysis model. The intelligent graded early warning subsystem includes a multi-parameter sensor array and a data analysis and grading unit. The multi-parameter sensor array is located inside the battery pack and at key ventilation points. The multi-parameter sensor array includes temperature sensors, gas sensors, pressure sensors, and voltage and current monitoring modules. The gas sensors are used to monitor carbon monoxide and hydrogen concentrations. The data analysis and grading unit communicates with the multi-parameter sensor array, receives data from the array, and outputs the thermal runaway risk level.

[0021] The linkage control subsystem connects to the data analysis and grading unit to receive grading signals from the intelligent grading and early warning subsystem and generate corresponding control commands. The linkage control subsystem includes an explosion-proof programmable logic controller (PLC) and a communication module. The explosion-proof PLC has a hard-wired interface for connecting to the downhole monitoring center. The control response time of the linkage control subsystem is less than 3 seconds.

[0022] The high-pressure pulse fire suppression execution subsystem is connected to the linkage control subsystem, receiving control commands generated by the linkage control subsystem to execute fire suppression or cooling actions. The external macroscopic high-pressure pulse execution unit includes an extinguishing agent storage tank, a high-pressure power unit, a pulse jet valve assembly, and a rotary positioning nozzle. The extinguishing agent storage tank has a volume greater than or equal to 50 liters. The high-pressure power unit consists of a plunger pump driven by an explosion-proof motor or a pressurized inert gas storage tank. The pulse jet valve assembly includes a high-speed solenoid valve. The rotary positioning nozzle has a built-in stepper motor that receives control signals to adjust the horizontal and vertical angles. At a working pressure greater than or equal to 1.2 MPa, the rotary positioning nozzle sprays the extinguishing agent over a distance greater than or equal to 10 meters, with a pulse jet interval of less than or equal to 3 seconds.

[0023] The built-in microfluidic pulse execution unit includes a thermal management separator, a solid-state electroosmotic micropump array, a thin-film thermoelectric generator array, and a rupture membrane. The thermal management separator contains a microcapillary network. The thermal management separator is positioned between the individual battery cells. The solid-state electroosmotic micropump array is positioned within the fluid channels of the microcapillary network. The thin-film thermoelectric generator array is positioned between the cell sidewall and the thermal management separator. One end of the thin-film thermoelectric generator array is attached to the cell sidewall to form a hot end, and the other end is attached to the thermal management separator to form a cold end. The power output terminal of the thin-film thermoelectric generator array is electrically connected to the power input terminal of the solid-state electroosmotic micropump array. The rupture membrane is positioned on the sidewall of the microcapillary network, corresponding to the cell sidewall, and the internal channels of the microcapillary network are physically isolated from the external space of the cell through the rupture membrane.

[0024] A multi-parameter sensor array collects battery status data and environmental data. A data analysis and classification unit processes the data and determines the current thermal runaway risk level. The thermal runaway risk level is divided into Level 1, Level 2, and Level 3 warnings.

[0025] The Level 1 warning is triggered based on the temperature threshold of a single cell, the temperature rise threshold of the battery cluster, or the primary concentration threshold of a characteristic gas. Upon receiving the Level 1 warning signal, the linkage control subsystem outputs a DC signal to the solid-state electroosmotic micropump array with its built-in microfluidic pulse actuator. The solid-state electroosmotic micropump array drives the water-based extinguishing agent within the microcapillary network to circulate and exchange heat within the channels. Simultaneously, the linkage control subsystem controls the rotating positioning nozzle of the external macroscopic high-pressure pulse actuator to align with the battery cluster, spraying the extinguishing agent in a fine water mist mode.

[0026] The secondary warning is triggered based on a temperature change rate threshold, a characteristic gas secondary concentration threshold, or a pressure rise rate threshold. Upon receiving the secondary warning signal, the linkage control subsystem cuts off the power supply to the faulty battery. A temperature difference forms between the surface of the battery cell experiencing an abnormal temperature rise and the thermal management separator. The thin-film thermoelectric generator array generates and outputs a DC voltage based on this temperature difference. The DC voltage output by the thin-film thermoelectric generator array is input to the solid-state electroosmotic micropump array, which generates fluid dynamic pressure within the microcapillary network upon receiving the DC voltage. When the fluid dynamic pressure reaches a preset threshold, the rupture membrane ruptures, and the water-based fire extinguishing agent within the microcapillary network is injected into the battery cell. Simultaneously, the linkage control subsystem controls the pulse injection valve group of the external macroscopic high-pressure pulse actuator to intermittently spray fire extinguishing agent into the battery module.

[0027] The Level 3 warning is triggered by a flame signal, ambient temperature safety limits, or a lower explosive limit gas concentration ratio. Upon receiving the Level 3 warning signal, the linkage control subsystem activates audible and visual alarms and emergency broadcasts. The linkage control subsystem also controls the pulse injection valve assembly and rotary positioning nozzle of the external macroscopic high-pressure pulse actuator to initiate full-power continuous injection mode. Furthermore, the linkage control subsystem controls the explosion-proof inert gas injection system to inject inert gas into the redundant space within the battery pack casing.

