A high-power charging pile thermal runaway monitoring method and protection system thereof

Abstract

The application discloses a high-power charging pile thermal runaway monitoring method and a protection system thereof, relates to the technical field of high-power energy supplementing infrastructure for new energy vehicles and extreme thermal physical safety control, and aims to solve the technical defects of lagging thermal runaway monitoring and passive protection of the existing high-power charging pile. The monitoring method discloses the single dependence on the terminal temperature lagging representation, constructs an early microcosmic evolution detection system of multi-physical field coupling, realizes early and accurate identification of thermal runaway precursors through the synergistic detection of three dimensions of electrical frequency domain micro stress detection, cooling medium micro boiling acoustic detection and interface escaping gas concentration feedforward detection, and combines multi-dimensional state fusion threshold determination. The protection system corresponds to the above monitoring method, is composed of a hybrid type ultra-fast breaking module, an active phase change flooding fire extinguishing module, a gun end forced separation module and a comprehensive decision-making master control hub, and realizes graded active protection in different stages of thermal runaway.

Description

Technical Field

[0001] This invention relates to the field of high-power charging infrastructure for new energy vehicles and extreme thermophysical safety control technology, specifically a method for monitoring thermal runaway of high-power charging piles and its protection system. Background Technology

[0002] With the soaring penetration rate of new energy vehicles globally and consumers' pursuit of charging efficiency comparable to that of gasoline vehicles, DC fast charging technology is undergoing rapid development from "high-voltage fast charging" to "ultra-high-power liquid-cooled supercharging". Currently, high-performance electric vehicles based on 800-volt or even 1000-volt electrical architectures have easily broken through the 500-ampere or even 600-ampere mark in peak charging current.

[0003] Under such high energy transmission density, the entire charging pile system—especially the "charging gun and vehicle socket interface," which serves as the end point for human-machine interaction and power handshake—is undergoing extreme electrical, mechanical, and thermophysical stress tests. Traditional air-cooled cables can no longer suppress the temperature rise caused by Joule heating generated by the product of the square of the current and the resistance; therefore, liquid-cooled charging guns and liquid-cooled cables have become standard configurations for supercharging systems.

[0004] However, through extensive on-site engineering maintenance and accident reverse analysis, the industry has discovered that the existing "liquid cooling and passive temperature monitoring" system has serious and fatal flaws in its underlying logic. These flaws are the root cause of frequent overheating of charging stations and even ignition of vehicle batteries. First, traditional thermistor monitoring systems suffer from severe thermal hysteresis. Existing charging guns typically monitor temperature by attaching or encapsulating an NTC probe at the tail of the metal terminal. However, the presence of potting compound, insulating thermal pads, and other materials between the terminal and the NTC forms a large low-pass filter network of thermal capacity and thermal resistance. When the contact resistance of the terminal surface deteriorates instantaneously due to wear, the heat generated explodes nonlinearly within seconds (local temperatures may instantly exceed 200 degrees Celsius, causing carbonization of plastic parts). The NTC probe, separated by the insulating layer, often takes tens of seconds to detect a significant temperature rise. This huge time lag means that by the time the monitoring system makes a decision to "reduce power" or "shut down," the insulating material at the terminal has already reached its flash point, and thermal runaway is already in an irreversible stage.

[0005] Secondly, there's the thermal masking effect of liquid cooling systems. High-flow-rate coolant (e.g., 5 to 10 liters per minute) not only removes normal Joule heat but also masks early, localized faults. Minor abnormal heat generation is quickly carried away and suppressed by strong liquid convection, making the system unaware of early contact degradation. Faults are only revealed when the local heat flux density completely exceeds the heat transfer limit of the liquid cooling system, but this usually means disaster has already occurred.

[0006] Finally, there are the limitations of passive protection. When existing charging stations detect high temperatures, their only protective action is to command the contactor to "disconnect the circuit." However, for charging heads that have already caught fire or are undergoing violent oxidation-reduction reactions internally (with carbonized conductive pathways already formed), simply cutting off the power is futile. The remaining enormous heat cannot dissipate, and the polycarbonate or cross-linked polyethylene casing will continue to burn, potentially spreading along the socket to the vehicle's battery pack, leading to a major accident where the entire vehicle is destroyed by fire.

[0007] To address this, a method for monitoring thermal runaway in high-power charging piles and its protection system are proposed. Summary of the Invention

[0008] The purpose of this invention is to provide a method for monitoring thermal runaway in high-power charging piles and a corresponding protection system. This aims to address one of the problems existing in the prior art.

[0009] Firstly, to address the aforementioned technical problems, this application adopts a technical solution: a method for monitoring thermal runaway in high-power charging piles. This method abandons the singular reliance on terminal temperature hysteresis characterization and achieves this by constructing a multi-physics field coupled early microscopic evolution detection system. Specifically, it includes the following mutually verifying and synergistic steps: Electrical frequency domain micro-stress detection: Under the background of continuous output of large current from DC charging bus, the power converter inside the charging pile actively injects a micro-volt high-frequency sinusoidal disturbance signal containing a specific frequency broadband, and simultaneously extracts the high-frequency response current at the corresponding frequency. The real-time broadband AC impedance spectrum between the charging gun terminal and the vehicle socket is calculated by fast Fourier transform. Acoustic detection of micro-boiling of cooling medium: A high-frequency acoustic emission sensor array is deployed on the liquid cooling circulation loop of the charging pile to capture acoustic signals inside the liquid cooling cable and the water jacket of the charging gun head in real time. Multidimensional state fusion and threshold determination: Extract the capacitive resistance component offset rate in the broadband AC impedance spectrum and the ultrasonic pulse count value in the acoustic signal caused by the rupture of bubbles in the local film boiling of the coolant; when the rising slope of the capacitive resistance component offset rate and the ultrasonic pulse count value both exceed the dynamic safety envelope within a set time window, it is determined that the charging system has contact degradation and thermal runaway precursors, and a graded protection action is triggered.

[0010] In one possible implementation, in the electrical frequency domain micro-stress detection step, to avoid interference with the main DC charging process, the frequency range of the microvolt-level high-frequency sinusoidal disturbance signal is limited to between 150 kHz and 500 kHz. This frequency band signal utilizes the parasitic RC network characteristics formed by the DC bus distributed capacitance and contact resistance to specifically extract the microscopic contact resistance drastic changes caused by the oxide layer or wear on the terminal surface. Moreover, this impedance extraction process is naturally immune to low-frequency fluctuations of the large DC current of the bus.

[0011] In one possible implementation, the physical logic of the acoustic detection step for micro-boiling of the cooling medium is as follows: when poor contact at the charging gun terminal causes rapid heat generation, due to the severe thermal resistance delay caused by the NTC temperature sensor being encapsulated in potting compound, the extremely high local heat flux on the terminal surface will first cause the liquid cooling medium flowing along the wall to break through the saturated vapor pressure and generate microbubbles; by monitoring the transient acoustic emission energy bursts generated by these microbubbles when they condense and collapse in the subcooled fluid, with frequencies in the range of 100 kHz to 300 kHz, zero-delay sensing of temperature changes can be achieved.

[0012] In one possible implementation, the method further includes a feedforward detection step for the concentration of gas escaping from the interface: embedding a trace characteristic gas array sensor based on MEMS technology inside the mechanical locking cavity of the charging gun head, for capturing the concentration of trace carbon monoxide and volatile organic compounds released during the initial stage of thermal decomposition of cross-linked polyethylene or polycarbonate before the insulating material reaches its flash point; and using the first derivative of this concentration as the highest priority trigger parameter for multidimensional state fusion determination.

[0013] Secondly, to solve the above-mentioned technical problems, another technical solution adopted in this application is: a high-power charging pile protection system for implementing the monitoring method, comprising the following modules that work together: The hybrid high-speed interruption module, connected in series in the DC charging output main circuit, consists of a solid-state DC circuit breaker and a gunpowder-propelled fast mechanical disconnect switch connected in parallel. It is used to interrupt fault currents of up to thousands of amperes in microseconds and provide physical insulation breakpoints. An active phase change flooding fire extinguishing module includes an independent energy storage pressure tank connected in parallel to a liquid cooling circulation loop. The energy storage pressure tank is pre-filled with high-pressure inert driving gas and perfluorohexanone phase change fire extinguishing medium. The gun-end forced disengagement module is integrated into the connection between the charging gun body and the charging pile cable or into the gun head mechanical locking structure. The integrated decision-making control center connects and controls all the above modules. When the monitoring method determines that thermal runaway is in an irreversible outbreak stage, it not only triggers the hybrid rapid interruption module to cut off the power supply, but also shuts down the normal liquid cooling circulation pump and opens the servo solenoid valve to instantly pressurize the perfluorohexanone in the energy storage pressure tank into the liquid cooling cable and the nozzle water jacket. It uses its extremely low boiling point to vaporize and absorb heat for forced physical cooling and to block combustion.