[0028] The Level 1, Level 2, and Level 3 early warning actions executed by the linkage control subsystem are all subject to manual intervention or mode coverage control by the remote monitoring center.

[0029] A multi-parameter sensor array is arranged inside the battery pack and at the battery pack vents. The multi-parameter sensor array includes temperature sensors, gas sensors, pressure sensors, and voltage and current monitoring modules.

[0030] Temperature sensors are installed on the surface of individual battery cells and inside the battery pack. These sensors monitor the surface temperature of the individual battery cells and the ambient temperature of the battery pack. The temperature sensors are communicatively connected to the data analysis and grading unit, transmitting the collected temperature data to this unit.

[0031] Gas sensors are installed in the explosion-proof valve area of ​​individual battery cells and inside the battery pack. These sensors monitor carbon monoxide, hydrogen, and methane concentrations. The gas sensors are communicatively connected to the data analysis and classification unit, transmitting the collected gas concentration data to this unit.

[0032] A pressure sensor is located at the battery pack vent and is used to monitor pressure changes inside the battery pack. The pressure sensor is communicatively connected to the data analysis and classification unit, transmitting the collected pressure change data to the data analysis and classification unit.

[0033] The voltage and current monitoring module is located within the battery pack's main control board, and its detection terminals are electrically connected to the terminals of individual battery cells. The module is used to collect terminal voltage data and charge / discharge current data from individual battery cells.

[0034] The multi-parameter sensor array is connected to the data analysis and classification unit via a communication bus. Temperature sensors, gas sensors, pressure sensors, and voltage and current monitoring modules synchronously send multi-dimensional status monitoring data to the data analysis and classification unit via the communication bus.

[0035] The data analysis and classification unit incorporates a thermal runaway early warning algorithm. This unit receives monitoring data transmitted from a multi-parameter sensor array. It performs multi-dimensional parameter fusion analysis on the monitoring data and outputs a thermal runaway risk level signal. The thermal runaway risk level signal includes a Level 1 warning signal, a Level 2 warning signal, and a Level 3 warning signal.

[0036] The Level 1 warning signal is used to characterize a battery in a potential risk period. The data analysis and classification unit generates a Level 1 warning signal when at least one of the following conditions is met: the temperature sensor detects that the temperature of a single battery cell exceeds 50 degrees Celsius; the temperature sensor detects that the temperature rise within the battery cluster exceeds 5 degrees Celsius within 10 minutes; or the gas sensor detects that the concentration of a characteristic gas reaches the primary concentration threshold of the characteristic gas.

[0037] The secondary warning signal is used to characterize the battery during the thermal runaway triggering period. The data analysis and classification unit generates the secondary warning signal when at least one of the following conditions is met: the temperature sensor detects that the temperature change rate of the individual battery cell exceeds the set temperature change rate threshold; the gas sensor detects that the concentration of the characteristic gas reaches the secondary concentration threshold of the characteristic gas; the pressure sensor detects that the internal pressure rise rate of the battery pack exceeds the set pressure rise rate threshold.

[0038] The Level 3 warning signal is used to indicate that the battery is in a fire or explosion phase. The intelligent graded warning subsystem also includes an ultraviolet-infrared flame detector. The ultraviolet-infrared flame detector is located inside the battery pack and is communicatively connected to the data analysis and grading unit. The data analysis and grading unit generates a Level 3 warning signal when at least one of the following conditions is met: the ultraviolet-infrared flame detector detects an open flame and outputs a flame signal; the temperature sensor detects that the ambient temperature exceeds the safe limit; or the gas sensor detects that the gas concentration reaches the lower explosive limit threshold.

[0039] The data analysis and classification unit transmits the generated Level 1, Level 2, and Level 3 early warning signals to the linkage control subsystem via communication lines.

[0040] The built-in microfluidic pulse actuator includes: a thermal management baffle, a microcapillary network, a solid electroosmotic micropump array, and a water-based fire extinguishing agent.

[0041] Thermal management separators are placed between adjacent battery cells. The outer surface of the thermal management separator is attached to the sidewall of the battery cell, and the thermal management separator is used to conduct heat generated by the battery cell.

[0042] A microcapillary network is embedded inside the thermal management baffle. The microcapillary network forms a closed-loop fluid circulation channel inside the thermal management baffle. Water-based fire extinguishing agent is pre-filled inside the fluid circulation channel of the microcapillary network.

[0043] The solid-state electroosmotic micropump array is disposed within the fluid circulation channel of a microcapillary network. The solid-state electroosmotic micropump array includes a driving positive electrode and a driving negative electrode. The driving positive and negative electrodes are respectively arranged at both ends of the driving section within the microcapillary network, and are in physical contact with the water-based fire extinguishing agent. The control input terminals of the driving positive and negative electrodes are electrically connected to the linkage control subsystem, receiving DC signals output by the linkage control subsystem.

[0044] Upon receiving a primary warning signal, the linkage control subsystem outputs a low-voltage DC signal to the solid-state electroosmotic micropump array. Upon receiving the low-voltage DC signal, the solid-state electroosmotic micropump array establishes a DC electric field within the fluid circulation channels of the microcapillary network by driving the positive and negative electrodes.

[0045] A direct current electric field acts on the double layer formed at the interface between the inner wall of the microcapillary network and the water-based extinguishing agent. Under the influence of the direct current electric field, the double layer generates an electroosmotic flow effect. This electroosmotic flow effect drives the directional flow of the water-based extinguishing agent within the microcapillary network.

[0046] The water-based fire extinguishing agent continuously circulates within the closed-loop channels of the microcapillary network. The flowing water-based fire extinguishing agent absorbs heat conducted by the thermal management separator, carrying heat away from the concentrated areas on the surface of the individual battery cells. The water-based fire extinguishing agent reduces the surface temperature of the individual battery cells through forced convection heat transfer.

[0047] The extinguishing agent storage tank is used to store water-based extinguishing agents or anti-reignition gel. The fluid inlet of the high-pressure power unit is connected to the fluid outlet of the extinguishing agent storage tank via a pipeline. The high-pressure power unit is used to extract the water-based extinguishing agent or anti-reignition gel from the extinguishing agent storage tank and provide high-pressure delivery power to downstream pipelines. The fluid inlet of the pulse jet valve assembly is connected to the fluid outlet of the high-pressure power unit via a pipeline. The fluid outlet of the pulse jet valve assembly is connected to the fluid inlet of the rotary positioning nozzle via a high-pressure pipeline.

[0048] The rotary positioning nozzle is installed on the outside of the battery device, either above or to the side front. The rotary positioning nozzle comprises a stepper motor drive mechanism, a mode switching mechanism, and a nozzle. The control input of the stepper motor drive mechanism is communicatively connected to the linkage control subsystem, and the power output of the stepper motor drive mechanism is mechanically connected to the nozzle. The control input of the mode switching mechanism is also communicatively connected to the linkage control subsystem, and the mode switching mechanism controls the nozzle to switch between a fine water mist mode and a water jet mode.

[0049] Upon receiving a Level 1 warning signal, the linkage control subsystem activates the audible and visual alarm device and sends notification data to the monitoring center. Simultaneously, the linkage control subsystem outputs angle control signals to the stepper motor drive mechanism within the rotary positioning nozzle, outputs mode control signals to the mode switching mechanism, and controls the high-pressure power unit and pulse jet valve assembly to start operation.

[0050] After receiving the angle control signal, the stepper motor drive mechanism drives the nozzle to adjust its horizontal and vertical angles. The nozzle's spatial orientation is aligned with the battery cluster experiencing abnormal temperature rise. After receiving the mode control signal, the mode switching mechanism switches the nozzle's internal flow channel to fine water mist mode.

[0051] The water-based extinguishing agent or anti-reignition gel inside the extinguishing agent storage tank is pressurized by the high-pressure power unit and then delivered to the rotary positioning nozzle via a pulse jet valve assembly. The pressurized water-based extinguishing agent or anti-reignition gel is then sprayed as a fine water mist onto the surface of the battery cluster and its surrounding area through the nozzle. The fine water mist absorbs the ambient heat of the battery cluster and dilutes the flammable gases accumulated in the air. The external environmental cooling action of the external macroscopic high-pressure pulse actuator is synchronized with the internal circulating heat exchange action of the built-in microfluidic pulse actuator.

[0052] A thin-film thermoelectric generator array is arranged between the sidewall of the battery cell and the thermal management separator. The thin-film thermoelectric generator array includes a hot end face and a cold end face, wherein the hot end face of the thin-film thermoelectric generator array is attached to the sidewall of the battery cell, and the cold end face of the thin-film thermoelectric generator array is attached to the outer sidewall of the thermal management separator.

[0053] The power output terminal of the thin-film thermoelectric generator array is electrically connected to the power input terminal of the solid-state electroosmotic micropump array, and a unidirectional isolation module is connected in series in the power supply circuit between the power output terminal and the power input terminal. The positive output terminal of the thin-film thermoelectric generator array is connected to the driving positive electrode of the solid-state electroosmotic micropump array through the unidirectional isolation module, and the negative output terminal of the thin-film thermoelectric generator array is connected to the driving negative electrode of the solid-state electroosmotic micropump array. The unidirectional isolation module is used to block the reverse feed of the external low-voltage DC power supply circuit to the thin-film thermoelectric generator array.

[0054] The rupture membrane is installed on the sidewall of the channel corresponding to the position of the battery cell in the microcapillary network. The rupture membrane blocks the internal channel of the microcapillary network, physically isolating the water-based fire extinguishing agent inside the microcapillary network from the external space of the battery cell, and the rupture membrane has a preset physical yield pressure threshold.

[0055] When the multi-parameter sensor array detects a sharp increase in the rate of temperature change or an abnormal surge in the internal pressure of the battery pack, the linkage control subsystem generates a secondary warning signal. Upon receiving the secondary warning signal, the linkage control subsystem cuts off the power supply circuit to the faulty battery cluster and simultaneously disconnects the external low-voltage DC power supply circuit to the solid-state electroosmotic micropump array.