[0014] In one possible implementation, the active phase change flooding fire extinguishing module is designed with a bypass pressure relief and discharge channel in the pipeline topology; when perfluorohexanone is violently vaporized in the high-temperature zone of the nozzle, causing the pressure inside the pipeline to rise sharply to the explosion critical value, the pressure relief valve is passively opened, and the vaporized perfluorohexanone carrying a large amount of latent heat is discharged into the atmosphere. At the same time, the energy storage pressure tank continues to push in low-temperature liquid perfluorohexanone, forming a continuous vaporization heat absorption forced convection.

[0015] In one possible implementation, the forced disengagement module includes a built-in explosive bolt or micro gas generator. When the integrated decision control center receives a BMS hardwire signal or abnormal high temperature signal indicating that the vehicle power battery has thermally runaway and may spread backward to the charging pile through the charging gun, the explosive bolt or micro gas generator is triggered. The instantaneously generated mechanical impulse forcibly overcomes the mechanical friction of the terminals and the resistance of the locking mechanism, ejecting the charging gun head from the vehicle socket and implementing rigid isolation in physical space.

[0016] In one possible implementation, the solid-state DC circuit breaker is composed of multiple anti-parallel silicon carbide MOSFET devices, with a nonlinear metal oxide varistor network connected in parallel on both sides to absorb the huge reverse peak voltage released by the distributed inductance of the liquid-cooled cable when the short-circuit current is interrupted in nanoseconds.

[0017] In one possible implementation, the high-frequency acoustic emission sensor array is not directly attached to the heat source, but is rigidly connected to the outer wall of the liquid-cooled working fluid distribution manifold at the output end of the charging pile through a stainless steel waveguide rod. The liquid is used as an excellent acoustic transmission medium to transmit the local boiling and collapse acoustic signal at the gun end to the inside of the pile body in a low-attenuation manner for signal analysis.

[0018] In one possible implementation, the protection timing evolution mechanism built into the integrated decision-making control center is as follows: at time T0, the risk of thermal runaway is confirmed; within 500 microseconds after T0, a solid-state DC circuit breaker is triggered to cut off the power supply; within 5 milliseconds after T0, a gunpowder-propelled rapid mechanical disconnect switch is opened to form a clear physical break; within 20 milliseconds after T0, an active phase change flooding fire extinguishing module is triggered to perform targeted cooling; if the concentration of gas escaping from the interface continues to rise or the temperature slope is not suppressed within 200 milliseconds after T0, the gun end is finally triggered to forcibly detach from the module.

[0019] At the level of its monitoring methods: The first dimension of defense is based on electrical frequency domain micro-stress detection. After hundreds or thousands of insertions and removals, the silver plating layer on the charging gun terminals will oxidize due to the exposed substrate, leading to a reduction in micro-contact spots. This invention cleverly utilizes the high-frequency switching ripple of the power electronics inside the charging pile or actively injects microvolt-level sweep signals to map the AC impedance spectrum of the terminal contact surface in real time. Before the terminal fully heats up, the drastic change in its capacitive impedance component will expose the hidden dangers of contact degradation.

[0020] The second-dimensional defense incorporates acoustic collapse detection from fluid dynamics. When extremely high heat flux density (exceeding the critical heat flux of the coolant) is generated at a local contact point of the terminal, even before the NTC temperature reacts, the coolant in close contact with the metal will undergo "supercooled boiling" or even "film boiling" at the microscopic interface. Tiny vapor bubbles rapidly condense and collapse in the surrounding cooler liquid, releasing transient acoustic emissions in the ultrasonic frequency band above 100 kHz. This system captures this "screaming sound of bursting bubbles" in the liquid cooling pipeline through a waveguide rod, achieving "zero-delay" sensing of extremely localized high temperatures and completely eliminating the heat conduction hysteresis caused by potting compound.

[0021] The third-dimensional defense supplements the interface escape gas concentration feedforward detection. Before the insulating material reaches its flash point, materials such as cross-linked polyethylene or polycarbonate will release trace amounts of carbon monoxide and volatile organic compounds upon thermal decomposition. By embedding a trace characteristic gas array sensor in the mechanical locking cavity of the charging gun head, the changes in the concentration of these characteristic gases are captured, and the rate of concentration change is used as the highest priority trigger parameter, further improving the accuracy and timeliness of thermal runaway early warning.

[0022] At the level of its protection system architecture, this invention transforms the charging pile from a unidirectional power transmission device into a defensive fortress with extremely strong self-rescue and anti-spread capabilities: Firstly, at the source of energy interruption, since mechanical contactors interrupting large currents can cause a prolonged arcing process (up to tens of milliseconds), this invention introduces a solid-state DC circuit breaker in conjunction with a propellant-driven isolating switch. Upon receiving an instruction, the silicon carbide device interrupts thousands of amperes of current without arcing within microseconds, and the propellant-driven switch then opens to create a physical safety distance, preventing even a trace of Joule heat from being injected into the fault point.