[0056] When an abnormality occurs, the surface temperature of the individual battery cell rises sharply, and the heat from the cell surface is directly conducted to the hot end of the thin-film thermoelectric generator array. The thermal management separator absorbs the heat and maintains a relatively low temperature at the cold end of the thin-film thermoelectric generator array, thereby creating a physical temperature difference between the hot and cold ends of the array.

[0057] The thin-film thermoelectric generator array converts physical temperature differences into transient high-voltage direct current based on the Seebeck effect. The transient high-voltage direct current output from the thin-film thermoelectric generator array is transmitted to the driving positive and driving negative electrodes of the solid-state electroosmotic micropump array. The driving positive and driving negative electrodes establish a transient high-voltage electric field within the microcapillary network.

[0058] A transient high-voltage electric field acts on the electric double layer at the interface between the inner wall of the microcapillary network and the water-based fire extinguishing agent. Driven by the electric field, the water-based fire extinguishing agent experiences localized high-speed fluid displacement. This high-speed fluid displacement creates hydrodynamic pressure within the locally enclosed channels of the microcapillary network. The increased surface temperature of the individual battery cells leads to an increase in the transient high-voltage direct current output from the thin-film thermoelectric generator array, and the hydrodynamic pressure increases positively correlated with the increase in transient high-voltage direct current.

[0059] When the fluid dynamic pressure exceeds the physical yield pressure threshold of the ruptured membrane, structural rupture occurs. The water-based extinguishing agent within the microcapillary network penetrates the ruptured membrane and is ejected as a transient pulse jet onto the surface and internal regions of the battery cell. The water-based extinguishing agent absorbs heat from the heat source and inhibits the chemical reaction chain within the battery cell.

[0060] The pulse jet valve assembly includes a high-speed solenoid valve. The control input of the high-speed solenoid valve is communicatively connected to the linkage control subsystem. The fluid output of the high-pressure power unit is connected to the fluid input of the pulse jet valve assembly via a high-pressure pipeline. The fluid output of the pulse jet valve assembly is connected to the fluid input of the rotary positioning nozzle via a high-pressure pipeline.

[0061] When the data analysis and grading unit outputs a level-two warning signal, the linkage control subsystem automatically cuts off the power supply circuit to the faulty battery cluster. The linkage control subsystem also outputs a position control signal to the stepper motor drive mechanism inside the rotary positioning nozzle. Upon receiving the position control signal, the stepper motor drive mechanism drives the nozzle to adjust its spatial orientation and align it with the battery module that triggered the level-two warning signal.

[0062] The linkage control subsystem outputs pulse control signals to the pulse injection valve assembly. The high-speed solenoid valve within the pulse injection valve assembly receives the pulse control signals and executes instantaneous start-stop actions on the fluid passage. The linkage control subsystem controls the pulse injection valve assembly to enter directional pulse injection mode by adjusting the pulse frequency and duty cycle of the output signal.

[0063] The high-pressure water-based extinguishing agent or anti-reignition gel output from the high-pressure power unit flows through the pulse jet valve assembly. A high-speed solenoid valve inside the pulse jet valve assembly interrupts the continuous flow of high-pressure water-based extinguishing agent or anti-reignition gel, converting it into intermittent high-pressure jets. These intermittent high-pressure jets are then directed through a rotating positioning nozzle to the heat dissipation gaps and surface areas of the battery module. The pulse interval of the directional pulse jet action is less than or equal to 3 seconds.

[0064] High-pressure water-based fire extinguishing agents or anti-reignition gels directly cool the heat source points of the battery module, inhibiting the chemical reaction chain inside the battery module. The external directional pulse jet action of the external macro high-pressure pulse actuator is executed synchronously with the internal jet action of the built-in microfluidic pulse actuator, completing the internal and external coordinated handling of the secondary warning stage.

[0065] When the data analysis and grading unit outputs a level-three early warning signal, the linkage control subsystem activates the audible and visual alarm device and emergency broadcast equipment connected to the communication network.

[0066] The linkage control subsystem outputs a normally open control signal to the pulse jet valve assembly. The high-speed solenoid valve inside the pulse jet valve assembly receives the normally open control signal and remains in the conducting state under the action of the normally open control signal. The pulse jet valve assembly stops the fluid cut-off action, and the external macroscopic high-pressure pulse actuator enters the full-power continuous injection mode.

[0067] The linkage control subsystem outputs scanning control signals and fluid pattern control signals to the rotary positioning nozzle. Upon receiving the fluid pattern control signal, the mode switching mechanism inside the rotary positioning nozzle switches the nozzle's internal flow channel to water jet mode. Upon receiving the scanning control signal, the stepper motor drive mechanism inside the rotary positioning nozzle drives the nozzle to perform reciprocating mechanical scanning motion within a set horizontal and vertical angle range.

[0068] A fire extinguishing agent storage tank with a volume of 50 liters or more provides sufficient fluid medium for the full-power continuous spray mode. The high-pressure power unit draws water-based fire extinguishing agent or anti-reignition gel from inside the fire extinguishing agent storage tank and outputs high-pressure fluid to the downstream stage through pipelines at an operating pressure of 1.2 MPa or more.

[0069] High-pressure water-based extinguishing agent or anti-reignition gel flows through a pulse jet valve assembly that remains open and enters the rotary nozzle along the high-pressure pipeline. The water-based extinguishing agent or anti-reignition gel is then sprayed into the target area through nozzles inside the rotary nozzle, forming a water jet pattern that penetrates the flame after exiting the nozzle.

[0070] The spray distance of the water-based extinguishing agent or anti-reignition gel in water jet form is greater than or equal to 10 meters. The reciprocating mechanical scanning motion of the rotating positioning nozzle allows the water-based extinguishing agent or anti-reignition gel to cover a large area of ​​the burning battery cluster and adjacent battery cluster areas. The high flow rate of water-based extinguishing agent or anti-reignition gel achieves full coverage fire extinguishing and cooling.

[0071] This invention provides a lithium battery system for underground coal mines with thermal runaway protection, which may further include: an explosion-proof inert gas injection system. The explosion-proof inert gas injection system includes an inert gas storage tank, an electrically controlled release valve, a gas injection pipeline, and an explosion-proof pressure relief valve installed on the battery pack casing.

[0072] An inert gas storage tank is located on the outer surface of the battery pack casing and is used to pre-store high-pressure inert gas. The gas outlet of the inert gas storage tank is connected to the gas inlet of the electrically controlled release valve via a high-pressure pipeline. The gas outlet of the electrically controlled release valve is connected to the inlet of the gas injection pipeline. The outlet of the gas injection pipeline passes through the battery pack casing and extends into the redundant space inside the battery pack casing. An explosion-proof pressure relief valve connects the redundant space inside the battery pack casing to the external environment.

[0073] The electrical control terminal of the electrically controlled release valve is communicatively connected to the linkage control subsystem. The linkage control subsystem is used to control the opening and closing status of the internal passage of the electrically controlled release valve.

[0074] When the data analysis and grading unit outputs a level-three warning signal, the linkage control subsystem sends an opening control command to the electrically controlled release valve, controlling the valve to open the gas release channel. The high-pressure inert gas inside the inert gas storage tank is released through the opened electrically controlled release valve and transported to the inside of the battery pack casing along the gas injection pipeline.

[0075] High-pressure inert gas fills the redundant space inside the battery pack casing, and the air inside the redundant space is discharged to the external environment through the explosion-proof pressure relief valve through gas displacement.

[0076] High-pressure inert gas reduces the overall oxygen concentration inside the battery pack casing, creating an inert gas protective environment. This inert gas protective environment blocks the path of open flame to spread to adjacent battery cells and the external environment. The inert gas filling action of the explosion-proof inert gas injection system is synchronized with the full-coverage continuous injection action of the external macroscopic high-pressure pulse actuator, jointly achieving global physical isolation and explosion suppression during a fire or explosion.

[0077] Example 1: The trackless rubber-wheeled vehicle is equipped with an onboard battery pack and is parked at the charging station in the underground charging chamber of a coal mine for charging operations. A multi-parameter sensor array of the intelligent graded early warning subsystem is arranged inside the onboard battery pack, and the multi-parameter sensor array establishes a data communication connection with the linkage control subsystem through the communication terminals of the charging connector. An integrated microfluidic pulse actuator is embedded between the individual battery cells inside the onboard battery pack.

[0078] The linkage control subsystem is located in the explosion-proof control cabinet of the charging chamber. The extinguishing agent storage tank of the external macroscopic high-voltage pulse actuator and the high-voltage power unit are located in the equipment room of the charging chamber, with the extinguishing agent storage tank having a volume of 60 liters. The high-voltage power unit uses a plunger pump driven by an explosion-proof motor. A rotary positioning nozzle is installed on the top of the chamber directly above the charging station, and its spray range covers the trackless rubber-wheeled vehicle parked at the charging station. The inert gas storage tank of the explosion-proof inert gas injection system is fixed to the vehicle's frame, and the gas output end of the inert gas storage tank is connected via pipeline to the redundant space inside the vehicle's battery pack casing.

[0079] During the charging process of the trackless rubber-wheeled vehicle, a multi-parameter sensor array collects multi-dimensional status data of the vehicle's battery pack in real time. When the data analysis and grading unit determines that the vehicle's battery pack meets the first-level warning conditions, the linkage control subsystem outputs a low-voltage DC signal to the built-in microfluidic pulse execution unit. The solid-state electroosmotic micro-pump array inside the built-in microfluidic pulse execution unit drives the water-based fire extinguishing agent to circulate within the thermal management partition, providing forced convective heat transfer cooling to the battery cells experiencing abnormal temperatures. Simultaneously, the linkage control subsystem controls the rotating positioning nozzle to aim at the vehicle's battery pack area and sprays the water-based fire extinguishing agent in a fine water mist mode, reducing the ambient temperature of the external chamber of the vehicle's battery pack.