[0023] Secondly, for the already accumulated massive residual heat, this invention pioneers an active phase change flooding fire extinguishing mechanism. The system shuts off the conventional liquid-cooled pump, opens the high-pressure accumulator, and instantly injects an insulating extinguishing agent (perfluorohexanone) with an extremely low boiling point (e.g., 49 degrees Celsius) into the nozzle water jacket at extremely high pressure. Once these liquids come into contact with the scalding hot terminals, they instantly undergo a violent boiling phase change. Through the latent heat of vaporization, the local high temperature of several hundred degrees is forcibly pulled back below the safety line within seconds, while the vaporized and expanding inert gas escapes through the pipeline, carrying away the heat. This effectively controls the initial fire from both physical cooling and asphyxiation perspectives.

[0024] Finally, this invention establishes an ultimate "tail-cutting survival" defense—a forced detachment module for the charging gun tip. In real-world car accidents or battery aging incidents, tragedies often occur where the vehicle's power battery itself experiences thermal runaway, spewing high-temperature flames from the charging socket towards the charging station. Once this system detects this extremely dangerous "reverse attack" via wiring harness communication or a sniffer, it triggers an internal miniature gas generator or explosive bolt. The enormous mechanical impulse overcomes the friction of the locking mechanism, forcibly ejecting the charging gun from the vehicle. This not only preserves the valuable supercharging station host but also severs the physical bridge preventing the fire from spreading to the power grid or other vehicles charging alongside it.

[0025] The present invention has the following beneficial effects: The warning window for thermal runaway of charging piles has been forcibly advanced from the traditional "10 seconds before fire" to "several tens of minutes before the contact resistance just begins to deteriorate and the heat begins to show signs"; in terms of protection implementation, the traditional "passive waiting for burnout" has been upgraded to "active phase change deep cryogenic intervention" and "tail-cutting physical isolation", providing a rock-solid technical foundation for the absolute safe deployment of the next generation of megawatt-level supercharging networks. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart illustrating the high-power charging pile thermal runaway monitoring method of the present invention. Figure 2 This is a block diagram of the high-power charging pile thermal runaway protection system of the present invention; Figure 3 This is a schematic diagram of the structure of the electronic device of the present invention. Detailed Implementation

[0028] 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.

[0029] Figure 1 This is a flowchart illustrating the high-power charging pile thermal runaway monitoring method according to an embodiment of the present invention.

[0030] like Figure 2 The diagram shown illustrates the block diagram of the high-power charging pile thermal runaway protection system of the present invention. It should be noted that if substantially the same result is achieved, the method of this application is not based on... Figure 1 The sequence of processes shown is limited. Example 1

[0031] In this 600 kW supercharging system, even a slight increase of just 1 milliohm in contact resistance at the interface between the charging gun and the car socket terminal will generate a considerable concentrated heat source under a constant current of 600 amps. This is equivalent to lighting a high-power heating wire inside a tiny, sealed plastic cavity, and its destructive power is astonishing.

[0032] Traditional monitoring systems wrap thermal grease around the metal conductor of the terminal and insert an NTC thermistor. Due to the heat capacity of the grease and the surrounding polycarbonate casing, the heat generated by this concentrated heat source may have already caused the copper surface temperature to soar to 150 degrees Celsius inside the terminal, while the temperature rise detected by the NTC on the outside may only be slightly over 60 degrees Celsius, at which point the system still considers it to be within the normal range. This extremely fatal "thermal information time lag" is completely eliminated by the following three sets of pre-emptive physical detection methods of this invention.

[0033] Detection Dimension 1: Impedance Distortion Detection under Frequency Domain Alternating Electrical Stress This embodiment directly utilizes the downstream hardware of the DC-DC high-frequency isolation converter inside the charging pile to superimpose and inject a microvolt-level high-frequency sweeping sinusoidal signal with a frequency range of 150 kHz to 500 kHz onto the DC bus without affecting the main DC output process.

[0034] The microscopic contact surface of the terminals is not perfectly flat; it is composed of countless tiny contact spots. With mechanical wear and micro-arc erosion, the effective contact area decreases, and the oxide layer at the contact interface thickens. At this high frequency range, the oxide layer resembles countless miniature capacitors. As the oxide layer thickens (contact deteriorates), the capacitive impedance component in the high-frequency impedance spectrum undergoes a remarkably significant high-frequency shift.

[0035] The system's DSP controller synchronously extracts injected voltage disturbances and feedback high-frequency current ripples at a microsecond-level sampling rate, and calculates the imaginary part of the impedance using discrete Fourier transform. When the offset slope of the capacitive impedance component exceeds 12% of the reference value for five consecutive cycles, the system determines that the physical contact surface inside the terminal is in a deteriorated state. This is a purely physical electrical prediction that completely eliminates the lagging characteristic of "temperature," enabling it to issue the first warning before heat begins to accumulate abnormally.

[0036] Detection Dimension Two: Acoustic fingerprint capture of coolant micro-phase change; To address the strong heat masking effect, this embodiment uses a stainless steel rigid acoustic waveguide rod to tightly couple and install a wideband piezoelectric acoustic emission sensor at the liquid-cooled working fluid distribution manifold at the bottom of the charging pile (away from the high-temperature and high-pressure electromagnetic interference zone of the charging head).

[0037] The underlying fluid dynamics logic is as follows: Coolant (usually a 50% ethylene glycol aqueous solution) flows through the pipes, scouring the nozzle water jacket at a speed of 2 meters per second. When the temperature at a certain point on the terminal exceeds the local saturation temperature of the coolant (e.g., 105 degrees Celsius) due to poor contact, the extremely thin layer of liquid adhering to the metal wall will undergo a phase change instantaneously, generating micron-sized bubbles (supercooled boiling stage). Once these bubbles detach from the hot wall and enter the cooler mainstream fluid, they will collapse and perish instantly due to the internal and external pressure difference.

[0038] The collapse of the bubble releases a strong micro-shock wave. This high-frequency mechanical stress wave (with a frequency concentrated between 100 kHz and 300 kHz) travels extremely rapidly along the sealed, liquid-filled pipe (liquid is an excellent acoustic conductor) at a sound speed of about 1500 meters per second to the acoustic emission sensor at the bottom.

[0039] The system's FPGA high-speed signal processing board filters out the low-frequency mechanical noise of the water pump (typically below 20 kHz) in real time, and specifically counts the pulse count and absolute energy in the ultrasonic band. If the pulse count increases exponentially within 100 milliseconds, it indicates that the surface temperature of a point inside the nozzle, invisible to the naked eye, is rapidly rising, triggering a violent localized boiling of the liquid. This sensing speed is two orders of magnitude faster than that of an NTC temperature sensor.

[0040] Decision Integration and Third Dimension Verification: The main control system simultaneously receives impedance offset rate and ultrasonic quenching pulses. When both indicate deterioration, the system immediately initiates a power reduction procedure. However, to prevent extreme plastic carbonization events (such as user-inflicted gun drops causing internal cracks in the insulation frame), the system embeds a MEMS-based metal-oxide-semiconductor gas sensor array within the gun head latch cavity.

[0041] When the temperature approaches 200 degrees Celsius (before open flame combustion), the insulation layer of cross-linked polyethylene cables will thermally decompose and release a large amount of characteristic volatile organic compounds and carbon monoxide. Once the gas sensor detects a slight increase in carbon monoxide concentration, the system will no longer reduce power, but will directly characterize it as a "critical irreversible thermal runaway state," instantly bypassing all warning procedures and directly triggering the active intervention prevention line. Example 2

[0042] Once the central decision-making body issues a "thermal runaway criticality" ruling, the remaining time is measured in microseconds to milliseconds. The system's counterattack is precise and efficient.

[0043] Action sequence one: Microsecond-level severing of the electrical source; Traditionally, mechanical contactors are used to cut off 600-amp DC current. When the contacts separate, a high-energy arc several centimeters long is drawn out. Within tens of milliseconds of the arc burning, all the enormous energy is poured into the already overburdened fault point.

[0044] In this embodiment, the DC output circuit is connected in series with a solid-state circuit breaker composed of silicon carbide modules and a gunpowder-propelled fast disconnect switch.

[0045] The judgment is issued (set as time T0).

[0046] Within T0 plus 500 microseconds, the main controller cancels the gate drive signal of the silicon carbide MOSFET, and the device is hard-turned off in an extremely short time. The 600 amp current is instantly cut off to zero. The huge inductive reverse peak voltage generated by the forced current interruption in the cable is instantly absorbed and clamped by the zinc oxide varistor network connected in parallel across the solid-state circuit breaker.

[0047] Within T0 plus three milliseconds, the gunpowder micro-explosion generator ignites, pushing the moving contact of the mechanical disconnect switch to be withdrawn at a speed of 20 meters per second, forming a physical break point with air insulation, and completely eliminating the leakage current hazard of solid-state devices.