[0080] When the data analysis and grading unit determines that the vehicle battery pack meets the level 2 warning conditions, the linkage control subsystem cuts off the charging power supply circuit of the trackless rubber-wheeled vehicle. The rapidly rising temperature of the individual battery cells creates a physical temperature difference across the thin-film thermoelectric generator array, which outputs transient high-voltage direct current based on this temperature difference. This transient high-voltage direct current drives the solid-state electroosmotic micropump array to break through the ruptured membrane on the sidewall of the microcapillary network, allowing water-based fire extinguishing agent to be directly injected into the abnormally heated battery cells in the form of transient pulse jets. Simultaneously, the linkage control subsystem activates the pulse jet valve group of the external macroscopic high-voltage pulse actuator, rotating the positioning nozzle to directionally spray high-voltage intermittent jets into the heat dissipation gaps of the vehicle battery pack's outer shell. The external macroscopic high-voltage pulse actuator and the internal microfluidic pulse actuator execute the spraying action synchronously, achieving a cascaded and coordinated effect of internal water hammer breakdown and external gap coverage.

[0081] When the data analysis and grading unit determines that the vehicle battery pack meets the level three warning conditions, the linkage control subsystem controls the pulse jet valve group to switch to the normally open state. The rotary positioning nozzle switches to water jet mode and performs reciprocating mechanical scanning motion above the trackless rubber-tired vehicle. A 60-liter fire extinguishing agent storage tank provides the system with water-based fire extinguishing agent. The continuous high-pressure water jet output by the rotary positioning nozzle provides full coverage fire extinguishing for the trackless rubber-tired vehicle and surrounding area. Simultaneously, the explosion-proof inert gas injection system injects high-pressure inert gas into the vehicle battery pack. The high-pressure inert gas, through gas displacement, discharges the air inside the vehicle battery pack through the explosion-proof pressure relief port, establishing an inert gas protective environment inside the vehicle battery pack.

[0082] Example 2: The battery compartment of the large-scale underground energy storage power station in the coal mine is equipped with multiple parallel battery clusters, each cluster consisting of multiple stacked battery packs. A multi-parameter sensor array of the intelligent hierarchical early warning subsystem is distributedly installed inside each battery pack, and the multi-parameter sensor array establishes a data communication connection with the linkage control subsystem via an industrial fieldbus. Built-in microfluidic pulse actuators are modularly integrated between the individual battery cells within each battery pack.

[0083] The linkage control subsystem communicates with the energy management system of the battery compartment of the large energy storage power station and the circuit breaker of the energy storage converter. The high-voltage power unit of the external macro high-voltage pulse actuator and the fire extinguishing agent storage tank are centrally located in the equipment room outside the battery compartment. The fluid output end of the high-voltage power unit is connected to multiple pulse jet valve groups distributed inside the battery compartment through the high-voltage main pipeline network. The multiple pulse jet valve groups are connected to multiple rotary positioning nozzles arranged in an array above the battery compartment inspection channel through branch pipelines. The spray distance of the rotary positioning nozzles is greater than or equal to 10 meters, achieving full coverage of the bottom battery cluster. The inert gas storage tank of the explosion-proof inert gas injection system is centrally located in the equipment room. The inert gas storage tank is connected to multiple electrically controlled release valves through the gas main pipe. The multiple electrically controlled release valves are connected to the redundant space inside each battery pack through gas injection pipelines.

[0084] During the operation of the battery compartment in a large-scale energy storage power station, a multi-parameter sensor array collects status data in real time. When the data analysis and grading unit determines that a battery pack meets the first-level warning conditions, the linkage control subsystem sends a control command to the built-in microfluidic pulse actuator within the corresponding battery pack. The solid-state electroosmotic micropump array inside the built-in microfluidic pulse actuator drives the water-based fire extinguishing agent to perform low-pressure circulating cooling. At the same time, the linkage control subsystem controls the rotating positioning nozzles above the corresponding area to switch to fine water mist mode, spraying fine water mist onto the space where the battery cluster with abnormal temperature rise is located, thereby reducing the local ambient temperature.

[0085] When the data analysis and grading unit determines that the battery pack meets the level 2 warning conditions, the linkage control subsystem sends an isolation command to the energy management system. The energy management system then disconnects the circuit breaker of the energy storage converter for the corresponding battery cluster to achieve electrical isolation. The physical temperature difference between the battery cell experiencing abnormal temperature rise and the thermal management separator drives the thin-film thermoelectric generator array to generate transient high-voltage direct current. Under the action of the transient high-voltage direct current, the solid-state electroosmotic micro-pump array generates local hydrodynamic pressure, which breaks through the ruptured membrane and injects water-based fire extinguishing agent into the battery cell in the form of a transient pulse jet. Simultaneously, the linkage control subsystem controls the pulse jet valve group in the corresponding area to start, and the rotating positioning nozzles directionally spray high-pressure intermittent jets into the structural gaps of the battery cluster experiencing abnormal temperature rise, achieving coordinated internal and external physical suppression.

[0086] When the data analysis and grading unit determines that the battery pack meets the level three warning conditions, the linkage control subsystem activates a global audible and visual alarm in the battery compartment. The external macroscopic high-pressure pulse actuator enters full-power continuous spray mode, and multiple rotating positioning nozzles perform cross-scanning actions in water jet mode, using long-distance water jets to achieve full-coverage continuous spraying of the multi-cluster parallel area. Simultaneously, the linkage control subsystem controls the opening of the corresponding area's electrically controlled release valve, and the explosion-proof inert gas injection system injects high-pressure inert gas into the battery pack that triggered the warning and adjacent battery packs through the gas injection pipeline. The high-pressure inert gas replaces the air in the redundant space of the battery pack, establishing a cross-pack-level inert gas protection environment between the densely stacked battery clusters, blocking the heat spread path of the fire.

[0087] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A lithium battery system for underground coal mines with thermal runaway protection, characterized in that, It includes an intelligent graded early warning subsystem, a linkage control subsystem, and a high-voltage pulse fire extinguishing execution subsystem; The intelligent graded early warning subsystem is used to monitor the battery's status parameters in real time and output a thermal runaway risk level signal; The linkage control subsystem is connected to the intelligent hierarchical early warning subsystem, receives the thermal runaway risk level signal and generates control commands; The high-voltage pulse fire extinguishing execution subsystem is connected to the linkage control subsystem and receives the control command to execute fire extinguishing or cooling actions. The high-pressure pulse fire extinguishing execution subsystem includes an external macro high-pressure pulse execution unit and an internal microfluidic pulse execution unit; The built-in microfluidic pulse execution unit includes a thermal management partition, a microcapillary network, a solid electroosmotic micropump array, a water-based fire extinguishing agent, a thin-film thermoelectric generator array, and a rupture membrane. The thermal management partition is disposed between individual battery cells. The microcapillary network is embedded inside the thermal management partition. The solid electroosmotic micropump array is disposed within the fluid circulation channel of the microcapillary network. The water-based fire extinguishing agent is filled inside the microcapillary network. The thin-film thermoelectric generator array is disposed between the sidewall of the individual battery cell and the thermal management partition. The rupture membrane is disposed on the channel sidewall of the microcapillary network corresponding to the sidewall of the individual battery cell, physically isolating the water-based fire extinguishing agent inside the microcapillary network from the external space of the individual battery cell.

2. A coal mine underground lithium battery system with thermal runaway protection function according to claim 1, characterized in that, The thin-film thermoelectric generator array includes a hot end face and a cold end face. The hot end face is attached to the side wall of the battery cell, and the cold end face is attached to the outer side wall of the thermal management separator. The power output terminal of the thin-film thermoelectric generator array is electrically connected to the power input terminal of the solid-state electroosmotic micropump array, and a unidirectional isolation module is connected in series in the power supply circuit between the power output terminal and the power input terminal; the unidirectional isolation module is used to block the external low-voltage DC power supply circuit from feeding back power to the thin-film thermoelectric generator array. The solid electroosmotic micropump array includes a driving positive electrode and a driving negative electrode, which are respectively arranged at both ends of the driving section in the microcapillary network and in physical contact with the water-based fire extinguishing agent.

3. A coal mine underground lithium battery system with thermal runaway protection function according to claim 2, characterized in that, The thermal runaway risk level signal includes a level two early warning signal; The linkage control subsystem is configured to: upon receiving the secondary warning signal, cut off the power supply circuit of the battery cluster where the battery cell with abnormal temperature rise is located, and simultaneously disconnect the external low-voltage DC power supply circuit of the solid electroosmotic micropump array. A physical temperature difference is formed between the surface of the battery cell with abnormal temperature rise and the thermal management separator. The thin-film thermoelectric generator array converts the physical temperature difference into transient high-voltage direct current. The transient high-voltage direct current output by the thin-film thermoelectric generator array is transmitted to the driving positive electrode and the driving negative electrode, establishing a transient high-voltage electric field inside the microcapillary network. This drives the water-based fire extinguishing agent to generate local high-speed fluid displacement, forming hydrodynamic pressure. When the hydrodynamic pressure exceeds the physical yield pressure threshold of the ruptured membrane, the ruptured membrane ruptures, and the water-based fire extinguishing agent is sprayed into the surface and internal area of ​​the battery cell in the form of a transient pulse jet.

4. A coal mine underground lithium battery system with thermal runaway protection function according to claim 2, characterized in that, The thermal runaway risk level signal includes a level one early warning signal; the fluid circulation channel inside the microcapillary network is a closed-loop structure; The linkage control subsystem is configured to: upon receiving the first-level warning signal, output a low-voltage DC signal to the solid-state electroosmotic micropump array; the solid-state electroosmotic micropump array establishes a DC electric field in the fluid circulation channel, and drives the water-based fire extinguishing agent to continuously circulate in the closed-loop fluid circulation channel through the electroosmotic flow effect, thereby carrying away the heat from the surface of the battery cell from the enrichment area for forced convection heat transfer.