[0048] Action sequence two: Cryogenic submersion based on phase change vaporization endothermic reaction; Although the power supply was cut off, at the critical point of thermal runaway, the polycarbonate skeleton and copper busbar inside the gun head had accumulated a huge enthalpy value, and the temperature was still rising due to inertia, making it extremely easy to spontaneously combust.

[0049] At T0 plus 20 milliseconds, the system forcibly shuts down the main liquid cooling circulation pump, cutting off the flow of conventional coolant; at the same time, it opens the high-speed servo solenoid valve, connecting the independent energy storage pressure tank that has been pre-pressurized to 3.0 MPa.

[0050] The pressure tank is filled with perfluorohexanone. This is a highly efficient and environmentally friendly insulating fire extinguishing liquid. It is liquid at room temperature, but its boiling point is only 49 degrees Celsius, and it has extremely high latent heat of vaporization.

[0051] High-pressure perfluorohexanone is instantly injected into the water jacket of the nozzle and the gaps in the cable. When this liquid comes into contact with terminals or plastic frames at temperatures as high as 150 to 200 degrees Celsius, perfluorohexanone undergoes an extremely violent boiling vaporization phase transition.

[0052] The vaporization process rapidly absorbs the enormous latent heat of the surrounding environment, forcibly pulling the local temperature back below the absolute safety line of 50 degrees Celsius within 1 to 2 seconds. More importantly, the vaporized perfluorohexanone expands in volume dozens of times, forming a high concentration of extinguishing gas. This not only displaces the oxygen around the nozzle but also allows its molecular chains to capture combustion free radicals, effectively blocking the combustion reaction.

[0053] To prevent pipeline bursting due to vaporization, a back pressure relief valve (set at 1.5 MPa) is installed on the water jacket return pipeline. High-temperature gaseous perfluorohexanone opens the valve and is released into the atmosphere, carrying away heat. Subsequently, low-temperature liquid perfluorohexanone continues to flow into the nozzle under the impingement of the high-pressure tank, forming a continuous "forced phase change convection heat dissipation" that completely clears away the stubborn internal heat.

[0054] Action Sequence Three: A drastic and physical sacrifice in response to reverse fires; Example 1 and Sequence 2 primarily address faults caused by the charging pile's own terminals. However, a more dangerous externally input disaster exists: severe thermal runaway of the electric vehicle's battery pack, with intense flames or extremely high heat flowing back towards the charging pile via the charging socket and cables. In this case, all the aforementioned firefighting actions have limited effectiveness; ensuring the safety of the charging pile's main unit and the surrounding power grid becomes the core objective.

[0055] In this embodiment, an aerospace-grade miniature explosive bolt (or pneumatic release mechanism) is pre-embedded at the anti-pull joint between the gun body and the cable, or in the electronic locking mechanism inside the gun head.

[0056] The system continuously monitors the highest alarm messages from the BMS (such as cell failure messages) reported by the vehicle, or detects high concentrations of hydrogen fluoride gas and carbonate electrolyte vapor unique to lithium batteries using the gas sensor at the nozzle. Once a reverse battery fire is confirmed, the integrated decision-making center triggers the final bottom-line protocol: The explosive bolt is ignited. The explosive instantly severs the physical connection of the mechanical locking bolt, and the huge impulse released forces the huge insertion and extraction friction (usually up to 100 Newtons) between the gun terminal and the vehicle socket, violently ejecting the charging gun head from the burning car socket and causing it to fall to the ground.

[0057] This "mechanically forced disconnection" action severed the physical bridge that allowed the fire to spread along the wires to the charging host, preventing the supercharging equipment from being burned and preventing the fault from spreading to other charging piles in the same station through the bus, thus building a reliable safety firewall.

[0058] Comprehensive comparison and conclusion statement; To verify the technical advantages of the present invention, an extreme destructive comparison test was conducted between the "active phase change defense supercharger" (experimental group) using the technology of the present invention and the top-of-the-line "NTC temperature monitoring and mechanical circuit breaker supercharger" (control group) on the market, simulating severe terminal contact failure (artificially increasing the contact resistance to 50 milliohms and continuously operating at full load at 600 amps).

[0059] Data records reveal significant technological gaps: In the control group, the temperature exceeded the flash point of the insulating material within 4 seconds after the application of destructive impedance, but the deeply buried NTC probe only reached the shutdown threshold and triggered the mechanical switch at 12 seconds. By this time, the probe head had already caught fire, the internal parts were completely destroyed, and because the passive power cut-off could not remove the residual heat, the fire continued to burn for 3 minutes until it was manually extinguished.

[0060] In contrast, in the experimental group of this invention, the high-frequency AC impedance spectrum detected capacitive reactance variation and triggered an alarm within a mere 0.2 seconds (200 milliseconds) of applying destructive impedance; at 0.8 seconds, when the terminal just barely touched the boiling point of the coolant, the acoustic emission sensor captured the ultrasonic collapse pulse; and the main control center decisively issued a rapid disconnection and phase change flooding command within 1 second. The injection of perfluorohexanone caused the terminal temperature to be forcibly flattened and plummeted to 30 degrees Celsius after only reaching a maximum of 85 degrees Celsius. Apart from slight oxidation marks on the metal terminals of the nozzle, the entire system remained intact, with plastic parts and cables undamaged, and operation could be immediately restored after terminal replacement.

[0061] In summary, this invention spans three interdisciplinary fields: high-frequency domain diagnostics, acoustic microscopic detection, and phase change thermodynamics. By constructing a four-dimensional protection system—"multi-physics field hysteresis-free early warning—solid-state microsecond truncation—perfluorohexanone phase change cryogenic fire extinguishing—mechanical ejection tail severance"—it completely solves the technical shortcomings of traditional high-power charging piles that are slow to react and helpless in the face of thermal runaway. This invention provides reliable safety assurance for the global deployment of megawatt-level ultra-fast charging networks and also provides important reference for the underlying safety design specifications of new energy vehicle charging infrastructure.

[0062] For other details regarding the implementation techniques of each module in the above-described system, please refer to the description in the high-power charging pile thermal runaway monitoring method in Embodiment 1 above, which will not be repeated here.

[0063] It should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For system-type embodiments, since they are basically similar to method embodiments, the description is relatively simple; relevant parts can be referred to the descriptions in the method embodiments.

[0064] like Figure 3 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present disclosure. It illustrates a structural schematic diagram suitable for implementing the electronic device in the embodiment of the present disclosure. Figure 3 The electronic device shown is merely an example and should not be construed as limiting the functionality and scope of the embodiments disclosed herein.

[0065] like Figure 3 As shown, the electronic device includes a processor, a memory, and a communication interface. The memory stores a computer program, and when the processor executes the computer program, it implements the high-power charging pile thermal runaway monitoring method described in the various embodiments of this disclosure. The electronic device can exchange data with other devices or systems through the communication interface, enabling real-time updates and sharing of data information.

[0066] The processor in the aforementioned electronic device serves as its core, responsible for executing the computer program stored in the memory to implement various functions of the high-power charging pile thermal runaway monitoring method. The processor can employ a high-performance multi-core CPU or a dedicated chip to meet the demands of complex calculations and real-time processing. The memory stores the operating system, applications, data, and computer programs. In this embodiment, the memory stores the computer program implementing the high-power charging pile thermal runaway monitoring method. The memory can be RAM, ROM, Flash memory, or other types of non-volatile memory. The communication interface connects the electronic device to other devices or networks, enabling data transmission and exchange. In this embodiment, the communication interface supports multiple communication protocols and interface standards, such as Wi-Fi, Bluetooth, USB, and Ethernet, to meet communication needs in different scenarios.

[0067] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0068] According to the embodiments of the present disclosure, a computer-readable storage medium stores a computer program, which, when executed by a processor, implements the various functions of the high-power charging pile thermal runaway monitoring method described in the foregoing embodiments of the present disclosure.

[0069] The aforementioned computer-readable storage media include, but are not limited to: optical storage media (e.g., CD-ROM and DVD), magneto-optical storage media (e.g., MO), magnetic storage media (e.g., magnetic tape or portable hard drive), media with built-in rewritable non-volatile memory (e.g., memory card), and media with built-in ROM (e.g., ROM cartridge).

[0070] For a detailed description of this embodiment, please refer to the corresponding descriptions in the foregoing embodiments, which will not be repeated here.

[0071] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for monitoring thermal runaway in high-power charging piles, characterized in that, The method specifically includes the following steps: Electrical frequency domain micro-stress detection: Based on the active injection of a micro-volt high-frequency sinusoidal disturbance signal containing a wide frequency bandwidth by the power converter inside the charging pile, the high-frequency response current at the corresponding frequency is extracted synchronously, and the real-time broadband AC impedance spectrum between the charging gun terminal and the vehicle socket is calculated by Fourier transform. Acoustic detection of micro-boiling of cooling medium: A high-frequency acoustic emission sensor array is deployed on the liquid cooling circulation loop of the charging pile to capture acoustic signals inside the liquid cooling cable and the water jacket of the charging gun head in real time. Multidimensional state fusion and threshold determination: Extract the capacitive resistance component offset rate in the broadband AC impedance spectrum, and the ultrasonic frequency pulse count value in the acoustic signal caused by the rupture of local film boiling bubbles in the coolant; When the rising slope of the capacitive resistance component offset rate and the ultrasonic frequency band pulse count value both exceed the dynamic safety envelope within a set time window, it is determined that the charging system has contact degradation and thermal runaway precursors, and a graded protection action is triggered.