5. A coal mine underground lithium battery system with thermal runaway protection function according to claim 1, characterized in that, The external macro high-pressure pulse actuator includes an extinguishing agent storage tank, a high-pressure power unit, a pulse injection valve assembly, and a rotary positioning nozzle; The extinguishing agent storage tank is used to store water-based extinguishing agents or anti-reignition gel; the fluid input end of the high-pressure power unit is connected to the fluid output end of the extinguishing agent storage tank through a pipeline; the fluid input end of the pulse jet valve assembly is connected to the fluid output end of the high-pressure power unit through a pipeline; the fluid output end of the pulse jet valve assembly is connected to the fluid input end of the rotary positioning nozzle through a high-pressure pipeline. The rotary positioning nozzle includes a stepper motor drive mechanism, a mode switching mechanism, and a nozzle. The power output end of the stepper motor drive mechanism is mechanically connected to the nozzle; the mode switching mechanism controls the nozzle to switch the fluid pattern between fine water mist mode and water jet mode.

6. A coal mine underground lithium battery system with thermal runaway protection function according to claim 5, characterized in that, The pulse jet valve assembly includes a high-speed solenoid valve; The linkage control subsystem is configured to: when a secondary warning signal is received, output a position control signal to the stepper motor drive mechanism to drive the nozzle to adjust its spatial posture and align it with the target area where the battery module or battery cluster that has experienced abnormal temperature rise is located. The linkage control subsystem outputs a pulse control signal to the pulse jet valve group, controlling the high-speed solenoid valve to perform instantaneous start and stop actions of the fluid channel, cutting off the continuous high-pressure water-based fire extinguishing agent or anti-reignition gel output by the high-pressure power unit and converting it into an intermittent high-pressure jet, which is then directed to the heat dissipation gaps and surface areas of the target battery area, and is executed synchronously with the internal jet action of the built-in microfluidic pulse execution unit.

7. A coal mine underground lithium battery system with thermal runaway protection function according to claim 5, characterized in that, The risk level signal for thermal runaway includes three levels of warning signals; The linkage control subsystem is configured to: upon receiving the level 3 warning signal, output a normally open control signal to the pulse injection valve group, control the pulse injection valve group to remain in the conducting state and enter the full-speed continuous injection mode; The linkage control subsystem outputs a fluid pattern control signal to the mode switching mechanism to switch the internal flow channel of the nozzle to the water jet mode; the linkage control subsystem outputs a scanning control signal to the stepper motor drive mechanism to drive the nozzle to perform reciprocating mechanical scanning motion within a set horizontal angle range and a pitch angle range to implement full-coverage continuous spraying.

8. A coal mine underground lithium battery system with thermal runaway protection function according to claim 1, characterized in that, Also includes: An explosion-proof inert gas injection system; the explosion-proof inert gas injection system includes an inert gas storage tank, an electrically controlled release valve, a gas injection pipeline, and an explosion-proof pressure relief valve installed on the battery pack casing; The gas output end of the inert gas storage tank is connected to the gas input end of the electrically controlled release valve via a high-pressure pipeline; the gas output end of the electrically controlled release valve is connected to the inlet end of the gas injection pipeline; the outlet end of the gas injection pipeline passes through the battery pack shell and extends into the redundant space inside the battery pack shell; the explosion-proof pressure relief valve connects the redundant space inside the battery pack shell with the external environment. The linkage control subsystem is configured to: upon receiving a level 3 warning signal, output an opening control command to the electronically controlled release valve, transport the high-pressure inert gas inside the inert gas storage tank to the redundant space inside the battery pack casing, and discharge the air inside the redundant space through the explosion-proof pressure relief valve via gas displacement, thereby forming an inert gas protective environment.

9. A coal mine underground lithium battery system with thermal runaway protection function according to claim 1, characterized in that, The intelligent hierarchical early warning subsystem includes a multi-parameter sensor array and a data analysis and hierarchical unit; The multi-parameter sensor array is arranged inside the battery pack and at the battery pack ventilation opening; the multi-parameter sensor array includes a temperature sensor, a gas sensor, a pressure sensor, and a voltage and current monitoring module; The data analysis and classification unit is communicatively connected to the multi-parameter sensor array; the temperature sensor is used to monitor the surface temperature of the individual battery cells and the ambient temperature of the battery pack; the gas sensor is used to monitor the concentrations of carbon monoxide, hydrogen, and methane; and the pressure sensor is used to monitor the pressure changes inside the battery pack. The voltage and current monitoring module is used to collect terminal voltage data of individual battery cells and charging and discharging current data.

10. A coal mine underground lithium battery system with thermal runaway protection function according to claim 9, characterized in that, The data analysis and hierarchical unit embeds a thermal runaway early warning algorithm, which is used to perform multi-dimensional parameter fusion analysis on the monitoring data; The data analysis and classification unit is configured to generate a secondary warning signal when at least one of the following conditions is met: the temperature sensor detects that the temperature change rate of the battery cell exceeds a set temperature change rate threshold; the gas sensor detects that the concentration of the characteristic gas reaches a secondary concentration threshold for the characteristic gas; or the pressure sensor detects that the pressure rise rate inside the battery pack exceeds a set pressure rise rate threshold.

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