2. The method for monitoring thermal runaway of high-power charging piles according to claim 1, characterized in that, In the electrical frequency domain micro-stress detection step, the frequency range of the microvolt-level high-frequency sinusoidal disturbance signal is limited to between 150 kHz and 500 kHz.

3. The method for monitoring thermal runaway of high-power charging piles according to claim 1, characterized in that, The physical logic of the acoustic detection step of micro-boiling of the cooling working fluid is as follows: when poor contact of the charging gun terminal causes rapid heat generation, the local heat flux on the terminal surface will first cause the liquid cooling working fluid flowing against the wall to break through the saturated vapor pressure and generate microbubbles. By monitoring the transient acoustic emission energy bursts in the frequency range of 100 kHz to 300 kHz generated when these microbubbles condense and collapse in subcooled fluids, zero-delay sensing of temperature abrupt changes can be achieved.

4. The method for monitoring thermal runaway of high-power charging piles according to claim 1, characterized in that, The method also includes a feedforward detection step for the concentration of gas escaping from the interface: embedding a trace characteristic gas array sensor based on MEMS technology inside the mechanical locking cavity of the charging gun head.

5. A high-power charging pile protection system implementing the monitoring method according to any one of claims 1-4, characterized in that, The following modules work together: The hybrid high-speed interruption module, connected in series in the DC charging output main circuit, consists of a solid-state DC circuit breaker and a gunpowder-propelled fast mechanical disconnect switch connected in parallel; An active phase change flooding fire extinguishing module includes an independent energy storage pressure tank connected in parallel to a liquid cooling circulation loop. The energy storage pressure tank is pre-filled with high-pressure inert driving gas and perfluorohexanone phase change fire extinguishing medium. The gun-end forced disengagement module is integrated into the connection between the charging gun body and the charging pile cable or into the gun head mechanical locking structure. The integrated decision-making control center, when the monitoring method determines that thermal runaway is in an irreversible outbreak stage, triggers the hybrid rapid interruption module to cut off the power supply and simultaneously shuts down the normal liquid cooling circulation pump.

6. The high-power charging pile protection system according to claim 5, characterized in that, The active phase change flooding fire extinguishing module is designed with a bypass pressure relief and discharge channel in the pipeline topology. When perfluorohexanone is violently vaporized in the high-temperature zone of the nozzle, causing the pressure inside the pipeline to rise sharply to the explosion critical value, the pressure relief valve is passively opened. The vaporized perfluorohexanone carries a large amount of latent heat and is discharged into the atmosphere. At the same time, the energy storage pressure tank continues to push in low-temperature liquid perfluorohexanone, forming a continuous vaporization heat absorption forced convection.

7. The high-power charging pile protection system according to claim 5, characterized in that, The forced detachment module at the gun end includes a built-in explosive bolt or micro gas generator; when the integrated decision control center receives a BMS hard-wire signal or abnormal high temperature signal indicating that the vehicle power battery has thermal runaway and may spread in reverse to the charging pile through the charging gun, the explosive bolt or micro gas generator is triggered.

8. The high-power charging pile protection system according to claim 5, characterized in that, The solid-state DC circuit breaker is composed of multiple anti-parallel silicon carbide MOSFET devices, and a nonlinear metal oxide varistor network is connected in parallel on both sides of it.

9. The high-power charging pile protection system according to claim 5, characterized in that, The high-frequency acoustic emission sensor array is rigidly connected to the outer wall of the liquid-cooled working fluid distribution manifold at the output end of the charging pile via a stainless steel waveguide rod. Utilizing the liquid as an excellent acoustic transmission medium, the local boiling and collapse acoustic signal at the gun tip is transmitted to the inside of the pile body in a low-attenuation manner for signal analysis.

10. The high-power charging pile protection system according to claim 5, characterized in that, The built-in protection timing evolution mechanism of the integrated decision-making control center is as follows: The risk of thermal runaway was confirmed at time T0; T0 triggers the solid-state DC circuit breaker to cut off the power supply within 500 microseconds; Within five milliseconds of T0, the gunpowder-driven rapid mechanical disconnect switch is pulled open to form a clear physical break. Within 20 milliseconds of T0, the active phase change flooding fire extinguishing module is triggered to perform targeted cooling; If the concentration of gas escaping from the interface continues to rise or the temperature slope is not suppressed within T0 plus 200 milliseconds, the gun end will eventually be forced to detach from the module.

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